gossipd: add dying marker to channel_announcement/channel_update.

We don't actually delete them for 12 blocks, but we can't avoid
propagating them.  We don't mark node_announcements, which is a bit
weird, but avoids us tracking logic to un-dying them if a channel is
opened.

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

gossipd/gossip_store.c

@@ -579,6 +579,40 @@ u64 gossip_store_add_private_update(struct gossip_store *gs, const u8 *update)
 	return gossip_store_add(gs, pupdate, 0, false, false, NULL);
 }
 
+void gossip_store_mark_dying(struct gossip_store *gs,
+			     const struct broadcastable *bcast,
+			     int type)
+{
+	const u8 *msg;
+	be16 flags;
+
+	/* Should never get here during loading! */
+	assert(gs->writable);
+
+	/* Should never try to overwrite version */
+	assert(bcast->index);
+
+	/* Sanity check, that this is a channel announcement */
+	msg = gossip_store_get(tmpctx, gs, bcast->index);
+	if (fromwire_peektype(msg) != type) {
+		status_broken("gossip_store incorrect dying msg not %u @%u of %"PRIu64": %s",
+			      type, bcast->index, gs->len, tal_hex(tmpctx, msg));
+		return;
+	}
+
+	if (pread(gs->fd, &flags, sizeof(flags), bcast->index) != sizeof(flags)) {
+		status_failed(STATUS_FAIL_INTERNAL_ERROR,
+			      "Could not read to mark dying at %u/%"PRIu64": %s",
+			      bcast->index, gs->len, strerror(errno));
+	}
+
+	flags |= cpu_to_be16(GOSSIP_STORE_DYING_BIT);
+	if (pwrite(gs->fd, &flags, sizeof(flags), bcast->index) != sizeof(flags))
+		status_failed(STATUS_FAIL_INTERNAL_ERROR,
+			      "Failed writing flags to dying @%u: %s",
+			      bcast->index, strerror(errno));
+}
+
 /* Returns index of following entry. */
 static u32 delete_by_index(struct gossip_store *gs, u32 index, int type)
 {

gossipd/gossip_store.h

@@ -76,6 +76,17 @@ void gossip_store_mark_channel_zombie(struct gossip_store *gs,
 void gossip_store_mark_cupdate_zombie(struct gossip_store *gs,
 				      struct broadcastable *bcast);
 
+/**
+ * Mark this channel_announcement/channel_update as dying.
+ *
+ * We'll clean it up in 12 blocks, but this tells connectd not to gossip
+ * about it.
+ */
+void gossip_store_mark_dying(struct gossip_store *gs,
+			     const struct broadcastable *bcast,
+			     int type);
+
+
 /**
  * Direct store accessor: loads gossip msg back from store.
  *

gossipd/routing.c

@@ -2279,6 +2279,17 @@ void routing_channel_spent(struct routing_state *rstate,
 	msg = towire_gossip_store_chan_dying(tmpctx, &chan->scid, deadline);
 	index = gossip_store_add(rstate->gs, msg, 0, false, false, NULL);
 
+	/* Mark it dying, so we don't gossip it */
+	gossip_store_mark_dying(rstate->gs, &chan->bcast,
+				WIRE_CHANNEL_ANNOUNCEMENT);
+	for (int dir = 0; dir < ARRAY_SIZE(chan->half); dir++) {
+		if (is_halfchan_defined(&chan->half[dir])) {
+			gossip_store_mark_dying(rstate->gs,
+						&chan->half[dir].bcast,
+						WIRE_CHANNEL_UPDATE);
+		}
+	}
+
 	/* Remember locally so we can kill it in 12 blocks */
 	status_debug("channel %s closing soon due"
 		     " to the funding outpoint being spent",

gossipd/test/run-check_channel_announcement.c

@@ -86,6 +86,11 @@ const u8 *gossip_store_get_private_update(const tal_t *ctx UNNEEDED,
 void gossip_store_mark_channel_deleted(struct gossip_store *gs UNNEEDED,
 				       const struct short_channel_id *scid UNNEEDED)
 { fprintf(stderr, "gossip_store_mark_channel_deleted called!\n"); abort(); }
+/* Generated stub for gossip_store_mark_dying */
+void gossip_store_mark_dying(struct gossip_store *gs UNNEEDED,
+			     const struct broadcastable *bcast UNNEEDED,
+			     int type UNNEEDED)
+{ fprintf(stderr, "gossip_store_mark_dying called!\n"); abort(); }
 /* Generated stub for gossip_store_new */
 struct gossip_store *gossip_store_new(struct routing_state *rstate UNNEEDED)
 { fprintf(stderr, "gossip_store_new called!\n"); abort(); }

gossipd/test/run-txout_failure.c

@@ -57,6 +57,11 @@ const u8 *gossip_store_get_private_update(const tal_t *ctx UNNEEDED,
 void gossip_store_mark_channel_deleted(struct gossip_store *gs UNNEEDED,
 				       const struct short_channel_id *scid UNNEEDED)
 { fprintf(stderr, "gossip_store_mark_channel_deleted called!\n"); abort(); }
+/* Generated stub for gossip_store_mark_dying */
+void gossip_store_mark_dying(struct gossip_store *gs UNNEEDED,
+			     const struct broadcastable *bcast UNNEEDED,
+			     int type UNNEEDED)
+{ fprintf(stderr, "gossip_store_mark_dying called!\n"); abort(); }
 /* Generated stub for memleak_add_helper_ */
 void memleak_add_helper_(const tal_t *p UNNEEDED, void (*cb)(struct htable *memtable UNNEEDED,
 						    const tal_t *)){ }