Function parse_onionpacket

common/sphinx.c:196–230

}

struct onionpacket *parse_onionpacket(const tal_t *ctx,
				      const u8 *src,
				      const size_t srclen,
				      enum onion_wire *failcode)
{
	struct onionpacket *dest = tal(ctx, struct onionpacket);
	const u8 *cursor = src;
	size_t max = srclen;

	dest->version = fromwire_u8(&cursor, &max);
	if (dest->version != 0x00) {
		// FIXME add logging
		*failcode = WIRE_INVALID_ONION_VERSION;
		return tal_free(dest);
	}

	fromwire_pubkey(&cursor, &max, &dest->ephemeralkey);
	if (cursor == NULL) {
		*failcode = WIRE_INVALID_ONION_KEY;
		return tal_free(dest);
	}

	/* If max underflows, this returns NULL and fromwire fails. */
	dest->routinginfo = fromwire_tal_arrn(dest, &cursor, &max,
					      max - HMAC_SIZE);
	fromwire_hmac(&cursor, &max, &dest->hmac);

	assert(max == 0);
	if (cursor == NULL) {
		*failcode = WIRE_INVALID_ONION_HMAC;
		return tal_free(dest);
	}

	return dest;
}

/*
 * Generate a pseudo-random byte stream of length `dstlen` from key `k` and