Local changes: - In contrib/libpcap/pcap/bpf.h, do not include pcap/dlt.h. Our system net/dlt.h is pulled in from net/bpf.h. - sys/net/dlt.h: Incorporate changes from libpcap 1.10.3. - lib/libpcap/Makefile: Update for libpcap 1.10.3. Changelog: https://git.tcpdump.org/libpcap/blob/95691ebe7564afa3faa5c6ba0dbd17e351be455a:/CHANGES Reviewed by: emaste Obtained from: https://www.tcpdump.org/release/libpcap-1.10.3.tar.gz Sponsored by: The FreeBSD Foundation
5588 lines
155 KiB
C
5588 lines
155 KiB
C
/*
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* pcap-linux.c: Packet capture interface to the Linux kernel
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*
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* Copyright (c) 2000 Torsten Landschoff <torsten@debian.org>
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* Sebastian Krahmer <krahmer@cs.uni-potsdam.de>
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*
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* License: BSD
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. The names of the authors may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* Modifications: Added PACKET_MMAP support
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* Paolo Abeni <paolo.abeni@email.it>
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* Added TPACKET_V3 support
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* Gabor Tatarka <gabor.tatarka@ericsson.com>
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*
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* based on previous works of:
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* Simon Patarin <patarin@cs.unibo.it>
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* Phil Wood <cpw@lanl.gov>
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*
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* Monitor-mode support for mac80211 includes code taken from the iw
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* command; the copyright notice for that code is
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*
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* Copyright (c) 2007, 2008 Johannes Berg
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* Copyright (c) 2007 Andy Lutomirski
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* Copyright (c) 2007 Mike Kershaw
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* Copyright (c) 2008 Gábor Stefanik
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#define _GNU_SOURCE
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <string.h>
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#include <limits.h>
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#include <sys/stat.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <sys/utsname.h>
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#include <sys/mman.h>
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#include <linux/if.h>
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#include <linux/if_packet.h>
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#include <linux/sockios.h>
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#include <linux/ethtool.h>
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#include <netinet/in.h>
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#include <linux/if_ether.h>
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#include <linux/if_arp.h>
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#include <poll.h>
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#include <dirent.h>
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#include <sys/eventfd.h>
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#include "pcap-int.h"
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#include "pcap/sll.h"
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#include "pcap/vlan.h"
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#include "pcap/can_socketcan.h"
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#include "diag-control.h"
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/*
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* We require TPACKET_V2 support.
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*/
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#ifndef TPACKET2_HDRLEN
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#error "Libpcap will only work if TPACKET_V2 is supported; you must build for a 2.6.27 or later kernel"
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#endif
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/* check for memory mapped access avaibility. We assume every needed
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* struct is defined if the macro TPACKET_HDRLEN is defined, because it
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* uses many ring related structs and macros */
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#ifdef TPACKET3_HDRLEN
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# define HAVE_TPACKET3
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#endif /* TPACKET3_HDRLEN */
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/*
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* Not all compilers that are used to compile code to run on Linux have
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* these builtins. For example, older versions of GCC don't, and at
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* least some people are doing cross-builds for MIPS with older versions
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* of GCC.
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*/
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#ifndef HAVE___ATOMIC_LOAD_N
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#define __atomic_load_n(ptr, memory_model) (*(ptr))
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#endif
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#ifndef HAVE___ATOMIC_STORE_N
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#define __atomic_store_n(ptr, val, memory_model) *(ptr) = (val)
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#endif
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#define packet_mmap_acquire(pkt) \
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(__atomic_load_n(&pkt->tp_status, __ATOMIC_ACQUIRE) != TP_STATUS_KERNEL)
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#define packet_mmap_release(pkt) \
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(__atomic_store_n(&pkt->tp_status, TP_STATUS_KERNEL, __ATOMIC_RELEASE))
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#define packet_mmap_v3_acquire(pkt) \
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(__atomic_load_n(&pkt->hdr.bh1.block_status, __ATOMIC_ACQUIRE) != TP_STATUS_KERNEL)
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#define packet_mmap_v3_release(pkt) \
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(__atomic_store_n(&pkt->hdr.bh1.block_status, TP_STATUS_KERNEL, __ATOMIC_RELEASE))
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#include <linux/types.h>
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#include <linux/filter.h>
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#ifdef HAVE_LINUX_NET_TSTAMP_H
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#include <linux/net_tstamp.h>
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#endif
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/*
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* For checking whether a device is a bonding device.
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*/
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#include <linux/if_bonding.h>
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/*
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* Got libnl?
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*/
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#ifdef HAVE_LIBNL
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#include <linux/nl80211.h>
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#include <netlink/genl/genl.h>
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#include <netlink/genl/family.h>
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#include <netlink/genl/ctrl.h>
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#include <netlink/msg.h>
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#include <netlink/attr.h>
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#endif /* HAVE_LIBNL */
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#ifndef HAVE_SOCKLEN_T
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typedef int socklen_t;
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#endif
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#define MAX_LINKHEADER_SIZE 256
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/*
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* When capturing on all interfaces we use this as the buffer size.
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* Should be bigger then all MTUs that occur in real life.
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* 64kB should be enough for now.
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*/
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#define BIGGER_THAN_ALL_MTUS (64*1024)
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/*
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* Private data for capturing on Linux PF_PACKET sockets.
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*/
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struct pcap_linux {
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long long sysfs_dropped; /* packets reported dropped by /sys/class/net/{if_name}/statistics/rx_{missed,fifo}_errors */
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struct pcap_stat stat;
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char *device; /* device name */
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int filter_in_userland; /* must filter in userland */
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int blocks_to_filter_in_userland;
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int must_do_on_close; /* stuff we must do when we close */
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int timeout; /* timeout for buffering */
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int cooked; /* using SOCK_DGRAM rather than SOCK_RAW */
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int ifindex; /* interface index of device we're bound to */
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int lo_ifindex; /* interface index of the loopback device */
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int netdown; /* we got an ENETDOWN and haven't resolved it */
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bpf_u_int32 oldmode; /* mode to restore when turning monitor mode off */
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char *mondevice; /* mac80211 monitor device we created */
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u_char *mmapbuf; /* memory-mapped region pointer */
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size_t mmapbuflen; /* size of region */
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int vlan_offset; /* offset at which to insert vlan tags; if -1, don't insert */
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u_int tp_version; /* version of tpacket_hdr for mmaped ring */
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u_int tp_hdrlen; /* hdrlen of tpacket_hdr for mmaped ring */
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u_char *oneshot_buffer; /* buffer for copy of packet */
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int poll_timeout; /* timeout to use in poll() */
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#ifdef HAVE_TPACKET3
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unsigned char *current_packet; /* Current packet within the TPACKET_V3 block. Move to next block if NULL. */
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int packets_left; /* Unhandled packets left within the block from previous call to pcap_read_linux_mmap_v3 in case of TPACKET_V3. */
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#endif
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int poll_breakloop_fd; /* fd to an eventfd to break from blocking operations */
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};
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/*
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* Stuff to do when we close.
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*/
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#define MUST_CLEAR_RFMON 0x00000001 /* clear rfmon (monitor) mode */
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#define MUST_DELETE_MONIF 0x00000002 /* delete monitor-mode interface */
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/*
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* Prototypes for internal functions and methods.
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*/
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static int get_if_flags(const char *, bpf_u_int32 *, char *);
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static int is_wifi(const char *);
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static void map_arphrd_to_dlt(pcap_t *, int, const char *, int);
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static int pcap_activate_linux(pcap_t *);
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static int setup_socket(pcap_t *, int);
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static int setup_mmapped(pcap_t *, int *);
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static int pcap_can_set_rfmon_linux(pcap_t *);
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static int pcap_inject_linux(pcap_t *, const void *, int);
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static int pcap_stats_linux(pcap_t *, struct pcap_stat *);
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static int pcap_setfilter_linux(pcap_t *, struct bpf_program *);
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static int pcap_setdirection_linux(pcap_t *, pcap_direction_t);
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static int pcap_set_datalink_linux(pcap_t *, int);
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static void pcap_cleanup_linux(pcap_t *);
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union thdr {
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struct tpacket2_hdr *h2;
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#ifdef HAVE_TPACKET3
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struct tpacket_block_desc *h3;
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#endif
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u_char *raw;
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};
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#define RING_GET_FRAME_AT(h, offset) (((u_char **)h->buffer)[(offset)])
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#define RING_GET_CURRENT_FRAME(h) RING_GET_FRAME_AT(h, h->offset)
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static void destroy_ring(pcap_t *handle);
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static int create_ring(pcap_t *handle, int *status);
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static int prepare_tpacket_socket(pcap_t *handle);
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static int pcap_read_linux_mmap_v2(pcap_t *, int, pcap_handler , u_char *);
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#ifdef HAVE_TPACKET3
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static int pcap_read_linux_mmap_v3(pcap_t *, int, pcap_handler , u_char *);
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#endif
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static int pcap_setnonblock_linux(pcap_t *p, int nonblock);
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static int pcap_getnonblock_linux(pcap_t *p);
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static void pcap_oneshot_linux(u_char *user, const struct pcap_pkthdr *h,
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const u_char *bytes);
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/*
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* In pre-3.0 kernels, the tp_vlan_tci field is set to whatever the
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* vlan_tci field in the skbuff is. 0 can either mean "not on a VLAN"
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* or "on VLAN 0". There is no flag set in the tp_status field to
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* distinguish between them.
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*
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* In 3.0 and later kernels, if there's a VLAN tag present, the tp_vlan_tci
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* field is set to the VLAN tag, and the TP_STATUS_VLAN_VALID flag is set
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* in the tp_status field, otherwise the tp_vlan_tci field is set to 0 and
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* the TP_STATUS_VLAN_VALID flag isn't set in the tp_status field.
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*
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* With a pre-3.0 kernel, we cannot distinguish between packets with no
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* VLAN tag and packets on VLAN 0, so we will mishandle some packets, and
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* there's nothing we can do about that.
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*
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* So, on those systems, which never set the TP_STATUS_VLAN_VALID flag, we
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* continue the behavior of earlier libpcaps, wherein we treated packets
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* with a VLAN tag of 0 as being packets without a VLAN tag rather than packets
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* on VLAN 0. We do this by treating packets with a tp_vlan_tci of 0 and
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* with the TP_STATUS_VLAN_VALID flag not set in tp_status as not having
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* VLAN tags. This does the right thing on 3.0 and later kernels, and
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* continues the old unfixably-imperfect behavior on pre-3.0 kernels.
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*
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* If TP_STATUS_VLAN_VALID isn't defined, we test it as the 0x10 bit; it
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* has that value in 3.0 and later kernels.
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*/
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#ifdef TP_STATUS_VLAN_VALID
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#define VLAN_VALID(hdr, hv) ((hv)->tp_vlan_tci != 0 || ((hdr)->tp_status & TP_STATUS_VLAN_VALID))
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#else
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/*
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* This is being compiled on a system that lacks TP_STATUS_VLAN_VALID,
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* so we testwith the value it has in the 3.0 and later kernels, so
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* we can test it if we're running on a system that has it. (If we're
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* running on a system that doesn't have it, it won't be set in the
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* tp_status field, so the tests of it will always fail; that means
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* we behave the way we did before we introduced this macro.)
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*/
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#define VLAN_VALID(hdr, hv) ((hv)->tp_vlan_tci != 0 || ((hdr)->tp_status & 0x10))
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#endif
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#ifdef TP_STATUS_VLAN_TPID_VALID
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# define VLAN_TPID(hdr, hv) (((hv)->tp_vlan_tpid || ((hdr)->tp_status & TP_STATUS_VLAN_TPID_VALID)) ? (hv)->tp_vlan_tpid : ETH_P_8021Q)
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#else
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# define VLAN_TPID(hdr, hv) ETH_P_8021Q
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#endif
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/*
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* Required select timeout if we're polling for an "interface disappeared"
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* indication - 1 millisecond.
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*/
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static const struct timeval netdown_timeout = {
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0, 1000 /* 1000 microseconds = 1 millisecond */
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};
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/*
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* Wrap some ioctl calls
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*/
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static int iface_get_id(int fd, const char *device, char *ebuf);
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static int iface_get_mtu(int fd, const char *device, char *ebuf);
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static int iface_get_arptype(int fd, const char *device, char *ebuf);
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static int iface_bind(int fd, int ifindex, char *ebuf, int protocol);
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static int enter_rfmon_mode(pcap_t *handle, int sock_fd,
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const char *device);
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static int iface_get_ts_types(const char *device, pcap_t *handle,
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char *ebuf);
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static int iface_get_offload(pcap_t *handle);
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static int fix_program(pcap_t *handle, struct sock_fprog *fcode);
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static int fix_offset(pcap_t *handle, struct bpf_insn *p);
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static int set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode);
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static int reset_kernel_filter(pcap_t *handle);
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static struct sock_filter total_insn
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= BPF_STMT(BPF_RET | BPF_K, 0);
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static struct sock_fprog total_fcode
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= { 1, &total_insn };
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static int iface_dsa_get_proto_info(const char *device, pcap_t *handle);
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pcap_t *
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pcap_create_interface(const char *device, char *ebuf)
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{
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pcap_t *handle;
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handle = PCAP_CREATE_COMMON(ebuf, struct pcap_linux);
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if (handle == NULL)
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return NULL;
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handle->activate_op = pcap_activate_linux;
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handle->can_set_rfmon_op = pcap_can_set_rfmon_linux;
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/*
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* See what time stamp types we support.
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*/
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if (iface_get_ts_types(device, handle, ebuf) == -1) {
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pcap_close(handle);
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return NULL;
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}
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/*
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* We claim that we support microsecond and nanosecond time
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* stamps.
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*
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* XXX - with adapter-supplied time stamps, can we choose
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* microsecond or nanosecond time stamps on arbitrary
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* adapters?
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*/
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handle->tstamp_precision_list = malloc(2 * sizeof(u_int));
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if (handle->tstamp_precision_list == NULL) {
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pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
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errno, "malloc");
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pcap_close(handle);
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return NULL;
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}
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handle->tstamp_precision_list[0] = PCAP_TSTAMP_PRECISION_MICRO;
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handle->tstamp_precision_list[1] = PCAP_TSTAMP_PRECISION_NANO;
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handle->tstamp_precision_count = 2;
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struct pcap_linux *handlep = handle->priv;
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handlep->poll_breakloop_fd = eventfd(0, EFD_NONBLOCK);
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return handle;
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}
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#ifdef HAVE_LIBNL
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/*
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* If interface {if_name} is a mac80211 driver, the file
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* /sys/class/net/{if_name}/phy80211 is a symlink to
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* /sys/class/ieee80211/{phydev_name}, for some {phydev_name}.
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*
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* On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
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* least, has a "wmaster0" device and a "wlan0" device; the
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* latter is the one with the IP address. Both show up in
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* "tcpdump -D" output. Capturing on the wmaster0 device
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* captures with 802.11 headers.
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*
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* airmon-ng searches through /sys/class/net for devices named
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* monN, starting with mon0; as soon as one *doesn't* exist,
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* it chooses that as the monitor device name. If the "iw"
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* command exists, it does
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*
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* iw dev {if_name} interface add {monif_name} type monitor
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*
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* where {monif_name} is the monitor device. It then (sigh) sleeps
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* .1 second, and then configures the device up. Otherwise, if
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* /sys/class/ieee80211/{phydev_name}/add_iface is a file, it writes
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* {mondev_name}, without a newline, to that file, and again (sigh)
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* sleeps .1 second, and then iwconfig's that device into monitor
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* mode and configures it up. Otherwise, you can't do monitor mode.
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*
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* All these devices are "glued" together by having the
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* /sys/class/net/{if_name}/phy80211 links pointing to the same
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* place, so, given a wmaster, wlan, or mon device, you can
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* find the other devices by looking for devices with
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* the same phy80211 link.
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*
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* To turn monitor mode off, delete the monitor interface,
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* either with
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*
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* iw dev {monif_name} interface del
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*
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* or by sending {monif_name}, with no NL, down
|
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* /sys/class/ieee80211/{phydev_name}/remove_iface
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*
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* Note: if you try to create a monitor device named "monN", and
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* there's already a "monN" device, it fails, as least with
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* the netlink interface (which is what iw uses), with a return
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* value of -ENFILE. (Return values are negative errnos.) We
|
|
* could probably use that to find an unused device.
|
|
*
|
|
* Yes, you can have multiple monitor devices for a given
|
|
* physical device.
|
|
*/
|
|
|
|
/*
|
|
* Is this a mac80211 device? If so, fill in the physical device path and
|
|
* return 1; if not, return 0. On an error, fill in handle->errbuf and
|
|
* return PCAP_ERROR.
|
|
*/
|
|
static int
|
|
get_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path,
|
|
size_t phydev_max_pathlen)
|
|
{
|
|
char *pathstr;
|
|
ssize_t bytes_read;
|
|
|
|
/*
|
|
* Generate the path string for the symlink to the physical device.
|
|
*/
|
|
if (asprintf(&pathstr, "/sys/class/net/%s/phy80211", device) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: Can't generate path name string for /sys/class/net device",
|
|
device);
|
|
return PCAP_ERROR;
|
|
}
|
|
bytes_read = readlink(pathstr, phydev_path, phydev_max_pathlen);
|
|
if (bytes_read == -1) {
|
|
if (errno == ENOENT || errno == EINVAL) {
|
|
/*
|
|
* Doesn't exist, or not a symlink; assume that
|
|
* means it's not a mac80211 device.
|
|
*/
|
|
free(pathstr);
|
|
return 0;
|
|
}
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "%s: Can't readlink %s", device, pathstr);
|
|
free(pathstr);
|
|
return PCAP_ERROR;
|
|
}
|
|
free(pathstr);
|
|
phydev_path[bytes_read] = '\0';
|
|
return 1;
|
|
}
|
|
|
|
struct nl80211_state {
|
|
struct nl_sock *nl_sock;
|
|
struct nl_cache *nl_cache;
|
|
struct genl_family *nl80211;
|
|
};
|
|
|
|
static int
|
|
nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device)
|
|
{
|
|
int err;
|
|
|
|
state->nl_sock = nl_socket_alloc();
|
|
if (!state->nl_sock) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to allocate netlink handle", device);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
if (genl_connect(state->nl_sock)) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to connect to generic netlink", device);
|
|
goto out_handle_destroy;
|
|
}
|
|
|
|
err = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache);
|
|
if (err < 0) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to allocate generic netlink cache: %s",
|
|
device, nl_geterror(-err));
|
|
goto out_handle_destroy;
|
|
}
|
|
|
|
state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
|
|
if (!state->nl80211) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: nl80211 not found", device);
|
|
goto out_cache_free;
|
|
}
|
|
|
|
return 0;
|
|
|
|
out_cache_free:
|
|
nl_cache_free(state->nl_cache);
|
|
out_handle_destroy:
|
|
nl_socket_free(state->nl_sock);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
static void
|
|
nl80211_cleanup(struct nl80211_state *state)
|
|
{
|
|
genl_family_put(state->nl80211);
|
|
nl_cache_free(state->nl_cache);
|
|
nl_socket_free(state->nl_sock);
|
|
}
|
|
|
|
static int
|
|
del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
|
|
const char *device, const char *mondevice);
|
|
|
|
static int
|
|
add_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
|
|
const char *device, const char *mondevice)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
int ifindex;
|
|
struct nl_msg *msg;
|
|
int err;
|
|
|
|
ifindex = iface_get_id(sock_fd, device, handle->errbuf);
|
|
if (ifindex == -1)
|
|
return PCAP_ERROR;
|
|
|
|
msg = nlmsg_alloc();
|
|
if (!msg) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to allocate netlink msg", device);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
|
|
0, NL80211_CMD_NEW_INTERFACE, 0);
|
|
NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
|
|
DIAG_OFF_NARROWING
|
|
NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
|
|
DIAG_ON_NARROWING
|
|
NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);
|
|
|
|
err = nl_send_auto_complete(state->nl_sock, msg);
|
|
if (err < 0) {
|
|
if (err == -NLE_FAILURE) {
|
|
/*
|
|
* Device not available; our caller should just
|
|
* keep trying. (libnl 2.x maps ENFILE to
|
|
* NLE_FAILURE; it can also map other errors
|
|
* to that, but there's not much we can do
|
|
* about that.)
|
|
*/
|
|
nlmsg_free(msg);
|
|
return 0;
|
|
} else {
|
|
/*
|
|
* Real failure, not just "that device is not
|
|
* available.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: nl_send_auto_complete failed adding %s interface: %s",
|
|
device, mondevice, nl_geterror(-err));
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
err = nl_wait_for_ack(state->nl_sock);
|
|
if (err < 0) {
|
|
if (err == -NLE_FAILURE) {
|
|
/*
|
|
* Device not available; our caller should just
|
|
* keep trying. (libnl 2.x maps ENFILE to
|
|
* NLE_FAILURE; it can also map other errors
|
|
* to that, but there's not much we can do
|
|
* about that.)
|
|
*/
|
|
nlmsg_free(msg);
|
|
return 0;
|
|
} else {
|
|
/*
|
|
* Real failure, not just "that device is not
|
|
* available.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: nl_wait_for_ack failed adding %s interface: %s",
|
|
device, mondevice, nl_geterror(-err));
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Success.
|
|
*/
|
|
nlmsg_free(msg);
|
|
|
|
/*
|
|
* Try to remember the monitor device.
|
|
*/
|
|
handlep->mondevice = strdup(mondevice);
|
|
if (handlep->mondevice == NULL) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "strdup");
|
|
/*
|
|
* Get rid of the monitor device.
|
|
*/
|
|
del_mon_if(handle, sock_fd, state, device, mondevice);
|
|
return PCAP_ERROR;
|
|
}
|
|
return 1;
|
|
|
|
nla_put_failure:
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: nl_put failed adding %s interface",
|
|
device, mondevice);
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
static int
|
|
del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state,
|
|
const char *device, const char *mondevice)
|
|
{
|
|
int ifindex;
|
|
struct nl_msg *msg;
|
|
int err;
|
|
|
|
ifindex = iface_get_id(sock_fd, mondevice, handle->errbuf);
|
|
if (ifindex == -1)
|
|
return PCAP_ERROR;
|
|
|
|
msg = nlmsg_alloc();
|
|
if (!msg) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to allocate netlink msg", device);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
|
|
0, NL80211_CMD_DEL_INTERFACE, 0);
|
|
NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
|
|
|
|
err = nl_send_auto_complete(state->nl_sock, msg);
|
|
if (err < 0) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: nl_send_auto_complete failed deleting %s interface: %s",
|
|
device, mondevice, nl_geterror(-err));
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
err = nl_wait_for_ack(state->nl_sock);
|
|
if (err < 0) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: nl_wait_for_ack failed adding %s interface: %s",
|
|
device, mondevice, nl_geterror(-err));
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* Success.
|
|
*/
|
|
nlmsg_free(msg);
|
|
return 1;
|
|
|
|
nla_put_failure:
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: nl_put failed deleting %s interface",
|
|
device, mondevice);
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
#endif /* HAVE_LIBNL */
|
|
|
|
static int pcap_protocol(pcap_t *handle)
|
|
{
|
|
int protocol;
|
|
|
|
protocol = handle->opt.protocol;
|
|
if (protocol == 0)
|
|
protocol = ETH_P_ALL;
|
|
|
|
return htons(protocol);
|
|
}
|
|
|
|
static int
|
|
pcap_can_set_rfmon_linux(pcap_t *handle)
|
|
{
|
|
#ifdef HAVE_LIBNL
|
|
char phydev_path[PATH_MAX+1];
|
|
int ret;
|
|
#endif
|
|
|
|
if (strcmp(handle->opt.device, "any") == 0) {
|
|
/*
|
|
* Monitor mode makes no sense on the "any" device.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
#ifdef HAVE_LIBNL
|
|
/*
|
|
* Bleah. There doesn't seem to be a way to ask a mac80211
|
|
* device, through libnl, whether it supports monitor mode;
|
|
* we'll just check whether the device appears to be a
|
|
* mac80211 device and, if so, assume the device supports
|
|
* monitor mode.
|
|
*/
|
|
ret = get_mac80211_phydev(handle, handle->opt.device, phydev_path,
|
|
PATH_MAX);
|
|
if (ret < 0)
|
|
return ret; /* error */
|
|
if (ret == 1)
|
|
return 1; /* mac80211 device */
|
|
#endif
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Grabs the number of missed packets by the interface from
|
|
* /sys/class/net/{if_name}/statistics/rx_{missed,fifo}_errors.
|
|
*
|
|
* Compared to /proc/net/dev this avoids counting software drops,
|
|
* but may be unimplemented and just return 0.
|
|
* The author has found no straigthforward way to check for support.
|
|
*/
|
|
static long long int
|
|
linux_get_stat(const char * if_name, const char * stat) {
|
|
ssize_t bytes_read;
|
|
int fd;
|
|
char buffer[PATH_MAX];
|
|
|
|
snprintf(buffer, sizeof(buffer), "/sys/class/net/%s/statistics/%s", if_name, stat);
|
|
fd = open(buffer, O_RDONLY);
|
|
if (fd == -1)
|
|
return 0;
|
|
|
|
bytes_read = read(fd, buffer, sizeof(buffer) - 1);
|
|
close(fd);
|
|
if (bytes_read == -1)
|
|
return 0;
|
|
buffer[bytes_read] = '\0';
|
|
|
|
return strtoll(buffer, NULL, 10);
|
|
}
|
|
|
|
static long long int
|
|
linux_if_drops(const char * if_name)
|
|
{
|
|
long long int missed = linux_get_stat(if_name, "rx_missed_errors");
|
|
long long int fifo = linux_get_stat(if_name, "rx_fifo_errors");
|
|
return missed + fifo;
|
|
}
|
|
|
|
|
|
/*
|
|
* Monitor mode is kind of interesting because we have to reset the
|
|
* interface before exiting. The problem can't really be solved without
|
|
* some daemon taking care of managing usage counts. If we put the
|
|
* interface into monitor mode, we set a flag indicating that we must
|
|
* take it out of that mode when the interface is closed, and, when
|
|
* closing the interface, if that flag is set we take it out of monitor
|
|
* mode.
|
|
*/
|
|
|
|
static void pcap_cleanup_linux( pcap_t *handle )
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
#ifdef HAVE_LIBNL
|
|
struct nl80211_state nlstate;
|
|
int ret;
|
|
#endif /* HAVE_LIBNL */
|
|
|
|
if (handlep->must_do_on_close != 0) {
|
|
/*
|
|
* There's something we have to do when closing this
|
|
* pcap_t.
|
|
*/
|
|
#ifdef HAVE_LIBNL
|
|
if (handlep->must_do_on_close & MUST_DELETE_MONIF) {
|
|
ret = nl80211_init(handle, &nlstate, handlep->device);
|
|
if (ret >= 0) {
|
|
ret = del_mon_if(handle, handle->fd, &nlstate,
|
|
handlep->device, handlep->mondevice);
|
|
nl80211_cleanup(&nlstate);
|
|
}
|
|
if (ret < 0) {
|
|
fprintf(stderr,
|
|
"Can't delete monitor interface %s (%s).\n"
|
|
"Please delete manually.\n",
|
|
handlep->mondevice, handle->errbuf);
|
|
}
|
|
}
|
|
#endif /* HAVE_LIBNL */
|
|
|
|
/*
|
|
* Take this pcap out of the list of pcaps for which we
|
|
* have to take the interface out of some mode.
|
|
*/
|
|
pcap_remove_from_pcaps_to_close(handle);
|
|
}
|
|
|
|
if (handle->fd != -1) {
|
|
/*
|
|
* Destroy the ring buffer (assuming we've set it up),
|
|
* and unmap it if it's mapped.
|
|
*/
|
|
destroy_ring(handle);
|
|
}
|
|
|
|
if (handlep->oneshot_buffer != NULL) {
|
|
free(handlep->oneshot_buffer);
|
|
handlep->oneshot_buffer = NULL;
|
|
}
|
|
|
|
if (handlep->mondevice != NULL) {
|
|
free(handlep->mondevice);
|
|
handlep->mondevice = NULL;
|
|
}
|
|
if (handlep->device != NULL) {
|
|
free(handlep->device);
|
|
handlep->device = NULL;
|
|
}
|
|
|
|
if (handlep->poll_breakloop_fd != -1) {
|
|
close(handlep->poll_breakloop_fd);
|
|
handlep->poll_breakloop_fd = -1;
|
|
}
|
|
pcap_cleanup_live_common(handle);
|
|
}
|
|
|
|
#ifdef HAVE_TPACKET3
|
|
/*
|
|
* Some versions of TPACKET_V3 have annoying bugs/misfeatures
|
|
* around which we have to work. Determine if we have those
|
|
* problems or not.
|
|
* 3.19 is the first release with a fixed version of
|
|
* TPACKET_V3. We treat anything before that as
|
|
* not having a fixed version; that may really mean
|
|
* it has *no* version.
|
|
*/
|
|
static int has_broken_tpacket_v3(void)
|
|
{
|
|
struct utsname utsname;
|
|
const char *release;
|
|
long major, minor;
|
|
int matches, verlen;
|
|
|
|
/* No version information, assume broken. */
|
|
if (uname(&utsname) == -1)
|
|
return 1;
|
|
release = utsname.release;
|
|
|
|
/* A malformed version, ditto. */
|
|
matches = sscanf(release, "%ld.%ld%n", &major, &minor, &verlen);
|
|
if (matches != 2)
|
|
return 1;
|
|
if (release[verlen] != '.' && release[verlen] != '\0')
|
|
return 1;
|
|
|
|
/* OK, a fixed version. */
|
|
if (major > 3 || (major == 3 && minor >= 19))
|
|
return 0;
|
|
|
|
/* Too old :( */
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Set the timeout to be used in poll() with memory-mapped packet capture.
|
|
*/
|
|
static void
|
|
set_poll_timeout(struct pcap_linux *handlep)
|
|
{
|
|
#ifdef HAVE_TPACKET3
|
|
int broken_tpacket_v3 = has_broken_tpacket_v3();
|
|
#endif
|
|
if (handlep->timeout == 0) {
|
|
#ifdef HAVE_TPACKET3
|
|
/*
|
|
* XXX - due to a set of (mis)features in the TPACKET_V3
|
|
* kernel code prior to the 3.19 kernel, blocking forever
|
|
* with a TPACKET_V3 socket can, if few packets are
|
|
* arriving and passing the socket filter, cause most
|
|
* packets to be dropped. See libpcap issue #335 for the
|
|
* full painful story.
|
|
*
|
|
* The workaround is to have poll() time out very quickly,
|
|
* so we grab the frames handed to us, and return them to
|
|
* the kernel, ASAP.
|
|
*/
|
|
if (handlep->tp_version == TPACKET_V3 && broken_tpacket_v3)
|
|
handlep->poll_timeout = 1; /* don't block for very long */
|
|
else
|
|
#endif
|
|
handlep->poll_timeout = -1; /* block forever */
|
|
} else if (handlep->timeout > 0) {
|
|
#ifdef HAVE_TPACKET3
|
|
/*
|
|
* For TPACKET_V3, the timeout is handled by the kernel,
|
|
* so block forever; that way, we don't get extra timeouts.
|
|
* Don't do that if we have a broken TPACKET_V3, though.
|
|
*/
|
|
if (handlep->tp_version == TPACKET_V3 && !broken_tpacket_v3)
|
|
handlep->poll_timeout = -1; /* block forever, let TPACKET_V3 wake us up */
|
|
else
|
|
#endif
|
|
handlep->poll_timeout = handlep->timeout; /* block for that amount of time */
|
|
} else {
|
|
/*
|
|
* Non-blocking mode; we call poll() to pick up error
|
|
* indications, but we don't want it to wait for
|
|
* anything.
|
|
*/
|
|
handlep->poll_timeout = 0;
|
|
}
|
|
}
|
|
|
|
static void pcap_breakloop_linux(pcap_t *handle)
|
|
{
|
|
pcap_breakloop_common(handle);
|
|
struct pcap_linux *handlep = handle->priv;
|
|
|
|
uint64_t value = 1;
|
|
/* XXX - what if this fails? */
|
|
if (handlep->poll_breakloop_fd != -1)
|
|
(void)write(handlep->poll_breakloop_fd, &value, sizeof(value));
|
|
}
|
|
|
|
/*
|
|
* Set the offset at which to insert VLAN tags.
|
|
* That should be the offset of the type field.
|
|
*/
|
|
static void
|
|
set_vlan_offset(pcap_t *handle)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
|
|
switch (handle->linktype) {
|
|
|
|
case DLT_EN10MB:
|
|
/*
|
|
* The type field is after the destination and source
|
|
* MAC address.
|
|
*/
|
|
handlep->vlan_offset = 2 * ETH_ALEN;
|
|
break;
|
|
|
|
case DLT_LINUX_SLL:
|
|
/*
|
|
* The type field is in the last 2 bytes of the
|
|
* DLT_LINUX_SLL header.
|
|
*/
|
|
handlep->vlan_offset = SLL_HDR_LEN - 2;
|
|
break;
|
|
|
|
default:
|
|
handlep->vlan_offset = -1; /* unknown */
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get a handle for a live capture from the given device. You can
|
|
* pass NULL as device to get all packages (without link level
|
|
* information of course). If you pass 1 as promisc the interface
|
|
* will be set to promiscuous mode (XXX: I think this usage should
|
|
* be deprecated and functions be added to select that later allow
|
|
* modification of that values -- Torsten).
|
|
*/
|
|
static int
|
|
pcap_activate_linux(pcap_t *handle)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
const char *device;
|
|
int is_any_device;
|
|
struct ifreq ifr;
|
|
int status = 0;
|
|
int status2 = 0;
|
|
int ret;
|
|
|
|
device = handle->opt.device;
|
|
|
|
/*
|
|
* Make sure the name we were handed will fit into the ioctls we
|
|
* might perform on the device; if not, return a "No such device"
|
|
* indication, as the Linux kernel shouldn't support creating
|
|
* a device whose name won't fit into those ioctls.
|
|
*
|
|
* "Will fit" means "will fit, complete with a null terminator",
|
|
* so if the length, which does *not* include the null terminator,
|
|
* is greater than *or equal to* the size of the field into which
|
|
* we'll be copying it, that won't fit.
|
|
*/
|
|
if (strlen(device) >= sizeof(ifr.ifr_name)) {
|
|
/*
|
|
* There's nothing more to say, so clear the error
|
|
* message.
|
|
*/
|
|
handle->errbuf[0] = '\0';
|
|
status = PCAP_ERROR_NO_SUCH_DEVICE;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* Turn a negative snapshot value (invalid), a snapshot value of
|
|
* 0 (unspecified), or a value bigger than the normal maximum
|
|
* value, into the maximum allowed value.
|
|
*
|
|
* If some application really *needs* a bigger snapshot
|
|
* length, we should just increase MAXIMUM_SNAPLEN.
|
|
*/
|
|
if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
|
|
handle->snapshot = MAXIMUM_SNAPLEN;
|
|
|
|
handlep->device = strdup(device);
|
|
if (handlep->device == NULL) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "strdup");
|
|
status = PCAP_ERROR;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* The "any" device is a special device which causes us not
|
|
* to bind to a particular device and thus to look at all
|
|
* devices.
|
|
*/
|
|
is_any_device = (strcmp(device, "any") == 0);
|
|
if (is_any_device) {
|
|
if (handle->opt.promisc) {
|
|
handle->opt.promisc = 0;
|
|
/* Just a warning. */
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Promiscuous mode not supported on the \"any\" device");
|
|
status = PCAP_WARNING_PROMISC_NOTSUP;
|
|
}
|
|
}
|
|
|
|
/* copy timeout value */
|
|
handlep->timeout = handle->opt.timeout;
|
|
|
|
/*
|
|
* If we're in promiscuous mode, then we probably want
|
|
* to see when the interface drops packets too, so get an
|
|
* initial count from
|
|
* /sys/class/net/{if_name}/statistics/rx_{missed,fifo}_errors
|
|
*/
|
|
if (handle->opt.promisc)
|
|
handlep->sysfs_dropped = linux_if_drops(handlep->device);
|
|
|
|
/*
|
|
* If the "any" device is specified, try to open a SOCK_DGRAM.
|
|
* Otherwise, open a SOCK_RAW.
|
|
*/
|
|
ret = setup_socket(handle, is_any_device);
|
|
if (ret < 0) {
|
|
/*
|
|
* Fatal error; the return value is the error code,
|
|
* and handle->errbuf has been set to an appropriate
|
|
* error message.
|
|
*/
|
|
status = ret;
|
|
goto fail;
|
|
}
|
|
/*
|
|
* Success.
|
|
* Try to set up memory-mapped access.
|
|
*/
|
|
ret = setup_mmapped(handle, &status);
|
|
if (ret == -1) {
|
|
/*
|
|
* We failed to set up to use it, or the
|
|
* kernel supports it, but we failed to
|
|
* enable it. status has been set to the
|
|
* error status to return and, if it's
|
|
* PCAP_ERROR, handle->errbuf contains
|
|
* the error message.
|
|
*/
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* We succeeded. status has been set to the status to return,
|
|
* which might be 0, or might be a PCAP_WARNING_ value.
|
|
*/
|
|
/*
|
|
* Now that we have activated the mmap ring, we can
|
|
* set the correct protocol.
|
|
*/
|
|
if ((status2 = iface_bind(handle->fd, handlep->ifindex,
|
|
handle->errbuf, pcap_protocol(handle))) != 0) {
|
|
status = status2;
|
|
goto fail;
|
|
}
|
|
|
|
handle->inject_op = pcap_inject_linux;
|
|
handle->setfilter_op = pcap_setfilter_linux;
|
|
handle->setdirection_op = pcap_setdirection_linux;
|
|
handle->set_datalink_op = pcap_set_datalink_linux;
|
|
handle->setnonblock_op = pcap_setnonblock_linux;
|
|
handle->getnonblock_op = pcap_getnonblock_linux;
|
|
handle->cleanup_op = pcap_cleanup_linux;
|
|
handle->stats_op = pcap_stats_linux;
|
|
handle->breakloop_op = pcap_breakloop_linux;
|
|
|
|
switch (handlep->tp_version) {
|
|
|
|
case TPACKET_V2:
|
|
handle->read_op = pcap_read_linux_mmap_v2;
|
|
break;
|
|
#ifdef HAVE_TPACKET3
|
|
case TPACKET_V3:
|
|
handle->read_op = pcap_read_linux_mmap_v3;
|
|
break;
|
|
#endif
|
|
}
|
|
handle->oneshot_callback = pcap_oneshot_linux;
|
|
handle->selectable_fd = handle->fd;
|
|
|
|
return status;
|
|
|
|
fail:
|
|
pcap_cleanup_linux(handle);
|
|
return status;
|
|
}
|
|
|
|
static int
|
|
pcap_set_datalink_linux(pcap_t *handle, int dlt)
|
|
{
|
|
handle->linktype = dlt;
|
|
|
|
/*
|
|
* Update the offset at which to insert VLAN tags for the
|
|
* new link-layer type.
|
|
*/
|
|
set_vlan_offset(handle);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* linux_check_direction()
|
|
*
|
|
* Do checks based on packet direction.
|
|
*/
|
|
static inline int
|
|
linux_check_direction(const pcap_t *handle, const struct sockaddr_ll *sll)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
|
|
if (sll->sll_pkttype == PACKET_OUTGOING) {
|
|
/*
|
|
* Outgoing packet.
|
|
* If this is from the loopback device, reject it;
|
|
* we'll see the packet as an incoming packet as well,
|
|
* and we don't want to see it twice.
|
|
*/
|
|
if (sll->sll_ifindex == handlep->lo_ifindex)
|
|
return 0;
|
|
|
|
/*
|
|
* If this is an outgoing CAN or CAN FD frame, and
|
|
* the user doesn't only want outgoing packets,
|
|
* reject it; CAN devices and drivers, and the CAN
|
|
* stack, always arrange to loop back transmitted
|
|
* packets, so they also appear as incoming packets.
|
|
* We don't want duplicate packets, and we can't
|
|
* easily distinguish packets looped back by the CAN
|
|
* layer than those received by the CAN layer, so we
|
|
* eliminate this packet instead.
|
|
*
|
|
* We check whether this is a CAN or CAN FD frame
|
|
* by checking whether the device's hardware type
|
|
* is ARPHRD_CAN.
|
|
*/
|
|
if (sll->sll_hatype == ARPHRD_CAN &&
|
|
handle->direction != PCAP_D_OUT)
|
|
return 0;
|
|
|
|
/*
|
|
* If the user only wants incoming packets, reject it.
|
|
*/
|
|
if (handle->direction == PCAP_D_IN)
|
|
return 0;
|
|
} else {
|
|
/*
|
|
* Incoming packet.
|
|
* If the user only wants outgoing packets, reject it.
|
|
*/
|
|
if (handle->direction == PCAP_D_OUT)
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Check whether the device to which the pcap_t is bound still exists.
|
|
* We do so by asking what address the socket is bound to, and checking
|
|
* whether the ifindex in the address is -1, meaning "that device is gone",
|
|
* or some other value, meaning "that device still exists".
|
|
*/
|
|
static int
|
|
device_still_exists(pcap_t *handle)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
struct sockaddr_ll addr;
|
|
socklen_t addr_len;
|
|
|
|
/*
|
|
* If handlep->ifindex is -1, the socket isn't bound, meaning
|
|
* we're capturing on the "any" device; that device never
|
|
* disappears. (It should also never be configured down, so
|
|
* we shouldn't even get here, but let's make sure.)
|
|
*/
|
|
if (handlep->ifindex == -1)
|
|
return (1); /* it's still here */
|
|
|
|
/*
|
|
* OK, now try to get the address for the socket.
|
|
*/
|
|
addr_len = sizeof (addr);
|
|
if (getsockname(handle->fd, (struct sockaddr *) &addr, &addr_len) == -1) {
|
|
/*
|
|
* Error - report an error and return -1.
|
|
*/
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "getsockname failed");
|
|
return (-1);
|
|
}
|
|
if (addr.sll_ifindex == -1) {
|
|
/*
|
|
* This means the device went away.
|
|
*/
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* The device presumably just went down.
|
|
*/
|
|
return (1);
|
|
}
|
|
|
|
static int
|
|
pcap_inject_linux(pcap_t *handle, const void *buf, int size)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
int ret;
|
|
|
|
if (handlep->ifindex == -1) {
|
|
/*
|
|
* We don't support sending on the "any" device.
|
|
*/
|
|
pcap_strlcpy(handle->errbuf,
|
|
"Sending packets isn't supported on the \"any\" device",
|
|
PCAP_ERRBUF_SIZE);
|
|
return (-1);
|
|
}
|
|
|
|
if (handlep->cooked) {
|
|
/*
|
|
* We don't support sending on cooked-mode sockets.
|
|
*
|
|
* XXX - how do you send on a bound cooked-mode
|
|
* socket?
|
|
* Is a "sendto()" required there?
|
|
*/
|
|
pcap_strlcpy(handle->errbuf,
|
|
"Sending packets isn't supported in cooked mode",
|
|
PCAP_ERRBUF_SIZE);
|
|
return (-1);
|
|
}
|
|
|
|
ret = (int)send(handle->fd, buf, size, 0);
|
|
if (ret == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "send");
|
|
return (-1);
|
|
}
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Get the statistics for the given packet capture handle.
|
|
*/
|
|
static int
|
|
pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
#ifdef HAVE_TPACKET3
|
|
/*
|
|
* For sockets using TPACKET_V2, the extra stuff at the end
|
|
* of a struct tpacket_stats_v3 will not be filled in, and
|
|
* we don't look at it so this is OK even for those sockets.
|
|
* In addition, the PF_PACKET socket code in the kernel only
|
|
* uses the length parameter to compute how much data to
|
|
* copy out and to indicate how much data was copied out, so
|
|
* it's OK to base it on the size of a struct tpacket_stats.
|
|
*
|
|
* XXX - it's probably OK, in fact, to just use a
|
|
* struct tpacket_stats for V3 sockets, as we don't
|
|
* care about the tp_freeze_q_cnt stat.
|
|
*/
|
|
struct tpacket_stats_v3 kstats;
|
|
#else /* HAVE_TPACKET3 */
|
|
struct tpacket_stats kstats;
|
|
#endif /* HAVE_TPACKET3 */
|
|
socklen_t len = sizeof (struct tpacket_stats);
|
|
|
|
long long if_dropped = 0;
|
|
|
|
/*
|
|
* To fill in ps_ifdrop, we parse
|
|
* /sys/class/net/{if_name}/statistics/rx_{missed,fifo}_errors
|
|
* for the numbers
|
|
*/
|
|
if (handle->opt.promisc)
|
|
{
|
|
/*
|
|
* XXX - is there any reason to do this by remembering
|
|
* the last counts value, subtracting it from the
|
|
* current counts value, and adding that to stat.ps_ifdrop,
|
|
* maintaining stat.ps_ifdrop as a count, rather than just
|
|
* saving the *initial* counts value and setting
|
|
* stat.ps_ifdrop to the difference between the current
|
|
* value and the initial value?
|
|
*
|
|
* One reason might be to handle the count wrapping
|
|
* around, on platforms where the count is 32 bits
|
|
* and where you might get more than 2^32 dropped
|
|
* packets; is there any other reason?
|
|
*
|
|
* (We maintain the count as a long long int so that,
|
|
* if the kernel maintains the counts as 64-bit even
|
|
* on 32-bit platforms, we can handle the real count.
|
|
*
|
|
* Unfortunately, we can't report 64-bit counts; we
|
|
* need a better API for reporting statistics, such as
|
|
* one that reports them in a style similar to the
|
|
* pcapng Interface Statistics Block, so that 1) the
|
|
* counts are 64-bit, 2) it's easier to add new statistics
|
|
* without breaking the ABI, and 3) it's easier to
|
|
* indicate to a caller that wants one particular
|
|
* statistic that it's not available by just not supplying
|
|
* it.)
|
|
*/
|
|
if_dropped = handlep->sysfs_dropped;
|
|
handlep->sysfs_dropped = linux_if_drops(handlep->device);
|
|
handlep->stat.ps_ifdrop += (u_int)(handlep->sysfs_dropped - if_dropped);
|
|
}
|
|
|
|
/*
|
|
* Try to get the packet counts from the kernel.
|
|
*/
|
|
if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS,
|
|
&kstats, &len) > -1) {
|
|
/*
|
|
* "ps_recv" counts only packets that *passed* the
|
|
* filter, not packets that didn't pass the filter.
|
|
* This includes packets later dropped because we
|
|
* ran out of buffer space.
|
|
*
|
|
* "ps_drop" counts packets dropped because we ran
|
|
* out of buffer space. It doesn't count packets
|
|
* dropped by the interface driver. It counts only
|
|
* packets that passed the filter.
|
|
*
|
|
* See above for ps_ifdrop.
|
|
*
|
|
* Both statistics include packets not yet read from
|
|
* the kernel by libpcap, and thus not yet seen by
|
|
* the application.
|
|
*
|
|
* In "linux/net/packet/af_packet.c", at least in 2.6.27
|
|
* through 5.6 kernels, "tp_packets" is incremented for
|
|
* every packet that passes the packet filter *and* is
|
|
* successfully copied to the ring buffer; "tp_drops" is
|
|
* incremented for every packet dropped because there's
|
|
* not enough free space in the ring buffer.
|
|
*
|
|
* When the statistics are returned for a PACKET_STATISTICS
|
|
* "getsockopt()" call, "tp_drops" is added to "tp_packets",
|
|
* so that "tp_packets" counts all packets handed to
|
|
* the PF_PACKET socket, including packets dropped because
|
|
* there wasn't room on the socket buffer - but not
|
|
* including packets that didn't pass the filter.
|
|
*
|
|
* In the BSD BPF, the count of received packets is
|
|
* incremented for every packet handed to BPF, regardless
|
|
* of whether it passed the filter.
|
|
*
|
|
* We can't make "pcap_stats()" work the same on both
|
|
* platforms, but the best approximation is to return
|
|
* "tp_packets" as the count of packets and "tp_drops"
|
|
* as the count of drops.
|
|
*
|
|
* Keep a running total because each call to
|
|
* getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, ....
|
|
* resets the counters to zero.
|
|
*/
|
|
handlep->stat.ps_recv += kstats.tp_packets;
|
|
handlep->stat.ps_drop += kstats.tp_drops;
|
|
*stats = handlep->stat;
|
|
return 0;
|
|
}
|
|
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE, errno,
|
|
"failed to get statistics from socket");
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* Description string for the "any" device.
|
|
*/
|
|
static const char any_descr[] = "Pseudo-device that captures on all interfaces";
|
|
|
|
/*
|
|
* A PF_PACKET socket can be bound to any network interface.
|
|
*/
|
|
static int
|
|
can_be_bound(const char *name _U_)
|
|
{
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* Get a socket to use with various interface ioctls.
|
|
*/
|
|
static int
|
|
get_if_ioctl_socket(void)
|
|
{
|
|
int fd;
|
|
|
|
/*
|
|
* This is a bit ugly.
|
|
*
|
|
* There isn't a socket type that's guaranteed to work.
|
|
*
|
|
* AF_NETLINK will work *if* you have Netlink configured into the
|
|
* kernel (can it be configured out if you have any networking
|
|
* support at all?) *and* if you're running a sufficiently recent
|
|
* kernel, but not all the kernels we support are sufficiently
|
|
* recent - that feature was introduced in Linux 4.6.
|
|
*
|
|
* AF_UNIX will work *if* you have UNIX-domain sockets configured
|
|
* into the kernel and *if* you're not on a system that doesn't
|
|
* allow them - some SELinux systems don't allow you create them.
|
|
* Most systems probably have them configured in, but not all systems
|
|
* have them configured in and allow them to be created.
|
|
*
|
|
* AF_INET will work *if* you have IPv4 configured into the kernel,
|
|
* but, apparently, some systems have network adapters but have
|
|
* kernels without IPv4 support.
|
|
*
|
|
* AF_INET6 will work *if* you have IPv6 configured into the
|
|
* kernel, but if you don't have AF_INET, you might not have
|
|
* AF_INET6, either (that is, independently on its own grounds).
|
|
*
|
|
* AF_PACKET would work, except that some of these calls should
|
|
* work even if you *don't* have capture permission (you should be
|
|
* able to enumerate interfaces and get information about them
|
|
* without capture permission; you shouldn't get a failure until
|
|
* you try pcap_activate()). (If you don't allow programs to
|
|
* get as much information as possible about interfaces if you
|
|
* don't have permission to capture, you run the risk of users
|
|
* asking "why isn't it showing XXX" - or, worse, if you don't
|
|
* show interfaces *at all* if you don't have permission to
|
|
* capture on them, "why do no interfaces show up?" - when the
|
|
* real problem is a permissions problem. Error reports of that
|
|
* type require a lot more back-and-forth to debug, as evidenced
|
|
* by many Wireshark bugs/mailing list questions/Q&A questions.)
|
|
*
|
|
* So:
|
|
*
|
|
* we first try an AF_NETLINK socket, where "try" includes
|
|
* "try to do a device ioctl on it", as, in the future, once
|
|
* pre-4.6 kernels are sufficiently rare, that will probably
|
|
* be the mechanism most likely to work;
|
|
*
|
|
* if that fails, we try an AF_UNIX socket, as that's less
|
|
* likely to be configured out on a networking-capable system
|
|
* than is IP;
|
|
*
|
|
* if that fails, we try an AF_INET6 socket;
|
|
*
|
|
* if that fails, we try an AF_INET socket.
|
|
*/
|
|
fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
|
|
if (fd != -1) {
|
|
/*
|
|
* OK, let's make sure we can do an SIOCGIFNAME
|
|
* ioctl.
|
|
*/
|
|
struct ifreq ifr;
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
if (ioctl(fd, SIOCGIFNAME, &ifr) == 0 ||
|
|
errno != EOPNOTSUPP) {
|
|
/*
|
|
* It succeeded, or failed for some reason
|
|
* other than "netlink sockets don't support
|
|
* device ioctls". Go with the AF_NETLINK
|
|
* socket.
|
|
*/
|
|
return (fd);
|
|
}
|
|
|
|
/*
|
|
* OK, that didn't work, so it's as bad as "netlink
|
|
* sockets aren't available". Close the socket and
|
|
* drive on.
|
|
*/
|
|
close(fd);
|
|
}
|
|
|
|
/*
|
|
* Now try an AF_UNIX socket.
|
|
*/
|
|
fd = socket(AF_UNIX, SOCK_RAW, 0);
|
|
if (fd != -1) {
|
|
/*
|
|
* OK, we got it!
|
|
*/
|
|
return (fd);
|
|
}
|
|
|
|
/*
|
|
* Now try an AF_INET6 socket.
|
|
*/
|
|
fd = socket(AF_INET6, SOCK_DGRAM, 0);
|
|
if (fd != -1) {
|
|
return (fd);
|
|
}
|
|
|
|
/*
|
|
* Now try an AF_INET socket.
|
|
*
|
|
* XXX - if that fails, is there anything else we should try?
|
|
* AF_CAN, for embedded systems in vehicles, in case they're
|
|
* built without Internet protocol support? Any other socket
|
|
* types popular in non-Internet embedded systems?
|
|
*/
|
|
return (socket(AF_INET, SOCK_DGRAM, 0));
|
|
}
|
|
|
|
/*
|
|
* Get additional flags for a device, using SIOCGIFMEDIA.
|
|
*/
|
|
static int
|
|
get_if_flags(const char *name, bpf_u_int32 *flags, char *errbuf)
|
|
{
|
|
int sock;
|
|
FILE *fh;
|
|
unsigned int arptype;
|
|
struct ifreq ifr;
|
|
struct ethtool_value info;
|
|
|
|
if (*flags & PCAP_IF_LOOPBACK) {
|
|
/*
|
|
* Loopback devices aren't wireless, and "connected"/
|
|
* "disconnected" doesn't apply to them.
|
|
*/
|
|
*flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
|
|
return 0;
|
|
}
|
|
|
|
sock = get_if_ioctl_socket();
|
|
if (sock == -1) {
|
|
pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE, errno,
|
|
"Can't create socket to get ethtool information for %s",
|
|
name);
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* OK, what type of network is this?
|
|
* In particular, is it wired or wireless?
|
|
*/
|
|
if (is_wifi(name)) {
|
|
/*
|
|
* Wi-Fi, hence wireless.
|
|
*/
|
|
*flags |= PCAP_IF_WIRELESS;
|
|
} else {
|
|
/*
|
|
* OK, what does /sys/class/net/{if_name}/type contain?
|
|
* (We don't use that for Wi-Fi, as it'll report
|
|
* "Ethernet", i.e. ARPHRD_ETHER, for non-monitor-
|
|
* mode devices.)
|
|
*/
|
|
char *pathstr;
|
|
|
|
if (asprintf(&pathstr, "/sys/class/net/%s/type", name) == -1) {
|
|
snprintf(errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: Can't generate path name string for /sys/class/net device",
|
|
name);
|
|
close(sock);
|
|
return -1;
|
|
}
|
|
fh = fopen(pathstr, "r");
|
|
if (fh != NULL) {
|
|
if (fscanf(fh, "%u", &arptype) == 1) {
|
|
/*
|
|
* OK, we got an ARPHRD_ type; what is it?
|
|
*/
|
|
switch (arptype) {
|
|
|
|
case ARPHRD_LOOPBACK:
|
|
/*
|
|
* These are types to which
|
|
* "connected" and "disconnected"
|
|
* don't apply, so don't bother
|
|
* asking about it.
|
|
*
|
|
* XXX - add other types?
|
|
*/
|
|
close(sock);
|
|
fclose(fh);
|
|
free(pathstr);
|
|
return 0;
|
|
|
|
case ARPHRD_IRDA:
|
|
case ARPHRD_IEEE80211:
|
|
case ARPHRD_IEEE80211_PRISM:
|
|
case ARPHRD_IEEE80211_RADIOTAP:
|
|
#ifdef ARPHRD_IEEE802154
|
|
case ARPHRD_IEEE802154:
|
|
#endif
|
|
#ifdef ARPHRD_IEEE802154_MONITOR
|
|
case ARPHRD_IEEE802154_MONITOR:
|
|
#endif
|
|
#ifdef ARPHRD_6LOWPAN
|
|
case ARPHRD_6LOWPAN:
|
|
#endif
|
|
/*
|
|
* Various wireless types.
|
|
*/
|
|
*flags |= PCAP_IF_WIRELESS;
|
|
break;
|
|
}
|
|
}
|
|
fclose(fh);
|
|
}
|
|
free(pathstr);
|
|
}
|
|
|
|
#ifdef ETHTOOL_GLINK
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
|
|
info.cmd = ETHTOOL_GLINK;
|
|
/*
|
|
* XXX - while Valgrind handles SIOCETHTOOL and knows that
|
|
* the ETHTOOL_GLINK command sets the .data member of the
|
|
* structure, Memory Sanitizer doesn't yet do so:
|
|
*
|
|
* https://bugs.llvm.org/show_bug.cgi?id=45814
|
|
*
|
|
* For now, we zero it out to squelch warnings; if the bug
|
|
* in question is fixed, we can remove this.
|
|
*/
|
|
info.data = 0;
|
|
ifr.ifr_data = (caddr_t)&info;
|
|
if (ioctl(sock, SIOCETHTOOL, &ifr) == -1) {
|
|
int save_errno = errno;
|
|
|
|
switch (save_errno) {
|
|
|
|
case EOPNOTSUPP:
|
|
case EINVAL:
|
|
/*
|
|
* OK, this OS version or driver doesn't support
|
|
* asking for this information.
|
|
* XXX - distinguish between "this doesn't
|
|
* support ethtool at all because it's not
|
|
* that type of device" vs. "this doesn't
|
|
* support ethtool even though it's that
|
|
* type of device", and return "unknown".
|
|
*/
|
|
*flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
|
|
close(sock);
|
|
return 0;
|
|
|
|
case ENODEV:
|
|
/*
|
|
* OK, no such device.
|
|
* The user will find that out when they try to
|
|
* activate the device; just say "OK" and
|
|
* don't set anything.
|
|
*/
|
|
close(sock);
|
|
return 0;
|
|
|
|
default:
|
|
/*
|
|
* Other error.
|
|
*/
|
|
pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
|
|
save_errno,
|
|
"%s: SIOCETHTOOL(ETHTOOL_GLINK) ioctl failed",
|
|
name);
|
|
close(sock);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Is it connected?
|
|
*/
|
|
if (info.data) {
|
|
/*
|
|
* It's connected.
|
|
*/
|
|
*flags |= PCAP_IF_CONNECTION_STATUS_CONNECTED;
|
|
} else {
|
|
/*
|
|
* It's disconnected.
|
|
*/
|
|
*flags |= PCAP_IF_CONNECTION_STATUS_DISCONNECTED;
|
|
}
|
|
#endif
|
|
|
|
close(sock);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
|
|
{
|
|
/*
|
|
* Get the list of regular interfaces first.
|
|
*/
|
|
if (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
|
|
get_if_flags) == -1)
|
|
return (-1); /* failure */
|
|
|
|
/*
|
|
* Add the "any" device.
|
|
* As it refers to all network devices, not to any particular
|
|
* network device, the notion of "connected" vs. "disconnected"
|
|
* doesn't apply.
|
|
*/
|
|
if (add_dev(devlistp, "any",
|
|
PCAP_IF_UP|PCAP_IF_RUNNING|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
|
|
any_descr, errbuf) == NULL)
|
|
return (-1);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Set direction flag: Which packets do we accept on a forwarding
|
|
* single device? IN, OUT or both?
|
|
*/
|
|
static int
|
|
pcap_setdirection_linux(pcap_t *handle, pcap_direction_t d)
|
|
{
|
|
/*
|
|
* It's guaranteed, at this point, that d is a valid
|
|
* direction value.
|
|
*/
|
|
handle->direction = d;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
is_wifi(const char *device)
|
|
{
|
|
char *pathstr;
|
|
struct stat statb;
|
|
|
|
/*
|
|
* See if there's a sysfs wireless directory for it.
|
|
* If so, it's a wireless interface.
|
|
*/
|
|
if (asprintf(&pathstr, "/sys/class/net/%s/wireless", device) == -1) {
|
|
/*
|
|
* Just give up here.
|
|
*/
|
|
return 0;
|
|
}
|
|
if (stat(pathstr, &statb) == 0) {
|
|
free(pathstr);
|
|
return 1;
|
|
}
|
|
free(pathstr);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Linux uses the ARP hardware type to identify the type of an
|
|
* interface. pcap uses the DLT_xxx constants for this. This
|
|
* function takes a pointer to a "pcap_t", and an ARPHRD_xxx
|
|
* constant, as arguments, and sets "handle->linktype" to the
|
|
* appropriate DLT_XXX constant and sets "handle->offset" to
|
|
* the appropriate value (to make "handle->offset" plus link-layer
|
|
* header length be a multiple of 4, so that the link-layer payload
|
|
* will be aligned on a 4-byte boundary when capturing packets).
|
|
* (If the offset isn't set here, it'll be 0; add code as appropriate
|
|
* for cases where it shouldn't be 0.)
|
|
*
|
|
* If "cooked_ok" is non-zero, we can use DLT_LINUX_SLL and capture
|
|
* in cooked mode; otherwise, we can't use cooked mode, so we have
|
|
* to pick some type that works in raw mode, or fail.
|
|
*
|
|
* Sets the link type to -1 if unable to map the type.
|
|
*/
|
|
static void map_arphrd_to_dlt(pcap_t *handle, int arptype,
|
|
const char *device, int cooked_ok)
|
|
{
|
|
static const char cdma_rmnet[] = "cdma_rmnet";
|
|
|
|
switch (arptype) {
|
|
|
|
case ARPHRD_ETHER:
|
|
/*
|
|
* For various annoying reasons having to do with DHCP
|
|
* software, some versions of Android give the mobile-
|
|
* phone-network interface an ARPHRD_ value of
|
|
* ARPHRD_ETHER, even though the packets supplied by
|
|
* that interface have no link-layer header, and begin
|
|
* with an IP header, so that the ARPHRD_ value should
|
|
* be ARPHRD_NONE.
|
|
*
|
|
* Detect those devices by checking the device name, and
|
|
* use DLT_RAW for them.
|
|
*/
|
|
if (strncmp(device, cdma_rmnet, sizeof cdma_rmnet - 1) == 0) {
|
|
handle->linktype = DLT_RAW;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Is this a real Ethernet device? If so, give it a
|
|
* link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
|
|
* that an application can let you choose it, in case you're
|
|
* capturing DOCSIS traffic that a Cisco Cable Modem
|
|
* Termination System is putting out onto an Ethernet (it
|
|
* doesn't put an Ethernet header onto the wire, it puts raw
|
|
* DOCSIS frames out on the wire inside the low-level
|
|
* Ethernet framing).
|
|
*
|
|
* XXX - are there any other sorts of "fake Ethernet" that
|
|
* have ARPHRD_ETHER but that shouldn't offer DLT_DOCSIS as
|
|
* a Cisco CMTS won't put traffic onto it or get traffic
|
|
* bridged onto it? ISDN is handled in "setup_socket()",
|
|
* as we fall back on cooked mode there, and we use
|
|
* is_wifi() to check for 802.11 devices; are there any
|
|
* others?
|
|
*/
|
|
if (!is_wifi(device)) {
|
|
int ret;
|
|
|
|
/*
|
|
* This is not a Wi-Fi device but it could be
|
|
* a DSA master/management network device.
|
|
*/
|
|
ret = iface_dsa_get_proto_info(device, handle);
|
|
if (ret < 0)
|
|
return;
|
|
|
|
if (ret == 1) {
|
|
/*
|
|
* This is a DSA master/management network
|
|
* device linktype is already set by
|
|
* iface_dsa_get_proto_info() set an
|
|
* appropriate offset here.
|
|
*/
|
|
handle->offset = 2;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* It's not a Wi-Fi device; offer DOCSIS.
|
|
*/
|
|
handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
|
|
/*
|
|
* If that fails, just leave the list empty.
|
|
*/
|
|
if (handle->dlt_list != NULL) {
|
|
handle->dlt_list[0] = DLT_EN10MB;
|
|
handle->dlt_list[1] = DLT_DOCSIS;
|
|
handle->dlt_count = 2;
|
|
}
|
|
}
|
|
/* FALLTHROUGH */
|
|
|
|
case ARPHRD_METRICOM:
|
|
case ARPHRD_LOOPBACK:
|
|
handle->linktype = DLT_EN10MB;
|
|
handle->offset = 2;
|
|
break;
|
|
|
|
case ARPHRD_EETHER:
|
|
handle->linktype = DLT_EN3MB;
|
|
break;
|
|
|
|
case ARPHRD_AX25:
|
|
handle->linktype = DLT_AX25_KISS;
|
|
break;
|
|
|
|
case ARPHRD_PRONET:
|
|
handle->linktype = DLT_PRONET;
|
|
break;
|
|
|
|
case ARPHRD_CHAOS:
|
|
handle->linktype = DLT_CHAOS;
|
|
break;
|
|
#ifndef ARPHRD_CAN
|
|
#define ARPHRD_CAN 280
|
|
#endif
|
|
case ARPHRD_CAN:
|
|
handle->linktype = DLT_CAN_SOCKETCAN;
|
|
break;
|
|
|
|
#ifndef ARPHRD_IEEE802_TR
|
|
#define ARPHRD_IEEE802_TR 800 /* From Linux 2.4 */
|
|
#endif
|
|
case ARPHRD_IEEE802_TR:
|
|
case ARPHRD_IEEE802:
|
|
handle->linktype = DLT_IEEE802;
|
|
handle->offset = 2;
|
|
break;
|
|
|
|
case ARPHRD_ARCNET:
|
|
handle->linktype = DLT_ARCNET_LINUX;
|
|
break;
|
|
|
|
#ifndef ARPHRD_FDDI /* From Linux 2.2.13 */
|
|
#define ARPHRD_FDDI 774
|
|
#endif
|
|
case ARPHRD_FDDI:
|
|
handle->linktype = DLT_FDDI;
|
|
handle->offset = 3;
|
|
break;
|
|
|
|
#ifndef ARPHRD_ATM /* FIXME: How to #include this? */
|
|
#define ARPHRD_ATM 19
|
|
#endif
|
|
case ARPHRD_ATM:
|
|
/*
|
|
* The Classical IP implementation in ATM for Linux
|
|
* supports both what RFC 1483 calls "LLC Encapsulation",
|
|
* in which each packet has an LLC header, possibly
|
|
* with a SNAP header as well, prepended to it, and
|
|
* what RFC 1483 calls "VC Based Multiplexing", in which
|
|
* different virtual circuits carry different network
|
|
* layer protocols, and no header is prepended to packets.
|
|
*
|
|
* They both have an ARPHRD_ type of ARPHRD_ATM, so
|
|
* you can't use the ARPHRD_ type to find out whether
|
|
* captured packets will have an LLC header, and,
|
|
* while there's a socket ioctl to *set* the encapsulation
|
|
* type, there's no ioctl to *get* the encapsulation type.
|
|
*
|
|
* This means that
|
|
*
|
|
* programs that dissect Linux Classical IP frames
|
|
* would have to check for an LLC header and,
|
|
* depending on whether they see one or not, dissect
|
|
* the frame as LLC-encapsulated or as raw IP (I
|
|
* don't know whether there's any traffic other than
|
|
* IP that would show up on the socket, or whether
|
|
* there's any support for IPv6 in the Linux
|
|
* Classical IP code);
|
|
*
|
|
* filter expressions would have to compile into
|
|
* code that checks for an LLC header and does
|
|
* the right thing.
|
|
*
|
|
* Both of those are a nuisance - and, at least on systems
|
|
* that support PF_PACKET sockets, we don't have to put
|
|
* up with those nuisances; instead, we can just capture
|
|
* in cooked mode. That's what we'll do, if we can.
|
|
* Otherwise, we'll just fail.
|
|
*/
|
|
if (cooked_ok)
|
|
handle->linktype = DLT_LINUX_SLL;
|
|
else
|
|
handle->linktype = -1;
|
|
break;
|
|
|
|
#ifndef ARPHRD_IEEE80211 /* From Linux 2.4.6 */
|
|
#define ARPHRD_IEEE80211 801
|
|
#endif
|
|
case ARPHRD_IEEE80211:
|
|
handle->linktype = DLT_IEEE802_11;
|
|
break;
|
|
|
|
#ifndef ARPHRD_IEEE80211_PRISM /* From Linux 2.4.18 */
|
|
#define ARPHRD_IEEE80211_PRISM 802
|
|
#endif
|
|
case ARPHRD_IEEE80211_PRISM:
|
|
handle->linktype = DLT_PRISM_HEADER;
|
|
break;
|
|
|
|
#ifndef ARPHRD_IEEE80211_RADIOTAP /* new */
|
|
#define ARPHRD_IEEE80211_RADIOTAP 803
|
|
#endif
|
|
case ARPHRD_IEEE80211_RADIOTAP:
|
|
handle->linktype = DLT_IEEE802_11_RADIO;
|
|
break;
|
|
|
|
case ARPHRD_PPP:
|
|
/*
|
|
* Some PPP code in the kernel supplies no link-layer
|
|
* header whatsoever to PF_PACKET sockets; other PPP
|
|
* code supplies PPP link-layer headers ("syncppp.c");
|
|
* some PPP code might supply random link-layer
|
|
* headers (PPP over ISDN - there's code in Ethereal,
|
|
* for example, to cope with PPP-over-ISDN captures
|
|
* with which the Ethereal developers have had to cope,
|
|
* heuristically trying to determine which of the
|
|
* oddball link-layer headers particular packets have).
|
|
*
|
|
* As such, we just punt, and run all PPP interfaces
|
|
* in cooked mode, if we can; otherwise, we just treat
|
|
* it as DLT_RAW, for now - if somebody needs to capture,
|
|
* on a 2.0[.x] kernel, on PPP devices that supply a
|
|
* link-layer header, they'll have to add code here to
|
|
* map to the appropriate DLT_ type (possibly adding a
|
|
* new DLT_ type, if necessary).
|
|
*/
|
|
if (cooked_ok)
|
|
handle->linktype = DLT_LINUX_SLL;
|
|
else {
|
|
/*
|
|
* XXX - handle ISDN types here? We can't fall
|
|
* back on cooked sockets, so we'd have to
|
|
* figure out from the device name what type of
|
|
* link-layer encapsulation it's using, and map
|
|
* that to an appropriate DLT_ value, meaning
|
|
* we'd map "isdnN" devices to DLT_RAW (they
|
|
* supply raw IP packets with no link-layer
|
|
* header) and "isdY" devices to a new DLT_I4L_IP
|
|
* type that has only an Ethernet packet type as
|
|
* a link-layer header.
|
|
*
|
|
* But sometimes we seem to get random crap
|
|
* in the link-layer header when capturing on
|
|
* ISDN devices....
|
|
*/
|
|
handle->linktype = DLT_RAW;
|
|
}
|
|
break;
|
|
|
|
#ifndef ARPHRD_CISCO
|
|
#define ARPHRD_CISCO 513 /* previously ARPHRD_HDLC */
|
|
#endif
|
|
case ARPHRD_CISCO:
|
|
handle->linktype = DLT_C_HDLC;
|
|
break;
|
|
|
|
/* Not sure if this is correct for all tunnels, but it
|
|
* works for CIPE */
|
|
case ARPHRD_TUNNEL:
|
|
#ifndef ARPHRD_SIT
|
|
#define ARPHRD_SIT 776 /* From Linux 2.2.13 */
|
|
#endif
|
|
case ARPHRD_SIT:
|
|
case ARPHRD_CSLIP:
|
|
case ARPHRD_SLIP6:
|
|
case ARPHRD_CSLIP6:
|
|
case ARPHRD_ADAPT:
|
|
case ARPHRD_SLIP:
|
|
#ifndef ARPHRD_RAWHDLC
|
|
#define ARPHRD_RAWHDLC 518
|
|
#endif
|
|
case ARPHRD_RAWHDLC:
|
|
#ifndef ARPHRD_DLCI
|
|
#define ARPHRD_DLCI 15
|
|
#endif
|
|
case ARPHRD_DLCI:
|
|
/*
|
|
* XXX - should some of those be mapped to DLT_LINUX_SLL
|
|
* instead? Should we just map all of them to DLT_LINUX_SLL?
|
|
*/
|
|
handle->linktype = DLT_RAW;
|
|
break;
|
|
|
|
#ifndef ARPHRD_FRAD
|
|
#define ARPHRD_FRAD 770
|
|
#endif
|
|
case ARPHRD_FRAD:
|
|
handle->linktype = DLT_FRELAY;
|
|
break;
|
|
|
|
case ARPHRD_LOCALTLK:
|
|
handle->linktype = DLT_LTALK;
|
|
break;
|
|
|
|
case 18:
|
|
/*
|
|
* RFC 4338 defines an encapsulation for IP and ARP
|
|
* packets that's compatible with the RFC 2625
|
|
* encapsulation, but that uses a different ARP
|
|
* hardware type and hardware addresses. That
|
|
* ARP hardware type is 18; Linux doesn't define
|
|
* any ARPHRD_ value as 18, but if it ever officially
|
|
* supports RFC 4338-style IP-over-FC, it should define
|
|
* one.
|
|
*
|
|
* For now, we map it to DLT_IP_OVER_FC, in the hopes
|
|
* that this will encourage its use in the future,
|
|
* should Linux ever officially support RFC 4338-style
|
|
* IP-over-FC.
|
|
*/
|
|
handle->linktype = DLT_IP_OVER_FC;
|
|
break;
|
|
|
|
#ifndef ARPHRD_FCPP
|
|
#define ARPHRD_FCPP 784
|
|
#endif
|
|
case ARPHRD_FCPP:
|
|
#ifndef ARPHRD_FCAL
|
|
#define ARPHRD_FCAL 785
|
|
#endif
|
|
case ARPHRD_FCAL:
|
|
#ifndef ARPHRD_FCPL
|
|
#define ARPHRD_FCPL 786
|
|
#endif
|
|
case ARPHRD_FCPL:
|
|
#ifndef ARPHRD_FCFABRIC
|
|
#define ARPHRD_FCFABRIC 787
|
|
#endif
|
|
case ARPHRD_FCFABRIC:
|
|
/*
|
|
* Back in 2002, Donald Lee at Cray wanted a DLT_ for
|
|
* IP-over-FC:
|
|
*
|
|
* https://www.mail-archive.com/tcpdump-workers@sandelman.ottawa.on.ca/msg01043.html
|
|
*
|
|
* and one was assigned.
|
|
*
|
|
* In a later private discussion (spun off from a message
|
|
* on the ethereal-users list) on how to get that DLT_
|
|
* value in libpcap on Linux, I ended up deciding that
|
|
* the best thing to do would be to have him tweak the
|
|
* driver to set the ARPHRD_ value to some ARPHRD_FCxx
|
|
* type, and map all those types to DLT_IP_OVER_FC:
|
|
*
|
|
* I've checked into the libpcap and tcpdump CVS tree
|
|
* support for DLT_IP_OVER_FC. In order to use that,
|
|
* you'd have to modify your modified driver to return
|
|
* one of the ARPHRD_FCxxx types, in "fcLINUXfcp.c" -
|
|
* change it to set "dev->type" to ARPHRD_FCFABRIC, for
|
|
* example (the exact value doesn't matter, it can be
|
|
* any of ARPHRD_FCPP, ARPHRD_FCAL, ARPHRD_FCPL, or
|
|
* ARPHRD_FCFABRIC).
|
|
*
|
|
* 11 years later, Christian Svensson wanted to map
|
|
* various ARPHRD_ values to DLT_FC_2 and
|
|
* DLT_FC_2_WITH_FRAME_DELIMS for raw Fibre Channel
|
|
* frames:
|
|
*
|
|
* https://github.com/mcr/libpcap/pull/29
|
|
*
|
|
* There doesn't seem to be any network drivers that uses
|
|
* any of the ARPHRD_FC* values for IP-over-FC, and
|
|
* it's not exactly clear what the "Dummy types for non
|
|
* ARP hardware" are supposed to mean (link-layer
|
|
* header type? Physical network type?), so it's
|
|
* not exactly clear why the ARPHRD_FC* types exist
|
|
* in the first place.
|
|
*
|
|
* For now, we map them to DLT_FC_2, and provide an
|
|
* option of DLT_FC_2_WITH_FRAME_DELIMS, as well as
|
|
* DLT_IP_OVER_FC just in case there's some old
|
|
* driver out there that uses one of those types for
|
|
* IP-over-FC on which somebody wants to capture
|
|
* packets.
|
|
*/
|
|
handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 3);
|
|
/*
|
|
* If that fails, just leave the list empty.
|
|
*/
|
|
if (handle->dlt_list != NULL) {
|
|
handle->dlt_list[0] = DLT_FC_2;
|
|
handle->dlt_list[1] = DLT_FC_2_WITH_FRAME_DELIMS;
|
|
handle->dlt_list[2] = DLT_IP_OVER_FC;
|
|
handle->dlt_count = 3;
|
|
}
|
|
handle->linktype = DLT_FC_2;
|
|
break;
|
|
|
|
#ifndef ARPHRD_IRDA
|
|
#define ARPHRD_IRDA 783
|
|
#endif
|
|
case ARPHRD_IRDA:
|
|
/* Don't expect IP packet out of this interfaces... */
|
|
handle->linktype = DLT_LINUX_IRDA;
|
|
/* We need to save packet direction for IrDA decoding,
|
|
* so let's use "Linux-cooked" mode. Jean II
|
|
*
|
|
* XXX - this is handled in setup_socket(). */
|
|
/* handlep->cooked = 1; */
|
|
break;
|
|
|
|
/* ARPHRD_LAPD is unofficial and randomly allocated, if reallocation
|
|
* is needed, please report it to <daniele@orlandi.com> */
|
|
#ifndef ARPHRD_LAPD
|
|
#define ARPHRD_LAPD 8445
|
|
#endif
|
|
case ARPHRD_LAPD:
|
|
/* Don't expect IP packet out of this interfaces... */
|
|
handle->linktype = DLT_LINUX_LAPD;
|
|
break;
|
|
|
|
#ifndef ARPHRD_NONE
|
|
#define ARPHRD_NONE 0xFFFE
|
|
#endif
|
|
case ARPHRD_NONE:
|
|
/*
|
|
* No link-layer header; packets are just IP
|
|
* packets, so use DLT_RAW.
|
|
*/
|
|
handle->linktype = DLT_RAW;
|
|
break;
|
|
|
|
#ifndef ARPHRD_IEEE802154
|
|
#define ARPHRD_IEEE802154 804
|
|
#endif
|
|
case ARPHRD_IEEE802154:
|
|
handle->linktype = DLT_IEEE802_15_4_NOFCS;
|
|
break;
|
|
|
|
#ifndef ARPHRD_NETLINK
|
|
#define ARPHRD_NETLINK 824
|
|
#endif
|
|
case ARPHRD_NETLINK:
|
|
handle->linktype = DLT_NETLINK;
|
|
/*
|
|
* We need to use cooked mode, so that in sll_protocol we
|
|
* pick up the netlink protocol type such as NETLINK_ROUTE,
|
|
* NETLINK_GENERIC, NETLINK_FIB_LOOKUP, etc.
|
|
*
|
|
* XXX - this is handled in setup_socket().
|
|
*/
|
|
/* handlep->cooked = 1; */
|
|
break;
|
|
|
|
#ifndef ARPHRD_VSOCKMON
|
|
#define ARPHRD_VSOCKMON 826
|
|
#endif
|
|
case ARPHRD_VSOCKMON:
|
|
handle->linktype = DLT_VSOCK;
|
|
break;
|
|
|
|
default:
|
|
handle->linktype = -1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void
|
|
set_dlt_list_cooked(pcap_t *handle)
|
|
{
|
|
/*
|
|
* Support both DLT_LINUX_SLL and DLT_LINUX_SLL2.
|
|
*/
|
|
handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
|
|
|
|
/*
|
|
* If that failed, just leave the list empty.
|
|
*/
|
|
if (handle->dlt_list != NULL) {
|
|
handle->dlt_list[0] = DLT_LINUX_SLL;
|
|
handle->dlt_list[1] = DLT_LINUX_SLL2;
|
|
handle->dlt_count = 2;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Try to set up a PF_PACKET socket.
|
|
* Returns 0 on success and a PCAP_ERROR_ value on failure.
|
|
*/
|
|
static int
|
|
setup_socket(pcap_t *handle, int is_any_device)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
const char *device = handle->opt.device;
|
|
int status = 0;
|
|
int sock_fd, arptype;
|
|
int val;
|
|
int err = 0;
|
|
struct packet_mreq mr;
|
|
#if defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT)
|
|
int bpf_extensions;
|
|
socklen_t len = sizeof(bpf_extensions);
|
|
#endif
|
|
|
|
/*
|
|
* Open a socket with protocol family packet. If cooked is true,
|
|
* we open a SOCK_DGRAM socket for the cooked interface, otherwise
|
|
* we open a SOCK_RAW socket for the raw interface.
|
|
*
|
|
* The protocol is set to 0. This means we will receive no
|
|
* packets until we "bind" the socket with a non-zero
|
|
* protocol. This allows us to setup the ring buffers without
|
|
* dropping any packets.
|
|
*/
|
|
sock_fd = is_any_device ?
|
|
socket(PF_PACKET, SOCK_DGRAM, 0) :
|
|
socket(PF_PACKET, SOCK_RAW, 0);
|
|
|
|
if (sock_fd == -1) {
|
|
if (errno == EPERM || errno == EACCES) {
|
|
/*
|
|
* You don't have permission to open the
|
|
* socket.
|
|
*/
|
|
status = PCAP_ERROR_PERM_DENIED;
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Attempt to create packet socket failed - CAP_NET_RAW may be required");
|
|
} else {
|
|
/*
|
|
* Other error.
|
|
*/
|
|
status = PCAP_ERROR;
|
|
}
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "socket");
|
|
return status;
|
|
}
|
|
|
|
/*
|
|
* Get the interface index of the loopback device.
|
|
* If the attempt fails, don't fail, just set the
|
|
* "handlep->lo_ifindex" to -1.
|
|
*
|
|
* XXX - can there be more than one device that loops
|
|
* packets back, i.e. devices other than "lo"? If so,
|
|
* we'd need to find them all, and have an array of
|
|
* indices for them, and check all of them in
|
|
* "pcap_read_packet()".
|
|
*/
|
|
handlep->lo_ifindex = iface_get_id(sock_fd, "lo", handle->errbuf);
|
|
|
|
/*
|
|
* Default value for offset to align link-layer payload
|
|
* on a 4-byte boundary.
|
|
*/
|
|
handle->offset = 0;
|
|
|
|
/*
|
|
* What kind of frames do we have to deal with? Fall back
|
|
* to cooked mode if we have an unknown interface type
|
|
* or a type we know doesn't work well in raw mode.
|
|
*/
|
|
if (!is_any_device) {
|
|
/* Assume for now we don't need cooked mode. */
|
|
handlep->cooked = 0;
|
|
|
|
if (handle->opt.rfmon) {
|
|
/*
|
|
* We were asked to turn on monitor mode.
|
|
* Do so before we get the link-layer type,
|
|
* because entering monitor mode could change
|
|
* the link-layer type.
|
|
*/
|
|
err = enter_rfmon_mode(handle, sock_fd, device);
|
|
if (err < 0) {
|
|
/* Hard failure */
|
|
close(sock_fd);
|
|
return err;
|
|
}
|
|
if (err == 0) {
|
|
/*
|
|
* Nothing worked for turning monitor mode
|
|
* on.
|
|
*/
|
|
close(sock_fd);
|
|
return PCAP_ERROR_RFMON_NOTSUP;
|
|
}
|
|
|
|
/*
|
|
* Either monitor mode has been turned on for
|
|
* the device, or we've been given a different
|
|
* device to open for monitor mode. If we've
|
|
* been given a different device, use it.
|
|
*/
|
|
if (handlep->mondevice != NULL)
|
|
device = handlep->mondevice;
|
|
}
|
|
arptype = iface_get_arptype(sock_fd, device, handle->errbuf);
|
|
if (arptype < 0) {
|
|
close(sock_fd);
|
|
return arptype;
|
|
}
|
|
map_arphrd_to_dlt(handle, arptype, device, 1);
|
|
if (handle->linktype == -1 ||
|
|
handle->linktype == DLT_LINUX_SLL ||
|
|
handle->linktype == DLT_LINUX_IRDA ||
|
|
handle->linktype == DLT_LINUX_LAPD ||
|
|
handle->linktype == DLT_NETLINK ||
|
|
(handle->linktype == DLT_EN10MB &&
|
|
(strncmp("isdn", device, 4) == 0 ||
|
|
strncmp("isdY", device, 4) == 0))) {
|
|
/*
|
|
* Unknown interface type (-1), or a
|
|
* device we explicitly chose to run
|
|
* in cooked mode (e.g., PPP devices),
|
|
* or an ISDN device (whose link-layer
|
|
* type we can only determine by using
|
|
* APIs that may be different on different
|
|
* kernels) - reopen in cooked mode.
|
|
*
|
|
* If the type is unknown, return a warning;
|
|
* map_arphrd_to_dlt() has already set the
|
|
* warning message.
|
|
*/
|
|
if (close(sock_fd) == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno, "close");
|
|
return PCAP_ERROR;
|
|
}
|
|
sock_fd = socket(PF_PACKET, SOCK_DGRAM, 0);
|
|
if (sock_fd < 0) {
|
|
/*
|
|
* Fatal error. We treat this as
|
|
* a generic error; we already know
|
|
* that we were able to open a
|
|
* PF_PACKET/SOCK_RAW socket, so
|
|
* any failure is a "this shouldn't
|
|
* happen" case.
|
|
*/
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno, "socket");
|
|
return PCAP_ERROR;
|
|
}
|
|
handlep->cooked = 1;
|
|
|
|
/*
|
|
* Get rid of any link-layer type list
|
|
* we allocated - this only supports cooked
|
|
* capture.
|
|
*/
|
|
if (handle->dlt_list != NULL) {
|
|
free(handle->dlt_list);
|
|
handle->dlt_list = NULL;
|
|
handle->dlt_count = 0;
|
|
set_dlt_list_cooked(handle);
|
|
}
|
|
|
|
if (handle->linktype == -1) {
|
|
/*
|
|
* Warn that we're falling back on
|
|
* cooked mode; we may want to
|
|
* update "map_arphrd_to_dlt()"
|
|
* to handle the new type.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"arptype %d not "
|
|
"supported by libpcap - "
|
|
"falling back to cooked "
|
|
"socket",
|
|
arptype);
|
|
}
|
|
|
|
/*
|
|
* IrDA capture is not a real "cooked" capture,
|
|
* it's IrLAP frames, not IP packets. The
|
|
* same applies to LAPD capture.
|
|
*/
|
|
if (handle->linktype != DLT_LINUX_IRDA &&
|
|
handle->linktype != DLT_LINUX_LAPD &&
|
|
handle->linktype != DLT_NETLINK)
|
|
handle->linktype = DLT_LINUX_SLL;
|
|
if (handle->linktype == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"unknown arptype %d, defaulting to cooked mode",
|
|
arptype);
|
|
status = PCAP_WARNING;
|
|
}
|
|
}
|
|
|
|
handlep->ifindex = iface_get_id(sock_fd, device,
|
|
handle->errbuf);
|
|
if (handlep->ifindex == -1) {
|
|
close(sock_fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
if ((err = iface_bind(sock_fd, handlep->ifindex,
|
|
handle->errbuf, 0)) != 0) {
|
|
close(sock_fd);
|
|
return err;
|
|
}
|
|
} else {
|
|
/*
|
|
* The "any" device.
|
|
*/
|
|
if (handle->opt.rfmon) {
|
|
/*
|
|
* It doesn't support monitor mode.
|
|
*/
|
|
close(sock_fd);
|
|
return PCAP_ERROR_RFMON_NOTSUP;
|
|
}
|
|
|
|
/*
|
|
* It uses cooked mode.
|
|
*/
|
|
handlep->cooked = 1;
|
|
handle->linktype = DLT_LINUX_SLL;
|
|
handle->dlt_list = NULL;
|
|
handle->dlt_count = 0;
|
|
set_dlt_list_cooked(handle);
|
|
|
|
/*
|
|
* We're not bound to a device.
|
|
* For now, we're using this as an indication
|
|
* that we can't transmit; stop doing that only
|
|
* if we figure out how to transmit in cooked
|
|
* mode.
|
|
*/
|
|
handlep->ifindex = -1;
|
|
}
|
|
|
|
/*
|
|
* Select promiscuous mode on if "promisc" is set.
|
|
*
|
|
* Do not turn allmulti mode on if we don't select
|
|
* promiscuous mode - on some devices (e.g., Orinoco
|
|
* wireless interfaces), allmulti mode isn't supported
|
|
* and the driver implements it by turning promiscuous
|
|
* mode on, and that screws up the operation of the
|
|
* card as a normal networking interface, and on no
|
|
* other platform I know of does starting a non-
|
|
* promiscuous capture affect which multicast packets
|
|
* are received by the interface.
|
|
*/
|
|
|
|
/*
|
|
* Hmm, how can we set promiscuous mode on all interfaces?
|
|
* I am not sure if that is possible at all. For now, we
|
|
* silently ignore attempts to turn promiscuous mode on
|
|
* for the "any" device (so you don't have to explicitly
|
|
* disable it in programs such as tcpdump).
|
|
*/
|
|
|
|
if (!is_any_device && handle->opt.promisc) {
|
|
memset(&mr, 0, sizeof(mr));
|
|
mr.mr_ifindex = handlep->ifindex;
|
|
mr.mr_type = PACKET_MR_PROMISC;
|
|
if (setsockopt(sock_fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP,
|
|
&mr, sizeof(mr)) == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno, "setsockopt (PACKET_ADD_MEMBERSHIP)");
|
|
close(sock_fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Enable auxiliary data and reserve room for reconstructing
|
|
* VLAN headers.
|
|
*
|
|
* XXX - is enabling auxiliary data necessary, now that we
|
|
* only support memory-mapped capture? The kernel's memory-mapped
|
|
* capture code doesn't seem to check whether auxiliary data
|
|
* is enabled, it seems to provide it whether it is or not.
|
|
*/
|
|
val = 1;
|
|
if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val,
|
|
sizeof(val)) == -1 && errno != ENOPROTOOPT) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "setsockopt (PACKET_AUXDATA)");
|
|
close(sock_fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
handle->offset += VLAN_TAG_LEN;
|
|
|
|
/*
|
|
* If we're in cooked mode, make the snapshot length
|
|
* large enough to hold a "cooked mode" header plus
|
|
* 1 byte of packet data (so we don't pass a byte
|
|
* count of 0 to "recvfrom()").
|
|
* XXX - we don't know whether this will be DLT_LINUX_SLL
|
|
* or DLT_LINUX_SLL2, so make sure it's big enough for
|
|
* a DLT_LINUX_SLL2 "cooked mode" header; a snapshot length
|
|
* that small is silly anyway.
|
|
*/
|
|
if (handlep->cooked) {
|
|
if (handle->snapshot < SLL2_HDR_LEN + 1)
|
|
handle->snapshot = SLL2_HDR_LEN + 1;
|
|
}
|
|
handle->bufsize = handle->snapshot;
|
|
|
|
/*
|
|
* Set the offset at which to insert VLAN tags.
|
|
*/
|
|
set_vlan_offset(handle);
|
|
|
|
if (handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO) {
|
|
int nsec_tstamps = 1;
|
|
|
|
if (setsockopt(sock_fd, SOL_SOCKET, SO_TIMESTAMPNS, &nsec_tstamps, sizeof(nsec_tstamps)) < 0) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "setsockopt: unable to set SO_TIMESTAMPNS");
|
|
close(sock_fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We've succeeded. Save the socket FD in the pcap structure.
|
|
*/
|
|
handle->fd = sock_fd;
|
|
|
|
#if defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT)
|
|
/*
|
|
* Can we generate special code for VLAN checks?
|
|
* (XXX - what if we need the special code but it's not supported
|
|
* by the OS? Is that possible?)
|
|
*/
|
|
if (getsockopt(sock_fd, SOL_SOCKET, SO_BPF_EXTENSIONS,
|
|
&bpf_extensions, &len) == 0) {
|
|
if (bpf_extensions >= SKF_AD_VLAN_TAG_PRESENT) {
|
|
/*
|
|
* Yes, we can. Request that we do so.
|
|
*/
|
|
handle->bpf_codegen_flags |= BPF_SPECIAL_VLAN_HANDLING;
|
|
}
|
|
}
|
|
#endif /* defined(SO_BPF_EXTENSIONS) && defined(SKF_AD_VLAN_TAG_PRESENT) */
|
|
|
|
return status;
|
|
}
|
|
|
|
/*
|
|
* Attempt to setup memory-mapped access.
|
|
*
|
|
* On success, returns 1, and sets *status to 0 if there are no warnings
|
|
* or to a PCAP_WARNING_ code if there is a warning.
|
|
*
|
|
* On error, returns -1, and sets *status to the appropriate error code;
|
|
* if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
|
|
*/
|
|
static int
|
|
setup_mmapped(pcap_t *handle, int *status)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
int ret;
|
|
|
|
/*
|
|
* Attempt to allocate a buffer to hold the contents of one
|
|
* packet, for use by the oneshot callback.
|
|
*/
|
|
handlep->oneshot_buffer = malloc(handle->snapshot);
|
|
if (handlep->oneshot_buffer == NULL) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "can't allocate oneshot buffer");
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
|
|
if (handle->opt.buffer_size == 0) {
|
|
/* by default request 2M for the ring buffer */
|
|
handle->opt.buffer_size = 2*1024*1024;
|
|
}
|
|
ret = prepare_tpacket_socket(handle);
|
|
if (ret == -1) {
|
|
free(handlep->oneshot_buffer);
|
|
handlep->oneshot_buffer = NULL;
|
|
*status = PCAP_ERROR;
|
|
return ret;
|
|
}
|
|
ret = create_ring(handle, status);
|
|
if (ret == -1) {
|
|
/*
|
|
* Error attempting to enable memory-mapped capture;
|
|
* fail. create_ring() has set *status.
|
|
*/
|
|
free(handlep->oneshot_buffer);
|
|
handlep->oneshot_buffer = NULL;
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* Success. *status has been set either to 0 if there are no
|
|
* warnings or to a PCAP_WARNING_ value if there is a warning.
|
|
*
|
|
* handle->offset is used to get the current position into the rx ring.
|
|
* handle->cc is used to store the ring size.
|
|
*/
|
|
|
|
/*
|
|
* Set the timeout to use in poll() before returning.
|
|
*/
|
|
set_poll_timeout(handlep);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Attempt to set the socket to the specified version of the memory-mapped
|
|
* header.
|
|
*
|
|
* Return 0 if we succeed; return 1 if we fail because that version isn't
|
|
* supported; return -1 on any other error, and set handle->errbuf.
|
|
*/
|
|
static int
|
|
init_tpacket(pcap_t *handle, int version, const char *version_str)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
int val = version;
|
|
socklen_t len = sizeof(val);
|
|
|
|
/*
|
|
* Probe whether kernel supports the specified TPACKET version;
|
|
* this also gets the length of the header for that version.
|
|
*
|
|
* This socket option was introduced in 2.6.27, which was
|
|
* also the first release with TPACKET_V2 support.
|
|
*/
|
|
if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) {
|
|
if (errno == EINVAL) {
|
|
/*
|
|
* EINVAL means this specific version of TPACKET
|
|
* is not supported. Tell the caller they can try
|
|
* with a different one; if they've run out of
|
|
* others to try, let them set the error message
|
|
* appropriately.
|
|
*/
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* All other errors are fatal.
|
|
*/
|
|
if (errno == ENOPROTOOPT) {
|
|
/*
|
|
* PACKET_HDRLEN isn't supported, which means
|
|
* that memory-mapped capture isn't supported.
|
|
* Indicate that in the message.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Kernel doesn't support memory-mapped capture; a 2.6.27 or later 2.x kernel is required, with CONFIG_PACKET_MMAP specified for 2.x kernels");
|
|
} else {
|
|
/*
|
|
* Some unexpected error.
|
|
*/
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "can't get %s header len on packet socket",
|
|
version_str);
|
|
}
|
|
return -1;
|
|
}
|
|
handlep->tp_hdrlen = val;
|
|
|
|
val = version;
|
|
if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val,
|
|
sizeof(val)) < 0) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "can't activate %s on packet socket", version_str);
|
|
return -1;
|
|
}
|
|
handlep->tp_version = version;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Attempt to set the socket to version 3 of the memory-mapped header and,
|
|
* if that fails because version 3 isn't supported, attempt to fall
|
|
* back to version 2. If version 2 isn't supported, just fail.
|
|
*
|
|
* Return 0 if we succeed and -1 on any other error, and set handle->errbuf.
|
|
*/
|
|
static int
|
|
prepare_tpacket_socket(pcap_t *handle)
|
|
{
|
|
int ret;
|
|
|
|
#ifdef HAVE_TPACKET3
|
|
/*
|
|
* Try setting the version to TPACKET_V3.
|
|
*
|
|
* The only mode in which buffering is done on PF_PACKET
|
|
* sockets, so that packets might not be delivered
|
|
* immediately, is TPACKET_V3 mode.
|
|
*
|
|
* The buffering cannot be disabled in that mode, so
|
|
* if the user has requested immediate mode, we don't
|
|
* use TPACKET_V3.
|
|
*/
|
|
if (!handle->opt.immediate) {
|
|
ret = init_tpacket(handle, TPACKET_V3, "TPACKET_V3");
|
|
if (ret == 0) {
|
|
/*
|
|
* Success.
|
|
*/
|
|
return 0;
|
|
}
|
|
if (ret == -1) {
|
|
/*
|
|
* We failed for some reason other than "the
|
|
* kernel doesn't support TPACKET_V3".
|
|
*/
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* This means it returned 1, which means "the kernel
|
|
* doesn't support TPACKET_V3"; try TPACKET_V2.
|
|
*/
|
|
}
|
|
#endif /* HAVE_TPACKET3 */
|
|
|
|
/*
|
|
* Try setting the version to TPACKET_V2.
|
|
*/
|
|
ret = init_tpacket(handle, TPACKET_V2, "TPACKET_V2");
|
|
if (ret == 0) {
|
|
/*
|
|
* Success.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
if (ret == 1) {
|
|
/*
|
|
* OK, the kernel supports memory-mapped capture, but
|
|
* not TPACKET_V2. Set the error message appropriately.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Kernel doesn't support TPACKET_V2; a 2.6.27 or later kernel is required");
|
|
}
|
|
|
|
/*
|
|
* We failed.
|
|
*/
|
|
return -1;
|
|
}
|
|
|
|
#define MAX(a,b) ((a)>(b)?(a):(b))
|
|
|
|
/*
|
|
* Attempt to set up memory-mapped access.
|
|
*
|
|
* On success, returns 1, and sets *status to 0 if there are no warnings
|
|
* or to a PCAP_WARNING_ code if there is a warning.
|
|
*
|
|
* On error, returns -1, and sets *status to the appropriate error code;
|
|
* if that is PCAP_ERROR, sets handle->errbuf to the appropriate message.
|
|
*/
|
|
static int
|
|
create_ring(pcap_t *handle, int *status)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
unsigned i, j, frames_per_block;
|
|
#ifdef HAVE_TPACKET3
|
|
/*
|
|
* For sockets using TPACKET_V2, the extra stuff at the end of a
|
|
* struct tpacket_req3 will be ignored, so this is OK even for
|
|
* those sockets.
|
|
*/
|
|
struct tpacket_req3 req;
|
|
#else
|
|
struct tpacket_req req;
|
|
#endif
|
|
socklen_t len;
|
|
unsigned int sk_type, tp_reserve, maclen, tp_hdrlen, netoff, macoff;
|
|
unsigned int frame_size;
|
|
|
|
/*
|
|
* Start out assuming no warnings or errors.
|
|
*/
|
|
*status = 0;
|
|
|
|
/*
|
|
* Reserve space for VLAN tag reconstruction.
|
|
*/
|
|
tp_reserve = VLAN_TAG_LEN;
|
|
|
|
/*
|
|
* If we're capturing in cooked mode, reserve space for
|
|
* a DLT_LINUX_SLL2 header; we don't know yet whether
|
|
* we'll be using DLT_LINUX_SLL or DLT_LINUX_SLL2, as
|
|
* that can be changed on an open device, so we reserve
|
|
* space for the larger of the two.
|
|
*
|
|
* XXX - we assume that the kernel is still adding
|
|
* 16 bytes of extra space, so we subtract 16 from
|
|
* SLL2_HDR_LEN to get the additional space needed.
|
|
* (Are they doing that for DLT_LINUX_SLL, the link-
|
|
* layer header for which is 16 bytes?)
|
|
*
|
|
* XXX - should we use TPACKET_ALIGN(SLL2_HDR_LEN - 16)?
|
|
*/
|
|
if (handlep->cooked)
|
|
tp_reserve += SLL2_HDR_LEN - 16;
|
|
|
|
/*
|
|
* Try to request that amount of reserve space.
|
|
* This must be done before creating the ring buffer.
|
|
*/
|
|
len = sizeof(tp_reserve);
|
|
if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE,
|
|
&tp_reserve, len) < 0) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"setsockopt (PACKET_RESERVE)");
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
|
|
switch (handlep->tp_version) {
|
|
|
|
case TPACKET_V2:
|
|
/* Note that with large snapshot length (say 256K, which is
|
|
* the default for recent versions of tcpdump, Wireshark,
|
|
* TShark, dumpcap or 64K, the value that "-s 0" has given for
|
|
* a long time with tcpdump), if we use the snapshot
|
|
* length to calculate the frame length, only a few frames
|
|
* will be available in the ring even with pretty
|
|
* large ring size (and a lot of memory will be unused).
|
|
*
|
|
* Ideally, we should choose a frame length based on the
|
|
* minimum of the specified snapshot length and the maximum
|
|
* packet size. That's not as easy as it sounds; consider,
|
|
* for example, an 802.11 interface in monitor mode, where
|
|
* the frame would include a radiotap header, where the
|
|
* maximum radiotap header length is device-dependent.
|
|
*
|
|
* So, for now, we just do this for Ethernet devices, where
|
|
* there's no metadata header, and the link-layer header is
|
|
* fixed length. We can get the maximum packet size by
|
|
* adding 18, the Ethernet header length plus the CRC length
|
|
* (just in case we happen to get the CRC in the packet), to
|
|
* the MTU of the interface; we fetch the MTU in the hopes
|
|
* that it reflects support for jumbo frames. (Even if the
|
|
* interface is just being used for passive snooping, the
|
|
* driver might set the size of buffers in the receive ring
|
|
* based on the MTU, so that the MTU limits the maximum size
|
|
* of packets that we can receive.)
|
|
*
|
|
* If segmentation/fragmentation or receive offload are
|
|
* enabled, we can get reassembled/aggregated packets larger
|
|
* than MTU, but bounded to 65535 plus the Ethernet overhead,
|
|
* due to kernel and protocol constraints */
|
|
frame_size = handle->snapshot;
|
|
if (handle->linktype == DLT_EN10MB) {
|
|
unsigned int max_frame_len;
|
|
int mtu;
|
|
int offload;
|
|
|
|
mtu = iface_get_mtu(handle->fd, handle->opt.device,
|
|
handle->errbuf);
|
|
if (mtu == -1) {
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
offload = iface_get_offload(handle);
|
|
if (offload == -1) {
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
if (offload)
|
|
max_frame_len = MAX(mtu, 65535);
|
|
else
|
|
max_frame_len = mtu;
|
|
max_frame_len += 18;
|
|
|
|
if (frame_size > max_frame_len)
|
|
frame_size = max_frame_len;
|
|
}
|
|
|
|
/* NOTE: calculus matching those in tpacket_rcv()
|
|
* in linux-2.6/net/packet/af_packet.c
|
|
*/
|
|
len = sizeof(sk_type);
|
|
if (getsockopt(handle->fd, SOL_SOCKET, SO_TYPE, &sk_type,
|
|
&len) < 0) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno, "getsockopt (SO_TYPE)");
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
maclen = (sk_type == SOCK_DGRAM) ? 0 : MAX_LINKHEADER_SIZE;
|
|
/* XXX: in the kernel maclen is calculated from
|
|
* LL_ALLOCATED_SPACE(dev) and vnet_hdr.hdr_len
|
|
* in: packet_snd() in linux-2.6/net/packet/af_packet.c
|
|
* then packet_alloc_skb() in linux-2.6/net/packet/af_packet.c
|
|
* then sock_alloc_send_pskb() in linux-2.6/net/core/sock.c
|
|
* but I see no way to get those sizes in userspace,
|
|
* like for instance with an ifreq ioctl();
|
|
* the best thing I've found so far is MAX_HEADER in
|
|
* the kernel part of linux-2.6/include/linux/netdevice.h
|
|
* which goes up to 128+48=176; since pcap-linux.c
|
|
* defines a MAX_LINKHEADER_SIZE of 256 which is
|
|
* greater than that, let's use it.. maybe is it even
|
|
* large enough to directly replace macoff..
|
|
*/
|
|
tp_hdrlen = TPACKET_ALIGN(handlep->tp_hdrlen) + sizeof(struct sockaddr_ll) ;
|
|
netoff = TPACKET_ALIGN(tp_hdrlen + (maclen < 16 ? 16 : maclen)) + tp_reserve;
|
|
/* NOTE: AFAICS tp_reserve may break the TPACKET_ALIGN
|
|
* of netoff, which contradicts
|
|
* linux-2.6/Documentation/networking/packet_mmap.txt
|
|
* documenting that:
|
|
* "- Gap, chosen so that packet data (Start+tp_net)
|
|
* aligns to TPACKET_ALIGNMENT=16"
|
|
*/
|
|
/* NOTE: in linux-2.6/include/linux/skbuff.h:
|
|
* "CPUs often take a performance hit
|
|
* when accessing unaligned memory locations"
|
|
*/
|
|
macoff = netoff - maclen;
|
|
req.tp_frame_size = TPACKET_ALIGN(macoff + frame_size);
|
|
/*
|
|
* Round the buffer size up to a multiple of the
|
|
* frame size (rather than rounding down, which
|
|
* would give a buffer smaller than our caller asked
|
|
* for, and possibly give zero frames if the requested
|
|
* buffer size is too small for one frame).
|
|
*/
|
|
req.tp_frame_nr = (handle->opt.buffer_size + req.tp_frame_size - 1)/req.tp_frame_size;
|
|
break;
|
|
|
|
#ifdef HAVE_TPACKET3
|
|
case TPACKET_V3:
|
|
/* The "frames" for this are actually buffers that
|
|
* contain multiple variable-sized frames.
|
|
*
|
|
* We pick a "frame" size of MAXIMUM_SNAPLEN to leave
|
|
* enough room for at least one reasonably-sized packet
|
|
* in the "frame". */
|
|
req.tp_frame_size = MAXIMUM_SNAPLEN;
|
|
/*
|
|
* Round the buffer size up to a multiple of the
|
|
* "frame" size (rather than rounding down, which
|
|
* would give a buffer smaller than our caller asked
|
|
* for, and possibly give zero "frames" if the requested
|
|
* buffer size is too small for one "frame").
|
|
*/
|
|
req.tp_frame_nr = (handle->opt.buffer_size + req.tp_frame_size - 1)/req.tp_frame_size;
|
|
break;
|
|
#endif
|
|
default:
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Internal error: unknown TPACKET_ value %u",
|
|
handlep->tp_version);
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
|
|
/* compute the minimum block size that will handle this frame.
|
|
* The block has to be page size aligned.
|
|
* The max block size allowed by the kernel is arch-dependent and
|
|
* it's not explicitly checked here. */
|
|
req.tp_block_size = getpagesize();
|
|
while (req.tp_block_size < req.tp_frame_size)
|
|
req.tp_block_size <<= 1;
|
|
|
|
frames_per_block = req.tp_block_size/req.tp_frame_size;
|
|
|
|
/*
|
|
* PACKET_TIMESTAMP was added after linux/net_tstamp.h was,
|
|
* so we check for PACKET_TIMESTAMP. We check for
|
|
* linux/net_tstamp.h just in case a system somehow has
|
|
* PACKET_TIMESTAMP but not linux/net_tstamp.h; that might
|
|
* be unnecessary.
|
|
*
|
|
* SIOCSHWTSTAMP was introduced in the patch that introduced
|
|
* linux/net_tstamp.h, so we don't bother checking whether
|
|
* SIOCSHWTSTAMP is defined (if your Linux system has
|
|
* linux/net_tstamp.h but doesn't define SIOCSHWTSTAMP, your
|
|
* Linux system is badly broken).
|
|
*/
|
|
#if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
|
|
/*
|
|
* If we were told to do so, ask the kernel and the driver
|
|
* to use hardware timestamps.
|
|
*
|
|
* Hardware timestamps are only supported with mmapped
|
|
* captures.
|
|
*/
|
|
if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER ||
|
|
handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER_UNSYNCED) {
|
|
struct hwtstamp_config hwconfig;
|
|
struct ifreq ifr;
|
|
int timesource;
|
|
|
|
/*
|
|
* Ask for hardware time stamps on all packets,
|
|
* including transmitted packets.
|
|
*/
|
|
memset(&hwconfig, 0, sizeof(hwconfig));
|
|
hwconfig.tx_type = HWTSTAMP_TX_ON;
|
|
hwconfig.rx_filter = HWTSTAMP_FILTER_ALL;
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, handle->opt.device, sizeof(ifr.ifr_name));
|
|
ifr.ifr_data = (void *)&hwconfig;
|
|
|
|
/*
|
|
* This may require CAP_NET_ADMIN.
|
|
*/
|
|
if (ioctl(handle->fd, SIOCSHWTSTAMP, &ifr) < 0) {
|
|
switch (errno) {
|
|
|
|
case EPERM:
|
|
/*
|
|
* Treat this as an error, as the
|
|
* user should try to run this
|
|
* with the appropriate privileges -
|
|
* and, if they can't, shouldn't
|
|
* try requesting hardware time stamps.
|
|
*/
|
|
*status = PCAP_ERROR_PERM_DENIED;
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Attempt to set hardware timestamp failed - CAP_NET_ADMIN may be required");
|
|
return -1;
|
|
|
|
case EOPNOTSUPP:
|
|
case ERANGE:
|
|
/*
|
|
* Treat this as a warning, as the
|
|
* only way to fix the warning is to
|
|
* get an adapter that supports hardware
|
|
* time stamps for *all* packets.
|
|
* (ERANGE means "we support hardware
|
|
* time stamps, but for packets matching
|
|
* that particular filter", so it means
|
|
* "we don't support hardware time stamps
|
|
* for all incoming packets" here.)
|
|
*
|
|
* We'll just fall back on the standard
|
|
* host time stamps.
|
|
*/
|
|
*status = PCAP_WARNING_TSTAMP_TYPE_NOTSUP;
|
|
break;
|
|
|
|
default:
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"SIOCSHWTSTAMP failed");
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
} else {
|
|
/*
|
|
* Well, that worked. Now specify the type of
|
|
* hardware time stamp we want for this
|
|
* socket.
|
|
*/
|
|
if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER) {
|
|
/*
|
|
* Hardware timestamp, synchronized
|
|
* with the system clock.
|
|
*/
|
|
timesource = SOF_TIMESTAMPING_SYS_HARDWARE;
|
|
} else {
|
|
/*
|
|
* PCAP_TSTAMP_ADAPTER_UNSYNCED - hardware
|
|
* timestamp, not synchronized with the
|
|
* system clock.
|
|
*/
|
|
timesource = SOF_TIMESTAMPING_RAW_HARDWARE;
|
|
}
|
|
if (setsockopt(handle->fd, SOL_PACKET, PACKET_TIMESTAMP,
|
|
(void *)×ource, sizeof(timesource))) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"can't set PACKET_TIMESTAMP");
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
}
|
|
}
|
|
#endif /* HAVE_LINUX_NET_TSTAMP_H && PACKET_TIMESTAMP */
|
|
|
|
/* ask the kernel to create the ring */
|
|
retry:
|
|
req.tp_block_nr = req.tp_frame_nr / frames_per_block;
|
|
|
|
/* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */
|
|
req.tp_frame_nr = req.tp_block_nr * frames_per_block;
|
|
|
|
#ifdef HAVE_TPACKET3
|
|
/* timeout value to retire block - use the configured buffering timeout, or default if <0. */
|
|
if (handlep->timeout > 0) {
|
|
/* Use the user specified timeout as the block timeout */
|
|
req.tp_retire_blk_tov = handlep->timeout;
|
|
} else if (handlep->timeout == 0) {
|
|
/*
|
|
* In pcap, this means "infinite timeout"; TPACKET_V3
|
|
* doesn't support that, so just set it to UINT_MAX
|
|
* milliseconds. In the TPACKET_V3 loop, if the
|
|
* timeout is 0, and we haven't yet seen any packets,
|
|
* and we block and still don't have any packets, we
|
|
* keep blocking until we do.
|
|
*/
|
|
req.tp_retire_blk_tov = UINT_MAX;
|
|
} else {
|
|
/*
|
|
* XXX - this is not valid; use 0, meaning "have the
|
|
* kernel pick a default", for now.
|
|
*/
|
|
req.tp_retire_blk_tov = 0;
|
|
}
|
|
/* private data not used */
|
|
req.tp_sizeof_priv = 0;
|
|
/* Rx ring - feature request bits - none (rxhash will not be filled) */
|
|
req.tp_feature_req_word = 0;
|
|
#endif
|
|
|
|
if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
|
|
(void *) &req, sizeof(req))) {
|
|
if ((errno == ENOMEM) && (req.tp_block_nr > 1)) {
|
|
/*
|
|
* Memory failure; try to reduce the requested ring
|
|
* size.
|
|
*
|
|
* We used to reduce this by half -- do 5% instead.
|
|
* That may result in more iterations and a longer
|
|
* startup, but the user will be much happier with
|
|
* the resulting buffer size.
|
|
*/
|
|
if (req.tp_frame_nr < 20)
|
|
req.tp_frame_nr -= 1;
|
|
else
|
|
req.tp_frame_nr -= req.tp_frame_nr/20;
|
|
goto retry;
|
|
}
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "can't create rx ring on packet socket");
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
|
|
/* memory map the rx ring */
|
|
handlep->mmapbuflen = req.tp_block_nr * req.tp_block_size;
|
|
handlep->mmapbuf = mmap(0, handlep->mmapbuflen,
|
|
PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0);
|
|
if (handlep->mmapbuf == MAP_FAILED) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "can't mmap rx ring");
|
|
|
|
/* clear the allocated ring on error*/
|
|
destroy_ring(handle);
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
|
|
/* allocate a ring for each frame header pointer*/
|
|
handle->cc = req.tp_frame_nr;
|
|
handle->buffer = malloc(handle->cc * sizeof(union thdr *));
|
|
if (!handle->buffer) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "can't allocate ring of frame headers");
|
|
|
|
destroy_ring(handle);
|
|
*status = PCAP_ERROR;
|
|
return -1;
|
|
}
|
|
|
|
/* fill the header ring with proper frame ptr*/
|
|
handle->offset = 0;
|
|
for (i=0; i<req.tp_block_nr; ++i) {
|
|
u_char *base = &handlep->mmapbuf[i*req.tp_block_size];
|
|
for (j=0; j<frames_per_block; ++j, ++handle->offset) {
|
|
RING_GET_CURRENT_FRAME(handle) = base;
|
|
base += req.tp_frame_size;
|
|
}
|
|
}
|
|
|
|
handle->bufsize = req.tp_frame_size;
|
|
handle->offset = 0;
|
|
return 1;
|
|
}
|
|
|
|
/* free all ring related resources*/
|
|
static void
|
|
destroy_ring(pcap_t *handle)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
|
|
/*
|
|
* Tell the kernel to destroy the ring.
|
|
* We don't check for setsockopt failure, as 1) we can't recover
|
|
* from an error and 2) we might not yet have set it up in the
|
|
* first place.
|
|
*/
|
|
struct tpacket_req req;
|
|
memset(&req, 0, sizeof(req));
|
|
(void)setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
|
|
(void *) &req, sizeof(req));
|
|
|
|
/* if ring is mapped, unmap it*/
|
|
if (handlep->mmapbuf) {
|
|
/* do not test for mmap failure, as we can't recover from any error */
|
|
(void)munmap(handlep->mmapbuf, handlep->mmapbuflen);
|
|
handlep->mmapbuf = NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Special one-shot callback, used for pcap_next() and pcap_next_ex(),
|
|
* for Linux mmapped capture.
|
|
*
|
|
* The problem is that pcap_next() and pcap_next_ex() expect the packet
|
|
* data handed to the callback to be valid after the callback returns,
|
|
* but pcap_read_linux_mmap() has to release that packet as soon as
|
|
* the callback returns (otherwise, the kernel thinks there's still
|
|
* at least one unprocessed packet available in the ring, so a select()
|
|
* will immediately return indicating that there's data to process), so,
|
|
* in the callback, we have to make a copy of the packet.
|
|
*
|
|
* Yes, this means that, if the capture is using the ring buffer, using
|
|
* pcap_next() or pcap_next_ex() requires more copies than using
|
|
* pcap_loop() or pcap_dispatch(). If that bothers you, don't use
|
|
* pcap_next() or pcap_next_ex().
|
|
*/
|
|
static void
|
|
pcap_oneshot_linux(u_char *user, const struct pcap_pkthdr *h,
|
|
const u_char *bytes)
|
|
{
|
|
struct oneshot_userdata *sp = (struct oneshot_userdata *)user;
|
|
pcap_t *handle = sp->pd;
|
|
struct pcap_linux *handlep = handle->priv;
|
|
|
|
*sp->hdr = *h;
|
|
memcpy(handlep->oneshot_buffer, bytes, h->caplen);
|
|
*sp->pkt = handlep->oneshot_buffer;
|
|
}
|
|
|
|
static int
|
|
pcap_getnonblock_linux(pcap_t *handle)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
|
|
/* use negative value of timeout to indicate non blocking ops */
|
|
return (handlep->timeout<0);
|
|
}
|
|
|
|
static int
|
|
pcap_setnonblock_linux(pcap_t *handle, int nonblock)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
|
|
/*
|
|
* Set the file descriptor to non-blocking mode, as we use
|
|
* it for sending packets.
|
|
*/
|
|
if (pcap_setnonblock_fd(handle, nonblock) == -1)
|
|
return -1;
|
|
|
|
/*
|
|
* Map each value to their corresponding negation to
|
|
* preserve the timeout value provided with pcap_set_timeout.
|
|
*/
|
|
if (nonblock) {
|
|
if (handlep->timeout >= 0) {
|
|
/*
|
|
* Indicate that we're switching to
|
|
* non-blocking mode.
|
|
*/
|
|
handlep->timeout = ~handlep->timeout;
|
|
}
|
|
if (handlep->poll_breakloop_fd != -1) {
|
|
/* Close the eventfd; we do not need it in nonblock mode. */
|
|
close(handlep->poll_breakloop_fd);
|
|
handlep->poll_breakloop_fd = -1;
|
|
}
|
|
} else {
|
|
if (handlep->poll_breakloop_fd == -1) {
|
|
/* If we did not have an eventfd, open one now that we are blocking. */
|
|
if ( ( handlep->poll_breakloop_fd = eventfd(0, EFD_NONBLOCK) ) == -1 ) {
|
|
int save_errno = errno;
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Could not open eventfd: %s",
|
|
strerror(errno));
|
|
errno = save_errno;
|
|
return -1;
|
|
}
|
|
}
|
|
if (handlep->timeout < 0) {
|
|
handlep->timeout = ~handlep->timeout;
|
|
}
|
|
}
|
|
/* Update the timeout to use in poll(). */
|
|
set_poll_timeout(handlep);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Get the status field of the ring buffer frame at a specified offset.
|
|
*/
|
|
static inline u_int
|
|
pcap_get_ring_frame_status(pcap_t *handle, int offset)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
union thdr h;
|
|
|
|
h.raw = RING_GET_FRAME_AT(handle, offset);
|
|
switch (handlep->tp_version) {
|
|
case TPACKET_V2:
|
|
return __atomic_load_n(&h.h2->tp_status, __ATOMIC_ACQUIRE);
|
|
break;
|
|
#ifdef HAVE_TPACKET3
|
|
case TPACKET_V3:
|
|
return __atomic_load_n(&h.h3->hdr.bh1.block_status, __ATOMIC_ACQUIRE);
|
|
break;
|
|
#endif
|
|
}
|
|
/* This should not happen. */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Block waiting for frames to be available.
|
|
*/
|
|
static int pcap_wait_for_frames_mmap(pcap_t *handle)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
int timeout;
|
|
struct ifreq ifr;
|
|
int ret;
|
|
struct pollfd pollinfo[2];
|
|
int numpollinfo;
|
|
pollinfo[0].fd = handle->fd;
|
|
pollinfo[0].events = POLLIN;
|
|
if ( handlep->poll_breakloop_fd == -1 ) {
|
|
numpollinfo = 1;
|
|
pollinfo[1].revents = 0;
|
|
/*
|
|
* We set pollinfo[1].revents to zero, even though
|
|
* numpollinfo = 1 meaning that poll() doesn't see
|
|
* pollinfo[1], so that we do not have to add a
|
|
* conditional of numpollinfo > 1 below when we
|
|
* test pollinfo[1].revents.
|
|
*/
|
|
} else {
|
|
pollinfo[1].fd = handlep->poll_breakloop_fd;
|
|
pollinfo[1].events = POLLIN;
|
|
numpollinfo = 2;
|
|
}
|
|
|
|
/*
|
|
* Keep polling until we either get some packets to read, see
|
|
* that we got told to break out of the loop, get a fatal error,
|
|
* or discover that the device went away.
|
|
*
|
|
* In non-blocking mode, we must still do one poll() to catch
|
|
* any pending error indications, but the poll() has a timeout
|
|
* of 0, so that it doesn't block, and we quit after that one
|
|
* poll().
|
|
*
|
|
* If we've seen an ENETDOWN, it might be the first indication
|
|
* that the device went away, or it might just be that it was
|
|
* configured down. Unfortunately, there's no guarantee that
|
|
* the device has actually been removed as an interface, because:
|
|
*
|
|
* 1) if, as appears to be the case at least some of the time,
|
|
* the PF_PACKET socket code first gets a NETDEV_DOWN indication
|
|
* for the device and then gets a NETDEV_UNREGISTER indication
|
|
* for it, the first indication will cause a wakeup with ENETDOWN
|
|
* but won't set the packet socket's field for the interface index
|
|
* to -1, and the second indication won't cause a wakeup (because
|
|
* the first indication also caused the protocol hook to be
|
|
* unregistered) but will set the packet socket's field for the
|
|
* interface index to -1;
|
|
*
|
|
* 2) even if just a NETDEV_UNREGISTER indication is registered,
|
|
* the packet socket's field for the interface index only gets
|
|
* set to -1 after the wakeup, so there's a small but non-zero
|
|
* risk that a thread blocked waiting for the wakeup will get
|
|
* to the "fetch the socket name" code before the interface index
|
|
* gets set to -1, so it'll get the old interface index.
|
|
*
|
|
* Therefore, if we got an ENETDOWN and haven't seen a packet
|
|
* since then, we assume that we might be waiting for the interface
|
|
* to disappear, and poll with a timeout to try again in a short
|
|
* period of time. If we *do* see a packet, the interface has
|
|
* come back up again, and is *definitely* still there, so we
|
|
* don't need to poll.
|
|
*/
|
|
for (;;) {
|
|
/*
|
|
* Yes, we do this even in non-blocking mode, as it's
|
|
* the only way to get error indications from a
|
|
* tpacket socket.
|
|
*
|
|
* The timeout is 0 in non-blocking mode, so poll()
|
|
* returns immediately.
|
|
*/
|
|
timeout = handlep->poll_timeout;
|
|
|
|
/*
|
|
* If we got an ENETDOWN and haven't gotten an indication
|
|
* that the device has gone away or that the device is up,
|
|
* we don't yet know for certain whether the device has
|
|
* gone away or not, do a poll() with a 1-millisecond timeout,
|
|
* as we have to poll indefinitely for "device went away"
|
|
* indications until we either get one or see that the
|
|
* device is up.
|
|
*/
|
|
if (handlep->netdown) {
|
|
if (timeout != 0)
|
|
timeout = 1;
|
|
}
|
|
ret = poll(pollinfo, numpollinfo, timeout);
|
|
if (ret < 0) {
|
|
/*
|
|
* Error. If it's not EINTR, report it.
|
|
*/
|
|
if (errno != EINTR) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"can't poll on packet socket");
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* It's EINTR; if we were told to break out of
|
|
* the loop, do so.
|
|
*/
|
|
if (handle->break_loop) {
|
|
handle->break_loop = 0;
|
|
return PCAP_ERROR_BREAK;
|
|
}
|
|
} else if (ret > 0) {
|
|
/*
|
|
* OK, some descriptor is ready.
|
|
* Check the socket descriptor first.
|
|
*
|
|
* As I read the Linux man page, pollinfo[0].revents
|
|
* will either be POLLIN, POLLERR, POLLHUP, or POLLNVAL.
|
|
*/
|
|
if (pollinfo[0].revents == POLLIN) {
|
|
/*
|
|
* OK, we may have packets to
|
|
* read.
|
|
*/
|
|
break;
|
|
}
|
|
if (pollinfo[0].revents != 0) {
|
|
/*
|
|
* There's some indication other than
|
|
* "you can read on this descriptor" on
|
|
* the descriptor.
|
|
*/
|
|
if (pollinfo[0].revents & POLLNVAL) {
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"Invalid polling request on packet socket");
|
|
return PCAP_ERROR;
|
|
}
|
|
if (pollinfo[0].revents & (POLLHUP | POLLRDHUP)) {
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"Hangup on packet socket");
|
|
return PCAP_ERROR;
|
|
}
|
|
if (pollinfo[0].revents & POLLERR) {
|
|
/*
|
|
* Get the error.
|
|
*/
|
|
int err;
|
|
socklen_t errlen;
|
|
|
|
errlen = sizeof(err);
|
|
if (getsockopt(handle->fd, SOL_SOCKET,
|
|
SO_ERROR, &err, &errlen) == -1) {
|
|
/*
|
|
* The call *itself* returned
|
|
* an error; make *that*
|
|
* the error.
|
|
*/
|
|
err = errno;
|
|
}
|
|
|
|
/*
|
|
* OK, we have the error.
|
|
*/
|
|
if (err == ENETDOWN) {
|
|
/*
|
|
* The device on which we're
|
|
* capturing went away or the
|
|
* interface was taken down.
|
|
*
|
|
* We don't know for certain
|
|
* which happened, and the
|
|
* next poll() may indicate
|
|
* that there are packets
|
|
* to be read, so just set
|
|
* a flag to get us to do
|
|
* checks later, and set
|
|
* the required select
|
|
* timeout to 1 millisecond
|
|
* so that event loops that
|
|
* check our socket descriptor
|
|
* also time out so that
|
|
* they can call us and we
|
|
* can do the checks.
|
|
*/
|
|
handlep->netdown = 1;
|
|
handle->required_select_timeout = &netdown_timeout;
|
|
} else if (err == 0) {
|
|
/*
|
|
* This shouldn't happen, so
|
|
* report a special indication
|
|
* that it did.
|
|
*/
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"Error condition on packet socket: Reported error was 0");
|
|
return PCAP_ERROR;
|
|
} else {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
err,
|
|
"Error condition on packet socket");
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* Now check the event device.
|
|
*/
|
|
if (pollinfo[1].revents & POLLIN) {
|
|
ssize_t nread;
|
|
uint64_t value;
|
|
|
|
/*
|
|
* This should never fail, but, just
|
|
* in case....
|
|
*/
|
|
nread = read(handlep->poll_breakloop_fd, &value,
|
|
sizeof(value));
|
|
if (nread == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
errno,
|
|
"Error reading from event FD");
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* According to the Linux read(2) man
|
|
* page, read() will transfer at most
|
|
* 2^31-1 bytes, so the return value is
|
|
* either -1 or a value between 0
|
|
* and 2^31-1, so it's non-negative.
|
|
*
|
|
* Cast it to size_t to squelch
|
|
* warnings from the compiler; add this
|
|
* comment to squelch warnings from
|
|
* humans reading the code. :-)
|
|
*
|
|
* Don't treat an EOF as an error, but
|
|
* *do* treat a short read as an error;
|
|
* that "shouldn't happen", but....
|
|
*/
|
|
if (nread != 0 &&
|
|
(size_t)nread < sizeof(value)) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Short read from event FD: expected %zu, got %zd",
|
|
sizeof(value), nread);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* This event gets signaled by a
|
|
* pcap_breakloop() call; if we were told
|
|
* to break out of the loop, do so.
|
|
*/
|
|
if (handle->break_loop) {
|
|
handle->break_loop = 0;
|
|
return PCAP_ERROR_BREAK;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Either:
|
|
*
|
|
* 1) we got neither an error from poll() nor any
|
|
* readable descriptors, in which case there
|
|
* are no packets waiting to read
|
|
*
|
|
* or
|
|
*
|
|
* 2) We got readable descriptors but the PF_PACKET
|
|
* socket wasn't one of them, in which case there
|
|
* are no packets waiting to read
|
|
*
|
|
* so, if we got an ENETDOWN, we've drained whatever
|
|
* packets were available to read at the point of the
|
|
* ENETDOWN.
|
|
*
|
|
* So, if we got an ENETDOWN and haven't gotten an indication
|
|
* that the device has gone away or that the device is up,
|
|
* we don't yet know for certain whether the device has
|
|
* gone away or not, check whether the device exists and is
|
|
* up.
|
|
*/
|
|
if (handlep->netdown) {
|
|
if (!device_still_exists(handle)) {
|
|
/*
|
|
* The device doesn't exist any more;
|
|
* report that.
|
|
*
|
|
* XXX - we should really return an
|
|
* appropriate error for that, but
|
|
* pcap_dispatch() etc. aren't documented
|
|
* as having error returns other than
|
|
* PCAP_ERROR or PCAP_ERROR_BREAK.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"The interface disappeared");
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* The device still exists; try to see if it's up.
|
|
*/
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, handlep->device,
|
|
sizeof(ifr.ifr_name));
|
|
if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
|
|
if (errno == ENXIO || errno == ENODEV) {
|
|
/*
|
|
* OK, *now* it's gone.
|
|
*
|
|
* XXX - see above comment.
|
|
*/
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"The interface disappeared");
|
|
return PCAP_ERROR;
|
|
} else {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"%s: Can't get flags",
|
|
handlep->device);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
if (ifr.ifr_flags & IFF_UP) {
|
|
/*
|
|
* It's up, so it definitely still exists.
|
|
* Cancel the ENETDOWN indication - we
|
|
* presumably got it due to the interface
|
|
* going down rather than the device going
|
|
* away - and revert to "no required select
|
|
* timeout.
|
|
*/
|
|
handlep->netdown = 0;
|
|
handle->required_select_timeout = NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we're in non-blocking mode, just quit now, rather
|
|
* than spinning in a loop doing poll()s that immediately
|
|
* time out if there's no indication on any descriptor.
|
|
*/
|
|
if (handlep->poll_timeout == 0)
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* handle a single memory mapped packet */
|
|
static int pcap_handle_packet_mmap(
|
|
pcap_t *handle,
|
|
pcap_handler callback,
|
|
u_char *user,
|
|
unsigned char *frame,
|
|
unsigned int tp_len,
|
|
unsigned int tp_mac,
|
|
unsigned int tp_snaplen,
|
|
unsigned int tp_sec,
|
|
unsigned int tp_usec,
|
|
int tp_vlan_tci_valid,
|
|
__u16 tp_vlan_tci,
|
|
__u16 tp_vlan_tpid)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
unsigned char *bp;
|
|
struct sockaddr_ll *sll;
|
|
struct pcap_pkthdr pcaphdr;
|
|
pcap_can_socketcan_hdr *canhdr;
|
|
unsigned int snaplen = tp_snaplen;
|
|
struct utsname utsname;
|
|
|
|
/* perform sanity check on internal offset. */
|
|
if (tp_mac + tp_snaplen > handle->bufsize) {
|
|
/*
|
|
* Report some system information as a debugging aid.
|
|
*/
|
|
if (uname(&utsname) != -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"corrupted frame on kernel ring mac "
|
|
"offset %u + caplen %u > frame len %d "
|
|
"(kernel %.32s version %s, machine %.16s)",
|
|
tp_mac, tp_snaplen, handle->bufsize,
|
|
utsname.release, utsname.version,
|
|
utsname.machine);
|
|
} else {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"corrupted frame on kernel ring mac "
|
|
"offset %u + caplen %u > frame len %d",
|
|
tp_mac, tp_snaplen, handle->bufsize);
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/* run filter on received packet
|
|
* If the kernel filtering is enabled we need to run the
|
|
* filter until all the frames present into the ring
|
|
* at filter creation time are processed.
|
|
* In this case, blocks_to_filter_in_userland is used
|
|
* as a counter for the packet we need to filter.
|
|
* Note: alternatively it could be possible to stop applying
|
|
* the filter when the ring became empty, but it can possibly
|
|
* happen a lot later... */
|
|
bp = frame + tp_mac;
|
|
|
|
/* if required build in place the sll header*/
|
|
sll = (void *)(frame + TPACKET_ALIGN(handlep->tp_hdrlen));
|
|
if (handlep->cooked) {
|
|
if (handle->linktype == DLT_LINUX_SLL2) {
|
|
struct sll2_header *hdrp;
|
|
|
|
/*
|
|
* The kernel should have left us with enough
|
|
* space for an sll header; back up the packet
|
|
* data pointer into that space, as that'll be
|
|
* the beginning of the packet we pass to the
|
|
* callback.
|
|
*/
|
|
bp -= SLL2_HDR_LEN;
|
|
|
|
/*
|
|
* Let's make sure that's past the end of
|
|
* the tpacket header, i.e. >=
|
|
* ((u_char *)thdr + TPACKET_HDRLEN), so we
|
|
* don't step on the header when we construct
|
|
* the sll header.
|
|
*/
|
|
if (bp < (u_char *)frame +
|
|
TPACKET_ALIGN(handlep->tp_hdrlen) +
|
|
sizeof(struct sockaddr_ll)) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"cooked-mode frame doesn't have room for sll header");
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* OK, that worked; construct the sll header.
|
|
*/
|
|
hdrp = (struct sll2_header *)bp;
|
|
hdrp->sll2_protocol = sll->sll_protocol;
|
|
hdrp->sll2_reserved_mbz = 0;
|
|
hdrp->sll2_if_index = htonl(sll->sll_ifindex);
|
|
hdrp->sll2_hatype = htons(sll->sll_hatype);
|
|
hdrp->sll2_pkttype = sll->sll_pkttype;
|
|
hdrp->sll2_halen = sll->sll_halen;
|
|
memcpy(hdrp->sll2_addr, sll->sll_addr, SLL_ADDRLEN);
|
|
|
|
snaplen += sizeof(struct sll2_header);
|
|
} else {
|
|
struct sll_header *hdrp;
|
|
|
|
/*
|
|
* The kernel should have left us with enough
|
|
* space for an sll header; back up the packet
|
|
* data pointer into that space, as that'll be
|
|
* the beginning of the packet we pass to the
|
|
* callback.
|
|
*/
|
|
bp -= SLL_HDR_LEN;
|
|
|
|
/*
|
|
* Let's make sure that's past the end of
|
|
* the tpacket header, i.e. >=
|
|
* ((u_char *)thdr + TPACKET_HDRLEN), so we
|
|
* don't step on the header when we construct
|
|
* the sll header.
|
|
*/
|
|
if (bp < (u_char *)frame +
|
|
TPACKET_ALIGN(handlep->tp_hdrlen) +
|
|
sizeof(struct sockaddr_ll)) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"cooked-mode frame doesn't have room for sll header");
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* OK, that worked; construct the sll header.
|
|
*/
|
|
hdrp = (struct sll_header *)bp;
|
|
hdrp->sll_pkttype = htons(sll->sll_pkttype);
|
|
hdrp->sll_hatype = htons(sll->sll_hatype);
|
|
hdrp->sll_halen = htons(sll->sll_halen);
|
|
memcpy(hdrp->sll_addr, sll->sll_addr, SLL_ADDRLEN);
|
|
hdrp->sll_protocol = sll->sll_protocol;
|
|
|
|
snaplen += sizeof(struct sll_header);
|
|
}
|
|
} else {
|
|
/*
|
|
* If this is a packet from a CAN device, so that
|
|
* sll->sll_hatype is ARPHRD_CAN, then, as we're
|
|
* not capturing in cooked mode, its link-layer
|
|
* type is DLT_CAN_SOCKETCAN. Fix up the header
|
|
* provided by the code below us to match what
|
|
* DLT_CAN_SOCKETCAN is expected to provide.
|
|
*/
|
|
if (sll->sll_hatype == ARPHRD_CAN) {
|
|
/*
|
|
* DLT_CAN_SOCKETCAN is specified as having the
|
|
* CAN ID and flags in network byte order, but
|
|
* capturing on a CAN device provides it in host
|
|
* byte order. Convert it to network byte order.
|
|
*/
|
|
canhdr = (pcap_can_socketcan_hdr *)bp;
|
|
canhdr->can_id = htonl(canhdr->can_id);
|
|
|
|
/*
|
|
* In addition, set the CANFD_FDF flag if
|
|
* the protocol is LINUX_SLL_P_CANFD, as
|
|
* the protocol field itself isn't in
|
|
* the packet to indicate that it's a
|
|
* CAN FD packet.
|
|
*/
|
|
uint16_t protocol = ntohs(sll->sll_protocol);
|
|
if (protocol == LINUX_SLL_P_CANFD) {
|
|
canhdr->fd_flags |= CANFD_FDF;
|
|
|
|
/*
|
|
* Zero out all the unknown bits in
|
|
* fd_flags and clear the reserved
|
|
* fields, so that a program reading
|
|
* this can assume that CANFD_FDF
|
|
* is set because we set it, not
|
|
* because some uninitialized crap
|
|
* was provided in the fd_flags
|
|
* field.
|
|
*
|
|
* (At least some LINKTYPE_CAN_SOCKETCAN
|
|
* files attached to Wireshark bugs
|
|
* had uninitialized junk there, so it
|
|
* does happen.)
|
|
*
|
|
* Update this if Linux adds more flag
|
|
* bits to the fd_flags field or uses
|
|
* either of the reserved fields for
|
|
* FD frames.
|
|
*/
|
|
canhdr->fd_flags &= ~(CANFD_FDF|CANFD_ESI|CANFD_BRS);
|
|
canhdr->reserved1 = 0;
|
|
canhdr->reserved2 = 0;
|
|
} else {
|
|
/*
|
|
* Clear CANFD_FDF if it's set (probably
|
|
* again meaning that this field is
|
|
* uninitialized junk).
|
|
*/
|
|
canhdr->fd_flags &= ~CANFD_FDF;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (handlep->filter_in_userland && handle->fcode.bf_insns) {
|
|
struct pcap_bpf_aux_data aux_data;
|
|
|
|
aux_data.vlan_tag_present = tp_vlan_tci_valid;
|
|
aux_data.vlan_tag = tp_vlan_tci & 0x0fff;
|
|
|
|
if (pcap_filter_with_aux_data(handle->fcode.bf_insns,
|
|
bp,
|
|
tp_len,
|
|
snaplen,
|
|
&aux_data) == 0)
|
|
return 0;
|
|
}
|
|
|
|
if (!linux_check_direction(handle, sll))
|
|
return 0;
|
|
|
|
/* get required packet info from ring header */
|
|
pcaphdr.ts.tv_sec = tp_sec;
|
|
pcaphdr.ts.tv_usec = tp_usec;
|
|
pcaphdr.caplen = tp_snaplen;
|
|
pcaphdr.len = tp_len;
|
|
|
|
/* if required build in place the sll header*/
|
|
if (handlep->cooked) {
|
|
/* update packet len */
|
|
if (handle->linktype == DLT_LINUX_SLL2) {
|
|
pcaphdr.caplen += SLL2_HDR_LEN;
|
|
pcaphdr.len += SLL2_HDR_LEN;
|
|
} else {
|
|
pcaphdr.caplen += SLL_HDR_LEN;
|
|
pcaphdr.len += SLL_HDR_LEN;
|
|
}
|
|
}
|
|
|
|
if (tp_vlan_tci_valid &&
|
|
handlep->vlan_offset != -1 &&
|
|
tp_snaplen >= (unsigned int) handlep->vlan_offset)
|
|
{
|
|
struct vlan_tag *tag;
|
|
|
|
/*
|
|
* Move everything in the header, except the type field,
|
|
* down VLAN_TAG_LEN bytes, to allow us to insert the
|
|
* VLAN tag between that stuff and the type field.
|
|
*/
|
|
bp -= VLAN_TAG_LEN;
|
|
memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset);
|
|
|
|
/*
|
|
* Now insert the tag.
|
|
*/
|
|
tag = (struct vlan_tag *)(bp + handlep->vlan_offset);
|
|
tag->vlan_tpid = htons(tp_vlan_tpid);
|
|
tag->vlan_tci = htons(tp_vlan_tci);
|
|
|
|
/*
|
|
* Add the tag to the packet lengths.
|
|
*/
|
|
pcaphdr.caplen += VLAN_TAG_LEN;
|
|
pcaphdr.len += VLAN_TAG_LEN;
|
|
}
|
|
|
|
/*
|
|
* The only way to tell the kernel to cut off the
|
|
* packet at a snapshot length is with a filter program;
|
|
* if there's no filter program, the kernel won't cut
|
|
* the packet off.
|
|
*
|
|
* Trim the snapshot length to be no longer than the
|
|
* specified snapshot length.
|
|
*
|
|
* XXX - an alternative is to put a filter, consisting
|
|
* of a "ret <snaplen>" instruction, on the socket
|
|
* in the activate routine, so that the truncation is
|
|
* done in the kernel even if nobody specified a filter;
|
|
* that means that less buffer space is consumed in
|
|
* the memory-mapped buffer.
|
|
*/
|
|
if (pcaphdr.caplen > (bpf_u_int32)handle->snapshot)
|
|
pcaphdr.caplen = handle->snapshot;
|
|
|
|
/* pass the packet to the user */
|
|
callback(user, &pcaphdr, bp);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
pcap_read_linux_mmap_v2(pcap_t *handle, int max_packets, pcap_handler callback,
|
|
u_char *user)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
union thdr h;
|
|
int pkts = 0;
|
|
int ret;
|
|
|
|
/* wait for frames availability.*/
|
|
h.raw = RING_GET_CURRENT_FRAME(handle);
|
|
if (!packet_mmap_acquire(h.h2)) {
|
|
/*
|
|
* The current frame is owned by the kernel; wait for
|
|
* a frame to be handed to us.
|
|
*/
|
|
ret = pcap_wait_for_frames_mmap(handle);
|
|
if (ret) {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This can conceivably process more than INT_MAX packets,
|
|
* which would overflow the packet count, causing it either
|
|
* to look like a negative number, and thus cause us to
|
|
* return a value that looks like an error, or overflow
|
|
* back into positive territory, and thus cause us to
|
|
* return a too-low count.
|
|
*
|
|
* Therefore, if the packet count is unlimited, we clip
|
|
* it at INT_MAX; this routine is not expected to
|
|
* process packets indefinitely, so that's not an issue.
|
|
*/
|
|
if (PACKET_COUNT_IS_UNLIMITED(max_packets))
|
|
max_packets = INT_MAX;
|
|
|
|
while (pkts < max_packets) {
|
|
/*
|
|
* Get the current ring buffer frame, and break if
|
|
* it's still owned by the kernel.
|
|
*/
|
|
h.raw = RING_GET_CURRENT_FRAME(handle);
|
|
if (!packet_mmap_acquire(h.h2))
|
|
break;
|
|
|
|
ret = pcap_handle_packet_mmap(
|
|
handle,
|
|
callback,
|
|
user,
|
|
h.raw,
|
|
h.h2->tp_len,
|
|
h.h2->tp_mac,
|
|
h.h2->tp_snaplen,
|
|
h.h2->tp_sec,
|
|
handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? h.h2->tp_nsec : h.h2->tp_nsec / 1000,
|
|
VLAN_VALID(h.h2, h.h2),
|
|
h.h2->tp_vlan_tci,
|
|
VLAN_TPID(h.h2, h.h2));
|
|
if (ret == 1) {
|
|
pkts++;
|
|
} else if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Hand this block back to the kernel, and, if we're
|
|
* counting blocks that need to be filtered in userland
|
|
* after having been filtered by the kernel, count
|
|
* the one we've just processed.
|
|
*/
|
|
packet_mmap_release(h.h2);
|
|
if (handlep->blocks_to_filter_in_userland > 0) {
|
|
handlep->blocks_to_filter_in_userland--;
|
|
if (handlep->blocks_to_filter_in_userland == 0) {
|
|
/*
|
|
* No more blocks need to be filtered
|
|
* in userland.
|
|
*/
|
|
handlep->filter_in_userland = 0;
|
|
}
|
|
}
|
|
|
|
/* next block */
|
|
if (++handle->offset >= handle->cc)
|
|
handle->offset = 0;
|
|
|
|
/* check for break loop condition*/
|
|
if (handle->break_loop) {
|
|
handle->break_loop = 0;
|
|
return PCAP_ERROR_BREAK;
|
|
}
|
|
}
|
|
return pkts;
|
|
}
|
|
|
|
#ifdef HAVE_TPACKET3
|
|
static int
|
|
pcap_read_linux_mmap_v3(pcap_t *handle, int max_packets, pcap_handler callback,
|
|
u_char *user)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
union thdr h;
|
|
int pkts = 0;
|
|
int ret;
|
|
|
|
again:
|
|
if (handlep->current_packet == NULL) {
|
|
/* wait for frames availability.*/
|
|
h.raw = RING_GET_CURRENT_FRAME(handle);
|
|
if (!packet_mmap_v3_acquire(h.h3)) {
|
|
/*
|
|
* The current frame is owned by the kernel; wait
|
|
* for a frame to be handed to us.
|
|
*/
|
|
ret = pcap_wait_for_frames_mmap(handle);
|
|
if (ret) {
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
h.raw = RING_GET_CURRENT_FRAME(handle);
|
|
if (!packet_mmap_v3_acquire(h.h3)) {
|
|
if (pkts == 0 && handlep->timeout == 0) {
|
|
/* Block until we see a packet. */
|
|
goto again;
|
|
}
|
|
return pkts;
|
|
}
|
|
|
|
/*
|
|
* This can conceivably process more than INT_MAX packets,
|
|
* which would overflow the packet count, causing it either
|
|
* to look like a negative number, and thus cause us to
|
|
* return a value that looks like an error, or overflow
|
|
* back into positive territory, and thus cause us to
|
|
* return a too-low count.
|
|
*
|
|
* Therefore, if the packet count is unlimited, we clip
|
|
* it at INT_MAX; this routine is not expected to
|
|
* process packets indefinitely, so that's not an issue.
|
|
*/
|
|
if (PACKET_COUNT_IS_UNLIMITED(max_packets))
|
|
max_packets = INT_MAX;
|
|
|
|
while (pkts < max_packets) {
|
|
int packets_to_read;
|
|
|
|
if (handlep->current_packet == NULL) {
|
|
h.raw = RING_GET_CURRENT_FRAME(handle);
|
|
if (!packet_mmap_v3_acquire(h.h3))
|
|
break;
|
|
|
|
handlep->current_packet = h.raw + h.h3->hdr.bh1.offset_to_first_pkt;
|
|
handlep->packets_left = h.h3->hdr.bh1.num_pkts;
|
|
}
|
|
packets_to_read = handlep->packets_left;
|
|
|
|
if (packets_to_read > (max_packets - pkts)) {
|
|
/*
|
|
* There are more packets in the buffer than
|
|
* the number of packets we have left to
|
|
* process to get up to the maximum number
|
|
* of packets to process. Only process enough
|
|
* of them to get us up to that maximum.
|
|
*/
|
|
packets_to_read = max_packets - pkts;
|
|
}
|
|
|
|
while (packets_to_read-- && !handle->break_loop) {
|
|
struct tpacket3_hdr* tp3_hdr = (struct tpacket3_hdr*) handlep->current_packet;
|
|
ret = pcap_handle_packet_mmap(
|
|
handle,
|
|
callback,
|
|
user,
|
|
handlep->current_packet,
|
|
tp3_hdr->tp_len,
|
|
tp3_hdr->tp_mac,
|
|
tp3_hdr->tp_snaplen,
|
|
tp3_hdr->tp_sec,
|
|
handle->opt.tstamp_precision == PCAP_TSTAMP_PRECISION_NANO ? tp3_hdr->tp_nsec : tp3_hdr->tp_nsec / 1000,
|
|
VLAN_VALID(tp3_hdr, &tp3_hdr->hv1),
|
|
tp3_hdr->hv1.tp_vlan_tci,
|
|
VLAN_TPID(tp3_hdr, &tp3_hdr->hv1));
|
|
if (ret == 1) {
|
|
pkts++;
|
|
} else if (ret < 0) {
|
|
handlep->current_packet = NULL;
|
|
return ret;
|
|
}
|
|
handlep->current_packet += tp3_hdr->tp_next_offset;
|
|
handlep->packets_left--;
|
|
}
|
|
|
|
if (handlep->packets_left <= 0) {
|
|
/*
|
|
* Hand this block back to the kernel, and, if
|
|
* we're counting blocks that need to be
|
|
* filtered in userland after having been
|
|
* filtered by the kernel, count the one we've
|
|
* just processed.
|
|
*/
|
|
packet_mmap_v3_release(h.h3);
|
|
if (handlep->blocks_to_filter_in_userland > 0) {
|
|
handlep->blocks_to_filter_in_userland--;
|
|
if (handlep->blocks_to_filter_in_userland == 0) {
|
|
/*
|
|
* No more blocks need to be filtered
|
|
* in userland.
|
|
*/
|
|
handlep->filter_in_userland = 0;
|
|
}
|
|
}
|
|
|
|
/* next block */
|
|
if (++handle->offset >= handle->cc)
|
|
handle->offset = 0;
|
|
|
|
handlep->current_packet = NULL;
|
|
}
|
|
|
|
/* check for break loop condition*/
|
|
if (handle->break_loop) {
|
|
handle->break_loop = 0;
|
|
return PCAP_ERROR_BREAK;
|
|
}
|
|
}
|
|
if (pkts == 0 && handlep->timeout == 0) {
|
|
/* Block until we see a packet. */
|
|
goto again;
|
|
}
|
|
return pkts;
|
|
}
|
|
#endif /* HAVE_TPACKET3 */
|
|
|
|
/*
|
|
* Attach the given BPF code to the packet capture device.
|
|
*/
|
|
static int
|
|
pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter)
|
|
{
|
|
struct pcap_linux *handlep;
|
|
struct sock_fprog fcode;
|
|
int can_filter_in_kernel;
|
|
int err = 0;
|
|
int n, offset;
|
|
|
|
if (!handle)
|
|
return -1;
|
|
if (!filter) {
|
|
pcap_strlcpy(handle->errbuf, "setfilter: No filter specified",
|
|
PCAP_ERRBUF_SIZE);
|
|
return -1;
|
|
}
|
|
|
|
handlep = handle->priv;
|
|
|
|
/* Make our private copy of the filter */
|
|
|
|
if (install_bpf_program(handle, filter) < 0)
|
|
/* install_bpf_program() filled in errbuf */
|
|
return -1;
|
|
|
|
/*
|
|
* Run user level packet filter by default. Will be overridden if
|
|
* installing a kernel filter succeeds.
|
|
*/
|
|
handlep->filter_in_userland = 1;
|
|
|
|
/* Install kernel level filter if possible */
|
|
|
|
#ifdef USHRT_MAX
|
|
if (handle->fcode.bf_len > USHRT_MAX) {
|
|
/*
|
|
* fcode.len is an unsigned short for current kernel.
|
|
* I have yet to see BPF-Code with that much
|
|
* instructions but still it is possible. So for the
|
|
* sake of correctness I added this check.
|
|
*/
|
|
fprintf(stderr, "Warning: Filter too complex for kernel\n");
|
|
fcode.len = 0;
|
|
fcode.filter = NULL;
|
|
can_filter_in_kernel = 0;
|
|
} else
|
|
#endif /* USHRT_MAX */
|
|
{
|
|
/*
|
|
* Oh joy, the Linux kernel uses struct sock_fprog instead
|
|
* of struct bpf_program and of course the length field is
|
|
* of different size. Pointed out by Sebastian
|
|
*
|
|
* Oh, and we also need to fix it up so that all "ret"
|
|
* instructions with non-zero operands have MAXIMUM_SNAPLEN
|
|
* as the operand if we're not capturing in memory-mapped
|
|
* mode, and so that, if we're in cooked mode, all memory-
|
|
* reference instructions use special magic offsets in
|
|
* references to the link-layer header and assume that the
|
|
* link-layer payload begins at 0; "fix_program()" will do
|
|
* that.
|
|
*/
|
|
switch (fix_program(handle, &fcode)) {
|
|
|
|
case -1:
|
|
default:
|
|
/*
|
|
* Fatal error; just quit.
|
|
* (The "default" case shouldn't happen; we
|
|
* return -1 for that reason.)
|
|
*/
|
|
return -1;
|
|
|
|
case 0:
|
|
/*
|
|
* The program performed checks that we can't make
|
|
* work in the kernel.
|
|
*/
|
|
can_filter_in_kernel = 0;
|
|
break;
|
|
|
|
case 1:
|
|
/*
|
|
* We have a filter that'll work in the kernel.
|
|
*/
|
|
can_filter_in_kernel = 1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* NOTE: at this point, we've set both the "len" and "filter"
|
|
* fields of "fcode". As of the 2.6.32.4 kernel, at least,
|
|
* those are the only members of the "sock_fprog" structure,
|
|
* so we initialize every member of that structure.
|
|
*
|
|
* If there is anything in "fcode" that is not initialized,
|
|
* it is either a field added in a later kernel, or it's
|
|
* padding.
|
|
*
|
|
* If a new field is added, this code needs to be updated
|
|
* to set it correctly.
|
|
*
|
|
* If there are no other fields, then:
|
|
*
|
|
* if the Linux kernel looks at the padding, it's
|
|
* buggy;
|
|
*
|
|
* if the Linux kernel doesn't look at the padding,
|
|
* then if some tool complains that we're passing
|
|
* uninitialized data to the kernel, then the tool
|
|
* is buggy and needs to understand that it's just
|
|
* padding.
|
|
*/
|
|
if (can_filter_in_kernel) {
|
|
if ((err = set_kernel_filter(handle, &fcode)) == 0)
|
|
{
|
|
/*
|
|
* Installation succeeded - using kernel filter,
|
|
* so userland filtering not needed.
|
|
*/
|
|
handlep->filter_in_userland = 0;
|
|
}
|
|
else if (err == -1) /* Non-fatal error */
|
|
{
|
|
/*
|
|
* Print a warning if we weren't able to install
|
|
* the filter for a reason other than "this kernel
|
|
* isn't configured to support socket filters.
|
|
*/
|
|
if (errno == ENOMEM) {
|
|
/*
|
|
* Either a kernel memory allocation
|
|
* failure occurred, or there's too
|
|
* much "other/option memory" allocated
|
|
* for this socket. Suggest that they
|
|
* increase the "other/option memory"
|
|
* limit.
|
|
*/
|
|
fprintf(stderr,
|
|
"Warning: Couldn't allocate kernel memory for filter: try increasing net.core.optmem_max with sysctl\n");
|
|
} else if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) {
|
|
fprintf(stderr,
|
|
"Warning: Kernel filter failed: %s\n",
|
|
pcap_strerror(errno));
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we're not using the kernel filter, get rid of any kernel
|
|
* filter that might've been there before, e.g. because the
|
|
* previous filter could work in the kernel, or because some other
|
|
* code attached a filter to the socket by some means other than
|
|
* calling "pcap_setfilter()". Otherwise, the kernel filter may
|
|
* filter out packets that would pass the new userland filter.
|
|
*/
|
|
if (handlep->filter_in_userland) {
|
|
if (reset_kernel_filter(handle) == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"can't remove kernel filter");
|
|
err = -2; /* fatal error */
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Free up the copy of the filter that was made by "fix_program()".
|
|
*/
|
|
if (fcode.filter != NULL)
|
|
free(fcode.filter);
|
|
|
|
if (err == -2)
|
|
/* Fatal error */
|
|
return -1;
|
|
|
|
/*
|
|
* If we're filtering in userland, there's nothing to do;
|
|
* the new filter will be used for the next packet.
|
|
*/
|
|
if (handlep->filter_in_userland)
|
|
return 0;
|
|
|
|
/*
|
|
* We're filtering in the kernel; the packets present in
|
|
* all blocks currently in the ring were already filtered
|
|
* by the old filter, and so will need to be filtered in
|
|
* userland by the new filter.
|
|
*
|
|
* Get an upper bound for the number of such blocks; first,
|
|
* walk the ring backward and count the free blocks.
|
|
*/
|
|
offset = handle->offset;
|
|
if (--offset < 0)
|
|
offset = handle->cc - 1;
|
|
for (n=0; n < handle->cc; ++n) {
|
|
if (--offset < 0)
|
|
offset = handle->cc - 1;
|
|
if (pcap_get_ring_frame_status(handle, offset) != TP_STATUS_KERNEL)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* If we found free blocks, decrement the count of free
|
|
* blocks by 1, just in case we lost a race with another
|
|
* thread of control that was adding a packet while
|
|
* we were counting and that had run the filter before
|
|
* we changed it.
|
|
*
|
|
* XXX - could there be more than one block added in
|
|
* this fashion?
|
|
*
|
|
* XXX - is there a way to avoid that race, e.g. somehow
|
|
* wait for all packets that passed the old filter to
|
|
* be added to the ring?
|
|
*/
|
|
if (n != 0)
|
|
n--;
|
|
|
|
/*
|
|
* Set the count of blocks worth of packets to filter
|
|
* in userland to the total number of blocks in the
|
|
* ring minus the number of free blocks we found, and
|
|
* turn on userland filtering. (The count of blocks
|
|
* worth of packets to filter in userland is guaranteed
|
|
* not to be zero - n, above, couldn't be set to a
|
|
* value > handle->cc, and if it were equal to
|
|
* handle->cc, it wouldn't be zero, and thus would
|
|
* be decremented to handle->cc - 1.)
|
|
*/
|
|
handlep->blocks_to_filter_in_userland = handle->cc - n;
|
|
handlep->filter_in_userland = 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Return the index of the given device name. Fill ebuf and return
|
|
* -1 on failure.
|
|
*/
|
|
static int
|
|
iface_get_id(int fd, const char *device, char *ebuf)
|
|
{
|
|
struct ifreq ifr;
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
|
|
if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) {
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "SIOCGIFINDEX");
|
|
return -1;
|
|
}
|
|
|
|
return ifr.ifr_ifindex;
|
|
}
|
|
|
|
/*
|
|
* Bind the socket associated with FD to the given device.
|
|
* Return 0 on success or a PCAP_ERROR_ value on a hard error.
|
|
*/
|
|
static int
|
|
iface_bind(int fd, int ifindex, char *ebuf, int protocol)
|
|
{
|
|
struct sockaddr_ll sll;
|
|
int ret, err;
|
|
socklen_t errlen = sizeof(err);
|
|
|
|
memset(&sll, 0, sizeof(sll));
|
|
sll.sll_family = AF_PACKET;
|
|
sll.sll_ifindex = ifindex < 0 ? 0 : ifindex;
|
|
sll.sll_protocol = protocol;
|
|
|
|
if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) {
|
|
if (errno == ENETDOWN) {
|
|
/*
|
|
* Return a "network down" indication, so that
|
|
* the application can report that rather than
|
|
* saying we had a mysterious failure and
|
|
* suggest that they report a problem to the
|
|
* libpcap developers.
|
|
*/
|
|
return PCAP_ERROR_IFACE_NOT_UP;
|
|
}
|
|
if (errno == ENODEV) {
|
|
/*
|
|
* There's nothing more to say, so clear the
|
|
* error message.
|
|
*/
|
|
ebuf[0] = '\0';
|
|
ret = PCAP_ERROR_NO_SUCH_DEVICE;
|
|
} else {
|
|
ret = PCAP_ERROR;
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "bind");
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Any pending errors, e.g., network is down? */
|
|
|
|
if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "getsockopt (SO_ERROR)");
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
if (err == ENETDOWN) {
|
|
/*
|
|
* Return a "network down" indication, so that
|
|
* the application can report that rather than
|
|
* saying we had a mysterious failure and
|
|
* suggest that they report a problem to the
|
|
* libpcap developers.
|
|
*/
|
|
return PCAP_ERROR_IFACE_NOT_UP;
|
|
} else if (err > 0) {
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
err, "bind");
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Try to enter monitor mode.
|
|
* If we have libnl, try to create a new monitor-mode device and
|
|
* capture on that; otherwise, just say "not supported".
|
|
*/
|
|
#ifdef HAVE_LIBNL
|
|
static int
|
|
enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
int ret;
|
|
char phydev_path[PATH_MAX+1];
|
|
struct nl80211_state nlstate;
|
|
struct ifreq ifr;
|
|
u_int n;
|
|
|
|
/*
|
|
* Is this a mac80211 device?
|
|
*/
|
|
ret = get_mac80211_phydev(handle, device, phydev_path, PATH_MAX);
|
|
if (ret < 0)
|
|
return ret; /* error */
|
|
if (ret == 0)
|
|
return 0; /* no error, but not mac80211 device */
|
|
|
|
/*
|
|
* XXX - is this already a monN device?
|
|
* If so, we're done.
|
|
*/
|
|
|
|
/*
|
|
* OK, it's apparently a mac80211 device.
|
|
* Try to find an unused monN device for it.
|
|
*/
|
|
ret = nl80211_init(handle, &nlstate, device);
|
|
if (ret != 0)
|
|
return ret;
|
|
for (n = 0; n < UINT_MAX; n++) {
|
|
/*
|
|
* Try mon{n}.
|
|
*/
|
|
char mondevice[3+10+1]; /* mon{UINT_MAX}\0 */
|
|
|
|
snprintf(mondevice, sizeof mondevice, "mon%u", n);
|
|
ret = add_mon_if(handle, sock_fd, &nlstate, device, mondevice);
|
|
if (ret == 1) {
|
|
/*
|
|
* Success. We don't clean up the libnl state
|
|
* yet, as we'll be using it later.
|
|
*/
|
|
goto added;
|
|
}
|
|
if (ret < 0) {
|
|
/*
|
|
* Hard failure. Just return ret; handle->errbuf
|
|
* has already been set.
|
|
*/
|
|
nl80211_cleanup(&nlstate);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: No free monN interfaces", device);
|
|
nl80211_cleanup(&nlstate);
|
|
return PCAP_ERROR;
|
|
|
|
added:
|
|
|
|
#if 0
|
|
/*
|
|
* Sleep for .1 seconds.
|
|
*/
|
|
delay.tv_sec = 0;
|
|
delay.tv_nsec = 500000000;
|
|
nanosleep(&delay, NULL);
|
|
#endif
|
|
|
|
/*
|
|
* If we haven't already done so, arrange to have
|
|
* "pcap_close_all()" called when we exit.
|
|
*/
|
|
if (!pcap_do_addexit(handle)) {
|
|
/*
|
|
* "atexit()" failed; don't put the interface
|
|
* in rfmon mode, just give up.
|
|
*/
|
|
del_mon_if(handle, sock_fd, &nlstate, device,
|
|
handlep->mondevice);
|
|
nl80211_cleanup(&nlstate);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* Now configure the monitor interface up.
|
|
*/
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, handlep->mondevice, sizeof(ifr.ifr_name));
|
|
if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "%s: Can't get flags for %s", device,
|
|
handlep->mondevice);
|
|
del_mon_if(handle, sock_fd, &nlstate, device,
|
|
handlep->mondevice);
|
|
nl80211_cleanup(&nlstate);
|
|
return PCAP_ERROR;
|
|
}
|
|
ifr.ifr_flags |= IFF_UP|IFF_RUNNING;
|
|
if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "%s: Can't set flags for %s", device,
|
|
handlep->mondevice);
|
|
del_mon_if(handle, sock_fd, &nlstate, device,
|
|
handlep->mondevice);
|
|
nl80211_cleanup(&nlstate);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* Success. Clean up the libnl state.
|
|
*/
|
|
nl80211_cleanup(&nlstate);
|
|
|
|
/*
|
|
* Note that we have to delete the monitor device when we close
|
|
* the handle.
|
|
*/
|
|
handlep->must_do_on_close |= MUST_DELETE_MONIF;
|
|
|
|
/*
|
|
* Add this to the list of pcaps to close when we exit.
|
|
*/
|
|
pcap_add_to_pcaps_to_close(handle);
|
|
|
|
return 1;
|
|
}
|
|
#else /* HAVE_LIBNL */
|
|
static int
|
|
enter_rfmon_mode(pcap_t *handle _U_, int sock_fd _U_, const char *device _U_)
|
|
{
|
|
/*
|
|
* We don't have libnl, so we can't do monitor mode.
|
|
*/
|
|
return 0;
|
|
}
|
|
#endif /* HAVE_LIBNL */
|
|
|
|
#if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP)
|
|
/*
|
|
* Map SOF_TIMESTAMPING_ values to PCAP_TSTAMP_ values.
|
|
*/
|
|
static const struct {
|
|
int soft_timestamping_val;
|
|
int pcap_tstamp_val;
|
|
} sof_ts_type_map[3] = {
|
|
{ SOF_TIMESTAMPING_SOFTWARE, PCAP_TSTAMP_HOST },
|
|
{ SOF_TIMESTAMPING_SYS_HARDWARE, PCAP_TSTAMP_ADAPTER },
|
|
{ SOF_TIMESTAMPING_RAW_HARDWARE, PCAP_TSTAMP_ADAPTER_UNSYNCED }
|
|
};
|
|
#define NUM_SOF_TIMESTAMPING_TYPES (sizeof sof_ts_type_map / sizeof sof_ts_type_map[0])
|
|
|
|
/*
|
|
* Set the list of time stamping types to include all types.
|
|
*/
|
|
static int
|
|
iface_set_all_ts_types(pcap_t *handle, char *ebuf)
|
|
{
|
|
u_int i;
|
|
|
|
handle->tstamp_type_list = malloc(NUM_SOF_TIMESTAMPING_TYPES * sizeof(u_int));
|
|
if (handle->tstamp_type_list == NULL) {
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "malloc");
|
|
return -1;
|
|
}
|
|
for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++)
|
|
handle->tstamp_type_list[i] = sof_ts_type_map[i].pcap_tstamp_val;
|
|
handle->tstamp_type_count = NUM_SOF_TIMESTAMPING_TYPES;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Get a list of time stamp types.
|
|
*/
|
|
#ifdef ETHTOOL_GET_TS_INFO
|
|
static int
|
|
iface_get_ts_types(const char *device, pcap_t *handle, char *ebuf)
|
|
{
|
|
int fd;
|
|
struct ifreq ifr;
|
|
struct ethtool_ts_info info;
|
|
int num_ts_types;
|
|
u_int i, j;
|
|
|
|
/*
|
|
* This doesn't apply to the "any" device; you can't say "turn on
|
|
* hardware time stamping for all devices that exist now and arrange
|
|
* that it be turned on for any device that appears in the future",
|
|
* and not all devices even necessarily *support* hardware time
|
|
* stamping, so don't report any time stamp types.
|
|
*/
|
|
if (strcmp(device, "any") == 0) {
|
|
handle->tstamp_type_list = NULL;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Create a socket from which to fetch time stamping capabilities.
|
|
*/
|
|
fd = get_if_ioctl_socket();
|
|
if (fd < 0) {
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "socket for SIOCETHTOOL(ETHTOOL_GET_TS_INFO)");
|
|
return -1;
|
|
}
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
memset(&info, 0, sizeof(info));
|
|
info.cmd = ETHTOOL_GET_TS_INFO;
|
|
ifr.ifr_data = (caddr_t)&info;
|
|
if (ioctl(fd, SIOCETHTOOL, &ifr) == -1) {
|
|
int save_errno = errno;
|
|
|
|
close(fd);
|
|
switch (save_errno) {
|
|
|
|
case EOPNOTSUPP:
|
|
case EINVAL:
|
|
/*
|
|
* OK, this OS version or driver doesn't support
|
|
* asking for the time stamping types, so let's
|
|
* just return all the possible types.
|
|
*/
|
|
if (iface_set_all_ts_types(handle, ebuf) == -1)
|
|
return -1;
|
|
return 0;
|
|
|
|
case ENODEV:
|
|
/*
|
|
* OK, no such device.
|
|
* The user will find that out when they try to
|
|
* activate the device; just return an empty
|
|
* list of time stamp types.
|
|
*/
|
|
handle->tstamp_type_list = NULL;
|
|
return 0;
|
|
|
|
default:
|
|
/*
|
|
* Other error.
|
|
*/
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
save_errno,
|
|
"%s: SIOCETHTOOL(ETHTOOL_GET_TS_INFO) ioctl failed",
|
|
device);
|
|
return -1;
|
|
}
|
|
}
|
|
close(fd);
|
|
|
|
/*
|
|
* Do we support hardware time stamping of *all* packets?
|
|
*/
|
|
if (!(info.rx_filters & (1 << HWTSTAMP_FILTER_ALL))) {
|
|
/*
|
|
* No, so don't report any time stamp types.
|
|
*
|
|
* XXX - some devices either don't report
|
|
* HWTSTAMP_FILTER_ALL when they do support it, or
|
|
* report HWTSTAMP_FILTER_ALL but map it to only
|
|
* time stamping a few PTP packets. See
|
|
* http://marc.info/?l=linux-netdev&m=146318183529571&w=2
|
|
*
|
|
* Maybe that got fixed later.
|
|
*/
|
|
handle->tstamp_type_list = NULL;
|
|
return 0;
|
|
}
|
|
|
|
num_ts_types = 0;
|
|
for (i = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
|
|
if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val)
|
|
num_ts_types++;
|
|
}
|
|
if (num_ts_types != 0) {
|
|
handle->tstamp_type_list = malloc(num_ts_types * sizeof(u_int));
|
|
if (handle->tstamp_type_list == NULL) {
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "malloc");
|
|
return -1;
|
|
}
|
|
for (i = 0, j = 0; i < NUM_SOF_TIMESTAMPING_TYPES; i++) {
|
|
if (info.so_timestamping & sof_ts_type_map[i].soft_timestamping_val) {
|
|
handle->tstamp_type_list[j] = sof_ts_type_map[i].pcap_tstamp_val;
|
|
j++;
|
|
}
|
|
}
|
|
handle->tstamp_type_count = num_ts_types;
|
|
} else
|
|
handle->tstamp_type_list = NULL;
|
|
|
|
return 0;
|
|
}
|
|
#else /* ETHTOOL_GET_TS_INFO */
|
|
static int
|
|
iface_get_ts_types(const char *device, pcap_t *handle, char *ebuf)
|
|
{
|
|
/*
|
|
* This doesn't apply to the "any" device; you can't say "turn on
|
|
* hardware time stamping for all devices that exist now and arrange
|
|
* that it be turned on for any device that appears in the future",
|
|
* and not all devices even necessarily *support* hardware time
|
|
* stamping, so don't report any time stamp types.
|
|
*/
|
|
if (strcmp(device, "any") == 0) {
|
|
handle->tstamp_type_list = NULL;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* We don't have an ioctl to use to ask what's supported,
|
|
* so say we support everything.
|
|
*/
|
|
if (iface_set_all_ts_types(handle, ebuf) == -1)
|
|
return -1;
|
|
return 0;
|
|
}
|
|
#endif /* ETHTOOL_GET_TS_INFO */
|
|
#else /* defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP) */
|
|
static int
|
|
iface_get_ts_types(const char *device _U_, pcap_t *p _U_, char *ebuf _U_)
|
|
{
|
|
/*
|
|
* Nothing to fetch, so it always "succeeds".
|
|
*/
|
|
return 0;
|
|
}
|
|
#endif /* defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP) */
|
|
|
|
/*
|
|
* Find out if we have any form of fragmentation/reassembly offloading.
|
|
*
|
|
* We do so using SIOCETHTOOL checking for various types of offloading;
|
|
* if SIOCETHTOOL isn't defined, or we don't have any #defines for any
|
|
* of the types of offloading, there's nothing we can do to check, so
|
|
* we just say "no, we don't".
|
|
*
|
|
* We treat EOPNOTSUPP, EINVAL and, if eperm_ok is true, EPERM as
|
|
* indications that the operation isn't supported. We do EPERM
|
|
* weirdly because the SIOCETHTOOL code in later kernels 1) doesn't
|
|
* support ETHTOOL_GUFO, 2) also doesn't include it in the list
|
|
* of ethtool operations that don't require CAP_NET_ADMIN privileges,
|
|
* and 3) does the "is this permitted" check before doing the "is
|
|
* this even supported" check, so it fails with "this is not permitted"
|
|
* rather than "this is not even supported". To work around this
|
|
* annoyance, we only treat EPERM as an error for the first feature,
|
|
* and assume that they all do the same permission checks, so if the
|
|
* first one is allowed all the others are allowed if supported.
|
|
*/
|
|
#if defined(SIOCETHTOOL) && (defined(ETHTOOL_GTSO) || defined(ETHTOOL_GUFO) || defined(ETHTOOL_GGSO) || defined(ETHTOOL_GFLAGS) || defined(ETHTOOL_GGRO))
|
|
static int
|
|
iface_ethtool_flag_ioctl(pcap_t *handle, int cmd, const char *cmdname,
|
|
int eperm_ok)
|
|
{
|
|
struct ifreq ifr;
|
|
struct ethtool_value eval;
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, handle->opt.device, sizeof(ifr.ifr_name));
|
|
eval.cmd = cmd;
|
|
eval.data = 0;
|
|
ifr.ifr_data = (caddr_t)&eval;
|
|
if (ioctl(handle->fd, SIOCETHTOOL, &ifr) == -1) {
|
|
if (errno == EOPNOTSUPP || errno == EINVAL ||
|
|
(errno == EPERM && eperm_ok)) {
|
|
/*
|
|
* OK, let's just return 0, which, in our
|
|
* case, either means "no, what we're asking
|
|
* about is not enabled" or "all the flags
|
|
* are clear (i.e., nothing is enabled)".
|
|
*/
|
|
return 0;
|
|
}
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "%s: SIOCETHTOOL(%s) ioctl failed",
|
|
handle->opt.device, cmdname);
|
|
return -1;
|
|
}
|
|
return eval.data;
|
|
}
|
|
|
|
/*
|
|
* XXX - it's annoying that we have to check for offloading at all, but,
|
|
* given that we have to, it's still annoying that we have to check for
|
|
* particular types of offloading, especially that shiny new types of
|
|
* offloading may be added - and, worse, may not be checkable with
|
|
* a particular ETHTOOL_ operation; ETHTOOL_GFEATURES would, in
|
|
* theory, give those to you, but the actual flags being used are
|
|
* opaque (defined in a non-uapi header), and there doesn't seem to
|
|
* be any obvious way to ask the kernel what all the offloading flags
|
|
* are - at best, you can ask for a set of strings(!) to get *names*
|
|
* for various flags. (That whole mechanism appears to have been
|
|
* designed for the sole purpose of letting ethtool report flags
|
|
* by name and set flags by name, with the names having no semantics
|
|
* ethtool understands.)
|
|
*/
|
|
static int
|
|
iface_get_offload(pcap_t *handle)
|
|
{
|
|
int ret;
|
|
|
|
#ifdef ETHTOOL_GTSO
|
|
ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GTSO, "ETHTOOL_GTSO", 0);
|
|
if (ret == -1)
|
|
return -1;
|
|
if (ret)
|
|
return 1; /* TCP segmentation offloading on */
|
|
#endif
|
|
|
|
#ifdef ETHTOOL_GGSO
|
|
/*
|
|
* XXX - will this cause large unsegmented packets to be
|
|
* handed to PF_PACKET sockets on transmission? If not,
|
|
* this need not be checked.
|
|
*/
|
|
ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGSO, "ETHTOOL_GGSO", 0);
|
|
if (ret == -1)
|
|
return -1;
|
|
if (ret)
|
|
return 1; /* generic segmentation offloading on */
|
|
#endif
|
|
|
|
#ifdef ETHTOOL_GFLAGS
|
|
ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GFLAGS, "ETHTOOL_GFLAGS", 0);
|
|
if (ret == -1)
|
|
return -1;
|
|
if (ret & ETH_FLAG_LRO)
|
|
return 1; /* large receive offloading on */
|
|
#endif
|
|
|
|
#ifdef ETHTOOL_GGRO
|
|
/*
|
|
* XXX - will this cause large reassembled packets to be
|
|
* handed to PF_PACKET sockets on receipt? If not,
|
|
* this need not be checked.
|
|
*/
|
|
ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GGRO, "ETHTOOL_GGRO", 0);
|
|
if (ret == -1)
|
|
return -1;
|
|
if (ret)
|
|
return 1; /* generic (large) receive offloading on */
|
|
#endif
|
|
|
|
#ifdef ETHTOOL_GUFO
|
|
/*
|
|
* Do this one last, as support for it was removed in later
|
|
* kernels, and it fails with EPERM on those kernels rather
|
|
* than with EOPNOTSUPP (see explanation in comment for
|
|
* iface_ethtool_flag_ioctl()).
|
|
*/
|
|
ret = iface_ethtool_flag_ioctl(handle, ETHTOOL_GUFO, "ETHTOOL_GUFO", 1);
|
|
if (ret == -1)
|
|
return -1;
|
|
if (ret)
|
|
return 1; /* UDP fragmentation offloading on */
|
|
#endif
|
|
|
|
return 0;
|
|
}
|
|
#else /* SIOCETHTOOL */
|
|
static int
|
|
iface_get_offload(pcap_t *handle _U_)
|
|
{
|
|
/*
|
|
* XXX - do we need to get this information if we don't
|
|
* have the ethtool ioctls? If so, how do we do that?
|
|
*/
|
|
return 0;
|
|
}
|
|
#endif /* SIOCETHTOOL */
|
|
|
|
static struct dsa_proto {
|
|
const char *name;
|
|
bpf_u_int32 linktype;
|
|
} dsa_protos[] = {
|
|
/*
|
|
* None is special and indicates that the interface does not have
|
|
* any tagging protocol configured, and is therefore a standard
|
|
* Ethernet interface.
|
|
*/
|
|
{ "none", DLT_EN10MB },
|
|
{ "brcm", DLT_DSA_TAG_BRCM },
|
|
{ "brcm-prepend", DLT_DSA_TAG_BRCM_PREPEND },
|
|
{ "dsa", DLT_DSA_TAG_DSA },
|
|
{ "edsa", DLT_DSA_TAG_EDSA },
|
|
};
|
|
|
|
static int
|
|
iface_dsa_get_proto_info(const char *device, pcap_t *handle)
|
|
{
|
|
char *pathstr;
|
|
unsigned int i;
|
|
/*
|
|
* Make this significantly smaller than PCAP_ERRBUF_SIZE;
|
|
* the tag *shouldn't* have some huge long name, and making
|
|
* it smaller keeps newer versions of GCC from whining that
|
|
* the error message if we don't support the tag could
|
|
* overflow the error message buffer.
|
|
*/
|
|
char buf[128];
|
|
ssize_t r;
|
|
int fd;
|
|
|
|
fd = asprintf(&pathstr, "/sys/class/net/%s/dsa/tagging", device);
|
|
if (fd < 0) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
fd, "asprintf");
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
fd = open(pathstr, O_RDONLY);
|
|
free(pathstr);
|
|
/*
|
|
* This is not fatal, kernel >= 4.20 *might* expose this attribute
|
|
*/
|
|
if (fd < 0)
|
|
return 0;
|
|
|
|
r = read(fd, buf, sizeof(buf) - 1);
|
|
if (r <= 0) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "read");
|
|
close(fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
close(fd);
|
|
|
|
/*
|
|
* Buffer should be LF terminated.
|
|
*/
|
|
if (buf[r - 1] == '\n')
|
|
r--;
|
|
buf[r] = '\0';
|
|
|
|
for (i = 0; i < sizeof(dsa_protos) / sizeof(dsa_protos[0]); i++) {
|
|
if (strlen(dsa_protos[i].name) == (size_t)r &&
|
|
strcmp(buf, dsa_protos[i].name) == 0) {
|
|
handle->linktype = dsa_protos[i].linktype;
|
|
switch (dsa_protos[i].linktype) {
|
|
case DLT_EN10MB:
|
|
return 0;
|
|
default:
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"unsupported DSA tag: %s", buf);
|
|
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* Query the kernel for the MTU of the given interface.
|
|
*/
|
|
static int
|
|
iface_get_mtu(int fd, const char *device, char *ebuf)
|
|
{
|
|
struct ifreq ifr;
|
|
|
|
if (!device)
|
|
return BIGGER_THAN_ALL_MTUS;
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
|
|
if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) {
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "SIOCGIFMTU");
|
|
return -1;
|
|
}
|
|
|
|
return ifr.ifr_mtu;
|
|
}
|
|
|
|
/*
|
|
* Get the hardware type of the given interface as ARPHRD_xxx constant.
|
|
*/
|
|
static int
|
|
iface_get_arptype(int fd, const char *device, char *ebuf)
|
|
{
|
|
struct ifreq ifr;
|
|
int ret;
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
pcap_strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
|
|
if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
|
|
if (errno == ENODEV) {
|
|
/*
|
|
* No such device.
|
|
*
|
|
* There's nothing more to say, so clear
|
|
* the error message.
|
|
*/
|
|
ret = PCAP_ERROR_NO_SUCH_DEVICE;
|
|
ebuf[0] = '\0';
|
|
} else {
|
|
ret = PCAP_ERROR;
|
|
pcap_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
|
|
errno, "SIOCGIFHWADDR");
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
return ifr.ifr_hwaddr.sa_family;
|
|
}
|
|
|
|
static int
|
|
fix_program(pcap_t *handle, struct sock_fprog *fcode)
|
|
{
|
|
struct pcap_linux *handlep = handle->priv;
|
|
size_t prog_size;
|
|
register int i;
|
|
register struct bpf_insn *p;
|
|
struct bpf_insn *f;
|
|
int len;
|
|
|
|
/*
|
|
* Make a copy of the filter, and modify that copy if
|
|
* necessary.
|
|
*/
|
|
prog_size = sizeof(*handle->fcode.bf_insns) * handle->fcode.bf_len;
|
|
len = handle->fcode.bf_len;
|
|
f = (struct bpf_insn *)malloc(prog_size);
|
|
if (f == NULL) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
errno, "malloc");
|
|
return -1;
|
|
}
|
|
memcpy(f, handle->fcode.bf_insns, prog_size);
|
|
fcode->len = len;
|
|
fcode->filter = (struct sock_filter *) f;
|
|
|
|
for (i = 0; i < len; ++i) {
|
|
p = &f[i];
|
|
/*
|
|
* What type of instruction is this?
|
|
*/
|
|
switch (BPF_CLASS(p->code)) {
|
|
|
|
case BPF_LD:
|
|
case BPF_LDX:
|
|
/*
|
|
* It's a load instruction; is it loading
|
|
* from the packet?
|
|
*/
|
|
switch (BPF_MODE(p->code)) {
|
|
|
|
case BPF_ABS:
|
|
case BPF_IND:
|
|
case BPF_MSH:
|
|
/*
|
|
* Yes; are we in cooked mode?
|
|
*/
|
|
if (handlep->cooked) {
|
|
/*
|
|
* Yes, so we need to fix this
|
|
* instruction.
|
|
*/
|
|
if (fix_offset(handle, p) < 0) {
|
|
/*
|
|
* We failed to do so.
|
|
* Return 0, so our caller
|
|
* knows to punt to userland.
|
|
*/
|
|
return 0;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
return 1; /* we succeeded */
|
|
}
|
|
|
|
static int
|
|
fix_offset(pcap_t *handle, struct bpf_insn *p)
|
|
{
|
|
/*
|
|
* Existing references to auxiliary data shouldn't be adjusted.
|
|
*
|
|
* Note that SKF_AD_OFF is negative, but p->k is unsigned, so
|
|
* we use >= and cast SKF_AD_OFF to unsigned.
|
|
*/
|
|
if (p->k >= (bpf_u_int32)SKF_AD_OFF)
|
|
return 0;
|
|
if (handle->linktype == DLT_LINUX_SLL2) {
|
|
/*
|
|
* What's the offset?
|
|
*/
|
|
if (p->k >= SLL2_HDR_LEN) {
|
|
/*
|
|
* It's within the link-layer payload; that starts
|
|
* at an offset of 0, as far as the kernel packet
|
|
* filter is concerned, so subtract the length of
|
|
* the link-layer header.
|
|
*/
|
|
p->k -= SLL2_HDR_LEN;
|
|
} else if (p->k == 0) {
|
|
/*
|
|
* It's the protocol field; map it to the
|
|
* special magic kernel offset for that field.
|
|
*/
|
|
p->k = SKF_AD_OFF + SKF_AD_PROTOCOL;
|
|
} else if (p->k == 4) {
|
|
/*
|
|
* It's the ifindex field; map it to the
|
|
* special magic kernel offset for that field.
|
|
*/
|
|
p->k = SKF_AD_OFF + SKF_AD_IFINDEX;
|
|
} else if (p->k == 10) {
|
|
/*
|
|
* It's the packet type field; map it to the
|
|
* special magic kernel offset for that field.
|
|
*/
|
|
p->k = SKF_AD_OFF + SKF_AD_PKTTYPE;
|
|
} else if ((bpf_int32)(p->k) > 0) {
|
|
/*
|
|
* It's within the header, but it's not one of
|
|
* those fields; we can't do that in the kernel,
|
|
* so punt to userland.
|
|
*/
|
|
return -1;
|
|
}
|
|
} else {
|
|
/*
|
|
* What's the offset?
|
|
*/
|
|
if (p->k >= SLL_HDR_LEN) {
|
|
/*
|
|
* It's within the link-layer payload; that starts
|
|
* at an offset of 0, as far as the kernel packet
|
|
* filter is concerned, so subtract the length of
|
|
* the link-layer header.
|
|
*/
|
|
p->k -= SLL_HDR_LEN;
|
|
} else if (p->k == 0) {
|
|
/*
|
|
* It's the packet type field; map it to the
|
|
* special magic kernel offset for that field.
|
|
*/
|
|
p->k = SKF_AD_OFF + SKF_AD_PKTTYPE;
|
|
} else if (p->k == 14) {
|
|
/*
|
|
* It's the protocol field; map it to the
|
|
* special magic kernel offset for that field.
|
|
*/
|
|
p->k = SKF_AD_OFF + SKF_AD_PROTOCOL;
|
|
} else if ((bpf_int32)(p->k) > 0) {
|
|
/*
|
|
* It's within the header, but it's not one of
|
|
* those fields; we can't do that in the kernel,
|
|
* so punt to userland.
|
|
*/
|
|
return -1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode)
|
|
{
|
|
int total_filter_on = 0;
|
|
int save_mode;
|
|
int ret;
|
|
int save_errno;
|
|
|
|
/*
|
|
* The socket filter code doesn't discard all packets queued
|
|
* up on the socket when the filter is changed; this means
|
|
* that packets that don't match the new filter may show up
|
|
* after the new filter is put onto the socket, if those
|
|
* packets haven't yet been read.
|
|
*
|
|
* This means, for example, that if you do a tcpdump capture
|
|
* with a filter, the first few packets in the capture might
|
|
* be packets that wouldn't have passed the filter.
|
|
*
|
|
* We therefore discard all packets queued up on the socket
|
|
* when setting a kernel filter. (This isn't an issue for
|
|
* userland filters, as the userland filtering is done after
|
|
* packets are queued up.)
|
|
*
|
|
* To flush those packets, we put the socket in read-only mode,
|
|
* and read packets from the socket until there are no more to
|
|
* read.
|
|
*
|
|
* In order to keep that from being an infinite loop - i.e.,
|
|
* to keep more packets from arriving while we're draining
|
|
* the queue - we put the "total filter", which is a filter
|
|
* that rejects all packets, onto the socket before draining
|
|
* the queue.
|
|
*
|
|
* This code deliberately ignores any errors, so that you may
|
|
* get bogus packets if an error occurs, rather than having
|
|
* the filtering done in userland even if it could have been
|
|
* done in the kernel.
|
|
*/
|
|
if (setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
|
|
&total_fcode, sizeof(total_fcode)) == 0) {
|
|
char drain[1];
|
|
|
|
/*
|
|
* Note that we've put the total filter onto the socket.
|
|
*/
|
|
total_filter_on = 1;
|
|
|
|
/*
|
|
* Save the socket's current mode, and put it in
|
|
* non-blocking mode; we drain it by reading packets
|
|
* until we get an error (which is normally a
|
|
* "nothing more to be read" error).
|
|
*/
|
|
save_mode = fcntl(handle->fd, F_GETFL, 0);
|
|
if (save_mode == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"can't get FD flags when changing filter");
|
|
return -2;
|
|
}
|
|
if (fcntl(handle->fd, F_SETFL, save_mode | O_NONBLOCK) < 0) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"can't set nonblocking mode when changing filter");
|
|
return -2;
|
|
}
|
|
while (recv(handle->fd, &drain, sizeof drain, MSG_TRUNC) >= 0)
|
|
;
|
|
save_errno = errno;
|
|
if (save_errno != EAGAIN) {
|
|
/*
|
|
* Fatal error.
|
|
*
|
|
* If we can't restore the mode or reset the
|
|
* kernel filter, there's nothing we can do.
|
|
*/
|
|
(void)fcntl(handle->fd, F_SETFL, save_mode);
|
|
(void)reset_kernel_filter(handle);
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, save_errno,
|
|
"recv failed when changing filter");
|
|
return -2;
|
|
}
|
|
if (fcntl(handle->fd, F_SETFL, save_mode) == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"can't restore FD flags when changing filter");
|
|
return -2;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Now attach the new filter.
|
|
*/
|
|
ret = setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER,
|
|
fcode, sizeof(*fcode));
|
|
if (ret == -1 && total_filter_on) {
|
|
/*
|
|
* Well, we couldn't set that filter on the socket,
|
|
* but we could set the total filter on the socket.
|
|
*
|
|
* This could, for example, mean that the filter was
|
|
* too big to put into the kernel, so we'll have to
|
|
* filter in userland; in any case, we'll be doing
|
|
* filtering in userland, so we need to remove the
|
|
* total filter so we see packets.
|
|
*/
|
|
save_errno = errno;
|
|
|
|
/*
|
|
* If this fails, we're really screwed; we have the
|
|
* total filter on the socket, and it won't come off.
|
|
* Report it as a fatal error.
|
|
*/
|
|
if (reset_kernel_filter(handle) == -1) {
|
|
pcap_fmt_errmsg_for_errno(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE, errno,
|
|
"can't remove kernel total filter");
|
|
return -2; /* fatal error */
|
|
}
|
|
|
|
errno = save_errno;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
reset_kernel_filter(pcap_t *handle)
|
|
{
|
|
int ret;
|
|
/*
|
|
* setsockopt() barfs unless it get a dummy parameter.
|
|
* valgrind whines unless the value is initialized,
|
|
* as it has no idea that setsockopt() ignores its
|
|
* parameter.
|
|
*/
|
|
int dummy = 0;
|
|
|
|
ret = setsockopt(handle->fd, SOL_SOCKET, SO_DETACH_FILTER,
|
|
&dummy, sizeof(dummy));
|
|
/*
|
|
* Ignore ENOENT - it means "we don't have a filter", so there
|
|
* was no filter to remove, and there's still no filter.
|
|
*
|
|
* Also ignore ENONET, as a lot of kernel versions had a
|
|
* typo where ENONET, rather than ENOENT, was returned.
|
|
*/
|
|
if (ret == -1 && errno != ENOENT && errno != ENONET)
|
|
return -1;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
pcap_set_protocol_linux(pcap_t *p, int protocol)
|
|
{
|
|
if (pcap_check_activated(p))
|
|
return (PCAP_ERROR_ACTIVATED);
|
|
p->opt.protocol = protocol;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Libpcap version string.
|
|
*/
|
|
const char *
|
|
pcap_lib_version(void)
|
|
{
|
|
#if defined(HAVE_TPACKET3)
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return (PCAP_VERSION_STRING " (with TPACKET_V3)");
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#else
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return (PCAP_VERSION_STRING " (with TPACKET_V2)");
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#endif
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}
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