void queue_pkt_close_signature(struct peer *peer)
{
CloseSignature *c = tal(peer, CloseSignature);
struct bitcoin_tx *close_tx;
struct signature our_close_sig;
close_signature__init(c);
close_tx = peer_create_close_tx(peer, peer->closing.our_fee);
peer_sign_mutual_close(peer, close_tx, &our_close_sig);
c->sig = signature_to_proto(c, peer->dstate->secpctx, &our_close_sig);
c->close_fee = peer->closing.our_fee;
log_info(peer->log, "queue_pkt_close_signature: offered close fee %"
PRIu64, c->close_fee);
queue_pkt(peer, PKT__PKT_CLOSE_SIGNATURE, c);
}
Pkt *accept_pkt_close_sig(struct peer *peer, const Pkt *pkt, bool *acked,
bool *we_agree)
{
const CloseSignature *c = pkt->close_signature;
struct bitcoin_tx *close_tx;
struct bitcoin_signature theirsig;
log_info(peer->log, "accept_pkt_close_sig: they offered close fee %"
PRIu64, c->close_fee);
*acked = *we_agree = false;
/* BOLT #2:
*
* The sender MUST set `close_fee` lower than or equal to the fee of the
* final commitment transaction, and MUST set `close_fee` to an even
* number of satoshis.
*/
if ((c->close_fee & 1)
|| c->close_fee > commit_tx_fee(peer->them.commit->tx,
peer->anchor.satoshis)) {
return pkt_err(peer, "Invalid close fee");
}
/* FIXME: Don't accept tiny fee at all? */
/* BOLT #2:
... otherwise it SHOULD propose a
value strictly between the received `close_fee` and its
previously-sent `close_fee`.
*/
if (peer->closing.their_sig) {
/* We want more, they should give more. */
if (peer->closing.our_fee > peer->closing.their_fee) {
if (c->close_fee <= peer->closing.their_fee)
return pkt_err(peer, "Didn't increase close fee");
} else {
if (c->close_fee >= peer->closing.their_fee)
return pkt_err(peer, "Didn't decrease close fee");
}
}
/* BOLT #2:
*
* The receiver MUST check `sig` is valid for the close
* transaction, and MUST fail the connection if it is not. */
theirsig.stype = SIGHASH_ALL;
if (!proto_to_signature(c->sig, &theirsig.sig))
return pkt_err(peer, "Invalid signature format");
close_tx = peer_create_close_tx(peer, c->close_fee);
if (!check_tx_sig(peer->dstate->secpctx, close_tx, 0,
NULL, 0,
peer->anchor.witnessscript,
&peer->them.commitkey, &theirsig))
return pkt_err(peer, "Invalid signature");
tal_free(peer->closing.their_sig);
peer->closing.their_sig = tal_dup(peer,
struct bitcoin_signature, &theirsig);
peer->closing.their_fee = c->close_fee;
if (peer->closing.our_fee == peer->closing.their_fee) {
log_info(peer->log, "accept_pkt_close_sig: That's an ack");
*acked = true;
} else {
/* Adjust our fee to close on their fee. */
u64 sum;
/* Beware overflow! */
sum = (u64)peer->closing.our_fee + peer->closing.their_fee;
peer->closing.our_fee = sum / 2;
if (peer->closing.our_fee & 1)
peer->closing.our_fee++;
log_info(peer->log, "accept_pkt_close_sig: we change to %"PRIu64,
peer->closing.our_fee);
/* Corner case: we may now agree with them. */
if (peer->closing.our_fee == peer->closing.their_fee)
*we_agree = true;
}
/* FIXME: Dynamic fee! */
return NULL;
}