core-lightning/channeld/watchtower.c
Rusty Russell 1abbc3d06a channeld: simply exit if hsmd vanishes.
We currently die when gossipd vanishes, but our direct connection will
go away.  We then complain if the node is shutting down while we're talking
to hsmd.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2022-02-08 11:15:52 +10:30

122 lines
4 KiB
C

#include "config.h"
#include <bitcoin/feerate.h>
#include <bitcoin/script.h>
#include <channeld/channeld.h>
#include <channeld/watchtower.h>
#include <common/features.h>
#include <common/htlc_tx.h>
#include <common/keyset.h>
#include <common/status.h>
#include <common/type_to_string.h>
#include <hsmd/hsmd_wiregen.h>
#include <wire/wire_sync.h>
static const u8 ONE = 0x1;
const struct bitcoin_tx *
penalty_tx_create(const tal_t *ctx,
const struct channel *channel,
u32 penalty_feerate,
u8 *final_scriptpubkey,
const struct secret *revocation_preimage,
const struct bitcoin_txid *commitment_txid,
s16 to_them_outnum, struct amount_sat to_them_sats,
int hsm_fd)
{
u8 *wscript;
struct bitcoin_tx *tx;
struct keyset keyset;
size_t weight;
const u8 *msg;
struct amount_sat fee, min_out, amt;
struct bitcoin_signature sig;
u32 locktime = 0;
bool option_static_remotekey = channel_has(channel, OPT_STATIC_REMOTEKEY);
u8 **witness;
u32 remote_to_self_delay = channel->config[REMOTE].to_self_delay;
const struct amount_sat dust_limit = channel->config[LOCAL].dust_limit;
BUILD_ASSERT(sizeof(struct secret) == sizeof(*revocation_preimage));
const struct secret remote_per_commitment_secret = *revocation_preimage;
struct pubkey remote_per_commitment_point;
const struct basepoints *basepoints = channel->basepoints;
struct bitcoin_outpoint outpoint;
if (to_them_outnum == -1 ||
amount_sat_less_eq(to_them_sats, dust_limit)) {
status_debug(
"Cannot create penalty transaction because there "
"is no non-dust to_them output in the commitment.");
return NULL;
}
outpoint.txid = *commitment_txid;
outpoint.n = to_them_outnum;
if (!pubkey_from_secret(&remote_per_commitment_secret, &remote_per_commitment_point))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Failed derive from per_commitment_secret %s",
type_to_string(tmpctx, struct secret,
&remote_per_commitment_secret));
if (!derive_keyset(&remote_per_commitment_point,
&basepoints[REMOTE],
&basepoints[LOCAL],
option_static_remotekey,
&keyset))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Failed deriving keyset");
/* FIXME: csv_lock */
wscript = bitcoin_wscript_to_local(tmpctx, remote_to_self_delay, 1,
&keyset.self_revocation_key,
&keyset.self_delayed_payment_key);
tx = bitcoin_tx(ctx, chainparams, 1, 1, locktime);
bitcoin_tx_add_input(tx, &outpoint, 0xFFFFFFFF,
NULL, to_them_sats, NULL, wscript);
bitcoin_tx_add_output(tx, final_scriptpubkey, NULL, to_them_sats);
/* Worst-case sig is 73 bytes */
weight = bitcoin_tx_weight(tx) + 1 + 3 + 73 + 0 + tal_count(wscript);
weight += elements_tx_overhead(chainparams, 1, 1);
fee = amount_tx_fee(penalty_feerate, weight);
if (!amount_sat_add(&min_out, dust_limit, fee))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Cannot add dust_limit %s and fee %s",
type_to_string(tmpctx, struct amount_sat, &dust_limit),
type_to_string(tmpctx, struct amount_sat, &fee));
if (amount_sat_less(to_them_sats, min_out)) {
/* FIXME: We should use SIGHASH_NONE so others can take it */
fee = amount_tx_fee(feerate_floor(), weight);
}
/* This can only happen if feerate_floor() is still too high; shouldn't
* happen! */
if (!amount_sat_sub(&amt, to_them_sats, fee)) {
amt = dust_limit;
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"TX can't afford minimal feerate"
"; setting output to %s",
type_to_string(tmpctx, struct amount_sat, &amt));
}
bitcoin_tx_output_set_amount(tx, 0, amt);
bitcoin_tx_finalize(tx);
u8 *hsm_sign_msg =
towire_hsmd_sign_penalty_to_us(tmpctx, &remote_per_commitment_secret,
tx, wscript);
msg = hsm_req(tmpctx, hsm_sign_msg);
if (!fromwire_hsmd_sign_tx_reply(msg, &sig))
status_failed(STATUS_FAIL_HSM_IO,
"Reading sign_tx_reply: %s", tal_hex(tmpctx, msg));
witness = bitcoin_witness_sig_and_element(tx, &sig, &ONE, sizeof(ONE),
wscript);
bitcoin_tx_input_set_witness(tx, 0, take(witness));
return tx;
}