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42a38b9808
v2 of channel open uses the channel revocation basepoints to calculate the channel_id, instead of the funding_txid + outnum Moving away from the funding_txid opens the way for splicing + rbf
61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
#include <bitcoin/pubkey.h>
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#include <bitcoin/tx.h>
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#include <common/channel_id.h>
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#include <common/type_to_string.h>
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#include <wire/wire.h>
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void derive_channel_id(struct channel_id *channel_id,
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const struct bitcoin_txid *txid, u16 txout)
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{
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BUILD_ASSERT(sizeof(*channel_id) == sizeof(*txid));
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memcpy(channel_id, txid, sizeof(*channel_id));
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channel_id->id[sizeof(*channel_id)-2] ^= txout >> 8;
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channel_id->id[sizeof(*channel_id)-1] ^= txout;
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}
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void derive_channel_id_v2(struct channel_id *channel_id,
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const struct pubkey *basepoint_1,
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const struct pubkey *basepoint_2)
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{
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/* BOLT-df8bb5994d99e4c78053f7cb57694795f8393dc5 #2:
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* `channel_id`, v2
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* For channels established using the v2 protocol, the
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* `channel_id` is the
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* SHA256(lesser-revocation-basepoint ||
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* greater-revocation-basepoint),
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* where the lesser and greater is based off the order of
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* the basepoint. The basepoints are compact
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* DER-encoded public keys.
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*/
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u8 der_keys[PUBKEY_CMPR_LEN * 2];
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struct sha256 sha;
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int offset_1, offset_2;
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/* basepoint_1 is first? */
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if (pubkey_idx(basepoint_1, basepoint_2) == 0) {
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offset_1 = 0;
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offset_2 = PUBKEY_CMPR_LEN;
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} else {
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offset_1 = PUBKEY_CMPR_LEN;
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offset_2 = 0;
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}
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pubkey_to_der(der_keys + offset_1, basepoint_1);
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pubkey_to_der(der_keys + offset_2, basepoint_2);
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sha256(&sha, der_keys, sizeof(der_keys));
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BUILD_ASSERT(sizeof(*channel_id) == sizeof(sha));
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memcpy(channel_id, &sha, sizeof(*channel_id));
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}
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void towire_channel_id(u8 **pptr, const struct channel_id *channel_id)
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{
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towire(pptr, channel_id, sizeof(*channel_id));
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}
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void fromwire_channel_id(const u8 **cursor, size_t *max,
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struct channel_id *channel_id)
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{
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fromwire(cursor, max, channel_id, sizeof(*channel_id));
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}
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REGISTER_TYPE_TO_HEXSTR(channel_id);
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