From 2597672df5df387818396105e471fa6128dd008e Mon Sep 17 00:00:00 2001
From: Sylvain Bellemare <sbellem@gmail.com>
Date: Tue, 3 Jul 2018 11:17:52 +0100
Subject: [PATCH] Add CONF message phase to BA

Addresses #59
---
 honeybadgerbft/core/binaryagreement.py | 65 ++++++++++++++++++++++++--
 1 file changed, 60 insertions(+), 5 deletions(-)

diff --git a/honeybadgerbft/core/binaryagreement.py b/honeybadgerbft/core/binaryagreement.py
index 142a0d0..f38370e 100644
--- a/honeybadgerbft/core/binaryagreement.py
+++ b/honeybadgerbft/core/binaryagreement.py
@@ -2,12 +2,15 @@
 from gevent.event import Event
 
 from collections import defaultdict
+from distutils.util import strtobool
+from os import environ
 import logging
 
 from honeybadgerbft.exceptions import RedundantMessageError, AbandonedNodeError
 
 
 logger = logging.getLogger(__name__)
+CONF_PHASE = strtobool(environ.get('CONF_PHASE', '1'))
 
 
 def binaryagreement(sid, pid, N, f, coin, input, decide, broadcast, receive):
@@ -28,7 +31,9 @@ def binaryagreement(sid, pid, N, f, coin, input, decide, broadcast, receive):
     # Messages received are routed to either a shared coin, the broadcast, or AUX
     est_values = defaultdict(lambda: [set(), set()])
     aux_values = defaultdict(lambda: [set(), set()])
+    conf_values = defaultdict(lambda: {(0,): set(), (1,): set(), (0, 1): set()})
     est_sent = defaultdict(lambda: [False, False])
+    conf_sent = defaultdict(lambda: {(0,): False, (1,): False, (0, 1): False})
     bin_values = defaultdict(set)
 
     # This event is triggered whenever bin_values or aux_values changes
@@ -100,6 +105,27 @@ def _recv():
 
                 bv_signal.set()
 
+            elif msg[0] == 'CONF' and CONF_PHASE:
+                _, r, v = msg
+                assert v in ((0,), (1,), (0, 1))
+                if sender in conf_values[r][v]:
+                    logger.warn(f'Redundant CONF received {msg} by {sender}',
+                                extra={'nodeid': pid, 'epoch': r})
+                    # FIXME: Raise for now to simplify things & be consistent
+                    # with how other TAGs are handled. Will replace the raise
+                    # with a continue statement as part of
+                    # https://github.com/initc3/HoneyBadgerBFT-Python/issues/10
+                    raise RedundantMessageError(
+                        'Redundant CONF received {}'.format(msg))
+
+                conf_values[r][v].add(sender)
+                logger.debug(
+                    f'add v = {v} to conf_value[{r}] = {conf_values[r]}',
+                    extra={'nodeid': pid, 'epoch': r},
+                )
+
+                bv_signal.set()
+
     # Translate mmr14 broadcast into coin.broadcast
     # _coin_broadcast = lambda (r, sig): broadcast(('COIN', r, sig))
     # _coin_recv = Queue()
@@ -159,6 +185,39 @@ def _recv():
 
         logger.debug(f'Completed AUX phase with values = {values}',
                      extra={'nodeid': pid, 'epoch': r})
+
+        # XXX CONF phase
+        logger.debug(
+            f'block until at least N-f ({N-f}) CONF values are received',
+            extra={'nodeid': pid, 'epoch': r})
+        if CONF_PHASE and not conf_sent[r][tuple(values)]:
+            conf_sent[r][tuple(values)] = True
+            logger.debug(f"broadcast {('CONF', r, tuple(values))}",
+                         extra={'nodeid': pid, 'epoch': r})
+            broadcast(('CONF', r, tuple(bin_values[r])))
+            while True:
+                logger.debug(
+                    f'looping ... conf_values[r] is: {conf_values[r]}',
+                    extra={'nodeid': pid, 'epoch': r},
+                )
+                if 1 in bin_values[r] and len(conf_values[r][(1,)]) >= N - f:
+                    values = set((1,))
+                    break
+                if 0 in bin_values[r] and len(conf_values[r][(0,)]) >= N - f:
+                    values = set((0,))
+                    break
+                if (sum(len(senders) for conf_value, senders in
+                        conf_values[r].items() if senders and
+                        set(conf_value).issubset(bin_values[r])) >= N - f):
+                    values = set((0, 1))
+                    break
+
+                bv_signal.clear()
+                bv_signal.wait()
+
+        logger.debug(f'Completed CONF phase with values = {values}',
+                     extra={'nodeid': pid, 'epoch': r})
+
         logger.debug(
             f'Block until receiving the common coin value',
             extra={'nodeid': pid, 'epoch': r},
@@ -174,8 +233,6 @@ def _recv():
                 s=s,
                 already_decided=already_decided,
                 decide=decide,
-                nodeid=pid,
-                epoch=r,
             )
         except AbandonedNodeError:
             # print('[sid:%s] [pid:%d] QUITTING in round %d' % (sid,pid,r)))
@@ -187,13 +244,11 @@ def _recv():
         r += 1
 
 
-def set_new_estimate(*, values, s, already_decided, decide, nodeid, epoch):
+def set_new_estimate(*, values, s, already_decided, decide):
     if len(values) == 1:
         v = next(iter(values))
         if v == s:
             if already_decided is None:
-                logger.debug(f'DECIDE on value {v}',
-                             extra={'nodeid': pid, 'epoch': epoch})
                 already_decided = v
                 decide(v)
             elif already_decided == v: