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 "bfd.h"
  23
  24 #include "isisd/isis_bfd.h"
  25 #include "isisd/isis_zebra.h"
  26 #include "isisd/isis_common.h"
  27 #include "isisd/isis_constants.h"
  28 #include "isisd/isis_adjacency.h"
  29 #include "isisd/isis_circuit.h"
  30 #include "isisd/isisd.h"
  31 #include "isisd/fabricd.h"
  32
  33 DEFINE_MTYPE_STATIC(ISISD, BFD_SESSION, "ISIS BFD Session")
  34
  35 struct bfd_session {
  36         struct in_addr dst_ip;
  37         struct in_addr src_ip;
  38         int status;
  39 };
  40
  41 static struct bfd_session *bfd_session_new(struct in_addr *dst_ip,
  42                                            struct in_addr *src_ip)
  43 {
  44         struct bfd_session *rv;
  45
  46         rv = XCALLOC(MTYPE_BFD_SESSION, sizeof(*rv));
  47         rv->dst_ip = *dst_ip;
  48         rv->src_ip = *src_ip;
  49         return rv;
  50 }
  51
  52 static void bfd_session_free(struct bfd_session **session)
  53 {
  54         if (!*session)
  55                 return;
  56
  57         XFREE(MTYPE_BFD_SESSION, *session);
  58         *session = NULL;
  59 }
  60
  61 static void bfd_adj_event(struct isis_adjacency *adj, struct prefix *dst,
  62                           int new_status)
  63 {
  64         if (!adj->bfd_session)
  65                 return;
  66
  67         if (adj->bfd_session->dst_ip.s_addr != dst->u.prefix4.s_addr)
  68                 return;
  69
  70         int old_status = adj->bfd_session->status;
  71
  72         adj->bfd_session->status = new_status;
  73         if (old_status == new_status)
  74                 return;
  75
  76         if (isis->debugs & DEBUG_BFD) {
  77                 char dst_str[INET6_ADDRSTRLEN];
  78
  79                 inet_ntop(AF_INET, &adj->bfd_session->dst_ip,
  80                           dst_str, sizeof(dst_str));
  81                 zlog_debug("ISIS-BFD: Peer %s on %s changed from %s to %s",
  82                            dst_str, adj->circuit->interface->name,
  83                            bfd_get_status_str(old_status),
  84                            bfd_get_status_str(new_status));
  85         }
  86
  87         if (old_status != BFD_STATUS_UP
  88             || new_status != BFD_STATUS_DOWN) {
  89                 return;
  90         }
  91
  92         isis_adj_state_change(adj, ISIS_ADJ_DOWN, "bfd session went down");
  93 }
  94
  95 static int isis_bfd_interface_dest_update(ZAPI_CALLBACK_ARGS)
  96 {
  97         struct interface *ifp;
  98         struct prefix dst_ip;
  99         int status;
 100
 101         ifp = bfd_get_peer_info(zclient->ibuf, &dst_ip, NULL, &status, vrf_id);
 102         if (!ifp || dst_ip.family != AF_INET)
 103                 return 0;
 104
 105         if (isis->debugs & DEBUG_BFD) {
 106                 char dst_buf[INET6_ADDRSTRLEN];
 107
 108                 inet_ntop(AF_INET, &dst_ip.u.prefix4,
 109                           dst_buf, sizeof(dst_buf));
 110
 111                 zlog_debug("ISIS-BFD: Received update for %s on %s: Changed state to %s",
 112                            dst_buf, ifp->name, bfd_get_status_str(status));
 113         }
 114
 115         struct isis_circuit *circuit = circuit_scan_by_ifp(ifp);
 116
 117         if (!circuit)
 118                 return 0;
 119
 120         if (circuit->circ_type == CIRCUIT_T_BROADCAST) {
 121                 for (int level = ISIS_LEVEL1; level <= ISIS_LEVEL2; level++) {
 122                         struct list *adjdb = circuit->u.bc.adjdb[level - 1];
 123
 124                         struct listnode *node, *nnode;
 125                         struct isis_adjacency *adj;
 126
 127                         for (ALL_LIST_ELEMENTS(adjdb, node, nnode, adj))
 128                                 bfd_adj_event(adj, &dst_ip, status);
 129                 }
 130         } else if (circuit->circ_type == CIRCUIT_T_P2P) {
 131                 if (circuit->u.p2p.neighbor) {
 132                         bfd_adj_event(circuit->u.p2p.neighbor,
 133                                       &dst_ip, status);
 134                 }
 135         }
 136
 137         return 0;
 138 }
 139
 140 static int isis_bfd_nbr_replay(ZAPI_CALLBACK_ARGS)
 141 {
 142         bfd_client_sendmsg(zclient, ZEBRA_BFD_CLIENT_REGISTER);
 143
 144         struct listnode *anode;
 145         struct isis_area *area;
 146
 147         if (isis->debugs & DEBUG_BFD)
 148                 zlog_debug("ISIS-BFD: Got neighbor replay request, resending neighbors.");
 149
 150         for (ALL_LIST_ELEMENTS_RO(isis->area_list, anode, area)) {
 151                 struct listnode *cnode;
 152                 struct isis_circuit *circuit;
 153
 154                 for (ALL_LIST_ELEMENTS_RO(area->circuit_list, cnode, circuit))
 155                         isis_bfd_circuit_cmd(circuit, ZEBRA_BFD_DEST_UPDATE);
 156         }
 157
 158         if (isis->debugs & DEBUG_BFD)
 159                 zlog_debug("ISIS-BFD: Done with replay.");
 160
 161         return 0;
 162 }
 163
 164 static void (*orig_zebra_connected)(struct zclient *);
 165 static void isis_bfd_zebra_connected(struct zclient *zclient)
 166 {
 167         if (orig_zebra_connected)
 168                 orig_zebra_connected(zclient);
 169
 170         bfd_client_sendmsg(zclient, ZEBRA_BFD_CLIENT_REGISTER);
 171 }
 172
 173 static void bfd_debug(struct in_addr *dst, struct in_addr *src,
 174                       const char *interface, int command)
 175 {
 176         if (!(isis->debugs & DEBUG_BFD))
 177                 return;
 178
 179         char dst_str[INET6_ADDRSTRLEN];
 180         char src_str[INET6_ADDRSTRLEN];
 181
 182         inet_ntop(AF_INET, dst, dst_str, sizeof(dst_str));
 183         inet_ntop(AF_INET, src, src_str, sizeof(src_str));
 184
 185         const char *command_str;
 186
 187         switch (command) {
 188         case ZEBRA_BFD_DEST_REGISTER:
 189                 command_str = "Register";
 190                 break;
 191         case ZEBRA_BFD_DEST_DEREGISTER:
 192                 command_str = "Deregister";
 193                 break;
 194         case ZEBRA_BFD_DEST_UPDATE:
 195                 command_str = "Update";
 196                 break;
 197         default:
 198                 command_str = "Unknown-Cmd";
 199                 break;
 200         }
 201
 202         zlog_debug("ISIS-BFD: %s peer %s on %s (src %s)",
 203                    command_str, dst_str, interface, src_str);
 204 }
 205
 206 static void bfd_handle_adj_down(struct isis_adjacency *adj)
 207 {
 208         if (!adj->bfd_session)
 209                 return;
 210
 211         bfd_debug(&adj->bfd_session->dst_ip, &adj->bfd_session->src_ip,
 212                   adj->circuit->interface->name, ZEBRA_BFD_DEST_DEREGISTER);
 213
 214         bfd_peer_sendmsg(zclient, NULL, AF_INET,
 215                          &adj->bfd_session->dst_ip,
 216                          &adj->bfd_session->src_ip,
 217                          adj->circuit->interface->name,
 218                          0, /* ttl */
 219                          0, /* multihop */
 220                          ZEBRA_BFD_DEST_DEREGISTER,
 221                          0, /* set_flag */
 222                          VRF_DEFAULT);
 223         bfd_session_free(&adj->bfd_session);
 224 }
 225
 226 static void bfd_handle_adj_up(struct isis_adjacency *adj, int command)
 227 {
 228         struct isis_circuit *circuit = adj->circuit;
 229
 230         if (!circuit->bfd_info
 231             || !circuit->ip_router
 232             || !adj->ipv4_address_count)
 233                 goto out;
 234
 235         struct list *local_ips = fabricd_ip_addrs(adj->circuit);
 236
 237         if (!local_ips)
 238                 goto out;
 239
 240         struct in_addr *dst_ip = &adj->ipv4_addresses[0];
 241         struct prefix_ipv4 *local_ip = listgetdata(listhead(local_ips));
 242         struct in_addr *src_ip = &local_ip->prefix;
 243
 244         if (adj->bfd_session) {
 245                 if (adj->bfd_session->dst_ip.s_addr != dst_ip->s_addr
 246                     || adj->bfd_session->src_ip.s_addr != src_ip->s_addr)
 247                         bfd_handle_adj_down(adj);
 248         }
 249
 250         if (!adj->bfd_session)
 251                 adj->bfd_session = bfd_session_new(dst_ip, src_ip);
 252
 253         bfd_debug(&adj->bfd_session->dst_ip, &adj->bfd_session->src_ip,
 254                   circuit->interface->name, command);
 255         bfd_peer_sendmsg(zclient, circuit->bfd_info, AF_INET,
 256                          &adj->bfd_session->dst_ip,
 257                          &adj->bfd_session->src_ip,
 258                          circuit->interface->name,
 259                          0, /* ttl */
 260                          0, /* multihop */
 261                          command,
 262                          0, /* set flag */
 263                          VRF_DEFAULT);
 264         return;
 265 out:
 266         bfd_handle_adj_down(adj);
 267 }
 268
 269 static int bfd_handle_adj_state_change(struct isis_adjacency *adj)
 270 {
 271         if (adj->adj_state == ISIS_ADJ_UP)
 272                 bfd_handle_adj_up(adj, ZEBRA_BFD_DEST_REGISTER);
 273         else
 274                 bfd_handle_adj_down(adj);
 275         return 0;
 276 }
 277
 278 static void bfd_adj_cmd(struct isis_adjacency *adj, int command)
 279 {
 280         if (adj->adj_state == ISIS_ADJ_UP
 281             && command != ZEBRA_BFD_DEST_DEREGISTER) {
 282                 bfd_handle_adj_up(adj, command);
 283         } else {
 284                 bfd_handle_adj_down(adj);
 285         }
 286 }
 287
 288 void isis_bfd_circuit_cmd(struct isis_circuit *circuit, int command)
 289 {
 290         switch (circuit->circ_type) {
 291         case CIRCUIT_T_BROADCAST:
 292                 for (int level = ISIS_LEVEL1; level <= ISIS_LEVEL2; level++) {
 293                         struct list *adjdb = circuit->u.bc.adjdb[level - 1];
 294
 295                         struct listnode *node;
 296                         struct isis_adjacency *adj;
 297
 298                         for (ALL_LIST_ELEMENTS_RO(adjdb, node, adj))
 299                                 bfd_adj_cmd(adj, command);
 300                 }
 301                 break;
 302         case CIRCUIT_T_P2P:
 303                 if (circuit->u.p2p.neighbor)
 304                         bfd_adj_cmd(circuit->u.p2p.neighbor, command);
 305                 break;
 306         default:
 307                 break;
 308         }
 309 }
 310
 311 void isis_bfd_circuit_param_set(struct isis_circuit *circuit,
 312                                 uint32_t min_rx, uint32_t min_tx,
 313                                 uint32_t detect_mult, int defaults)
 314 {
 315         int command = 0;
 316
 317         bfd_set_param(&circuit->bfd_info, min_rx,
 318                       min_tx, detect_mult, defaults, &command);
 319
 320         if (command)
 321                 isis_bfd_circuit_cmd(circuit, command);
 322 }
 323
 324 static int bfd_circuit_write_settings(struct isis_circuit *circuit,
 325                                       struct vty *vty)
 326 {
 327         struct bfd_info *bfd_info = circuit->bfd_info;
 328
 329         if (!bfd_info)
 330                 return 0;
 331
 332         vty_out(vty, " %s bfd\n", PROTO_NAME);
 333         return 1;
 334 }
 335
 336 void isis_bfd_init(void)
 337 {
 338         bfd_gbl_init();
 339
 340         orig_zebra_connected = zclient->zebra_connected;
 341         zclient->zebra_connected = isis_bfd_zebra_connected;
 342         zclient->interface_bfd_dest_update = isis_bfd_interface_dest_update;
 343         zclient->bfd_dest_replay = isis_bfd_nbr_replay;
 344         hook_register(isis_adj_state_change_hook,
 345                       bfd_handle_adj_state_change);
 346         hook_register(isis_circuit_config_write,
 347                       bfd_circuit_write_settings);
 348 }