lightningd: use explicit accessor to get channel_update for errors.

We want this later, so do the prep work now.

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

lightningd/channel.h

@@ -788,7 +788,10 @@ void channel_set_billboard(struct channel *channel, bool perm,
 struct htlc_in *channel_has_htlc_in(struct channel *channel);
 struct htlc_out *channel_has_htlc_out(struct channel *channel);
 
-const u8 *get_channel_update(struct channel *channel);
+const u8 *channel_update_for_error(const tal_t *ctx,
+				   struct channel *channel);
 
 struct amount_msat htlc_max_possible_send(const struct channel *channel);
+
+
 #endif /* LIGHTNING_LIGHTNINGD_CHANNEL_H */

lightningd/gossip_control.c

@@ -162,15 +162,20 @@ static void handle_local_channel_update(struct lightningd *ld, const u8 *msg)
 	channel_replace_update(channel, take(update));
 }
 
-const u8 *get_channel_update(struct channel *channel)
+const u8 *channel_update_for_error(const tal_t *ctx,
+				   struct channel *channel)
 {
+	if (!channel->channel_update)
+		return NULL;
+
 	/* Tell gossipd we're using it (if shutting down, might be NULL) */
-	if (channel->channel_update && channel->peer->ld->gossip) {
+	if (channel->peer->ld->gossip && channel->scid) {
 		subd_send_msg(channel->peer->ld->gossip,
 			      take(towire_gossipd_used_local_channel_update
 				   (NULL, channel->scid)));
 	}
-	return channel->channel_update;
+
+	return tal_dup_talarr(ctx, u8, channel->channel_update);
 }
 
 static void set_channel_remote_update(struct lightningd *ld,

lightningd/peer_htlcs.c

@@ -491,7 +491,8 @@ static void destroy_hout_subd_died(struct htlc_out *hout)
 		  hout->key.id);
 
 	hout->failmsg = towire_temporary_channel_failure(hout,
-							 get_channel_update(hout->key.channel));
+							 channel_update_for_error(tmpctx,
+										  hout->key.channel));
 
 	/* Assign a temporary state (we're about to free it!) so checks
 	 * are happy that it has a failure message */
@@ -529,7 +530,7 @@ static void rcvd_htlc_reply(struct subd *subd, const u8 *msg, const int *fds UNU
 	if (tal_count(failmsg)) {
 		/* It's our job to append the channel_update */
 		if (fromwire_peektype(failmsg) & UPDATE) {
-			const u8 *update = get_channel_update(hout->key.channel);
+			const u8 *update = channel_update_for_error(tmpctx, hout->key.channel);
 			towire(&failmsg, update, tal_bytelen(update));
 		}
 		hout->failmsg = tal_steal(hout, failmsg);
@@ -626,7 +627,7 @@ const u8 *send_htlc_out(const tal_t *ctx,
 		log_info(out->log, "Attempt to send HTLC but unowned (%s)",
 			 channel_state_name(out));
 		return towire_temporary_channel_failure(ctx,
-							get_channel_update(out));
+							channel_update_for_error(tmpctx, out));
 	}
 
 	if (!topology_synced(out->peer->ld->topology)) {
@@ -749,7 +750,8 @@ static void forward_htlc(struct htlc_in *hin,
 					 next->old_feerate_base,
 					 next->old_feerate_ppm)) {
 			failmsg = towire_fee_insufficient(tmpctx, hin->msat,
-							  get_channel_update(next));
+							  channel_update_for_error(tmpctx,
+										   next));
 			goto fail;
 		}
 		log_info(hin->key.channel->log,
@@ -763,7 +765,7 @@ static void forward_htlc(struct htlc_in *hin,
 		    || amount_msat_less(amt_to_forward, next->old_htlc_minimum_msat)
 		    || amount_msat_greater(amt_to_forward, next->old_htlc_maximum_msat)) {
 			failmsg = towire_temporary_channel_failure(tmpctx,
-								   get_channel_update(next));
+								   channel_update_for_error(tmpctx, next));
 			goto fail;
 		}
 		log_info(hin->key.channel->log,
@@ -773,7 +775,7 @@ static void forward_htlc(struct htlc_in *hin,
 	if (!check_cltv(hin, cltv_expiry, outgoing_cltv_value,
 			ld->config.cltv_expiry_delta)) {
 		failmsg = towire_incorrect_cltv_expiry(tmpctx, cltv_expiry,
-						       get_channel_update(next));
+						       channel_update_for_error(tmpctx, next));
 		goto fail;
 	}
 
@@ -792,7 +794,7 @@ static void forward_htlc(struct htlc_in *hin,
 			  outgoing_cltv_value,
 			  get_block_height(ld->topology));
 		failmsg = towire_expiry_too_soon(tmpctx,
-						 get_channel_update(next));
+						 channel_update_for_error(tmpctx, next));
 		goto fail;
 	}
 

wallet/test/run-wallet.c

@@ -88,6 +88,10 @@ void channel_unsaved_close_conn(struct channel *channel UNNEEDED, const char *wh
 /* Generated stub for channel_update_feerates */
 void channel_update_feerates(struct lightningd *ld UNNEEDED, const struct channel *channel UNNEEDED)
 { fprintf(stderr, "channel_update_feerates called!\n"); abort(); }
+/* Generated stub for channel_update_for_error */
+const u8 *channel_update_for_error(const tal_t *ctx UNNEEDED,
+				   struct channel *channel UNNEEDED)
+{ fprintf(stderr, "channel_update_for_error called!\n"); abort(); }
 /* Generated stub for channel_update_reserve */
 void channel_update_reserve(struct channel *channel UNNEEDED,
 			    struct channel_config *their_config UNNEEDED,
@@ -296,9 +300,6 @@ bool fromwire_openingd_dev_memleak_reply(const void *p UNNEEDED, bool *leak UNNE
 /* Generated stub for get_block_height */
 u32 get_block_height(const struct chain_topology *topo UNNEEDED)
 { fprintf(stderr, "get_block_height called!\n"); abort(); }
-/* Generated stub for get_channel_update */
-const u8 *get_channel_update(struct channel *channel UNNEEDED)
-{ fprintf(stderr, "get_channel_update called!\n"); abort(); }
 /* Generated stub for hsmd_wire_name */
 const char *hsmd_wire_name(int e UNNEEDED)
 { fprintf(stderr, "hsmd_wire_name called!\n"); abort(); }