Improve Interoperability LIPs

proposals/lip-0049.md

@@ -7,7 +7,7 @@ Discussions-To: https://research.lisk.com/t/introduce-cross-chain-messages/299
 Status: Draft
 Type: Standards Track
 Created: 2021-05-22
-Updated: 2022-11-11
+Updated: 2023-01-13
 Requires: 0053
 ```
 
@@ -236,7 +236,7 @@ def validateFormat(ccm: CCM) -> None:
     if not re.match("^[a-zA-Z0-9]*$", ccm.crossChainCommand):
         raise Exception("Cross-chain message command name must be alphanumeric.")
     # Check ccm size.
-    if ccmBytes > MAX_CCM_SIZE:
+    if len(ccmBytes) > MAX_CCM_SIZE:
         raise Exception(f"Cross-chain message size is larger than {MAX_CCM_SIZE}.")
 ```
 
@@ -250,8 +250,6 @@ _Figure 1: A schematic of the steps executed in the `apply` function. Blue bored
 
 ```python
 def apply(ccu: Transaction, ccm: CCM) -> None:
-    # Calculate CCM ID, used later in events.
-    ccmID = sha256(encode(crossChainMessageSchema, ccm))
     try:
         if not isLive(ccm.sendingChainID):  
             raise Exception(f"Sending chain {ccm.sendingChainID} is not live.")
@@ -266,7 +264,7 @@ def apply(ccu: Transaction, ccm: CCM) -> None:
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_VERIFY_CCM_EXCEPTION},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_VERIFY_CCM_EXCEPTION},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
         return
@@ -286,7 +284,7 @@ def apply(ccu: Transaction, ccm: CCM) -> None:
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_VERIFY_EXCEPTION},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_VERIFY_EXCEPTION},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
         return
@@ -304,19 +302,26 @@ def apply(ccu: Transaction, ccm: CCM) -> None:
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_BEFORE_CCC_EXECUTION_EXCEPTION},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_BEFORE_CCC_EXECUTION_EXCEPTION},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
         return
     # Create a state snapshot.
     executionSnapshot = snapshot of the current state
     try:
+        # This could happen during the execution of a mainchain CCU containing a CCM 
+        # from a sidechain for which a direct channel has been registered.
+        # Then, ccu.params.sendingChainID == CHAIN_ID_MAINCHAIN.
+        # This is not necessarily a violation of the protocol, since the message
+        # could have been sent before the direct channel was opened.
+        if chainAccount(ccm.sendingChainID) exists and ccu.params.sendingChainID != ccm.sendingChainID:
+            raise Exception("Cannot receive forwarded messages for a direct channel.")
         # Execute the cross-chain command.
         crossChainCommand.execute(ccu, ccm)
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_APPLIED, "code": CCM_PROCESSED_CODE_SUCCESS},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_APPLIED, "code": CCM_PROCESSED_CODE_SUCCESS},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
     except:
@@ -333,7 +338,7 @@ def apply(ccu: Transaction, ccm: CCM) -> None:
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_AFTER_CCC_EXECUTION_EXCEPTION},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_AFTER_CCC_EXECUTION_EXCEPTION},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
 ```
@@ -348,8 +353,6 @@ _Figure 2: A schematic of the steps executed in the `forward` function. Blue bor
 
 ```python
 def forward(ccu: Transaction, ccm: CCM) -> None:
-    # Calculate CCM ID, used later in events.
-    ccmID = sha256(encode(crossChainMessageSchema, ccm))
     try:
         if not isLive(ccm.sendingChainID):  
             raise Exception(f"Sending chain {ccm.sendingChainID} is not live.")
@@ -364,7 +367,7 @@ def forward(ccu: Transaction, ccm: CCM) -> None:
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_VERIFY_CCM_EXCEPTION},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_VERIFY_CCM_EXCEPTION},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
         return
@@ -386,7 +389,7 @@ def forward(ccu: Transaction, ccm: CCM) -> None:
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_CHANNEL_UNAVAILABLE},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_CHANNEL_UNAVAILABLE},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
 
@@ -404,7 +407,7 @@ def forward(ccu: Transaction, ccm: CCM) -> None:
             ccm.sendingChainID,
             0,
             CCM_STATUS_CODE_OK,
-            stmParams
+            encode(sidechainTerminatedCCMParamsSchema, stmParams)
         )
         return
 
@@ -421,7 +424,7 @@ def forward(ccu: Transaction, ccm: CCM) -> None:
         emitEvent(
             module = MODULE_NAME_INTEROPERABILITY,
             name = EVENT_NAME_CCM_PROCESSED,
-            data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_BEFORE_CCC_FORWARDING_EXCEPTION},
+            data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_DISCARDED, "code": CCM_PROCESSED_CODE_INVALID_CCM_BEFORE_CCC_FORWARDING_EXCEPTION},
             topics = [ccm.sendingChainID, ccm.receivingChainID]
         )
         return
@@ -431,7 +434,7 @@ def forward(ccu: Transaction, ccm: CCM) -> None:
     emitEvent(
         module = MODULE_NAME_INTEROPERABILITY,
         name = EVENT_NAME_CCM_PROCESSED,
-        data = {"ccmID": ccmID, "result": CCM_PROCESSED_RESULT_FORWARDED, "code": CCM_PROCESSED_CODE_SUCCESS},
+        data = {"ccm": ccm, "result": CCM_PROCESSED_RESULT_FORWARDED, "code": CCM_PROCESSED_CODE_SUCCESS},
         topics = [ccm.sendingChainID, ccm.receivingChainID]
     )
 ```
@@ -461,8 +464,9 @@ A channel terminated message is created by the Interoperability module when [ter
 
 ```python
 def execute(ccu: Transaction, ccm: CCM) -> None:
-    if isLive(ccm.sendingChainID):
-        createTerminatedStateAccount(ccm.sendingChainID)
+    if terminatedStateAccount(ccm.sendingChainID) exists:
+        return
+    createTerminatedStateAccount(ccm.sendingChainID)
 ```
 
 The function `createTerminatedStateAccount` is defined in [LIP 0045][lip-0045#createTerminatedStateAccount].
@@ -485,23 +489,32 @@ registrationCCMParamsSchema = {
     "type": "object",
     "required" : [
         "name",
+        "chainID",
         "messageFeeTokenID"
     ],
     "properties": {
         "name": {
             "dataType": "string",
+            "minLength": MIN_CHAIN_NAME_LENGTH,
+            "maxLength": MAX_CHAIN_NAME_LENGTH,
             "fieldNumber": 1
         },
+        "chainID": {
+            "dataType": "bytes",
+            "length": CHAIN_ID_LENGTH,
+            "fieldNumber": 2
+        },
         "messageFeeTokenID": {
             "dataType": "bytes",
             "length": TOKEN_ID_LENGTH,
-            "fieldNumber": 2
+            "fieldNumber": 3
         }
     }
 }
 ```
 
 * `name`: name registered on the mainchain.
+* `chainID`: chain ID registered on the mainchain.
 * `messageFeeTokenID`: ID of the token used for cross-chain message fees.
 
 ##### Creation
@@ -512,6 +525,15 @@ A registration message is created by the Interoperability module when registerin
 
 ```python
 def verify(ccu: Transaction, ccm: CCM) -> None:
+    if chainAccount(ccm.sendingChainID) does not exist:
+        raise Exception("Registration message must be sent from a registered chain.")
+
+    if ccm.sendingChainID != ccu.sendingChainID:
+            raise Exception("Registration message must be sent from a direct channel.")
+
+    if chainAccount(ccm.sendingChainID).status != CHAIN_REGISTERED:
+        raise Exception("Registration message must be sent from a chain with status 'registered'.")
+
     if channel(ccm.sendingChainID).inbox.size != 0:
         raise Exception("Registration message must be the first message in the inbox.")
 
@@ -520,6 +542,9 @@ def verify(ccu: Transaction, ccm: CCM) -> None:
 
     if ownChainAccount.chainID != ccm.receivingChainID:
         raise Exception("Registration message must be sent to the chain account ID of the chain.")
+
+    if ownChainAccount.chainID != ccm.params.chainID:
+        raise Exception("Registration message must contain the chain ID of the receiving chain.")
 
     if ownChainAccount.name != ccm.params.name:
         raise Exception("Registration message must contain the name of the registered chain.")
@@ -531,10 +556,6 @@ def verify(ccu: Transaction, ccm: CCM) -> None:
     if ownChainAccount.chainID == CHAIN_ID_MAINCHAIN:
         if ccm.nonce != 0:
             raise Exception("Registration message must have nonce 0.")
-    # Processing on a sidechain.
-    else:
-        if ccm.sendingChainID != CHAIN_ID_MAINCHAIN:
-            raise Exception("Registration message must be sent from the mainchain.")
 ```
 
 ##### Execution
@@ -607,7 +628,13 @@ def verify(ccu: Transaction, ccm: CCM) -> None:
 
 ```python
 def execute(ccu: Transaction, ccm: CCM) -> None:
-    if isLive(ccm.params.chainID):
+    if terminatedStateAccount(ccm.chainID) exists:
+        if terminatedStateAccount(ccm.chainID).initialized == True:
+            return
+        terminatedStateAccount(trs.params.chainID).stateRoot = ccm.params.stateRoot
+        terminatedStateAccount(trs.params.chainID).mainchainStateRoot = EMPTY_HASH
+        terminatedStateAccount(trs.params.chainID).initialized = True
+    else:
         createTerminatedStateAccount(ccm.params.chainID, ccm.params.stateRoot)
 ```