config: add new --v2transport option to gate BIP 324

config.go

@@ -177,6 +177,7 @@ type config struct {
 	TrickleInterval      time.Duration `long:"trickleinterval" description:"Minimum time between attempts to send new inventory to a connected peer"`
 	UtxoCacheMaxSizeMiB  uint          `long:"utxocachemaxsize" description:"The maximum size in MiB of the UTXO cache"`
 	TxIndex              bool          `long:"txindex" description:"Maintain a full hash-based transaction index which makes all transactions available via the getrawtransaction RPC"`
+	V2Transport          bool          `long:"v2transport" description:"Enable P2P v2 encrypted transport protocol (BIP324) (default: false)"`
 	UserAgentComments    []string      `long:"uacomment" description:"Comment to add to the user agent -- See BIP 14 for more information."`
 	Upnp                 bool          `long:"upnp" description:"Use UPnP to map our listening port outside of NAT"`
 	ShowVersion          bool          `short:"V" long:"version" description:"Display version information and exit"`
@@ -442,6 +443,7 @@ func loadConfig() (*config, []string, error) {
 		Generate:             defaultGenerate,
 		TxIndex:              defaultTxIndex,
 		AddrIndex:            defaultAddrIndex,
+		V2Transport:          false,
 	}
 
 	// Service options which are only added on Windows.

sample-btcd.conf

@@ -176,6 +176,11 @@
 ; Disable committed peer filtering (CF).
 ; nocfilters=1
 
+; Enable or disable the P2P v2 encrypted transport protocol (BIP324).
+; If disabled (which is the default), btcd will only attempt to use the
+; v1 P2P protocol. (default: 0)
+; v2transport=0
+
 ; ------------------------------------------------------------------------------
 ; RPC server options - The following options control the built-in RPC server
 ; which is used to control and query information from a running btcd process.

server.go

@@ -2182,7 +2182,7 @@ func newPeerConfig(sp *serverPeer) *peer.Config {
 		ProtocolVersion:     peer.MaxProtocolVersion,
 		TrickleInterval:     cfg.TrickleInterval,
 		DisableStallHandler: cfg.DisableStallHandler,
-		UsingV2Conn:         true,
+		UsingV2Conn:         cfg.V2Transport,
 	}
 }
 
@@ -2782,6 +2782,9 @@ func newServer(listenAddrs, agentBlacklist, agentWhitelist []string,
 	if cfg.Prune != 0 {
 		services &^= wire.SFNodeNetwork
 	}
+	if !cfg.V2Transport {
+		services &^= wire.SFNodeP2PV2
+	}
 
 	amgr := addrmgr.New(cfg.DataDir, btcdLookup)