multi: make ProofMatureDelta configurable

We add a new config option to set the `ProofMatureDelta` so the users
can tune their graphs based on their own perference over the num of
confs found in the announcement signatures.

config.go

@@ -694,6 +694,7 @@ func DefaultConfig() Config {
 			MaxChannelUpdateBurst: discovery.DefaultMaxChannelUpdateBurst,
 			ChannelUpdateInterval: discovery.DefaultChannelUpdateInterval,
 			SubBatchDelay:         discovery.DefaultSubBatchDelay,
+			AnnouncementConf:      discovery.DefaultProofMatureDelta,
 		},
 		Invoices: &lncfg.Invoices{
 			HoldExpiryDelta: lncfg.DefaultHoldInvoiceExpiryDelta,
@@ -1754,6 +1755,7 @@ func ValidateConfig(cfg Config, interceptor signal.Interceptor, fileParser,
 		cfg.Invoices,
 		cfg.Routing,
 		cfg.Pprof,
+		cfg.Gossip,
 	)
 	if err != nil {
 		return nil, err

discovery/gossiper.go

@@ -62,6 +62,11 @@ const (
 	// we'll maintain. This is the global size across all peers. We'll
 	// allocate ~3 MB max to the cache.
 	maxRejectedUpdates = 10_000
+
+	// DefaultProofMatureDelta specifies the default value used for
+	// ProofMatureDelta, which is the number of confirmations needed before
+	// processing the announcement signatures.
+	DefaultProofMatureDelta = 6
 )
 
 var (
@@ -1984,10 +1989,12 @@ func (d *AuthenticatedGossiper) addNode(msg *lnwire.NodeAnnouncement,
 // NOTE: must be used inside a lock.
 func (d *AuthenticatedGossiper) isPremature(chanID lnwire.ShortChannelID,
 	delta uint32, msg *networkMsg) bool {
-	// TODO(roasbeef) make height delta 6
-	//  * or configurable
 
-	msgHeight := chanID.BlockHeight + delta
+	// The channel is already confirmed at chanID.BlockHeight so we minus
+	// one block. For instance, if the required confirmation for this
+	// channel announcement is 6, we then only need to wait for 5 more
+	// blocks once the funding tx is confirmed.
+	msgHeight := chanID.BlockHeight + delta - 1
 
 	// The message height is smaller or equal to our best known height,
 	// thus the message is mature.

docs/release-notes/release-notes-0.19.0.md

@@ -160,6 +160,10 @@
   range TLVs provided with the existing set of records on the HTLC,
   overwriting any conflicting values with those supplied by the API.
 
+* [Make](https://github.com/lightningnetwork/lnd/pull/9405) the param
+`ProofMatureDelta` used in gossip to be configurable via
+`--gossip.announcement-conf`, with a default value of 5.
+
 ## lncli Updates
 
 ## Code Health
@@ -204,6 +208,7 @@ config option](https://github.com/lightningnetwork/lnd/pull/9182) and introduce
 a new option `channel-max-fee-exposure` which is unambiguous in its description.
 The underlying functionality between those two options remain the same.
 
+
 ## Breaking Changes
 ## Performance Improvements
 

lncfg/gossip.go

@@ -1,6 +1,7 @@
 package lncfg
 
 import (
+	"fmt"
 	"time"
 
 	"github.com/lightningnetwork/lnd/discovery"
@@ -18,6 +19,8 @@ type Gossip struct {
 	ChannelUpdateInterval time.Duration `long:"channel-update-interval" description:"The interval used to determine how often lnd should allow a burst of new updates for a specific channel and direction."`
 
 	SubBatchDelay time.Duration `long:"sub-batch-delay" description:"The duration to wait before sending the next announcement batch if there are multiple. Use a small value if there are a lot announcements and they need to be broadcast quickly."`
+
+	AnnouncementConf uint32 `long:"announcement-conf" description:"The number of confirmations required before processing channel announcements."`
 }
 
 // Parse the pubkeys for the pinned syncers.
@@ -35,3 +38,17 @@ func (g *Gossip) Parse() error {
 
 	return nil
 }
+
+// Validate checks the Gossip configuration to ensure that the input values are
+// sane.
+func (g *Gossip) Validate() error {
+	if g.AnnouncementConf <= 3 {
+		return fmt.Errorf("announcement-conf=%v must be no less than 3",
+			g.AnnouncementConf)
+	}
+
+	return nil
+}
+
+// Compile-time constraint to ensure Gossip implements the Validator interface.
+var _ Validator = (*Gossip)(nil)

sample-lnd.conf

@@ -1729,6 +1729,8 @@
 ; be broadcast quickly.
 ; gossip.sub-batch-delay=5s
 
+; The number of confirmations required before processing channel announcements.
+; gossip.announcement-conf=6
 
 [invoices]
 

server.go

@@ -1118,7 +1118,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 
 			return s.genNodeAnnouncement(nil)
 		},
-		ProofMatureDelta:        0,
+		ProofMatureDelta:        cfg.Gossip.AnnouncementConf,
 		TrickleDelay:            time.Millisecond * time.Duration(cfg.TrickleDelay),
 		RetransmitTicker:        ticker.New(time.Minute * 30),
 		RebroadcastInterval:     time.Hour * 24,