October 2024 - Bird-users

[PATCH] Babel: allow enabling link quality estimation manually
by Nick Cao 09 Apr '25

09 Apr '25

Link quality estimation is useful for link types other than wireless, especially when using babel with tunnels where packet losses do occur. --- doc/bird.sgml | 6 ++++++ proto/babel/babel.c | 19 ++++++------------- proto/babel/babel.h | 1 + proto/babel/config.Y | 5 ++++- 4 files changed, 17 insertions(+), 14 deletions(-) diff --git a/doc/bird.sgml b/doc/bird.sgml index 8041faa9..417ec030 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -2032,6 +2032,12 @@ protocol babel [<name>] { hardware drivers or platforms do not implement this feature. Default: yes. + <tag><label id="babel-link-quality">link quality <m/switch/</tag> + If set, link quality estimation is performed on this interface. + Link quality is measured by packet loss and is used for computing + metrics of routes going through this interface. Default: yes for + wireless interfaces, otherwise no. + <tag><label id="babel-next-hop-ipv4">next hop ipv4 <m/address/</tag> Set the next hop address advertised for IPv4 routes advertised on this interface. Default: the preferred IPv4 address of the interface. diff --git a/proto/babel/babel.c b/proto/babel/babel.c index 7f0cca73..6a238d75 100644 --- a/proto/babel/babel.c +++ b/proto/babel/babel.c @@ -593,21 +593,15 @@ babel_update_cost(struct babel_neighbor *nbr) if (!rcv || !nbr->ifa->up) goto done; - switch (cf->type) - { - case BABEL_IFACE_TYPE_WIRED: - case BABEL_IFACE_TYPE_TUNNEL: + if (!cf->link_quality) { /* k-out-of-j selection - Appendix 2.1 in the RFC. */ /* Link is bad if less than cf->limit/16 of expected hellos were received */ - if (rcv * 16 < cf->limit * max) - break; - - rxcost = cf->rxcost; - txcost = nbr->txcost; - break; - - case BABEL_IFACE_TYPE_WIRELESS: + if (!(rcv * 16 < cf->limit * max)) { + rxcost = cf->rxcost; + txcost = nbr->txcost; + } + } else { /* * ETX - Appendix 2.2 in the RFC. * @@ -622,7 +616,6 @@ babel_update_cost(struct babel_neighbor *nbr) */ rxcost = MIN( cf->rxcost * max / rcv, BABEL_INFINITY); txcost = MIN(nbr->txcost * max / rcv, BABEL_INFINITY); - break; } if (cf->rtt_cost && nbr->srtt > cf->rtt_min) diff --git a/proto/babel/babel.h b/proto/babel/babel.h index edde4cab..d152d099 100644 --- a/proto/babel/babel.h +++ b/proto/babel/babel.h @@ -145,6 +145,7 @@ struct babel_iface_config { u8 type; u8 limit; /* Minimum number of Hellos to keep link up */ u8 check_link; + u8 link_quality; uint port; uint hello_interval; /* Hello interval, in us */ uint ihu_interval; /* IHU interval, in us */ diff --git a/proto/babel/config.Y b/proto/babel/config.Y index b8af0267..cbf873c5 100644 --- a/proto/babel/config.Y +++ b/proto/babel/config.Y @@ -26,7 +26,7 @@ CF_KEYWORDS(BABEL, INTERFACE, METRIC, RXCOST, HELLO, UPDATE, INTERVAL, PORT, TYPE, WIRED, WIRELESS, RX, TX, BUFFER, PRIORITY, LENGTH, CHECK, LINK, NEXT, HOP, IPV4, IPV6, BABEL_METRIC, SHOW, INTERFACES, NEIGHBORS, ENTRIES, RANDOMIZE, ROUTER, ID, AUTHENTICATION, NONE, MAC, PERMISSIVE, - EXTENDED, TUNNEL, RTT, MIN, MAX, DECAY, SEND, TIMESTAMPS) + EXTENDED, TUNNEL, RTT, MIN, MAX, DECAY, SEND, TIMESTAMPS, QUALITY) CF_GRAMMAR @@ -72,6 +72,7 @@ babel_iface_start: BABEL_IFACE->rtt_decay = BABEL_RTT_DECAY; BABEL_IFACE->rtt_send = 1; BABEL_IFACE->check_link = 1; + BABEL_IFACE->link_quality = 0; BABEL_IFACE->ext_next_hop = 1; }; @@ -84,6 +85,7 @@ babel_iface_finish: BABEL_IFACE->hello_interval = BABEL_HELLO_INTERVAL_WIRELESS; if (!BABEL_IFACE->rxcost) BABEL_IFACE->rxcost = BABEL_RXCOST_WIRELESS; + BABEL_IFACE->link_quality = 1; } else { @@ -156,6 +158,7 @@ babel_iface_item: | TX tos { BABEL_IFACE->tx_tos = $2; } | TX PRIORITY expr { BABEL_IFACE->tx_priority = $3; } | CHECK LINK bool { BABEL_IFACE->check_link = $3; } + | LINK QUALITY bool { BABEL_IFACE->link_quality = $3; } | NEXT HOP IPV4 ipa { BABEL_IFACE->next_hop_ip4 = $4; if (!ipa_is_ip4($4)) cf_error("Must be an IPv4 address"); } | NEXT HOP IPV6 ipa { BABEL_IFACE->next_hop_ip6 = $4; if (!ipa_is_ip6($4)) cf_error("Must be an IPv6 address"); } | EXTENDED NEXT HOP bool { BABEL_IFACE->ext_next_hop = $4; } -- 2.41.0

4 14

[PATCH] Bus error on ARMv7 when using OSPF
by Matthew Reeve 18 Dec '24

18 Dec '24

Hi, when using bird 2.0.8 on openwrt 21.02 (and other versions) on a Netgear R7800 router, if the OSPF protocol is used, either v2 or v3, bird immediately crashes on startup with: Fri Jun 11 14:41:11 2021 daemon.info bird: Started Fri Jun 11 14:41:11 2021 kern.err kernel: [ 3500.853248] Alignment trap: not handling instruction f44c0a1f at [<00035848>] Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.853283] 8<--- cut here --- Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.859363] Unhandled fault: alignment exception (0x801) at 0x007e0624 Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.862443] pgd = 0bbef4fd Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.868821] [007e0624] *pgd=5d6ca835, *pte=5c40b75f, *ppte=5c40bc7f This router uses an ARMv7 processor and the issue seems to be to do with memory alignment issues. I've debugged it and traced it to an access to the top_hash_entry struct. I've found that if I add the PACKED macro to the struct definition then it fixes the problem, as per this patch: --- a/proto/ospf/topology.h +++ b/proto/ospf/topology.h @@ -41,7 +41,7 @@ struct top_hash_entry u8 mode; /* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/ u8 nhs_reuse; /* Whether nhs nodes can be reused during merging. See a note in rt.c:add_cand() */ -}; +} PACKED; /* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */ Thanks.

4 11

Bird 3 Status
by Marcelo Balbinot 18 Dec '24

18 Dec '24

Hi BIRD Team, Could you give us a brief update on the status of version 3 ? Do you have any expected dates for a new release !? Thanks, -- Marcelo Balbinot

3 5

[PATCH v3] Babel: Replace internal route selection by bird's nest
by Daniel Gröber 11 Dec '24

11 Dec '24

This allows for filtering routes from specific interfaces and neighbours. With the current internal route selection proto babel exports only up to one route and an admin cannot do fine-grained filtering. To fix this we rip out the internal route selection entirely and put them all into the bird's nest instead. This appears to not actually be a breaking change as route announcement was already based on which routes bird would send back to babel_rt_notify filters shouldn't be able to tell the difference between a single and multiple routes AFAIK. --- Changes in v3: - Subsume FIB_RESTART v2 patch: instead of restarting FIB iteration we keep lists of actions to perform after FIB iteration is finished. proto/babel/babel.c | 269 +++++++++++++++++++------------------------- proto/babel/babel.h | 8 +- 2 files changed, 120 insertions(+), 157 deletions(-) diff --git a/proto/babel/babel.c b/proto/babel/babel.c index ff8b6b52..087fd95b 100644 --- a/proto/babel/babel.c +++ b/proto/babel/babel.c @@ -29,10 +29,11 @@ * 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. The function selects from feasible and reachable routes the - * one with the lowest metric to be announced to the core. + * The main route selection is done by the bird nest (heh). For each prefix we + * export all feasible routes to the core with a distinct source (rte_src) per + * neihbour. Bird will then notify us of the optimal one by calling + * babel_rt_notify and we remember which neighbour it selected in + * babel_entry.selected_nbr. */ #include <stdlib.h> @@ -50,7 +51,7 @@ static inline int ge_mod64k(uint a, uint b) { return (u16)(a - b) < 0x8000; } static void babel_expire_requests(struct babel_proto *p, struct babel_entry *e); -static void babel_select_route(struct babel_proto *p, struct babel_entry *e, struct babel_route *mod); +static void babel_announce_rte(struct babel_proto *p, struct babel_entry *e, struct babel_route *r); static inline void babel_announce_retraction(struct babel_proto *p, struct babel_entry *e); static void babel_send_route_request(struct babel_proto *p, struct babel_entry *e, struct babel_neighbor *n); static void babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr, struct babel_neighbor *n); @@ -164,13 +165,19 @@ babel_get_route(struct babel_proto *p, struct babel_entry *e, struct babel_neigh return r; } +static struct babel_route * +babel_get_selected_route(struct babel_proto *p, struct babel_entry *e) +{ + if (e->selected_nbr) + return babel_get_route(p, e, e->selected_nbr); + return NULL; +} + static inline void babel_retract_route(struct babel_proto *p, struct babel_route *r) { r->metric = r->advert_metric = BABEL_INFINITY; - - if (r == r->e->selected) - babel_select_route(p, r->e, r); + babel_announce_rte(p, r->e, r); } static void @@ -182,9 +189,6 @@ babel_flush_route(struct babel_proto *p UNUSED, struct babel_route *r) rem_node(NODE r); rem_node(&r->neigh_route); - if (r->e->selected == r) - r->e->selected = NULL; - sl_free(r); } @@ -200,6 +204,7 @@ babel_expire_route(struct babel_proto *p, struct babel_route *r) { r->metric = r->advert_metric = BABEL_INFINITY; r->expires = current_time() + cf->hold_time; + babel_announce_rte(p, r->e, r); } else { @@ -210,7 +215,7 @@ babel_expire_route(struct babel_proto *p, struct babel_route *r) static void babel_refresh_route(struct babel_proto *p, struct babel_route *r) { - if (r == r->e->selected) + if (r == babel_get_selected_route(p, r->e)) babel_send_route_request(p, r->e, r->neigh); r->refresh_time = 0; @@ -221,16 +226,15 @@ babel_expire_routes_(struct babel_proto *p, struct fib *rtable) { struct babel_config *cf = (void *) p->p.cf; struct babel_route *r, *rx; + struct babel_entry *retract_head = NULL, *delete_head = NULL; + struct babel_route *expire_head = NULL; struct fib_iterator fit; btime now_ = current_time(); - FIB_ITERATE_INIT(&fit, rtable); -loop: + FIB_ITERATE_INIT(&fit, rtable); FIB_ITERATE_START(rtable, &fit, struct babel_entry, e) { - int changed = 0; - WALK_LIST_DELSAFE(r, rx, e->routes) { if (r->refresh_time && r->refresh_time <= now_) @@ -238,23 +242,11 @@ loop: if (r->expires && r->expires <= now_) { - changed = changed || (r == e->selected); - babel_expire_route(p, r); + r->expire_next = expire_head; + expire_head = r; } } - 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() -> rtable change, invalidating hidden variables. - */ - FIB_ITERATE_PUT(&fit); - babel_select_route(p, e, NULL); - goto loop; - } - /* Clean up stale entries */ if ((e->valid == BABEL_ENTRY_STALE) && ((e->updated + cf->hold_time) <= now_)) e->valid = BABEL_ENTRY_DUMMY; @@ -262,9 +254,8 @@ loop: /* Clean up unreachable route */ if (e->unreachable && (!e->valid || (e->router_id == p->router_id))) { - FIB_ITERATE_PUT(&fit); - babel_announce_retraction(p, e); - goto loop; + e->retract_next = retract_head; + retract_head = e; } babel_expire_sources(p, e); @@ -273,12 +264,25 @@ loop: /* Remove empty entries */ if (!e->valid && EMPTY_LIST(e->routes) && EMPTY_LIST(e->sources) && EMPTY_LIST(e->requests)) { - FIB_ITERATE_PUT(&fit); - fib_delete(rtable, e); - goto loop; + e->delete_next = delete_head; + delete_head = e; } } FIB_ITERATE_END; + + for (struct babel_route *r_next, *r = expire_head; r ; r = r_next) { + r_next = r->expire_next; + babel_expire_route(p, r); + } + + for (struct babel_entry *e = retract_head; e ; e = e->retract_next) { + babel_announce_retraction(p, e); + } + + for (struct babel_entry *e_next, *e = delete_head; e ; e = e_next) { + e_next = e->delete_next; + fib_delete(rtable, e); + } } static void @@ -447,6 +451,7 @@ babel_get_neighbor(struct babel_iface *ifa, ip_addr addr) nbr = mb_allocz(ifa->pool, sizeof(struct babel_neighbor)); nbr->ifa = ifa; + nbr->src = rt_get_source(&p->p, idm_alloc(&p->src_ids)); nbr->addr = addr; nbr->rxcost = BABEL_INFINITY; nbr->txcost = BABEL_INFINITY; @@ -474,6 +479,8 @@ babel_flush_neighbor(struct babel_proto *p, struct babel_neighbor *nbr) } nbr->ifa = NULL; + + idm_free(&p->src_ids, nbr->src->private_id); rem_node(NODE nbr); mb_free(nbr); } @@ -634,11 +641,40 @@ done: WALK_LIST2(r, n, nbr->routes, neigh_route) { r->metric = babel_compute_metric(nbr, r->advert_metric); - babel_select_route(p, r->e, r); + babel_announce_rte(p, r->e, r); } } } +static void +babel_announce_rte_unreachable(struct babel_proto *p, struct babel_entry *e, u8 unreachable) +{ + struct channel *c = (e->n.addr->type == NET_IP4) ? p->ip4_channel : p->ip6_channel; + rte *rte = NULL; + + if (unreachable) { + /* Unreachable */ + rta a0 = { + .source = RTS_BABEL, + .scope = SCOPE_UNIVERSE, + .dest = RTD_UNREACHABLE, + .pref = 1, + }; + + rta *a = rta_lookup(&a0); + rte = rte_get_temp(a, p->p.main_source); + } + + e->unreachable = unreachable; + + /* Unlike the many neighbour routes we only want one unreachable route, for + * one it's ugly to have lots of unreachable routes (if we just did this right + * in babel_announce_rte) but we also loose access to the neibour rte_src id + * when the neighbour is deallocated. This happens on a different schedule + * than unreachable route removal. */ + rte_update2(c, e->n.addr, rte, p->p.main_source); +} + /** * babel_announce_rte - announce selected route to the core * @p: Babel protocol instance @@ -649,12 +685,11 @@ done: * the entry is valid and ours, the unreachable route is announced instead. */ static void -babel_announce_rte(struct babel_proto *p, struct babel_entry *e) +babel_announce_rte(struct babel_proto *p, struct babel_entry *e, struct babel_route *r) { - struct babel_route *r = e->selected; struct channel *c = (e->n.addr->type == NET_IP4) ? p->ip4_channel : p->ip6_channel; - if (r) + if (r->metric != BABEL_INFINITY && r->feasible) { rta a0 = { .source = RTS_BABEL, @@ -698,124 +733,27 @@ babel_announce_rte(struct babel_proto *p, struct babel_entry *e) a0.nh.flags = RNF_ONLINK; rta *a = rta_lookup(&a0); - rte *rte = rte_get_temp(a, p->p.main_source); + rte *rte = rte_get_temp(a, r->neigh->src); - e->unreachable = 0; - rte_update2(c, e->n.addr, rte, p->p.main_source); - } - else if (e->valid && (e->router_id != p->router_id)) - { - /* Unreachable */ - rta a0 = { - .source = RTS_BABEL, - .scope = SCOPE_UNIVERSE, - .dest = RTD_UNREACHABLE, - .pref = 1, - }; - - rta *a = rta_lookup(&a0); - rte *rte = rte_get_temp(a, p->p.main_source); - - e->unreachable = 1; - rte_update2(c, e->n.addr, rte, p->p.main_source); + rte_update2(c, e->n.addr, rte, r->neigh->src); + babel_announce_rte_unreachable(p, e, 0); } else - { - /* Retraction */ - e->unreachable = 0; - rte_update2(c, e->n.addr, NULL, p->p.main_source); - } + rte_update2(c, e->n.addr, NULL, r->neigh->src); } /* Special case of babel_announce_rte() just for retraction */ static inline void babel_announce_retraction(struct babel_proto *p, struct babel_entry *e) { + TRACE(D_EVENTS, "Retract unreachable route for %N", + e->n.addr); + struct channel *c = (e->n.addr->type == NET_IP4) ? p->ip4_channel : p->ip6_channel; e->unreachable = 0; rte_update2(c, e->n.addr, NULL, p->p.main_source); } - -/** - * babel_select_route - select best route for given route entry - * @p: Babel protocol instance - * @e: Babel entry to select the best route for - * @mod: Babel route that was modified or NULL if unspecified - * - * Select the best reachable and feasible route for a given prefix among the - * routes received from peers, and propagate it to the nest. This just selects - * the reachable and feasible route with the lowest metric, but keeps selected - * the old one in case of tie. - * - * 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. If the entry - * is valid and not owned by us, the unreachable route is announced to the nest - * (to blackhole packets going to it, as per section 2.8). It is later removed - * by babel_expire_routes(). Otherwise, the route is just removed from the nest. - * - * Argument @mod is used to optimize best route calculation. When specified, the - * function can assume that only the @mod route was modified to avoid full best - * route selection and announcement when non-best route was modified in minor - * way. The caller is advised to not call babel_select_route() when no change is - * done (e.g. periodic route updates) to avoid unnecessary announcements of the - * same best route. The caller is not required to call the function in case of a - * retraction of a non-best route. - * - * Note that the function does not active triggered updates. That is done by - * babel_rt_notify() when the change is propagated back to Babel. - */ -static void -babel_select_route(struct babel_proto *p, struct babel_entry *e, struct babel_route *mod) -{ - struct babel_route *r, *best = e->selected; - - /* Shortcut if only non-best was modified */ - if (mod && (mod != best)) - { - /* Either select modified route, or keep old best route */ - if ((mod->metric < (best ? best->metric : BABEL_INFINITY)) && mod->feasible) - best = mod; - else - return; - } - else - { - /* Selected route may be modified and no longer admissible */ - if (!best || (best->metric == BABEL_INFINITY) || !best->feasible) - best = NULL; - - /* Find the best feasible route from all routes */ - WALK_LIST(r, e->routes) - if ((r->metric < (best ? best->metric : BABEL_INFINITY)) && r->feasible) - best = r; - } - - if (best) - { - if (best != e->selected) - TRACE(D_EVENTS, "Picked new route for prefix %N: router-id %lR metric %d", - e->n.addr, best->router_id, best->metric); - } - else if (e->selected) - { - /* - * We have lost all feasible routes. We have to broadcast seqno request - * (Section 3.8.2.1) and keep unreachable route for a while (section 2.8). - * The later is done automatically by babel_announce_rte(). - */ - - TRACE(D_EVENTS, "Lost feasible route for prefix %N", e->n.addr); - if (e->valid && (e->selected->router_id == e->router_id)) - babel_add_seqno_request(p, e, e->selected->router_id, e->selected->seqno + 1, 0, NULL); - } - else - return; - - e->selected = best; - babel_announce_rte(p, e); -} - /* * Functions to send replies */ @@ -1300,7 +1238,7 @@ babel_handle_update(union babel_msg *m, struct babel_iface *ifa) s = babel_find_source(e, msg->router_id); /* for feasibility */ feasible = babel_is_feasible(s, msg->seqno, msg->metric); metric = babel_compute_metric(nbr, msg->metric); - best = e->selected; + best = babel_get_selected_route(p, e); /* * RFC section 3.8.2.2 - Dealing with unfeasible updates. Generate a one-off @@ -1338,7 +1276,7 @@ babel_handle_update(union babel_msg *m, struct babel_iface *ifa) e->updated = current_time(); } - babel_select_route(p, e, r); + babel_announce_rte(p, e, r); } void @@ -2003,10 +1941,10 @@ babel_dump_route(struct babel_route *r) } static void -babel_dump_entry(struct babel_entry *e) +babel_dump_entry(struct babel_proto *p, struct babel_entry *e) { struct babel_source *s; - struct babel_route *r; + struct babel_route *r, *best = babel_get_selected_route(p, e); debug("Babel: Entry %N:\n", e->n.addr); @@ -2016,7 +1954,7 @@ babel_dump_entry(struct babel_entry *e) WALK_LIST(r,e->routes) { debug(" "); - if (r == e->selected) debug("*"); + if (r == best) debug("*"); babel_dump_route(r); } } @@ -2057,12 +1995,12 @@ babel_dump(struct proto *P) FIB_WALK(&p->ip4_rtable, struct babel_entry, e) { - babel_dump_entry(e); + babel_dump_entry(p, e); } FIB_WALK_END; FIB_WALK(&p->ip6_rtable, struct babel_entry, e) { - babel_dump_entry(e); + babel_dump_entry(p, e); } FIB_WALK_END; } @@ -2186,7 +2124,7 @@ babel_show_entries_(struct babel_proto *p, struct fib *rtable) FIB_WALK(rtable, struct babel_entry, e) { - struct babel_route *r = NULL; + struct babel_route *r = NULL, *best = babel_get_selected_route(p, e); uint rts = 0, srcs = 0; node *n; @@ -2199,7 +2137,7 @@ babel_show_entries_(struct babel_proto *p, struct fib *rtable) if (e->valid) cli_msg(-1025, "%-*N %-23lR %6u %5u %7u %7u", width, e->n.addr, e->router_id, e->metric, e->seqno, rts, srcs); - else if (r = e->selected) + else if (r = best) cli_msg(-1025, "%-*N %-23lR %6u %5u %7u %7u", width, e->n.addr, r->router_id, r->metric, r->seqno, rts, srcs); else @@ -2236,10 +2174,10 @@ babel_show_routes_(struct babel_proto *p, struct fib *rtable) FIB_WALK(rtable, struct babel_entry, e) { - struct babel_route *r; + struct babel_route *r, *best = babel_get_selected_route(p, e); WALK_LIST(r, e->routes) { - char c = (r == e->selected) ? '*' : (r->feasible ? '+' : ' '); + char c = (r == best) ? '*' : (r->feasible ? '+' : ' '); btime time = r->expires ? r->expires - current_time() : 0; cli_msg(-1025, "%-*N %-25I %-10s %5u %c %5u %7t", width, e->n.addr, r->next_hop, r->neigh->ifa->ifname, @@ -2320,15 +2258,18 @@ babel_rt_notify(struct proto *P, struct channel *c UNUSED, struct network *net, { struct babel_proto *p = (void *) P; struct babel_entry *e; + struct babel_iface *ifa; + struct babel_neighbor *n; if (new) { /* Update */ + uint internal = new->src->proto == P; uint rt_seqno; uint rt_metric = ea_get_int(new->attrs->eattrs, EA_BABEL_METRIC, 0); u64 rt_router_id = 0; - if (new->src->proto == P) + if (internal) { rt_seqno = ea_find(new->attrs->eattrs, EA_BABEL_SEQNO)->u.data; eattr *e = ea_find(new->attrs->eattrs, EA_BABEL_ROUTER_ID); @@ -2350,6 +2291,18 @@ babel_rt_notify(struct proto *P, struct channel *c UNUSED, struct network *net, e = babel_get_entry(p, net->n.addr); + while (internal) { + ifa = babel_find_iface(p, new->attrs->nh.iface); + if (!ifa) break; + n = babel_find_neighbor(ifa, new->attrs->from); + if (!n) break; + e->selected_nbr = n; + break; + } + if (!internal) { + e->selected_nbr = NULL; + } + /* Activate triggered updates */ if ((e->valid != BABEL_ENTRY_VALID) || (e->router_id != rt_router_id)) @@ -2373,6 +2326,9 @@ babel_rt_notify(struct proto *P, struct channel *c UNUSED, struct network *net, e->valid = BABEL_ENTRY_STALE; e->metric = BABEL_INFINITY; + e->selected_nbr = NULL; + + babel_announce_rte_unreachable(p, e, 1); babel_trigger_update(p); e->updated = current_time(); @@ -2464,6 +2420,7 @@ babel_start(struct proto *P) 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)); + idm_init(&p->src_ids, P->pool, 8); p->log_pkt_tbf = (struct tbf){ .rate = 1, .burst = 5 }; diff --git a/proto/babel/babel.h b/proto/babel/babel.h index da8386b3..1d7e19f0 100644 --- a/proto/babel/babel.h +++ b/proto/babel/babel.h @@ -25,6 +25,7 @@ #include "lib/socket.h" #include "lib/string.h" #include "lib/timer.h" +#include "lib/idm.h" #define EA_BABEL_METRIC EA_CODE(PROTOCOL_BABEL, 0) #define EA_BABEL_ROUTER_ID EA_CODE(PROTOCOL_BABEL, 1) @@ -174,6 +175,7 @@ struct babel_proto { slab *source_slab; slab *msg_slab; slab *seqno_slab; + struct idm src_ids; struct tbf log_pkt_tbf; /* TBF for packet messages */ }; @@ -216,6 +218,7 @@ struct babel_iface { struct babel_neighbor { node n; struct babel_iface *ifa; + struct rte_src *src; ip_addr addr; u16 rxcost; /* Sent in last IHU */ @@ -256,6 +259,7 @@ struct babel_source { struct babel_route { node n; node neigh_route; + struct babel_route *expire_next; struct babel_entry *e; struct babel_neighbor *neigh; @@ -281,7 +285,9 @@ struct babel_seqno_request { }; struct babel_entry { - struct babel_route *selected; + struct babel_neighbor *selected_nbr; + + struct babel_entry *retract_next, *delete_next; list routes; /* Routes for this prefix (struct babel_route) */ list sources; /* Source entries for this prefix (struct babel_source). */ -- 2.30.2

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Route-type 5 support in BGP EVPN
by Ramanathan Selvamani 30 Oct '24

30 Oct '24

Hi Team, I would like to know about the below two things in BIRD support (1) Do you have any plan to support BGP EVPN Route-Type 5 (IP Prefix Route) as defined in RFC 9136 in the BIRD EVPN branch. (2) Do you have any plan to support two level recursive lookup to resolve nexthop for BGP routes. I mean the below comment in "rt_update_hostentry" function /* Recursive route should not depend on another recursive route */ Thanks, Ramanathan

2 2

BGP Flowspec VPNv4/VPNv6
by Vincent Bernat 26 Oct '24

26 Oct '24

Hey! I would be interested in implementing BGP Flowspec for VPNv4/VPNv6. Hacking flow4/flow6 to be VPNv4/VPNv6 instead of IPv4/IPv6 instead is easy, but I am unsure of the right way to *add* VPNv4/VPNv6. Should I add flowvpn4/flowvpn6 tables or reuse flow4/flow6 and only add "vpn4/vpn6 flow" channels to the BGP protocol? The difference with the MPLS case is that there is no FIB for Flowspec, so the design could be simplified. But, maybe we prefer to follow the existing design and have distinct tables for VPN and non-VPN cases? Thanks.

3 3

IPv6 Address Specific BGP Extended Community
by Eric Long 26 Oct '24

26 Oct '24

Hi all, BGP flowspec v6 [1] uses IPv6 address specific extended communities [2] for traffic actions, which seems to have no signs of support in BIRD (at least in BIRD 2). Is this planned to support in the future? Is there a good starting point/example where I can refer to to try to implement it in BIRD, since it seems to need to touch a lot of parts of the source code (parser, data types, protocols, etc.) Cheers, Eric

3 4

Functions with 2+ arguments
by Pim van Pelt 23 Oct '24

23 Oct '24

Hoi folks, Consider the following two functions in Bird v2.15.1: function test_ok(int var1) -> bool { if (bgp_large_community ~ [ (50869,1000,var1), (50869,2000,8298) ]) then return true; return false; } function test_nok(int var1; int var2) -> bool { if (bgp_large_community ~ [ (50869,1000,var1), (50869,2000,var2*)* ]) then return true; return false; } The first one parses fine, but the second function yields a parse error on bird: __filename__:199:66 Expression of type int expected Position 199:66 is the closing parenthesis directly after var2. I colored that paren red above. Is my construct or syntax incorrect in the test_nok() case? groet, Pim -- Pim van Pelt PBVP1-RIPE -https://ipng.ch/

2 1

Failing DNS resolution causes BGP sessions to flap
by Ondřej Caletka 21 Oct '24

21 Oct '24

Dear BIRD users, I have recently noticed an interesting issue. A newly set up BGP session between BIRD on our side and a remote party running whatever was taken down every hour or so. The reason for the session being terminated was Received: Hold timer expired. Looking at the logs, it turned out that this was caused by broken DNS resolver on the machine where BIRD is running. Whenever BIRD was trying to resolve the host name of the RPKI Validator cache, it got stuck for 24 seconds. This was apparently enough for the other BGP speaker to consider it dead and take the session down (the hold timers were shortened from the standard values there). Oct 15 13:45:51 vrtr-4.mtg.ripe.net bird[907]: rpki_validator: Cannot resolve hostname 'rpki-validator.mtg.ripe.net': > Oct 15 13:45:51 vrtr-4.mtg.ripe.net bird[907]: I/O loop cycle took 24009.001 ms for 1 events Oct 15 13:45:51 vrtr-4.mtg.ripe.net bird[907]: Kernel dropped some netlink messages, will resync on next scan. Oct 15 13:45:51 vrtr-4.mtg.ripe.net bird[907]: peer_as2852_v4: Received: Hold timer expired Oct 15 13:46:55 vrtr-4.mtg.ripe.net bird[907]: peer_as2852_v4.ipv4: Automatic RPKI reload not active for import This case was fixed by making sure DNS resolver works, but I still wonder whether this is a known limitation or whether this is something that can possibly be improved. -- Best regards, Ondřej Caletka

2 1

Re: Address update causing infinite loop
by Maria Matejka 21 Oct '24

21 Oct '24

Nice, gonna check whether it happens in my case. Thanks for your report, I'll let you know if i need anything more from you. Maria On 20 October 2024 23:25:46 GMT-04:00, benli ye <danielbenliye(a)gmail.com> wrote: >Hi! > >Yes, you are right. Only one thing that I need to correct is that address which is repeated added and deleted is not the next hop address, it’s just a normal address on the interface. >I will try to make it reproduce easily. > >Thanks, >Daniel > > >> On Oct 18, 2024, at 21:03, Maria Matějka <mq(a)jmq.cz> wrote: >> >> Hi! >> >> On Fri, Oct 18, 2024 at 08:50:18PM +0800, benli ye wrote: >> >> Thanks for your response. I have reproduced this issue in our test environment. However, it may not be easy to reproduce again. >> >> Our bird conf example: (image) I have make a shell script to add and remove an IP address of an interface repeatedly. Somehow, I get a 100% cpu issue for bird. >> >> So basically, before we dive into it. >> >> a device and kernel protocol >> a static protocol with lots of multipath routes >> repeatedly adding and deleting one of the nexthop addresses at the interface >> everything else seems irrelevant >> Do I understand that correctly? >> >> The reason why I’m asking – we need to catch the bug way earlier than when it hangs, as the hang is a symptom. The direct cause is somewhere else and it’s hard to find where without an actual reproducer. >> >> Thanks, >> Maria >> >> – >> Maria Matejka (she/her) | https://maria.jmq.cz/ >> > -- Maria Matejka (she/her) | BIRD Team Leader | CZ.NIC, z.s.p.o.

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