From 7b33f85353a2080145c9fdbbb8cb83bbf28e65d2 Mon Sep 17 00:00:00 2001
From: Aleksandr Razumov <ar@gortc.io>
Date: Tue, 21 May 2019 13:14:54 +0300
Subject: [PATCH] Merge GetMappedAddressUDP

The GetMappedAddressUDP function was moved from stun v0.2.2, adapted to
gortc API and slightly simplified.
---
 gather.go | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 go.mod    |  1 -
 go.sum    |  4 ----
 3 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/gather.go b/gather.go
index 92a5f46..8db9078 100644
--- a/gather.go
+++ b/gather.go
@@ -5,8 +5,7 @@ import (
 	"net"
 	"time"
 
-	// TODO(ar): Merge
-	"github.com/pion/stun"
+	"github.com/gortc/stun"
 )
 
 func localInterfaces(networkTypes []NetworkType) (ips []net.IP) {
@@ -138,7 +137,7 @@ func gatherCandidatesReflective(a *Agent, urls []*URL, networkTypes []NetworkTyp
 						continue
 					}
 
-					xoraddr, err := stun.GetMappedAddressUDP(conn, serverAddr, time.Second*5)
+					xoraddr, err := getXORMappedAddr(conn, serverAddr, time.Second*5)
 					if err != nil {
 						a.log.Warnf("could not get server reflexive address %s %s: %v\n", network, url, err)
 						continue
@@ -170,3 +169,55 @@ func gatherCandidatesReflective(a *Agent, urls []*URL, networkTypes []NetworkTyp
 		}
 	}
 }
+
+// getXORMappedAddr initiates a stun requests to serverAddr using conn, reads the response and returns
+// the XORMappedAddress returned by the stun server.
+//
+// Adapted from stun v0.2.
+func getXORMappedAddr(conn *net.UDPConn, serverAddr net.Addr, deadline time.Duration) (*stun.XORMappedAddress, error) {
+	if deadline > 0 {
+		if err := conn.SetReadDeadline(time.Now().Add(deadline)); err != nil {
+			return nil, err
+		}
+	}
+	defer func() {
+		if deadline > 0 {
+			_ = conn.SetReadDeadline(time.Time{})
+		}
+	}()
+	resp, err := stunRequest(
+		conn.Read,
+		func(b []byte) (int, error) {
+			return conn.WriteTo(b, serverAddr)
+		},
+	)
+	if err != nil {
+		return nil, err
+	}
+	var addr stun.XORMappedAddress
+	if err = addr.GetFrom(resp); err != nil {
+		return nil, fmt.Errorf("failed to get XOR-MAPPED-ADDRESS response: %v", err)
+	}
+	return &addr, nil
+}
+
+func stunRequest(read func([]byte) (int, error), write func([]byte) (int, error)) (*stun.Message, error) {
+	req, err := stun.Build(stun.BindingRequest, stun.TransactionID)
+	if err != nil {
+		return nil, err
+	}
+	if _, err = write(req.Raw); err != nil {
+		return nil, err
+	}
+	const maxMessageSize = 1280
+	bs := make([]byte, maxMessageSize)
+	n, err := read(bs)
+	if err != nil {
+		return nil, err
+	}
+	res := &stun.Message{Raw: bs[:n]}
+	if err := res.Decode(); err != nil {
+		return nil, err
+	}
+	return res, nil
+}
diff --git a/go.mod b/go.mod
index 885180f..6829160 100644
--- a/go.mod
+++ b/go.mod
@@ -5,7 +5,6 @@ go 1.12
 require (
 	github.com/gortc/stun v1.19.0
 	github.com/pion/logging v0.2.1
-	github.com/pion/stun v0.2.2
 	github.com/pion/transport v0.7.0
 	github.com/stretchr/testify v1.3.0
 )
diff --git a/go.sum b/go.sum
index 804a8fd..82803d5 100644
--- a/go.sum
+++ b/go.sum
@@ -4,12 +4,8 @@ github.com/gortc/stun v1.19.0 h1:6qy7zGGk0tdMOdEzK7hLeAVZEHllJC8+OOBpPAyjY1c=
 github.com/gortc/stun v1.19.0/go.mod h1:dZ0O/fYCkg9Z0Pvl6WDpNhRFTAU0X1CPOsJiZqn6EHo=
 github.com/pion/logging v0.2.1 h1:LwASkBKZ+2ysGJ+jLv1E/9H1ge0k1nTfi1X+5zirkDk=
 github.com/pion/logging v0.2.1/go.mod h1:k0/tDVsRCX2Mb2ZEmTqNa7CWsQPc+YYCB7Q+5pahoms=
-github.com/pion/stun v0.2.2 h1:0IJCwJFOdEmHzz4oxl9SBGLlJbnNbF+0h6XSOmuE034=
-github.com/pion/stun v0.2.2/go.mod h1:TChCNKgwnFiFG/c9K+zqEdd6pO6tlODb9yN1W/zVfsE=
 github.com/pion/transport v0.7.0 h1:EsXN8TglHMlKZMo4ZGqwK6QgXBu0WYg7wfGMWIXsS+w=
 github.com/pion/transport v0.7.0/go.mod h1:iWZ07doqOosSLMhZ+FXUTq+TamDoXSllxpbGcfkCmbE=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
-github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=