lightningd: keep features arrays for connected peers.

As a side-effect, we only print them for connected peers (which avoids
an O(n^2) traversal).

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

lightningd/opening_control.c

@@ -596,7 +596,8 @@ static struct uncommitted_channel *
 new_uncommitted_channel(struct lightningd *ld,
 			struct funding_channel *fc,
 			const struct pubkey *peer_id,
-			const struct wireaddr_internal *addr)
+			const struct wireaddr_internal *addr,
+			const u8 *gfeatures, const u8 *lfeatures)
 {
 	struct uncommitted_channel *uc = tal(ld, struct uncommitted_channel);
 	char *idname;
@@ -604,7 +605,7 @@ new_uncommitted_channel(struct lightningd *ld,
 	/* We make a new peer if necessary. */
 	uc->peer = peer_by_id(ld, peer_id);
 	if (!uc->peer)
-		uc->peer = new_peer(ld, 0, peer_id, addr);
+		uc->peer = new_peer(ld, 0, peer_id, addr, gfeatures, lfeatures);
 
 	if (uc->peer->uncommitted_channel)
 		return tal_free(uc);
@@ -686,7 +687,7 @@ u8 *peer_accept_channel(const tal_t *ctx,
 			const struct pubkey *peer_id,
 			const struct wireaddr_internal *addr,
 			const struct crypto_state *cs,
-			const u8 *gfeatures UNUSED, const u8 *lfeatures UNUSED,
+			const u8 *gfeatures, const u8 *lfeatures,
 			int peer_fd, int gossip_fd,
 			const struct channel_id *channel_id,
 			const u8 *open_msg)
@@ -700,7 +701,8 @@ u8 *peer_accept_channel(const tal_t *ctx,
 	assert(fromwire_peektype(open_msg) == WIRE_OPEN_CHANNEL);
 
 	/* Fails if there's already one */
-	uc = new_uncommitted_channel(ld, NULL, peer_id, addr);
+	uc = new_uncommitted_channel(ld, NULL, peer_id, addr,
+				     gfeatures, lfeatures);
 	if (!uc)
 		return towire_errorfmt(ctx, channel_id,
 				       "Multiple channels unsupported");
@@ -766,7 +768,7 @@ static void peer_offer_channel(struct lightningd *ld,
 			       struct funding_channel *fc,
 			       const struct wireaddr_internal *addr,
 			       const struct crypto_state *cs,
-			       const u8 *gfeatures UNUSED, const u8 *lfeatures UNUSED,
+			       const u8 *gfeatures, const u8 *lfeatures,
 			       int peer_fd, int gossip_fd)
 {
 	u8 *msg;
@@ -778,7 +780,8 @@ static void peer_offer_channel(struct lightningd *ld,
 	list_del_from(&ld->fundchannels, &fc->list);
 	tal_del_destructor(fc, remove_funding_channel_from_list);
 
-	fc->uc = new_uncommitted_channel(ld, fc, &fc->peerid, addr);
+	fc->uc = new_uncommitted_channel(ld, fc, &fc->peerid, addr,
+					 gfeatures, lfeatures);
 
 	/* We asked to release this peer, but another raced in?  Corner case,
 	 * close this is easiest. */

lightningd/peer_control.c

@@ -80,7 +80,8 @@ static void copy_to_parent_log(const char *prefix,
 
 struct peer *new_peer(struct lightningd *ld, u64 dbid,
 		      const struct pubkey *id,
-		      const struct wireaddr_internal *addr)
+		      const struct wireaddr_internal *addr,
+		      const u8 *gfeatures, const u8 *lfeatures)
 {
 	/* We are owned by our channels, and freed manually by destroy_channel */
 	struct peer *peer = tal(NULL, struct peer);
@@ -96,6 +97,10 @@ struct peer *new_peer(struct lightningd *ld, u64 dbid,
 		peer->addr.itype = ADDR_INTERNAL_WIREADDR;
 		peer->addr.u.wireaddr.type = ADDR_TYPE_PADDING;
 	}
+	peer->global_features = tal_dup_arr(peer, u8,
+					    gfeatures, tal_count(gfeatures), 0);
+	peer->local_features = tal_dup_arr(peer, u8,
+					   lfeatures, tal_count(lfeatures), 0);
 	list_head_init(&peer->channels);
 	peer->direction = get_channel_direction(&peer->ld->id, &peer->id);
 
@@ -704,18 +709,6 @@ struct getpeers_args {
 	struct pubkey *specific_id;
 };
 
-static void json_add_features(struct json_result *response,
-			      const struct peer_features *pf)
-{
-	json_add_hex(response, "global_features",
-		     pf->global_features,
-		     tal_len(pf->global_features));
-
-	json_add_hex(response, "local_features",
-		     pf->local_features,
-		     tal_len(pf->local_features));
-}
-
 static void connectd_getpeers_complete(struct subd *connectd, const u8 *msg,
 				      const int *fds UNUSED,
 				      struct getpeers_args *gpa)
@@ -756,6 +749,9 @@ static void connectd_getpeers_complete(struct subd *connectd, const u8 *msg,
 		}
 		json_add_bool(response, "connected", connected);
 
+		/* If it's not connected, features are unreliable: we don't
+		 * store them in the database, and they would only reflect
+		 * their features *last* time they connected. */
 		if (connected) {
 			json_array_start(response, "netaddr");
 			if (p->addr.itype != ADDR_INTERNAL_WIREADDR
@@ -765,14 +761,13 @@ static void connectd_getpeers_complete(struct subd *connectd, const u8 *msg,
 							       struct wireaddr_internal,
 							       &p->addr));
 			json_array_end(response);
-		}
+			json_add_hex(response, "global_features",
+				     p->global_features,
+				     tal_len(p->global_features));
 
-		/* Search connectd reply for this ID, to add extra info. */
-		for (size_t i = 0; i < tal_count(ids); i++) {
-			if (pubkey_eq(&ids[i], &p->id)) {
-				json_add_features(response, pf[i]);
-				break;
-			}
+			json_add_hex(response, "local_features",
+				     p->local_features,
+				     tal_len(p->local_features));
 		}
 
 		json_array_start(response, "channels");
@@ -905,7 +900,13 @@ static void connectd_getpeers_complete(struct subd *connectd, const u8 *msg,
 		/* Fake state. */
 		json_add_string(response, "state", "GOSSIPING");
 		json_add_pubkey(response, "id", ids+i);
-		json_add_features(response, pf[i]);
+		json_add_hex(response, "global_features",
+			     pf[i]->global_features,
+			     tal_len(pf[i]->global_features));
+
+		json_add_hex(response, "local_features",
+			     pf[i]->local_features,
+			     tal_len(pf[i]->local_features));
 		json_array_start(response, "netaddr");
 		if (addrs[i].itype != ADDR_INTERNAL_WIREADDR
 		    || addrs[i].u.wireaddr.type != ADDR_TYPE_PADDING)

lightningd/peer_control.h

@@ -41,6 +41,9 @@ struct peer {
 	/* Where we connected to, or it connected from. */
 	struct wireaddr_internal addr;
 
+	/* We keep a copy of their feature bits */
+	const u8 *local_features, *global_features;
+
 	/* If we open a channel our direction will be this */
 	u8 direction;
 
@@ -54,7 +57,8 @@ struct peer *find_peer_by_dbid(struct lightningd *ld, u64 dbid);
 
 struct peer *new_peer(struct lightningd *ld, u64 dbid,
 		      const struct pubkey *id,
-		      const struct wireaddr_internal *addr);
+		      const struct wireaddr_internal *addr,
+		      const u8 *gfeatures, const u8 *lfeatures);
 
 /* Also removes from db. */
 void delete_peer(struct peer *peer);

wallet/test/run-wallet.c

@@ -762,7 +762,7 @@ static bool test_channel_crud(struct lightningd *ld, const tal_t *ctx)
 	mempat(scriptpubkey, tal_len(scriptpubkey));
 	c1.first_blocknum = 1;
 	c1.final_key_idx = 1337;
-	p = new_peer(ld, 0, &pk, NULL);
+	p = new_peer(ld, 0, &pk, NULL, NULL, NULL);
 	c1.peer = p;
 	c1.dbid = wallet_get_channel_dbid(w);
 	c1.state = CHANNELD_NORMAL;

wallet/wallet.c

@@ -522,7 +522,7 @@ static struct peer *wallet_peer_load(struct wallet *w, const u64 dbid)
 		addrp = NULL;
 
 	peer = new_peer(w->ld, sqlite3_column_int64(stmt, 0),
-			&id, addrp);
+			&id, addrp, NULL, NULL);
 	db_stmt_done(stmt);
 
 	return peer;