libplugin-pay: incorporate gossip store.

So we can use this for routing determinations.

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

common/gossip_constants.h

@@ -78,4 +78,7 @@
 #define GOSSIP_TOKEN_TIME(dev_fast_gossip_flag) \
 	DEV_FAST_GOSSIP(dev_fast_gossip_flag, 1, 3600)
 
+/* This is where we keep our gossip */
+#define GOSSIP_STORE_FILENAME "gossip_store"
+
 #endif /* LIGHTNING_COMMON_GOSSIP_CONSTANTS_H */

gossipd/gossip_store.c

@@ -24,7 +24,6 @@
 #include <wire/peer_wire.h>
 #include <wire/wire.h>
 
-#define GOSSIP_STORE_FILENAME "gossip_store"
 #define GOSSIP_STORE_TEMP_FILENAME "gossip_store.tmp"
 
 struct gossip_store {

plugins/Makefile

@@ -101,7 +101,7 @@ PLUGIN_COMMON_OBJS :=				\
 	wire/tlvstream.o			\
 	wire/towire.o
 
-plugins/pay: bitcoin/chainparams.o $(PLUGIN_PAY_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_PAY_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS)
+plugins/pay: bitcoin/chainparams.o $(PLUGIN_PAY_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_PAY_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS) common/gossmap.o common/route.o common/dijkstra.o
 $(PLUGIN_PAY_OBJS): $(PLUGIN_PAY_LIB_HEADER)
 
 plugins/autoclean: bitcoin/chainparams.o $(PLUGIN_AUTOCLEAN_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS)
@@ -110,7 +110,7 @@ plugins/txprepare: bitcoin/chainparams.o $(PLUGIN_TXPREPARE_OBJS) $(PLUGIN_LIB_O
 
 plugins/bcli: bitcoin/chainparams.o $(PLUGIN_BCLI_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS)
 
-plugins/keysend: bitcoin/chainparams.o wire/tlvstream.o wire/onion$(EXP)_wiregen.o $(PLUGIN_KEYSEND_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_PAY_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS)
+plugins/keysend: bitcoin/chainparams.o wire/tlvstream.o wire/onion$(EXP)_wiregen.o $(PLUGIN_KEYSEND_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_PAY_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS) common/gossmap.o common/route.o common/dijkstra.o
 $(PLUGIN_KEYSEND_OBJS): $(PLUGIN_PAY_LIB_HEADER)
 
 plugins/spenderp: bitcoin/chainparams.o $(PLUGIN_SPENDER_OBJS) $(PLUGIN_LIB_OBJS) $(PLUGIN_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS)

plugins/libplugin-pay.c

@@ -1,13 +1,19 @@
 #include <bitcoin/preimage.h>
 #include <ccan/array_size/array_size.h>
 #include <ccan/tal/str/str.h>
+#include <common/dijkstra.h>
+#include <common/gossmap.h>
 #include <common/json_helpers.h>
 #include <common/json_stream.h>
+#include <common/memleak.h>
 #include <common/pseudorand.h>
 #include <common/random_select.h>
 #include <common/type_to_string.h>
+#include <errno.h>
 #include <plugins/libplugin-pay.h>
 
+static struct gossmap *gossmap;
+
 /* BOLT #11:
  * * `c` (24): `data_length` variable.
  *    `min_final_cltv_expiry` to use for the last HTLC in the route.
@@ -23,6 +29,15 @@ struct payment *payment_new(tal_t *ctx, struct command *cmd,
 
 	static u64 next_id = 0;
 
+	/* Now we're actually creating a payment, load gossip store */
+	if (!gossmap) {
+		gossmap = notleak_with_children(gossmap_load(NULL,
+							     GOSSIP_STORE_FILENAME));
+		if (!gossmap)
+			plugin_err(cmd->plugin, "Could not load gossmap %s: %s",
+				   GOSSIP_STORE_FILENAME, strerror(errno));
+	}
+
 	p->children = tal_arr(p, struct payment *, 0);
 	p->parent = parent;
 	p->modifiers = mods;