p2p: add disable reuseport option (#4539)

reuseport https://lwn.net/Articles/542629/ .
we know that some nodes can't reach bootnodes, behavior matches what is described in the comment below https://github.com/ipfs/kubo/issues/6548#issuecomment-517372924https://github.com/ipfs/kubo/issues/6548#issuecomment-517372924

> Meaning that you've exceeded the 10s timeout for the connection. Your ISP may be blocking or rate-limiting connections from low-numbered ports.

cmd/root.go

@@ -80,8 +80,9 @@ func AddCommands(cmd *cobra.Command) {
 
 	cmd.PersistentFlags().IntVar(&cfg.DatabaseConnections, "db-connections",
 		cfg.DatabaseConnections, "configure number of active connections to enable parallel read requests")
-	cmd.PersistentFlags().BoolVar(&cfg.P2P.Flood, "db-latency-metering",
+	cmd.PersistentFlags().BoolVar(&cfg.DatabaseLatencyMetering, "db-latency-metering",
 		cfg.DatabaseLatencyMetering, "if enabled collect latency histogram for every database query")
+
 	/** ======================== P2P Flags ========================== **/
 
 	cmd.PersistentFlags().StringVar(&cfg.P2P.Listen, "listen",
@@ -90,6 +91,11 @@ func AddCommands(cmd *cobra.Command) {
 		cfg.P2P.Flood, "flood created messages to all peers")
 	cmd.PersistentFlags().BoolVar(&cfg.P2P.DisableNatPort, "disable-natport",
 		cfg.P2P.DisableNatPort, "disable nat port-mapping (if enabled upnp protocol is used to negotiate external port with router)")
+	cmd.PersistentFlags().BoolVar(&cfg.P2P.DisableReusePort,
+		"disable-reuseport",
+		cfg.P2P.DisableReusePort,
+		"disables SO_REUSEPORT for tcp sockets. Try disabling this if your node can't reach bootnodes in the network",
+	)
 	cmd.PersistentFlags().IntVar(&cfg.P2P.LowPeers, "low-peers",
 		cfg.P2P.LowPeers, "low watermark for the number of connections")
 	cmd.PersistentFlags().IntVar(&cfg.P2P.HighPeers, "high-peers",

p2p/host.go

@@ -8,7 +8,9 @@ import (
 	lp2plog "github.com/ipfs/go-log/v2"
 	"github.com/libp2p/go-libp2p"
 	"github.com/libp2p/go-libp2p/core/crypto"
+	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/libp2p/go-libp2p/core/protocol"
+	"github.com/libp2p/go-libp2p/core/transport"
 	"github.com/libp2p/go-libp2p/p2p/host/peerstore/pstoremem"
 	"github.com/libp2p/go-libp2p/p2p/muxer/yamux"
 	"github.com/libp2p/go-libp2p/p2p/net/connmgr"
@@ -40,6 +42,8 @@ type Config struct {
 	GracePeersShutdown time.Duration
 	MaxMessageSize     int
 
+	// see https://lwn.net/Articles/542629/ for reuseport explanation
+	DisableReusePort bool     `mapstructure:"disable-reuseport"`
 	DisableNatPort   bool     `mapstructure:"disable-natport"`
 	Flood            bool     `mapstructure:"flood"`
 	Listen           string   `mapstructure:"listen"`
@@ -74,7 +78,13 @@ func New(_ context.Context, logger log.Log, cfg Config, prologue []byte, opts ..
 		libp2p.UserAgent("go-spacemesh"),
 		libp2p.DisableRelay(),
 
-		libp2p.Transport(tcp.NewTCPTransport),
+		libp2p.Transport(func(upgrader transport.Upgrader, rcmgr network.ResourceManager) (transport.Transport, error) {
+			opts := []tcp.Option{}
+			if cfg.DisableReusePort {
+				opts = append(opts, tcp.DisableReuseport())
+			}
+			return tcp.NewTCPTransport(upgrader, rcmgr, opts...)
+		}),
 		libp2p.Security(noise.ID, func(id protocol.ID, privkey crypto.PrivKey, muxers []tptu.StreamMuxer) (*noise.SessionTransport, error) {
 			tp, err := noise.New(id, privkey, muxers)
 			if err != nil {