feat: sniffer support

sniffer:
  enable: true
  force: false # Overwrite domain
  sniffing:
    - tls

component/sniffer/dispatcher.go

@@ -0,0 +1,104 @@
+package sniffer
+
+import (
+	"errors"
+	"net"
+
+	CN "github.com/Dreamacro/clash/common/net"
+	"github.com/Dreamacro/clash/component/resolver"
+	C "github.com/Dreamacro/clash/constant"
+	"github.com/Dreamacro/clash/log"
+)
+
+var (
+	ErrorUnsupportedSniffer = errors.New("unsupported sniffer")
+)
+
+var Dispatcher SnifferDispatcher
+
+type SnifferDispatcher struct {
+	enable   bool
+	force    bool
+	sniffers []C.Sniffer
+}
+
+func (sd *SnifferDispatcher) Tcp(conn net.Conn, metadata *C.Metadata) {
+	bufConn, ok := conn.(*CN.BufferedConn)
+	if !ok {
+		return
+	}
+
+	if sd.force {
+		sd.cover(bufConn, metadata)
+	} else {
+		if metadata.Host != "" {
+			return
+		}
+
+		sd.cover(bufConn, metadata)
+	}
+}
+
+func (sd *SnifferDispatcher) Enable() bool {
+	return sd.enable
+}
+
+func (sd *SnifferDispatcher) cover(conn *CN.BufferedConn, metadata *C.Metadata) {
+	for _, sniffer := range sd.sniffers {
+		if sniffer.SupportNetwork() == C.TCP {
+			conn.Peek(1)
+			len := conn.Buffered()
+			bytes, err := conn.Peek(len)
+			if err != nil {
+				log.Warnln("the data lenght not enough")
+				continue
+			}
+
+			host, err := sniffer.SniffTCP(bytes)
+			if err != nil {
+				log.Warnln("Sniff data failed on Sniffer[%s]", sniffer.Protocol())
+				continue
+			}
+
+			metadata.Host = host
+			metadata.DstIP = nil
+			metadata.AddrType = C.AtypDomainName
+			if resolver.FakeIPEnabled() {
+				metadata.DNSMode = C.DNSFakeIP
+			} else {
+				metadata.DNSMode = C.DNSMapping
+			}
+
+			resolver.InsertHostByIP(metadata.DstIP, host)
+			break
+		}
+	}
+}
+
+func NewSnifferDispatcher(needSniffer []C.SnifferType, force bool) (SnifferDispatcher, error) {
+	dispatcher := SnifferDispatcher{
+		enable: true,
+		force:  force,
+	}
+
+	for _, snifferName := range needSniffer {
+		sniffer, err := NewSniffer(snifferName)
+		if err != nil {
+			log.Errorln("Sniffer name[%s] is error", snifferName)
+			return SnifferDispatcher{enable: false}, err
+		}
+
+		dispatcher.sniffers = append(dispatcher.sniffers, sniffer)
+	}
+
+	return dispatcher, nil
+}
+
+func NewSniffer(name C.SnifferType) (C.Sniffer, error) {
+	switch name {
+	case C.TLS:
+		return &TLSSniffer{}, nil
+	default:
+		return nil, ErrorUnsupportedSniffer
+	}
+}