From 7766dd280d9a4a7ffdfcec58224d0985cfd4169b Mon Sep 17 00:00:00 2001
From: laanwj <126646+laanwj@users.noreply.github.com>
Date: Sun, 28 Apr 2024 11:35:27 +0200
Subject: [PATCH] net: Replace ifname check with IFF_LOOPBACK in Discover

Checking the interface name is kind of brittle. In the age of network
namespaces and containers, there is no reason a loopback interface can't
be called differently.

Check for the `IFF_LOOPBACK` flag to detect loopback interface instead.
---
 src/net.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/net.cpp b/src/net.cpp
index 4801f5c1f9c..7e60ef6df5d 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -3077,8 +3077,7 @@ void Discover()
         {
             if (ifa->ifa_addr == nullptr) continue;
             if ((ifa->ifa_flags & IFF_UP) == 0) continue;
-            if (strcmp(ifa->ifa_name, "lo") == 0) continue;
-            if (strcmp(ifa->ifa_name, "lo0") == 0) continue;
+            if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) continue;
             if (ifa->ifa_addr->sa_family == AF_INET)
             {
                 struct sockaddr_in* s4 = (struct sockaddr_in*)(ifa->ifa_addr);