December 2022 - Bird-users

[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

logging via udp
by Alexander Zubkov 13 Dec '23

13 Dec '23

Hello, Made some dirty patch for myself to allow bird to send logs via udp. But it may be useful not only for me, so posting it here. It could be useful when server experiencing high IO-load. As syslog and file operations in bird are blocking, it can be blocked on writing to it for indefinite time, which could lead to various problems like protocol timeouts. So udp logging comes in handy here. The tradeoff is that we can miss some logs if they are not processed in time. You can specify udp log destination like that: log udp [host IP|"hostname"] [port NUMBER|"portname"] ... By default it uses destination ip 127.0.0.1 and port 514. There are some constraints like not much error handling. And this destination replaces file destination, i.e. you can not use those simultaneously and it may leak descriptors and some memory probably if both are specified. It also makes a new socket every time configuration is reloaded even if there is no change in options, but this is not a great deal.

2 9

BIRD show bgp summary for cli
by Roman Bulakh 14 Jun '23

14 Jun '23

Hi, we use BIRD in our environment, and it would be very nice to have some command like `show bgp summary` in juniper. This command show information about peer IP, peer AS, last update, prefixes received/best/exported and last state. Example: bird> show bgp summary Peer AS Last state change Prfx rcvd/best/export State X.X.X.X asXXXX 2021-01-27 6786/6785/109000 Established Y.Y.Y.Y asYYYY 2020-12-16 0/0/0 Passive BGP Error: Hold timer expired The are patch created for BIRD 1.3.4 and 1.3.6, but it would be good to have this in upstream software, without rebuilding and patching. as I understand it, no functionality should be affected by these changes, this is only a visual update for cli. Old patches describes at pages: https://marc.info/?l=bird-users&m=132155489919052&w=2 http://trubka.network.cz/pipermail/bird-users/attachments/20120228/a1499be7… https://bird-users.network.narkive.com/Px6EH3yl/bird-1-3-6-show-bgp-summary…

4 3

Adding more then one bgp community at once
by Борис Коваленко 05 May '23

05 May '23

Hello! Is this possible to add many communites at once? bgp_community.add([(1,1), (1,2)]) is wrong "Setting clist attribute to non-clist value" Regards, Boris -- С уважением, Борис Коваленко

4 5

Expiration for ROA tables until when the VRP is valid?
by Robert Scheck 07 Mar '23

07 Mar '23

Hello all, rpki-client recently implemented the "expires" instruction for roa-sets that OpenBGPD provides [1][2]. As of writing, BIRD does not seem to have something similar...any chance for it? From my understanding this only applies to included ROA files with VRP, not to RTR. [1] https://man.openbsd.org/bgpd.conf#roa-set [2] https://github.com/rpki-client/rpki-client-openbsd/commit/7bf63da6ec80f37bd… Kind regards Robert Scheck

3 7

[PATCH] Babel: add RFC9229 (v4 via v6) support
by andreas＠rammhold.de 06 Mar '23

06 Mar '23

From: Andreas Rammhold <andreas(a)rammhold.de> This implements [RFC9229] an IPv4 via IPv6 extension to the Babel routing protocol that allows annoncing routes to an IPv4 prefix with an IPv6 next-hop, which makes it possible for IPv4 traffic to flow through interfaces that have not been assigned an IPv4 address. The implementation is compatible with the current Babeld version (the relevant changes can be seen in the [babeld PR]). I've verified this with a few VMs in the following setup: Bird <- v4 only -> Bird <- v6 only -> Babeld <- v4 only -> Babeld Each routing daemon was running on their own VM and had L2 connectivity to only its direct neighbors. At the nodes at the edges v4 networks have been announced and full end-to-end communication was possible over the mixed AF network. The v6 only link between Babel and Bird (at the "center" of the above setup) did transport the v4 packets via the v6 link-local next hop addresses just as expected. Thanks to Toke Høiland-Jørgensen for early review on this work. [RFC9229]: https://www.ietf.org/rfc/rfc9229.txt [babeld PR]: https://github.com/jech/babeld/pull/56 Acked-by: Toke Høiland-Jørgensen <toke(a)toke.dk> --- This is a rebase of the patches from the previous two RFC rounds on this ML: * https://trubka.network.cz/pipermail/bird-users/2022-April/016046.html <20201215020627.30942-1-andreas(a)rammhold.de> * http://trubka.network.cz/pipermail/bird-users/2020-December/015082.html <20201215020627.30942-1-andreas(a)rammhold.de> I'd like to drive this to the finish goal soon. I've been using it ever since and know of other users as well. Is there anything that should still be changed? doc/bird.sgml | 6 +++ proto/babel/babel.c | 28 ++++++++--- proto/babel/babel.h | 3 ++ proto/babel/config.Y | 5 +- proto/babel/packets.c | 106 +++++++++++++++++++++++++++++------------- 5 files changed, 109 insertions(+), 39 deletions(-) diff --git a/doc/bird.sgml b/doc/bird.sgml index 50657ebf..a7cedaee 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -1934,6 +1934,7 @@ protocol babel [<name>] { algorithm ( hmac sha1 | hmac sha256 | hmac sha384 | hmac sha512 | blake2s128 | blake2s256 | blake2b256 | blake2b512 ); }; + ipv4 via ipv6 <switch>; }; } </code> @@ -2042,6 +2043,11 @@ protocol babel [<name>] { protocol will only accept HMAC-based algorithms or one of the Blake algorithms, and the length of the supplied password string must match the key size used by the selected algorithm. + + <tag><label id="babel-ipv4-via-ipv6">ipv4 via ipv6 <m/switch/</tag> + If enabled, Bird will accept and emit IPv4-via-IPv6 routes when IPv4 + addresses are absent from the interface as described in RFC9229. + Default: yes. </descrip> <sect1>Attributes diff --git a/proto/babel/babel.c b/proto/babel/babel.c index ecfd2763..52a27256 100644 --- a/proto/babel/babel.c +++ b/proto/babel/babel.c @@ -981,8 +981,17 @@ babel_send_update_(struct babel_iface *ifa, btime changed, struct fib *rtable) msg.update.router_id = e->router_id; net_copy(&msg.update.net, e->n.addr); - msg.update.next_hop = ((e->n.addr->type == NET_IP4) ? - ifa->next_hop_ip4 : ifa->next_hop_ip6); + if (e->n.addr->type == NET_IP4) { + /* Always prefer v4 nexthop if set */ + if(!ipa_zero(ifa->next_hop_ip4)) + msg.update.next_hop = ifa->next_hop_ip4; + + /* Only send v4-via-v6 if enabled */ + else if (ifa->cf->ip4_via_ip6) + msg.update.next_hop = ifa->next_hop_ip6; + } else { + msg.update.next_hop = ifa->next_hop_ip6; + } /* Do not send route if next hop is unknown, e.g. no configured IPv4 address */ if (ipa_zero(msg.update.next_hop)) @@ -1277,6 +1286,12 @@ babel_handle_update(union babel_msg *m, struct babel_iface *ifa) return; } + /* Reject IPv4 via IPv6 routes if disabled */ + if (!ifa->cf->ip4_via_ip6 && msg->net.type == NET_IP4 && ipa_is_ip6(msg->next_hop)) { + DBG("Babel: Ignoring disabled IPv4 via IPv6 route.\n"); + return; + } + /* Regular update */ e = babel_get_entry(p, &msg->net); r = babel_get_route(p, e, nbr); /* the route entry indexed by neighbour */ @@ -1682,7 +1697,7 @@ babel_iface_update_addr4(struct babel_iface *ifa) ip_addr addr4 = ifa->iface->addr4 ? ifa->iface->addr4->ip : IPA_NONE; ifa->next_hop_ip4 = ipa_nonzero(ifa->cf->next_hop_ip4) ? ifa->cf->next_hop_ip4 : addr4; - if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel) + if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel && !ifa->cf->ip4_via_ip6) log(L_WARN "%s: Missing IPv4 next hop address for %s", p->p.name, ifa->ifname); if (ifa->up) @@ -2074,8 +2089,8 @@ babel_show_interfaces(struct proto *P, const char *iff) } cli_msg(-1023, "%s:", p->p.name); - cli_msg(-1023, "%-10s %-6s %-5s %7s %6s %7s %-15s %s", - "Interface", "State", "Auth", "RX cost", "Nbrs", "Timer", + cli_msg(-1023, "%-10s %-6s %-5s %-12s %7s %6s %7s %-15s %s", + "Interface", "State", "Auth", "IPv4 via Ip6", "RX cost", "Nbrs", "Timer", "Next hop (v4)", "Next hop (v6)"); WALK_LIST(ifa, p->interfaces) @@ -2088,10 +2103,11 @@ babel_show_interfaces(struct proto *P, const char *iff) nbrs++; btime timer = MIN(ifa->next_regular, ifa->next_hello) - current_time(); - cli_msg(-1023, "%-10s %-6s %-5s %7u %6u %7t %-15I %I", + cli_msg(-1023, "%-10s %-6s %-5s %-12s %7u %6u %7t %-15I %I", ifa->iface->name, (ifa->up ? "Up" : "Down"), (ifa->cf->auth_type == BABEL_AUTH_MAC ? (ifa->cf->auth_permissive ? "Perm" : "Yes") : "No"), + (ifa->cf->ip4_via_ip6 ? "Yes" : "No"), ifa->cf->rxcost, nbrs, MAX(timer, 0), ifa->next_hop_ip4, ifa->next_hop_ip6); } diff --git a/proto/babel/babel.h b/proto/babel/babel.h index 8b6da3c8..034a17db 100644 --- a/proto/babel/babel.h +++ b/proto/babel/babel.h @@ -112,6 +112,7 @@ enum babel_ae_type { BABEL_AE_IP4 = 1, BABEL_AE_IP6 = 2, BABEL_AE_IP6_LL = 3, + BABEL_AE_IPV4_VIA_IPV6 = 4, BABEL_AE_MAX }; @@ -151,6 +152,8 @@ struct babel_iface_config { uint mac_num_keys; /* Number of configured HMAC keys */ uint mac_total_len; /* Total digest length for all configured keys */ list *passwords; /* Passwords for authentication */ + + u8 ip4_via_ip6; /* Enable IPv4 via IPv6 */ }; struct babel_proto { diff --git a/proto/babel/config.Y b/proto/babel/config.Y index 05210fa4..7190f099 100644 --- a/proto/babel/config.Y +++ b/proto/babel/config.Y @@ -25,7 +25,8 @@ CF_DECLS 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) + ENTRIES, RANDOMIZE, ROUTER, ID, AUTHENTICATION, NONE, MAC, PERMISSIVE, + VIA) CF_GRAMMAR @@ -67,6 +68,7 @@ babel_iface_start: BABEL_IFACE->tx_tos = IP_PREC_INTERNET_CONTROL; BABEL_IFACE->tx_priority = sk_priority_control; BABEL_IFACE->check_link = 1; + BABEL_IFACE->ip4_via_ip6 = 1; }; @@ -143,6 +145,7 @@ babel_iface_item: | CHECK LINK bool { BABEL_IFACE->check_link = $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"); } + | IPV4 VIA IPV6 bool { BABEL_IFACE->ip4_via_ip6 = $4; } | AUTHENTICATION NONE { BABEL_IFACE->auth_type = BABEL_AUTH_NONE; } | AUTHENTICATION MAC { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; BABEL_IFACE->auth_permissive = 0; } | AUTHENTICATION MAC PERMISSIVE { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; BABEL_IFACE->auth_permissive = 1; } diff --git a/proto/babel/packets.c b/proto/babel/packets.c index d4acc170..9a71673a 100644 --- a/proto/babel/packets.c +++ b/proto/babel/packets.c @@ -167,9 +167,11 @@ struct babel_parse_state { u64 router_id; /* Router ID used in subsequent updates */ u8 def_ip6_prefix[16]; /* Implicit IPv6 prefix in network order */ u8 def_ip4_prefix[4]; /* Implicit IPv4 prefix in network order */ + u8 def_ip4viaip6_prefix[4]; /* Implicit IPv4 prefix in network order */ u8 router_id_seen; /* router_id field is valid */ u8 def_ip6_prefix_seen; /* def_ip6_prefix is valid */ u8 def_ip4_prefix_seen; /* def_ip4_prefix is valid */ + u8 def_ip4viaip6_prefix_seen; /* def_ip4viaip6_prefix is valid*/ u8 current_tlv_endpos; /* End of self-terminating TLVs (offset from start) */ u8 sadr_enabled; u8 is_unicast; @@ -515,9 +517,6 @@ babel_read_ihu(struct babel_tlv *hdr, union babel_msg *m, msg->addr = IPA_NONE; msg->sender = state->saddr; - if (msg->ae >= BABEL_AE_MAX) - return PARSE_IGNORE; - /* * We only actually read link-local IPs. In every other case, the addr field * will be 0 but validation will succeed. The handler takes care of these @@ -530,13 +529,13 @@ babel_read_ihu(struct babel_tlv *hdr, union babel_msg *m, if (TLV_OPT_LENGTH(tlv) < 4) return PARSE_ERROR; state->current_tlv_endpos += 4; - break; + return PARSE_SUCCESS; case BABEL_AE_IP6: if (TLV_OPT_LENGTH(tlv) < 16) return PARSE_ERROR; state->current_tlv_endpos += 16; - break; + return PARSE_SUCCESS; case BABEL_AE_IP6_LL: if (TLV_OPT_LENGTH(tlv) < 8) @@ -544,10 +543,10 @@ babel_read_ihu(struct babel_tlv *hdr, union babel_msg *m, msg->addr = ipa_from_ip6(get_ip6_ll(&tlv->addr)); state->current_tlv_endpos += 8; - break; + return PARSE_SUCCESS; } - return PARSE_SUCCESS; + return PARSE_IGNORE; } static uint @@ -647,6 +646,47 @@ babel_read_next_hop(struct babel_tlv *hdr, union babel_msg *m UNUSED, return PARSE_IGNORE; } + +/* This is called directly from babel_read_next_hop to handle the ip4 address + compression state */ +static int +babel_get_ip4_prefix(struct babel_tlv_update *tlv, + struct babel_msg_update *msg, + u8 *def_prefix_seen, + u8 (*def_prefix)[], + ip_addr next_hop, + int len) +{ + if (tlv->plen > IP4_MAX_PREFIX_LENGTH) + return PARSE_ERROR; + + /* Cannot omit data if there is no saved prefix */ + if (tlv->omitted && !*def_prefix_seen) + return PARSE_ERROR; + + /* Update must have next hop, unless it is retraction */ + if (ipa_zero(next_hop) && msg->metric != BABEL_INFINITY) + return PARSE_IGNORE; + + /* Merge saved prefix and received prefix parts */ + u8 buf[4] = {}; + memcpy(buf, *def_prefix, tlv->omitted); + memcpy(buf + tlv->omitted, tlv->addr, len); + + ip4_addr prefix4 = get_ip4(buf); + net_fill_ip4(&msg->net, prefix4, tlv->plen); + + if (tlv->flags & BABEL_UF_DEF_PREFIX) + { + put_ip4(*def_prefix, prefix4); + *def_prefix_seen = 1; + } + + msg->next_hop = next_hop; + + return PARSE_SUCCESS; +} + /* This is called directly from babel_write_update() and returns -1 if a next hop should be written but there is not enough space. */ static int @@ -696,6 +736,7 @@ static int babel_read_update(struct babel_tlv *hdr, union babel_msg *m, struct babel_parse_state *state) { + int rc; struct babel_tlv_update *tlv = (void *) hdr; struct babel_msg_update *msg = &m->update; @@ -706,7 +747,6 @@ babel_read_update(struct babel_tlv *hdr, union babel_msg *m, /* Length of received prefix data without omitted part */ int len = BYTES(tlv->plen) - (int) tlv->omitted; - u8 buf[16] = {}; if ((len < 0) || ((uint) len > TLV_OPT_LENGTH(tlv))) return PARSE_ERROR; @@ -724,31 +764,20 @@ babel_read_update(struct babel_tlv *hdr, union babel_msg *m, break; case BABEL_AE_IP4: - if (tlv->plen > IP4_MAX_PREFIX_LENGTH) - return PARSE_ERROR; + rc = babel_get_ip4_prefix(tlv, msg, &state->def_ip4_prefix_seen, + &state->def_ip4_prefix, state->next_hop_ip4, + len); + if (rc != PARSE_SUCCESS) + return rc; - /* Cannot omit data if there is no saved prefix */ - if (tlv->omitted && !state->def_ip4_prefix_seen) - return PARSE_ERROR; - - /* Update must have next hop, unless it is retraction */ - if (ipa_zero(state->next_hop_ip4) && (msg->metric != BABEL_INFINITY)) - return PARSE_IGNORE; - - /* Merge saved prefix and received prefix parts */ - memcpy(buf, state->def_ip4_prefix, tlv->omitted); - memcpy(buf + tlv->omitted, tlv->addr, len); - - ip4_addr prefix4 = get_ip4(buf); - net_fill_ip4(&msg->net, prefix4, tlv->plen); - - if (tlv->flags & BABEL_UF_DEF_PREFIX) - { - put_ip4(state->def_ip4_prefix, prefix4); - state->def_ip4_prefix_seen = 1; - } + break; - msg->next_hop = state->next_hop_ip4; + case BABEL_AE_IPV4_VIA_IPV6: + rc = babel_get_ip4_prefix(tlv, msg, &state->def_ip4viaip6_prefix_seen, + &state->def_ip4viaip6_prefix, state->next_hop_ip6, + len); + if (rc != PARSE_SUCCESS) + return rc; break; @@ -761,6 +790,7 @@ babel_read_update(struct babel_tlv *hdr, union babel_msg *m, return PARSE_ERROR; /* Merge saved prefix and received prefix parts */ + u8 buf[16] = {}; memcpy(buf, state->def_ip6_prefix, tlv->omitted); memcpy(buf + tlv->omitted, tlv->addr, len); @@ -863,7 +893,11 @@ babel_write_update(struct babel_tlv *hdr, union babel_msg *m, } else if (msg->net.type == NET_IP4) { - tlv->ae = BABEL_AE_IP4; + if (!ipa_zero(msg->next_hop) && ipa_is_ip6(msg->next_hop)) + tlv->ae = BABEL_AE_IPV4_VIA_IPV6; + else + tlv->ae = BABEL_AE_IP4; + tlv->plen = net4_pxlen(&msg->net); put_ip4_px(tlv->addr, &msg->net); } @@ -931,7 +965,11 @@ babel_read_route_request(struct babel_tlv *hdr, union babel_msg *m, msg->full = 1; return PARSE_SUCCESS; + /* RFC9229 section 2.3: When receiving requests, AEs 1 (IPv4) and 4 + * (v4-via-v6) MUST be treated in the same manner. + */ case BABEL_AE_IP4: + case BABEL_AE_IPV4_VIA_IPV6: if (tlv->plen > IP4_MAX_PREFIX_LENGTH) return PARSE_ERROR; @@ -1032,7 +1070,11 @@ babel_read_seqno_request(struct babel_tlv *hdr, union babel_msg *m, case BABEL_AE_WILDCARD: return PARSE_ERROR; + /* RFC9229 section 2.3: When receiving requests, AEs 1 (IPv4) and 4 + * (v4-via-v6) MUST be treated in the same manner. + */ case BABEL_AE_IP4: + case BABEL_AE_IPV4_VIA_IPV6: if (tlv->plen > IP4_MAX_PREFIX_LENGTH) return PARSE_ERROR; -- 2.38.1

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BIRD 2.0.{7,10} MED not actually send for learned routes if export table on is set
by Inrin 04 Feb '23

04 Feb '23

Greetings, I noticed during setting up a peering that the MED is not actually send to my peer, although bird shows it in the export. We confirmed this via tcpdump on both ends. After debugging a bit, I noticed that this only affects “learned” routes but routes from the static protocol worked just fine. After disabling the “export table” feature, the MED was send out just fine. Is this behaviour expected? This behaviour is reproducible in BIRD 2.0.7 and 2.0.10 with the following scenario (Configs to test are attached): R0 is connected to R1 and R2 R0, R1 and R2 send each one route R0 sets the MED to 300 R1 sets the MED to 100 R2 sets the MED to 200 Setting “export table on;” yields the following results: # Bird shows the MED in the export R0 $ ./birdc s r all export R1 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [static1 02:05:56.604] * (200) Type: static univ BGP.med: 300 198.18.2.0/24 unicast [R2 02:11:51.132 from 198.19.0.2] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420002 BGP.next_hop: 198.19.0.2 BGP.med: 300 BGP.local_pref: 100 R0 $ ./birdc s r all export R2 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [static1 02:05:56.604] * (200) Type: static univ BGP.med: 300 198.18.1.0/24 unicast [R1 02:11:51.133 from 198.19.0.1] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420001 BGP.next_hop: 198.19.0.1 BGP.med: 300 BGP.local_pref: 100 R0 # But on R1, R2 it does not appear for learned routes: R1 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.2.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420002 BGP.next_hop: 198.19.0.0 BGP.local_pref: 100 R1 $ R2 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 02:11:51.132 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.1.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420001 BGP.next_hop: 198.19.0.0 BGP.local_pref: 100 R2 $ Setting “export table off;” yield the expected result: R1 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 03:15:47.147 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.2.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420002 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 R1 $ R2 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.1.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420001 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 R2 $

6 11

[PATCH] feature to keep protocol's state while configuring
by Alexander Zubkov 29 Jan '23

29 Jan '23

Hello. I have created a patch (attached) with new protocol option: disabled keep on|off. To keep the protocol's state while loading new config. It is useful when protocols disabled manually in the runtime, but we want to keep that state when loading new config. Patch is attached. I have made it against the current int-new branch.

3 16

[PATCH] Don't treat 0/8 and 240/4 specially in IPv4 classification
by Seth David Schoen 01 Jan '23

01 Jan '23

With the exception of 0.0.0.0 and 255.255.255.255, which have additional special meanings, treat 0/8 and 240/4 as normal unicast addresses by default. This is because some people are experimenting with using these addresses as regular unicast (either for private addresses or for potential future public addresses). On the public Internet, they would still currently be regarded as bogons and one could make (maybe by default) a bogon-filtering rule in bird.conf that would not permit these addresses to be routed, e.g. with a pair of static routes route 0.0.0.0/8 prohibit; route 240.0.0.0/4 prohibit; or simply route 0.0.0.0/8 blackhole; route 240.0.0.0/4 blackhole; Dave Taht, who wrote a prior version of this patch, suggested that in any case it is better to have bogons defined in a configuration file than hard-coded in software. --- lib/ip.c | 7 +++++-- lib/ip.h | 2 +- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/lib/ip.c b/lib/ip.c index 4c5fa47f..e13bbce0 100644 --- a/lib/ip.c +++ b/lib/ip.c @@ -87,8 +87,10 @@ ip4_classify(ip4_addr ad) if (b < 0xe0) { - if (b == 0x00) /* 0.0.0.0/8 This network */ + if (a == 0x00000000) /* 0.0.0.0/32 Unset address */ return IADDR_INVALID; + /* 0.0.0.0/8 is otherwise reserved, but + * some people are using it or trying to */ if (b == 0x7f) /* 127.0.0.0/8 Loopback address */ return IADDR_HOST | SCOPE_HOST; @@ -107,7 +109,8 @@ ip4_classify(ip4_addr ad) if (a == 0xffffffff) /* 255.255.255.255 Broadcast address */ return IADDR_BROADCAST | SCOPE_LINK; - return IADDR_HOST | SCOPE_SITE; /* 240.0.0.0/4 Reserved / private */ + return IADDR_HOST | SCOPE_UNIVERSE; /* 240.0.0.0/4 Reserved / private, but + * some people are using it or trying to */ } int diff --git a/lib/ip.h b/lib/ip.h index 9eef2e16..875b9f5e 100644 --- a/lib/ip.h +++ b/lib/ip.h @@ -245,7 +245,7 @@ static inline int ip6_is_v4mapped(ip6_addr a) #define ipa_is_link_local(x) ip6_is_link_local(x) static inline int ip4_is_unicast(ip4_addr a) -{ return _I(a) < 0xe0000000; } +{ return _I(a) < 0xe0000000 || (_I(a) >= 0xf0000000 && _I(a) != 0xffffffff); } /* XXXX remove */ static inline int ipa_classify_net(ip_addr a) -- 2.25.1

8 12

[PATCH v5] babel: Rework seqno request handling
by Toke Høiland-Jørgensen 24 Dec '22

24 Dec '22

The seqno request retransmission handling was tracking the destination that a forwarded request was being sent to and always retransmitting to that same destination. This is unnecessary because we only need to retransmit requests we originate ourselves, not those we forward on behalf of others; in fact retransmitting on behalf of others can lead to exponential multiplication of requests, which would be bad. So rework the seqno request tracking so that instead of storing the destination of a request, we just track whether it was a request that we forwarded on behalf of another node, or if it was a request we originated ourselves. Forwarded requests are not retransmitted, they are only used for duplicate suppression, and for triggering an update when satisfied. If we end up originating a request that we previously forwarded, we "upgrade" the old request and restart the retransmit counter. One complication with this is that requests sent in response to unfeasible updates (section 3.8.2.2 of the RFC) have to be sent as unicast to a particular peer. However, we don't really need to retransmit those as there's no starvation when sending such a request; so we just change such requests to be one-off unicast requests that are not subject to retransmission or duplicate suppression. This is the same behaviour as babeld has for such requests. Signed-off-by: Toke Høiland-Jørgensen <toke(a)toke.dk> --- v5: - Set an explicit duplicate suppression time for forwarded requests instead of repurposing the multi-expiry logic for forwarded requests v4: - Keep the last parameter of babel_add_seqno_request() as the request target and resolve it in the caller - Drop check for 0-valued hop count - Add a comment explaining why we expire forwarded requests but don't retransmit them v3: - Rework the dupliate suppression logic to avoid suppressing resends v2: - Get rid of the neighbour pointer in the request state tracking - Change the resend behaviour to only resend requests we originated ourselves. proto/babel/babel.c | 152 ++++++++++++++++++++++++++++---------------- proto/babel/babel.h | 6 +- 2 files changed, 101 insertions(+), 57 deletions(-) diff --git a/proto/babel/babel.c b/proto/babel/babel.c index ecfd2763d737..e8476ff5f72f 100644 --- a/proto/babel/babel.c +++ b/proto/babel/babel.c @@ -53,7 +53,7 @@ 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 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); +static void babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr, struct babel_neighbor *tgt); static void babel_update_cost(struct babel_neighbor *n); static inline void babel_kick_timer(struct babel_proto *p); static inline void babel_iface_kick_timer(struct babel_iface *ifa); @@ -288,9 +288,6 @@ babel_expire_routes(struct babel_proto *p) babel_expire_routes_(p, &p->ip6_rtable); } -static inline int seqno_request_valid(struct babel_seqno_request *sr) -{ return !sr->nbr || sr->nbr->ifa; } - /* * Add seqno request to the table of pending requests (RFC 6216 3.2.6) and send * it to network. Do nothing if it is already in the table. @@ -299,50 +296,82 @@ static inline int seqno_request_valid(struct babel_seqno_request *sr) static void babel_add_seqno_request(struct babel_proto *p, struct babel_entry *e, u64 router_id, u16 seqno, u8 hop_count, - struct babel_neighbor *nbr) + struct babel_neighbor *tgt) { struct babel_seqno_request *sr; + btime now_ = current_time(); WALK_LIST(sr, e->requests) if (sr->router_id == router_id) { - /* Found matching or newer */ - if (ge_mod64k(sr->seqno, seqno) && seqno_request_valid(sr)) + /* + * To suppress duplicates, check if we already have a newer (higher seqno) + * outstanding request. If we do, suppress this request if the outstanding + * request is one we originated ourselves. If the outstanding request is + * forwarded, suppress only if this request is also one we're forwarding + * *and* we're within the duplicate suppression time of that request (see + * below). + */ + if (ge_mod64k(sr->seqno, seqno) && + (!sr->forwarded || (tgt && now_ < sr->dup_suppress_time))) return; - /* Found older */ rem_node(NODE sr); - if (sr->nbr) - rem_node(&sr->nbr_node); + /* Allow upgrading from forwarded to non-forwarded */ + if (!tgt) + sr->forwarded = 0; goto found; } /* No entries found */ sr = sl_allocz(p->seqno_slab); + sr->forwarded = !!tgt; found: sr->router_id = router_id; sr->seqno = seqno; - sr->hop_count = hop_count; + sr->hop_count = hop_count ?: BABEL_INITIAL_HOP_COUNT; sr->count = 0; - sr->expires = current_time() + BABEL_SEQNO_REQUEST_EXPIRY; - if (sr->nbr = nbr) - add_tail(&nbr->requests, &sr->nbr_node); + if (sr->forwarded) + { + /* + * We want to keep the entry around for a reasonable period of time so it + * can be used to trigger an update (through babel_satisfy_seqno_request()). + * However, duplicate suppression should only trigger for a short period of + * time so it suppresses duplicates from multiple sources, but not + * retransmissions from the same source. Hence we keep two timers. + */ + sr->expires = now_ + BABEL_SEQNO_FORWARD_EXPIRY; + sr->dup_suppress_time = now_ + BABEL_SEQNO_DUP_SUPPRESS_TIME; + } + else + { + sr->expires = now_ + BABEL_SEQNO_REQUEST_EXPIRY; + } add_tail(&e->requests, NODE sr); + babel_send_seqno_request(p, e, sr, tgt); +} - babel_send_seqno_request(p, e, sr); +static void +babel_generate_seqno_request(struct babel_proto *p, struct babel_entry *e, + u64 router_id, u16 seqno, struct babel_neighbor *tgt) +{ + struct babel_seqno_request req = { + .router_id = router_id, + .seqno = seqno, + .hop_count = BABEL_INITIAL_HOP_COUNT, + }; + + babel_send_seqno_request(p, e, &req, tgt); } static void babel_remove_seqno_request(struct babel_proto *p UNUSED, struct babel_seqno_request *sr) { - if (sr->nbr) - rem_node(&sr->nbr_node); - rem_node(NODE sr); sl_free(sr); } @@ -372,21 +401,14 @@ babel_expire_requests(struct babel_proto *p, struct babel_entry *e) WALK_LIST_DELSAFE(sr, srx, e->requests) { - /* Remove seqno requests sent to dead neighbors */ - if (!seqno_request_valid(sr)) - { - babel_remove_seqno_request(p, sr); - continue; - } - /* Handle expired requests - resend or remove */ if (sr->expires && sr->expires <= now_) { - if (sr->count < BABEL_SEQNO_REQUEST_RETRY) + if (!sr->forwarded && sr->count < BABEL_SEQNO_REQUEST_RETRY) { sr->count++; sr->expires += (BABEL_SEQNO_REQUEST_EXPIRY << sr->count); - babel_send_seqno_request(p, e, sr); + babel_send_seqno_request(p, e, sr, NULL); } else { @@ -431,7 +453,6 @@ babel_get_neighbor(struct babel_iface *ifa, ip_addr addr) nbr->cost = BABEL_INFINITY; nbr->init_expiry = current_time() + BABEL_INITIAL_NEIGHBOR_TIMEOUT; init_list(&nbr->routes); - init_list(&nbr->requests); add_tail(&ifa->neigh_list, NODE nbr); return nbr; @@ -452,10 +473,6 @@ babel_flush_neighbor(struct babel_proto *p, struct babel_neighbor *nbr) babel_flush_route(p, r); } - struct babel_seqno_request *sr; - WALK_LIST_FIRST2(sr, nbr_node, nbr->requests) - babel_remove_seqno_request(p, sr); - nbr->ifa = NULL; rem_node(NODE nbr); mb_free(nbr); @@ -903,22 +920,23 @@ babel_send_wildcard_request(struct babel_iface *ifa) } static void -babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr) +babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, + struct babel_seqno_request *sr, struct babel_neighbor *tgt) { union babel_msg msg = {}; msg.type = BABEL_TLV_SEQNO_REQUEST; - msg.seqno_request.hop_count = sr->hop_count ?: BABEL_INITIAL_HOP_COUNT; + msg.seqno_request.hop_count = sr->hop_count; msg.seqno_request.seqno = sr->seqno; msg.seqno_request.router_id = sr->router_id; net_copy(&msg.seqno_request.net, e->n.addr); - if (sr->nbr) + if (tgt) { TRACE(D_PACKETS, "Sending seqno request for %N router-id %lR seqno %d to %I on %s", - e->n.addr, sr->router_id, sr->seqno, sr->nbr->addr, sr->nbr->ifa->ifname); + e->n.addr, sr->router_id, sr->seqno, tgt->addr, tgt->ifa->ifname); - babel_send_unicast(&msg, sr->nbr->ifa, sr->nbr->addr); + babel_send_unicast(&msg, tgt->ifa, tgt->addr); } else { @@ -1285,10 +1303,13 @@ babel_handle_update(union babel_msg *m, struct babel_iface *ifa) metric = babel_compute_metric(nbr, msg->metric); best = e->selected; - /* RFC section 3.8.2.2 - Dealing with unfeasible updates */ + /* + * RFC section 3.8.2.2 - Dealing with unfeasible updates. Generate a one-off + * (not retransmitted) unicast seqno request to the originator of this update + */ if (!feasible && (metric != BABEL_INFINITY) && (!best || (r == best) || (metric < best->metric))) - babel_add_seqno_request(p, e, s->router_id, s->seqno + 1, 0, nbr); + babel_generate_seqno_request(p, e, s->router_id, s->seqno + 1, nbr); /* Special case - ignore unfeasible update to best route */ if (r == best && !feasible && (msg->router_id == r->router_id)) @@ -1353,6 +1374,32 @@ babel_handle_route_request(union babel_msg *m, struct babel_iface *ifa) } } +static struct babel_neighbor * +babel_find_seqno_request_tgt(struct babel_entry *e, struct babel_neighbor *skip) +{ + struct babel_route *r, *best_feasible = NULL, *best_any = NULL; + + WALK_LIST(r, e->routes) + { + if (r->neigh == skip) + continue; + + if (r->feasible && (!best_feasible || r->metric < best_feasible->metric)) + best_feasible = r; + + if (!best_any || r->metric < best_any->metric) + best_any = r; + } + + if (best_feasible) + return best_feasible->neigh; + + if (best_any) + return best_any->neigh; + + return NULL; +} + void babel_handle_seqno_request(union babel_msg *m, struct babel_iface *ifa) { @@ -1389,26 +1436,21 @@ babel_handle_seqno_request(union babel_msg *m, struct babel_iface *ifa) { /* Not ours; forward if TTL allows it */ - /* Find best admissible route */ - struct babel_route *r, *best1 = NULL, *best2 = NULL; - WALK_LIST(r, e->routes) - if ((r->router_id == msg->router_id) && !ipa_equal(r->neigh->addr, msg->sender)) - { - /* Find best feasible route */ - if ((!best1 || r->metric < best1->metric) && r->feasible) - best1 = r; + struct babel_neighbor *nbr, *tgt; - /* Find best not necessary feasible route */ - if (!best2 || r->metric < best2->metric) - best2 = r; - } + nbr = babel_find_neighbor(ifa, msg->sender); + if (!nbr) + return; - /* If no route is found, do nothing */ - r = best1 ?: best2; - if (!r) + tgt = babel_find_seqno_request_tgt(e, nbr); + if (!tgt) + { + TRACE(D_PACKETS, "Couldn't find a neighbour to forward seqno request for %N router-id %lR seqno %d to", + e->n.addr, msg->router_id, msg->seqno); return; + } - babel_add_seqno_request(p, e, msg->router_id, msg->seqno, msg->hop_count-1, r->neigh); + babel_add_seqno_request(p, e, msg->router_id, msg->seqno, msg->hop_count-1, tgt); } } diff --git a/proto/babel/babel.h b/proto/babel/babel.h index 8b6da3c8ce91..b6e56ecb30a6 100644 --- a/proto/babel/babel.h +++ b/proto/babel/babel.h @@ -48,6 +48,8 @@ #define BABEL_ROUTE_REFRESH_FACTOR(X) ((btime)(X)*5/2) /* 2.5 */ #define BABEL_SEQNO_REQUEST_RETRY 4 #define BABEL_SEQNO_REQUEST_EXPIRY (2 S_) +#define BABEL_SEQNO_FORWARD_EXPIRY (10 S_) +#define BABEL_SEQNO_DUP_SUPPRESS_TIME (1 S_) #define BABEL_GARBAGE_INTERVAL (300 S_) #define BABEL_RXCOST_WIRED 96 #define BABEL_RXCOST_WIRELESS 256 @@ -240,7 +242,6 @@ struct babel_neighbor { btime init_expiry; list routes; /* Routes this neighbour has sent us (struct babel_route) */ - list requests; /* Seqno requests bound to this neighbor */ }; struct babel_source { @@ -276,7 +277,8 @@ struct babel_seqno_request { u8 hop_count; u8 count; btime expires; - struct babel_neighbor *nbr; + btime dup_suppress_time; + u8 forwarded; }; struct babel_entry { -- 2.39.0

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