lightningd: implement gossip_get_txout/gossip_get_txout_reply.

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

gossipd/gossip.c

@@ -1601,6 +1601,9 @@ static struct io_plan *recv_req(struct io_conn *conn, struct daemon_conn *master
 	case WIRE_GOSSIP_GETPEERS_REQUEST:
 		return get_peers(conn, daemon, master->msg_in);
 
+	case WIRE_GOSSIP_GET_TXOUT_REPLY:
+		/* FIXME */
+
 	/* We send these, we don't receive them */
 	case WIRE_GOSSIPCTL_RELEASE_PEER_REPLY:
 	case WIRE_GOSSIPCTL_RELEASE_PEER_REPLYFAIL:
@@ -1616,6 +1619,7 @@ static struct io_plan *recv_req(struct io_conn *conn, struct daemon_conn *master
 	case WIRE_GOSSIP_GET_UPDATE_REPLY:
 	case WIRE_GOSSIP_SEND_GOSSIP:
 	case WIRE_GOSSIP_LOCAL_ADD_CHANNEL:
+	case WIRE_GOSSIP_GET_TXOUT:
 		break;
 	}
 

gossipd/gossip_wire.csv

@@ -157,3 +157,14 @@ gossip_local_add_channel,,cltv_expiry_delta,u16
 gossip_local_add_channel,,htlc_minimum_msat,u64
 gossip_local_add_channel,,fee_base_msat,u32
 gossip_local_add_channel,,fee_proportional_millionths,u32
+
+# Gossipd->master get this tx output please.
+gossip_get_txout,3018
+gossip_get_txout,,short_channel_id,struct short_channel_id
+
+# master->gossipd here is the output, or empty if none.
+gossip_get_txout_reply,3118
+gossip_get_txout_reply,,short_channel_id,struct short_channel_id
+gossip_get_txout_reply,,len,u16
+gossip_get_txout_reply,,outscript,len*u8
+

lightningd/gossip_control.c

@@ -1,3 +1,5 @@
+#include "bitcoind.h"
+#include "chaintopology.h"
 #include "gossip_control.h"
 #include "lightningd.h"
 #include "peer_control.h"
@@ -53,6 +55,31 @@ static void peer_nongossip(struct subd *gossip, const u8 *msg,
 			    peer_fd, gossip_fd, in_pkt);
 }
 
+static void got_txout(struct bitcoind *bitcoind,
+		      const struct bitcoin_tx_output *output,
+		      struct short_channel_id *scid)
+{
+	/* output will be NULL if it wasn't found */
+	subd_send_msg(bitcoind->ld->gossip,
+		      towire_gossip_get_txout_reply(scid, scid, output->script));
+	tal_free(scid);
+}
+
+static void get_txout(struct subd *gossip, const u8 *msg)
+{
+	struct short_channel_id *scid = tal(gossip, struct short_channel_id);
+
+	if (!fromwire_gossip_get_txout(msg, NULL, scid))
+		fatal("Gossip gave bad GOSSIP_GET_TXOUT message %s",
+		      tal_hex(msg, msg));
+
+	/* FIXME: Block less than 6 deep? */
+
+	bitcoind_getoutput(gossip->ld->topology->bitcoind,
+			   scid->blocknum, scid->txnum, scid->outnum,
+			   got_txout, scid);
+}
+
 static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 {
 	enum gossip_wire_type t = fromwire_peektype(msg);
@@ -72,6 +99,7 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 	case WIRE_GOSSIPCTL_PEER_ADDRHINT:
 	case WIRE_GOSSIP_GET_UPDATE:
 	case WIRE_GOSSIP_SEND_GOSSIP:
+	case WIRE_GOSSIP_GET_TXOUT_REPLY:
 	/* This is a reply, so never gets through to here. */
 	case WIRE_GOSSIP_GET_UPDATE_REPLY:
 	case WIRE_GOSSIP_GETNODES_REPLY:
@@ -97,6 +125,9 @@ static unsigned gossip_msg(struct subd *gossip, const u8 *msg, const int *fds)
 			return 2;
 		peer_nongossip(gossip, msg, fds[0], fds[1]);
 		break;
+	case WIRE_GOSSIP_GET_TXOUT:
+		get_txout(gossip, msg);
+		break;
 	}
 	return 0;
 }