From 3dbe2b6061ba07711584a87b714e76da92c4f8fa Mon Sep 17 00:00:00 2001 From: Donald Sharp Date: Wed, 19 Feb 2020 10:52:14 -0500 Subject: [PATCH] bgpd: Add a better breadcrumb for when bgp is missconfiged Currently During bgp open collision resolution if both the router-id's are the same, we correctly follow the RFC and close the connection. The problem is of course that there is no notification of the error in configuration to the end user other than a subtle open debug message. Explicitly call out the miss-configuration as an error message as that this miss-config took several hours of debugging to notice. Signed-off-by: Donald Sharp --- bgpd/bgp_errors.c | 6 ++++++ bgpd/bgp_errors.h | 1 + bgpd/bgp_packet.c | 5 +++++ 3 files changed, 12 insertions(+) diff --git a/bgpd/bgp_errors.c b/bgpd/bgp_errors.c index d9aba87e35..8a33ce6789 100644 --- a/bgpd/bgp_errors.c +++ b/bgpd/bgp_errors.c @@ -456,6 +456,12 @@ static struct log_ref ferr_bgp_err[] = { .description = "As part of BGP startup, the peer and ourselves can start connections to each other at the same time. During this process BGP received additional configuration, but it was only applied to one of the two nascent connections. Depending on the result of collision detection and resolution this configuration might be lost. To remedy this, after performing collision detection and resolution the peer session has been reset in order to apply the new configuration.", .suggestion = "Gather data and open a Issue so that this developmental escape can be fixed, the peer should have been reset", }, + { + .code = EC_BGP_ROUTER_ID_SAME, + .title = "BGP has detected a duplicate router id during collision resolution", + .description = "As part of normal collision detection for opening a connection to a peer, BGP has detected that the remote peer's router-id is the same as ours", + .suggestion = "Change one of the two router-id's", + }, { .code = END_FERR, } diff --git a/bgpd/bgp_errors.h b/bgpd/bgp_errors.h index 35c5cc3998..49c58ae6b0 100644 --- a/bgpd/bgp_errors.h +++ b/bgpd/bgp_errors.h @@ -98,6 +98,7 @@ enum bgp_log_refs { EC_BGP_CAPABILITY_UNKNOWN, EC_BGP_INVALID_NEXTHOP_LENGTH, EC_BGP_DOPPELGANGER_CONFIG, + EC_BGP_ROUTER_ID_SAME, }; extern void bgp_error_init(void); diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c index c72f7226e2..9d030378c7 100644 --- a/bgpd/bgp_packet.c +++ b/bgpd/bgp_packet.c @@ -1007,6 +1007,11 @@ static int bgp_collision_detect(struct peer *new, struct in_addr remote_id) return -1; } else { + if (ntohl(peer->local_id.s_addr) == + ntohl(remote_id.s_addr)) + flog_err(EC_BGP_ROUTER_ID_SAME, "Peer's router-id %s is the same as ours", + inet_ntoa(remote_id)); + /* 3. Otherwise, the local system closes newly created BGP connection (the one associated with the