/* * BIRD -- The Babel protocol * * Copyright (c) 2015--2016 Toke Hoiland-Jorgensen * * Can be freely distributed and used under the terms of the GNU GPL. * * This file contains the main routines for handling and sending TLVs, as * well as timers and interaction with the nest. */ /** * DOC: The Babel protocol * * Babel (RFC6126) is a loop-avoiding distance-vector routing protocol that is * robust and efficient both in ordinary wired networks and in wireless mesh * networks. * * The Babel protocol keeps state for each neighbour in a &babel_neighbor * struct, tracking received Hello and I Heard You (IHU) messages. A * &babel_interface struct keeps hello and update times for each interface, and * a separate hello seqno is maintained for each interface. * * For each prefix, Babel keeps track of both the possible routes (with next hop * and router IDs), as well as the feasibility distance for each prefix and * router id. The prefix itself is tracked in a &babel_entry struct, while the * possible routes for the prefix are tracked as &babel_route entries and the * feasibility distance is maintained through &babel_source structures. * * The main route selection is done in babel_select_route(). This is called when * an entry is updated by receiving updates from the network or when modified by * internal timers. It performs feasibility checks on the available routes for * the prefix and selects the one with the lowest metric to be announced to the * core. */ #include #include "babel.h" #define OUR_ROUTE(r) (r->neigh == NULL) /* * Is one number greater or equal than another mod 2^16? This is based on the * definition of serial number space in RFC 1982. Note that arguments are of * uint type to avoid integer promotion to signed integer. */ static inline int ge_mod64k(uint a, uint b) { return (u16)(a - b) < 0x8000; } static void babel_dump_entry(struct babel_entry *e); static void babel_dump_route(struct babel_route *r); static void babel_select_route(struct babel_entry *e); static void babel_send_route_request(struct babel_entry *e, struct babel_neighbor *n); static void babel_send_wildcard_request(struct babel_iface *ifa); static int babel_cache_seqno_request(struct babel_proto *p, ip_addr prefix, u8 plen, u64 router_id, u16 seqno); static void babel_trigger_iface_update(struct babel_iface *ifa); static void babel_trigger_update(struct babel_proto *p); static void babel_send_seqno_request(struct babel_entry *e); static inline void babel_kick_timer(struct babel_proto *p); static inline void babel_iface_kick_timer(struct babel_iface *ifa); /* * Functions to maintain data structures */ static void babel_init_entry(struct fib_node *n) { struct babel_entry *e = (void *) n; e->proto = NULL; e->selected_in = NULL; e->selected_out = NULL; e->updated = now; init_list(&e->sources); init_list(&e->routes); } static inline struct babel_entry * babel_find_entry(struct babel_proto *p, ip_addr prefix, u8 plen) { return fib_find(&p->rtable, &prefix, plen); } static struct babel_entry * babel_get_entry(struct babel_proto *p, ip_addr prefix, u8 plen) { struct babel_entry *e = fib_get(&p->rtable, &prefix, plen); e->proto = p; return e; } static struct babel_source * babel_find_source(struct babel_entry *e, u64 router_id) { struct babel_source *s; WALK_LIST(s, e->sources) if (s->router_id == router_id) return s; return NULL; } static struct babel_source * babel_get_source(struct babel_entry *e, u64 router_id) { struct babel_proto *p = e->proto; struct babel_source *s = babel_find_source(e, router_id); if (s) return s; s = sl_alloc(p->source_slab); s->router_id = router_id; s->expires = now + BABEL_GARBAGE_INTERVAL; s->seqno = 0; s->metric = BABEL_INFINITY; add_tail(&e->sources, NODE s); return s; } static void babel_expire_sources(struct babel_entry *e) { struct babel_proto *p = e->proto; struct babel_source *n, *nx; WALK_LIST_DELSAFE(n, nx, e->sources) { if (n->expires && n->expires <= now) { rem_node(NODE n); sl_free(p->source_slab, n); } } } static struct babel_route * babel_find_route(struct babel_entry *e, struct babel_neighbor *n) { struct babel_route *r; WALK_LIST(r, e->routes) if (r->neigh == n) return r; return NULL; } static struct babel_route * babel_get_route(struct babel_entry *e, struct babel_neighbor *nbr) { struct babel_proto *p = e->proto; struct babel_route *r = babel_find_route(e, nbr); if (r) return r; r = sl_alloc(p->route_slab); memset(r, 0, sizeof(*r)); r->e = e; add_tail(&e->routes, NODE r); if (nbr) { r->neigh = nbr; r->expires = now + BABEL_GARBAGE_INTERVAL; add_tail(&nbr->routes, NODE &r->neigh_route); } return r; } static void babel_flush_route(struct babel_route *r) { struct babel_proto *p = r->e->proto; DBG("Babel: Flush route %I/%d router_id %lR neigh %I\n", r->e->n.prefix, r->e->n.pxlen, r->router_id, r->neigh ? r->neigh->addr : IPA_NONE); rem_node(NODE r); if (r->neigh) rem_node(&r->neigh_route); if (r->e->selected_in == r) r->e->selected_in = NULL; if (r->e->selected_out == r) r->e->selected_out = NULL; sl_free(p->route_slab, r); } static void babel_expire_route(struct babel_route *r) { struct babel_proto *p = r->e->proto; struct babel_entry *e = r->e; TRACE(D_EVENTS, "Route expiry timer for %I/%d router-id %lR fired", e->n.prefix, e->n.pxlen, r->router_id); if (r->metric < BABEL_INFINITY) { r->metric = BABEL_INFINITY; r->expires = now + r->expiry_interval; } else { babel_flush_route(r); } } static void babel_refresh_route(struct babel_route *r) { if (!OUR_ROUTE(r) && (r == r->e->selected_in)) babel_send_route_request(r->e, r->neigh); r->refresh_time = 0; } static void babel_expire_routes(struct babel_proto *p) { struct babel_entry *e; struct babel_route *r, *rx; struct fib_iterator fit; FIB_ITERATE_INIT(&fit, &p->rtable); loop: FIB_ITERATE_START(&p->rtable, &fit, n) { e = (struct babel_entry *) n; int changed = 0; WALK_LIST_DELSAFE(r, rx, e->routes) { if (r->refresh_time && r->refresh_time <= now) babel_refresh_route(r); if (r->expires && r->expires <= now) { babel_expire_route(r); changed = 1; } } if (changed) { /* * We have to restart the iteration because there may be a cascade of * synchronous events babel_select_route() -> nest table change -> * babel_rt_notify() -> p->rtable change, invalidating hidden variables. */ FIB_ITERATE_PUT(&fit, n); babel_select_route(e); goto loop; } babel_expire_sources(e); /* Remove empty entries */ if (EMPTY_LIST(e->sources) && EMPTY_LIST(e->routes)) { FIB_ITERATE_PUT(&fit, n); fib_delete(&p->rtable, e); goto loop; } } FIB_ITERATE_END(n); } static struct babel_neighbor * babel_find_neighbor(struct babel_iface *ifa, ip_addr addr) { struct babel_neighbor *nbr; WALK_LIST(nbr, ifa->neigh_list) if (ipa_equal(nbr->addr, addr)) return nbr; return NULL; } static struct babel_neighbor * babel_get_neighbor(struct babel_iface *ifa, ip_addr addr) { struct babel_neighbor *nbr = babel_find_neighbor(ifa, addr); if (nbr) return nbr; nbr = mb_allocz(ifa->pool, sizeof(struct babel_neighbor)); nbr->ifa = ifa; nbr->addr = addr; nbr->txcost = BABEL_INFINITY; init_list(&nbr->routes); add_tail(&ifa->neigh_list, NODE nbr); return nbr; } static void babel_flush_neighbor(struct babel_neighbor *nbr) { struct babel_proto *p = nbr->ifa->proto; node *n; TRACE(D_EVENTS, "Flushing neighbor %I", nbr->addr); WALK_LIST_FIRST(n, nbr->routes) { struct babel_route *r = SKIP_BACK(struct babel_route, neigh_route, n); struct babel_entry *e = r->e; int selected = (r == e->selected_in); babel_flush_route(r); if (selected) babel_select_route(e); } rem_node(NODE nbr); mb_free(nbr); } static void babel_expire_ihu(struct babel_neighbor *nbr) { nbr->txcost = BABEL_INFINITY; } static void babel_expire_hello(struct babel_neighbor *nbr) { nbr->hello_map <<= 1; if (nbr->hello_cnt < 16) nbr->hello_cnt++; if (!nbr->hello_map) babel_flush_neighbor(nbr); } static void babel_expire_neighbors(struct babel_proto *p) { struct babel_iface *ifa; struct babel_neighbor *nbr, *nbx; WALK_LIST(ifa, p->interfaces) { WALK_LIST_DELSAFE(nbr, nbx, ifa->neigh_list) { if (nbr->ihu_expiry && nbr->ihu_expiry <= now) babel_expire_ihu(nbr); if (nbr->hello_expiry && nbr->hello_expiry <= now) babel_expire_hello(nbr); } } } /* * Best route selection */ /* * From the RFC (section 3.5.1): * * a route advertisement carrying the quintuple (prefix, plen, router-id, seqno, * metric) is feasible if one of the following conditions holds: * * - metric is infinite; or * * - no entry exists in the source table indexed by (id, prefix, plen); or * * - an entry (prefix, plen, router-id, seqno', metric') exists in the source * table, and either * - seqno' < seqno or * - seqno = seqno' and metric < metric'. */ static inline int babel_is_feasible(struct babel_source *s, u16 seqno, u16 metric) { return !s || (metric == BABEL_INFINITY) || (seqno > s->seqno) || ((seqno == s->seqno) && (metric < s->metric)); } static u16 babel_compute_rxcost(struct babel_neighbor *n) { struct babel_iface *ifa = n->ifa; u8 cnt, missed; u16 map=n->hello_map; if (!map) return BABEL_INFINITY; cnt = u32_popcount(map); // number of bits set missed = n->hello_cnt-cnt; if (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS) { /* ETX - Appendix 2.2 in the RFC. beta = prob. of successful transmission. rxcost = BABEL_RXCOST_WIRELESS/beta Since: beta = 1-missed/n->hello_cnt = cnt/n->hello_cnt Then: rxcost = BABEL_RXCOST_WIRELESS * n->hello_cnt / cnt */ if (!cnt) return BABEL_INFINITY; return BABEL_RXCOST_WIRELESS * n->hello_cnt / cnt; } else { /* k-out-of-j selection - Appendix 2.1 in the RFC. */ DBG("Babel: Missed %d hellos from %I\n", missed, n->addr); /* Link is bad if more than half the expected hellos were lost */ return (missed > n->hello_cnt/2) ? BABEL_INFINITY : ifa->cf->rxcost; } } static u16 babel_compute_cost(struct babel_neighbor *n) { struct babel_iface *ifa = n->ifa; u16 rxcost = babel_compute_rxcost(n); if (rxcost == BABEL_INFINITY) return rxcost; else if (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS) { /* ETX - Appendix 2.2 in the RFC */ return (MAX(n->txcost, BABEL_RXCOST_WIRELESS) * rxcost)/BABEL_RXCOST_WIRELESS; } else { /* k-out-of-j selection - Appendix 2.1 in the RFC. */ return n->txcost; } } /* Simple additive metric - Appendix 3.1 in the RFC */ static u16 babel_compute_metric(struct babel_neighbor *n, uint metric) { metric += babel_compute_cost(n); return MIN(metric, BABEL_INFINITY); } /** * babel_announce_rte - announce selected route to the core * @p: Babel protocol instance * @e: Babel route entry to announce * * This function announces a Babel entry to the core if it has a selected * incoming path, and retracts it otherwise. If the selected entry has infinite * metric, the route is announced as unreachable. */ static void babel_announce_rte(struct babel_proto *p, struct babel_entry *e) { struct babel_route *r = e->selected_in; if (r) { net *n = net_get(p->p.table, e->n.prefix, e->n.pxlen); rta A = { .src = p->p.main_source, .source = RTS_BABEL, .scope = SCOPE_UNIVERSE, .cast = RTC_UNICAST, .dest = r->metric == BABEL_INFINITY ? RTD_UNREACHABLE : RTD_ROUTER, .flags = 0, .from = r->neigh->addr, .iface = r->neigh->ifa->iface, }; if (r->metric < BABEL_INFINITY) A.gw = r->next_hop; rta *a = rta_lookup(&A); rte *rte = rte_get_temp(a); rte->u.babel.metric = r->metric; rte->u.babel.router_id = r->router_id; rte->net = n; rte->pflags = 0; rte_update(&p->p, n, rte); } else { /* Retraction */ net *n = net_find(p->p.table, e->n.prefix, e->n.pxlen); rte_update(&p->p, n, NULL); } } /** * babel_select_route - select best route for given route entry * @e: Babel entry to select the best route for * * Select the best feasible route for a given prefix among the routes received * from peers, and propagate it to the nest. This just selects the feasible * route with the lowest metric. * * If no feasible route is available for a prefix that previously had a route * selected, a seqno request is sent to try to get a valid route. In the * meantime, the route is marked as infeasible in the nest (to blackhole packets * going to it, as per the RFC). * * If no feasible route is available, and no previous route is selected, the * route is removed from the nest entirely. */ static void babel_select_route(struct babel_entry *e) { struct babel_proto *p = e->proto; struct babel_route *r, *cur = e->selected_in; /* try to find the best feasible route */ WALK_LIST(r, e->routes) if (!OUR_ROUTE(r) && /* prevent propagating our own routes back to core */ (!cur || r->metric < cur->metric) && babel_is_feasible(babel_find_source(e, r->router_id), r->seqno, r->advert_metric)) cur = r; if (cur && !OUR_ROUTE(cur) && ((!e->selected_in && cur->metric < BABEL_INFINITY) || (e->selected_in && cur->metric < e->selected_in->metric))) { TRACE(D_EVENTS, "Picked new route for prefix %I/%d: router id %lR metric %d", e->n.prefix, e->n.pxlen, cur->router_id, cur->metric); e->selected_in = cur; e->updated = now; babel_announce_rte(p, e); } else if (!cur || cur->metric == BABEL_INFINITY) { /* Couldn't find a feasible route. If we have a selected route, that means it just became infeasible; so set it's metric to infinite and install it (as unreachable), then send a seqno request. babel_build_rte() will set the unreachable flag if the metric is BABEL_INFINITY.*/ if (e->selected_in) { TRACE(D_EVENTS, "Lost feasible route for prefix %I/%d", e->n.prefix, e->n.pxlen); e->selected_in->metric = BABEL_INFINITY; e->updated = now; babel_send_seqno_request(e); babel_announce_rte(p, e); } else { /* No route currently selected, and no new one selected; this means we don't have a route to this destination anymore (and were probably called from an expiry timer). Remove the route from the nest. */ TRACE(D_EVENTS, "Flushing route for prefix %I/%d", e->n.prefix, e->n.pxlen); e->selected_in = NULL; e->updated = now; babel_announce_rte(p, e); } } } /* * Functions to send replies */ static void babel_send_ack(struct babel_iface *ifa, ip_addr dest, u16 nonce) { struct babel_proto *p = ifa->proto; union babel_msg msg = {}; TRACE(D_PACKETS, "Sending ACK to %I with nonce %d", dest, nonce); msg.type = BABEL_TLV_ACK; msg.ack.nonce = nonce; babel_send_unicast(&msg, ifa, dest); } static void babel_build_ihu(union babel_msg *msg, struct babel_iface *ifa, struct babel_neighbor *n) { struct babel_proto *p = ifa->proto; msg->type = BABEL_TLV_IHU; msg->ihu.addr = n->addr; msg->ihu.rxcost = babel_compute_rxcost(n); msg->ihu.interval = ifa->cf->ihu_interval; TRACE(D_PACKETS, "Sending IHU for %I with rxcost %d interval %d", msg->ihu.addr, msg->ihu.rxcost, msg->ihu.interval); } static void babel_send_ihu(struct babel_iface *ifa, struct babel_neighbor *n) { union babel_msg msg = {}; babel_build_ihu(&msg, ifa, n); babel_send_unicast(&msg, ifa, n->addr); } static void babel_send_ihus(struct babel_iface *ifa) { struct babel_neighbor *n; WALK_LIST(n, ifa->neigh_list) { union babel_msg msg = {}; babel_build_ihu(&msg, ifa, n); babel_enqueue(&msg, ifa); } } static void babel_send_hello(struct babel_iface *ifa, u8 send_ihu) { struct babel_proto *p = ifa->proto; union babel_msg msg = {}; msg.type = BABEL_TLV_HELLO; msg.hello.seqno = ifa->hello_seqno++; msg.hello.interval = ifa->cf->hello_interval; TRACE(D_PACKETS, "Sending hello on %s with seqno %d interval %d", ifa->ifname, msg.hello.seqno, msg.hello.interval); babel_enqueue(&msg, ifa); if (send_ihu) babel_send_ihus(ifa); } static void babel_send_route_request(struct babel_entry *e, struct babel_neighbor *n) { struct babel_proto *p = e->proto; struct babel_iface *ifa = n->ifa; union babel_msg msg = {}; TRACE(D_PACKETS, "Sending route request for %I/%d to %I", e->n.prefix, e->n.pxlen, n->addr); msg.type = BABEL_TLV_ROUTE_REQUEST; msg.route_request.prefix = e->n.prefix; msg.route_request.plen = e->n.pxlen; babel_send_unicast(&msg, ifa, n->addr); } static void babel_send_wildcard_request(struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; union babel_msg msg = {}; TRACE(D_PACKETS, "Sending wildcard route request on %s", ifa->ifname); msg.type = BABEL_TLV_ROUTE_REQUEST; msg.route_request.full = 1; babel_enqueue(&msg, ifa); } static void babel_send_seqno_request(struct babel_entry *e) { struct babel_proto *p = e->proto; struct babel_route *r = e->selected_in; struct babel_iface *ifa = NULL; struct babel_source *s = NULL; union babel_msg msg = {}; s = babel_find_source(e, r->router_id); if (!s || !babel_cache_seqno_request(p, e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1)) return; TRACE(D_PACKETS, "Sending seqno request for %I/%d router-id %lR seqno %d", e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1); msg.type = BABEL_TLV_SEQNO_REQUEST; msg.seqno_request.plen = e->n.pxlen; msg.seqno_request.seqno = s->seqno + 1; msg.seqno_request.hop_count = BABEL_INITIAL_HOP_COUNT; msg.seqno_request.router_id = r->router_id; msg.seqno_request.prefix = e->n.prefix; WALK_LIST(ifa, p->interfaces) babel_enqueue(&msg, ifa); } static void babel_unicast_seqno_request(struct babel_route *r) { struct babel_entry *e = r->e; struct babel_proto *p = e->proto; struct babel_iface *ifa = r->neigh->ifa; struct babel_source *s = NULL; union babel_msg msg = {}; s = babel_find_source(e, r->router_id); if (!s || !babel_cache_seqno_request(p, e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1)) return; TRACE(D_PACKETS, "Sending seqno request for %I/%d router-id %lR seqno %d", e->n.prefix, e->n.pxlen, r->router_id, s->seqno + 1); msg.type = BABEL_TLV_SEQNO_REQUEST; msg.seqno_request.plen = e->n.pxlen; msg.seqno_request.seqno = s->seqno + 1; msg.seqno_request.hop_count = BABEL_INITIAL_HOP_COUNT; msg.seqno_request.router_id = r->router_id; msg.seqno_request.prefix = e->n.prefix; babel_send_unicast(&msg, ifa, r->neigh->addr); } /** * babel_send_update - send route table updates * @ifa: Interface to transmit on * @changed: Only send entries changed since this time * * This function produces update TLVs for all entries changed since the time * indicated by the &changed parameter and queues them for transmission on the * selected interface. During the process, the feasibility distance for each * transmitted entry is updated. */ static void babel_send_update(struct babel_iface *ifa, bird_clock_t changed) { struct babel_proto *p = ifa->proto; FIB_WALK(&p->rtable, n) { struct babel_entry *e = (void *) n; struct babel_route *r = e->selected_out; if (!r) continue; /* Our own seqno might have changed, in which case we update the routes we originate. */ if ((r->router_id == p->router_id) && (r->seqno < p->update_seqno)) { r->seqno = p->update_seqno; e->updated = now; } /* Skip routes that weren't updated since 'changed' time */ if (e->updated < changed) continue; TRACE(D_PACKETS, "Sending update for %I/%d router-id %lR seqno %d metric %d", e->n.prefix, e->n.pxlen, r->router_id, r->seqno, r->metric); union babel_msg msg = {}; msg.type = BABEL_TLV_UPDATE; msg.update.plen = e->n.pxlen; msg.update.interval = ifa->cf->update_interval; msg.update.seqno = r->seqno; msg.update.metric = r->metric; msg.update.prefix = e->n.prefix; msg.update.router_id = r->router_id; /* Update feasibility distance */ struct babel_source *s = babel_get_source(e, r->router_id); s->expires = now + BABEL_GARBAGE_INTERVAL; if ((msg.update.seqno > s->seqno) || ((msg.update.seqno == s->seqno) && (msg.update.metric < s->metric))) { s->seqno = msg.update.seqno; s->metric = msg.update.metric; } babel_enqueue(&msg, ifa); } FIB_WALK_END; } static void babel_trigger_iface_update(struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; /* Interface not active or already scheduled */ if (!ifa->up || ifa->want_triggered) return; TRACE(D_EVENTS, "Scheduling triggered updates for %s seqno %d", ifa->iface->name, p->update_seqno); ifa->want_triggered = now; babel_iface_kick_timer(ifa); } /* Sends and update on all interfaces. */ static void babel_trigger_update(struct babel_proto *p) { if (p->triggered) return; struct babel_iface *ifa; WALK_LIST(ifa, p->interfaces) babel_trigger_iface_update(ifa); p->triggered = 1; } /* A retraction is an update with an infinite metric */ static void babel_send_retraction(struct babel_iface *ifa, ip_addr prefix, int plen) { struct babel_proto *p = ifa->proto; union babel_msg msg = {}; TRACE(D_PACKETS, "Sending retraction for %I/%d seqno %d", prefix, plen, p->update_seqno); msg.type = BABEL_TLV_UPDATE; msg.update.plen = plen; msg.update.interval = ifa->cf->update_interval; msg.update.seqno = p->update_seqno; msg.update.metric = BABEL_INFINITY; msg.update.prefix = prefix; babel_enqueue(&msg, ifa); } static void babel_send_wildcard_retraction(struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; union babel_msg msg = {}; TRACE(D_PACKETS, "Sending wildcard retraction on %s", ifa->ifname); msg.type = BABEL_TLV_UPDATE; msg.update.wildcard = 1; msg.update.interval = ifa->cf->update_interval; msg.update.seqno = p->update_seqno; msg.update.metric = BABEL_INFINITY; babel_enqueue(&msg, ifa); } /* * TLV handler helpers */ /* Update hello history according to Appendix A1 of the RFC */ static void babel_update_hello_history(struct babel_neighbor *n, u16 seqno, u16 interval) { /* * Compute the difference between expected and received seqno (modulo 2^16). * If the expected and received seqnos are within 16 of each other, the modular * difference is going to be less than 16 for one of the directions. Otherwise, * the values differ too much, so just reset the state. */ u16 delta = ((uint) seqno - (uint) n->next_hello_seqno); if (delta == 0) { /* Do nothing */ } else if (delta <= 16) { /* Sending node decreased interval; fast-forward */ n->hello_map <<= delta; n->hello_cnt = MIN(n->hello_cnt + delta, 16); } else if (delta >= 0xfff0) { u8 diff = (0xffff - delta); /* Sending node increased interval; undo history */ n->hello_map >>= diff; n->hello_cnt = (diff < n->hello_cnt) ? n->hello_cnt - diff : 0; } else { /* Note state reset - flush entries */ n->hello_map = n->hello_cnt = 0; } /* Current entry */ n->hello_map = (n->hello_map << 1) | 1; n->next_hello_seqno = seqno+1; if (n->hello_cnt < 16) n->hello_cnt++; n->hello_expiry = now + BABEL_HELLO_EXPIRY_FACTOR(interval); } static void babel_expire_seqno_requests(struct babel_proto *p) { struct babel_seqno_request *n, *nx; WALK_LIST_DELSAFE(n, nx, p->seqno_cache) { if ((n->updated + BABEL_SEQNO_REQUEST_EXPIRY) <= now) { rem_node(NODE n); sl_free(p->seqno_slab, n); } } } /* * Checks the seqno request cache for a matching request and returns failure if * found. Otherwise, a new entry is stored in the cache. */ static int babel_cache_seqno_request(struct babel_proto *p, ip_addr prefix, u8 plen, u64 router_id, u16 seqno) { struct babel_seqno_request *r; WALK_LIST(r, p->seqno_cache) { if (ipa_equal(r->prefix, prefix) && (r->plen == plen) && (r->router_id == router_id) && (r->seqno == seqno)) return 0; } /* no entries found */ r = sl_alloc(p->seqno_slab); r->prefix = prefix; r->plen = plen; r->router_id = router_id; r->seqno = seqno; r->updated = now; add_tail(&p->seqno_cache, NODE r); return 1; } static void babel_forward_seqno_request(struct babel_entry *e, struct babel_msg_seqno_request *in, ip_addr sender) { struct babel_proto *p = e->proto; struct babel_route *r; TRACE(D_PACKETS, "Forwarding seqno request for %I/%d router-id %lR seqno %d", e->n.prefix, e->n.pxlen, in->router_id, in->seqno); WALK_LIST(r, e->routes) { if ((r->router_id == in->router_id) && !OUR_ROUTE(r) && !ipa_equal(r->neigh->addr, sender)) { if (!babel_cache_seqno_request(p, e->n.prefix, e->n.pxlen, in->router_id, in->seqno)) return; union babel_msg msg = {}; msg.type = BABEL_TLV_SEQNO_REQUEST; msg.seqno_request.plen = in->plen; msg.seqno_request.seqno = in->seqno; msg.seqno_request.hop_count = in->hop_count-1; msg.seqno_request.router_id = in->router_id; msg.seqno_request.prefix = e->n.prefix; babel_send_unicast(&msg, r->neigh->ifa, r->neigh->addr); return; } } } /* * TLV handlers */ void babel_handle_ack_req(union babel_msg *m, struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; struct babel_msg_ack_req *msg = &m->ack_req; TRACE(D_PACKETS, "Handling ACK request nonce %d interval %d", msg->nonce, msg->interval); babel_send_ack(ifa, msg->sender, msg->nonce); } void babel_handle_hello(union babel_msg *m, struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; struct babel_msg_hello *msg = &m->hello; TRACE(D_PACKETS, "Handling hello seqno %d interval %d", msg->seqno, msg->interval); struct babel_neighbor *n = babel_get_neighbor(ifa, msg->sender); babel_update_hello_history(n, msg->seqno, msg->interval); if (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS) babel_send_ihu(ifa, n); } void babel_handle_ihu(union babel_msg *m, struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; struct babel_msg_ihu *msg = &m->ihu; /* Ignore IHUs that are not about us */ if ((msg->ae != BABEL_AE_WILDCARD) && !ipa_equal(msg->addr, ifa->addr)) return; TRACE(D_PACKETS, "Handling IHU rxcost %d interval %d", msg->rxcost, msg->interval); struct babel_neighbor *n = babel_get_neighbor(ifa, msg->sender); n->txcost = msg->rxcost; n->ihu_expiry = now + BABEL_IHU_EXPIRY_FACTOR(msg->interval); } /** * babel_handle_update - handle incoming route updates * @m: Incoming update TLV * @ifa: Interface the update was received on * * This function is called as a handler for update TLVs and handles the updating * and maintenance of route entries in Babel's internal routing cache. The * handling follows the actions described in the Babel RFC, and at the end of * each update handling, babel_select_route() is called on the affected entry to * optionally update the selected routes and propagate them to the core. */ void babel_handle_update(union babel_msg *m, struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; struct babel_msg_update *msg = &m->update; struct babel_neighbor *nbr; struct babel_entry *e; struct babel_source *s; struct babel_route *r; node *n; int feasible; TRACE(D_PACKETS, "Handling update for %I/%d with seqno %d metric %d", msg->prefix, msg->plen, msg->seqno, msg->metric); nbr = babel_find_neighbor(ifa, msg->sender); if (!nbr) { DBG("Babel: Haven't heard from neighbor %I; ignoring update.\n", msg->sender); return; } if (msg->router_id == p->router_id) { DBG("Babel: Ignoring update for our own router ID.\n"); return; } /* * RFC section 3.5.4: * * When a Babel node receives an update (id, prefix, seqno, metric) from a * neighbour neigh with a link cost value equal to cost, it checks whether it * already has a routing table entry indexed by (neigh, id, prefix). * * If no such entry exists: * * o if the update is unfeasible, it is ignored; * * o if the metric is infinite (the update is a retraction), the update is * ignored; * * o otherwise, a new route table entry is created, indexed by (neigh, id, * prefix), with seqno equal to seqno and an advertised metric equal to the * metric carried by the update. * * If such an entry exists: * * o if the entry is currently installed and the update is unfeasible, then * the behaviour depends on whether the router-ids of the two entries match. * If the router-ids are different, the update is treated as though it were * a retraction (i.e., as though the metric were FFFF hexadecimal). If the * router-ids are equal, the update is ignored; * * o otherwise (i.e., if either the update is feasible or the entry is not * currently installed), then the entry's sequence number, advertised * metric, metric, and router-id are updated and, unless the advertised * metric is infinite, the route's expiry timer is reset to a small multiple * of the Interval value included in the update. */ /* Retraction */ if (msg->metric == BABEL_INFINITY) { if (msg->wildcard) { /* * Special case: This is a retraction of all prefixes announced by this * neighbour (see second-to-last paragraph of section 4.4.9 in the RFC). */ WALK_LIST(n, nbr->routes) { r = SKIP_BACK(struct babel_route, neigh_route, n); r->metric = BABEL_INFINITY; babel_select_route(r->e); } } else { e = babel_find_entry(p, msg->prefix, msg->plen); if (!e) return; /* The route entry indexed by neighbour */ r = babel_find_route(e, nbr); if (!r) return; r->metric = BABEL_INFINITY; babel_select_route(e); } /* Done with retractions */ return; } e = babel_get_entry(p, msg->prefix, msg->plen); r = babel_find_route(e, nbr); /* the route entry indexed by neighbour */ s = babel_find_source(e, msg->router_id); /* for feasibility */ feasible = babel_is_feasible(s, msg->seqno, msg->metric); if (!r) { if (!feasible) return; r = babel_get_route(e, nbr); r->advert_metric = msg->metric; r->router_id = msg->router_id; r->metric = babel_compute_metric(nbr, msg->metric); r->next_hop = msg->next_hop; r->seqno = msg->seqno; } else if (r == r->e->selected_in && !feasible) { /* * Route is installed and update is infeasible - we may lose the route, * so send a unicast seqno request (section 3.8.2.2 second paragraph). */ babel_unicast_seqno_request(r); if (msg->router_id == r->router_id) return; /* Treat as retraction */ r->metric = BABEL_INFINITY; } else { /* Last paragraph above - update the entry */ r->advert_metric = msg->metric; r->metric = babel_compute_metric(nbr, msg->metric); r->next_hop = msg->next_hop; r->router_id = msg->router_id; r->seqno = msg->seqno; r->expiry_interval = BABEL_ROUTE_EXPIRY_FACTOR(msg->interval); r->expires = now + r->expiry_interval; if (r->expiry_interval > BABEL_ROUTE_REFRESH_INTERVAL) r->refresh_time = now + r->expiry_interval - BABEL_ROUTE_REFRESH_INTERVAL; /* If the route is not feasible at this point, it means it is from another neighbour than the one currently selected; so send a unicast seqno request to try to get a better route (section 3.8.2.2 last paragraph). */ if (!feasible) babel_unicast_seqno_request(r); } babel_select_route(e); } void babel_handle_route_request(union babel_msg *m, struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; struct babel_msg_route_request *msg = &m->route_request; /* RFC 6126 3.8.1.1 */ /* Wildcard request - full update on the interface */ if (msg->full) { TRACE(D_PACKETS, "Handling wildcard route request"); ifa->want_triggered = 1; return; } TRACE(D_PACKETS, "Handling route request for %I/%d", msg->prefix, msg->plen); /* Non-wildcard request - see if we have an entry for the route. If not, send a retraction, otherwise send an update. */ struct babel_entry *e = babel_find_entry(p, msg->prefix, msg->plen); if (!e) { babel_send_retraction(ifa, msg->prefix, msg->plen); } else { babel_trigger_iface_update(ifa); e->updated = now; } } void babel_handle_seqno_request(union babel_msg *m, struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; struct babel_msg_seqno_request *msg = &m->seqno_request; /* RFC 6126 3.8.1.2 */ TRACE(D_PACKETS, "Handling seqno request for %I/%d router-id %lR seqno %d hop count %d", msg->prefix, msg->plen, msg->router_id, msg->seqno, msg->hop_count); /* Ignore if we have no such entry or entry has infinite metric */ struct babel_entry *e = babel_find_entry(p, msg->prefix, msg->plen); if (!e || !e->selected_out || (e->selected_out->metric == BABEL_INFINITY)) return; /* Trigger update on incoming interface if we have a selected route with different router id or seqno no smaller than requested */ struct babel_route *r = e->selected_out; if ((r->router_id != msg->router_id) || ge_mod64k(r->seqno, msg->seqno)) { babel_trigger_iface_update(ifa); e->updated = now; return; } /* Seqno is larger; check if we own the router id */ if (msg->router_id == p->router_id) { /* Ours; update seqno and trigger global update */ p->update_seqno++; babel_trigger_update(p); } else { /* Not ours; forward if TTL allows it */ if (msg->hop_count > 1) babel_forward_seqno_request(e, msg, msg->sender); } } /* * Babel interfaces */ /** * babel_iface_timer - Babel interface timer handler * @t: Timer * * This function is called by the per-interface timer and triggers sending of * periodic Hello's and both triggered and periodic updates. Periodic Hello's * and updates are simply handled by setting the next_{hello,regular} variables * on the interface, and triggering an update (and resetting the variable) * whenever 'now' exceeds that value. * * For triggered updates, babel_trigger_iface_update() will set the * want_triggered field on the interface to a timestamp value. If this is set * (and the next_triggered time has passed; this is a rate limiting mechanism), * babel_send_update() will be called with this timestamp as the second * parameter. This causes updates to be send consisting of only the routes that * have changed since the time saved in want_triggered. * * Mostly when an update is triggered, the route being modified will be set to * the value of 'now' at the time of the trigger; the >= comparison for * selecting which routes to send in the update will make sure this is included. */ static void babel_iface_timer(timer *t) { struct babel_iface *ifa = t->data; struct babel_proto *p = ifa->proto; bird_clock_t hello_period = ifa->cf->hello_interval; bird_clock_t update_period = ifa->cf->update_interval; if (now >= ifa->next_hello) { babel_send_hello(ifa, (ifa->cf->type == BABEL_IFACE_TYPE_WIRELESS || ifa->hello_seqno % BABEL_IHU_INTERVAL_FACTOR == 0)); ifa->next_hello += hello_period * (1 + (now - ifa->next_hello) / hello_period); } if (now >= ifa->next_regular) { TRACE(D_EVENTS, "Sending regular updates on %s", ifa->ifname); babel_send_update(ifa, 0); ifa->next_regular += update_period * (1 + (now - ifa->next_regular) / update_period); ifa->want_triggered = 0; p->triggered = 0; } else if (ifa->want_triggered && (now >= ifa->next_triggered)) { TRACE(D_EVENTS, "Sending triggered updates on %s", ifa->ifname); babel_send_update(ifa, ifa->want_triggered); ifa->next_triggered = now + MIN(5, update_period / 2 + 1); ifa->want_triggered = 0; p->triggered = 0; } bird_clock_t next_event = MIN(ifa->next_hello, ifa->next_regular); tm_start(ifa->timer, ifa->want_triggered ? 1 : (next_event - now)); } static inline void babel_iface_kick_timer(struct babel_iface *ifa) { if (ifa->timer->expires > (now + 1)) tm_start(ifa->timer, 1); } static void babel_iface_start(struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; TRACE(D_EVENTS, "Starting interface %s", ifa->ifname); ifa->next_hello = now + (random() % ifa->cf->hello_interval) + 1; ifa->next_regular = now + (random() % ifa->cf->update_interval) + 1; ifa->next_triggered = now + MIN(5, ifa->cf->update_interval / 2 + 1); ifa->want_triggered = 0; /* We send an immediate update (below) */ tm_start(ifa->timer, 1); ifa->up = 1; babel_send_hello(ifa, 0); babel_send_wildcard_retraction(ifa); babel_send_wildcard_request(ifa); babel_send_update(ifa, 0); /* Full update */ } static void babel_iface_stop(struct babel_iface *ifa) { struct babel_proto *p = ifa->proto; struct babel_neighbor *nbr; struct babel_route *r; node *n; TRACE(D_EVENTS, "Stopping interface %s", ifa->ifname); /* * Rather than just flushing the neighbours, we set the metric of their routes * to infinity. This allows us to keep the neighbour hello state for when the * interface comes back up. The routes will also be kept until they expire. */ WALK_LIST(nbr, ifa->neigh_list) { WALK_LIST(n, nbr->routes) { r = SKIP_BACK(struct babel_route, neigh_route, n); r->metric = BABEL_INFINITY; r->expires = now + r->expiry_interval; babel_select_route(r->e); } } tm_stop(ifa->timer); ifa->up = 0; } static inline int babel_iface_link_up(struct babel_iface *ifa) { return !ifa->cf->check_link || (ifa->iface->flags & IF_LINK_UP); } static void babel_iface_update_state(struct babel_iface *ifa) { int up = ifa->sk && babel_iface_link_up(ifa); if (up == ifa->up) return; if (up) babel_iface_start(ifa); else babel_iface_stop(ifa); } static void babel_iface_update_buffers(struct babel_iface *ifa) { if (!ifa->sk) return; uint mtu = MAX(BABEL_MIN_MTU, ifa->iface->mtu); uint rbsize = ifa->cf->rx_buffer ?: mtu; uint tbsize = ifa->cf->tx_length ?: mtu; rbsize = MAX(rbsize, tbsize); sk_set_rbsize(ifa->sk, rbsize); sk_set_tbsize(ifa->sk, tbsize); ifa->tx_length = tbsize - BABEL_OVERHEAD; } static struct babel_iface* babel_find_iface(struct babel_proto *p, struct iface *what) { struct babel_iface *ifa; WALK_LIST (ifa, p->interfaces) if (ifa->iface == what) return ifa; return NULL; } static void babel_iface_locked(struct object_lock *lock) { struct babel_iface *ifa = lock->data; struct babel_proto *p = ifa->proto; if (!babel_open_socket(ifa)) { log(L_ERR "%s: Cannot open socket for %s", p->p.name, ifa->iface->name); return; } babel_iface_update_buffers(ifa); babel_iface_update_state(ifa); } static void babel_add_iface(struct babel_proto *p, struct iface *new, struct babel_iface_config *ic) { struct babel_iface *ifa; TRACE(D_EVENTS, "Adding interface %s", new->name); pool *pool = rp_new(p->p.pool, new->name); ifa = mb_allocz(pool, sizeof(struct babel_iface)); ifa->proto = p; ifa->iface = new; ifa->cf = ic; ifa->pool = pool; ifa->ifname = new->name; add_tail(&p->interfaces, NODE ifa); struct ifa *addr; WALK_LIST(addr, new->addrs) if (ipa_is_link_local(addr->ip)) ifa->addr = addr->ip; if (ipa_zero(ifa->addr)) log(L_WARN "%s: Cannot find link-local addr on %s", p->p.name, new->name); init_list(&ifa->neigh_list); ifa->hello_seqno = 1; ifa->timer = tm_new_set(ifa->pool, babel_iface_timer, ifa, 0, 0); init_list(&ifa->msg_queue); ifa->send_event = ev_new(ifa->pool); ifa->send_event->hook = babel_send_queue; ifa->send_event->data = ifa; struct object_lock *lock = olock_new(ifa->pool); lock->type = OBJLOCK_UDP; lock->addr = IP6_BABEL_ROUTERS; lock->port = ifa->cf->port; lock->iface = ifa->iface; lock->hook = babel_iface_locked; lock->data = ifa; olock_acquire(lock); } static void babel_remove_iface(struct babel_proto *p, struct babel_iface *ifa) { TRACE(D_EVENTS, "Removing interface %s", ifa->iface->name); struct babel_neighbor *n; WALK_LIST_FIRST(n, ifa->neigh_list) babel_flush_neighbor(n); rem_node(NODE ifa); rfree(ifa->pool); /* contains ifa itself, locks, socket, etc */ } static void babel_if_notify(struct proto *P, unsigned flags, struct iface *iface) { struct babel_proto *p = (void *) P; struct babel_config *cf = (void *) P->cf; if (iface->flags & IF_IGNORE) return; if (flags & IF_CHANGE_UP) { struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, iface->addr); /* we only speak multicast */ if (!(iface->flags & IF_MULTICAST)) return; if (ic) babel_add_iface(p, iface, ic); return; } struct babel_iface *ifa = babel_find_iface(p, iface); if (!ifa) return; if (flags & IF_CHANGE_DOWN) { babel_remove_iface(p, ifa); return; } if (flags & IF_CHANGE_MTU) babel_iface_update_buffers(ifa); if (flags & IF_CHANGE_LINK) babel_iface_update_state(ifa); } static int babel_reconfigure_iface(struct babel_proto *p, struct babel_iface *ifa, struct babel_iface_config *new) { struct babel_iface_config *old = ifa->cf; /* Change of these options would require to reset the iface socket */ if ((new->port != old->port) || (new->tx_tos != old->tx_tos) || (new->tx_priority != old->tx_priority)) return 0; TRACE(D_EVENTS, "Reconfiguring interface %s", ifa->iface->name); ifa->cf = new; if (ifa->next_regular > (now + new->update_interval)) ifa->next_regular = now + (random() % new->update_interval) + 1; if ((new->tx_length != old->tx_length) || (new->rx_buffer != old->rx_buffer)) babel_iface_update_buffers(ifa); if (new->check_link != old->check_link) babel_iface_update_state(ifa); if (ifa->up) babel_iface_kick_timer(ifa); return 1; } static void babel_reconfigure_ifaces(struct babel_proto *p, struct babel_config *cf) { struct iface *iface; WALK_LIST(iface, iface_list) { if (! (iface->flags & IF_UP)) continue; struct babel_iface *ifa = babel_find_iface(p, iface); struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, NULL); if (ifa && ic) { if (babel_reconfigure_iface(p, ifa, ic)) continue; /* Hard restart */ log(L_INFO "%s: Restarting interface %s", p->p.name, ifa->iface->name); babel_remove_iface(p, ifa); babel_add_iface(p, iface, ic); } if (ifa && !ic) babel_remove_iface(p, ifa); if (!ifa && ic) babel_add_iface(p, iface, ic); } } /* * Debugging and info output functions */ static void babel_dump_source(struct babel_source *s) { debug("Source router_id %lR seqno %d metric %d expires %d\n", s->router_id, s->seqno, s->metric, s->expires ? s->expires-now : 0); } static void babel_dump_route(struct babel_route *r) { debug("Route neigh %I if %s seqno %d metric %d/%d router_id %lR expires %d\n", r->neigh ? r->neigh->addr : IPA_NONE, r->neigh ? r->neigh->ifa->ifname : "(none)", r->seqno, r->advert_metric, r->metric, r->router_id, r->expires ? r->expires-now : 0); } static void babel_dump_entry(struct babel_entry *e) { struct babel_source *s; struct babel_route *r; debug("Babel: Entry %I/%d:\n", e->n.prefix, e->n.pxlen); WALK_LIST(s,e->sources) { debug(" "); babel_dump_source(s); } WALK_LIST(r,e->routes) { debug(" "); if (r == e->selected_out) debug("*"); if (r == e->selected_in) debug("+"); babel_dump_route(r); } } static void babel_dump_neighbor(struct babel_neighbor *n) { debug("Neighbor %I txcost %d hello_map %x next seqno %d expires %d/%d\n", n->addr, n->txcost, n->hello_map, n->next_hello_seqno, n->hello_expiry ? n->hello_expiry - now : 0, n->ihu_expiry ? n->ihu_expiry - now : 0); } static void babel_dump_iface(struct babel_iface *ifa) { struct babel_neighbor *n; debug("Babel: Interface %s addr %I rxcost %d type %d hello seqno %d intervals %d %d\n", ifa->ifname, ifa->addr, ifa->cf->rxcost, ifa->cf->type, ifa->hello_seqno, ifa->cf->hello_interval, ifa->cf->update_interval); WALK_LIST(n, ifa->neigh_list) { debug(" "); babel_dump_neighbor(n); } } static void babel_dump(struct proto *P) { struct babel_proto *p = (struct babel_proto *) P; struct babel_iface *ifa; debug("Babel: router id %lR update seqno %d\n", p->router_id, p->update_seqno); WALK_LIST(ifa, p->interfaces) babel_dump_iface(ifa); FIB_WALK(&p->rtable, n) { babel_dump_entry((struct babel_entry *) n); } FIB_WALK_END; } static void babel_get_route_info(rte *rte, byte *buf, ea_list *attrs) { buf += bsprintf(buf, " (%d/%d) [%lR]", rte->pref, rte->u.babel.metric, rte->u.babel.router_id); } static int babel_get_attr(eattr *a, byte *buf, int buflen UNUSED) { switch (a->id) { case EA_BABEL_METRIC: bsprintf(buf, "metric: %d", a->u.data); return GA_FULL; case EA_BABEL_ROUTER_ID: { u64 rid = 0; memcpy(&rid, a->u.ptr->data, sizeof(u64)); bsprintf(buf, "router_id: %lR", rid); return GA_FULL; } default: return GA_UNKNOWN; } } void babel_show_interfaces(struct proto *P, char *iff) { struct babel_proto *p = (void *) P; struct babel_iface *ifa = NULL; struct babel_neighbor *nbr = NULL; if (p->p.proto_state != PS_UP) { cli_msg(-1023, "%s: is not up", p->p.name); cli_msg(0, ""); return; } cli_msg(-1023, "%s:", p->p.name); cli_msg(-1023, "%-10s %-6s %7s %6s %6s", "Interface", "State", "RX cost", "Nbrs", "Timer"); WALK_LIST(ifa, p->interfaces) { if (iff && !patmatch(iff, ifa->iface->name)) continue; int nbrs = 0; WALK_LIST(nbr, ifa->neigh_list) nbrs++; int timer = MIN(ifa->next_regular, ifa->next_hello) - now; cli_msg(-1023, "%-10s %-6s %7u %6u %6u", ifa->iface->name, (ifa->up ? "Up" : "Down"), ifa->cf->rxcost, nbrs, MAX(timer, 0)); } cli_msg(0, ""); } void babel_show_neighbors(struct proto *P, char *iff) { struct babel_proto *p = (void *) P; struct babel_iface *ifa = NULL; struct babel_neighbor *n = NULL; struct babel_route *r = NULL; if (p->p.proto_state != PS_UP) { cli_msg(-1024, "%s: is not up", p->p.name); cli_msg(0, ""); return; } cli_msg(-1024, "%s:", p->p.name); cli_msg(-1024, "%-25s %-10s %6s %6s %10s", "IP address", "Interface", "Metric", "Routes", "Next hello"); WALK_LIST(ifa, p->interfaces) { if (iff && !patmatch(iff, ifa->iface->name)) continue; WALK_LIST(n, ifa->neigh_list) { int rts = 0; WALK_LIST(r, n->routes) rts++; int timer = n->hello_expiry - now; cli_msg(-1024, "%-25I %-10s %6u %6u %10u", n->addr, ifa->iface->name, n->txcost, rts, MAX(timer, 0)); } } cli_msg(0, ""); } void babel_show_entries(struct proto *P) { struct babel_proto *p = (void *) P; struct babel_entry *e = NULL; struct babel_source *s = NULL; struct babel_route *r = NULL; char ipbuf[STD_ADDRESS_P_LENGTH+5]; char ridbuf[ROUTER_ID_64_LENGTH+1]; if (p->p.proto_state != PS_UP) { cli_msg(-1025, "%s: is not up", p->p.name); cli_msg(0, ""); return; } cli_msg(-1025, "%s:", p->p.name); cli_msg(-1025, "%-29s %-23s %6s %5s %7s %7s", "Prefix", "Router ID", "Metric", "Seqno", "Expires", "Sources"); FIB_WALK(&p->rtable, n) { e = (struct babel_entry *) n; r = e->selected_in ? e->selected_in : e->selected_out; int srcs = 0; WALK_LIST(s, e->sources) srcs++; bsprintf(ipbuf, "%I/%u", e->n.prefix, e->n.pxlen); if (r) { if (r->router_id == p->router_id) bsprintf(ridbuf, "%s", ""); else bsprintf(ridbuf, "%lR", r->router_id); int time = r->expires ? r->expires - now : 0; cli_msg(-1025, "%-29s %-23s %6u %5u %7u %7u", ipbuf, ridbuf, r->metric, r->seqno, MAX(time, 0), srcs); } else { cli_msg(-1025, "%-29s %-44s %7u", ipbuf, "", srcs); } } FIB_WALK_END; cli_msg(0, ""); } /* * Babel protocol glue */ /** * babel_timer - global timer hook * @t: Timer * * This function is called by the global protocol instance timer and handles * expiration of routes and neighbours as well as pruning of the seqno request * cache. */ static void babel_timer(timer *t) { struct babel_proto *p = t->data; babel_expire_routes(p); babel_expire_seqno_requests(p); babel_expire_neighbors(p); } static inline void babel_kick_timer(struct babel_proto *p) { if (p->timer->expires > (now + 1)) tm_start(p->timer, 1); } static struct ea_list * babel_prepare_attrs(struct linpool *pool, ea_list *next, uint metric, u64 router_id) { struct ea_list *l = lp_alloc(pool, sizeof(struct ea_list) + 2*sizeof(eattr)); struct adata *rid = lp_alloc(pool, sizeof(struct adata) + sizeof(u64)); rid->length = sizeof(u64); memcpy(&rid->data, &router_id, sizeof(u64)); l->next = next; l->flags = EALF_SORTED; l->count = 2; l->attrs[0].id = EA_BABEL_METRIC; l->attrs[0].flags = 0; l->attrs[0].type = EAF_TYPE_INT | EAF_TEMP; l->attrs[0].u.data = metric; l->attrs[1].id = EA_BABEL_ROUTER_ID; l->attrs[1].flags = 0; l->attrs[1].type = EAF_TYPE_OPAQUE | EAF_TEMP; l->attrs[1].u.ptr = rid; return l; } static int babel_import_control(struct proto *P, struct rte **rt, struct ea_list **attrs, struct linpool *pool) { struct babel_proto *p = (void *) P; /* Prepare attributes with initial values */ if ((*rt)->attrs->source != RTS_BABEL) *attrs = babel_prepare_attrs(pool, NULL, 0, p->router_id); return 0; } static struct ea_list * babel_make_tmp_attrs(struct rte *rt, struct linpool *pool) { return babel_prepare_attrs(pool, NULL, rt->u.babel.metric, rt->u.babel.router_id); } static void babel_store_tmp_attrs(struct rte *rt, struct ea_list *attrs) { rt->u.babel.metric = ea_get_int(attrs, EA_BABEL_METRIC, 0); } /* * babel_rt_notify - core tells us about new route (possibly our own), * so store it into our data structures. */ static void babel_rt_notify(struct proto *P, struct rtable *table UNUSED, struct network *net, struct rte *new, struct rte *old, struct ea_list *attrs) { struct babel_proto *p = (void *) P; struct babel_entry *e; struct babel_route *r; if (new) { /* Update */ e = babel_get_entry(p, net->n.prefix, net->n.pxlen); if (new->attrs->src->proto != P) { r = babel_get_route(e, NULL); r->seqno = p->update_seqno; r->router_id = p->router_id; r->metric = 0; /* FIXME: should be selectable */ } else r = e->selected_in; if (r != e->selected_out) { e->selected_out = r; e->updated = now; babel_trigger_update(p); } } else { /* Withdraw */ e = babel_find_entry(p, net->n.prefix, net->n.pxlen); if (!e || !e->selected_out) return; if (OUR_ROUTE(e->selected_out)) { /* * We originate this route, so set its metric to infinity and set an * expiry time. This causes a retraction to be sent, and later the route * to be flushed once the hold time has passed. */ e->selected_out->metric = BABEL_INFINITY; e->selected_out->expires = now + BABEL_HOLD_TIME; e->updated = now; babel_trigger_update(p); } else { /* * This is a route originating from someone else that was lost; presumably * because an export filter was updated to filter it. This means we can't * set the metric to infinity (it would be overridden on subsequent * updates from the peer originating the route), so just clear the * exported route. * * This causes peers to expire the route after a while (like if we just * shut down), but it's the best we can do in these circumstances; and * since export filters presumably aren't updated that often this is * acceptable. */ e->selected_out = NULL; } } } static int babel_rte_better(struct rte *new, struct rte *old) { return new->u.babel.metric < old->u.babel.metric; } static int babel_rte_same(struct rte *new, struct rte *old) { return ((new->u.babel.router_id == old->u.babel.router_id) && (new->u.babel.metric == old->u.babel.metric)); } static struct proto * babel_init(struct proto_config *cfg) { struct proto *P = proto_new(cfg, sizeof(struct babel_proto)); P->accept_ra_types = RA_OPTIMAL; P->if_notify = babel_if_notify; P->rt_notify = babel_rt_notify; P->import_control = babel_import_control; P->make_tmp_attrs = babel_make_tmp_attrs; P->store_tmp_attrs = babel_store_tmp_attrs; P->rte_better = babel_rte_better; P->rte_same = babel_rte_same; return P; } static int babel_start(struct proto *P) { struct babel_proto *p = (void *) P; struct babel_config *cf = (void *) P->cf; fib_init(&p->rtable, P->pool, sizeof(struct babel_entry), 0, babel_init_entry); init_list(&p->interfaces); p->timer = tm_new_set(P->pool, babel_timer, p, 0, 1); tm_start(p->timer, 2); p->update_seqno = 1; p->router_id = proto_get_router_id(&cf->c); p->route_slab = sl_new(P->pool, sizeof(struct babel_route)); p->source_slab = sl_new(P->pool, sizeof(struct babel_source)); p->msg_slab = sl_new(P->pool, sizeof(struct babel_msg_node)); p->seqno_slab = sl_new(P->pool, sizeof(struct babel_seqno_request)); init_list(&p->seqno_cache); p->log_pkt_tbf = (struct tbf){ .rate = 1, .burst = 5 }; return PS_UP; } static inline void babel_iface_shutdown(struct babel_iface *ifa) { if (ifa->sk) { babel_send_wildcard_retraction(ifa); babel_send_queue(ifa); } } static int babel_shutdown(struct proto *P) { struct babel_proto *p = (void *) P; struct babel_iface *ifa; TRACE(D_EVENTS, "Shutdown requested"); WALK_LIST(ifa, p->interfaces) babel_iface_shutdown(ifa); return PS_DOWN; } static int babel_reconfigure(struct proto *P, struct proto_config *c) { struct babel_proto *p = (void *) P; struct babel_config *new = (void *) c; TRACE(D_EVENTS, "Reconfiguring"); p->p.cf = c; babel_reconfigure_ifaces(p, new); babel_trigger_update(p); babel_kick_timer(p); return 1; } struct protocol proto_babel = { .name = "Babel", .template = "babel%d", .attr_class = EAP_BABEL, .preference = DEF_PREF_BABEL, .config_size = sizeof(struct babel_config), .init = babel_init, .dump = babel_dump, .start = babel_start, .shutdown = babel_shutdown, .reconfigure = babel_reconfigure, .get_route_info = babel_get_route_info, .get_attr = babel_get_attr };