Here we have an unsual confederations config, "router bgp X" and

Here we have an unsual confederations config, "router bgp X" and
"bgp confederation id X" are the same value.

router bgp 1
 bgp router-id 10.1.1.1
 bgp confederation identifier 1
 bgp confederation peers 24 35
 neighbor 10.1.1.2 remote-as 24
 neighbor 10.1.1.2 update-source lo
 neighbor 10.1.1.3 remote-as 1
 neighbor 10.1.1.3 update-source lo

The customer does this because they want to peer to 10.1.1.2 as a
confed-external peer but peer with 10.1.1.3 as a normal iBGP peer.

The bug was that we thought 10.1.1.3 was an EBGP peer so we did not send him
LOCALPREF which caused the Juniper to send us a NOTIFICATION. I confirmed
that quagga also sends a NOTIFICATION in this scenario.

The fix is to add a check to see if router bgp X and bgp confederation
identifier X are equal because that is a factor in determining if a peer is
EBGP or IBGP

Additional issues fixed in the this patch:

  We were not properly removing all AS_CONFED_SEQUENCEs/SETs from the aspath
  when advertising a route to an ebgp peer. This was due to two issues:

    We only called aspath_delete_confed_seq() if confederations were
    configured.  We can RX as aspath with CONFED segments even if
    confederations are not configured.

    aspath_delete_confed_seq() was implemented based on the original confed
    RFC 3065 which basically said "remove all of the leading
    AS_CONFED_SEQUENCEs/SETs" where the new confed RFC 5065 says "remove ALL
    of the AS_CONFED_SEQUENCEs/SETs"

  peer-groups did not work for confed-external peers. peer_calc_sort() always
  returned BGP_PEER_EBGP for a confederations where the remote-as was not
  specified. The reason was the peer->as_type was AS_UNSPECIFIED but we checked

    if (peer->as_type != AS_SPECIFIED)
       return (peer->as_type == AS_INTERNAL ? BGP_PEER_IBGP : BGP_PEER_EBGP);

    After fixing that I found that when we got to the else where we checked for
    peer1 we could only possibly return BGP_PEER_IBGP or BGP_PEER_EBGP, we need
    to also be able to return BGP_PEER_CONFED. I changed this to return
    peer1->sort.

  "show ip bgp x.x.x.x" would always display "Local" for the aspath. This is
  because we were calling aspath_counts_hop() to determine if the aspath was
  empty. This is wrong though because CONFED segments do not count towards
  aspath hopcount. The fix is to null check aspath->segments to determine if
  the aspath is actually empty.

  "show ip bgp x.x.x.x" and "show ip bgp neighbor" always displayed
  "internal" or "external" and never "confed-internal" or "confed-external".
  This made troubleshooting difficult because I couldn't tell exactly what
  kind of peer I was dealing with. I added the confed-internal and
  confed-external output...also added a "peer-type" field in the json output
  for 'show ip bgp x.x.x.x'

  "show ip bgp peer-group" did not list the peer-group name if we hadn't
  determined the "type" (internal, external, etc) for the peer-group