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 static void adj_bfd_cb(struct bfd_session_params *bsp,
  38                        const struct bfd_session_status *bss, void *arg)
  39 {
  40         struct isis_adjacency *adj = arg;
  41
  42         if (IS_DEBUG_BFD)
  43                 zlog_debug(
  44                         "ISIS-BFD: BFD changed status for adjacency %s old %s new %s",
  45                         isis_adj_name(adj),
  46                         bfd_get_status_str(bss->previous_state),
  47                         bfd_get_status_str(bss->state));
  48
  49         if (bss->state == BFD_STATUS_DOWN
  50             && bss->previous_state == BFD_STATUS_UP) {
  51                 adj->circuit->area->bfd_signalled_down = true;
  52                 isis_adj_state_change(&adj, ISIS_ADJ_DOWN,
  53                                       "bfd session went down");
  54         }
  55 }
  56
  57 static void bfd_handle_adj_down(struct isis_adjacency *adj)
  58 {
  59         bfd_sess_free(&adj->bfd_session);
  60 }
  61
  62 static void bfd_handle_adj_up(struct isis_adjacency *adj)
  63 {
  64         struct isis_circuit *circuit = adj->circuit;
  65         int family;
  66         union g_addr dst_ip;
  67         union g_addr src_ip;
  68         struct list *local_ips;
  69         struct prefix *local_ip;
  70
  71         if (!circuit->bfd_config.enabled) {
  72                 if (IS_DEBUG_BFD)
  73                         zlog_debug(
  74                                 "ISIS-BFD: skipping BFD initialization on adjacency with %s because BFD is not enabled for the circuit",
  75                                 isis_adj_name(adj));
  76                 goto out;
  77         }
  78
  79         /* If IS-IS IPv6 is configured wait for IPv6 address to be programmed
  80          * before starting up BFD
  81          */
  82         if (circuit->ipv6_router
  83             && (listcount(circuit->ipv6_link) == 0
  84                 || adj->ll_ipv6_count == 0)) {
  85                 if (IS_DEBUG_BFD)
  86                         zlog_debug(
  87                                 "ISIS-BFD: skipping BFD initialization on adjacency with %s because IPv6 is enabled but not ready",
  88                                 isis_adj_name(adj));
  89                 return;
  90         }
  91
  92         /*
  93          * If IS-IS is enabled for both IPv4 and IPv6 on the circuit, prefer
  94          * creating a BFD session over IPv6.
  95          */
  96         if (circuit->ipv6_router && adj->ll_ipv6_count) {
  97                 family = AF_INET6;
  98                 dst_ip.ipv6 = adj->ll_ipv6_addrs[0];
  99                 local_ips = circuit->ipv6_link;
 100                 if (list_isempty(local_ips)) {
 101                         if (IS_DEBUG_BFD)
 102                                 zlog_debug(
 103                                         "ISIS-BFD: skipping BFD initialization: IPv6 enabled and no local IPv6 addresses");
 104                         goto out;
 105                 }
 106                 local_ip = listgetdata(listhead(local_ips));
 107                 src_ip.ipv6 = local_ip->u.prefix6;
 108         } else if (circuit->ip_router && adj->ipv4_address_count) {
 109                 family = AF_INET;
 110                 dst_ip.ipv4 = adj->ipv4_addresses[0];
 111                 local_ips = fabricd_ip_addrs(adj->circuit);
 112                 if (!local_ips || list_isempty(local_ips)) {
 113                         if (IS_DEBUG_BFD)
 114                                 zlog_debug(
 115                                         "ISIS-BFD: skipping BFD initialization: IPv4 enabled and no local IPv4 addresses");
 116                         goto out;
 117                 }
 118                 local_ip = listgetdata(listhead(local_ips));
 119                 src_ip.ipv4 = local_ip->u.prefix4;
 120         } else
 121                 goto out;
 122
 123         if (adj->bfd_session == NULL)
 124                 adj->bfd_session = bfd_sess_new(adj_bfd_cb, adj);
 125
 126         bfd_sess_set_timers(adj->bfd_session, BFD_DEF_DETECT_MULT,
 127                             BFD_DEF_MIN_RX, BFD_DEF_MIN_TX);
 128         if (family == AF_INET)
 129                 bfd_sess_set_ipv4_addrs(adj->bfd_session, &src_ip.ipv4,
 130                                         &dst_ip.ipv4);
 131         else
 132                 bfd_sess_set_ipv6_addrs(adj->bfd_session, &src_ip.ipv6,
 133                                         &dst_ip.ipv6);
 134         bfd_sess_set_interface(adj->bfd_session, adj->circuit->interface->name);
 135         bfd_sess_set_vrf(adj->bfd_session,
 136                          adj->circuit->interface->vrf->vrf_id);
 137         bfd_sess_set_profile(adj->bfd_session, circuit->bfd_config.profile);
 138         bfd_sess_install(adj->bfd_session);
 139         return;
 140 out:
 141         bfd_handle_adj_down(adj);
 142 }
 143
 144 static int bfd_handle_adj_state_change(struct isis_adjacency *adj)
 145 {
 146         if (adj->adj_state == ISIS_ADJ_UP)
 147                 bfd_handle_adj_up(adj);
 148         else
 149                 bfd_handle_adj_down(adj);
 150         return 0;
 151 }
 152
 153 static void bfd_adj_cmd(struct isis_adjacency *adj)
 154 {
 155         if (adj->adj_state == ISIS_ADJ_UP && adj->circuit->bfd_config.enabled)
 156                 bfd_handle_adj_up(adj);
 157         else
 158                 bfd_handle_adj_down(adj);
 159 }
 160
 161 void isis_bfd_circuit_cmd(struct isis_circuit *circuit)
 162 {
 163         switch (circuit->circ_type) {
 164         case CIRCUIT_T_BROADCAST:
 165                 for (int level = ISIS_LEVEL1; level <= ISIS_LEVEL2; level++) {
 166                         struct list *adjdb = circuit->u.bc.adjdb[level - 1];
 167
 168                         struct listnode *node;
 169                         struct isis_adjacency *adj;
 170
 171                         if (!adjdb)
 172                                 continue;
 173                         for (ALL_LIST_ELEMENTS_RO(adjdb, node, adj))
 174                                 bfd_adj_cmd(adj);
 175                 }
 176                 break;
 177         case CIRCUIT_T_P2P:
 178                 if (circuit->u.p2p.neighbor)
 179                         bfd_adj_cmd(circuit->u.p2p.neighbor);
 180                 break;
 181         default:
 182                 break;
 183         }
 184 }
 185
 186 static int bfd_handle_adj_ip_enabled(struct isis_adjacency *adj, int family,
 187                                      bool global)
 188 {
 189
 190         if (family != AF_INET6 || global)
 191                 return 0;
 192
 193         if (adj->bfd_session)
 194                 return 0;
 195
 196         if (adj->adj_state != ISIS_ADJ_UP)
 197                 return 0;
 198
 199         bfd_handle_adj_up(adj);
 200
 201         return 0;
 202 }
 203
 204 static int bfd_handle_circuit_add_addr(struct isis_circuit *circuit)
 205 {
 206         struct isis_adjacency *adj;
 207         struct listnode *node;
 208
 209         if (circuit->area == NULL)
 210                 return 0;
 211
 212         for (ALL_LIST_ELEMENTS_RO(circuit->area->adjacency_list, node, adj)) {
 213                 if (adj->bfd_session)
 214                         continue;
 215
 216                 if (adj->adj_state != ISIS_ADJ_UP)
 217                         continue;
 218
 219                 bfd_handle_adj_up(adj);
 220         }
 221
 222         return 0;
 223 }
 224
 225 void isis_bfd_init(struct thread_master *tm)
 226 {
 227         bfd_protocol_integration_init(zclient, tm);
 228
 229         hook_register(isis_adj_state_change_hook, bfd_handle_adj_state_change);
 230         hook_register(isis_adj_ip_enabled_hook, bfd_handle_adj_ip_enabled);
 231         hook_register(isis_circuit_add_addr_hook, bfd_handle_circuit_add_addr);
 232 }