/* * BIRD -- The Border Gateway Protocol * * (c) 2000 Martin Mares * * Can be freely distributed and used under the terms of the GNU GPL. */ /** * DOC: Border Gateway Protocol * * The BGP protocol is implemented in three parts: |bgp.c| which takes care of the * connection and most of the interface with BIRD core, |packets.c| handling * both incoming and outgoing BGP packets and |attrs.c| containing functions for * manipulation with BGP attribute lists. * * As opposed to the other existing routing daemons, BIRD has a sophisticated core * architecture which is able to keep all the information needed by BGP in the * primary routing table, therefore no complex data structures like a central * BGP table are needed. This increases memory footprint of a BGP router with * many connections, but not too much and, which is more important, it makes * BGP much easier to implement. * * Each instance of BGP (corresponding to a single BGP peer) is described by a &bgp_proto * structure to which are attached individual connections represented by &bgp_connection * (usually, there exists only one connection, but during BGP session setup, there * can be more of them). The connections are handled according to the BGP state machine * defined in the RFC with all the timers and all the parameters configurable. * * In incoming direction, we listen on the connection's socket and each time we receive * some input, we pass it to bgp_rx(). It decodes packet headers and the markers and * passes complete packets to bgp_rx_packet() which distributes the packet according * to its type. * * In outgoing direction, we gather all the routing updates and sort them to buckets * (&bgp_bucket) according to their attributes (we keep a hash table for fast comparison * of &rta's and a &fib which helps us to find if we already have another route for * the same destination queued for sending, so that we can replace it with the new one * immediately instead of sending both updates). There also exists a special bucket holding * all the route withdrawals which cannot be queued anywhere else as they don't have any * attributes. If we have any packet to send (due to either new routes or the connection * tracking code wanting to send a Open, Keepalive or Notification message), we call * bgp_schedule_packet() which sets the corresponding bit in a @packet_to_send * bit field in &bgp_conn and as soon as the transmit socket buffer becomes empty, * we call bgp_fire_tx(). It inspects state of all the packet type bits and calls * the corresponding bgp_create_xx() functions, eventually rescheduling the same packet * type if we have more data of the same type to send. * * The processing of attributes consists of two functions: bgp_decode_attrs() for checking * of the attribute blocks and translating them to the language of BIRD's extended attributes * and bgp_encode_attrs() which does the converse. Both functions are built around a * @bgp_attr_table array describing all important characteristics of all known attributes. * Unknown transitive attributes are attached to the route as %EAF_TYPE_OPAQUE byte streams. */ #undef LOCAL_DEBUG #include "nest/bird.h" #include "nest/iface.h" #include "nest/protocol.h" #include "nest/route.h" #include "nest/locks.h" #include "nest/cli.h" #include "conf/conf.h" #include "lib/socket.h" #include "lib/resource.h" #include "lib/string.h" #include "bgp.h" struct linpool *bgp_linpool; /* Global temporary pool */ static sock *bgp_listen_sk; /* Global listening socket */ static int bgp_counter; /* Number of protocol instances using the listening socket */ static void bgp_close(struct bgp_proto *p, int apply_md5); static void bgp_connect(struct bgp_proto *p); static void bgp_active(struct bgp_proto *p); static sock *bgp_setup_listen_sk(ip_addr addr, unsigned port, u32 flags); /** * bgp_open - open a BGP instance * @p: BGP instance * * This function allocates and configures shared BGP resources. * Should be called as the last step during initialization * (when lock is acquired and neighbor is ready). * When error, state changed to PS_DOWN, -1 is returned and caller * should return immediately. */ static int bgp_open(struct bgp_proto *p) { struct config *cfg = p->cf->c.global; int errcode; bgp_counter++; if (!bgp_listen_sk) bgp_listen_sk = bgp_setup_listen_sk(cfg->listen_bgp_addr, cfg->listen_bgp_port, cfg->listen_bgp_flags); if (!bgp_listen_sk) { bgp_counter--; errcode = BEM_NO_SOCKET; goto err; } if (!bgp_linpool) bgp_linpool = lp_new(&root_pool, 4080); if (p->cf->password) { int rv = sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, p->cf->iface, p->cf->password); if (rv < 0) { bgp_close(p, 0); errcode = BEM_INVALID_MD5; goto err; } } return 0; err: p->p.disabled = 1; bgp_store_error(p, NULL, BE_MISC, errcode); proto_notify_state(&p->p, PS_DOWN); return -1; } static void bgp_startup(struct bgp_proto *p) { BGP_TRACE(D_EVENTS, "Started"); p->start_state = p->cf->capabilities ? BSS_CONNECT : BSS_CONNECT_NOCAP; if (!p->cf->passive) bgp_active(p); } static void bgp_startup_timeout(timer *t) { bgp_startup(t->data); } static void bgp_initiate(struct bgp_proto *p) { int rv = bgp_open(p); if (rv < 0) return; if (p->startup_delay) { BGP_TRACE(D_EVENTS, "Startup delayed by %d seconds", p->startup_delay); bgp_start_timer(p->startup_timer, p->startup_delay); } else bgp_startup(p); } /** * bgp_close - close a BGP instance * @p: BGP instance * @apply_md5: 0 to disable unsetting MD5 auth * * This function frees and deconfigures shared BGP resources. * @apply_md5 is set to 0 when bgp_close is called as a cleanup * from failed bgp_open(). */ static void bgp_close(struct bgp_proto *p, int apply_md5) { ASSERT(bgp_counter); bgp_counter--; if (p->cf->password && apply_md5) sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, p->cf->iface, NULL); if (!bgp_counter) { rfree(bgp_listen_sk); bgp_listen_sk = NULL; rfree(bgp_linpool); bgp_linpool = NULL; } } /** * bgp_start_timer - start a BGP timer * @t: timer * @value: time to fire (0 to disable the timer) * * This functions calls tm_start() on @t with time @value and the * amount of randomization suggested by the BGP standard. Please use * it for all BGP timers. */ void bgp_start_timer(timer *t, int value) { if (value) { /* The randomization procedure is specified in RFC 1771: 9.2.3.3 */ t->randomize = value / 4; tm_start(t, value - t->randomize); } else tm_stop(t); } /** * bgp_close_conn - close a BGP connection * @conn: connection to close * * This function takes a connection described by the &bgp_conn structure, * closes its socket and frees all resources associated with it. */ void bgp_close_conn(struct bgp_conn *conn) { // struct bgp_proto *p = conn->bgp; DBG("BGP: Closing connection\n"); conn->packets_to_send = 0; rfree(conn->connect_retry_timer); conn->connect_retry_timer = NULL; rfree(conn->keepalive_timer); conn->keepalive_timer = NULL; rfree(conn->hold_timer); conn->hold_timer = NULL; rfree(conn->sk); conn->sk = NULL; rfree(conn->tx_ev); conn->tx_ev = NULL; } /** * bgp_update_startup_delay - update a startup delay * @p: BGP instance * * This function updates a startup delay that is used to postpone next BGP connect. * It also handles disable_after_error and might stop BGP instance when error * happened and disable_after_error is on. * * It should be called when BGP protocol error happened. */ void bgp_update_startup_delay(struct bgp_proto *p) { struct bgp_config *cf = p->cf; DBG("BGP: Updating startup delay\n"); if (p->last_proto_error && ((now - p->last_proto_error) >= (int) cf->error_amnesia_time)) p->startup_delay = 0; p->last_proto_error = now; if (cf->disable_after_error) { p->startup_delay = 0; p->p.disabled = 1; return; } if (!p->startup_delay) p->startup_delay = cf->error_delay_time_min; else p->startup_delay = MIN(2 * p->startup_delay, cf->error_delay_time_max); } static void bgp_graceful_close_conn(struct bgp_conn *conn, unsigned subcode) { switch (conn->state) { case BS_IDLE: case BS_CLOSE: return; case BS_CONNECT: case BS_ACTIVE: bgp_conn_enter_idle_state(conn); return; case BS_OPENSENT: case BS_OPENCONFIRM: case BS_ESTABLISHED: bgp_error(conn, 6, subcode, NULL, 0); return; default: bug("bgp_graceful_close_conn: Unknown state %d", conn->state); } } static void bgp_down(struct bgp_proto *p) { if (p->start_state > BSS_PREPARE) bgp_close(p, 1); BGP_TRACE(D_EVENTS, "Down"); proto_notify_state(&p->p, PS_DOWN); } static void bgp_decision(void *vp) { struct bgp_proto *p = vp; DBG("BGP: Decision start\n"); if ((p->p.proto_state == PS_START) && (p->outgoing_conn.state == BS_IDLE) && (!p->cf->passive)) bgp_active(p); if ((p->p.proto_state == PS_STOP) && (p->outgoing_conn.state == BS_IDLE) && (p->incoming_conn.state == BS_IDLE)) bgp_down(p); } void bgp_stop(struct bgp_proto *p, unsigned subcode) { proto_notify_state(&p->p, PS_STOP); bgp_graceful_close_conn(&p->outgoing_conn, subcode); bgp_graceful_close_conn(&p->incoming_conn, subcode); ev_schedule(p->event); } static inline void bgp_conn_set_state(struct bgp_conn *conn, unsigned new_state) { if (conn->bgp->p.mrtdump & MD_STATES) mrt_dump_bgp_state_change(conn, conn->state, new_state); conn->state = new_state; } void bgp_conn_enter_openconfirm_state(struct bgp_conn *conn) { /* Really, most of the work is done in bgp_rx_open(). */ bgp_conn_set_state(conn, BS_OPENCONFIRM); } void bgp_conn_enter_established_state(struct bgp_conn *conn) { struct bgp_proto *p = conn->bgp; BGP_TRACE(D_EVENTS, "BGP session established"); DBG("BGP: UP!!!\n"); /* For multi-hop BGP sessions */ if (ipa_zero(p->source_addr)) p->source_addr = conn->sk->saddr; p->conn = conn; p->last_error_class = 0; p->last_error_code = 0; bgp_attr_init(conn->bgp); bgp_conn_set_state(conn, BS_ESTABLISHED); proto_notify_state(&p->p, PS_UP); } static void bgp_conn_leave_established_state(struct bgp_proto *p) { BGP_TRACE(D_EVENTS, "BGP session closed"); p->conn = NULL; if (p->p.proto_state == PS_UP) bgp_stop(p, 0); } void bgp_conn_enter_close_state(struct bgp_conn *conn) { struct bgp_proto *p = conn->bgp; int os = conn->state; bgp_conn_set_state(conn, BS_CLOSE); tm_stop(conn->hold_timer); tm_stop(conn->keepalive_timer); conn->sk->rx_hook = NULL; if (os == BS_ESTABLISHED) bgp_conn_leave_established_state(p); } void bgp_conn_enter_idle_state(struct bgp_conn *conn) { struct bgp_proto *p = conn->bgp; int os = conn->state; bgp_close_conn(conn); bgp_conn_set_state(conn, BS_IDLE); ev_schedule(p->event); if (os == BS_ESTABLISHED) bgp_conn_leave_established_state(p); } static void bgp_send_open(struct bgp_conn *conn) { conn->start_state = conn->bgp->start_state; conn->want_as4_support = conn->bgp->cf->enable_as4 && (conn->start_state != BSS_CONNECT_NOCAP); conn->peer_as4_support = 0; // Default value, possibly changed by receiving capability. conn->advertised_as = 0; DBG("BGP: Sending open\n"); conn->sk->rx_hook = bgp_rx; conn->sk->tx_hook = bgp_tx; tm_stop(conn->connect_retry_timer); bgp_schedule_packet(conn, PKT_OPEN); bgp_conn_set_state(conn, BS_OPENSENT); bgp_start_timer(conn->hold_timer, conn->bgp->cf->initial_hold_time); } static void bgp_connected(sock *sk) { struct bgp_conn *conn = sk->data; struct bgp_proto *p = conn->bgp; BGP_TRACE(D_EVENTS, "Connected"); bgp_send_open(conn); } static void bgp_connect_timeout(timer *t) { struct bgp_conn *conn = t->data; struct bgp_proto *p = conn->bgp; DBG("BGP: connect_timeout\n"); if (p->p.proto_state == PS_START) { bgp_close_conn(conn); bgp_connect(p); } else bgp_conn_enter_idle_state(conn); } static void bgp_sock_err(sock *sk, int err) { struct bgp_conn *conn = sk->data; struct bgp_proto *p = conn->bgp; /* * This error hook may be called either asynchronously from main * loop, or synchronously from sk_send(). But sk_send() is called * only from bgp_tx() and bgp_kick_tx(), which are both called * asynchronously from main loop. Moreover, they end if err hook is * called. Therefore, we could suppose that it is always called * asynchronously. */ bgp_store_error(p, conn, BE_SOCKET, err); if (err) BGP_TRACE(D_EVENTS, "Connection lost (%M)", err); else BGP_TRACE(D_EVENTS, "Connection closed"); bgp_conn_enter_idle_state(conn); } static void bgp_hold_timeout(timer *t) { struct bgp_conn *conn = t->data; DBG("BGP: Hold timeout\n"); /* If there is something in input queue, we are probably congested and perhaps just not processed BGP packets in time. */ if (sk_rx_ready(conn->sk) > 0) bgp_start_timer(conn->hold_timer, 10); else bgp_error(conn, 4, 0, NULL, 0); } static void bgp_keepalive_timeout(timer *t) { struct bgp_conn *conn = t->data; DBG("BGP: Keepalive timer\n"); bgp_schedule_packet(conn, PKT_KEEPALIVE); } static void bgp_setup_conn(struct bgp_proto *p, struct bgp_conn *conn) { timer *t; conn->sk = NULL; conn->bgp = p; conn->packets_to_send = 0; t = conn->connect_retry_timer = tm_new(p->p.pool); t->hook = bgp_connect_timeout; t->data = conn; t = conn->hold_timer = tm_new(p->p.pool); t->hook = bgp_hold_timeout; t->data = conn; t = conn->keepalive_timer = tm_new(p->p.pool); t->hook = bgp_keepalive_timeout; t->data = conn; conn->tx_ev = ev_new(p->p.pool); conn->tx_ev->hook = bgp_kick_tx; conn->tx_ev->data = conn; } static void bgp_setup_sk(struct bgp_conn *conn, sock *s) { s->data = conn; s->err_hook = bgp_sock_err; conn->sk = s; } static void bgp_active(struct bgp_proto *p) { int delay = MAX(1, p->cf->start_delay_time); struct bgp_conn *conn = &p->outgoing_conn; BGP_TRACE(D_EVENTS, "Connect delayed by %d seconds", delay); bgp_setup_conn(p, conn); bgp_conn_set_state(conn, BS_ACTIVE); bgp_start_timer(conn->connect_retry_timer, delay); } int bgp_apply_limits(struct bgp_proto *p) { if (p->cf->route_limit && (p->p.stats.imp_routes > p->cf->route_limit)) { log(L_WARN "%s: Route limit exceeded, shutting down", p->p.name); bgp_store_error(p, NULL, BE_AUTO_DOWN, BEA_ROUTE_LIMIT_EXCEEDED); bgp_update_startup_delay(p); bgp_stop(p, 1); // Errcode 6, 1 - max number of prefixes reached return -1; } return 0; } /** * bgp_connect - initiate an outgoing connection * @p: BGP instance * * The bgp_connect() function creates a new &bgp_conn and initiates * a TCP connection to the peer. The rest of connection setup is governed * by the BGP state machine as described in the standard. */ static void bgp_connect(struct bgp_proto *p) /* Enter Connect state and start establishing connection */ { sock *s; struct bgp_conn *conn = &p->outgoing_conn; int hops = p->cf->multihop ? : 1; DBG("BGP: Connecting\n"); s = sk_new(p->p.pool); s->type = SK_TCP_ACTIVE; s->saddr = p->source_addr; s->daddr = p->cf->remote_ip; s->iface = p->neigh ? p->neigh->iface : NULL; s->dport = BGP_PORT; s->ttl = p->cf->ttl_security ? 255 : hops; s->rbsize = BGP_RX_BUFFER_SIZE; s->tbsize = BGP_TX_BUFFER_SIZE; s->tos = IP_PREC_INTERNET_CONTROL; s->password = p->cf->password; s->tx_hook = bgp_connected; BGP_TRACE(D_EVENTS, "Connecting to %I%J from local address %I%J", s->daddr, p->cf->iface, s->saddr, ipa_has_link_scope(s->saddr) ? s->iface : NULL); bgp_setup_conn(p, conn); bgp_setup_sk(conn, s); bgp_conn_set_state(conn, BS_CONNECT); if (sk_open(s) < 0) { bgp_sock_err(s, 0); return; } /* Set minimal receive TTL if needed */ if (p->cf->ttl_security) { DBG("Setting minimum received TTL to %d", 256 - hops); if (sk_set_min_ttl(s, 256 - hops) < 0) { log(L_ERR "TTL security configuration failed, closing session"); bgp_sock_err(s, 0); return; } } DBG("BGP: Waiting for connect success\n"); bgp_start_timer(conn->connect_retry_timer, p->cf->connect_retry_time); } /** * bgp_incoming_connection - handle an incoming connection * @sk: TCP socket * @dummy: unused * * This function serves as a socket hook for accepting of new BGP * connections. It searches a BGP instance corresponding to the peer * which has connected and if such an instance exists, it creates a * &bgp_conn structure, attaches it to the instance and either sends * an Open message or (if there already is an active connection) it * closes the new connection by sending a Notification message. */ static int bgp_incoming_connection(sock *sk, int dummy UNUSED) { struct proto_config *pc; DBG("BGP: Incoming connection from %I port %d\n", sk->daddr, sk->dport); WALK_LIST(pc, config->protos) if (pc->protocol == &proto_bgp && pc->proto) { struct bgp_proto *p = (struct bgp_proto *) pc->proto; if (ipa_equal(p->cf->remote_ip, sk->daddr) && (!ipa_has_link_scope(sk->daddr) || (p->cf->iface == sk->iface))) { /* We are in proper state and there is no other incoming connection */ int acc = (p->p.proto_state == PS_START || p->p.proto_state == PS_UP) && (p->start_state >= BSS_CONNECT) && (!p->incoming_conn.sk); BGP_TRACE(D_EVENTS, "Incoming connection from %I%J (port %d) %s", sk->daddr, ipa_has_link_scope(sk->daddr) ? sk->iface : NULL, sk->dport, acc ? "accepted" : "rejected"); if (!acc) goto err; int hops = p->cf->multihop ? : 1; if (p->cf->ttl_security) { /* TTL security support */ if ((sk_set_ttl(sk, 255) < 0) || (sk_set_min_ttl(sk, 256 - hops) < 0)) { log(L_ERR "TTL security configuration failed, closing session"); goto err; } } else sk_set_ttl(sk, hops); bgp_setup_conn(p, &p->incoming_conn); bgp_setup_sk(&p->incoming_conn, sk); bgp_send_open(&p->incoming_conn); return 0; } } log(L_WARN "BGP: Unexpected connect from unknown address %I%J (port %d)", sk->daddr, ipa_has_link_scope(sk->daddr) ? sk->iface : NULL, sk->dport); err: rfree(sk); return 0; } static void bgp_listen_sock_err(sock *sk UNUSED, int err) { if (err == ECONNABORTED) log(L_WARN "BGP: Incoming connection aborted"); else log(L_ERR "BGP: Error on listening socket: %M", err); } static sock * bgp_setup_listen_sk(ip_addr addr, unsigned port, u32 flags) { sock *s = sk_new(&root_pool); DBG("BGP: Creating listening socket\n"); s->type = SK_TCP_PASSIVE; s->ttl = 255; s->saddr = addr; s->sport = port ? port : BGP_PORT; s->flags = flags ? 0 : SKF_V6ONLY; s->tos = IP_PREC_INTERNET_CONTROL; s->rbsize = BGP_RX_BUFFER_SIZE; s->tbsize = BGP_TX_BUFFER_SIZE; s->rx_hook = bgp_incoming_connection; s->err_hook = bgp_listen_sock_err; if (sk_open(s) < 0) { log(L_ERR "BGP: Unable to open listening socket"); rfree(s); return NULL; } return s; } static void bgp_start_neighbor(struct bgp_proto *p) { /* Called only for single-hop BGP sessions */ /* Remove this ? */ if (ipa_zero(p->source_addr)) p->source_addr = p->neigh->iface->addr->ip; #ifdef IPV6 { struct ifa *a; p->local_link = IPA_NONE; WALK_LIST(a, p->neigh->iface->addrs) if (a->scope == SCOPE_LINK) { p->local_link = a->ip; break; } if (! ipa_nonzero(p->local_link)) log(L_WARN "%s: Missing link local address on interface %s", p->p.name, p->neigh->iface->name); DBG("BGP: Selected link-level address %I\n", p->local_link); } #endif bgp_initiate(p); } static void bgp_neigh_notify(neighbor *n) { struct bgp_proto *p = (struct bgp_proto *) n->proto; if (n->scope > 0) { if ((p->p.proto_state == PS_START) && (p->start_state == BSS_PREPARE)) { BGP_TRACE(D_EVENTS, "Neighbor found"); bgp_start_neighbor(p); } } else { if ((p->p.proto_state == PS_START) || (p->p.proto_state == PS_UP)) { BGP_TRACE(D_EVENTS, "Neighbor lost"); bgp_store_error(p, NULL, BE_MISC, BEM_NEIGHBOR_LOST); bgp_stop(p, 0); } } } static int bgp_reload_routes(struct proto *P) { struct bgp_proto *p = (struct bgp_proto *) P; if (!p->conn || !p->conn->peer_refresh_support) return 0; bgp_schedule_packet(p->conn, PKT_ROUTE_REFRESH); return 1; } static void bgp_start_locked(struct object_lock *lock) { struct bgp_proto *p = lock->data; struct bgp_config *cf = p->cf; if (p->p.proto_state != PS_START) { DBG("BGP: Got lock in different state %d\n", p->p.proto_state); return; } DBG("BGP: Got lock\n"); if (cf->multihop) { /* Multi-hop sessions do not use neighbor entries */ bgp_initiate(p); return; } p->neigh = neigh_find2(&p->p, &cf->remote_ip, cf->iface, NEF_STICKY); if (!p->neigh || (p->neigh->scope == SCOPE_HOST)) { log(L_ERR "%s: Invalid remote address %I%J", p->p.name, cf->remote_ip, cf->iface); /* As we do not start yet, we can just disable protocol */ p->p.disabled = 1; bgp_store_error(p, NULL, BE_MISC, BEM_INVALID_NEXT_HOP); proto_notify_state(&p->p, PS_DOWN); return; } if (p->neigh->scope > 0) bgp_start_neighbor(p); else BGP_TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", cf->remote_ip, cf->iface); } static int bgp_start(struct proto *P) { struct bgp_proto *p = (struct bgp_proto *) P; struct object_lock *lock; DBG("BGP: Startup.\n"); p->start_state = BSS_PREPARE; p->outgoing_conn.state = BS_IDLE; p->incoming_conn.state = BS_IDLE; p->neigh = NULL; rt_lock_table(p->igp_table); p->event = ev_new(p->p.pool); p->event->hook = bgp_decision; p->event->data = p; p->startup_timer = tm_new(p->p.pool); p->startup_timer->hook = bgp_startup_timeout; p->startup_timer->data = p; p->local_id = proto_get_router_id(P->cf); if (p->rr_client) p->rr_cluster_id = p->cf->rr_cluster_id ? p->cf->rr_cluster_id : p->local_id; p->remote_id = 0; p->source_addr = p->cf->source_addr; /* * Before attempting to create the connection, we need to lock the * port, so that are sure we're the only instance attempting to talk * with that neighbor. */ lock = p->lock = olock_new(P->pool); lock->addr = p->cf->remote_ip; lock->iface = p->cf->iface; lock->type = OBJLOCK_TCP; lock->port = BGP_PORT; lock->iface = NULL; lock->hook = bgp_start_locked; lock->data = p; olock_acquire(lock); return PS_START; } static int bgp_shutdown(struct proto *P) { struct bgp_proto *p = (struct bgp_proto *) P; unsigned subcode; BGP_TRACE(D_EVENTS, "Shutdown requested"); bgp_store_error(p, NULL, BE_MAN_DOWN, 0); if (P->reconfiguring) { if (P->cf_new) subcode = 6; // Errcode 6, 6 - other configuration change else subcode = 3; // Errcode 6, 3 - peer de-configured } else subcode = 2; // Errcode 6, 2 - administrative shutdown p->startup_delay = 0; bgp_stop(p, subcode); return p->p.proto_state; } static void bgp_cleanup(struct proto *P) { struct bgp_proto *p = (struct bgp_proto *) P; rt_unlock_table(p->igp_table); } static rtable * get_igp_table(struct bgp_config *cf) { return cf->igp_table ? cf->igp_table->table : cf->c.table->table; } static struct proto * bgp_init(struct proto_config *C) { struct bgp_config *c = (struct bgp_config *) C; struct proto *P = proto_new(C, sizeof(struct bgp_proto)); struct bgp_proto *p = (struct bgp_proto *) P; P->accept_ra_types = c->secondary ? RA_ACCEPTED : RA_OPTIMAL; P->rt_notify = bgp_rt_notify; P->rte_better = bgp_rte_better; P->import_control = bgp_import_control; P->neigh_notify = bgp_neigh_notify; P->reload_routes = bgp_reload_routes; if (c->deterministic_med) P->rte_recalculate = bgp_rte_recalculate; p->cf = c; p->local_as = c->local_as; p->remote_as = c->remote_as; p->is_internal = (c->local_as == c->remote_as); p->rs_client = c->rs_client; p->rr_client = c->rr_client; p->igp_table = get_igp_table(c); return P; } void bgp_check_config(struct bgp_config *c) { int internal = (c->local_as == c->remote_as); /* Do not check templates at all */ if (c->c.class == SYM_TEMPLATE) return; if (!c->local_as) cf_error("Local AS number must be set"); if (!c->remote_as) cf_error("Neighbor must be configured"); if (!(c->capabilities && c->enable_as4) && (c->remote_as > 0xFFFF)) cf_error("Neighbor AS number out of range (AS4 not available)"); if (!internal && c->rr_client) cf_error("Only internal neighbor can be RR client"); if (internal && c->rs_client) cf_error("Only external neighbor can be RS client"); if (c->multihop && (c->gw_mode == GW_DIRECT)) cf_error("Multihop BGP cannot use direct gateway mode"); if (c->multihop && (ipa_has_link_scope(c->remote_ip) || ipa_has_link_scope(c->source_addr))) cf_error("Multihop BGP cannot be used with link-local addresses"); /* Different default based on rs_client */ if (!c->missing_lladdr) c->missing_lladdr = c->rs_client ? MLL_IGNORE : MLL_SELF; /* Different default for gw_mode */ if (!c->gw_mode) c->gw_mode = (c->multihop || internal) ? GW_RECURSIVE : GW_DIRECT; if ((c->gw_mode == GW_RECURSIVE) && c->c.table->sorted) cf_error("BGP in recursive mode prohibits sorted table"); if (c->deterministic_med && c->c.table->sorted) cf_error("BGP with deterministic MED prohibits sorted table"); if (c->secondary && !c->c.table->sorted) cf_error("BGP with secondary option requires sorted table"); } static int bgp_reconfigure(struct proto *P, struct proto_config *C) { struct bgp_config *new = (struct bgp_config *) C; struct bgp_proto *p = (struct bgp_proto *) P; struct bgp_config *old = p->cf; int same = !memcmp(((byte *) old) + sizeof(struct proto_config), ((byte *) new) + sizeof(struct proto_config), // password item is last and must be checked separately OFFSETOF(struct bgp_config, password) - sizeof(struct proto_config)) && ((!old->password && !new->password) || (old->password && new->password && !strcmp(old->password, new->password))) && (get_igp_table(old) == get_igp_table(new)); /* We should update our copy of configuration ptr as old configuration will be freed */ if (same) p->cf = new; return same; } static void bgp_copy_config(struct proto_config *dest, struct proto_config *src) { /* Just a shallow copy */ proto_copy_rest(dest, src, sizeof(struct bgp_config)); } /** * bgp_error - report a protocol error * @c: connection * @code: error code (according to the RFC) * @subcode: error sub-code * @data: data to be passed in the Notification message * @len: length of the data * * bgp_error() sends a notification packet to tell the other side that a protocol * error has occurred (including the data considered erroneous if possible) and * closes the connection. */ void bgp_error(struct bgp_conn *c, unsigned code, unsigned subcode, byte *data, int len) { struct bgp_proto *p = c->bgp; if (c->state == BS_CLOSE) return; bgp_log_error(p, BE_BGP_TX, "Error", code, subcode, data, (len > 0) ? len : -len); bgp_store_error(p, c, BE_BGP_TX, (code << 16) | subcode); bgp_conn_enter_close_state(c); c->notify_code = code; c->notify_subcode = subcode; c->notify_data = data; c->notify_size = (len > 0) ? len : 0; bgp_schedule_packet(c, PKT_NOTIFICATION); if (code != 6) { bgp_update_startup_delay(p); bgp_stop(p, 0); } } /** * bgp_store_error - store last error for status report * @p: BGP instance * @c: connection * @class: error class (BE_xxx constants) * @code: error code (class specific) * * bgp_store_error() decides whether given error is interesting enough * and store that error to last_error variables of @p */ void bgp_store_error(struct bgp_proto *p, struct bgp_conn *c, u8 class, u32 code) { /* During PS_UP, we ignore errors on secondary connection */ if ((p->p.proto_state == PS_UP) && c && (c != p->conn)) return; /* During PS_STOP, we ignore any errors, as we want to report * the error that caused transition to PS_STOP */ if (p->p.proto_state == PS_STOP) return; p->last_error_class = class; p->last_error_code = code; } static char *bgp_state_names[] = { "Idle", "Connect", "Active", "OpenSent", "OpenConfirm", "Established", "Close" }; static char *bgp_err_classes[] = { "", "Error: ", "Socket: ", "Received: ", "BGP Error: ", "Automatic shutdown: ", ""}; static char *bgp_misc_errors[] = { "", "Neighbor lost", "Invalid next hop", "Kernel MD5 auth failed", "No listening socket" }; static char *bgp_auto_errors[] = { "", "Route limit exceeded"}; static const char * bgp_last_errmsg(struct bgp_proto *p) { switch (p->last_error_class) { case BE_MISC: return bgp_misc_errors[p->last_error_code]; case BE_SOCKET: return (p->last_error_code == 0) ? "Connection closed" : strerror(p->last_error_code); case BE_BGP_RX: case BE_BGP_TX: return bgp_error_dsc(p->last_error_code >> 16, p->last_error_code & 0xFF); case BE_AUTO_DOWN: return bgp_auto_errors[p->last_error_code]; default: return ""; } } static const char * bgp_state_dsc(struct bgp_proto *p) { if (p->p.proto_state == PS_DOWN) return "Down"; int state = MAX(p->incoming_conn.state, p->outgoing_conn.state); if ((state == BS_IDLE) && (p->start_state >= BSS_CONNECT) && p->cf->passive) return "Passive"; return bgp_state_names[state]; } static void bgp_get_status(struct proto *P, byte *buf) { struct bgp_proto *p = (struct bgp_proto *) P; const char *err1 = bgp_err_classes[p->last_error_class]; const char *err2 = bgp_last_errmsg(p); if (P->proto_state == PS_DOWN) bsprintf(buf, "%s%s", err1, err2); else bsprintf(buf, "%-14s%s%s", bgp_state_dsc(p), err1, err2); } static inline bird_clock_t tm_remains(timer *t) { return t->expires ? t->expires - now : 0; } static void bgp_show_proto_info(struct proto *P) { struct bgp_proto *p = (struct bgp_proto *) P; struct bgp_conn *c = p->conn; proto_show_basic_info(P); cli_msg(-1006, " BGP state: %s", bgp_state_dsc(p)); cli_msg(-1006, " Neighbor address: %I%J", p->cf->remote_ip, p->cf->iface); cli_msg(-1006, " Neighbor AS: %u", p->remote_as); if (P->proto_state == PS_START) { struct bgp_conn *oc = &p->outgoing_conn; if ((p->start_state < BSS_CONNECT) && (p->startup_timer->expires)) cli_msg(-1006, " Error wait: %d/%d", p->startup_timer->expires - now, p->startup_delay); if ((oc->state == BS_ACTIVE) && (oc->connect_retry_timer->expires)) cli_msg(-1006, " Start delay: %d/%d", oc->connect_retry_timer->expires - now, p->cf->start_delay_time); } else if (P->proto_state == PS_UP) { cli_msg(-1006, " Neighbor ID: %R", p->remote_id); cli_msg(-1006, " Neighbor caps: %s%s", c->peer_refresh_support ? " refresh" : "", c->peer_as4_support ? " AS4" : ""); cli_msg(-1006, " Session: %s%s%s%s%s", p->is_internal ? "internal" : "external", p->cf->multihop ? " multihop" : "", p->rr_client ? " route-reflector" : "", p->rs_client ? " route-server" : "", p->as4_session ? " AS4" : ""); cli_msg(-1006, " Source address: %I", p->source_addr); if (p->cf->route_limit) cli_msg(-1006, " Route limit: %d/%d", p->p.stats.imp_routes, p->cf->route_limit); cli_msg(-1006, " Hold timer: %d/%d", tm_remains(c->hold_timer), c->hold_time); cli_msg(-1006, " Keepalive timer: %d/%d", tm_remains(c->keepalive_timer), c->keepalive_time); } if ((p->last_error_class != BE_NONE) && (p->last_error_class != BE_MAN_DOWN)) { const char *err1 = bgp_err_classes[p->last_error_class]; const char *err2 = bgp_last_errmsg(p); cli_msg(-1006, " Last error: %s%s", err1, err2); } } struct protocol proto_bgp = { name: "BGP", template: "bgp%d", attr_class: EAP_BGP, preference: DEF_PREF_BGP, init: bgp_init, start: bgp_start, shutdown: bgp_shutdown, cleanup: bgp_cleanup, reconfigure: bgp_reconfigure, copy_config: bgp_copy_config, get_status: bgp_get_status, get_attr: bgp_get_attr, get_route_info: bgp_get_route_info, show_proto_info: bgp_show_proto_info };