protocol: add output script to close_clearing message.

We just use a p2sh to a single address for the moment, but that's simply for
non-segwit wallets; we'll pay to whatever the other side specifies.

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

close_tx.c

@@ -1,6 +1,4 @@
-#include "bitcoin/pubkey.h"
 #include "bitcoin/script.h"
-#include "bitcoin/shadouble.h"
 #include "bitcoin/tx.h"
 #include "close_tx.h"
 #include "permute_tx.h"
@@ -8,15 +6,14 @@
 
 struct bitcoin_tx *create_close_tx(secp256k1_context *secpctx,
 				   const tal_t *ctx,
-				   const struct pubkey *our_final,
-				   const struct pubkey *their_final,
+				   const u8 *our_script,
+				   const u8 *their_script,
 				   const struct sha256_double *anchor_txid,
 				   unsigned int anchor_index,
 				   u64 anchor_satoshis,
 				   uint64_t to_us, uint64_t to_them)
 {
 	struct bitcoin_tx *tx;
-	const u8 *redeemscript;
 
 	/* Now create close tx: one input, two outputs. */
 	tx = bitcoin_tx(ctx, 1, 2);
@@ -28,14 +25,15 @@ struct bitcoin_tx *create_close_tx(secp256k1_context *secpctx,
 
 	/* One output is to us. */
 	tx->output[0].amount = to_us;
-	redeemscript = bitcoin_redeem_single(tx, our_final);
-	tx->output[0].script = scriptpubkey_p2sh(tx, redeemscript);
+	tx->output[0].script = tal_dup_arr(tx, u8,
+					   our_script, tal_count(our_script), 0);
 	tx->output[0].script_length = tal_count(tx->output[0].script);
 
 	/* Other output is to them. */
 	tx->output[1].amount = to_them;
-	redeemscript = bitcoin_redeem_single(tx, their_final);
-	tx->output[1].script = scriptpubkey_p2sh(tx, redeemscript);
+	tx->output[1].script = tal_dup_arr(tx, u8,
+					   their_script, tal_count(their_script),
+					   0);
 	tx->output[1].script_length = tal_count(tx->output[1].script);
 
 	assert(tx->output[0].amount + tx->output[1].amount <= anchor_satoshis);

close_tx.h

@@ -12,8 +12,8 @@ struct pubkey;
  * input scriptsig. */
 struct bitcoin_tx *create_close_tx(secp256k1_context *secpctx,
 				   const tal_t *ctx,
-				   const struct pubkey *our_final,
-				   const struct pubkey *their_final,
+				   const u8 *our_script,
+				   const u8 *their_script,
 				   const struct sha256_double *anchor_txid,
 				   unsigned int anchor_index,
 				   u64 anchor_satoshis,

daemon/packets.c

@@ -388,9 +388,18 @@ void queue_pkt_err(struct peer *peer, Pkt *err)
 
 void queue_pkt_close_clearing(struct peer *peer)
 {
+	u8 *redeemscript;
 	CloseClearing *c = tal(peer, CloseClearing);
 
 	close_clearing__init(c);
+	redeemscript = bitcoin_redeem_single(c, &peer->us.finalkey);
+	peer->closing.our_script = scriptpubkey_p2sh(peer, redeemscript);
+
+	c->scriptpubkey.data = tal_dup_arr(c, u8,
+					   peer->closing.our_script,
+					   tal_count(peer->closing.our_script),
+					   0);
+	c->scriptpubkey.len = tal_count(c->scriptpubkey.data);
 
 	queue_pkt(peer, PKT__PKT_CLOSE_CLEARING, c);
 }
@@ -748,7 +757,13 @@ Pkt *accept_pkt_revocation(struct peer *peer, const Pkt *pkt)
 	
 Pkt *accept_pkt_close_clearing(struct peer *peer, const Pkt *pkt)
 {
-	/* FIXME: Reject unknown odd fields? */
+	const CloseClearing *c = pkt->close_clearing;
+
+	/* FIXME: Filter for non-standardness? */
+	peer->closing.their_script = tal_dup_arr(peer, u8,
+						 c->scriptpubkey.data,
+						 c->scriptpubkey.len, 0);
+
 	return NULL;
 }
 

daemon/peer.c

@@ -948,8 +948,8 @@ struct bitcoin_tx *peer_create_close_tx(struct peer *peer, u64 fee)
 		  cstate.b.pay_msat / 1000);
 
  	return create_close_tx(peer->dstate->secpctx, peer,
-			       &peer->us.finalkey,
-			       &peer->them.finalkey,
+			       peer->closing.our_script,
+			       peer->closing.their_script,
 			       &peer->anchor.txid,
 			       peer->anchor.index,
 			       peer->anchor.satoshis,

daemon/peer.h

@@ -170,6 +170,8 @@ struct peer {
 		struct bitcoin_signature *their_sig;
 		/* If their_sig is non-NULL, this is the fee. */
 		u64 their_fee;
+		/* scriptPubKey we/they want for closing. */
+		u8 *our_script, *their_script;
 	} closing;
 
 	/* If not INPUT_NONE, send this when we have no more HTLCs. */

lightning.pb-c.c

@@ -2017,9 +2017,29 @@ const ProtobufCMessageDescriptor update_revocation__descriptor =
   (ProtobufCMessageInit) update_revocation__init,
   NULL,NULL,NULL    /* reserved[123] */
 };
-#define close_clearing__field_descriptors NULL
-#define close_clearing__field_indices_by_name NULL
-#define close_clearing__number_ranges NULL
+static const ProtobufCFieldDescriptor close_clearing__field_descriptors[1] =
+{
+  {
+    "scriptPubkey",
+    1,
+    PROTOBUF_C_LABEL_REQUIRED,
+    PROTOBUF_C_TYPE_BYTES,
+    0,   /* quantifier_offset */
+    offsetof(CloseClearing, scriptpubkey),
+    NULL,
+    NULL,
+    0,             /* flags */
+    0,NULL,NULL    /* reserved1,reserved2, etc */
+  },
+};
+static const unsigned close_clearing__field_indices_by_name[] = {
+  0,   /* field[0] = scriptPubkey */
+};
+static const ProtobufCIntRange close_clearing__number_ranges[1 + 1] =
+{
+  { 1, 0 },
+  { 0, 1 }
+};
 const ProtobufCMessageDescriptor close_clearing__descriptor =
 {
   PROTOBUF_C__MESSAGE_DESCRIPTOR_MAGIC,
@@ -2028,10 +2048,10 @@ const ProtobufCMessageDescriptor close_clearing__descriptor =
   "CloseClearing",
   "",
   sizeof(CloseClearing),
-  0,
+  1,
   close_clearing__field_descriptors,
   close_clearing__field_indices_by_name,
-  0,  close_clearing__number_ranges,
+  1,  close_clearing__number_ranges,
   (ProtobufCMessageInit) close_clearing__init,
   NULL,NULL,NULL    /* reserved[123] */
 };

lightning.pb-c.h

@@ -417,10 +417,14 @@ struct  _UpdateRevocation
 struct  _CloseClearing
 {
   ProtobufCMessage base;
+  /*
+   * Output script for mutual close tx.
+   */
+  ProtobufCBinaryData scriptpubkey;
 };
 #define CLOSE_CLEARING__INIT \
  { PROTOBUF_C_MESSAGE_INIT (&close_clearing__descriptor) \
-     }
+    , {0,NULL} }
 
 
 struct  _CloseSignature

lightning.proto

@@ -173,6 +173,8 @@ message update_revocation {
 
 // Start clearing out the channel HTLCs so we can close it
 message close_clearing {
+  // Output script for mutual close tx.
+  required bytes scriptPubkey = 1;
 }
 
 message close_signature {