From af9d763763aaced1f45564bc3ed1f3affcbf7bae Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Fri, 18 Aug 2017 14:13:53 +0930
Subject: [PATCH] bitcoin/script: support variants where we only have the
 ripemd.

For space saving, we only keep the ripemd160 for old HTLCs.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 bitcoin/script.c | 58 +++++++++++++++++++++++++++++++++++-------------
 bitcoin/script.h | 14 ++++++++++++
 2 files changed, 57 insertions(+), 15 deletions(-)

diff --git a/bitcoin/script.c b/bitcoin/script.c
index e93141316..3c0e2f6e6 100644
--- a/bitcoin/script.c
+++ b/bitcoin/script.c
@@ -708,11 +708,11 @@ u8 **bitcoin_to_local_spend_revocation(const tal_t *ctx,
  *         OP_ENDIF
  *     OP_ENDIF
  */
-u8 *bitcoin_wscript_htlc_offer(const tal_t *ctx,
-			       const struct pubkey *localkey,
-			       const struct pubkey *remotekey,
-			       const struct sha256 *payment_hash,
-			       const struct pubkey *revocationkey)
+u8 *bitcoin_wscript_htlc_offer_ripemd160(const tal_t *ctx,
+					 const struct pubkey *localkey,
+					 const struct pubkey *remotekey,
+					 const struct ripemd160 *payment_ripemd,
+					 const struct pubkey *revocationkey)
 {
 	u8 *script = tal_arr(ctx, u8, 0);
 	struct ripemd160 ripemd;
@@ -739,8 +739,8 @@ u8 *bitcoin_wscript_htlc_offer(const tal_t *ctx,
 	add_op(&script, OP_CHECKMULTISIG);
 	add_op(&script, OP_ELSE);
 	add_op(&script, OP_HASH160);
-	ripemd160(&ripemd, payment_hash->u.u8, sizeof(payment_hash->u));
-	add_push_bytes(&script, ripemd.u.u8, sizeof(ripemd.u.u8));
+	add_push_bytes(&script,
+		       payment_ripemd->u.u8, sizeof(payment_ripemd->u.u8));
 	add_op(&script, OP_EQUALVERIFY);
 	add_op(&script, OP_CHECKSIG);
 	add_op(&script, OP_ENDIF);
@@ -749,6 +749,19 @@ u8 *bitcoin_wscript_htlc_offer(const tal_t *ctx,
 	return script;
 }
 
+u8 *bitcoin_wscript_htlc_offer(const tal_t *ctx,
+			       const struct pubkey *localkey,
+			       const struct pubkey *remotekey,
+			       const struct sha256 *payment_hash,
+			       const struct pubkey *revocationkey)
+{
+	struct ripemd160 ripemd;
+
+	ripemd160(&ripemd, payment_hash->u.u8, sizeof(payment_hash->u));
+	return bitcoin_wscript_htlc_offer_ripemd160(ctx, localkey, remotekey,
+						    &ripemd, revocationkey);
+}
+
 /* BOLT #3:
  *
  * #### Received HTLC Outputs
@@ -775,12 +788,12 @@ u8 *bitcoin_wscript_htlc_offer(const tal_t *ctx,
  *         OP_ENDIF
  *     OP_ENDIF
  */
-u8 *bitcoin_wscript_htlc_receive(const tal_t *ctx,
-				 const struct abs_locktime *htlc_abstimeout,
-				 const struct pubkey *localkey,
-				 const struct pubkey *remotekey,
-				 const struct sha256 *payment_hash,
-				 const struct pubkey *revocationkey)
+u8 *bitcoin_wscript_htlc_receive_ripemd(const tal_t *ctx,
+					const struct abs_locktime *htlc_abstimeout,
+					const struct pubkey *localkey,
+					const struct pubkey *remotekey,
+					const struct ripemd160 *payment_ripemd,
+					const struct pubkey *revocationkey)
 {
 	u8 *script = tal_arr(ctx, u8, 0);
 	struct ripemd160 ripemd;
@@ -800,8 +813,8 @@ u8 *bitcoin_wscript_htlc_receive(const tal_t *ctx,
 	add_op(&script, OP_EQUAL);
 	add_op(&script, OP_IF);
 	add_op(&script, OP_HASH160);
-	ripemd160(&ripemd, payment_hash->u.u8, sizeof(payment_hash->u));
-	add_push_bytes(&script, ripemd.u.u8, sizeof(ripemd.u.u8));
+	add_push_bytes(&script,
+		       payment_ripemd->u.u8, sizeof(payment_ripemd->u.u8));
 	add_op(&script, OP_EQUALVERIFY);
 	add_number(&script, 2);
 	add_op(&script, OP_SWAP);
@@ -820,6 +833,21 @@ u8 *bitcoin_wscript_htlc_receive(const tal_t *ctx,
 	return script;
 }
 
+u8 *bitcoin_wscript_htlc_receive(const tal_t *ctx,
+				 const struct abs_locktime *htlc_abstimeout,
+				 const struct pubkey *localkey,
+				 const struct pubkey *remotekey,
+				 const struct sha256 *payment_hash,
+				 const struct pubkey *revocationkey)
+{
+	struct ripemd160 ripemd;
+
+	ripemd160(&ripemd, payment_hash->u.u8, sizeof(payment_hash->u));
+	return bitcoin_wscript_htlc_receive_ripemd(ctx, htlc_abstimeout,
+						   localkey, remotekey,
+						   &ripemd, revocationkey);
+}
+
 /* BOLT #3:
  *
  * ## HTLC-Timeout and HTLC-Success Transactions
diff --git a/bitcoin/script.h b/bitcoin/script.h
index 378389685..42b2eebbc 100644
--- a/bitcoin/script.h
+++ b/bitcoin/script.h
@@ -11,6 +11,7 @@ struct bitcoin_tx_input;
 struct preimage;
 struct pubkey;
 struct sha256;
+struct ripemd160;
 struct rel_locktime;
 struct abs_locktime;
 
@@ -141,6 +142,19 @@ u8 **bitcoin_htlc_receive_spend_preimage(const tal_t *ctx,
 				const struct preimage *preimage,
 				const u8 *wscript);
 
+/* Underlying functions for penalties, where we only keep ripemd160 */
+u8 *bitcoin_wscript_htlc_offer_ripemd160(const tal_t *ctx,
+					 const struct pubkey *localkey,
+					 const struct pubkey *remotekey,
+					 const struct ripemd160 *payment_ripemd,
+					 const struct pubkey *revocationkey);
+u8 *bitcoin_wscript_htlc_receive_ripemd(const tal_t *ctx,
+					const struct abs_locktime *htlc_abstimeout,
+					const struct pubkey *localkey,
+					const struct pubkey *remotekey,
+					const struct ripemd160 *payment_ripemd,
+					const struct pubkey *revocationkey);
+
 /* BOLT #3 HTLC-success/HTLC-timeout output */
 u8 *bitcoin_wscript_htlc_tx(const tal_t *ctx,
 			    u16 to_self_delay,