disco: add PortScanOffset config

sigcn · Jun 1, 2024 · 95f057a · 95f057a
1 parent e050b0e
commit 95f057a
Show file tree

Hide file tree

Showing 3 changed files with 10 additions and 1 deletion.
diff --git a/cmd/pgcli/vpn/vpn.go b/cmd/pgcli/vpn/vpn.go
@@ -52,6 +52,7 @@ func init() {
 	Cmd.Flags().StringSlice("allowed-ip", []string{}, "declare IPs that can be routed/NATed by this machine (i.e. 192.168.0.0/24)")
 	Cmd.Flags().StringSlice("peer", []string{}, "specify peers instead of auto-discovery (pg://<peerID>?alias1=<ipv4>&alias2=<ipv6>)")
 
+	Cmd.Flags().Int("disco-port-scan-offset", -500, "scan ports offset when disco")
 	Cmd.Flags().Int("disco-port-scan-count", 2000, "scan ports count when disco")
 	Cmd.Flags().Int("disco-challenges-retry", 5, "ping challenges retry count when disco")
 	Cmd.Flags().Duration("disco-challenges-initial-interval", 200*time.Millisecond, "ping challenges initial interval when disco")
@@ -74,6 +75,10 @@ func run(cmd *cobra.Command, args []string) (err error) {
 }
 
 func createConfig(cmd *cobra.Command) (cfg Config, err error) {
+	cfg.DiscoPortScanOffset, err = cmd.Flags().GetInt("disco-port-scan-offset")
+	if err != nil {
+		return
+	}
 	cfg.DiscoPortScanCount, err = cmd.Flags().GetInt("disco-port-scan-count")
 	if err != nil {
 		return
@@ -131,6 +136,7 @@ func createConfig(cmd *cobra.Command) (cfg Config, err error) {
 
 type Config struct {
 	iface.Config
+	DiscoPortScanOffset            int
 	DiscoPortScanCount             int
 	DiscoChallengesRetry           int
 	DiscoChallengesInitialInterval time.Duration
@@ -164,6 +170,7 @@ func (v *P2PVPN) Run(ctx context.Context) error {
 
 func (v *P2PVPN) listenPacketConn(ctx context.Context) (c net.PacketConn, err error) {
 	disco.SetModifyDiscoConfig(func(cfg *disco.DiscoConfig) {
+		cfg.PortScanOffset = v.Config.DiscoPortScanOffset
 		cfg.PortScanCount = v.Config.DiscoPortScanCount
 		cfg.ChallengesRetry = v.Config.DiscoChallengesRetry
 		cfg.ChallengesInitialInterval = v.Config.DiscoChallengesInitialInterval

diff --git a/disco/disco.go b/disco/disco.go
@@ -18,13 +18,15 @@ var (
 )
 
 var defaultDiscoConfig = DiscoConfig{
+	PortScanOffset:            -500,
 	PortScanCount:             2000,
 	ChallengesRetry:           5,
 	ChallengesInitialInterval: 200 * time.Millisecond,
 	ChallengesBackoffRate:     1.65,
 }
 
 type DiscoConfig struct {
+	PortScanOffset            int
 	PortScanCount             int
 	ChallengesRetry           int
 	ChallengesInitialInterval time.Duration

diff --git a/disco/udp.go b/disco/udp.go
@@ -171,7 +171,7 @@ func (c *UDPConn) RunDiscoMessageSendLoop(peerID peer.ID, addr *net.UDPAddr) {
 
 	if ctx, ok := c.FindPeer(peerID); (!ok || !ctx.Ready()) && addr.IP.To4() != nil && !addr.IP.IsPrivate() {
 		slog.Info("[UDP] PortScanning", "peer", peerID, "addr", addr)
-		for port := addr.Port + 1; port <= addr.Port+defaultDiscoConfig.PortScanCount; port++ {
+		for port := addr.Port + defaultDiscoConfig.PortScanOffset; port <= addr.Port+defaultDiscoConfig.PortScanCount; port++ {
 			select {
 			case <-c.closedSig:
 				return