From c2c438b98da1b8b6840091f8f1156c23e867c077 Mon Sep 17 00:00:00 2001
From: Linda Lapinlampi <linda@lindalap.fi>
Date: Wed, 1 Jun 2022 20:52:00 +0000
Subject: [PATCH] ip2c: Reduce the IPv4 local loopback network from /8 to /16

Drafts have been submitted to IETF standards track reduce the size of IPv4
local loopback network ("localnet") size from /8 to /16, freeing up over
16 million IPv4-addresses as globally routable Unicast addresses on the
Internet (or other uses). This is part of a so-called "IPv4 Unicast
Extensions Project", started by Seth Schoen.

Doomseeker's IP2C code treated 127.0.0.0/8 specially: Servers from those
addresses would get assigned a special "Localhost" flag, instead of
country data returned from IP2C lookups. Now we only return "Localhost"
flags servers for in the 127.0.0.0/16 network.

Fixes: #4010
See: https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-127/
---
 src/core/ip2c/ip2c.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/ip2c/ip2c.h b/src/core/ip2c/ip2c.h
index e5403867..11927578 100644
--- a/src/core/ip2c/ip2c.h
+++ b/src/core/ip2c/ip2c.h
@@ -177,7 +177,7 @@ private:
 	inline bool isLocalhostAddress(unsigned ipv4Address)
 	{
 		const static unsigned LOCALHOST_BEGIN = QHostAddress("127.0.0.0").toIPv4Address();
-		const static unsigned LOCALHOST_END = QHostAddress("127.255.255.255").toIPv4Address();
+		const static unsigned LOCALHOST_END = QHostAddress("127.0.255.255").toIPv4Address();
 
 		return ipv4Address >= LOCALHOST_BEGIN && ipv4Address <= LOCALHOST_END;
 	}
-- 
2.36.1

From c184a97e5488211de34cafabfdcbf1aecbb3b70f Mon Sep 17 00:00:00 2001
From: Linda Lapinlampi <linda@lindalap.fi>
Date: Wed, 1 Jun 2022 21:10:19 +0000
Subject: [PATCH 2/2] CHANGELOG: Add #4010 (IPv4 Unicast Extensions Project)

---
 CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 38fee617..79714005 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,8 @@ method favored servers that were in the lower IP ranges.
 calculate the ping to the game server rather than using the port's
 feature where the timestamp is sent back in the challenge reply
 packet. (#3992)
+- Reduce the size of the IPv4 local loopback network ("localnet") from `/8` to
+`/16`, adopting the IPv4 Unicast Extensions Project. (#4010)
 
 ### Fixed
 - Zandronum, Q-Zandronum: servers that emitted empty PWAD names in their
-- 
2.36.1

From 9a628081d5770934ff43052f55addffe901c4f45 Mon Sep 17 00:00:00 2001
From: Linda Lapinlampi <linda@lindalap.fi>
Date: Wed, 1 Jun 2022 20:52:00 +0000
Subject: [PATCH v2 1/2] ip2c: Reduce the IPv4 local loopback network from /8
 to /16
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Drafts have been submitted to IETF standards track reduce the size of IPv4
local loopback network ("localnet") size from /8 to /16, freeing up over
16 million IPv4-addresses as globally routable Unicast addresses on the
Internet (or other uses). This is part of a so-called "IPv4 Unicast
Extensions Project", from Seth Schoen, John Gilmore, Dave Täht, et al.

Doomseeker's IP2C code treated 127.0.0.0/8 specially: Servers from those
addresses would get assigned a special "Localhost" flag, instead of
country data returned from IP2C lookups. Now we only return "Localhost"
flags servers for in the 127.0.0.0/16 network.

Fixes: #4010
See: https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-127/
---
 src/core/ip2c/ip2c.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/ip2c/ip2c.h b/src/core/ip2c/ip2c.h
index e5403867..11927578 100644
--- a/src/core/ip2c/ip2c.h
+++ b/src/core/ip2c/ip2c.h
@@ -177,7 +177,7 @@ private:
 	inline bool isLocalhostAddress(unsigned ipv4Address)
 	{
 		const static unsigned LOCALHOST_BEGIN = QHostAddress("127.0.0.0").toIPv4Address();
-		const static unsigned LOCALHOST_END = QHostAddress("127.255.255.255").toIPv4Address();
+		const static unsigned LOCALHOST_END = QHostAddress("127.0.255.255").toIPv4Address();
 
 		return ipv4Address >= LOCALHOST_BEGIN && ipv4Address <= LOCALHOST_END;
 	}
-- 
2.36.1