isisd/isis_bfd.c

   1 /*
   2  * IS-IS Rout(e)ing protocol - BFD support
   3  * Copyright (C) 2018 Christian Franke
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; either version 2 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19 #include <zebra.h>
  20
  21 #include "zclient.h"
  22 #include "nexthop.h"
  23 #include "bfd.h"
  24 #include "lib_errors.h"
  25
  26 #include "isisd/isis_bfd.h"
  27 #include "isisd/isis_zebra.h"
  28 #include "isisd/isis_common.h"
  29 #include "isisd/isis_constants.h"
  30 #include "isisd/isis_adjacency.h"
  31 #include "isisd/isis_circuit.h"
  32 #include "isisd/isisd.h"
  33 #include "isisd/fabricd.h"
  34
  35 DEFINE_MTYPE_STATIC(ISISD, BFD_SESSION, "ISIS BFD Session")
  36
  37 struct bfd_session {
  38         int family;
  39         union g_addr dst_ip;
  40         union g_addr src_ip;
  41         int status;
  42 };
  43
  44 static struct bfd_session *bfd_session_new(int family, union g_addr *dst_ip,
  45                                            union g_addr *src_ip)
  46 {
  47         struct bfd_session *rv;
  48
  49         rv = XCALLOC(MTYPE_BFD_SESSION, sizeof(*rv));
  50         rv->family = family;
  51         rv->dst_ip = *dst_ip;
  52         rv->src_ip = *src_ip;
  53         return rv;
  54 }
  55
  56 static void bfd_session_free(struct bfd_session **session)
  57 {
  58         if (!*session)
  59                 return;
  60
  61         XFREE(MTYPE_BFD_SESSION, *session);
  62         *session = NULL;
  63 }
  64
  65 static bool bfd_session_same(const struct bfd_session *session, int family,
  66                              const union g_addr *src, const union g_addr *dst)
  67 {
  68         if (session->family != family)
  69                 return false;
  70
  71         switch (session->family) {
  72         case AF_INET:
  73                 if (!IPV4_ADDR_SAME(&session->dst_ip.ipv4, &dst->ipv4))
  74                         return false;
  75                 if (!IPV4_ADDR_SAME(&session->src_ip.ipv4, &src->ipv4))
  76                         return false;
  77                 break;
  78         case AF_INET6:
  79                 if (!IPV6_ADDR_SAME(&session->dst_ip.ipv6, &dst->ipv6))
  80                         return false;
  81                 if (!IPV6_ADDR_SAME(&session->src_ip.ipv6, &src->ipv6))
  82                         return false;
  83                 break;
  84         default:
  85                 flog_err(EC_LIB_DEVELOPMENT, "%s: unknown address-family: %u",
  86                          __func__, session->family);
  87                 exit(1);
  88         }
  89
  90         return true;
  91 }
  92
  93 static void bfd_adj_event(struct isis_adjacency *adj, struct prefix *dst,
  94                           int new_status)
  95 {
  96         if (!adj->bfd_session)
  97                 return;
  98
  99         if (adj->bfd_session->family != dst->family)
 100                 return;
 101
 102         switch (adj->bfd_session->family) {
 103         case AF_INET:
 104                 if (!IPV4_ADDR_SAME(&adj->bfd_session->dst_ip.ipv4,
 105                                     &dst->u.prefix4))
 106                         return;
 107                 break;
 108         case AF_INET6:
 109                 if (!IPV6_ADDR_SAME(&adj->bfd_session->dst_ip.ipv6,
 110                                     &dst->u.prefix6))
 111                         return;
 112                 break;
 113         default:
 114                 flog_err(EC_LIB_DEVELOPMENT, "%s: unknown address-family: %u",
 115                          __func__, adj->bfd_session->family);
 116                 exit(1);
 117         }
 118
 119         int old_status = adj->bfd_session->status;
 120
 121         adj->bfd_session->status = new_status;
 122         if (old_status == new_status)
 123                 return;
 124
 125         if (isis->debugs & DEBUG_BFD) {
 126                 char dst_str[INET6_ADDRSTRLEN];
 127
 128                 inet_ntop(adj->bfd_session->family, &adj->bfd_session->dst_ip,
 129                           dst_str, sizeof(dst_str));
 130                 zlog_debug("ISIS-BFD: Peer %s on %s changed from %s to %s",
 131                            dst_str, adj->circuit->interface->name,
 132                            bfd_get_status_str(old_status),
 133                            bfd_get_status_str(new_status));
 134         }
 135
 136         if (old_status != BFD_STATUS_UP
 137             || new_status != BFD_STATUS_DOWN) {
 138                 return;
 139         }
 140
 141         isis_adj_state_change(adj, ISIS_ADJ_DOWN, "bfd session went down");
 142 }
 143
 144 static int isis_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
 145 {
 146         struct interface *ifp;
 147         struct prefix dst_ip;
 148         int status;
 149
 150         ifp = bfd_get_peer_info(zclient->ibuf, &dst_ip, NULL, &status,
 151                                 NULL, vrf_id);
 152         if (!ifp || (dst_ip.family != AF_INET && dst_ip.family != AF_INET6))
 153                 return 0;
 154
 155         if (isis->debugs & DEBUG_BFD) {
 156                 char dst_buf[INET6_ADDRSTRLEN];
 157
 158                 inet_ntop(dst_ip.family, &dst_ip.u.prefix, dst_buf,
 159                           sizeof(dst_buf));
 160
 161                 zlog_debug("ISIS-BFD: Received update for %s on %s: Changed state to %s",
 162                            dst_buf, ifp->name, bfd_get_status_str(status));
 163         }
 164
 165         struct isis_circuit *circuit = circuit_scan_by_ifp(ifp);
 166
 167         if (!circuit)
 168                 return 0;
 169
 170         if (circuit->circ_type == CIRCUIT_T_BROADCAST) {
 171                 for (int level = ISIS_LEVEL1; level <= ISIS_LEVEL2; level++) {
 172                         struct list *adjdb = circuit->u.bc.adjdb[level - 1];
 173
 174                         struct listnode *node, *nnode;
 175                         struct isis_adjacency *adj;
 176
 177                         for (ALL_LIST_ELEMENTS(adjdb, node, nnode, adj))
 178                                 bfd_adj_event(adj, &dst_ip, status);
 179                 }
 180         } else if (circuit->circ_type == CIRCUIT_T_P2P) {
 181                 if (circuit->u.p2p.neighbor) {
 182                         bfd_adj_event(circuit->u.p2p.neighbor,
 183                                       &dst_ip, status);
 184                 }
 185         }
 186
 187         return 0;
 188 }
 189
 190 static int isis_bfd_nbr_replay(ZAPI_CALLBACK_ARGS)
 191 {
 192         bfd_client_sendmsg(zclient, ZEBRA_BFD_CLIENT_REGISTER, vrf_id);
 193
 194         struct listnode *anode;
 195         struct isis_area *area;
 196
 197         if (isis->debugs & DEBUG_BFD)
 198                 zlog_debug("ISIS-BFD: Got neighbor replay request, resending neighbors.");
 199
 200         for (ALL_LIST_ELEMENTS_RO(isis->area_list, anode, area)) {
 201                 struct listnode *cnode;
 202                 struct isis_circuit *circuit;
 203
 204                 for (ALL_LIST_ELEMENTS_RO(area->circuit_list, cnode, circuit))
 205                         isis_bfd_circuit_cmd(circuit, ZEBRA_BFD_DEST_UPDATE);
 206         }
 207
 208         if (isis->debugs & DEBUG_BFD)
 209                 zlog_debug("ISIS-BFD: Done with replay.");
 210
 211         return 0;
 212 }
 213
 214 static void (*orig_zebra_connected)(struct zclient *);
 215 static void isis_bfd_zebra_connected(struct zclient *zclient)
 216 {
 217         if (orig_zebra_connected)
 218                 orig_zebra_connected(zclient);
 219
 220         bfd_client_sendmsg(zclient, ZEBRA_BFD_CLIENT_REGISTER, VRF_DEFAULT);
 221 }
 222
 223 static void bfd_debug(int family, union g_addr *dst, union g_addr *src,
 224                       const char *interface, int command)
 225 {
 226         if (!(isis->debugs & DEBUG_BFD))
 227                 return;
 228
 229         char dst_str[INET6_ADDRSTRLEN];
 230         char src_str[INET6_ADDRSTRLEN];
 231
 232         inet_ntop(family, dst, dst_str, sizeof(dst_str));
 233         inet_ntop(family, src, src_str, sizeof(src_str));
 234
 235         const char *command_str;
 236
 237         switch (command) {
 238         case ZEBRA_BFD_DEST_REGISTER:
 239                 command_str = "Register";
 240                 break;
 241         case ZEBRA_BFD_DEST_DEREGISTER:
 242                 command_str = "Deregister";
 243                 break;
 244         case ZEBRA_BFD_DEST_UPDATE:
 245                 command_str = "Update";
 246                 break;
 247         default:
 248                 command_str = "Unknown-Cmd";
 249                 break;
 250         }
 251
 252         zlog_debug("ISIS-BFD: %s peer %s on %s (src %s)",
 253                    command_str, dst_str, interface, src_str);
 254 }
 255
 256 static void bfd_handle_adj_down(struct isis_adjacency *adj)
 257 {
 258         if (!adj->bfd_session)
 259                 return;
 260
 261         bfd_debug(adj->bfd_session->family, &adj->bfd_session->dst_ip,
 262                   &adj->bfd_session->src_ip, adj->circuit->interface->name,
 263                   ZEBRA_BFD_DEST_DEREGISTER);
 264
 265         bfd_peer_sendmsg(zclient, NULL, adj->bfd_session->family,
 266                          &adj->bfd_session->dst_ip,
 267                          &adj->bfd_session->src_ip,
 268                          adj->circuit->interface->name,
 269                          0, /* ttl */
 270                          0, /* multihop */
 271                          1, /* control plane independent bit is on */
 272                          ZEBRA_BFD_DEST_DEREGISTER,
 273                          0, /* set_flag */
 274                          VRF_DEFAULT);
 275         bfd_session_free(&adj->bfd_session);
 276 }
 277
 278 static void bfd_handle_adj_up(struct isis_adjacency *adj, int command)
 279 {
 280         struct isis_circuit *circuit = adj->circuit;
 281         int family;
 282         union g_addr dst_ip;
 283         union g_addr src_ip;
 284         struct list *local_ips;
 285         struct prefix *local_ip;
 286
 287         if (!circuit->bfd_info)
 288                 goto out;
 289
 290         /*
 291          * If IS-IS is enabled for both IPv4 and IPv6 on the circuit, prefer
 292          * creating a BFD session over IPv6.
 293          */
 294         if (circuit->ipv6_router && adj->ipv6_address_count) {
 295                 family = AF_INET6;
 296                 dst_ip.ipv6 = adj->ipv6_addresses[0];
 297                 local_ips = circuit->ipv6_link;
 298                 if (!local_ips || list_isempty(local_ips))
 299                         goto out;
 300                 local_ip = listgetdata(listhead(local_ips));
 301                 src_ip.ipv6 = local_ip->u.prefix6;
 302         } else if (circuit->ip_router && adj->ipv4_address_count) {
 303                 family = AF_INET;
 304                 dst_ip.ipv4 = adj->ipv4_addresses[0];
 305                 local_ips = fabricd_ip_addrs(adj->circuit);
 306                 if (!local_ips || list_isempty(local_ips))
 307                         goto out;
 308                 local_ip = listgetdata(listhead(local_ips));
 309                 src_ip.ipv4 = local_ip->u.prefix4;
 310         } else
 311                 goto out;
 312
 313         if (adj->bfd_session) {
 314                 if (bfd_session_same(adj->bfd_session, family, &src_ip,
 315                                      &dst_ip))
 316                         bfd_handle_adj_down(adj);
 317         }
 318
 319         if (!adj->bfd_session)
 320                 adj->bfd_session = bfd_session_new(family, &dst_ip, &src_ip);
 321
 322         bfd_debug(adj->bfd_session->family, &adj->bfd_session->dst_ip,
 323                   &adj->bfd_session->src_ip, circuit->interface->name, command);
 324         bfd_peer_sendmsg(zclient, circuit->bfd_info, adj->bfd_session->family,
 325                          &adj->bfd_session->dst_ip,
 326                          &adj->bfd_session->src_ip,
 327                          circuit->interface->name,
 328                          0, /* ttl */
 329                          0, /* multihop */
 330                          1, /* control plane independent bit is on */
 331                          command,
 332                          0, /* set flag */
 333                          VRF_DEFAULT);
 334         return;
 335 out:
 336         bfd_handle_adj_down(adj);
 337 }
 338
 339 static int bfd_handle_adj_state_change(struct isis_adjacency *adj)
 340 {
 341         if (adj->adj_state == ISIS_ADJ_UP)
 342                 bfd_handle_adj_up(adj, ZEBRA_BFD_DEST_REGISTER);
 343         else
 344                 bfd_handle_adj_down(adj);
 345         return 0;
 346 }
 347
 348 static void bfd_adj_cmd(struct isis_adjacency *adj, int command)
 349 {
 350         if (adj->adj_state == ISIS_ADJ_UP
 351             && command != ZEBRA_BFD_DEST_DEREGISTER) {
 352                 bfd_handle_adj_up(adj, command);
 353         } else {
 354                 bfd_handle_adj_down(adj);
 355         }
 356 }
 357
 358 void isis_bfd_circuit_cmd(struct isis_circuit *circuit, int command)
 359 {
 360         switch (circuit->circ_type) {
 361         case CIRCUIT_T_BROADCAST:
 362                 for (int level = ISIS_LEVEL1; level <= ISIS_LEVEL2; level++) {
 363                         struct list *adjdb = circuit->u.bc.adjdb[level - 1];
 364
 365                         struct listnode *node;
 366                         struct isis_adjacency *adj;
 367
 368                         for (ALL_LIST_ELEMENTS_RO(adjdb, node, adj))
 369                                 bfd_adj_cmd(adj, command);
 370                 }
 371                 break;
 372         case CIRCUIT_T_P2P:
 373                 if (circuit->u.p2p.neighbor)
 374                         bfd_adj_cmd(circuit->u.p2p.neighbor, command);
 375                 break;
 376         default:
 377                 break;
 378         }
 379 }
 380
 381 void isis_bfd_circuit_param_set(struct isis_circuit *circuit,
 382                                 uint32_t min_rx, uint32_t min_tx,
 383                                 uint32_t detect_mult, int defaults)
 384 {
 385         int command = 0;
 386
 387         bfd_set_param(&circuit->bfd_info, min_rx,
 388                       min_tx, detect_mult, defaults, &command);
 389
 390         if (command)
 391                 isis_bfd_circuit_cmd(circuit, command);
 392 }
 393
 394 static int bfd_circuit_write_settings(struct isis_circuit *circuit,
 395                                       struct vty *vty)
 396 {
 397         struct bfd_info *bfd_info = circuit->bfd_info;
 398
 399         if (!bfd_info)
 400                 return 0;
 401
 402         vty_out(vty, " %s bfd\n", PROTO_NAME);
 403         return 1;
 404 }
 405
 406 void isis_bfd_init(void)
 407 {
 408         bfd_gbl_init();
 409
 410         orig_zebra_connected = zclient->zebra_connected;
 411         zclient->zebra_connected = isis_bfd_zebra_connected;
 412         zclient->interface_bfd_dest_update = isis_bfd_interface_dest_update;
 413         zclient->bfd_dest_replay = isis_bfd_nbr_replay;
 414         hook_register(isis_adj_state_change_hook,
 415                       bfd_handle_adj_state_change);
 416         hook_register(isis_circuit_config_write,
 417                       bfd_circuit_write_settings);
 418 }