BGP not sending keepalives to specific IPv6 neighbor through GRE tunnel

[nioroso-x3]

Description

I am using FRR 7.3.1 in vyos 1.2.6, keepalives to a IPv6 neighbor over a GRE tunnel suddenly stopped being sent and the link flaps once the the other router doesnt receive the keepalives (cisco asr1001).

No one has touched this router in years, I tried rebooting and changing the timers to 240/30 in both routers and FRR continues with the same behavior.

` Message statistics:
Inq depth is 0
Outq depth is 2588
Sent Rcvd
Opens: 2 2
Notifications: 0 2
Updates: 824 6
Keepalives: 2 15
Route Refresh: 0 0
Capability: 0 0
Total: 828 25
Minimum time between advertisement runs is 0 seconds

For address family: IPv4 Unicast
Not part of any update group
Community attribute sent to this neighbor(all)
0 accepted prefixes

For address family: IPv6 Unicast
Update group 6, subgroup 7
Packet Queue length 0
Community attribute sent to this neighbor(all)
Inbound path policy configured
Outbound path policy configured
Incoming update prefix filter list is *asXXXXXnetV6
Outgoing update prefix filter list is *allroutesV6
3 accepted prefixes

Connections established 2; dropped 1
Last reset 00:00:25, Peer closed the session
`

The Keepalives sent counter only increments when a new session is established.

Version

vyos# show version 
FRRouting 7.3.1 (vyos).
Copyright 1996-2005 Kunihiro Ishiguro, et al.
configured with:
    '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--disable-silent-rules' '--libdir=${prefix}/lib/x86_64-linux-gnu' '--libexecdir=${prefix}/lib/x86_64-linux-gnu' '--disable-maintainer-mode' '--enable-exampledir=/usr/share/doc/frr/examples/' '--localstatedir=/var/run/frr' '--sbindir=/usr/lib/frr' '--sysconfdir=/etc/frr' '--with-vtysh-pager=/usr/bin/pager' '--libdir=/usr/lib/x86_64-linux-gnu/frr' '--with-moduledir=/usr/lib/x86_64-linux-gnu/frr/modules' '--disable-dependency-tracking' '--enable-systemd=yes' '--enable-rpki' '--with-libpam' '--enable-doc' '--enable-doc-html' '--enable-snmp' '--enable-fpm' '--disable-protobuf' '--disable-zeromq' '--enable-ospfapi' '--enable-bgp-vnc' '--enable-multipath=256' '--enable-user=frr' '--enable-group=frr' '--enable-vty-group=frrvty' '--enable-configfile-mask=0640' '--enable-logfile-mask=0640' 'build_alias=x86_64-linux-gnu' 'PYTHON=python3'

How to reproduce

I dont know how I would reproduce this in another configuration.

Expected behavior

For BGP keepalives to be sent.

Actual behavior

BGP keepalives are not being sent.

Additional context

No response

Checklist

• I have searched the open issues for this bug.
• I have not included sensitive information in this report.

[donaldsharp]

7.3 is just over 4 years ago at this point in time. While this might be a valid problem given the age of the code you are working with no-one is going to spend any time looking at this problem. I would recommend that you try to recreate this code on latest and let us know if the problem still exists, then we can look at it.