dev: --dev-gossip-time so gossipd doesn't prune old data.

This is useful for canned data, such as the million channels project.

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

gossipd/gossip_wire.csv

@@ -14,6 +14,7 @@ gossipctl_init,,alias,32*u8
 gossipctl_init,,update_channel_interval,u32
 gossipctl_init,,num_announcable,u16
 gossipctl_init,,announcable,num_announcable*struct wireaddr
+gossipctl_init,,dev_gossip_time,?u32
 
 # Pass JSON-RPC getnodes call through
 gossip_getnodes_request,3005

gossipd/gossipd.c

@@ -1859,6 +1859,7 @@ static struct io_plan *gossip_init(struct io_conn *conn,
 				   const u8 *msg)
 {
 	u32 update_channel_interval;
+	u32 *dev_gossip_time;
 
 	if (!fromwire_gossipctl_init(daemon, msg,
 				     /* 60,000 ms
@@ -1871,7 +1872,8 @@ static struct io_plan *gossip_init(struct io_conn *conn,
 				     /* 1 week in seconds
 				      * (unless --dev-channel-update-interval) */
 				     &update_channel_interval,
-				     &daemon->announcable)) {
+				     &daemon->announcable,
+				     &dev_gossip_time)) {
 		master_badmsg(WIRE_GOSSIPCTL_INIT, msg);
 	}
 
@@ -1879,8 +1881,8 @@ static struct io_plan *gossip_init(struct io_conn *conn,
 	daemon->rstate = new_routing_state(daemon,
 					   chainparams_by_chainhash(&daemon->chain_hash),
 					   &daemon->id,
-					   update_channel_interval * 2);
+					   update_channel_interval * 2,
-
+					   dev_gossip_time);
 	/* Load stored gossip messages */
 	gossip_store_load(daemon->rstate, daemon->rstate->store);
 

gossipd/routing.c

@@ -82,7 +82,8 @@ static struct node_map *empty_node_map(const tal_t *ctx)
 struct routing_state *new_routing_state(const tal_t *ctx,
 					const struct chainparams *chainparams,
 					const struct pubkey *local_id,
-					u32 prune_timeout)
+					u32 prune_timeout,
+					const u32 *dev_gossip_time)
 {
 	struct routing_state *rstate = tal(ctx, struct routing_state);
 	rstate->nodes = empty_node_map(rstate);
@@ -99,6 +100,16 @@ struct routing_state *new_routing_state(const tal_t *ctx,
 	rstate->pending_node_map = tal(ctx, struct pending_node_map);
 	pending_node_map_init(rstate->pending_node_map);
 
+
+#if DEVELOPER
+	if (dev_gossip_time) {
+		rstate->gossip_time = tal(rstate, struct timeabs);
+		rstate->gossip_time->ts.tv_sec = *dev_gossip_time;
+		rstate->gossip_time->ts.tv_nsec = 0;
+	} else
+		rstate->gossip_time = NULL;
+#endif
+
 	return rstate;
 }
 
@@ -270,7 +281,7 @@ static void init_half_chan(struct routing_state *rstate,
 	c->message_flags = 0;
 	/* We haven't seen channel_update: make it halfway to prune time,
 	 * which should be older than any update we'd see. */
-	c->last_timestamp = time_now().ts.tv_sec - rstate->prune_timeout/2;
+	c->last_timestamp = gossip_time_now(rstate).ts.tv_sec - rstate->prune_timeout/2;
 }
 
 static void bad_gossip_order(const u8 *msg, const char *source,
@@ -1273,7 +1284,7 @@ u8 *handle_channel_update(struct routing_state *rstate, const u8 *update TAKES,
 	 *  - if the `timestamp` is unreasonably far in the future:
 	 *    - MAY discard the `channel_update`.
 	 */
-	if (timestamp > time_now().ts.tv_sec + rstate->prune_timeout) {
+	if (timestamp > gossip_time_now(rstate).ts.tv_sec + rstate->prune_timeout) {
 		status_debug("Received channel_update for %s with far time %u",
 			     type_to_string(tmpctx, struct short_channel_id,
 					    &short_channel_id),
@@ -1282,7 +1293,7 @@ u8 *handle_channel_update(struct routing_state *rstate, const u8 *update TAKES,
 	}
 
 	/* Note: we can consider old timestamps a case of "instant prune" too */
-	if (timestamp < time_now().ts.tv_sec - rstate->prune_timeout) {
+	if (timestamp < gossip_time_now(rstate).ts.tv_sec - rstate->prune_timeout) {
 		status_debug("Received channel_update for %s with old time %u",
 			     type_to_string(tmpctx, struct short_channel_id,
 					    &short_channel_id),
@@ -1721,7 +1732,7 @@ void routing_failure(struct routing_state *rstate,
 
 void route_prune(struct routing_state *rstate)
 {
-	u64 now = time_now().ts.tv_sec;
+	u64 now = gossip_time_now(rstate).ts.tv_sec;
 	/* Anything below this highwater mark ought to be pruned */
 	const s64 highwater = now - rstate->prune_timeout;
 	const tal_t *pruned = tal(NULL, char);
@@ -1799,3 +1810,12 @@ bool handle_local_add_channel(struct routing_state *rstate, const u8 *msg)
 	new_chan(rstate, &scid, &rstate->local_id, &remote_node_id, sat);
 	return true;
 }
+
+struct timeabs gossip_time_now(const struct routing_state *rstate)
+{
+#if DEVELOPER
+	if (rstate->gossip_time)
+		return *rstate->gossip_time;
+#endif
+	return time_now();
+}

gossipd/routing.h

@@ -214,6 +214,11 @@ struct routing_state {
 	/* Cache for txout queries that failed. Allows us to skip failed
 	 * checks if we get another announcement for the same scid. */
 	UINTMAP(bool) txout_failures;
+
+#if DEVELOPER
+	/* Override local time for gossip messages */
+	struct timeabs *gossip_time;
+#endif
 };
 
 static inline struct chan *
@@ -234,7 +239,8 @@ struct route_hop {
 struct routing_state *new_routing_state(const tal_t *ctx,
 					const struct chainparams *chainparams,
 					const struct pubkey *local_id,
-					u32 prune_timeout);
+					u32 prune_timeout,
+					const u32 *dev_gossip_time);
 
 /**
  * Add a new bidirectional channel from id1 to id2 with the given
@@ -345,4 +351,12 @@ bool handle_local_add_channel(struct routing_state *rstate, const u8 *msg);
 void memleak_remove_routing_tables(struct htable *memtable,
 				   const struct routing_state *rstate);
 #endif
+
+/**
+ * Get the local time.
+ *
+ * This gets overridden in dev mode so we can use canned (stale) gossip.
+ */
+struct timeabs gossip_time_now(const struct routing_state *rstate);
+
 #endif /* LIGHTNING_GOSSIPD_ROUTING_H */

gossipd/test/run-bench-find_route.c

@@ -225,7 +225,7 @@ int main(int argc, char *argv[])
 	setup_tmpctx();
 
 	me = nodeid(0);
-	rstate = new_routing_state(tmpctx, NULL, &me, 0);
+	rstate = new_routing_state(tmpctx, NULL, &me, 0, NULL);
 	opt_register_noarg("--perfme", opt_set_bool, &perfme,
 			   "Run perfme-start and perfme-stop around benchmark");
 

gossipd/test/run-find_route-specific.c

@@ -184,7 +184,7 @@ int main(void)
 			   strlen("02cca6c5c966fcf61d121e3a70e03a1cd9eeeea024b26ea666ce974d43b242e636"),
 			   &d);
 
-	rstate = new_routing_state(tmpctx, NULL, &a, 0);
+	rstate = new_routing_state(tmpctx, NULL, &a, 0, NULL);
 
 	/* [{'active': True, 'short_id': '6990:2:1/1', 'fee_per_kw': 10, 'delay': 5, 'message_flags': 0, 'channel_flags': 1, 'destination': '0230ad0e74ea03976b28fda587bb75bdd357a1938af4424156a18265167f5e40ae', 'source': '02ea622d5c8d6143f15ed3ce1d501dd0d3d09d3b1c83a44d0034949f8a9ab60f06', 'last_update': 1504064344}, */
 

gossipd/test/run-find_route.c

@@ -213,7 +213,7 @@ int main(void)
 
 	memset(&tmp, 'a', sizeof(tmp));
 	pubkey_from_privkey(&tmp, &a);
-	rstate = new_routing_state(tmpctx, NULL, &a, 0);
+	rstate = new_routing_state(tmpctx, NULL, &a, 0, NULL);
 
 	new_node(rstate, &a);
 

lightningd/gossip_control.c

@@ -164,7 +164,13 @@ void gossip_init(struct lightningd *ld, int connectd_fd)
 	    get_offered_globalfeatures(tmpctx),
 	    ld->rgb,
 	    ld->alias, ld->config.channel_update_interval,
-	    ld->announcable);
+	    ld->announcable,
+#if DEVELOPER
+	    ld->dev_gossip_time ? &ld->dev_gossip_time: NULL
+#else
+	    NULL
+#endif
+		);
 	subd_send_msg(ld->gossip, msg);
 }
 

lightningd/lightningd.c

@@ -116,6 +116,7 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->dev_disconnect_fd = -1;
 	ld->dev_subdaemon_fail = false;
 	ld->dev_allow_localhost = false;
+	ld->dev_gossip_time = 0;
 #endif
 
 	/*~ These are CCAN lists: an embedded double-linked list.  It's not

lightningd/lightningd.h

@@ -196,6 +196,9 @@ struct lightningd {
 	/* Allow and accept localhost node_announcement addresses */
 	bool dev_allow_localhost;
 
+	/* Timestamp to use for gossipd, iff non-zero */
+	u32 dev_gossip_time;
+
 	/* Things we've marked as not leaking. */
 	const void **notleaks;
 #endif /* DEVELOPER */

lightningd/options.c

@@ -475,6 +475,10 @@ static void dev_register_opts(struct lightningd *ld)
 	    "--dev-channel-update-interval=<s>", opt_set_u32, opt_show_u32,
 	    &ld->config.channel_update_interval,
 	    "Time in seconds between channel updates for our own channels.");
+
+	opt_register_arg("--dev-gossip-time", opt_set_u32, opt_show_u32,
+			 &ld->dev_gossip_time,
+			 "UNIX time to override gossipd to use.");
 }
 #endif