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onchaind: move feerate grinding into its own function.

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We'll want to use this for htlc_success txs as well.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2017-09-16 09:07:06 +09:30
parent 561a73328b
commit 2259faf3a9
1 changed files with 81 additions and 80 deletions
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161
onchaind/onchain.c
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@ -36,6 +36,9 @@ static u64 feerate_per_kw;
/* The dust limit to use when we generate transactions. */
static u64 dust_limit_satoshis;
/* The CSV delays for each side. */
static u32 to_self_delay[NUM_SIDES];
/* If we broadcast a tx, or need a delay to resolve the output. */
struct proposed_resolution {
/* This can be NULL if our proposal is to simply ignore it after depth */
@ -69,12 +72,11 @@ struct tracked_output {
/* We use the same feerate for htlcs and commit transactions; we don't
* record what it was, so we brute-force it. */
struct feerate_range {
struct {
u32 min, max;
};
} feerate_range;
static void init_feerate_range(struct feerate_range *feerate_range,
u64 funding_satoshi,
static void init_feerate_range(u64 funding_satoshi,
const struct bitcoin_tx *commit_tx)
{
size_t i, max_untrimmed_htlcs;
@ -85,7 +87,7 @@ static void init_feerate_range(struct feerate_range *feerate_range,
/* We don't know how many trimmed HTLCs there are, so they could
* be making fee entirely. */
feerate_range->min = 0;
feerate_range.min = 0;
/* But we can estimate the maximum fee rate:
*
@ -96,15 +98,14 @@ static void init_feerate_range(struct feerate_range *feerate_range,
else
max_untrimmed_htlcs = tal_count(commit_tx->output) - 2;
feerate_range->max = (fee + 999) * 1000
feerate_range.max = (fee + 999) * 1000
/ (724 + 172 * max_untrimmed_htlcs);
status_trace("Initial feerate %u to %u",
feerate_range->min, feerate_range->max);
feerate_range.min, feerate_range.max);
}
static void narrow_feerate_range(struct feerate_range *feerate_range,
u64 fee, u32 multiplier)
static void narrow_feerate_range(u64 fee, u32 multiplier)
{
u32 min, max;
@ -118,12 +119,44 @@ static void narrow_feerate_range(struct feerate_range *feerate_range,
status_trace("Fee %"PRIu64" gives feerate min/max %u/%u",
fee, min, max);
if (max < feerate_range->max)
feerate_range->max = max;
if (min > feerate_range->min)
feerate_range->min = min;
if (max < feerate_range.max)
feerate_range.max = max;
if (min > feerate_range.min)
feerate_range.min = min;
status_trace("Feerate now %u to %u",
feerate_range->min, feerate_range->max);
feerate_range.min, feerate_range.max);
}
/* We vary feerate until signature they offered matches: we're more
* likely to be near max. */
static bool grind_feerate(struct bitcoin_tx *commit_tx,
const secp256k1_ecdsa_signature *remotesig,
const u8 *wscript,
u64 multiplier)
{
u64 prev_fee = UINT64_MAX;
u64 input_amount = *commit_tx->input[0].amount;
for (s64 i = feerate_range.max; i >= feerate_range.min; i--) {
u64 fee = feerate_per_kw * multiplier / 1000;
if (fee > input_amount)
continue;
/* Minor optimization: don't check same fee twice */
if (fee == prev_fee)
continue;
prev_fee = fee;
commit_tx->output[0].amount = input_amount - fee;
if (!check_tx_sig(commit_tx, 0, NULL, wscript,
&keyset->other_payment_key, remotesig))
continue;
narrow_feerate_range(fee, multiplier);
return true;
}
return false;
}
static const char *tx_type_name(enum tx_type tx_type)
@ -629,13 +662,11 @@ static struct bitcoin_tx *tx_to_us(const tal_t *ctx,
static void resolve_our_htlc_ourcommit(struct tracked_output *out,
const u8 *wscript,
const struct htlc_stub *htlc,
u32 to_self_delay,
struct feerate_range *feerate_range,
const struct privkey *local_payment_privkey,
const secp256k1_ecdsa_signature *remotesig)
{
struct bitcoin_tx *tx;
u64 prev_fee = UINT64_MAX;
secp256k1_ecdsa_signature localsig;
/* BOLT #5:
*
@ -650,7 +681,7 @@ static void resolve_our_htlc_ourcommit(struct tracked_output *out,
* "On-chain HTLC Transaction Handling".
*/
tx = htlc_timeout_tx(out, &out->txid, out->outnum, out->satoshi * 1000,
htlc->cltv_expiry, to_self_delay, 0, keyset);
htlc->cltv_expiry, to_self_delay[LOCAL], 0, keyset);
wscript = bitcoin_wscript_htlc_offer_ripemd160(tx,
&keyset->self_payment_key,
@ -658,53 +689,32 @@ static void resolve_our_htlc_ourcommit(struct tracked_output *out,
&htlc->ripemd,
&keyset->self_revocation_key);
/* We vary feerate until signature they offered matches: we're
* more likely to be near max. */
for (s64 i = feerate_range->max; i >= feerate_range->min; i--) {
u64 fee = htlc_timeout_fee(i);
secp256k1_ecdsa_signature localsig;
/* BOLT #3:
*
* The fee for an HTLC-timeout transaction MUST BE calculated to
* match:
*
* 1. Multiply `feerate_per_kw` by 663 and divide by 1000 (rounding
* down).
*/
if (!grind_feerate(tx, remotesig, wscript, 663))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not find feerate for signature on"
" HTLC timeout between %u and %u",
feerate_range.min, feerate_range.max);
if (fee > out->satoshi)
continue;
sign_tx_input(tx, 0, NULL, wscript, local_payment_privkey,
&keyset->self_payment_key, &localsig);
/* Minor optimization: don't check same fee twice */
if (fee == prev_fee)
continue;
tx->input[0].witness
= bitcoin_htlc_offer_spend_timeout(tx->input,
&localsig,
remotesig,
wscript);
prev_fee = fee;
tx->output[0].amount = out->satoshi - fee;
if (!check_tx_sig(tx, 0, NULL, wscript,
&keyset->other_payment_key, remotesig))
continue;
/* OK, we found correct fee! Narrow range for next time. */
/* BOLT #3:
*
* The fee for an HTLC-timeout transaction MUST BE calculated
* to match:
*
* 1. Multiply `feerate_per_kw` by 663 and divide by 1000
* (rounding down).
*/
narrow_feerate_range(feerate_range, fee, 663);
sign_tx_input(tx, 0, NULL, wscript, local_payment_privkey,
&keyset->self_payment_key, &localsig);
tx->input[0].witness
= bitcoin_htlc_offer_spend_timeout(tx->input,
&localsig,
remotesig,
wscript);
propose_resolution_at_block(out, tx, htlc->cltv_expiry,
OUR_HTLC_TIMEOUT_TO_US);
tal_free(wscript);
return;
}
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not find feerate for signature on HTLC timeout"
" between %u and %u",
feerate_range->min, feerate_range->max);
propose_resolution_at_block(out, tx, htlc->cltv_expiry,
OUR_HTLC_TIMEOUT_TO_US);
tal_free(wscript);
}
static void resolve_our_htlc_theircommit(struct tracked_output *out,
@ -793,7 +803,6 @@ static void handle_our_unilateral(const struct bitcoin_tx *tx,
const struct pubkey *local_payment_basepoint,
const struct pubkey *local_delayed_payment_basepoint,
const struct pubkey *our_wallet_pubkey,
u32 to_self_delay,
u64 commit_num,
const struct htlc_stub *htlcs,
const secp256k1_ecdsa_signature *htlc_sigs,
@ -805,12 +814,11 @@ static void handle_our_unilateral(const struct bitcoin_tx *tx,
struct privkey local_delayedprivkey, local_payment_privkey;
struct pubkey local_per_commitment_point;
struct keyset *ks;
struct feerate_range feerate_range;
size_t i;
set_state(ONCHAIND_OUR_UNILATERAL);
init_feerate_range(&feerate_range, outs[0]->satoshi, tx);
init_feerate_range(outs[0]->satoshi, tx);
/* BOLT #5:
*
@ -871,7 +879,7 @@ static void handle_our_unilateral(const struct bitcoin_tx *tx,
"Deriving local_delayeprivkey for %"PRIu64,
commit_num);
local_wscript = to_self_wscript(tmpctx, to_self_delay, keyset);
local_wscript = to_self_wscript(tmpctx, to_self_delay[LOCAL], keyset);
/* Figure out what to-us output looks like. */
script[LOCAL] = scriptpubkey_p2wsh(tmpctx, local_wscript);
@ -883,7 +891,7 @@ static void handle_our_unilateral(const struct bitcoin_tx *tx,
htlc_scripts = derive_htlc_scripts(htlcs, LOCAL);
status_trace("Script to-me: %u: %s (%s)",
to_self_delay,
to_self_delay[LOCAL],
tal_hex(trc, script[LOCAL]),
tal_hex(trc, local_wscript));
status_trace("Script to-them: %s",
@ -927,7 +935,7 @@ static void handle_our_unilateral(const struct bitcoin_tx *tx,
*
* <local_delayedsig> 0
*/
to_us = tx_to_us(out, out, to_self_delay, 0,
to_us = tx_to_us(out, out, to_self_delay[LOCAL], 0,
local_wscript, our_wallet_pubkey,
&local_delayedprivkey,
&keyset->self_delayed_payment_key);
@ -936,7 +944,7 @@ static void handle_our_unilateral(const struct bitcoin_tx *tx,
*
* If the output is spent (as recommended), the output
* is *resolved* by the spending transaction */
propose_resolution(out, to_us, to_self_delay,
propose_resolution(out, to_us, to_self_delay[LOCAL],
OUR_UNILATERAL_TO_US_RETURN_TO_WALLET);
script[LOCAL] = NULL;
@ -976,8 +984,7 @@ static void handle_our_unilateral(const struct bitcoin_tx *tx,
tx->output[i].amount,
OUR_HTLC);
resolve_our_htlc_ourcommit(out, htlc_scripts[j],
&htlcs[j], to_self_delay,
&feerate_range,
&htlcs[j],
&local_payment_privkey,
htlc_sigs);
/* Each of these consumes one HTLC signature */
@ -1022,7 +1029,6 @@ static void handle_their_unilateral(const struct bitcoin_tx *tx,
const struct pubkey *remote_payment_basepoint,
const struct pubkey *remote_delayed_payment_basepoint,
const struct pubkey *our_wallet_pubkey,
u32 to_self_delay,
u64 commit_num,
const struct htlc_stub *htlcs,
struct tracked_output **outs)
@ -1031,13 +1037,12 @@ static void handle_their_unilateral(const struct bitcoin_tx *tx,
u8 **htlc_scripts;
u8 *remote_wscript, *script[NUM_SIDES];
struct keyset *ks;
struct feerate_range feerate_range;
struct privkey local_payment_privkey;
size_t i;
set_state(ONCHAIND_THEIR_UNILATERAL);
init_feerate_range(&feerate_range, outs[0]->satoshi, tx);
init_feerate_range(outs[0]->satoshi, tx);
/* BOLT #5:
*
@ -1102,7 +1107,7 @@ static void handle_their_unilateral(const struct bitcoin_tx *tx,
"Deriving local_delayeprivkey for %"PRIu64,
commit_num);
remote_wscript = to_self_wscript(tmpctx, to_self_delay, keyset);
remote_wscript = to_self_wscript(tmpctx, to_self_delay[REMOTE], keyset);
/* Figure out what to-them output looks like. */
script[REMOTE] = scriptpubkey_p2wsh(tmpctx, remote_wscript);
@ -1114,7 +1119,7 @@ static void handle_their_unilateral(const struct bitcoin_tx *tx,
htlc_scripts = derive_htlc_scripts(htlcs, REMOTE);
status_trace("Script to-them: %u: %s (%s)",
to_self_delay,
to_self_delay[REMOTE],
tal_hex(trc, script[REMOTE]),
tal_hex(trc, remote_wscript));
status_trace("Script to-me: %s",
@ -1218,7 +1223,6 @@ int main(int argc, char *argv[])
remote_per_commit_point, old_remote_per_commit_point,
remote_revocation_basepoint, remote_delayed_payment_basepoint;
enum side funder;
u32 to_self_delay[NUM_SIDES];
struct basepoints basepoints;
struct shachain shachain;
struct bitcoin_tx *tx;
@ -1339,7 +1343,6 @@ int main(int argc, char *argv[])
&basepoints.payment,
&basepoints.delayed_payment,
&ourwallet_pubkey,
to_self_delay[LOCAL],
commit_num,
htlcs,
remote_htlc_sigs,
@ -1376,7 +1379,6 @@ int main(int argc, char *argv[])
&remote_payment_basepoint,
&remote_delayed_payment_basepoint,
&ourwallet_pubkey,
to_self_delay[REMOTE],
commit_num,
htlcs, outs);
} else if (commit_num == revocations_received(&shachain) + 1) {
@ -1389,7 +1391,6 @@ int main(int argc, char *argv[])
&remote_payment_basepoint,
&remote_delayed_payment_basepoint,
&ourwallet_pubkey,
to_self_delay[REMOTE],
commit_num,
htlcs, outs);
} else