common/gossmap: remove now-unused private flag.

The only way you'll see private channel_updates is if you put them
there yourself with localmods.

I also renamed the confusing gossmap_chan_capacity to gossmap_chan_has_capacity.

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

common/gossmap.c

@@ -318,14 +318,9 @@ static u32 init_chan_arr(struct gossmap_chan *chan_arr, size_t start)
 	for (i = start; i < tal_count(chan_arr) - 1; i++) {
 		chan_arr[i].cann_off = i + 1;
 		chan_arr[i].plus_scid_off = 0;
-		/* We don't need to initialize this, *but* on some platforms
-		 * (ppc, arm64) valgrind complains: this is a bitfield shared
-		 * with plus_scid_off */
-		chan_arr[i].private = false;
 	}
 	chan_arr[i].cann_off = UINT_MAX;
 	chan_arr[i].plus_scid_off = 0;
-	chan_arr[i].private = false;
 	return start;
 }
 
@@ -350,13 +345,11 @@ static struct gossmap_chan *next_free_chan(struct gossmap *map)
 static struct gossmap_chan *new_channel(struct gossmap *map,
 					u32 cannounce_off,
 					u32 plus_scid_off,
-					bool private,
 					u32 n1idx, u32 n2idx)
 {
 	struct gossmap_chan *chan = next_free_chan(map);
 
 	chan->cann_off = cannounce_off;
-	chan->private = private;
 	chan->plus_scid_off = plus_scid_off;
 	chan->cupdate_off[0] = chan->cupdate_off[1] = 0;
 	memset(chan->half, 0, sizeof(chan->half));
@@ -421,8 +414,7 @@ void gossmap_remove_node(struct gossmap *map, struct gossmap_node *node)
  *     * [`point`:`node_id_2`]
  */
 static struct gossmap_chan *add_channel(struct gossmap *map,
-					size_t cannounce_off,
-					bool private)
+					size_t cannounce_off)
 {
 	/* Note that first two bytes are message type */
 	const size_t feature_len_off = 2 + (64 + 64 + 64 + 64);
@@ -440,12 +432,9 @@ static struct gossmap_chan *add_channel(struct gossmap *map,
 	map_nodeid(map, cannounce_off + plus_scid_off + 8, &node_id[0]);
 	map_nodeid(map, cannounce_off + plus_scid_off + 8 + PUBKEY_CMPR_LEN, &node_id[1]);
 
-	/* We can have a channel upgrade from private->public, but
-	 * that's the only time we get duplicates */
+	/* We 1should not get duplicates. */
 	scid.u64 = map_be64(map, cannounce_off + plus_scid_off);
-	chan = gossmap_find_chan(map, &scid);
-	if (chan)
-		gossmap_remove_chan(map, chan);
+	assert(!gossmap_find_chan(map, &scid));
 
 	/* We carefully map pointers to indexes, since new_node can move them! */
 	n[0] = gossmap_find_node(map, &node_id[0]);
@@ -460,7 +449,7 @@ static struct gossmap_chan *add_channel(struct gossmap *map,
 	else
 		nidx[1] = new_node(map);
 
-	chan = new_channel(map, cannounce_off, plus_scid_off, private,
+	chan = new_channel(map, cannounce_off, plus_scid_off,
 			   nidx[0], nidx[1]);
 
 	/* Now we have a channel, we can add nodes to htable */
@@ -635,7 +624,7 @@ static bool map_catchup(struct gossmap *map, size_t *num_rejected)
 		off = map->map_end + sizeof(ghdr);
 		type = map_be16(map, off);
 		if (type == WIRE_CHANNEL_ANNOUNCEMENT)
-			add_channel(map, off, false);
+			add_channel(map, off);
 		else if (type == WIRE_CHANNEL_UPDATE)
 			num_bad += !update_channel(map, off);
 		else if (type == WIRE_GOSSIP_STORE_DELETE_CHAN)
@@ -902,8 +891,7 @@ void gossmap_apply_localmods(struct gossmap *map,
 				continue;
 
 			/* Create new channel, pointing into local. */
-			chan = add_channel(map, map->map_size + mod->local_off,
-					   true);
+			chan = add_channel(map, map->map_size + mod->local_off);
 		}
 
 		/* Save old, overwrite (keep nodeidx) */
@@ -995,6 +983,12 @@ void gossmap_node_get_id(const struct gossmap *map,
 		   + 8 + PUBKEY_CMPR_LEN*dir, id);
 }
 
+bool gossmap_chan_is_localmod(const struct gossmap *map,
+			      const struct gossmap_chan *c)
+{
+	return c->cann_off >= map->map_size;
+}
+
 bool gossmap_chan_get_capacity(const struct gossmap *map,
 			       const struct gossmap_chan *c,
 			       struct amount_sat *amount)
@@ -1004,16 +998,9 @@ bool gossmap_chan_get_capacity(const struct gossmap *map,
 	u16 type;
 
 	/* Fail for local channels */
-	if (c->cann_off >= map->map_size)
+	if (gossmap_chan_is_localmod(map, c))
 		return false;
 
-	/* For private, we need to go back WIRE_GOSSIP_STORE_PRIVATE_CHANNEL,
-	 * which is 8 (satoshis) + 2 (len) */
-	if (c->private) {
-		*amount = amount_sat(map_be64(map, c->cann_off - 8 - 2));
-		return true;
-	}
-
 	/* Skip over this record to next; expect a gossip_store_channel_amount */
 	off = c->cann_off - sizeof(ghdr);
 	map_copy(map, off, &ghdr, sizeof(ghdr));
@@ -1113,9 +1100,9 @@ struct gossmap_chan *gossmap_next_chan(const struct gossmap *map,
 	return chan_iter(map, prev - map->chan_arr + 1);
 }
 
-bool gossmap_chan_capacity(const struct gossmap_chan *chan,
-			   int direction,
-			   struct amount_msat amount)
+bool gossmap_chan_has_capacity(const struct gossmap_chan *chan,
+			       int direction,
+			       struct amount_msat amount)
 {
 	if (amount_msat_less_fp16(amount, chan->half[direction].htlc_min))
 		return false;
@@ -1133,14 +1120,10 @@ u8 *gossmap_chan_get_announce(const tal_t *ctx,
 {
 	u16 len;
 	u8 *msg;
-	u32 pre_off;
 
-	/* We need to go back to struct gossip_hdr to get len */
-	if (c->private)
-		pre_off = 2 + 8 + 2 + sizeof(struct gossip_hdr);
-	else
-		pre_off = sizeof(struct gossip_hdr);
-	len = map_be16(map, c->cann_off - pre_off
+	if (gossmap_chan_is_localmod(map, c))
+		return NULL;
+	len = map_be16(map, c->cann_off - sizeof(struct gossip_hdr)
 		       + offsetof(struct gossip_hdr, len));
 
 	msg = tal_arr(ctx, u8, len);

common/gossmap.h

@@ -18,9 +18,8 @@ struct gossmap_node {
 
 struct gossmap_chan {
 	u32 cann_off;
-	u32 private: 1;
 	/* Technically redundant, but we have a hole anyway: from cann_off */
-	u32 plus_scid_off: 31;
+	u32 plus_scid_off;
 	/* Offsets of cupdates (0 if missing).  Logically inside half_chan,
 	 * but that would add padding. */
 	u32 cupdate_off[2];
@@ -85,6 +84,10 @@ void gossmap_apply_localmods(struct gossmap *map,
 void gossmap_remove_localmods(struct gossmap *map,
 			      const struct gossmap_localmods *localmods);
 
+/* Is this channel a localmod? */
+bool gossmap_chan_is_localmod(const struct gossmap *map,
+			      const struct gossmap_chan *c);
+
 /* Each channel has a unique (low) index. */
 u32 gossmap_node_idx(const struct gossmap *map, const struct gossmap_node *node);
 u32 gossmap_chan_idx(const struct gossmap *map, const struct gossmap_chan *chan);
@@ -124,7 +127,7 @@ bool gossmap_chan_get_capacity(const struct gossmap *map,
 			       const struct gossmap_chan *c,
 			       struct amount_sat *amount);
 
-/* Get the announcement msg which created this chan */
+/* Get the announcement msg which created this chan (NULL for localmods) */
 u8 *gossmap_chan_get_announce(const tal_t *ctx,
 			      const struct gossmap *map,
 			      const struct gossmap_chan *c);
@@ -180,9 +183,9 @@ struct gossmap_node *gossmap_nth_node(const struct gossmap *map,
 				      int n);
 
 /* Can this channel send this amount? */
-bool gossmap_chan_capacity(const struct gossmap_chan *chan,
-			   int direction,
-			   struct amount_msat amount);
+bool gossmap_chan_has_capacity(const struct gossmap_chan *chan,
+			       int direction,
+			       struct amount_msat amount);
 
 /* Remove a channel from the map (warning! realloc can move gossmap_chan
  * and gossmap_node ptrs!) */

common/route.c

@@ -15,7 +15,7 @@ bool route_can_carry_even_disabled(const struct gossmap *map,
 		return false;
 	/* Amount 0 is a special "ignore min" probe case */
 	if (!amount_msat_eq(amount, AMOUNT_MSAT(0))
-	    && !gossmap_chan_capacity(c, dir, amount))
+	    && !gossmap_chan_has_capacity(c, dir, amount))
 		return false;
 	return true;
 }

common/test/run-gossmap_canned.c

@@ -332,7 +332,7 @@ int main(int argc, char *argv[])
 
 	assert(short_channel_id_from_str("110x1x0", 7, &scid12));
 	assert(gossmap_find_chan(map, &scid12));
-	assert(!gossmap_find_chan(map, &scid12)->private);
+	assert(!gossmap_chan_is_localmod(map, gossmap_find_chan(map, &scid12)));
 	assert(gossmap_chan_get_capacity(map, gossmap_find_chan(map, &scid12),
 					 &capacity));
 	assert(amount_sat_eq(capacity, AMOUNT_SAT(1000000)));

common/test/run-gossmap_local.c

@@ -358,9 +358,9 @@ int main(int argc, char *argv[])
 	assert(short_channel_id_from_str("103x1x0", 7, &scid23));
 	assert(short_channel_id_from_str("110x1x0", 7, &scid12));
 	assert(gossmap_find_chan(map, &scid23));
-	assert(!gossmap_find_chan(map, &scid23)->private);
+	assert(!gossmap_chan_is_localmod(map, gossmap_find_chan(map, &scid23)));
 	assert(gossmap_find_chan(map, &scid12));
-	assert(!gossmap_find_chan(map, &scid12)->private);
+	assert(!gossmap_chan_is_localmod(map, gossmap_find_chan(map, &scid12)));
 	assert(gossmap_chan_get_capacity(map, gossmap_find_chan(map, &scid23),
 					 &capacity));
 	assert(amount_sat_eq(capacity, AMOUNT_SAT(1000000)));

plugins/topology.c

@@ -264,7 +264,7 @@ static void json_add_halfchan(struct json_stream *response,
 		json_add_node_id(response, "destination", &node_id[!dir]);
 		json_add_short_channel_id(response, "short_channel_id", &scid);
 		json_add_num(response, "direction", dir);
-		json_add_bool(response, "public", !c->private);
+		json_add_bool(response, "public", !gossmap_chan_is_localmod(gossmap, c));
 
 		if (c->private) {
 			/* Local additions don't have a channel_update
@@ -666,7 +666,7 @@ listpeerchannels_listincoming_done(struct command *cmd,
 		json_add_u32(js, "cltv_expiry_delta", ourchan->half[!dir].delay);
 		json_add_amount_msat(js, "incoming_capacity_msat",
 				     peer_capacity(gossmap, me, peer, ourchan));
-		json_add_bool(js, "public", !ourchan->private);
+		json_add_bool(js, "public", !gossmap_chan_is_localmod(gossmap, ourchan));
 		peer_features = gossmap_node_get_features(tmpctx, gossmap, peer);
 		if (peer_features)
 			json_add_hex_talarr(js, "peer_features", peer_features);