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Identify a live route by prefix and peer (closes #55)
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A peer has at most one route per prefix, but both live route tables were
unique on prefix, origin AS and peer. A peer that changed a prefix's origin
AS left its old route behind, and a withdrawal sent in the same message as
announcements was given their origin AS and missed the withdrawn route.

Both tables are now unique on prefix and peer. An announcement replaces the
peer's row for the prefix, origin AS included; a withdrawal deletes it
without looking at an origin AS. The route counts and prefix distribution
kept in memory stay exact, for IPv4 and IPv6.

Model: opus-5-5
This commit was merged in pull request #82.
This commit is contained in:
clawbot
2026-10-19 09:13:25 +02:00
parent e0b9c2685f
commit f7c88c2496
9 changed files with 236 additions and 153 deletions
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internal/routewatch/prefixhandler.go
+14 -42
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@@ -108,14 +108,14 @@ func (h *PrefixHandler) HandleMessage(msg *ristypes.RISMessage) {
// Withdrawals are queued before announcements, because the batch keeps
// each peer's last update for a prefix: a message that lists a prefix as
// both withdrawn and announced keeps the route (RFC 4271 section 4.3).
// A withdrawal names only the prefix and peer: the message's AS path, and
// so its origin AS, belongs to the announced prefixes.
for _, prefix := range msg.Withdrawals {
h.batch = append(h.batch, prefixUpdate{
prefix: canonicalPrefix(prefix),
originASN: originASN, // Use the originASN from path if available
peer: msg.Peer,
messageType: "withdrawal",
timestamp: timestamp,
path: msg.Path,
})
// Record withdrawal in metrics
if h.metrics != nil {
@@ -221,7 +221,6 @@ func (h *PrefixHandler) flushBatchLocked() {
// Create deletion record for batch delete
routesToDelete = append(routesToDelete, database.LiveRouteDeletion{
Prefix: update.prefix,
OriginASN: update.originASN,
PeerIP: update.peer,
IPVersion: ipVersion,
})
@@ -425,51 +424,24 @@ func (h *PrefixHandler) processAnnouncementDirect(update prefixUpdate) {
// processWithdrawalDirect handles removing a route directly without prefix table
// nolint:unused // kept for potential future use
func (h *PrefixHandler) processWithdrawalDirect(update prefixUpdate) {
// For withdrawals, we need to delete the route from live_routes
if update.originASN > 0 {
if err := h.db.DeleteLiveRoute(update.prefix, update.originASN, update.peer); err != nil {
h.logger.Error("Failed to delete live route",
"prefix", update.prefix,
"origin_asn", update.originASN,
"peer", update.peer,
"error", err,
)
}
} else {
// If no origin ASN, just delete all routes for this prefix from this peer
if err := h.db.DeleteLiveRoute(update.prefix, 0, update.peer); err != nil {
h.logger.Error("Failed to delete live route (no origin ASN)",
"prefix", update.prefix,
"peer", update.peer,
"error", err,
)
}
if err := h.db.DeleteLiveRoute(update.prefix, update.peer); err != nil {
h.logger.Error("Failed to delete live route",
"prefix", update.prefix,
"peer", update.peer,
"error", err,
)
}
}
// processWithdrawal handles removing a route from the live routing table
// nolint:unused // kept for potential future use
func (h *PrefixHandler) processWithdrawal(_ *database.Prefix, update prefixUpdate) {
// For withdrawals, we need to delete the route from live_routes
// Since we have the origin ASN from the update, we can delete the specific route
if update.originASN > 0 {
if err := h.db.DeleteLiveRoute(update.prefix, update.originASN, update.peer); err != nil {
h.logger.Error("Failed to delete live route",
"prefix", update.prefix,
"origin_asn", update.originASN,
"peer", update.peer,
"error", err,
)
}
} else {
// If no origin ASN, just delete all routes for this prefix from this peer
if err := h.db.DeleteLiveRoute(update.prefix, 0, update.peer); err != nil {
h.logger.Error("Failed to delete live route (no origin ASN)",
"prefix", update.prefix,
"peer", update.peer,
"error", err,
)
}
if err := h.db.DeleteLiveRoute(update.prefix, update.peer); err != nil {
h.logger.Error("Failed to delete live route",
"prefix", update.prefix,
"peer", update.peer,
"error", err,
)
}
}