420 lines
11 KiB
C
420 lines
11 KiB
C
/*
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* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
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* The Regents of the University of California. 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: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* Modifications made to accommodate the new SunOS4.0 NIT facility by
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* Micky Liu, micky@cunixc.cc.columbia.edu, Columbia University in May, 1989.
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* This module now handles the STREAMS based NIT.
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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-snit.c,v 1.72.2.1 2005/05/03 18:54:38 guy Exp $ (LBL)";
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#endif
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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 <sys/types.h>
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#include <sys/time.h>
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#include <sys/timeb.h>
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#include <sys/dir.h>
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#include <sys/fcntlcom.h>
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#include <sys/file.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <sys/stropts.h>
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#include <net/if.h>
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#include <net/nit.h>
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#include <net/nit_if.h>
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#include <net/nit_pf.h>
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#include <net/nit_buf.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/if_ether.h>
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#include <netinet/ip_var.h>
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#include <netinet/udp.h>
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#include <netinet/udp_var.h>
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#include <netinet/tcp.h>
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#include <netinet/tcpip.h>
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#include <ctype.h>
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include "pcap-int.h"
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#ifdef HAVE_OS_PROTO_H
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#include "os-proto.h"
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#endif
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/*
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* The chunk size for NIT. This is the amount of buffering
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* done for read calls.
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*/
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#define CHUNKSIZE (2*1024)
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/*
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* The total buffer space used by NIT.
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*/
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#define BUFSPACE (4*CHUNKSIZE)
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/* Forwards */
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static int nit_setflags(int, int, int, char *);
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static int
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pcap_stats_snit(pcap_t *p, struct pcap_stat *ps)
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{
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/*
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* "ps_recv" counts packets handed to the filter, not packets
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* that passed the filter. As filtering is done in userland,
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* this does not include packets dropped because we ran out
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* of buffer space.
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*
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* "ps_drop" counts packets dropped inside the "/dev/nit"
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* device because of flow control requirements or resource
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* exhaustion; it doesn't count packets dropped by the
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* interface driver, or packets dropped upstream. As filtering
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* is done in userland, it counts packets regardless of whether
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* they would've passed the filter.
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*
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* These statistics don't include packets not yet read from the
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* kernel by libpcap or packets not yet read from libpcap by the
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* application.
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*/
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*ps = p->md.stat;
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return (0);
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}
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static int
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pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
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{
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register int cc, n;
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register struct bpf_insn *fcode = p->fcode.bf_insns;
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register u_char *bp, *cp, *ep;
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register struct nit_bufhdr *hdrp;
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register struct nit_iftime *ntp;
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register struct nit_iflen *nlp;
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register struct nit_ifdrops *ndp;
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register int caplen;
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cc = p->cc;
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if (cc == 0) {
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cc = read(p->fd, (char *)p->buffer, p->bufsize);
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if (cc < 0) {
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if (errno == EWOULDBLOCK)
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return (0);
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snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
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pcap_strerror(errno));
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return (-1);
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}
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bp = p->buffer;
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} else
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bp = p->bp;
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/*
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* loop through each snapshot in the chunk
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*/
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n = 0;
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ep = bp + cc;
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while (bp < ep) {
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/*
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* Has "pcap_breakloop()" been called?
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* If so, return immediately - if we haven't read any
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* packets, clear the flag and return -2 to indicate
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* that we were told to break out of the loop, otherwise
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* leave the flag set, so that the *next* call will break
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* out of the loop without having read any packets, and
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* return the number of packets we've processed so far.
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*/
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if (p->break_loop) {
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if (n == 0) {
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p->break_loop = 0;
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return (-2);
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} else {
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p->bp = bp;
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p->cc = ep - bp;
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return (n);
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}
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}
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++p->md.stat.ps_recv;
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cp = bp;
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/* get past NIT buffer */
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hdrp = (struct nit_bufhdr *)cp;
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cp += sizeof(*hdrp);
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/* get past NIT timer */
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ntp = (struct nit_iftime *)cp;
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cp += sizeof(*ntp);
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ndp = (struct nit_ifdrops *)cp;
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p->md.stat.ps_drop = ndp->nh_drops;
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cp += sizeof *ndp;
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/* get past packet len */
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nlp = (struct nit_iflen *)cp;
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cp += sizeof(*nlp);
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/* next snapshot */
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bp += hdrp->nhb_totlen;
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caplen = nlp->nh_pktlen;
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if (caplen > p->snapshot)
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caplen = p->snapshot;
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if (bpf_filter(fcode, cp, nlp->nh_pktlen, caplen)) {
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struct pcap_pkthdr h;
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h.ts = ntp->nh_timestamp;
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h.len = nlp->nh_pktlen;
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h.caplen = caplen;
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(*callback)(user, &h, cp);
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if (++n >= cnt && cnt >= 0) {
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p->cc = ep - bp;
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p->bp = bp;
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return (n);
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}
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}
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}
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p->cc = 0;
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return (n);
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}
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static int
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pcap_inject_snit(pcap_t *p, const void *buf, size_t size)
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{
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struct strbuf ctl, data;
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/*
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* XXX - can we just do
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*
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ret = write(pd->f, buf, size);
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*/
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ctl.len = sizeof(*sa); /* XXX - what was this? */
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ctl.buf = (char *)sa;
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data.buf = buf;
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data.len = size;
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ret = putmsg(p->fd, &ctl, &data);
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if (ret == -1) {
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snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
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pcap_strerror(errno));
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return (-1);
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}
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return (ret);
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}
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static int
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nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
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{
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bpf_u_int32 flags;
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struct strioctl si;
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struct timeval timeout;
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si.ic_timout = INFTIM;
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if (to_ms != 0) {
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timeout.tv_sec = to_ms / 1000;
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timeout.tv_usec = (to_ms * 1000) % 1000000;
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si.ic_cmd = NIOCSTIME;
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si.ic_len = sizeof(timeout);
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si.ic_dp = (char *)&timeout;
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if (ioctl(fd, I_STR, (char *)&si) < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
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pcap_strerror(errno));
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return (-1);
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}
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}
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flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
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if (promisc)
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flags |= NI_PROMISC;
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si.ic_cmd = NIOCSFLAGS;
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si.ic_len = sizeof(flags);
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si.ic_dp = (char *)&flags;
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if (ioctl(fd, I_STR, (char *)&si) < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
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pcap_strerror(errno));
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return (-1);
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}
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return (0);
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}
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pcap_t *
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pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
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char *ebuf)
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{
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struct strioctl si; /* struct for ioctl() */
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struct ifreq ifr; /* interface request struct */
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int chunksize = CHUNKSIZE;
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int fd;
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static char dev[] = "/dev/nit";
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register pcap_t *p;
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p = (pcap_t *)malloc(sizeof(*p));
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if (p == NULL) {
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strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
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return (NULL);
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}
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if (snaplen < 96)
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/*
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* NIT requires a snapshot length of at least 96.
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*/
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snaplen = 96;
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memset(p, 0, sizeof(*p));
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/*
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* Initially try a read/write open (to allow the inject
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* method to work). If that fails due to permission
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* issues, fall back to read-only. This allows a
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* non-root user to be granted specific access to pcap
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* capabilities via file permissions.
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*
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* XXX - we should have an API that has a flag that
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* controls whether to open read-only or read-write,
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* so that denial of permission to send (or inability
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* to send, if sending packets isn't supported on
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* the device in question) can be indicated at open
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* time.
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*/
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p->fd = fd = open(dev, O_RDWR);
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if (fd < 0 && errno == EACCES)
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p->fd = fd = open(dev, O_RDONLY);
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if (fd < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
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pcap_strerror(errno));
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goto bad;
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}
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/* arrange to get discrete messages from the STREAM and use NIT_BUF */
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if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
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pcap_strerror(errno));
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goto bad;
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}
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if (ioctl(fd, I_PUSH, "nbuf") < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
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pcap_strerror(errno));
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goto bad;
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}
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/* set the chunksize */
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si.ic_cmd = NIOCSCHUNK;
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si.ic_timout = INFTIM;
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si.ic_len = sizeof(chunksize);
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si.ic_dp = (char *)&chunksize;
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if (ioctl(fd, I_STR, (char *)&si) < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
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pcap_strerror(errno));
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goto bad;
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}
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/* request the interface */
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strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
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ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
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si.ic_cmd = NIOCBIND;
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si.ic_len = sizeof(ifr);
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si.ic_dp = (char *)𝔦
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if (ioctl(fd, I_STR, (char *)&si) < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
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ifr.ifr_name, pcap_strerror(errno));
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goto bad;
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}
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/* set the snapshot length */
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si.ic_cmd = NIOCSSNAP;
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si.ic_len = sizeof(snaplen);
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si.ic_dp = (char *)&snaplen;
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if (ioctl(fd, I_STR, (char *)&si) < 0) {
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snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
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pcap_strerror(errno));
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goto bad;
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}
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p->snapshot = snaplen;
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if (nit_setflags(p->fd, promisc, to_ms, ebuf) < 0)
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goto bad;
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(void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
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/*
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* NIT supports only ethernets.
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*/
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p->linktype = DLT_EN10MB;
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p->bufsize = BUFSPACE;
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p->buffer = (u_char *)malloc(p->bufsize);
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if (p->buffer == NULL) {
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strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
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goto bad;
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}
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/*
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* "p->fd" is an FD for a STREAMS device, so "select()" and
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* "poll()" should work on it.
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*/
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p->selectable_fd = p->fd;
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/*
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* This is (presumably) a real Ethernet capture; give it a
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* link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
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* that an application can let you choose it, in case you're
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* capturing DOCSIS traffic that a Cisco Cable Modem
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* Termination System is putting out onto an Ethernet (it
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* doesn't put an Ethernet header onto the wire, it puts raw
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* DOCSIS frames out on the wire inside the low-level
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* Ethernet framing).
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*/
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p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
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/*
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* If that fails, just leave the list empty.
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*/
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if (p->dlt_list != NULL) {
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p->dlt_list[0] = DLT_EN10MB;
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p->dlt_list[1] = DLT_DOCSIS;
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p->dlt_count = 2;
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}
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p->read_op = pcap_read_snit;
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p->inject_op = pcap_inject_snit;
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p->setfilter_op = install_bpf_program; /* no kernel filtering */
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p->setdirection_op = NULL; /* Not implemented. */
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p->set_datalink_op = NULL; /* can't change data link type */
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p->getnonblock_op = pcap_getnonblock_fd;
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p->setnonblock_op = pcap_setnonblock_fd;
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p->stats_op = pcap_stats_snit;
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p->close_op = pcap_close_common;
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return (p);
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bad:
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if (fd >= 0)
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close(fd);
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free(p);
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return (NULL);
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}
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int
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pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
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{
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return (0);
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}
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