channeld, lightningd: allow blinded payments with !EXPERIMENTAL_FEATURES.

Gate it (where necessary) by the route-blinding feature bit.

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

channeld/channeld.c

@@ -690,31 +690,20 @@ static void handle_peer_add_htlc(struct peer *peer, const u8 *msg)
 	u8 onion_routing_packet[TOTAL_PACKET_SIZE(ROUTING_INFO_SIZE)];
 	enum channel_add_err add_err;
 	struct htlc *htlc;
-#if EXPERIMENTAL_FEATURES
 	struct tlv_update_add_tlvs *tlvs;
-#endif
-	struct pubkey *blinding = NULL;
 
-	if (!fromwire_update_add_htlc
-#if EXPERIMENTAL_FEATURES
-	    (msg, msg, &channel_id, &id, &amount,
-	     &payment_hash, &cltv_expiry,
-	     onion_routing_packet, &tlvs)
-#else
-	    (msg, &channel_id, &id, &amount,
-	     &payment_hash, &cltv_expiry,
-	     onion_routing_packet)
-#endif
-		)
+	if (!fromwire_update_add_htlc(msg, msg, &channel_id, &id, &amount,
+				      &payment_hash, &cltv_expiry,
+				      onion_routing_packet, &tlvs)
+	    /* This is an *even* field: don't send if we didn't understand */
+	    || (tlvs->blinding && !feature_offered(peer->our_features->bits[INIT_FEATURE],
+						   OPT_ROUTE_BLINDING))) {
 		peer_failed_warn(peer->pps, &peer->channel_id,
 				 "Bad peer_add_htlc %s", tal_hex(msg, msg));
-
-#if EXPERIMENTAL_FEATURES
-	blinding = tlvs->blinding;
-#endif
+	}
 	add_err = channel_add_htlc(peer->channel, REMOTE, id, amount,
 				   cltv_expiry, &payment_hash,
-				   onion_routing_packet, blinding, &htlc, NULL,
+				   onion_routing_packet, tlvs->blinding, &htlc, NULL,
 				   /* We don't immediately fail incoming htlcs,
 				    * instead we wait and fail them after
 				    * they've been committed */
@@ -2431,7 +2420,6 @@ static void resend_commitment(struct peer *peer, struct changed_htlc *last)
 					 last[i].id);
 
 		if (h->state == SENT_ADD_COMMIT) {
-#if EXPERIMENTAL_FEATURES
 			struct tlv_update_add_tlvs *tlvs;
 			if (h->blinding) {
 				tlvs = tlv_update_add_tlvs_new(tmpctx);
@@ -2439,17 +2427,12 @@ static void resend_commitment(struct peer *peer, struct changed_htlc *last)
 							 h->blinding);
 			} else
 				tlvs = NULL;
-#endif
 			msg = towire_update_add_htlc(NULL, &peer->channel_id,
 						     h->id, h->amount,
 						     &h->rhash,
 						     abs_locktime_to_blocks(
 							     &h->expiry),
-						     h->routing
-#if EXPERIMENTAL_FEATURES
-						     , tlvs
-#endif
-				);
+						     h->routing, tlvs);
 			peer_write(peer->pps, take(msg));
 		}
 	}
@@ -3315,6 +3298,7 @@ static void handle_offer_htlc(struct peer *peer, const u8 *inmsg)
 	const char *failstr;
 	struct amount_sat htlc_fee;
 	struct pubkey *blinding;
+	struct tlv_update_add_tlvs *tlvs;
 
 	if (!peer->channel_ready[LOCAL] || !peer->channel_ready[REMOTE])
 		status_failed(STATUS_FAIL_MASTER_IO,
@@ -3325,14 +3309,11 @@ static void handle_offer_htlc(struct peer *peer, const u8 *inmsg)
 					 onion_routing_packet, &blinding))
 		master_badmsg(WIRE_CHANNELD_OFFER_HTLC, inmsg);
 
-#if EXPERIMENTAL_FEATURES
-	struct tlv_update_add_tlvs *tlvs;
 	if (blinding) {
 		tlvs = tlv_update_add_tlvs_new(tmpctx);
 		tlvs->blinding = tal_dup(tlvs, struct pubkey, blinding);
 	} else
 		tlvs = NULL;
-#endif
 
 	e = channel_add_htlc(peer->channel, LOCAL, peer->htlc_id,
 			     amount, cltv_expiry, &payment_hash,
@@ -3350,11 +3331,7 @@ static void handle_offer_htlc(struct peer *peer, const u8 *inmsg)
 		msg = towire_update_add_htlc(NULL, &peer->channel_id,
 					     peer->htlc_id, amount,
 					     &payment_hash, cltv_expiry,
-					     onion_routing_packet
-#if EXPERIMENTAL_FEATURES
-					     , tlvs
-#endif
-			);
+					     onion_routing_packet, tlvs);
 		peer_write(peer->pps, take(msg));
 		start_commit_timer(peer);
 		/* Tell the master. */

lightningd/peer_htlcs.c

@@ -149,7 +149,6 @@ static void fail_in_htlc(struct htlc_in *hin,
 	htlc_in_update_state(hin->key.channel, hin, SENT_REMOVE_HTLC);
 	htlc_in_check(hin, __func__);
 
-#if EXPERIMENTAL_FEATURES
 	/* BOLT-route-blinding #4:
 	 * - If `blinding_point` is set in the incoming `update_add_htlc`:
 	 *    - MUST return `invalid_onion_blinding` on any error, including
@@ -159,7 +158,6 @@ static void fail_in_htlc(struct htlc_in *hin,
 		failed_htlc = mk_failed_htlc_badonion(tmpctx, hin,
 						      WIRE_INVALID_ONION_BLINDING);
 	} else
-#endif
 		failed_htlc = mk_failed_htlc(tmpctx, hin, hin->failonion);
 
 	bool we_filled = false;
@@ -1149,7 +1147,6 @@ static bool ecdh_maybe_blinding(const struct pubkey *ephemeral_key,
 {
 	struct pubkey point = *ephemeral_key;
 
-#if EXPERIMENTAL_FEATURES
 	if (blinding) {
 		struct secret hmac;
 		struct secret blinding_ss;
@@ -1167,7 +1164,6 @@ static bool ecdh_maybe_blinding(const struct pubkey *ephemeral_key,
 			return false;
 		}
 	}
-#endif /* EXPERIMENTAL_FEATURES */
 	ecdh(&point, ss);
 	return true;
 }
@@ -1234,6 +1230,10 @@ static bool peer_accepted_htlc(const tal_t *ctx,
 	struct onionpacket *op;
 	struct lightningd *ld = channel->peer->ld;
 	struct htlc_accepted_hook_payload *hook_payload;
+	const bool opt_blinding
+		= feature_offered(ld->our_features->bits[INIT_FEATURE],
+				  OPT_ROUTE_BLINDING);
+
 
 	*failmsg = NULL;
 	*badonion = 0;
@@ -1335,9 +1335,9 @@ static bool peer_accepted_htlc(const tal_t *ctx,
 	hook_payload->channel = channel;
 	hook_payload->next_onion = serialize_onionpacket(hook_payload, rs->next);
 
-#if EXPERIMENTAL_FEATURES
 	/* We could have blinding from hin or from inside onion. */
-	if (hook_payload->payload && hook_payload->payload->blinding) {
+	if (opt_blinding
+	    && hook_payload->payload && hook_payload->payload->blinding) {
 		struct sha256 sha;
 		blinding_hash_e_and_ss(hook_payload->payload->blinding,
 				       &hook_payload->payload->blinding_ss,
@@ -1346,7 +1346,6 @@ static bool peer_accepted_htlc(const tal_t *ctx,
 		blinding_next_pubkey(hook_payload->payload->blinding, &sha,
 				     hook_payload->next_blinding);
 	} else
-#endif
 		hook_payload->next_blinding = NULL;
 
 	/* The scid is merely used to indicate the next peer, it is not
@@ -1365,13 +1364,11 @@ static bool peer_accepted_htlc(const tal_t *ctx,
 	return true;
 
 fail:
-#if EXPERIMENTAL_FEATURES
 	/* In a blinded path, *all* failures are "invalid_onion_blinding" */
 	if (hin->blinding) {
 		*failmsg = tal_free(*failmsg);
 		*badonion = WIRE_INVALID_ONION_BLINDING;
 	}
-#endif
 	return false;
 }
 

wire/peer_wire.csv

@@ -214,6 +214,9 @@ msgdata,update_add_htlc,amount_msat,u64,
 msgdata,update_add_htlc,payment_hash,sha256,
 msgdata,update_add_htlc,cltv_expiry,u32,
 msgdata,update_add_htlc,onion_routing_packet,byte,1366
+msgdata,update_add_htlc,tlvs,update_add_tlvs,
+tlvtype,update_add_tlvs,blinding,2
+tlvdata,update_add_tlvs,blinding,blinding,point,
 msgtype,update_fulfill_htlc,130
 msgdata,update_fulfill_htlc,channel_id,channel_id,
 msgdata,update_fulfill_htlc,id,u64,

wire/test/run-peer-wire.c

@@ -680,37 +680,21 @@ static void *towire_struct_update_add_htlc(const tal_t *ctx,
 				      s->amount_msat,
 				      &s->payment_hash,
 				      s->expiry,
-				      s->onion_routing_packet
-#if EXPERIMENTAL_FEATURES
-				      ,NULL
-#endif
-		);
+				      s->onion_routing_packet, NULL);
 }
 
 static struct msg_update_add_htlc *fromwire_struct_update_add_htlc(const tal_t *ctx, const void *p)
 {
 	struct msg_update_add_htlc *s = tal(ctx, struct msg_update_add_htlc);
 
-	if (fromwire_update_add_htlc
-#if EXPERIMENTAL_FEATURES
-				    (s,	p,
+	if (fromwire_update_add_htlc(s, p,
 				     &s->channel_id,
 				     &s->id,
 				     &s->amount_msat,
 				     &s->payment_hash,
 				     &s->expiry,
 				     s->onion_routing_packet,
-				     &s->tlvs
-#else
-				    (p,
-				     &s->channel_id,
-				     &s->id,
-				     &s->amount_msat,
-				     &s->payment_hash,
-				     &s->expiry,
-				     s->onion_routing_packet
-#endif
-		    ))
+				     &s->tlvs))
 		return s;
 	return tal_free(s);
 }