e89167f07a
Changes: Thu. April 1, 2010. guy@alum.mit.edu. Summary for 1.1.1 libpcap release Update CHANGES to reflect more of the changes in 1.1.0. Fix build on RHEL5. Fix shared library build on AIX. Thu. March 11, 2010. ken@netfunctional.ca/guy@alum.mit.edu. Summary for 1.1.0 libpcap release Add SocketCAN capture support Add Myricom SNF API support Update Endace DAG and ERF support Add support for shared libraries on Solaris, HP-UX, and AIX Build, install, and un-install shared libraries by default; don't build/install shared libraries on platforms we don't support Fix building from a directory other than the source directory Fix compiler warnings and builds on some platforms Update config.guess and config.sub Support monitor mode on mac80211 devices on Linux Fix USB memory-mapped capturing on Linux; it requires a new DLT_ value On Linux, scan /sys/class/net for devices if we have it; scan it, or /proc/net/dev if we don't have /sys/class/net, even if we have getifaddrs(), as it'll find interfaces with no addresses Add limited support for reading pcap-ng files Fix BPF driver-loading error handling on AIX Support getting the full-length interface description on FreeBSD In the lexical analyzer, free up any addrinfo structure we got back from getaddrinfo(). Add support for BPF and libdlpi in OpenSolaris (and SXCE) Hyphenate "link-layer" everywhere Add /sys/kernel/debug/usb/usbmon to the list of usbmon locations In pcap_read_linux_mmap(), if there are no frames available, call poll() even if we're in non-blocking mode, so we pick up errors, and check for the errors in question. Note that poll() works on BPF devices is Snow Leopard If an ENXIO or ENETDOWN is received, it may mean the device has gone away. Deal with it. For BPF, raise the default capture buffer size to from 32k to 512k Support ps_ifdrop on Linux Added a bunch of #ifdef directives to make wpcap.dll (WinPcap) compile under cygwin. Changes to Linux mmapped captures. Fix bug where create_ring would fail for particular snaplen and buffer size combinations Update pcap-config so that it handles libpcap requiring additional libraries Add workaround for threadsafeness on Windows Add missing mapping for DLT_ENC <-> LINKTYPE_ENC DLT: Add DLT_CAN_SOCKETCAN DLT: Add Solaris ipnet Don't check for DLT_IPNET if it's not defined Add link-layer types for Fibre Channel FC-2 Add link-layer types for Wireless HART Add link-layer types for AOS Add link-layer types for DECT Autoconf fixes (AIX, HP-UX, OSF/1, Tru64 cleanups) Install headers unconditionally, and include vlan.h/bluetooth.h if enabled Autoconf fixes+cleanup Support enabling/disabling bluetooth (--{en,dis}able-bluetooth) Support disabling SITA support (--without-sita) Return -1 on failure to create packet ring (if supported but creation failed) Fix handling of 'any' device, so that it can be opened, and no longer attempt to open it in Monitor mode Add support for snapshot length for USB Memory-Mapped Interface Fix configure and build on recent Linux kernels Fix memory-mapped Linux capture to support pcap_next() and pcap_next_ex() Fixes for Linux USB capture DLT: Add DLT_LINUX_EVDEV DLT: Add DLT_GSMTAP_UM DLT: Add DLT_GSMTAP_ABIS
4864 lines
132 KiB
C
4864 lines
132 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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*
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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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#ifndef lint
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static const char rcsid[] _U_ =
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"@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.164 2008-12-14 22:00:57 guy Exp $ (LBL)";
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#endif
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/*
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* Known problems with 2.0[.x] kernels:
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*
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* - The loopback device gives every packet twice; on 2.2[.x] kernels,
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* if we use PF_PACKET, we can filter out the transmitted version
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* of the packet by using data in the "sockaddr_ll" returned by
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* "recvfrom()", but, on 2.0[.x] kernels, we have to use
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* PF_INET/SOCK_PACKET, which means "recvfrom()" supplies a
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* "sockaddr_pkt" which doesn't give us enough information to let
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* us do that.
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*
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* - We have to set the interface's IFF_PROMISC flag ourselves, if
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* we're to run in promiscuous mode, which means we have to turn
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* it off ourselves when we're done; the kernel doesn't keep track
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* of how many sockets are listening promiscuously, which means
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* it won't get turned off automatically when no sockets are
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* listening promiscuously. We catch "pcap_close()" and, for
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* interfaces we put into promiscuous mode, take them out of
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* promiscuous mode - which isn't necessarily the right thing to
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* do, if another socket also requested promiscuous mode between
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* the time when we opened the socket and the time when we close
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* the socket.
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*
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* - MSG_TRUNC isn't supported, so you can't specify that "recvfrom()"
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* return the amount of data that you could have read, rather than
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* the amount that was returned, so we can't just allocate a buffer
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* whose size is the snapshot length and pass the snapshot length
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* as the byte count, and also pass MSG_TRUNC, so that the return
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* value tells us how long the packet was on the wire.
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*
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* This means that, if we want to get the actual size of the packet,
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* so we can return it in the "len" field of the packet header,
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* we have to read the entire packet, not just the part that fits
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* within the snapshot length, and thus waste CPU time copying data
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* from the kernel that our caller won't see.
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*
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* We have to get the actual size, and supply it in "len", because
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* otherwise, the IP dissector in tcpdump, for example, will complain
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* about "truncated-ip", as the packet will appear to have been
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* shorter, on the wire, than the IP header said it should have been.
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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 <ctype.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/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 <netinet/in.h>
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#include <linux/if_ether.h>
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#include <net/if_arp.h>
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#include <poll.h>
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#include <dirent.h>
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/*
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* Got Wireless Extensions?
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*/
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#ifdef HAVE_LINUX_WIRELESS_H
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#include <linux/wireless.h>
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#endif /* HAVE_LINUX_WIRELESS_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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#include "pcap-int.h"
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#include "pcap/sll.h"
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#include "pcap/vlan.h"
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#ifdef HAVE_DAG_API
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#include "pcap-dag.h"
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#endif /* HAVE_DAG_API */
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#ifdef HAVE_SEPTEL_API
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#include "pcap-septel.h"
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#endif /* HAVE_SEPTEL_API */
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#ifdef HAVE_SNF_API
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#include "pcap-snf.h"
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#endif /* HAVE_SNF_API */
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#ifdef PCAP_SUPPORT_USB
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#include "pcap-usb-linux.h"
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#endif
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#ifdef PCAP_SUPPORT_BT
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#include "pcap-bt-linux.h"
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#endif
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#ifdef PCAP_SUPPORT_CAN
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#include "pcap-can-linux.h"
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#endif
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/*
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* If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET
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* sockets rather than SOCK_PACKET sockets.
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*
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* To use them, we include <linux/if_packet.h> rather than
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* <netpacket/packet.h>; we do so because
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*
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* some Linux distributions (e.g., Slackware 4.0) have 2.2 or
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* later kernels and libc5, and don't provide a <netpacket/packet.h>
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* file;
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*
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* not all versions of glibc2 have a <netpacket/packet.h> file
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* that defines stuff needed for some of the 2.4-or-later-kernel
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* features, so if the system has a 2.4 or later kernel, we
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* still can't use those features.
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*
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* We're already including a number of other <linux/XXX.h> headers, and
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* this code is Linux-specific (no other OS has PF_PACKET sockets as
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* a raw packet capture mechanism), so it's not as if you gain any
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* useful portability by using <netpacket/packet.h>
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*
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* XXX - should we just include <linux/if_packet.h> even if PF_PACKET
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* isn't defined? It only defines one data structure in 2.0.x, so
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* it shouldn't cause any problems.
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*/
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#ifdef PF_PACKET
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# include <linux/if_packet.h>
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/*
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* On at least some Linux distributions (for example, Red Hat 5.2),
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* there's no <netpacket/packet.h> file, but PF_PACKET is defined if
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* you include <sys/socket.h>, but <linux/if_packet.h> doesn't define
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* any of the PF_PACKET stuff such as "struct sockaddr_ll" or any of
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* the PACKET_xxx stuff.
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*
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* So we check whether PACKET_HOST is defined, and assume that we have
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* PF_PACKET sockets only if it is defined.
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*/
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# ifdef PACKET_HOST
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# define HAVE_PF_PACKET_SOCKETS
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# ifdef PACKET_AUXDATA
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# define HAVE_PACKET_AUXDATA
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# endif /* PACKET_AUXDATA */
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# endif /* PACKET_HOST */
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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 TPACKET_HDRLEN
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# define HAVE_PACKET_RING
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# ifdef TPACKET2_HDRLEN
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# define HAVE_TPACKET2
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# else
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# define TPACKET_V1 0
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# endif /* TPACKET2_HDRLEN */
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# endif /* TPACKET_HDRLEN */
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#endif /* PF_PACKET */
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#ifdef SO_ATTACH_FILTER
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#include <linux/types.h>
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#include <linux/filter.h>
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#endif
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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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#ifndef MSG_TRUNC
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/*
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* This is being compiled on a system that lacks MSG_TRUNC; define it
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* with the value it has in the 2.2 and later kernels, so that, on
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* those kernels, when we pass it in the flags argument to "recvfrom()"
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* we're passing the right value and thus get the MSG_TRUNC behavior
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* we want. (We don't get that behavior on 2.0[.x] kernels, because
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* they didn't support MSG_TRUNC.)
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*/
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#define MSG_TRUNC 0x20
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#endif
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#ifndef SOL_PACKET
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/*
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* This is being compiled on a system that lacks SOL_PACKET; define it
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* with the value it has in the 2.2 and later kernels, so that we can
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* set promiscuous mode in the good modern way rather than the old
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* 2.0-kernel crappy way.
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*/
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#define SOL_PACKET 263
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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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* Prototypes for internal functions and methods.
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*/
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static void map_arphrd_to_dlt(pcap_t *, int, int);
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#ifdef HAVE_PF_PACKET_SOCKETS
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static short int map_packet_type_to_sll_type(short int);
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#endif
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static int pcap_activate_linux(pcap_t *);
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static int activate_old(pcap_t *);
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static int activate_new(pcap_t *);
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static int activate_mmap(pcap_t *);
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static int pcap_can_set_rfmon_linux(pcap_t *);
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static int pcap_read_linux(pcap_t *, int, pcap_handler, u_char *);
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static int pcap_read_packet(pcap_t *, pcap_handler, u_char *);
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static int pcap_inject_linux(pcap_t *, const void *, size_t);
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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 void pcap_cleanup_linux(pcap_t *);
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union thdr {
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struct tpacket_hdr *h1;
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struct tpacket2_hdr *h2;
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void *raw;
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};
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#ifdef HAVE_PACKET_RING
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#define RING_GET_FRAME(h) (((union thdr **)h->buffer)[h->offset])
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static void destroy_ring(pcap_t *handle);
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static int create_ring(pcap_t *handle);
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static int prepare_tpacket_socket(pcap_t *handle);
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static void pcap_cleanup_linux_mmap(pcap_t *);
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static int pcap_read_linux_mmap(pcap_t *, int, pcap_handler , u_char *);
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static int pcap_setfilter_linux_mmap(pcap_t *, struct bpf_program *);
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static int pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf);
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static int pcap_getnonblock_mmap(pcap_t *p, char *errbuf);
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static void pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h,
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const u_char *bytes);
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#endif
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/*
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* Wrap some ioctl calls
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*/
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#ifdef HAVE_PF_PACKET_SOCKETS
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static int iface_get_id(int fd, const char *device, char *ebuf);
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#endif
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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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#ifdef HAVE_PF_PACKET_SOCKETS
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static int iface_bind(int fd, int ifindex, char *ebuf);
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#ifdef IW_MODE_MONITOR
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static int has_wext(int sock_fd, const char *device, char *ebuf);
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#endif /* IW_MODE_MONITOR */
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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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#endif /* HAVE_PF_PACKET_SOCKETS */
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static int iface_bind_old(int fd, const char *device, char *ebuf);
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#ifdef SO_ATTACH_FILTER
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static int fix_program(pcap_t *handle, struct sock_fprog *fcode,
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int is_mapped);
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static int fix_offset(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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#endif
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pcap_t *
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pcap_create(const char *device, char *ebuf)
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{
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pcap_t *handle;
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/*
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* A null device name is equivalent to the "any" device.
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*/
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if (device == NULL)
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device = "any";
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#ifdef HAVE_DAG_API
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if (strstr(device, "dag")) {
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return dag_create(device, ebuf);
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}
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#endif /* HAVE_DAG_API */
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#ifdef HAVE_SEPTEL_API
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if (strstr(device, "septel")) {
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return septel_create(device, ebuf);
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}
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#endif /* HAVE_SEPTEL_API */
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#ifdef HAVE_SNF_API
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handle = snf_create(device, ebuf);
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if (strstr(device, "snf") || handle != NULL)
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return handle;
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#endif /* HAVE_SNF_API */
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#ifdef PCAP_SUPPORT_BT
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if (strstr(device, "bluetooth")) {
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return bt_create(device, ebuf);
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}
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#endif
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#ifdef PCAP_SUPPORT_CAN
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if (strstr(device, "can") || strstr(device, "vcan")) {
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return can_create(device, ebuf);
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}
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#endif
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#ifdef PCAP_SUPPORT_USB
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if (strstr(device, "usbmon")) {
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return usb_create(device, ebuf);
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}
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#endif
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handle = pcap_create_common(device, ebuf);
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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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return handle;
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}
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#ifdef HAVE_LIBNL
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/*
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*
|
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* If interface {if} is a mac80211 driver, the file
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* /sys/class/net/{if}/phy80211 is a symlink to
|
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* /sys/class/ieee80211/{phydev}, for some {phydev}.
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*
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* On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
|
|
* least, has a "wmaster0" device and a "wlan0" device; the
|
|
* latter is the one with the IP address. Both show up in
|
|
* "tcpdump -D" output. Capturing on the wmaster0 device
|
|
* captures with 802.11 headers.
|
|
*
|
|
* airmon-ng searches through /sys/class/net for devices named
|
|
* monN, starting with mon0; as soon as one *doesn't* exist,
|
|
* it chooses that as the monitor device name. If the "iw"
|
|
* command exists, it does "iw dev {if} interface add {monif}
|
|
* type monitor", where {monif} is the monitor device. It
|
|
* then (sigh) sleeps .1 second, and then configures the
|
|
* device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
|
|
* is a file, it writes {mondev}, without a newline, to that file,
|
|
* and again (sigh) sleeps .1 second, and then iwconfig's that
|
|
* device into monitor mode and configures it up. Otherwise,
|
|
* you can't do monitor mode.
|
|
*
|
|
* All these devices are "glued" together by having the
|
|
* /sys/class/net/{device}/phy80211 links pointing to the same
|
|
* place, so, given a wmaster, wlan, or mon device, you can
|
|
* find the other devices by looking for devices with
|
|
* the same phy80211 link.
|
|
*
|
|
* To turn monitor mode off, delete the monitor interface,
|
|
* either with "iw dev {monif} interface del" or by sending
|
|
* {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
|
|
*
|
|
* Note: if you try to create a monitor device named "monN", and
|
|
* there's already a "monN" device, it fails, as least with
|
|
* the netlink interface (which is what iw uses), with a return
|
|
* 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;
|
|
}
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: Can't readlink %s: %s", device, pathstr,
|
|
strerror(errno));
|
|
free(pathstr);
|
|
return PCAP_ERROR;
|
|
}
|
|
free(pathstr);
|
|
phydev_path[bytes_read] = '\0';
|
|
return 1;
|
|
}
|
|
|
|
struct nl80211_state {
|
|
struct nl_handle *nl_handle;
|
|
struct nl_cache *nl_cache;
|
|
struct genl_family *nl80211;
|
|
};
|
|
|
|
static int
|
|
nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device)
|
|
{
|
|
state->nl_handle = nl_handle_alloc();
|
|
if (!state->nl_handle) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to allocate netlink handle", device);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
if (genl_connect(state->nl_handle)) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to connect to generic netlink", device);
|
|
goto out_handle_destroy;
|
|
}
|
|
|
|
state->nl_cache = genl_ctrl_alloc_cache(state->nl_handle);
|
|
if (!state->nl_cache) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: failed to allocate generic netlink cache", device);
|
|
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_handle_destroy(state->nl_handle);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
static void
|
|
nl80211_cleanup(struct nl80211_state *state)
|
|
{
|
|
genl_family_put(state->nl80211);
|
|
nl_cache_free(state->nl_cache);
|
|
nl_handle_destroy(state->nl_handle);
|
|
}
|
|
|
|
static int
|
|
add_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, 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);
|
|
NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
|
|
NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);
|
|
|
|
err = nl_send_auto_complete(state->nl_handle, msg);
|
|
if (err < 0) {
|
|
if (err == -ENFILE) {
|
|
/*
|
|
* Device not available; our caller should just
|
|
* keep trying.
|
|
*/
|
|
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, strerror(-err));
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
err = nl_wait_for_ack(state->nl_handle);
|
|
if (err < 0) {
|
|
if (err == -ENFILE) {
|
|
/*
|
|
* Device not available; our caller should just
|
|
* keep trying.
|
|
*/
|
|
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, strerror(-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 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_handle, msg);
|
|
if (err < 0) {
|
|
if (err == -ENFILE) {
|
|
/*
|
|
* Device not available; our caller should just
|
|
* keep trying.
|
|
*/
|
|
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 deleting %s interface: %s",
|
|
device, mondevice, strerror(-err));
|
|
nlmsg_free(msg);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
err = nl_wait_for_ack(state->nl_handle);
|
|
if (err < 0) {
|
|
if (err == -ENFILE) {
|
|
/*
|
|
* Device not available; our caller should just
|
|
* keep trying.
|
|
*/
|
|
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, strerror(-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;
|
|
}
|
|
|
|
static int
|
|
enter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device)
|
|
{
|
|
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.
|
|
* Is that determined by old Wireless Extensions ioctls?
|
|
*/
|
|
|
|
/*
|
|
* 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) {
|
|
handle->md.mondevice = strdup(mondevice);
|
|
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
|
|
|
|
/*
|
|
* Now configure the monitor interface up.
|
|
*/
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
strncpy(ifr.ifr_name, handle->md.mondevice, sizeof(ifr.ifr_name));
|
|
if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: Can't get flags for %s: %s", device,
|
|
handle->md.mondevice, strerror(errno));
|
|
del_mon_if(handle, sock_fd, &nlstate, device,
|
|
handle->md.mondevice);
|
|
nl80211_cleanup(&nlstate);
|
|
return PCAP_ERROR;
|
|
}
|
|
ifr.ifr_flags |= IFF_UP|IFF_RUNNING;
|
|
if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: Can't set flags for %s: %s", device,
|
|
handle->md.mondevice, strerror(errno));
|
|
del_mon_if(handle, sock_fd, &nlstate, device,
|
|
handle->md.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.
|
|
*/
|
|
handle->md.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;
|
|
}
|
|
#endif /* HAVE_LIBNL */
|
|
|
|
static int
|
|
pcap_can_set_rfmon_linux(pcap_t *handle)
|
|
{
|
|
#ifdef HAVE_LIBNL
|
|
char phydev_path[PATH_MAX+1];
|
|
int ret;
|
|
#endif
|
|
#ifdef IW_MODE_MONITOR
|
|
int sock_fd;
|
|
struct iwreq ireq;
|
|
#endif
|
|
|
|
if (strcmp(handle->opt.source, "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.
|
|
*
|
|
* wmaster devices don't appear to support the Wireless
|
|
* Extensions, but we can create a mon device for a
|
|
* wmaster device, so we don't bother checking whether
|
|
* a mac80211 device supports the Wireless Extensions.
|
|
*/
|
|
ret = get_mac80211_phydev(handle, handle->opt.source, phydev_path,
|
|
PATH_MAX);
|
|
if (ret < 0)
|
|
return ret; /* error */
|
|
if (ret == 1)
|
|
return 1; /* mac80211 device */
|
|
#endif
|
|
|
|
#ifdef IW_MODE_MONITOR
|
|
/*
|
|
* Bleah. There doesn't appear to be an ioctl to use to ask
|
|
* whether a device supports monitor mode; we'll just do
|
|
* SIOCGIWMODE and, if it succeeds, assume the device supports
|
|
* monitor mode.
|
|
*
|
|
* Open a socket on which to attempt to get the mode.
|
|
* (We assume that if we have Wireless Extensions support
|
|
* we also have PF_PACKET support.)
|
|
*/
|
|
sock_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
|
|
if (sock_fd == -1) {
|
|
(void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"socket: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* Attempt to get the current mode.
|
|
*/
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, handle->opt.source,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
if (ioctl(sock_fd, SIOCGIWMODE, &ireq) != -1) {
|
|
/*
|
|
* Well, we got the mode; assume we can set it.
|
|
*/
|
|
close(sock_fd);
|
|
return 1;
|
|
}
|
|
if (errno == ENODEV) {
|
|
/* The device doesn't even exist. */
|
|
(void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGIWMODE failed: %s", pcap_strerror(errno));
|
|
close(sock_fd);
|
|
return PCAP_ERROR_NO_SUCH_DEVICE;
|
|
}
|
|
close(sock_fd);
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Grabs the number of dropped packets by the interface from /proc/net/dev.
|
|
*
|
|
* XXX - what about /sys/class/net/{interface name}/rx_*? There are
|
|
* individual devices giving, in ASCII, various rx_ and tx_ statistics.
|
|
*
|
|
* Or can we get them in binary form from netlink?
|
|
*/
|
|
static long int
|
|
linux_if_drops(const char * if_name)
|
|
{
|
|
char buffer[512];
|
|
char * bufptr;
|
|
FILE * file;
|
|
int field_to_convert = 3, if_name_sz = strlen(if_name);
|
|
long int dropped_pkts = 0;
|
|
|
|
file = fopen("/proc/net/dev", "r");
|
|
if (!file)
|
|
return 0;
|
|
|
|
while (!dropped_pkts && fgets( buffer, sizeof(buffer), file ))
|
|
{
|
|
/* search for 'bytes' -- if its in there, then
|
|
that means we need to grab the fourth field. otherwise
|
|
grab the third field. */
|
|
if (field_to_convert != 4 && strstr(buffer, "bytes"))
|
|
{
|
|
field_to_convert = 4;
|
|
continue;
|
|
}
|
|
|
|
/* find iface and make sure it actually matches -- space before the name and : after it */
|
|
if ((bufptr = strstr(buffer, if_name)) &&
|
|
(bufptr == buffer || *(bufptr-1) == ' ') &&
|
|
*(bufptr + if_name_sz) == ':')
|
|
{
|
|
bufptr = bufptr + if_name_sz + 1;
|
|
|
|
/* grab the nth field from it */
|
|
while( --field_to_convert && *bufptr != '\0')
|
|
{
|
|
while (*bufptr != '\0' && *(bufptr++) == ' ');
|
|
while (*bufptr != '\0' && *(bufptr++) != ' ');
|
|
}
|
|
|
|
/* get rid of any final spaces */
|
|
while (*bufptr != '\0' && *bufptr == ' ') bufptr++;
|
|
|
|
if (*bufptr != '\0')
|
|
dropped_pkts = strtol(bufptr, NULL, 10);
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
fclose(file);
|
|
return dropped_pkts;
|
|
}
|
|
|
|
|
|
/*
|
|
* With older kernels promiscuous 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 promiscuous 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 promiscuous mode.
|
|
*
|
|
* Even with newer kernels, we have the same issue with rfmon mode.
|
|
*/
|
|
|
|
static void pcap_cleanup_linux( pcap_t *handle )
|
|
{
|
|
struct ifreq ifr;
|
|
#ifdef HAVE_LIBNL
|
|
struct nl80211_state nlstate;
|
|
int ret;
|
|
#endif /* HAVE_LIBNL */
|
|
#ifdef IW_MODE_MONITOR
|
|
struct iwreq ireq;
|
|
#endif /* IW_MODE_MONITOR */
|
|
|
|
if (handle->md.must_do_on_close != 0) {
|
|
/*
|
|
* There's something we have to do when closing this
|
|
* pcap_t.
|
|
*/
|
|
if (handle->md.must_do_on_close & MUST_CLEAR_PROMISC) {
|
|
/*
|
|
* We put the interface into promiscuous mode;
|
|
* take it out of promiscuous mode.
|
|
*
|
|
* XXX - if somebody else wants it in promiscuous
|
|
* mode, this code cannot know that, so it'll take
|
|
* it out of promiscuous mode. That's not fixable
|
|
* in 2.0[.x] kernels.
|
|
*/
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
strncpy(ifr.ifr_name, handle->md.device,
|
|
sizeof(ifr.ifr_name));
|
|
if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
|
|
fprintf(stderr,
|
|
"Can't restore interface flags (SIOCGIFFLAGS failed: %s).\n"
|
|
"Please adjust manually.\n"
|
|
"Hint: This can't happen with Linux >= 2.2.0.\n",
|
|
strerror(errno));
|
|
} else {
|
|
if (ifr.ifr_flags & IFF_PROMISC) {
|
|
/*
|
|
* Promiscuous mode is currently on;
|
|
* turn it off.
|
|
*/
|
|
ifr.ifr_flags &= ~IFF_PROMISC;
|
|
if (ioctl(handle->fd, SIOCSIFFLAGS,
|
|
&ifr) == -1) {
|
|
fprintf(stderr,
|
|
"Can't restore interface flags (SIOCSIFFLAGS failed: %s).\n"
|
|
"Please adjust manually.\n"
|
|
"Hint: This can't happen with Linux >= 2.2.0.\n",
|
|
strerror(errno));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef HAVE_LIBNL
|
|
if (handle->md.must_do_on_close & MUST_DELETE_MONIF) {
|
|
ret = nl80211_init(handle, &nlstate, handle->md.device);
|
|
if (ret >= 0) {
|
|
ret = del_mon_if(handle, handle->fd, &nlstate,
|
|
handle->md.device, handle->md.mondevice);
|
|
nl80211_cleanup(&nlstate);
|
|
}
|
|
if (ret < 0) {
|
|
fprintf(stderr,
|
|
"Can't delete monitor interface %s (%s).\n"
|
|
"Please delete manually.\n",
|
|
handle->md.mondevice, handle->errbuf);
|
|
}
|
|
}
|
|
#endif /* HAVE_LIBNL */
|
|
|
|
#ifdef IW_MODE_MONITOR
|
|
if (handle->md.must_do_on_close & MUST_CLEAR_RFMON) {
|
|
/*
|
|
* We put the interface into rfmon mode;
|
|
* take it out of rfmon mode.
|
|
*
|
|
* XXX - if somebody else wants it in rfmon
|
|
* mode, this code cannot know that, so it'll take
|
|
* it out of rfmon mode.
|
|
*/
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, handle->md.device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1]
|
|
= 0;
|
|
ireq.u.mode = handle->md.oldmode;
|
|
if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) {
|
|
/*
|
|
* Scientist, you've failed.
|
|
*/
|
|
fprintf(stderr,
|
|
"Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n"
|
|
"Please adjust manually.\n",
|
|
strerror(errno));
|
|
}
|
|
}
|
|
#endif /* IW_MODE_MONITOR */
|
|
|
|
/*
|
|
* 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->md.mondevice != NULL) {
|
|
free(handle->md.mondevice);
|
|
handle->md.mondevice = NULL;
|
|
}
|
|
if (handle->md.device != NULL) {
|
|
free(handle->md.device);
|
|
handle->md.device = NULL;
|
|
}
|
|
pcap_cleanup_live_common(handle);
|
|
}
|
|
|
|
/*
|
|
* 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 promiscous 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)
|
|
{
|
|
const char *device;
|
|
int status = 0;
|
|
|
|
device = handle->opt.source;
|
|
|
|
handle->inject_op = pcap_inject_linux;
|
|
handle->setfilter_op = pcap_setfilter_linux;
|
|
handle->setdirection_op = pcap_setdirection_linux;
|
|
handle->set_datalink_op = NULL; /* can't change data link type */
|
|
handle->getnonblock_op = pcap_getnonblock_fd;
|
|
handle->setnonblock_op = pcap_setnonblock_fd;
|
|
handle->cleanup_op = pcap_cleanup_linux;
|
|
handle->read_op = pcap_read_linux;
|
|
handle->stats_op = pcap_stats_linux;
|
|
|
|
/*
|
|
* The "any" device is a special device which causes us not
|
|
* to bind to a particular device and thus to look at all
|
|
* devices.
|
|
*/
|
|
if (strcmp(device, "any") == 0) {
|
|
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;
|
|
}
|
|
}
|
|
|
|
handle->md.device = strdup(device);
|
|
if (handle->md.device == NULL) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s",
|
|
pcap_strerror(errno) );
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* If we're in promiscuous mode, then we probably want
|
|
* to see when the interface drops packets too, so get an
|
|
* initial count from /proc/net/dev
|
|
*/
|
|
if (handle->opt.promisc)
|
|
handle->md.proc_dropped = linux_if_drops(handle->md.device);
|
|
|
|
/*
|
|
* Current Linux kernels use the protocol family PF_PACKET to
|
|
* allow direct access to all packets on the network while
|
|
* older kernels had a special socket type SOCK_PACKET to
|
|
* implement this feature.
|
|
* While this old implementation is kind of obsolete we need
|
|
* to be compatible with older kernels for a while so we are
|
|
* trying both methods with the newer method preferred.
|
|
*/
|
|
|
|
if ((status = activate_new(handle)) == 1) {
|
|
/*
|
|
* Success.
|
|
* Try to use memory-mapped access.
|
|
*/
|
|
switch (activate_mmap(handle)) {
|
|
|
|
case 1:
|
|
/* we succeeded; nothing more to do */
|
|
return 0;
|
|
|
|
case 0:
|
|
/*
|
|
* Kernel doesn't support it - just continue
|
|
* with non-memory-mapped access.
|
|
*/
|
|
status = 0;
|
|
break;
|
|
|
|
case -1:
|
|
/*
|
|
* We failed to set up to use it, or kernel
|
|
* supports it, but we failed to enable it;
|
|
* return an error. handle->errbuf contains
|
|
* an error message.
|
|
*/
|
|
status = PCAP_ERROR;
|
|
goto fail;
|
|
}
|
|
}
|
|
else if (status == 0) {
|
|
/* Non-fatal error; try old way */
|
|
if ((status = activate_old(handle)) != 1) {
|
|
/*
|
|
* Both methods to open the packet socket failed.
|
|
* Tidy up and report our failure (handle->errbuf
|
|
* is expected to be set by the functions above).
|
|
*/
|
|
goto fail;
|
|
}
|
|
} else {
|
|
/*
|
|
* Fatal error with the new way; just fail.
|
|
* status has the error return; if it's PCAP_ERROR,
|
|
* handle->errbuf has been set appropriately.
|
|
*/
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* We set up the socket, but not with memory-mapped access.
|
|
*/
|
|
if (handle->opt.buffer_size != 0) {
|
|
/*
|
|
* Set the socket buffer size to the specified value.
|
|
*/
|
|
if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF,
|
|
&handle->opt.buffer_size,
|
|
sizeof(handle->opt.buffer_size)) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"SO_RCVBUF: %s", pcap_strerror(errno));
|
|
status = PCAP_ERROR;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
/* Allocate the buffer */
|
|
|
|
handle->buffer = malloc(handle->bufsize + handle->offset);
|
|
if (!handle->buffer) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"malloc: %s", pcap_strerror(errno));
|
|
status = PCAP_ERROR;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* "handle->fd" is a socket, so "select()" and "poll()"
|
|
* should work on it.
|
|
*/
|
|
handle->selectable_fd = handle->fd;
|
|
|
|
return status;
|
|
|
|
fail:
|
|
pcap_cleanup_linux(handle);
|
|
return status;
|
|
}
|
|
|
|
/*
|
|
* Read at most max_packets from the capture stream and call the callback
|
|
* for each of them. Returns the number of packets handled or -1 if an
|
|
* error occured.
|
|
*/
|
|
static int
|
|
pcap_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
|
|
{
|
|
/*
|
|
* Currently, on Linux only one packet is delivered per read,
|
|
* so we don't loop.
|
|
*/
|
|
return pcap_read_packet(handle, callback, user);
|
|
}
|
|
|
|
/*
|
|
* Read a packet from the socket calling the handler provided by
|
|
* the user. Returns the number of packets received or -1 if an
|
|
* error occured.
|
|
*/
|
|
static int
|
|
pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
|
|
{
|
|
u_char *bp;
|
|
int offset;
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
struct sockaddr_ll from;
|
|
struct sll_header *hdrp;
|
|
#else
|
|
struct sockaddr from;
|
|
#endif
|
|
#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
|
|
struct iovec iov;
|
|
struct msghdr msg;
|
|
struct cmsghdr *cmsg;
|
|
union {
|
|
struct cmsghdr cmsg;
|
|
char buf[CMSG_SPACE(sizeof(struct tpacket_auxdata))];
|
|
} cmsg_buf;
|
|
#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
|
|
socklen_t fromlen;
|
|
#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
|
|
int packet_len, caplen;
|
|
struct pcap_pkthdr pcap_header;
|
|
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
/*
|
|
* If this is a cooked device, leave extra room for a
|
|
* fake packet header.
|
|
*/
|
|
if (handle->md.cooked)
|
|
offset = SLL_HDR_LEN;
|
|
else
|
|
offset = 0;
|
|
#else
|
|
/*
|
|
* This system doesn't have PF_PACKET sockets, so it doesn't
|
|
* support cooked devices.
|
|
*/
|
|
offset = 0;
|
|
#endif
|
|
|
|
/*
|
|
* Receive a single packet from the kernel.
|
|
* We ignore EINTR, as that might just be due to a signal
|
|
* being delivered - if the signal should interrupt the
|
|
* loop, the signal handler should call pcap_breakloop()
|
|
* to set handle->break_loop (we ignore it on other
|
|
* platforms as well).
|
|
* We also ignore ENETDOWN, so that we can continue to
|
|
* capture traffic if the interface goes down and comes
|
|
* back up again; comments in the kernel indicate that
|
|
* we'll just block waiting for packets if we try to
|
|
* receive from a socket that delivered ENETDOWN, and,
|
|
* if we're using a memory-mapped buffer, we won't even
|
|
* get notified of "network down" events.
|
|
*/
|
|
bp = handle->buffer + handle->offset;
|
|
|
|
#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
|
|
msg.msg_name = &from;
|
|
msg.msg_namelen = sizeof(from);
|
|
msg.msg_iov = &iov;
|
|
msg.msg_iovlen = 1;
|
|
msg.msg_control = &cmsg_buf;
|
|
msg.msg_controllen = sizeof(cmsg_buf);
|
|
msg.msg_flags = 0;
|
|
|
|
iov.iov_len = handle->bufsize - offset;
|
|
iov.iov_base = bp + offset;
|
|
#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
|
|
|
|
do {
|
|
/*
|
|
* Has "pcap_breakloop()" been called?
|
|
*/
|
|
if (handle->break_loop) {
|
|
/*
|
|
* Yes - clear the flag that indicates that it has,
|
|
* and return PCAP_ERROR_BREAK as an indication that
|
|
* we were told to break out of the loop.
|
|
*/
|
|
handle->break_loop = 0;
|
|
return PCAP_ERROR_BREAK;
|
|
}
|
|
|
|
#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
|
|
packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC);
|
|
#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
|
|
fromlen = sizeof(from);
|
|
packet_len = recvfrom(
|
|
handle->fd, bp + offset,
|
|
handle->bufsize - offset, MSG_TRUNC,
|
|
(struct sockaddr *) &from, &fromlen);
|
|
#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
|
|
} while (packet_len == -1 && errno == EINTR);
|
|
|
|
/* Check if an error occured */
|
|
|
|
if (packet_len == -1) {
|
|
switch (errno) {
|
|
|
|
case EAGAIN:
|
|
return 0; /* no packet there */
|
|
|
|
case ENETDOWN:
|
|
/*
|
|
* The device on which we're capturing went away.
|
|
*
|
|
* XXX - we should really return
|
|
* PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch()
|
|
* etc. aren't defined to return that.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"The interface went down");
|
|
return PCAP_ERROR;
|
|
|
|
default:
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"recvfrom: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
if (!handle->md.sock_packet) {
|
|
/*
|
|
* Unfortunately, there is a window between socket() and
|
|
* bind() where the kernel may queue packets from any
|
|
* interface. If we're bound to a particular interface,
|
|
* discard packets not from that interface.
|
|
*
|
|
* (If socket filters are supported, we could do the
|
|
* same thing we do when changing the filter; however,
|
|
* that won't handle packet sockets without socket
|
|
* filter support, and it's a bit more complicated.
|
|
* It would save some instructions per packet, however.)
|
|
*/
|
|
if (handle->md.ifindex != -1 &&
|
|
from.sll_ifindex != handle->md.ifindex)
|
|
return 0;
|
|
|
|
/*
|
|
* Do checks based on packet direction.
|
|
* We can only do this if we're using PF_PACKET; the
|
|
* address returned for SOCK_PACKET is a "sockaddr_pkt"
|
|
* which lacks the relevant packet type information.
|
|
*/
|
|
if (from.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 (from.sll_ifindex == handle->md.lo_ifindex)
|
|
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;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
/*
|
|
* If this is a cooked device, fill in the fake packet header.
|
|
*/
|
|
if (handle->md.cooked) {
|
|
/*
|
|
* Add the length of the fake header to the length
|
|
* of packet data we read.
|
|
*/
|
|
packet_len += SLL_HDR_LEN;
|
|
|
|
hdrp = (struct sll_header *)bp;
|
|
hdrp->sll_pkttype = map_packet_type_to_sll_type(from.sll_pkttype);
|
|
hdrp->sll_hatype = htons(from.sll_hatype);
|
|
hdrp->sll_halen = htons(from.sll_halen);
|
|
memcpy(hdrp->sll_addr, from.sll_addr,
|
|
(from.sll_halen > SLL_ADDRLEN) ?
|
|
SLL_ADDRLEN :
|
|
from.sll_halen);
|
|
hdrp->sll_protocol = from.sll_protocol;
|
|
}
|
|
|
|
#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI)
|
|
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
|
|
struct tpacket_auxdata *aux;
|
|
unsigned int len;
|
|
struct vlan_tag *tag;
|
|
|
|
if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) ||
|
|
cmsg->cmsg_level != SOL_PACKET ||
|
|
cmsg->cmsg_type != PACKET_AUXDATA)
|
|
continue;
|
|
|
|
aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg);
|
|
if (aux->tp_vlan_tci == 0)
|
|
continue;
|
|
|
|
len = packet_len > iov.iov_len ? iov.iov_len : packet_len;
|
|
if (len < 2 * ETH_ALEN)
|
|
break;
|
|
|
|
bp -= VLAN_TAG_LEN;
|
|
memmove(bp, bp + VLAN_TAG_LEN, 2 * ETH_ALEN);
|
|
|
|
tag = (struct vlan_tag *)(bp + 2 * ETH_ALEN);
|
|
tag->vlan_tpid = htons(ETH_P_8021Q);
|
|
tag->vlan_tci = htons(aux->tp_vlan_tci);
|
|
|
|
packet_len += VLAN_TAG_LEN;
|
|
}
|
|
#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */
|
|
#endif /* HAVE_PF_PACKET_SOCKETS */
|
|
|
|
/*
|
|
* XXX: According to the kernel source we should get the real
|
|
* packet len if calling recvfrom with MSG_TRUNC set. It does
|
|
* not seem to work here :(, but it is supported by this code
|
|
* anyway.
|
|
* To be honest the code RELIES on that feature so this is really
|
|
* broken with 2.2.x kernels.
|
|
* I spend a day to figure out what's going on and I found out
|
|
* that the following is happening:
|
|
*
|
|
* The packet comes from a random interface and the packet_rcv
|
|
* hook is called with a clone of the packet. That code inserts
|
|
* the packet into the receive queue of the packet socket.
|
|
* If a filter is attached to that socket that filter is run
|
|
* first - and there lies the problem. The default filter always
|
|
* cuts the packet at the snaplen:
|
|
*
|
|
* # tcpdump -d
|
|
* (000) ret #68
|
|
*
|
|
* So the packet filter cuts down the packet. The recvfrom call
|
|
* says "hey, it's only 68 bytes, it fits into the buffer" with
|
|
* the result that we don't get the real packet length. This
|
|
* is valid at least until kernel 2.2.17pre6.
|
|
*
|
|
* We currently handle this by making a copy of the filter
|
|
* program, fixing all "ret" instructions with non-zero
|
|
* operands to have an operand of 65535 so that the filter
|
|
* doesn't truncate the packet, and supplying that modified
|
|
* filter to the kernel.
|
|
*/
|
|
|
|
caplen = packet_len;
|
|
if (caplen > handle->snapshot)
|
|
caplen = handle->snapshot;
|
|
|
|
/* Run the packet filter if not using kernel filter */
|
|
if (!handle->md.use_bpf && handle->fcode.bf_insns) {
|
|
if (bpf_filter(handle->fcode.bf_insns, bp,
|
|
packet_len, caplen) == 0)
|
|
{
|
|
/* rejected by filter */
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* Fill in our own header data */
|
|
|
|
if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGSTAMP: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
pcap_header.caplen = caplen;
|
|
pcap_header.len = packet_len;
|
|
|
|
/*
|
|
* Count the packet.
|
|
*
|
|
* Arguably, we should count them before we check the filter,
|
|
* as on many other platforms "ps_recv" counts packets
|
|
* handed to the filter rather than packets that passed
|
|
* the filter, but if filtering is done in the kernel, we
|
|
* can't get a count of packets that passed the filter,
|
|
* and that would mean the meaning of "ps_recv" wouldn't
|
|
* be the same on all Linux systems.
|
|
*
|
|
* XXX - it's not the same on all systems in any case;
|
|
* ideally, we should have a "get the statistics" call
|
|
* that supplies more counts and indicates which of them
|
|
* it supplies, so that we supply a count of packets
|
|
* handed to the filter only on platforms where that
|
|
* information is available.
|
|
*
|
|
* We count them here even if we can get the packet count
|
|
* from the kernel, as we can only determine at run time
|
|
* whether we'll be able to get it from the kernel (if
|
|
* HAVE_TPACKET_STATS isn't defined, we can't get it from
|
|
* the kernel, but if it is defined, the library might
|
|
* have been built with a 2.4 or later kernel, but we
|
|
* might be running on a 2.2[.x] kernel without Alexey
|
|
* Kuznetzov's turbopacket patches, and thus the kernel
|
|
* might not be able to supply those statistics). We
|
|
* could, I guess, try, when opening the socket, to get
|
|
* the statistics, and if we can not increment the count
|
|
* here, but it's not clear that always incrementing
|
|
* the count is more expensive than always testing a flag
|
|
* in memory.
|
|
*
|
|
* We keep the count in "md.packets_read", and use that for
|
|
* "ps_recv" if we can't get the statistics from the kernel.
|
|
* We do that because, if we *can* get the statistics from
|
|
* the kernel, we use "md.stat.ps_recv" and "md.stat.ps_drop"
|
|
* as running counts, as reading the statistics from the
|
|
* kernel resets the kernel statistics, and if we directly
|
|
* increment "md.stat.ps_recv" here, that means it will
|
|
* count packets *twice* on systems where we can get kernel
|
|
* statistics - once here, and once in pcap_stats_linux().
|
|
*/
|
|
handle->md.packets_read++;
|
|
|
|
/* Call the user supplied callback function */
|
|
callback(userdata, &pcap_header, bp);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
pcap_inject_linux(pcap_t *handle, const void *buf, size_t size)
|
|
{
|
|
int ret;
|
|
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
if (!handle->md.sock_packet) {
|
|
/* PF_PACKET socket */
|
|
if (handle->md.ifindex == -1) {
|
|
/*
|
|
* We don't support sending on the "any" device.
|
|
*/
|
|
strlcpy(handle->errbuf,
|
|
"Sending packets isn't supported on the \"any\" device",
|
|
PCAP_ERRBUF_SIZE);
|
|
return (-1);
|
|
}
|
|
|
|
if (handle->md.cooked) {
|
|
/*
|
|
* We don't support sending on the "any" device.
|
|
*
|
|
* XXX - how do you send on a bound cooked-mode
|
|
* socket?
|
|
* Is a "sendto()" required there?
|
|
*/
|
|
strlcpy(handle->errbuf,
|
|
"Sending packets isn't supported in cooked mode",
|
|
PCAP_ERRBUF_SIZE);
|
|
return (-1);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
ret = send(handle->fd, buf, size, 0);
|
|
if (ret == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
|
|
pcap_strerror(errno));
|
|
return (-1);
|
|
}
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Get the statistics for the given packet capture handle.
|
|
* Reports the number of dropped packets iff the kernel supports
|
|
* the PACKET_STATISTICS "getsockopt()" argument (2.4 and later
|
|
* kernels, and 2.2[.x] kernels with Alexey Kuznetzov's turbopacket
|
|
* patches); otherwise, that information isn't available, and we lie
|
|
* and report 0 as the count of dropped packets.
|
|
*/
|
|
static int
|
|
pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
|
|
{
|
|
#ifdef HAVE_TPACKET_STATS
|
|
struct tpacket_stats kstats;
|
|
socklen_t len = sizeof (struct tpacket_stats);
|
|
#endif
|
|
|
|
long if_dropped = 0;
|
|
|
|
/*
|
|
* To fill in ps_ifdrop, we parse /proc/net/dev for the number
|
|
*/
|
|
if (handle->opt.promisc)
|
|
{
|
|
if_dropped = handle->md.proc_dropped;
|
|
handle->md.proc_dropped = linux_if_drops(handle->md.device);
|
|
handle->md.stat.ps_ifdrop += (handle->md.proc_dropped - if_dropped);
|
|
}
|
|
|
|
#ifdef HAVE_TPACKET_STATS
|
|
/*
|
|
* Try to get the packet counts from the kernel.
|
|
*/
|
|
if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS,
|
|
&kstats, &len) > -1) {
|
|
/*
|
|
* On systems where the PACKET_STATISTICS "getsockopt()"
|
|
* argument is supported on PF_PACKET sockets:
|
|
*
|
|
* "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 the
|
|
* 2.4.9 kernel, "tp_packets" is incremented for every
|
|
* packet that passes the packet filter *and* is
|
|
* successfully queued on the socket; "tp_drops" is
|
|
* incremented for every packet dropped because there's
|
|
* not enough free space in the socket 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.
|
|
*/
|
|
handle->md.stat.ps_recv += kstats.tp_packets;
|
|
handle->md.stat.ps_drop += kstats.tp_drops;
|
|
*stats = handle->md.stat;
|
|
return 0;
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* If the error was EOPNOTSUPP, fall through, so that
|
|
* if you build the library on a system with
|
|
* "struct tpacket_stats" and run it on a system
|
|
* that doesn't, it works as it does if the library
|
|
* is built on a system without "struct tpacket_stats".
|
|
*/
|
|
if (errno != EOPNOTSUPP) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"pcap_stats: %s", pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
}
|
|
#endif
|
|
/*
|
|
* On systems where the PACKET_STATISTICS "getsockopt()" argument
|
|
* is not supported on PF_PACKET sockets:
|
|
*
|
|
* "ps_recv" counts only packets that *passed* the filter,
|
|
* not packets that didn't pass the filter. It does not
|
|
* count packets dropped because we ran out of buffer
|
|
* space.
|
|
*
|
|
* "ps_drop" is not supported.
|
|
*
|
|
* "ps_ifdrop" is supported. It will return the number
|
|
* of drops the interface reports in /proc/net/dev,
|
|
* if that is available.
|
|
*
|
|
* "ps_recv" doesn't include packets not yet read from
|
|
* the kernel by libpcap.
|
|
*
|
|
* We maintain the count of packets processed by libpcap in
|
|
* "md.packets_read", for reasons described in the comment
|
|
* at the end of pcap_read_packet(). We have no idea how many
|
|
* packets were dropped by the kernel buffers -- but we know
|
|
* how many the interface dropped, so we can return that.
|
|
*/
|
|
|
|
stats->ps_recv = handle->md.packets_read;
|
|
stats->ps_drop = 0;
|
|
stats->ps_ifdrop = handle->md.stat.ps_ifdrop;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Get from "/sys/class/net" all interfaces listed there; if they're
|
|
* already in the list of interfaces we have, that won't add another
|
|
* instance, but if they're not, that'll add them.
|
|
*
|
|
* We don't bother getting any addresses for them; it appears you can't
|
|
* use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
|
|
* although some other types of addresses can be fetched with SIOCGIFADDR,
|
|
* we don't bother with them for now.
|
|
*
|
|
* We also don't fail if we couldn't open "/sys/class/net"; we just leave
|
|
* the list of interfaces as is, and return 0, so that we can try
|
|
* scanning /proc/net/dev.
|
|
*/
|
|
static int
|
|
scan_sys_class_net(pcap_if_t **devlistp, char *errbuf)
|
|
{
|
|
DIR *sys_class_net_d;
|
|
int fd;
|
|
struct dirent *ent;
|
|
char *p;
|
|
char name[512]; /* XXX - pick a size */
|
|
char *q, *saveq;
|
|
struct ifreq ifrflags;
|
|
int ret = 1;
|
|
|
|
sys_class_net_d = opendir("/sys/class/net");
|
|
if (sys_class_net_d == NULL && errno == ENOENT)
|
|
return (0);
|
|
|
|
/*
|
|
* Create a socket from which to fetch interface information.
|
|
*/
|
|
fd = socket(AF_INET, SOCK_DGRAM, 0);
|
|
if (fd < 0) {
|
|
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
|
|
"socket: %s", pcap_strerror(errno));
|
|
return (-1);
|
|
}
|
|
|
|
for (;;) {
|
|
errno = 0;
|
|
ent = readdir(sys_class_net_d);
|
|
if (ent == NULL) {
|
|
/*
|
|
* Error or EOF; if errno != 0, it's an error.
|
|
*/
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Ignore directories (".", "..", and any subdirectories).
|
|
*/
|
|
if (ent->d_type == DT_DIR)
|
|
continue;
|
|
|
|
/*
|
|
* Get the interface name.
|
|
*/
|
|
p = &ent->d_name[0];
|
|
q = &name[0];
|
|
while (*p != '\0' && isascii(*p) && !isspace(*p)) {
|
|
if (*p == ':') {
|
|
/*
|
|
* This could be the separator between a
|
|
* name and an alias number, or it could be
|
|
* the separator between a name with no
|
|
* alias number and the next field.
|
|
*
|
|
* If there's a colon after digits, it
|
|
* separates the name and the alias number,
|
|
* otherwise it separates the name and the
|
|
* next field.
|
|
*/
|
|
saveq = q;
|
|
while (isascii(*p) && isdigit(*p))
|
|
*q++ = *p++;
|
|
if (*p != ':') {
|
|
/*
|
|
* That was the next field,
|
|
* not the alias number.
|
|
*/
|
|
q = saveq;
|
|
}
|
|
break;
|
|
} else
|
|
*q++ = *p++;
|
|
}
|
|
*q = '\0';
|
|
|
|
/*
|
|
* Get the flags for this interface, and skip it if
|
|
* it's not up.
|
|
*/
|
|
strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
|
|
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
|
|
if (errno == ENXIO)
|
|
continue;
|
|
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGIFFLAGS: %.*s: %s",
|
|
(int)sizeof(ifrflags.ifr_name),
|
|
ifrflags.ifr_name,
|
|
pcap_strerror(errno));
|
|
ret = -1;
|
|
break;
|
|
}
|
|
if (!(ifrflags.ifr_flags & IFF_UP))
|
|
continue;
|
|
|
|
/*
|
|
* Add an entry for this interface, with no addresses.
|
|
*/
|
|
if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
|
|
errbuf) == -1) {
|
|
/*
|
|
* Failure.
|
|
*/
|
|
ret = -1;
|
|
break;
|
|
}
|
|
}
|
|
if (ret != -1) {
|
|
/*
|
|
* Well, we didn't fail for any other reason; did we
|
|
* fail due to an error reading the directory?
|
|
*/
|
|
if (errno != 0) {
|
|
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
|
|
"Error reading /sys/class/net: %s",
|
|
pcap_strerror(errno));
|
|
ret = -1;
|
|
}
|
|
}
|
|
|
|
(void)close(fd);
|
|
(void)closedir(sys_class_net_d);
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Get from "/proc/net/dev" all interfaces listed there; if they're
|
|
* already in the list of interfaces we have, that won't add another
|
|
* instance, but if they're not, that'll add them.
|
|
*
|
|
* See comments from scan_sys_class_net().
|
|
*/
|
|
static int
|
|
scan_proc_net_dev(pcap_if_t **devlistp, char *errbuf)
|
|
{
|
|
FILE *proc_net_f;
|
|
int fd;
|
|
char linebuf[512];
|
|
int linenum;
|
|
char *p;
|
|
char name[512]; /* XXX - pick a size */
|
|
char *q, *saveq;
|
|
struct ifreq ifrflags;
|
|
int ret = 0;
|
|
|
|
proc_net_f = fopen("/proc/net/dev", "r");
|
|
if (proc_net_f == NULL && errno == ENOENT)
|
|
return (0);
|
|
|
|
/*
|
|
* Create a socket from which to fetch interface information.
|
|
*/
|
|
fd = socket(AF_INET, SOCK_DGRAM, 0);
|
|
if (fd < 0) {
|
|
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
|
|
"socket: %s", pcap_strerror(errno));
|
|
return (-1);
|
|
}
|
|
|
|
for (linenum = 1;
|
|
fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
|
|
/*
|
|
* Skip the first two lines - they're headers.
|
|
*/
|
|
if (linenum <= 2)
|
|
continue;
|
|
|
|
p = &linebuf[0];
|
|
|
|
/*
|
|
* Skip leading white space.
|
|
*/
|
|
while (*p != '\0' && isascii(*p) && isspace(*p))
|
|
p++;
|
|
if (*p == '\0' || *p == '\n')
|
|
continue; /* blank line */
|
|
|
|
/*
|
|
* Get the interface name.
|
|
*/
|
|
q = &name[0];
|
|
while (*p != '\0' && isascii(*p) && !isspace(*p)) {
|
|
if (*p == ':') {
|
|
/*
|
|
* This could be the separator between a
|
|
* name and an alias number, or it could be
|
|
* the separator between a name with no
|
|
* alias number and the next field.
|
|
*
|
|
* If there's a colon after digits, it
|
|
* separates the name and the alias number,
|
|
* otherwise it separates the name and the
|
|
* next field.
|
|
*/
|
|
saveq = q;
|
|
while (isascii(*p) && isdigit(*p))
|
|
*q++ = *p++;
|
|
if (*p != ':') {
|
|
/*
|
|
* That was the next field,
|
|
* not the alias number.
|
|
*/
|
|
q = saveq;
|
|
}
|
|
break;
|
|
} else
|
|
*q++ = *p++;
|
|
}
|
|
*q = '\0';
|
|
|
|
/*
|
|
* Get the flags for this interface, and skip it if
|
|
* it's not up.
|
|
*/
|
|
strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
|
|
if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
|
|
if (errno == ENXIO)
|
|
continue;
|
|
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGIFFLAGS: %.*s: %s",
|
|
(int)sizeof(ifrflags.ifr_name),
|
|
ifrflags.ifr_name,
|
|
pcap_strerror(errno));
|
|
ret = -1;
|
|
break;
|
|
}
|
|
if (!(ifrflags.ifr_flags & IFF_UP))
|
|
continue;
|
|
|
|
/*
|
|
* Add an entry for this interface, with no addresses.
|
|
*/
|
|
if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
|
|
errbuf) == -1) {
|
|
/*
|
|
* Failure.
|
|
*/
|
|
ret = -1;
|
|
break;
|
|
}
|
|
}
|
|
if (ret != -1) {
|
|
/*
|
|
* Well, we didn't fail for any other reason; did we
|
|
* fail due to an error reading the file?
|
|
*/
|
|
if (ferror(proc_net_f)) {
|
|
(void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
|
|
"Error reading /proc/net/dev: %s",
|
|
pcap_strerror(errno));
|
|
ret = -1;
|
|
}
|
|
}
|
|
|
|
(void)close(fd);
|
|
(void)fclose(proc_net_f);
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
* Description string for the "any" device.
|
|
*/
|
|
static const char any_descr[] = "Pseudo-device that captures on all interfaces";
|
|
|
|
int
|
|
pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
|
|
{
|
|
int ret;
|
|
|
|
/*
|
|
* Read "/sys/class/net", and add to the list of interfaces all
|
|
* interfaces listed there that we don't already have, because,
|
|
* on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses,
|
|
* and even getifaddrs() won't return information about
|
|
* interfaces with no addresses, so you need to read "/sys/class/net"
|
|
* to get the names of the rest of the interfaces.
|
|
*/
|
|
ret = scan_sys_class_net(alldevsp, errbuf);
|
|
if (ret == -1)
|
|
return (-1); /* failed */
|
|
if (ret == 0) {
|
|
/*
|
|
* No /sys/class/net; try reading /proc/net/dev instead.
|
|
*/
|
|
if (scan_proc_net_dev(alldevsp, errbuf) == -1)
|
|
return (-1);
|
|
}
|
|
|
|
/*
|
|
* Add the "any" device.
|
|
*/
|
|
if (pcap_add_if(alldevsp, "any", 0, any_descr, errbuf) < 0)
|
|
return (-1);
|
|
|
|
#ifdef HAVE_DAG_API
|
|
/*
|
|
* Add DAG devices.
|
|
*/
|
|
if (dag_platform_finddevs(alldevsp, errbuf) < 0)
|
|
return (-1);
|
|
#endif /* HAVE_DAG_API */
|
|
|
|
#ifdef HAVE_SEPTEL_API
|
|
/*
|
|
* Add Septel devices.
|
|
*/
|
|
if (septel_platform_finddevs(alldevsp, errbuf) < 0)
|
|
return (-1);
|
|
#endif /* HAVE_SEPTEL_API */
|
|
|
|
#ifdef HAVE_SNF_API
|
|
if (snf_platform_finddevs(alldevsp, errbuf) < 0)
|
|
return (-1);
|
|
#endif /* HAVE_SNF_API */
|
|
|
|
#ifdef PCAP_SUPPORT_BT
|
|
/*
|
|
* Add Bluetooth devices.
|
|
*/
|
|
if (bt_platform_finddevs(alldevsp, errbuf) < 0)
|
|
return (-1);
|
|
#endif
|
|
|
|
#ifdef PCAP_SUPPORT_USB
|
|
/*
|
|
* Add USB devices.
|
|
*/
|
|
if (usb_platform_finddevs(alldevsp, errbuf) < 0)
|
|
return (-1);
|
|
#endif
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Attach the given BPF code to the packet capture device.
|
|
*/
|
|
static int
|
|
pcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter,
|
|
int is_mmapped)
|
|
{
|
|
#ifdef SO_ATTACH_FILTER
|
|
struct sock_fprog fcode;
|
|
int can_filter_in_kernel;
|
|
int err = 0;
|
|
#endif
|
|
|
|
if (!handle)
|
|
return -1;
|
|
if (!filter) {
|
|
strncpy(handle->errbuf, "setfilter: No filter specified",
|
|
PCAP_ERRBUF_SIZE);
|
|
return -1;
|
|
}
|
|
|
|
/* 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 overriden if
|
|
* installing a kernel filter succeeds.
|
|
*/
|
|
handle->md.use_bpf = 0;
|
|
|
|
/* Install kernel level filter if possible */
|
|
|
|
#ifdef SO_ATTACH_FILTER
|
|
#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 65535 as the
|
|
* operand if we're not capturing in memory-mapped modee,
|
|
* 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, is_mmapped)) {
|
|
|
|
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;
|
|
}
|
|
}
|
|
|
|
if (can_filter_in_kernel) {
|
|
if ((err = set_kernel_filter(handle, &fcode)) == 0)
|
|
{
|
|
/* Installation succeded - using kernel filter. */
|
|
handle->md.use_bpf = 1;
|
|
}
|
|
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 != 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 (!handle->md.use_bpf)
|
|
reset_kernel_filter(handle);
|
|
|
|
/*
|
|
* 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;
|
|
#endif /* SO_ATTACH_FILTER */
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter)
|
|
{
|
|
return pcap_setfilter_linux_common(handle, filter, 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)
|
|
{
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
if (!handle->md.sock_packet) {
|
|
handle->direction = d;
|
|
return 0;
|
|
}
|
|
#endif
|
|
/*
|
|
* We're not using PF_PACKET sockets, so we can't determine
|
|
* the direction of the packet.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"Setting direction is not supported on SOCK_PACKET sockets");
|
|
return -1;
|
|
}
|
|
|
|
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
/*
|
|
* Map the PACKET_ value to a LINUX_SLL_ value; we
|
|
* want the same numerical value to be used in
|
|
* the link-layer header even if the numerical values
|
|
* for the PACKET_ #defines change, so that programs
|
|
* that look at the packet type field will always be
|
|
* able to handle DLT_LINUX_SLL captures.
|
|
*/
|
|
static short int
|
|
map_packet_type_to_sll_type(short int sll_pkttype)
|
|
{
|
|
switch (sll_pkttype) {
|
|
|
|
case PACKET_HOST:
|
|
return htons(LINUX_SLL_HOST);
|
|
|
|
case PACKET_BROADCAST:
|
|
return htons(LINUX_SLL_BROADCAST);
|
|
|
|
case PACKET_MULTICAST:
|
|
return htons(LINUX_SLL_MULTICAST);
|
|
|
|
case PACKET_OTHERHOST:
|
|
return htons(LINUX_SLL_OTHERHOST);
|
|
|
|
case PACKET_OUTGOING:
|
|
return htons(LINUX_SLL_OUTGOING);
|
|
|
|
default:
|
|
return -1;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* 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, int cooked_ok)
|
|
{
|
|
switch (arptype) {
|
|
|
|
case ARPHRD_ETHER:
|
|
/*
|
|
* This is (presumably) a real Ethernet capture; 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 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 "activate_new()",
|
|
* as we fall back on cooked mode there; are there any
|
|
* others?
|
|
*/
|
|
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;
|
|
|
|
#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:
|
|
/*
|
|
* We assume that those all mean RFC 2625 IP-over-
|
|
* Fibre Channel, with the RFC 2625 header at
|
|
* the beginning of the packet.
|
|
*/
|
|
handle->linktype = DLT_IP_OVER_FC;
|
|
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 */
|
|
//handle->md.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;
|
|
|
|
default:
|
|
handle->linktype = -1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* ===== Functions to interface to the newer kernels ================== */
|
|
|
|
/*
|
|
* Try to open a packet socket using the new kernel PF_PACKET interface.
|
|
* Returns 1 on success, 0 on an error that means the new interface isn't
|
|
* present (so the old SOCK_PACKET interface should be tried), and a
|
|
* PCAP_ERROR_ value on an error that means that the old mechanism won't
|
|
* work either (so it shouldn't be tried).
|
|
*/
|
|
static int
|
|
activate_new(pcap_t *handle)
|
|
{
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
const char *device = handle->opt.source;
|
|
int is_any_device = (strcmp(device, "any") == 0);
|
|
int sock_fd = -1, arptype;
|
|
#ifdef HAVE_PACKET_AUXDATA
|
|
int val;
|
|
#endif
|
|
int err = 0;
|
|
struct packet_mreq mr;
|
|
|
|
/*
|
|
* Open a socket with protocol family packet. If the
|
|
* "any" device was specified, we open a SOCK_DGRAM
|
|
* socket for the cooked interface, otherwise we first
|
|
* try a SOCK_RAW socket for the raw interface.
|
|
*/
|
|
sock_fd = is_any_device ?
|
|
socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL)) :
|
|
socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
|
|
|
|
if (sock_fd == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
|
|
pcap_strerror(errno) );
|
|
return 0; /* try old mechanism */
|
|
}
|
|
|
|
/* It seems the kernel supports the new interface. */
|
|
handle->md.sock_packet = 0;
|
|
|
|
/*
|
|
* Get the interface index of the loopback device.
|
|
* If the attempt fails, don't fail, just set the
|
|
* "md.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()".
|
|
*/
|
|
handle->md.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. */
|
|
handle->md.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 (handle->md.mondevice != NULL)
|
|
device = handle->md.mondevice;
|
|
}
|
|
arptype = iface_get_arptype(sock_fd, device, handle->errbuf);
|
|
if (arptype < 0) {
|
|
close(sock_fd);
|
|
return arptype;
|
|
}
|
|
map_arphrd_to_dlt(handle, arptype, 1);
|
|
if (handle->linktype == -1 ||
|
|
handle->linktype == DLT_LINUX_SLL ||
|
|
handle->linktype == DLT_LINUX_IRDA ||
|
|
handle->linktype == DLT_LINUX_LAPD ||
|
|
(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 (close(sock_fd) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"close: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
sock_fd = socket(PF_PACKET, SOCK_DGRAM,
|
|
htons(ETH_P_ALL));
|
|
if (sock_fd == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"socket: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
handle->md.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;
|
|
}
|
|
|
|
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_LINUX_SLL;
|
|
}
|
|
|
|
handle->md.ifindex = iface_get_id(sock_fd, device,
|
|
handle->errbuf);
|
|
if (handle->md.ifindex == -1) {
|
|
close(sock_fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
if ((err = iface_bind(sock_fd, handle->md.ifindex,
|
|
handle->errbuf)) != 1) {
|
|
close(sock_fd);
|
|
if (err < 0)
|
|
return err;
|
|
else
|
|
return 0; /* try old mechanism */
|
|
}
|
|
} else {
|
|
/*
|
|
* The "any" device.
|
|
*/
|
|
if (handle->opt.rfmon) {
|
|
/*
|
|
* It doesn't support monitor mode.
|
|
*/
|
|
return PCAP_ERROR_RFMON_NOTSUP;
|
|
}
|
|
|
|
/*
|
|
* It uses cooked mode.
|
|
*/
|
|
handle->md.cooked = 1;
|
|
handle->linktype = DLT_LINUX_SLL;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
handle->md.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 = handle->md.ifindex;
|
|
mr.mr_type = PACKET_MR_PROMISC;
|
|
if (setsockopt(sock_fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP,
|
|
&mr, sizeof(mr)) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"setsockopt: %s", pcap_strerror(errno));
|
|
close(sock_fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
|
|
/* Enable auxillary data if supported and reserve room for
|
|
* reconstructing VLAN headers. */
|
|
#ifdef HAVE_PACKET_AUXDATA
|
|
val = 1;
|
|
if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val,
|
|
sizeof(val)) == -1 && errno != ENOPROTOOPT) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"setsockopt: %s", pcap_strerror(errno));
|
|
close(sock_fd);
|
|
return PCAP_ERROR;
|
|
}
|
|
handle->offset += VLAN_TAG_LEN;
|
|
#endif /* HAVE_PACKET_AUXDATA */
|
|
|
|
/*
|
|
* This is a 2.2[.x] or later kernel (we know that
|
|
* because we're not using a SOCK_PACKET socket -
|
|
* PF_PACKET is supported only in 2.2 and later
|
|
* kernels).
|
|
*
|
|
* We can safely pass "recvfrom()" a byte count
|
|
* based on the snapshot length.
|
|
*
|
|
* 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()").
|
|
*/
|
|
if (handle->md.cooked) {
|
|
if (handle->snapshot < SLL_HDR_LEN + 1)
|
|
handle->snapshot = SLL_HDR_LEN + 1;
|
|
}
|
|
handle->bufsize = handle->snapshot;
|
|
|
|
/* Save the socket FD in the pcap structure */
|
|
handle->fd = sock_fd;
|
|
|
|
return 1;
|
|
#else
|
|
strncpy(ebuf,
|
|
"New packet capturing interface not supported by build "
|
|
"environment", PCAP_ERRBUF_SIZE);
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
static int
|
|
activate_mmap(pcap_t *handle)
|
|
{
|
|
#ifdef HAVE_PACKET_RING
|
|
int ret;
|
|
|
|
/*
|
|
* Attempt to allocate a buffer to hold the contents of one
|
|
* packet, for use by the oneshot callback.
|
|
*/
|
|
handle->md.oneshot_buffer = malloc(handle->snapshot);
|
|
if (handle->md.oneshot_buffer == NULL) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't allocate oneshot buffer: %s",
|
|
pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
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(handle->md.oneshot_buffer);
|
|
return ret;
|
|
}
|
|
ret = create_ring(handle);
|
|
if (ret != 1) {
|
|
free(handle->md.oneshot_buffer);
|
|
return ret;
|
|
}
|
|
|
|
/* override some defaults and inherit the other fields from
|
|
* activate_new
|
|
* handle->offset is used to get the current position into the rx ring
|
|
* handle->cc is used to store the ring size */
|
|
handle->read_op = pcap_read_linux_mmap;
|
|
handle->cleanup_op = pcap_cleanup_linux_mmap;
|
|
handle->setfilter_op = pcap_setfilter_linux_mmap;
|
|
handle->setnonblock_op = pcap_setnonblock_mmap;
|
|
handle->getnonblock_op = pcap_getnonblock_mmap;
|
|
handle->oneshot_callback = pcap_oneshot_mmap;
|
|
handle->selectable_fd = handle->fd;
|
|
return 1;
|
|
#else /* HAVE_PACKET_RING */
|
|
return 0;
|
|
#endif /* HAVE_PACKET_RING */
|
|
}
|
|
|
|
#ifdef HAVE_PACKET_RING
|
|
static int
|
|
prepare_tpacket_socket(pcap_t *handle)
|
|
{
|
|
#ifdef HAVE_TPACKET2
|
|
socklen_t len;
|
|
int val;
|
|
#endif
|
|
|
|
handle->md.tp_version = TPACKET_V1;
|
|
handle->md.tp_hdrlen = sizeof(struct tpacket_hdr);
|
|
|
|
#ifdef HAVE_TPACKET2
|
|
/* Probe whether kernel supports TPACKET_V2 */
|
|
val = TPACKET_V2;
|
|
len = sizeof(val);
|
|
if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) {
|
|
if (errno == ENOPROTOOPT)
|
|
return 1; /* no - just drive on */
|
|
|
|
/* Yes - treat as a failure. */
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't get TPACKET_V2 header len on packet socket: %s",
|
|
pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
handle->md.tp_hdrlen = val;
|
|
|
|
val = TPACKET_V2;
|
|
if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val,
|
|
sizeof(val)) < 0) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't activate TPACKET_V2 on packet socket: %s",
|
|
pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
handle->md.tp_version = TPACKET_V2;
|
|
|
|
/* Reserve space for VLAN tag reconstruction */
|
|
val = VLAN_TAG_LEN;
|
|
if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &val,
|
|
sizeof(val)) < 0) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't set up reserve on packet socket: %s",
|
|
pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
#endif /* HAVE_TPACKET2 */
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
create_ring(pcap_t *handle)
|
|
{
|
|
unsigned i, j, frames_per_block;
|
|
struct tpacket_req req;
|
|
|
|
/* Note that with large snapshot (say 64K) only a few frames
|
|
* will be available in the ring even with pretty large ring size
|
|
* (and a lot of memory will be unused).
|
|
* The snap len should be carefully chosen to achive best
|
|
* performance */
|
|
req.tp_frame_size = TPACKET_ALIGN(handle->snapshot +
|
|
TPACKET_ALIGN(handle->md.tp_hdrlen) +
|
|
sizeof(struct sockaddr_ll));
|
|
req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size;
|
|
|
|
/* compute the minumum 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;
|
|
|
|
/* 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;
|
|
|
|
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;
|
|
}
|
|
if (errno == ENOPROTOOPT) {
|
|
/*
|
|
* We don't have ring buffer support in this kernel.
|
|
*/
|
|
return 0;
|
|
}
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't create rx ring on packet socket: %s",
|
|
pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
/* memory map the rx ring */
|
|
handle->md.mmapbuflen = req.tp_block_nr * req.tp_block_size;
|
|
handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen,
|
|
PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0);
|
|
if (handle->md.mmapbuf == MAP_FAILED) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't mmap rx ring: %s", pcap_strerror(errno));
|
|
|
|
/* clear the allocated ring on error*/
|
|
destroy_ring(handle);
|
|
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) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't allocate ring of frame headers: %s",
|
|
pcap_strerror(errno));
|
|
|
|
destroy_ring(handle);
|
|
return -1;
|
|
}
|
|
|
|
/* fill the header ring with proper frame ptr*/
|
|
handle->offset = 0;
|
|
for (i=0; i<req.tp_block_nr; ++i) {
|
|
void *base = &handle->md.mmapbuf[i*req.tp_block_size];
|
|
for (j=0; j<frames_per_block; ++j, ++handle->offset) {
|
|
RING_GET_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)
|
|
{
|
|
/* tell the kernel to destroy the ring*/
|
|
struct tpacket_req req;
|
|
memset(&req, 0, sizeof(req));
|
|
setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING,
|
|
(void *) &req, sizeof(req));
|
|
|
|
/* if ring is mapped, unmap it*/
|
|
if (handle->md.mmapbuf) {
|
|
/* do not test for mmap failure, as we can't recover from any error */
|
|
munmap(handle->md.mmapbuf, handle->md.mmapbuflen);
|
|
handle->md.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_mmap(u_char *user, const struct pcap_pkthdr *h,
|
|
const u_char *bytes)
|
|
{
|
|
struct oneshot_userdata *sp = (struct oneshot_userdata *)user;
|
|
|
|
*sp->hdr = *h;
|
|
memcpy(sp->pd->md.oneshot_buffer, bytes, h->caplen);
|
|
*sp->pkt = sp->pd->md.oneshot_buffer;
|
|
}
|
|
|
|
static void
|
|
pcap_cleanup_linux_mmap( pcap_t *handle )
|
|
{
|
|
destroy_ring(handle);
|
|
if (handle->md.oneshot_buffer != NULL) {
|
|
free(handle->md.oneshot_buffer);
|
|
handle->md.oneshot_buffer = NULL;
|
|
}
|
|
pcap_cleanup_linux(handle);
|
|
}
|
|
|
|
|
|
static int
|
|
pcap_getnonblock_mmap(pcap_t *p, char *errbuf)
|
|
{
|
|
/* use negative value of timeout to indicate non blocking ops */
|
|
return (p->md.timeout<0);
|
|
}
|
|
|
|
static int
|
|
pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf)
|
|
{
|
|
/* map each value to the corresponding 2's complement, to
|
|
* preserve the timeout value provided with pcap_set_timeout */
|
|
if (nonblock) {
|
|
if (p->md.timeout >= 0) {
|
|
/*
|
|
* Timeout is non-negative, so we're not already
|
|
* in non-blocking mode; set it to the 2's
|
|
* complement, to make it negative, as an
|
|
* indication that we're in non-blocking mode.
|
|
*/
|
|
p->md.timeout = p->md.timeout*-1 - 1;
|
|
}
|
|
} else {
|
|
if (p->md.timeout < 0) {
|
|
/*
|
|
* Timeout is negative, so we're not already
|
|
* in blocking mode; reverse the previous
|
|
* operation, to make the timeout non-negative
|
|
* again.
|
|
*/
|
|
p->md.timeout = (p->md.timeout+1)*-1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static inline union thdr *
|
|
pcap_get_ring_frame(pcap_t *handle, int status)
|
|
{
|
|
union thdr h;
|
|
|
|
h.raw = RING_GET_FRAME(handle);
|
|
switch (handle->md.tp_version) {
|
|
case TPACKET_V1:
|
|
if (status != (h.h1->tp_status ? TP_STATUS_USER :
|
|
TP_STATUS_KERNEL))
|
|
return NULL;
|
|
break;
|
|
#ifdef HAVE_TPACKET2
|
|
case TPACKET_V2:
|
|
if (status != (h.h2->tp_status ? TP_STATUS_USER :
|
|
TP_STATUS_KERNEL))
|
|
return NULL;
|
|
break;
|
|
#endif
|
|
}
|
|
return h.raw;
|
|
}
|
|
|
|
#ifndef POLLRDHUP
|
|
#define POLLRDHUP 0
|
|
#endif
|
|
|
|
static int
|
|
pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback,
|
|
u_char *user)
|
|
{
|
|
int timeout;
|
|
int pkts = 0;
|
|
char c;
|
|
|
|
/* wait for frames availability.*/
|
|
if (!pcap_get_ring_frame(handle, TP_STATUS_USER)) {
|
|
struct pollfd pollinfo;
|
|
int ret;
|
|
|
|
pollinfo.fd = handle->fd;
|
|
pollinfo.events = POLLIN;
|
|
|
|
if (handle->md.timeout == 0)
|
|
timeout = -1; /* block forever */
|
|
else if (handle->md.timeout > 0)
|
|
timeout = handle->md.timeout; /* block for that amount of time */
|
|
else
|
|
timeout = 0; /* non-blocking mode - poll to pick up errors */
|
|
do {
|
|
ret = poll(&pollinfo, 1, timeout);
|
|
if (ret < 0 && errno != EINTR) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"can't poll on packet socket: %s",
|
|
pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
} else if (ret > 0 &&
|
|
(pollinfo.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) {
|
|
/*
|
|
* There's some indication other than
|
|
* "you can read on this descriptor" on
|
|
* the descriptor.
|
|
*/
|
|
if (pollinfo.revents & (POLLHUP | POLLRDHUP)) {
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"Hangup on packet socket");
|
|
return PCAP_ERROR;
|
|
}
|
|
if (pollinfo.revents & POLLERR) {
|
|
/*
|
|
* A recv() will give us the
|
|
* actual error code.
|
|
*
|
|
* XXX - make the socket non-blocking?
|
|
*/
|
|
if (recv(handle->fd, &c, sizeof c,
|
|
MSG_PEEK) != -1)
|
|
continue; /* what, no error? */
|
|
if (errno == ENETDOWN) {
|
|
/*
|
|
* The device on which we're
|
|
* capturing went away.
|
|
*
|
|
* XXX - we should really return
|
|
* PCAP_ERROR_IFACE_NOT_UP,
|
|
* but pcap_dispatch() etc.
|
|
* aren't defined to return
|
|
* that.
|
|
*/
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"The interface went down");
|
|
} else {
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"Error condition on packet socket: %s",
|
|
strerror(errno));
|
|
}
|
|
return PCAP_ERROR;
|
|
}
|
|
if (pollinfo.revents & POLLNVAL) {
|
|
snprintf(handle->errbuf,
|
|
PCAP_ERRBUF_SIZE,
|
|
"Invalid polling request on packet socket");
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
/* check for break loop condition on interrupted syscall*/
|
|
if (handle->break_loop) {
|
|
handle->break_loop = 0;
|
|
return PCAP_ERROR_BREAK;
|
|
}
|
|
} while (ret < 0);
|
|
}
|
|
|
|
/* non-positive values of max_packets are used to require all
|
|
* packets currently available in the ring */
|
|
while ((pkts < max_packets) || (max_packets <= 0)) {
|
|
int run_bpf;
|
|
struct sockaddr_ll *sll;
|
|
struct pcap_pkthdr pcaphdr;
|
|
unsigned char *bp;
|
|
union thdr h;
|
|
unsigned int tp_len;
|
|
unsigned int tp_mac;
|
|
unsigned int tp_snaplen;
|
|
unsigned int tp_sec;
|
|
unsigned int tp_usec;
|
|
|
|
h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
|
|
if (!h.raw)
|
|
break;
|
|
|
|
switch (handle->md.tp_version) {
|
|
case TPACKET_V1:
|
|
tp_len = h.h1->tp_len;
|
|
tp_mac = h.h1->tp_mac;
|
|
tp_snaplen = h.h1->tp_snaplen;
|
|
tp_sec = h.h1->tp_sec;
|
|
tp_usec = h.h1->tp_usec;
|
|
break;
|
|
#ifdef HAVE_TPACKET2
|
|
case TPACKET_V2:
|
|
tp_len = h.h2->tp_len;
|
|
tp_mac = h.h2->tp_mac;
|
|
tp_snaplen = h.h2->tp_snaplen;
|
|
tp_sec = h.h2->tp_sec;
|
|
tp_usec = h.h2->tp_nsec / 1000;
|
|
break;
|
|
#endif
|
|
default:
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"unsupported tpacket version %d",
|
|
handle->md.tp_version);
|
|
return -1;
|
|
}
|
|
/* perform sanity check on internal offset. */
|
|
if (tp_mac + tp_snaplen > handle->bufsize) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"corrupted frame on kernel ring mac "
|
|
"offset %d + caplen %d > 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 such case md.use_bpf 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 = (unsigned char*)h.raw + tp_mac;
|
|
run_bpf = (!handle->md.use_bpf) ||
|
|
((handle->md.use_bpf>1) && handle->md.use_bpf--);
|
|
if (run_bpf && handle->fcode.bf_insns &&
|
|
(bpf_filter(handle->fcode.bf_insns, bp,
|
|
tp_len, tp_snaplen) == 0))
|
|
goto skip;
|
|
|
|
/*
|
|
* Do checks based on packet direction.
|
|
*/
|
|
sll = (void *)h.raw + TPACKET_ALIGN(handle->md.tp_hdrlen);
|
|
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 == handle->md.lo_ifindex)
|
|
goto skip;
|
|
|
|
/*
|
|
* If the user only wants incoming packets, reject it.
|
|
*/
|
|
if (handle->direction == PCAP_D_IN)
|
|
goto skip;
|
|
} else {
|
|
/*
|
|
* Incoming packet.
|
|
* If the user only wants outgoing packets, reject it.
|
|
*/
|
|
if (handle->direction == PCAP_D_OUT)
|
|
goto skip;
|
|
}
|
|
|
|
/* 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 (handle->md.cooked) {
|
|
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 *)h.raw +
|
|
TPACKET_ALIGN(handle->md.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 = map_packet_type_to_sll_type(
|
|
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;
|
|
|
|
/* update packet len */
|
|
pcaphdr.caplen += SLL_HDR_LEN;
|
|
pcaphdr.len += SLL_HDR_LEN;
|
|
}
|
|
|
|
#ifdef HAVE_TPACKET2
|
|
if (handle->md.tp_version == TPACKET_V2 && h.h2->tp_vlan_tci &&
|
|
tp_snaplen >= 2 * ETH_ALEN) {
|
|
struct vlan_tag *tag;
|
|
|
|
bp -= VLAN_TAG_LEN;
|
|
memmove(bp, bp + VLAN_TAG_LEN, 2 * ETH_ALEN);
|
|
|
|
tag = (struct vlan_tag *)(bp + 2 * ETH_ALEN);
|
|
tag->vlan_tpid = htons(ETH_P_8021Q);
|
|
tag->vlan_tci = htons(h.h2->tp_vlan_tci);
|
|
|
|
pcaphdr.caplen += VLAN_TAG_LEN;
|
|
pcaphdr.len += VLAN_TAG_LEN;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
if (pcaphdr.caplen > handle->snapshot)
|
|
pcaphdr.caplen = handle->snapshot;
|
|
|
|
/* pass the packet to the user */
|
|
pkts++;
|
|
callback(user, &pcaphdr, bp);
|
|
handle->md.packets_read++;
|
|
|
|
skip:
|
|
/* next packet */
|
|
switch (handle->md.tp_version) {
|
|
case TPACKET_V1:
|
|
h.h1->tp_status = TP_STATUS_KERNEL;
|
|
break;
|
|
#ifdef HAVE_TPACKET2
|
|
case TPACKET_V2:
|
|
h.h2->tp_status = TP_STATUS_KERNEL;
|
|
break;
|
|
#endif
|
|
}
|
|
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;
|
|
}
|
|
|
|
static int
|
|
pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter)
|
|
{
|
|
int n, offset;
|
|
int ret;
|
|
|
|
/*
|
|
* Don't rewrite "ret" instructions; we don't need to, as
|
|
* we're not reading packets with recvmsg(), and we don't
|
|
* want to, as, by not rewriting them, the kernel can avoid
|
|
* copying extra data.
|
|
*/
|
|
ret = pcap_setfilter_linux_common(handle, filter, 1);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* if the kernel filter is enabled, we need to apply the filter on
|
|
* all packets present into the ring. Get an upper bound of their number
|
|
*/
|
|
if (!handle->md.use_bpf)
|
|
return ret;
|
|
|
|
/* walk the ring backward and count the free slot */
|
|
offset = handle->offset;
|
|
if (--handle->offset < 0)
|
|
handle->offset = handle->cc - 1;
|
|
for (n=0; n < handle->cc; ++n) {
|
|
if (--handle->offset < 0)
|
|
handle->offset = handle->cc - 1;
|
|
if (!pcap_get_ring_frame(handle, TP_STATUS_KERNEL))
|
|
break;
|
|
}
|
|
|
|
/* be careful to not change current ring position */
|
|
handle->offset = offset;
|
|
|
|
/* store the number of packets currently present in the ring */
|
|
handle->md.use_bpf = 1 + (handle->cc - n);
|
|
return ret;
|
|
}
|
|
|
|
#endif /* HAVE_PACKET_RING */
|
|
|
|
|
|
#ifdef HAVE_PF_PACKET_SOCKETS
|
|
/*
|
|
* 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));
|
|
strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
|
|
if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGIFINDEX: %s", pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
return ifr.ifr_ifindex;
|
|
}
|
|
|
|
/*
|
|
* Bind the socket associated with FD to the given device.
|
|
* Return 1 on success, 0 if we should try a SOCK_PACKET socket,
|
|
* or a PCAP_ERROR_ value on a hard error.
|
|
*/
|
|
static int
|
|
iface_bind(int fd, int ifindex, char *ebuf)
|
|
{
|
|
struct sockaddr_ll sll;
|
|
int err;
|
|
socklen_t errlen = sizeof(err);
|
|
|
|
memset(&sll, 0, sizeof(sll));
|
|
sll.sll_family = AF_PACKET;
|
|
sll.sll_ifindex = ifindex;
|
|
sll.sll_protocol = htons(ETH_P_ALL);
|
|
|
|
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;
|
|
} else {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"bind: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
}
|
|
|
|
/* Any pending errors, e.g., network is down? */
|
|
|
|
if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"getsockopt: %s", pcap_strerror(errno));
|
|
return 0;
|
|
}
|
|
|
|
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) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"bind: %s", pcap_strerror(err));
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
#ifdef IW_MODE_MONITOR
|
|
/*
|
|
* Check whether the device supports the Wireless Extensions.
|
|
* Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE
|
|
* if the device doesn't even exist.
|
|
*/
|
|
static int
|
|
has_wext(int sock_fd, const char *device, char *ebuf)
|
|
{
|
|
struct iwreq ireq;
|
|
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0)
|
|
return 1; /* yes */
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno));
|
|
if (errno == ENODEV)
|
|
return PCAP_ERROR_NO_SUCH_DEVICE;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Per me si va ne la citta dolente,
|
|
* Per me si va ne l'etterno dolore,
|
|
* ...
|
|
* Lasciate ogne speranza, voi ch'intrate.
|
|
*
|
|
* XXX - airmon-ng does special stuff with the Orinoco driver and the
|
|
* wlan-ng driver.
|
|
*/
|
|
typedef enum {
|
|
MONITOR_WEXT,
|
|
MONITOR_HOSTAP,
|
|
MONITOR_PRISM,
|
|
MONITOR_PRISM54,
|
|
MONITOR_ACX100,
|
|
MONITOR_RT2500,
|
|
MONITOR_RT2570,
|
|
MONITOR_RT73,
|
|
MONITOR_RTL8XXX
|
|
} monitor_type;
|
|
|
|
/*
|
|
* Use the Wireless Extensions, if we have them, to try to turn monitor mode
|
|
* on if it's not already on.
|
|
*
|
|
* Returns 1 on success, 0 if we don't support the Wireless Extensions
|
|
* on this device, or a PCAP_ERROR_ value if we do support them but
|
|
* we weren't able to turn monitor mode on.
|
|
*/
|
|
static int
|
|
enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device)
|
|
{
|
|
/*
|
|
* XXX - at least some adapters require non-Wireless Extensions
|
|
* mechanisms to turn monitor mode on.
|
|
*
|
|
* Atheros cards might require that a separate "monitor virtual access
|
|
* point" be created, with later versions of the madwifi driver.
|
|
* airmon-ng does "wlanconfig ath create wlandev {if} wlanmode
|
|
* monitor -bssid", which apparently spits out a line "athN"
|
|
* where "athN" is the monitor mode device. To leave monitor
|
|
* mode, it destroys the monitor mode device.
|
|
*
|
|
* Some Intel Centrino adapters might require private ioctls to get
|
|
* radio headers; the ipw2200 and ipw3945 drivers allow you to
|
|
* configure a separate "rtapN" interface to capture in monitor
|
|
* mode without preventing the adapter from operating normally.
|
|
* (airmon-ng doesn't appear to use that, though.)
|
|
*
|
|
* It would be Truly Wonderful if mac80211 and nl80211 cleaned this
|
|
* up, and if all drivers were converted to mac80211 drivers.
|
|
*
|
|
* If interface {if} is a mac80211 driver, the file
|
|
* /sys/class/net/{if}/phy80211 is a symlink to
|
|
* /sys/class/ieee80211/{phydev}, for some {phydev}.
|
|
*
|
|
* On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at
|
|
* least, has a "wmaster0" device and a "wlan0" device; the
|
|
* latter is the one with the IP address. Both show up in
|
|
* "tcpdump -D" output. Capturing on the wmaster0 device
|
|
* captures with 802.11 headers.
|
|
*
|
|
* airmon-ng searches through /sys/class/net for devices named
|
|
* monN, starting with mon0; as soon as one *doesn't* exist,
|
|
* it chooses that as the monitor device name. If the "iw"
|
|
* command exists, it does "iw dev {if} interface add {monif}
|
|
* type monitor", where {monif} is the monitor device. It
|
|
* then (sigh) sleeps .1 second, and then configures the
|
|
* device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface
|
|
* is a file, it writes {mondev}, without a newline, to that file,
|
|
* and again (sigh) sleeps .1 second, and then iwconfig's that
|
|
* device into monitor mode and configures it up. Otherwise,
|
|
* you can't do monitor mode.
|
|
*
|
|
* All these devices are "glued" together by having the
|
|
* /sys/class/net/{device}/phy80211 links pointing to the same
|
|
* place, so, given a wmaster, wlan, or mon device, you can
|
|
* find the other devices by looking for devices with
|
|
* the same phy80211 link.
|
|
*
|
|
* To turn monitor mode off, delete the monitor interface,
|
|
* either with "iw dev {monif} interface del" or by sending
|
|
* {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface
|
|
*
|
|
* Note: if you try to create a monitor device named "monN", and
|
|
* there's already a "monN" device, it fails, as least with
|
|
* the netlink interface (which is what iw uses), with a return
|
|
* value of -ENFILE. (Return values are negative errnos.) We
|
|
* could probably use that to find an unused device.
|
|
*/
|
|
int err;
|
|
struct iwreq ireq;
|
|
struct iw_priv_args *priv;
|
|
monitor_type montype;
|
|
int i;
|
|
__u32 cmd;
|
|
int args[2];
|
|
int channel;
|
|
|
|
/*
|
|
* Does this device *support* the Wireless Extensions?
|
|
*/
|
|
err = has_wext(sock_fd, device, handle->errbuf);
|
|
if (err <= 0)
|
|
return err; /* either it doesn't or the device doesn't even exist */
|
|
/*
|
|
* Try to get all the Wireless Extensions private ioctls
|
|
* supported by this device.
|
|
*
|
|
* First, get the size of the buffer we need, by supplying no
|
|
* buffer and a length of 0. If the device supports private
|
|
* ioctls, it should return E2BIG, with ireq.u.data.length set
|
|
* to the length we need. If it doesn't support them, it should
|
|
* return EOPNOTSUPP.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
ireq.u.data.pointer = (void *)args;
|
|
ireq.u.data.length = 0;
|
|
ireq.u.data.flags = 0;
|
|
if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: SIOCGIWPRIV with a zero-length buffer didn't fail!",
|
|
device);
|
|
return PCAP_ERROR;
|
|
}
|
|
if (errno == EOPNOTSUPP) {
|
|
/*
|
|
* No private ioctls, so we assume that there's only one
|
|
* DLT_ for monitor mode.
|
|
*/
|
|
return 0;
|
|
}
|
|
if (errno != E2BIG) {
|
|
/*
|
|
* Failed.
|
|
*/
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args));
|
|
if (priv == NULL) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"malloc: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
ireq.u.data.pointer = (void *)priv;
|
|
if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno));
|
|
free(priv);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* Look for private ioctls to turn monitor mode on or, if
|
|
* monitor mode is on, to set the header type.
|
|
*/
|
|
montype = MONITOR_WEXT;
|
|
cmd = 0;
|
|
for (i = 0; i < ireq.u.data.length; i++) {
|
|
if (strcmp(priv[i].name, "monitor_type") == 0) {
|
|
/*
|
|
* Hostap driver, use this one.
|
|
* Set monitor mode first.
|
|
* You can set it to 0 to get DLT_IEEE80211,
|
|
* 1 to get DLT_PRISM, 2 to get
|
|
* DLT_IEEE80211_RADIO_AVS, and, with more
|
|
* recent versions of the driver, 3 to get
|
|
* DLT_IEEE80211_RADIO.
|
|
*/
|
|
if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
|
|
break;
|
|
if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
|
|
break;
|
|
if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
|
|
break;
|
|
montype = MONITOR_HOSTAP;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
}
|
|
if (strcmp(priv[i].name, "set_prismhdr") == 0) {
|
|
/*
|
|
* Prism54 driver, use this one.
|
|
* Set monitor mode first.
|
|
* You can set it to 2 to get DLT_IEEE80211
|
|
* or 3 or get DLT_PRISM.
|
|
*/
|
|
if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
|
|
break;
|
|
if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
|
|
break;
|
|
if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
|
|
break;
|
|
montype = MONITOR_PRISM54;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
}
|
|
if (strcmp(priv[i].name, "forceprismheader") == 0) {
|
|
/*
|
|
* RT2570 driver, use this one.
|
|
* Do this after turning monitor mode on.
|
|
* You can set it to 1 to get DLT_PRISM or 2
|
|
* to get DLT_IEEE80211.
|
|
*/
|
|
if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
|
|
break;
|
|
if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
|
|
break;
|
|
if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
|
|
break;
|
|
montype = MONITOR_RT2570;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
}
|
|
if (strcmp(priv[i].name, "forceprism") == 0) {
|
|
/*
|
|
* RT73 driver, use this one.
|
|
* Do this after turning monitor mode on.
|
|
* Its argument is a *string*; you can
|
|
* set it to "1" to get DLT_PRISM or "2"
|
|
* to get DLT_IEEE80211.
|
|
*/
|
|
if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR)
|
|
break;
|
|
if (priv[i].set_args & IW_PRIV_SIZE_FIXED)
|
|
break;
|
|
montype = MONITOR_RT73;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
}
|
|
if (strcmp(priv[i].name, "prismhdr") == 0) {
|
|
/*
|
|
* One of the RTL8xxx drivers, use this one.
|
|
* It can only be done after monitor mode
|
|
* has been turned on. You can set it to 1
|
|
* to get DLT_PRISM or 0 to get DLT_IEEE80211.
|
|
*/
|
|
if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
|
|
break;
|
|
if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
|
|
break;
|
|
if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1)
|
|
break;
|
|
montype = MONITOR_RTL8XXX;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
}
|
|
if (strcmp(priv[i].name, "rfmontx") == 0) {
|
|
/*
|
|
* RT2500 or RT61 driver, use this one.
|
|
* It has one one-byte parameter; set
|
|
* u.data.length to 1 and u.data.pointer to
|
|
* point to the parameter.
|
|
* It doesn't itself turn monitor mode on.
|
|
* You can set it to 1 to allow transmitting
|
|
* in monitor mode(?) and get DLT_IEEE80211,
|
|
* or set it to 0 to disallow transmitting in
|
|
* monitor mode(?) and get DLT_PRISM.
|
|
*/
|
|
if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
|
|
break;
|
|
if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2)
|
|
break;
|
|
montype = MONITOR_RT2500;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
}
|
|
if (strcmp(priv[i].name, "monitor") == 0) {
|
|
/*
|
|
* Either ACX100 or hostap, use this one.
|
|
* It turns monitor mode on.
|
|
* If it takes two arguments, it's ACX100;
|
|
* the first argument is 1 for DLT_PRISM
|
|
* or 2 for DLT_IEEE80211, and the second
|
|
* argument is the channel on which to
|
|
* run. If it takes one argument, it's
|
|
* HostAP, and the argument is 2 for
|
|
* DLT_IEEE80211 and 3 for DLT_PRISM.
|
|
*
|
|
* If we see this, we don't quit, as this
|
|
* might be a version of the hostap driver
|
|
* that also supports "monitor_type".
|
|
*/
|
|
if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT)
|
|
break;
|
|
if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED))
|
|
break;
|
|
switch (priv[i].set_args & IW_PRIV_SIZE_MASK) {
|
|
|
|
case 1:
|
|
montype = MONITOR_PRISM;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
|
|
case 2:
|
|
montype = MONITOR_ACX100;
|
|
cmd = priv[i].cmd;
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
free(priv);
|
|
|
|
/*
|
|
* XXX - ipw3945? islism?
|
|
*/
|
|
|
|
/*
|
|
* Get the old mode.
|
|
*/
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
if (ioctl(sock_fd, SIOCGIWMODE, &ireq) == -1) {
|
|
/*
|
|
* We probably won't be able to set the mode, either.
|
|
*/
|
|
return PCAP_ERROR_RFMON_NOTSUP;
|
|
}
|
|
|
|
/*
|
|
* Is it currently in monitor mode?
|
|
*/
|
|
if (ireq.u.mode == IW_MODE_MONITOR) {
|
|
/*
|
|
* Yes. Just leave things as they are.
|
|
* We don't offer multiple link-layer types, as
|
|
* changing the link-layer type out from under
|
|
* somebody else capturing in monitor mode would
|
|
* be considered rude.
|
|
*/
|
|
return 1;
|
|
}
|
|
/*
|
|
* No. We have to put the adapter into rfmon mode.
|
|
*/
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
return PCAP_ERROR_RFMON_NOTSUP;
|
|
}
|
|
|
|
/*
|
|
* Save the old mode.
|
|
*/
|
|
handle->md.oldmode = ireq.u.mode;
|
|
|
|
/*
|
|
* Put the adapter in rfmon mode. How we do this depends
|
|
* on whether we have a special private ioctl or not.
|
|
*/
|
|
if (montype == MONITOR_PRISM) {
|
|
/*
|
|
* We have the "monitor" private ioctl, but none of
|
|
* the other private ioctls. Use this, and select
|
|
* the Prism header.
|
|
*
|
|
* If it fails, just fall back on SIOCSIWMODE.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
ireq.u.data.length = 1; /* 1 argument */
|
|
args[0] = 3; /* request Prism header */
|
|
memcpy(ireq.u.name, args, IFNAMSIZ);
|
|
if (ioctl(sock_fd, cmd, &ireq) != -1) {
|
|
/*
|
|
* Success.
|
|
* Note that we have to put the old mode back
|
|
* when we close the device.
|
|
*/
|
|
handle->md.must_do_on_close |= MUST_CLEAR_RFMON;
|
|
|
|
/*
|
|
* Add this to the list of pcaps to close
|
|
* when we exit.
|
|
*/
|
|
pcap_add_to_pcaps_to_close(handle);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Failure. Fall back on SIOCSIWMODE.
|
|
*/
|
|
}
|
|
|
|
/*
|
|
* First, turn monitor mode on.
|
|
*/
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
ireq.u.mode = IW_MODE_MONITOR;
|
|
if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) {
|
|
/*
|
|
* Scientist, you've failed.
|
|
*/
|
|
return PCAP_ERROR_RFMON_NOTSUP;
|
|
}
|
|
|
|
/*
|
|
* XXX - airmon-ng does "iwconfig {if} key off" after setting
|
|
* monitor mode and setting the channel, and then does
|
|
* "iwconfig up".
|
|
*/
|
|
|
|
/*
|
|
* Now select the appropriate radio header.
|
|
*/
|
|
switch (montype) {
|
|
|
|
case MONITOR_WEXT:
|
|
/*
|
|
* We don't have any private ioctl to set the header.
|
|
*/
|
|
break;
|
|
|
|
case MONITOR_HOSTAP:
|
|
/*
|
|
* Try to select the radiotap header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 3; /* request radiotap header */
|
|
memcpy(ireq.u.name, args, sizeof (int));
|
|
if (ioctl(sock_fd, cmd, &ireq) != -1)
|
|
break; /* success */
|
|
|
|
/*
|
|
* That failed. Try to select the AVS header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 2; /* request AVS header */
|
|
memcpy(ireq.u.name, args, sizeof (int));
|
|
if (ioctl(sock_fd, cmd, &ireq) != -1)
|
|
break; /* success */
|
|
|
|
/*
|
|
* That failed. Try to select the Prism header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 1; /* request Prism header */
|
|
memcpy(ireq.u.name, args, sizeof (int));
|
|
ioctl(sock_fd, cmd, &ireq);
|
|
break;
|
|
|
|
case MONITOR_PRISM:
|
|
/*
|
|
* The private ioctl failed.
|
|
*/
|
|
break;
|
|
|
|
case MONITOR_PRISM54:
|
|
/*
|
|
* Select the Prism header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 3; /* request Prism header */
|
|
memcpy(ireq.u.name, args, sizeof (int));
|
|
ioctl(sock_fd, cmd, &ireq);
|
|
break;
|
|
|
|
case MONITOR_ACX100:
|
|
/*
|
|
* Get the current channel.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
if (ioctl(sock_fd, SIOCGIWFREQ, &ireq) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"%s: SIOCGIWFREQ: %s", device,
|
|
pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
channel = ireq.u.freq.m;
|
|
|
|
/*
|
|
* Select the Prism header, and set the channel to the
|
|
* current value.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 1; /* request Prism header */
|
|
args[1] = channel; /* set channel */
|
|
memcpy(ireq.u.name, args, 2*sizeof (int));
|
|
ioctl(sock_fd, cmd, &ireq);
|
|
break;
|
|
|
|
case MONITOR_RT2500:
|
|
/*
|
|
* Disallow transmission - that turns on the
|
|
* Prism header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 0; /* disallow transmitting */
|
|
memcpy(ireq.u.name, args, sizeof (int));
|
|
ioctl(sock_fd, cmd, &ireq);
|
|
break;
|
|
|
|
case MONITOR_RT2570:
|
|
/*
|
|
* Force the Prism header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 1; /* request Prism header */
|
|
memcpy(ireq.u.name, args, sizeof (int));
|
|
ioctl(sock_fd, cmd, &ireq);
|
|
break;
|
|
|
|
case MONITOR_RT73:
|
|
/*
|
|
* Force the Prism header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
ireq.u.data.length = 1; /* 1 argument */
|
|
ireq.u.data.pointer = "1";
|
|
ireq.u.data.flags = 0;
|
|
ioctl(sock_fd, cmd, &ireq);
|
|
break;
|
|
|
|
case MONITOR_RTL8XXX:
|
|
/*
|
|
* Force the Prism header.
|
|
*/
|
|
memset(&ireq, 0, sizeof ireq);
|
|
strncpy(ireq.ifr_ifrn.ifrn_name, device,
|
|
sizeof ireq.ifr_ifrn.ifrn_name);
|
|
ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0;
|
|
args[0] = 1; /* request Prism header */
|
|
memcpy(ireq.u.name, args, sizeof (int));
|
|
ioctl(sock_fd, cmd, &ireq);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Note that we have to put the old mode back when we
|
|
* close the device.
|
|
*/
|
|
handle->md.must_do_on_close |= MUST_CLEAR_RFMON;
|
|
|
|
/*
|
|
* Add this to the list of pcaps to close when we exit.
|
|
*/
|
|
pcap_add_to_pcaps_to_close(handle);
|
|
|
|
return 1;
|
|
}
|
|
#endif /* IW_MODE_MONITOR */
|
|
|
|
/*
|
|
* Try various mechanisms to enter monitor mode.
|
|
*/
|
|
static int
|
|
enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device)
|
|
{
|
|
#if defined(HAVE_LIBNL) || defined(IW_MODE_MONITOR)
|
|
int ret;
|
|
#endif
|
|
|
|
#ifdef HAVE_LIBNL
|
|
ret = enter_rfmon_mode_mac80211(handle, sock_fd, device);
|
|
if (ret < 0)
|
|
return ret; /* error attempting to do so */
|
|
if (ret == 1)
|
|
return 1; /* success */
|
|
#endif /* HAVE_LIBNL */
|
|
|
|
#ifdef IW_MODE_MONITOR
|
|
ret = enter_rfmon_mode_wext(handle, sock_fd, device);
|
|
if (ret < 0)
|
|
return ret; /* error attempting to do so */
|
|
if (ret == 1)
|
|
return 1; /* success */
|
|
#endif /* IW_MODE_MONITOR */
|
|
|
|
/*
|
|
* Either none of the mechanisms we know about work or none
|
|
* of those mechanisms are available, so we can't do monitor
|
|
* mode.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
#endif /* HAVE_PF_PACKET_SOCKETS */
|
|
|
|
/* ===== Functions to interface to the older kernels ================== */
|
|
|
|
/*
|
|
* Try to open a packet socket using the old kernel interface.
|
|
* Returns 1 on success and a PCAP_ERROR_ value on an error.
|
|
*/
|
|
static int
|
|
activate_old(pcap_t *handle)
|
|
{
|
|
int arptype;
|
|
struct ifreq ifr;
|
|
const char *device = handle->opt.source;
|
|
struct utsname utsname;
|
|
int mtu;
|
|
|
|
/* Open the socket */
|
|
|
|
handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL));
|
|
if (handle->fd == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"socket: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR_PERM_DENIED;
|
|
}
|
|
|
|
/* It worked - we are using the old interface */
|
|
handle->md.sock_packet = 1;
|
|
|
|
/* ...which means we get the link-layer header. */
|
|
handle->md.cooked = 0;
|
|
|
|
/* Bind to the given device */
|
|
|
|
if (strcmp(device, "any") == 0) {
|
|
strncpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems",
|
|
PCAP_ERRBUF_SIZE);
|
|
return PCAP_ERROR;
|
|
}
|
|
if (iface_bind_old(handle->fd, device, handle->errbuf) == -1)
|
|
return PCAP_ERROR;
|
|
|
|
/*
|
|
* Try to get the link-layer type.
|
|
*/
|
|
arptype = iface_get_arptype(handle->fd, device, handle->errbuf);
|
|
if (arptype < 0)
|
|
return PCAP_ERROR;
|
|
|
|
/*
|
|
* Try to find the DLT_ type corresponding to that
|
|
* link-layer type.
|
|
*/
|
|
map_arphrd_to_dlt(handle, arptype, 0);
|
|
if (handle->linktype == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"unknown arptype %d", arptype);
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
/* Go to promisc mode if requested */
|
|
|
|
if (handle->opt.promisc) {
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGIFFLAGS: %s", pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
if ((ifr.ifr_flags & IFF_PROMISC) == 0) {
|
|
/*
|
|
* Promiscuous mode isn't currently on,
|
|
* so turn it on, and remember that
|
|
* we should turn it off when the
|
|
* pcap_t is closed.
|
|
*/
|
|
|
|
/*
|
|
* 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 promiscuous
|
|
* mode, just give up.
|
|
*/
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
ifr.ifr_flags |= IFF_PROMISC;
|
|
if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCSIFFLAGS: %s",
|
|
pcap_strerror(errno));
|
|
return PCAP_ERROR;
|
|
}
|
|
handle->md.must_do_on_close |= MUST_CLEAR_PROMISC;
|
|
|
|
/*
|
|
* Add this to the list of pcaps
|
|
* to close when we exit.
|
|
*/
|
|
pcap_add_to_pcaps_to_close(handle);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Compute the buffer size.
|
|
*
|
|
* We're using SOCK_PACKET, so this might be a 2.0[.x]
|
|
* kernel, and might require special handling - check.
|
|
*/
|
|
if (uname(&utsname) < 0 ||
|
|
strncmp(utsname.release, "2.0", 3) == 0) {
|
|
/*
|
|
* Either we couldn't find out what kernel release
|
|
* this is, or it's a 2.0[.x] kernel.
|
|
*
|
|
* In the 2.0[.x] kernel, a "recvfrom()" on
|
|
* a SOCK_PACKET socket, with MSG_TRUNC set, will
|
|
* return the number of bytes read, so if we pass
|
|
* a length based on the snapshot length, it'll
|
|
* return the number of bytes from the packet
|
|
* copied to userland, not the actual length
|
|
* of the packet.
|
|
*
|
|
* This means that, for example, the IP dissector
|
|
* in tcpdump will get handed a packet length less
|
|
* than the length in the IP header, and will
|
|
* complain about "truncated-ip".
|
|
*
|
|
* So we don't bother trying to copy from the
|
|
* kernel only the bytes in which we're interested,
|
|
* but instead copy them all, just as the older
|
|
* versions of libpcap for Linux did.
|
|
*
|
|
* The buffer therefore needs to be big enough to
|
|
* hold the largest packet we can get from this
|
|
* device. Unfortunately, we can't get the MRU
|
|
* of the network; we can only get the MTU. The
|
|
* MTU may be too small, in which case a packet larger
|
|
* than the buffer size will be truncated *and* we
|
|
* won't get the actual packet size.
|
|
*
|
|
* However, if the snapshot length is larger than
|
|
* the buffer size based on the MTU, we use the
|
|
* snapshot length as the buffer size, instead;
|
|
* this means that with a sufficiently large snapshot
|
|
* length we won't artificially truncate packets
|
|
* to the MTU-based size.
|
|
*
|
|
* This mess just one of many problems with packet
|
|
* capture on 2.0[.x] kernels; you really want a
|
|
* 2.2[.x] or later kernel if you want packet capture
|
|
* to work well.
|
|
*/
|
|
mtu = iface_get_mtu(handle->fd, device, handle->errbuf);
|
|
if (mtu == -1)
|
|
return PCAP_ERROR;
|
|
handle->bufsize = MAX_LINKHEADER_SIZE + mtu;
|
|
if (handle->bufsize < handle->snapshot)
|
|
handle->bufsize = handle->snapshot;
|
|
} else {
|
|
/*
|
|
* This is a 2.2[.x] or later kernel.
|
|
*
|
|
* We can safely pass "recvfrom()" a byte count
|
|
* based on the snapshot length.
|
|
*/
|
|
handle->bufsize = handle->snapshot;
|
|
}
|
|
|
|
/*
|
|
* Default value for offset to align link-layer payload
|
|
* on a 4-byte boundary.
|
|
*/
|
|
handle->offset = 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Bind the socket associated with FD to the given device using the
|
|
* interface of the old kernels.
|
|
*/
|
|
static int
|
|
iface_bind_old(int fd, const char *device, char *ebuf)
|
|
{
|
|
struct sockaddr saddr;
|
|
int err;
|
|
socklen_t errlen = sizeof(err);
|
|
|
|
memset(&saddr, 0, sizeof(saddr));
|
|
strncpy(saddr.sa_data, device, sizeof(saddr.sa_data));
|
|
if (bind(fd, &saddr, sizeof(saddr)) == -1) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"bind: %s", pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
/* Any pending errors, e.g., network is down? */
|
|
|
|
if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"getsockopt: %s", pcap_strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
if (err > 0) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"bind: %s", pcap_strerror(err));
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* ===== System calls available on all supported kernels ============== */
|
|
|
|
/*
|
|
* 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));
|
|
strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
|
|
if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGIFMTU: %s", pcap_strerror(errno));
|
|
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;
|
|
|
|
memset(&ifr, 0, sizeof(ifr));
|
|
strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
|
|
|
|
if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
|
|
snprintf(ebuf, PCAP_ERRBUF_SIZE,
|
|
"SIOCGIFHWADDR: %s", pcap_strerror(errno));
|
|
if (errno == ENODEV) {
|
|
/*
|
|
* No such device.
|
|
*/
|
|
return PCAP_ERROR_NO_SUCH_DEVICE;
|
|
}
|
|
return PCAP_ERROR;
|
|
}
|
|
|
|
return ifr.ifr_hwaddr.sa_family;
|
|
}
|
|
|
|
#ifdef SO_ATTACH_FILTER
|
|
static int
|
|
fix_program(pcap_t *handle, struct sock_fprog *fcode, int is_mmapped)
|
|
{
|
|
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) {
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"malloc: %s", pcap_strerror(errno));
|
|
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_RET:
|
|
/*
|
|
* It's a return instruction; are we capturing
|
|
* in memory-mapped mode?
|
|
*/
|
|
if (!is_mmapped) {
|
|
/*
|
|
* No; is the snapshot length a constant,
|
|
* rather than the contents of the
|
|
* accumulator?
|
|
*/
|
|
if (BPF_MODE(p->code) == BPF_K) {
|
|
/*
|
|
* Yes - if the value to be returned,
|
|
* i.e. the snapshot length, is
|
|
* anything other than 0, make it
|
|
* 65535, so that the packet is
|
|
* truncated by "recvfrom()",
|
|
* not by the filter.
|
|
*
|
|
* XXX - there's nothing we can
|
|
* easily do if it's getting the
|
|
* value from the accumulator; we'd
|
|
* have to insert code to force
|
|
* non-zero values to be 65535.
|
|
*/
|
|
if (p->k != 0)
|
|
p->k = 65535;
|
|
}
|
|
}
|
|
break;
|
|
|
|
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 (handle->md.cooked) {
|
|
/*
|
|
* Yes, so we need to fix this
|
|
* instruction.
|
|
*/
|
|
if (fix_offset(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(struct bpf_insn *p)
|
|
{
|
|
/*
|
|
* 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 == 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 {
|
|
/*
|
|
* 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 &&
|
|
fcntl(handle->fd, F_SETFL, save_mode | O_NONBLOCK) >= 0) {
|
|
while (recv(handle->fd, &drain, sizeof drain,
|
|
MSG_TRUNC) >= 0)
|
|
;
|
|
save_errno = errno;
|
|
fcntl(handle->fd, F_SETFL, save_mode);
|
|
if (save_errno != EAGAIN) {
|
|
/* Fatal error */
|
|
reset_kernel_filter(handle);
|
|
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
|
|
"recv: %s", pcap_strerror(save_errno));
|
|
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;
|
|
|
|
/*
|
|
* XXX - if this fails, we're really screwed;
|
|
* we have the total filter on the socket,
|
|
* and it won't come off. What do we do then?
|
|
*/
|
|
reset_kernel_filter(handle);
|
|
|
|
errno = save_errno;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
reset_kernel_filter(pcap_t *handle)
|
|
{
|
|
/*
|
|
* 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;
|
|
|
|
return setsockopt(handle->fd, SOL_SOCKET, SO_DETACH_FILTER,
|
|
&dummy, sizeof(dummy));
|
|
}
|
|
#endif
|