text: #!/usr/bin/env python3
  # Copyright (c) 2015-2020 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 node responses to invalid network messages."""
  
  import struct
  import time
  
  from test_framework.messages import (
      CBlockHeader,
      CInv,
      MAX_HEADERS_RESULTS,
      MAX_INV_SIZE,
      MAX_PROTOCOL_MESSAGE_LENGTH,
      msg_getdata,
      msg_headers,
      msg_inv,
      msg_ping,
      MSG_TX,
      ser_string,
  )
  from test_framework.p2p import (
      P2PDataStore,
      P2PInterface,
  )
  from test_framework.test_framework import eTitaniumTestFramework
  from test_framework.util import (
      assert_equal,
      hex_str_to_bytes,
  )
  
  VALID_DATA_LIMIT = MAX_PROTOCOL_MESSAGE_LENGTH - 5  # Account for the 5-byte length prefix
  
  
  class msg_unrecognized:
      """Nonsensical message. Modeled after similar types in test_framework.messages."""
  
      msgtype = b'badmsg'
  
      def __init__(self, *, str_data):
          self.str_data = str_data.encode() if not isinstance(str_data, bytes) else str_data
  
      def serialize(self):
          return ser_string(self.str_data)
  
      def __repr__(self):
          return "{}(data={})".format(self.msgtype, self.str_data)
  
  
  class SenderOfAddrV2(P2PInterface):
      def wait_for_sendaddrv2(self):
          self.wait_until(lambda: 'sendaddrv2' in self.last_message)
  
  
  class InvalidMessagesTest(eTitaniumTestFramework):
      def set_test_params(self):
          self.num_nodes = 1
          self.setup_clean_chain = True
  
      def run_test(self):
          self.test_buffer()
          self.test_magic_bytes()
          self.test_checksum()
          self.test_size()
          self.test_msgtype()
          self.test_addrv2_empty()
          self.test_addrv2_no_addresses()
          self.test_addrv2_too_long_address()
          self.test_addrv2_unrecognized_network()
          self.test_oversized_inv_msg()
          self.test_oversized_getdata_msg()
          self.test_oversized_headers_msg()
          self.test_resource_exhaustion()
  
      def test_buffer(self):
          self.log.info("Test message with header split across two buffers is received")
          conn = self.nodes[0].add_p2p_connection(P2PDataStore())
          # Create valid message
          msg = conn.build_message(msg_ping(nonce=12345))
          cut_pos = 12  # Chosen at an arbitrary position within the header
          # Send message in two pieces
          before = self.nodes[0].getnettotals()['totalbytesrecv']
          conn.send_raw_message(msg[:cut_pos])
          # Wait until node has processed the first half of the message
          self.wait_until(lambda: self.nodes[0].getnettotals()['totalbytesrecv'] != before)
          middle = self.nodes[0].getnettotals()['totalbytesrecv']
          # If this assert fails, we've hit an unlikely race
          # where the test framework sent a message in between the two halves
          assert_equal(middle, before + cut_pos)
          conn.send_raw_message(msg[cut_pos:])
          conn.sync_with_ping(timeout=1)
          self.nodes[0].disconnect_p2ps()
  
      def test_magic_bytes(self):
          self.log.info("Test message with invalid magic bytes disconnects peer")
          conn = self.nodes[0].add_p2p_connection(P2PDataStore())
          with self.nodes[0].assert_debug_log(['HEADER ERROR - MESSAGESTART (badmsg, 2 bytes), received ffffffff']):
              msg = conn.build_message(msg_unrecognized(str_data="d"))
              # modify magic bytes
              msg = b'\xff' * 4 + msg[4:]
              conn.send_raw_message(msg)
              conn.wait_for_disconnect(timeout=1)
          self.nodes[0].disconnect_p2ps()
  
      def test_checksum(self):
          self.log.info("Test message with invalid checksum logs an error")
          conn = self.nodes[0].add_p2p_connection(P2PDataStore())
          with self.nodes[0].assert_debug_log(['CHECKSUM ERROR (badmsg, 2 bytes), expected 78df0a04 was ffffffff']):
              msg = conn.build_message(msg_unrecognized(str_data="d"))
              # Checksum is after start bytes (4B), message type (12B), len (4B)
              cut_len = 4 + 12 + 4
              # modify checksum
              msg = msg[:cut_len] + b'\xff' * 4 + msg[cut_len + 4:]
              conn.send_raw_message(msg)
              conn.sync_with_ping(timeout=1)
          # Check that traffic is accounted for (24 bytes header + 2 bytes payload)
          assert_equal(self.nodes[0].getpeerinfo()[0]['bytesrecv_per_msg']['*other*'], 26)
          self.nodes[0].disconnect_p2ps()
  
      def test_size(self):
          self.log.info("Test message with oversized payload disconnects peer")
          conn = self.nodes[0].add_p2p_connection(P2PDataStore())
          with self.nodes[0].assert_debug_log(['HEADER ERROR - SIZE (badmsg, 4000001 bytes)']):
              msg = msg_unrecognized(str_data="d" * (VALID_DATA_LIMIT + 1))
              msg = conn.build_message(msg)
              conn.send_raw_message(msg)
              conn.wait_for_disconnect(timeout=1)
          self.nodes[0].disconnect_p2ps()
  
      def test_msgtype(self):
          self.log.info("Test message with invalid message type logs an error")
          conn = self.nodes[0].add_p2p_connection(P2PDataStore())
          with self.nodes[0].assert_debug_log(['HEADER ERROR - COMMAND']):
              msg = msg_unrecognized(str_data="d")
              msg = conn.build_message(msg)
              # Modify msgtype
              msg = msg[:7] + b'\x00' + msg[7 + 1:]
              conn.send_raw_message(msg)
              conn.sync_with_ping(timeout=1)
          # Check that traffic is accounted for (24 bytes header + 2 bytes payload)
          assert_equal(self.nodes[0].getpeerinfo()[0]['bytesrecv_per_msg']['*other*'], 26)
          self.nodes[0].disconnect_p2ps()
  
      def test_addrv2(self, label, required_log_messages, raw_addrv2):
          node = self.nodes[0]
          conn = node.add_p2p_connection(SenderOfAddrV2())
  
          # Make sure etitaniumd signals support for ADDRv2, otherwise this test
          # will bombard an old node with messages it does not recognize which
          # will produce unexpected results.
          conn.wait_for_sendaddrv2()
  
          self.log.info('Test addrv2: ' + label)
  
          msg = msg_unrecognized(str_data=b'')
          msg.msgtype = b'addrv2'
          with node.assert_debug_log(required_log_messages):
              # override serialize() which would include the length of the data
              msg.serialize = lambda: raw_addrv2
              conn.send_raw_message(conn.build_message(msg))
              conn.sync_with_ping()
  
          node.disconnect_p2ps()
  
      def test_addrv2_empty(self):
          self.test_addrv2('empty',
              [
                  'received: addrv2 (0 bytes)',
                  'ProcessMessages(addrv2, 0 bytes): Exception',
                  'end of data',
              ],
              b'')
  
      def test_addrv2_no_addresses(self):
          self.test_addrv2('no addresses',
              [
                  'received: addrv2 (1 bytes)',
              ],
              hex_str_to_bytes('00'))
  
      def test_addrv2_too_long_address(self):
          self.test_addrv2('too long address',
              [
                  'received: addrv2 (525 bytes)',
                  'ProcessMessages(addrv2, 525 bytes): Exception',
                  'Address too long: 513 > 512',
              ],
              hex_str_to_bytes(
                  '01' +       # number of entries
                  '61bc6649' + # time, Fri Jan  9 02:54:25 UTC 2009
                  '00' +       # service flags, COMPACTSIZE(NODE_NONE)
                  '01' +       # network type (IPv4)
                  'fd0102' +   # address length (COMPACTSIZE(513))
                  'ab' * 513 + # address
                  '208d'))     # port
  
      def test_addrv2_unrecognized_network(self):
          now_hex = struct.pack('<I', int(time.time())).hex()
          self.test_addrv2('unrecognized network',
              [
                  'received: addrv2 (25 bytes)',
                  'IP 9.9.9.9 mapped',
                  'Added 1 addresses',
              ],
              hex_str_to_bytes(
                  '02' +     # number of entries
                  # this should be ignored without impeding acceptance of subsequent ones
                  now_hex +  # time
                  '01' +     # service flags, COMPACTSIZE(NODE_NETWORK)
                  '99' +     # network type (unrecognized)
                  '02' +     # address length (COMPACTSIZE(2))
                  'ab' * 2 + # address
                  '208d' +   # port
                  # this should be added:
                  now_hex +  # time
                  '01' +     # service flags, COMPACTSIZE(NODE_NETWORK)
                  '01' +     # network type (IPv4)
                  '04' +     # address length (COMPACTSIZE(4))
                  '09' * 4 + # address
                  '208d'))   # port
  
      def test_oversized_msg(self, msg, size):
          msg_type = msg.msgtype.decode('ascii')
          self.log.info("Test {} message of size {} is logged as misbehaving".format(msg_type, size))
          with self.nodes[0].assert_debug_log(['Misbehaving', '{} message size = {}'.format(msg_type, size)]):
              self.nodes[0].add_p2p_connection(P2PInterface()).send_and_ping(msg)
          self.nodes[0].disconnect_p2ps()
  
      def test_oversized_inv_msg(self):
          size = MAX_INV_SIZE + 1
          self.test_oversized_msg(msg_inv([CInv(MSG_TX, 1)] * size), size)
  
      def test_oversized_getdata_msg(self):
          size = MAX_INV_SIZE + 1
          self.test_oversized_msg(msg_getdata([CInv(MSG_TX, 1)] * size), size)
  
      def test_oversized_headers_msg(self):
          size = MAX_HEADERS_RESULTS + 1
          self.test_oversized_msg(msg_headers([CBlockHeader()] * size), size)
  
      def test_resource_exhaustion(self):
          self.log.info("Test node stays up despite many large junk messages")
          conn = self.nodes[0].add_p2p_connection(P2PDataStore())
          conn2 = self.nodes[0].add_p2p_connection(P2PDataStore())
          msg_at_size = msg_unrecognized(str_data="b" * VALID_DATA_LIMIT)
          assert len(msg_at_size.serialize()) == MAX_PROTOCOL_MESSAGE_LENGTH
  
          self.log.info("(a) Send 80 messages, each of maximum valid data size (4MB)")
          for _ in range(80):
              conn.send_message(msg_at_size)
  
          # Check that, even though the node is being hammered by nonsense from one
          # connection, it can still service other peers in a timely way.
          self.log.info("(b) Check node still services peers in a timely way")
          for _ in range(20):
              conn2.sync_with_ping(timeout=2)
  
          self.log.info("(c) Wait for node to drop junk messages, while remaining connected")
          conn.sync_with_ping(timeout=400)
  
          # Despite being served up a bunch of nonsense, the peers should still be connected.
          assert conn.is_connected
          assert conn2.is_connected
          self.nodes[0].disconnect_p2ps()
  
  
  if __name__ == '__main__':
      InvalidMessagesTest().main()
  