lightningd/commit_tx: creation of BOLT 3 commitment transaction.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/commit_tx.h

@@ -0,0 +1,41 @@
+#ifndef LIGHTNING_LIGHTNINGD_COMMIT_TX_H
+#define LIGHTNING_LIGHTNINGD_COMMIT_TX_H
+#include "config.h"
+#include <daemon/htlc.h>
+
+struct pubkey;
+struct sha256_double;
+
+/* BOLT #3:
+ *
+ * This obscures the number of commitments made on the channel in the
+ * case of unilateral close, yet still provides a useful index for
+ * both nodes (who know the payment-basepoints) to quickly find a
+ * revoked commitment transaction.
+ */
+u64 commit_number_obscurer(const struct pubkey *opener_payment_basepoint,
+			   const struct pubkey *accepter_payment_basepoint);
+
+/* commit_tx needs to know these so it knows what outputs to trim */
+u64 htlc_success_fee(u64 feerate_per_kw);
+u64 htlc_timeout_fee(u64 feerate_per_kw);
+
+/* Create commitment tx to spend the funding tx output; doesn't fill in
+ * input scriptsig. */
+struct bitcoin_tx *commit_tx(const tal_t *ctx,
+			     const struct sha256_double *funding_txid,
+			     unsigned int funding_txout,
+			     u64 funding_satoshis,
+			     enum side funder,
+			     u16 to_self_delay,
+			     const struct pubkey *revocation_pubkey,
+			     const struct pubkey *local_delayedkey,
+			     const struct pubkey *localkey,
+			     const struct pubkey *remotekey,
+			     u64 feerate_per_kw,
+			     u64 dust_limit_satoshis,
+			     u64 local_pay_msat,
+			     u64 remote_pay_msat,
+			     const struct htlc **htlcs,
+			     u64 commit_number_obscurer);
+#endif /* LIGHTNING_LIGHTNINGD_COMMIT_TX_H */