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#include <closingd/gen_closing_wire.h>
#include <common/close_tx.h>
#include <common/initial_commit_tx.h>
#include <common/utils.h>
#include <errno.h>
#include <inttypes.h>
#include <lightningd/chaintopology.h>
#include <lightningd/channel.h>
#include <lightningd/closing_control.h>
#include <lightningd/lightningd.h>
#include <lightningd/log.h>
#include <lightningd/options.h>
#include <lightningd/peer_control.h>
#include <lightningd/subd.h>
/* Is this better than the last tx we were holding? This can happen
* even without closingd misbehaving, if we have multiple,
* interrupted, rounds of negotiation. */
static bool better_closing_fee(struct lightningd *ld,
struct channel *channel,
const struct bitcoin_tx *tx)
{
u64 weight, fee, last_fee, ideal_fee, min_fee;
s64 old_diff, new_diff;
size_t i;
/* Calculate actual fee (adds in eliminated outputs) */
fee = channel->funding_satoshi;
for (i = 0; i < tal_count(tx->output); i++)
fee -= tx->output[i].amount;
last_fee = channel->funding_satoshi;
for (i = 0; i < tal_count(channel->last_tx); i++)
last_fee -= channel->last_tx->output[i].amount;
log_debug(channel->log, "Their actual closing tx fee is %"PRIu64
" vs previous %"PRIu64, fee, last_fee);
/* Weight once we add in sigs. */
weight = measure_tx_weight(tx) + 74 * 2;
min_fee = get_feerate(ld->topology, FEERATE_SLOW) * weight / 1000;
if (fee < min_fee) {
log_debug(channel->log, "... That's below our min %"PRIu64
" for weight %"PRIu64" at feerate %u",
min_fee, weight,
get_feerate(ld->topology, FEERATE_SLOW));
return false;
}
ideal_fee = get_feerate(ld->topology, FEERATE_NORMAL) * weight / 1000;
/* We prefer fee which is closest to our ideal. */
old_diff = imaxabs((s64)ideal_fee - (s64)last_fee);
new_diff = imaxabs((s64)ideal_fee - (s64)fee);
/* In case of a tie, prefer new over old: this covers the preference
* for a mutual close over a unilateral one. */
log_debug(channel->log, "... That's %s our ideal %"PRIu64,
new_diff < old_diff
? "closer to"
: new_diff > old_diff
? "further from"
: "same distance to",
ideal_fee);
return new_diff <= old_diff;
}
static void peer_received_closing_signature(struct channel *channel,
const u8 *msg)
{
secp256k1_ecdsa_signature sig;
struct bitcoin_tx *tx;
struct lightningd *ld = channel->peer->ld;
if (!fromwire_closing_received_signature(msg, msg, &sig, &tx)) {
channel_internal_error(channel, "Bad closing_received_signature %s",
tal_hex(msg, msg));
return;
}
/* FIXME: Make sure signature is correct! */
if (better_closing_fee(ld, channel, tx)) {
channel_set_last_tx(channel, tx, &sig);
/* TODO(cdecker) Selectively save updated fields to DB */
wallet_channel_save(ld->wallet, channel);
}
/* OK, you can continue now. */
subd_send_msg(channel->owner,
take(towire_closing_received_signature_reply(channel)));
}
static void peer_closing_complete(struct channel *channel, const u8 *msg)
{
/* FIXME: We should save this, to return to gossipd */
u64 gossip_index;
if (!fromwire_closing_complete(msg, &gossip_index)) {
channel_internal_error(channel, "Bad closing_complete %s",
tal_hex(msg, msg));
return;
}
/* Retransmission only, ignore closing. */
if (channel->state == CLOSINGD_COMPLETE)
return;
drop_to_chain(channel->peer->ld, channel);
channel_set_state(channel, CLOSINGD_SIGEXCHANGE, CLOSINGD_COMPLETE);
}
static unsigned closing_msg(struct subd *sd, const u8 *msg, const int *fds)
{
enum closing_wire_type t = fromwire_peektype(msg);
switch (t) {
case WIRE_CLOSING_RECEIVED_SIGNATURE:
peer_received_closing_signature(sd->channel, msg);
break;
case WIRE_CLOSING_COMPLETE:
peer_closing_complete(sd->channel, msg);
break;
/* We send these, not receive them */
case WIRE_CLOSING_INIT:
case WIRE_CLOSING_RECEIVED_SIGNATURE_REPLY:
break;
}
return 0;
}
void peer_start_closingd(struct channel *channel,
struct crypto_state *cs,
u64 gossip_index,
int peer_fd, int gossip_fd,
bool reconnected)
{
const tal_t *tmpctx = tal_tmpctx(channel);
u8 *initmsg, *local_scriptpubkey;
u64 minfee, startfee, feelimit;
u64 num_revocations;
u64 funding_msatoshi, our_msatoshi, their_msatoshi;
struct lightningd *ld = channel->peer->ld;
if (channel->local_shutdown_idx == -1
|| !channel->remote_shutdown_scriptpubkey) {
channel_internal_error(channel,
"Can't start closing: local %s remote %s",
channel->local_shutdown_idx == -1
? "not shutdown" : "shutdown",
channel->remote_shutdown_scriptpubkey
? "shutdown" : "not shutdown");
tal_free(tmpctx);
return;
}
channel_set_owner(channel, new_channel_subd(ld,
"lightning_closingd",
channel, channel->log,
closing_wire_type_name, closing_msg,
channel_errmsg,
channel_set_billboard,
take(&peer_fd), take(&gossip_fd),
NULL));
if (!channel->owner) {
log_unusual(channel->log, "Could not subdaemon closing: %s",
strerror(errno));
channel_fail_transient(channel, "Failed to subdaemon closing");
tal_free(tmpctx);
return;
}
local_scriptpubkey = p2wpkh_for_keyidx(tmpctx, ld,
channel->local_shutdown_idx);
if (!local_scriptpubkey) {
channel_internal_error(channel,
"Can't generate local shutdown scriptpubkey");
tal_free(tmpctx);
return;
}
/* BOLT #2:
*
* A sending node MUST set `fee_satoshis` lower than or equal
* to the base fee of the final commitment transaction as
* calculated in [BOLT
* #3](03-transactions.md#fee-calculation).
*/
feelimit = commit_tx_base_fee(channel->channel_info.feerate_per_kw[LOCAL],
0);
minfee = commit_tx_base_fee(get_feerate(ld->topology, FEERATE_SLOW), 0);
startfee = commit_tx_base_fee(get_feerate(ld->topology, FEERATE_NORMAL),
0);
if (startfee > feelimit)
startfee = feelimit;
if (minfee > feelimit)
minfee = feelimit;
num_revocations
= revocations_received(&channel->their_shachain.chain);
/* BOLT #3:
*
* The amounts for each output MUST BE rounded down to whole satoshis.
*/
/* Convert unit */
funding_msatoshi = channel->funding_satoshi * 1000;
/* What is not ours is theirs */
our_msatoshi = channel->our_msatoshi;
their_msatoshi = funding_msatoshi - our_msatoshi;
initmsg = towire_closing_init(tmpctx,
cs,
gossip_index,
&channel->seed,
&channel->funding_txid,
channel->funding_outnum,
channel->funding_satoshi,
&channel->channel_info.remote_fundingkey,
channel->funder,
our_msatoshi / 1000, /* Rounds down */
their_msatoshi / 1000, /* Rounds down */
channel->our_config.dust_limit_satoshis,
minfee, feelimit, startfee,
local_scriptpubkey,
channel->remote_shutdown_scriptpubkey,
reconnected,
channel->next_index[LOCAL],
channel->next_index[REMOTE],
num_revocations,
deprecated_apis);
/* We don't expect a response: it will give us feedback on
* signatures sent and received, then closing_complete. */
subd_send_msg(channel->owner, take(initmsg));
tal_free(tmpctx);
}