From aee50849ad5983ec4ce66ad42a390b186a173bed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustaf=20Alh=C3=A4ll?= <gustaf@hanicef.me>
Date: Wed, 29 Jan 2025 18:51:53 +0100
Subject: [PATCH] Fix port collision on IPv6 connections

---
 src/netcode/i_tcp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/netcode/i_tcp.c b/src/netcode/i_tcp.c
index 256d9992e..fbe7ec4d2 100644
--- a/src/netcode/i_tcp.c
+++ b/src/netcode/i_tcp.c
@@ -456,6 +456,8 @@ static boolean SOCK_cmpipv6(mysockaddr_t *a, mysockaddr_t *b, UINT8 mask)
 {
 	UINT8 bitmask;
 	I_Assert(mask <= 128);
+	if (mask == 0)
+		mask = 128;
 	if (memcmp(&a->ip6.sin6_addr.s6_addr, &b->ip6.sin6_addr.s6_addr, mask / 8) != 0)
 		return false;
 	if (mask % 8 == 0)