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578 lines
17 KiB
578 lines
17 KiB
#include <bitcoin/script.h>
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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/crypto_sync.h>
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#include <common/derive_basepoints.h>
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#include <common/htlc.h>
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#include <common/peer_billboard.h>
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#include <common/peer_failed.h>
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#include <common/read_peer_msg.h>
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#include <common/socket_close.h>
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#include <common/status.h>
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#include <common/subdaemon.h>
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#include <common/type_to_string.h>
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#include <common/utils.h>
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#include <common/version.h>
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#include <common/wire_error.h>
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#include <errno.h>
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#include <hsmd/gen_hsm_wire.h>
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#include <inttypes.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <wire/peer_wire.h>
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#include <wire/wire_sync.h>
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/* stdin == requests, 3 == peer, 4 = gossip */
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#define REQ_FD STDIN_FILENO
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#define PEER_FD 3
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#define GOSSIP_FD 4
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#define HSM_FD 5
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static struct bitcoin_tx *close_tx(const tal_t *ctx,
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struct crypto_state *cs,
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const struct channel_id *channel_id,
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u8 *scriptpubkey[NUM_SIDES],
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const struct bitcoin_txid *funding_txid,
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unsigned int funding_txout,
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u64 funding_satoshi,
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const u64 satoshi_out[NUM_SIDES],
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enum side funder,
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uint64_t fee,
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uint64_t dust_limit)
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{
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struct bitcoin_tx *tx;
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if (satoshi_out[funder] < fee)
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peer_failed(cs, channel_id,
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"Funder cannot afford fee %"PRIu64
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" (%"PRIu64" and %"PRIu64")",
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fee, satoshi_out[LOCAL],
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satoshi_out[REMOTE]);
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status_trace("Making close tx at = %"PRIu64"/%"PRIu64" fee %"PRIu64,
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satoshi_out[LOCAL], satoshi_out[REMOTE], fee);
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/* FIXME: We need to allow this! */
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tx = create_close_tx(ctx,
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scriptpubkey[LOCAL], scriptpubkey[REMOTE],
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funding_txid,
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funding_txout,
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funding_satoshi,
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satoshi_out[LOCAL] - (funder == LOCAL ? fee : 0),
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satoshi_out[REMOTE] - (funder == REMOTE ? fee : 0),
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dust_limit);
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if (!tx)
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peer_failed(cs, channel_id,
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"Both outputs below dust limit:"
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" funding = %"PRIu64
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" fee = %"PRIu64
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" dust_limit = %"PRIu64
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" LOCAL = %"PRIu64
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" REMOTE = %"PRIu64,
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funding_satoshi,
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fee,
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dust_limit,
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satoshi_out[LOCAL],
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satoshi_out[REMOTE]);
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return tx;
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}
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/* Handle random messages we might get, returning the first non-handled one. */
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static u8 *closing_read_peer_msg(const tal_t *ctx,
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struct crypto_state *cs,
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const struct channel_id *channel_id)
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{
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for (;;) {
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u8 *msg;
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bool from_gossipd;
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clean_tmpctx();
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msg = peer_or_gossip_sync_read(ctx, PEER_FD, GOSSIP_FD,
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cs, &from_gossipd);
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if (from_gossipd) {
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handle_gossip_msg(PEER_FD, cs, take(msg));
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continue;
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}
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if (!handle_peer_gossip_or_error(PEER_FD, GOSSIP_FD, cs,
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channel_id, msg))
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return msg;
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}
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}
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static void do_reconnect(struct crypto_state *cs,
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const struct channel_id *channel_id,
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const u64 next_index[NUM_SIDES],
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u64 revocations_received,
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const u8 *channel_reestablish)
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{
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u8 *msg;
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struct channel_id their_channel_id;
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u64 next_local_commitment_number, next_remote_revocation_number;
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/* BOLT #2:
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*
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* - upon reconnection:
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* - if a channel is in an error state:
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* - SHOULD retransmit the error packet and ignore any other packets for
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* that channel.
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* - otherwise:
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* - MUST transmit `channel_reestablish` for each channel.
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* - MUST wait to receive the other node's `channel_reestablish`
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* message before sending any other messages for that channel.
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*
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* The sending node:
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* - MUST set `next_local_commitment_number` to the commitment number
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* of the next `commitment_signed` it expects to receive.
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* - MUST set `next_remote_revocation_number` to the commitment number
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* of the next `revoke_and_ack` message it expects to receive.
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*/
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msg = towire_channel_reestablish(NULL, channel_id,
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next_index[LOCAL],
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revocations_received);
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sync_crypto_write(cs, PEER_FD, take(msg));
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/* They might have already send reestablish, which triggered us */
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if (!channel_reestablish)
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channel_reestablish = closing_read_peer_msg(tmpctx, cs, channel_id);
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if (!fromwire_channel_reestablish(channel_reestablish, &their_channel_id,
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&next_local_commitment_number,
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&next_remote_revocation_number)) {
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peer_failed(cs, channel_id,
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"bad reestablish msg: %s %s",
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wire_type_name(fromwire_peektype(channel_reestablish)),
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tal_hex(tmpctx, channel_reestablish));
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}
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status_trace("Got reestablish commit=%"PRIu64" revoke=%"PRIu64,
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next_local_commitment_number,
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next_remote_revocation_number);
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/* FIXME: Spec says to re-xmit funding_locked here if we haven't
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* done any updates. */
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}
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static void send_offer(struct crypto_state *cs,
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const struct channel_id *channel_id,
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const struct pubkey funding_pubkey[NUM_SIDES],
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u8 *scriptpubkey[NUM_SIDES],
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const struct bitcoin_txid *funding_txid,
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unsigned int funding_txout,
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u64 funding_satoshi,
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const u64 satoshi_out[NUM_SIDES],
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enum side funder,
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uint64_t our_dust_limit,
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uint64_t fee_to_offer)
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{
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struct bitcoin_tx *tx;
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secp256k1_ecdsa_signature our_sig;
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u8 *msg;
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/* BOLT #2:
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*
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* - MUST set `signature` to the Bitcoin signature of the close
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* transaction, as specified in [BOLT
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* #3](03-transactions.md#closing-transaction).
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*/
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tx = close_tx(tmpctx, cs, channel_id,
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scriptpubkey,
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funding_txid,
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funding_txout,
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funding_satoshi,
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satoshi_out,
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funder, fee_to_offer, our_dust_limit);
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/* BOLT #3:
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*
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* ## Closing Transaction
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*...
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* Each node offering a signature... MAY eliminate its
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* own output.
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*/
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/* (We don't do this). */
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wire_sync_write(HSM_FD,
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take(towire_hsm_sign_mutual_close_tx(NULL,
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tx,
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&funding_pubkey[REMOTE],
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funding_satoshi)));
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msg = wire_sync_read(tmpctx, HSM_FD);
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if (!fromwire_hsm_sign_tx_reply(msg, &our_sig))
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status_failed(STATUS_FAIL_HSM_IO,
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"Bad hsm_sign_mutual_close_tx reply %s",
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tal_hex(tmpctx, msg));
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status_trace("sending fee offer %"PRIu64, fee_to_offer);
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msg = towire_closing_signed(NULL, channel_id, fee_to_offer, &our_sig);
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sync_crypto_write(cs, PEER_FD, take(msg));
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}
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static void tell_master_their_offer(const secp256k1_ecdsa_signature *their_sig,
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const struct bitcoin_tx *tx)
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{
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u8 *msg = towire_closing_received_signature(NULL, their_sig, tx);
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if (!wire_sync_write(REQ_FD, take(msg)))
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status_failed(STATUS_FAIL_MASTER_IO,
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"Writing received to master: %s",
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strerror(errno));
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/* Wait for master to ack, to make sure it's in db. */
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msg = wire_sync_read(NULL, REQ_FD);
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if (!fromwire_closing_received_signature_reply(msg))
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master_badmsg(WIRE_CLOSING_RECEIVED_SIGNATURE_REPLY, msg);
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tal_free(msg);
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}
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/* Returns fee they offered. */
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static uint64_t receive_offer(struct crypto_state *cs,
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const struct channel_id *channel_id,
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const struct pubkey funding_pubkey[NUM_SIDES],
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const u8 *funding_wscript,
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u8 *scriptpubkey[NUM_SIDES],
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const struct bitcoin_txid *funding_txid,
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unsigned int funding_txout,
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u64 funding_satoshi,
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const u64 satoshi_out[NUM_SIDES],
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enum side funder,
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uint64_t our_dust_limit,
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u64 min_fee_to_accept)
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{
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u8 *msg;
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struct channel_id their_channel_id;
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u64 received_fee;
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secp256k1_ecdsa_signature their_sig;
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struct bitcoin_tx *tx;
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/* Wait for them to say something interesting */
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do {
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msg = closing_read_peer_msg(tmpctx, cs, channel_id);
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/* BOLT #2:
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*
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* - upon reconnection:
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* - MUST ignore any redundant `funding_locked` it receives.
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*/
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/* This should only happen if we've made no commitments, but
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* we don't have to check that: it's their problem. */
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if (fromwire_peektype(msg) == WIRE_FUNDING_LOCKED)
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msg = tal_free(msg);
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/* BOLT #2:
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* - if it has sent a previous `shutdown`:
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* - MUST retransmit `shutdown`.
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*/
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else if (fromwire_peektype(msg) == WIRE_SHUTDOWN)
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msg = tal_free(msg);
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} while (!msg);
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if (!fromwire_closing_signed(msg, &their_channel_id,
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&received_fee, &their_sig))
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peer_failed(cs, channel_id,
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"Expected closing_signed: %s",
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tal_hex(tmpctx, msg));
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/* BOLT #2:
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*
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* The receiving node:
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* - if the `signature` is not valid for either variant of close
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* transaction specified in [BOLT #3](03-transactions.md#closing-transaction):
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* - MUST fail the connection.
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*/
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tx = close_tx(tmpctx, cs, channel_id,
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scriptpubkey,
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funding_txid,
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funding_txout,
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funding_satoshi,
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satoshi_out, funder, received_fee, our_dust_limit);
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if (!check_tx_sig(tx, 0, NULL, funding_wscript,
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&funding_pubkey[REMOTE], &their_sig)) {
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/* Trim it by reducing their output to minimum */
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struct bitcoin_tx *trimmed;
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u64 trimming_satoshi_out[NUM_SIDES];
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if (funder == REMOTE)
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trimming_satoshi_out[REMOTE] = received_fee;
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else
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trimming_satoshi_out[REMOTE] = 0;
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trimming_satoshi_out[LOCAL] = satoshi_out[LOCAL];
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/* BOLT #3:
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*
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* Each node offering a signature:
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* - MUST round each output down to whole satoshis.
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* - MUST subtract the fee given by `fee_satoshis` from the
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* output to the funder.
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* - MUST remove any output below its own
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* `dust_limit_satoshis`.
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* - MAY eliminate its own output.
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*/
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trimmed = close_tx(tmpctx, cs, channel_id,
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scriptpubkey,
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funding_txid,
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funding_txout,
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funding_satoshi,
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trimming_satoshi_out,
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funder, received_fee, our_dust_limit);
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if (!trimmed
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|| !check_tx_sig(trimmed, 0, NULL, funding_wscript,
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&funding_pubkey[REMOTE], &their_sig)) {
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peer_failed(cs, channel_id,
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"Bad closing_signed signature for"
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" %s (and trimmed version %s)",
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type_to_string(tmpctx,
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struct bitcoin_tx,
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tx),
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trimmed ?
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type_to_string(tmpctx,
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struct bitcoin_tx,
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trimmed)
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: "NONE");
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}
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tx = trimmed;
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}
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status_trace("Received fee offer %"PRIu64, received_fee);
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/* Master sorts out what is best offer, we just tell it any above min */
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if (received_fee >= min_fee_to_accept) {
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status_trace("...offer is reasonable");
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tell_master_their_offer(&their_sig, tx);
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}
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return received_fee;
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}
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struct feerange {
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enum side higher_side;
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u64 min, max;
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};
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static void init_feerange(struct feerange *feerange,
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u64 commitment_fee,
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const u64 offer[NUM_SIDES])
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{
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feerange->min = 0;
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/* BOLT #2:
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*
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* - MUST set `fee_satoshis` less than or equal to the base
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* fee of the final commitment transaction, as calculated
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* in [BOLT #3](03-transactions.md#fee-calculation).
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*/
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feerange->max = commitment_fee;
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if (offer[LOCAL] > offer[REMOTE])
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feerange->higher_side = LOCAL;
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else
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feerange->higher_side = REMOTE;
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status_trace("Feerange init %"PRIu64"-%"PRIu64", %s higher",
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feerange->min, feerange->max,
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feerange->higher_side == LOCAL ? "local" : "remote");
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}
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static void adjust_feerange(struct feerange *feerange,
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u64 offer, enum side side)
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{
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/* BOLT #2:
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*
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* - MUST propose a value "strictly between" the received
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* `fee_satoshis` and its previously-sent `fee_satoshis`.
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*/
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if (side == feerange->higher_side)
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feerange->max = offer - 1;
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else
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feerange->min = offer + 1;
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status_trace("Feerange %s update %"PRIu64": now %"PRIu64"-%"PRIu64,
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side == LOCAL ? "local" : "remote",
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offer, feerange->min, feerange->max);
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}
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/* Figure out what we should offer now. */
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static u64 adjust_offer(struct crypto_state *cs,
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const struct channel_id *channel_id,
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const struct feerange *feerange,
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u64 remote_offer,
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u64 min_fee_to_accept)
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{
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/* Within 1 satoshi? Agree. */
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if (feerange->min + 1 >= feerange->max)
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return remote_offer;
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/* Max is below our minimum acceptable? */
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if (feerange->max < min_fee_to_accept)
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peer_failed(cs, channel_id,
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"Feerange %"PRIu64"-%"PRIu64
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" below minimum acceptable %"PRIu64,
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feerange->min, feerange->max,
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min_fee_to_accept);
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/* Bisect between our minimum and max. */
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if (feerange->min > min_fee_to_accept)
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min_fee_to_accept = feerange->min;
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return (feerange->max + min_fee_to_accept)/2;
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}
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int main(int argc, char *argv[])
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{
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setup_locale();
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struct crypto_state cs;
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const tal_t *ctx = tal(NULL, char);
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u8 *msg;
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struct pubkey funding_pubkey[NUM_SIDES];
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struct bitcoin_txid funding_txid;
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u16 funding_txout;
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u64 funding_satoshi, satoshi_out[NUM_SIDES];
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u64 our_dust_limit;
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u64 min_fee_to_accept, commitment_fee, offer[NUM_SIDES];
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struct feerange feerange;
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enum side funder;
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u8 *scriptpubkey[NUM_SIDES], *funding_wscript;
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struct channel_id channel_id;
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bool reconnected;
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u64 next_index[NUM_SIDES], revocations_received;
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enum side whose_turn;
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u8 *channel_reestablish;
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subdaemon_setup(argc, argv);
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status_setup_sync(REQ_FD);
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msg = wire_sync_read(tmpctx, REQ_FD);
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if (!fromwire_closing_init(ctx, msg,
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&cs,
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&funding_txid, &funding_txout,
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&funding_satoshi,
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&funding_pubkey[LOCAL],
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&funding_pubkey[REMOTE],
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&funder,
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&satoshi_out[LOCAL],
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&satoshi_out[REMOTE],
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&our_dust_limit,
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&min_fee_to_accept, &commitment_fee,
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&offer[LOCAL],
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&scriptpubkey[LOCAL],
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&scriptpubkey[REMOTE],
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&reconnected,
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&next_index[LOCAL],
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&next_index[REMOTE],
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&revocations_received,
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&channel_reestablish))
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master_badmsg(WIRE_CLOSING_INIT, msg);
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status_trace("satoshi_out = %"PRIu64"/%"PRIu64,
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satoshi_out[LOCAL], satoshi_out[REMOTE]);
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status_trace("dustlimit = %"PRIu64, our_dust_limit);
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status_trace("fee = %"PRIu64, offer[LOCAL]);
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derive_channel_id(&channel_id, &funding_txid, funding_txout);
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funding_wscript = bitcoin_redeem_2of2(ctx,
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&funding_pubkey[LOCAL],
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&funding_pubkey[REMOTE]);
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if (reconnected)
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do_reconnect(&cs, &channel_id,
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next_index, revocations_received,
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channel_reestablish);
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peer_billboard(true, "Negotiating closing fee between %"PRIu64
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" and %"PRIu64" satoshi (ideal %"PRIu64")",
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min_fee_to_accept, commitment_fee, offer[LOCAL]);
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/* BOLT #2:
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*
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* The funding node:
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* - after `shutdown` has been received, AND no HTLCs remain in either
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* commitment transaction:
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* - SHOULD send a `closing_signed` message.
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|
*/
|
|
whose_turn = funder;
|
|
for (size_t i = 0; i < 2; i++, whose_turn = !whose_turn) {
|
|
if (whose_turn == LOCAL) {
|
|
send_offer(&cs,
|
|
&channel_id, funding_pubkey,
|
|
scriptpubkey, &funding_txid, funding_txout,
|
|
funding_satoshi, satoshi_out, funder,
|
|
our_dust_limit,
|
|
offer[LOCAL]);
|
|
} else {
|
|
if (i == 0)
|
|
peer_billboard(false, "Waiting for their initial"
|
|
" closing fee offer");
|
|
else
|
|
peer_billboard(false, "Waiting for their initial"
|
|
" closing fee offer:"
|
|
" ours was %"PRIu64" satoshi",
|
|
offer[LOCAL]);
|
|
offer[REMOTE]
|
|
= receive_offer(&cs,
|
|
&channel_id, funding_pubkey,
|
|
funding_wscript,
|
|
scriptpubkey, &funding_txid,
|
|
funding_txout, funding_satoshi,
|
|
satoshi_out, funder,
|
|
our_dust_limit,
|
|
min_fee_to_accept);
|
|
}
|
|
}
|
|
|
|
/* Now we have first two points, we can init fee range. */
|
|
init_feerange(&feerange, commitment_fee, offer);
|
|
|
|
/* Apply (and check) funder offer now. */
|
|
adjust_feerange(&feerange, offer[funder], funder);
|
|
|
|
/* Now any extra rounds required. */
|
|
while (offer[LOCAL] != offer[REMOTE]) {
|
|
/* Still don't agree: adjust feerange based on previous offer */
|
|
adjust_feerange(&feerange,
|
|
offer[!whose_turn], !whose_turn);
|
|
|
|
if (whose_turn == LOCAL) {
|
|
offer[LOCAL] = adjust_offer(&cs,
|
|
&channel_id,
|
|
&feerange, offer[REMOTE],
|
|
min_fee_to_accept);
|
|
send_offer(&cs, &channel_id,
|
|
funding_pubkey,
|
|
scriptpubkey, &funding_txid, funding_txout,
|
|
funding_satoshi, satoshi_out, funder,
|
|
our_dust_limit,
|
|
offer[LOCAL]);
|
|
} else {
|
|
peer_billboard(false, "Waiting for another"
|
|
" closing fee offer:"
|
|
" ours was %"PRIu64" satoshi,"
|
|
" theirs was %"PRIu64" satoshi,",
|
|
offer[LOCAL], offer[REMOTE]);
|
|
offer[REMOTE]
|
|
= receive_offer(&cs, &channel_id,
|
|
funding_pubkey,
|
|
funding_wscript,
|
|
scriptpubkey, &funding_txid,
|
|
funding_txout, funding_satoshi,
|
|
satoshi_out, funder,
|
|
our_dust_limit,
|
|
min_fee_to_accept);
|
|
}
|
|
|
|
whose_turn = !whose_turn;
|
|
}
|
|
|
|
peer_billboard(true, "We agreed on a closing fee of %"PRIu64" satoshi",
|
|
offer[LOCAL]);
|
|
|
|
/* We're done! */
|
|
/* Properly close the channel first. */
|
|
if (!socket_close(PEER_FD))
|
|
status_unusual("Closing and draining peerfd gave error: %s",
|
|
strerror(errno));
|
|
/* Sending the below will kill us! */
|
|
wire_sync_write(REQ_FD, take(towire_closing_complete(NULL)));
|
|
tal_free(ctx);
|
|
daemon_shutdown();
|
|
|
|
return 0;
|
|
}
|
|
|