isisd/isis_bfd.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * IS-IS Rout(e)ing protocol - BFD support
   4  * Copyright (C) 2018 Christian Franke
   5  */
   6 #include <zebra.h>
   7
   8 #include "zclient.h"
   9 #include "nexthop.h"
  10 #include "bfd.h"
  11 #include "lib_errors.h"
  12
  13 #include "isisd/isis_bfd.h"
  14 #include "isisd/isis_zebra.h"
  15 #include "isisd/isis_common.h"
  16 #include "isisd/isis_constants.h"
  17 #include "isisd/isis_adjacency.h"
  18 #include "isisd/isis_circuit.h"
  19 #include "isisd/isisd.h"
  20 #include "isisd/fabricd.h"
  21
  22 DEFINE_MTYPE_STATIC(ISISD, BFD_SESSION, "ISIS BFD Session");
  23
  24 static void adj_bfd_cb(struct bfd_session_params *bsp,
  25                        const struct bfd_session_status *bss, void *arg)
  26 {
  27         struct isis_adjacency *adj = arg;
  28
  29         if (IS_DEBUG_BFD)
  30                 zlog_debug(
  31                         "ISIS-BFD: BFD changed status for adjacency %s old %s new %s",
  32                         isis_adj_name(adj),
  33                         bfd_get_status_str(bss->previous_state),
  34                         bfd_get_status_str(bss->state));
  35
  36         if (bss->state == BFD_STATUS_DOWN
  37             && bss->previous_state == BFD_STATUS_UP) {
  38                 adj->circuit->area->bfd_signalled_down = true;
  39                 isis_adj_state_change(&adj, ISIS_ADJ_DOWN,
  40                                       "bfd session went down");
  41         }
  42 }
  43
  44 static void bfd_handle_adj_down(struct isis_adjacency *adj)
  45 {
  46         bfd_sess_free(&adj->bfd_session);
  47 }
  48
  49 static void bfd_handle_adj_up(struct isis_adjacency *adj)
  50 {
  51         struct isis_circuit *circuit = adj->circuit;
  52         int family;
  53         union g_addr dst_ip;
  54         union g_addr src_ip;
  55         struct list *local_ips;
  56         struct prefix *local_ip;
  57
  58         if (!circuit->bfd_config.enabled) {
  59                 if (IS_DEBUG_BFD)
  60                         zlog_debug(
  61                                 "ISIS-BFD: skipping BFD initialization on adjacency with %s because BFD is not enabled for the circuit",
  62                                 isis_adj_name(adj));
  63                 goto out;
  64         }
  65
  66         /* If IS-IS IPv6 is configured wait for IPv6 address to be programmed
  67          * before starting up BFD
  68          */
  69         if (circuit->ipv6_router
  70             && (listcount(circuit->ipv6_link) == 0
  71                 || adj->ll_ipv6_count == 0)) {
  72                 if (IS_DEBUG_BFD)
  73                         zlog_debug(
  74                                 "ISIS-BFD: skipping BFD initialization on adjacency with %s because IPv6 is enabled but not ready",
  75                                 isis_adj_name(adj));
  76                 return;
  77         }
  78
  79         /*
  80          * If IS-IS is enabled for both IPv4 and IPv6 on the circuit, prefer
  81          * creating a BFD session over IPv6.
  82          */
  83         if (circuit->ipv6_router && adj->ll_ipv6_count) {
  84                 family = AF_INET6;
  85                 dst_ip.ipv6 = adj->ll_ipv6_addrs[0];
  86                 local_ips = circuit->ipv6_link;
  87                 if (list_isempty(local_ips)) {
  88                         if (IS_DEBUG_BFD)
  89                                 zlog_debug(
  90                                         "ISIS-BFD: skipping BFD initialization: IPv6 enabled and no local IPv6 addresses");
  91                         goto out;
  92                 }
  93                 local_ip = listgetdata(listhead(local_ips));
  94                 src_ip.ipv6 = local_ip->u.prefix6;
  95         } else if (circuit->ip_router && adj->ipv4_address_count) {
  96                 family = AF_INET;
  97                 dst_ip.ipv4 = adj->ipv4_addresses[0];
  98                 local_ips = fabricd_ip_addrs(adj->circuit);
  99                 if (!local_ips || list_isempty(local_ips)) {
 100                         if (IS_DEBUG_BFD)
 101                                 zlog_debug(
 102                                         "ISIS-BFD: skipping BFD initialization: IPv4 enabled and no local IPv4 addresses");
 103                         goto out;
 104                 }
 105                 local_ip = listgetdata(listhead(local_ips));
 106                 src_ip.ipv4 = local_ip->u.prefix4;
 107         } else
 108                 goto out;
 109
 110         if (adj->bfd_session == NULL)
 111                 adj->bfd_session = bfd_sess_new(adj_bfd_cb, adj);
 112
 113         bfd_sess_set_timers(adj->bfd_session, BFD_DEF_DETECT_MULT,
 114                             BFD_DEF_MIN_RX, BFD_DEF_MIN_TX);
 115         if (family == AF_INET)
 116                 bfd_sess_set_ipv4_addrs(adj->bfd_session, &src_ip.ipv4,
 117                                         &dst_ip.ipv4);
 118         else
 119                 bfd_sess_set_ipv6_addrs(adj->bfd_session, &src_ip.ipv6,
 120                                         &dst_ip.ipv6);
 121         bfd_sess_set_interface(adj->bfd_session, adj->circuit->interface->name);
 122         bfd_sess_set_vrf(adj->bfd_session,
 123                          adj->circuit->interface->vrf->vrf_id);
 124         bfd_sess_set_profile(adj->bfd_session, circuit->bfd_config.profile);
 125         bfd_sess_install(adj->bfd_session);
 126         return;
 127 out:
 128         bfd_handle_adj_down(adj);
 129 }
 130
 131 static int bfd_handle_adj_state_change(struct isis_adjacency *adj)
 132 {
 133         if (adj->adj_state == ISIS_ADJ_UP)
 134                 bfd_handle_adj_up(adj);
 135         else
 136                 bfd_handle_adj_down(adj);
 137         return 0;
 138 }
 139
 140 static void bfd_adj_cmd(struct isis_adjacency *adj)
 141 {
 142         if (adj->adj_state == ISIS_ADJ_UP && adj->circuit->bfd_config.enabled)
 143                 bfd_handle_adj_up(adj);
 144         else
 145                 bfd_handle_adj_down(adj);
 146 }
 147
 148 void isis_bfd_circuit_cmd(struct isis_circuit *circuit)
 149 {
 150         switch (circuit->circ_type) {
 151         case CIRCUIT_T_BROADCAST:
 152                 for (int level = ISIS_LEVEL1; level <= ISIS_LEVEL2; level++) {
 153                         struct list *adjdb = circuit->u.bc.adjdb[level - 1];
 154
 155                         struct listnode *node;
 156                         struct isis_adjacency *adj;
 157
 158                         if (!adjdb)
 159                                 continue;
 160                         for (ALL_LIST_ELEMENTS_RO(adjdb, node, adj))
 161                                 bfd_adj_cmd(adj);
 162                 }
 163                 break;
 164         case CIRCUIT_T_P2P:
 165                 if (circuit->u.p2p.neighbor)
 166                         bfd_adj_cmd(circuit->u.p2p.neighbor);
 167                 break;
 168         default:
 169                 break;
 170         }
 171 }
 172
 173 static int bfd_handle_adj_ip_enabled(struct isis_adjacency *adj, int family,
 174                                      bool global)
 175 {
 176
 177         if (family != AF_INET6 || global)
 178                 return 0;
 179
 180         if (adj->bfd_session)
 181                 return 0;
 182
 183         if (adj->adj_state != ISIS_ADJ_UP)
 184                 return 0;
 185
 186         bfd_handle_adj_up(adj);
 187
 188         return 0;
 189 }
 190
 191 static int bfd_handle_circuit_add_addr(struct isis_circuit *circuit)
 192 {
 193         struct isis_adjacency *adj;
 194         struct listnode *node;
 195
 196         if (circuit->area == NULL)
 197                 return 0;
 198
 199         for (ALL_LIST_ELEMENTS_RO(circuit->area->adjacency_list, node, adj)) {
 200                 if (adj->bfd_session)
 201                         continue;
 202
 203                 if (adj->adj_state != ISIS_ADJ_UP)
 204                         continue;
 205
 206                 bfd_handle_adj_up(adj);
 207         }
 208
 209         return 0;
 210 }
 211
 212 void isis_bfd_init(struct event_loop *tm)
 213 {
 214         bfd_protocol_integration_init(zclient, tm);
 215
 216         hook_register(isis_adj_state_change_hook, bfd_handle_adj_state_change);
 217         hook_register(isis_adj_ip_enabled_hook, bfd_handle_adj_ip_enabled);
 218         hook_register(isis_circuit_add_addr_hook, bfd_handle_circuit_add_addr);
 219 }