From 387096b2a111331fa8e22cab7a35c01c43019aa5 Mon Sep 17 00:00:00 2001
From: WofWca <wofwca@protonmail.com>
Date: Mon, 18 Nov 2024 20:46:27 +0400
Subject: [PATCH 1/2] refactor: rewrite `IsLocal` with `ip.IsPrivate()`

The referenced MR has been implemented.
The extra checks have been added in 8467c01e9e88523fcdef22fed8efadbd07484966.

With this rewrite the checks are exactly the same as of Go 1.23.3.
---
 common/util/util.go | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/common/util/util.go b/common/util/util.go
index 55b2656..57170cf 100644
--- a/common/util/util.go
+++ b/common/util/util.go
@@ -56,20 +56,21 @@ func DeserializeSessionDescription(msg string) (*webrtc.SessionDescription, erro
 	}, nil
 }
 
-// Stolen from https://github.com/golang/go/pull/30278
 func IsLocal(ip net.IP) bool {
-	if ip4 := ip.To4(); ip4 != nil {
-		// Local IPv4 addresses are defined in https://tools.ietf.org/html/rfc1918
-		return ip4[0] == 10 ||
-			(ip4[0] == 172 && ip4[1]&0xf0 == 16) ||
-			(ip4[0] == 192 && ip4[1] == 168) ||
-			// Carrier-Grade NAT as per https://tools.ietf.org/htm/rfc6598
-			(ip4[0] == 100 && ip4[1]&0xc0 == 64) ||
-			// Dynamic Configuration as per https://tools.ietf.org/htm/rfc3927
-			(ip4[0] == 169 && ip4[1] == 254)
+	if ip.IsPrivate() {
+		return true
 	}
-	// Local IPv6 addresses are defined in https://tools.ietf.org/html/rfc4193
-	return len(ip) == net.IPv6len && ip[0]&0xfe == 0xfc
+	if ip4 := ip.To4(); ip4 != nil {
+		// Carrier-Grade NAT as per https://tools.ietf.org/htm/rfc6598
+		if ip4[0] == 100 && ip4[1]&0xc0 == 64 {
+			return true
+		}
+		// Dynamic Configuration as per https://tools.ietf.org/htm/rfc3927
+		if ip4[0] == 169 && ip4[1] == 254 {
+			return true
+		}
+	}
+	return false
 }
 
 // Removes local LAN address ICE candidates

From f65f1d850f6ae7a4115605f2892a2f69cdfb5bc5 Mon Sep 17 00:00:00 2001
From: WofWca <wofwca@protonmail.com>
Date: Thu, 21 Nov 2024 17:31:56 +0400
Subject: [PATCH 2/2] improvement: use IsLinkLocalUnicast in IsLocal

Looking at the code, this commit appears to change behavior,
because `IsLocal` will now return `true` for IPv6 link-local unicast
addresses.
---
 common/util/util.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/common/util/util.go b/common/util/util.go
index 57170cf..a180692 100644
--- a/common/util/util.go
+++ b/common/util/util.go
@@ -60,15 +60,15 @@ func IsLocal(ip net.IP) bool {
 	if ip.IsPrivate() {
 		return true
 	}
+	// Dynamic Configuration as per https://tools.ietf.org/htm/rfc3927
+	if ip.IsLinkLocalUnicast() {
+		return true
+	}
 	if ip4 := ip.To4(); ip4 != nil {
 		// Carrier-Grade NAT as per https://tools.ietf.org/htm/rfc6598
 		if ip4[0] == 100 && ip4[1]&0xc0 == 64 {
 			return true
 		}
-		// Dynamic Configuration as per https://tools.ietf.org/htm/rfc3927
-		if ip4[0] == 169 && ip4[1] == 254 {
-			return true
-		}
 	}
 	return false
 }