channeld: get current block height when an HTLC fails.

We need it to put in the error code for
WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS.

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

channeld/channel_wire.csv

@@ -48,6 +48,7 @@ msgdata,channel_init,fulfilled_sides,enum side,num_fulfilled
 msgdata,channel_init,num_failed,u16,
 msgdata,channel_init,failed,failed_htlc,num_failed
 msgdata,channel_init,failed_sides,enum side,num_failed
+msgdata,channel_init,failheight,u32,
 msgdata,channel_init,local_funding_locked,bool,
 msgdata,channel_init,remote_funding_locked,bool,
 msgdata,channel_init,funding_short_id,short_channel_id,
@@ -97,6 +98,7 @@ msgdata,channel_fulfill_htlc,fulfilled_htlc,fulfilled_htlc,
 # Main daemon says HTLC failed
 msgtype,channel_fail_htlc,1006
 msgdata,channel_fail_htlc,failed_htlc,failed_htlc,
+msgdata,channel_fail_htlc,failheight,u32,
 
 # When we receive funding_locked.
 msgtype,channel_got_funding_locked,1019

channeld/channeld.c

@@ -883,7 +883,8 @@ static u8 *make_failmsg(const tal_t *ctx,
 			const struct htlc *htlc,
 			enum onion_type failcode,
 			const struct short_channel_id *scid,
-			const struct sha256 *sha256)
+			const struct sha256 *sha256,
+			u32 failheight)
 {
 	u8 *msg, *channel_update = NULL;
 	u32 cltv_expiry = abs_locktime_to_blocks(&htlc->expiry);
@@ -940,10 +941,12 @@ static u8 *make_failmsg(const tal_t *ctx,
 		msg = towire_expiry_too_far(ctx);
 		goto done;
 	case WIRE_INCORRECT_OR_UNKNOWN_PAYMENT_DETAILS:
+		assert(failheight);
 		msg = towire_incorrect_or_unknown_payment_details(
 		    ctx, htlc->amount);
 		goto done;
 	case WIRE_FINAL_EXPIRY_TOO_SOON:
+		assert(failheight);
 		msg = towire_final_expiry_too_soon(ctx);
 		goto done;
 	case WIRE_FINAL_INCORRECT_CLTV_EXPIRY:
@@ -1915,7 +1918,8 @@ static void send_fail_or_fulfill(struct peer *peer, const struct htlc *h)
 			/* Local failure, make a message. */
 			u8 *failmsg = make_failmsg(tmpctx, peer, h, h->failcode,
 						   h->failed_scid,
-						   &h->next_onion_sha);
+						   &h->next_onion_sha,
+						   h->failblock);
 			onion = create_onionreply(tmpctx, h->shared_secret,
 						  failmsg);
 		} else /* Remote failure, just forward. */
@@ -2695,8 +2699,9 @@ static void handle_fail(struct peer *peer, const u8 *inmsg)
 	struct failed_htlc *failed_htlc;
 	enum channel_remove_err e;
 	struct htlc *h;
+	u32 failheight;
 
-	if (!fromwire_channel_fail_htlc(inmsg, inmsg, &failed_htlc))
+	if (!fromwire_channel_fail_htlc(inmsg, inmsg, &failed_htlc, &failheight))
 		master_badmsg(WIRE_CHANNEL_FAIL_HTLC, inmsg);
 
 	e = channel_fail_htlc(peer->channel, REMOTE, failed_htlc->id, &h);
@@ -2705,6 +2710,7 @@ static void handle_fail(struct peer *peer, const u8 *inmsg)
 		h->failcode = failed_htlc->failcode;
 		h->fail = tal_steal(h, failed_htlc->failreason);
 		h->failed_scid = tal_steal(h, failed_htlc->scid);
+		h->failblock = failheight;
 		send_fail_or_fulfill(peer, h);
 		start_commit_timer(peer);
 		return;
@@ -2855,7 +2861,7 @@ static void init_channel(struct peer *peer)
 	u8 *funding_signed;
 	const u8 *msg;
 	u32 feerate_per_kw[NUM_SIDES];
-	u32 minimum_depth;
+	u32 minimum_depth, failheight;
 	struct secret last_remote_per_commit_secret;
 	secp256k1_ecdsa_signature *remote_ann_node_sig;
 	secp256k1_ecdsa_signature *remote_ann_bitcoin_sig;
@@ -2901,6 +2907,7 @@ static void init_channel(struct peer *peer)
 				   &fulfilled_sides,
 				   &failed,
 				   &failed_sides,
+				   &failheight,
 				   &peer->funding_locked[LOCAL],
 				   &peer->funding_locked[REMOTE],
 				   &peer->short_channel_ids[LOCAL],
@@ -2978,7 +2985,7 @@ static void init_channel(struct peer *peer)
 				 fulfilled, fulfilled_sides,
 				 cast_const2(const struct failed_htlc **,
 					     failed),
-				 failed_sides))
+				 failed_sides, failheight))
 		status_failed(STATUS_FAIL_INTERNAL_ERROR,
 			      "Could not restore HTLCs");
 

channeld/channeld_htlc.h

@@ -40,6 +40,8 @@ struct htlc {
 	enum onion_type failcode;
 	/* If failcode & UPDATE, this is channel which failed. Otherwise NULL. */
 	const struct short_channel_id *failed_scid;
+	/* Block height it failed at */
+	u32 failblock;
 };
 
 static inline bool htlc_has(const struct htlc *h, int flag)

channeld/full_channel.c

@@ -1133,7 +1133,8 @@ bool channel_force_htlcs(struct channel *channel,
 			 const struct fulfilled_htlc *fulfilled,
 			 const enum side *fulfilled_sides,
 			 const struct failed_htlc **failed,
-			 const enum side *failed_sides)
+			 const enum side *failed_sides,
+			 u32 failheight)
 {
 	size_t i;
 	struct htlc *htlc;
@@ -1259,6 +1260,10 @@ bool channel_force_htlcs(struct channel *channel,
 			return false;
 		}
 		htlc->failcode = failed[i]->failcode;
+		/* We assume they all failed at the same height, which is
+		 * not necessarily true in case of restart.  But it's only
+		 * a hint. */
+		htlc->failblock = failheight;
 		if (failed[i]->failreason)
 			htlc->fail = tal_dup_arr(htlc, u8,
 						 failed[i]->failreason,

channeld/full_channel.h

@@ -236,6 +236,7 @@ size_t num_channel_htlcs(const struct channel *channel);
  * @fulfilled_sides: sides for ids in @fulfilled
  * @failed: htlcs of those which are failed
  * @failed_sides: sides for ids in @failed
+ * @failheight: block number which htlcs failed at.
  *
  * This is used for restoring a channel state.
  */
@@ -245,7 +246,8 @@ bool channel_force_htlcs(struct channel *channel,
 			 const struct fulfilled_htlc *fulfilled,
 			 const enum side *fulfilled_sides,
 			 const struct failed_htlc **failed,
-			 const enum side *failed_sides);
+			 const enum side *failed_sides,
+			 u32 failheight);
 
 /**
  * dump_htlcs: debugging dump of all HTLCs

devtools/mkcommit.c

@@ -357,7 +357,8 @@ int main(int argc, char *argv[])
 				   &funding_localkey, &funding_remotekey,
 				   fee_payer);
 
-	if (!channel_force_htlcs(channel, htlcs, hstates, NULL, NULL, NULL, NULL))
+	if (!channel_force_htlcs(channel, htlcs, hstates, NULL, NULL, NULL, NULL,
+				 0))
 		errx(1, "Cannot add HTLCs");
 
 	u8 *funding_wscript = bitcoin_redeem_2of2(NULL,

lightningd/channel_control.c

@@ -410,6 +410,9 @@ void peer_start_channeld(struct channel *channel,
 				      htlcs, htlc_states,
 				      fulfilled_htlcs, fulfilled_sides,
 				      failed_htlcs, failed_sides,
+				      /* This is an approximation, but failing
+				       * on restart is a corner case */
+				      get_block_height(ld->topology),
 				      channel->scid != NULL,
 				      channel->remote_funding_locked,
 				      &scid,

lightningd/peer_htlcs.c

@@ -124,7 +124,8 @@ static void fail_in_htlc(struct htlc_in *hin,
 	else
 		failed_htlc.scid = NULL;
 	subd_send_msg(hin->key.channel->owner,
-		      take(towire_channel_fail_htlc(NULL, &failed_htlc)));
+		      take(towire_channel_fail_htlc(NULL, &failed_htlc,
+						    get_block_height(hin->key.channel->owner->ld->topology))));
 }
 
 /* This is used for cases where we can immediately fail the HTLC. */

wallet/test/run-wallet.c

@@ -541,7 +541,7 @@ u8 *towire_channel_dev_memleak(const tal_t *ctx UNNEEDED)
 u8 *towire_channel_dev_reenable_commit(const tal_t *ctx UNNEEDED)
 { fprintf(stderr, "towire_channel_dev_reenable_commit called!\n"); abort(); }
 /* Generated stub for towire_channel_fail_htlc */
-u8 *towire_channel_fail_htlc(const tal_t *ctx UNNEEDED, const struct failed_htlc *failed_htlc UNNEEDED)
+u8 *towire_channel_fail_htlc(const tal_t *ctx UNNEEDED, const struct failed_htlc *failed_htlc UNNEEDED, u32 failheight UNUSED)
 { fprintf(stderr, "towire_channel_fail_htlc called!\n"); abort(); }
 /* Generated stub for towire_channel_fulfill_htlc */
 u8 *towire_channel_fulfill_htlc(const tal_t *ctx UNNEEDED, const struct fulfilled_htlc *fulfilled_htlc UNNEEDED)