Rusty Russell
7 years ago
committed by
Christian Decker
Christian Decker
6 changed files with 283 additions and 257 deletions
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#include <closingd/gen_closing_wire.h> |
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#include <common/close_tx.h> |
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#include <common/initial_commit_tx.h> |
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#include <common/utils.h> |
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#include <errno.h> |
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#include <inttypes.h> |
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#include <lightningd/chaintopology.h> |
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#include <lightningd/channel.h> |
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#include <lightningd/closing_control.h> |
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#include <lightningd/lightningd.h> |
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#include <lightningd/log.h> |
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#include <lightningd/options.h> |
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#include <lightningd/peer_control.h> |
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#include <lightningd/subd.h> |
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/* Is this better than the last tx we were holding? This can happen
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* even without closingd misbehaving, if we have multiple, |
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* interrupted, rounds of negotiation. */ |
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static bool better_closing_fee(struct lightningd *ld, |
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struct channel *channel, |
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const struct bitcoin_tx *tx) |
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{ |
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u64 weight, fee, last_fee, ideal_fee, min_fee; |
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s64 old_diff, new_diff; |
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size_t i; |
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/* Calculate actual fee (adds in eliminated outputs) */ |
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fee = channel->funding_satoshi; |
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for (i = 0; i < tal_count(tx->output); i++) |
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fee -= tx->output[i].amount; |
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last_fee = channel->funding_satoshi; |
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for (i = 0; i < tal_count(channel->last_tx); i++) |
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last_fee -= channel->last_tx->output[i].amount; |
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log_debug(channel->log, "Their actual closing tx fee is %"PRIu64 |
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" vs previous %"PRIu64, fee, last_fee); |
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/* Weight once we add in sigs. */ |
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weight = measure_tx_weight(tx) + 74 * 2; |
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min_fee = get_feerate(ld->topology, FEERATE_SLOW) * weight / 1000; |
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if (fee < min_fee) { |
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log_debug(channel->log, "... That's below our min %"PRIu64 |
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" for weight %"PRIu64" at feerate %u", |
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min_fee, weight, |
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get_feerate(ld->topology, FEERATE_SLOW)); |
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return false; |
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} |
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ideal_fee = get_feerate(ld->topology, FEERATE_NORMAL) * weight / 1000; |
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/* We prefer fee which is closest to our ideal. */ |
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old_diff = imaxabs((s64)ideal_fee - (s64)last_fee); |
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new_diff = imaxabs((s64)ideal_fee - (s64)fee); |
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/* In case of a tie, prefer new over old: this covers the preference
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* for a mutual close over a unilateral one. */ |
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log_debug(channel->log, "... That's %s our ideal %"PRIu64, |
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new_diff < old_diff |
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? "closer to" |
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: new_diff > old_diff |
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? "further from" |
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: "same distance to", |
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ideal_fee); |
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return new_diff <= old_diff; |
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} |
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static void peer_received_closing_signature(struct channel *channel, |
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const u8 *msg) |
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{ |
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secp256k1_ecdsa_signature sig; |
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struct bitcoin_tx *tx; |
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struct lightningd *ld = channel->peer->ld; |
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if (!fromwire_closing_received_signature(msg, msg, NULL, &sig, &tx)) { |
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channel_internal_error(channel, "Bad closing_received_signature %s", |
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tal_hex(msg, msg)); |
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return; |
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} |
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/* FIXME: Make sure signature is correct! */ |
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if (better_closing_fee(ld, channel, tx)) { |
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channel_set_last_tx(channel, tx, &sig); |
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/* TODO(cdecker) Selectively save updated fields to DB */ |
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wallet_channel_save(ld->wallet, channel); |
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} |
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/* OK, you can continue now. */ |
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subd_send_msg(channel->owner, |
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take(towire_closing_received_signature_reply(channel))); |
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} |
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static void peer_closing_complete(struct channel *channel, const u8 *msg) |
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{ |
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/* FIXME: We should save this, to return to gossipd */ |
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u64 gossip_index; |
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if (!fromwire_closing_complete(msg, NULL, &gossip_index)) { |
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channel_internal_error(channel, "Bad closing_complete %s", |
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tal_hex(msg, msg)); |
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return; |
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} |
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/* Retransmission only, ignore closing. */ |
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if (channel->state == CLOSINGD_COMPLETE) |
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return; |
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drop_to_chain(channel->peer->ld, channel); |
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channel_set_state(channel, CLOSINGD_SIGEXCHANGE, CLOSINGD_COMPLETE); |
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} |
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static unsigned closing_msg(struct subd *sd, const u8 *msg, const int *fds) |
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{ |
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enum closing_wire_type t = fromwire_peektype(msg); |
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switch (t) { |
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case WIRE_CLOSING_RECEIVED_SIGNATURE: |
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peer_received_closing_signature(sd->channel, msg); |
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break; |
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case WIRE_CLOSING_COMPLETE: |
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peer_closing_complete(sd->channel, msg); |
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break; |
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/* We send these, not receive them */ |
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case WIRE_CLOSING_INIT: |
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case WIRE_CLOSING_RECEIVED_SIGNATURE_REPLY: |
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break; |
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} |
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return 0; |
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} |
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void peer_start_closingd(struct channel *channel, |
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struct crypto_state *cs, |
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u64 gossip_index, |
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int peer_fd, int gossip_fd, |
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bool reconnected) |
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{ |
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const tal_t *tmpctx = tal_tmpctx(channel); |
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u8 *initmsg, *local_scriptpubkey; |
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u64 minfee, startfee, feelimit; |
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u64 num_revocations; |
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u64 funding_msatoshi, our_msatoshi, their_msatoshi; |
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struct lightningd *ld = channel->peer->ld; |
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if (channel->local_shutdown_idx == -1 |
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|| !channel->remote_shutdown_scriptpubkey) { |
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channel_internal_error(channel, |
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"Can't start closing: local %s remote %s", |
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channel->local_shutdown_idx == -1 |
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? "not shutdown" : "shutdown", |
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channel->remote_shutdown_scriptpubkey |
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? "shutdown" : "not shutdown"); |
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tal_free(tmpctx); |
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return; |
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} |
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channel_set_owner(channel, new_channel_subd(ld, |
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"lightning_closingd", |
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channel, channel->log, |
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closing_wire_type_name, closing_msg, |
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channel_errmsg, |
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take(&peer_fd), take(&gossip_fd), |
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NULL)); |
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if (!channel->owner) { |
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log_unusual(channel->log, "Could not subdaemon closing: %s", |
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strerror(errno)); |
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channel_fail_transient(channel, "Failed to subdaemon closing"); |
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tal_free(tmpctx); |
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return; |
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} |
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local_scriptpubkey = p2wpkh_for_keyidx(tmpctx, ld, |
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channel->local_shutdown_idx); |
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if (!local_scriptpubkey) { |
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channel_internal_error(channel, |
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"Can't generate local shutdown scriptpubkey"); |
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tal_free(tmpctx); |
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return; |
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} |
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/* BOLT #2:
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* |
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* A sending node MUST set `fee_satoshis` lower than or equal |
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* to the base fee of the final commitment transaction as |
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* calculated in [BOLT |
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* #3](03-transactions.md#fee-calculation). |
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*/ |
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feelimit = commit_tx_base_fee(channel->channel_info.feerate_per_kw[LOCAL], |
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0); |
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minfee = commit_tx_base_fee(get_feerate(ld->topology, FEERATE_SLOW), 0); |
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startfee = commit_tx_base_fee(get_feerate(ld->topology, FEERATE_NORMAL), |
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0); |
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if (startfee > feelimit) |
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startfee = feelimit; |
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if (minfee > feelimit) |
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minfee = feelimit; |
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num_revocations |
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= revocations_received(&channel->their_shachain.chain); |
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/* BOLT #3:
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* |
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* The amounts for each output MUST BE rounded down to whole satoshis. |
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*/ |
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/* Convert unit */ |
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funding_msatoshi = channel->funding_satoshi * 1000; |
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/* What is not ours is theirs */ |
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our_msatoshi = channel->our_msatoshi; |
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their_msatoshi = funding_msatoshi - our_msatoshi; |
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initmsg = towire_closing_init(tmpctx, |
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cs, |
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gossip_index, |
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&channel->seed, |
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&channel->funding_txid, |
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channel->funding_outnum, |
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channel->funding_satoshi, |
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&channel->channel_info.remote_fundingkey, |
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channel->funder, |
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our_msatoshi / 1000, /* Rounds down */ |
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their_msatoshi / 1000, /* Rounds down */ |
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channel->our_config.dust_limit_satoshis, |
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minfee, feelimit, startfee, |
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local_scriptpubkey, |
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channel->remote_shutdown_scriptpubkey, |
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reconnected, |
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channel->next_index[LOCAL], |
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channel->next_index[REMOTE], |
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num_revocations, |
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deprecated_apis); |
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/* We don't expect a response: it will give us feedback on
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* signatures sent and received, then closing_complete. */ |
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subd_send_msg(channel->owner, take(initmsg)); |
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tal_free(tmpctx); |
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} |
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@ -0,0 +1,15 @@ |
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#ifndef LIGHTNING_LIGHTNINGD_CLOSING_CONTROL_H |
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#define LIGHTNING_LIGHTNINGD_CLOSING_CONTROL_H |
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#include "config.h" |
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#include <ccan/short_types/short_types.h> |
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struct channel_id; |
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struct crypto_state; |
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void peer_start_closingd(struct channel *channel, |
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struct crypto_state *cs, |
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u64 gossip_index, |
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int peer_fd, int gossip_fd, |
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bool reconnected); |
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#endif /* LIGHTNING_LIGHTNINGD_CLOSING_CONTROL_H */ |
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