rpc: addpeeraddress: throw on invalid IP

Throw RPC_CLIENT_INVALID_IP_OR_SUBNET when LookupHost(addr, false) fails
in addpeeraddress. This aligns with setban/addconnection and avoids the
opaque {"success": false} result for input errors. The JSON {success,
error?} object remains for addrman outcomes only. Update test to match.

Author: john-moffett

src/rpc/net.cpp

@@ -1000,26 +1000,28 @@ static RPCHelpMan addpeeraddress()
 
     UniValue obj(UniValue::VOBJ);
     std::optional<CNetAddr> net_addr{LookupHost(addr_string, false)};
+    if (!net_addr.has_value()) {
+        throw JSONRPCError(RPC_CLIENT_INVALID_IP_OR_SUBNET, "Invalid IP address");
+    }
+
     bool success{false};
 
-    if (net_addr.has_value()) {
-        CService service{net_addr.value(), port};
-        CAddress address{MaybeFlipIPv6toCJDNS(service), ServiceFlags{NODE_NETWORK | NODE_WITNESS}};
-        address.nTime = Now<NodeSeconds>();
-        // The source address is set equal to the address. This is equivalent to the peer
-        // announcing itself.
-        if (addrman.Add({address}, address)) {
-            success = true;
-            if (tried) {
-                // Attempt to move the address to the tried addresses table.
-                if (!addrman.Good(address)) {
-                    success = false;
-                    obj.pushKV("error", "failed-adding-to-tried");
-                }
+    CService service{net_addr.value(), port};
+    CAddress address{MaybeFlipIPv6toCJDNS(service), ServiceFlags{NODE_NETWORK | NODE_WITNESS}};
+    address.nTime = Now<NodeSeconds>();
+    // The source address is set equal to the address. This is equivalent to the peer
+    // announcing itself.
+    if (addrman.Add({address}, address)) {
+        success = true;
+        if (tried) {
+            // Attempt to move the address to the tried addresses table.
+            if (!addrman.Good(address)) {
+                success = false;
+                obj.pushKV("error", "failed-adding-to-tried");
             }
-        } else {
-            obj.pushKV("error", "failed-adding-to-new");
         }
+    } else {
+        obj.pushKV("error", "failed-adding-to-new");
     }
 
     obj.pushKV("success", success);

test/functional/rpc_net.py

@@ -344,9 +344,12 @@ def test_addpeeraddress(self):
         assert "unknown command: addpeeraddress" not in node.help("addpeeraddress")
 
         self.log.debug("Test that adding an empty address fails")
-        assert_equal(node.addpeeraddress(address="", port=8333), {"success": False})
+        assert_raises_rpc_error(-30, "Invalid IP address", node.addpeeraddress, address="", port=8333)
         assert_equal(node.getnodeaddresses(count=0), [])
 
+        self.log.debug("Test that adding a non-IP/hostname fails (no DNS lookup allowed)")
+        assert_raises_rpc_error(-30, "Invalid IP address", node.addpeeraddress, address="not_an_ip", port=8333)
+
         self.log.debug("Test that non-bool tried fails")
         assert_raises_rpc_error(-3, "JSON value of type string is not of expected type bool", self.nodes[0].addpeeraddress, address="1.2.3.4", tried="True", port=1234)