1/* 2 * Copyright (c) 2011 Jakub Zawadzki 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote 15 * products derived from this software without specific prior written 16 * permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#ifdef HAVE_CONFIG_H 32#include "config.h" 33#endif 34 35#include "pcap-int.h" 36 37#ifdef NEED_STRERROR_H 38#include "strerror.h" 39#endif 40 41#include <errno.h> 42#include <stdlib.h> 43#include <unistd.h> 44#include <string.h> 45#include <sys/socket.h> 46#include <arpa/inet.h> 47 48#include <time.h> 49#include <sys/time.h> 50#include <netinet/in.h> 51#include <linux/types.h> 52 53#include <linux/netlink.h> 54#include <linux/netfilter.h> 55#include <linux/netfilter/nfnetlink.h> 56#include <linux/netfilter/nfnetlink_log.h> 57#include <linux/netfilter/nfnetlink_queue.h> 58 59/* NOTE: if your program drops privilages after pcap_activate() it WON'T work with nfqueue. 60 * It took me quite some time to debug ;/ 61 * 62 * Sending any data to nfnetlink socket requires CAP_NET_ADMIN privilages, 63 * and in nfqueue we need to send verdict reply after recving packet. 64 * 65 * In tcpdump you can disable dropping privilages with -Z root 66 */ 67 68#include "pcap-netfilter-linux.h" 69 70#define HDR_LENGTH (NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct nfgenmsg)))) 71 72#define NFLOG_IFACE "nflog" 73#define NFQUEUE_IFACE "nfqueue" 74 75typedef enum { OTHER = -1, NFLOG, NFQUEUE } nftype_t; 76 77static int nfqueue_send_verdict(const pcap_t *handle, u_int16_t group_id, u_int32_t id, u_int32_t verdict); 78 79static int 80netfilter_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) 81{ 82 const unsigned char *buf; 83 int count = 0; 84 int len; 85 86 /* ignore interrupt system call error */ 87 do { 88 len = recv(handle->fd, handle->buffer, handle->bufsize, 0); 89 if (handle->break_loop) { 90 handle->break_loop = 0; 91 return -2; 92 } 93 } while ((len == -1) && (errno == EINTR)); 94 95 if (len < 0) { 96 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s", errno, pcap_strerror(errno)); 97 return -1; 98 } 99 100 buf = handle->buffer; 101 while (len >= NLMSG_SPACE(0)) { 102 const struct nlmsghdr *nlh = (const struct nlmsghdr *) buf; 103 u_int32_t msg_len; 104 nftype_t type = OTHER; 105 106 if (nlh->nlmsg_len < sizeof(struct nlmsghdr) || len < nlh->nlmsg_len) { 107 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Message truncated: (got: %d) (nlmsg_len: %u)", len, nlh->nlmsg_len); 108 return -1; 109 } 110 111 if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_ULOG && 112 NFNL_MSG_TYPE(nlh->nlmsg_type) == NFULNL_MSG_PACKET) 113 type = NFLOG; 114 115 if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_QUEUE && 116 NFNL_MSG_TYPE(nlh->nlmsg_type) == NFQNL_MSG_PACKET) 117 type = NFQUEUE; 118 119 if (type != OTHER) { 120 const unsigned char *payload = NULL; 121 struct pcap_pkthdr pkth; 122 123 const struct nfgenmsg *nfg; 124 int id = 0; 125 126 if (handle->linktype != DLT_NFLOG) { 127 const struct nfattr *payload_attr = NULL; 128 129 if (nlh->nlmsg_len < HDR_LENGTH) { 130 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Malformed message: (nlmsg_len: %u)", nlh->nlmsg_len); 131 return -1; 132 } 133 134 nfg = NLMSG_DATA(nlh); 135 if (nlh->nlmsg_len > HDR_LENGTH) { 136 struct nfattr *attr = NFM_NFA(nfg); 137 int attr_len = nlh->nlmsg_len - NLMSG_ALIGN(HDR_LENGTH); 138 139 while (NFA_OK(attr, attr_len)) { 140 if (type == NFQUEUE) { 141 switch (NFA_TYPE(attr)) { 142 case NFQA_PACKET_HDR: 143 { 144 const struct nfqnl_msg_packet_hdr *pkt_hdr = (const struct nfqnl_msg_packet_hdr *) NFA_DATA(attr); 145 146 id = ntohl(pkt_hdr->packet_id); 147 break; 148 } 149 case NFQA_PAYLOAD: 150 payload_attr = attr; 151 break; 152 } 153 154 } else if (type == NFLOG) { 155 switch (NFA_TYPE(attr)) { 156 case NFULA_PAYLOAD: 157 payload_attr = attr; 158 break; 159 } 160 } 161 attr = NFA_NEXT(attr, attr_len); 162 } 163 } 164 165 if (payload_attr) { 166 payload = NFA_DATA(payload_attr); 167 pkth.len = pkth.caplen = NFA_PAYLOAD(payload_attr); 168 } 169 170 } else { 171 payload = NLMSG_DATA(nlh); 172 pkth.caplen = pkth.len = nlh->nlmsg_len-NLMSG_ALIGN(sizeof(struct nlmsghdr)); 173 } 174 175 if (payload) { 176 /* pkth.caplen = min (payload_len, handle->snapshot); */ 177 178 gettimeofday(&pkth.ts, NULL); 179 if (handle->fcode.bf_insns == NULL || 180 bpf_filter(handle->fcode.bf_insns, payload, pkth.len, pkth.caplen)) 181 { 182 handle->md.packets_read++; 183 callback(user, &pkth, payload); 184 count++; 185 } 186 } 187 188 if (type == NFQUEUE) { 189 /* XXX, possible responses: NF_DROP, NF_ACCEPT, NF_STOLEN, NF_QUEUE, NF_REPEAT, NF_STOP */ 190 nfqueue_send_verdict(handle, ntohs(nfg->res_id), id, NF_ACCEPT); 191 } 192 } 193 194 msg_len = NLMSG_ALIGN(nlh->nlmsg_len); 195 if (msg_len > len) 196 msg_len = len; 197 198 len -= msg_len; 199 buf += msg_len; 200 } 201 return count; 202} 203 204static int 205netfilter_set_datalink(pcap_t *handle, int dlt) 206{ 207 handle->linktype = dlt; 208 return 0; 209} 210 211static int 212netfilter_stats_linux(pcap_t *handle, struct pcap_stat *stats) 213{ 214 stats->ps_recv = handle->md.packets_read; 215 stats->ps_drop = 0; 216 stats->ps_ifdrop = 0; 217 return 0; 218} 219 220static int 221netfilter_inject_linux(pcap_t *handle, const void *buf, size_t size) 222{ 223 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on netfilter devices"); 224 return (-1); 225} 226 227struct my_nfattr { 228 u_int16_t nfa_len; 229 u_int16_t nfa_type; 230 void *data; 231}; 232 233static int 234netfilter_send_config_msg(const pcap_t *handle, u_int16_t msg_type, int ack, u_int8_t family, u_int16_t res_id, const struct my_nfattr *mynfa) 235{ 236 char buf[1024] __attribute__ ((aligned)); 237 238 struct nlmsghdr *nlh = (struct nlmsghdr *) buf; 239 struct nfgenmsg *nfg = (struct nfgenmsg *) (buf + sizeof(struct nlmsghdr)); 240 241 struct sockaddr_nl snl; 242 static unsigned int seq_id; 243 244 if (!seq_id) 245 seq_id = time(NULL); 246 ++seq_id; 247 248 nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nfgenmsg)); 249 nlh->nlmsg_type = msg_type; 250 nlh->nlmsg_flags = NLM_F_REQUEST | (ack ? NLM_F_ACK : 0); 251 nlh->nlmsg_pid = 0; /* to kernel */ 252 nlh->nlmsg_seq = seq_id; 253 254 nfg->nfgen_family = family; 255 nfg->version = NFNETLINK_V0; 256 nfg->res_id = htons(res_id); 257 258 if (mynfa) { 259 struct nfattr *nfa = (struct nfattr *) (buf + NLMSG_ALIGN(nlh->nlmsg_len)); 260 261 nfa->nfa_type = mynfa->nfa_type; 262 nfa->nfa_len = NFA_LENGTH(mynfa->nfa_len); 263 memcpy(NFA_DATA(nfa), mynfa->data, mynfa->nfa_len); 264 nlh->nlmsg_len = NLMSG_ALIGN(nlh->nlmsg_len) + NFA_ALIGN(nfa->nfa_len); 265 } 266 267 memset(&snl, 0, sizeof(snl)); 268 snl.nl_family = AF_NETLINK; 269 270 if (sendto(handle->fd, nlh, nlh->nlmsg_len, 0, (struct sockaddr *) &snl, sizeof(snl)) == -1) 271 return -1; 272 273 if (!ack) 274 return 0; 275 276 /* waiting for reply loop */ 277 do { 278 socklen_t addrlen = sizeof(snl); 279 int len; 280 281 /* ignore interrupt system call error */ 282 do { 283 len = recvfrom(handle->fd, buf, sizeof(buf), 0, (struct sockaddr *) &snl, &addrlen); 284 } while ((len == -1) && (errno == EINTR)); 285 286 if (len <= 0) 287 return len; 288 289 if (addrlen != sizeof(snl) || snl.nl_family != AF_NETLINK) { 290 errno = EINVAL; 291 return -1; 292 } 293 294 nlh = (struct nlmsghdr *) buf; 295 if (snl.nl_pid != 0 || seq_id != nlh->nlmsg_seq) /* if not from kernel or wrong sequence skip */ 296 continue; 297 298 while (len >= NLMSG_SPACE(0) && NLMSG_OK(nlh, len)) { 299 if (nlh->nlmsg_type == NLMSG_ERROR || (nlh->nlmsg_type == NLMSG_DONE && nlh->nlmsg_flags & NLM_F_MULTI)) { 300 if (nlh->nlmsg_len < NLMSG_ALIGN(sizeof(struct nlmsgerr))) { 301 errno = EBADMSG; 302 return -1; 303 } 304 errno = -(*((int *)NLMSG_DATA(nlh))); 305 return (errno == 0) ? 0 : -1; 306 } 307 nlh = NLMSG_NEXT(nlh, len); 308 } 309 } while (1); 310 311 return -1; /* never here */ 312} 313 314static int 315nflog_send_config_msg(const pcap_t *handle, u_int8_t family, u_int16_t group_id, const struct my_nfattr *mynfa) 316{ 317 return netfilter_send_config_msg(handle, (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG, 1, family, group_id, mynfa); 318} 319 320static int 321nflog_send_config_cmd(const pcap_t *handle, u_int16_t group_id, u_int8_t cmd, u_int8_t family) 322{ 323 struct nfulnl_msg_config_cmd msg; 324 struct my_nfattr nfa; 325 326 msg.command = cmd; 327 328 nfa.data = &msg; 329 nfa.nfa_type = NFULA_CFG_CMD; 330 nfa.nfa_len = sizeof(msg); 331 332 return nflog_send_config_msg(handle, family, group_id, &nfa); 333} 334 335static int 336nflog_send_config_mode(const pcap_t *handle, u_int16_t group_id, u_int8_t copy_mode, u_int32_t copy_range) 337{ 338 struct nfulnl_msg_config_mode msg; 339 struct my_nfattr nfa; 340 341 msg.copy_range = htonl(copy_range); 342 msg.copy_mode = copy_mode; 343 344 nfa.data = &msg; 345 nfa.nfa_type = NFULA_CFG_MODE; 346 nfa.nfa_len = sizeof(msg); 347 348 return nflog_send_config_msg(handle, AF_UNSPEC, group_id, &nfa); 349} 350 351static int 352nfqueue_send_verdict(const pcap_t *handle, u_int16_t group_id, u_int32_t id, u_int32_t verdict) 353{ 354 struct nfqnl_msg_verdict_hdr msg; 355 struct my_nfattr nfa; 356 357 msg.id = htonl(id); 358 msg.verdict = htonl(verdict); 359 360 nfa.data = &msg; 361 nfa.nfa_type = NFQA_VERDICT_HDR; 362 nfa.nfa_len = sizeof(msg); 363 364 return netfilter_send_config_msg(handle, (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_VERDICT, 0, AF_UNSPEC, group_id, &nfa); 365} 366 367static int 368nfqueue_send_config_msg(const pcap_t *handle, u_int8_t family, u_int16_t group_id, const struct my_nfattr *mynfa) 369{ 370 return netfilter_send_config_msg(handle, (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG, 1, family, group_id, mynfa); 371} 372 373static int 374nfqueue_send_config_cmd(const pcap_t *handle, u_int16_t group_id, u_int8_t cmd, u_int16_t pf) 375{ 376 struct nfqnl_msg_config_cmd msg; 377 struct my_nfattr nfa; 378 379 msg.command = cmd; 380 msg.pf = htons(pf); 381 382 nfa.data = &msg; 383 nfa.nfa_type = NFQA_CFG_CMD; 384 nfa.nfa_len = sizeof(msg); 385 386 return nfqueue_send_config_msg(handle, AF_UNSPEC, group_id, &nfa); 387} 388 389static int 390nfqueue_send_config_mode(const pcap_t *handle, u_int16_t group_id, u_int8_t copy_mode, u_int32_t copy_range) 391{ 392 struct nfqnl_msg_config_params msg; 393 struct my_nfattr nfa; 394 395 msg.copy_range = htonl(copy_range); 396 msg.copy_mode = copy_mode; 397 398 nfa.data = &msg; 399 nfa.nfa_type = NFQA_CFG_PARAMS; 400 nfa.nfa_len = sizeof(msg); 401 402 return nfqueue_send_config_msg(handle, AF_UNSPEC, group_id, &nfa); 403} 404 405static int 406netfilter_activate(pcap_t* handle) 407{ 408 const char *dev = handle->opt.source; 409 unsigned short groups[32]; 410 int group_count = 0; 411 nftype_t type = OTHER; 412 int i; 413 414 if (strncmp(dev, NFLOG_IFACE, strlen(NFLOG_IFACE)) == 0) { 415 dev += strlen(NFLOG_IFACE); 416 type = NFLOG; 417 418 } else if (strncmp(dev, NFQUEUE_IFACE, strlen(NFQUEUE_IFACE)) == 0) { 419 dev += strlen(NFQUEUE_IFACE); 420 type = NFQUEUE; 421 } 422 423 if (type != OTHER && *dev == ':') { 424 dev++; 425 while (*dev) { 426 long int group_id; 427 char *end_dev; 428 429 if (group_count == 32) { 430 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 431 "Maximum 32 netfilter groups! dev: %s", 432 handle->opt.source); 433 return PCAP_ERROR; 434 } 435 436 group_id = strtol(dev, &end_dev, 0); 437 if (end_dev != dev) { 438 if (group_id < 0 || group_id > 65535) { 439 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 440 "Netfilter group range from 0 to 65535 (got %ld)", 441 group_id); 442 return PCAP_ERROR; 443 } 444 445 groups[group_count++] = (unsigned short) group_id; 446 dev = end_dev; 447 } 448 if (*dev != ',') 449 break; 450 dev++; 451 } 452 } 453 454 if (type == OTHER || *dev) { 455 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 456 "Can't get netfilter group(s) index from %s", 457 handle->opt.source); 458 return PCAP_ERROR; 459 } 460 461 /* if no groups, add default: 0 */ 462 if (!group_count) { 463 groups[0] = 0; 464 group_count = 1; 465 } 466 467 /* Initialize some components of the pcap structure. */ 468 handle->bufsize = 128 + handle->snapshot; 469 handle->offset = 0; 470 handle->read_op = netfilter_read_linux; 471 handle->inject_op = netfilter_inject_linux; 472 handle->setfilter_op = install_bpf_program; /* no kernel filtering */ 473 handle->setdirection_op = NULL; 474 handle->set_datalink_op = NULL; 475 handle->set_datalink_op = netfilter_set_datalink; 476 handle->getnonblock_op = pcap_getnonblock_fd; 477 handle->setnonblock_op = pcap_setnonblock_fd; 478 handle->stats_op = netfilter_stats_linux; 479 480 /* Create netlink socket */ 481 handle->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); 482 if (handle->fd < 0) { 483 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s", errno, pcap_strerror(errno)); 484 return PCAP_ERROR; 485 } 486 487 if (type == NFLOG) { 488 handle->linktype = DLT_NFLOG; 489 handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); 490 if (handle->dlt_list != NULL) { 491 handle->dlt_list[0] = DLT_NFLOG; 492 handle->dlt_list[1] = DLT_IPV4; 493 handle->dlt_count = 2; 494 } 495 496 } else 497 handle->linktype = DLT_IPV4; 498 499 handle->buffer = malloc(handle->bufsize); 500 if (!handle->buffer) { 501 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s", pcap_strerror(errno)); 502 goto close_fail; 503 } 504 505 if (type == NFLOG) { 506 if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) { 507 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_CFG_CMD_PF_UNBIND: %s", pcap_strerror(errno)); 508 goto close_fail; 509 } 510 511 if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_BIND, AF_INET) < 0) { 512 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_CFG_CMD_PF_BIND: %s", pcap_strerror(errno)); 513 goto close_fail; 514 } 515 516 /* Bind socket to the nflog groups */ 517 for (i = 0; i < group_count; i++) { 518 if (nflog_send_config_cmd(handle, groups[i], NFULNL_CFG_CMD_BIND, AF_UNSPEC) < 0) { 519 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't listen on group group index: %s", pcap_strerror(errno)); 520 goto close_fail; 521 } 522 523 if (nflog_send_config_mode(handle, groups[i], NFULNL_COPY_PACKET, handle->snapshot) < 0) { 524 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_COPY_PACKET: %s", pcap_strerror(errno)); 525 goto close_fail; 526 } 527 } 528 529 } else { 530 if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) { 531 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_CFG_CMD_PF_UNBIND: %s", pcap_strerror(errno)); 532 goto close_fail; 533 } 534 535 if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_BIND, AF_INET) < 0) { 536 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_CFG_CMD_PF_BIND: %s", pcap_strerror(errno)); 537 goto close_fail; 538 } 539 540 /* Bind socket to the nfqueue groups */ 541 for (i = 0; i < group_count; i++) { 542 if (nfqueue_send_config_cmd(handle, groups[i], NFQNL_CFG_CMD_BIND, AF_UNSPEC) < 0) { 543 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't listen on group group index: %s", pcap_strerror(errno)); 544 goto close_fail; 545 } 546 547 if (nfqueue_send_config_mode(handle, groups[i], NFQNL_COPY_PACKET, handle->snapshot) < 0) { 548 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_COPY_PACKET: %s", pcap_strerror(errno)); 549 goto close_fail; 550 } 551 } 552 } 553 554 if (handle->opt.rfmon) { 555 /* 556 * Monitor mode doesn't apply to netfilter devices. 557 */ 558 pcap_cleanup_live_common(handle); 559 return PCAP_ERROR_RFMON_NOTSUP; 560 } 561 562 if (handle->opt.buffer_size != 0) { 563 /* 564 * Set the socket buffer size to the specified value. 565 */ 566 if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF, &handle->opt.buffer_size, sizeof(handle->opt.buffer_size)) == -1) { 567 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "SO_RCVBUF: %s", pcap_strerror(errno)); 568 goto close_fail; 569 } 570 } 571 572 handle->selectable_fd = handle->fd; 573 return 0; 574 575close_fail: 576 pcap_cleanup_live_common(handle); 577 return PCAP_ERROR; 578} 579 580pcap_t * 581netfilter_create(const char *device, char *ebuf, int *is_ours) 582{ 583 const char *cp; 584 pcap_t *p; 585 586 /* Does this look like an netfilter device? */ 587 cp = strrchr(device, '/'); 588 if (cp == NULL) 589 cp = device; 590 591 /* Does it begin with NFLOG_IFACE or NFQUEUE_IFACE? */ 592 if (strncmp(cp, NFLOG_IFACE, sizeof NFLOG_IFACE - 1) == 0) 593 cp += sizeof NFLOG_IFACE - 1; 594 else if (strncmp(cp, NFQUEUE_IFACE, sizeof NFQUEUE_IFACE - 1) == 0) 595 cp += sizeof NFQUEUE_IFACE - 1; 596 else { 597 /* Nope, doesn't begin with NFLOG_IFACE nor NFQUEUE_IFACE */ 598 *is_ours = 0; 599 return NULL; 600 } 601 602 /* 603 * Yes - is that either the end of the name, or is it followed 604 * by a colon? 605 */ 606 if (*cp != ':' && *cp != '\0') { 607 /* Nope */ 608 *is_ours = 0; 609 return NULL; 610 } 611 612 /* OK, it's probably ours. */ 613 *is_ours = 1; 614 615 p = pcap_create_common(device, ebuf); 616 if (p == NULL) 617 return (NULL); 618 619 p->activate_op = netfilter_activate; 620 return (p); 621} 622 623int 624netfilter_findalldevs(pcap_if_t **alldevsp, char *err_str) 625{ 626 pcap_if_t *found_dev = *alldevsp; 627 int sock; 628 629 sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); 630 if (sock < 0) { 631 /* if netlink is not supported this is not fatal */ 632 if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT) 633 return 0; 634 snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't open netlink socket %d:%s", 635 errno, pcap_strerror(errno)); 636 return -1; 637 } 638 close(sock); 639 640 if (pcap_add_if(&found_dev, NFLOG_IFACE, 0, "Linux netfilter log (NFLOG) interface", err_str) < 0) 641 return -1; 642 if (pcap_add_if(&found_dev, NFQUEUE_IFACE, 0, "Linux netfilter queue (NFQUEUE) interface", err_str) < 0) 643 return -1; 644 return 0; 645} 646