Onion TLV support (EXPERIMENTAL_FEATURE)

common/features.c

@@ -8,6 +8,9 @@ static const u32 our_features[] = {
 	OPTIONAL_FEATURE(OPT_DATA_LOSS_PROTECT),
 	OPTIONAL_FEATURE(OPT_UPFRONT_SHUTDOWN_SCRIPT),
 	OPTIONAL_FEATURE(OPT_GOSSIP_QUERIES),
+#if EXPERIMENTAL_FEATURES
+	OPTIONAL_FEATURE(OPT_VAR_ONION),
+#endif
 	OPTIONAL_FEATURE(OPT_GOSSIP_QUERIES_EX),
 	OPTIONAL_FEATURE(OPT_STATIC_REMOTEKEY),
 };

common/sphinx.c

@@ -134,9 +134,10 @@ void sphinx_add_raw_hop(struct sphinx_path *path, const struct pubkey *pubkey,
 	assert(sphinx_path_payloads_size(path) <= ROUTING_INFO_SIZE);
 }
 
-void sphinx_add_v0_hop(struct sphinx_path *path, const struct pubkey *pubkey,
-		       const struct short_channel_id *scid,
-		       struct amount_msat forward, u32 outgoing_cltv)
+static void sphinx_add_v0_hop(struct sphinx_path *path,
+			      const struct pubkey *pubkey,
+			      const struct short_channel_id *scid,
+			      struct amount_msat forward, u32 outgoing_cltv)
 {
 	const u8 padding[] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 			      0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
@@ -149,6 +150,80 @@ void sphinx_add_v0_hop(struct sphinx_path *path, const struct pubkey *pubkey,
 	sphinx_add_raw_hop(path, pubkey, 0, buf);
 }
 
+static void sphinx_add_tlv_hop(struct sphinx_path *path,
+			       const struct pubkey *pubkey,
+			       const struct tlv_tlv_payload *tlv)
+{
+	u8 *tlvs = tal_arr(path, u8, 0);
+	towire_tlvs(&tlvs, tlvs_tlv_payload, TLVS_TLV_PAYLOAD_ARRAY_SIZE, tlv);
+	sphinx_add_raw_hop(path, pubkey, tal_bytelen(tlvs), tlvs);
+}
+
+void sphinx_add_nonfinal_hop(struct sphinx_path *path,
+			     const struct pubkey *pubkey,
+			     bool use_tlv,
+			     const struct short_channel_id *scid,
+			     struct amount_msat forward,
+			     u32 outgoing_cltv)
+{
+	if (use_tlv) {
+		struct tlv_tlv_payload *tlv = tlv_tlv_payload_new(tmpctx);
+		struct tlv_tlv_payload_amt_to_forward tlv_amt;
+		struct tlv_tlv_payload_outgoing_cltv_value tlv_cltv;
+		struct tlv_tlv_payload_short_channel_id tlv_scid;
+
+		/* BOLT #4:
+		 *
+		 * The writer:
+		 *  - MUST include `amt_to_forward` and `outgoing_cltv_value`
+		 *    for every node.
+		 *  - MUST include `short_channel_id` for every non-final node.
+		 */
+		tlv_amt.amt_to_forward = forward.millisatoshis; /* Raw: TLV convert */
+		tlv_cltv.outgoing_cltv_value = outgoing_cltv;
+		tlv_scid.short_channel_id = *scid;
+		tlv->amt_to_forward = &tlv_amt;
+		tlv->outgoing_cltv_value = &tlv_cltv;
+		tlv->short_channel_id = &tlv_scid;
+
+		sphinx_add_tlv_hop(path, pubkey, tlv);
+	} else {
+		sphinx_add_v0_hop(path, pubkey, scid, forward, outgoing_cltv);
+	}
+}
+
+void sphinx_add_final_hop(struct sphinx_path *path,
+			  const struct pubkey *pubkey,
+			  bool use_tlv,
+			  struct amount_msat forward,
+			  u32 outgoing_cltv)
+{
+	if (use_tlv) {
+		struct tlv_tlv_payload *tlv = tlv_tlv_payload_new(tmpctx);
+		struct tlv_tlv_payload_amt_to_forward tlv_amt;
+		struct tlv_tlv_payload_outgoing_cltv_value tlv_cltv;
+
+		/* BOLT #4:
+		 *
+		 * The writer:
+		 *  - MUST include `amt_to_forward` and `outgoing_cltv_value`
+		 *    for every node.
+		 *...
+		 *  - MUST NOT include `short_channel_id` for the final node.
+		 */
+		tlv_amt.amt_to_forward = forward.millisatoshis; /* Raw: TLV convert */
+		tlv_cltv.outgoing_cltv_value = outgoing_cltv;
+		tlv->amt_to_forward = &tlv_amt;
+		tlv->outgoing_cltv_value = &tlv_cltv;
+
+		sphinx_add_tlv_hop(path, pubkey, tlv);
+	} else {
+		static struct short_channel_id all_zero_scid;
+		sphinx_add_v0_hop(path, pubkey, &all_zero_scid,
+				  forward, outgoing_cltv);
+	}
+}
+
 /* Small helper to append data to a buffer and update the position
  * into the buffer
  */
@@ -426,7 +501,7 @@ static struct hop_params *generate_hop_params(
 	return params;
 }
 
-static void deserialize_hop_data(struct hop_data *data, const u8 *src)
+static void deserialize_hop_data(struct hop_data_legacy *data, const u8 *src)
 {
 	const u8 *cursor = src;
 	size_t max = FRAME_SIZE;
@@ -477,16 +552,31 @@ static void sphinx_parse_payload(struct route_step *step, const u8 *src)
 	}
 #endif
 
-	/* Legacy hop_data support */
+	/* BOLT #4:
+	 *
+	 * The `length` field determines both the length and the format of the
+	 * `hop_payload` field; the following formats are defined:
+	 *
+	 * - Legacy `hop_data` format, identified by a single `0x00` byte for
+	 *   length. In this case the `hop_payload_length` is defined to be 32
+	 *   bytes.
+	 *
+	 * - `tlv_payload` format, identified by any length over `1`. In this
+	 *   case the `hop_payload_length` is equal to the numeric value of
+	 *   `length`.
+	 */
 	if (src[0] == 0x00) {
 		vsize = 1;
 		raw_size = 32;
 		hop_size = FRAME_SIZE;
 		step->type = SPHINX_V0_PAYLOAD;
-	} else {
+	} else if (src[0] > 1) {
 		vsize = bigsize_get(src, 3, &raw_size);
 		hop_size = raw_size + vsize + HMAC_SIZE;
 		step->type = SPHINX_TLV_PAYLOAD;
+	} else {
+		step->type = SPHINX_INVALID_PAYLOAD;
+		return;
 	}
 
 	/* Copy common pieces over */
@@ -497,6 +587,18 @@ static void sphinx_parse_payload(struct route_step *step, const u8 *src)
 	 * later. */
 	if (step->type == SPHINX_V0_PAYLOAD)
 		deserialize_hop_data(&step->payload.v0, src);
+	else if (step->type == SPHINX_TLV_PAYLOAD) {
+		const u8 *tlv = step->raw_payload;
+		size_t max = tal_bytelen(tlv);
+		step->payload.tlv = tlv_tlv_payload_new(step);
+		if (!fromwire_tlvs(&tlv, &max, tlvs_tlv_payload,
+				   TLVS_TLV_PAYLOAD_ARRAY_SIZE,
+				   step->payload.tlv)) {
+			/* FIXME: record offset of violation for error! */
+			step->type = SPHINX_INVALID_PAYLOAD;
+			return;
+		}
+	}
 }
 
 struct onionpacket *create_onionpacket(
@@ -781,3 +883,74 @@ struct onionreply *unwrap_onionreply(const tal_t *ctx,
 	return oreply;
 
 }
+
+/**
+ * Helper to extract fields from ONION_END.
+ */
+bool route_step_decode_end(const struct route_step *rs,
+			   struct amount_msat *amt_forward,
+			   u32 *outgoing_cltv)
+{
+	assert(rs->nextcase == ONION_END);
+
+	switch (rs->type) {
+	case SPHINX_V0_PAYLOAD:
+		*amt_forward = rs->payload.v0.amt_forward;
+		*outgoing_cltv = rs->payload.v0.outgoing_cltv;
+		return true;
+	case SPHINX_TLV_PAYLOAD:
+		if (!rs->payload.tlv->amt_to_forward)
+			return false;
+		if (!rs->payload.tlv->outgoing_cltv_value)
+			return false;
+		amt_forward->millisatoshis /* Raw: tu64 -> millisatoshis */
+			= rs->payload.tlv->amt_to_forward->amt_to_forward;
+		*outgoing_cltv = rs->payload.tlv->outgoing_cltv_value->outgoing_cltv_value;
+		return true;
+	case SPHINX_INVALID_PAYLOAD:
+		return false;
+
+	/* This should probably be removed, as it's just for testing */
+	case SPHINX_RAW_PAYLOAD:
+		abort();
+	}
+	abort();
+}
+
+/**
+ * Helper to extract fields from ONION_FORWARD.
+ */
+bool route_step_decode_forward(const struct route_step *rs,
+			       struct amount_msat *amt_forward,
+			       u32 *outgoing_cltv,
+			       struct short_channel_id *scid)
+{
+	assert(rs->nextcase == ONION_FORWARD);
+
+	switch (rs->type) {
+	case SPHINX_V0_PAYLOAD:
+		*amt_forward = rs->payload.v0.amt_forward;
+		*outgoing_cltv = rs->payload.v0.outgoing_cltv;
+		*scid = rs->payload.v0.channel_id;
+		return true;
+	case SPHINX_TLV_PAYLOAD:
+		if (!rs->payload.tlv->amt_to_forward)
+			return false;
+		amt_forward->millisatoshis /* Raw: tu64 -> millisatoshis */
+			= rs->payload.tlv->amt_to_forward->amt_to_forward;
+		if (!rs->payload.tlv->outgoing_cltv_value)
+			return false;
+		*outgoing_cltv = rs->payload.tlv->outgoing_cltv_value->outgoing_cltv_value;
+		if (!rs->payload.tlv->short_channel_id)
+			return false;
+		*scid = rs->payload.tlv->short_channel_id->short_channel_id;
+		return true;
+	case SPHINX_INVALID_PAYLOAD:
+		return false;
+
+	/* This should probably be removed, as it's just for testing */
+	case SPHINX_RAW_PAYLOAD:
+		abort();
+	}
+	abort();
+}

common/sphinx.h

@@ -61,7 +61,7 @@ struct sphinx_path;
  *    * [`u32`:`outgoing_cltv_value`]
  *    * [`12*byte`:`padding`]
  */
-struct hop_data {
+struct hop_data_legacy {
 	u8 realm;
 	struct short_channel_id channel_id;
 	struct amount_msat amt_forward;
@@ -80,7 +80,8 @@ struct route_step {
 	struct onionpacket *next;
 	enum sphinx_payload_type type;
 	union {
-		struct hop_data v0;
+		struct hop_data_legacy v0;
+		struct tlv_tlv_payload *tlv;
 	} payload;
 	u8 *raw_payload;
 };
@@ -218,16 +219,43 @@ struct sphinx_path *sphinx_path_new_with_key(const tal_t *ctx,
 					     const u8 *associated_data,
 					     const struct secret *session_key);
 
-/**
- * Add a V0 (Realm 0) single frame hop to the path.
- */
-void sphinx_add_v0_hop(struct sphinx_path *path, const struct pubkey *pubkey,
-		       const struct short_channel_id *scid, struct amount_msat forward,
-		       u32 outgoing_cltv);
 /**
  * Add a raw payload hop to the path.
  */
 void sphinx_add_raw_hop(struct sphinx_path *path, const struct pubkey *pubkey,
 			enum sphinx_payload_type type, const u8 *payload);
 
+/**
+ * Add a non-final hop to the path.
+ */
+void sphinx_add_nonfinal_hop(struct sphinx_path *path,
+			     const struct pubkey *pubkey,
+			     bool use_tlv,
+			     const struct short_channel_id *scid,
+			     struct amount_msat forward,
+			     u32 outgoing_cltv);
+
+/**
+ * Add a final hop to the path.
+ */
+void sphinx_add_final_hop(struct sphinx_path *path,
+			  const struct pubkey *pubkey,
+			  bool use_tlv,
+			  struct amount_msat forward,
+			  u32 outgoing_cltv);
+
+/**
+ * Helper to extract fields from ONION_END.
+ */
+bool route_step_decode_end(const struct route_step *rs,
+			   struct amount_msat *amt_forward,
+			   u32 *outgoing_cltv);
+
+/**
+ * Helper to extract fields from ONION_FORWARD.
+ */
+bool route_step_decode_forward(const struct route_step *rs,
+			       struct amount_msat *amt_forward,
+			       u32 *outgoing_cltv,
+			       struct short_channel_id *scid);
 #endif /* LIGHTNING_COMMON_SPHINX_H */

common/test/Makefile

@@ -11,6 +11,9 @@ $(COMMON_TEST_OBJS): $(COMMON_HEADERS) $(WIRE_HEADERS) $(COMMON_SRC)
 ALL_TEST_PROGRAMS += $(COMMON_TEST_PROGRAMS)
 ALL_OBJS += $(COMMON_TEST_PROGRAMS:=.o)
 
+# Sphinx test wants to decode TLVs.
+common/test/run-sphinx: wire/gen_onion_wire.o
+
 update-mocks: $(COMMON_TEST_SRC:%=update-mocks/%)
 
 check-units: $(COMMON_TEST_PROGRAMS:%=unittest/%)