core-lightning/commit_tx.c
Rusty Russell cc4fc4b668 daemon: use htlc pointers everywhere.
No more copies!

I tried changing the cstate->side[].htlcs to htlc_map rather than a
simple pointer array, but we rely on those array indices heavily for
permutation mapping, and it turned into a major rewrite (especially
for the steal case).

Eventually, we're going to want to reconstruct the commit info for
older commit txs rather than keeping all the permutation and
per-commit-info HTLC information in memory, so we can do the work
then.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2016-07-01 12:00:17 +09:30

122 lines
3.8 KiB
C

#include "bitcoin/locktime.h"
#include "bitcoin/pubkey.h"
#include "bitcoin/script.h"
#include "bitcoin/shadouble.h"
#include "bitcoin/tx.h"
#include "commit_tx.h"
#include "daemon/channel.h"
#include "overflows.h"
#include "permute_tx.h"
#include "remove_dust.h"
#include <assert.h>
static bool add_htlc(struct bitcoin_tx *tx, size_t n,
const struct htlc *h,
const struct pubkey *ourkey,
const struct pubkey *theirkey,
const struct sha256 *rhash,
const struct rel_locktime *locktime,
u8 *(*scriptpubkeyfn)(const tal_t *,
const struct pubkey *,
const struct pubkey *,
const struct abs_locktime *,
const struct rel_locktime *,
const struct sha256 *,
const struct sha256 *))
{
assert(!tx->output[n].script);
tx->output[n].script = scriptpubkey_p2wsh(tx,
scriptpubkeyfn(tx, ourkey, theirkey,
&h->expiry, locktime, rhash,
&h->rhash));
tx->output[n].script_length = tal_count(tx->output[n].script);
tx->output[n].amount = h->msatoshis / 1000;
return true;
}
struct bitcoin_tx *create_commit_tx(const tal_t *ctx,
const struct pubkey *our_final,
const struct pubkey *their_final,
const struct rel_locktime *our_locktime,
const struct rel_locktime *their_locktime,
const struct sha256_double *anchor_txid,
unsigned int anchor_index,
u64 anchor_satoshis,
const struct sha256 *rhash,
const struct channel_state *cstate,
enum channel_side side,
int **map)
{
struct bitcoin_tx *tx;
const u8 *redeemscript;
size_t i, num;
uint64_t total;
const struct pubkey *self, *other;
const struct rel_locktime *locktime;
/* Now create commitment tx: one input, two outputs (plus htlcs) */
tx = bitcoin_tx(ctx, 1, 2 + tal_count(cstate->side[OURS].htlcs)
+ tal_count(cstate->side[THEIRS].htlcs));
/* Our input spends the anchor tx output. */
tx->input[0].txid = *anchor_txid;
tx->input[0].index = anchor_index;
tx->input[0].amount = tal_dup(tx->input, u64, &anchor_satoshis);
/* For our commit tx, our payment is delayed by amount they said */
if (side == OURS) {
self = our_final;
other = their_final;
locktime = their_locktime;
} else {
self = their_final;
other = our_final;
locktime = our_locktime;
}
/* First output is a P2WSH to a complex redeem script
* (usu. for this side) */
redeemscript = bitcoin_redeem_secret_or_delay(tx, self,
locktime,
other,
rhash);
tx->output[0].script = scriptpubkey_p2wsh(tx, redeemscript);
tx->output[0].script_length = tal_count(tx->output[0].script);
tx->output[0].amount = cstate->side[side].pay_msat / 1000;
/* Second output is a P2WPKH payment to other side. */
tx->output[1].script = scriptpubkey_p2wpkh(tx, other);
tx->output[1].script_length = tal_count(tx->output[1].script);
tx->output[1].amount = cstate->side[!side].pay_msat / 1000;
/* First two outputs done, now for the HTLCs. */
total = tx->output[0].amount + tx->output[1].amount;
num = 2;
/* HTLCs this side sent. */
for (i = 0; i < tal_count(cstate->side[side].htlcs); i++) {
if (!add_htlc(tx, num, cstate->side[side].htlcs[i],
self, other, rhash, locktime,
bitcoin_redeem_htlc_send))
return tal_free(tx);
total += tx->output[num++].amount;
}
/* HTLCs this side has received. */
for (i = 0; i < tal_count(cstate->side[!side].htlcs); i++) {
if (!add_htlc(tx, num, cstate->side[!side].htlcs[i],
self, other, rhash, locktime,
bitcoin_redeem_htlc_recv))
return tal_free(tx);
total += tx->output[num++].amount;
}
assert(num == tx->output_count);
assert(total <= anchor_satoshis);
*map = tal_arr(ctx, int, tx->output_count);
permute_outputs(tx->output, tx->output_count, *map);
remove_dust(tx, *map);
return tx;
}