routing: Reading the channel_id from routes passed in from JSONRPC

daemon/routing.c

@@ -477,6 +477,25 @@ static bool get_slash_u32(const char **arg, u32 *v)
 	return (endp == *arg);
 }
 
+bool short_channel_id_from_str(const char *str, size_t strlen,
+			       struct short_channel_id *dst)
+{
+	u32 blocknum, txnum;
+	u16 outnum;
+	int matches;
+
+	char buf[strlen + 1];
+	memcpy(buf, str, strlen);
+	buf[strlen] = 0;
+
+	matches = sscanf(buf, "%u:%u:%hu", &blocknum, &txnum, &outnum);
+	dst->blocknum = blocknum;
+	dst->txnum = txnum;
+	dst->outnum = outnum;
+	return matches == 3;
+}
+
+
 /* srcid/dstid/base/var/delay/minblocks */
 char *opt_add_route(const char *arg, struct lightningd_state *dstate)
 {

daemon/routing.h

@@ -180,4 +180,7 @@ struct route_hop *get_route(tal_t *ctx, struct routing_state *rstate,
  * the direction bit the matching channel should get */
 #define get_channel_direction(from, to) (pubkey_cmp(from, to) > 0)
 
+bool short_channel_id_from_str(const char *str, size_t strlen,
+			       struct short_channel_id *dst);
+
 #endif /* LIGHTNING_DAEMON_ROUTING_H */

lightningd/pay.c

@@ -193,9 +193,14 @@ static void json_sendpay(struct command *cmd,
 	end = json_next(routetok);
 	n_hops = 0;
 	ids = tal_arr(cmd, struct pubkey, n_hops);
-	hoppayloads = tal_arr(cmd, struct hoppayload, 0);
+
+	/* Switching to hop_data in the next commit, and it causes a
+	 * double free in peer_control otherwise */
+	hoppayloads = tal_arr(NULL, struct hoppayload, 0);
 	for (t = routetok + 1; t < end; t = json_next(t)) {
-		const jsmntok_t *amttok, *idtok, *delaytok;
+		const jsmntok_t *amttok, *idtok, *delaytok, *chantok;
+		/* Will populate into hop_data in the next commit */
+		struct short_channel_id scid;
 
 		if (t->type != JSMN_OBJECT) {
 			command_fail(cmd, "route %zu '%.*s' is not an object",
@@ -207,8 +212,9 @@ static void json_sendpay(struct command *cmd,
 		amttok = json_get_member(buffer, t, "msatoshi");
 		idtok = json_get_member(buffer, t, "id");
 		delaytok = json_get_member(buffer, t, "delay");
-		if (!amttok || !idtok || !delaytok) {
-			command_fail(cmd, "route %zu needs msatoshi/id/delay",
+		chantok = json_get_member(buffer, t, "channel");
+		if (!amttok || !idtok || !delaytok || !chantok) {
+			command_fail(cmd, "route %zu needs msatoshi/id/channel/delay",
 				     n_hops);
 			return;
 		}
@@ -233,6 +239,12 @@ static void json_sendpay(struct command *cmd,
 
 		tal_resize(&ids, n_hops+1);
 		memset(&ids[n_hops], 0, sizeof(ids[n_hops]));
+		if (!short_channel_id_from_str(buffer + chantok->start,
+					chantok->end - chantok->start,
+					&scid)) {
+			command_fail(cmd, "route %zu invalid id", n_hops);
+			return;
+		}
 		if (!pubkey_from_hexstr(buffer + idtok->start,
 					idtok->end - idtok->start,
 					&ids[n_hops])) {

tests/test_lightningd.py

@@ -218,7 +218,12 @@ class LightningDTests(BaseLightningDTests):
         rhash = l2.rpc.invoice(amt, 'testpayment2')['rhash']
         assert l2.rpc.listinvoice('testpayment2')[0]['complete'] == False
 
-        routestep = { 'msatoshi' : amt, 'id' : l2.info['id'], 'delay' : 5}
+        routestep = {
+            'msatoshi' : amt,
+            'id' : l2.info['id'],
+            'delay' : 5,
+            'channel': '1:1:1'
+        }
 
         # Insufficient funds.
         rs = copy.deepcopy(routestep)
@@ -257,7 +262,7 @@ class LightningDTests(BaseLightningDTests):
         # Overpaying by "only" a factor of 2 succeeds.
         rhash = l2.rpc.invoice(amt, 'testpayment3')['rhash']
         assert l2.rpc.listinvoice('testpayment3')[0]['complete'] == False
-        routestep = { 'msatoshi' : amt * 2, 'id' : l2.info['id'], 'delay' : 5}
+        routestep = { 'msatoshi' : amt * 2, 'id' : l2.info['id'], 'delay' : 5, 'channel': '1:1:1'}
         l1.rpc.sendpay(to_json([routestep]), rhash)
         assert l2.rpc.listinvoice('testpayment3')[0]['complete'] == True