add socks

pkg/connector/socks/v4/connector.go

@@ -0,0 +1,119 @@
+package v4
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/url"
+	"strconv"
+	"time"
+
+	"github.com/go-gost/gosocks4"
+	"github.com/go-gost/gost/pkg/connector"
+	"github.com/go-gost/gost/pkg/logger"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/go-gost/gost/pkg/registry"
+)
+
+func init() {
+	registry.RegiserConnector("socks4", NewConnector)
+	registry.RegiserConnector("socks4a", NewConnector)
+}
+
+type socks4Connector struct {
+	md     metadata
+	logger logger.Logger
+}
+
+func NewConnector(opts ...connector.Option) connector.Connector {
+	options := &connector.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &socks4Connector{
+		logger: options.Logger,
+	}
+}
+
+func (c *socks4Connector) Init(md md.Metadata) (err error) {
+	return c.parseMetadata(md)
+}
+
+func (c *socks4Connector) Connect(ctx context.Context, conn net.Conn, network, address string, opts ...connector.ConnectOption) (net.Conn, error) {
+	c.logger = c.logger.WithFields(map[string]interface{}{
+		"remote": conn.RemoteAddr().String(),
+		"local":  conn.LocalAddr().String(),
+		"target": address,
+	})
+	c.logger.Info("connect: ", address)
+
+	var addr *gosocks4.Addr
+
+	if c.md.disable4a {
+		taddr, err := net.ResolveTCPAddr("tcp4", address)
+		if err != nil {
+			c.logger.Error("resolve: ", err)
+			return nil, err
+		}
+		if len(taddr.IP) == 0 {
+			taddr.IP = net.IPv4zero
+		}
+		addr = &gosocks4.Addr{
+			Type: gosocks4.AddrIPv4,
+			Host: taddr.IP.String(),
+			Port: uint16(taddr.Port),
+		}
+	} else {
+		host, port, err := net.SplitHostPort(address)
+		if err != nil {
+			return nil, err
+		}
+		p, _ := strconv.Atoi(port)
+		addr = &gosocks4.Addr{
+			Type: gosocks4.AddrDomain,
+			Host: host,
+			Port: uint16(p),
+		}
+	}
+
+	if c.md.connectTimeout > 0 {
+		conn.SetDeadline(time.Now().Add(c.md.connectTimeout))
+	}
+	defer conn.SetDeadline(time.Time{})
+
+	req := gosocks4.NewRequest(gosocks4.CmdConnect, addr, nil)
+	if err := req.Write(conn); err != nil {
+		c.logger.Error(err)
+		return nil, err
+	}
+	if c.logger.IsLevelEnabled(logger.DebugLevel) {
+		c.logger.Debug(req)
+	}
+
+	reply, err := gosocks4.ReadReply(conn)
+	if err != nil {
+		c.logger.Error(err)
+		return nil, err
+	}
+
+	if c.logger.IsLevelEnabled(logger.DebugLevel) {
+		c.logger.Debug(reply)
+	}
+
+	if reply.Code != gosocks4.Granted {
+		return nil, fmt.Errorf("error: %d", reply.Code)
+	}
+
+	return conn, nil
+}
+
+func (c *socks4Connector) parseMetadata(md md.Metadata) (err error) {
+	if v := md.GetString(auth); v != "" {
+		c.md.User = url.User(v)
+	}
+	c.md.connectTimeout = md.GetDuration(connectTimeout)
+	c.md.disable4a = md.GetBool(disable4a)
+
+	return
+}

pkg/connector/socks/v4/metadata.go

@@ -0,0 +1,18 @@
+package v4
+
+import (
+	"net/url"
+	"time"
+)
+
+const (
+	connectTimeout = "timeout"
+	auth           = "auth"
+	disable4a      = "disable4a"
+)
+
+type metadata struct {
+	connectTimeout time.Duration
+	User           *url.Userinfo
+	disable4a      bool
+}