mirrors/bird
mirrors/bird
0
0
Fork 0
mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-12-22 09:41:54 +00:00
Code Releases Activity

BGP: AS-wide unique router ID (RFC 6286) support

Browse Source 
RFC 6286 relaxed rules for router IDs, allowing EBGP sessions between
routers with the same ID (but different ASN).
This commit is contained in:
Ondrej Zajicek 2015-03-29 21:24:47 +02:00
parent 9aed29e605
commit 2eadd36fa0
1 changed files with 19 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
proto/bgp/packets.c
View File

@ -943,7 +943,8 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
if (hold > 0 && hold < 3)
{ bgp_error(conn, 2, 6, pkt+22, 2); return; }
if (!id || id == 0xffffffff || id == p->local_id)
/* RFC 6286 2.2 - router ID is nonzero and AS-wide unique */
if (!id || (p->is_internal && id == p->local_id))
{ bgp_error(conn, 2, 3, pkt+24, -4); return; }
if ((conn->advertised_as != base_as) && (base_as != AS_TRANS))
@ -978,8 +979,23 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, int len)
break;
case BS_OPENCONFIRM:
if ((p->local_id < id) == (conn == &p->incoming_conn))
{
/*
* Description of collision detection rules in RFC 4271 is confusing and
* contradictory, but it is essentially:
*
* 1. Router with higher ID is dominant
* 2. If both have the same ID, router with higher ASN is dominant [RFC6286]
* 3. When both connections are in OpenConfirm state, one initiated by
* the dominant router is kept.
*
* The first line in the expression below evaluates whether the neighbor
* is dominant, the second line whether the new connection was initiated
* by the neighbor. If both are true (or both are false), we keep the new
* connection, otherwise we keep the old one.
*/
if (((p->local_id < id) || ((p->local_id == id) && (p->local_as < p->remote_as)))
== (conn == &p->incoming_conn))
{
/* Should close the other connection */
BGP_TRACE(D_EVENTS, "Connection collision, giving up the other connection");
bgp_error(other, 6, 7, NULL, 0);