protocol: add revocation hash to update_accept for other commit tx.

And clarify that we're going to be closing the anchor tx directly.

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

lightning.pb-c.c

@@ -1820,7 +1820,7 @@ const ProtobufCMessageDescriptor update__descriptor =
   (ProtobufCMessageInit) update__init,
   NULL,NULL,NULL    /* reserved[123] */
 };
-static const ProtobufCFieldDescriptor update_accept__field_descriptors[3] =
+static const ProtobufCFieldDescriptor update_accept__field_descriptors[4] =
 {
   {
     "sig",
@@ -1847,11 +1847,23 @@ static const ProtobufCFieldDescriptor update_accept__field_descriptors[3] =
     0,NULL,NULL    /* reserved1,reserved2, etc */
   },
   {
-    "revocation_preimage",
+    "revocation_hash",
     3,
     PROTOBUF_C_LABEL_REQUIRED,
     PROTOBUF_C_TYPE_MESSAGE,
     0,   /* quantifier_offset */
+    offsetof(UpdateAccept, revocation_hash),
+    &sha256_hash__descriptor,
+    NULL,
+    0,             /* flags */
+    0,NULL,NULL    /* reserved1,reserved2, etc */
+  },
+  {
+    "revocation_preimage",
+    4,
+    PROTOBUF_C_LABEL_REQUIRED,
+    PROTOBUF_C_TYPE_MESSAGE,
+    0,   /* quantifier_offset */
     offsetof(UpdateAccept, revocation_preimage),
     &sha256_hash__descriptor,
     NULL,
@@ -1861,13 +1873,14 @@ static const ProtobufCFieldDescriptor update_accept__field_descriptors[3] =
 };
 static const unsigned update_accept__field_indices_by_name[] = {
   1,   /* field[1] = old_anchor_sig */
-  2,   /* field[2] = revocation_preimage */
+  2,   /* field[2] = revocation_hash */
+  3,   /* field[3] = revocation_preimage */
   0,   /* field[0] = sig */
 };
 static const ProtobufCIntRange update_accept__number_ranges[1 + 1] =
 {
   { 1, 0 },
-  { 0, 3 }
+  { 0, 4 }
 };
 const ProtobufCMessageDescriptor update_accept__descriptor =
 {
@@ -1877,7 +1890,7 @@ const ProtobufCMessageDescriptor update_accept__descriptor =
   "UpdateAccept",
   "",
   sizeof(UpdateAccept),
-  3,
+  4,
   update_accept__field_descriptors,
   update_accept__field_indices_by_name,
   1,  update_accept__number_ranges,

lightning.pb-c.h

@@ -323,6 +323,10 @@ struct  _UpdateAccept
    * Signature for old anchor (if any)
    */
   Signature *old_anchor_sig;
+  /*
+   * Hash for which I will supply preimage to revoke this new commit tx.
+   */
+  Sha256Hash *revocation_hash;
   /*
    * Hash preimage which revokes old commitment tx.
    */
@@ -330,7 +334,7 @@ struct  _UpdateAccept
 };
 #define UPDATE_ACCEPT__INIT \
  { PROTOBUF_C_MESSAGE_INIT (&update_accept__descriptor) \
-    , NULL, NULL, NULL }
+    , NULL, NULL, NULL, NULL }
 
 
 /*
@@ -426,8 +430,9 @@ struct  _CloseChannel
 {
   ProtobufCMessage base;
   /*
-   * This is our signature a new transaction which spends my current
-   * commitment tx output 0 (which is 2/2) to script_to_me.
+   * This is our signature a new transaction which spends the anchor
+   * output to my open->script_to_me and your open->script_to_me,
+   * as per the last commit tx.
    */
   Signature *sig;
 };
@@ -437,14 +442,13 @@ struct  _CloseChannel
 
 
 /*
- * OK, here's my sig so you can broadcast it too.
+ * OK, here's my sig so you can broadcast it too.  We're done.
  */
 struct  _CloseChannelComplete
 {
   ProtobufCMessage base;
   /*
-   * This is our signature a new transaction which spends your current
-   * commitment tx output 0 (which is 2/2) to your script_to_me.
+   * This is my signature for that same tx.
    */
   Signature *sig;
 };

lightning.proto

@@ -134,8 +134,10 @@ message update_accept {
   required signature sig = 1;
   // Signature for old anchor (if any)
   optional signature old_anchor_sig = 2;
+  // Hash for which I will supply preimage to revoke this new commit tx.
+  required sha256_hash revocation_hash = 3;
   // Hash preimage which revokes old commitment tx.
-  required sha256_hash revocation_preimage = 3;
+  required sha256_hash revocation_preimage = 4;
 }
 
 // Complete the update.
@@ -173,15 +175,15 @@ message new_anchor_complete {
 
 // Begin cooperative close of channel.
 message close_channel {
-  // This is our signature a new transaction which spends my current
-  // commitment tx output 0 (which is 2/2) to script_to_me.
+  // This is our signature a new transaction which spends the anchor
+  // output to my open->script_to_me and your open->script_to_me,
+  // as per the last commit tx.
   required signature sig = 1;
 }
 
-// OK, here's my sig so you can broadcast it too.
+// OK, here's my sig so you can broadcast it too.  We're done.
 message close_channel_complete {
-  // This is our signature a new transaction which spends your current
-  // commitment tx output 0 (which is 2/2) to your script_to_me.
+  // This is my signature for that same tx.
   required signature sig = 1;
 }