gossipd: add hop-style to nodes to mark whether they speak TLV onion.

We keep the feature bitmap on disk, so we cache this in the struct
explicitly.

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

gossipd/routing.c

@@ -380,6 +380,8 @@ static struct node *new_node(struct routing_state *rstate,
 	n->id = *id;
 	memset(n->chans.arr, 0, sizeof(n->chans.arr));
 	broadcastable_init(&n->bcast);
+	/* We don't know, so assume legacy. */
+	n->hop_style = ROUTE_HOP_LEGACY;
 	n->tokens = TOKEN_MAX;
 	node_map_add(rstate->nodes, n);
 	tal_add_destructor2(n, destroy_node, rstate);
@@ -2510,6 +2512,12 @@ bool routing_add_node_announcement(struct routing_state *rstate,
 	    && node->bcast.timestamp < time_now().ts.tv_sec)
 		rstate->last_timestamp = node->bcast.timestamp;
 
+	if (feature_offered(features, OPT_VAR_ONION))
+		node->hop_style = ROUTE_HOP_TLV;
+	else
+		/* Reset it in case they no longer offer the feature */
+		node->hop_style = ROUTE_HOP_LEGACY;
+
 	if (index)
 		node->bcast.index = index;
 	else {
@@ -2707,6 +2715,7 @@ struct route_hop *get_route(const tal_t *ctx, struct routing_state *rstate,
 		hops[i].amount = total_amount;
 		hops[i].delay = total_delay;
 		hops[i].direction = idx;
+		hops[i].style = n->hop_style;
 
 		/* Since we calculated this route, it should not overflow! */
 		if (!amount_msat_add_fee(&total_amount,

gossipd/routing.h

@@ -133,6 +133,11 @@ HTABLE_DEFINE_TYPE(struct local_chan,
 		   local_chan_map_scid, hash_scid, local_chan_eq_scid,
 		   local_chan_map);
 
+enum route_hop_style {
+	ROUTE_HOP_LEGACY = 1,
+	ROUTE_HOP_TLV = 2,
+};
+
 /* For a small number of channels (by far the most common) we use a simple
  * array, with empty buckets NULL.  For larger, we use a proper hash table,
  * with the extra allocation that implies. */
@@ -147,6 +152,9 @@ struct node {
 	/* Token bucket */
 	u8 tokens;
 
+	/* route_hop_style */
+	enum route_hop_style hop_style;
+
 	/* Channels connecting us to other nodes */
 	union {
 		struct chan_map map;
@@ -320,6 +328,7 @@ struct route_hop {
 	struct node_id nodeid;
 	struct amount_msat amount;
 	u32 delay;
+	enum route_hop_style style;
 };
 
 enum exclude_entry_type {

lightningd/gossip_msg.c

@@ -66,6 +66,7 @@ void fromwire_route_hop(const u8 **pptr, size_t *max, struct route_hop *entry)
 	entry->direction = fromwire_u8(pptr, max);
 	entry->amount = fromwire_amount_msat(pptr, max);
 	entry->delay = fromwire_u32(pptr, max);
+	entry->style = fromwire_u8(pptr, max);
 }
 
 void towire_route_hop(u8 **pptr, const struct route_hop *entry)
@@ -75,6 +76,7 @@ void towire_route_hop(u8 **pptr, const struct route_hop *entry)
 	towire_u8(pptr, entry->direction);
 	towire_amount_msat(pptr, entry->amount);
 	towire_u32(pptr, entry->delay);
+	towire_u8(pptr, entry->style);
 }
 
 void fromwire_route_info(const u8 **pptr, size_t *max, struct route_info *entry)