Merge bitcoin#27712: test: p2p: check misbehavior for non-continuous headers messages

a97c59f test: p2p: check misbehavior for non-continuous headers messages (Sebastian Falbesoner)

Pull request description:

  This PR adds missing test coverage for a peer sending a `headers` message where the headers don't connect to each other, which should be treated as misbehaving (not disconnecting though, as the score increase is only 20). The relevant code path is `PeerManagerImpl::ProcessHeadersMessage` -> `PeerManagerImpl::CheckHeadersPoW` -> `PeerManagerImpl::CheckHeadersAreContinuous`:

  https://github.com/bitcoin/bitcoin/blob/17acb2782a66f033238340e4fb81009e7f79e97a/src/net_processing.cpp#L2415-L2419

  https://github.com/bitcoin/bitcoin/blob/17acb2782a66f033238340e4fb81009e7f79e97a/src/net_processing.cpp#L2474-L2484

ACKs for top commit:
  sr-gi:
    ACK bitcoin@a97c59f
  achow101:
    ACK a97c59f
  instagibbs:
    ACK a97c59f

Tree-SHA512: 3f8d6a2492e5c8b63c7b11be2e4ec455f83581b2c58f2d4e705baadfe8d7c6377296d6cd0eda679d291a13d8930b09443f8e3d183795df34b780c703d5d3aeb3

Author: achow101

test/functional/p2p_invalid_messages.py

@@ -4,6 +4,8 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test node responses to invalid network messages."""
 
+import random
+
 
 from test_framework.messages import (
     CBlockHeader,
@@ -61,7 +63,7 @@ def run_test(self):
         self.test_oversized_inv_msg()
         self.test_oversized_getdata_msg()
         self.test_oversized_headers_msg()
-        self.test_resource_exhaustion()
+        self.test_noncontinuous_headers_msg()
 
     def test_buffer(self):
         self.log.info("Test message with header split across two buffers is received")
@@ -186,6 +188,25 @@ def test_oversized_headers2_msg(self):
         size = MAX_HEADERS_COMPRESSED_RESULT + 1
         self.test_oversized_msg(msg_headers2([CBlockHeader()] * size), size)
 
+    def test_noncontinuous_headers_msg(self):
+        self.log.info("Test headers message with non-continuous headers sequence is logged as misbehaving")
+        block_hashes = self.generate(self.nodes[0], 10)
+        block_headers = []
+        for block_hash in block_hashes:
+            block_headers.append(from_hex(CBlockHeader(), self.nodes[0].getblockheader(block_hash, False)))
+
+        # continuous headers sequence should be fine
+        MISBEHAVING_NONCONTINUOUS_HEADERS_MSGS = ['Misbehaving', 'non-continuous headers sequence']
+        peer = self.nodes[0].add_p2p_connection(P2PInterface())
+        with self.nodes[0].assert_debug_log([], unexpected_msgs=MISBEHAVING_NONCONTINUOUS_HEADERS_MSGS):
+            peer.send_and_ping(msg_headers(block_headers))
+
+        # delete arbitrary block header somewhere in the middle to break link
+        del block_headers[random.randrange(1, len(block_headers)-1)]
+        with self.nodes[0].assert_debug_log(expected_msgs=MISBEHAVING_NONCONTINUOUS_HEADERS_MSGS):
+            peer.send_and_ping(msg_headers(block_headers))
+        self.nodes[0].disconnect_p2ps()
+
     def test_resource_exhaustion(self):
         self.log.info("Test node stays up despite many large junk messages")
         # Don't use v2 here - the non-optimised encryption would take too long to encrypt