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permute: use BIP69 order.

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It's a canonical ordering, rather than a random shuffle.  Far simpler.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2015-07-20 09:56:15 +09:30
parent d93eee22f5
commit 8a4246cb36
11 changed files with 37 additions and 139 deletions
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6
anchor.c
View File

@ -127,10 +127,8 @@ struct bitcoin_tx *anchor_tx_create(const tal_t *ctx,
else
outmap = NULL;
permute_inputs(o1->seed, o2->seed, 0, tx->input, tx->input_count,
inmap);
permute_outputs(o1->seed, o2->seed, 0, tx->output, tx->output_count,
outmap);
permute_inputs(tx->input, tx->input_count, inmap);
permute_outputs(tx->output, tx->output_count, outmap);
return tx;
}

2
close_tx.c
View File

@ -55,6 +55,6 @@ struct bitcoin_tx *create_close_tx(const tal_t *ctx,
tx->output[1].script_length = tal_count(tx->output[1].script);
tx->fee = ours->commitment_fee + theirs->commitment_fee;
permute_outputs(ours->seed, theirs->seed, 1, tx->output, 2, NULL);
permute_outputs(tx->output, 2, NULL);
return tx;
}

2
commit_tx.c
View File

@ -76,6 +76,6 @@ struct bitcoin_tx *create_commit_tx(const tal_t *ctx,
tx->fee = tx->input[0].input_amount
- (tx->output[0].amount + tx->output[1].amount);
permute_outputs(ours->seed, theirs->seed, 1, tx->output, 2, NULL);
permute_outputs(tx->output, 2, NULL);
return tx;
}

35
lightning.pb-c.c
View File

@ -1474,20 +1474,8 @@ const ProtobufCMessageDescriptor anchor__descriptor =
(ProtobufCMessageInit) anchor__init,
NULL,NULL,NULL /* reserved[123] */
};
static const ProtobufCFieldDescriptor open_channel__field_descriptors[8] =
static const ProtobufCFieldDescriptor open_channel__field_descriptors[7] =
{
{
"seed",
1,
PROTOBUF_C_LABEL_REQUIRED,
PROTOBUF_C_TYPE_UINT64,
0, /* quantifier_offset */
offsetof(OpenChannel, seed),
NULL,
NULL,
0, /* flags */
0,NULL,NULL /* reserved1,reserved2, etc */
},
{
"locktime_seconds",
2,
@ -1574,19 +1562,18 @@ static const ProtobufCFieldDescriptor open_channel__field_descriptors[8] =
},
};
static const unsigned open_channel__field_indices_by_name[] = {
6, /* field[6] = anchor */
5, /* field[5] = commitment_fee */
4, /* field[4] = final */
2, /* field[2] = locktime_blocks */
1, /* field[1] = locktime_seconds */
3, /* field[3] = revocation_hash */
0, /* field[0] = seed */
7, /* field[7] = tx_version */
5, /* field[5] = anchor */
4, /* field[4] = commitment_fee */
3, /* field[3] = final */
1, /* field[1] = locktime_blocks */
0, /* field[0] = locktime_seconds */
2, /* field[2] = revocation_hash */
6, /* field[6] = tx_version */
};
static const ProtobufCIntRange open_channel__number_ranges[1 + 1] =
{
{ 1, 0 },
{ 0, 8 }
{ 2, 0 },
{ 0, 7 }
};
const ProtobufCMessageDescriptor open_channel__descriptor =
{
@ -1596,7 +1583,7 @@ const ProtobufCMessageDescriptor open_channel__descriptor =
"OpenChannel",
"",
sizeof(OpenChannel),
8,
7,
open_channel__field_descriptors,
open_channel__field_indices_by_name,
1, open_channel__number_ranges,

6
lightning.pb-c.h
View File

@ -185,10 +185,6 @@ typedef enum {
struct _OpenChannel
{
ProtobufCMessage base;
/*
* Seed which sets order we create outputs for all transactions.
*/
uint64_t seed;
/*
* Hash seed for revoking commitment transactions.
*/
@ -217,7 +213,7 @@ struct _OpenChannel
};
#define OPEN_CHANNEL__INIT \
{ PROTOBUF_C_MESSAGE_INIT (&open_channel__descriptor) \
, 0, NULL, NULL, 0, NULL, 0, OPEN_CHANNEL__LOCKTIME__NOT_SET, {} }
, NULL, NULL, 0, NULL, 0, OPEN_CHANNEL__LOCKTIME__NOT_SET, {} }
/*

2
lightning.proto
View File

@ -70,8 +70,6 @@ message anchor {
// Set channel params.
message open_channel {
// Seed which sets order we create outputs for all transactions.
required uint64 seed = 1;
// Relative locktime for outputs going to us.
oneof locktime {
uint32 locktime_seconds = 2;

95
permute_tx.c
View File

@ -1,39 +1,7 @@
#include <ccan/crypto/sha256/sha256.h>
#include <stdbool.h>
#include <string.h>
#include "permute_tx.h"
static u32 get_next_rand(struct sha256 *h, size_t *randidx)
{
u32 ret = h->u.u32[(*randidx)++];
if (*randidx == 8) {
*randidx = 0;
sha256(h, h, sizeof(*h));
}
return ret;
}
static void init_rand(struct sha256 *h, size_t *randidx,
uint64_t seed1, uint64_t seed2,
uint64_t transaction_num,
enum permute_style style)
{
struct sha256_ctx shactx;
sha256_init(&shactx);
if (seed1 < seed2) {
sha256_le64(&shactx, seed1);
sha256_le64(&shactx, seed2);
} else {
sha256_le64(&shactx, seed2);
sha256_le64(&shactx, seed1);
}
sha256_le64(&shactx, transaction_num);
sha256_u8(&shactx, style);
sha256_done(&shactx, h);
*randidx = 0;
}
static void init_map(size_t *map, size_t len)
{
size_t i;
@ -45,21 +13,6 @@ static void init_map(size_t *map, size_t len)
map[i] = i;
}
/* This map says where things ended up, eg. 0 might be in slot 3. we
* want to change it so map[0] = 3. */
static void invert_map(size_t *map, size_t len)
{
if (map) {
size_t i, newmap[len];
memset(newmap, 0, sizeof(newmap));
for (i = 0; i < len; i++) {
newmap[map[i]] = i;
}
memcpy(map, newmap, sizeof(newmap));
}
}
static bool input_better(const struct bitcoin_tx_input *a,
const struct bitcoin_tx_input *b)
{
@ -108,13 +61,11 @@ static void swap_inputs(struct bitcoin_tx_input *inputs, size_t *map,
}
}
void permute_inputs(uint64_t seed1, uint64_t seed2, uint64_t tx_num,
struct bitcoin_tx_input *inputs,
void permute_inputs(struct bitcoin_tx_input *inputs,
size_t num_inputs,
size_t *map)
{
struct sha256 h;
size_t i, randidx;
size_t i;
init_map(map, num_inputs);
@ -124,16 +75,6 @@ void permute_inputs(uint64_t seed1, uint64_t seed2, uint64_t tx_num,
swap_inputs(inputs, map,
i, i + find_best_in(inputs + i, num_inputs - i));
}
init_rand(&h, &randidx, seed1, seed2, tx_num, PERMUTE_INPUT_STYLE);
/* Now, Fisher-Yates shuffle, but using SHA256 as "random" source. */
for (i = 0; i + 1 < num_inputs; i++) {
size_t r = get_next_rand(&h, &randidx) % (num_inputs - i - 1);
swap_inputs(inputs, map, i, i + 1 + r);
}
invert_map(map, num_inputs);
}
static void swap_outputs(struct bitcoin_tx_output *outputs, size_t *map,
@ -156,13 +97,23 @@ static void swap_outputs(struct bitcoin_tx_output *outputs, size_t *map,
static bool output_better(const struct bitcoin_tx_output *a,
const struct bitcoin_tx_output *b)
{
size_t len;
int ret;
if (a->amount != b->amount)
return a->amount < b->amount;
if (a->script_length != b->script_length)
return a->script_length < b->script_length;
/* Lexographic sort. */
if (a->script_length < b->script_length)
len = a->script_length;
else
len = b->script_length;
return memcmp(a->script, b->script, a->script_length) < 0;
ret = memcmp(a->script, b->script, len);
if (ret != 0)
return ret < 0;
return a->script_length < b->script_length;
}
static size_t find_best_out(struct bitcoin_tx_output *outputs, size_t num)
@ -176,13 +127,11 @@ static size_t find_best_out(struct bitcoin_tx_output *outputs, size_t num)
return best;
}
void permute_outputs(uint64_t seed1, uint64_t seed2, size_t tx_num,
struct bitcoin_tx_output *outputs,
void permute_outputs(struct bitcoin_tx_output *outputs,
size_t num_outputs,
size_t *map)
{
struct sha256 h;
size_t i, randidx;
size_t i;
init_map(map, num_outputs);
@ -192,14 +141,4 @@ void permute_outputs(uint64_t seed1, uint64_t seed2, size_t tx_num,
swap_outputs(outputs, map,
i, i + find_best_out(outputs + i, num_outputs - i));
}
init_rand(&h, &randidx, seed1, seed2, tx_num, PERMUTE_OUTPUT_STYLE);
/* Now, Fisher-Yates shuffle, but using SHA256 as "random" source. */
for (i = 0; i + 1 < num_outputs; i++) {
size_t r = get_next_rand(&h, &randidx) % (num_outputs - i - 1);
swap_outputs(outputs, map, i, i + 1 + r);
}
invert_map(map, num_outputs);
}

16
permute_tx.h
View File

@ -2,24 +2,14 @@
#define LIGHTNING_PERMUTE_TX_H
#include "bitcoin/tx.h"
/* Given the two seeds, permute the transaction inputs.
/* Permute the transaction into BIP69 order.
* map[0] is set to the new index of input 0, etc.
*/
void permute_inputs(uint64_t seed1, uint64_t seed2,
size_t transaction_num,
struct bitcoin_tx_input *inputs,
void permute_inputs(struct bitcoin_tx_input *inputs,
size_t num_inputs,
size_t *map);
void permute_outputs(uint64_t seed1, uint64_t seed2,
size_t transaction_num,
struct bitcoin_tx_output *outputs,
void permute_outputs(struct bitcoin_tx_output *outputs,
size_t num_outputs,
size_t *map);
enum permute_style {
PERMUTE_INPUT_STYLE = 0,
PERMUTE_OUTPUT_STYLE = 1
};
#endif /* LIGHTNING_PERMUTE_TX_H */

2
pkt.c
View File

@ -32,7 +32,6 @@ static struct pkt *to_pkt(const tal_t *ctx, Pkt__PktCase type, void *msg)
}
struct pkt *openchannel_pkt(const tal_t *ctx,
u64 seed,
const struct sha256 *revocation_hash,
const struct pubkey *to_me,
u64 commitment_fee,
@ -45,7 +44,6 @@ struct pkt *openchannel_pkt(const tal_t *ctx,
assert(anchor->inputs);
assert(anchor->pubkey);
o.seed = seed;
o.revocation_hash = sha256_to_proto(ctx, revocation_hash);
o.final = pubkey_to_proto(ctx, to_me);
o.commitment_fee = commitment_fee;

2
pkt.h
View File

@ -31,7 +31,6 @@ struct pubkey;
/**
* openchannel_pkt - create an openchannel message
* @ctx: tal context to allocate off.
* @seed: psuedo-random seed to shuffle inputs.
* @revocation_hash: first hash value generated from seed.
* @to_me: the pubkey for the commit transactions' P2SH output.
* @commitment_fee: the fee to use for commitment tx.
@ -39,7 +38,6 @@ struct pubkey;
* @anchor: the anchor transaction details.
*/
struct pkt *openchannel_pkt(const tal_t *ctx,
u64 seed,
const struct sha256 *revocation_hash,
const struct pubkey *to_me,
u64 commitment_fee,

8
test-cli/open-channel.c
View File

@ -59,12 +59,6 @@ static BitcoinInput *parse_anchor_input(const tal_t *ctx, const char *spec)
return in;
}
/* FIXME: This is too weak, even for us! */
static u64 weak_random64(void)
{
return time(NULL);
}
/* Simple helper to open a channel. */
int main(int argc, char *argv[])
{
@ -166,7 +160,7 @@ int main(int argc, char *argv[])
sha256(&revocation_hash,
revocation_hash.u.u8, sizeof(revocation_hash.u.u8));
pkt = openchannel_pkt(ctx, weak_random64(), &revocation_hash, &outkey,
pkt = openchannel_pkt(ctx, &revocation_hash, &outkey,
commit_tx_fee, locktime_seconds, &anchor);
if (!write_all(STDOUT_FILENO, pkt, pkt_totlen(pkt)))