Fix IPv6 addresses gathering

Fix isSupportedIPv6 function, when a global unicast address passed to,
the function returns false.

Resolves #176

README.md

@@ -52,6 +52,7 @@ Check out the **[contributing wiki](https://github.com/pion/webrtc/wiki/Contribu
 * [Ori Bernstein](https://eigenstate.org)
 * [Sam Lancia](https://github.com/nerd2)
 * [Lander Noterman](https://github.com/LanderN)
+* [BUPTCZQ](https://github.com/buptczq)
 * [Henry](https://github.com/cryptix)
 
 ### License

util.go

@@ -25,7 +25,7 @@ func (a *atomicError) Load() error {
 // https://tools.ietf.org/html/rfc8445#section-5.1.1.1
 func isSupportedIPv6(ip net.IP) bool {
 	if len(ip) != net.IPv6len ||
-		!isZeros(ip[0:12]) || // !(IPv4-compatible IPv6)
+		isZeros(ip[0:12]) || // !(IPv4-compatible IPv6)
 		ip[0] == 0xfe && ip[1]&0xc0 == 0xc0 || // !(IPv6 site-local unicast)
 		ip.IsLinkLocalUnicast() ||
 		ip.IsLinkLocalMulticast() {

util_test.go

@@ -0,0 +1,28 @@
+package ice
+
+import (
+	"net"
+	"testing"
+)
+
+func TestIsSupportedIPv6(t *testing.T) {
+	if isSupportedIPv6(net.IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1}) {
+		t.Errorf("isSupportedIPv6 return true with IPv4-compatible IPv6 address")
+	}
+
+	if isSupportedIPv6(net.ParseIP("fec0::2333")) {
+		t.Errorf("isSupportedIPv6 return true with IPv6 site-local unicast address")
+	}
+
+	if isSupportedIPv6(net.ParseIP("fe80::2333")) {
+		t.Errorf("isSupportedIPv6 return true with IPv6 link-local address")
+	}
+
+	if isSupportedIPv6(net.ParseIP("ff02::2333")) {
+		t.Errorf("isSupportedIPv6 return true with IPv6 link-local multicast address")
+	}
+
+	if !isSupportedIPv6(net.ParseIP("2001::1")) {
+		t.Errorf("isSupportedIPv6 return false with IPv6 global unicast address")
+	}
+}