test: p2p: check disconnect due to lack of desirable service flags

Author: theStack

test/functional/p2p_handshake.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+# Copyright (c) 2024 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""
+Test P2P behaviour during the handshake phase (VERSION, VERACK messages).
+"""
+import random
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.messages import (
+    NODE_NETWORK,
+    NODE_WITNESS,
+)
+from test_framework.p2p import P2PInterface
+
+
+DESIRABLE_SERVICE_FLAGS = NODE_NETWORK | NODE_WITNESS
+
+
+class P2PHandshakeTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+
+    def run_test(self):
+        node = self.nodes[0]
+        self.log.info("Check that lacking desired service flags leads to disconnect")
+        for i, conn_type in enumerate(["outbound-full-relay", "block-relay-only", "addr-fetch"]):
+            services = random.choice([0, NODE_NETWORK, NODE_WITNESS])
+            assert (services & DESIRABLE_SERVICE_FLAGS) != DESIRABLE_SERVICE_FLAGS
+            expected_debug_log = f'peer={i} does not offer the expected services ' \
+                    f'({services:08x} offered, {DESIRABLE_SERVICE_FLAGS:08x} expected)'
+            self.log.info(f'    - services 0x{services:08x}, type "{conn_type}"')
+            with node.assert_debug_log([expected_debug_log]):
+                peer = node.add_outbound_p2p_connection(P2PInterface(), wait_for_verack=False, p2p_idx=i,
+                                                        connection_type=conn_type, services=services)
+                peer.wait_for_disconnect()
+
+        self.log.info("Check that feeler connections get disconnected immediately")
+        with node.assert_debug_log(["feeler connection completed"]):
+            peer = node.add_outbound_p2p_connection(P2PInterface(), p2p_idx=i+1, connection_type="feeler", services=0)
+            peer.wait_for_disconnect()
+
+
+if __name__ == '__main__':
+    P2PHandshakeTest().main()