Function htlc_set_add

lightningd/htlc_set.c:97–224

}

void htlc_set_add(struct lightningd *ld,
		  struct htlc_in *hin,
		  struct amount_msat total_msat,
		  const struct secret *payment_secret)
{
	struct htlc_set *set;
	const struct invoice_details *details;

	/* BOLT #4:
	 * The final node:
	 *   - MUST fail the HTLC if dictated by Requirements under
	 *     [Failure Messages](#failure-messages)
	 *     - Note: "amount paid" specified there is the `total_msat` field.
	 */
	details = invoice_check_payment(tmpctx, ld, &hin->payment_hash,
					total_msat, payment_secret);
	if (!details) {
		local_fail_in_htlc(hin,
				   take(failmsg_incorrect_or_unknown(NULL, ld, hin)));
		return;
	}

	/* If we insist on a payment secret, it must always have it */
	if (feature_is_set(details->features, COMPULSORY_FEATURE(OPT_PAYMENT_SECRET))
	    && !payment_secret) {
		log_debug(ld->log, "Missing payment_secret, but required for %s",
			  type_to_string(tmpctx, struct sha256,
					 &hin->payment_hash));
		local_fail_in_htlc(hin,
				   take(failmsg_incorrect_or_unknown(NULL, ld, hin)));
		return;
	}

	/* BOLT #4:
	 *  - otherwise, if it supports `basic_mpp`:
	 *    - MUST add it to the HTLC set corresponding to that `payment_hash`.
	 */
	set = htlc_set_map_get(&ld->htlc_sets, &hin->payment_hash);
	if (!set)
		set = new_htlc_set(ld, hin, total_msat);
	else {
		/* BOLT #4:
		 *
		 * if it supports `basic_mpp`:
		 * ...
		 *  - otherwise, if the total `amount_msat` of this HTLC set is
		 *    less than `total_msat`:
		 * ...
		 *     - MUST require `payment_secret` for all HTLCs in the set.
		 */
		/* We check this now, since we want to fail with this as soon
		 * as possible, to avoid other probing attacks. */
		if (!payment_secret) {
			local_fail_in_htlc(hin, take(failmsg_incorrect_or_unknown(NULL, ld, hin)));
			return;
		}
		tal_arr_expand(&set->htlcs, hin);
	}