p2p: add --use-proxy flag for SOCKS5 proxy support

Add support for routing P2P connections through a SOCKS5 proxy specified
via ALL_PROXY or all_proxy environment variables. This enables nodes to
connect to peers through proxy servers when needed.

Key changes:
- Add --use-proxy CLI flag to enable proxy detection
- Implement proxy dialing with context cancellation support
- Add debug logging to track proxy usage
- Prevent goroutine leaks on context cancellation

The implementation uses golang.org/x/net/proxy.FromEnvironment() which
detects SOCKS5 proxies from ALL_PROXY/all_proxy environment variables.

Signed-off-by: Cloorc <wittcnezh@foxmail.com>
Signed-off-by: cloorc <wittcnezh@foxmail.com>

Author: cloorc

cmd/geth/main.go

@@ -144,6 +144,7 @@ var (
 		utils.NoDiscoverFlag,
 		utils.DiscoveryV4Flag,
 		utils.DiscoveryV5Flag,
+		utils.UseProxyFlag,
 		utils.LegacyDiscoveryV5Flag, // deprecated
 		utils.NetrestrictFlag,
 		utils.NodeKeyFileFlag,

cmd/utils/flags.go

@@ -941,6 +941,11 @@ var (
 		Usage:    "Enables the experimental RLPx V5 (Topic Discovery) mechanism",
 		Category: flags.NetworkingCategory,
 	}
+	UseProxyFlag = &cli.BoolFlag{
+		Name:     "use-proxy",
+		Usage:    "Use SOCKS5 proxy from ALL_PROXY or all_proxy environment variable for peer connections",
+		Category: flags.NetworkingCategory,
+	}
 	NetrestrictFlag = &cli.StringFlag{
 		Name:     "netrestrict",
 		Usage:    "Restricts network communication to the given IP networks (CIDR masks)",
@@ -1552,6 +1557,7 @@ func SetP2PConfig(ctx *cli.Context, cfg *p2p.Config) {
 	CheckExclusive(ctx, DiscoveryV5Flag, NoDiscoverFlag)
 	cfg.DiscoveryV4 = ctx.Bool(DiscoveryV4Flag.Name)
 	cfg.DiscoveryV5 = ctx.Bool(DiscoveryV5Flag.Name)
+	cfg.UseProxy = ctx.Bool(UseProxyFlag.Name)
 
 	if netrestrict := ctx.String(NetrestrictFlag.Name); netrestrict != "" {
 		list, err := netutil.ParseNetlist(netrestrict)

go.mod

@@ -67,7 +67,7 @@ require (
 	github.com/spf13/cobra v1.5.0
 	github.com/status-im/keycard-go v0.2.0
 	github.com/stretchr/testify v1.8.4
-	github.com/supranational/blst v0.3.11
+	github.com/supranational/blst v0.3.14
 	github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7
 	github.com/tidwall/gjson v1.6.0
 	github.com/tyler-smith/go-bip39 v1.1.0
@@ -76,6 +76,7 @@ require (
 	go.uber.org/automaxprocs v1.5.2
 	golang.org/x/crypto v0.17.0
 	golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa
+	golang.org/x/net v0.18.0
 	golang.org/x/sync v0.5.0
 	golang.org/x/sys v0.16.0
 	golang.org/x/text v0.14.0
@@ -177,7 +178,6 @@ require (
 	github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
 	golang.org/x/image v0.11.0 // indirect
 	golang.org/x/mod v0.14.0 // indirect
-	golang.org/x/net v0.18.0 // indirect
 	golang.org/x/xerrors v0.0.0-20220517211312-f3a8303e98df // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect

go.sum

@@ -662,8 +662,8 @@ github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-github.com/supranational/blst v0.3.11 h1:LyU6FolezeWAhvQk0k6O/d49jqgO52MSDDfYgbeoEm4=
-github.com/supranational/blst v0.3.11/go.mod h1:jZJtfjgudtNl4en1tzwPIV3KjUnQUvG3/j+w+fVonLw=
+github.com/supranational/blst v0.3.14 h1:xNMoHRJOTwMn63ip6qoWJ2Ymgvj7E2b9jY2FAwY+qRo=
+github.com/supranational/blst v0.3.14/go.mod h1:jZJtfjgudtNl4en1tzwPIV3KjUnQUvG3/j+w+fVonLw=
 github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 h1:epCh84lMvA70Z7CTTCmYQn2CKbY8j86K7/FAIr141uY=
 github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7/go.mod h1:q4W45IWZaF22tdD+VEXcAWRA037jwmWEB5VWYORlTpc=
 github.com/tidwall/gjson v1.6.0 h1:9VEQWz6LLMUsUl6PueE49ir4Ka6CzLymOAZDxpFsTDc=

p2p/dial.go

@@ -32,6 +32,7 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
+	"golang.org/x/net/proxy"
 )
 
 const (
@@ -61,11 +62,28 @@ type nodeResolver interface {
 
 // tcpDialer implements NodeDialer using real TCP connections.
 type tcpDialer struct {
-	d *net.Dialer
+	d        *net.Dialer
+	useProxy bool
 }
 
+// dialerWithContext is an interface implemented by proxy dialers that support context-aware dialing.
+// see proxy/direct#direct, proxy.SOCKS5() and internal/socks#Dialer.
+type dialerWithContext interface {
+	DialContext(ctx context.Context, network, address string) (net.Conn, error)
+}
+
+var proxyDialer = proxy.FromEnvironment()
+
 func (t tcpDialer) Dial(ctx context.Context, dest *enode.Node) (net.Conn, error) {
 	addr, _ := dest.TCPEndpoint()
+	if t.useProxy {
+		log.Debug("Dialing peer via proxy", "direct", proxyDialer == proxy.Direct, "addr", addr.String())
+		if v, ok := proxyDialer.(dialerWithContext); ok {
+			return v.DialContext(ctx, "tcp", addr.String())
+		} else {
+			log.Warn("Proxy dialer does not support context, falling back to direct", "addr", addr.String())
+		}
+	}
 	return t.d.DialContext(ctx, "tcp", addr.String())
 }
 

p2p/server.go

@@ -166,6 +166,9 @@ type Config struct {
 	// Logger is a custom logger to use with the p2p.Server.
 	Logger log.Logger `toml:",omitempty"`
 
+	// If UseProxy is set to true, the server will use SOCKS5 proxy from ALL_PROXY or all_proxy environment variable for dialing peers.
+	UseProxy bool `toml:",omitempty"`
+
 	clock mclock.Clock
 }
 
@@ -617,7 +620,7 @@ func (srv *Server) setupDialScheduler() {
 		config.resolver = srv.discv4
 	}
 	if config.dialer == nil {
-		config.dialer = tcpDialer{&net.Dialer{Timeout: defaultDialTimeout}}
+		config.dialer = tcpDialer{&net.Dialer{Timeout: defaultDialTimeout}, srv.UseProxy}
 	}
 	srv.dialsched = newDialScheduler(config, srv.discmix, srv.SetupConn)
 	for _, n := range srv.StaticNodes {