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#include "funding_tx.h"
#include <assert.h>
#include <bitcoin/script.h>
#include <bitcoin/tx.h>
#include <permute_tx.h>
#ifndef SUPERVERBOSE
#define SUPERVERBOSE(...)
#endif
struct bitcoin_tx *funding_tx(const tal_t *ctx,
const struct sha256_double *input_txid,
unsigned int input_txout,
u64 input_satoshis,
u64 funding_satoshis,
const struct pubkey *local_fundingkey,
const struct pubkey *remote_fundingkey,
const struct pubkey *changekey,
u64 feerate_per_kw,
u64 dust_limit_satoshis)
{
struct bitcoin_tx *tx = bitcoin_tx(ctx, 1, 2);
u8 *wscript;
u64 fee, weight;
tx->input[0].txid = *input_txid;
tx->input[0].index = input_txout;
tx->input[0].amount = tal_dup(tx, u64, &input_satoshis);
tx->output[0].amount = funding_satoshis;
wscript = bitcoin_redeem_2of2(tx, local_fundingkey, remote_fundingkey);
SUPERVERBOSE("# funding witness script = %s\n",
tal_hex(wscript, wscript));
tx->output[0].script = scriptpubkey_p2wsh(tx, wscript);
tal_free(wscript);
assert(input_satoshis >= funding_satoshis);
tx->output[1].script = scriptpubkey_p2wpkh(tx, changekey);
/* Calculate what weight will be once we've signed. */
weight = measure_tx_cost(tx) + 4 * (73 + 34);
fee = weight * feerate_per_kw / 1000;
/* Too small an output after fee? Drop it. */
if (input_satoshis - funding_satoshis < dust_limit_satoshis + fee)
tal_resize(&tx->output, 1);
else {
tx->output[1].amount = input_satoshis - funding_satoshis - fee;
permute_outputs(tx->output, tal_count(tx->output), NULL);
}
return tx;
}
void sign_funding_tx(struct bitcoin_tx *funding,
const struct pubkey *inputkey,
const struct privkey *input_privkey)
{
secp256k1_ecdsa_signature sig;
u8 *subscript = scriptpubkey_p2pkh(funding, inputkey);
sign_tx_input(funding, 0, subscript, NULL, input_privkey, inputkey,
&sig);
tal_free(subscript);
funding->input[0].script = bitcoin_redeem_p2pkh(funding, inputkey, &sig);
}