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
  36 #include "isisd/dict.h"
  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 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 struct sock_fprog bpf = {
  62         .len = array_size(isisfilter),
  63         .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 uint8_t ALL_L1_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x14};
  72 uint8_t ALL_L2_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x15};
  73 uint8_t ALL_ISS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x05};
  74 uint8_t ALL_ESS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x04};
  75
  76 static uint8_t discard_buff[8192];
  77 static uint8_t sock_buff[8192];
  78
  79 /*
  80  * if level is 0 we are joining p2p multicast
  81  * FIXME: and the p2p multicast being ???
  82  */
  83 static int isis_multicast_join(int fd, int registerto, int if_num)
  84 {
  85         struct packet_mreq mreq;
  86
  87         memset(&mreq, 0, sizeof(mreq));
  88         mreq.mr_ifindex = if_num;
  89         if (registerto) {
  90                 mreq.mr_type = PACKET_MR_MULTICAST;
  91                 mreq.mr_alen = ETH_ALEN;
  92                 if (registerto == 1)
  93                         memcpy(&mreq.mr_address, ALL_L1_ISS, ETH_ALEN);
  94                 else if (registerto == 2)
  95                         memcpy(&mreq.mr_address, ALL_L2_ISS, ETH_ALEN);
  96                 else if (registerto == 3)
  97                         memcpy(&mreq.mr_address, ALL_ISS, ETH_ALEN);
  98                 else
  99                         memcpy(&mreq.mr_address, ALL_ESS, ETH_ALEN);
 100
 101         } else {
 102                 mreq.mr_type = PACKET_MR_ALLMULTI;
 103         }
 104 #ifdef EXTREME_DEBUG
 105         zlog_debug(
 106                 "isis_multicast_join(): fd=%d, reg_to=%d, if_num=%d, "
 107                 "address = %02x:%02x:%02x:%02x:%02x:%02x",
 108                 fd, registerto, if_num, mreq.mr_address[0], mreq.mr_address[1],
 109                 mreq.mr_address[2], mreq.mr_address[3], mreq.mr_address[4],
 110                 mreq.mr_address[5]);
 111 #endif /* EXTREME_DEBUG */
 112         if (setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq,
 113                        sizeof(struct packet_mreq))) {
 114                 zlog_warn("isis_multicast_join(): setsockopt(): %s",
 115                           safe_strerror(errno));
 116                 return ISIS_WARNING;
 117         }
 118
 119         return ISIS_OK;
 120 }
 121
 122 static int open_packet_socket(struct isis_circuit *circuit)
 123 {
 124         struct sockaddr_ll s_addr;
 125         int fd, retval = ISIS_OK;
 126
 127         fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL));
 128         if (fd < 0) {
 129                 zlog_warn("open_packet_socket(): socket() failed %s",
 130                           safe_strerror(errno));
 131                 return ISIS_WARNING;
 132         }
 133
 134         if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf))) {
 135                 zlog_warn("open_packet_socket(): SO_ATTACH_FILTER failed: %s",
 136                           safe_strerror(errno));
 137         }
 138
 139         /*
 140          * Bind to the physical interface
 141          */
 142         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 143         s_addr.sll_family = AF_PACKET;
 144         s_addr.sll_protocol = htons(ETH_P_ALL);
 145         s_addr.sll_ifindex = circuit->interface->ifindex;
 146
 147         if (bind(fd, (struct sockaddr *)(&s_addr), sizeof(struct sockaddr_ll))
 148             < 0) {
 149                 zlog_warn("open_packet_socket(): bind() failed: %s",
 150                           safe_strerror(errno));
 151                 close(fd);
 152                 return ISIS_WARNING;
 153         }
 154
 155         circuit->fd = fd;
 156
 157         if (if_is_broadcast(circuit->interface)) {
 158                 /*
 159                  * Join to multicast groups
 160                  * according to
 161                  * 8.4.2 - Broadcast subnetwork IIH PDUs
 162                  * FIXME: is there a case only one will fail??
 163                  */
 164                 /* joining ALL_L1_ISS */
 165                 retval |= isis_multicast_join(circuit->fd, 1,
 166                                               circuit->interface->ifindex);
 167                 /* joining ALL_L2_ISS */
 168                 retval |= isis_multicast_join(circuit->fd, 2,
 169                                               circuit->interface->ifindex);
 170                 /* joining ALL_ISS (used in RFC 5309 p2p-over-lan as well) */
 171                 retval |= isis_multicast_join(circuit->fd, 3,
 172                                               circuit->interface->ifindex);
 173         } else {
 174                 retval = isis_multicast_join(circuit->fd, 0,
 175                                              circuit->interface->ifindex);
 176         }
 177
 178         return retval;
 179 }
 180
 181 /*
 182  * Create the socket and set the tx/rx funcs
 183  */
 184 int isis_sock_init(struct isis_circuit *circuit)
 185 {
 186         int retval = ISIS_OK;
 187
 188         frr_elevate_privs(&isisd_privs) {
 189
 190                 retval = open_packet_socket(circuit);
 191
 192                 if (retval != ISIS_OK) {
 193                         zlog_warn("%s: could not initialize the socket",
 194                                   __func__);
 195                         break;
 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                         break;
 209                 }
 210         }
 211
 212         return retval;
 213 }
 214
 215 static inline int llc_check(uint8_t *llc)
 216 {
 217         if (*llc != ISO_SAP || *(llc + 1) != ISO_SAP || *(llc + 2) != 3)
 218                 return 0;
 219
 220         return 1;
 221 }
 222
 223 int isis_recv_pdu_bcast(struct isis_circuit *circuit, uint8_t *ssnpa)
 224 {
 225         int bytesread, addr_len;
 226         struct sockaddr_ll s_addr;
 227         uint8_t llc[LLC_LEN];
 228
 229         addr_len = sizeof(s_addr);
 230
 231         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 232
 233         bytesread =
 234                 recvfrom(circuit->fd, (void *)&llc, LLC_LEN, MSG_PEEK,
 235                          (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
 236
 237         if ((bytesread < 0)
 238             || (s_addr.sll_ifindex != (int)circuit->interface->ifindex)) {
 239                 if (bytesread < 0) {
 240                         zlog_warn(
 241                                 "isis_recv_packet_bcast(): ifname %s, fd %d, "
 242                                 "bytesread %d, recvfrom(): %s",
 243                                 circuit->interface->name, circuit->fd,
 244                                 bytesread, safe_strerror(errno));
 245                 }
 246                 if (s_addr.sll_ifindex != (int)circuit->interface->ifindex) {
 247                         zlog_warn(
 248                                 "packet is received on multiple interfaces: "
 249                                 "socket interface %d, circuit interface %d, "
 250                                 "packet type %u",
 251                                 s_addr.sll_ifindex, circuit->interface->ifindex,
 252                                 s_addr.sll_pkttype);
 253                 }
 254
 255                 /* get rid of the packet */
 256                 bytesread = recvfrom(circuit->fd, discard_buff,
 257                                      sizeof(discard_buff), MSG_DONTWAIT,
 258                                      (struct sockaddr *)&s_addr,
 259                                      (socklen_t *)&addr_len);
 260
 261                 if (bytesread < 0)
 262                         zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 263
 264                 return ISIS_WARNING;
 265         }
 266         /*
 267          * Filtering by llc field, discard packets sent by this host (other
 268          * circuit)
 269          */
 270         if (!llc_check(llc) || s_addr.sll_pkttype == PACKET_OUTGOING) {
 271                 /*  Read the packet into discard buff */
 272                 bytesread = recvfrom(circuit->fd, discard_buff,
 273                                      sizeof(discard_buff), MSG_DONTWAIT,
 274                                      (struct sockaddr *)&s_addr,
 275                                      (socklen_t *)&addr_len);
 276                 if (bytesread < 0)
 277                         zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 278                 return ISIS_WARNING;
 279         }
 280
 281         /* on lan we have to read to the static buff first */
 282         bytesread = recvfrom(circuit->fd, sock_buff, sizeof(sock_buff),
 283                              MSG_DONTWAIT, (struct sockaddr *)&s_addr,
 284                              (socklen_t *)&addr_len);
 285         if (bytesread < 0) {
 286                 zlog_warn("isis_recv_pdu_bcast(): recvfrom() failed");
 287                 return ISIS_WARNING;
 288         }
 289
 290         /* then we lose the LLC */
 291         stream_write(circuit->rcv_stream, sock_buff + LLC_LEN,
 292                      bytesread - LLC_LEN);
 293
 294         memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
 295
 296         return ISIS_OK;
 297 }
 298
 299 int isis_recv_pdu_p2p(struct isis_circuit *circuit, uint8_t *ssnpa)
 300 {
 301         int bytesread, addr_len;
 302         struct sockaddr_ll s_addr;
 303
 304         memset(&s_addr, 0, sizeof(struct sockaddr_ll));
 305         addr_len = sizeof(s_addr);
 306
 307         /* we can read directly to the stream */
 308         (void)stream_recvfrom(
 309                 circuit->rcv_stream, circuit->fd, circuit->interface->mtu, 0,
 310                 (struct sockaddr *)&s_addr, (socklen_t *)&addr_len);
 311
 312         if (s_addr.sll_pkttype == PACKET_OUTGOING) {
 313                 /*  Read the packet into discard buff */
 314                 bytesread = recvfrom(circuit->fd, discard_buff,
 315                                      sizeof(discard_buff), MSG_DONTWAIT,
 316                                      (struct sockaddr *)&s_addr,
 317                                      (socklen_t *)&addr_len);
 318                 if (bytesread < 0)
 319                         zlog_warn("isis_recv_pdu_p2p(): recvfrom() failed");
 320                 return ISIS_WARNING;
 321         }
 322
 323         /* If we don't have protocol type 0x00FE which is
 324          * ISO over GRE we exit with pain :)
 325          */
 326         if (ntohs(s_addr.sll_protocol) != 0x00FE) {
 327                 zlog_warn("isis_recv_pdu_p2p(): protocol mismatch(): %X",
 328                           ntohs(s_addr.sll_protocol));
 329                 return ISIS_WARNING;
 330         }
 331
 332         memcpy(ssnpa, &s_addr.sll_addr, s_addr.sll_halen);
 333
 334         return ISIS_OK;
 335 }
 336
 337 int isis_send_pdu_bcast(struct isis_circuit *circuit, int level)
 338 {
 339         struct msghdr msg;
 340         struct iovec iov[2];
 341
 342         /* we need to do the LLC in here because of P2P circuits, which will
 343          * not need it
 344          */
 345         struct sockaddr_ll sa;
 346
 347         stream_set_getp(circuit->snd_stream, 0);
 348         memset(&sa, 0, sizeof(struct sockaddr_ll));
 349         sa.sll_family = AF_PACKET;
 350
 351         size_t frame_size = stream_get_endp(circuit->snd_stream) + LLC_LEN;
 352         sa.sll_protocol = htons(isis_ethertype(frame_size));
 353         sa.sll_ifindex = circuit->interface->ifindex;
 354         sa.sll_halen = ETH_ALEN;
 355         /* RFC5309 section 4.1 recommends ALL_ISS */
 356         if (circuit->circ_type == CIRCUIT_T_P2P)
 357                 memcpy(&sa.sll_addr, ALL_ISS, ETH_ALEN);
 358         else if (level == 1)
 359                 memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
 360         else
 361                 memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
 362
 363         /* on a broadcast circuit */
 364         /* first we put the LLC in */
 365         sock_buff[0] = 0xFE;
 366         sock_buff[1] = 0xFE;
 367         sock_buff[2] = 0x03;
 368
 369         memset(&msg, 0, sizeof(msg));
 370         msg.msg_name = &sa;
 371         msg.msg_namelen = sizeof(struct sockaddr_ll);
 372         msg.msg_iov = iov;
 373         msg.msg_iovlen = 2;
 374         iov[0].iov_base = sock_buff;
 375         iov[0].iov_len = LLC_LEN;
 376         iov[1].iov_base = circuit->snd_stream->data;
 377         iov[1].iov_len = stream_get_endp(circuit->snd_stream);
 378
 379         if (sendmsg(circuit->fd, &msg, 0) < 0) {
 380                 zlog_warn("IS-IS pfpacket: could not transmit packet on %s: %s",
 381                           circuit->interface->name, safe_strerror(errno));
 382                 if (ERRNO_IO_RETRY(errno))
 383                         return ISIS_WARNING;
 384                 return ISIS_ERROR;
 385         }
 386         return ISIS_OK;
 387 }
 388
 389 int isis_send_pdu_p2p(struct isis_circuit *circuit, int level)
 390 {
 391         struct sockaddr_ll sa;
 392         ssize_t rv;
 393
 394         stream_set_getp(circuit->snd_stream, 0);
 395         memset(&sa, 0, sizeof(struct sockaddr_ll));
 396         sa.sll_family = AF_PACKET;
 397         sa.sll_ifindex = circuit->interface->ifindex;
 398         sa.sll_halen = ETH_ALEN;
 399         if (level == 1)
 400                 memcpy(&sa.sll_addr, ALL_L1_ISS, ETH_ALEN);
 401         else
 402                 memcpy(&sa.sll_addr, ALL_L2_ISS, ETH_ALEN);
 403
 404
 405         /* lets try correcting the protocol */
 406         sa.sll_protocol = htons(0x00FE);
 407         rv = sendto(circuit->fd, circuit->snd_stream->data,
 408                     stream_get_endp(circuit->snd_stream), 0,
 409                     (struct sockaddr *)&sa, sizeof(struct sockaddr_ll));
 410         if (rv < 0) {
 411                 zlog_warn("IS-IS pfpacket: could not transmit packet on %s: %s",
 412                           circuit->interface->name, safe_strerror(errno));
 413                 if (ERRNO_IO_RETRY(errno))
 414                         return ISIS_WARNING;
 415                 return ISIS_ERROR;
 416         }
 417         return ISIS_OK;
 418 }
 419
 420 #endif /* ISIS_METHOD == ISIS_METHOD_PFPACKET */