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 #include "lib_errors.h"
  35 #include "vrf.h"
  36
  37 #include "isisd/isis_constants.h"
  38 #include "isisd/isis_common.h"
  39 #include "isisd/isis_circuit.h"
  40 #include "isisd/isis_flags.h"
  41 #include "isisd/isisd.h"
  42 #include "isisd/isis_constants.h"
  43 #include "isisd/isis_circuit.h"
  44 #include "isisd/isis_network.h"
  45
  46 #include "privs.h"
  47
  48 /* tcpdump -i eth0 'isis' -dd */
  49 static const struct sock_filter isisfilter[] = {
  50         /* NB: we're in SOCK_DGRAM, so src/dst mac + length are stripped
  51          * off!
  52          * (OTOH it's a bit more lower-layer agnostic and might work
  53          * over GRE?) */
  54         /*      { 0x28, 0, 0, 0x0000000c - 14 }, */
  55         /*      { 0x25, 5, 0, 0x000005dc }, */
  56         {0x28, 0, 0, 0x0000000e - 14}, {0x15, 0, 3, 0x0000fefe},
  57         {0x30, 0, 0, 0x00000011 - 14}, {0x15, 0, 1, 0x00000083},
  58         {0x6, 0, 0, 0x00040000},       {0x6, 0, 0, 0x00000000},
  59 };
  60
  61 static const struct sock_fprog bpf = {
  62         .len = array_size(isisfilter),
  63         .filter = (struct sock_filter *)isisfilter,
  64 };
  65
  66 /*
  67  * Table 9 - Architectural constants for use with ISO 8802 subnetworks
  68  * ISO 10589 - 8.4.8
  69  */
  70
  71 static const uint8_t ALL_L1_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x14};
  72 static const uint8_t ALL_L2_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x15};
  73 static const uint8_t ALL_ISS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x05};
  74 static const uint8_t ALL_ESS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x04};
  75
  76 static uint8_t discard_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, address = %02x:%02x:%02x:%02x:%02x:%02x",
 106                 fd, registerto, if_num, mreq.mr_address[0], mreq.mr_address[1],
 107                 mreq.mr_address[2], mreq.mr_address[3], mreq.mr_address[4],
 108                 mreq.mr_address[5]);
 109 #endif /* EXTREME_DEBUG */
 110         if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq,
 111                        sizeof(struct packet_mreq))) {
 112                 zlog_warn("isis_multicast_join(): setsockopt(): %s",
 113                           safe_strerror(errno));
 114                 return ISIS_WARNING;
 115         }
 116
 117         return ISIS_OK;
 118 }
 119
 120 static int open_packet_socket(struct isis_circuit *circuit)
 121 {
 122         struct sockaddr_ll s_addr;
 123         int fd, retval = ISIS_OK;
 124         struct vrf *vrf = NULL;
 125
 126         vrf = vrf_lookup_by_id(circuit->interface->vrf_id);
 127
 128         if (vrf == NULL) {
 129                 zlog_warn("open_packet_socket(): failed to find vrf node");
 130                 return ISIS_WARNING;
 131         }
 132
 133         fd = vrf_socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL),
 134                         circuit->interface->vrf_id, vrf->name);
 135
 136         if (fd < 0) {
 137                 zlog_warn("open_packet_socket(): socket() failed %s",
 138                           safe_strerror(errno));
 139                 return ISIS_WARNING;
 140         }
 141
 142         if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf))) {
 143                 zlog_warn("open_packet_socket(): SO_ATTACH_FILTER failed: %s",
 144                           safe_strerror(errno));
 145         }
 146
 147         /*
 148          * Bind to the physical interface
 149          */
 150         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 151         s_addr.sll_family = AF_PACKET;
 152         s_addr.sll_protocol = htons(ETH_P_ALL);
 153         s_addr.sll_ifindex = circuit->interface->ifindex;
 154
 155         if (bind(fd, (struct sockaddr *)(&s_addr), sizeof(struct sockaddr_ll))
 156             < 0) {
 157                 zlog_warn("open_packet_socket(): bind() failed: %s",
 158                           safe_strerror(errno));
 159                 close(fd);
 160                 return ISIS_WARNING;
 161         }
 162
 163         circuit->fd = fd;
 164
 165         if (if_is_broadcast(circuit->interface)) {
 166                 /*
 167                  * Join to multicast groups
 168                  * according to
 169                  * 8.4.2 - Broadcast subnetwork IIH PDUs
 170                  * FIXME: is there a case only one will fail??
 171                  */
 172                 /* joining ALL_L1_ISS */
 173                 retval |= isis_multicast_join(circuit->fd, 1,
 174                                               circuit->interface->ifindex);
 175                 /* joining ALL_L2_ISS */
 176                 retval |= isis_multicast_join(circuit->fd, 2,
 177                                               circuit->interface->ifindex);
 178                 /* joining ALL_ISS (used in RFC 5309 p2p-over-lan as well) */
 179                 retval |= isis_multicast_join(circuit->fd, 3,
 180                                               circuit->interface->ifindex);
 181         } else {
 182                 retval = isis_multicast_join(circuit->fd, 0,
 183                                              circuit->interface->ifindex);
 184         }
 185
 186         return retval;
 187 }
 188
 189 /*
 190  * Create the socket and set the tx/rx funcs
 191  */
 192 int isis_sock_init(struct isis_circuit *circuit)
 193 {
 194         int retval = ISIS_OK;
 195
 196         frr_with_privs(&isisd_privs) {
 197
 198                 retval = open_packet_socket(circuit);
 199
 200                 if (retval != ISIS_OK) {
 201                         zlog_warn("%s: could not initialize the socket",
 202                                   __func__);
 203                         break;
 204                 }
 205
 206         /* Assign Rx and Tx callbacks are based on real if type */
 207                 if (if_is_broadcast(circuit->interface)) {
 208                         circuit->tx = isis_send_pdu_bcast;
 209                         circuit->rx = isis_recv_pdu_bcast;
 210                 } else if (if_is_pointopoint(circuit->interface)) {
 211                         circuit->tx = isis_send_pdu_p2p;
 212                         circuit->rx = isis_recv_pdu_p2p;
 213                 } else {
 214                         zlog_warn("isis_sock_init(): unknown circuit type");
 215                         retval = ISIS_WARNING;
 216                         break;
 217                 }
 218         }
 219
 220         return retval;
 221 }
 222
 223 static inline int llc_check(uint8_t *llc)
 224 {
 225         if (*llc != ISO_SAP || *(llc + 1) != ISO_SAP || *(llc + 2) != 3)
 226                 return 0;
 227
 228         return 1;
 229 }
 230
 231 int isis_recv_pdu_bcast(struct isis_circuit *circuit, uint8_t *ssnpa)
 232 {
 233         int bytesread, addr_len;
 234         struct sockaddr_ll s_addr;
 235         uint8_t llc[LLC_LEN];
 236
 237         addr_len = sizeof(s_addr);
 238
 239         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 240
 241         bytesread =
 242                 recvfrom(circuit->fd, (void *)&llc, LLC_LEN, MSG_PEEK,
 243                          (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
 244
 245         if ((bytesread < 0)
 246             || (s_addr.sll_ifindex != (int)circuit->interface->ifindex)) {
 247                 if (bytesread < 0) {
 248                         zlog_warn(
 249                                 "isis_recv_packet_bcast(): ifname %s, fd %d, bytesread %d, recvfrom(): %s",
 250                                 circuit->interface->name, circuit->fd,
 251                                 bytesread, safe_strerror(errno));
 252                 }
 253                 if (s_addr.sll_ifindex != (int)circuit->interface->ifindex) {
 254                         zlog_warn(
 255                                 "packet is received on multiple interfaces: socket interface %d, circuit interface %d, packet type %u",
 256                                 s_addr.sll_ifindex, circuit->interface->ifindex,
 257                                 s_addr.sll_pkttype);
 258                 }
 259
 260                 /* get rid of the packet */
 261                 bytesread = recvfrom(circuit->fd, discard_buff,
 262                                      sizeof(discard_buff), MSG_DONTWAIT,
 263                                      (struct sockaddr *)&s_addr,
 264                                      (socklen_t *)&addr_len);
 265
 266                 if (bytesread < 0)
 267                         zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 268
 269                 return ISIS_WARNING;
 270         }
 271         /*
 272          * Filtering by llc field, discard packets sent by this host (other
 273          * circuit)
 274          */
 275         if (!llc_check(llc) || s_addr.sll_pkttype == PACKET_OUTGOING) {
 276                 /*  Read the packet into discard buff */
 277                 bytesread = recvfrom(circuit->fd, discard_buff,
 278                                      sizeof(discard_buff), MSG_DONTWAIT,
 279                                      (struct sockaddr *)&s_addr,
 280                                      (socklen_t *)&addr_len);
 281                 if (bytesread < 0)
 282                         zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 283                 return ISIS_WARNING;
 284         }
 285
 286         /* Ensure that we have enough space for a pdu padded to fill the mtu */
 287         unsigned int max_size =
 288                 circuit->interface->mtu > circuit->interface->mtu6
 289                         ? circuit->interface->mtu
 290                         : circuit->interface->mtu6;
 291         uint8_t temp_buff[max_size];
 292         bytesread =
 293                 recvfrom(circuit->fd, temp_buff, max_size, MSG_DONTWAIT,
 294                          (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
 295         if (bytesread < 0) {
 296                 zlog_warn("%s: recvfrom() failed", __func__);
 297                 return ISIS_WARNING;
 298         }
 299         /* then we lose the LLC */
 300         stream_write(circuit->rcv_stream, temp_buff + LLC_LEN,
 301                      bytesread - LLC_LEN);
 302         memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
 303
 304         return ISIS_OK;
 305 }
 306
 307 int isis_recv_pdu_p2p(struct isis_circuit *circuit, uint8_t *ssnpa)
 308 {
 309         int bytesread, addr_len;
 310         struct sockaddr_ll s_addr;
 311
 312         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 313         addr_len = sizeof(s_addr);
 314
 315         /* we can read directly to the stream */
 316         (void)stream_recvfrom(
 317                 circuit->rcv_stream, circuit->fd, circuit->interface->mtu, 0,
 318                 (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
 319
 320         if (s_addr.sll_pkttype == PACKET_OUTGOING) {
 321                 /*  Read the packet into discard buff */
 322                 bytesread = recvfrom(circuit->fd, discard_buff,
 323                                      sizeof(discard_buff), MSG_DONTWAIT,
 324                                      (struct sockaddr *)&s_addr,
 325                                      (socklen_t *)&addr_len);
 326                 if (bytesread < 0)
 327                         zlog_warn("isis_recv_pdu_p2p(): recvfrom() failed");
 328                 return ISIS_WARNING;
 329         }
 330
 331         /* If we don't have protocol type 0x00FE which is
 332          * ISO over GRE we exit with pain :)
 333          */
 334         if (ntohs(s_addr.sll_protocol) != 0x00FE) {
 335                 zlog_warn("isis_recv_pdu_p2p(): protocol mismatch(): %X",
 336                           ntohs(s_addr.sll_protocol));
 337                 return ISIS_WARNING;
 338         }
 339
 340         memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
 341
 342         return ISIS_OK;
 343 }
 344
 345 int isis_send_pdu_bcast(struct isis_circuit *circuit, int level)
 346 {
 347         struct msghdr msg;
 348         struct iovec iov[2];
 349         char temp_buff[LLC_LEN];
 350
 351         /* we need to do the LLC in here because of P2P circuits, which will
 352          * not need it
 353          */
 354         struct sockaddr_ll sa;
 355
 356         stream_set_getp(circuit->snd_stream, 0);
 357         memset(&sa, 0, sizeof(struct sockaddr_ll));
 358         sa.sll_family = AF_PACKET;
 359
 360         size_t frame_size = stream_get_endp(circuit->snd_stream) + LLC_LEN;
 361         sa.sll_protocol = htons(isis_ethertype(frame_size));
 362         sa.sll_ifindex = circuit->interface->ifindex;
 363         sa.sll_halen = ETH_ALEN;
 364         /* RFC5309 section 4.1 recommends ALL_ISS */
 365         if (circuit->circ_type == CIRCUIT_T_P2P)
 366                 memcpy(&sa.sll_addr, ALL_ISS, ETH_ALEN);
 367         else if (level == 1)
 368                 memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
 369         else
 370                 memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
 371
 372         /* on a broadcast circuit */
 373         /* first we put the LLC in */
 374         temp_buff[0] = 0xFE;
 375         temp_buff[1] = 0xFE;
 376         temp_buff[2] = 0x03;
 377
 378         memset(&msg, 0, sizeof(msg));
 379         msg.msg_name = &sa;
 380         msg.msg_namelen = sizeof(struct sockaddr_ll);
 381         msg.msg_iov = iov;
 382         msg.msg_iovlen = 2;
 383         iov[0].iov_base = temp_buff;
 384         iov[0].iov_len = LLC_LEN;
 385         iov[1].iov_base = circuit->snd_stream->data;
 386         iov[1].iov_len = stream_get_endp(circuit->snd_stream);
 387
 388         if (sendmsg(circuit->fd, &msg, 0) < 0) {
 389                 zlog_warn("IS-IS pfpacket: could not transmit packet on %s: %s",
 390                           circuit->interface->name, safe_strerror(errno));
 391                 if (ERRNO_IO_RETRY(errno))
 392                         return ISIS_WARNING;
 393                 return ISIS_ERROR;
 394         }
 395         return ISIS_OK;
 396 }
 397
 398 int isis_send_pdu_p2p(struct isis_circuit *circuit, int level)
 399 {
 400         struct sockaddr_ll sa;
 401         ssize_t rv;
 402
 403         stream_set_getp(circuit->snd_stream, 0);
 404         memset(&sa, 0, sizeof(struct sockaddr_ll));
 405         sa.sll_family = AF_PACKET;
 406         sa.sll_ifindex = circuit->interface->ifindex;
 407         sa.sll_halen = ETH_ALEN;
 408         if (level == 1)
 409                 memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
 410         else
 411                 memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
 412
 413
 414         /* lets try correcting the protocol */
 415         sa.sll_protocol = htons(0x00FE);
 416         rv = sendto(circuit->fd, circuit->snd_stream->data,
 417                     stream_get_endp(circuit->snd_stream), 0,
 418                     (struct sockaddr *)&sa, sizeof(struct sockaddr_ll));
 419         if (rv < 0) {
 420                 zlog_warn("IS-IS pfpacket: could not transmit packet on %s: %s",
 421                           circuit->interface->name, safe_strerror(errno));
 422                 if (ERRNO_IO_RETRY(errno))
 423                         return ISIS_WARNING;
 424                 return ISIS_ERROR;
 425         }
 426         return ISIS_OK;
 427 }
 428
 429 #endif /* ISIS_METHOD == ISIS_METHOD_PFPACKET */