The Tcpdump Group git mirrors - libpcap/blob - pcap-nit.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 #ifndef lint
  22 static const char rcsid[] =
  23     "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.41 2001-12-10 07:14:18 guy Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <sys/types.h>
  31 #include <sys/time.h>
  32 #include <sys/timeb.h>
  33 #include <sys/file.h>
  34 #include <sys/ioctl.h>
  35 #include <sys/socket.h>
  36
  37 #include <net/if.h>
  38 #include <net/nit.h>
  39
  40 #include <netinet/in.h>
  41 #include <netinet/in_systm.h>
  42 #include <netinet/ip.h>
  43 #include <netinet/if_ether.h>
  44 #include <netinet/ip_var.h>
  45 #include <netinet/udp.h>
  46 #include <netinet/udp_var.h>
  47 #include <netinet/tcp.h>
  48 #include <netinet/tcpip.h>
  49
  50 #include <ctype.h>
  51 #include <errno.h>
  52 #include <stdio.h>
  53
  54 #include "pcap-int.h"
  55
  56 #ifdef HAVE_OS_PROTO_H
  57 #include "os-proto.h"
  58 #endif
  59
  60 /*
  61  * The chunk size for NIT.  This is the amount of buffering
  62  * done for read calls.
  63  */
  64 #define CHUNKSIZE (2*1024)
  65
  66 /*
  67  * The total buffer space used by NIT.
  68  */
  69 #define BUFSPACE (4*CHUNKSIZE)
  70
  71 /* Forwards */
  72 static int nit_setflags(int, int, int, char *);
  73
  74 int
  75 pcap_stats(pcap_t *p, struct pcap_stat *ps)
  76 {
  77
  78         /*
  79          * "ps_recv" counts packets handed to the filter, not packets
  80          * that passed the filter.  As filtering is done in userland,
  81          * this does not include packets dropped because we ran out
  82          * of buffer space.
  83          *
  84          * "ps_drop" presumably counts packets dropped by the socket
  85          * because of flow control requirements or resource exhaustion;
  86          * it doesn't count packets dropped by the interface driver.
  87          * As filtering is done in userland, it counts packets regardless
  88          * of whether they would've passed the filter.
  89          *
  90          * These statistics don't include packets not yet read from the
  91          * kernel by libpcap or packets not yet read from libpcap by the
  92          * application.
  93          */
  94         *ps = p->md.stat;
  95         return (0);
  96 }
  97
  98 int
  99 pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 100 {
 101         register int cc, n;
 102         register struct bpf_insn *fcode = p->fcode.bf_insns;
 103         register u_char *bp, *cp, *ep;
 104         register struct nit_hdr *nh;
 105         register int caplen;
 106
 107         cc = p->cc;
 108         if (cc == 0) {
 109                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 110                 if (cc < 0) {
 111                         if (errno == EWOULDBLOCK)
 112                                 return (0);
 113                         snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 114                                 pcap_strerror(errno));
 115                         return (-1);
 116                 }
 117                 bp = p->buffer;
 118         } else
 119                 bp = p->bp;
 120
 121         /*
 122          * Loop through each packet.  The increment expression
 123          * rounds up to the next int boundary past the end of
 124          * the previous packet.
 125          */
 126         n = 0;
 127         ep = bp + cc;
 128         while (bp < ep) {
 129                 nh = (struct nit_hdr *)bp;
 130                 cp = bp + sizeof(*nh);
 131
 132                 switch (nh->nh_state) {
 133
 134                 case NIT_CATCH:
 135                         break;
 136
 137                 case NIT_NOMBUF:
 138                 case NIT_NOCLUSTER:
 139                 case NIT_NOSPACE:
 140                         p->md.stat.ps_drop = nh->nh_dropped;
 141                         continue;
 142
 143                 case NIT_SEQNO:
 144                         continue;
 145
 146                 default:
 147                         snprintf(p->errbuf, sizeof(p->errbuf),
 148                             "bad nit state %d", nh->nh_state);
 149                         return (-1);
 150                 }
 151                 ++p->md.stat.ps_recv;
 152                 bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
 153                     sizeof(int) - 1) & ~(sizeof(int) - 1));
 154
 155                 caplen = nh->nh_wirelen;
 156                 if (caplen > p->snapshot)
 157                         caplen = p->snapshot;
 158                 if (bpf_filter(fcode, cp, nh->nh_wirelen, caplen)) {
 159                         struct pcap_pkthdr h;
 160                         h.ts = nh->nh_timestamp;
 161                         h.len = nh->nh_wirelen;
 162                         h.caplen = caplen;
 163                         (*callback)(user, &h, cp);
 164                         if (++n >= cnt && cnt >= 0) {
 165                                 p->cc = ep - bp;
 166                                 p->bp = bp;
 167                                 return (n);
 168                         }
 169                 }
 170         }
 171         p->cc = 0;
 172         return (n);
 173 }
 174
 175 static int
 176 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
 177 {
 178         struct nit_ioc nioc;
 179
 180         memset(&nioc, 0, sizeof(nioc));
 181         nioc.nioc_bufspace = BUFSPACE;
 182         nioc.nioc_chunksize = CHUNKSIZE;
 183         nioc.nioc_typetomatch = NT_ALLTYPES;
 184         nioc.nioc_snaplen = p->snapshot;
 185         nioc.nioc_bufalign = sizeof(int);
 186         nioc.nioc_bufoffset = 0;
 187
 188         if (to_ms != 0) {
 189                 nioc.nioc_flags |= NF_TIMEOUT;
 190                 nioc.nioc_timeout.tv_sec = to_ms / 1000;
 191                 nioc.nioc_timeout.tv_usec = (to_ms * 1000) % 1000000;
 192         }
 193         if (promisc)
 194                 nioc.nioc_flags |= NF_PROMISC;
 195
 196         if (ioctl(fd, SIOCSNIT, &nioc) < 0) {
 197                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNIT: %s",
 198                     pcap_strerror(errno));
 199                 return (-1);
 200         }
 201         return (0);
 202 }
 203
 204 pcap_t *
 205 pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
 206 {
 207         int fd;
 208         struct sockaddr_nit snit;
 209         register pcap_t *p;
 210
 211         p = (pcap_t *)malloc(sizeof(*p));
 212         if (p == NULL) {
 213                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 214                 return (NULL);
 215         }
 216
 217         if (snaplen < 96)
 218                 /*
 219                  * NIT requires a snapshot length of at least 96.
 220                  */
 221                 snaplen = 96;
 222
 223         memset(p, 0, sizeof(*p));
 224         p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
 225         if (fd < 0) {
 226                 snprintf(ebuf, PCAP_ERRBUF_SIZE,
 227                     "socket: %s", pcap_strerror(errno));
 228                 goto bad;
 229         }
 230         snit.snit_family = AF_NIT;
 231         (void)strncpy(snit.snit_ifname, device, NITIFSIZ);
 232
 233         if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
 234                 snprintf(ebuf, PCAP_ERRBUF_SIZE,
 235                     "bind: %s: %s", snit.snit_ifname, pcap_strerror(errno));
 236                 goto bad;
 237         }
 238         p->snapshot = snaplen;
 239         nit_setflags(p->fd, promisc, to_ms, ebuf);
 240
 241         /*
 242          * NIT supports only ethernets.
 243          */
 244         p->linktype = DLT_EN10MB;
 245
 246         p->bufsize = BUFSPACE;
 247         p->buffer = (u_char *)malloc(p->bufsize);
 248         if (p->buffer == NULL) {
 249                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 250                 goto bad;
 251         }
 252         return (p);
 253  bad:
 254         if (fd >= 0)
 255                 close(fd);
 256         free(p);
 257         return (NULL);
 258 }
 259
 260 int
 261 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 262 {
 263
 264         if (install_bpf_program(p, fp) < 0)
 265                 return (-1);
 266         return (0);
 267 }