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lightning/onchaind/onchaind.c

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#include <bitcoin/feerate.h>
#include <bitcoin/script.h>
#include <ccan/crypto/shachain/shachain.h>
#include <ccan/mem/mem.h>
#include <ccan/tal/str/str.h>
#include <common/derive_basepoints.h>
#include <common/htlc_tx.h>
#include <common/initial_commit_tx.h>
#include <common/key_derive.h>
#include <common/keyset.h>
#include <common/memleak.h>
#include <common/peer_billboard.h>
#include <common/status.h>
#include <common/subdaemon.h>
#include <common/type_to_string.h>
#include <common/utils.h>
#include <common/version.h>
#include <common/wallet.h>
#include <errno.h>
#include <hsmd/gen_hsm_wire.h>
#include <inttypes.h>
#include <lightningd/channel_state.h>
#include <onchaind/gen_onchain_wire.h>
#include <onchaind/onchain_types.h>
#include <stdio.h>
#include <unistd.h>
#include <wire/wire_sync.h>
#include "gen_onchain_types_names.h"
/* stdin == requests */
#define REQ_FD STDIN_FILENO
#define HSM_FD 3
/* Required in various places: keys for commitment transaction. */
static const struct keyset *keyset;
/* IFF it's their commitment tx: HSM can't derive their per-commitment point! */
static const struct pubkey *remote_per_commitment_point;
/* The commitment number we're dealing with (if not mutual close) */
static u64 commit_num;
/* The feerate to use when we generate transactions. */
static u32 feerate_per_kw;
/* Min and max feerates we ever used */
static u32 min_possible_feerate, max_possible_feerate;
/* The dust limit to use when we generate transactions. */
static struct amount_sat dust_limit;
/* The CSV delays for each side. */
static u32 to_self_delay[NUM_SIDES];
/* Where we send money to (our wallet) */
static struct pubkey our_wallet_pubkey;
/* Their revocation secret (only if they cheated). */
static const struct secret *remote_per_commitment_secret;
/* one value is useful for a few witness scripts */
static const u8 ONE = 0x1;
/* When to tell master about HTLCs which are missing/timed out */
static u32 reasonable_depth;
/* The messages to send at that depth. */
static u8 **missing_htlc_msgs;
/* Does option_static_remotekey apply to this commitment tx? */
bool option_static_remotekey;
/* 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 */
const struct bitcoin_tx *tx;
/* Non-zero if this is CSV-delayed. */
u32 depth_required;
enum tx_type tx_type;
};
/* How it actually got resolved. */
struct resolution {
struct bitcoin_txid txid;
unsigned int depth;
enum tx_type tx_type;
};
struct tracked_output {
enum tx_type tx_type;
struct bitcoin_txid txid;
u32 tx_blockheight;
/* FIXME: Convert all depths to blocknums, then just get new blk msgs */
u32 depth;
u32 outnum;
struct amount_sat sat;
enum output_type output_type;
/* If it is an HTLC, this is set, wscript is non-NULL. */
struct htlc_stub htlc;
const u8 *wscript;
/* If it's an HTLC off our unilateral, this is their sig for htlc_tx */
const struct bitcoin_signature *remote_htlc_sig;
/* Our proposed solution (if any) */
struct proposed_resolution *proposal;
/* If it is resolved. */
struct resolution *resolved;
const struct chainparams *chainparams;
};
/* We vary feerate until signature they offered matches. */
static bool grind_htlc_tx_fee(struct amount_sat *fee,
struct bitcoin_tx *tx,
const struct bitcoin_signature *remotesig,
const u8 *wscript,
u64 weight)
{
struct amount_sat prev_fee = AMOUNT_SAT(UINT64_MAX);
for (u64 i = min_possible_feerate; i <= max_possible_feerate; i++) {
/* 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).
*
* The fee for an HTLC-success transaction:
* - MUST BE calculated to match:
* 1. Multiply `feerate_per_kw` by 703 and divide by 1000
* (rounding down).
*/
struct amount_sat out;
*fee = amount_tx_fee(i, weight);
/* Minor optimization: don't check same fee twice */
if (amount_sat_eq(*fee, prev_fee))
continue;
prev_fee = *fee;
if (!amount_sat_sub(&out, *tx->input_amounts[0], *fee))
break;
bitcoin_tx_output_set_amount(tx, 0, out);
if (!check_tx_sig(tx, 0, NULL, wscript,
&keyset->other_htlc_key, remotesig))
continue;
status_debug("grind feerate_per_kw for %"PRIu64" = %"PRIu64,
weight, i);
return true;
}
return false;
}
static bool set_htlc_timeout_fee(struct bitcoin_tx *tx,
const struct bitcoin_signature *remotesig,
const u8 *wscript)
{
static struct amount_sat fee = AMOUNT_SAT_INIT(UINT64_MAX);
struct amount_sat amount = bitcoin_tx_output_get_amount(tx, 0);
/* 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 (amount_sat_eq(fee, AMOUNT_SAT(UINT64_MAX))) {
struct amount_sat grindfee;
if (grind_htlc_tx_fee(&grindfee, tx, remotesig, wscript, 663)) {
/* Cache this for next time */
fee = grindfee;
return true;
}
return false;
}
if (!amount_sat_sub(&amount, amount, fee))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Cannot deduct htlc-timeout fee %s from tx %s",
type_to_string(tmpctx, struct amount_sat, &fee),
type_to_string(tmpctx, struct bitcoin_tx, tx));
bitcoin_tx_output_set_amount(tx, 0, amount);
return check_tx_sig(tx, 0, NULL, wscript,
&keyset->other_htlc_key, remotesig);
}
static void set_htlc_success_fee(struct bitcoin_tx *tx,
const struct bitcoin_signature *remotesig,
const u8 *wscript)
{
static struct amount_sat amt, fee = AMOUNT_SAT_INIT(UINT64_MAX);
/* BOLT #3:
*
* The fee for an HTLC-success transaction:
* - MUST BE calculated to match:
* 1. Multiply `feerate_per_kw` by 703 and divide by 1000
* (rounding down).
*/
if (amount_sat_eq(fee, AMOUNT_SAT(UINT64_MAX))) {
if (!grind_htlc_tx_fee(&fee, tx, remotesig, wscript, 703))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"htlc_success_fee can't be found "
" for tx %s, signature %s, wscript %s",
type_to_string(tmpctx, struct bitcoin_tx,
tx),
type_to_string(tmpctx,
struct bitcoin_signature,
remotesig),
tal_hex(tmpctx, wscript));
return;
}
amt = bitcoin_tx_output_get_amount(tx, 0);
if (!amount_sat_sub(&amt, amt, fee))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Cannot deduct htlc-success fee %s from tx %s",
type_to_string(tmpctx, struct amount_sat, &fee),
type_to_string(tmpctx, struct bitcoin_tx, tx));
bitcoin_tx_output_set_amount(tx, 0, amt);
if (check_tx_sig(tx, 0, NULL, wscript,
&keyset->other_htlc_key, remotesig))
return;
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"htlc_success_fee %s failed sigcheck "
" for tx %s, signature %s, wscript %s",
type_to_string(tmpctx, struct amount_sat, &fee),
type_to_string(tmpctx, struct bitcoin_tx, tx),
type_to_string(tmpctx, struct bitcoin_signature, remotesig),
tal_hex(tmpctx, wscript));
}
static const char *tx_type_name(enum tx_type tx_type)
{
size_t i;
for (i = 0; enum_tx_type_names[i].name; i++)
if (enum_tx_type_names[i].v == tx_type)
return enum_tx_type_names[i].name;
return "unknown";
}
static const char *output_type_name(enum output_type output_type)
{
size_t i;
for (i = 0; enum_output_type_names[i].name; i++)
if (enum_output_type_names[i].v == output_type)
return enum_output_type_names[i].name;
return "unknown";
}
static u8 *delayed_payment_to_us(const tal_t *ctx,
struct bitcoin_tx *tx,
const u8 *wscript)
{
return towire_hsm_sign_delayed_payment_to_us(ctx, commit_num,
tx, wscript,
*tx->input_amounts[0]);
}
static u8 *remote_htlc_to_us(const tal_t *ctx,
struct bitcoin_tx *tx,
const u8 *wscript)
{
return towire_hsm_sign_remote_htlc_to_us(ctx,
remote_per_commitment_point,
tx, wscript,
*tx->input_amounts[0]);
}
static u8 *penalty_to_us(const tal_t *ctx,
struct bitcoin_tx *tx,
const u8 *wscript)
{
return towire_hsm_sign_penalty_to_us(ctx, remote_per_commitment_secret,
tx, wscript, *tx->input_amounts[0]);
}
/*
* This covers:
* 1. to-us output spend (`<local_delayedsig> 0`)
* 2. the their-commitment, our HTLC timeout case (`<remotehtlcsig> 0`),
* 3. the their-commitment, our HTLC redeem case (`<remotehtlcsig> <payment_preimage>`)
* 4. the their-revoked-commitment, to-local (`<revocation_sig> 1`)
* 5. the their-revoked-commitment, htlc (`<revocation_sig> <revocationkey>`)
*
* Overrides *tx_type if it all turns to dust.
*/
static struct bitcoin_tx *tx_to_us(const tal_t *ctx,
u8 *(*hsm_sign_msg)(const tal_t *ctx,
struct bitcoin_tx *tx,
const u8 *wscript),
struct tracked_output *out,
u32 to_self_delay,
u32 locktime,
const void *elem, size_t elemsize,
const u8 *wscript,
enum tx_type *tx_type)
{
struct bitcoin_tx *tx;
struct amount_sat fee, min_out, amt;
struct bitcoin_signature sig;
size_t weight;
u8 *msg;
u8 **witness;
tx = bitcoin_tx(ctx, out->chainparams, 1, 1);
tx->wtx->locktime = locktime;
bitcoin_tx_add_input(tx, &out->txid, out->outnum, to_self_delay,
out->sat, NULL);
bitcoin_tx_add_output(
tx, scriptpubkey_p2wpkh(tx, &our_wallet_pubkey), out->sat);
/* Worst-case sig is 73 bytes */
weight = measure_tx_weight(tx) + 1 + 3 + 73 + 0 + tal_count(wscript);
fee = amount_tx_fee(feerate_per_kw, weight);
/* Result is trivial? Spend with small feerate, but don't wait
* around for it as it might not confirm. */
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(out->sat, min_out)) {
/* FIXME: We should use SIGHASH_NONE so others can take it */
fee = amount_tx_fee(feerate_floor(), weight);
status_unusual("TX %s amount %s too small to"
" pay reasonable fee, using minimal fee"
" and ignoring",
tx_type_name(*tx_type),
type_to_string(tmpctx, struct amount_sat, &out->sat));
*tx_type = IGNORING_TINY_PAYMENT;
}
/* This can only happen if feerate_floor() is still too high; shouldn't
* happen! */
if (!amount_sat_sub(&amt, out->sat, fee)) {
amt = dust_limit;
status_broken("TX %s can't afford minimal feerate"
"; setting output to %s",
tx_type_name(*tx_type),
type_to_string(tmpctx, struct amount_sat,
&amt));
}
bitcoin_tx_output_set_amount(tx, 0, amt);
if (!wire_sync_write(HSM_FD, take(hsm_sign_msg(NULL, tx, wscript))))
status_failed(STATUS_FAIL_HSM_IO, "Writing sign request to hsm");
msg = wire_sync_read(tmpctx, HSM_FD);
if (!msg || !fromwire_hsm_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, elem,
elemsize, wscript);
bitcoin_tx_input_set_witness(tx, 0, take(witness));
return tx;
}
static void hsm_sign_local_htlc_tx(struct bitcoin_tx *tx,
const u8 *wscript,
struct bitcoin_signature *sig)
{
u8 *msg = towire_hsm_sign_local_htlc_tx(NULL, commit_num,
tx, wscript,
*tx->input_amounts[0]);
if (!wire_sync_write(HSM_FD, take(msg)))
status_failed(STATUS_FAIL_HSM_IO,
"Writing sign_local_htlc_tx to hsm");
msg = wire_sync_read(tmpctx, HSM_FD);
if (!msg || !fromwire_hsm_sign_tx_reply(msg, sig))
status_failed(STATUS_FAIL_HSM_IO,
"Reading sign_local_htlc_tx: %s",
tal_hex(tmpctx, msg));
}
static void hsm_get_per_commitment_point(struct pubkey *per_commitment_point)
{
u8 *msg = towire_hsm_get_per_commitment_point(NULL, commit_num);
struct secret *unused;
if (!wire_sync_write(HSM_FD, take(msg)))
status_failed(STATUS_FAIL_HSM_IO, "Writing sign_htlc_tx to hsm");
msg = wire_sync_read(tmpctx, HSM_FD);
if (!msg
|| !fromwire_hsm_get_per_commitment_point_reply(tmpctx, msg,
per_commitment_point,
&unused))
status_failed(STATUS_FAIL_HSM_IO,
"Reading hsm_get_per_commitment_point_reply: %s",
tal_hex(tmpctx, msg));
}
static struct tracked_output *
new_tracked_output(const struct chainparams *chainparams,
struct tracked_output ***outs,
const struct bitcoin_txid *txid,
u32 tx_blockheight,
enum tx_type tx_type,
u32 outnum,
struct amount_sat sat,
enum output_type output_type,
const struct htlc_stub *htlc,
const u8 *wscript,
const secp256k1_ecdsa_signature *remote_htlc_sig)
{
struct tracked_output *out = tal(*outs, struct tracked_output);
status_debug("Tracking output %u of %s: %s/%s",
outnum,
type_to_string(tmpctx, struct bitcoin_txid, txid),
tx_type_name(tx_type),
output_type_name(output_type));
out->tx_type = tx_type;
out->txid = *txid;
out->tx_blockheight = tx_blockheight;
out->depth = 0;
out->outnum = outnum;
out->sat = sat;
out->output_type = output_type;
out->proposal = NULL;
out->resolved = NULL;
out->chainparams = chainparams;
if (htlc)
out->htlc = *htlc;
out->wscript = tal_steal(out, wscript);
if (remote_htlc_sig) {
struct bitcoin_signature *sig;
sig = tal(out, struct bitcoin_signature);
sig->s = *remote_htlc_sig;
sig->sighash_type = SIGHASH_ALL;
out->remote_htlc_sig = sig;
} else
out->remote_htlc_sig = NULL;
tal_arr_expand(outs, out);
return out;
}
static void ignore_output(struct tracked_output *out)
{
status_debug("Ignoring output %u of %s: %s/%s",
out->outnum,
type_to_string(tmpctx, struct bitcoin_txid, &out->txid),
tx_type_name(out->tx_type),
output_type_name(out->output_type));
out->resolved = tal(out, struct resolution);
out->resolved->txid = out->txid;
out->resolved->depth = 0;
out->resolved->tx_type = SELF;
}
static enum wallet_tx_type onchain_txtype_to_wallet_txtype(enum tx_type t)
{
switch (t) {
case FUNDING_TRANSACTION:
return TX_CHANNEL_FUNDING;
case MUTUAL_CLOSE:
return TX_CHANNEL_CLOSE;
case OUR_UNILATERAL:
return TX_CHANNEL_UNILATERAL;
case THEIR_HTLC_FULFILL_TO_US:
case OUR_HTLC_SUCCESS_TX:
return TX_CHANNEL_HTLC_SUCCESS;
case OUR_HTLC_TIMEOUT_TO_US:
case OUR_HTLC_TIMEOUT_TX:
return TX_CHANNEL_HTLC_TIMEOUT;
case OUR_DELAYED_RETURN_TO_WALLET:
case SELF:
return TX_CHANNEL_SWEEP;
case OUR_PENALTY_TX:
return TX_CHANNEL_PENALTY;
case THEIR_UNILATERAL:
case UNKNOWN_UNILATERAL:
case THEIR_REVOKED_UNILATERAL:
return TX_CHANNEL_UNILATERAL | TX_THEIRS;
case THEIR_HTLC_TIMEOUT_TO_THEM:
return TX_CHANNEL_HTLC_TIMEOUT | TX_THEIRS;
case OUR_HTLC_FULFILL_TO_THEM:
return TX_CHANNEL_HTLC_SUCCESS | TX_THEIRS;
case IGNORING_TINY_PAYMENT:
case UNKNOWN_TXTYPE:
return TX_UNKNOWN;
}
abort();
}
static void proposal_meets_depth(struct tracked_output *out)
{
/* If we simply wanted to ignore it after some depth */
if (!out->proposal->tx) {
ignore_output(out);
return;
}
status_debug("Broadcasting %s (%s) to resolve %s/%s",
tx_type_name(out->proposal->tx_type),
type_to_string(tmpctx, struct bitcoin_tx, out->proposal->tx),
tx_type_name(out->tx_type),
output_type_name(out->output_type));
wire_sync_write(
REQ_FD,
take(towire_onchain_broadcast_tx(
NULL, out->proposal->tx,
onchain_txtype_to_wallet_txtype(out->proposal->tx_type))));
/* Don't wait for this if we're ignoring the tiny payment. */
if (out->proposal->tx_type == IGNORING_TINY_PAYMENT)
ignore_output(out);
/* Otherwise we will get a callback when it's in a block. */
}
static void propose_resolution(struct tracked_output *out,
const struct bitcoin_tx *tx,
unsigned int depth_required,
enum tx_type tx_type)
{
status_debug("Propose handling %s/%s by %s (%s) after %u blocks",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
tx_type_name(tx_type),
tx ? type_to_string(tmpctx, struct bitcoin_tx, tx):"IGNORING",
depth_required);
out->proposal = tal(out, struct proposed_resolution);
out->proposal->tx = tal_steal(out->proposal, tx);
out->proposal->depth_required = depth_required;
out->proposal->tx_type = tx_type;
if (depth_required == 0)
proposal_meets_depth(out);
}
static void propose_resolution_at_block(struct tracked_output *out,
const struct bitcoin_tx *tx,
unsigned int block_required,
enum tx_type tx_type)
{
u32 depth;
/* Expiry could be in the past! */
if (block_required < out->tx_blockheight)
depth = 0;
else /* Note that out->tx_blockheight is already at depth 1 */
depth = block_required - out->tx_blockheight + 1;
propose_resolution(out, tx, depth, tx_type);
}
static bool is_valid_sig(const u8 *e)
{
struct bitcoin_signature sig;
return signature_from_der(e, tal_count(e), &sig);
}
/* We ignore things which look like signatures. */
static bool input_similar(const struct wally_tx_input *i1,
const struct wally_tx_input *i2)
{
u8 *s1, *s2;
if (!memeq(i1->txhash, WALLY_TXHASH_LEN, i2->txhash, WALLY_TXHASH_LEN))
return false;
if (i1->index != i2->index)
return false;
if (!scripteq(i1->script, i2->script))
return false;
if (i1->sequence != i2->sequence)
return false;
if (i1->witness->num_items != i2->witness->num_items)
return false;
for (size_t i = 0; i < i1->witness->num_items; i++) {
/* Need to wrap these in `tal_arr`s since the primitives
* except to be able to call tal_bytelen on them */
s1 = tal_dup_arr(tmpctx, u8, i1->witness->items[i].witness,
i1->witness->items[i].witness_len, 0);
s2 = tal_dup_arr(tmpctx, u8, i2->witness->items[i].witness,
i2->witness->items[i].witness_len, 0);
if (scripteq(s1, s2))
continue;
if (is_valid_sig(s1) && is_valid_sig(s2))
continue;
return false;
}
return true;
}
/* This simple case: true if this was resolved by our proposal. */
static bool resolved_by_proposal(struct tracked_output *out,
const struct bitcoin_tx *tx)
{
/* If there's no TX associated, it's not us. */
if (!out->proposal->tx)
return false;
/* Our proposal can change as feerates change. Input
* comparison (ignoring signatures) works pretty well.
*
* FIXME: Better would be to compare outputs, but they weren't
* saved to db correctly until now. (COMPAT_V052)
*/
if (tx->wtx->num_inputs != out->proposal->tx->wtx->num_inputs)
return false;
for (size_t i = 0; i < tx->wtx->num_inputs; i++) {
if (!input_similar(&tx->wtx->inputs[i], &out->proposal->tx->wtx->inputs[i]))
return false;
}
out->resolved = tal(out, struct resolution);
bitcoin_txid(tx, &out->resolved->txid);
status_debug("Resolved %s/%s by our proposal %s (%s)",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
tx_type_name(out->proposal->tx_type),
type_to_string(tmpctx, struct bitcoin_txid,
&out->resolved->txid));
out->resolved->depth = 0;
out->resolved->tx_type = out->proposal->tx_type;
return true;
}
/* Otherwise, we figure out what happened and then call this. */
static void resolved_by_other(struct tracked_output *out,
const struct bitcoin_txid *txid,
enum tx_type tx_type)
{
out->resolved = tal(out, struct resolution);
out->resolved->txid = *txid;
out->resolved->depth = 0;
out->resolved->tx_type = tx_type;
status_debug("Resolved %s/%s by %s (%s)",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
tx_type_name(tx_type),
type_to_string(tmpctx, struct bitcoin_txid, txid));
}
static void unknown_spend(struct tracked_output *out,
const struct bitcoin_tx *tx)
{
out->resolved = tal(out, struct resolution);
bitcoin_txid(tx, &out->resolved->txid);
out->resolved->depth = 0;
out->resolved->tx_type = UNKNOWN_TXTYPE;
status_broken("Unknown spend of %s/%s by %s",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
type_to_string(tmpctx, struct bitcoin_tx, tx));
}
static u64 unmask_commit_number(const struct bitcoin_tx *tx,
enum side funder,
const struct pubkey *local_payment_basepoint,
const struct pubkey *remote_payment_basepoint)
{
u64 obscurer;
const struct pubkey *keys[NUM_SIDES];
keys[LOCAL] = local_payment_basepoint;
keys[REMOTE] = remote_payment_basepoint;
/* BOLT #3:
*
* The 48-bit commitment number is obscured by `XOR` with the lower 48 bits of...
*/
obscurer = commit_number_obscurer(keys[funder], keys[!funder]);
/* BOLT #3:
*
* * locktime: upper 8 bits are 0x20, lower 24 bits are the lower 24 bits of the obscured commitment number
*...
* * `txin[0]` sequence: upper 8 bits are 0x80, lower 24 bits are upper 24 bits of the obscured commitment number
*/
return ((tx->wtx->locktime & 0x00FFFFFF)
| (tx->wtx->inputs[0].sequence & (u64)0x00FFFFFF) << 24)
^ obscurer;
}
static bool is_mutual_close(const struct bitcoin_tx *tx,
const u8 *local_scriptpubkey,
const u8 *remote_scriptpubkey)
{
size_t i;
bool local_matched = false, remote_matched = false;
for (i = 0; i < tx->wtx->num_outputs; i++) {
const u8 *script = bitcoin_tx_output_get_script(tmpctx, tx, i);
/* To be paranoid, we only let each one match once. */
if (scripteq(script, local_scriptpubkey)
&& !local_matched)
local_matched = true;
else if (scripteq(script, remote_scriptpubkey)
&& !remote_matched)
remote_matched = true;
else
return false;
}
return true;
}
/* We only ever send out one, so matching it is easy. */
static bool is_local_commitment(const struct bitcoin_txid *txid,
const struct bitcoin_txid *our_broadcast_txid)
{
return bitcoin_txid_eq(txid, our_broadcast_txid);
}
/* BOLT #5:
*
* Outputs that are *resolved* are considered *irrevocably resolved*
* once the remote's *resolving* transaction is included in a block at least 100
* deep, on the most-work blockchain.
*/
static size_t num_not_irrevocably_resolved(struct tracked_output **outs)
{
size_t i, num = 0;
for (i = 0; i < tal_count(outs); i++) {
if (!outs[i]->resolved || outs[i]->resolved->depth < 100)
num++;
}
return num;
}
static u32 prop_blockheight(const struct tracked_output *out)
{
return out->tx_blockheight + out->proposal->depth_required;
}
static void billboard_update(struct tracked_output **outs)
{
const struct tracked_output *best = NULL;
/* Highest priority is to report on proposals we have */
for (size_t i = 0; i < tal_count(outs); i++) {
if (!outs[i]->proposal || outs[i]->resolved)
continue;
if (!best || prop_blockheight(outs[i]) < prop_blockheight(best))
best = outs[i];
}
if (best) {
/* If we've broadcast and not seen yet, this happens */
if (best->proposal->depth_required <= best->depth) {
peer_billboard(false,
"%u outputs unresolved: waiting confirmation that we spent %s (%s:%u) using %s",
num_not_irrevocably_resolved(outs),
output_type_name(best->output_type),
type_to_string(tmpctx, struct bitcoin_txid,
&best->txid),
best->outnum,
tx_type_name(best->proposal->tx_type));
} else {
peer_billboard(false,
"%u outputs unresolved: in %u blocks will spend %s (%s:%u) using %s",
num_not_irrevocably_resolved(outs),
best->proposal->depth_required - best->depth,
output_type_name(best->output_type),
type_to_string(tmpctx, struct bitcoin_txid,
&best->txid),
best->outnum,
tx_type_name(best->proposal->tx_type));
}
return;
}
/* Now, just report on the last thing we're waiting out. */
for (size_t i = 0; i < tal_count(outs); i++) {
/* FIXME: Can this happen? No proposal, no resolution? */
if (!outs[i]->resolved)
continue;
if (!best || outs[i]->resolved->depth < best->resolved->depth)
best = outs[i];
}
if (best) {
peer_billboard(false,
"All outputs resolved:"
" waiting %u more blocks before forgetting"
" channel",
best->resolved->depth < 100
? 100 - best->resolved->depth : 0);
return;
}
/* Not sure this can happen, but take last one (there must be one!) */
best = outs[tal_count(outs)-1];
peer_billboard(false, "%u outputs unresolved: %s is one (depth %u)",
num_not_irrevocably_resolved(outs),
output_type_name(best->output_type), best->depth);
}
static void unwatch_tx(const struct bitcoin_tx *tx)
{
u8 *msg;
struct bitcoin_txid txid;
bitcoin_txid(tx, &txid);
msg = towire_onchain_unwatch_tx(tx, &txid);
wire_sync_write(REQ_FD, take(msg));
}
static void handle_htlc_onchain_fulfill(struct tracked_output *out,
const struct bitcoin_tx *tx)
{
const u8 *witness_preimage;
struct preimage preimage;
struct sha256 sha;
struct ripemd160 ripemd;
/* Our HTLC, they filled (must be an HTLC-success tx). */
if (out->tx_type == THEIR_UNILATERAL) {
/* BOLT #3:
*
* ## HTLC-Timeout and HTLC-Success Transactions
*
* ... `txin[0]` witness stack: `0 <remotehtlcsig> <localhtlcsig>
* <payment_preimage>` for HTLC-success
*/
if (tx->wtx->inputs[0].witness->num_items != 5) /* +1 for wscript */
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"%s/%s spent with weird witness %zu",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
tx->wtx->inputs[0].witness->num_items);
witness_preimage =
bitcoin_tx_input_get_witness(tmpctx, tx, 0, 3);
} else if (out->tx_type == OUR_UNILATERAL) {
/* BOLT #3:
*
* The remote node can redeem the HTLC with the witness:
*
* <remotehtlcsig> <payment_preimage>
*/
if (tx->wtx->inputs[0].witness->num_items != 3) /* +1 for wscript */
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"%s/%s spent with weird witness %zu",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
tx->wtx->inputs[0].witness->num_items);
witness_preimage =
bitcoin_tx_input_get_witness(tmpctx, tx, 0, 1);
} else
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"onchain_fulfill for %s/%s?",
tx_type_name(out->tx_type),
output_type_name(out->output_type));
if (tal_count(witness_preimage) != sizeof(preimage))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"%s/%s spent with bad witness length %zu",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
tal_count(witness_preimage));
memcpy(&preimage, witness_preimage, sizeof(preimage));
sha256(&sha, &preimage, sizeof(preimage));
ripemd160(&ripemd, &sha, sizeof(sha));
if (!ripemd160_eq(&ripemd, &out->htlc.ripemd))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"%s/%s spent with bad preimage %s (ripemd not %s)",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
type_to_string(tmpctx, struct preimage, &preimage),
type_to_string(tmpctx, struct ripemd160,
&out->htlc.ripemd));
/* Tell master we found a preimage. */
status_debug("%s/%s gave us preimage %s",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
type_to_string(tmpctx, struct preimage, &preimage));
wire_sync_write(REQ_FD,
take(towire_onchain_extracted_preimage(NULL,
&preimage)));
}
static void resolve_htlc_tx(const struct chainparams *chainparams,
struct tracked_output ***outs,
size_t out_index,
const struct bitcoin_tx *htlc_tx,
const struct bitcoin_txid *htlc_txid,
u32 tx_blockheight)
{
struct tracked_output *out;
struct bitcoin_tx *tx;
struct amount_sat amt;
enum tx_type tx_type = OUR_DELAYED_RETURN_TO_WALLET;
u8 *wscript = bitcoin_wscript_htlc_tx(htlc_tx, to_self_delay[LOCAL],
&keyset->self_revocation_key,
&keyset->self_delayed_payment_key);
/* BOLT #5:
*
* - SHOULD resolve the HTLC-timeout transaction by spending it to
* a convenient address...
* - MUST wait until the `OP_CHECKSEQUENCEVERIFY` delay has passed
* (as specified by the remote node's `open_channel`
* `to_self_delay` field) before spending that HTLC-timeout
* output.
*/
amt = bitcoin_tx_output_get_amount(htlc_tx, 0);
out = new_tracked_output(chainparams, outs, htlc_txid, tx_blockheight,
(*outs)[out_index]->resolved->tx_type,
0, amt,
DELAYED_OUTPUT_TO_US,
NULL, NULL, NULL);
/* BOLT #3:
*
* ## HTLC-Timeout and HTLC-Success Transactions
*
* These HTLC transactions are almost identical, except the
* HTLC-timeout transaction is timelocked.
*
* ... to collect the output, the local node uses an input with
* nSequence `to_self_delay` and a witness stack `<local_delayedsig>
* 0`
*/
tx = tx_to_us(*outs, delayed_payment_to_us,
out, to_self_delay[LOCAL], 0, NULL, 0,
wscript,
&tx_type);
propose_resolution(out, tx, to_self_delay[LOCAL], tx_type);
}
/* BOLT #5:
*
* - MUST *resolve* the _remote node's HTLC-timeout transaction_ by spending it
* using the revocation private key.
* - MUST *resolve* the _remote node's HTLC-success transaction_ by spending it
* using the revocation private key.
*/
static void steal_htlc_tx(struct tracked_output *out)
{
struct bitcoin_tx *tx;
enum tx_type tx_type = OUR_PENALTY_TX;
/* BOLT #3:
*
* To spend this via penalty, the remote node uses a witness stack
* `<revocationsig> 1`
*/
tx = tx_to_us(out, penalty_to_us, out, 0xFFFFFFFF, 0,
&ONE, sizeof(ONE),
out->wscript,
&tx_type);
propose_resolution(out, tx, 0, tx_type);
}
static void onchain_transaction_annotate(const struct bitcoin_txid *txid,
enum wallet_tx_type type)
{
u8 *msg = towire_onchain_transaction_annotate(tmpctx, txid, type);
wire_sync_write(REQ_FD, take(msg));
}
/* An output has been spent: see if it resolves something we care about. */
static void output_spent(const struct chainparams *chainparams,
struct tracked_output ***outs,
const struct bitcoin_tx *tx,
u32 input_num,
u32 tx_blockheight)
{
struct bitcoin_txid txid, tmptxid, spendertxid;
bitcoin_txid(tx, &txid);
bitcoin_txid(tx, &spendertxid);
for (size_t i = 0; i < tal_count(*outs); i++) {
struct tracked_output *out = (*outs)[i];
if (out->resolved)
continue;
if (tx->wtx->inputs[input_num].index != out->outnum)
continue;
bitcoin_tx_input_get_txid(tx, input_num, &tmptxid);
if (!bitcoin_txid_eq(&tmptxid, &out->txid))
continue;
/* Was this our resolution? */
if (resolved_by_proposal(out, tx)) {
/* If it's our htlc tx, we need to resolve that, too. */
if (out->resolved->tx_type == OUR_HTLC_SUCCESS_TX
|| out->resolved->tx_type == OUR_HTLC_TIMEOUT_TX)
resolve_htlc_tx(chainparams, outs, i, tx, &txid,
tx_blockheight);
return;
}
switch (out->output_type) {
case OUTPUT_TO_US:
case DELAYED_OUTPUT_TO_US:
unknown_spend(out, tx);
break;
case THEIR_HTLC:
if (out->tx_type == THEIR_REVOKED_UNILATERAL) {
steal_htlc_tx(out);
} else {
/* We ignore this timeout tx, since we should
* resolve by ignoring once we reach depth. */
onchain_transaction_annotate(
&spendertxid,
TX_CHANNEL_HTLC_TIMEOUT | TX_THEIRS);
}
break;
case OUR_HTLC:
/* The only way they can spend this: fulfill; even
* if it's revoked: */
/* BOLT #5:
*
* ## HTLC Output Handling: Local Commitment, Local Offers
*...
* - MUST extract the payment preimage from the
* transaction input witness.
*...
* ## HTLC Output Handling: Remote Commitment, Local Offers
*...
* - MUST extract the payment preimage from the
* HTLC-success transaction input witness.
*/
handle_htlc_onchain_fulfill(out, tx);
if (out->tx_type == THEIR_REVOKED_UNILATERAL)
steal_htlc_tx(out);
else {
/* BOLT #5:
*
* ## HTLC Output Handling: Local Commitment,
* Local Offers
*...
* - if the commitment transaction HTLC output
* is spent using the payment preimage, the
* output is considered *irrevocably resolved*
*/
ignore_output(out);
onchain_transaction_annotate(
&spendertxid,
TX_CHANNEL_HTLC_SUCCESS | TX_THEIRS);
}
break;
case FUNDING_OUTPUT:
/* Master should be restarting us, as this implies
* that our old tx was unspent. */
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Funding output spent again!");
/* Um, we don't track these! */
case OUTPUT_TO_THEM:
case DELAYED_OUTPUT_TO_THEM:
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Tracked spend of %s/%s?",
tx_type_name(out->tx_type),
output_type_name(out->output_type));
}
return;
}
bitcoin_tx_input_get_txid(tx, input_num, &txid);
/* Not interesting to us, so unwatch the tx and all its outputs */
status_debug("Notified about tx %s output %u spend, but we don't care",
type_to_string(tmpctx, struct bitcoin_txid, &txid),
tx->wtx->inputs[input_num].index);
unwatch_tx(tx);
}
static void update_resolution_depth(struct tracked_output *out, u32 depth)
{
bool reached_reasonable_depth;
status_debug("%s/%s->%s depth %u",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
tx_type_name(out->resolved->tx_type),
depth);
/* We only set this once. */
reached_reasonable_depth = (out->resolved->depth < reasonable_depth
&& depth >= reasonable_depth);
/* 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.
* - once the resolving transaction has reached reasonable depth:
* - MUST fail the corresponding incoming HTLC (if any).
*/
if ((out->resolved->tx_type == OUR_HTLC_TIMEOUT_TX
|| out->resolved->tx_type == OUR_HTLC_TIMEOUT_TO_US)
&& reached_reasonable_depth) {
u8 *msg;
status_debug("%s/%s reached reasonable depth %u",
tx_type_name(out->tx_type),
output_type_name(out->output_type),
depth);
msg = towire_onchain_htlc_timeout(out, &out->htlc);
wire_sync_write(REQ_FD, take(msg));
}
out->resolved->depth = depth;
}
static void tx_new_depth(struct tracked_output **outs,
const struct bitcoin_txid *txid, u32 depth)
{
size_t i;
/* Special handling for commitment tx reaching depth */
if (bitcoin_txid_eq(&outs[0]->resolved->txid, txid)
&& depth >= reasonable_depth
&& missing_htlc_msgs) {
status_debug("Sending %zu missing htlc messages",
tal_count(missing_htlc_msgs));
for (i = 0; i < tal_count(missing_htlc_msgs); i++)
wire_sync_write(REQ_FD, missing_htlc_msgs[i]);
/* Don't do it again. */
missing_htlc_msgs = tal_free(missing_htlc_msgs);
}
for (i = 0; i < tal_count(outs); i++) {
/* Update output depth. */
if (bitcoin_txid_eq(&outs[i]->txid, txid))
outs[i]->depth = depth;
/* Is this tx resolving an output? */
if (outs[i]->resolved) {
if (bitcoin_txid_eq(&outs[i]->resolved->txid, txid)) {
update_resolution_depth(outs[i], depth);
}
continue;
}
/* Otherwise, is this something we have a pending
* resolution for? */
if (outs[i]->proposal
&& bitcoin_txid_eq(&outs[i]->txid, txid)
&& depth >= outs[i]->proposal->depth_required) {
proposal_meets_depth(outs[i]);
}
}
}
/* 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 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.
*...
* ## HTLC Output Handling: Remote Commitment, Remote Offers
*...
* A local node:
* - if it receives (or already possesses) a payment preimage for an unresolved
* HTLC output that it was offered AND for which it has committed to an
* outgoing HTLC:
* - MUST *resolve* the output by spending it to a convenient address.
* - otherwise:
* - if the remote node is NOT irrevocably committed to the HTLC:
* - MUST NOT *resolve* the output by spending it.
*/
/* Master makes sure we only get told preimages once other node is committed. */
static void handle_preimage(const struct chainparams *chainparams,
struct tracked_output **outs,
const struct preimage *preimage)
{
size_t i;
struct sha256 sha;
struct ripemd160 ripemd;
u8 **witness;
sha256(&sha, preimage, sizeof(*preimage));
ripemd160(&ripemd, &sha, sizeof(sha));
for (i = 0; i < tal_count(outs); i++) {
struct bitcoin_tx *tx;
struct bitcoin_signature sig;
if (outs[i]->output_type != THEIR_HTLC)
continue;
if (!ripemd160_eq(&outs[i]->htlc.ripemd, &ripemd))
continue;
/* Too late? */
if (outs[i]->resolved) {
status_broken("HTLC already resolved by %s"
" when we found preimage",
tx_type_name(outs[i]->resolved->tx_type));
return;
}
/* Discard any previous resolution. Could be a timeout,
* could be due to multiple identical rhashes in tx. */
outs[i]->proposal = tal_free(outs[i]->proposal);
/* BOLT #5:
*
*
* ## HTLC Output Handling: Local Commitment, Remote Offers
*...
* 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.
*/
if (outs[i]->remote_htlc_sig) {
struct amount_msat htlc_amount;
if (!amount_sat_to_msat(&htlc_amount, outs[i]->sat))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Overflow in output %zu %s",
i,
type_to_string(tmpctx,
struct amount_sat,
&outs[i]->sat));
tx = htlc_success_tx(outs[i],
chainparams,
&outs[i]->txid,
outs[i]->outnum,
htlc_amount,
to_self_delay[LOCAL],
0,
keyset);
set_htlc_success_fee(tx, outs[i]->remote_htlc_sig,
outs[i]->wscript);
hsm_sign_local_htlc_tx(tx, outs[i]->wscript, &sig);
witness = bitcoin_witness_htlc_success_tx(
tx, &sig, outs[i]->remote_htlc_sig, preimage,
outs[i]->wscript);
bitcoin_tx_input_set_witness(tx, 0, take(witness));
propose_resolution(outs[i], tx, 0, OUR_HTLC_SUCCESS_TX);
} else {
enum tx_type tx_type = THEIR_HTLC_FULFILL_TO_US;
/* BOLT #5:
*
* ## HTLC Output Handling: Remote Commitment, Remote
* Offers
*...
* A local node:
* - if it receives (or already possesses) a payment
* preimage for an unresolved HTLC output that it was
* offered AND for which it has committed to an
* outgoing HTLC:
* - MUST *resolve* the output by spending it to a
* convenient address.
*/
tx = tx_to_us(outs[i], remote_htlc_to_us,
outs[i], 0, 0,
preimage, sizeof(*preimage),
outs[i]->wscript,
&tx_type);
propose_resolution(outs[i], tx, 0, tx_type);
}
}
}
#if DEVELOPER
static void memleak_remove_globals(struct htable *memtable, const tal_t *topctx)
{
/* memleak_scan_region is overkill if these are simple pointers to
* objects which don't contain pointers, but it works. */
if (keyset)
memleak_scan_region(memtable, keyset, sizeof(*keyset));
if (remote_per_commitment_point)
memleak_scan_region(memtable, remote_per_commitment_point,
sizeof(*remote_per_commitment_point));
if (remote_per_commitment_secret)
memleak_scan_region(memtable, remote_per_commitment_secret,
sizeof(*remote_per_commitment_secret));
/* top-level context args */
memleak_scan_region(memtable, topctx, 0);
memleak_scan_region(memtable, missing_htlc_msgs,
tal_bytelen(missing_htlc_msgs));
}
static bool handle_dev_memleak(struct tracked_output **outs, const u8 *msg)
{
struct htable *memtable;
bool found_leak;
if (!fromwire_onchain_dev_memleak(msg))
return false;
memtable = memleak_enter_allocations(tmpctx, msg, msg);
/* Top-level context is parent of outs */
memleak_remove_globals(memtable, tal_parent(outs));
memleak_remove_referenced(memtable, outs);
found_leak = dump_memleak(memtable);
wire_sync_write(REQ_FD,
take(towire_onchain_dev_memleak_reply(NULL,
found_leak)));
return true;
}
#else
static bool handle_dev_memleak(struct tracked_output **outs, const u8 *msg)
{
return false;
}
#endif /* !DEVELOPER */
/* BOLT #5:
*
* A node:
* - once it has broadcast a funding transaction OR sent a commitment signature
* for a commitment transaction that contains an HTLC output:
* - until all outputs are *irrevocably resolved*:
* - MUST monitor the blockchain for transactions that spend any output that
* is NOT *irrevocably resolved*.
*/
static void wait_for_resolved(const struct chainparams *chainparams,
struct tracked_output **outs)
{
billboard_update(outs);
while (num_not_irrevocably_resolved(outs) != 0) {
u8 *msg = wire_sync_read(outs, REQ_FD);
struct bitcoin_txid txid;
struct bitcoin_tx *tx;
u32 input_num, depth, tx_blockheight;
struct preimage preimage;
status_debug("Got new message %s",
onchain_wire_type_name(fromwire_peektype(msg)));
if (fromwire_onchain_depth(msg, &txid, &depth))
tx_new_depth(outs, &txid, depth);
else if (fromwire_onchain_spent(msg, msg, &tx, &input_num,
&tx_blockheight)) {
tx->chainparams = chainparams;
output_spent(chainparams, &outs, tx, input_num, tx_blockheight);
} else if (fromwire_onchain_known_preimage(msg, &preimage))
handle_preimage(chainparams, outs, &preimage);
else if (!handle_dev_memleak(outs, msg))
master_badmsg(-1, msg);
billboard_update(outs);
tal_free(msg);
clean_tmpctx();
}
wire_sync_write(REQ_FD,
take(towire_onchain_all_irrevocably_resolved(outs)));
}
static void init_reply(const char *what)
{
/* Send init_reply first, so billboard gets credited to ONCHAIND */
wire_sync_write(REQ_FD, take(towire_onchain_init_reply(NULL)));
peer_billboard(true, what);
}
static void handle_mutual_close(const struct chainparams *chainparams,
const struct bitcoin_txid *txid,
struct tracked_output **outs)
{
init_reply("Tracking mutual close transaction");
onchain_transaction_annotate(txid, TX_CHANNEL_CLOSE);
/* BOLT #5:
*
* A closing transaction *resolves* the funding transaction output.
*
* In the case of a mutual close, a node need not do anything else, as it has
* already agreed to the output, which is sent to its specified `scriptpubkey`
*/
resolved_by_other(outs[0], txid, MUTUAL_CLOSE);
wait_for_resolved(chainparams, outs);
}
static u8 **derive_htlc_scripts(const struct htlc_stub *htlcs, enum side side)
{
size_t i;
u8 **htlc_scripts = tal_arr(htlcs, u8 *, tal_count(htlcs));
for (i = 0; i < tal_count(htlcs); i++) {
if (htlcs[i].owner == side)
htlc_scripts[i] = htlc_offered_wscript(htlc_scripts,
&htlcs[i].ripemd,
keyset);
else {
/* FIXME: remove abs_locktime */
struct abs_locktime ltime;
if (!blocks_to_abs_locktime(htlcs[i].cltv_expiry,
&ltime))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not convert cltv_expiry %u to locktime",
htlcs[i].cltv_expiry);
htlc_scripts[i] = htlc_received_wscript(htlc_scripts,
&htlcs[i].ripemd,
&ltime,
keyset);
}
}
return htlc_scripts;
}
static size_t resolve_our_htlc_ourcommit(const struct chainparams *chainparams,
struct tracked_output *out,
const size_t *matches,
const struct htlc_stub *htlcs,
u8 **htlc_scripts)
{
struct bitcoin_tx *tx = NULL;
struct bitcoin_signature localsig;
size_t i;
struct amount_msat htlc_amount;
u8 **witness;
if (!amount_sat_to_msat(&htlc_amount, out->sat))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Overflow in our_htlc output %s",
type_to_string(tmpctx, struct amount_sat,
&out->sat));
assert(tal_count(matches));
/* These htlcs are all possibilities, but signature will only match
* one with the correct cltv: check which that is. */
for (i = 0; i < tal_count(matches); i++) {
/* BOLT #5:
*
* ## HTLC Output Handling: Local Commitment, Local Offers
* ...
* - 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.
*/
tx = htlc_timeout_tx(tmpctx, chainparams,
&out->txid, out->outnum,
htlc_amount,
htlcs[matches[i]].cltv_expiry,
to_self_delay[LOCAL], 0, keyset);
if (set_htlc_timeout_fee(tx, out->remote_htlc_sig,
htlc_scripts[matches[i]]))
break;
}
/* Since there's been trouble with this before, we go to some length
* to give details here! */
if (i == tal_count(matches)) {
char *cltvs, *wscripts;
cltvs = tal_fmt(tmpctx, "%u", htlcs[matches[0]].cltv_expiry);
wscripts = tal_hex(tmpctx, htlc_scripts[matches[0]]);
for (i = 1; i < tal_count(matches); i++) {
tal_append_fmt(&cltvs, "/%u",
htlcs[matches[i]].cltv_expiry);
tal_append_fmt(&wscripts, "/%s",
tal_hex(tmpctx, htlc_scripts[matches[i]]));
}
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"No valid signature found for %zu htlc_timeout_txs"
" feerate %u-%u,"
" last tx %s, input %s, signature %s,"
" cltvs %s wscripts %s",
tal_count(matches),
min_possible_feerate, max_possible_feerate,
type_to_string(tmpctx, struct bitcoin_tx, tx),
type_to_string(tmpctx, struct amount_sat,
&out->sat),
type_to_string(tmpctx, struct bitcoin_signature,
out->remote_htlc_sig),
cltvs, wscripts);
}
hsm_sign_local_htlc_tx(tx, htlc_scripts[matches[i]], &localsig);
witness = bitcoin_witness_htlc_timeout_tx(tx, &localsig,
out->remote_htlc_sig,
htlc_scripts[matches[i]]);
bitcoin_tx_input_set_witness(tx, 0, take(witness));
/* Steals tx onto out */
propose_resolution_at_block(out, tx, htlcs[matches[i]].cltv_expiry,
OUR_HTLC_TIMEOUT_TX);
return matches[i];
}
/* wscript for *received* htlcs (ie. our htlcs in their commit tx, or their
* htlcs in our commit tx) includes cltv, so they must be the same for all
* matching htlcs. Unless, of course, they've found a sha256 clash. */
static u32 matches_cltv(const size_t *matches,
const struct htlc_stub *htlcs)
{
for (size_t i = 1; i < tal_count(matches); i++) {
assert(matches[i] < tal_count(htlcs));
assert(htlcs[matches[i]].cltv_expiry
== htlcs[matches[i-1]].cltv_expiry);
}
return htlcs[matches[0]].cltv_expiry;
}
static size_t resolve_our_htlc_theircommit(struct tracked_output *out,
const size_t *matches,
const struct htlc_stub *htlcs,
u8 **htlc_scripts)
{
struct bitcoin_tx *tx;
enum tx_type tx_type = OUR_HTLC_TIMEOUT_TO_US;
u32 cltv_expiry = matches_cltv(matches, htlcs);
/* BOLT #5:
*
* ## HTLC Output Handling: Remote Commitment, Local Offers
* ...
*
* - if the commitment transaction HTLC output has *timed out* AND NOT
* been *resolved*:
* - MUST *resolve* the output, by spending it to a convenient
* address.
*/
tx = tx_to_us(out, remote_htlc_to_us,
out, 0, cltv_expiry, NULL, 0,
htlc_scripts[matches[0]],
&tx_type);
propose_resolution_at_block(out, tx, cltv_expiry, tx_type);
/* They're all equivalent: might as well use first one. */
return matches[0];
}
/* Returns which htlcs it chose to use of matches[] */
static size_t resolve_their_htlc(struct tracked_output *out,
const size_t *matches,
const struct htlc_stub *htlcs,
u8 **htlc_scripts)
{
size_t which_htlc;
/* BOLT #5:
*
* ## HTLC Output Handling: Remote Commitment, Remote Offers
*...
* ### Requirements
*...
* If not otherwise resolved, once the HTLC output has expired, it is
* considered *irrevocably resolved*.
*/
/* BOLT #5:
*
* ## HTLC Output Handling: Local Commitment, Remote Offers
*...
* ### Requirements
*...
* If not otherwise resolved, once the HTLC output has expired, it is
* considered *irrevocably resolved*.
*/
/* The two cases are identical as far as default handling goes.
* But in the remote commitment / remote offer (ie. caller is
* handle_their_unilateral), htlcs which match may have different cltvs.
* So wait until the worst case (largest HTLC). */
assert(tal_count(matches));
which_htlc = matches[0];
for (size_t i = 1; i < tal_count(matches); i++) {
if (htlcs[matches[i]].cltv_expiry > htlcs[which_htlc].cltv_expiry)
which_htlc = matches[i];
}
/* If we hit timeout depth, resolve by ignoring. */
propose_resolution_at_block(out, NULL, htlcs[which_htlc].cltv_expiry,
THEIR_HTLC_TIMEOUT_TO_THEM);
return which_htlc;
}
/* Return tal_arr of htlc indexes. */
static const size_t *match_htlc_output(const tal_t *ctx,
const struct bitcoin_tx *tx,
unsigned int outnum,
u8 **htlc_scripts)
{
size_t *matches = tal_arr(ctx, size_t, 0);
const u8 *script = bitcoin_tx_output_get_script(tmpctx, tx, outnum);
/* Must be a p2wsh output */
if (!is_p2wsh(script, NULL))
return matches;
for (size_t i = 0; i < tal_count(htlc_scripts); i++) {
struct sha256 sha;
if (!htlc_scripts[i])
continue;
sha256(&sha, htlc_scripts[i], tal_count(htlc_scripts[i]));
if (memeq(script + 2, tal_count(script) - 2, &sha, sizeof(sha)))
tal_arr_expand(&matches, i);
}
return matches;
}
/* They must all be in the same direction, since the scripts are different for
* each dir. Unless, of course, they've found a sha256 clash. */
static enum side matches_direction(const size_t *matches,
const struct htlc_stub *htlcs)
{
for (size_t i = 1; i < tal_count(matches); i++) {
assert(matches[i] < tal_count(htlcs));
assert(htlcs[matches[i]].owner == htlcs[matches[i-1]].owner);
}
return htlcs[matches[0]].owner;
}
/* Tell master about any we didn't use, if it wants to know. */
static void note_missing_htlcs(u8 **htlc_scripts,
const struct htlc_stub *htlcs,
const bool *tell_if_missing,
const bool *tell_immediately)
{
for (size_t i = 0; i < tal_count(htlcs); i++) {
u8 *msg;
/* Used. */
if (!htlc_scripts[i])
continue;
/* Doesn't care. */
if (!tell_if_missing[i])
continue;
msg = towire_onchain_missing_htlc_output(missing_htlc_msgs,
&htlcs[i]);
if (tell_immediately[i])
wire_sync_write(REQ_FD, take(msg));
else
tal_arr_expand(&missing_htlc_msgs, msg);
}
}
static void handle_our_unilateral(const struct bitcoin_tx *tx,
u32 tx_blockheight,
const struct bitcoin_txid *txid,
const struct basepoints basepoints[NUM_SIDES],
const struct htlc_stub *htlcs,
const bool *tell_if_missing,
const bool *tell_immediately,
const secp256k1_ecdsa_signature *remote_htlc_sigs,
struct tracked_output **outs)
{
u8 **htlc_scripts;
u8 *local_wscript, *script[NUM_SIDES];
struct pubkey local_per_commitment_point;
struct keyset *ks;
size_t i;
init_reply("Tracking our own unilateral close");
onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL);
/* BOLT #5:
*
* In this case, a node discovers its *local commitment transaction*,
* which *resolves* the funding transaction output.
*/
resolved_by_other(outs[0], txid, OUR_UNILATERAL);
/* Figure out what delayed to-us output looks like */
hsm_get_per_commitment_point(&local_per_commitment_point);
/* keyset is const, we need a non-const ptr to set it up */
keyset = ks = tal(tx, struct keyset);
if (!derive_keyset(&local_per_commitment_point,
&basepoints[LOCAL],
&basepoints[REMOTE],
option_static_remotekey,
ks))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Deriving keyset for %"PRIu64, commit_num);
status_debug("Deconstructing unilateral tx: %"PRIu64
" using keyset: "
" self_revocation_key: %s"
" self_delayed_payment_key: %s"
" self_payment_key: %s"
" other_payment_key: %s"
" self_htlc_key: %s"
" other_htlc_key: %s",
commit_num,
type_to_string(tmpctx, struct pubkey,
&keyset->self_revocation_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_delayed_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->other_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_htlc_key),
type_to_string(tmpctx, struct pubkey,
&keyset->other_htlc_key));
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);
/* Figure out what direct to-them output looks like. */
script[REMOTE] = scriptpubkey_p2wpkh(tmpctx, &keyset->other_payment_key);
/* Calculate all the HTLC scripts so we can match them */
htlc_scripts = derive_htlc_scripts(htlcs, LOCAL);
status_debug("Script to-me: %u: %s (%s)",
to_self_delay[LOCAL],
tal_hex(tmpctx, script[LOCAL]),
tal_hex(tmpctx, local_wscript));
status_debug("Script to-them: %s",
tal_hex(tmpctx, script[REMOTE]));
for (i = 0; i < tx->wtx->num_outputs; i++) {
status_debug("Output %zu: %s", i,
tal_hex(tmpctx, bitcoin_tx_output_get_script(
tmpctx, tx, i)));
}
for (i = 0; i < tx->wtx->num_outputs; i++) {
struct tracked_output *out;
const size_t *matches;
size_t which_htlc;
const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i);
struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i);
if (script[LOCAL]
&& scripteq(oscript, script[LOCAL])) {
struct bitcoin_tx *to_us;
enum tx_type tx_type = OUR_DELAYED_RETURN_TO_WALLET;
/* BOLT #5:
*
* A node:
* - upon discovering its *local commitment
* transaction*:
* - SHOULD spend the `to_local` output to a
* convenient address.
* - MUST wait until the `OP_CHECKSEQUENCEVERIFY`
* delay has passed (as specified by the remote
* node's `to_self_delay` field) before spending
* the output.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid, tx_blockheight,
OUR_UNILATERAL, i,
amt,
DELAYED_OUTPUT_TO_US,
NULL, NULL, NULL);
/* BOLT #3:
*
* The output is spent by a transaction with
* `nSequence` field set to `to_self_delay` (which can
* only be valid after that duration has passed) and
* witness:
*
* <local_delayedsig> 0
*/
to_us = tx_to_us(out, delayed_payment_to_us,
out, to_self_delay[LOCAL], 0,
NULL, 0,
local_wscript,
&tx_type);
/* BOLT #5:
*
* Note: if the output is spent (as recommended), the
* output is *resolved* by the spending transaction
*/
propose_resolution(out, to_us, to_self_delay[LOCAL],
tx_type);
script[LOCAL] = NULL;
continue;
}
if (script[REMOTE]
&& scripteq(oscript, script[REMOTE])) {
/* BOLT #5:
*
* - MAY ignore the `to_remote` output.
* - Note: No action is required by the local
* node, as `to_remote` is considered *resolved*
* by the commitment transaction itself.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid, tx_blockheight,
OUR_UNILATERAL, i,
amt,
OUTPUT_TO_THEM,
NULL, NULL, NULL);
ignore_output(out);
script[REMOTE] = NULL;
continue;
}
matches = match_htlc_output(tmpctx, tx, i, htlc_scripts);
/* FIXME: limp along when this happens! */
if (tal_count(matches) == 0) {
onchain_transaction_annotate(txid, TX_CHANNEL_PENALTY | TX_THEIRS);
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not find resolution for output %zu",
i);
}
if (matches_direction(matches, htlcs) == LOCAL) {
/* BOLT #5:
*
* - MUST handle HTLCs offered by itself as specified
* in [HTLC Output Handling: Local Commitment,
* Local Offers]
*/
out = new_tracked_output(tx->chainparams,
&outs, txid,
tx_blockheight,
OUR_UNILATERAL, i,
amt,
OUR_HTLC,
NULL, NULL,
remote_htlc_sigs);
/* Tells us which htlc to use */
which_htlc = resolve_our_htlc_ourcommit(tx->chainparams,
out, matches,
htlcs,
htlc_scripts);
} else {
out = new_tracked_output(tx->chainparams,
&outs, txid,
tx_blockheight,
OUR_UNILATERAL, i,
amt,
THEIR_HTLC,
NULL, NULL,
remote_htlc_sigs);
/* BOLT #5:
*
* - MUST handle HTLCs offered by the remote node
* as specified in [HTLC Output Handling: Local
* Commitment, Remote Offers]
*/
/* Tells us which htlc to use */
which_htlc = resolve_their_htlc(out, matches, htlcs,
htlc_scripts);
}
out->htlc = htlcs[which_htlc];
out->wscript = tal_steal(out, htlc_scripts[which_htlc]);
/* Each of these consumes one HTLC signature */
remote_htlc_sigs++;
/* We've matched this HTLC, can't do again. */
htlc_scripts[which_htlc] = NULL;
}
note_missing_htlcs(htlc_scripts, htlcs,
tell_if_missing, tell_immediately);
wait_for_resolved(tx->chainparams, outs);
}
/* We produce individual penalty txs. It's less efficient, but avoids them
* using HTLC txs to block our penalties for long enough to pass the CSV
* delay */
static void steal_to_them_output(struct tracked_output *out)
{
u8 *wscript;
struct bitcoin_tx *tx;
enum tx_type tx_type = OUR_PENALTY_TX;
/* BOLT #3:
*
* If a revoked commitment transaction is published, the other party
* can spend this output immediately with the following witness:
*
* <revocation_sig> 1
*/
wscript = bitcoin_wscript_to_local(tmpctx, to_self_delay[REMOTE],
&keyset->self_revocation_key,
&keyset->self_delayed_payment_key);
tx = tx_to_us(tmpctx,
penalty_to_us,
out, 0xFFFFFFFF, 0,
&ONE, sizeof(ONE),
wscript,
&tx_type);
propose_resolution(out, tx, 0, tx_type);
}
static void steal_htlc(struct tracked_output *out)
{
struct bitcoin_tx *tx;
enum tx_type tx_type = OUR_PENALTY_TX;
u8 der[PUBKEY_CMPR_LEN];
/* BOLT #3:
*
* If a revoked commitment transaction is published, the remote node can
* spend this output immediately with the following witness:
*
* <revocation_sig> <revocationpubkey>
*/
pubkey_to_der(der, &keyset->self_revocation_key);
tx = tx_to_us(out,
penalty_to_us,
out, 0xFFFFFFFF, 0,
der, sizeof(der),
out->wscript,
&tx_type);
propose_resolution(out, tx, 0, tx_type);
}
/* Tell wallet that we have discovered a UTXO from a to-remote output,
* which it can spend with a little additional info we give here. */
static void tell_wallet_to_remote(const struct bitcoin_tx *tx,
unsigned int outnum,
const struct bitcoin_txid *txid,
u32 tx_blockheight,
const u8 *scriptpubkey,
const struct pubkey *per_commit_point,
bool option_static_remotekey)
{
struct amount_sat amt = bitcoin_tx_output_get_amount(tx, outnum);
/* A NULL per_commit_point is how we indicate the pubkey doesn't need
* changing. */
if (option_static_remotekey)
per_commit_point = NULL;
wire_sync_write(REQ_FD,
take(towire_onchain_add_utxo(NULL, txid, outnum,
per_commit_point,
amt,
tx_blockheight,
scriptpubkey)));
}
/* BOLT #5:
*
* If any node tries to cheat by broadcasting an outdated commitment
* transaction (any previous commitment transaction besides the most current
* one), the other node in the channel can use its revocation private key to
* claim all the funds from the channel's original funding transaction.
*/
static void handle_their_cheat(const struct bitcoin_tx *tx,
const struct bitcoin_txid *txid,
u32 tx_blockheight,
const struct secret *revocation_preimage,
const struct basepoints basepoints[NUM_SIDES],
const struct htlc_stub *htlcs,
const bool *tell_if_missing,
const bool *tell_immediately,
struct tracked_output **outs)
{
u8 **htlc_scripts;
u8 *remote_wscript, *script[NUM_SIDES];
struct keyset *ks;
struct pubkey *k;
size_t i;
init_reply("Tracking their illegal close: taking all funds");
onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL | TX_CHANNEL_CHEAT | TX_THEIRS);
/* BOLT #5:
*
* Once a node discovers a commitment transaction for which *it* has a
* revocation private key, the funding transaction output is *resolved*.
*/
resolved_by_other(outs[0], txid, THEIR_REVOKED_UNILATERAL);
/* FIXME: Types. */
BUILD_ASSERT(sizeof(struct secret) == sizeof(*revocation_preimage));
remote_per_commitment_secret = tal_dup(tx, struct secret,
(struct secret *)
revocation_preimage);
/* Need tmpvar for non-const. */
remote_per_commitment_point = k = tal(tx, struct pubkey);
if (!pubkey_from_secret(remote_per_commitment_secret, k))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Failed derive from per_commitment_secret %s",
type_to_string(tmpctx, struct secret,
remote_per_commitment_secret));
status_debug("Deriving keyset %"PRIu64
": per_commit_point=%s"
" self_payment_basepoint=%s"
" other_payment_basepoint=%s"
" self_htlc_basepoint=%s"
" other_htlc_basepoint=%s"
" self_delayed_basepoint=%s"
" other_revocation_basepoint=%s",
commit_num,
type_to_string(tmpctx, struct pubkey,
remote_per_commitment_point),
type_to_string(tmpctx, struct pubkey,
&basepoints[REMOTE].payment),
type_to_string(tmpctx, struct pubkey,
&basepoints[LOCAL].payment),
type_to_string(tmpctx, struct pubkey,
&basepoints[REMOTE].htlc),
type_to_string(tmpctx, struct pubkey,
&basepoints[LOCAL].htlc),
type_to_string(tmpctx, struct pubkey,
&basepoints[REMOTE].delayed_payment),
type_to_string(tmpctx, struct pubkey,
&basepoints[LOCAL].revocation));
/* keyset is const, we need a non-const ptr to set it up */
keyset = ks = tal(tx, struct keyset);
if (!derive_keyset(remote_per_commitment_point,
&basepoints[REMOTE],
&basepoints[LOCAL],
option_static_remotekey,
ks))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Deriving keyset for %"PRIu64, commit_num);
status_debug("Deconstructing revoked unilateral tx: %"PRIu64
" using keyset: "
" self_revocation_key: %s"
" self_delayed_payment_key: %s"
" self_payment_key: %s"
" other_payment_key: %s"
" self_htlc_key: %s"
" other_htlc_key: %s"
" (option_static_remotekey = %i)",
commit_num,
type_to_string(tmpctx, struct pubkey,
&keyset->self_revocation_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_delayed_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->other_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_htlc_key),
type_to_string(tmpctx, struct pubkey,
&keyset->other_htlc_key),
option_static_remotekey);
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);
/* Figure out what direct to-us output looks like. */
script[LOCAL] = scriptpubkey_p2wpkh(tmpctx, &keyset->other_payment_key);
/* Calculate all the HTLC scripts so we can match them */
htlc_scripts = derive_htlc_scripts(htlcs, REMOTE);
status_debug("Script to-them: %u: %s (%s)",
to_self_delay[REMOTE],
tal_hex(tmpctx, script[REMOTE]),
tal_hex(tmpctx, remote_wscript));
status_debug("Script to-me: %s",
tal_hex(tmpctx, script[LOCAL]));
for (i = 0; i < tx->wtx->num_outputs; i++) {
status_debug("Output %zu: %s", i,
tal_hex(tmpctx, bitcoin_tx_output_get_script(
tmpctx, tx, i)));
}
for (i = 0; i < tx->wtx->num_outputs; i++) {
struct tracked_output *out;
const size_t *matches;
size_t which_htlc;
const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i);
struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i);
if (script[LOCAL]
&& scripteq(oscript, script[LOCAL])) {
/* BOLT #5:
*
* - MAY take no action regarding the _local node's
* main output_, as this is a simple P2WPKH output
* to itself.
* - Note: this output is considered *resolved* by
* the commitment transaction itself.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid, tx_blockheight,
THEIR_REVOKED_UNILATERAL,
i, amt,
OUTPUT_TO_US, NULL, NULL, NULL);
ignore_output(out);
tell_wallet_to_remote(tx, i, txid,
tx_blockheight,
script[LOCAL],
remote_per_commitment_point,
option_static_remotekey);
script[LOCAL] = NULL;
continue;
}
if (script[REMOTE]
&& scripteq(oscript, script[REMOTE])) {
/* BOLT #5:
*
* - MUST *resolve* the _remote node's main output_ by
* spending it using the revocation private key.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid, tx_blockheight,
THEIR_REVOKED_UNILATERAL, i,
amt,
DELAYED_OUTPUT_TO_THEM,
NULL, NULL, NULL);
steal_to_them_output(out);
script[REMOTE] = NULL;
continue;
}
matches = match_htlc_output(tmpctx, tx, i, htlc_scripts);
if (tal_count(matches) == 0)
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not find resolution for output %zu",
i);
/* In this case, we don't care which HTLC we choose; so pick
first one */
which_htlc = matches[0];
if (matches_direction(matches, htlcs) == LOCAL) {
/* BOLT #5:
*
* - MUST *resolve* the _local node's offered HTLCs_ in one of three ways:
* * spend the *commitment tx* using the payment revocation private key.
* * spend the *commitment tx* once the HTLC timeout has passed.
* * spend the *HTLC-success tx*, if the remote node has published it.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid,
tx_blockheight,
THEIR_REVOKED_UNILATERAL, i,
amt,
OUR_HTLC,
&htlcs[which_htlc],
htlc_scripts[which_htlc],
NULL);
steal_htlc(out);
} else {
out = new_tracked_output(tx->chainparams,
&outs, txid,
tx_blockheight,
THEIR_REVOKED_UNILATERAL, i,
amt,
THEIR_HTLC,
&htlcs[which_htlc],
htlc_scripts[which_htlc],
NULL);
/* BOLT #5:
*
* - MUST *resolve* the _remote node's offered HTLCs_ in one of three ways:
* * spend the *commitment tx* using the payment revocation private key.
* * spend the *commitment tx* using the payment preimage (if known).
* * spend the *HTLC-timeout tx*, if the remote node has published it.
*/
steal_htlc(out);
}
htlc_scripts[which_htlc] = NULL;
}
note_missing_htlcs(htlc_scripts, htlcs,
tell_if_missing, tell_immediately);
wait_for_resolved(tx->chainparams, outs);
}
static void handle_their_unilateral(const struct bitcoin_tx *tx,
u32 tx_blockheight,
const struct bitcoin_txid *txid,
const struct pubkey *this_remote_per_commitment_point,
const struct basepoints basepoints[NUM_SIDES],
const struct htlc_stub *htlcs,
const bool *tell_if_missing,
const bool *tell_immediately,
struct tracked_output **outs)
{
u8 **htlc_scripts;
u8 *remote_wscript, *script[NUM_SIDES];
struct keyset *ks;
size_t i;
init_reply("Tracking their unilateral close");
onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL | TX_THEIRS);
/* HSM can't derive this. */
remote_per_commitment_point = this_remote_per_commitment_point;
/* BOLT #5:
*
* # Unilateral Close Handling: Remote Commitment Transaction
*
* The *remote node's* commitment transaction *resolves* the funding
* transaction output.
*
* There are no delays constraining node behavior in this case, so
* it's simpler for a node to handle than the case in which it
* discovers its local commitment transaction (see [Unilateral Close
* Handling: Local Commitment Transaction]
*/
resolved_by_other(outs[0], txid, THEIR_UNILATERAL);
status_debug("Deriving keyset %"PRIu64
": per_commit_point=%s"
" self_payment_basepoint=%s"
" other_payment_basepoint=%s"
" self_htlc_basepoint=%s"
" other_htlc_basepoint=%s"
" self_delayed_basepoint=%s"
" other_revocation_basepoint=%s",
commit_num,
type_to_string(tmpctx, struct pubkey,
remote_per_commitment_point),
type_to_string(tmpctx, struct pubkey,
&basepoints[REMOTE].payment),
type_to_string(tmpctx, struct pubkey,
&basepoints[LOCAL].payment),
type_to_string(tmpctx, struct pubkey,
&basepoints[REMOTE].htlc),
type_to_string(tmpctx, struct pubkey,
&basepoints[LOCAL].htlc),
type_to_string(tmpctx, struct pubkey,
&basepoints[REMOTE].delayed_payment),
type_to_string(tmpctx, struct pubkey,
&basepoints[LOCAL].revocation));
/* keyset is const, we need a non-const ptr to set it up */
keyset = ks = tal(tx, struct keyset);
if (!derive_keyset(remote_per_commitment_point,
&basepoints[REMOTE],
&basepoints[LOCAL],
option_static_remotekey,
ks))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Deriving keyset for %"PRIu64, commit_num);
status_debug("Deconstructing unilateral tx: %"PRIu64
" using keyset: "
" self_revocation_key: %s"
" self_delayed_payment_key: %s"
" self_payment_key: %s"
" other_payment_key: %s"
" self_htlc_key: %s"
" other_htlc_key: %s",
commit_num,
type_to_string(tmpctx, struct pubkey,
&keyset->self_revocation_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_delayed_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->other_payment_key),
type_to_string(tmpctx, struct pubkey,
&keyset->self_htlc_key),
type_to_string(tmpctx, struct pubkey,
&keyset->other_htlc_key));
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);
/* Figure out what direct to-us output looks like. */
script[LOCAL] = scriptpubkey_p2wpkh(tmpctx, &keyset->other_payment_key);
/* Calculate all the HTLC scripts so we can match them */
htlc_scripts = derive_htlc_scripts(htlcs, REMOTE);
status_debug("Script to-them: %u: %s (%s)",
to_self_delay[REMOTE],
tal_hex(tmpctx, script[REMOTE]),
tal_hex(tmpctx, remote_wscript));
status_debug("Script to-me: %s",
tal_hex(tmpctx, script[LOCAL]));
for (i = 0; i < tx->wtx->num_outputs; i++) {
status_debug("Output %zu: %s", i,
tal_hex(tmpctx, bitcoin_tx_output_get_script(
tmpctx, tx, i)));
}
for (i = 0; i < tx->wtx->num_outputs; i++) {
struct tracked_output *out;
const size_t *matches;
size_t which_htlc;
const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i);
struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i);
if (script[LOCAL] && scripteq(oscript, script[LOCAL])) {
/* BOLT #5:
*
* - MAY take no action in regard to the associated
* `to_remote`, which is simply a P2WPKH output to
* the *local node*.
* - Note: `to_remote` is considered *resolved* by the
* commitment transaction itself.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid, tx_blockheight,
THEIR_UNILATERAL,
i, amt,
OUTPUT_TO_US, NULL, NULL, NULL);
ignore_output(out);
tell_wallet_to_remote(tx, i, txid,
tx_blockheight,
script[LOCAL],
remote_per_commitment_point,
option_static_remotekey);
script[LOCAL] = NULL;
continue;
}
if (script[REMOTE]
&& scripteq(oscript, script[REMOTE])) {
/* BOLT #5:
*
* - MAY take no action in regard to the associated
* `to_local`, which is a payment output to the *remote
* node*.
* - Note: `to_local` is considered *resolved* by the
* commitment transaction itself.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid, tx_blockheight,
THEIR_UNILATERAL, i,
amt,
DELAYED_OUTPUT_TO_THEM,
NULL, NULL, NULL);
ignore_output(out);
continue;
}
matches = match_htlc_output(tmpctx, tx, i, htlc_scripts);
if (tal_count(matches) == 0)
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Could not find resolution for output %zu",
i);
if (matches_direction(matches, htlcs) == LOCAL) {
/* BOLT #5:
*
* - MUST handle HTLCs offered by itself as specified in
* [HTLC Output Handling: Remote Commitment,
* Local Offers]
*/
out = new_tracked_output(tx->chainparams,
&outs, txid,
tx_blockheight,
THEIR_UNILATERAL, i,
amt,
OUR_HTLC,
NULL, NULL,
NULL);
which_htlc = resolve_our_htlc_theircommit(out,
matches,
htlcs,
htlc_scripts);
} else {
out = new_tracked_output(tx->chainparams,
&outs, txid,
tx_blockheight,
THEIR_UNILATERAL, i,
amt,
THEIR_HTLC,
NULL, NULL,
NULL);
/* BOLT #5:
*
* - MUST handle HTLCs offered by the remote node as
* specified in [HTLC Output Handling: Remote
* Commitment, Remote Offers]
*/
which_htlc = resolve_their_htlc(out, matches, htlcs,
htlc_scripts);
}
out->htlc = htlcs[which_htlc];
out->wscript = tal_steal(out, htlc_scripts[which_htlc]);
htlc_scripts[which_htlc] = NULL;
}
note_missing_htlcs(htlc_scripts, htlcs,
tell_if_missing, tell_immediately);
wait_for_resolved(tx->chainparams, outs);
}
static void handle_unknown_commitment(const struct bitcoin_tx *tx,
u32 tx_blockheight,
u64 commit_num,
const struct bitcoin_txid *txid,
const struct pubkey *possible_remote_per_commitment_point,
const struct basepoints basepoints[NUM_SIDES],
const struct htlc_stub *htlcs,
const bool *tell_if_missing,
struct tracked_output **outs)
{
int to_us_output = -1;
u8 *local_script;
onchain_transaction_annotate(txid, TX_CHANNEL_UNILATERAL | TX_THEIRS);
resolved_by_other(outs[0], txid, UNKNOWN_UNILATERAL);
/* If they don't give us a per-commitment point and we rotate keys,
* we're out of luck. */
if (!possible_remote_per_commitment_point
&& !option_static_remotekey)
goto search_done;
if (!option_static_remotekey) {
struct keyset *ks = tal(tmpctx, struct keyset);
if (!derive_keyset(possible_remote_per_commitment_point,
&basepoints[REMOTE],
&basepoints[LOCAL],
option_static_remotekey,
ks))
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Deriving keyset for possible_remote_per_commitment_point %s",
type_to_string(tmpctx, struct pubkey,
possible_remote_per_commitment_point));
local_script = scriptpubkey_p2wpkh(tmpctx,
&ks->other_payment_key);
} else {
/* BOLT #3:
*
* ### `remotepubkey` Derivation
*
* If `option_static_remotekey` is negotiated the
* `remotepubkey` is simply the remote node's
* `payment_basepoint`, otherwise it is calculated as above
* using the remote node's `payment_basepoint`.
*/
local_script = scriptpubkey_p2wpkh(tmpctx,
&basepoints[LOCAL].payment);
}
for (size_t i = 0; i < tx->wtx->num_outputs; i++) {
struct tracked_output *out;
const u8 *oscript = bitcoin_tx_output_get_script(tmpctx, tx, i);
struct amount_sat amt = bitcoin_tx_output_get_amount(tx, i);
if (local_script
&& scripteq(oscript, local_script)) {
/* BOLT #5:
*
* - MAY take no action in regard to the associated
* `to_remote`, which is simply a P2WPKH output to
* the *local node*.
* - Note: `to_remote` is considered *resolved* by the
* commitment transaction itself.
*/
out = new_tracked_output(tx->chainparams,
&outs, txid, tx_blockheight,
UNKNOWN_UNILATERAL,
i, amt,
OUTPUT_TO_US, NULL, NULL, NULL);
ignore_output(out);
tell_wallet_to_remote(tx, i, txid,
tx_blockheight,
local_script,
possible_remote_per_commitment_point,
option_static_remotekey);
local_script = NULL;
to_us_output = i;
}
}
search_done:
if (to_us_output == -1) {
status_broken("FUNDS LOST. Unknown commitment #%"PRIu64"!",
commit_num);
init_reply("ERROR: FUNDS LOST. Unknown commitment!");
} else {
status_broken("ERROR: Unknown commitment #%"PRIu64
", recovering our funds!",
commit_num);
init_reply("ERROR: Unknown commitment, recovering our funds!");
}
/* Tell master to give up on HTLCs immediately. */
for (size_t i = 0; i < tal_count(htlcs); i++) {
u8 *msg;
if (!tell_if_missing[i])
continue;
msg = towire_onchain_missing_htlc_output(NULL, &htlcs[i]);
wire_sync_write(REQ_FD, take(msg));
}
wait_for_resolved(tx->chainparams, outs);
}
int main(int argc, char *argv[])
{
setup_locale();
const tal_t *ctx = tal(NULL, char);
u8 *msg;
struct pubkey remote_per_commit_point, old_remote_per_commit_point;
enum side funder;
struct basepoints basepoints[NUM_SIDES];
struct shachain shachain;
struct bitcoin_tx *tx;
struct tracked_output **outs;
struct bitcoin_txid our_broadcast_txid, txid, tmptxid;
secp256k1_ecdsa_signature *remote_htlc_sigs;
struct amount_sat funding;
u64 num_htlcs;
u8 *scriptpubkey[NUM_SIDES];
struct htlc_stub *htlcs;
bool *tell_if_missing, *tell_immediately;
u32 tx_blockheight;
struct pubkey *possible_remote_per_commitment_point;
struct bitcoin_blkid chain_hash;
subdaemon_setup(argc, argv);
status_setup_sync(REQ_FD);
missing_htlc_msgs = tal_arr(ctx, u8 *, 0);
msg = wire_sync_read(tmpctx, REQ_FD);
if (!fromwire_onchain_init(tmpctx, msg,
&shachain,
&chain_hash,
&funding,
&old_remote_per_commit_point,
&remote_per_commit_point,
&to_self_delay[LOCAL],
&to_self_delay[REMOTE],
&feerate_per_kw,
&dust_limit,
&our_broadcast_txid,
&scriptpubkey[LOCAL],
&scriptpubkey[REMOTE],
&our_wallet_pubkey,
&funder,
&basepoints[LOCAL],
&basepoints[REMOTE],
&tx,
&tx_blockheight,
&reasonable_depth,
&remote_htlc_sigs,
&num_htlcs,
&min_possible_feerate,
&max_possible_feerate,
&possible_remote_per_commitment_point,
&option_static_remotekey)) {
master_badmsg(WIRE_ONCHAIN_INIT, msg);
}
tx->chainparams = chainparams_by_chainhash(&chain_hash);
status_debug("feerate_per_kw = %u", feerate_per_kw);
bitcoin_txid(tx, &txid);
/* We need to keep tx around, but there's only one: not really a leak */
tal_steal(ctx, notleak(tx));
/* FIXME: Filter as we go, don't load them all into mem! */
htlcs = tal_arr(tmpctx, struct htlc_stub, num_htlcs);
tell_if_missing = tal_arr(htlcs, bool, num_htlcs);
tell_immediately = tal_arr(htlcs, bool, num_htlcs);
if (!htlcs || !tell_if_missing || !tell_immediately)
status_failed(STATUS_FAIL_INTERNAL_ERROR,
"Can't allocate %"PRIu64" htlcs", num_htlcs);
for (u64 i = 0; i < num_htlcs; i++) {
msg = wire_sync_read(tmpctx, REQ_FD);
if (!fromwire_onchain_htlc(msg, &htlcs[i],
&tell_if_missing[i],
&tell_immediately[i]))
master_badmsg(WIRE_ONCHAIN_HTLC, msg);
}
outs = tal_arr(ctx, struct tracked_output *, 0);
bitcoin_tx_input_get_txid(tx, 0, &tmptxid);
new_tracked_output(tx->chainparams, &outs, &tmptxid,
0, /* We don't care about funding blockheight */
FUNDING_TRANSACTION,
tx->wtx->inputs[0].index,
funding,
FUNDING_OUTPUT, NULL, NULL, NULL);
status_debug("Remote per-commit point: %s",
type_to_string(tmpctx, struct pubkey,
&remote_per_commit_point));
status_debug("Old remote per-commit point: %s",
type_to_string(tmpctx, struct pubkey,
&old_remote_per_commit_point));
/* BOLT #5:
*
* There are three ways a channel can end:
*
* 1. The good way (*mutual close*): at some point the local and
* remote nodes agree to close the channel. They generate a *closing
* transaction* (which is similar to a commitment transaction, but
* without any pending payments) and publish it on the blockchain (see
* [BOLT #2: Channel Close](02-peer-protocol.md#channel-close)).
*/
if (is_mutual_close(tx, scriptpubkey[LOCAL], scriptpubkey[REMOTE]))
handle_mutual_close(tx->chainparams, &txid, outs);
else {
/* BOLT #5:
*
* 2. The bad way (*unilateral close*): something goes wrong,
* possibly without evil intent on either side. Perhaps one
* party crashed, for instance. One side publishes its
* *latest commitment transaction*.
*/
struct secret revocation_preimage;
commit_num = unmask_commit_number(tx, funder,
&basepoints[LOCAL].payment,
&basepoints[REMOTE].payment);
status_debug("commitnum = %"PRIu64
", revocations_received = %"PRIu64,
commit_num, revocations_received(&shachain));
if (is_local_commitment(&txid, &our_broadcast_txid))
handle_our_unilateral(tx, tx_blockheight, &txid,
basepoints,
htlcs,
tell_if_missing, tell_immediately,
remote_htlc_sigs,
outs);
/* BOLT #5:
*
* 3. The ugly way (*revoked transaction close*): one of the
* parties deliberately tries to cheat, by publishing an
* *outdated commitment transaction* (presumably, a prior
* version, which is more in its favor).
*/
else if (shachain_get_secret(&shachain, commit_num,
&revocation_preimage)) {
handle_their_cheat(tx, &txid,
tx_blockheight,
&revocation_preimage,
basepoints,
htlcs,
tell_if_missing, tell_immediately,
outs);
/* BOLT #5:
*
* There may be more than one valid, *unrevoked* commitment
* transaction after a signature has been received via
* `commitment_signed` and before the corresponding
* `revoke_and_ack`. As such, either commitment may serve as
* the *remote node's* commitment transaction; hence, the
* local node is required to handle both.
*/
} else if (commit_num == revocations_received(&shachain)) {
status_debug("Their unilateral tx, old commit point");
handle_their_unilateral(tx, tx_blockheight,
&txid,
&old_remote_per_commit_point,
basepoints,
htlcs,
tell_if_missing,
tell_immediately,
outs);
} else if (commit_num == revocations_received(&shachain) + 1) {
status_debug("Their unilateral tx, new commit point");
handle_their_unilateral(tx, tx_blockheight,
&txid,
&remote_per_commit_point,
basepoints,
htlcs,
tell_if_missing,
tell_immediately,
outs);
} else {
handle_unknown_commitment(tx, tx_blockheight,
commit_num,
&txid,
possible_remote_per_commitment_point,
basepoints,
htlcs,
tell_if_missing,
outs);
}
}
/* We're done! */
tal_free(ctx);
daemon_shutdown();
return 0;
}