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#ifndef LIGHTNING_COMMON_HTLC_TX_H
#define LIGHTNING_COMMON_HTLC_TX_H
#include "config.h"
#include <bitcoin/chainparams.h>
#include <common/amount.h>
#include <common/htlc.h>
#include <common/utils.h>
struct bitcoin_signature;
struct bitcoin_txid;
struct keyset;
struct preimage;
struct pubkey;
struct ripemd160;
/** Attempt to compute the elements overhead given a base bitcoin size.
*
* The overhead consists of 2 empty proofs for the transaction, 6 bytes of
* proofs per input and 35 bytes per output. In addition the explicit fee
* output will add 9 bytes and the per output overhead as well.
*/
/* FIXME: This seems to be a generalization of the logic in initial_commit_tx.h
* and should be in bitcoin/tx.h */
static inline size_t elements_add_overhead(size_t weight, size_t incount,
size_t outcount)
{
if (chainparams->is_elements) {
/* Each transaction has surjection and rangeproof (both empty
* for us as long as we use unblinded L-BTC transactions). */
weight += 2 * 4;
/* For elements we also need to add the fee output and the
* overhead for rangeproofs into the mix. */
weight += (8 + 1) * 4; /* Bitcoin style output */
/* All outputs have a bit of elements overhead */
weight += (32 + 1 + 1 + 1) * 4 * (outcount + 1); /* Elements added fields */
/* Inputs have 6 bytes of blank proofs attached. */
weight += 6 * incount;
}
return weight;
}
static inline struct amount_sat htlc_timeout_fee(u32 feerate_per_kw,
bool option_anchor_outputs)
{
/* BOLT #3:
*
* The fee for an HTLC-timeout transaction:
* - MUST BE calculated to match:
* 1. Multiply `feerate_per_kw` by 663 (666 if `option_anchor_outputs`
* applies) and divide by 1000 (rounding down).
*/
u32 base;
if (option_anchor_outputs)
base = 666;
else
base = 663;
return amount_tx_fee(elements_add_overhead(base, 1, 1), feerate_per_kw);
}
static inline struct amount_sat htlc_success_fee(u32 feerate_per_kw,
bool option_anchor_outputs)
{
/* BOLT #3:
*
* The fee for an HTLC-success transaction:
* - MUST BE calculated to match:
* 1. Multiply `feerate_per_kw` by 703 (706 if `option_anchor_outputs`
* applies) and divide by 1000 (rounding down).
*/
u32 base;
if (option_anchor_outputs)
base = 706;
else
base = 703;
return amount_tx_fee(elements_add_overhead(base, 1, 1), feerate_per_kw);
}
/* Create HTLC-success tx to spend a received HTLC commitment tx
* output; doesn't fill in input witness. */
struct bitcoin_tx *htlc_success_tx(const tal_t *ctx,
const struct chainparams *chainparams,
const struct bitcoin_txid *commit_txid,
unsigned int commit_output_number,
const u8 *commit_wscript,
struct amount_msat htlc_msatoshi,
u16 to_self_delay,
u32 feerate_per_kw,
const struct keyset *keyset,
bool option_anchor_outputs);
/* Fill in the witness for HTLC-success tx produced above. */
void htlc_success_tx_add_witness(struct bitcoin_tx *htlc_success,
const struct abs_locktime *htlc_abstimeout,
const struct pubkey *localkey,
const struct pubkey *remotekey,
const struct bitcoin_signature *localsig,
const struct bitcoin_signature *remotesig,
const struct preimage *payment_preimage,
const struct pubkey *revocationkey,
bool option_anchor_outputs);
/* Create HTLC-timeout tx to spend an offered HTLC commitment tx
* output; doesn't fill in input witness. */
struct bitcoin_tx *htlc_timeout_tx(const tal_t *ctx,
const struct chainparams *chainparams,
const struct bitcoin_txid *commit_txid,
unsigned int commit_output_number,
const u8 *commit_wscript,
struct amount_msat htlc_msatoshi,
u32 cltv_expiry,
u16 to_self_delay,
u32 feerate_per_kw,
const struct keyset *keyset,
bool option_anchor_outputs);
/* Fill in the witness for HTLC-timeout tx produced above. */
void htlc_timeout_tx_add_witness(struct bitcoin_tx *htlc_timeout,
const struct pubkey *localkey,
const struct pubkey *remotekey,
const struct sha256 *payment_hash,
const struct pubkey *revocationkey,
const struct bitcoin_signature *localsig,
const struct bitcoin_signature *remotesig,
bool option_anchor_outputs);
/* Generate the witness script for an HTLC the other side offered:
* scriptpubkey_p2wsh(ctx, wscript) gives the scriptpubkey */
u8 *htlc_received_wscript(const tal_t *ctx,
const struct ripemd160 *ripemd,
const struct abs_locktime *expiry,
const struct keyset *keyset,
bool option_anchor_outputs);
/* Generate the witness script for an HTLC this side offered:
* scriptpubkey_p2wsh(ctx, wscript) gives the scriptpubkey */
u8 *htlc_offered_wscript(const tal_t *ctx,
const struct ripemd160 *ripemd,
const struct keyset *keyset,
bool option_anchor_outputs);
#endif /* LIGHTNING_COMMON_HTLC_TX_H */