The Tcpdump Group git mirrors - libpcap/blob - pcap-snit.c

   1 /*
   2  * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * Modifications made to accommodate the new SunOS4.0 NIT facility by
  22  * Micky Liu, micky@cunixc.cc.columbia.edu, Columbia University in May, 1989.
  23  * This module now handles the STREAMS based NIT.
  24  */
  25
  26 #ifndef lint
  27 static const char rcsid[] =
  28     "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.56 2001-12-10 07:14:20 guy Exp $ (LBL)";
  29 #endif
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34
  35 #include <sys/types.h>
  36 #include <sys/time.h>
  37 #include <sys/timeb.h>
  38 #include <sys/dir.h>
  39 #include <sys/fcntlcom.h>
  40 #include <sys/file.h>
  41 #include <sys/ioctl.h>
  42 #include <sys/socket.h>
  43 #include <sys/stropts.h>
  44
  45 #include <net/if.h>
  46 #include <net/nit.h>
  47 #include <net/nit_if.h>
  48 #include <net/nit_pf.h>
  49 #include <net/nit_buf.h>
  50
  51 #include <netinet/in.h>
  52 #include <netinet/in_systm.h>
  53 #include <netinet/ip.h>
  54 #include <netinet/if_ether.h>
  55 #include <netinet/ip_var.h>
  56 #include <netinet/udp.h>
  57 #include <netinet/udp_var.h>
  58 #include <netinet/tcp.h>
  59 #include <netinet/tcpip.h>
  60
  61 #include <ctype.h>
  62 #include <errno.h>
  63 #include <stdio.h>
  64 #include <string.h>
  65 #include <unistd.h>
  66
  67 #include "pcap-int.h"
  68
  69 #ifdef HAVE_OS_PROTO_H
  70 #include "os-proto.h"
  71 #endif
  72
  73 /*
  74  * The chunk size for NIT.  This is the amount of buffering
  75  * done for read calls.
  76  */
  77 #define CHUNKSIZE (2*1024)
  78
  79 /*
  80  * The total buffer space used by NIT.
  81  */
  82 #define BUFSPACE (4*CHUNKSIZE)
  83
  84 /* Forwards */
  85 static int nit_setflags(int, int, int, char *);
  86
  87 int
  88 pcap_stats(pcap_t *p, struct pcap_stat *ps)
  89 {
  90
  91         /*
  92          * "ps_recv" counts packets handed to the filter, not packets
  93          * that passed the filter.  As filtering is done in userland,
  94          * this does not include packets dropped because we ran out
  95          * of buffer space.
  96          *
  97          * "ps_drop" counts packets dropped inside the "/dev/nit"
  98          * device because of flow control requirements or resource
  99          * exhaustion; it doesn't count packets dropped by the
 100          * interface driver, or packets dropped upstream.  As filtering
 101          * is done in userland, it counts packets regardless of whether
 102          * they would've passed the filter.
 103          *
 104          * These statistics don't include packets not yet read from the
 105          * kernel by libpcap or packets not yet read from libpcap by the
 106          * application.
 107          */
 108         *ps = p->md.stat;
 109         return (0);
 110 }
 111
 112 int
 113 pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 114 {
 115         register int cc, n;
 116         register struct bpf_insn *fcode = p->fcode.bf_insns;
 117         register u_char *bp, *cp, *ep;
 118         register struct nit_bufhdr *hdrp;
 119         register struct nit_iftime *ntp;
 120         register struct nit_iflen *nlp;
 121         register struct nit_ifdrops *ndp;
 122         register int caplen;
 123
 124         cc = p->cc;
 125         if (cc == 0) {
 126                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 127                 if (cc < 0) {
 128                         if (errno == EWOULDBLOCK)
 129                                 return (0);
 130                         snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 131                                 pcap_strerror(errno));
 132                         return (-1);
 133                 }
 134                 bp = p->buffer;
 135         } else
 136                 bp = p->bp;
 137
 138         /*
 139          * loop through each snapshot in the chunk
 140          */
 141         n = 0;
 142         ep = bp + cc;
 143         while (bp < ep) {
 144                 ++p->md.stat.ps_recv;
 145                 cp = bp;
 146
 147                 /* get past NIT buffer  */
 148                 hdrp = (struct nit_bufhdr *)cp;
 149                 cp += sizeof(*hdrp);
 150
 151                 /* get past NIT timer   */
 152                 ntp = (struct nit_iftime *)cp;
 153                 cp += sizeof(*ntp);
 154
 155                 ndp = (struct nit_ifdrops *)cp;
 156                 p->md.stat.ps_drop = ndp->nh_drops;
 157                 cp += sizeof *ndp;
 158
 159                 /* get past packet len  */
 160                 nlp = (struct nit_iflen *)cp;
 161                 cp += sizeof(*nlp);
 162
 163                 /* next snapshot        */
 164                 bp += hdrp->nhb_totlen;
 165
 166                 caplen = nlp->nh_pktlen;
 167                 if (caplen > p->snapshot)
 168                         caplen = p->snapshot;
 169
 170                 if (bpf_filter(fcode, cp, nlp->nh_pktlen, caplen)) {
 171                         struct pcap_pkthdr h;
 172                         h.ts = ntp->nh_timestamp;
 173                         h.len = nlp->nh_pktlen;
 174                         h.caplen = caplen;
 175                         (*callback)(user, &h, cp);
 176                         if (++n >= cnt && cnt >= 0) {
 177                                 p->cc = ep - bp;
 178                                 p->bp = bp;
 179                                 return (n);
 180                         }
 181                 }
 182         }
 183         p->cc = 0;
 184         return (n);
 185 }
 186
 187 static int
 188 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
 189 {
 190         bpf_u_int32 flags;
 191         struct strioctl si;
 192         struct timeval timeout;
 193
 194         si.ic_timout = INFTIM;
 195         if (to_ms != 0) {
 196                 timeout.tv_sec = to_ms / 1000;
 197                 timeout.tv_usec = (to_ms * 1000) % 1000000;
 198                 si.ic_cmd = NIOCSTIME;
 199                 si.ic_len = sizeof(timeout);
 200                 si.ic_dp = (char *)&timeout;
 201                 if (ioctl(fd, I_STR, (char *)&si) < 0) {
 202                         snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
 203                             pcap_strerror(errno));
 204                         return (-1);
 205                 }
 206         }
 207         flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
 208         if (promisc)
 209                 flags |= NI_PROMISC;
 210         si.ic_cmd = NIOCSFLAGS;
 211         si.ic_len = sizeof(flags);
 212         si.ic_dp = (char *)&flags;
 213         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 214                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
 215                     pcap_strerror(errno));
 216                 return (-1);
 217         }
 218         return (0);
 219 }
 220
 221 pcap_t *
 222 pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
 223 {
 224         struct strioctl si;             /* struct for ioctl() */
 225         struct ifreq ifr;               /* interface request struct */
 226         int chunksize = CHUNKSIZE;
 227         int fd;
 228         static char dev[] = "/dev/nit";
 229         register pcap_t *p;
 230
 231         p = (pcap_t *)malloc(sizeof(*p));
 232         if (p == NULL) {
 233                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 234                 return (NULL);
 235         }
 236
 237         if (snaplen < 96)
 238                 /*
 239                  * NIT requires a snapshot length of at least 96.
 240                  */
 241                 snaplen = 96;
 242
 243         memset(p, 0, sizeof(*p));
 244         p->fd = fd = open(dev, O_RDONLY);
 245         if (fd < 0) {
 246                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
 247                     pcap_strerror(errno));
 248                 goto bad;
 249         }
 250
 251         /* arrange to get discrete messages from the STREAM and use NIT_BUF */
 252         if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
 253                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
 254                     pcap_strerror(errno));
 255                 goto bad;
 256         }
 257         if (ioctl(fd, I_PUSH, "nbuf") < 0) {
 258                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
 259                     pcap_strerror(errno));
 260                 goto bad;
 261         }
 262         /* set the chunksize */
 263         si.ic_cmd = NIOCSCHUNK;
 264         si.ic_timout = INFTIM;
 265         si.ic_len = sizeof(chunksize);
 266         si.ic_dp = (char *)&chunksize;
 267         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 268                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
 269                     pcap_strerror(errno));
 270                 goto bad;
 271         }
 272
 273         /* request the interface */
 274         strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 275         ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = ' ';
 276         si.ic_cmd = NIOCBIND;
 277         si.ic_len = sizeof(ifr);
 278         si.ic_dp = (char *)&ifr;
 279         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 280                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
 281                         ifr.ifr_name, pcap_strerror(errno));
 282                 goto bad;
 283         }
 284
 285         /* set the snapshot length */
 286         si.ic_cmd = NIOCSSNAP;
 287         si.ic_len = sizeof(snaplen);
 288         si.ic_dp = (char *)&snaplen;
 289         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 290                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
 291                     pcap_strerror(errno));
 292                 goto bad;
 293         }
 294         p->snapshot = snaplen;
 295         if (nit_setflags(p->fd, promisc, to_ms, ebuf) < 0)
 296                 goto bad;
 297
 298         (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
 299         /*
 300          * NIT supports only ethernets.
 301          */
 302         p->linktype = DLT_EN10MB;
 303
 304         p->bufsize = BUFSPACE;
 305         p->buffer = (u_char *)malloc(p->bufsize);
 306         if (p->buffer == NULL) {
 307                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 308                 goto bad;
 309         }
 310         return (p);
 311  bad:
 312         if (fd >= 0)
 313                 close(fd);
 314         free(p);
 315         return (NULL);
 316 }
 317
 318 int
 319 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 320 {
 321
 322         if (install_bpf_program(p, fp) < 0)
 323                 return (-1);
 324         return (0);
 325 }