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#include <bitcoin/pubkey.h>
#include <bitcoin/tx.h>
#include <common/channel_id.h>
#include <common/pseudorand.h>
#include <common/type_to_string.h>
#include <wire/wire.h>
void derive_channel_id(struct channel_id *channel_id,
const struct bitcoin_txid *txid, u16 txout)
{
BUILD_ASSERT(sizeof(*channel_id) == sizeof(*txid));
memcpy(channel_id, txid, sizeof(*channel_id));
channel_id->id[sizeof(*channel_id)-2] ^= txout >> 8;
channel_id->id[sizeof(*channel_id)-1] ^= txout;
}
void derive_channel_id_v2(struct channel_id *channel_id,
const struct pubkey *basepoint_1,
const struct pubkey *basepoint_2)
{
/* BOLT-df8bb5994d99e4c78053f7cb57694795f8393dc5 #2:
* `channel_id`, v2
* For channels established using the v2 protocol, the
* `channel_id` is the
* SHA256(lesser-revocation-basepoint ||
* greater-revocation-basepoint),
* where the lesser and greater is based off the order of
* the basepoint. The basepoints are compact
* DER-encoded public keys.
*/
u8 der_keys[PUBKEY_CMPR_LEN * 2];
struct sha256 sha;
int offset_1, offset_2;
/* basepoint_1 is first? */
if (pubkey_idx(basepoint_1, basepoint_2) == 0) {
offset_1 = 0;
offset_2 = PUBKEY_CMPR_LEN;
} else {
offset_1 = PUBKEY_CMPR_LEN;
offset_2 = 0;
}
pubkey_to_der(der_keys + offset_1, basepoint_1);
pubkey_to_der(der_keys + offset_2, basepoint_2);
sha256(&sha, der_keys, sizeof(der_keys));
BUILD_ASSERT(sizeof(*channel_id) == sizeof(sha));
memcpy(channel_id, &sha, sizeof(*channel_id));
}
/* BOLT #2:
*
* The sending node:
*...
* - MUST ensure `temporary_channel_id` is unique from any other channel ID
* with the same peer.
*/
void temporary_channel_id(struct channel_id *channel_id)
{
size_t i;
/* Randomness FTW. */
for (i = 0; i < sizeof(*channel_id); i++)
channel_id->id[i] = pseudorand(256);
}
void towire_channel_id(u8 **pptr, const struct channel_id *channel_id)
{
towire(pptr, channel_id, sizeof(*channel_id));
}
void fromwire_channel_id(const u8 **cursor, size_t *max,
struct channel_id *channel_id)
{
fromwire(cursor, max, channel_id, sizeof(*channel_id));
}
REGISTER_TYPE_TO_HEXSTR(channel_id);