diff options
| -rw-r--r-- | lib/bfd.c | 414 | ||||
| -rw-r--r-- | lib/bfd.h | 17 |
2 files changed, 431 insertions, 0 deletions
@@ -34,6 +34,7 @@ #include "bfd.h" DEFINE_MTYPE_STATIC(LIB, BFD_INFO, "BFD info"); +DEFINE_MTYPE_STATIC(LIB, BFD_SOURCE, "BFD source cache"); /** * BFD protocol integration configuration. @@ -48,6 +49,29 @@ enum bfd_session_event { }; /** + * BFD source selection result cache. + * + * This structure will keep track of the result based on the destination + * prefix. When the result changes all related BFD sessions with automatic + * source will be updated. + */ +struct bfd_source_cache { + /** Address VRF belongs. */ + vrf_id_t vrf_id; + /** Destination network address. */ + struct prefix address; + /** Source selected. */ + struct prefix source; + /** Is the source address valid? */ + bool valid; + /** BFD sessions using this. */ + size_t refcount; + + SLIST_ENTRY(bfd_source_cache) entry; +}; +SLIST_HEAD(bfd_source_list, bfd_source_cache); + +/** * Data structure to do the necessary tricks to hide the BFD protocol * integration internals. */ @@ -82,6 +106,11 @@ struct bfd_session_params { /** BFD session installation state. */ bool installed; + /** Automatic source selection. */ + bool auto_source; + /** Currently selected source. */ + struct bfd_source_cache *source_cache; + /** Global BFD paramaters list. */ TAILQ_ENTRY(bfd_session_params) entry; }; @@ -92,11 +121,15 @@ struct bfd_sessions_global { * without code duplication among daemons. */ TAILQ_HEAD(bsplist, bfd_session_params) bsplist; + /** BFD automatic source selection cache. */ + struct bfd_source_list source_list; /** Pointer to FRR's event manager. */ struct thread_master *tm; /** Pointer to zebra client data structure. */ struct zclient *zc; + /** Zebra next hop tracking (NHT) client. */ + struct zclient *nht_zclient; /** Debugging state. */ bool debugging; @@ -111,6 +144,34 @@ static struct bfd_sessions_global bsglobal; static const struct in6_addr i6a_zero; /* + * Prototypes + */ +static void bfd_nht_zclient_connect(struct thread *thread); + +static void bfd_nht_zclient_connected(struct zclient *zclient); +static int bfd_nht_update(ZAPI_CALLBACK_ARGS); + +static void bfd_source_cache_get(struct bfd_session_params *session); +static void bfd_source_cache_put(struct bfd_session_params *session); + +static inline void +bfd_source_cache_register(const struct bfd_source_cache *source) +{ + zclient_send_rnh(bsglobal.nht_zclient, ZEBRA_NEXTHOP_REGISTER, + &source->address, SAFI_UNICAST, false, false, + source->vrf_id); +} + +static inline void +bfd_source_cache_unregister(const struct bfd_source_cache *source) +{ + zclient_send_rnh(bsglobal.nht_zclient, ZEBRA_NEXTHOP_UNREGISTER, + &source->address, SAFI_UNICAST, false, false, + source->vrf_id); +} + + +/* * bfd_get_peer_info - Extract the Peer information for which the BFD session * went down from the message sent from Zebra to clients. */ @@ -531,6 +592,8 @@ void bfd_sess_free(struct bfd_session_params **bsp) /* Remove from global list. */ TAILQ_REMOVE(&bsglobal.bsplist, (*bsp), entry); + bfd_source_cache_put(*bsp); + /* Free the memory and point to NULL. */ XFREE(MTYPE_BFD_INFO, (*bsp)); } @@ -565,6 +628,8 @@ void bfd_sess_set_ipv4_addrs(struct bfd_session_params *bsp, /* If already installed, remove the old setting. */ _bfd_sess_remove(bsp); + /* Address changed so we must reapply auto source. */ + bfd_source_cache_put(bsp); bsp->args.family = AF_INET; @@ -578,6 +643,9 @@ void bfd_sess_set_ipv4_addrs(struct bfd_session_params *bsp, assert(dst); memcpy(&bsp->args.dst, dst, sizeof(struct in_addr)); + + if (bsp->auto_source) + bfd_source_cache_get(bsp); } void bfd_sess_set_ipv6_addrs(struct bfd_session_params *bsp, @@ -589,6 +657,8 @@ void bfd_sess_set_ipv6_addrs(struct bfd_session_params *bsp, /* If already installed, remove the old setting. */ _bfd_sess_remove(bsp); + /* Address changed so we must reapply auto source. */ + bfd_source_cache_put(bsp); bsp->args.family = AF_INET6; @@ -600,6 +670,9 @@ void bfd_sess_set_ipv6_addrs(struct bfd_session_params *bsp, assert(dst); bsp->args.dst = *dst; + + if (bsp->auto_source) + bfd_source_cache_get(bsp); } void bfd_sess_set_interface(struct bfd_session_params *bsp, const char *ifname) @@ -646,8 +719,13 @@ void bfd_sess_set_vrf(struct bfd_session_params *bsp, vrf_id_t vrf_id) /* If already installed, remove the old setting. */ _bfd_sess_remove(bsp); + /* Address changed so we must reapply auto source. */ + bfd_source_cache_put(bsp); bsp->args.vrf_id = vrf_id; + + if (bsp->auto_source) + bfd_source_cache_get(bsp); } void bfd_sess_set_hop_count(struct bfd_session_params *bsp, uint8_t hops) @@ -677,6 +755,18 @@ void bfd_sess_set_timers(struct bfd_session_params *bsp, bsp->args.min_tx = min_tx; } +void bfd_sess_set_auto_source(struct bfd_session_params *bsp, bool enable) +{ + if (bsp->auto_source == enable) + return; + + bsp->auto_source = enable; + if (enable) + bfd_source_cache_get(bsp); + else + bfd_source_cache_put(bsp); +} + void bfd_sess_install(struct bfd_session_params *bsp) { bsp->lastev = BSE_INSTALL; @@ -746,6 +836,11 @@ void bfd_sess_timers(const struct bfd_session_params *bsp, *min_tx = bsp->args.min_tx; } +bool bfd_sess_auto_source(const struct bfd_session_params *bsp) +{ + return bsp->auto_source; +} + void bfd_sess_show(struct vty *vty, struct json_object *json, struct bfd_session_params *bsp) { @@ -950,10 +1045,17 @@ int zclient_bfd_session_update(ZAPI_CALLBACK_ARGS) return 0; } +static zclient_handler *const bfd_nht_handlers[] = { + [ZEBRA_NEXTHOP_UPDATE] = bfd_nht_update, +}; + void bfd_protocol_integration_init(struct zclient *zc, struct thread_master *tm) { + struct zclient_options bfd_nht_options = zclient_options_default; + /* Initialize data structure. */ TAILQ_INIT(&bsglobal.bsplist); + SLIST_INIT(&bsglobal.source_list); /* Copy pointers. */ bsglobal.zc = zc; @@ -964,6 +1066,16 @@ void bfd_protocol_integration_init(struct zclient *zc, struct thread_master *tm) /* Send the client registration */ bfd_client_sendmsg(zc, ZEBRA_BFD_CLIENT_REGISTER, VRF_DEFAULT); + + /* Start NHT client (for automatic source decisions). */ + bsglobal.nht_zclient = + zclient_new(tm, &bfd_nht_options, bfd_nht_handlers, + array_size(bfd_nht_handlers)); + bsglobal.nht_zclient->sock = -1; + bsglobal.nht_zclient->privs = zc->privs; + bsglobal.nht_zclient->zebra_connected = bfd_nht_zclient_connected; + thread_add_timer(tm, bfd_nht_zclient_connect, bsglobal.nht_zclient, 1, + &bsglobal.nht_zclient->t_connect); } void bfd_protocol_integration_set_debug(bool enable) @@ -985,3 +1097,305 @@ bool bfd_protocol_integration_shutting_down(void) { return bsglobal.shutting_down; } + +/* + * BFD automatic source selection + * + * This feature will use the next hop tracking (NHT) provided by zebra + * to find out the source address by looking at the output interface. + * + * When the interface address / routing table change we'll be notified + * and be able to update the source address accordingly. + * + * <daemon> zebra + * | + * +-----------------+ + * | BFD session set | + * | to auto source | + * +-----------------+ + * | + * \ +-----------------+ + * --------------> | Resolves | + * | destination | + * | address | + * +-----------------+ + * | + * +-----------------+ / + * | Sets resolved | <---------- + * | source address | + * +-----------------+ + */ +static bool +bfd_source_cache_session_match(const struct bfd_source_cache *source, + const struct bfd_session_params *session) +{ + const struct in_addr *address; + const struct in6_addr *address_v6; + + if (session->args.vrf_id != source->vrf_id) + return false; + if (session->args.family != source->address.family) + return false; + + switch (session->args.family) { + case AF_INET: + address = (const struct in_addr *)&session->args.dst; + if (address->s_addr != source->address.u.prefix4.s_addr) + return false; + break; + case AF_INET6: + address_v6 = &session->args.dst; + if (memcmp(address_v6, &source->address.u.prefix6, + sizeof(struct in6_addr))) + return false; + break; + default: + return false; + } + + return true; +} + +static struct bfd_source_cache * +bfd_source_cache_find(vrf_id_t vrf_id, const struct prefix *prefix) +{ + struct bfd_source_cache *source; + + SLIST_FOREACH (source, &bsglobal.source_list, entry) { + if (source->vrf_id != vrf_id) + continue; + if (!prefix_same(&source->address, prefix)) + continue; + + return source; + } + + return NULL; +} + +static void bfd_source_cache_get(struct bfd_session_params *session) +{ + struct bfd_source_cache *source; + struct prefix target = {}; + + switch (session->args.family) { + case AF_INET: + target.family = AF_INET; + target.prefixlen = IPV4_MAX_BITLEN; + memcpy(&target.u.prefix4, &session->args.dst, + sizeof(struct in_addr)); + break; + case AF_INET6: + target.family = AF_INET6; + target.prefixlen = IPV6_MAX_BITLEN; + memcpy(&target.u.prefix6, &session->args.dst, + sizeof(struct in6_addr)); + break; + default: + return; + } + + source = bfd_source_cache_find(session->args.vrf_id, &target); + if (source) { + if (session->source_cache == source) + return; + + bfd_source_cache_put(session); + session->source_cache = source; + source->refcount++; + return; + } + + source = XCALLOC(MTYPE_BFD_SOURCE, sizeof(*source)); + prefix_copy(&source->address, &target); + source->vrf_id = session->args.vrf_id; + SLIST_INSERT_HEAD(&bsglobal.source_list, source, entry); + + bfd_source_cache_put(session); + session->source_cache = source; + source->refcount = 1; + + bfd_source_cache_register(source); + + return; +} + +static void bfd_source_cache_put(struct bfd_session_params *session) +{ + if (session->source_cache == NULL) + return; + + session->source_cache->refcount--; + if (session->source_cache->refcount > 0) { + session->source_cache = NULL; + return; + } + + bfd_source_cache_unregister(session->source_cache); + SLIST_REMOVE(&bsglobal.source_list, session->source_cache, + bfd_source_cache, entry); + XFREE(MTYPE_BFD_SOURCE, session->source_cache); +} + +/** Updates BFD running session if source address has changed. */ +static void +bfd_source_cache_update_session(const struct bfd_source_cache *source, + struct bfd_session_params *session) +{ + const struct in_addr *address; + const struct in6_addr *address_v6; + + switch (session->args.family) { + case AF_INET: + address = (const struct in_addr *)&session->args.src; + if (memcmp(address, &source->source.u.prefix4, + sizeof(struct in_addr)) == 0) + return; + + _bfd_sess_remove(session); + memcpy(&session->args.src, &source->source.u.prefix4, + sizeof(struct in_addr)); + break; + case AF_INET6: + address_v6 = &session->args.src; + if (memcmp(address_v6, &source->source.u.prefix6, + sizeof(struct in6_addr)) == 0) + return; + + _bfd_sess_remove(session); + memcpy(&session->args.src, &source->source.u.prefix6, + sizeof(struct in6_addr)); + break; + default: + return; + } + + bfd_sess_install(session); +} + +static void +bfd_source_cache_update_sessions(const struct bfd_source_cache *source) +{ + struct bfd_session_params *session; + + if (!source->valid) + return; + + TAILQ_FOREACH (session, &bsglobal.bsplist, entry) { + if (!session->auto_source) + continue; + if (!bfd_source_cache_session_match(source, session)) + continue; + + bfd_source_cache_update_session(source, session); + } +} + +/** + * Try to translate next hop information into source address. + * + * \returns `true` if source changed otherwise `false`. + */ +static bool bfd_source_cache_update(struct bfd_source_cache *source, + const struct zapi_route *route) +{ + size_t nh_index; + + for (nh_index = 0; nh_index < route->nexthop_num; nh_index++) { + const struct zapi_nexthop *nh = &route->nexthops[nh_index]; + const struct interface *interface; + const struct connected *connected; + const struct listnode *node; + + interface = if_lookup_by_index(nh->ifindex, nh->vrf_id); + if (interface == NULL) { + zlog_err("next hop interface not found (index %d)", + nh->ifindex); + continue; + } + + for (ALL_LIST_ELEMENTS_RO(interface->connected, node, + connected)) { + if (source->address.family != + connected->address->family) + continue; + if (prefix_same(connected->address, &source->source)) + return false; + /* + * Skip link-local as it is only useful for single hop + * and in that case no source is specified usually. + */ + if (source->address.family == AF_INET6 && + IN6_IS_ADDR_LINKLOCAL( + &connected->address->u.prefix6)) + continue; + + prefix_copy(&source->source, connected->address); + source->valid = true; + return true; + } + } + + memset(&source->source, 0, sizeof(source->source)); + source->valid = false; + return false; +} + +static void bfd_nht_zclient_connect(struct thread *thread) +{ + struct zclient *zclient = THREAD_ARG(thread); + + if (bsglobal.debugging) + zlog_debug("BFD NHT zclient connection attempt"); + + if (zclient_start(zclient) == -1) { + if (bsglobal.debugging) + zlog_debug("BFD NHT zclient connection failed"); + + thread_add_timer(bsglobal.tm, bfd_nht_zclient_connect, zclient, + 3, &zclient->t_connect); + return; + } + + if (bsglobal.debugging) + zlog_debug("BFD NHT zclient connection succeeded"); +} + +static void bfd_nht_zclient_connected(struct zclient *zclient) +{ + struct bfd_source_cache *source; + + if (bsglobal.debugging) + zlog_debug("BFD NHT zclient connected"); + + SLIST_FOREACH (source, &bsglobal.source_list, entry) + bfd_source_cache_register(source); +} + +static int bfd_nht_update(ZAPI_CALLBACK_ARGS) +{ + struct bfd_source_cache *source; + struct zapi_route route; + struct prefix match; + + if (!zapi_nexthop_update_decode(zclient->ibuf, &match, &route)) { + zlog_warn("BFD NHT update decode failure"); + return 0; + } + if (cmd != ZEBRA_NEXTHOP_UPDATE) + return 0; + + if (bsglobal.debugging) + zlog_debug("BFD NHT update for %pFX", &route.prefix); + + SLIST_FOREACH (source, &bsglobal.source_list, entry) { + if (source->vrf_id != route.vrf_id) + continue; + if (!prefix_same(&match, &source->address)) + continue; + if (bfd_source_cache_update(source, &route)) + bfd_source_cache_update_sessions(source); + } + + return 0; +} @@ -222,6 +222,18 @@ void bfd_sess_set_timers(struct bfd_session_params *bsp, uint32_t min_tx); /** + * Configures the automatic source selection for the BFD session. + * + * NOTE: + * Setting this configuration will override the IP source value set by + * `bfd_sess_set_ipv4_addrs` or `bfd_sess_set_ipv6_addrs`. + * + * \param bsp BFD session parameters + * \param enable BFD automatic source selection state. + */ +void bfd_sess_set_auto_source(struct bfd_session_params *bsp, bool enable); + +/** * Installs or updates the BFD session based on the saved session arguments. * * NOTE: @@ -331,6 +343,11 @@ void bfd_sess_timers(const struct bfd_session_params *bsp, uint32_t *min_tx); /** + * Gets the automatic source selection state. + */ +bool bfd_sess_auto_source(const struct bfd_session_params *bsp); + +/** * Show BFD session configuration and status. If `json` is provided (e.g. not * `NULL`) then information will be inserted in object, otherwise printed to * `vty`. |