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[] _U_ =
  23     "@(#) $Header: /tcpdump/master/libpcap/pcap-nit.c,v 1.62 2008-04-14 20:40:58 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 static int
  75 pcap_stats_nit(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 static int
  99 pcap_read_nit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 100 {
 101         register int cc, n;
 102         register u_char *bp, *cp, *ep;
 103         register struct nit_hdr *nh;
 104         register int caplen;
 105
 106         cc = p->cc;
 107         if (cc == 0) {
 108                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 109                 if (cc < 0) {
 110                         if (errno == EWOULDBLOCK)
 111                                 return (0);
 112                         snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 113                                 pcap_strerror(errno));
 114                         return (-1);
 115                 }
 116                 bp = p->buffer;
 117         } else
 118                 bp = p->bp;
 119
 120         /*
 121          * Loop through each packet.  The increment expression
 122          * rounds up to the next int boundary past the end of
 123          * the previous packet.
 124          */
 125         n = 0;
 126         ep = bp + cc;
 127         while (bp < ep) {
 128                 /*
 129                  * Has "pcap_breakloop()" been called?
 130                  * If so, return immediately - if we haven't read any
 131                  * packets, clear the flag and return -2 to indicate
 132                  * that we were told to break out of the loop, otherwise
 133                  * leave the flag set, so that the *next* call will break
 134                  * out of the loop without having read any packets, and
 135                  * return the number of packets we've processed so far.
 136                  */
 137                 if (p->break_loop) {
 138                         if (n == 0) {
 139                                 p->break_loop = 0;
 140                                 return (-2);
 141                         } else {
 142                                 p->cc = ep - bp;
 143                                 p->bp = bp;
 144                                 return (n);
 145                         }
 146                 }
 147
 148                 nh = (struct nit_hdr *)bp;
 149                 cp = bp + sizeof(*nh);
 150
 151                 switch (nh->nh_state) {
 152
 153                 case NIT_CATCH:
 154                         break;
 155
 156                 case NIT_NOMBUF:
 157                 case NIT_NOCLUSTER:
 158                 case NIT_NOSPACE:
 159                         p->md.stat.ps_drop = nh->nh_dropped;
 160                         continue;
 161
 162                 case NIT_SEQNO:
 163                         continue;
 164
 165                 default:
 166                         snprintf(p->errbuf, sizeof(p->errbuf),
 167                             "bad nit state %d", nh->nh_state);
 168                         return (-1);
 169                 }
 170                 ++p->md.stat.ps_recv;
 171                 bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
 172                     sizeof(int) - 1) & ~(sizeof(int) - 1));
 173
 174                 caplen = nh->nh_wirelen;
 175                 if (caplen > p->snapshot)
 176                         caplen = p->snapshot;
 177                 if (bpf_filter(p->fcode.bf_insns, cp, nh->nh_wirelen, caplen)) {
 178                         struct pcap_pkthdr h;
 179                         h.ts = nh->nh_timestamp;
 180                         h.len = nh->nh_wirelen;
 181                         h.caplen = caplen;
 182                         (*callback)(user, &h, cp);
 183                         if (++n >= cnt && cnt > 0) {
 184                                 p->cc = ep - bp;
 185                                 p->bp = bp;
 186                                 return (n);
 187                         }
 188                 }
 189         }
 190         p->cc = 0;
 191         return (n);
 192 }
 193
 194 static int
 195 pcap_inject_nit(pcap_t *p, const void *buf, size_t size)
 196 {
 197         struct sockaddr sa;
 198         int ret;
 199
 200         memset(&sa, 0, sizeof(sa));
 201         strncpy(sa.sa_data, device, sizeof(sa.sa_data));
 202         ret = sendto(p->fd, buf, size, 0, &sa, sizeof(sa));
 203         if (ret == -1) {
 204                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 205                     pcap_strerror(errno));
 206                 return (-1);
 207         }
 208         return (ret);
 209 }
 210
 211 static int
 212 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
 213 {
 214         struct nit_ioc nioc;
 215
 216         memset(&nioc, 0, sizeof(nioc));
 217         nioc.nioc_bufspace = BUFSPACE;
 218         nioc.nioc_chunksize = CHUNKSIZE;
 219         nioc.nioc_typetomatch = NT_ALLTYPES;
 220         nioc.nioc_snaplen = p->snapshot;
 221         nioc.nioc_bufalign = sizeof(int);
 222         nioc.nioc_bufoffset = 0;
 223
 224         if (to_ms != 0) {
 225                 nioc.nioc_flags |= NF_TIMEOUT;
 226                 nioc.nioc_timeout.tv_sec = to_ms / 1000;
 227                 nioc.nioc_timeout.tv_usec = (to_ms * 1000) % 1000000;
 228         }
 229         if (promisc)
 230                 nioc.nioc_flags |= NF_PROMISC;
 231
 232         if (ioctl(fd, SIOCSNIT, &nioc) < 0) {
 233                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNIT: %s",
 234                     pcap_strerror(errno));
 235                 return (-1);
 236         }
 237         return (0);
 238 }
 239
 240 static int
 241 pcap_activate_nit(pcap_t *p)
 242 {
 243         int fd;
 244         struct sockaddr_nit snit;
 245
 246         if (p->opt.rfmon) {
 247                 /*
 248                  * No monitor mode on SunOS 3.x or earlier (no
 249                  * Wi-Fi *devices* for the hardware that supported
 250                  * them!).
 251                  */
 252                 return (PCAP_ERROR_RFMON_NOTSUP);
 253         }
 254
 255         if (p->snapshot < 96)
 256                 /*
 257                  * NIT requires a snapshot length of at least 96.
 258                  */
 259                 p->snapshot = 96;
 260
 261         memset(p, 0, sizeof(*p));
 262         p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
 263         if (fd < 0) {
 264                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 265                     "socket: %s", pcap_strerror(errno));
 266                 goto bad;
 267         }
 268         snit.snit_family = AF_NIT;
 269         (void)strncpy(snit.snit_ifname, p->opt.source, NITIFSIZ);
 270
 271         if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
 272                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 273                     "bind: %s: %s", snit.snit_ifname, pcap_strerror(errno));
 274                 goto bad;
 275         }
 276         nit_setflags(p->fd, p->opt.promisc, p->md.timeout, p->errbuf);
 277
 278         /*
 279          * NIT supports only ethernets.
 280          */
 281         p->linktype = DLT_EN10MB;
 282
 283         p->bufsize = BUFSPACE;
 284         p->buffer = (u_char *)malloc(p->bufsize);
 285         if (p->buffer == NULL) {
 286                 strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 287                 goto bad;
 288         }
 289
 290         /*
 291          * "p->fd" is a socket, so "select()" should work on it.
 292          */
 293         p->selectable_fd = p->fd;
 294
 295         /*
 296          * This is (presumably) a real Ethernet capture; give it a
 297          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 298          * that an application can let you choose it, in case you're
 299          * capturing DOCSIS traffic that a Cisco Cable Modem
 300          * Termination System is putting out onto an Ethernet (it
 301          * doesn't put an Ethernet header onto the wire, it puts raw
 302          * DOCSIS frames out on the wire inside the low-level
 303          * Ethernet framing).
 304          */
 305         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 306         /*
 307          * If that fails, just leave the list empty.
 308          */
 309         if (p->dlt_list != NULL) {
 310                 p->dlt_list[0] = DLT_EN10MB;
 311                 p->dlt_list[1] = DLT_DOCSIS;
 312                 p->dlt_count = 2;
 313         }
 314
 315         p->read_op = pcap_read_nit;
 316         p->inject_op = pcap_inject_nit;
 317         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 318         p->setdirection_op = NULL;      /* Not implemented. */
 319         p->set_datalink_op = NULL;      /* can't change data link type */
 320         p->getnonblock_op = pcap_getnonblock_fd;
 321         p->setnonblock_op = pcap_setnonblock_fd;
 322         p->stats_op = pcap_stats_nit;
 323
 324         return (0);
 325  bad:
 326         pcap_cleanup_live_common(p);
 327         return (PCAP_ERROR);
 328 }
 329
 330 pcap_t *
 331 pcap_create(const char *device, char *ebuf)
 332 {
 333         pcap_t *p;
 334
 335         p = pcap_create_common(device, ebuf);
 336         if (p == NULL)
 337                 return (NULL);
 338
 339         p->activate_op = pcap_activate_nit;
 340         return (p);
 341 }
 342
 343 int
 344 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 345 {
 346         return (0);
 347 }