Function bolt11_decode_nosig

common/bolt11.c:592–843

Extracts signature but does not check it. */

/* Extracts signature but does not check it. */
struct bolt11 *bolt11_decode_nosig(const tal_t *ctx, const char *str,
				   const struct feature_set *our_features,
				   const char *description,
				   const struct chainparams *must_be_chain,
				   struct sha256 *hash,
				   u5 **sig,
				   bool *have_n,
				   char **fail)
{
	char *hrp, *amountstr, *prefix;
	u5 *data;
	size_t data_len;
	struct bolt11 *b11 = new_bolt11(ctx, NULL);
	struct hash_u5 hu5;
	bool have_p = false, have_d = false, have_h = false,
		have_x = false, have_c = false, have_s = false, have_m = false;

	*have_n = false;
	b11->routes = tal_arr(b11, struct route_info *, 0);

	/* BOLT #11:
	 *
	 * If a URI scheme is desired, the current recommendation is to either
	 * use 'lightning:' as a prefix before the BOLT-11 encoding
	 */
	if (strstarts(str, "lightning:") || strstarts(str, "LIGHTNING:"))
		str += strlen("lightning:");

	if (strlen(str) < 8)
		return decode_fail(b11, fail, "Bad bech32 string");

	hrp = tal_arr(tmpctx, char, strlen(str) - 6);
	data = tal_arr(tmpctx, u5, strlen(str) - 8);

	if (bech32_decode(hrp, data, &data_len, str, (size_t)-1)
	    != BECH32_ENCODING_BECH32)
		return decode_fail(b11, fail, "Bad bech32 string");

	/* For signature checking at the end. */
	hash_u5_init(&hu5, hrp);

	/* BOLT #11:
	 *
	 * The human-readable part of a Lightning invoice consists of two sections:
	 * 1. `prefix`: `ln` + BIP-0173 currency prefix (e.g. `lnbc` for Bitcoin mainnet,
	 *    `lntb` for Bitcoin testnet, `lntbs` for Bitcoin signet, and `lnbcrt` for Bitcoin regtest)
	 * 1. `amount`: optional number in that currency, followed by an optional
	 *    `multiplier` letter. The unit encoded here is the 'social' convention of a payment unit -- in the case of Bitcoin the unit is 'bitcoin' NOT satoshis.
	*/
	prefix = tal_strndup(tmpctx, hrp, strcspn(hrp, "0123456789"));

	/* BOLT #11:
	 *
	 * A reader...if it does NOT understand the `prefix`... MUST fail the payment.
	 */
	if (!strstarts(prefix, "ln"))
		return decode_fail(b11, fail,
				   "Prefix '%s' does not start with ln", prefix);