JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 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 | |
| 75 | typedef enum { OTHER = -1, NFLOG, NFQUEUE } nftype_t; |
| 76 | |
| 77 | /* |
| 78 | * Private data for capturing on Linux netfilter sockets. |
| 79 | */ |
| 80 | struct pcap_netfilter { |
| 81 | u_int packets_read; /* count of packets read with recvfrom() */ |
| 82 | }; |
| 83 | |
| 84 | static int nfqueue_send_verdict(const pcap_t *handle, u_int16_t group_id, u_int32_t id, u_int32_t verdict); |
| 85 | |
| 86 | static int |
| 87 | netfilter_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) |
| 88 | { |
| 89 | struct pcap_netfilter *handlep = handle->priv; |
| 90 | const unsigned char *buf; |
| 91 | int count = 0; |
| 92 | int len; |
| 93 | |
| 94 | /* ignore interrupt system call error */ |
| 95 | do { |
| 96 | len = recv(handle->fd, handle->buffer, handle->bufsize, 0); |
| 97 | if (handle->break_loop) { |
| 98 | handle->break_loop = 0; |
| 99 | return -2; |
| 100 | } |
| 101 | } while ((len == -1) && (errno == EINTR)); |
| 102 | |
| 103 | if (len < 0) { |
| 104 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s", errno, pcap_strerror(errno)); |
| 105 | return -1; |
| 106 | } |
| 107 | |
| 108 | buf = handle->buffer; |
| 109 | while (len >= NLMSG_SPACE(0)) { |
| 110 | const struct nlmsghdr *nlh = (const struct nlmsghdr *) buf; |
| 111 | u_int32_t msg_len; |
| 112 | nftype_t type = OTHER; |
| 113 | |
| 114 | if (nlh->nlmsg_len < sizeof(struct nlmsghdr) || len < nlh->nlmsg_len) { |
| 115 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Message truncated: (got: %d) (nlmsg_len: %u)", len, nlh->nlmsg_len); |
| 116 | return -1; |
| 117 | } |
| 118 | |
| 119 | if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_ULOG && |
| 120 | NFNL_MSG_TYPE(nlh->nlmsg_type) == NFULNL_MSG_PACKET) |
| 121 | type = NFLOG; |
| 122 | |
| 123 | if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_QUEUE && |
| 124 | NFNL_MSG_TYPE(nlh->nlmsg_type) == NFQNL_MSG_PACKET) |
| 125 | type = NFQUEUE; |
| 126 | |
| 127 | if (type != OTHER) { |
| 128 | const unsigned char *payload = NULL; |
| 129 | struct pcap_pkthdr pkth; |
| 130 | |
| 131 | const struct nfgenmsg *nfg; |
| 132 | int id = 0; |
| 133 | |
| 134 | if (handle->linktype != DLT_NFLOG) { |
| 135 | const struct nfattr *payload_attr = NULL; |
| 136 | |
| 137 | if (nlh->nlmsg_len < HDR_LENGTH) { |
| 138 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Malformed message: (nlmsg_len: %u)", nlh->nlmsg_len); |
| 139 | return -1; |
| 140 | } |
| 141 | |
| 142 | nfg = NLMSG_DATA(nlh); |
| 143 | if (nlh->nlmsg_len > HDR_LENGTH) { |
| 144 | struct nfattr *attr = NFM_NFA(nfg); |
| 145 | int attr_len = nlh->nlmsg_len - NLMSG_ALIGN(HDR_LENGTH); |
| 146 | |
| 147 | while (NFA_OK(attr, attr_len)) { |
| 148 | if (type == NFQUEUE) { |
| 149 | switch (NFA_TYPE(attr)) { |
| 150 | case NFQA_PACKET_HDR: |
| 151 | { |
| 152 | const struct nfqnl_msg_packet_hdr *pkt_hdr = (const struct nfqnl_msg_packet_hdr *) NFA_DATA(attr); |
| 153 | |
| 154 | id = ntohl(pkt_hdr->packet_id); |
| 155 | break; |
| 156 | } |
| 157 | case NFQA_PAYLOAD: |
| 158 | payload_attr = attr; |
| 159 | break; |
| 160 | } |
| 161 | |
| 162 | } else if (type == NFLOG) { |
| 163 | switch (NFA_TYPE(attr)) { |
| 164 | case NFULA_PAYLOAD: |
| 165 | payload_attr = attr; |
| 166 | break; |
| 167 | } |
| 168 | } |
| 169 | attr = NFA_NEXT(attr, attr_len); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | if (payload_attr) { |
| 174 | payload = NFA_DATA(payload_attr); |
| 175 | pkth.len = pkth.caplen = NFA_PAYLOAD(payload_attr); |
| 176 | } |
| 177 | |
| 178 | } else { |
| 179 | payload = NLMSG_DATA(nlh); |
| 180 | pkth.caplen = pkth.len = nlh->nlmsg_len-NLMSG_ALIGN(sizeof(struct nlmsghdr)); |
| 181 | } |
| 182 | |
| 183 | if (payload) { |
| 184 | /* pkth.caplen = min (payload_len, handle->snapshot); */ |
| 185 | |
| 186 | gettimeofday(&pkth.ts, NULL); |
| 187 | if (handle->fcode.bf_insns == NULL || |
| 188 | bpf_filter(handle->fcode.bf_insns, payload, pkth.len, pkth.caplen)) |
| 189 | { |
| 190 | handlep->packets_read++; |
| 191 | callback(user, &pkth, payload); |
| 192 | count++; |
| 193 | } |
| 194 | } |
| 195 | |
| 196 | if (type == NFQUEUE) { |
| 197 | /* XXX, possible responses: NF_DROP, NF_ACCEPT, NF_STOLEN, NF_QUEUE, NF_REPEAT, NF_STOP */ |
| 198 | nfqueue_send_verdict(handle, ntohs(nfg->res_id), id, NF_ACCEPT); |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | msg_len = NLMSG_ALIGN(nlh->nlmsg_len); |
| 203 | if (msg_len > len) |
| 204 | msg_len = len; |
| 205 | |
| 206 | len -= msg_len; |
| 207 | buf += msg_len; |
| 208 | } |
| 209 | return count; |
| 210 | } |
| 211 | |
| 212 | static int |
| 213 | netfilter_set_datalink(pcap_t *handle, int dlt) |
| 214 | { |
| 215 | handle->linktype = dlt; |
| 216 | return 0; |
| 217 | } |
| 218 | |
| 219 | static int |
| 220 | netfilter_stats_linux(pcap_t *handle, struct pcap_stat *stats) |
| 221 | { |
| 222 | struct pcap_netfilter *handlep = handle->priv; |
| 223 | |
| 224 | stats->ps_recv = handlep->packets_read; |
| 225 | stats->ps_drop = 0; |
| 226 | stats->ps_ifdrop = 0; |
| 227 | return 0; |
| 228 | } |
| 229 | |
| 230 | static int |
| 231 | netfilter_inject_linux(pcap_t *handle, const void *buf, size_t size) |
| 232 | { |
| 233 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on netfilter devices"); |
| 234 | return (-1); |
| 235 | } |
| 236 | |
| 237 | struct my_nfattr { |
| 238 | u_int16_t nfa_len; |
| 239 | u_int16_t nfa_type; |
| 240 | void *data; |
| 241 | }; |
| 242 | |
| 243 | static int |
| 244 | netfilter_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) |
| 245 | { |
| 246 | char buf[1024] __attribute__ ((aligned)); |
| 247 | |
| 248 | struct nlmsghdr *nlh = (struct nlmsghdr *) buf; |
| 249 | struct nfgenmsg *nfg = (struct nfgenmsg *) (buf + sizeof(struct nlmsghdr)); |
| 250 | |
| 251 | struct sockaddr_nl snl; |
| 252 | static unsigned int seq_id; |
| 253 | |
| 254 | if (!seq_id) |
| 255 | seq_id = time(NULL); |
| 256 | ++seq_id; |
| 257 | |
| 258 | nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nfgenmsg)); |
| 259 | nlh->nlmsg_type = msg_type; |
| 260 | nlh->nlmsg_flags = NLM_F_REQUEST | (ack ? NLM_F_ACK : 0); |
| 261 | nlh->nlmsg_pid = 0; /* to kernel */ |
| 262 | nlh->nlmsg_seq = seq_id; |
| 263 | |
| 264 | nfg->nfgen_family = family; |
| 265 | nfg->version = NFNETLINK_V0; |
| 266 | nfg->res_id = htons(res_id); |
| 267 | |
| 268 | if (mynfa) { |
| 269 | struct nfattr *nfa = (struct nfattr *) (buf + NLMSG_ALIGN(nlh->nlmsg_len)); |
| 270 | |
| 271 | nfa->nfa_type = mynfa->nfa_type; |
| 272 | nfa->nfa_len = NFA_LENGTH(mynfa->nfa_len); |
| 273 | memcpy(NFA_DATA(nfa), mynfa->data, mynfa->nfa_len); |
| 274 | nlh->nlmsg_len = NLMSG_ALIGN(nlh->nlmsg_len) + NFA_ALIGN(nfa->nfa_len); |
| 275 | } |
| 276 | |
| 277 | memset(&snl, 0, sizeof(snl)); |
| 278 | snl.nl_family = AF_NETLINK; |
| 279 | |
| 280 | if (sendto(handle->fd, nlh, nlh->nlmsg_len, 0, (struct sockaddr *) &snl, sizeof(snl)) == -1) |
| 281 | return -1; |
| 282 | |
| 283 | if (!ack) |
| 284 | return 0; |
| 285 | |
| 286 | /* waiting for reply loop */ |
| 287 | do { |
| 288 | socklen_t addrlen = sizeof(snl); |
| 289 | int len; |
| 290 | |
| 291 | /* ignore interrupt system call error */ |
| 292 | do { |
| 293 | len = recvfrom(handle->fd, buf, sizeof(buf), 0, (struct sockaddr *) &snl, &addrlen); |
| 294 | } while ((len == -1) && (errno == EINTR)); |
| 295 | |
| 296 | if (len <= 0) |
| 297 | return len; |
| 298 | |
| 299 | if (addrlen != sizeof(snl) || snl.nl_family != AF_NETLINK) { |
| 300 | errno = EINVAL; |
| 301 | return -1; |
| 302 | } |
| 303 | |
| 304 | nlh = (struct nlmsghdr *) buf; |
| 305 | if (snl.nl_pid != 0 || seq_id != nlh->nlmsg_seq) /* if not from kernel or wrong sequence skip */ |
| 306 | continue; |
| 307 | |
| 308 | while (len >= NLMSG_SPACE(0) && NLMSG_OK(nlh, len)) { |
| 309 | if (nlh->nlmsg_type == NLMSG_ERROR || (nlh->nlmsg_type == NLMSG_DONE && nlh->nlmsg_flags & NLM_F_MULTI)) { |
| 310 | if (nlh->nlmsg_len < NLMSG_ALIGN(sizeof(struct nlmsgerr))) { |
| 311 | errno = EBADMSG; |
| 312 | return -1; |
| 313 | } |
| 314 | errno = -(*((int *)NLMSG_DATA(nlh))); |
| 315 | return (errno == 0) ? 0 : -1; |
| 316 | } |
| 317 | nlh = NLMSG_NEXT(nlh, len); |
| 318 | } |
| 319 | } while (1); |
| 320 | |
| 321 | return -1; /* never here */ |
| 322 | } |
| 323 | |
| 324 | static int |
| 325 | nflog_send_config_msg(const pcap_t *handle, u_int8_t family, u_int16_t group_id, const struct my_nfattr *mynfa) |
| 326 | { |
| 327 | return netfilter_send_config_msg(handle, (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG, 1, family, group_id, mynfa); |
| 328 | } |
| 329 | |
| 330 | static int |
| 331 | nflog_send_config_cmd(const pcap_t *handle, u_int16_t group_id, u_int8_t cmd, u_int8_t family) |
| 332 | { |
| 333 | struct nfulnl_msg_config_cmd msg; |
| 334 | struct my_nfattr nfa; |
| 335 | |
| 336 | msg.command = cmd; |
| 337 | |
| 338 | nfa.data = &msg; |
| 339 | nfa.nfa_type = NFULA_CFG_CMD; |
| 340 | nfa.nfa_len = sizeof(msg); |
| 341 | |
| 342 | return nflog_send_config_msg(handle, family, group_id, &nfa); |
| 343 | } |
| 344 | |
| 345 | static int |
| 346 | nflog_send_config_mode(const pcap_t *handle, u_int16_t group_id, u_int8_t copy_mode, u_int32_t copy_range) |
| 347 | { |
| 348 | struct nfulnl_msg_config_mode msg; |
| 349 | struct my_nfattr nfa; |
| 350 | |
| 351 | msg.copy_range = htonl(copy_range); |
| 352 | msg.copy_mode = copy_mode; |
| 353 | |
| 354 | nfa.data = &msg; |
| 355 | nfa.nfa_type = NFULA_CFG_MODE; |
| 356 | nfa.nfa_len = sizeof(msg); |
| 357 | |
| 358 | return nflog_send_config_msg(handle, AF_UNSPEC, group_id, &nfa); |
| 359 | } |
| 360 | |
| 361 | static int |
| 362 | nfqueue_send_verdict(const pcap_t *handle, u_int16_t group_id, u_int32_t id, u_int32_t verdict) |
| 363 | { |
| 364 | struct nfqnl_msg_verdict_hdr msg; |
| 365 | struct my_nfattr nfa; |
| 366 | |
| 367 | msg.id = htonl(id); |
| 368 | msg.verdict = htonl(verdict); |
| 369 | |
| 370 | nfa.data = &msg; |
| 371 | nfa.nfa_type = NFQA_VERDICT_HDR; |
| 372 | nfa.nfa_len = sizeof(msg); |
| 373 | |
| 374 | return netfilter_send_config_msg(handle, (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_VERDICT, 0, AF_UNSPEC, group_id, &nfa); |
| 375 | } |
| 376 | |
| 377 | static int |
| 378 | nfqueue_send_config_msg(const pcap_t *handle, u_int8_t family, u_int16_t group_id, const struct my_nfattr *mynfa) |
| 379 | { |
| 380 | return netfilter_send_config_msg(handle, (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG, 1, family, group_id, mynfa); |
| 381 | } |
| 382 | |
| 383 | static int |
| 384 | nfqueue_send_config_cmd(const pcap_t *handle, u_int16_t group_id, u_int8_t cmd, u_int16_t pf) |
| 385 | { |
| 386 | struct nfqnl_msg_config_cmd msg; |
| 387 | struct my_nfattr nfa; |
| 388 | |
| 389 | msg.command = cmd; |
| 390 | msg.pf = htons(pf); |
| 391 | |
| 392 | nfa.data = &msg; |
| 393 | nfa.nfa_type = NFQA_CFG_CMD; |
| 394 | nfa.nfa_len = sizeof(msg); |
| 395 | |
| 396 | return nfqueue_send_config_msg(handle, AF_UNSPEC, group_id, &nfa); |
| 397 | } |
| 398 | |
| 399 | static int |
| 400 | nfqueue_send_config_mode(const pcap_t *handle, u_int16_t group_id, u_int8_t copy_mode, u_int32_t copy_range) |
| 401 | { |
| 402 | struct nfqnl_msg_config_params msg; |
| 403 | struct my_nfattr nfa; |
| 404 | |
| 405 | msg.copy_range = htonl(copy_range); |
| 406 | msg.copy_mode = copy_mode; |
| 407 | |
| 408 | nfa.data = &msg; |
| 409 | nfa.nfa_type = NFQA_CFG_PARAMS; |
| 410 | nfa.nfa_len = sizeof(msg); |
| 411 | |
| 412 | return nfqueue_send_config_msg(handle, AF_UNSPEC, group_id, &nfa); |
| 413 | } |
| 414 | |
| 415 | static int |
| 416 | netfilter_activate(pcap_t* handle) |
| 417 | { |
| 418 | const char *dev = handle->opt.source; |
| 419 | unsigned short groups[32]; |
| 420 | int group_count = 0; |
| 421 | nftype_t type = OTHER; |
| 422 | int i; |
| 423 | |
| 424 | if (strncmp(dev, NFLOG_IFACE, strlen(NFLOG_IFACE)) == 0) { |
| 425 | dev += strlen(NFLOG_IFACE); |
| 426 | type = NFLOG; |
| 427 | |
| 428 | } else if (strncmp(dev, NFQUEUE_IFACE, strlen(NFQUEUE_IFACE)) == 0) { |
| 429 | dev += strlen(NFQUEUE_IFACE); |
| 430 | type = NFQUEUE; |
| 431 | } |
| 432 | |
| 433 | if (type != OTHER && *dev == ':') { |
| 434 | dev++; |
| 435 | while (*dev) { |
| 436 | long int group_id; |
| 437 | char *end_dev; |
| 438 | |
| 439 | if (group_count == 32) { |
| 440 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, |
| 441 | "Maximum 32 netfilter groups! dev: %s", |
| 442 | handle->opt.source); |
| 443 | return PCAP_ERROR; |
| 444 | } |
| 445 | |
| 446 | group_id = strtol(dev, &end_dev, 0); |
| 447 | if (end_dev != dev) { |
| 448 | if (group_id < 0 || group_id > 65535) { |
| 449 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, |
| 450 | "Netfilter group range from 0 to 65535 (got %ld)", |
| 451 | group_id); |
| 452 | return PCAP_ERROR; |
| 453 | } |
| 454 | |
| 455 | groups[group_count++] = (unsigned short) group_id; |
| 456 | dev = end_dev; |
| 457 | } |
| 458 | if (*dev != ',') |
| 459 | break; |
| 460 | dev++; |
| 461 | } |
| 462 | } |
| 463 | |
| 464 | if (type == OTHER || *dev) { |
| 465 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, |
| 466 | "Can't get netfilter group(s) index from %s", |
| 467 | handle->opt.source); |
| 468 | return PCAP_ERROR; |
| 469 | } |
| 470 | |
| 471 | /* if no groups, add default: 0 */ |
| 472 | if (!group_count) { |
| 473 | groups[0] = 0; |
| 474 | group_count = 1; |
| 475 | } |
| 476 | |
| 477 | /* Initialize some components of the pcap structure. */ |
| 478 | handle->bufsize = 128 + handle->snapshot; |
| 479 | handle->offset = 0; |
| 480 | handle->read_op = netfilter_read_linux; |
| 481 | handle->inject_op = netfilter_inject_linux; |
| 482 | handle->setfilter_op = install_bpf_program; /* no kernel filtering */ |
| 483 | handle->setdirection_op = NULL; |
| 484 | handle->set_datalink_op = netfilter_set_datalink; |
| 485 | handle->getnonblock_op = pcap_getnonblock_fd; |
| 486 | handle->setnonblock_op = pcap_setnonblock_fd; |
| 487 | handle->stats_op = netfilter_stats_linux; |
| 488 | |
| 489 | /* Create netlink socket */ |
| 490 | handle->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); |
| 491 | if (handle->fd < 0) { |
| 492 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s", errno, pcap_strerror(errno)); |
| 493 | return PCAP_ERROR; |
| 494 | } |
| 495 | |
| 496 | if (type == NFLOG) { |
| 497 | handle->linktype = DLT_NFLOG; |
| 498 | handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); |
| 499 | if (handle->dlt_list != NULL) { |
| 500 | handle->dlt_list[0] = DLT_NFLOG; |
| 501 | handle->dlt_list[1] = DLT_IPV4; |
| 502 | handle->dlt_count = 2; |
| 503 | } |
| 504 | |
| 505 | } else |
| 506 | handle->linktype = DLT_IPV4; |
| 507 | |
| 508 | handle->buffer = malloc(handle->bufsize); |
| 509 | if (!handle->buffer) { |
| 510 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s", pcap_strerror(errno)); |
| 511 | goto close_fail; |
| 512 | } |
| 513 | |
| 514 | if (type == NFLOG) { |
| 515 | if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) { |
| 516 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_CFG_CMD_PF_UNBIND: %s", pcap_strerror(errno)); |
| 517 | goto close_fail; |
| 518 | } |
| 519 | |
| 520 | if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_BIND, AF_INET) < 0) { |
| 521 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_CFG_CMD_PF_BIND: %s", pcap_strerror(errno)); |
| 522 | goto close_fail; |
| 523 | } |
| 524 | |
| 525 | /* Bind socket to the nflog groups */ |
| 526 | for (i = 0; i < group_count; i++) { |
| 527 | if (nflog_send_config_cmd(handle, groups[i], NFULNL_CFG_CMD_BIND, AF_UNSPEC) < 0) { |
| 528 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't listen on group group index: %s", pcap_strerror(errno)); |
| 529 | goto close_fail; |
| 530 | } |
| 531 | |
| 532 | if (nflog_send_config_mode(handle, groups[i], NFULNL_COPY_PACKET, handle->snapshot) < 0) { |
| 533 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_COPY_PACKET: %s", pcap_strerror(errno)); |
| 534 | goto close_fail; |
| 535 | } |
| 536 | } |
| 537 | |
| 538 | } else { |
| 539 | if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) { |
| 540 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_CFG_CMD_PF_UNBIND: %s", pcap_strerror(errno)); |
| 541 | goto close_fail; |
| 542 | } |
| 543 | |
| 544 | if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_BIND, AF_INET) < 0) { |
| 545 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_CFG_CMD_PF_BIND: %s", pcap_strerror(errno)); |
| 546 | goto close_fail; |
| 547 | } |
| 548 | |
| 549 | /* Bind socket to the nfqueue groups */ |
| 550 | for (i = 0; i < group_count; i++) { |
| 551 | if (nfqueue_send_config_cmd(handle, groups[i], NFQNL_CFG_CMD_BIND, AF_UNSPEC) < 0) { |
| 552 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't listen on group group index: %s", pcap_strerror(errno)); |
| 553 | goto close_fail; |
| 554 | } |
| 555 | |
| 556 | if (nfqueue_send_config_mode(handle, groups[i], NFQNL_COPY_PACKET, handle->snapshot) < 0) { |
| 557 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_COPY_PACKET: %s", pcap_strerror(errno)); |
| 558 | goto close_fail; |
| 559 | } |
| 560 | } |
| 561 | } |
| 562 | |
| 563 | if (handle->opt.rfmon) { |
| 564 | /* |
| 565 | * Monitor mode doesn't apply to netfilter devices. |
| 566 | */ |
| 567 | pcap_cleanup_live_common(handle); |
| 568 | return PCAP_ERROR_RFMON_NOTSUP; |
| 569 | } |
| 570 | |
| 571 | if (handle->opt.buffer_size != 0) { |
| 572 | /* |
| 573 | * Set the socket buffer size to the specified value. |
| 574 | */ |
| 575 | if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF, &handle->opt.buffer_size, sizeof(handle->opt.buffer_size)) == -1) { |
| 576 | snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "SO_RCVBUF: %s", pcap_strerror(errno)); |
| 577 | goto close_fail; |
| 578 | } |
| 579 | } |
| 580 | |
| 581 | handle->selectable_fd = handle->fd; |
| 582 | return 0; |
| 583 | |
| 584 | close_fail: |
| 585 | pcap_cleanup_live_common(handle); |
| 586 | return PCAP_ERROR; |
| 587 | } |
| 588 | |
| 589 | pcap_t * |
| 590 | netfilter_create(const char *device, char *ebuf, int *is_ours) |
| 591 | { |
| 592 | const char *cp; |
| 593 | pcap_t *p; |
| 594 | |
| 595 | /* Does this look like an netfilter device? */ |
| 596 | cp = strrchr(device, '/'); |
| 597 | if (cp == NULL) |
| 598 | cp = device; |
| 599 | |
| 600 | /* Does it begin with NFLOG_IFACE or NFQUEUE_IFACE? */ |
| 601 | if (strncmp(cp, NFLOG_IFACE, sizeof NFLOG_IFACE - 1) == 0) |
| 602 | cp += sizeof NFLOG_IFACE - 1; |
| 603 | else if (strncmp(cp, NFQUEUE_IFACE, sizeof NFQUEUE_IFACE - 1) == 0) |
| 604 | cp += sizeof NFQUEUE_IFACE - 1; |
| 605 | else { |
| 606 | /* Nope, doesn't begin with NFLOG_IFACE nor NFQUEUE_IFACE */ |
| 607 | *is_ours = 0; |
| 608 | return NULL; |
| 609 | } |
| 610 | |
| 611 | /* |
| 612 | * Yes - is that either the end of the name, or is it followed |
| 613 | * by a colon? |
| 614 | */ |
| 615 | if (*cp != ':' && *cp != '\0') { |
| 616 | /* Nope */ |
| 617 | *is_ours = 0; |
| 618 | return NULL; |
| 619 | } |
| 620 | |
| 621 | /* OK, it's probably ours. */ |
| 622 | *is_ours = 1; |
| 623 | |
| 624 | p = pcap_create_common(device, ebuf, sizeof (struct pcap_netfilter)); |
| 625 | if (p == NULL) |
| 626 | return (NULL); |
| 627 | |
| 628 | p->activate_op = netfilter_activate; |
| 629 | return (p); |
| 630 | } |
| 631 | |
| 632 | int |
| 633 | netfilter_findalldevs(pcap_if_t **alldevsp, char *err_str) |
| 634 | { |
| 635 | int sock; |
| 636 | |
| 637 | sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); |
| 638 | if (sock < 0) { |
| 639 | /* if netlink is not supported this is not fatal */ |
| 640 | if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT) |
| 641 | return 0; |
| 642 | snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't open netlink socket %d:%s", |
| 643 | errno, pcap_strerror(errno)); |
| 644 | return -1; |
| 645 | } |
| 646 | close(sock); |
| 647 | |
| 648 | if (pcap_add_if(alldevsp, NFLOG_IFACE, 0, "Linux netfilter log (NFLOG) interface", err_str) < 0) |
| 649 | return -1; |
| 650 | if (pcap_add_if(alldevsp, NFQUEUE_IFACE, 0, "Linux netfilter queue (NFQUEUE) interface", err_str) < 0) |
| 651 | return -1; |
| 652 | return 0; |
| 653 | } |