October 2018 - Bird-users

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

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Bug: BFD confuses sessions with identical IPv6 link-local addresses
by Julian Brost 14 Jan '21

14 Jan '21

Hi, I just tried to enable BFD for some OSPF and BGP connections and ran into an issue which BFD sessions flapping up and down and Bird logging many messages like these: bfd1: Bad packet from fe80::2 - unknown session id (130079069) bfd1: Bad packet from fe80::2 - unknown session id (3102513000) bfd1: Bad packet from fe80::2 - unknown session id (3650438750) bfd1: Bad packet from fe80::2 - unknown session id (1597034259) This presumably happens due to this piece of code in bfd_rx_hook() in proto/bfd/packets.c: s = bfd_find_session_by_addr(p, sk->faddr); I use fe80::1/fe80::2 as addresses for most of my IPv6 peering connections and sk->faddr is just a 128 bit value, so it contains no interface identifier, which likely leads to Bird confusing multiple BFD sessions. Regards, Julian

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[PATCH] babel: Set onlink flag for IPv4 routes with unreachable next hop
by Toke Høiland-Jørgensen 14 Apr '20

14 Apr '20

If the next hop of a route is not a reachable address, the route should be installed as onlink. This enables a configuration common in mesh networks where the mesh interface is assigned a /32 and babel handles the routing by installing onlink routes. Signed-off-by: Toke Høiland-Jørgensen <toke(a)toke.dk> --- proto/babel/babel.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/proto/babel/babel.c b/proto/babel/babel.c index 88c4711e..4fd88042 100644 --- a/proto/babel/babel.c +++ b/proto/babel/babel.c @@ -640,6 +640,13 @@ babel_announce_rte(struct babel_proto *p, struct babel_entry *e) .nh.iface = r->neigh->ifa->iface, }; + /* If we cannot find a reachable neighbour, set the entry to be onlink. This + * makes it possible to, e.g., assign /32 addresses on a mesh interface and + * have routing work. + */ + if (!neigh_find2(&p->p, &r->next_hop, r->neigh->ifa->iface, 0)) + a0.nh.flags = RNF_ONLINK; + rta *a = rta_lookup(&a0); rte *rte = rte_get_temp(a); rte->u.babel.seqno = r->seqno; -- 2.17.0

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Bird 1.6.3 removing IPv6 device routes on Linux (3.10.0)
by Ben Arblaster 12 Oct '19

12 Oct '19

Hi, I’m seeing an issue with bird 1.6.3 where IPv6 device routes are unexpectedly removed from the kernel table on Linux (3.10.0, CentOS 7) when bird removes a matching route learned via another protocol (in this case OSPF). To reproduce, I’ve rigged up a very simple test with two bird6 instances running OSPF in a single area 0 over a ptp tunnel. Configs are here - https://gist.github.com/andatche/ca5b5ac120e09b6b8171ec5ca95d2e25 If I add an address/network (e.g. fd00::1/64) to an interface (dummy0) on host A, the route is flooded by A, learned by B and correctly installed in the kernel table on B: fd00::/64 via fe80::5efe:ae2:b006 dev tun0 proto bird metric 1024 If I then add the same address/network (e.g. fd00::1/64) to an interface (dummy0) on host B, at that instant a device route is installed in the kernel table alongside the existing route on host B and it now looks like this: fd00::/64 dev dummy0 proto kernel metric 256 fd00::/64 via fe80::5efe:ae2:b006 dev tun0 proto bird metric 1024 Shortly after, bird picks up the new address/network on dummy0, recalculates the area and correctly selects the connected route as the new best. It then removes the old route via host A from the kernel table, as expected: kernel1 < removed fd00::/64 via fe80::5efe:ae2:b006 on tun0 However, this causes both the route via host A *and* the device route to be removed from the kernel table, leaving the kernel table on host B with no route to fd00::/64 at all. # ip -6 route show fd00::/64 # This is a change in behaviour from 1.4.5 and seems like a bug, rather than the expected behaviour? Regards, Ben -- Ben Arblaster e: ben(a)andatche.com t: +447943860840 w: https://andatche.com

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For developer, required some explanation on code with timer and BGP
by Mattia Milani 06 Apr '19

06 Apr '19

Hello all, this is a message for developer and who know how bird use timer, and buffer. Sorry for the length of this mail. For first, the protocol i want to modify and upgrade is BGP, i see that there isn't the timer MRAI implemented and it will be useful for some studies on information propagation, so i decided to develop a first version of it. The actual process to send any kind of pkt is to call the function bgp_fire_tx() and it's called by two other function respectively bgp_kick_tx() and bgp_tx() and the function bgp_fire_tx() take care to read from the buffer the message that has to be sent and send it. bgp_kick_tx() and bgp_tx() call bgp_fire_tx() while it don't return 0, so the clear all the buffer of the message that has to be sent. So my idea to introduce MRAI was that: Create a timer (for now I created it for connection, after like say RFC 4271 this timer has to be set for every route) and put it on the connection. Initialize it with the other timer of the conn when the state of the conn goes up i set it to some value and start the timer. when the timer finish i call the function MRAI_finish() that call the function bgp_fire_tx() while there is something to send more ore less like the while loop in bgp_kick_tx() and bgp_tx() when it's called bgp_fire_tx() on the update message part i written a check, if the timer isn't at 0 i can't send the update, because the function can be called from bgp_kick_tx() or bgp_tx(), but if it 0 it is finished so i can send the message When all the message had been send i reset the timer and start it again. But unfortunately i see something that doesn't make my code work. when something call bgp_kick_tx() or bgp_tx() the call bgp_fire_tx() and they clear all the buffer, including update message that wasn't sended so when the timer finish it didn't found anything on the buffer. Now how can i change that? My idea is to use a secondary buffer, when in bgp_fire_tx() i see that i can't send the update I will insert the pkt in this secondary buffer and consume the pkt on the main buffer. when bgp_kick_tx() or bgp_tx() have send all the messages I will transfer all the pkt in the secondary buffer into the main buffer. So I ask you it's possible that? there is something in the code already written that could help me? do you see another way to implement the MRAI timer? Thanks a lot to everyone, Mattia

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Add two bfd session with same dest ip and different local ip, can it work?
by bbk bbk 05 Nov '18

05 Nov '18

hi, Can the bird add two BFD sessions with same destination ip and different local ip? My testing is only one session can be added as if.

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bird logging
by Alexander Zubkov 29 Oct '18

29 Oct '18

Hi, When I specify relative log file path, the file is created relative to the current working directory. But for the include directive relative path are applied relative to the config file. Probably it would be better to have a consistent path resolution? I also suppose it could have been done intentionally. But I did not find description of this behaviour in the documentation. And I did not find anything on this question with google.

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[PATCH 2.x branch] BGP: Bind listen socket to VRF
by Alexander Zubkov 26 Oct '18

26 Oct '18

BGP protocol could not bind to the interface in a VRF even if the vrf option was specified in the configuration. Signed-off-by: Alexander Zubkov <green(a)qrator.net> --- proto/bgp/bgp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c index e7479df..3aa35ae 100644 --- a/proto/bgp/bgp.c +++ b/proto/bgp/bgp.c @@ -168,6 +168,7 @@ bgp_open(struct bgp_proto *p) sock *sk = sk_new(proto_pool); sk->type = SK_TCP_PASSIVE; + sk->vrf = p->p.vrf; sk->ttl = 255; sk->saddr = addr; sk->sport = port; -- 1.9.1

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segfault in bird v1.6.4
by Alexander Velkov 26 Oct '18

26 Oct '18

Hello bird-team, I have a bird v1.6.4. configuration that works fine. A certain set of actions leads to a segfault and a crash of the bird binary. I have configured and built bird 1.6.4. with IPv6 support that runs on a box with a i686 linux with kernel v4.14.75. My bird configuration: ### bird6.conf: protocol device { scan time 10; } protocol direct C_main { interface "*"; preference 255; check link; } protocol kernel K_main { preference 255; scan time 20; export all; learn; } include "*.conff"; ### ospfv3.conff in the same directory: debug protocols all; log syslog { info, remote, warning, error, auth, fatal, bug }; protocol ospf O_main { preference 145; instance id 0; area 172.16.0.0 { interface "vti0" { dead 120; hello 30; cost 1; priority 1; type pointopoint; neighbors { fe80::e68:3ff:fe26:5130; }; }; interface "eth1" { dead 40; hello 10; cost 1; priority 1; type broadcast; stub yes; }; }; import filter { accept; }; export filter { reject; }; } ### The following actions lead to a crash of bird6: EEPD[~]# /sbin/bird6 -P /var/run/bird6.pid -c /var/etc/bird6/bird6.conf Oct 24 14:23:08 EEPD info bird6 [ 4684]: Started EEPD[~]# ps | grep bird6 4930 root 1500 S /sbin/bird6 -P /var/run/bird6.pid -c /var/etc/bird6/bird6.conf 4932 root 1284 S grep bird6 EEPD[~]# EEPD[~]# ip -6 link add vti0 type vti6 local fd00::38 remote fd00::1b ikey 2 okey 2; EEPD[~]# ip -6 link set vti0 up; EEPD[~]# ifconfig vti0 mtu 1422 Oct 24 14:23:17 EEPD err bird6 [ 4684]: KIF: Received address message for unknown interface 33 Oct 24 14:23:20 EEPD err bird6 [ 4684]: O_main: Socket error on vti0: Invalid argument Oct 24 14:23:20 EEPD info kernel: [ 4684]: segfault at 58e ip b7eed103 sp bf9acad8 error 4 in libuClibc-1.0.30.so[b7ebd000+72000] EEPD[~]# EEPD[~]# ps | grep bird6 4988 root 1284 S grep bird6 EEPD[~]# ### Further testing - bird does NOT crash if the contents of bird6.conf and ospfv3.conf are placed in a single file without inclusion. - bird does NOT crash if the call 'ifconfig vti0 mtu 1422' is executed before 'ip -6 link set vti0 up'. Hope this information helps. Best Regards Alex

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BIRD 2.0.2 VPNv4 RD Filter
by Hombach, Tobias 25 Oct '18

25 Oct '18

Hi, Is it possible in current BIRD 2.0.2 release to filter (more dynamically) VPNv4 prefixes based on RD? In our scenario, we want to use BIRD to connect large VPNv4 landscapes and want to filter prefixes based on RD on Route Server ingress. I can extract RD from VPNv4 prefix with special operator '.rd' filter vpnv4_ingress { if (net.rd = 5000:200) then accept; reject; } This is working but I don't want 1x if-statement per RD as we have lots of RD's. Any ranges or wildcards are not allowed. Something like '5000:200..299' does not work. Or '5000:*' also does not work. I tried to create a constant for a VPNv4 prefix to use it in a filter: function some_function() prefix set test; { test = [ 0:5000:200 10.0.0.0/24 ]; } Also not allowed. Creating a constant of data type 'vpnrd' did not work. Then I tried to handle the output of 'net.rd' as string to maybe use shell pattern. filter vpnv4_ingress string test; { test = "5000:20?"; if net.rd ~ test then accept; reject; } Results in error: "<ERR> filters, line 90: ~ applied on unknown type pair". Changing the if-statement to 'if net.rd = test then accept;' does work w/o error but all prefixes are filtered. The shell pattern is not working. I guess the output of 'net.rd' is not a string. I also cannot save 'net.rd' output in a string variable. Last but not least. I have found a undocumented function 'format()'. This function seems to return a string and shell patterns work. I guess the function should not be used in production so I just used it for testing. define test = "5000:20?"; filter vpnv4_ingress { if format(net.rd) ~ test then accept; reject; } <TRACE> some-router > added [best] 5000:200 200.200.200.0/24 unicast But this works only once. As soon as I run 'configure' in BIRD client, BIRD does crash. <INFO> Reconfiguring <BUG> Unknown instruction 70 in same (F) Long story short. Is there a best practice to filter VPNv4 based on RD? Or anything on the roadmap? Filtering on RT with Communities works fine but does not fit our purpose. Thanks in advance! Regards Tobias

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