Merge #29984: net: Replace ifname check with IFF_LOOPBACK in Discover

a68fed1 net: Fix misleading comment for Discover (laanwj) 7766dd2 net: Replace ifname check with IFF_LOOPBACK in Discover (laanwj) Pull request description: 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. Also remove a misleading comment in Discover's doc comment. ACKs for top commit: sipa: utACK a68fed1 willcl-ark: utACK a68fed1 theuni: utACK a68fed1. Satoshi-era brittleness :) Tree-SHA512: e2d7fc541f40f6a6af08286e7bcb0873ff55debdcd8b38b03f274897b673a6fb51d84d6c7241a02a9567ddf2645f50231d91bb1f55307ba7c6e68196c29b0edf
bitcoin · May 7, 2024 · ef09f53 · ef09f53
2 parents 63d0b93 + a68fed1
commit ef09f53
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Showing 2 changed files with 2 additions and 4 deletions.
diff --git a/src/net.cpp b/src/net.cpp
@@ -3113,8 +3113,7 @@ 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);

diff --git a/src/net.h b/src/net.h
@@ -137,8 +137,7 @@ struct CSerializedNetMsg {
 /**
  * Look up IP addresses from all interfaces on the machine and add them to the
  * list of local addresses to self-advertise.
- * The loopback interface is skipped and only the first address from each
- * interface is used.
+ * The loopback interface is skipped.
  */
 void Discover();