1 /* $NetBSD: pcap-snoop.c,v 1.1.1.4 2013/12/31 16:57:20 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1993, 1994, 1995, 1996, 1997 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that: (1) source code distributions 9 * retain the above copyright notice and this paragraph in its entirety, (2) 10 * distributions including binary code include the above copyright notice and 11 * this paragraph in its entirety in the documentation or other materials 12 * provided with the distribution, and (3) all advertising materials mentioning 13 * features or use of this software display the following acknowledgement: 14 * ``This product includes software developed by the University of California, 15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 16 * the University nor the names of its contributors may be used to endorse 17 * or promote products derived from this software without specific prior 18 * written permission. 19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 22 */ 23 #ifndef lint 24 static const char rcsid[] _U_ = 25 "@(#) Header: /tcpdump/master/libpcap/pcap-snoop.c,v 1.59 2008-12-02 16:25:14 guy Exp (LBL)"; 26 #endif 27 28 #ifdef HAVE_CONFIG_H 29 #include "config.h" 30 #endif 31 32 #include <sys/param.h> 33 #include <sys/file.h> 34 #include <sys/ioctl.h> 35 #include <sys/socket.h> 36 #include <sys/time.h> 37 38 #include <net/raw.h> 39 #include <net/if.h> 40 41 #include <netinet/in.h> 42 #include <netinet/in_systm.h> 43 #include <netinet/ip.h> 44 #include <netinet/if_ether.h> 45 #include <netinet/ip_var.h> 46 #include <netinet/udp.h> 47 #include <netinet/udp_var.h> 48 #include <netinet/tcp.h> 49 #include <netinet/tcpip.h> 50 51 #include <errno.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #include "pcap-int.h" 58 59 #ifdef HAVE_OS_PROTO_H 60 #include "os-proto.h" 61 #endif 62 63 /* 64 * Private data for capturing on snoop devices. 65 */ 66 struct pcap_snoop { 67 struct pcap_stat stat; 68 }; 69 70 static int 71 pcap_read_snoop(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 72 { 73 struct pcap_snoop *psn = p->priv; 74 int cc; 75 register struct snoopheader *sh; 76 register u_int datalen; 77 register u_int caplen; 78 register u_char *cp; 79 80 again: 81 /* 82 * Has "pcap_breakloop()" been called? 83 */ 84 if (p->break_loop) { 85 /* 86 * Yes - clear the flag that indicates that it 87 * has, and return -2 to indicate that we were 88 * told to break out of the loop. 89 */ 90 p->break_loop = 0; 91 return (-2); 92 } 93 cc = read(p->fd, (char *)p->buffer, p->bufsize); 94 if (cc < 0) { 95 /* Don't choke when we get ptraced */ 96 switch (errno) { 97 98 case EINTR: 99 goto again; 100 101 case EWOULDBLOCK: 102 return (0); /* XXX */ 103 } 104 snprintf(p->errbuf, sizeof(p->errbuf), 105 "read: %s", pcap_strerror(errno)); 106 return (-1); 107 } 108 sh = (struct snoopheader *)p->buffer; 109 datalen = sh->snoop_packetlen; 110 111 /* 112 * XXX - Sigh, snoop_packetlen is a 16 bit quantity. If we 113 * got a short length, but read a full sized snoop pakcet, 114 * assume we overflowed and add back the 64K... 115 */ 116 if (cc == (p->snapshot + sizeof(struct snoopheader)) && 117 (datalen < p->snapshot)) 118 datalen += (64 * 1024); 119 120 caplen = (datalen < p->snapshot) ? datalen : p->snapshot; 121 cp = (u_char *)(sh + 1) + p->offset; /* XXX */ 122 123 /* 124 * XXX unfortunately snoop loopback isn't exactly like 125 * BSD's. The address family is encoded in the first 2 126 * bytes rather than the first 4 bytes! Luckily the last 127 * two snoop loopback bytes are zeroed. 128 */ 129 if (p->linktype == DLT_NULL && *((short *)(cp + 2)) == 0) { 130 u_int *uip = (u_int *)cp; 131 *uip >>= 16; 132 } 133 134 if (p->fcode.bf_insns == NULL || 135 bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) { 136 struct pcap_pkthdr h; 137 ++psn->stat.ps_recv; 138 h.ts.tv_sec = sh->snoop_timestamp.tv_sec; 139 h.ts.tv_usec = sh->snoop_timestamp.tv_usec; 140 h.len = datalen; 141 h.caplen = caplen; 142 (*callback)(user, &h, cp); 143 return (1); 144 } 145 return (0); 146 } 147 148 static int 149 pcap_inject_snoop(pcap_t *p, const void *buf, size_t size) 150 { 151 int ret; 152 153 /* 154 * XXX - libnet overwrites the source address with what I 155 * presume is the interface's address; is that required? 156 */ 157 ret = write(p->fd, buf, size); 158 if (ret == -1) { 159 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s", 160 pcap_strerror(errno)); 161 return (-1); 162 } 163 return (ret); 164 } 165 166 static int 167 pcap_stats_snoop(pcap_t *p, struct pcap_stat *ps) 168 { 169 struct pcap_snoop *psn = p->priv; 170 register struct rawstats *rs; 171 struct rawstats rawstats; 172 173 rs = &rawstats; 174 memset(rs, 0, sizeof(*rs)); 175 if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) { 176 snprintf(p->errbuf, sizeof(p->errbuf), 177 "SIOCRAWSTATS: %s", pcap_strerror(errno)); 178 return (-1); 179 } 180 181 /* 182 * "ifdrops" are those dropped by the network interface 183 * due to resource shortages or hardware errors. 184 * 185 * "sbdrops" are those dropped due to socket buffer limits. 186 * 187 * As filter is done in userland, "sbdrops" counts packets 188 * regardless of whether they would've passed the filter. 189 * 190 * XXX - does this count *all* Snoop or Drain sockets, 191 * rather than just this socket? If not, why does it have 192 * both Snoop and Drain statistics? 193 */ 194 psn->stat.ps_drop = 195 rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops + 196 rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops; 197 198 /* 199 * "ps_recv" counts only packets that passed the filter. 200 * As filtering is done in userland, this does not include 201 * packets dropped because we ran out of buffer space. 202 */ 203 *ps = psn->stat; 204 return (0); 205 } 206 207 /* XXX can't disable promiscuous */ 208 static int 209 pcap_activate_snoop(pcap_t *p) 210 { 211 int fd; 212 struct sockaddr_raw sr; 213 struct snoopfilter sf; 214 u_int v; 215 int ll_hdrlen; 216 int snooplen; 217 struct ifreq ifr; 218 219 fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP); 220 if (fd < 0) { 221 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snoop socket: %s", 222 pcap_strerror(errno)); 223 goto bad; 224 } 225 p->fd = fd; 226 memset(&sr, 0, sizeof(sr)); 227 sr.sr_family = AF_RAW; 228 (void)strncpy(sr.sr_ifname, p->opt.source, sizeof(sr.sr_ifname)); 229 if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) { 230 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snoop bind: %s", 231 pcap_strerror(errno)); 232 goto bad; 233 } 234 memset(&sf, 0, sizeof(sf)); 235 if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) { 236 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s", 237 pcap_strerror(errno)); 238 goto bad; 239 } 240 if (p->opt.buffer_size != 0) 241 v = p->opt.buffer_size; 242 else 243 v = 64 * 1024; /* default to 64K buffer size */ 244 (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v)); 245 /* 246 * XXX hack - map device name to link layer type 247 */ 248 if (strncmp("et", p->opt.source, 2) == 0 || /* Challenge 10 Mbit */ 249 strncmp("ec", p->opt.source, 2) == 0 || /* Indigo/Indy 10 Mbit, 250 O2 10/100 */ 251 strncmp("ef", p->opt.source, 2) == 0 || /* O200/2000 10/100 Mbit */ 252 strncmp("eg", p->opt.source, 2) == 0 || /* Octane/O2xxx/O3xxx Gigabit */ 253 strncmp("gfe", p->opt.source, 3) == 0 || /* GIO 100 Mbit */ 254 strncmp("fxp", p->opt.source, 3) == 0 || /* Challenge VME Enet */ 255 strncmp("ep", p->opt.source, 2) == 0 || /* Challenge 8x10 Mbit EPLEX */ 256 strncmp("vfe", p->opt.source, 3) == 0 || /* Challenge VME 100Mbit */ 257 strncmp("fa", p->opt.source, 2) == 0 || 258 strncmp("qaa", p->opt.source, 3) == 0 || 259 strncmp("cip", p->opt.source, 3) == 0 || 260 strncmp("el", p->opt.source, 2) == 0) { 261 p->linktype = DLT_EN10MB; 262 p->offset = RAW_HDRPAD(sizeof(struct ether_header)); 263 ll_hdrlen = sizeof(struct ether_header); 264 /* 265 * This is (presumably) a real Ethernet capture; give it a 266 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so 267 * that an application can let you choose it, in case you're 268 * capturing DOCSIS traffic that a Cisco Cable Modem 269 * Termination System is putting out onto an Ethernet (it 270 * doesn't put an Ethernet header onto the wire, it puts raw 271 * DOCSIS frames out on the wire inside the low-level 272 * Ethernet framing). 273 * 274 * XXX - are there any sorts of "fake Ethernet" that have 275 * Ethernet link-layer headers but that *shouldn't offer 276 * DLT_DOCSIS as a Cisco CMTS won't put traffic onto it 277 * or get traffic bridged onto it? "el" is for ATM LANE 278 * Ethernet devices, so that might be the case for them; 279 * the same applies for "qaa" classical IP devices. If 280 * "fa" devices are for FORE SPANS, that'd apply to them 281 * as well; what are "cip" devices - some other ATM 282 * Classical IP devices? 283 */ 284 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); 285 /* 286 * If that fails, just leave the list empty. 287 */ 288 if (p->dlt_list != NULL) { 289 p->dlt_list[0] = DLT_EN10MB; 290 p->dlt_list[1] = DLT_DOCSIS; 291 p->dlt_count = 2; 292 } 293 } else if (strncmp("ipg", p->opt.source, 3) == 0 || 294 strncmp("rns", p->opt.source, 3) == 0 || /* O2/200/2000 FDDI */ 295 strncmp("xpi", p->opt.source, 3) == 0) { 296 p->linktype = DLT_FDDI; 297 p->offset = 3; /* XXX yeah? */ 298 ll_hdrlen = 13; 299 } else if (strncmp("ppp", p->opt.source, 3) == 0) { 300 p->linktype = DLT_RAW; 301 ll_hdrlen = 0; /* DLT_RAW meaning "no PPP header, just the IP packet"? */ 302 } else if (strncmp("qfa", p->opt.source, 3) == 0) { 303 p->linktype = DLT_IP_OVER_FC; 304 ll_hdrlen = 24; 305 } else if (strncmp("pl", p->opt.source, 2) == 0) { 306 p->linktype = DLT_RAW; 307 ll_hdrlen = 0; /* Cray UNICOS/mp pseudo link */ 308 } else if (strncmp("lo", p->opt.source, 2) == 0) { 309 p->linktype = DLT_NULL; 310 ll_hdrlen = 4; 311 } else { 312 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 313 "snoop: unknown physical layer type"); 314 goto bad; 315 } 316 317 if (p->opt.rfmon) { 318 /* 319 * No monitor mode on Irix (no Wi-Fi devices on 320 * hardware supported by Irix). 321 */ 322 return (PCAP_ERROR_RFMON_NOTSUP); 323 } 324 325 #ifdef SIOCGIFMTU 326 /* 327 * XXX - IRIX appears to give you an error if you try to set the 328 * capture length to be greater than the MTU, so let's try to get 329 * the MTU first and, if that succeeds, trim the snap length 330 * to be no greater than the MTU. 331 */ 332 (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); 333 if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) { 334 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s", 335 pcap_strerror(errno)); 336 goto bad; 337 } 338 /* 339 * OK, we got it. 340 * 341 * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an 342 * "ifru_metric" member of the "ifr_ifru" union in an "ifreq" 343 * structure, others don't. 344 * 345 * I've no idea what's going on, so, if "ifr_mtu" isn't defined, 346 * we define it as "ifr_metric", as using that field appears to 347 * work on the versions that lack "ifr_mtu" (and, on those that 348 * don't lack it, "ifru_metric" and "ifru_mtu" are both "int" 349 * members of the "ifr_ifru" union, which suggests that they 350 * may be interchangeable in this case). 351 */ 352 #ifndef ifr_mtu 353 #define ifr_mtu ifr_metric 354 #endif 355 if (p->snapshot > ifr.ifr_mtu + ll_hdrlen) 356 p->snapshot = ifr.ifr_mtu + ll_hdrlen; 357 #endif 358 359 /* 360 * The argument to SIOCSNOOPLEN is the number of link-layer 361 * payload bytes to capture - it doesn't count link-layer 362 * header bytes. 363 */ 364 snooplen = p->snapshot - ll_hdrlen; 365 if (snooplen < 0) 366 snooplen = 0; 367 if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) { 368 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s", 369 pcap_strerror(errno)); 370 goto bad; 371 } 372 v = 1; 373 if (ioctl(fd, SIOCSNOOPING, &v) < 0) { 374 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s", 375 pcap_strerror(errno)); 376 goto bad; 377 } 378 379 p->bufsize = 4096; /* XXX */ 380 p->buffer = (u_char *)malloc(p->bufsize); 381 if (p->buffer == NULL) { 382 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", 383 pcap_strerror(errno)); 384 goto bad; 385 } 386 387 /* 388 * "p->fd" is a socket, so "select()" should work on it. 389 */ 390 p->selectable_fd = p->fd; 391 392 p->read_op = pcap_read_snoop; 393 p->inject_op = pcap_inject_snoop; 394 p->setfilter_op = install_bpf_program; /* no kernel filtering */ 395 p->setdirection_op = NULL; /* Not implemented. */ 396 p->set_datalink_op = NULL; /* can't change data link type */ 397 p->getnonblock_op = pcap_getnonblock_fd; 398 p->setnonblock_op = pcap_setnonblock_fd; 399 p->stats_op = pcap_stats_snoop; 400 401 return (0); 402 bad: 403 pcap_cleanup_live_common(p); 404 return (PCAP_ERROR); 405 } 406 407 pcap_t * 408 pcap_create_interface(const char *device, char *ebuf) 409 { 410 pcap_t *p; 411 412 p = pcap_create_common(device, ebuf, sizeof (struct pcap_snoop)); 413 if (p == NULL) 414 return (NULL); 415 416 p->activate_op = pcap_activate_snoop; 417 return (p); 418 } 419 420 int 421 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) 422 { 423 return (0); 424 } 425