common/read_peer_msg: don't try to handle reestablish/reopen.

Let the callers do that (only channeld needs to do this).

We temporarily send an error on unknown reestablish in openingd, as
this mimic previous behavior and avoids breaking tests (it does leave
a BROKEN message in the logs though, so
test_funding_external_wallet_corners needs to ignore that for now.

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

channeld/channeld.c

@@ -2668,6 +2668,15 @@ static void peer_reconnect(struct peer *peer,
 				 tal_hex(msg, msg));
 	}
 
+	if (!channel_id_eq(&channel_id, &peer->channel_id)) {
+		peer_failed_err(peer->pps,
+				&channel_id,
+				"bad reestablish msg for unknown channel %s: %s",
+				type_to_string(tmpctx, struct channel_id,
+					       &channel_id),
+				tal_hex(msg, msg));
+	}
+
 	status_debug("Got reestablish commit=%"PRIu64" revoke=%"PRIu64,
 		     next_commitment_number,
 		     next_revocation_number);

common/read_peer_msg.c

@@ -162,7 +162,6 @@ bool handle_peer_gossip_or_error(struct per_peer_state *pps,
 {
 	char *err;
 	bool warning;
-	struct channel_id actual;
 
 #if DEVELOPER
 	/* Any odd-typed unknown message is handled by the caller, so if we
@@ -200,18 +199,6 @@ bool handle_peer_gossip_or_error(struct per_peer_state *pps,
 		goto handled;
 	}
 
-	/* They're talking about a different channel? */
-	if (is_wrong_channel(msg, channel_id, &actual)) {
-		status_debug("Rejecting %s for unknown channel_id %s",
-			     peer_wire_name(fromwire_peektype(msg)),
-			     type_to_string(tmpctx, struct channel_id, &actual));
-		sync_crypto_write(pps,
-				  take(towire_errorfmt(NULL, &actual,
-						       "Multiple channels"
-						       " unsupported")));
-		goto handled;
-	}
-
 	return false;
 
 handled:

common/read_peer_msg.h

@@ -62,8 +62,8 @@ bool is_wrong_channel(const u8 *msg, const struct channel_id *expected,
  * @msg: the peer message (only taken if returns true).
  *
  * This returns true if it handled the packet: a gossip packet (forwarded
- * to gossipd), an error packet (causes peer_failed_received_errmsg or
- * ignored), or a message about the wrong channel (sends sync error reply).
+ * to gossipd), or an error packet (causes peer_failed_received_errmsg or
+ * ignored).
  */
 bool handle_peer_gossip_or_error(struct per_peer_state *pps,
 				 const struct channel_id *channel_id,

openingd/openingd.c

@@ -1170,12 +1170,21 @@ static u8 *handle_peer_in(struct state *state)
 					&state->channel_id, false, msg))
 		return NULL;
 
-	sync_crypto_write(state->pps,
-			  take(towire_warningfmt(NULL,
-						 extract_channel_id(msg, &channel_id) ? &channel_id : NULL,
-						 "Unexpected message %s: %s",
-						 peer_wire_name(t),
-						 tal_hex(tmpctx, msg))));
+	if (extract_channel_id(msg, &channel_id)) {
+		sync_crypto_write(state->pps,
+				  take(towire_errorfmt(NULL,
+						       &channel_id,
+						       "Unexpected message %s: %s",
+						       peer_wire_name(t),
+						       tal_hex(tmpctx, msg))));
+	} else {
+		sync_crypto_write(state->pps,
+				  take(towire_warningfmt(NULL,
+							 NULL,
+							 "Unexpected message %s: %s",
+							 peer_wire_name(t),
+							 tal_hex(tmpctx, msg))));
+	}
 
 	/* FIXME: We don't actually want master to try to send an
 	 * error, since peer is transient.  This is a hack.

tests/test_connection.py

@@ -1149,7 +1149,7 @@ def test_funding_by_utxos(node_factory, bitcoind):
 @pytest.mark.developer("needs dev_forget_channel")
 @pytest.mark.openchannel('v1')
 def test_funding_external_wallet_corners(node_factory, bitcoind):
-    l1 = node_factory.get_node(may_reconnect=True)
+    l1 = node_factory.get_node(may_reconnect=True, allow_broken_log=True)
     l2 = node_factory.get_node(may_reconnect=True)
 
     amount = 2**24
@@ -1242,7 +1242,7 @@ def test_funding_external_wallet_corners(node_factory, bitcoind):
 
     # on reconnect, channel should get destroyed
     l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
-    l1.daemon.wait_for_log('Rejecting WIRE_CHANNEL_REESTABLISH for unknown channel_id')
+    l1.daemon.wait_for_log('Unexpected message WIRE_CHANNEL_REESTABLISH')
     wait_for(lambda: len(l1.rpc.listpeers()['peers']) == 0)
     wait_for(lambda: len(l2.rpc.listpeers()['peers']) == 0)