gossip: Disable local channels after loading the gossip_store

We don't have any connection yet, so how could they be active? Disable both
sides to avoid trying to route through them or telling others to use them as
`contact_points` in invoices.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

gossipd/gossip.c

@@ -1900,6 +1900,26 @@ static void gossip_disable_channel(struct routing_state *rstate, struct chan *ch
 			      tal_hex(tmpctx, err));
 }
 
+static void gossip_disable_local_channels(struct daemon *daemon)
+{
+	struct node *local_node =
+	    get_node(daemon->rstate, &daemon->rstate->local_id);
+	struct chan *c;
+	size_t i;
+
+	/* We don't have a local_node, so we don't have any channels yet
+	 * either */
+	if (!local_node)
+		return;
+
+	for (i=0; i<tal_count(local_node->chans); i++) {
+		c = local_node->chans[i];
+		c->half[0].flags |= ROUTING_FLAGS_DISABLED;
+		c->half[1].flags |= ROUTING_FLAGS_DISABLED;
+		gossip_disable_channel(daemon->rstate, c);
+	}
+}
+
 /* Parse an incoming gossip init message and assign config variables
  * to the daemon.
  */
@@ -1939,6 +1959,10 @@ static struct io_plan *gossip_init(struct daemon_conn *master,
 	/* Load stored gossip messages */
 	gossip_store_load(daemon->rstate, daemon->rstate->store);
 
+	/* Now disable all local channels, they can't be connected yet. */
+	gossip_disable_local_channels(daemon);
+
+
 	new_reltimer(&daemon->timers, daemon,
 		     time_from_sec(daemon->rstate->prune_timeout/4),
 		     gossip_refresh_network, daemon);

tests/test_gossip.py

@@ -58,3 +58,39 @@ def test_gossip_pruning(node_factory, bitcoind):
     assert scid2 not in [c['short_channel_id'] for c in l2.rpc.listchannels()['channels']]
     assert l3.info['id'] not in [n['nodeid'] for n in l1.rpc.listnodes()['nodes']]
     assert l3.info['id'] not in [n['nodeid'] for n in l2.rpc.listnodes()['nodes']]
+
+
+@unittest.skipIf(not DEVELOPER, "needs --dev-broadcast-interval, --dev-no-reconnect")
+def test_gossip_disable_channels(node_factory, bitcoind):
+    """Simple test to check that channels get disabled correctly on disconnect and
+    reenabled upon reconnecting
+
+    """
+    opts = {'dev-no-reconnect': None, 'may_reconnect': True}
+    l1, l2 = node_factory.get_nodes(2, opts=opts)
+
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+    scid = l1.fund_channel(l2, 10**6)
+    bitcoind.rpc.generate(5)
+
+    def count_active(node):
+        chans = node.rpc.listchannels()['channels']
+        active = [c for c in chans if c['active']]
+        return len(active)
+
+    l1.wait_channel_active(scid)
+    l2.wait_channel_active(scid)
+
+    assert(count_active(l1) == 2)
+    assert(count_active(l2) == 2)
+
+    l2.restart()
+
+    wait_for(lambda: count_active(l1) == 0)
+    assert(count_active(l2) == 0)
+
+    # Now reconnect, they should re-enable the channels
+    l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
+
+    wait_for(lambda: count_active(l1) == 2)
+    wait_for(lambda: count_active(l2) == 2)

tests/test_lightningd.py

@@ -2505,10 +2505,10 @@ class LightningDTests(BaseLightningDTests):
         too.
         """
         opts = {'dev-no-reconnect': None}
-        l1 = self.node_factory.get_node(options=opts)
+        l1 = self.node_factory.get_node(options=opts, may_reconnect=True)
-        l2 = self.node_factory.get_node(options=opts)
+        l2 = self.node_factory.get_node(options=opts, may_reconnect=True)
-        l3 = self.node_factory.get_node(options=opts)
+        l3 = self.node_factory.get_node(options=opts, may_reconnect=True)
-        l4 = self.node_factory.get_node(options=opts)
+        l4 = self.node_factory.get_node(options=opts, may_reconnect=True)
 
         l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
         l2.rpc.connect(l3.info['id'], 'localhost', l3.port)
@@ -2532,8 +2532,14 @@ class LightningDTests(BaseLightningDTests):
         wait_for(lambda: count_active(l2) == 4)
         wait_for(lambda: count_active(l3) == 6)  # 4 public + 2 local
 
-        # l1 restarts and doesn't connect, but loads from persisted store
+        # l1 restarts and doesn't connect, but loads from persisted store, all
+        # local channels should be disabled, leaving only the two l2 <-> l3
+        # directions
         l1.restart()
+        wait_for(lambda: count_active(l1) == 2)
+
+        # Now reconnect, they should re-enable the two l1 <-> l2 directions
+        l1.rpc.connect(l2.info['id'], 'localhost', l2.port)
         wait_for(lambda: count_active(l1) == 4)
 
         # Now spend the funding tx, generate a block and see others deleting the
@@ -2563,6 +2569,8 @@ class LightningDTests(BaseLightningDTests):
         # Finally, it should also remember the deletion after a restart
         l3.restart()
         l4.restart()
+        l2.rpc.connect(l3.info['id'], 'localhost', l3.port)
+        l3.rpc.connect(l4.info['id'], 'localhost', l4.port)
         wait_for(lambda: count_active(l3) == 4)  # 2 public + 2 local
 
         # Both l3 and l4 should remember their local-only channel