diff --git a/test/functional/interface_rest.py b/test/functional/interface_rest.py
index 1e968f31c..c031dac0b 100755
--- a/test/functional/interface_rest.py
+++ b/test/functional/interface_rest.py
@@ -1,379 +1,386 @@
 #!/usr/bin/env python3
 # Copyright (c) 2014-2019 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 the REST API."""
 
 import binascii
 from decimal import Decimal
 from enum import Enum
 import http.client
 from io import BytesIO
 import json
 from struct import pack, unpack
 import urllib.parse
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
     assert_greater_than,
     assert_greater_than_or_equal,
     hex_str_to_bytes,
 )
 
+from test_framework.messages import BLOCK_HEADER_SIZE
+
 
 class ReqType(Enum):
     JSON = 1
     BIN = 2
     HEX = 3
 
 
 class RetType(Enum):
     OBJ = 1
     BYTES = 2
     JSON = 3
 
 
 def filter_output_indices_by_value(vouts, value):
     for vout in vouts:
         if vout['value'] == value:
             yield vout['n']
 
 
 class RESTTest (BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
         self.extra_args = [["-rest"], []]
 
     def skip_test_if_missing_module(self):
         self.skip_if_no_wallet()
 
     def test_rest_request(self, uri, http_method='GET', req_type=ReqType.JSON,
                           body='', status=200, ret_type=RetType.JSON):
         rest_uri = '/rest' + uri
         if req_type == ReqType.JSON:
             rest_uri += '.json'
         elif req_type == ReqType.BIN:
             rest_uri += '.bin'
         elif req_type == ReqType.HEX:
             rest_uri += '.hex'
 
         conn = http.client.HTTPConnection(self.url.hostname, self.url.port)
         self.log.debug('{} {} {}'.format(http_method, rest_uri, body))
         if http_method == 'GET':
             conn.request('GET', rest_uri)
         elif http_method == 'POST':
             conn.request('POST', rest_uri, body)
         resp = conn.getresponse()
 
         assert_equal(resp.status, status)
 
         if ret_type == RetType.OBJ:
             return resp
         elif ret_type == RetType.BYTES:
             return resp.read()
         elif ret_type == RetType.JSON:
             return json.loads(resp.read().decode('utf-8'), parse_float=Decimal)
 
     def run_test(self):
         self.url = urllib.parse.urlparse(self.nodes[0].url)
         self.log.info("Mine blocks and send Bitcoin Cash to node 1")
 
         # Random address so node1's balance doesn't increase
         not_related_address = "2MxqoHEdNQTyYeX1mHcbrrpzgojbosTpCvJ"
 
         self.nodes[0].generate(1)
         self.sync_all()
         self.nodes[1].generatetoaddress(100, not_related_address)
         self.sync_all()
 
         assert_equal(self.nodes[0].getbalance(), 50)
 
         txid = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.1)
         self.sync_all()
 
         self.log.info("Test the /tx URI")
 
         json_obj = self.test_rest_request("/tx/{}".format(txid))
         assert_equal(json_obj['txid'], txid)
 
         # Check hex format response
         hex_response = self.test_rest_request(
             "/tx/{}".format(txid), req_type=ReqType.HEX, ret_type=RetType.OBJ)
         assert_greater_than_or_equal(int(hex_response.getheader('content-length')),
                                      json_obj['size'] * 2)
 
         # Get the vin to later check for utxo (should be spent by then)
         spent = (json_obj['vin'][0]['txid'], json_obj['vin'][0]['vout'])
         # Get n of 0.1 outpoint
         n, = filter_output_indices_by_value(json_obj['vout'], Decimal('0.1'))
         spending = (txid, n)
 
         self.log.info("Query an unspent TXO using the /getutxos URI")
 
         self.nodes[1].generatetoaddress(1, not_related_address)
         self.sync_all()
         bb_hash = self.nodes[0].getbestblockhash()
 
         assert_equal(self.nodes[1].getbalance(), Decimal("0.1"))
 
         # Check chainTip response
         json_obj = self.test_rest_request("/getutxos/{}-{}".format(*spending))
         assert_equal(json_obj['chaintipHash'], bb_hash)
 
         # Make sure there is one utxo
         assert_equal(len(json_obj['utxos']), 1)
         assert_equal(json_obj['utxos'][0]['value'], Decimal('0.1'))
 
         self.log.info("Query a spent TXO using the /getutxos URI")
 
         json_obj = self.test_rest_request("/getutxos/{}-{}".format(*spent))
 
         # Check chainTip response
         assert_equal(json_obj['chaintipHash'], bb_hash)
 
         # Make sure there is no utxo in the response because this outpoint has
         # been spent
         assert_equal(len(json_obj['utxos']), 0)
 
         # Check bitmap
         assert_equal(json_obj['bitmap'], "0")
 
         self.log.info("Query two TXOs using the /getutxos URI")
 
         json_obj = self.test_rest_request(
             "/getutxos/{}-{}/{}-{}".format(*(spending + spent)))
 
         assert_equal(len(json_obj['utxos']), 1)
         assert_equal(json_obj['bitmap'], "10")
 
         self.log.info(
             "Query the TXOs using the /getutxos URI with a binary response")
 
         bin_request = b'\x01\x02'
         for txid, n in [spending, spent]:
             bin_request += hex_str_to_bytes(txid)
             bin_request += pack("i", n)
 
         bin_response = self.test_rest_request(
             "/getutxos", http_method='POST', req_type=ReqType.BIN, body=bin_request, ret_type=RetType.BYTES)
         output = BytesIO(bin_response)
         chain_height, = unpack("i", output.read(4))
         response_hash = output.read(32)[::-1].hex()
 
         # Check if getutxo's chaintip during calculation was fine
         assert_equal(bb_hash, response_hash)
         # Chain height must be 102
         assert_equal(chain_height, 102)
 
         self.log.info("Test the /getutxos URI with and without /checkmempool")
         # Create a transaction, check that it's found with /checkmempool, but
         # not found without. Then confirm the transaction and check that it's
         # found with or without /checkmempool.
 
         # Do a tx and don't sync
         txid = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.1)
         json_obj = self.test_rest_request("/tx/{}".format(txid))
         # Get the spent output to later check for utxo (should be spent by
         # then)
         spent = (json_obj['vin'][0]['txid'], json_obj['vin'][0]['vout'])
         # Get n of 0.1 outpoint
         n, = filter_output_indices_by_value(json_obj['vout'], Decimal('0.1'))
         spending = (txid, n)
 
         json_obj = self.test_rest_request("/getutxos/{}-{}".format(*spending))
         assert_equal(len(json_obj['utxos']), 0)
 
         json_obj = self.test_rest_request(
             "/getutxos/checkmempool/{}-{}".format(*spending))
         assert_equal(len(json_obj['utxos']), 1)
 
         json_obj = self.test_rest_request("/getutxos/{}-{}".format(*spent))
         assert_equal(len(json_obj['utxos']), 1)
 
         json_obj = self.test_rest_request(
             "/getutxos/checkmempool/{}-{}".format(*spent))
         assert_equal(len(json_obj['utxos']), 0)
 
         self.nodes[0].generate(1)
         self.sync_all()
 
         json_obj = self.test_rest_request("/getutxos/{}-{}".format(*spending))
         assert_equal(len(json_obj['utxos']), 1)
 
         json_obj = self.test_rest_request(
             "/getutxos/checkmempool/{}-{}".format(*spending))
         assert_equal(len(json_obj['utxos']), 1)
 
         # Do some invalid requests
         self.test_rest_request("/getutxos", http_method='POST', req_type=ReqType.JSON,
                                body='{"checkmempool', status=400, ret_type=RetType.OBJ)
         self.test_rest_request("/getutxos", http_method='POST', req_type=ReqType.BIN,
                                body='{"checkmempool', status=400, ret_type=RetType.OBJ)
         self.test_rest_request("/getutxos/checkmempool", http_method='POST',
                                req_type=ReqType.JSON, status=400, ret_type=RetType.OBJ)
 
         # Test limits
         long_uri = '/'.join(["{}-{}".format(txid, n_) for n_ in range(20)])
         self.test_rest_request("/getutxos/checkmempool/{}".format(long_uri),
                                http_method='POST', status=400, ret_type=RetType.OBJ)
 
         long_uri = '/'.join(['{}-{}'.format(txid, n_) for n_ in range(15)])
         self.test_rest_request(
             "/getutxos/checkmempool/{}".format(long_uri), http_method='POST', status=200)
 
         # Generate block to not affect upcoming tests
         self.nodes[0].generate(
             1)
         self.sync_all()
 
         self.log.info("Test the /block, /blockhashbyheight and /headers URIs")
         bb_hash = self.nodes[0].getbestblockhash()
 
         # Check binary format
         response = self.test_rest_request(
             "/block/{}".format(bb_hash), req_type=ReqType.BIN, ret_type=RetType.OBJ)
-        assert_greater_than(int(response.getheader('content-length')), 80)
+        assert_greater_than(int(response.getheader(
+            'content-length')), BLOCK_HEADER_SIZE)
         response_bytes = response.read()
 
         # Compare with block header
         response_header = self.test_rest_request(
             "/headers/1/{}".format(bb_hash), req_type=ReqType.BIN, ret_type=RetType.OBJ)
-        assert_equal(int(response_header.getheader('content-length')), 80)
+        assert_equal(int(response_header.getheader(
+            'content-length')), BLOCK_HEADER_SIZE)
         response_header_bytes = response_header.read()
-        assert_equal(response_bytes[0:80], response_header_bytes)
+        assert_equal(
+            response_bytes[0:BLOCK_HEADER_SIZE], response_header_bytes)
 
         # Check block hex format
         response_hex = self.test_rest_request(
             "/block/{}".format(bb_hash), req_type=ReqType.HEX, ret_type=RetType.OBJ)
-        assert_greater_than(int(response_hex.getheader('content-length')), 160)
+        assert_greater_than(int(response_hex.getheader(
+            'content-length')), BLOCK_HEADER_SIZE * 2)
         response_hex_bytes = response_hex.read().strip(b'\n')
         assert_equal(binascii.hexlify(response_bytes), response_hex_bytes)
 
         # Compare with hex block header
         response_header_hex = self.test_rest_request(
             "/headers/1/{}".format(bb_hash), req_type=ReqType.HEX, ret_type=RetType.OBJ)
         assert_greater_than(
-            int(response_header_hex.getheader('content-length')), 160)
-        response_header_hex_bytes = response_header_hex.read(160)
+            int(response_header_hex.getheader('content-length')), BLOCK_HEADER_SIZE * 2)
+        response_header_hex_bytes = response_header_hex.read(
+            BLOCK_HEADER_SIZE * 2)
         assert_equal(binascii.hexlify(
-            response_bytes[:80]), response_header_hex_bytes)
+            response_bytes[:BLOCK_HEADER_SIZE]), response_header_hex_bytes)
 
         # Check json format
         block_json_obj = self.test_rest_request("/block/{}".format(bb_hash))
         assert_equal(block_json_obj['hash'], bb_hash)
         assert_equal(self.test_rest_request(
             "/blockhashbyheight/{}".format(block_json_obj['height']))['blockhash'], bb_hash)
 
         # Check hex/bin format
         resp_hex = self.test_rest_request(
             "/blockhashbyheight/{}".format(
                 block_json_obj['height']),
             req_type=ReqType.HEX,
             ret_type=RetType.OBJ)
         assert_equal(resp_hex.read().decode('utf-8').rstrip(), bb_hash)
         resp_bytes = self.test_rest_request(
             "/blockhashbyheight/{}".format(
                 block_json_obj['height']),
             req_type=ReqType.BIN,
             ret_type=RetType.BYTES)
         blockhash = binascii.hexlify(resp_bytes[::-1]).decode('utf-8')
         assert_equal(blockhash, bb_hash)
 
         # Check invalid blockhashbyheight requests
         resp = self.test_rest_request(
             "/blockhashbyheight/abc",
             ret_type=RetType.OBJ,
             status=400)
         assert_equal(
             resp.read().decode('utf-8').rstrip(),
             "Invalid height: abc")
         resp = self.test_rest_request(
             "/blockhashbyheight/1000000",
             ret_type=RetType.OBJ,
             status=404)
         assert_equal(
             resp.read().decode('utf-8').rstrip(),
             "Block height out of range")
         resp = self.test_rest_request(
             "/blockhashbyheight/-1",
             ret_type=RetType.OBJ,
             status=400)
         assert_equal(
             resp.read().decode('utf-8').rstrip(),
             "Invalid height: -1")
         self.test_rest_request(
             "/blockhashbyheight/",
             ret_type=RetType.OBJ,
             status=400)
 
         # Compare with json block header
         json_obj = self.test_rest_request("/headers/1/{}".format(bb_hash))
         # Ensure that there is one header in the json response
         assert_equal(len(json_obj), 1)
         # Request/response hash should be the same
         assert_equal(json_obj[0]['hash'], bb_hash)
 
         # Compare with normal RPC block response
         rpc_block_json = self.nodes[0].getblock(bb_hash)
         for key in ['hash', 'confirmations', 'height', 'version', 'merkleroot',
                     'time', 'nonce', 'bits', 'difficulty', 'chainwork', 'previousblockhash']:
             assert_equal(json_obj[0][key], rpc_block_json[key])
 
         # See if we can get 5 headers in one response
         self.nodes[1].generate(5)
         self.sync_all()
         json_obj = self.test_rest_request("/headers/5/{}".format(bb_hash))
         # Now we should have 5 header objects
         assert_equal(len(json_obj), 5)
 
         self.log.info("Test tx inclusion in the /mempool and /block URIs")
 
         # Make 3 tx and mine them on node 1
         txs = []
         txs.append(self.nodes[0].sendtoaddress(not_related_address, 11))
         txs.append(self.nodes[0].sendtoaddress(not_related_address, 11))
         txs.append(self.nodes[0].sendtoaddress(not_related_address, 11))
         self.sync_all()
 
         # Check that there are exactly 3 transactions in the TX memory pool
         # before generating the block
         json_obj = self.test_rest_request("/mempool/info")
         assert_equal(json_obj['size'], 3)
         # The size of the memory pool should be greater than 3x ~100 bytes
         assert_greater_than(json_obj['bytes'], 300)
 
         # Check that there are our submitted transactions in the TX memory pool
         json_obj = self.test_rest_request("/mempool/contents")
         for i, tx in enumerate(txs):
             assert tx in json_obj
             assert_equal(json_obj[tx]['spentby'], txs[i + 1:i + 2])
             assert_equal(json_obj[tx]['depends'], txs[i - 1:i])
 
         # Now mine the transactions
         newblockhash = self.nodes[1].generate(1)
         self.sync_all()
 
         # Check if the 3 tx show up in the new block
         json_obj = self.test_rest_request("/block/{}".format(newblockhash[0]))
         non_coinbase_txs = {tx['txid']
                             for tx in json_obj['tx'] if 'coinbase' not in tx['vin'][0]}
         assert_equal(non_coinbase_txs, set(txs))
 
         # Check the same but without tx details
         json_obj = self.test_rest_request(
             "/block/notxdetails/{}".format(newblockhash[0]))
         for tx in txs:
             assert tx in json_obj['tx']
 
         self.log.info("Test the /chaininfo URI")
 
         bb_hash = self.nodes[0].getbestblockhash()
 
         json_obj = self.test_rest_request("/chaininfo")
         assert_equal(json_obj['bestblockhash'], bb_hash)
 
 
 if __name__ == '__main__':
     RESTTest().main()
diff --git a/test/functional/mining_basic.py b/test/functional/mining_basic.py
index ebedb484e..a221aecae 100755
--- a/test/functional/mining_basic.py
+++ b/test/functional/mining_basic.py
@@ -1,299 +1,299 @@
 #!/usr/bin/env python3
 # Copyright (c) 2014-2019 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 mining RPCs
 
 - getmininginfo
 - getblocktemplate proposal mode
 - submitblock"""
 
 import copy
 from decimal import Decimal
 
 from test_framework.blocktools import (
     create_coinbase,
     TIME_GENESIS_BLOCK,
 )
 from test_framework.messages import (
     CBlock,
     CBlockHeader,
+    BLOCK_HEADER_SIZE,
 )
 from test_framework.mininode import (
     P2PDataStore,
 )
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
     assert_raises_rpc_error,
     connect_nodes,
 )
 from test_framework.script import CScriptNum
 
 
 def assert_template(node, block, expect, rehash=True):
     if rehash:
         block.hashMerkleRoot = block.calc_merkle_root()
     rsp = node.getblocktemplate(
         template_request={
             'data': block.serialize().hex(),
             'mode': 'proposal'})
     assert_equal(rsp, expect)
 
 
 class MiningTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = True
 
     def mine_chain(self):
         self.log.info('Create some old blocks')
         node = self.nodes[0]
         address = node.get_deterministic_priv_key().address
         for t in range(TIME_GENESIS_BLOCK,
                        TIME_GENESIS_BLOCK + 200 * 600, 600):
             node.setmocktime(t)
             node.generatetoaddress(1, address)
         mining_info = node.getmininginfo()
         assert_equal(mining_info['blocks'], 200)
         assert_equal(mining_info['currentblocktx'], 0)
         assert_equal(mining_info['currentblocksize'], 1000)
         self.restart_node(0)
         connect_nodes(self.nodes[0], self.nodes[1])
 
     def run_test(self):
         self.mine_chain()
         node = self.nodes[0]
 
         def assert_submitblock(block, result_str_1, result_str_2=None):
             block.solve()
             result_str_2 = result_str_2 or 'duplicate-invalid'
             assert_equal(result_str_1, node.submitblock(
                 hexdata=block.serialize().hex()))
             assert_equal(result_str_2, node.submitblock(
                 hexdata=block.serialize().hex()))
 
         self.log.info('getmininginfo')
         mining_info = node.getmininginfo()
         assert_equal(mining_info['blocks'], 200)
         assert_equal(mining_info['chain'], 'regtest')
         assert 'currentblocktx' not in mining_info
         assert 'currentblocksize' not in mining_info
         assert_equal(mining_info['difficulty'],
                      Decimal('4.656542373906925E-10'))
         assert_equal(mining_info['networkhashps'],
                      Decimal('0.003333333333333334'))
         assert_equal(mining_info['pooledtx'], 0)
 
         # Mine a block to leave initial block download
         node.generatetoaddress(1, node.get_deterministic_priv_key().address)
         tmpl = node.getblocktemplate()
         self.log.info("getblocktemplate: Test capability advertised")
         assert 'proposal' in tmpl['capabilities']
 
         next_height = int(tmpl["height"])
         coinbase_tx = create_coinbase(height=next_height)
         # sequence numbers must not be max for nLockTime to have effect
         coinbase_tx.vin[0].nSequence = 2 ** 32 - 2
         coinbase_tx.rehash()
 
         # round-trip the encoded bip34 block height commitment
         assert_equal(
             CScriptNum.decode(
                 coinbase_tx.vin[0].scriptSig),
             next_height)
         # round-trip negative and multi-byte CScriptNums to catch python
         # regression
         assert_equal(
             CScriptNum.decode(
                 CScriptNum.encode(
                     CScriptNum(1500))),
             1500)
         assert_equal(CScriptNum.decode(
             CScriptNum.encode(CScriptNum(-1500))), -1500)
         assert_equal(CScriptNum.decode(CScriptNum.encode(CScriptNum(-1))), -1)
 
         block = CBlock()
         block.nVersion = tmpl["version"]
         block.hashPrevBlock = int(tmpl["previousblockhash"], 16)
         block.nTime = tmpl["curtime"]
         block.nBits = int(tmpl["bits"], 16)
         block.nNonce = 0
         block.vtx = [coinbase_tx]
 
         self.log.info("getblocktemplate: Test valid block")
         assert_template(node, block, None)
 
         self.log.info("submitblock: Test block decode failure")
         assert_raises_rpc_error(-22, "Block decode failed",
                                 node.submitblock, block.serialize()[:-15].hex())
 
         self.log.info(
             "getblocktemplate: Test bad input hash for coinbase transaction")
         bad_block = copy.deepcopy(block)
         bad_block.vtx[0].vin[0].prevout.hash += 1
         bad_block.vtx[0].rehash()
         assert_template(node, bad_block, 'bad-cb-missing')
 
         self.log.info("submitblock: Test invalid coinbase transaction")
         assert_raises_rpc_error(-22, "Block does not start with a coinbase",
                                 node.submitblock, bad_block.serialize().hex())
 
         self.log.info("getblocktemplate: Test truncated final transaction")
         assert_raises_rpc_error(-22, "Block decode failed", node.getblocktemplate, {
                                 'data': block.serialize()[:-1].hex(), 'mode': 'proposal'})
 
         self.log.info("getblocktemplate: Test duplicate transaction")
         bad_block = copy.deepcopy(block)
         bad_block.vtx.append(bad_block.vtx[0])
         assert_template(node, bad_block, 'bad-txns-duplicate')
         assert_submitblock(bad_block, 'bad-txns-duplicate',
                            'bad-txns-duplicate')
 
         self.log.info("getblocktemplate: Test invalid transaction")
         bad_block = copy.deepcopy(block)
         bad_tx = copy.deepcopy(bad_block.vtx[0])
         bad_tx.vin[0].prevout.hash = 255
         bad_tx.rehash()
         bad_block.vtx.append(bad_tx)
         assert_template(node, bad_block, 'bad-txns-inputs-missingorspent')
         assert_submitblock(bad_block, 'bad-txns-inputs-missingorspent')
 
         self.log.info("getblocktemplate: Test nonfinal transaction")
         bad_block = copy.deepcopy(block)
         bad_block.vtx[0].nLockTime = 2 ** 32 - 1
         bad_block.vtx[0].rehash()
         assert_template(node, bad_block, 'bad-txns-nonfinal')
         assert_submitblock(bad_block, 'bad-txns-nonfinal')
 
         self.log.info("getblocktemplate: Test bad tx count")
         # The tx count is immediately after the block header
-        TX_COUNT_OFFSET = 80
         bad_block_sn = bytearray(block.serialize())
-        assert_equal(bad_block_sn[TX_COUNT_OFFSET], 1)
-        bad_block_sn[TX_COUNT_OFFSET] += 1
+        assert_equal(bad_block_sn[BLOCK_HEADER_SIZE], 1)
+        bad_block_sn[BLOCK_HEADER_SIZE] += 1
         assert_raises_rpc_error(-22, "Block decode failed", node.getblocktemplate, {
                                 'data': bad_block_sn.hex(), 'mode': 'proposal'})
 
         self.log.info("getblocktemplate: Test bad bits")
         bad_block = copy.deepcopy(block)
         bad_block.nBits = 469762303  # impossible in the real world
         assert_template(node, bad_block, 'bad-diffbits')
 
         self.log.info("getblocktemplate: Test bad merkle root")
         bad_block = copy.deepcopy(block)
         bad_block.hashMerkleRoot += 1
         assert_template(node, bad_block, 'bad-txnmrklroot', False)
         assert_submitblock(bad_block, 'bad-txnmrklroot', 'bad-txnmrklroot')
 
         self.log.info("getblocktemplate: Test bad timestamps")
         bad_block = copy.deepcopy(block)
         bad_block.nTime = 2 ** 31 - 1
         assert_template(node, bad_block, 'time-too-new')
         assert_submitblock(bad_block, 'time-too-new', 'time-too-new')
         bad_block.nTime = 0
         assert_template(node, bad_block, 'time-too-old')
         assert_submitblock(bad_block, 'time-too-old', 'time-too-old')
 
         self.log.info("getblocktemplate: Test not best block")
         bad_block = copy.deepcopy(block)
         bad_block.hashPrevBlock = 123
         assert_template(node, bad_block, 'inconclusive-not-best-prevblk')
         assert_submitblock(bad_block, 'prev-blk-not-found',
                            'prev-blk-not-found')
 
         self.log.info('submitheader tests')
         assert_raises_rpc_error(-22, 'Block header decode failed',
-                                lambda: node.submitheader(hexdata='xx' * 80))
+                                lambda: node.submitheader(hexdata='xx' * BLOCK_HEADER_SIZE))
         assert_raises_rpc_error(-22, 'Block header decode failed',
-                                lambda: node.submitheader(hexdata='ff' * 78))
+                                lambda: node.submitheader(hexdata='ff' * (BLOCK_HEADER_SIZE - 2)))
         assert_raises_rpc_error(-25, 'Must submit previous header',
-                                lambda: node.submitheader(hexdata='ff' * 80))
+                                lambda: node.submitheader(hexdata=super(CBlock, bad_block).serialize().hex()))
 
         block.nTime += 1
         block.solve()
 
         def chain_tip(b_hash, *, status='headers-only', branchlen=1):
             return {'hash': b_hash, 'height': 202,
                     'branchlen': branchlen, 'status': status}
 
         assert chain_tip(block.hash) not in node.getchaintips()
         node.submitheader(hexdata=block.serialize().hex())
         assert chain_tip(block.hash) in node.getchaintips()
         # Noop
         node.submitheader(hexdata=CBlockHeader(block).serialize().hex())
         assert chain_tip(block.hash) in node.getchaintips()
 
         bad_block_root = copy.deepcopy(block)
         bad_block_root.hashMerkleRoot += 2
         bad_block_root.solve()
         assert chain_tip(bad_block_root.hash) not in node.getchaintips()
         node.submitheader(hexdata=CBlockHeader(
             bad_block_root).serialize().hex())
         assert chain_tip(bad_block_root.hash) in node.getchaintips()
         # Should still reject invalid blocks, even if we have the header:
         assert_equal(node.submitblock(
             hexdata=bad_block_root.serialize().hex()), 'bad-txnmrklroot')
         assert_equal(node.submitblock(
             hexdata=bad_block_root.serialize().hex()), 'bad-txnmrklroot')
         assert chain_tip(bad_block_root.hash) in node.getchaintips()
         # We know the header for this invalid block, so should just return
         # early without error:
         node.submitheader(hexdata=CBlockHeader(
             bad_block_root).serialize().hex())
         assert chain_tip(bad_block_root.hash) in node.getchaintips()
 
         bad_block_lock = copy.deepcopy(block)
         bad_block_lock.vtx[0].nLockTime = 2**32 - 1
         bad_block_lock.vtx[0].rehash()
         bad_block_lock.hashMerkleRoot = bad_block_lock.calc_merkle_root()
         bad_block_lock.solve()
         assert_equal(node.submitblock(
             hexdata=bad_block_lock.serialize().hex()), 'bad-txns-nonfinal')
         assert_equal(node.submitblock(
             hexdata=bad_block_lock.serialize().hex()), 'duplicate-invalid')
         # Build a "good" block on top of the submitted bad block
         bad_block2 = copy.deepcopy(block)
         bad_block2.hashPrevBlock = bad_block_lock.sha256
         bad_block2.solve()
         assert_raises_rpc_error(-25, 'bad-prevblk', lambda: node.submitheader(
             hexdata=CBlockHeader(bad_block2).serialize().hex()))
 
         # Should reject invalid header right away
         bad_block_time = copy.deepcopy(block)
         bad_block_time.nTime = 1
         bad_block_time.solve()
         assert_raises_rpc_error(-25, 'time-too-old', lambda: node.submitheader(
             hexdata=CBlockHeader(bad_block_time).serialize().hex()))
 
         # Should ask for the block from a p2p node, if they announce the header
         # as well:
         node.add_p2p_connection(P2PDataStore())
         # Drop the first getheaders
         node.p2p.wait_for_getheaders(timeout=5)
         node.p2p.send_blocks_and_test(blocks=[block], node=node)
         # Must be active now:
         assert chain_tip(block.hash, status='active',
                          branchlen=0) in node.getchaintips()
 
         # Building a few blocks should give the same results
         node.generatetoaddress(10, node.get_deterministic_priv_key().address)
         assert_raises_rpc_error(-25, 'time-too-old', lambda: node.submitheader(
             hexdata=CBlockHeader(bad_block_time).serialize().hex()))
         assert_raises_rpc_error(-25, 'bad-prevblk', lambda: node.submitheader(
             hexdata=CBlockHeader(bad_block2).serialize().hex()))
         node.submitheader(hexdata=CBlockHeader(block).serialize().hex())
         node.submitheader(hexdata=CBlockHeader(
             bad_block_root).serialize().hex())
         # valid
         assert_equal(node.submitblock(
             hexdata=block.serialize().hex()), 'duplicate')
 
         # Sanity check that maxtries supports large integers
         node.generatetoaddress(
             1, node.get_deterministic_priv_key().address, pow(
                 2, 32))
 
 
 if __name__ == '__main__':
     MiningTest().main()
diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
index e22dff5bd..ecd4c3c98 100755
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -1,1563 +1,1568 @@
 #!/usr/bin/env python3
 # Copyright (c) 2010 ArtForz -- public domain half-a-node
 # Copyright (c) 2012 Jeff Garzik
 # Copyright (c) 2010-2019 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Bitcoin test framework primitive and message structures
 
 CBlock, CTransaction, CBlockHeader, CTxIn, CTxOut, etc....:
     data structures that should map to corresponding structures in
     bitcoin/primitives
 
 msg_block, msg_tx, msg_headers, etc.:
     data structures that represent network messages
 
 ser_*, deser_*: functions that handle serialization/deserialization.
 
 Classes use __slots__ to ensure extraneous attributes aren't accidentally added
 by tests, compromising their intended effect.
 """
 from codecs import encode
 import copy
 import hashlib
 from io import BytesIO
 import random
 import socket
 import struct
 import time
 
 from test_framework.siphash import siphash256
-from test_framework.util import hex_str_to_bytes
+from test_framework.util import hex_str_to_bytes, assert_equal
+
 
 MIN_VERSION_SUPPORTED = 60001
 # past bip-31 for ping/pong
 MY_VERSION = 70014
 MY_SUBVERSION = b"/python-mininode-tester:0.0.3/"
 # from version 70001 onwards, fRelay should be appended to version
 # messages (BIP37)
 MY_RELAY = 1
 
 MAX_INV_SZ = 50000
 MAX_LOCATOR_SZ = 101
 MAX_BLOCK_BASE_SIZE = 1000000
 
 # 1 BCH in satoshis
 COIN = 100000000
 
 NODE_NETWORK = (1 << 0)
 # NODE_GETUTXO = (1 << 1)
 NODE_BLOOM = (1 << 2)
 # NODE_WITNESS = (1 << 3)
 NODE_XTHIN = (1 << 4)
 NODE_BITCOIN_CASH = (1 << 5)
 NODE_NETWORK_LIMITED = (1 << 10)
 NODE_AVALANCHE = (1 << 24)
 
 MSG_TX = 1
 MSG_BLOCK = 2
 MSG_FILTERED_BLOCK = 3
 MSG_CMPCTBLOCK = 4
 MSG_TYPE_MASK = 0xffffffff >> 2
 
 # Serialization/deserialization tools
 
 
 def sha256(s):
     return hashlib.new('sha256', s).digest()
 
 
 def ripemd160(s):
     return hashlib.new('ripemd160', s).digest()
 
 
 def hash256(s):
     return sha256(sha256(s))
 
 
 def ser_compact_size(size):
     r = b""
     if size < 253:
         r = struct.pack("B", size)
     elif size < 0x10000:
         r = struct.pack("<BH", 253, size)
     elif size < 0x100000000:
         r = struct.pack("<BI", 254, size)
     else:
         r = struct.pack("<BQ", 255, size)
     return r
 
 
 def deser_compact_size(f):
     nit = struct.unpack("<B", f.read(1))[0]
     if nit == 253:
         nit = struct.unpack("<H", f.read(2))[0]
     elif nit == 254:
         nit = struct.unpack("<I", f.read(4))[0]
     elif nit == 255:
         nit = struct.unpack("<Q", f.read(8))[0]
     return nit
 
 
 def deser_string(f):
     nit = deser_compact_size(f)
     return f.read(nit)
 
 
 def ser_string(s):
     return ser_compact_size(len(s)) + s
 
 
 def deser_uint256(f):
     r = 0
     for i in range(8):
         t = struct.unpack("<I", f.read(4))[0]
         r += t << (i * 32)
     return r
 
 
 def ser_uint256(u):
     rs = b""
     for i in range(8):
         rs += struct.pack("<I", u & 0xFFFFFFFF)
         u >>= 32
     return rs
 
 
 def uint256_from_str(s):
     r = 0
     t = struct.unpack("<IIIIIIII", s[:32])
     for i in range(8):
         r += t[i] << (i * 32)
     return r
 
 
 def uint256_from_compact(c):
     nbytes = (c >> 24) & 0xFF
     v = (c & 0xFFFFFF) << (8 * (nbytes - 3))
     return v
 
 
 def deser_vector(f, c):
     nit = deser_compact_size(f)
     r = []
     for i in range(nit):
         t = c()
         t.deserialize(f)
         r.append(t)
     return r
 
 
 # ser_function_name: Allow for an alternate serialization function on the
 # entries in the vector.
 def ser_vector(v, ser_function_name=None):
     r = ser_compact_size(len(v))
     for i in v:
         if ser_function_name:
             r += getattr(i, ser_function_name)()
         else:
             r += i.serialize()
     return r
 
 
 def deser_uint256_vector(f):
     nit = deser_compact_size(f)
     r = []
     for i in range(nit):
         t = deser_uint256(f)
         r.append(t)
     return r
 
 
 def ser_uint256_vector(v):
     r = ser_compact_size(len(v))
     for i in v:
         r += ser_uint256(i)
     return r
 
 
 def deser_string_vector(f):
     nit = deser_compact_size(f)
     r = []
     for i in range(nit):
         t = deser_string(f)
         r.append(t)
     return r
 
 
 def ser_string_vector(v):
     r = ser_compact_size(len(v))
     for sv in v:
         r += ser_string(sv)
     return r
 
 
 # Deserialize from a hex string representation (eg from RPC)
 
 
 def FromHex(obj, hex_string):
     obj.deserialize(BytesIO(hex_str_to_bytes(hex_string)))
     return obj
 
 # Convert a binary-serializable object to hex (eg for submission via RPC)
 
 
 def ToHex(obj):
     return obj.serialize().hex()
 
 # Objects that map to bitcoind objects, which can be serialized/deserialized
 
 
 class CAddress:
     __slots__ = ("ip", "nServices", "pchReserved", "port", "time")
 
     def __init__(self):
         self.time = 0
         self.nServices = 1
         self.pchReserved = b"\x00" * 10 + b"\xff" * 2
         self.ip = "0.0.0.0"
         self.port = 0
 
     def deserialize(self, f, with_time=True):
         if with_time:
             self.time = struct.unpack("<i", f.read(4))[0]
         self.nServices = struct.unpack("<Q", f.read(8))[0]
         self.pchReserved = f.read(12)
         self.ip = socket.inet_ntoa(f.read(4))
         self.port = struct.unpack(">H", f.read(2))[0]
 
     def serialize(self, with_time=True):
         r = b""
         if with_time:
             r += struct.pack("<i", self.time)
         r += struct.pack("<Q", self.nServices)
         r += self.pchReserved
         r += socket.inet_aton(self.ip)
         r += struct.pack(">H", self.port)
         return r
 
     def __repr__(self):
         return "CAddress(nServices={} ip={} port={})".format(
             self.nServices, self.ip, self.port)
 
 
 class CInv:
     __slots__ = ("hash", "type")
 
     typemap = {
         0: "Error",
         MSG_TX: "TX",
         MSG_BLOCK: "Block",
         MSG_FILTERED_BLOCK: "filtered Block",
         MSG_CMPCTBLOCK: "CompactBlock"
     }
 
     def __init__(self, t=0, h=0):
         self.type = t
         self.hash = h
 
     def deserialize(self, f):
         self.type = struct.unpack("<i", f.read(4))[0]
         self.hash = deser_uint256(f)
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.type)
         r += ser_uint256(self.hash)
         return r
 
     def __repr__(self):
         return "CInv(type={} hash={:064x})".format(
             self.typemap[self.type], self.hash)
 
 
 class CBlockLocator:
     __slots__ = ("nVersion", "vHave")
 
     def __init__(self):
         self.nVersion = MY_VERSION
         self.vHave = []
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
         self.vHave = deser_uint256_vector(f)
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.nVersion)
         r += ser_uint256_vector(self.vHave)
         return r
 
     def __repr__(self):
         return "CBlockLocator(nVersion={} vHave={})".format(
             self.nVersion, repr(self.vHave))
 
 
 class COutPoint:
     __slots__ = ("hash", "n")
 
     def __init__(self, hash=0, n=0):
         self.hash = hash
         self.n = n
 
     def deserialize(self, f):
         self.hash = deser_uint256(f)
         self.n = struct.unpack("<I", f.read(4))[0]
 
     def serialize(self):
         r = b""
         r += ser_uint256(self.hash)
         r += struct.pack("<I", self.n)
         return r
 
     def __repr__(self):
         return "COutPoint(hash={:064x} n={})".format(self.hash, self.n)
 
 
 class CTxIn:
     __slots__ = ("nSequence", "prevout", "scriptSig")
 
     def __init__(self, outpoint=None, scriptSig=b"", nSequence=0):
         if outpoint is None:
             self.prevout = COutPoint()
         else:
             self.prevout = outpoint
         self.scriptSig = scriptSig
         self.nSequence = nSequence
 
     def deserialize(self, f):
         self.prevout = COutPoint()
         self.prevout.deserialize(f)
         self.scriptSig = deser_string(f)
         self.nSequence = struct.unpack("<I", f.read(4))[0]
 
     def serialize(self):
         r = b""
         r += self.prevout.serialize()
         r += ser_string(self.scriptSig)
         r += struct.pack("<I", self.nSequence)
         return r
 
     def __repr__(self):
         return "CTxIn(prevout={} scriptSig={} nSequence={})".format(
             repr(self.prevout), self.scriptSig.hex(), self.nSequence)
 
 
 class CTxOut:
     __slots__ = ("nValue", "scriptPubKey")
 
     def __init__(self, nValue=0, scriptPubKey=b""):
         self.nValue = nValue
         self.scriptPubKey = scriptPubKey
 
     def deserialize(self, f):
         self.nValue = struct.unpack("<q", f.read(8))[0]
         self.scriptPubKey = deser_string(f)
 
     def serialize(self):
         r = b""
         r += struct.pack("<q", self.nValue)
         r += ser_string(self.scriptPubKey)
         return r
 
     def __repr__(self):
         return "CTxOut(nValue={}.{:08d} scriptPubKey={})".format(
             self.nValue // COIN, self.nValue % COIN, self.scriptPubKey.hex())
 
 
 class CTransaction:
     __slots__ = ("hash", "nLockTime", "nVersion", "sha256", "vin", "vout")
 
     def __init__(self, tx=None):
         if tx is None:
             self.nVersion = 1
             self.vin = []
             self.vout = []
             self.nLockTime = 0
             self.sha256 = None
             self.hash = None
         else:
             self.nVersion = tx.nVersion
             self.vin = copy.deepcopy(tx.vin)
             self.vout = copy.deepcopy(tx.vout)
             self.nLockTime = tx.nLockTime
             self.sha256 = tx.sha256
             self.hash = tx.hash
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
         self.vin = deser_vector(f, CTxIn)
         self.vout = deser_vector(f, CTxOut)
         self.nLockTime = struct.unpack("<I", f.read(4))[0]
         self.sha256 = None
         self.hash = None
 
     def billable_size(self):
         """
         Returns the size used for billing the against the transaction
         """
         return len(self.serialize())
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.nVersion)
         r += ser_vector(self.vin)
         r += ser_vector(self.vout)
         r += struct.pack("<I", self.nLockTime)
         return r
 
     # Recalculate the txid
     def rehash(self):
         self.sha256 = None
         self.calc_sha256()
         return self.hash
 
     # self.sha256 and self.hash -- those are expected to be the txid.
     def calc_sha256(self):
         if self.sha256 is None:
             self.sha256 = uint256_from_str(hash256(self.serialize()))
         self.hash = encode(
             hash256(self.serialize())[::-1], 'hex_codec').decode('ascii')
 
     def get_id(self):
         # For now, just forward the hash.
         self.calc_sha256()
         return self.hash
 
     def is_valid(self):
         self.calc_sha256()
         for tout in self.vout:
             if tout.nValue < 0 or tout.nValue > 21000000 * COIN:
                 return False
         return True
 
     def __repr__(self):
         return "CTransaction(nVersion={} vin={} vout={} nLockTime={})".format(
             self.nVersion, repr(self.vin), repr(self.vout), self.nLockTime)
 
 
 class CBlockHeader:
     __slots__ = ("hash", "hashMerkleRoot", "hashPrevBlock", "nBits", "nNonce",
                  "nTime", "nVersion", "sha256")
 
     def __init__(self, header=None):
         if header is None:
             self.set_null()
         else:
             self.nVersion = header.nVersion
             self.hashPrevBlock = header.hashPrevBlock
             self.hashMerkleRoot = header.hashMerkleRoot
             self.nTime = header.nTime
             self.nBits = header.nBits
             self.nNonce = header.nNonce
             self.sha256 = header.sha256
             self.hash = header.hash
             self.calc_sha256()
 
     def set_null(self):
         self.nVersion = 1
         self.hashPrevBlock = 0
         self.hashMerkleRoot = 0
         self.nTime = 0
         self.nBits = 0
         self.nNonce = 0
         self.sha256 = None
         self.hash = None
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
         self.hashPrevBlock = deser_uint256(f)
         self.hashMerkleRoot = deser_uint256(f)
         self.nTime = struct.unpack("<I", f.read(4))[0]
         self.nBits = struct.unpack("<I", f.read(4))[0]
         self.nNonce = struct.unpack("<I", f.read(4))[0]
         self.sha256 = None
         self.hash = None
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.nVersion)
         r += ser_uint256(self.hashPrevBlock)
         r += ser_uint256(self.hashMerkleRoot)
         r += struct.pack("<I", self.nTime)
         r += struct.pack("<I", self.nBits)
         r += struct.pack("<I", self.nNonce)
         return r
 
     def calc_sha256(self):
         if self.sha256 is None:
             r = b""
             r += struct.pack("<i", self.nVersion)
             r += ser_uint256(self.hashPrevBlock)
             r += ser_uint256(self.hashMerkleRoot)
             r += struct.pack("<I", self.nTime)
             r += struct.pack("<I", self.nBits)
             r += struct.pack("<I", self.nNonce)
             self.sha256 = uint256_from_str(hash256(r))
             self.hash = encode(hash256(r)[::-1], 'hex_codec').decode('ascii')
 
     def rehash(self):
         self.sha256 = None
         self.calc_sha256()
         return self.sha256
 
     def __repr__(self):
         return "CBlockHeader(nVersion={} hashPrevBlock={:064x} hashMerkleRoot={:064x} nTime={} nBits={:08x} nNonce={:08x})".format(
             self.nVersion, self.hashPrevBlock, self.hashMerkleRoot,
             self.nTime, self.nBits, self.nNonce)
 
 
+BLOCK_HEADER_SIZE = len(CBlockHeader().serialize())
+assert_equal(BLOCK_HEADER_SIZE, 80)
+
+
 class CBlock(CBlockHeader):
     __slots__ = ("vtx",)
 
     def __init__(self, header=None):
         super(CBlock, self).__init__(header)
         self.vtx = []
 
     def deserialize(self, f):
         super(CBlock, self).deserialize(f)
         self.vtx = deser_vector(f, CTransaction)
 
     def serialize(self):
         r = b""
         r += super(CBlock, self).serialize()
         r += ser_vector(self.vtx)
         return r
 
     # Calculate the merkle root given a vector of transaction hashes
     def get_merkle_root(self, hashes):
         while len(hashes) > 1:
             newhashes = []
             for i in range(0, len(hashes), 2):
                 i2 = min(i + 1, len(hashes) - 1)
                 newhashes.append(hash256(hashes[i] + hashes[i2]))
             hashes = newhashes
         return uint256_from_str(hashes[0])
 
     def calc_merkle_root(self):
         hashes = []
         for tx in self.vtx:
             tx.calc_sha256()
             hashes.append(ser_uint256(tx.sha256))
         return self.get_merkle_root(hashes)
 
     def is_valid(self):
         self.calc_sha256()
         target = uint256_from_compact(self.nBits)
         if self.sha256 > target:
             return False
         for tx in self.vtx:
             if not tx.is_valid():
                 return False
         if self.calc_merkle_root() != self.hashMerkleRoot:
             return False
         return True
 
     def solve(self):
         self.rehash()
         target = uint256_from_compact(self.nBits)
         while self.sha256 > target:
             self.nNonce += 1
             self.rehash()
 
     def __repr__(self):
         return "CBlock(nVersion={} hashPrevBlock={:064x} hashMerkleRoot={:064x} nTime={} nBits={:08x} nNonce={:08x} vtx={})".format(
             self.nVersion, self.hashPrevBlock, self.hashMerkleRoot,
             self.nTime, self.nBits, self.nNonce, repr(self.vtx))
 
 
 class PrefilledTransaction:
     __slots__ = ("index", "tx")
 
     def __init__(self, index=0, tx=None):
         self.index = index
         self.tx = tx
 
     def deserialize(self, f):
         self.index = deser_compact_size(f)
         self.tx = CTransaction()
         self.tx.deserialize(f)
 
     def serialize(self):
         r = b""
         r += ser_compact_size(self.index)
         r += self.tx.serialize()
         return r
 
     def __repr__(self):
         return "PrefilledTransaction(index={}, tx={})".format(
             self.index, repr(self.tx))
 
 
 # This is what we send on the wire, in a cmpctblock message.
 class P2PHeaderAndShortIDs:
     __slots__ = ("header", "nonce", "prefilled_txn", "prefilled_txn_length",
                  "shortids", "shortids_length")
 
     def __init__(self):
         self.header = CBlockHeader()
         self.nonce = 0
         self.shortids_length = 0
         self.shortids = []
         self.prefilled_txn_length = 0
         self.prefilled_txn = []
 
     def deserialize(self, f):
         self.header.deserialize(f)
         self.nonce = struct.unpack("<Q", f.read(8))[0]
         self.shortids_length = deser_compact_size(f)
         for i in range(self.shortids_length):
             # shortids are defined to be 6 bytes in the spec, so append
             # two zero bytes and read it in as an 8-byte number
             self.shortids.append(
                 struct.unpack("<Q", f.read(6) + b'\x00\x00')[0])
         self.prefilled_txn = deser_vector(f, PrefilledTransaction)
         self.prefilled_txn_length = len(self.prefilled_txn)
 
     def serialize(self):
         r = b""
         r += self.header.serialize()
         r += struct.pack("<Q", self.nonce)
         r += ser_compact_size(self.shortids_length)
         for x in self.shortids:
             # We only want the first 6 bytes
             r += struct.pack("<Q", x)[0:6]
         r += ser_vector(self.prefilled_txn)
         return r
 
     def __repr__(self):
         return "P2PHeaderAndShortIDs(header={}, nonce={}, shortids_length={}, shortids={}, prefilled_txn_length={}, prefilledtxn={}".format(
             repr(self.header), self.nonce, self.shortids_length,
             repr(self.shortids), self.prefilled_txn_length,
             repr(self.prefilled_txn))
 
 # Calculate the BIP 152-compact blocks shortid for a given transaction hash
 
 
 def calculate_shortid(k0, k1, tx_hash):
     expected_shortid = siphash256(k0, k1, tx_hash)
     expected_shortid &= 0x0000ffffffffffff
     return expected_shortid
 
 
 # This version gets rid of the array lengths, and reinterprets the differential
 # encoding into indices that can be used for lookup.
 class HeaderAndShortIDs:
     __slots__ = ("header", "nonce", "prefilled_txn", "shortids")
 
     def __init__(self, p2pheaders_and_shortids=None):
         self.header = CBlockHeader()
         self.nonce = 0
         self.shortids = []
         self.prefilled_txn = []
 
         if p2pheaders_and_shortids is not None:
             self.header = p2pheaders_and_shortids.header
             self.nonce = p2pheaders_and_shortids.nonce
             self.shortids = p2pheaders_and_shortids.shortids
             last_index = -1
             for x in p2pheaders_and_shortids.prefilled_txn:
                 self.prefilled_txn.append(
                     PrefilledTransaction(x.index + last_index + 1, x.tx))
                 last_index = self.prefilled_txn[-1].index
 
     def to_p2p(self):
         ret = P2PHeaderAndShortIDs()
         ret.header = self.header
         ret.nonce = self.nonce
         ret.shortids_length = len(self.shortids)
         ret.shortids = self.shortids
         ret.prefilled_txn_length = len(self.prefilled_txn)
         ret.prefilled_txn = []
         last_index = -1
         for x in self.prefilled_txn:
             ret.prefilled_txn.append(
                 PrefilledTransaction(x.index - last_index - 1, x.tx))
             last_index = x.index
         return ret
 
     def get_siphash_keys(self):
         header_nonce = self.header.serialize()
         header_nonce += struct.pack("<Q", self.nonce)
         hash_header_nonce_as_str = sha256(header_nonce)
         key0 = struct.unpack("<Q", hash_header_nonce_as_str[0:8])[0]
         key1 = struct.unpack("<Q", hash_header_nonce_as_str[8:16])[0]
         return [key0, key1]
 
     # Version 2 compact blocks use wtxid in shortids (rather than txid)
     def initialize_from_block(self, block, nonce=0, prefill_list=[0]):
         self.header = CBlockHeader(block)
         self.nonce = nonce
         self.prefilled_txn = [PrefilledTransaction(i, block.vtx[i])
                               for i in prefill_list]
         self.shortids = []
         [k0, k1] = self.get_siphash_keys()
         for i in range(len(block.vtx)):
             if i not in prefill_list:
                 tx_hash = block.vtx[i].sha256
                 self.shortids.append(calculate_shortid(k0, k1, tx_hash))
 
     def __repr__(self):
         return "HeaderAndShortIDs(header={}, nonce={}, shortids={}, prefilledtxn={}".format(
             repr(self.header), self.nonce, repr(self.shortids),
             repr(self.prefilled_txn))
 
 
 class BlockTransactionsRequest:
     __slots__ = ("blockhash", "indexes")
 
     def __init__(self, blockhash=0, indexes=None):
         self.blockhash = blockhash
         self.indexes = indexes if indexes is not None else []
 
     def deserialize(self, f):
         self.blockhash = deser_uint256(f)
         indexes_length = deser_compact_size(f)
         for i in range(indexes_length):
             self.indexes.append(deser_compact_size(f))
 
     def serialize(self):
         r = b""
         r += ser_uint256(self.blockhash)
         r += ser_compact_size(len(self.indexes))
         for x in self.indexes:
             r += ser_compact_size(x)
         return r
 
     # helper to set the differentially encoded indexes from absolute ones
     def from_absolute(self, absolute_indexes):
         self.indexes = []
         last_index = -1
         for x in absolute_indexes:
             self.indexes.append(x - last_index - 1)
             last_index = x
 
     def to_absolute(self):
         absolute_indexes = []
         last_index = -1
         for x in self.indexes:
             absolute_indexes.append(x + last_index + 1)
             last_index = absolute_indexes[-1]
         return absolute_indexes
 
     def __repr__(self):
         return "BlockTransactionsRequest(hash={:064x} indexes={})".format(
             self.blockhash, repr(self.indexes))
 
 
 class BlockTransactions:
     __slots__ = ("blockhash", "transactions")
 
     def __init__(self, blockhash=0, transactions=None):
         self.blockhash = blockhash
         self.transactions = transactions if transactions is not None else []
 
     def deserialize(self, f):
         self.blockhash = deser_uint256(f)
         self.transactions = deser_vector(f, CTransaction)
 
     def serialize(self):
         r = b""
         r += ser_uint256(self.blockhash)
         r += ser_vector(self.transactions)
         return r
 
     def __repr__(self):
         return "BlockTransactions(hash={:064x} transactions={})".format(
             self.blockhash, repr(self.transactions))
 
 
 class AvalanchePoll():
     __slots__ = ("round", "invs")
 
     def __init__(self, round=0, invs=None):
         self.round = round
         self.invs = invs if invs is not None else []
 
     def deserialize(self, f):
         self.round = struct.unpack("<q", f.read(8))[0]
         self.invs = deser_vector(f, CInv)
 
     def serialize(self):
         r = b""
         r += struct.pack("<q", self.round)
         r += ser_vector(self.invs)
         return r
 
     def __repr__(self):
         return "AvalanchePoll(round={}, invs={})".format(
             self.round, repr(self.invs))
 
 
 class AvalancheVote():
     __slots__ = ("error", "hash")
 
     def __init__(self, e=0, h=0):
         self.error = e
         self.hash = h
 
     def deserialize(self, f):
         self.error = struct.unpack("<i", f.read(4))[0]
         self.hash = deser_uint256(f)
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.error)
         r += ser_uint256(self.hash)
         return r
 
     def __repr__(self):
         return "AvalancheVote(error={}, hash={:064x})".format(
             self.error, self.hash)
 
 
 class AvalancheResponse():
     __slots__ = ("round", "cooldown", "votes")
 
     def __init__(self, round=0, cooldown=0, votes=None):
         self.round = round
         self.cooldown = cooldown
         self.votes = votes if votes is not None else []
 
     def deserialize(self, f):
         self.round = struct.unpack("<q", f.read(8))[0]
         self.cooldown = struct.unpack("<i", f.read(4))[0]
         self.votes = deser_vector(f, AvalancheVote)
 
     def serialize(self):
         r = b""
         r += struct.pack("<q", self.round)
         r += struct.pack("<i", self.cooldown)
         r += ser_vector(self.votes)
         return r
 
     def get_hash(self):
         return hash256(self.serialize())
 
     def __repr__(self):
         return "AvalancheResponse(round={}, cooldown={}, votes={})".format(
             self.round, self.cooldown, repr(self.votes))
 
 
 class TCPAvalancheResponse():
     __slots__ = ("response", "sig")
 
     def __init__(self, response=AvalancheResponse(), sig=b"\0" * 64):
         self.response = response
         self.sig = sig
 
     def deserialize(self, f):
         self.response.deserialize(f)
         self.sig = f.read(64)
 
     def serialize(self):
         r = b""
         r += self.response.serialize()
         r += self.sig
         return r
 
     def __repr__(self):
         return "TCPAvalancheResponse(response={}, sig={})".format(
             repr(self.response), self.sig)
 
 
 class CPartialMerkleTree:
     __slots__ = ("fBad", "nTransactions", "vBits", "vHash")
 
     def __init__(self):
         self.nTransactions = 0
         self.vHash = []
         self.vBits = []
         self.fBad = False
 
     def deserialize(self, f):
         self.nTransactions = struct.unpack("<i", f.read(4))[0]
         self.vHash = deser_uint256_vector(f)
         vBytes = deser_string(f)
         self.vBits = []
         for i in range(len(vBytes) * 8):
             self.vBits.append(vBytes[i // 8] & (1 << (i % 8)) != 0)
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.nTransactions)
         r += ser_uint256_vector(self.vHash)
         vBytesArray = bytearray([0x00] * ((len(self.vBits) + 7) // 8))
         for i in range(len(self.vBits)):
             vBytesArray[i // 8] |= self.vBits[i] << (i % 8)
         r += ser_string(bytes(vBytesArray))
         return r
 
     def __repr__(self):
         return "CPartialMerkleTree(nTransactions={}, vHash={}, vBits={})".format(
             self.nTransactions, repr(self.vHash), repr(self.vBits))
 
 
 class CMerkleBlock:
     __slots__ = ("header", "txn")
 
     def __init__(self):
         self.header = CBlockHeader()
         self.txn = CPartialMerkleTree()
 
     def deserialize(self, f):
         self.header.deserialize(f)
         self.txn.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.header.serialize()
         r += self.txn.serialize()
         return r
 
     def __repr__(self):
         return "CMerkleBlock(header={}, txn={})".format(
             repr(self.header), repr(self.txn))
 
 
 # Objects that correspond to messages on the wire
 
 
 class msg_version:
     __slots__ = ("addrFrom", "addrTo", "nNonce", "nRelay", "nServices",
                  "nStartingHeight", "nTime", "nVersion", "strSubVer")
     command = b"version"
 
     def __init__(self):
         self.nVersion = MY_VERSION
         self.nServices = 1
         self.nTime = int(time.time())
         self.addrTo = CAddress()
         self.addrFrom = CAddress()
         self.nNonce = random.getrandbits(64)
         self.strSubVer = MY_SUBVERSION
         self.nStartingHeight = -1
         self.nRelay = MY_RELAY
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
         self.nServices = struct.unpack("<Q", f.read(8))[0]
         self.nTime = struct.unpack("<q", f.read(8))[0]
         self.addrTo = CAddress()
         self.addrTo.deserialize(f, False)
 
         self.addrFrom = CAddress()
         self.addrFrom.deserialize(f, False)
         self.nNonce = struct.unpack("<Q", f.read(8))[0]
         self.strSubVer = deser_string(f)
 
         self.nStartingHeight = struct.unpack("<i", f.read(4))[0]
 
         if self.nVersion >= 70001:
             # Relay field is optional for version 70001 onwards
             try:
                 self.nRelay = struct.unpack("<b", f.read(1))[0]
             except Exception:
                 self.nRelay = 0
         else:
             self.nRelay = 0
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.nVersion)
         r += struct.pack("<Q", self.nServices)
         r += struct.pack("<q", self.nTime)
         r += self.addrTo.serialize(False)
         r += self.addrFrom.serialize(False)
         r += struct.pack("<Q", self.nNonce)
         r += ser_string(self.strSubVer)
         r += struct.pack("<i", self.nStartingHeight)
         r += struct.pack("<b", self.nRelay)
         return r
 
     def __repr__(self):
         return 'msg_version(nVersion={} nServices={} nTime={} addrTo={} addrFrom={} nNonce=0x{:016X} strSubVer={} nStartingHeight={} nRelay={})'.format(
             self.nVersion, self.nServices, self.nTime,
             repr(self.addrTo), repr(self.addrFrom), self.nNonce,
             self.strSubVer, self.nStartingHeight, self.nRelay)
 
 
 class msg_verack:
     __slots__ = ()
     command = b"verack"
 
     def __init__(self):
         pass
 
     def deserialize(self, f):
         pass
 
     def serialize(self):
         return b""
 
     def __repr__(self):
         return "msg_verack()"
 
 
 class msg_addr:
     __slots__ = ("addrs",)
     command = b"addr"
 
     def __init__(self):
         self.addrs = []
 
     def deserialize(self, f):
         self.addrs = deser_vector(f, CAddress)
 
     def serialize(self):
         return ser_vector(self.addrs)
 
     def __repr__(self):
         return "msg_addr(addrs={})".format(repr(self.addrs))
 
 
 class msg_inv:
     __slots__ = ("inv",)
     command = b"inv"
 
     def __init__(self, inv=None):
         if inv is None:
             self.inv = []
         else:
             self.inv = inv
 
     def deserialize(self, f):
         self.inv = deser_vector(f, CInv)
 
     def serialize(self):
         return ser_vector(self.inv)
 
     def __repr__(self):
         return "msg_inv(inv={})".format(repr(self.inv))
 
 
 class msg_getdata:
     __slots__ = ("inv",)
     command = b"getdata"
 
     def __init__(self, inv=None):
         self.inv = inv if inv is not None else []
 
     def deserialize(self, f):
         self.inv = deser_vector(f, CInv)
 
     def serialize(self):
         return ser_vector(self.inv)
 
     def __repr__(self):
         return "msg_getdata(inv={})".format(repr(self.inv))
 
 
 class msg_getblocks:
     __slots__ = ("locator", "hashstop")
     command = b"getblocks"
 
     def __init__(self):
         self.locator = CBlockLocator()
         self.hashstop = 0
 
     def deserialize(self, f):
         self.locator = CBlockLocator()
         self.locator.deserialize(f)
         self.hashstop = deser_uint256(f)
 
     def serialize(self):
         r = b""
         r += self.locator.serialize()
         r += ser_uint256(self.hashstop)
         return r
 
     def __repr__(self):
         return "msg_getblocks(locator={} hashstop={:064x})".format(
             repr(self.locator), self.hashstop)
 
 
 class msg_tx:
     __slots__ = ("tx",)
     command = b"tx"
 
     def __init__(self, tx=CTransaction()):
         self.tx = tx
 
     def deserialize(self, f):
         self.tx.deserialize(f)
 
     def serialize(self):
         return self.tx.serialize()
 
     def __repr__(self):
         return "msg_tx(tx={})".format(repr(self.tx))
 
 
 class msg_block:
     __slots__ = ("block",)
     command = b"block"
 
     def __init__(self, block=None):
         if block is None:
             self.block = CBlock()
         else:
             self.block = block
 
     def deserialize(self, f):
         self.block.deserialize(f)
 
     def serialize(self):
         return self.block.serialize()
 
     def __repr__(self):
         return "msg_block(block={})".format(repr(self.block))
 
 
 # for cases where a user needs tighter control over what is sent over the wire
 # note that the user must supply the name of the command, and the data
 
 
 class msg_generic:
     __slots__ = ("command", "data")
 
     def __init__(self, command, data=None):
         self.command = command
         self.data = data
 
     def serialize(self):
         return self.data
 
     def __repr__(self):
         return "msg_generic()"
 
 
 class msg_getaddr:
     __slots__ = ()
     command = b"getaddr"
 
     def __init__(self):
         pass
 
     def deserialize(self, f):
         pass
 
     def serialize(self):
         return b""
 
     def __repr__(self):
         return "msg_getaddr()"
 
 
 class msg_ping:
     __slots__ = ("nonce",)
     command = b"ping"
 
     def __init__(self, nonce=0):
         self.nonce = nonce
 
     def deserialize(self, f):
         self.nonce = struct.unpack("<Q", f.read(8))[0]
 
     def serialize(self):
         r = b""
         r += struct.pack("<Q", self.nonce)
         return r
 
     def __repr__(self):
         return "msg_ping(nonce={:08x})".format(self.nonce)
 
 
 class msg_pong:
     __slots__ = ("nonce",)
     command = b"pong"
 
     def __init__(self, nonce=0):
         self.nonce = nonce
 
     def deserialize(self, f):
         self.nonce = struct.unpack("<Q", f.read(8))[0]
 
     def serialize(self):
         r = b""
         r += struct.pack("<Q", self.nonce)
         return r
 
     def __repr__(self):
         return "msg_pong(nonce={:08x})".format(self.nonce)
 
 
 class msg_mempool:
     __slots__ = ()
     command = b"mempool"
 
     def __init__(self):
         pass
 
     def deserialize(self, f):
         pass
 
     def serialize(self):
         return b""
 
     def __repr__(self):
         return "msg_mempool()"
 
 
 class msg_notfound:
     __slots__ = ("vec", )
     command = b"notfound"
 
     def __init__(self, vec=None):
         self.vec = vec or []
 
     def deserialize(self, f):
         self.vec = deser_vector(f, CInv)
 
     def serialize(self):
         return ser_vector(self.vec)
 
     def __repr__(self):
         return "msg_notfound(vec={})".format(repr(self.vec))
 
 
 class msg_sendheaders:
     __slots__ = ()
     command = b"sendheaders"
 
     def __init__(self):
         pass
 
     def deserialize(self, f):
         pass
 
     def serialize(self):
         return b""
 
     def __repr__(self):
         return "msg_sendheaders()"
 
 
 # getheaders message has
 # number of entries
 # vector of hashes
 # hash_stop (hash of last desired block header, 0 to get as many as possible)
 class msg_getheaders:
     __slots__ = ("hashstop", "locator",)
     command = b"getheaders"
 
     def __init__(self):
         self.locator = CBlockLocator()
         self.hashstop = 0
 
     def deserialize(self, f):
         self.locator = CBlockLocator()
         self.locator.deserialize(f)
         self.hashstop = deser_uint256(f)
 
     def serialize(self):
         r = b""
         r += self.locator.serialize()
         r += ser_uint256(self.hashstop)
         return r
 
     def __repr__(self):
         return "msg_getheaders(locator={}, stop={:064x})".format(
             repr(self.locator), self.hashstop)
 
 
 # headers message has
 # <count> <vector of block headers>
 class msg_headers:
     __slots__ = ("headers",)
     command = b"headers"
 
     def __init__(self, headers=None):
         self.headers = headers if headers is not None else []
 
     def deserialize(self, f):
         # comment in bitcoind indicates these should be deserialized as blocks
         blocks = deser_vector(f, CBlock)
         for x in blocks:
             self.headers.append(CBlockHeader(x))
 
     def serialize(self):
         blocks = [CBlock(x) for x in self.headers]
         return ser_vector(blocks)
 
     def __repr__(self):
         return "msg_headers(headers={})".format(repr(self.headers))
 
 
 class msg_reject:
     __slots__ = ("code", "data", "message", "reason")
     command = b"reject"
     REJECT_MALFORMED = 1
 
     def __init__(self):
         self.message = b""
         self.code = 0
         self.reason = b""
         self.data = 0
 
     def deserialize(self, f):
         self.message = deser_string(f)
         self.code = struct.unpack("<B", f.read(1))[0]
         self.reason = deser_string(f)
         if (self.code != self.REJECT_MALFORMED
                 and (self.message == b"block" or self.message == b"tx")):
             self.data = deser_uint256(f)
 
     def serialize(self):
         r = ser_string(self.message)
         r += struct.pack("<B", self.code)
         r += ser_string(self.reason)
         if (self.code != self.REJECT_MALFORMED
                 and (self.message == b"block" or self.message == b"tx")):
             r += ser_uint256(self.data)
         return r
 
     def __repr__(self):
         return "msg_reject: {} {} {} [{:064x}]".format(
             self.message, self.code, self.reason, self.data)
 
 
 class msg_merkleblock:
     __slots__ = ("merkleblock",)
     command = b"merkleblock"
 
     def __init__(self, merkleblock=None):
         if merkleblock is None:
             self.merkleblock = CMerkleBlock()
         else:
             self.merkleblock = merkleblock
 
     def deserialize(self, f):
         self.merkleblock.deserialize(f)
 
     def serialize(self):
         return self.merkleblock.serialize()
 
     def __repr__(self):
         return "msg_merkleblock(merkleblock={})".format(repr(self.merkleblock))
 
 
 class msg_filterload:
     __slots__ = ("data", "nHashFuncs", "nTweak", "nFlags")
     command = b"filterload"
 
     def __init__(self, data=b'00', nHashFuncs=0, nTweak=0, nFlags=0):
         self.data = data
         self.nHashFuncs = nHashFuncs
         self.nTweak = nTweak
         self.nFlags = nFlags
 
     def deserialize(self, f):
         self.data = deser_string(f)
         self.nHashFuncs = struct.unpack("<I", f.read(4))[0]
         self.nTweak = struct.unpack("<I", f.read(4))[0]
         self.nFlags = struct.unpack("<B", f.read(1))[0]
 
     def serialize(self):
         r = b""
         r += ser_string(self.data)
         r += struct.pack("<I", self.nHashFuncs)
         r += struct.pack("<I", self.nTweak)
         r += struct.pack("<B", self.nFlags)
         return r
 
     def __repr__(self):
         return "msg_filterload(data={}, nHashFuncs={}, nTweak={}, nFlags={})".format(
             self.data, self.nHashFuncs, self.nTweak, self.nFlags)
 
 
 class msg_filteradd:
     __slots__ = ("data")
     command = b"filteradd"
 
     def __init__(self, data):
         self.data = data
 
     def deserialize(self, f):
         self.data = deser_string(f)
 
     def serialize(self):
         r = b""
         r += ser_string(self.data)
         return r
 
     def __repr__(self):
         return "msg_filteradd(data={})".format(self.data)
 
 
 class msg_filterclear:
     __slots__ = ()
     command = b"filterclear"
 
     def __init__(self):
         pass
 
     def deserialize(self, f):
         pass
 
     def serialize(self):
         return b""
 
     def __repr__(self):
         return "msg_filterclear()"
 
 
 class msg_feefilter:
     __slots__ = ("feerate",)
     command = b"feefilter"
 
     def __init__(self, feerate=0):
         self.feerate = feerate
 
     def deserialize(self, f):
         self.feerate = struct.unpack("<Q", f.read(8))[0]
 
     def serialize(self):
         r = b""
         r += struct.pack("<Q", self.feerate)
         return r
 
     def __repr__(self):
         return "msg_feefilter(feerate={:08x})".format(self.feerate)
 
 
 class msg_sendcmpct:
     __slots__ = ("announce", "version")
     command = b"sendcmpct"
 
     def __init__(self):
         self.announce = False
         self.version = 1
 
     def deserialize(self, f):
         self.announce = struct.unpack("<?", f.read(1))[0]
         self.version = struct.unpack("<Q", f.read(8))[0]
 
     def serialize(self):
         r = b""
         r += struct.pack("<?", self.announce)
         r += struct.pack("<Q", self.version)
         return r
 
     def __repr__(self):
         return "msg_sendcmpct(announce={}, version={})".format(
             self.announce, self.version)
 
 
 class msg_cmpctblock:
     __slots__ = ("header_and_shortids",)
     command = b"cmpctblock"
 
     def __init__(self, header_and_shortids=None):
         self.header_and_shortids = header_and_shortids
 
     def deserialize(self, f):
         self.header_and_shortids = P2PHeaderAndShortIDs()
         self.header_and_shortids.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.header_and_shortids.serialize()
         return r
 
     def __repr__(self):
         return "msg_cmpctblock(HeaderAndShortIDs={})".format(
             repr(self.header_and_shortids))
 
 
 class msg_getblocktxn:
     __slots__ = ("block_txn_request",)
     command = b"getblocktxn"
 
     def __init__(self):
         self.block_txn_request = None
 
     def deserialize(self, f):
         self.block_txn_request = BlockTransactionsRequest()
         self.block_txn_request.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.block_txn_request.serialize()
         return r
 
     def __repr__(self):
         return "msg_getblocktxn(block_txn_request={})".format(
             repr(self.block_txn_request))
 
 
 class msg_blocktxn:
     __slots__ = ("block_transactions",)
     command = b"blocktxn"
 
     def __init__(self):
         self.block_transactions = BlockTransactions()
 
     def deserialize(self, f):
         self.block_transactions.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.block_transactions.serialize()
         return r
 
     def __repr__(self):
         return "msg_blocktxn(block_transactions={})".format(
             repr(self.block_transactions))
 
 
 class msg_avapoll():
     __slots__ = ("poll",)
     command = b"avapoll"
 
     def __init__(self):
         self.poll = AvalanchePoll()
 
     def deserialize(self, f):
         self.poll.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.poll.serialize()
         return r
 
     def __repr__(self):
         return "msg_avapoll(poll={})".format(repr(self.poll))
 
 
 class msg_avaresponse():
     __slots__ = ("response",)
     command = b"avaresponse"
 
     def __init__(self):
         self.response = AvalancheResponse()
 
     def deserialize(self, f):
         self.response.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.response.serialize()
         return r
 
     def __repr__(self):
         return "msg_avaresponse(response={})".format(repr(self.response))
 
 
 class msg_tcpavaresponse():
     __slots__ = ("response",)
     command = b"avaresponse"
 
     def __init__(self):
         self.response = TCPAvalancheResponse()
 
     def deserialize(self, f):
         self.response.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.response.serialize()
         return r
 
     def __repr__(self):
         return "msg_tcpavaresponse(response={})".format(repr(self.response))