[test] test that an invalid GETDATA doesn't prevent processing of future messages

Co-Authored-By: John Newbery <john@johnnewbery.com>

test/functional/p2p_getdata.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 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 GETDATA processing behavior"""
+from collections import defaultdict
+
+from test_framework.messages import (
+    CInv,
+    msg_getdata,
+)
+from test_framework.mininode import (
+    mininode_lock,
+    P2PInterface,
+)
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import wait_until
+
+class P2PStoreBlock(P2PInterface):
+
+    def __init__(self):
+        super().__init__()
+        self.blocks = defaultdict(int)
+
+    def on_block(self, message):
+        message.block.calc_sha256()
+        self.blocks[message.block.sha256] += 1
+
+class GetdataTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+
+    def run_test(self):
+        self.nodes[0].add_p2p_connection(P2PStoreBlock())
+
+        self.log.info("test that an invalid GETDATA doesn't prevent processing of future messages")
+
+        # Send invalid message and verify that node responds to later ping
+        invalid_getdata = msg_getdata()
+        invalid_getdata.inv.append(CInv(t=0, h=0))  # INV type 0 is invalid.
+        self.nodes[0].p2ps[0].send_and_ping(invalid_getdata)
+
+        # Check getdata still works by fetching tip block
+        best_block = int(self.nodes[0].getbestblockhash(), 16)
+        good_getdata = msg_getdata()
+        good_getdata.inv.append(CInv(t=2, h=best_block))
+        self.nodes[0].p2ps[0].send_and_ping(good_getdata)
+        wait_until(lambda: self.nodes[0].p2ps[0].blocks[best_block] == 1, timeout=30, lock=mininode_lock)
+
+if __name__ == '__main__':
+    GetdataTest().main()

test/functional/test_runner.py

@@ -151,6 +151,7 @@ BASE_SCRIPTS = [
     'rpc_deprecated.py',
     'wallet_disable.py',
     'p2p_addr_relay.py',
+    'p2p_getdata.py',
     'rpc_net.py',
     'wallet_keypool.py',
     'wallet_keypool.py --descriptors',