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-rw-r--r--pcap-pf.c351
1 files changed, 351 insertions, 0 deletions
diff --git a/pcap-pf.c b/pcap-pf.c
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+/*
+ * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code distributions
+ * retain the above copyright notice and this paragraph in its entirety, (2)
+ * distributions including binary code include the above copyright notice and
+ * this paragraph in its entirety in the documentation or other materials
+ * provided with the distribution, and (3) all advertising materials mentioning
+ * features or use of this software display the following acknowledgement:
+ * ``This product includes software developed by the University of California,
+ * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+ * the University nor the names of its contributors may be used to endorse
+ * or promote products derived from this software without specific prior
+ * written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * packet filter subroutines for tcpdump
+ * Extraction/creation by Jeffrey Mogul, DECWRL
+ */
+
+#ifndef lint
+static const char rcsid[] =
+ "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.54 1999-10-07 23:46:40 mcr Exp $ (LBL)";
+#endif
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/timeb.h>
+#include <sys/socket.h>
+#include <sys/file.h>
+#include <sys/ioctl.h>
+#include <net/pfilt.h>
+
+#if __STDC__
+struct mbuf;
+struct rtentry;
+#endif
+
+#include <net/if.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/if_ether.h>
+#include <netinet/ip_var.h>
+#include <netinet/udp.h>
+#include <netinet/udp_var.h>
+#include <netinet/tcp.h>
+#include <netinet/tcpip.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "pcap-int.h"
+
+#include "gnuc.h"
+#ifdef HAVE_OS_PROTO_H
+#include "os-proto.h"
+#endif
+
+/*
+ * BUFSPACE is the size in bytes of the packet read buffer. Most tcpdump
+ * applications aren't going to need more than 200 bytes of packet header
+ * and the read shouldn't return more packets than packetfilter's internal
+ * queue limit (bounded at 256).
+ */
+#define BUFSPACE (200 * 256)
+
+int
+pcap_read(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)
+{
+ register u_char *p, *bp;
+ struct bpf_insn *fcode;
+ register int cc, n, buflen, inc;
+ register struct enstamp *sp;
+#ifdef LBL_ALIGN
+ struct enstamp stamp;
+#endif
+#ifdef PCAP_FDDIPAD
+ register int pad;
+#endif
+
+ fcode = pc->md.use_bpf ? NULL : pc->fcode.bf_insns;
+ again:
+ cc = pc->cc;
+ if (cc == 0) {
+ cc = read(pc->fd, (char *)pc->buffer + pc->offset, pc->bufsize);
+ if (cc < 0) {
+ if (errno == EWOULDBLOCK)
+ return (0);
+ if (errno == EINVAL &&
+ lseek(pc->fd, 0L, SEEK_CUR) + pc->bufsize < 0) {
+ /*
+ * Due to a kernel bug, after 2^31 bytes,
+ * the kernel file offset overflows and
+ * read fails with EINVAL. The lseek()
+ * to 0 will fix things.
+ */
+ (void)lseek(pc->fd, 0L, SEEK_SET);
+ goto again;
+ }
+ sprintf(pc->errbuf, "pf read: %s",
+ pcap_strerror(errno));
+ return (-1);
+ }
+ bp = pc->buffer + pc->offset;
+ } else
+ bp = pc->bp;
+ /*
+ * Loop through each packet.
+ */
+ n = 0;
+#ifdef PCAP_FDDIPAD
+ if (pc->linktype == DLT_FDDI)
+ pad = pcap_fddipad;
+ else
+ pad = 0;
+#endif
+ while (cc > 0) {
+ if (cc < sizeof(*sp)) {
+ sprintf(pc->errbuf, "pf short read (%d)", cc);
+ return (-1);
+ }
+#ifdef LBL_ALIGN
+ if ((long)bp & 3) {
+ sp = &stamp;
+ memcpy((char *)sp, (char *)bp, sizeof(*sp));
+ } else
+#endif
+ sp = (struct enstamp *)bp;
+ if (sp->ens_stamplen != sizeof(*sp)) {
+ sprintf(pc->errbuf, "pf short stamplen (%d)",
+ sp->ens_stamplen);
+ return (-1);
+ }
+
+ p = bp + sp->ens_stamplen;
+ buflen = sp->ens_count;
+ if (buflen > pc->snapshot)
+ buflen = pc->snapshot;
+
+ /* Calculate inc before possible pad update */
+ inc = ENALIGN(buflen + sp->ens_stamplen);
+ cc -= inc;
+ bp += inc;
+#ifdef PCAP_FDDIPAD
+ p += pad;
+ buflen -= pad;
+#endif
+ pc->md.TotPkts++;
+ pc->md.TotDrops += sp->ens_dropped;
+ pc->md.TotMissed = sp->ens_ifoverflows;
+ if (pc->md.OrigMissed < 0)
+ pc->md.OrigMissed = pc->md.TotMissed;
+
+ /*
+ * Short-circuit evaluation: if using BPF filter
+ * in kernel, no need to do it now.
+ */
+ if (fcode == NULL ||
+ bpf_filter(fcode, p, sp->ens_count, buflen)) {
+ struct pcap_pkthdr h;
+ pc->md.TotAccepted++;
+ h.ts = sp->ens_tstamp;
+#ifdef PCAP_FDDIPAD
+ h.len = sp->ens_count - pad;
+#else
+ h.len = sp->ens_count;
+#endif
+ h.caplen = buflen;
+ (*callback)(user, &h, p);
+ if (++n >= cnt && cnt > 0) {
+ pc->cc = cc;
+ pc->bp = bp;
+ return (n);
+ }
+ }
+ }
+ pc->cc = 0;
+ return (n);
+}
+
+int
+pcap_stats(pcap_t *p, struct pcap_stat *ps)
+{
+
+ ps->ps_recv = p->md.TotAccepted;
+ ps->ps_drop = p->md.TotDrops;
+ ps->ps_ifdrop = p->md.TotMissed - p->md.OrigMissed;
+ return (0);
+}
+
+pcap_t *
+pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
+{
+ pcap_t *p;
+ short enmode;
+ int backlog = -1; /* request the most */
+ struct enfilter Filter;
+ struct endevp devparams;
+
+ p = (pcap_t *)malloc(sizeof(*p));
+ if (p == NULL) {
+ sprintf(ebuf, "pcap_open_live: %s", pcap_strerror(errno));
+ return (0);
+ }
+ bzero((char *)p, sizeof(*p));
+ p->fd = pfopen(device, O_RDONLY);
+ if (p->fd < 0) {
+ sprintf(ebuf, "pf open: %s: %s\n\
+your system may not be properly configured; see \"man packetfilter(4)\"\n",
+ device, pcap_strerror(errno));
+ goto bad;
+ }
+ p->md.OrigMissed = -1;
+ enmode = ENTSTAMP|ENBATCH|ENNONEXCL;
+ if (promisc)
+ enmode |= ENPROMISC;
+ if (ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode) < 0) {
+ sprintf(ebuf, "EIOCMBIS: %s", pcap_strerror(errno));
+ goto bad;
+ }
+#ifdef ENCOPYALL
+ /* Try to set COPYALL mode so that we see packets to ourself */
+ enmode = ENCOPYALL;
+ (void)ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode);/* OK if this fails */
+#endif
+ /* set the backlog */
+ if (ioctl(p->fd, EIOCSETW, (caddr_t)&backlog) < 0) {
+ sprintf(ebuf, "EIOCSETW: %s", pcap_strerror(errno));
+ goto bad;
+ }
+ /* discover interface type */
+ if (ioctl(p->fd, EIOCDEVP, (caddr_t)&devparams) < 0) {
+ sprintf(ebuf, "EIOCDEVP: %s", pcap_strerror(errno));
+ goto bad;
+ }
+ /* HACK: to compile prior to Ultrix 4.2 */
+#ifndef ENDT_FDDI
+#define ENDT_FDDI 4
+#endif
+ switch (devparams.end_dev_type) {
+
+ case ENDT_10MB:
+ p->linktype = DLT_EN10MB;
+ p->offset = 2;
+ break;
+
+ case ENDT_FDDI:
+ p->linktype = DLT_FDDI;
+ break;
+
+ default:
+ /*
+ * XXX
+ * Currently, the Ultrix packet filter supports only
+ * Ethernet and FDDI. Eventually, support for SLIP and PPP
+ * (and possibly others: T1?) should be added.
+ */
+#ifdef notdef
+ warning(
+ "Packet filter data-link type %d unknown, assuming Ethernet",
+ devparams.end_dev_type);
+#endif
+ p->linktype = DLT_EN10MB;
+ p->offset = 2;
+ break;
+ }
+ /* set truncation */
+#ifdef PCAP_FDDIPAD
+ if (p->linktype == DLT_FDDI)
+ /* packetfilter includes the padding in the snapshot */
+ snaplen += pcap_fddipad;
+#endif
+ if (ioctl(p->fd, EIOCTRUNCATE, (caddr_t)&snaplen) < 0) {
+ sprintf(ebuf, "EIOCTRUNCATE: %s", pcap_strerror(errno));
+ goto bad;
+ }
+ p->snapshot = snaplen;
+ /* accept all packets */
+ bzero((char *)&Filter, sizeof(Filter));
+ Filter.enf_Priority = 37; /* anything > 2 */
+ Filter.enf_FilterLen = 0; /* means "always true" */
+ if (ioctl(p->fd, EIOCSETF, (caddr_t)&Filter) < 0) {
+ sprintf(ebuf, "EIOCSETF: %s", pcap_strerror(errno));
+ goto bad;
+ }
+
+ if (to_ms != 0) {
+ struct timeval timeout;
+ timeout.tv_sec = to_ms / 1000;
+ timeout.tv_usec = (to_ms * 1000) % 1000000;
+ if (ioctl(p->fd, EIOCSRTIMEOUT, (caddr_t)&timeout) < 0) {
+ sprintf(ebuf, "EIOCSRTIMEOUT: %s",
+ pcap_strerror(errno));
+ goto bad;
+ }
+ }
+ p->bufsize = BUFSPACE;
+ p->buffer = (u_char*)malloc(p->bufsize + p->offset);
+
+ return (p);
+ bad:
+ free(p);
+ return (NULL);
+}
+
+int
+pcap_setfilter(pcap_t *p, struct bpf_program *fp)
+{
+ /*
+ * See if BIOCSETF works. If it does, the kernel supports
+ * BPF-style filters, and we do not need to do post-filtering.
+ */
+ p->md.use_bpf = (ioctl(p->fd, BIOCSETF, (caddr_t)fp) >= 0);
+ if (p->md.use_bpf) {
+ struct bpf_version bv;
+
+ if (ioctl(p->fd, BIOCVERSION, (caddr_t)&bv) < 0) {
+ sprintf(p->errbuf, "BIOCVERSION: %s",
+ pcap_strerror(errno));
+ return (-1);
+ }
+ else if (bv.bv_major != BPF_MAJOR_VERSION ||
+ bv.bv_minor < BPF_MINOR_VERSION) {
+ fprintf(stderr,
+ "requires bpf language %d.%d or higher; kernel is %d.%d",
+ BPF_MAJOR_VERSION, BPF_MINOR_VERSION,
+ bv.bv_major, bv.bv_minor);
+ /* don't give up, just be inefficient */
+ p->md.use_bpf = 0;
+ }
+ } else
+ p->fcode = *fp;
+
+ /*XXX this goes in tcpdump*/
+ if (p->md.use_bpf)
+ fprintf(stderr, "tcpdump: Using kernel BPF filter\n");
+ else
+ fprintf(stderr, "tcpdump: Filtering in user process\n");
+ return (0);
+}
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