test: p2p: check limited peers desirability (depending on best block …

…depth)

This adds coverage for the logic introduced in PR #28170
("p2p: adaptive connections services flags").

test/functional/p2p_handshake.py

@@ -6,10 +6,12 @@
 Test P2P behaviour during the handshake phase (VERSION, VERACK messages).
 """
 import itertools
+import time
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.messages import (
     NODE_NETWORK,
+    NODE_NETWORK_LIMITED,
     NODE_NONE,
     NODE_P2P_V2,
     NODE_WITNESS,
@@ -60,6 +62,12 @@ def run_test(self):
         self.test_desirable_service_flags(node, [NODE_NONE, NODE_NETWORK, NODE_WITNESS], expect_disconnect=True)
         self.test_desirable_service_flags(node, [NODE_NETWORK | NODE_WITNESS], expect_disconnect=False)
 
+        self.log.info("Check that limited peers are only desired if the local chain is close to the tip (<24h)")
+        node.setmocktime(int(time.time()) + 25 * 3600)  # tip outside the 24h window, should fail
+        self.test_desirable_service_flags(node, [NODE_NETWORK_LIMITED | NODE_WITNESS], expect_disconnect=True)
+        node.setmocktime(int(time.time()) + 23 * 3600)  # tip inside the 24h window, should succeed
+        self.test_desirable_service_flags(node, [NODE_NETWORK_LIMITED | NODE_WITNESS], expect_disconnect=False)
+
         self.log.info("Check that feeler connections get disconnected immediately")
         with node.assert_debug_log([f"feeler connection completed"]):
             self.add_outbound_connection(node, "feeler", NODE_NONE, wait_for_disconnect=True)