Function proposal_should_rbf

onchaind/onchaind.c:1071–1150

proposal_should_rbf * * @brief the given output just increased its depth, * so the proposal for it should be RBFed and * rebroadcast. * * @desc precondition: the given output must have an * rbfable proposal as per `proposal_is_rbfable`. */

 * rbfable proposal as per `proposal_is_rbfable`.
 */
static void proposal_should_rbf(struct tracked_output *out)
{
	struct bitcoin_tx *tx = NULL;
	u32 depth;

	assert(out->proposal);
	assert(proposal_is_rbfable(out->proposal));

	depth = out->depth;

	/* Do not RBF at depth 1.
	 *
	 * Since we react to *onchain* events, whatever proposal we made,
	 * the output for that proposal is already at depth 1.
	 *
	 * Since our initial proposal was broadcasted with the output at
	 * depth 1, we should not RBF until a new block arrives, which is
	 * at depth 2.
	 */
	if (depth <= 1)
		return;

	if (out->proposal->tx_type == OUR_PENALTY_TX) {
		u32 max_depth = to_self_delay[REMOTE];
		u32 my_depth = depth;
		size_t weight = bitcoin_tx_weight(out->proposal->tx);
		struct amount_sat initial_amount;
		struct amount_sat new_amount;

		if (max_depth >= 1)
			max_depth -= 1;
		if (my_depth >= max_depth)
			my_depth = max_depth;

		bitcoin_tx_output_get_amount_sat(out->proposal->tx, 0,
						 &initial_amount);

		/* Compute the new output amount for the RBF.  */
		new_amount = compute_penalty_output_amount(initial_amount,
							   my_depth, max_depth,
							   weight);
		assert(amount_sat_less_eq(new_amount, initial_amount));
		/* Recreate the penalty tx.  */
		tx = replace_penalty_tx_to_us(tmpctx,
					      &penalty_to_us,
					      out->proposal->tx, &new_amount);

		/* We also update the output's value, so our accounting
		 * is correct. */
		out->sat = new_amount;

		status_debug("Created RBF OUR_PENALTY_TX with output %s "
			     "(originally %s) for depth %"PRIu32"/%"PRIu32".",
			     type_to_string(tmpctx, struct amount_sat,
					    &new_amount),
			     type_to_string(tmpctx, struct amount_sat,
					    &initial_amount),
			     depth, to_self_delay[LOCAL]);