82 lines
2.5 KiB
C
82 lines
2.5 KiB
C
#include "bitcoin/pubkey.h"
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#include "bitcoin/script.h"
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#include "bitcoin/shadouble.h"
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#include "bitcoin/tx.h"
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#include "commit_tx.h"
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#include "overflows.h"
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#include "permute_tx.h"
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#include "pkt.h"
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#include "protobuf_convert.h"
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struct bitcoin_tx *create_commit_tx(const tal_t *ctx,
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OpenChannel *ours,
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OpenChannel *theirs,
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const struct sha256 *rhash,
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int64_t delta,
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const struct sha256_double *anchor_txid,
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unsigned int anchor_output)
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{
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struct bitcoin_tx *tx;
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const u8 *redeemscript;
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struct pubkey ourkey, theirkey, to_me;
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u32 locktime;
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/* Now create commitment tx: one input, two outputs. */
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tx = bitcoin_tx(ctx, 1, 2);
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/* Our input spends the anchor tx output. */
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tx->input[0].txid = *anchor_txid;
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tx->input[0].index = anchor_output;
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if (add_overflows_u64(ours->anchor->total, theirs->anchor->total))
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return tal_free(tx);
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tx->input[0].input_amount = ours->anchor->total + theirs->anchor->total;
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/* Output goes to our final pubkeys */
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if (!proto_to_pubkey(ours->final, &ourkey))
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return tal_free(tx);
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if (!proto_to_pubkey(theirs->final, &theirkey))
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return tal_free(tx);
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if (!proto_to_locktime(theirs, &locktime))
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return tal_free(tx);
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/* First output is a P2SH to a complex redeem script (usu. for me) */
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redeemscript = bitcoin_redeem_revocable(tx, &ourkey,
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locktime,
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&theirkey,
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rhash);
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tx->output[0].script = scriptpubkey_p2sh(tx, redeemscript);
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tx->output[0].script_length = tal_count(tx->output[0].script);
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if (ours->anchor->total < ours->commitment_fee)
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return tal_free(tx);
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tx->output[0].amount = ours->anchor->total - ours->commitment_fee;
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/* Asking for more than we have? */
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if (delta < 0 && -delta > tx->output[0].amount)
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return tal_free(tx);
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tx->output[0].amount += delta;
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/* Second output is a P2SH payment to them. */
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if (!proto_to_pubkey(theirs->final, &to_me))
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return tal_free(tx);
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tx->output[1].script = scriptpubkey_p2sh(ctx,
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bitcoin_redeem_single(ctx,
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&to_me));
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tx->output[1].script_length = tal_count(tx->output[1].script);
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if (theirs->anchor->total < theirs->commitment_fee)
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return tal_free(tx);
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tx->output[1].amount = theirs->anchor->total - theirs->commitment_fee;
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/* Asking for more than they have? */
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if (delta > 0 && delta > tx->output[1].amount)
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return tal_free(tx);
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tx->output[0].amount -= delta;
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/* Calculate fee; difference of inputs and outputs. */
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tx->fee = tx->input[0].input_amount
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- (tx->output[0].amount + tx->output[1].amount);
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permute_outputs(ours->seed, theirs->seed, 1, tx->output, 2, NULL);
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return tx;
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}
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