136 lines
4.8 KiB
C
136 lines
4.8 KiB
C
/* Commit tx without HTLC support; needed for openingd. */
|
|
#ifndef LIGHTNING_COMMON_INITIAL_COMMIT_TX_H
|
|
#define LIGHTNING_COMMON_INITIAL_COMMIT_TX_H
|
|
#include "config.h"
|
|
#include <bitcoin/chainparams.h>
|
|
#include <bitcoin/pubkey.h>
|
|
#include <bitcoin/tx.h>
|
|
#include <common/htlc.h>
|
|
#include <common/utils.h>
|
|
|
|
struct bitcoin_outpoint;
|
|
struct keyset;
|
|
struct wally_tx_output;
|
|
|
|
/* BOLT #3:
|
|
*
|
|
* This obscures the number of commitments made on the channel in the
|
|
* case of unilateral close, yet still provides a useful index for
|
|
* both nodes (who know the `payment_basepoint`s) to quickly find a
|
|
* revoked commitment transaction.
|
|
*/
|
|
u64 commit_number_obscurer(const struct pubkey *opener_payment_basepoint,
|
|
const struct pubkey *accepter_payment_basepoint);
|
|
|
|
|
|
/* The base weight of a commitment tx */
|
|
static inline size_t commit_tx_base_weight(size_t num_untrimmed_htlcs,
|
|
bool option_anchor_outputs,
|
|
bool option_anchors_zero_fee_htlc_tx)
|
|
{
|
|
size_t weight;
|
|
size_t num_outputs;
|
|
|
|
/* BOLT #3:
|
|
*
|
|
* The base fee for a commitment transaction:
|
|
* - MUST be calculated to match:
|
|
* 1. Start with `weight` = 724 (1124 if `option_anchors` applies).
|
|
*/
|
|
if (option_anchor_outputs || option_anchors_zero_fee_htlc_tx) {
|
|
weight = 1124;
|
|
num_outputs = 4;
|
|
} else {
|
|
weight = 724;
|
|
num_outputs = 2;
|
|
}
|
|
/* BOLT #3:
|
|
*
|
|
* 2. For each committed HTLC, if that output is not trimmed as
|
|
* specified in [Trimmed Outputs](#trimmed-outputs), add 172
|
|
* to `weight`.
|
|
*/
|
|
weight += 172 * num_untrimmed_htlcs;
|
|
num_outputs += num_untrimmed_htlcs;
|
|
|
|
/* Extra fields for Elements */
|
|
weight += elements_tx_overhead(chainparams, 1, num_outputs);
|
|
|
|
return weight;
|
|
}
|
|
|
|
/* Helper to calculate the base fee if we have this many htlc outputs */
|
|
static inline struct amount_sat commit_tx_base_fee(u32 feerate_per_kw,
|
|
size_t num_untrimmed_htlcs,
|
|
bool option_anchor_outputs,
|
|
bool option_anchors_zero_fee_htlc_tx)
|
|
{
|
|
return amount_tx_fee(feerate_per_kw,
|
|
commit_tx_base_weight(num_untrimmed_htlcs,
|
|
option_anchor_outputs,
|
|
option_anchors_zero_fee_htlc_tx));
|
|
}
|
|
|
|
/**
|
|
* initial_commit_tx: create (unsigned) commitment tx to spend the funding tx output
|
|
* @ctx: context to allocate transaction and @htlc_map from.
|
|
* @funding, @funding_sats: funding outpoint and amount
|
|
* @funding_keys: funding bitcoin keys
|
|
* @opener: is the LOCAL or REMOTE paying the fee?
|
|
* @keyset: keys derived for this commit tx.
|
|
* @feerate_per_kw: feerate to use
|
|
* @dust_limit: dust limit below which to trim outputs.
|
|
* @self_pay: amount to pay directly to self
|
|
* @other_pay: amount to pay directly to the other side
|
|
* @self_reserve: reserve the other side insisted we have
|
|
* @obscured_commitment_number: number to encode in commitment transaction
|
|
* @direct_outputs: If non-NULL, fill with pointers to the direct (non-HTLC) outputs (or NULL if none).
|
|
* @side: side to generate commitment transaction for.
|
|
* @option_anchor_outputs: does option_anchor_outputs apply to this channel?
|
|
* @err_reason: When NULL is returned, this will point to a human readable reason.
|
|
*
|
|
* We need to be able to generate the remote side's tx to create signatures,
|
|
* but the BOLT is expressed in terms of generating our local commitment
|
|
* transaction, so we carefully use the terms "self" and "other" here.
|
|
*/
|
|
struct bitcoin_tx *initial_commit_tx(const tal_t *ctx,
|
|
const struct bitcoin_outpoint *funding,
|
|
struct amount_sat funding_sats,
|
|
const struct pubkey funding_key[NUM_SIDES],
|
|
enum side opener,
|
|
u16 to_self_delay,
|
|
const struct keyset *keyset,
|
|
u32 feerate_per_kw,
|
|
struct amount_sat dust_limit,
|
|
struct amount_msat self_pay,
|
|
struct amount_msat other_pay,
|
|
struct amount_sat self_reserve,
|
|
u64 obscured_commitment_number,
|
|
struct wally_tx_output *direct_outputs[NUM_SIDES],
|
|
enum side side,
|
|
u32 csv_lock,
|
|
bool option_anchor_outputs,
|
|
bool option_anchors_zero_fee_htlc_tx,
|
|
char** err_reason);
|
|
|
|
/* try_subtract_fee - take away this fee from the opener (and return true), or all if insufficient (and return false). */
|
|
bool try_subtract_fee(enum side opener, enum side side,
|
|
struct amount_sat base_fee,
|
|
struct amount_msat *self,
|
|
struct amount_msat *other);
|
|
|
|
/* Generate the witness script for the to-self output:
|
|
* scriptpubkey_p2wsh(ctx, wscript) gives the scriptpubkey */
|
|
u8 *to_self_wscript(const tal_t *ctx,
|
|
u16 to_self_delay,
|
|
u32 csv,
|
|
const struct keyset *keyset);
|
|
|
|
/* To-other is simply: scriptpubkey_p2wpkh(tx, keyset->other_payment_key) */
|
|
|
|
/* If we determine we need one, append this anchor output */
|
|
void tx_add_anchor_output(struct bitcoin_tx *tx,
|
|
const struct pubkey *funding_key);
|
|
|
|
#endif /* LIGHTNING_COMMON_INITIAL_COMMIT_TX_H */
|