isisd/isis_pfpacket.c

   1 /*
   2  * IS-IS Rout(e)ing protocol - isis_pfpacket.c
   3  *
   4  * Copyright (C) 2001,2002    Sampo Saaristo
   5  *                            Tampere University of Technology
   6  *                            Institute of Communications Engineering
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public Licenseas published by the Free
  10  * Software Foundation; either version 2 of the License, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16  * more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; see the file COPYING; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <zebra.h>
  24 #if ISIS_METHOD == ISIS_METHOD_PFPACKET
  25 #include <net/ethernet.h> /* the L2 protocols */
  26 #include <netpacket/packet.h>
  27
  28 #include <linux/filter.h>
  29
  30 #include "log.h"
  31 #include "network.h"
  32 #include "stream.h"
  33 #include "if.h"
  34
  35 #include "isisd/dict.h"
  36 #include "isisd/isis_constants.h"
  37 #include "isisd/isis_common.h"
  38 #include "isisd/isis_circuit.h"
  39 #include "isisd/isis_flags.h"
  40 #include "isisd/isisd.h"
  41 #include "isisd/isis_constants.h"
  42 #include "isisd/isis_circuit.h"
  43 #include "isisd/isis_network.h"
  44
  45 #include "privs.h"
  46
  47 /* tcpdump -i eth0 'isis' -dd */
  48 static struct sock_filter isisfilter[] = {
  49         /* NB: we're in SOCK_DGRAM, so src/dst mac + length are stripped
  50          * off!
  51          * (OTOH it's a bit more lower-layer agnostic and might work
  52          * over GRE?) */
  53         /*      { 0x28, 0, 0, 0x0000000c - 14 }, */
  54         /*      { 0x25, 5, 0, 0x000005dc }, */
  55         {0x28, 0, 0, 0x0000000e - 14}, {0x15, 0, 3, 0x0000fefe},
  56         {0x30, 0, 0, 0x00000011 - 14}, {0x15, 0, 1, 0x00000083},
  57         {0x6, 0, 0, 0x00040000},       {0x6, 0, 0, 0x00000000},
  58 };
  59
  60 static struct sock_fprog bpf = {
  61         .len = array_size(isisfilter),
  62         .filter = isisfilter,
  63 };
  64
  65 /*
  66  * Table 9 - Architectural constants for use with ISO 8802 subnetworks
  67  * ISO 10589 - 8.4.8
  68  */
  69
  70 uint8_t ALL_L1_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x14};
  71 uint8_t ALL_L2_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x15};
  72 uint8_t ALL_ISS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x05};
  73 uint8_t ALL_ESS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x04};
  74
  75 static uint8_t discard_buff[8192];
  76 static uint8_t sock_buff[8192];
  77
  78 /*
  79  * if level is 0 we are joining p2p multicast
  80  * FIXME: and the p2p multicast being ???
  81  */
  82 static int isis_multicast_join(int fd, int registerto, int if_num)
  83 {
  84         struct packet_mreq mreq;
  85
  86         memset(&mreq, 0, sizeof(mreq));
  87         mreq.mr_ifindex = if_num;
  88         if (registerto) {
  89                 mreq.mr_type = PACKET_MR_MULTICAST;
  90                 mreq.mr_alen = ETH_ALEN;
  91                 if (registerto == 1)
  92                         memcpy(&mreq.mr_address, ALL_L1_ISS, ETH_ALEN);
  93                 else if (registerto == 2)
  94                         memcpy(&mreq.mr_address, ALL_L2_ISS, ETH_ALEN);
  95                 else if (registerto == 3)
  96                         memcpy(&mreq.mr_address, ALL_ISS, ETH_ALEN);
  97                 else
  98                         memcpy(&mreq.mr_address, ALL_ESS, ETH_ALEN);
  99
 100         } else {
 101                 mreq.mr_type = PACKET_MR_ALLMULTI;
 102         }
 103 #ifdef EXTREME_DEBUG
 104         zlog_debug(
 105                 "isis_multicast_join(): fd=%d, reg_to=%d, if_num=%d, "
 106                 "address = %02x:%02x:%02x:%02x:%02x:%02x",
 107                 fd, registerto, if_num, mreq.mr_address[0], mreq.mr_address[1],
 108                 mreq.mr_address[2], mreq.mr_address[3], mreq.mr_address[4],
 109                 mreq.mr_address[5]);
 110 #endif /* EXTREME_DEBUG */
 111         if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq,
 112                        sizeof(struct packet_mreq))) {
 113                 zlog_warn("isis_multicast_join(): setsockopt(): %s",
 114                           safe_strerror(errno));
 115                 return ISIS_WARNING;
 116         }
 117
 118         return ISIS_OK;
 119 }
 120
 121 static int open_packet_socket(struct isis_circuit *circuit)
 122 {
 123         struct sockaddr_ll s_addr;
 124         int fd, retval = ISIS_OK;
 125
 126         fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL));
 127         if (fd < 0) {
 128                 zlog_warn("open_packet_socket(): socket() failed %s",
 129                           safe_strerror(errno));
 130                 return ISIS_WARNING;
 131         }
 132
 133         if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf))) {
 134                 zlog_warn("open_packet_socket(): SO_ATTACH_FILTER failed: %s",
 135                           safe_strerror(errno));
 136         }
 137
 138         /*
 139          * Bind to the physical interface
 140          */
 141         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 142         s_addr.sll_family = AF_PACKET;
 143         s_addr.sll_protocol = htons(ETH_P_ALL);
 144         s_addr.sll_ifindex = circuit->interface->ifindex;
 145
 146         if (bind(fd, (struct sockaddr *)(&s_addr), sizeof(struct sockaddr_ll))
 147             < 0) {
 148                 zlog_warn("open_packet_socket(): bind() failed: %s",
 149                           safe_strerror(errno));
 150                 close(fd);
 151                 return ISIS_WARNING;
 152         }
 153
 154         circuit->fd = fd;
 155
 156         if (if_is_broadcast(circuit->interface)) {
 157                 /*
 158                  * Join to multicast groups
 159                  * according to
 160                  * 8.4.2 - Broadcast subnetwork IIH PDUs
 161                  * FIXME: is there a case only one will fail??
 162                  */
 163                 /* joining ALL_L1_ISS */
 164                 retval |= isis_multicast_join(circuit->fd, 1,
 165                                               circuit->interface->ifindex);
 166                 /* joining ALL_L2_ISS */
 167                 retval |= isis_multicast_join(circuit->fd, 2,
 168                                               circuit->interface->ifindex);
 169                 /* joining ALL_ISS (used in RFC 5309 p2p-over-lan as well) */
 170                 retval |= isis_multicast_join(circuit->fd, 3,
 171                                               circuit->interface->ifindex);
 172         } else {
 173                 retval = isis_multicast_join(circuit->fd, 0,
 174                                              circuit->interface->ifindex);
 175         }
 176
 177         return retval;
 178 }
 179
 180 /*
 181  * Create the socket and set the tx/rx funcs
 182  */
 183 int isis_sock_init(struct isis_circuit *circuit)
 184 {
 185         int retval = ISIS_OK;
 186
 187         if (isisd_privs.change(ZPRIVS_RAISE))
 188                 zlog_err("%s: could not raise privs, %s", __func__,
 189                          safe_strerror(errno));
 190
 191         retval = open_packet_socket(circuit);
 192
 193         if (retval != ISIS_OK) {
 194                 zlog_warn("%s: could not initialize the socket", __func__);
 195                 goto end;
 196         }
 197
 198         /* Assign Rx and Tx callbacks are based on real if type */
 199         if (if_is_broadcast(circuit->interface)) {
 200                 circuit->tx = isis_send_pdu_bcast;
 201                 circuit->rx = isis_recv_pdu_bcast;
 202         } else if (if_is_pointopoint(circuit->interface)) {
 203                 circuit->tx = isis_send_pdu_p2p;
 204                 circuit->rx = isis_recv_pdu_p2p;
 205         } else {
 206                 zlog_warn("isis_sock_init(): unknown circuit type");
 207                 retval = ISIS_WARNING;
 208                 goto end;
 209         }
 210
 211 end:
 212         if (isisd_privs.change(ZPRIVS_LOWER))
 213                 zlog_err("%s: could not lower privs, %s", __func__,
 214                          safe_strerror(errno));
 215
 216         return retval;
 217 }
 218
 219 static inline int llc_check(uint8_t *llc)
 220 {
 221         if (*llc != ISO_SAP || *(llc + 1) != ISO_SAP || *(llc + 2) != 3)
 222                 return 0;
 223
 224         return 1;
 225 }
 226
 227 int isis_recv_pdu_bcast(struct isis_circuit *circuit, uint8_t *ssnpa)
 228 {
 229         int bytesread, addr_len;
 230         struct sockaddr_ll s_addr;
 231         uint8_t llc[LLC_LEN];
 232
 233         addr_len = sizeof(s_addr);
 234
 235         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 236
 237         bytesread =
 238                 recvfrom(circuit->fd, (void *)&llc, LLC_LEN, MSG_PEEK,
 239                          (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
 240
 241         if ((bytesread < 0)
 242             || (s_addr.sll_ifindex != (int)circuit->interface->ifindex)) {
 243                 if (bytesread < 0) {
 244                         zlog_warn(
 245                                 "isis_recv_packet_bcast(): ifname %s, fd %d, "
 246                                 "bytesread %d, recvfrom(): %s",
 247                                 circuit->interface->name, circuit->fd,
 248                                 bytesread, safe_strerror(errno));
 249                 }
 250                 if (s_addr.sll_ifindex != (int)circuit->interface->ifindex) {
 251                         zlog_warn(
 252                                 "packet is received on multiple interfaces: "
 253                                 "socket interface %d, circuit interface %d, "
 254                                 "packet type %u",
 255                                 s_addr.sll_ifindex, circuit->interface->ifindex,
 256                                 s_addr.sll_pkttype);
 257                 }
 258
 259                 /* get rid of the packet */
 260                 bytesread = recvfrom(circuit->fd, discard_buff,
 261                                      sizeof(discard_buff), MSG_DONTWAIT,
 262                                      (struct sockaddr *)&s_addr,
 263                                      (socklen_t *)&addr_len);
 264
 265                 if (bytesread < 0)
 266                         zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 267
 268                 return ISIS_WARNING;
 269         }
 270         /*
 271          * Filtering by llc field, discard packets sent by this host (other
 272          * circuit)
 273          */
 274         if (!llc_check(llc) || s_addr.sll_pkttype == PACKET_OUTGOING) {
 275                 /*  Read the packet into discard buff */
 276                 bytesread = recvfrom(circuit->fd, discard_buff,
 277                                      sizeof(discard_buff), MSG_DONTWAIT,
 278                                      (struct sockaddr *)&s_addr,
 279                                      (socklen_t *)&addr_len);
 280                 if (bytesread < 0)
 281                         zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 282                 return ISIS_WARNING;
 283         }
 284
 285         /* on lan we have to read to the static buff first */
 286         bytesread = recvfrom(circuit->fd, sock_buff, sizeof(sock_buff),
 287                              MSG_DONTWAIT, (struct sockaddr *)&s_addr,
 288                              (socklen_t *)&addr_len);
 289         if (bytesread < 0) {
 290                 zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 291                 return ISIS_WARNING;
 292         }
 293
 294         /* then we lose the LLC */
 295         stream_write(circuit->rcv_stream, sock_buff + LLC_LEN,
 296                      bytesread - LLC_LEN);
 297
 298         memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
 299
 300         return ISIS_OK;
 301 }
 302
 303 int isis_recv_pdu_p2p(struct isis_circuit *circuit, uint8_t *ssnpa)
 304 {
 305         int bytesread, addr_len;
 306         struct sockaddr_ll s_addr;
 307
 308         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 309         addr_len = sizeof(s_addr);
 310
 311         /* we can read directly to the stream */
 312         (void)stream_recvfrom(
 313                 circuit->rcv_stream, circuit->fd, circuit->interface->mtu, 0,
 314                 (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
 315
 316         if (s_addr.sll_pkttype == PACKET_OUTGOING) {
 317                 /*  Read the packet into discard buff */
 318                 bytesread = recvfrom(circuit->fd, discard_buff,
 319                                      sizeof(discard_buff), MSG_DONTWAIT,
 320                                      (struct sockaddr *)&s_addr,
 321                                      (socklen_t *)&addr_len);
 322                 if (bytesread < 0)
 323                         zlog_warn("isis_recv_pdu_p2p(): recvfrom() failed");
 324                 return ISIS_WARNING;
 325         }
 326
 327         /* If we don't have protocol type 0x00FE which is
 328          * ISO over GRE we exit with pain :)
 329          */
 330         if (ntohs(s_addr.sll_protocol) != 0x00FE) {
 331                 zlog_warn("isis_recv_pdu_p2p(): protocol mismatch(): %X",
 332                           ntohs(s_addr.sll_protocol));
 333                 return ISIS_WARNING;
 334         }
 335
 336         memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
 337
 338         return ISIS_OK;
 339 }
 340
 341 int isis_send_pdu_bcast(struct isis_circuit *circuit, int level)
 342 {
 343         struct msghdr msg;
 344         struct iovec iov[2];
 345
 346         /* we need to do the LLC in here because of P2P circuits, which will
 347          * not need it
 348          */
 349         struct sockaddr_ll sa;
 350
 351         stream_set_getp(circuit->snd_stream, 0);
 352         memset(&sa, 0, sizeof(struct sockaddr_ll));
 353         sa.sll_family = AF_PACKET;
 354
 355         size_t frame_size = stream_get_endp(circuit->snd_stream) + LLC_LEN;
 356         sa.sll_protocol = htons(isis_ethertype(frame_size));
 357         sa.sll_ifindex = circuit->interface->ifindex;
 358         sa.sll_halen = ETH_ALEN;
 359         /* RFC5309 section 4.1 recommends ALL_ISS */
 360         if (circuit->circ_type == CIRCUIT_T_P2P)
 361                 memcpy(&sa.sll_addr, ALL_ISS, ETH_ALEN);
 362         else if (level == 1)
 363                 memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
 364         else
 365                 memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
 366
 367         /* on a broadcast circuit */
 368         /* first we put the LLC in */
 369         sock_buff[0] = 0xFE;
 370         sock_buff[1] = 0xFE;
 371         sock_buff[2] = 0x03;
 372
 373         memset(&msg, 0, sizeof(msg));
 374         msg.msg_name = &sa;
 375         msg.msg_namelen = sizeof(struct sockaddr_ll);
 376         msg.msg_iov = iov;
 377         msg.msg_iovlen = 2;
 378         iov[0].iov_base = sock_buff;
 379         iov[0].iov_len = LLC_LEN;
 380         iov[1].iov_base = circuit->snd_stream->data;
 381         iov[1].iov_len = stream_get_endp(circuit->snd_stream);
 382
 383         if (sendmsg(circuit->fd, &msg, 0) < 0) {
 384                 zlog_warn("IS-IS pfpacket: could not transmit packet on %s: %s",
 385                           circuit->interface->name, safe_strerror(errno));
 386                 if (ERRNO_IO_RETRY(errno))
 387                         return ISIS_WARNING;
 388                 return ISIS_ERROR;
 389         }
 390         return ISIS_OK;
 391 }
 392
 393 int isis_send_pdu_p2p(struct isis_circuit *circuit, int level)
 394 {
 395         struct sockaddr_ll sa;
 396         ssize_t rv;
 397
 398         stream_set_getp(circuit->snd_stream, 0);
 399         memset(&sa, 0, sizeof(struct sockaddr_ll));
 400         sa.sll_family = AF_PACKET;
 401         sa.sll_ifindex = circuit->interface->ifindex;
 402         sa.sll_halen = ETH_ALEN;
 403         if (level == 1)
 404                 memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
 405         else
 406                 memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
 407
 408
 409         /* lets try correcting the protocol */
 410         sa.sll_protocol = htons(0x00FE);
 411         rv = sendto(circuit->fd, circuit->snd_stream->data,
 412                     stream_get_endp(circuit->snd_stream), 0,
 413                     (struct sockaddr *)&sa, sizeof(struct sockaddr_ll));
 414         if (rv < 0) {
 415                 zlog_warn("IS-IS pfpacket: could not transmit packet on %s: %s",
 416                           circuit->interface->name, safe_strerror(errno));
 417                 if (ERRNO_IO_RETRY(errno))
 418                         return ISIS_WARNING;
 419                 return ISIS_ERROR;
 420         }
 421         return ISIS_OK;
 422 }
 423
 424 #endif /* ISIS_METHOD == ISIS_METHOD_PFPACKET */