Add FindDialer addon

go.mod

@@ -11,6 +11,7 @@ require (
 )
 
 require (
-	golang.org/x/sys v0.0.0-20220624220833-87e55d714810 // indirect
+	golang.org/x/net v0.7.0 // indirect
+	golang.org/x/sys v0.5.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 )

go.sum

@@ -19,8 +19,12 @@ github.com/sirupsen/logrus v1.8.1 h1:dJKuHgqk1NNQlqoA6BTlM1Wf9DOH3NBjQyu0h9+AZZE
 github.com/sirupsen/logrus v1.8.1/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/net v0.7.0 h1:rJrUqqhjsgNp7KqAIc25s9pZnjU7TUcSY7HcVZjdn1g=
+golang.org/x/net v0.7.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20220624220833-87e55d714810 h1:rHZQSjJdAI4Xf5Qzeh2bBc5YJIkPFVM6oDtMFYmgws0=
 golang.org/x/sys v0.0.0-20220624220833-87e55d714810/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0 h1:MUK/U/4lj1t1oPg0HfuXDN/Z1wv31ZJ/YcPiGccS4DU=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

proxy/addon.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	log "github.com/sirupsen/logrus"
+	"golang.org/x/net/proxy"
 )
 
 type Addon interface {
@@ -14,6 +15,9 @@ type Addon interface {
 	// A client connection has been closed (either by us or the client).
 	ClientDisconnected(*ClientConn)
 
+	// A new connection will be established, at most one add on can provide a dialer.
+	FindDialer(connCtx *ConnContext, addr string) proxy.ContextDialer
+
 	// Mitmproxy has connected to a server.
 	ServerConnected(*ConnContext)
 
@@ -47,6 +51,7 @@ type BaseAddon struct{}
 
 func (addon *BaseAddon) ClientConnected(*ClientConn)     {}
 func (addon *BaseAddon) ClientDisconnected(*ClientConn)  {}
+func (addon *BaseAddon) FindDialer(connContext *ConnContext, addr string) proxy.ContextDialer { return nil }
 func (addon *BaseAddon) ServerConnected(*ConnContext)    {}
 func (addon *BaseAddon) ServerDisconnected(*ConnContext) {}
 
@@ -76,6 +81,11 @@ func (addon *LogAddon) ClientDisconnected(client *ClientConn) {
 	log.Infof("%v client disconnect\n", client.Conn.RemoteAddr())
 }
 
+func (addon *LogAddon) FindDialer(connCtx *ConnContext, addr string) proxy.ContextDialer {
+	log.Infof("asked for dialer for %v\n", connCtx.ServerConn)
+	return nil
+}
+
 func (addon *LogAddon) ServerConnected(connCtx *ConnContext) {
 	log.Infof("%v server connect %v (%v->%v)\n", connCtx.ClientConn.Conn.RemoteAddr(), connCtx.ServerConn.Address, connCtx.ServerConn.Conn.LocalAddr(), connCtx.ServerConn.Conn.RemoteAddr())
 }

proxy/connection.go

@@ -15,6 +15,7 @@ import (
 
 	uuid "github.com/satori/go.uuid"
 	log "github.com/sirupsen/logrus"
+	"golang.org/x/net/proxy"
 )
 
 // client connection
@@ -100,8 +101,19 @@ func (connCtx *ConnContext) Id() uuid.UUID {
 	return connCtx.ClientConn.Id
 }
 
+func (connCtx *ConnContext) dialer(network string, addr string) proxy.ContextDialer {
+	for _, addon := range connCtx.proxy.Addons {
+		dialer := addon.FindDialer(connCtx, addr)
+		if dialer != nil {
+			return dialer
+		}
+	}
+	return &net.Dialer{}
+}
+
 func (connCtx *ConnContext) initHttpServerConn() {
 	if connCtx.ServerConn != nil {
+		log.Infof("There was a server conn %v", connCtx.ServerConn)
 		return
 	}
 	if connCtx.ClientConn.Tls {
@@ -120,7 +132,8 @@ func (connCtx *ConnContext) initHttpServerConn() {
 		Transport: &http.Transport{
 			Proxy: useProxy,
 			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
-				c, err := (&net.Dialer{}).DialContext(ctx, network, addr)
+				dialer := connCtx.dialer(network, addr)
+				c, err := dialer.DialContext(ctx, network, addr)
 				if err != nil {
 					return nil, err
 				}
@@ -159,7 +172,10 @@ func (connCtx *ConnContext) initServerTcpConn(req *http.Request) error {
 	connCtx.ServerConn = ServerConn
 	ServerConn.Address = connCtx.pipeConn.host
 
-	plainConn, err := getConnFrom(req.Host, connCtx.proxy.Opts.Upstream)
+	dialer := connCtx.dialer("tcp", req.Host)
+
+	plainConn, err := dialer.DialContext(context.Background(), "tcp", req.Host)
+
 	if err != nil {
 		return err
 	}