mirror/osrg-gobgp
1
0
Fork 0
mirror of https://github.com/osrg/gobgp.git synced 2024-05-11 05:55:10 +00:00
Code Issues Releases Activity

fix graceful-restart when not all peers are restarting

Browse Source 
This fixes an issue where GoBGP would incorrectly defer sending routes to a peer on a graceful restart.
RFC4724 states:

> Once the session between the Restarting Speaker and the Receiving
> Speaker is re-established, the Restarting Speaker will receive and
> process BGP messages from its peers.  However, it MUST defer route
> selection for an address family until it either (a) receives the
> End-of-RIB marker from all its peers (excluding the ones with the
> "Restart State" bit set in the received capability and excluding the
> ones that do not advertise the graceful restart capability) or (b)
> the Selection_Deferral_Timer referred to below has expired.

The scenario that this fixes is where you have 3 (or more) peers, and 2 of the peers ("A" and "B") perform a graceful restart at the same time, but the 3rd ("C") does not. If after restart peer C sends EOR to peer A before peer B reaches BGP_FSM_ESTABLISHED with peer A, it defers the route selection. However once peer B does reach BGP_FSM_ESTABLISHED, peer A still wouldn't send any updates to peer C until the deferral expired.

This commit changes the behavior so that upon restart, once the peer receives EOR from all non-restarting peers and reaches BGP_FSM_ESTABLISHED for all restarting peers, the routes are sent to all peers.
This commit is contained in:
Patrick Hemmer
2018-05-22 22:01:28 +09:00
committed by FUJITA Tomonori
parent 8c453bc936
commit 9c8b20a2ef
2 changed files with 40 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files
server/fsm.go
+4 -2
View File
@@ -1163,8 +1163,10 @@ func (h *FSMHandler) opensent() (bgp.FSMState, FsmStateReason) {
"Topic": "Peer",
"Key": fsm.pConf.State.NeighborAddress,
"State": fsm.state.String(),
}).Debug("peer is restarting, skipping sync process")
fsm.pConf.GracefulRestart.State.LocalRestarting = false
}).Debug("peer has restarted, skipping wait for EOR")
for i := range fsm.pConf.AfiSafis {
fsm.pConf.AfiSafis[i].MpGracefulRestart.State.EndOfRibReceived = true
}
}
if fsm.pConf.GracefulRestart.Config.NotificationEnabled && cap.Flags&0x04 > 0 {
fsm.pConf.GracefulRestart.State.NotificationEnabled = true
server/server.go
+36 -10
View File
@@ -1156,16 +1156,42 @@ func (server *BgpServer) handleFSMMessage(peer *Peer, e *FsmMsg) {
} else {
// RFC 4724 4.1
// Once the session between the Restarting Speaker and the Receiving
// Speaker is re-established, the Restarting Speaker will receive and
// process BGP messages from its peers. However, it MUST defer route
// selection for an address family until it either (a) ...snip...
// or (b) the Selection_Deferral_Timer referred to below has expired.
deferral := peer.fsm.pConf.GracefulRestart.Config.DeferralTime
log.WithFields(log.Fields{
"Topic": "Peer",
"Key": peer.ID(),
}).Debugf("Now syncing, suppress sending updates. start deferral timer(%d)", deferral)
time.AfterFunc(time.Second*time.Duration(deferral), deferralExpiredFunc(bgp.RouteFamily(0)))
// Speaker is re-established, ...snip... it MUST defer route
// selection for an address family until it either (a) receives the
// End-of-RIB marker from all its peers (excluding the ones with the
// "Restart State" bit set in the received capability and excluding the
// ones that do not advertise the graceful restart capability) or (b)
// the Selection_Deferral_Timer referred to below has expired.
allEnd := func() bool {
for _, p := range server.neighborMap {
if !p.recvedAllEOR() {
return false
}
}
return true
}()
if allEnd {
for _, p := range server.neighborMap {
p.fsm.pConf.GracefulRestart.State.LocalRestarting = false
if !p.isGracefulRestartEnabled() {
continue
}
paths, _ := server.getBestFromLocal(p, p.configuredRFlist())
if len(paths) > 0 {
sendFsmOutgoingMsg(p, paths, nil, false)
}
}
log.WithFields(log.Fields{
"Topic": "Server",
}).Info("sync finished")
} else {
deferral := peer.fsm.pConf.GracefulRestart.Config.DeferralTime
log.WithFields(log.Fields{
"Topic": "Peer",
"Key": peer.ID(),
}).Debugf("Now syncing, suppress sending updates. start deferral timer(%d)", deferral)
time.AfterFunc(time.Second*time.Duration(deferral), deferralExpiredFunc(bgp.RouteFamily(0)))
}
}
} else {
if server.shutdown && nextState == bgp.BGP_FSM_IDLE {