[tor-commits] [snowflake/main] Refactor webRTCConn to its own file

[meskio at torproject.org]

commit ced539f234af4fbf460787b5f50eb78098406774
Author: meskio <meskio at torproject.org>
Date:   Fri Jun 25 18:37:31 2021 +0200

    Refactor webRTCConn to its own file
---
 proxy/snowflake.go  | 109 ----------------------------------------------
 proxy/webrtcconn.go | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 121 insertions(+), 109 deletions(-)

diff --git a/proxy/snowflake.go b/proxy/snowflake.go
index f7eacf8..12d97d3 100644
--- a/proxy/snowflake.go
+++ b/proxy/snowflake.go
@@ -13,7 +13,6 @@ import (
 	"net/http"
 	"net/url"
 	"os"
-	"regexp"
 	"strings"
 	"sync"
 	"time"
@@ -23,8 +22,6 @@ import (
 	"git.torproject.org/pluggable-transports/snowflake.git/common/util"
 	"git.torproject.org/pluggable-transports/snowflake.git/common/websocketconn"
 	"github.com/gorilla/websocket"
-	"github.com/pion/ice/v2"
-	"github.com/pion/sdp/v3"
 	"github.com/pion/webrtc/v3"
 )
 
@@ -60,117 +57,11 @@ var (
 	client http.Client
 )
 
-var remoteIPPatterns = []*regexp.Regexp{
-	/* IPv4 */
-	regexp.MustCompile(`(?m)^c=IN IP4 ([\d.]+)(?:(?:\/\d+)?\/\d+)?(:? |\r?\n)`),
-	/* IPv6 */
-	regexp.MustCompile(`(?m)^c=IN IP6 ([0-9A-Fa-f:.]+)(?:\/\d+)?(:? |\r?\n)`),
-}
-
 // Checks whether an IP address is a remote address for the client
 func isRemoteAddress(ip net.IP) bool {
 	return !(util.IsLocal(ip) || ip.IsUnspecified() || ip.IsLoopback())
 }
 
-func remoteIPFromSDP(str string) net.IP {
-	// Look for remote IP in "a=candidate" attribute fields
-	// https://tools.ietf.org/html/rfc5245#section-15.1
-	var desc sdp.SessionDescription
-	err := desc.Unmarshal([]byte(str))
-	if err != nil {
-		log.Println("Error parsing SDP: ", err.Error())
-		return nil
-	}
-	for _, m := range desc.MediaDescriptions {
-		for _, a := range m.Attributes {
-			if a.IsICECandidate() {
-				c, err := ice.UnmarshalCandidate(a.Value)
-				if err == nil {
-					ip := net.ParseIP(c.Address())
-					if ip != nil && isRemoteAddress(ip) {
-						return ip
-					}
-				}
-			}
-		}
-	}
-	// Finally look for remote IP in "c=" Connection Data field
-	// https://tools.ietf.org/html/rfc4566#section-5.7
-	for _, pattern := range remoteIPPatterns {
-		m := pattern.FindStringSubmatch(str)
-		if m != nil {
-			// Ignore parsing errors, ParseIP returns nil.
-			ip := net.ParseIP(m[1])
-			if ip != nil && isRemoteAddress(ip) {
-				return ip
-			}
-
-		}
-	}
-
-	return nil
-}
-
-type webRTCConn struct {
-	dc *webrtc.DataChannel
-	pc *webrtc.PeerConnection
-	pr *io.PipeReader
-
-	lock sync.Mutex // Synchronization for DataChannel destruction
-	once sync.Once  // Synchronization for PeerConnection destruction
-
-	bytesLogger BytesLogger
-}
-
-func (c *webRTCConn) Read(b []byte) (int, error) {
-	return c.pr.Read(b)
-}
-
-func (c *webRTCConn) Write(b []byte) (int, error) {
-	c.bytesLogger.AddInbound(len(b))
-	c.lock.Lock()
-	defer c.lock.Unlock()
-	if c.dc != nil {
-		c.dc.Send(b)
-	}
-	return len(b), nil
-}
-
-func (c *webRTCConn) Close() (err error) {
-	c.once.Do(func() {
-		err = c.pc.Close()
-	})
-	return
-}
-
-func (c *webRTCConn) LocalAddr() net.Addr {
-	return nil
-}
-
-func (c *webRTCConn) RemoteAddr() net.Addr {
-	//Parse Remote SDP offer and extract client IP
-	clientIP := remoteIPFromSDP(c.pc.RemoteDescription().SDP)
-	if clientIP == nil {
-		return nil
-	}
-	return &net.IPAddr{IP: clientIP, Zone: ""}
-}
-
-func (c *webRTCConn) SetDeadline(t time.Time) error {
-	// nolint: golint
-	return fmt.Errorf("SetDeadline not implemented")
-}
-
-func (c *webRTCConn) SetReadDeadline(t time.Time) error {
-	// nolint: golint
-	return fmt.Errorf("SetReadDeadline not implemented")
-}
-
-func (c *webRTCConn) SetWriteDeadline(t time.Time) error {
-	// nolint: golint
-	return fmt.Errorf("SetWriteDeadline not implemented")
-}
-
 func genSessionID() string {
 	buf := make([]byte, sessionIDLength)
 	_, err := rand.Read(buf)
diff --git a/proxy/webrtcconn.go b/proxy/webrtcconn.go
new file mode 100644
index 0000000..5d95919
--- /dev/null
+++ b/proxy/webrtcconn.go
@@ -0,0 +1,121 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"regexp"
+	"sync"
+	"time"
+
+	"github.com/pion/ice/v2"
+	"github.com/pion/sdp/v3"
+	"github.com/pion/webrtc/v3"
+)
+
+var remoteIPPatterns = []*regexp.Regexp{
+	/* IPv4 */
+	regexp.MustCompile(`(?m)^c=IN IP4 ([\d.]+)(?:(?:\/\d+)?\/\d+)?(:? |\r?\n)`),
+	/* IPv6 */
+	regexp.MustCompile(`(?m)^c=IN IP6 ([0-9A-Fa-f:.]+)(?:\/\d+)?(:? |\r?\n)`),
+}
+
+type webRTCConn struct {
+	dc *webrtc.DataChannel
+	pc *webrtc.PeerConnection
+	pr *io.PipeReader
+
+	lock sync.Mutex // Synchronization for DataChannel destruction
+	once sync.Once  // Synchronization for PeerConnection destruction
+
+	bytesLogger BytesLogger
+}
+
+func (c *webRTCConn) Read(b []byte) (int, error) {
+	return c.pr.Read(b)
+}
+
+func (c *webRTCConn) Write(b []byte) (int, error) {
+	c.bytesLogger.AddInbound(len(b))
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if c.dc != nil {
+		c.dc.Send(b)
+	}
+	return len(b), nil
+}
+
+func (c *webRTCConn) Close() (err error) {
+	c.once.Do(func() {
+		err = c.pc.Close()
+	})
+	return
+}
+
+func (c *webRTCConn) LocalAddr() net.Addr {
+	return nil
+}
+
+func (c *webRTCConn) RemoteAddr() net.Addr {
+	//Parse Remote SDP offer and extract client IP
+	clientIP := remoteIPFromSDP(c.pc.RemoteDescription().SDP)
+	if clientIP == nil {
+		return nil
+	}
+	return &net.IPAddr{IP: clientIP, Zone: ""}
+}
+
+func (c *webRTCConn) SetDeadline(t time.Time) error {
+	// nolint: golint
+	return fmt.Errorf("SetDeadline not implemented")
+}
+
+func (c *webRTCConn) SetReadDeadline(t time.Time) error {
+	// nolint: golint
+	return fmt.Errorf("SetReadDeadline not implemented")
+}
+
+func (c *webRTCConn) SetWriteDeadline(t time.Time) error {
+	// nolint: golint
+	return fmt.Errorf("SetWriteDeadline not implemented")
+}
+
+func remoteIPFromSDP(str string) net.IP {
+	// Look for remote IP in "a=candidate" attribute fields
+	// https://tools.ietf.org/html/rfc5245#section-15.1
+	var desc sdp.SessionDescription
+	err := desc.Unmarshal([]byte(str))
+	if err != nil {
+		log.Println("Error parsing SDP: ", err.Error())
+		return nil
+	}
+	for _, m := range desc.MediaDescriptions {
+		for _, a := range m.Attributes {
+			if a.IsICECandidate() {
+				c, err := ice.UnmarshalCandidate(a.Value)
+				if err == nil {
+					ip := net.ParseIP(c.Address())
+					if ip != nil && isRemoteAddress(ip) {
+						return ip
+					}
+				}
+			}
+		}
+	}
+	// Finally look for remote IP in "c=" Connection Data field
+	// https://tools.ietf.org/html/rfc4566#section-5.7
+	for _, pattern := range remoteIPPatterns {
+		m := pattern.FindStringSubmatch(str)
+		if m != nil {
+			// Ignore parsing errors, ParseIP returns nil.
+			ip := net.ParseIP(m[1])
+			if ip != nil && isRemoteAddress(ip) {
+				return ip
+			}
+
+		}
+	}
+
+	return nil
+}