- Bird-users - Mailing Lists

[PATCH] BGP: Log value of invalid NEXT_HOP in bgp_apply_next_hop()
by Simon Ruderich 15 Dec '21

15 Dec '21

--- Hello, while debugging "Invalid NEXT_HOP attribute" messages in my setup I had to recompile bird2 with additional debug output to determine which BAD_NEXT_HOP line was triggered and with which NEXT_HOP value. After adding this patch determining the problem was very easy. I also looked at the other BAD_NEXT_HOP in the file but I'm not sure how to properly print their values. Regards Simon proto/bgp/packets.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c index 99b5d5b4..830a2060 100644 --- a/proto/bgp/packets.c +++ b/proto/bgp/packets.c @@ -955,7 +955,7 @@ bgp_apply_next_hop(struct bgp_parse_state *s, rta *a, ip_addr gw, ip_addr ll) nbr = neigh_find(&p->p, ll, p->neigh->iface, 0); if (!nbr || (nbr->scope == SCOPE_HOST)) - WITHDRAW(BAD_NEXT_HOP); + WITHDRAW(BAD_NEXT_HOP " %I (direct)", gw); a->dest = RTD_UNICAST; a->nh.gw = nbr->addr; @@ -965,7 +965,7 @@ bgp_apply_next_hop(struct bgp_parse_state *s, rta *a, ip_addr gw, ip_addr ll) else /* GW_RECURSIVE */ { if (ipa_zero(gw)) - WITHDRAW(BAD_NEXT_HOP); + WITHDRAW(BAD_NEXT_HOP " %I (recursive)", gw); rtable *tab = ipa_is_ip4(gw) ? c->igp_table_ip4 : c->igp_table_ip6; s->hostentry = rt_get_hostentry(tab, gw, ll, c->c.table); -- 2.34.1 -- + privacy is necessary + using gnupg http://gnupg.org + public key id: 0x92FEFDB7E44C32F9

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OSPF/general question: Using v6 next-hop for v4 routes
by Sebastian Hahn 10 Dec '21

10 Dec '21

Hi there, I've been trying to remove v4 transit nets from my setup. This seems to work well for BGP (both eBGP and iBGP) - I have routes for all external v4 addresses with the appropriate next hop set. For my internal routing, I'm using OSPF, but it seems OSPF does not allow v6 next hops for v4 routes. Checking RFC 5838 seems to imply that this is a general design choice for OSPF, but I am not sure if my reading is correct. Also, are there any practical drawbacks for this kind of setup that I may have missed when choosing it for BGP? Thanks, also for any pointers how to achieve the intended setup! Sebastian

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how to do IPv6 address assignment (eBGP --> iBGP --> home/lan)
by Nicolas Embriz 01 Dec '21

01 Dec '21

Hi, I manage to configure, establish a session and announce my prefix with this configuration: --- log "/var/log/bird.log" all; router id <ipv4>; define MYAS = 1234; protocol device { scan time 10; } protocol direct { ipv6; interface "dummy*"; } # templates template bgp uplink { local as MYAS; ipv6 { import all; export filter { if net = <ipv6::/44> then accept; reject; }; }; graceful restart on; } protocol bgp SBv6 from uplink { neighbor <ipv6> a as 12345; source address <myipvy>; } --- For testing I added to eth0 an IPv6 address alias belonging to my /44 segment, I was available to ping and so far all good, but now something that I am struggling with (probably something very basic) is how to do IP address assignment to my network from the router? This router is a VM but I would like to know how I could use a /64 subnet and assign IP's to my home network. Probably I am following the wrong approach, but I wanted to give a try creating an internal router (iBGP) and announce only the /64 subnet, I am using wireguard to connect the VM's but can't find a way to ping any IP I assign in this VM, something like this (internet) | | ( VM eBGP/44 ) <--- Wireguard ---> (VM iBGP/64) <----> HOME/LAN (/64) this is my config: log "/var/log/bird.log" all; router id <ipv4>; define MYAS = 1234; protocol device { scan time 10; } protocol direct { ipv6; interface "dummy*"; } template bgp iAS { local as MYAS; ipv6 { import all; export filter { if net = <ipv6::/64> then accept; reject; }; }; graceful restart on; } protocol bgp iBGP from iAS { debug all; neighbor <peer wireguard ipv6>%wg0 as MYAS; direct; source address <wireguard ipv6>; } The session gets established but only from the eBGP I can ping the iBGP but not the other way around or from other hosts. Probably I may be over-complicating things, and I could do everything from the main router but is that the case, still wondering how can I then start to assign IPv6's address to my home network? should I configure something like radvd so that my devices can claim an IPv6? I am doing this just for learning purposes, so if there is a better way or practice to follow let me know. regards.

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Quick suggestion about enable/disable protocol
by bird21＠sensation.net.au 01 Dec '21

01 Dec '21

Hi, Is this list the place to discuss feature requests? Please let me know if there's somewhere more appropriate. Re enable/disable <prot> available in CLI, but not config: 1. Allow enable/disable to be part of the config, so that a protocol can be disabled by default, and needs a manual poke via CLI command to enable it. For example, a backup session that will only be enabled when the main link is down. 2a. When reloading config, preserve the current state of a protocol that has been disabled. (I'm trying to debug a config, which involves disabling a particular BGP session, but every time I reload config BIRD re-enables the session.) 2b. An explicit "enable" directive in config (see #1) could also be used to make it clear that a reload *should* enable this protocol regardless of its previous state. Thanks!

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BGP perf tests with filters
by Justin Pietsch 30 Nov '21

30 Nov '21

Hi, I've written a new blog post on BGP performance testing, this time using filters. https://elegantnetwork.github.io/posts/bgperf-first-try-at-filtering/. Let me know how I could make this better and more representative. thanks, Justin

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Displayed update timestamps vary by 1 second for the exact same update
by bird21＠sensation.net.au 26 Nov '21

26 Nov '21

Hi all, If I do several consecutive "show route" queries, the timestamp keeps changing back and forth, by about a second. Example: 0.0.0.0/0 via x.x.x.x on em2.100 [aapt 05:20:28] * (100) [AS2764i] 0.0.0.0/0 via x.x.x.x on em2.100 [aapt 05:20:28] * (100) [AS2764i] 0.0.0.0/0 via x.x.x.x on em2.100 [aapt 05:20:27] * (100) [AS2764i] 0.0.0.0/0 via x.x.x.x on em2.100 [aapt 05:20:28] * (100) [AS2764i] I notice (via public route servers) that Quagga and FRRouting seem to do the same thing. Example: Last update: Thu Nov 25 18:20:31 2021 Last update: Thu Nov 25 18:20:30 2021 Last update: Thu Nov 25 18:20:30 2021 Last update: Thu Nov 25 18:20:31 2021 Does Bird do this in order emulate some convention (like perhaps something Cisco has done for decades), or is there some other reason it's displaying an inconsistent timestamp? I have a script that compares the md5 of the current output with the previous minute to decide whether to log the routing table, but because of this quirk the md5 changes almost every time... So, is this a bug, or feature? :) And is there some other reliable way to determine that Bird's routing table has changed? Thanks.

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Use presence of route to enable/disable BGP session
by bird21＠sensation.net.au 25 Nov '21

25 Nov '21

Hi all, I want to enable a backup BGP session (or perhaps, keep the session up and change the import/export filters) only when the main peer goes down (default disappears) Conceptually, I want to do something like this: if net = 0.0.0.0/0 then { if from = x.x.x.x then { # x.x.x.x = main peer disable backup_bgp_session; } else { enable backup_bgp_session; } } Obviously this doesn't work, since disable/enable cannot be used in the config. The logic is also a little flawed. I thought about setting a global variable in one filter, and using that variable in another to decide what to export to the backup peer, but it seems that BIRD only supports local variables? I can fudge it by using an external script to query "birdc show route 0.0.0.0/0" to check for the presense of default, and then "birdc enable backup_bgp_session" or "birdc disable backup_bgp_session" as appropriate, but I'd prefer to be able to do it within BIRD. Hope someone can give me some hints. Thanks.

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bird-2.0.8 in Debian bullseye-backports
by Jakub Ružička 15 Nov '21

15 Nov '21

Hello Community, latest bird2-2.0.8 is now available from Debian bullseye-backports \o/ HOWTO get on Debian bullseye: echo "deb http://deb.debian.org/debian bullseye-backports main contrib" >> /etc/apt/sources.list apt update apt -t bullseye-backports install bird2 Cheers, Jakub Ružička CZ.NIC packager 📦

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[PATCH] doc: bgp: remove "advertise ipv4"
by Simon Ruderich 13 Nov '21

13 Nov '21

The option was removed in d15b0b0a ("BGP redesign", 2016-12-07) but the documentation wasn't updated. --- doc/bird.sgml | 7 ------- 1 file changed, 7 deletions(-) diff --git a/doc/bird.sgml b/doc/bird.sgml index 39dadaf2..4e4804de 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -2607,13 +2607,6 @@ using the following configuration parameters: disabled. Default: on, with automatic fallback to off when received capability-related error. - <tag><label id="bgp-advertise-ipv4">advertise ipv4 <m/switch/</tag> - Advertise IPv4 multiprotocol capability. This is not a correct behavior - according to the strict interpretation of <rfc id="4760">, but it is - widespread and required by some BGP implementations (Cisco and Quagga). - This option is relevant to IPv4 mode with enabled capability - advertisement only. Default: on. - <tag><label id="bgp-advertise-hostname">advertise hostname <m/switch/</tag> Advertise hostname capability along with the hostname. Default: off. -- 2.33.1 -- + privacy is necessary + using gnupg http://gnupg.org + public key id: 0x92FEFDB7E44C32F9

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Contributing to BIRD
by Jan Prukner 13 Nov '21

13 Nov '21

Hello everybody, my name is Jan, I am a backend developer. I'd like to get to know BIRD's codebase. My main motivation is to improve my C language skills. I used BIRD some time ago and am interested in networking. I started reading the Coder's Doc 2.0. Do you accept contributions from people outside of CZ.NIC? If you do, what one can do to contribute? Any tasks suitable for newcommers? Cheers Jan

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