net: only assume all local addresses if listening on any

If `-bind=` is provided then we would bind only to a particular address
and should not add all the other addresses of the machine to the list of
local addresses.

Fixes https://github.com/bitcoin/bitcoin/issues/20184 (case 4.)

2 files changed, 14 insertions, 2 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 05a8437043..a3d53c3fae 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1668,8 +1668,6 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     LogPrintf("nBestHeight = %d\n", chain_active_height);
     if (node.peerman) node.peerman->SetBestHeight(chain_active_height);
 
-    Discover();
-
     // Map ports with UPnP or NAT-PMP.
     StartMapPort(args.GetBoolArg("-upnp", DEFAULT_UPNP), gArgs.GetBoolArg("-natpmp", DEFAULT_NATPMP));
 
@@ -1762,6 +1760,12 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         StartTorControl(onion_service_target);
     }
 
+    if (connOptions.bind_on_any) {
+        // Only add all IP addresses of the machine if we would be listening on
+        // any address - 0.0.0.0 (IPv4) and :: (IPv6).
+        Discover();
+    }
+
     for (const auto& net : args.GetArgs("-whitelist")) {
         NetWhitelistPermissions subnet;
         bilingual_str error;
diff --git a/src/net.h b/src/net.h
index ddc1d3dd7c..a38310938b 100644
--- a/src/net.h
+++ b/src/net.h
@@ -183,7 +183,15 @@ enum class ConnectionType {
 
 /** Convert ConnectionType enum to a string value */
 std::string ConnectionTypeAsString(ConnectionType conn_type);
+
+/**
+ * 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.
+ */
 void Discover();
+
 uint16_t GetListenPort();
 
 enum