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onchain_control.c
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#include "config.h"
#include <bitcoin/feerate.h>
#include <bitcoin/script.h>
#include <ccan/cast/cast.h>
#include <ccan/tal/str/str.h>
#include <common/htlc_tx.h>
#include <common/key_derive.h>
#include <common/psbt_keypath.h>
#include <common/type_to_string.h>
#include <db/exec.h>
#include <errno.h>
#include <hsmd/hsmd_wiregen.h>
#include <hsmd/permissions.h>
#include <inttypes.h>
#include <lightningd/chaintopology.h>
#include <lightningd/channel.h>
#include <lightningd/channel_control.h>
#include <lightningd/coin_mvts.h>
#include <lightningd/hsm_control.h>
#include <lightningd/onchain_control.h>
#include <lightningd/peer_control.h>
#include <lightningd/subd.h>
#include <onchaind/onchaind_wiregen.h>
#include <wallet/txfilter.h>
#include <wally_bip32.h>
#include <wally_psbt.h>
#include <wire/wire_sync.h>
/* We dump all the known preimages when onchaind starts up. */
static void onchaind_tell_fulfill(struct channel *channel)
{
struct htlc_in_map_iter ini;
struct htlc_in *hin;
u8 *msg;
struct lightningd *ld = channel->peer->ld;
for (hin = htlc_in_map_first(ld->htlcs_in, &ini);
hin;
hin = htlc_in_map_next(ld->htlcs_in, &ini)) {
if (hin->key.channel != channel)
continue;
/* BOLT #5:
*
* A local node:
* - if it receives (or already possesses) a payment preimage
* for an unresolved HTLC output that it has been offered AND
* for which it has committed to an outgoing HTLC:
* - MUST *resolve* the output by spending it, using the
* HTLC-success transaction.
* - MUST NOT reveal its own preimage when it's not the final recipient...
* - MUST resolve the output of that HTLC-success transaction.
* - otherwise:
* - if the *remote node* is NOT irrevocably committed to
* the HTLC:
* - MUST NOT *resolve* the output by spending it.
*/
/* We only set preimage once it's irrevocably committed, and
* we spend even if we don't have an outgoing HTLC (eg. local
* payment complete) */
if (!hin->preimage)
continue;
msg = towire_onchaind_known_preimage(channel, hin->preimage);
subd_send_msg(channel->owner, take(msg));
}
}
/* If we want to know if this HTLC is missing, return depth. */
static bool tell_if_missing(const struct channel *channel,
struct htlc_stub *stub,
bool *tell_immediate)
{
struct htlc_out *hout;
/* Keep valgrind happy. */
*tell_immediate = false;
/* Don't care about incoming HTLCs, just ones we offered. */
if (stub->owner == REMOTE)
return false;
/* Might not be a current HTLC. */
hout = find_htlc_out(channel->peer->ld->htlcs_out, channel, stub->id);
if (!hout)
return false;
/* BOLT #5:
*
* - for any committed HTLC that does NOT have an output in this
* commitment transaction:
* - once the commitment transaction has reached reasonable depth:
* - MUST fail the corresponding incoming HTLC (if any).
* - if no *valid* commitment transaction contains an output
* corresponding to the HTLC.
* - MAY fail the corresponding incoming HTLC sooner.
*/
if (hout->hstate >= RCVD_ADD_REVOCATION
&& hout->hstate < SENT_REMOVE_REVOCATION)
*tell_immediate = true;
log_debug(channel->log,
"We want to know if htlc %"PRIu64" is missing (%s)",
hout->key.id, *tell_immediate ? "immediate" : "later");
return true;
}
static void handle_onchain_init_reply(struct channel *channel, const u8 *msg)
{
struct htlc_stub *stubs;
u64 commit_num;
bool *tell, *tell_immediate;
if (!fromwire_onchaind_init_reply(msg, &commit_num)) {
channel_internal_error(channel, "Invalid onchaind_init_reply %s",
tal_hex(tmpctx, msg));
return;
}
/* FIXME: We may already be ONCHAIN state when we implement restart! */
channel_set_state(channel,
FUNDING_SPEND_SEEN,
ONCHAIN,
REASON_UNKNOWN,
"Onchain init reply");
/* Tell it about any relevant HTLCs */
/* FIXME: Filter by commitnum! */
stubs = wallet_htlc_stubs(tmpctx, channel->peer->ld->wallet, channel,
commit_num);
tell = tal_arr(stubs, bool, tal_count(stubs));
tell_immediate = tal_arr(stubs, bool, tal_count(stubs));
for (size_t i = 0; i < tal_count(stubs); i++) {
tell[i] = tell_if_missing(channel, &stubs[i],
&tell_immediate[i]);
}
msg = towire_onchaind_htlcs(channel, stubs, tell, tell_immediate);
subd_send_msg(channel->owner, take(msg));
/* Tell it about any preimages we know. */
onchaind_tell_fulfill(channel);
}
/**
* Notify onchaind about the depth change of the watched tx.
*/
static void onchain_tx_depth(struct channel *channel,
const struct bitcoin_txid *txid,
unsigned int depth)
{
u8 *msg;
msg = towire_onchaind_depth(channel, txid, depth);
subd_send_msg(channel->owner, take(msg));
}
/**
* Entrypoint for the txwatch callback, calls onchain_tx_depth.
*/
static enum watch_result onchain_tx_watched(struct lightningd *ld,
const struct bitcoin_txid *txid,
const struct bitcoin_tx *tx,
unsigned int depth,
struct channel *channel)
{
u32 blockheight = get_block_height(ld->topology);
if (tx != NULL) {
struct bitcoin_txid txid2;
bitcoin_txid(tx, &txid2);
if (!bitcoin_txid_eq(txid, &txid2)) {
channel_internal_error(channel, "Txid for %s is not %s",
type_to_string(tmpctx,
struct bitcoin_tx,
tx),
type_to_string(tmpctx,
struct bitcoin_txid,
txid));
return DELETE_WATCH;
}
}
if (depth == 0) {
log_unusual(channel->log, "Chain reorganization!");
channel_set_owner(channel, NULL);
/* We will most likely be freed, so this is a noop */
return KEEP_WATCHING;
}
/* Store the channeltx so we can replay later */
wallet_channeltxs_add(ld->wallet, channel,
WIRE_ONCHAIND_DEPTH, txid, 0, blockheight);
onchain_tx_depth(channel, txid, depth);
return KEEP_WATCHING;
}
static void watch_tx_and_outputs(struct channel *channel,
const struct bitcoin_tx *tx);
/**
* Notify onchaind that an output was spent and register new watches.
*/
static void onchain_txo_spent(struct channel *channel, const struct bitcoin_tx *tx, size_t input_num, u32 blockheight)
{
u8 *msg;
/* Onchaind needs all inputs, since it uses those to compare
* with existing spends (which can vary, with feerate changes). */
struct tx_parts *parts = tx_parts_from_wally_tx(tmpctx, tx->wtx,
-1, -1);
watch_tx_and_outputs(channel, tx);
msg = towire_onchaind_spent(channel, parts, input_num, blockheight);
subd_send_msg(channel->owner, take(msg));
}
/**
* Entrypoint for the txowatch callback, stores tx and calls onchain_txo_spent.
*/
static enum watch_result onchain_txo_watched(struct channel *channel,
const struct bitcoin_tx *tx,
size_t input_num,
const struct block *block)
{
struct bitcoin_txid txid;
bitcoin_txid(tx, &txid);
/* Store the channeltx so we can replay later */
wallet_channeltxs_add(channel->peer->ld->wallet, channel,
WIRE_ONCHAIND_SPENT, &txid, input_num,
block->height);
onchain_txo_spent(channel, tx, input_num, block->height);
/* We don't need to keep watching: If this output is double-spent
* (reorg), we'll get a zero depth cb to onchain_tx_watched, and
* restart onchaind. */
return DELETE_WATCH;
}
/* To avoid races, we watch the tx and all outputs. */
static void watch_tx_and_outputs(struct channel *channel,
const struct bitcoin_tx *tx)
{
struct bitcoin_outpoint outpoint;
struct txwatch *txw;
struct lightningd *ld = channel->peer->ld;
bitcoin_txid(tx, &outpoint.txid);
/* Make txwatch a parent of txo watches, so we can unwatch together. */
txw = watch_txid(channel->owner, ld->topology,
&outpoint.txid,
onchain_tx_watched, channel);
for (outpoint.n = 0; outpoint.n < tx->wtx->num_outputs; outpoint.n++)
watch_txo(txw, ld->topology, channel, &outpoint,
onchain_txo_watched);
}
static void handle_onchain_log_coin_move(struct channel *channel, const u8 *msg)
{
struct chain_coin_mvt *mvt = tal(NULL, struct chain_coin_mvt);
if (!fromwire_onchaind_notify_coin_mvt(msg, mvt)) {
channel_internal_error(channel, "Invalid onchain notify_coin_mvt");
return;
}
/* Any 'ignored' payments get registed to the wallet */
if (!mvt->account_name)
mvt->account_name = type_to_string(mvt, struct channel_id,
&channel->cid);
else
mvt->originating_acct = type_to_string(mvt, struct channel_id,
&channel->cid);
notify_chain_mvt(channel->peer->ld, mvt);
tal_free(mvt);
}
static void handle_onchain_unwatch_tx(struct channel *channel, const u8 *msg)
{
struct bitcoin_txid txid;
struct txwatch *txw;
if (!fromwire_onchaind_unwatch_tx(msg, &txid)) {
channel_internal_error(channel, "Invalid onchain_unwatch_tx");
return;
}
/* Frees the txo watches, too: see watch_tx_and_outputs() */
txw = find_txwatch(channel->peer->ld->topology, &txid,
onchain_tx_watched, channel);
if (!txw)
log_unusual(channel->log, "Can't unwatch txid %s",
type_to_string(tmpctx, struct bitcoin_txid, &txid));
tal_free(txw);
}
static void handle_extracted_preimage(struct channel *channel, const u8 *msg)
{
struct preimage preimage;
if (!fromwire_onchaind_extracted_preimage(msg, &preimage)) {
channel_internal_error(channel, "Invalid extracted_preimage");
return;
}
onchain_fulfilled_htlc(channel, &preimage);
}
static void handle_missing_htlc_output(struct channel *channel, const u8 *msg)
{
struct htlc_stub htlc;
if (!fromwire_onchaind_missing_htlc_output(msg, &htlc)) {
channel_internal_error(channel, "Invalid missing_htlc_output");
return;
}
/* We only set tell_if_missing on LOCAL htlcs */
if (htlc.owner != LOCAL) {
channel_internal_error(channel,
"onchaind_missing_htlc_output: htlc %"PRIu64" is not local!",
htlc.id);
return;
}
/* BOLT #5:
*
* - for any committed HTLC that does NOT have an output in this
* commitment transaction:
* - once the commitment transaction has reached reasonable depth:
* - MUST fail the corresponding incoming HTLC (if any).
* - if no *valid* commitment transaction contains an output
* corresponding to the HTLC.
* - MAY fail the corresponding incoming HTLC sooner.
*/
onchain_failed_our_htlc(channel, &htlc, "missing in commitment tx", false);
}
static void handle_onchain_htlc_timeout(struct channel *channel, const u8 *msg)
{
struct htlc_stub htlc;
if (!fromwire_onchaind_htlc_timeout(msg, &htlc)) {
channel_internal_error(channel, "Invalid onchain_htlc_timeout");
return;
}
/* It should tell us about timeouts on our LOCAL htlcs */
if (htlc.owner != LOCAL) {
channel_internal_error(channel,
"onchaind_htlc_timeout: htlc %"PRIu64" is not local!",
htlc.id);
return;
}
/* BOLT #5:
*
* - if the commitment transaction HTLC output has *timed out* and
* hasn't been *resolved*:
* - MUST *resolve* the output by spending it using the HTLC-timeout
* transaction.
*/
onchain_failed_our_htlc(channel, &htlc, "timed out", true);
}
static void handle_irrevocably_resolved(struct channel *channel, const u8 *msg UNUSED)
{
/* FIXME: Implement check_htlcs to ensure no dangling hout->in ptrs! */
free_htlcs(channel->peer->ld, channel);
log_info(channel->log, "onchaind complete, forgetting peer");
/* This will also free onchaind. */
delete_channel(channel);
}
/**
* onchain_add_utxo -- onchaind is telling us about an UTXO we own
*/
static void onchain_add_utxo(struct channel *channel, const u8 *msg)
{
struct chain_coin_mvt *mvt;
u32 blockheight;
struct bitcoin_outpoint outpoint;
u32 csv_lock;
struct amount_sat amount;
struct pubkey *commitment_point;
u8 *scriptPubkey;
if (!fromwire_onchaind_add_utxo(
tmpctx, msg, &outpoint, &commitment_point,
&amount, &blockheight, &scriptPubkey,
&csv_lock)) {
log_broken(channel->log,
"onchaind gave invalid add_utxo message: %s",
tal_hex(msg, msg));
return;
}
assert(blockheight);
outpointfilter_add(channel->peer->ld->wallet->owned_outpoints,
&outpoint);
log_debug(channel->log, "adding utxo to watch %s, csv %u",
type_to_string(tmpctx, struct bitcoin_outpoint, &outpoint),
csv_lock);
wallet_add_onchaind_utxo(channel->peer->ld->wallet,
&outpoint, scriptPubkey,
blockheight, amount, channel,
commitment_point,
csv_lock);
mvt = new_coin_wallet_deposit(msg, &outpoint, blockheight,
amount, DEPOSIT);
mvt->originating_acct = type_to_string(mvt, struct channel_id,
&channel->cid);
notify_chain_mvt(channel->peer->ld, mvt);
}
static void onchain_annotate_txout(struct channel *channel, const u8 *msg)
{
struct bitcoin_outpoint outpoint;
enum wallet_tx_type type;
if (!fromwire_onchaind_annotate_txout(msg, &outpoint, &type))
fatal("onchaind gave invalid onchain_annotate_txout "
"message: %s",
tal_hex(msg, msg));
wallet_annotate_txout(channel->peer->ld->wallet, &outpoint, type,
channel->dbid);
}
static void onchain_annotate_txin(struct channel *channel, const u8 *msg)
{
struct bitcoin_txid txid;
enum wallet_tx_type type;
u32 innum;
if (!fromwire_onchaind_annotate_txin(msg, &txid, &innum, &type))
fatal("onchaind gave invalid onchain_annotate_txin "
"message: %s",
tal_hex(msg, msg));
wallet_annotate_txin(channel->peer->ld->wallet, &txid, innum, type,
channel->dbid);
}
/* All onchaind-produced txs are actually of the same form: */
struct onchain_signing_info {
/* Fields common to every callback: */
struct channel *channel;
/* Minimum block */
u32 minblock;
/* Block we want this mined by */
u32 deadline_block;
/* Witness script for tx */
u8 *wscript;
/* Trailing element for witness stack */
const tal_t *stack_elem;
/* Information for consider_onchain_rebroadcast */
struct amount_sat fee;
struct bitcoin_outpoint out;
struct amount_sat out_sats;
u32 to_self_delay;
u32 locktime;
u8 *(*sign)(const tal_t *ctx,
const struct bitcoin_tx *tx,
const struct onchain_signing_info *info);
/* Information for consider_onchain_htlc_tx_rebroadcast */
struct bitcoin_tx *raw_htlc_tx;
/* Tagged union (for sanity checking!) */
enum onchaind_wire msgtype;
union {
/* WIRE_ONCHAIND_SPEND_HTLC_TIMEDOUT */
struct {
u64 commit_num;
} htlc_timedout;
/* WIRE_ONCHAIND_SPEND_PENALTY */
struct {
struct secret remote_per_commitment_secret;
} spend_penalty;
/* WIRE_ONCHAIND_SPEND_HTLC_SUCCESS */
struct {
u64 commit_num;
struct bitcoin_signature remote_htlc_sig;
struct preimage preimage;
} htlc_success;
/* WIRE_ONCHAIND_SPEND_HTLC_TIMEOUT */
struct {
u64 commit_num;
struct bitcoin_signature remote_htlc_sig;
} htlc_timeout;
/* WIRE_ONCHAIND_SPEND_FULFILL */
struct {
struct pubkey remote_per_commitment_point;
struct preimage preimage;
} fulfill;
/* WIRE_ONCHAIND_SPEND_HTLC_EXPIRED */
struct {
struct pubkey remote_per_commitment_point;
} htlc_expired;
} u;
};
/* If we don't care / don't know */
static u32 infinite_block_deadline(const struct chain_topology *topo)
{
return get_block_height(topo) + 300;
}
static struct onchain_signing_info *new_signing_info(const tal_t *ctx,
struct channel *channel,
enum onchaind_wire msgtype)
{
struct onchain_signing_info *info = tal(ctx, struct onchain_signing_info);
info->channel = channel;
info->msgtype = msgtype;
return info;
}
static u8 *sign_tx_to_us(const tal_t *ctx,
const struct bitcoin_tx *tx,
const struct onchain_signing_info *info)
{
assert(info->msgtype == WIRE_ONCHAIND_SPEND_TO_US);
return towire_hsmd_sign_any_delayed_payment_to_us(ctx,
info->u.htlc_timedout.commit_num,
tx, info->wscript,
0,
&info->channel->peer->id,
info->channel->dbid);
}
static u8 *sign_penalty(const tal_t *ctx,
const struct bitcoin_tx *tx,
const struct onchain_signing_info *info)
{
assert(info->msgtype == WIRE_ONCHAIND_SPEND_PENALTY);
return towire_hsmd_sign_any_penalty_to_us(ctx,
&info->u.spend_penalty.remote_per_commitment_secret,
tx, info->wscript,
0,
&info->channel->peer->id,
info->channel->dbid);
}
static u8 *sign_htlc_success(const tal_t *ctx,
const struct bitcoin_tx *tx,
const struct onchain_signing_info *info)
{
const bool anchor_outputs = channel_type_has_anchors(info->channel->type);
assert(info->msgtype == WIRE_ONCHAIND_SPEND_HTLC_SUCCESS);
return towire_hsmd_sign_any_local_htlc_tx(ctx,
info->u.htlc_success.commit_num,
tx, info->wscript,
anchor_outputs,
0,
&info->channel->peer->id,
info->channel->dbid);
}
static u8 *sign_htlc_timeout(const tal_t *ctx,
const struct bitcoin_tx *tx,
const struct onchain_signing_info *info)
{
const bool anchor_outputs = channel_type_has_anchors(info->channel->type);
assert(info->msgtype == WIRE_ONCHAIND_SPEND_HTLC_TIMEOUT);
return towire_hsmd_sign_any_local_htlc_tx(ctx,
info->u.htlc_timeout.commit_num,
tx, info->wscript,
anchor_outputs,
0,
&info->channel->peer->id,
info->channel->dbid);
}
static u8 *sign_fulfill(const tal_t *ctx,
const struct bitcoin_tx *tx,
const struct onchain_signing_info *info)
{
const bool anchor_outputs = channel_type_has_anchors(info->channel->type);
assert(info->msgtype == WIRE_ONCHAIND_SPEND_FULFILL);
return towire_hsmd_sign_any_remote_htlc_to_us(ctx,
&info->u.fulfill.remote_per_commitment_point,
tx, info->wscript,
anchor_outputs,
0,
&info->channel->peer->id,
info->channel->dbid);
}
static u8 *sign_htlc_expired(const tal_t *ctx,
const struct bitcoin_tx *tx,
const struct onchain_signing_info *info)
{
const bool anchor_outputs = channel_type_has_anchors(info->channel->type);
assert(info->msgtype == WIRE_ONCHAIND_SPEND_HTLC_EXPIRED);
return towire_hsmd_sign_any_remote_htlc_to_us(ctx,
&info->u.htlc_expired.remote_per_commitment_point,
tx, info->wscript,
anchor_outputs,
0,
&info->channel->peer->id,
info->channel->dbid);
}
/* Matches bitcoin_witness_sig_and_element! */
static const struct onchain_witness_element **
onchain_witness_sig_and_element(const tal_t *ctx, u8 **witness)
{
struct onchain_witness_element **welements;
welements = tal_arr(ctx, struct onchain_witness_element *,
tal_count(witness));
for (size_t i = 0; i < tal_count(welements); i++) {
welements[i] = tal(welements, struct onchain_witness_element);
/* See bitcoin_witness_sig_and_element */
welements[i]->is_signature = (i == 0);
welements[i]->witness = tal_dup_talarr(welements[i], u8,
witness[i]);
}
return cast_const2(const struct onchain_witness_element **, welements);
}
/* Matches bitcoin_witness_htlc_success_tx & bitcoin_witness_htlc_timeout_tx! */
static const struct onchain_witness_element **
onchain_witness_htlc_tx(const tal_t *ctx, u8 **witness)
{
struct onchain_witness_element **welements;
welements = tal_arr(ctx, struct onchain_witness_element *,
tal_count(witness));
for (size_t i = 0; i < tal_count(welements); i++) {
welements[i] = tal(welements, struct onchain_witness_element);
/* See bitcoin_witness_htlc_success_tx / bitcoin_witness_htlc_timeout_tx */
welements[i]->is_signature = (i == 1 || i == 2);
welements[i]->witness = tal_dup_talarr(welements[i], u8,
witness[i]);
}
return cast_const2(const struct onchain_witness_element **, welements);
}
/* Make normal 1-input-1-output tx to us, but don't sign it yet.
*
* If worthwhile is not NULL, we set it to true normally, or false if
* we had to lower fees so much it's unlikely to get mined
* (i.e. "don't wait up!").
*/
static struct bitcoin_tx *onchaind_tx_unsigned(const tal_t *ctx,
struct channel *channel,
const struct onchain_signing_info *info,
struct amount_sat *fee,
bool *worthwhile)
{
struct bitcoin_tx *tx;
struct amount_sat amt;
size_t weight;
struct pubkey final_key;
struct ext_key final_wallet_ext_key;
u64 block_target;
struct lightningd *ld = channel->peer->ld;
bip32_pubkey(ld, &final_key, channel->final_key_idx);
if (bip32_key_from_parent(ld->bip32_base,
channel->final_key_idx,
BIP32_FLAG_KEY_PUBLIC,
&final_wallet_ext_key) != WALLY_OK) {
channel_internal_error(channel,
"Could not derive final_wallet_ext_key %"PRIu64,
channel->final_key_idx);
return NULL;
}
tx = bitcoin_tx(ctx, chainparams, 1, 1, info->locktime);
bitcoin_tx_add_input(tx, &info->out, info->to_self_delay,
NULL, info->out_sats, NULL, info->wscript);
/* FIXME should this be p2tr now? */
bitcoin_tx_add_output(
tx, scriptpubkey_p2wpkh(tmpctx, &final_key), NULL, info->out_sats);
psbt_add_keypath_to_last_output(tx, channel->final_key_idx, &final_wallet_ext_key, false /* is_taproot */);
/* Worst-case sig is 73 bytes */
weight = bitcoin_tx_weight(tx) + 1 + 3 + 73 + 0 + tal_count(info->wscript);
weight += elements_tx_overhead(chainparams, 1, 1);
block_target = info->deadline_block;
for (;;) {
u32 feerate;
feerate = feerate_for_target(ld->topology, block_target);
*fee = amount_tx_fee(feerate, weight);
log_debug(channel->log,
"Feerate for target %"PRIu64" (%+"PRId64" blocks) is %u, fee %s of %s",
block_target,
block_target - get_block_height(ld->topology),
feerate,
type_to_string(tmpctx, struct amount_sat, fee),
type_to_string(tmpctx, struct amount_sat,
&info->out_sats));
/* If we can afford fee and it's not dust, we're done */
if (amount_sat_sub(&amt, info->out_sats, *fee)
&& amount_sat_greater_eq(amt, channel->our_config.dust_limit))
break;
/* Hmm, can't afford with recommended fee. Try increasing deadline! */
block_target++;
/* If we can't even afford at FEERATE_FLOOR, something is wrong! */
if (feerate == FEERATE_FLOOR) {
amt = channel->our_config.dust_limit;
/* Not quite true, but Never Happens */
*fee = AMOUNT_SAT(0);
log_broken(channel->log, "TX can't afford minimal feerate"
"; setting output to %s",
type_to_string(tmpctx, struct amount_sat, &amt));
break;
}
}
/* If we anticipate waiting a long time (say, 20 blocks past
* the deadline), tell onchaind not to wait */
if (worthwhile) {
*worthwhile = (block_target < info->deadline_block + (u64)20);
if (!*worthwhile) {
log_unusual(channel->log,
"Lowballing feerate for %s sats from %u to %u (deadline %u->%"PRIu64"):"
" won't count on it being spent!",
type_to_string(tmpctx, struct amount_sat, &info->out_sats),
feerate_for_target(ld->topology, info->deadline_block),
feerate_for_target(ld->topology, block_target),
info->deadline_block, block_target);
}
}
/* If we came close to target, it's worthwhile to wait for. */
if (block_target != info->deadline_block)
log_debug(channel->log, "Had to adjust deadline from %u to %"PRIu64" for %s",
info->deadline_block, block_target,
type_to_string(tmpctx, struct amount_sat, &info->out_sats));
bitcoin_tx_output_set_amount(tx, 0, amt);
bitcoin_tx_finalize(tx);
return tx;
}
static u8 **sign_and_get_witness(const tal_t *ctx,
const struct channel *channel,
struct bitcoin_tx *tx,
const struct onchain_signing_info *info)
{
const u8 *msg;
struct bitcoin_signature sig;
struct lightningd *ld = channel->peer->ld;
msg = hsm_sync_req(tmpctx, ld, take(info->sign(NULL, tx, info)));
if (!fromwire_hsmd_sign_tx_reply(msg, &sig))
fatal("Reading sign_tx_reply: %s", tal_hex(tmpctx, msg));
return bitcoin_witness_sig_and_element(ctx, &sig, info->stack_elem,
tal_bytelen(info->stack_elem),
info->wscript);
}
/* Always sets *welements, returns tx. Sets *worthwhile to false if
* it wasn't worthwhile at the given feerate (and it had to drop feerate).
* Returns NULL iff it called channel_internal_error().
*/
static struct bitcoin_tx *onchaind_tx(const tal_t *ctx,
struct channel *channel,
const struct onchain_signing_info *info,
struct amount_sat *fee,
bool *worthwhile,
const struct onchain_witness_element ***welements)
{
struct bitcoin_tx *tx;
u8 **witness;
tx = onchaind_tx_unsigned(ctx, channel, info, fee, worthwhile);
if (!tx)
return NULL;
/* Now sign, and set witness */
witness = sign_and_get_witness(NULL, channel, tx, info);
*welements = onchain_witness_sig_and_element(ctx, witness);
bitcoin_tx_input_set_witness(tx, 0, take(witness));
return tx;
}
static bool consider_onchain_rebroadcast(struct channel *channel,
const struct bitcoin_tx **tx,
struct onchain_signing_info *info)
{
struct bitcoin_tx *newtx;
struct amount_sat newfee;
struct bitcoin_txid oldtxid, newtxid;
u8 **witness;
newtx = onchaind_tx_unsigned(tmpctx, channel, info, &newfee, NULL);
if (!newtx)
return true;
/* FIXME: Don't RBF if fee is not sufficiently increased? */
/* OK! RBF time! */
witness = sign_and_get_witness(NULL, channel, newtx, info);
bitcoin_tx_input_set_witness(newtx, 0, take(witness));
bitcoin_txid(newtx, &newtxid);
bitcoin_txid(*tx, &oldtxid);
/* Don't spam the logs! */
log_(channel->log,
amount_sat_less_eq(newfee, info->fee) ? LOG_DBG : LOG_INFORM,
NULL, false,
"RBF onchain txid %s (fee %s) with txid %s (fee %s)",
type_to_string(tmpctx, struct bitcoin_txid, &oldtxid),
fmt_amount_sat(tmpctx, info->fee),
type_to_string(tmpctx, struct bitcoin_txid, &newtxid),
fmt_amount_sat(tmpctx, newfee));
log_debug(channel->log,
"RBF %s->%s",
type_to_string(tmpctx, struct bitcoin_tx, *tx),
type_to_string(tmpctx, struct bitcoin_tx, newtx));
/* FIXME: This is ugly, but we want the same parent as old tx. */
tal_steal(tal_parent(*tx), newtx);
tal_free(*tx);
*tx = newtx;
info->fee = newfee;
return true;
}
static bool consider_onchain_htlc_tx_rebroadcast(struct channel *channel,
const struct bitcoin_tx **tx,
struct onchain_signing_info *info)
{
struct amount_sat change, excess;
struct utxo **utxos;
u32 feerate;
size_t weight;
struct bitcoin_tx *newtx;
size_t locktime;
struct bitcoin_txid oldtxid, newtxid;
struct wally_psbt *psbt;
const u8 *msg;
struct amount_sat oldfee, newfee;
struct lightningd *ld = channel->peer->ld;
/* We can't do much without anchor outputs (we could CPFP?) */
if (!channel_type_has_anchors(channel->type))
return true;
/* Note that we can have UTXOs taken from us if there are a lot of
* closes going on, so we re-fetch them every time. This is messy,
* but since that bitcoind will take the highest feerate ones, it will
* priority order them for us. */
feerate = feerate_for_target(ld->topology, info->deadline_block);
/* Make a copy to play with */
newtx = clone_bitcoin_tx(tmpctx, info->raw_htlc_tx);
weight = bitcoin_tx_weight(newtx);
utxos = tal_arr(tmpctx, struct utxo *, 0);
/* We'll need this to regenerate PSBT */
if (wally_psbt_get_locktime(newtx->psbt, &locktime) != WALLY_OK) {
log_broken(channel->log, "Cannot get psbt locktime?!");
return true;
}
/* Keep attaching input inputs until we get sufficient fees */
while (tx_feerate(newtx) < feerate) {
struct utxo *utxo;
/* Get fresh utxo */
utxo = wallet_find_utxo(tmpctx, ld->wallet,
get_block_height(ld->topology),
NULL,
0, /* FIXME: unused! */
0, false,
cast_const2(const struct utxo **, utxos));
if (!utxo) {
/* Did we get nothing at all? */
if (tal_count(utxos) == 0) {
log_unusual(channel->log,
"We want to bump HTLC fee, but no funds!");
return true;
}
/* At least we got something, right? */
break;
}
/* Add to any UTXOs we have already */
tal_arr_expand(&utxos, utxo);
weight += bitcoin_tx_simple_input_weight(utxo->is_p2sh);
}
/* We were happy with feerate already (can't happen with zero-fee
* anchors!)? */
if (tal_count(utxos) == 0)
return true;
/* PSBT knows how to spend utxos; append to existing. */
psbt = psbt_using_utxos(tmpctx, ld->wallet, utxos, locktime,
BITCOIN_TX_RBF_SEQUENCE, newtx->psbt);
/* Subtract how much we pay in fees for this tx, to calc excess. */
if (!amount_sat_sub(&excess,
psbt_compute_fee(psbt),
amount_sat((u64)weight * feerate / 1000))) {
excess = AMOUNT_SAT(0);
}
change = change_amount(excess, feerate, weight);
if (!amount_sat_eq(change, AMOUNT_SAT(0))) {
/* Append change output. */
struct pubkey final_key;
bip32_pubkey(ld, &final_key, channel->final_key_idx);
psbt_append_output(psbt,
scriptpubkey_p2wpkh(tmpctx, &final_key),
change);
}
/* Sanity check: are we paying more in fees than HTLC is worth? */
if (amount_sat_greater(psbt_compute_fee(psbt), info->out_sats)) {
log_unusual(channel->log,
"Not spending %s in fees to get an HTLC worth %s!",
fmt_amount_sat(tmpctx, psbt_compute_fee(psbt)),
fmt_amount_sat(tmpctx, info->out_sats));
return true;
}
/* Now, get HSM to sign off. */
msg = towire_hsmd_sign_htlc_tx_mingle(NULL,
&channel->peer->id,
channel->dbid,
cast_const2(const struct utxo **,
utxos),
psbt);
msg = hsm_sync_req(tmpctx, ld, take(msg));
if (!fromwire_hsmd_sign_htlc_tx_mingle_reply(tmpctx, msg, &psbt))
fatal("Reading sign_htlc_tx_mingle_reply: %s",
tal_hex(tmpctx, msg));
if (!psbt_finalize(psbt))
fatal("Non-final PSBT from hsm: %s",
type_to_string(tmpctx, struct wally_psbt, psbt));
newtx = tal(tal_parent(*tx), struct bitcoin_tx);
newtx->chainparams = chainparams;
newtx->wtx = psbt_final_tx(newtx, psbt);
assert(newtx->wtx);
newtx->psbt = tal_steal(newtx, psbt);
bitcoin_txid(*tx, &oldtxid);
bitcoin_txid(newtx, &newtxid);
oldfee = bitcoin_tx_compute_fee(*tx);
newfee = bitcoin_tx_compute_fee(newtx);
/* Don't spam the logs! */
log_(channel->log,
amount_sat_less_eq(newfee, oldfee) ? LOG_DBG : LOG_INFORM,
NULL, false,
"RBF HTLC txid %s (fee %s) with txid %s (fee %s)",
type_to_string(tmpctx, struct bitcoin_txid, &oldtxid),
fmt_amount_sat(tmpctx, oldfee),
type_to_string(tmpctx, struct bitcoin_txid, &newtxid),
fmt_amount_sat(tmpctx, newfee));
tal_free(*tx);
*tx = newtx;
return true;
}
/* We want to mine a success tx before they can timeout */
static u32 htlc_incoming_deadline(const struct channel *channel, u64 htlc_id)