Merge bitcoin#29356: test: make v2transport arg in addconnection mandatory and few cleanups

e7fd70f [test] make v2transport arg in addconnection mandatory and few cleanups (stratospher)

Pull request description:

  - make `v2transport` argument in `addconnection` regression-testing only RPC mandatory. bitcoin#24748 (comment)
  - previously it was an optional arg with default `false` value.
  - only place this RPC is used is in the [functional tests](https://github.com/bitcoin/bitcoin/blob/11b436a66af3ceaebb0f907878715f331516a0bc/test/functional/test_framework/test_node.py#L742) where we always pass the appropriate `v2transport` option to the RPC anyways. (and that too just for python dummy peer(`P2PInterface`) and bitcoind(`TestNode`) interactions)
  - rename `v2_handshake()` to `_on_data_v2_handshake()` bitcoin#24748 (comment)
  - more compact return statement in `wait_for_reconnect()` bitcoin#24748 (comment)
  - assertion to check that empty version packets are received from `TestNode`.

ACKs for top commit:
  glozow:
    ACK e7fd70f
  theStack:
    Code-review ACK e7fd70f
  mzumsande:
    Code Review ACK e7fd70f

Tree-SHA512: e66e29baccd91e1e4398b91f7d45c5fc7c2841d77d8a6178734586017bf2be63496721649da91848dec71da605ee31664352407d5bb896e624cc693767c61a1f

Author: glozow

Diff for: src/rpc/net.cpp

@@ -371,7 +371,7 @@ static RPCHelpMan addconnection()
         {
             {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The IP address and port to attempt connecting to."},
             {"connection_type", RPCArg::Type::STR, RPCArg::Optional::NO, "Type of connection to open (\"outbound-full-relay\", \"block-relay-only\", \"addr-fetch\" or \"feeler\")."},
-            {"v2transport", RPCArg::Type::BOOL, RPCArg::Default{false}, "Attempt to connect using BIP324 v2 transport protocol"},
+            {"v2transport", RPCArg::Type::BOOL, RPCArg::Optional::NO, "Attempt to connect using BIP324 v2 transport protocol"},
         },
         RPCResult{
             RPCResult::Type::OBJ, "", "",
@@ -403,7 +403,7 @@ static RPCHelpMan addconnection()
     } else {
         throw JSONRPCError(RPC_INVALID_PARAMETER, self.ToString());
     }
-    bool use_v2transport = !request.params[2].isNull() && request.params[2].get_bool();
+    bool use_v2transport = self.Arg<bool>(2);
 
     NodeContext& node = EnsureAnyNodeContext(request.context);
     CConnman& connman = EnsureConnman(node);

Diff for: test/functional/feature_anchors.py

@@ -99,7 +99,7 @@ def run_test(self):
         self.restart_node(0, extra_args=[f"-onion={onion_conf.addr[0]}:{onion_conf.addr[1]}"])
 
         self.log.info("Add 256-bit-address block-relay-only connections to node")
-        self.nodes[0].addconnection(ONION_ADDR, 'block-relay-only')
+        self.nodes[0].addconnection(ONION_ADDR, 'block-relay-only', v2transport=False)
 
         self.log.debug("Stop node")
         with self.nodes[0].assert_debug_log([f"DumpAnchors: Flush 1 outbound block-relay-only peer addresses to anchors.dat"]):

Diff for: test/functional/test_framework/p2p.py

@@ -242,7 +242,7 @@ def connection_lost(self, exc):
         self.on_close()
 
     # v2 handshake method
-    def v2_handshake(self):
+    def _on_data_v2_handshake(self):
         """v2 handshake performed before P2P messages are exchanged (see BIP324). P2PConnection is the initiator
         (in inbound connections to TestNode) and the responder (in outbound connections from TestNode).
         Performed by:
@@ -298,7 +298,7 @@ def data_received(self, t):
         if len(t) > 0:
             self.recvbuf += t
             if self.supports_v2_p2p and not self.v2_state.tried_v2_handshake:
-                self.v2_handshake()
+                self._on_data_v2_handshake()
             else:
                 self._on_data()
 
@@ -595,9 +595,7 @@ def wait_for_disconnect(self, timeout=60):
 
     def wait_for_reconnect(self, timeout=60):
         def test_function():
-            if not (self.is_connected and self.last_message.get('version') and self.v2_state is None):
-                return False
-            return True
+            return self.is_connected and self.last_message.get('version') and not self.supports_v2_p2p
         self.wait_until(test_function, timeout=timeout, check_connected=False)
 
     # Message receiving helper methods

Diff for: test/functional/test_framework/v2_p2p.py

@@ -220,6 +220,7 @@ def authenticate_handshake(self, response):
             # decoy packets have contents = None. v2 handshake is complete only when version packet
             # (can be empty with contents = b"") with contents != None is received.
             if contents is not None:
+                assert contents == b""  # currently TestNode sends an empty version packet
                 self.tried_v2_handshake = True
                 return processed_length, True
             response = response[length:]