channel: remove awaiting_revoke_and_ack flag.

We can tell this more generically because the count of revocations
received != count of commitments sent.  This is the correct condition
which allows us to restore the test we had to eliminate in
c3cb7f1c85.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

channeld/channel.c

@@ -692,7 +692,9 @@ static void send_commit(struct peer *peer)
 
 	/* FIXME: Document this requirement in BOLT 2! */
 	/* We can't send two commits in a row. */
-	if (channel_awaiting_revoke_and_ack(peer->channel)) {
+	if (peer->revocations_received != peer->next_index[REMOTE] - 1) {
+		assert(peer->revocations_received
+		       == peer->next_index[REMOTE] - 2);
 		status_trace("Can't send commit: waiting for revoke_and_ack");
 		/* Mark this as done and try again. */
 		peer->commit_timer = NULL;
@@ -1141,9 +1143,12 @@ static struct io_plan *handle_peer_revoke_and_ack(struct io_conn *conn,
 			    "Bad revoke_and_ack %s", tal_hex(msg, msg));
 	}
 
-	/* FIXME: We can get unexpected revoke_and_ack due to retransmit; we
-	 * should really detect this case and set
-	 * channel_awaiting_revoke_and_ack; normally it will be true here. */
+	if (peer->revocations_received != peer->next_index[REMOTE] - 2) {
+		peer_failed(io_conn_fd(peer->peer_conn),
+			    &peer->pcs.cs,
+			    &peer->channel_id,
+			    "Unexpected revoke_and_ack");
+	}
 
 	/* BOLT #2:
 	 *
@@ -1178,7 +1183,7 @@ static struct io_plan *handle_peer_revoke_and_ack(struct io_conn *conn,
 		status_trace("No commits outstanding after recv revoke_and_ack");
 
 	/* Tell master about things this locks in, wait for response */
-	msg = got_revoke_msg(tmpctx, peer->next_index[REMOTE] - 2,
+	msg = got_revoke_msg(tmpctx, peer->revocations_received++,
 			     &old_commit_secret, &next_per_commit,
 			     changed_htlcs);
 	master_wait_sync_reply(tmpctx, peer, take(msg),
@@ -1605,8 +1610,7 @@ static void resend_commitment(struct peer *peer, const struct changed_htlc *last
 	msg_enqueue(&peer->peer_out, take(msg));
 	tal_free(commit_sigs);
 
-	/* Now we have to wait for revoke_and_ack */
-	peer->channel->awaiting_revoke_and_ack = true;
+	assert(peer->revocations_received == peer->next_index[REMOTE] - 2);
 }
 
 static void peer_reconnect(struct peer *peer)

channeld/full_channel.c

@@ -773,8 +773,6 @@ bool channel_sending_commit(struct channel *channel,
 		     htlcs, "sending_commit");
 	channel->changes_pending[REMOTE] = false;
 
-	assert(!channel->awaiting_revoke_and_ack);
-	channel->awaiting_revoke_and_ack = true;
 	return true;
 }
 
@@ -795,8 +793,6 @@ bool channel_rcvd_revoke_and_ack(struct channel *channel,
 	if (change & HTLC_LOCAL_F_PENDING)
 		channel->changes_pending[LOCAL] = true;
 
-	channel->awaiting_revoke_and_ack = false;
-
 	/* For funder, ack also means time to apply new feerate locally. */
 	if (channel->funder == LOCAL &&
 	    (channel->view[LOCAL].feerate_per_kw
@@ -862,11 +858,6 @@ bool channel_sending_revoke_and_ack(struct channel *channel)
 	return channel->changes_pending[REMOTE];
 }
 
-bool channel_awaiting_revoke_and_ack(const struct channel *channel)
-{
-	return channel->awaiting_revoke_and_ack;
-}
-
 bool channel_has_htlcs(const struct channel *channel)
 {
 	struct htlc_map_iter it;

channeld/full_channel.h

@@ -241,14 +241,6 @@ bool channel_rcvd_commit(struct channel *channel,
  * anything changed for the remote commitment (ie. send a new commit).*/
 bool channel_sending_revoke_and_ack(struct channel *channel);
 
-/**
- * channel_awaiting_revoke_and_ack: are we waiting for revoke_and_ack?
- * @channel: the channel
- *
- * If true, we can't send a new commit message.
- */
-bool channel_awaiting_revoke_and_ack(const struct channel *channel);
-
 /**
  * channel_has_htlcs: are there any (live) HTLCs at all in channel?
  * @channel: the channel

common/initial_channel.c

@@ -40,7 +40,6 @@ struct channel *new_initial_channel(const tal_t *ctx,
 	channel->htlcs = NULL;
 	channel->changes_pending[LOCAL] = channel->changes_pending[REMOTE]
 		= false;
-	channel->awaiting_revoke_and_ack = false;
 
 	channel->view[LOCAL].feerate_per_kw
 		= channel->view[REMOTE].feerate_per_kw

common/initial_channel.h

@@ -55,9 +55,6 @@ struct channel {
 	/* Do we have changes pending for ourselves/other? */
 	bool changes_pending[NUM_SIDES];
 
-	/* Are we waiting for their revoke_and_ack? */
-	bool awaiting_revoke_and_ack;
-
 	/* What it looks like to each side. */
 	struct channel_view view[NUM_SIDES];
 };