sphinx: Cleanup sphinx onion construction, remove realm

The realm has lost significance, so let's unify this into the type.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

common/sphinx.c

@@ -45,7 +45,7 @@ struct keyset {
  * generation is payload agnostic. */
 struct sphinx_hop {
 	struct pubkey pubkey;
-	u8 realm;
+	enum sphinx_payload_type type;
 	const u8 *payload;
 	u8 hmac[HMAC_SIZE];
 };
@@ -101,7 +101,7 @@ static size_t sphinx_hop_size(const struct sphinx_hop *hop)
 
 	/* Backwards compatibility: realm 0 is the legacy hop_data format and
 	 * always has 65 bytes in size */
-	if (hop->realm == 0x00)
+	if (hop->type == SPHINX_V0_PAYLOAD)
 		return 65;
 
 	/* Since this uses the bigsize serialization format for variable
@@ -126,11 +126,11 @@ static size_t sphinx_path_payloads_size(const struct sphinx_path *path)
 }
 
 void sphinx_add_raw_hop(struct sphinx_path *path, const struct pubkey *pubkey,
-			u8 realm, const u8 *payload)
+			enum sphinx_payload_type type, const u8 *payload)
 {
 	struct sphinx_hop sp;
 	sp.payload = payload;
-	sp.realm = realm;
+	sp.type = type;
 	sp.pubkey = *pubkey;
 	tal_arr_expand(&path->hops, sp);
 	assert(sphinx_path_payloads_size(path) <= ROUTING_INFO_SIZE);
@@ -446,12 +446,12 @@ static bool sphinx_write_frame(u8 *dest, const struct sphinx_hop *hop)
 	int pos = 0;
 
 #if !EXPERIMENTAL_FEATURES
-	if (hop->realm != 0x00)
+	if (hop->type != SPHINX_V0_PAYLOAD)
 		return false;
 #endif
 
 	/* Backwards compatibility for the legacy hop_data format. */
-	if (hop->realm == 0x00)
+	if (hop->type == SPHINX_V0_PAYLOAD)
 		dest[pos++] = 0x00;
 	else
 		pos += varint_put(dest+pos, raw_size);
@@ -483,10 +483,11 @@ static void sphinx_parse_payload(struct route_step *step, const u8 *src)
 		vsize = 1;
 		raw_size = 32;
 		hop_size = FRAME_SIZE;
-		step->realm = src[0];
+		step->type = SPHINX_V0_PAYLOAD;
 	} else {
 		vsize = varint_get(src, 3, &raw_size);
 		hop_size = raw_size + vsize + HMAC_SIZE;
+		step->type = SPHINX_TLV_PAYLOAD;
 	}
 
 	/* Copy common pieces over */
@@ -495,12 +496,8 @@ static void sphinx_parse_payload(struct route_step *step, const u8 *src)
 
 	/* And now try to parse whatever the payload contains so we can use it
 	 * later. */
-	if (step->realm == SPHINX_V0_PAYLOAD) {
-		step->type = SPHINX_V0_PAYLOAD;
+	if (step->type == SPHINX_V0_PAYLOAD)
 		deserialize_hop_data(&step->payload.v0, src);
-	} else {
-		step->type = SPHINX_RAW_PAYLOAD;
-	}
 }
 
 struct onionpacket *create_onionpacket(

common/sphinx.h

@@ -17,16 +17,9 @@
 #define HMAC_SIZE 32
 #define PUBKEY_SIZE 33
 #define FRAME_SIZE 65
-#define NUM_MAX_FRAMES 20
-#define ROUTING_INFO_SIZE (FRAME_SIZE * NUM_MAX_FRAMES)
+#define ROUTING_INFO_SIZE 1300
 #define TOTAL_PACKET_SIZE (VERSION_SIZE + PUBKEY_SIZE + HMAC_SIZE + ROUTING_INFO_SIZE)
 
-#if EXPERIMENTAL_FEATURES
-#define MAX_FRAMES_PER_HOP (1 << 4)
-#else
-#define MAX_FRAMES_PER_HOP 1
-#endif
-
 struct onionpacket {
 	/* Cleartext information */
 	u8 version;
@@ -93,6 +86,7 @@ struct hop_data {
 
 enum sphinx_payload_type {
 	SPHINX_V0_PAYLOAD = 0,
+	SPHINX_TLV_PAYLOAD = 1,
 	SPHINX_INVALID_PAYLOAD = 254,
 	SPHINX_RAW_PAYLOAD = 255,
 };
@@ -100,13 +94,11 @@ enum sphinx_payload_type {
 struct route_step {
 	enum route_next_case nextcase;
 	struct onionpacket *next;
-	u8 realm;
 	enum sphinx_payload_type type;
 	union {
 		struct hop_data v0;
 	} payload;
 	u8 *raw_payload;
-	u8 payload_frames;
 };
 
 /**
@@ -252,6 +244,6 @@ void sphinx_add_v0_hop(struct sphinx_path *path, const struct pubkey *pubkey,
  * Add a raw payload hop to the path.
  */
 void sphinx_add_raw_hop(struct sphinx_path *path, const struct pubkey *pubkey,
-			u8 realm, const u8 *payload);
+			enum sphinx_payload_type type, const u8 *payload);
 
 #endif /* LIGHTNING_COMMON_SPHINX_H */

devtools/onion.c

@@ -201,13 +201,13 @@ static void runtest(const char *filename)
 	bool valid;
 	char *buffer = grab_file(ctx, filename);
 	const jsmntok_t *toks, *session_key_tok, *associated_data_tok, *gentok,
-		*hopstok, *hop, *payloadtok, *pubkeytok, *realmtok, *oniontok, *decodetok;
+		*hopstok, *hop, *payloadtok, *pubkeytok, *typetok, *oniontok, *decodetok;
 	const u8 *associated_data, *session_key_raw, *payload, *serialized, *onion;
 	struct secret session_key, *shared_secrets;
 	struct pubkey pubkey;
 	struct sphinx_path *path;
 	size_t i;
-	int realm;
+	enum sphinx_payload_type type;
 	struct onionpacket *res;
 	struct route_step *step;
 	char *hexprivkey;
@@ -232,12 +232,16 @@ static void runtest(const char *filename)
 	hopstok = json_get_member(buffer, gentok, "hops");
 	json_for_each_arr(i, hop, hopstok) {
 		payloadtok = json_get_member(buffer, hop, "payload");
-		realmtok = json_get_member(buffer, hop, "realm");
+		typetok = json_get_member(buffer, hop, "type");
 		pubkeytok = json_get_member(buffer, hop, "pubkey");
 		payload = json_tok_bin_from_hex(ctx, buffer, payloadtok);
 		json_to_pubkey(buffer, pubkeytok, &pubkey);
-		json_to_int(buffer, realmtok, &realm);
-		sphinx_add_raw_hop(path, &pubkey, realm, payload);
+		if (!typetok || json_tok_streq(buffer, typetok, "legacy")) {
+			type = SPHINX_V0_PAYLOAD;
+		} else {
+			type = SPHINX_RAW_PAYLOAD;
+		}
+		sphinx_add_raw_hop(path, &pubkey, type, payload);
 	}
 	res = create_onionpacket(ctx, path, &shared_secrets);
 	serialized = serialize_onionpacket(ctx, res);
@@ -259,17 +263,6 @@ static void runtest(const char *filename)
 	}
 	printf("Generated onion: %s\n", tal_hex(ctx, serialized));
 
-	hopstok = json_get_member(buffer, gentok, "hops");
-	json_for_each_arr(i, hop, hopstok) {
-		payloadtok = json_get_member(buffer, hop, "payload");
-		realmtok = json_get_member(buffer, hop, "realm");
-		pubkeytok = json_get_member(buffer, hop, "pubkey");
-		payload = json_tok_bin_from_hex(ctx, buffer, payloadtok);
-		json_to_pubkey(buffer, pubkeytok, &pubkey);
-		json_to_int(buffer, realmtok, &realm);
-		sphinx_add_raw_hop(path, &pubkey, realm, payload);
-	}
-
 	decodetok = json_get_member(buffer, toks, "decode");
 
 	json_for_each_arr(i, hop, decodetok) {
@@ -279,7 +272,7 @@ static void runtest(const char *filename)
 		serialized = serialize_onionpacket(ctx, step->next);
 		if (!serialized)
 			errx(1, "Error serializing message.");
-		printf("  Realm: %d\n", step->realm);
+		printf("  Type: %d\n", step->type);
 		printf("  Payload: %s\n", tal_hex(ctx, step->raw_payload));
 		printf("  Next onion: %s\n", tal_hex(ctx, serialized));
 		printf("  Next HMAC: %s\n", tal_hexstr(ctx, step->next->mac, HMAC_SIZE));