Failed to establish bgp peer between confederations.

[wangdan1323]

Description

When a confederation is configured and peers between the confederations are added to the group, the peers between the confederations fails to be established.

Version

FRR Version: stable/8.5

How to reproduce

A:
router bgp 63
bgp router-id 1.1.1.63
no bgp ebgp-requires-policy
no bgp default ipv4-unicast
bgp confederation identifier 65535.63
bgp confederation peers 63 92
neighbor rap peer-group
neighbor rap remote-as 65535.65530
neighbor rap description connect_to_leaf
neighbor rap advertisement-interval 0
neighbor rap timers 30 90
neighbor rap timers connect 30
neighbor 30.0.0.2 peer-group rap
!
address-family ipv4 unicast
neighbor rap activate
exit-address-family

B：
router bgp 65535.65530
bgp router-id 1.1.1.51
no bgp ebgp-requires-policy
no bgp default ipv4-unicast
bgp med peer-up 150 200
neighbor rap peer-group
neighbor rap remote-as 65535.63
neighbor rap description connect_to_leaf
neighbor rap advertisement-interval 0
neighbor rap timers 30 90
neighbor rap timers connect 30
neighbor 30.0.0.1 peer-group rap
!
address-family ipv4 unicast
neighbor rap activate
exit-address-family

Expected behavior

A and B succeeded to establish a bgp peer.

Actual behavior

A and B failed to establish a bgp peer.
On B;
adminadmin@sonic-51:~# show ip bgp neighbors 30.0.0.1
BGP neighbor is 30.0.0.1, remote AS 65535.63, local AS 65535.65530, external link
Hostname: sonic-63
Member of peer-group rap for session parameters
BGP version 4, remote router ID 1.1.1.63, local router ID 1.1.1.51
BGP state = Idle
Last read 00:06:22, Last write 00:00:15
Hold time is 90, keepalive interval is 30 seconds
Configured hold time is 90, keepalive interval is 30 seconds
Graceful restart information:
Local GR Mode: Restart*
Remote GR Mode: NotApplicable
R bit: False
Timers:
Configured Restart Time(sec): 300
Received Restart Time(sec): 300
Message statistics:
Inq depth is 0
Outq depth is 0
Sent Rcvd
Opens: 12 9
Notifications: 14 2
Updates: 2 2
Keepalives: 472 472
Route Refresh: 0 0
Capability: 0 0
Total: 500 485
Minimum time between advertisement runs is 0 seconds

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

Connections established 2; dropped 2
Last reset 00:06:21, Notification sent (OPEN Message Error/Bad Peer AS)
Message received that caused BGP to send a NOTIFICATION:
FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF
00550104 003F005A 0101013F 38020601
04000100 01020280 00020202 00020641
04000000 3F020645 04000101 01020C49
0A08736F 6E69632D 36330002 08400601
2C000101 80
Local host: 30.0.0.2, Local port: 53508
Foreign host: 30.0.0.1, Foreign port: 179
Nexthop: 30.0.0.2
Nexthop global: fe80::9a19:2cff:fe5b:d110
Nexthop local: fe80::9a19:2cff:fe5b:d110
BGP connection: shared network
BGP Connect Retry Timer in Seconds: 30
Next start timer due in 105 seconds
Read thread: off Write thread: off FD used: -1

Additional context

A's open message used wrong as 63.
If the BGP group is not used, the bgp peer is successfully established.

Checklist

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

[ton31337]

Please try the latest versions.