Start on network.

basicswap/basicswap.py

@@ -10,11 +10,12 @@ import zmq
 import json
 import time
 import base64
-import shutil
 import random
+import shutil
+import struct
+import hashlib
 import logging
 import secrets
-import hashlib
 import datetime as dt
 import traceback
 import sqlalchemy as sa
@@ -387,8 +388,9 @@ def replaceAddrPrefix(addr, coin_type, chain_name, addr_type='pubkey_address'):
     return encodeAddress(bytes((chainparams[coin_type][chain_name][addr_type],)) + decodeAddress(addr)[1:])
 
 
-class WatchedOutput():
-    # Watch for spends
+class WatchedOutput():  # Watch for spends
+    __slots__ = ('bid_id', 'txid_hex', 'vout', 'tx_type', 'swap_type')
+
     def __init__(self, bid_id, txid_hex, vout, tx_type, swap_type):
         self.bid_id = bid_id
         self.txid_hex = txid_hex
@@ -398,6 +400,7 @@ class WatchedOutput():
 
 
 class WatchedTransaction():
+    # TODO
     # Watch for presence in mempool (getrawtransaction)
     def __init__(self, bid_id, txid_hex, tx_type, swap_type):
         self.bid_id = bid_id
@@ -410,6 +413,9 @@ class BasicSwap(BaseApp):
     def __init__(self, fp, data_dir, settings, chain, log_name='BasicSwap'):
         super().__init__(fp, data_dir, settings, chain, log_name)
 
+        v = __version__.split('.')
+        self._version = struct.pack('>HHH', int(v[0]), int(v[1]), int(v[2]))
+
         self.check_progress_seconds = self.settings.get('check_progress_seconds', 60)
         self.check_watched_seconds = self.settings.get('check_watched_seconds', 60)
         self.check_expired_seconds = self.settings.get('check_expired_seconds', 60 * 5)
@@ -509,10 +515,14 @@ class BasicSwap(BaseApp):
         random.seed(secrets.randbits(128))
 
     def finalise(self):
+        self.log.info('Finalise')
+
+        with self.mxDB:
+            self.is_running = False
+
         if self._network:
             self._network.stopNetwork()
             self._network = None
-        self.log.info('Finalise')
 
     def setCoinConnectParams(self, coin):
         # Set anything that does not require the daemon to be running
@@ -662,7 +672,7 @@ class BasicSwap(BaseApp):
 
         if 'p2p_host' in self.settings:
             network_key = self.getNetworkKey(1)
-            self._network = bsn.Network(self.settings['p2p_host'], self.settings['p2p_port'], network_key)
+            self._network = bsn.Network(self.settings['p2p_host'], self.settings['p2p_port'], network_key, self)
             self._network.startNetwork()
 
         self.initialise()
@@ -4740,3 +4750,7 @@ class BasicSwap(BaseApp):
                 passed = self.callcoinrpc(Coins.PART, 'verifymessage', [offer_addr_from, signature_enc, offer_id.hex() + '_revoke'])
                 return True if passed is True else False  # _possibly_revoked_offers should not contain duplicates
         return False
+
+    def add_connection(self, host, port, peer_pubkey):
+        self.log.info('add_connection %s %d %s', host, port, peer_pubkey.hex())
+        self._network.add_connection(host, port, peer_pubkey)

basicswap/network.py

@@ -6,53 +6,569 @@
 # file LICENSE or http://www.opensource.org/licenses/mit-license.php.
 
 '''
-TODO:
+    Message 2 bytes msg_class, 4 bytes length, [ 2 bytes msg_type, payload ]
+
+    Handshake procedure:
+        node0 connecting to node1
+        node0 send_handshake
+        node1 process_handshake
+        node1 send_ping  - With a version field
+        node0 recv_ping
+            Both nodes are initialised
 '''
 
+import time
+import queue
+import random
 import select
 import socket
+import struct
+import hashlib
 import logging
+import secrets
 import threading
+import traceback
+
+from enum import IntEnum, auto
+from collections import OrderedDict
+from Crypto.Cipher import ChaCha20_Poly1305  # TODO: Add to libsecp256k1/coincurve fork
+from coincurve.keys import PrivateKey, PublicKey
+from basicswap.rfc6979 import (
+    rfc6979_hmac_sha256_initialize,
+    rfc6979_hmac_sha256_generate)
 
 
+START_TOKEN = 0xabcd
+MSG_START_TOKEN = struct.pack('>H', START_TOKEN)
+
+MSG_MAX_SIZE = 0x200000  # 2MB
+
+MSG_HEADER_LEN = 8
+
+
+MAX_SEEN_EPHEM_KEYS = 1000
+TIMESTAMP_LEEWAY = 8
+
+
+class NetMessageTypes(IntEnum):
+    HANDSHAKE = auto()
+    PING = auto()
+    PONG = auto()
+    DATA = auto()
+
+    @classmethod
+    def has_value(cls, value):
+        return value in cls._value2member_map_
+
+
+'''
 class NetMessage:
     def __init__(self):
-        self._msg_type
+        self._msg_class = None  # 2 bytes
+        self._len = None # 4 bytes
+        self._msg_type = None  # 2 bytes
+'''
+
+
+# Ensure handshake keys are not reused by including the time in the msg, mac and key hash
+# Verify timestamp is not too old
+# Add keys to db to catch concurrent attempts, records can be cleared periodically, the timestamp should catch older replay attempts
+class MsgHandshake:
+    __slots__ = ('_timestamp', '_ephem_pk', '_ct', '_mac')
+
+    def __init__(self):
+        pass
+
+    def encode_aad(self):  # Additional Authenticated Data
+        return struct.pack('>H', NetMessageTypes.HANDSHAKE) + \
+            struct.pack('>Q', self._timestamp) + \
+            self._ephem_pk
+
+    def encode(self):
+        return self.encode_aad() + self._ct + self._mac
+
+    def decode(self, msg_mv):
+        o = 2
+        self._timestamp = struct.unpack('>Q', msg_mv[o: o + 8])[0]
+        o += 8
+        self._ephem_pk = bytes(msg_mv[o: o + 33])
+        o += 33
+        self._ct = bytes(msg_mv[o: -16])
+        self._mac = bytes(msg_mv[-16:])
 
 
 class Peer:
-    def __init__(self, address):
+    __slots__ = (
+        '_mx', '_pubkey', '_address', '_socket', '_version', '_ready',
+        '_connected_at', '_last_received_at', '_bytes_sent', '_bytes_received',
+        '_receiving_length', '_receiving_buffer', '_recv_messages', '_misbehaving_score',
+        '_ke', '_km', '_dir', '_sent_nonce', '_recv_nonce', '_last_handshake_at',
+        '_ping_nonce', '_last_ping_at', '_last_ping_rtt')
+
+    def __init__(self, address, socket, pubkey):
+        self._mx = threading.Lock()
+        self._pubkey = pubkey
         self._address = address
+        self._socket = socket
+        self._version = None
+        self._ready = False  # True When handshake is complete
+        self._connected_at = time.time()
+        self._last_received_at = 0
+        self._last_handshake_at = 0
+
+        self._bytes_sent = 0
+        self._bytes_received = 0
+
+        self._receiving_length = 0
+        self._receiving_buffer = None
+        self._recv_messages = queue.Queue()  # Built in mutex
+        self._misbehaving_score = 0
+
+        self._ping_nonce = 0
+        self._last_ping_at = 0  # ms
+        self._last_ping_rtt = 0  # ms
+
+    def close(self):
+        self._socket.close()
+
+
+def listen_thread(cls):
+    timeout = 1.0
+
+    max_bytes = 0x10000
+    while cls._running:
+        # logging.info('[rm] network loop %d', cls._running)
+        readable, writable, errored = select.select(cls._read_sockets, cls._write_sockets, cls._error_sockets, timeout)
+        cls._mx.acquire()
+        try:
+            disconnected_peers = []
+            for s in readable:
+                if s == cls._socket:
+                    peer_socket, address = cls._socket.accept()
+                    logging.info('Connection from %s', address)
+                    cls._peers.append(Peer(address, peer_socket, None))
+                    cls._error_sockets.append(peer_socket)
+                    cls._read_sockets.append(peer_socket)
+                else:
+                    for peer in cls._peers:
+                        if peer._socket == s:
+                            try:
+                                bytes_recv = s.recv(max_bytes, socket.MSG_DONTWAIT)
+                            except socket.error as se:
+                                if se.args[0] not in (socket.EWOULDBLOCK, ):
+                                    logging.error('Receive error %s', str(se))
+                                    disconnected_peers.append(peer)
+                                    continue
+                            except Exception as e:
+                                logging.error('Receive error %s', str(e))
+                                disconnected_peers.append(peer)
+                                continue
+
+                            if len(bytes_recv) < 1:
+                                disconnected_peers.append(peer)
+                                continue
+                            cls.receive_bytes(peer, bytes_recv)
+
+            for s in errored:
+                logging.warning('Socket error')
+
+            for peer in disconnected_peers:
+                cls.disconnect(peer)
+        finally:
+            cls._mx.release()
+
+
+def msg_thread(cls):
+    timeout = 0.1
+    while cls._running:
+        processed = False
+
+        for peer in cls._peers:
+            try:
+                now_us = time.time_ns() // 1000
+                if peer._ready is True:
+                    if now_us - peer._last_ping_at >= 5000000:  # 5 seconds  TODO: Make variable
+                        cls.send_ping(peer)
+                msg = peer._recv_messages.get(False)
+                cls.process_message(peer, msg)
+                processed = True
+            except queue.Empty:
+                pass
+            except Exception as e:
+                logging.warning('process message error %s', str(e))
+                if cls._sc.debug:
+                    traceback.print_exc()
+
+        if processed is False:
+            time.sleep(timeout)
 
 
 class Network:
-    def __init__(self, p2p_host, p2p_port, network_key):
+    __slots__ = (
+        '_p2p_host', '_p2p_port', '_network_key', '_network_pubkey',
+        '_sc', '_peers', '_max_connections', '_running', '_network_thread', '_msg_thread',
+        '_mx', '_socket', '_read_sockets', '_write_sockets', '_error_sockets', '_csprng', '_seen_ephem_keys')
+
+    def __init__(self, p2p_host, p2p_port, network_key, swap_client):
         self._p2p_host = p2p_host
         self._p2p_port = p2p_port
         self._network_key = network_key
+        self._network_pubkey = PublicKey.from_secret(network_key).format()
+        self._sc = swap_client
         self._peers = []
 
         self._max_connections = 10
-        self._running = True
+        self._running = False
 
         self._network_thread = None
+        self._msg_thread = None
         self._mx = threading.Lock()
+        self._socket = None
+        self._read_sockets = []
+        self._write_sockets = []
+        self._error_sockets = []  # Check for error events
+        self._seen_ephem_keys = OrderedDict()
 
     def startNetwork(self):
-        pass
+        self._mx.acquire()
+        try:
+            self._csprng = rfc6979_hmac_sha256_initialize(secrets.token_bytes(32))
+
+            self._running = True
+            self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            self._socket.bind((self._p2p_host, self._p2p_port))
+            self._socket.listen(self._max_connections)
+            self._read_sockets.append(self._socket)
+
+            self._network_thread = threading.Thread(target=listen_thread, args=(self,))
+            self._network_thread.start()
+
+            self._msg_thread = threading.Thread(target=msg_thread, args=(self,))
+            self._msg_thread.start()
+        finally:
+            self._mx.release()
 
     def stopNetwork(self):
-        pass
+        self._mx.acquire()
+        try:
+            self._running = False
+        finally:
+            self._mx.release()
 
-    def listen(self):
-        self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        self._socket.bind((self._p2p_host, self._p2p_port))
-        self._socket.listen(self._max_connections)
+        if self._network_thread:
+            self._network_thread.join()
+        if self._msg_thread:
+            self._msg_thread.join()
 
-        timeout = 1.0
-        while self._running:
-            readable, writable, errored = select.select([self._socket], [], [], timeout)
-            for s in readable:
-                client_socket, address = self._socket.accept()
-                logging.info('Connection from %s', address)
+        self._mx.acquire()
+        try:
+            if self._socket:
+                self._socket.close()
+
+            for peer in self._peers:
+                peer.close()
+        finally:
+            self._mx.release()
+
+    def add_connection(self, host, port, peer_pubkey):
+        self._sc.log.info('Connecting from %s to %s at %s %d', self._network_pubkey.hex(), peer_pubkey.hex(), host, port)
+        self._mx.acquire()
+        try:
+            address = (host, port)
+            peer_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            peer_socket.connect(address)
+            peer = Peer(address, peer_socket, peer_pubkey)
+            self._peers.append(peer)
+            self._error_sockets.append(peer_socket)
+            self._read_sockets.append(peer_socket)
+        finally:
+            self._mx.release()
+
+        self.send_handshake(peer)
+
+    def disconnect(self, peer):
+        self._sc.log.info('Closing peer socket %s', peer._address)
+        self._read_sockets.pop(self._read_sockets.index(peer._socket))
+        self._error_sockets.pop(self._error_sockets.index(peer._socket))
+        peer.close()
+        self._peers.pop(self._peers.index(peer))
+
+    def check_handshake_ephem_key(self, peer, timestamp, ephem_pk, direction=1):
+        # assert ._mx.acquire() ?
+
+        used = self._seen_ephem_keys.get(ephem_pk)
+        if used:
+            raise ValueError('Handshake ephem_pk reused %s peer %s', 'for' if direction == 1 else 'by', used[0])
+
+        self._seen_ephem_keys[ephem_pk] = (peer._address, timestamp)
+
+        while len(self._seen_ephem_keys) > MAX_SEEN_EPHEM_KEYS:
+            self._seen_ephem_keys.popitem(last=False)
+
+    def send_handshake(self, peer):
+        self._sc.log.debug('send_handshake %s', peer._address)
+        peer._mx.acquire()
+        try:
+            # TODO: Drain peer._recv_messages
+            if not peer._recv_messages.empty():
+                self._sc.log.warning('send_handshake %s - Receive queue dumped.', peer._address)
+                while not peer._recv_messages.empty():
+                    peer._recv_messages.get(False)
+
+            msg = MsgHandshake()
+
+            msg._timestamp = int(time.time())
+            key_r = rfc6979_hmac_sha256_generate(self._csprng, 32)
+            k = PrivateKey(key_r)
+            msg._ephem_pk = PublicKey.from_secret(key_r).format()
+            self.check_handshake_ephem_key(peer, msg._timestamp, msg._ephem_pk)
+
+            ss = k.ecdh(peer._pubkey)
+
+            hashed = hashlib.sha512(ss + struct.pack('>Q', msg._timestamp)).digest()
+            peer._ke = hashed[:32]
+            peer._km = hashed[32:]
+
+            nonce = peer._km[24:]
+
+            payload = self._sc._version
+
+            nk = PrivateKey(self._network_key)
+            sig = nk.sign_recoverable(peer._km)
+            payload += sig
+
+            aad = msg.encode_aad()
+            aad += nonce
+            cipher = ChaCha20_Poly1305.new(key=peer._ke, nonce=nonce)
+            cipher.update(aad)
+            msg._ct, msg._mac = cipher.encrypt_and_digest(payload)
+
+            peer._sent_nonce = hashlib.sha256(nonce + msg._mac).digest()
+            peer._recv_nonce = hashlib.sha256(peer._km).digest()  # Init nonce
+
+            peer._last_handshake_at = msg._timestamp
+            peer._ready = False  # Wait for peer to complete handshake
+
+            self.send_msg(peer, msg)
+        finally:
+            peer._mx.release()
+
+    def process_handshake(self, peer, msg_mv):
+        self._sc.log.debug('process_handshake %s', peer._address)
+
+        # TODO: Drain peer._recv_messages
+        if not peer._recv_messages.empty():
+            self._sc.log.warning('process_handshake %s - Receive queue dumped.', peer._address)
+            while not peer._recv_messages.empty():
+                peer._recv_messages.get(False)
+
+        msg = MsgHandshake()
+        msg.decode(msg_mv)
+
+        try:
+            now = int(time.time())
+            if now - peer._last_handshake_at < 30:
+                raise ValueError('Too many handshakes from peer %s', peer._address)
+
+            if abs(msg._timestamp - now) > TIMESTAMP_LEEWAY:
+                raise ValueError('Bad handshake timestamp from peer %s', peer._address)
+
+            self.check_handshake_ephem_key(peer, msg._timestamp, msg._ephem_pk, direction=2)
+
+            nk = PrivateKey(self._network_key)
+            ss = nk.ecdh(msg._ephem_pk)
+
+            hashed = hashlib.sha512(ss + struct.pack('>Q', msg._timestamp)).digest()
+            peer._ke = hashed[:32]
+            peer._km = hashed[32:]
+
+            nonce = peer._km[24:]
+
+            aad = msg.encode_aad()
+            aad += nonce
+            cipher = ChaCha20_Poly1305.new(key=peer._ke, nonce=nonce)
+            cipher.update(aad)
+            plaintext = cipher.decrypt_and_verify(msg._ct, msg._mac)  # Will raise error if mac doesn't match
+
+            peer._version = plaintext[:6]
+            sig = plaintext[6:]
+
+            pk_peer = PublicKey.from_signature_and_message(sig, peer._km)
+            # TODO: Should pk_peer be linked to public data?
+
+            peer._pubkey = pk_peer.format()
+            peer._recv_nonce = hashlib.sha256(nonce + msg._mac).digest()
+            peer._sent_nonce = hashlib.sha256(peer._km).digest()  # Init nonce
+
+            peer._last_handshake_at = msg._timestamp
+            peer._ready = True
+            # Schedule a ping to complete the handshake, TODO: Send here?
+            peer._last_ping_at = 0
+
+        except Exception as e:
+            # TODO: misbehaving
+            self._sc.log.debug('[rm] process_handshake %s', str(e))
+
+    def process_ping(self, peer, msg_mv):
+        nonce = peer._recv_nonce[:24]
+
+        cipher = ChaCha20_Poly1305.new(key=peer._ke, nonce=nonce)
+        cipher.update(msg_mv[0: 2])
+        cipher.update(nonce)
+
+        mac = msg_mv[-16:]
+        plaintext = cipher.decrypt_and_verify(msg_mv[2: -16], mac)
+
+        ping_nonce = struct.unpack('>I', plaintext[:4])[0]
+        # Version is added to a ping following a handshake message
+        if len(plaintext) >= 10:
+            peer._ready = True
+            version = plaintext[4: 10]
+            if peer._version is None:
+                peer._version = version
+                self._sc.log.debug('Set version from ping %s, %s', peer._pubkey.hex(), peer._version.hex())
+
+        peer._recv_nonce = hashlib.sha256(nonce + mac).digest()
+
+        self.send_pong(peer, ping_nonce)
+
+    def process_pong(self, peer, msg_mv):
+        nonce = peer._recv_nonce[:24]
+
+        cipher = ChaCha20_Poly1305.new(key=peer._ke, nonce=nonce)
+        cipher.update(msg_mv[0: 2])
+        cipher.update(nonce)
+
+        mac = msg_mv[-16:]
+        plaintext = cipher.decrypt_and_verify(msg_mv[2: -16], mac)
+
+        pong_nonce = struct.unpack('>I', plaintext[:4])[0]
+
+        if pong_nonce == peer._ping_nonce:
+            peer._last_ping_rtt = (time.time_ns() // 1000) - peer._last_ping_at
+        else:
+            self._sc.log.debug('Pong received out of order %s', peer._address)
+
+        peer._recv_nonce = hashlib.sha256(nonce + mac).digest()
+
+    def send_ping(self, peer):
+        ping_nonce = random.getrandbits(32)
+
+        msg_bytes = struct.pack('>H', NetMessageTypes.PING)
+        nonce = peer._sent_nonce[:24]
+
+        cipher = ChaCha20_Poly1305.new(key=peer._ke, nonce=nonce)
+        cipher.update(msg_bytes)
+        cipher.update(nonce)
+
+        payload = struct.pack('>I', ping_nonce)
+        if peer._last_ping_at == 0:
+            payload += self._sc._version
+        ct, mac = cipher.encrypt_and_digest(payload)
+
+        msg_bytes += ct + mac
+
+        peer._sent_nonce = hashlib.sha256(nonce + mac).digest()
+
+        peer._last_ping_at = time.time_ns() // 1000
+        peer._ping_nonce = ping_nonce
+
+        self.send_msg(peer, msg_bytes)
+
+    def send_pong(self, peer, ping_nonce):
+        msg_bytes = struct.pack('>H', NetMessageTypes.PONG)
+        nonce = peer._sent_nonce[:24]
+
+        cipher = ChaCha20_Poly1305.new(key=peer._ke, nonce=nonce)
+        cipher.update(msg_bytes)
+        cipher.update(nonce)
+
+        payload = struct.pack('>I', ping_nonce)
+        ct, mac = cipher.encrypt_and_digest(payload)
+        msg_bytes += ct + mac
+
+        peer._sent_nonce = hashlib.sha256(nonce + mac).digest()
+
+        self.send_msg(peer, msg_bytes)
+
+    def send_msg(self, peer, msg):
+        msg_encoded = msg if isinstance(msg, bytes) else msg.encode()
+        len_encoded = len(msg_encoded)
+
+        msg_packed = bytearray(MSG_START_TOKEN) + struct.pack('>I', len_encoded) + msg_encoded
+        peer._socket.sendall(msg_packed)
+
+        peer._bytes_sent += len_encoded
+
+    def process_message(self, peer, msg_bytes):
+        logging.info('[rm] process_message %s len %d', peer._address, len(msg_bytes))
+
+        peer._mx.acquire()
+        try:
+            mv = memoryview(msg_bytes)
+            o = 0
+            msg_type = struct.unpack('>H', mv[o: o + 2])[0]
+            if msg_type == NetMessageTypes.HANDSHAKE:
+                self.process_handshake(peer, mv)
+            elif msg_type == NetMessageTypes.PING:
+                self.process_ping(peer, mv)
+            elif msg_type == NetMessageTypes.PONG:
+                self.process_pong(peer, mv)
+            else:
+                self._sc.log.debug('Unknown message type %d', msg_type)
+        finally:
+            peer._mx.release()
+
+    def receive_bytes(self, peer, bytes_recv):
+        # logging.info('[rm] receive_bytes %s %s', peer._address, bytes_recv)
+
+        len_received = len(bytes_recv)
+        peer._last_received_at = time.time()
+        peer._bytes_received += len_received
+
+        invalid_msg = False
+        mv = memoryview(bytes_recv)
+
+        o = 0
+        try:
+            while o < len_received:
+                if peer._receiving_length == 0:
+                    if len(bytes_recv) < MSG_HEADER_LEN:
+                        raise ValueError('Msg too short')
+
+                    if mv[o: o + 2] != MSG_START_TOKEN:
+                        raise ValueError('Invalid start token')
+                    o += 2
+
+                    msg_len = struct.unpack('>I', mv[o: o + 4])[0]
+                    o += 4
+                    if msg_len < 2 or msg_len > MSG_MAX_SIZE:
+                        raise ValueError('Invalid data length')
+
+                    # Precheck msg_type
+                    msg_type = struct.unpack('>H', mv[o: o + 2])[0]
+                    # o += 2  # Don't inc offset, msg includes type
+                    if not NetMessageTypes.has_value(msg_type):
+                        raise ValueError('Invalid msg type')
+
+                    peer._receiving_length = msg_len
+                    len_pkt = (len_received - o)
+                    nc = msg_len if len_pkt > msg_len else len_pkt
+
+                    peer._receiving_buffer = mv[o: o + nc]
+                    o += nc
+                else:
+                    len_to_go = peer._receiving_length - len(peer._receiving_buffer)
+                    len_pkt = (len_received - o)
+                    nc = len_to_go if len_pkt > len_to_go else len_pkt
+                    peer._receiving_buffer = mv[o: o + nc]
+                    o += nc
+                if len(peer._receiving_buffer) == peer._receiving_length:
+                    peer._recv_messages.put(peer._receiving_buffer)
+                    peer._receiving_length = 0
+
+        except Exception as e:
+            if self._sc.debug:
+                self._sc.log.error('Invalid message received from %s %s', peer._address, str(e))
+            # TODO: misbehaving

basicswap/rfc6979.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import hmac
+import hashlib
+
+
+zero = bytes((0,))
+one = bytes((1,))
+
+
+def rfc6979_hmac_sha256_initialize(key):
+    rng_v = one * 32    # RFC6979 3.2.b.
+    rng_k = zero * 32   # RFC6979 3.2.c.
+
+    # RFC6979 3.2.d.
+    h = hmac.new(rng_k, digestmod=hashlib.sha256)
+    h.update(rng_v)
+    h.update(zero)
+    h.update(key)
+    rng_k = h.digest()
+
+    h = hmac.new(rng_k, digestmod=hashlib.sha256)
+    h.update(rng_v)
+    rng_v = h.digest()
+
+    # RFC6979 3.2.f.
+    h = hmac.new(rng_k, digestmod=hashlib.sha256)
+    h.update(rng_v)
+    h.update(one)
+    h.update(key)
+    rng_k = h.digest()
+    h = hmac.new(rng_k, digestmod=hashlib.sha256)
+    h.update(rng_v)
+    rng_v = h.digest()
+
+    return [rng_k, rng_v, False]
+
+
+def rfc6979_hmac_sha256_generate(rng, n):
+    if rng[2]:  # Retry
+        h = hmac.new(rng[0], digestmod=hashlib.sha256)
+        h.update(rng[1])
+        h.update(zero)
+        rng[0] = h.digest()
+        h = hmac.new(rng[0], digestmod=hashlib.sha256)
+        h.update(rng[1])
+        rng[1] = h.digest()
+
+    out = bytes()
+    while n > 0:
+        i = n if n < 32 else 32
+        h = hmac.new(rng[0], digestmod=hashlib.sha256)
+        h.update(rng[1])
+        rng[1] = h.digest()
+        out += rng[1][:i]
+        n -= i
+
+    rng[2] = True
+    return out

requirements.txt

@@ -5,3 +5,4 @@ sqlalchemy
 python-gnupg
 Jinja2
 requests
+pycryptodome

tests/basicswap/test_network.py

@@ -43,6 +43,7 @@ from tests.basicswap.common import (
     checkForks,
     stopDaemons,
     wait_for_offer,
+    delay_for,
     TEST_HTTP_HOST,
     TEST_HTTP_PORT,
     BASE_P2P_PORT,
@@ -142,13 +143,12 @@ def callnoderpc(node_id, method, params=[], wallet=None, base_rpc_port=BASE_RPC_
 
 def run_coins_loop(cls):
     while not stop_test:
-        time.sleep(1.0)
         try:
             if cls.btc_addr is not None:
                 btcRpc('generatetoaddress 1 {}'.format(cls.btc_addr))
         except Exception as e:
             logging.warning('run_coins_loop ' + str(e))
-
+        time.sleep(1.0)
 
 
 def run_loop(cls):
@@ -303,6 +303,10 @@ class Test(unittest.TestCase):
         offer_id = swap_clients[0].postOffer(Coins.PART, Coins.BTC, 100 * COIN, 0.1 * COIN, 100 * COIN, SwapTypes.SELLER_FIRST)
         wait_for_offer(delay_event, swap_clients[1], offer_id)
 
+        swap_clients[1].add_connection('127.0.0.1', BASE_P2P_PORT + 0, swap_clients[0]._network._network_pubkey)
+
+        delay_for(delay_event, 1000)
+
 
 if __name__ == '__main__':
     unittest.main()

tests/basicswap/test_nmc.py

@@ -206,19 +206,19 @@ def signal_handler(sig, frame):
 
 def run_coins_loop(cls):
     while not stop_test:
-        time.sleep(1.0)
         try:
             nmcRpc('generatetoaddress 1 {}'.format(cls.nmc_addr))
             btcRpc('generatetoaddress 1 {}'.format(cls.btc_addr))
         except Exception as e:
             logging.warning('run_coins_loop ' + str(e))
+        time.sleep(1.0)
 
 
 def run_loop(self):
     while not stop_test:
-        time.sleep(1)
         for c in self.swap_clients:
             c.update()
+        time.sleep(1)
 
 
 def make_part_cli_rpc_func(node_id):

tests/basicswap/test_run.py

@@ -215,18 +215,18 @@ def signal_handler(sig, frame):
 def run_coins_loop(cls):
     while not stop_test:
         try:
-            time.sleep(1.0)
             ltcRpc('generatetoaddress 1 {}'.format(cls.ltc_addr))
             btcRpc('generatetoaddress 1 {}'.format(cls.btc_addr))
         except Exception as e:
             logging.warning('run_coins_loop ' + str(e))
+        time.sleep(1.0)
 
 
 def run_loop(cls):
     while not stop_test:
-        time.sleep(1)
         for c in cls.swap_clients:
             c.update()
+        time.sleep(1)
 
 
 def make_part_cli_rpc_func(node_id):

tests/basicswap/test_xmr.py

@@ -238,7 +238,6 @@ def callnoderpc(node_id, method, params=[], wallet=None, base_rpc_port=BASE_RPC_
 
 def run_coins_loop(cls):
     while not stop_test:
-        time.sleep(1.0)
         try:
             if cls.btc_addr is not None:
                 btcRpc('generatetoaddress 1 {}'.format(cls.btc_addr))
@@ -246,6 +245,7 @@ def run_coins_loop(cls):
                 callrpc_xmr_na(XMR_BASE_RPC_PORT + 1, 'generateblocks', {'wallet_address': cls.xmr_addr, 'amount_of_blocks': 1})
         except Exception as e:
             logging.warning('run_coins_loop ' + str(e))
+        time.sleep(1.0)
 
 
 def run_loop(cls):