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 1.40 2001-07-29 01:22:41 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.
  81          *
  82          * "ps_drop" presumably counts packets dropped by the socket
  83          * because of flow control requirements or resource exhaustion;
  84          * it doesn't count packets dropped by the interface driver.
  85          * As filtering is done in userland, it counts packets regardless
  86          * of whether they would've passed the filter.
  87          */
  88         *ps = p->md.stat;
  89         return (0);
  90 }
  91
  92 int
  93 pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
  94 {
  95         register int cc, n;
  96         register struct bpf_insn *fcode = p->fcode.bf_insns;
  97         register u_char *bp, *cp, *ep;
  98         register struct nit_hdr *nh;
  99         register int caplen;
 100
 101         cc = p->cc;
 102         if (cc == 0) {
 103                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 104                 if (cc < 0) {
 105                         if (errno == EWOULDBLOCK)
 106                                 return (0);
 107                         snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 108                                 pcap_strerror(errno));
 109                         return (-1);
 110                 }
 111                 bp = p->buffer;
 112         } else
 113                 bp = p->bp;
 114
 115         /*
 116          * Loop through each packet.  The increment expression
 117          * rounds up to the next int boundary past the end of
 118          * the previous packet.
 119          */
 120         n = 0;
 121         ep = bp + cc;
 122         while (bp < ep) {
 123                 nh = (struct nit_hdr *)bp;
 124                 cp = bp + sizeof(*nh);
 125
 126                 switch (nh->nh_state) {
 127
 128                 case NIT_CATCH:
 129                         break;
 130
 131                 case NIT_NOMBUF:
 132                 case NIT_NOCLUSTER:
 133                 case NIT_NOSPACE:
 134                         p->md.stat.ps_drop = nh->nh_dropped;
 135                         continue;
 136
 137                 case NIT_SEQNO:
 138                         continue;
 139
 140                 default:
 141                         snprintf(p->errbuf, sizeof(p->errbuf),
 142                             "bad nit state %d", nh->nh_state);
 143                         return (-1);
 144                 }
 145                 ++p->md.stat.ps_recv;
 146                 bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
 147                     sizeof(int) - 1) & ~(sizeof(int) - 1));
 148
 149                 caplen = nh->nh_wirelen;
 150                 if (caplen > p->snapshot)
 151                         caplen = p->snapshot;
 152                 if (bpf_filter(fcode, cp, nh->nh_wirelen, caplen)) {
 153                         struct pcap_pkthdr h;
 154                         h.ts = nh->nh_timestamp;
 155                         h.len = nh->nh_wirelen;
 156                         h.caplen = caplen;
 157                         (*callback)(user, &h, cp);
 158                         if (++n >= cnt && cnt >= 0) {
 159                                 p->cc = ep - bp;
 160                                 p->bp = bp;
 161                                 return (n);
 162                         }
 163                 }
 164         }
 165         p->cc = 0;
 166         return (n);
 167 }
 168
 169 static int
 170 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
 171 {
 172         struct nit_ioc nioc;
 173
 174         memset(&nioc, 0, sizeof(nioc));
 175         nioc.nioc_bufspace = BUFSPACE;
 176         nioc.nioc_chunksize = CHUNKSIZE;
 177         nioc.nioc_typetomatch = NT_ALLTYPES;
 178         nioc.nioc_snaplen = p->snapshot;
 179         nioc.nioc_bufalign = sizeof(int);
 180         nioc.nioc_bufoffset = 0;
 181
 182         if (to_ms != 0) {
 183                 nioc.nioc_flags |= NF_TIMEOUT;
 184                 nioc.nioc_timeout.tv_sec = to_ms / 1000;
 185                 nioc.nioc_timeout.tv_usec = (to_ms * 1000) % 1000000;
 186         }
 187         if (promisc)
 188                 nioc.nioc_flags |= NF_PROMISC;
 189
 190         if (ioctl(fd, SIOCSNIT, &nioc) < 0) {
 191                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNIT: %s",
 192                     pcap_strerror(errno));
 193                 return (-1);
 194         }
 195         return (0);
 196 }
 197
 198 pcap_t *
 199 pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
 200 {
 201         int fd;
 202         struct sockaddr_nit snit;
 203         register pcap_t *p;
 204
 205         p = (pcap_t *)malloc(sizeof(*p));
 206         if (p == NULL) {
 207                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 208                 return (NULL);
 209         }
 210
 211         if (snaplen < 96)
 212                 /*
 213                  * NIT requires a snapshot length of at least 96.
 214                  */
 215                 snaplen = 96;
 216
 217         memset(p, 0, sizeof(*p));
 218         p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
 219         if (fd < 0) {
 220                 snprintf(ebuf, PCAP_ERRBUF_SIZE,
 221                     "socket: %s", pcap_strerror(errno));
 222                 goto bad;
 223         }
 224         snit.snit_family = AF_NIT;
 225         (void)strncpy(snit.snit_ifname, device, NITIFSIZ);
 226
 227         if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
 228                 snprintf(ebuf, PCAP_ERRBUF_SIZE,
 229                     "bind: %s: %s", snit.snit_ifname, pcap_strerror(errno));
 230                 goto bad;
 231         }
 232         p->snapshot = snaplen;
 233         nit_setflags(p->fd, promisc, to_ms, ebuf);
 234
 235         /*
 236          * NIT supports only ethernets.
 237          */
 238         p->linktype = DLT_EN10MB;
 239
 240         p->bufsize = BUFSPACE;
 241         p->buffer = (u_char *)malloc(p->bufsize);
 242         if (p->buffer == NULL) {
 243                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 244                 goto bad;
 245         }
 246         return (p);
 247  bad:
 248         if (fd >= 0)
 249                 close(fd);
 250         free(p);
 251         return (NULL);
 252 }
 253
 254 int
 255 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 256 {
 257
 258         if (install_bpf_program(p, fp) < 0)
 259                 return (-1);
 260         return (0);
 261 }