diff --git a/qa/rpc-tests/test_framework/mininode.py b/qa/rpc-tests/test_framework/mininode.py
index ff18344702..1e74358301 100755
--- a/qa/rpc-tests/test_framework/mininode.py
+++ b/qa/rpc-tests/test_framework/mininode.py
@@ -1,1807 +1,1817 @@
 #!/usr/bin/env python3
 # Copyright (c) 2010 ArtForz -- public domain half-a-node
 # Copyright (c) 2012 Jeff Garzik
 # Copyright (c) 2010-2016 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #
 # mininode.py - Bitcoin P2P network half-a-node
 #
 # This python code was modified from ArtForz' public domain  half-a-node, as
 # found in the mini-node branch of http://github.com/jgarzik/pynode.
 #
 # NodeConn: an object which manages p2p connectivity to a bitcoin node
 # NodeConnCB: a base class that describes the interface for receiving
 #             callbacks with network messages from a NodeConn
 # 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
 
 
 import struct
 import socket
 import asyncore
 import time
 import sys
 import random
 from .util import hex_str_to_bytes, bytes_to_hex_str
 from io import BytesIO
 from codecs import encode
 import hashlib
 from threading import RLock
 from threading import Thread
 import logging
 import copy
 from test_framework.siphash import siphash256
 from test_framework.cdefs import MAX_BLOCK_SIGOPS_PER_MB
 
 BIP0031_VERSION = 60000
 MY_VERSION = 70014  # past bip-31 for ping/pong
 MY_SUBVERSION = b"/python-mininode-tester:0.0.3/"
 MY_RELAY = 1 # from version 70001 onwards, fRelay should be appended to version messages (BIP37)
 
 MAX_INV_SZ = 50000
 
 COIN = 100000000 # 1 btc in satoshis
 
 NODE_NETWORK = (1 << 0)
 NODE_GETUTXO = (1 << 1)
 NODE_BLOOM = (1 << 2)
 NODE_WITNESS = (1 << 3)
 
+# Howmuch data will be read from the network at once
+READ_BUFFER_SIZE = 8192
+
 # Keep our own socket map for asyncore, so that we can track disconnects
 # ourselves (to workaround an issue with closing an asyncore socket when
 # using select)
 mininode_socket_map = dict()
 
 # One lock for synchronizing all data access between the networking thread (see
 # NetworkThread below) and the thread running the test logic.  For simplicity,
 # NodeConn acquires this lock whenever delivering a message to to a NodeConnCB,
 # and whenever adding anything to the send buffer (in send_message()).  This
 # lock should be acquired in the thread running the test logic to synchronize
 # access to any data shared with the NodeConnCB or NodeConn.
 mininode_lock = RLock()
 
 # 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(l):
     r = b""
     if l < 253:
         r = struct.pack("B", l)
     elif l < 0x10000:
         r = struct.pack("<BH", 253, l)
     elif l < 0x100000000:
         r = struct.pack("<BI", 254, l)
     else:
         r = struct.pack("<BQ", 255, l)
     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 (we use this for serializing the vector of transactions
 # for a witness block).
 def ser_vector(l, ser_function_name=None):
     r = ser_compact_size(len(l))
     for i in l:
         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(l):
     r = ser_compact_size(len(l))
     for i in l:
         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(l):
     r = ser_compact_size(len(l))
     for sv in l:
         r += ser_string(sv)
     return r
 
 
 def deser_int_vector(f):
     nit = deser_compact_size(f)
     r = []
     for i in range(nit):
         t = struct.unpack("<i", f.read(4))[0]
         r.append(t)
     return r
 
 
 def ser_int_vector(l):
     r = ser_compact_size(len(l))
     for i in l:
         r += struct.pack("<i", i)
     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 bytes_to_hex_str(obj.serialize())
 
 # Objects that map to bitcoind objects, which can be serialized/deserialized
 
 class CAddress(object):
     def __init__(self):
         self.nServices = 1
         self.pchReserved = b"\x00" * 10 + b"\xff" * 2
         self.ip = "0.0.0.0"
         self.port = 0
 
     def deserialize(self, f):
         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):
         r = b""
         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=%i ip=%s port=%i)" % (self.nServices,
                                                          self.ip, self.port)
 
 MSG_WITNESS_FLAG = 1<<30
 
 class CInv(object):
     typemap = {
         0: "Error",
         1: "TX",
         2: "Block",
         1|MSG_WITNESS_FLAG: "WitnessTx",
         2|MSG_WITNESS_FLAG : "WitnessBlock",
         4: "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=%s hash=%064x)" \
             % (self.typemap[self.type], self.hash)
 
 
 class CBlockLocator(object):
     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=%i vHave=%s)" \
             % (self.nVersion, repr(self.vHave))
 
 
 class COutPoint(object):
     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=%i)" % (self.hash, self.n)
 
 
 class CTxIn(object):
     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=%s scriptSig=%s nSequence=%i)" \
             % (repr(self.prevout), bytes_to_hex_str(self.scriptSig),
                self.nSequence)
 
 
 class CTxOut(object):
     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=%i.%08i scriptPubKey=%s)" \
             % (self.nValue // COIN, self.nValue % COIN,
                bytes_to_hex_str(self.scriptPubKey))
 
 
 class CScriptWitness(object):
     def __init__(self):
         # stack is a vector of strings
         self.stack = []
 
     def __repr__(self):
         return "CScriptWitness(%s)" % \
                (",".join([bytes_to_hex_str(x) for x in self.stack]))
 
     def is_null(self):
         if self.stack:
             return False
         return True
 
 
 class CTxInWitness(object):
     def __init__(self):
         self.scriptWitness = CScriptWitness()
 
     def deserialize(self, f):
         self.scriptWitness.stack = deser_string_vector(f)
 
     def serialize(self):
         return ser_string_vector(self.scriptWitness.stack)
 
     def __repr__(self):
         return repr(self.scriptWitness)
 
     def is_null(self):
         return self.scriptWitness.is_null()
 
 
 class CTxWitness(object):
     def __init__(self):
         self.vtxinwit = []
 
     def deserialize(self, f):
         for i in range(len(self.vtxinwit)):
             self.vtxinwit[i].deserialize(f)
 
     def serialize(self):
         r = b""
         # This is different than the usual vector serialization --
         # we omit the length of the vector, which is required to be
         # the same length as the transaction's vin vector.
         for x in self.vtxinwit:
             r += x.serialize()
         return r
 
     def __repr__(self):
         return "CTxWitness(%s)" % \
                (';'.join([repr(x) for x in self.vtxinwit]))
 
     def is_null(self):
         for x in self.vtxinwit:
             if not x.is_null():
                 return False
         return True
 
 
 class CTransaction(object):
     def __init__(self, tx=None):
         if tx is None:
             self.nVersion = 1
             self.vin = []
             self.vout = []
             self.wit = CTxWitness()
             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
             self.wit = copy.deepcopy(tx.wit)
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
         self.vin = deser_vector(f, CTxIn)
         flags = 0
         if len(self.vin) == 0:
             flags = struct.unpack("<B", f.read(1))[0]
             # Not sure why flags can't be zero, but this
             # matches the implementation in bitcoind
             if (flags != 0):
                 self.vin = deser_vector(f, CTxIn)
                 self.vout = deser_vector(f, CTxOut)
         else:
             self.vout = deser_vector(f, CTxOut)
         if flags != 0:
             self.wit.vtxinwit = [CTxInWitness() for i in range(len(self.vin))]
             self.wit.deserialize(f)
         self.nLockTime = struct.unpack("<I", f.read(4))[0]
         self.sha256 = None
         self.hash = None
 
     def serialize_without_witness(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
 
     # Only serialize with witness when explicitly called for
     def serialize_with_witness(self):
         flags = 0
         if not self.wit.is_null():
             flags |= 1
         r = b""
         r += struct.pack("<i", self.nVersion)
         if flags:
             dummy = []
             r += ser_vector(dummy)
             r += struct.pack("<B", flags)
         r += ser_vector(self.vin)
         r += ser_vector(self.vout)
         if flags & 1:
             if (len(self.wit.vtxinwit) != len(self.vin)):
                 # vtxinwit must have the same length as vin
                 self.wit.vtxinwit = self.wit.vtxinwit[:len(self.vin)]
                 for i in range(len(self.wit.vtxinwit), len(self.vin)):
                     self.wit.vtxinwit.append(CTxInWitness())
             r += self.wit.serialize()
         r += struct.pack("<I", self.nLockTime)
         return r
 
     # Regular serialization is without witness -- must explicitly
     # call serialize_with_witness to include witness data.
     def serialize(self):
         return self.serialize_without_witness()
 
     # Recalculate the txid (transaction hash without witness)
     def rehash(self):
         self.sha256 = None
         self.calc_sha256()
 
     # We will only cache the serialization without witness in
     # self.sha256 and self.hash -- those are expected to be the txid.
     def calc_sha256(self, with_witness=False):
         if with_witness:
             # Don't cache the result, just return it
             return uint256_from_str(hash256(self.serialize_with_witness()))
 
         if self.sha256 is None:
             self.sha256 = uint256_from_str(hash256(self.serialize_without_witness()))
         self.hash = encode(hash256(self.serialize())[::-1], 'hex_codec').decode('ascii')
 
     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=%i vin=%s vout=%s wit=%s nLockTime=%i)" \
             % (self.nVersion, repr(self.vin), repr(self.vout), repr(self.wit), self.nLockTime)
 
 
 class CBlockHeader(object):
     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=%i hashPrevBlock=%064x hashMerkleRoot=%064x nTime=%s nBits=%08x nNonce=%08x)" \
             % (self.nVersion, self.hashPrevBlock, self.hashMerkleRoot,
                time.ctime(self.nTime), self.nBits, self.nNonce)
 
 
 class CBlock(CBlockHeader):
     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, with_witness=False):
         r = b""
         r += super(CBlock, self).serialize()
         if with_witness:
             r += ser_vector(self.vtx, "serialize_with_witness")
         else:
             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 calc_witness_merkle_root(self):
         # For witness root purposes, the hash of the
         # coinbase, with witness, is defined to be 0...0
         hashes = [ser_uint256(0)]
 
         for tx in self.vtx[1:]:
             # Calculate the hashes with witness data
             hashes.append(ser_uint256(tx.calc_sha256(True)))
 
         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=%i hashPrevBlock=%064x hashMerkleRoot=%064x nTime=%s nBits=%08x nNonce=%08x vtx=%s)" \
             % (self.nVersion, self.hashPrevBlock, self.hashMerkleRoot,
                time.ctime(self.nTime), self.nBits, self.nNonce, repr(self.vtx))
 
 
 class CUnsignedAlert(object):
     def __init__(self):
         self.nVersion = 1
         self.nRelayUntil = 0
         self.nExpiration = 0
         self.nID = 0
         self.nCancel = 0
         self.setCancel = []
         self.nMinVer = 0
         self.nMaxVer = 0
         self.setSubVer = []
         self.nPriority = 0
         self.strComment = b""
         self.strStatusBar = b""
         self.strReserved = b""
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
         self.nRelayUntil = struct.unpack("<q", f.read(8))[0]
         self.nExpiration = struct.unpack("<q", f.read(8))[0]
         self.nID = struct.unpack("<i", f.read(4))[0]
         self.nCancel = struct.unpack("<i", f.read(4))[0]
         self.setCancel = deser_int_vector(f)
         self.nMinVer = struct.unpack("<i", f.read(4))[0]
         self.nMaxVer = struct.unpack("<i", f.read(4))[0]
         self.setSubVer = deser_string_vector(f)
         self.nPriority = struct.unpack("<i", f.read(4))[0]
         self.strComment = deser_string(f)
         self.strStatusBar = deser_string(f)
         self.strReserved = deser_string(f)
 
     def serialize(self):
         r = b""
         r += struct.pack("<i", self.nVersion)
         r += struct.pack("<q", self.nRelayUntil)
         r += struct.pack("<q", self.nExpiration)
         r += struct.pack("<i", self.nID)
         r += struct.pack("<i", self.nCancel)
         r += ser_int_vector(self.setCancel)
         r += struct.pack("<i", self.nMinVer)
         r += struct.pack("<i", self.nMaxVer)
         r += ser_string_vector(self.setSubVer)
         r += struct.pack("<i", self.nPriority)
         r += ser_string(self.strComment)
         r += ser_string(self.strStatusBar)
         r += ser_string(self.strReserved)
         return r
 
     def __repr__(self):
         return "CUnsignedAlert(nVersion %d, nRelayUntil %d, nExpiration %d, nID %d, nCancel %d, nMinVer %d, nMaxVer %d, nPriority %d, strComment %s, strStatusBar %s, strReserved %s)" \
             % (self.nVersion, self.nRelayUntil, self.nExpiration, self.nID,
                self.nCancel, self.nMinVer, self.nMaxVer, self.nPriority,
                self.strComment, self.strStatusBar, self.strReserved)
 
 
 class CAlert(object):
     def __init__(self):
         self.vchMsg = b""
         self.vchSig = b""
 
     def deserialize(self, f):
         self.vchMsg = deser_string(f)
         self.vchSig = deser_string(f)
 
     def serialize(self):
         r = b""
         r += ser_string(self.vchMsg)
         r += ser_string(self.vchSig)
         return r
 
     def __repr__(self):
         return "CAlert(vchMsg.sz %d, vchSig.sz %d)" \
             % (len(self.vchMsg), len(self.vchSig))
 
 
 class PrefilledTransaction(object):
     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, with_witness=False):
         r = b""
         r += ser_compact_size(self.index)
         if with_witness:
             r += self.tx.serialize_with_witness()
         else:
             r += self.tx.serialize_without_witness()
         return r
 
     def serialize_with_witness(self):
         return self.serialize(with_witness=True)
 
     def __repr__(self):
         return "PrefilledTransaction(index=%d, tx=%s)" % (self.index, repr(self.tx))
 
 # This is what we send on the wire, in a cmpctblock message.
 class P2PHeaderAndShortIDs(object):
     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)
 
     # When using version 2 compact blocks, we must serialize with_witness.
     def serialize(self, with_witness=False):
         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]
         if with_witness:
             r += ser_vector(self.prefilled_txn, "serialize_with_witness")
         else:
             r += ser_vector(self.prefilled_txn)
         return r
 
     def __repr__(self):
         return "P2PHeaderAndShortIDs(header=%s, nonce=%d, shortids_length=%d, shortids=%s, prefilled_txn_length=%d, prefilledtxn=%s" % (repr(self.header), self.nonce, self.shortids_length, repr(self.shortids), self.prefilled_txn_length, repr(self.prefilled_txn))
 
 # P2P version of the above that will use witness serialization (for compact
 # block version 2)
 class P2PHeaderAndShortWitnessIDs(P2PHeaderAndShortIDs):
     def serialize(self):
         return super(P2PHeaderAndShortWitnessIDs, self).serialize(with_witness=True)
 
 # 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(object):
     def __init__(self, p2pheaders_and_shortids = None):
         self.header = CBlockHeader()
         self.nonce = 0
         self.shortids = []
         self.prefilled_txn = []
         self.use_witness = False
 
         if p2pheaders_and_shortids != 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):
         if self.use_witness:
             ret = P2PHeaderAndShortWitnessIDs()
         else:
             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], use_witness = False):
         self.header = CBlockHeader(block)
         self.nonce = nonce
         self.prefilled_txn = [ PrefilledTransaction(i, block.vtx[i]) for i in prefill_list ]
         self.shortids = []
         self.use_witness = use_witness
         [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
                 if use_witness:
                     tx_hash = block.vtx[i].calc_sha256(with_witness=True)
                 self.shortids.append(calculate_shortid(k0, k1, tx_hash))
 
     def __repr__(self):
         return "HeaderAndShortIDs(header=%s, nonce=%d, shortids=%s, prefilledtxn=%s" % (repr(self.header), self.nonce, repr(self.shortids), repr(self.prefilled_txn))
 
 
 class BlockTransactionsRequest(object):
 
     def __init__(self, blockhash=0, indexes = None):
         self.blockhash = blockhash
         self.indexes = indexes if indexes != 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=%s)" % (self.blockhash, repr(self.indexes))
 
 
 class BlockTransactions(object):
 
     def __init__(self, blockhash=0, transactions = None):
         self.blockhash = blockhash
         self.transactions = transactions if transactions != None else []
 
     def deserialize(self, f):
         self.blockhash = deser_uint256(f)
         self.transactions = deser_vector(f, CTransaction)
 
     def serialize(self, with_witness=False):
         r = b""
         r += ser_uint256(self.blockhash)
         if with_witness:
             r += ser_vector(self.transactions, "serialize_with_witness")
         else:
             r += ser_vector(self.transactions)
         return r
 
     def __repr__(self):
         return "BlockTransactions(hash=%064x transactions=%s)" % (self.blockhash, repr(self.transactions))
 
 
 # Objects that correspond to messages on the wire
 class msg_version(object):
     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]
         if self.nVersion == 10300:
             self.nVersion = 300
         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)
 
         if self.nVersion >= 106:
             self.addrFrom = CAddress()
             self.addrFrom.deserialize(f)
             self.nNonce = struct.unpack("<Q", f.read(8))[0]
             self.strSubVer = deser_string(f)
         else:
             self.addrFrom = None
             self.nNonce = None
             self.strSubVer = None
             self.nStartingHeight = None
 
         if self.nVersion >= 209:
             self.nStartingHeight = struct.unpack("<i", f.read(4))[0]
         else:
             self.nStartingHeight = None
 
         if self.nVersion >= 70001:
             # Relay field is optional for version 70001 onwards
             try:
                 self.nRelay = struct.unpack("<b", f.read(1))[0]
             except:
                 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()
         r += self.addrFrom.serialize()
         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=%i nServices=%i nTime=%s addrTo=%s addrFrom=%s nNonce=0x%016X strSubVer=%s nStartingHeight=%i nRelay=%i)' \
             % (self.nVersion, self.nServices, time.ctime(self.nTime),
                repr(self.addrTo), repr(self.addrFrom), self.nNonce,
                self.strSubVer, self.nStartingHeight, self.nRelay)
 
 
 class msg_verack(object):
     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(object):
     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=%s)" % (repr(self.addrs))
 
 
 class msg_alert(object):
     command = b"alert"
 
     def __init__(self):
         self.alert = CAlert()
 
     def deserialize(self, f):
         self.alert = CAlert()
         self.alert.deserialize(f)
 
     def serialize(self):
         r = b""
         r += self.alert.serialize()
         return r
 
     def __repr__(self):
         return "msg_alert(alert=%s)" % (repr(self.alert), )
 
 
 class msg_inv(object):
     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=%s)" % (repr(self.inv))
 
 
 class msg_getdata(object):
     command = b"getdata"
 
     def __init__(self, inv=None):
         self.inv = inv if inv != 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=%s)" % (repr(self.inv))
 
 
 class msg_getblocks(object):
     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=%s hashstop=%064x)" \
             % (repr(self.locator), self.hashstop)
 
 
 class msg_tx(object):
     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_without_witness()
 
     def __repr__(self):
         return "msg_tx(tx=%s)" % (repr(self.tx))
 
 class msg_witness_tx(msg_tx):
 
     def serialize(self):
         return self.tx.serialize_with_witness()
 
 
 class msg_block(object):
     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=%s)" % (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(object):
     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_witness_block(msg_block):
 
     def serialize(self):
         r = self.block.serialize(with_witness=True)
         return r
 
 class msg_getaddr(object):
     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_prebip31(object):
     command = b"ping"
 
     def __init__(self):
         pass
 
     def deserialize(self, f):
         pass
 
     def serialize(self):
         return b""
 
     def __repr__(self):
         return "msg_ping() (pre-bip31)"
 
 
 class msg_ping(object):
     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)" % self.nonce
 
 
 class msg_pong(object):
     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)" % self.nonce
 
 
 class msg_mempool(object):
     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_sendheaders(object):
     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(object):
     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=%s, stop=%064x)" \
             % (repr(self.locator), self.hashstop)
 
 
 # headers message has
 # <count> <vector of block headers>
 class msg_headers(object):
     command = b"headers"
 
     def __init__(self):
         self.headers = []
 
     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=%s)" % repr(self.headers)
 
 
 class msg_reject(object):
     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: %s %d %s [%064x]" \
             % (self.message, self.code, self.reason, self.data)
 
 # Helper function
 def wait_until(predicate, *, attempts=float('inf'), timeout=float('inf')):
     attempt = 0
     elapsed = 0
 
     while attempt < attempts and elapsed < timeout:
         with mininode_lock:
             if predicate():
                 return True
         attempt += 1
         elapsed += 0.05
         time.sleep(0.05)
 
     return False
 
 class msg_feefilter(object):
     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)" % self.feerate
 
 class msg_sendcmpct(object):
     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=%s, version=%lu)" % (self.announce, self.version)
 
 class msg_cmpctblock(object):
     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=%s)" % repr(self.header_and_shortids)
 
 class msg_getblocktxn(object):
     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=%s)" % (repr(self.block_txn_request))
 
 class msg_blocktxn(object):
     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=%s)" % (repr(self.block_transactions))
 
 class msg_witness_blocktxn(msg_blocktxn):
     def serialize(self):
         r = b""
         r += self.block_transactions.serialize(with_witness=True)
         return r
 
 # This is what a callback should look like for NodeConn
 # Reimplement the on_* functions to provide handling for events
 class NodeConnCB(object):
     def __init__(self):
         self.verack_received = False
         # deliver_sleep_time is helpful for debugging race conditions in p2p
         # tests; it causes message delivery to sleep for the specified time
         # before acquiring the global lock and delivering the next message.
         self.deliver_sleep_time = None
         # Remember the services our peer has advertised
         self.peer_services = None
 
     def set_deliver_sleep_time(self, value):
         with mininode_lock:
             self.deliver_sleep_time = value
 
     def get_deliver_sleep_time(self):
         with mininode_lock:
             return self.deliver_sleep_time
 
     # Spin until verack message is received from the node.
     # Tests may want to use this as a signal that the test can begin.
     # This can be called from the testing thread, so it needs to acquire the
     # global lock.
     def wait_for_verack(self):
         while True:
             with mininode_lock:
                 if self.verack_received:
                     return
             time.sleep(0.05)
 
     def deliver(self, conn, message):
         deliver_sleep = self.get_deliver_sleep_time()
         if deliver_sleep is not None:
             time.sleep(deliver_sleep)
         with mininode_lock:
             try:
                 getattr(self, 'on_' + message.command.decode('ascii'))(conn, message)
             except:
                 print("ERROR delivering %s (%s)" % (repr(message),
                                                     sys.exc_info()[0]))
 
     def on_version(self, conn, message):
         if message.nVersion >= 209:
             conn.send_message(msg_verack())
         conn.ver_send = min(MY_VERSION, message.nVersion)
         if message.nVersion < 209:
             conn.ver_recv = conn.ver_send
         conn.nServices = message.nServices
 
     def on_verack(self, conn, message):
         conn.ver_recv = conn.ver_send
         self.verack_received = True
 
     def on_inv(self, conn, message):
         want = msg_getdata()
         for i in message.inv:
             if i.type != 0:
                 want.inv.append(i)
         if len(want.inv):
             conn.send_message(want)
 
     def on_addr(self, conn, message): pass
     def on_alert(self, conn, message): pass
     def on_getdata(self, conn, message): pass
     def on_getblocks(self, conn, message): pass
     def on_tx(self, conn, message): pass
     def on_block(self, conn, message): pass
     def on_getaddr(self, conn, message): pass
     def on_headers(self, conn, message): pass
     def on_getheaders(self, conn, message): pass
     def on_ping(self, conn, message):
         if conn.ver_send > BIP0031_VERSION:
             conn.send_message(msg_pong(message.nonce))
     def on_reject(self, conn, message): pass
     def on_open(self, conn): pass
     def on_close(self, conn): pass
     def on_mempool(self, conn): pass
     def on_pong(self, conn, message): pass
     def on_feefilter(self, conn, message): pass
     def on_sendheaders(self, conn, message): pass
     def on_sendcmpct(self, conn, message): pass
     def on_cmpctblock(self, conn, message): pass
     def on_getblocktxn(self, conn, message): pass
     def on_blocktxn(self, conn, message): pass
 
 # More useful callbacks and functions for NodeConnCB's which have a single NodeConn
 class SingleNodeConnCB(NodeConnCB):
     def __init__(self):
         NodeConnCB.__init__(self)
         self.connection = None
         self.ping_counter = 1
         self.last_pong = msg_pong()
 
     def add_connection(self, conn):
         self.connection = conn
 
     # Wrapper for the NodeConn's send_message function
     def send_message(self, message):
         self.connection.send_message(message)
 
     def send_and_ping(self, message):
         self.send_message(message)
         self.sync_with_ping()
 
     def on_pong(self, conn, message):
         self.last_pong = message
 
     # Sync up with the node
     def sync_with_ping(self, timeout=30):
         def received_pong():
             return (self.last_pong.nonce == self.ping_counter)
         self.send_message(msg_ping(nonce=self.ping_counter))
         success = wait_until(received_pong, timeout=timeout)
         self.ping_counter += 1
         return success
 
 # The actual NodeConn class
 # This class provides an interface for a p2p connection to a specified node
 class NodeConn(asyncore.dispatcher):
     messagemap = {
         b"version": msg_version,
         b"verack": msg_verack,
         b"addr": msg_addr,
         b"alert": msg_alert,
         b"inv": msg_inv,
         b"getdata": msg_getdata,
         b"getblocks": msg_getblocks,
         b"tx": msg_tx,
         b"block": msg_block,
         b"getaddr": msg_getaddr,
         b"ping": msg_ping,
         b"pong": msg_pong,
         b"headers": msg_headers,
         b"getheaders": msg_getheaders,
         b"reject": msg_reject,
         b"mempool": msg_mempool,
         b"feefilter": msg_feefilter,
         b"sendheaders": msg_sendheaders,
         b"sendcmpct": msg_sendcmpct,
         b"cmpctblock": msg_cmpctblock,
         b"getblocktxn": msg_getblocktxn,
         b"blocktxn": msg_blocktxn
     }
+
     MAGIC_BYTES = {
         "mainnet": b"\xf9\xbe\xb4\xd9",   # mainnet
         "testnet3": b"\x0b\x11\x09\x07",  # testnet3
         "regtest": b"\xfa\xbf\xb5\xda",   # regtest
     }
 
     def __init__(self, dstaddr, dstport, rpc, callback, net="regtest", services=NODE_NETWORK, send_version=True):
         asyncore.dispatcher.__init__(self, map=mininode_socket_map)
         self.log = logging.getLogger("NodeConn(%s:%d)" % (dstaddr, dstport))
         self.dstaddr = dstaddr
         self.dstport = dstport
         self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
         self.sendbuf = b""
         self.recvbuf = b""
         self.ver_send = 209
         self.ver_recv = 209
         self.last_sent = 0
         self.state = "connecting"
         self.network = net
         self.cb = callback
         self.disconnect = False
         self.nServices = 0
 
         if send_version:
             # stuff version msg into sendbuf
             vt = msg_version()
             vt.nServices = services
             vt.addrTo.ip = self.dstaddr
             vt.addrTo.port = self.dstport
             vt.addrFrom.ip = "0.0.0.0"
             vt.addrFrom.port = 0
             self.send_message(vt, True)
 
         print('MiniNode: Connecting to Bitcoin Node IP # ' + dstaddr + ':' \
             + str(dstport))
 
         try:
             self.connect((dstaddr, dstport))
         except:
             self.handle_close()
         self.rpc = rpc
 
     def show_debug_msg(self, msg):
         self.log.debug(msg)
 
     def handle_connect(self):
         if self.state != "connected":
             self.show_debug_msg("MiniNode: Connected & Listening: \n")
             self.state = "connected"
             self.cb.on_open(self)
 
     def handle_close(self):
         self.show_debug_msg("MiniNode: Closing Connection to %s:%d... "
                             % (self.dstaddr, self.dstport))
         self.state = "closed"
         self.recvbuf = b""
         self.sendbuf = b""
         try:
             self.close()
         except:
             pass
         self.cb.on_close(self)
 
     def handle_read(self):
         try:
-            t = self.recv(8192)
-            if len(t) > 0:
-                self.recvbuf += t
-                self.got_data()
+            with mininode_lock:
+                t = self.recv(READ_BUFFER_SIZE)
+                if len(t) > 0:
+                    self.recvbuf += t
         except:
             pass
 
+        while True:
+            msg = self.got_data()
+            if msg == None:
+                break
+            self.got_message(msg)
+
     def readable(self):
         return True
 
     def writable(self):
         with mininode_lock:
             pre_connection = self.state == "connecting"
             length = len(self.sendbuf)
         return (length > 0 or pre_connection)
 
     def handle_write(self):
         with mininode_lock:
             # asyncore does not expose socket connection, only the first read/write
             # event, thus we must check connection manually here to know when we
             # actually connect
             if self.state == "connecting":
                 self.handle_connect()
             if not self.writable():
                 return
 
             try:
                 sent = self.send(self.sendbuf)
             except:
                 self.handle_close()
                 return
             self.sendbuf = self.sendbuf[sent:]
 
     def got_data(self):
         try:
-            while True:
+            with mininode_lock:
                 if len(self.recvbuf) < 4:
-                    return
+                    return None
                 if self.recvbuf[:4] != self.MAGIC_BYTES[self.network]:
                     raise ValueError("got garbage %s" % repr(self.recvbuf))
                 if self.ver_recv < 209:
                     if len(self.recvbuf) < 4 + 12 + 4:
-                        return
+                        return None
                     command = self.recvbuf[4:4+12].split(b"\x00", 1)[0]
                     msglen = struct.unpack("<i", self.recvbuf[4+12:4+12+4])[0]
                     checksum = None
                     if len(self.recvbuf) < 4 + 12 + 4 + msglen:
-                        return
+                        return None
                     msg = self.recvbuf[4+12+4:4+12+4+msglen]
                     self.recvbuf = self.recvbuf[4+12+4+msglen:]
                 else:
                     if len(self.recvbuf) < 4 + 12 + 4 + 4:
-                        return
+                        return None
                     command = self.recvbuf[4:4+12].split(b"\x00", 1)[0]
                     msglen = struct.unpack("<i", self.recvbuf[4+12:4+12+4])[0]
                     checksum = self.recvbuf[4+12+4:4+12+4+4]
                     if len(self.recvbuf) < 4 + 12 + 4 + 4 + msglen:
-                        return
+                        return None
                     msg = self.recvbuf[4+12+4+4:4+12+4+4+msglen]
-                    th = sha256(msg)
-                    h = sha256(th)
+                    h = sha256(sha256(msg))
                     if checksum != h[:4]:
                         raise ValueError("got bad checksum " + repr(self.recvbuf))
                     self.recvbuf = self.recvbuf[4+12+4+4+msglen:]
-                if command in self.messagemap:
-                    f = BytesIO(msg)
-                    t = self.messagemap[command]()
-                    t.deserialize(f)
-                    self.got_message(t)
-                else:
+                if command not in self.messagemap:
                     self.show_debug_msg("Unknown command: '" + command + "' " +
                                         repr(msg))
+                    return None
+                f = BytesIO(msg)
+                m = self.messagemap[command]()
+                m.deserialize(f)
+                return m
+
         except Exception as e:
             print('got_data:', repr(e))
             # import  traceback
             # traceback.print_tb(sys.exc_info()[2])
 
     def send_message(self, message, pushbuf=False):
         if self.state != "connected" and not pushbuf:
             raise IOError('Not connected, no pushbuf')
         self.show_debug_msg("Send %s" % repr(message))
         command = message.command
         data = message.serialize()
         tmsg = self.MAGIC_BYTES[self.network]
         tmsg += command
         tmsg += b"\x00" * (12 - len(command))
         tmsg += struct.pack("<I", len(data))
         if self.ver_send >= 209:
             th = sha256(data)
             h = sha256(th)
             tmsg += h[:4]
         tmsg += data
         with mininode_lock:
             self.sendbuf += tmsg
             self.last_sent = time.time()
 
     def got_message(self, message):
         if message.command == b"version":
             if message.nVersion <= BIP0031_VERSION:
                 self.messagemap[b'ping'] = msg_ping_prebip31
         if self.last_sent + 30 * 60 < time.time():
             self.send_message(self.messagemap[b'ping']())
         self.show_debug_msg("Recv %s" % repr(message))
         self.cb.deliver(self, message)
 
     def disconnect_node(self):
         self.disconnect = True
 
 
 class NetworkThread(Thread):
     def run(self):
         while mininode_socket_map:
             # We check for whether to disconnect outside of the asyncore
             # loop to workaround the behavior of asyncore when using
             # select
             disconnected = []
             for fd, obj in mininode_socket_map.items():
                 if obj.disconnect:
                     disconnected.append(obj)
             [ obj.handle_close() for obj in disconnected ]
             asyncore.loop(0.1, use_poll=True, map=mininode_socket_map, count=1)
 
 
 # An exception we can raise if we detect a potential disconnect
 # (p2p or rpc) before the test is complete
 class EarlyDisconnectError(Exception):
     def __init__(self, value):
         self.value = value
 
     def __str__(self):
         return repr(self.value)