lightningd/channel: send and receive htlc_fulfilled messages.

Includes a fix for the direction we fulfill.

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

lightningd/channel/channel.c

@@ -376,6 +376,11 @@ static void start_commit_timer(struct peer *peer)
 					  send_commit, peer);
 }
 
+static void theirs_fulfilled(const struct htlc *htlc, struct peer *peer)
+{
+	/* FIXME: Tell master, so it can disarm timer. */
+}
+
 static void handle_peer_commit_sig(struct peer *peer, const u8 *msg)
 {
 	tal_t *tmpctx = tal_tmpctx(peer);
@@ -388,8 +393,7 @@ static void handle_peer_commit_sig(struct peer *peer, const u8 *msg)
 	const u8 **wscripts;
 	size_t i;
 
-	/* FIXME: Handle theirsfulfilled! */
-	if (!channel_rcvd_commit(peer->channel, NULL, peer)) {
+	if (!channel_rcvd_commit(peer->channel, theirs_fulfilled, peer)) {
 		/* BOLT #2:
 		 *
 		 * A node MUST NOT send a `commitment_signed` message which
@@ -677,6 +681,46 @@ static void handle_peer_revoke_and_ack(struct peer *peer, const u8 *msg)
 	start_commit_timer(peer);
 }
 
+static void handle_peer_fulfill_htlc(struct peer *peer, const u8 *msg)
+{
+	struct channel_id channel_id;
+	u64 id;
+	struct preimage preimage;
+	enum channel_remove_err e;
+
+	if (!fromwire_update_fulfill_htlc(msg, NULL, &channel_id,
+					  &id, &preimage)) {
+		peer_failed(io_conn_fd(peer->peer_conn),
+			    &peer->pcs.cs,
+			    &peer->channel_id,
+			    WIRE_CHANNEL_PEER_BAD_MESSAGE,
+			    "Bad update_fulfill_htlc %s", tal_hex(msg, msg));
+	}
+
+	e = channel_fulfill_htlc(peer->channel, LOCAL, id, &preimage);
+	switch (e) {
+	case CHANNEL_ERR_REMOVE_OK:
+		/* FIXME: tell master about HTLC preimage */
+		start_commit_timer(peer);
+		return;
+	/* These shouldn't happen, because any offered HTLC (which would give
+	 * us the preimage) should have timed out long before.  If we
+	 * were to get preimages from other sources, this could happen. */
+	case CHANNEL_ERR_NO_SUCH_ID:
+	case CHANNEL_ERR_ALREADY_FULFILLED:
+	case CHANNEL_ERR_HTLC_UNCOMMITTED:
+	case CHANNEL_ERR_HTLC_NOT_IRREVOCABLE:
+	case CHANNEL_ERR_BAD_PREIMAGE:
+		peer_failed(io_conn_fd(peer->peer_conn),
+			    &peer->pcs.cs,
+			    &peer->channel_id,
+			    WIRE_CHANNEL_PEER_BAD_MESSAGE,
+			    "Bad update_fulfill_htlc: failed to fulfill %"
+			    PRIu64 " error %u", id, e);
+	}
+	abort();
+}
+
 static struct io_plan *peer_in(struct io_conn *conn, struct peer *peer, u8 *msg)
 {
 	enum wire_type type = fromwire_peektype(msg);
@@ -719,6 +763,9 @@ static struct io_plan *peer_in(struct io_conn *conn, struct peer *peer, u8 *msg)
 	case WIRE_REVOKE_AND_ACK:
 		handle_peer_revoke_and_ack(peer, msg);
 		goto done;
+	case WIRE_UPDATE_FULFILL_HTLC:
+		handle_peer_fulfill_htlc(peer, msg);
+		goto done;
 	case WIRE_INIT:
 	case WIRE_ERROR:
 	case WIRE_OPEN_CHANNEL:
@@ -729,7 +776,6 @@ static struct io_plan *peer_in(struct io_conn *conn, struct peer *peer, u8 *msg)
 
 	case WIRE_SHUTDOWN:
 	case WIRE_CLOSING_SIGNED:
-	case WIRE_UPDATE_FULFILL_HTLC:
 	case WIRE_UPDATE_FAIL_HTLC:
 	case WIRE_UPDATE_FAIL_MALFORMED_HTLC:
 	case WIRE_UPDATE_FEE:

lightningd/peer_control.c

@@ -648,6 +648,7 @@ static void handle_localpay(struct peer *peer,
 			    u32 cltv_expiry,
 			    const struct sha256 *payment_hash)
 {
+	u8 *msg;
 	struct invoice *invoice = find_unpaid(peer->ld->dstate.invoices,
 					      payment_hash);
 
@@ -691,7 +692,8 @@ static void handle_localpay(struct peer *peer,
 	log_info(peer->ld->log, "Resolving invoice '%s' with HTLC %"PRIu64,
 		 invoice->label, htlc_id);
 
-	/* FIXME: msg = towire_channel_fulfill_htlc(htlc->id, &invoice->r); */
+	msg = towire_channel_fulfill_htlc(peer, htlc_id, &invoice->r);
+	subd_send_msg(peer->owner, take(msg));
 	resolve_invoice(&peer->ld->dstate, invoice);
 }
 

lightningd/test/test-basic

@@ -74,6 +74,12 @@ check "lcli1 getlog debug | $FGREP 'Sending commit_sig with 1 htlc sigs'"
 check "lcli2 getlog debug | $FGREP 'Resolving invoice '\'testpayment1\'' with HTLC 1'"
 [ `lcli2 listinvoice testpayment1 | get_field complete` = true ]
 
+#check "lcli1 getpeers | get_field msatoshi_to_us | $FGREP -w 900000000"
+#[ `lcli1 getpeers | get_field msatoshi_to_us` = 900000000 ]
+#[ `lcli1 getpeers | get_field msatoshi_to_them` = 100000000 ]
+#[ `lcli2 getpeers | get_field msatoshi_to_them` = 900000000 ]
+#[ `lcli2 getpeers | get_field msatoshi_to_us` = 100000000 ]
+
 lcli1 stop
 lcli2 stop