struct bitcoin_tx *create_close_tx(const tal_t *ctx,
const u8 *our_script,
const u8 *their_script,
const struct bitcoin_txid *anchor_txid,
unsigned int anchor_index,
struct amount_sat funding,
struct amount_sat to_us,
struct amount_sat to_them,
struct amount_sat dust_limit)
{
struct bitcoin_tx *tx;
size_t num_outputs = 0;
struct amount_sat total_out;
u8 *script;
assert(amount_sat_add(&total_out, to_us, to_them));
assert(amount_sat_less_eq(total_out, funding));
/* BOLT #3:
*
* ## Closing Transaction
*
* Note that there are two possible variants for each node.
*
* * version: 2
* * locktime: 0
* * txin count: 1
*/
/* Now create close tx: one input, two outputs. */
tx = bitcoin_tx(ctx, 1, 2);
/* Our input spends the anchor tx output. */
bitcoin_tx_add_input(tx, anchor_txid, anchor_index,
BITCOIN_TX_DEFAULT_SEQUENCE, &funding, NULL);
if (amount_sat_greater_eq(to_us, dust_limit)) {
script =
tal_dup_arr(tx, u8, our_script, tal_count(our_script), 0);
/* One output is to us. */
bitcoin_tx_add_output(tx, script, &to_us);
num_outputs++;
}
if (amount_sat_greater_eq(to_them, dust_limit)) {
script = tal_dup_arr(tx, u8, their_script,
tal_count(their_script), 0);
/* Other output is to them. */
bitcoin_tx_add_output(tx, script, &to_them);
num_outputs++;
}
/* Can't have no outputs at all! */
if (num_outputs == 0)
return tal_free(tx);
permute_outputs(tx, NULL, NULL);
assert(bitcoin_tx_check(tx));
return tx;
}
struct bitcoin_tx *create_close_tx(secp256k1_context *secpctx,
const tal_t *ctx,
const struct pubkey *our_final,
const struct pubkey *their_final,
const struct sha256_double *anchor_txid,
unsigned int anchor_index,
u64 anchor_satoshis,
uint64_t to_us, uint64_t to_them)
{
struct bitcoin_tx *tx;
const u8 *redeemscript;
/* Now create close tx: one input, two outputs. */
tx = bitcoin_tx(ctx, 1, 2);
/* Our input spends the anchor tx output. */
tx->input[0].txid = *anchor_txid;
tx->input[0].index = anchor_index;
tx->input[0].input_amount = anchor_satoshis;
/* One output is to us. */
tx->output[0].amount = to_us;
redeemscript = bitcoin_redeem_single(tx, our_final);
tx->output[0].script = scriptpubkey_p2sh(tx, redeemscript);
tx->output[0].script_length = tal_count(tx->output[0].script);
/* Other output is to them. */
tx->output[1].amount = to_them;
redeemscript = bitcoin_redeem_single(tx, their_final);
tx->output[1].script = scriptpubkey_p2sh(tx, redeemscript);
tx->output[1].script_length = tal_count(tx->output[1].script);
assert(tx->output[0].amount + tx->output[1].amount
<= tx->input[0].input_amount);
tx->fee = tx->input[0].input_amount
- (tx->output[0].amount + tx->output[1].amount);
permute_outputs(tx->output, 2, NULL);
return tx;
}
struct bitcoin_tx *funding_tx(const tal_t *ctx,
u16 *outnum,
const struct utxo **utxomap,
struct amount_sat funding,
const struct pubkey *local_fundingkey,
const struct pubkey *remote_fundingkey,
struct amount_sat change,
const struct pubkey *changekey,
const struct ext_key *bip32_base)
{
u8 *wscript;
struct bitcoin_tx *tx;
bool has_change = !amount_sat_eq(change, AMOUNT_SAT(0));
tx = tx_spending_utxos(ctx, utxomap, bip32_base, has_change);
wscript = bitcoin_redeem_2of2(tx, local_fundingkey, remote_fundingkey);
SUPERVERBOSE("# funding witness script = %s\n",
tal_hex(wscript, wscript));
bitcoin_tx_add_output(tx, scriptpubkey_p2wsh(tx, wscript), &funding);
tal_free(wscript);
if (has_change) {
const void *map[2];
map[0] = int2ptr(0);
map[1] = int2ptr(1);
bitcoin_tx_add_output(tx, scriptpubkey_p2wpkh(tx, changekey),
&change);
permute_outputs(tx, NULL, map);
*outnum = (map[0] == int2ptr(0) ? 0 : 1);
} else {
*outnum = 0;
}
permute_inputs(tx, (const void **)utxomap);
assert(bitcoin_tx_check(tx));
return tx;
}
