Flexible Port Binding for Transfer Module (#6011)

* remove port check and move portID into genesis state

* move GenesisState to types and implement ExportGenesis

* fix build

* store bound portID in transfer state

* Update x/ibc/20-transfer/types/codec.go

Co-authored-by: Christopher Goes <cwgoes@pluranimity.org>
Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

x/ibc/20-transfer/genesis.go

@@ -7,23 +7,11 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/ibc/20-transfer/types"
 )
 
-// GenesisState is currently only used to ensure that the InitGenesis gets run
-// by the module manager
-type GenesisState struct {
-	Version string `json:"version,omitempty" yaml:"version,omitempty"`
-}
-
-func DefaultGenesis() GenesisState {
-	return GenesisState{
-		Version: types.Version,
-	}
-}
-
-// InitGenesis sets distribution information for genesis
-func InitGenesis(ctx sdk.Context, keeper Keeper) {
+// InitGenesis binds to portid from genesis state
+func InitGenesis(ctx sdk.Context, keeper Keeper, state types.GenesisState) {
 	// transfer module binds to the transfer port on InitChain
 	// and claims the returned capability
-	err := keeper.BindPort(ctx, types.PortID)
+	err := keeper.BindPort(ctx, state.PortID)
 	if err != nil {
 		panic(fmt.Sprintf("could not claim port capability: %v", err))
 	}
@@ -33,3 +21,12 @@ func InitGenesis(ctx sdk.Context, keeper Keeper) {
 		panic(fmt.Sprintf("%s module account has not been set", types.GetModuleAccountName()))
 	}
 }
+
+// ExportGenesis exports transfer module's portID into its geneis state
+func ExportGenesis(ctx sdk.Context, keeper Keeper) types.GenesisState {
+	portID := keeper.GetPort(ctx)
+
+	return types.GenesisState{
+		PortID: portID,
+	}
+}

x/ibc/20-transfer/keeper/keeper.go

@@ -93,10 +93,20 @@ func (k Keeper) ChanCloseInit(ctx sdk.Context, portID, channelID string) error {
 // BindPort defines a wrapper function for the ort Keeper's function in
 // order to expose it to module's InitGenesis function
 func (k Keeper) BindPort(ctx sdk.Context, portID string) error {
+	// Set the portID into our store so we can retrieve it later
+	store := ctx.KVStore(k.storeKey)
+	store.Set([]byte(types.PortKey), []byte(portID))
+
 	cap := k.portKeeper.BindPort(ctx, portID)
 	return k.ClaimCapability(ctx, cap, porttypes.PortPath(portID))
 }
 
+// GetPort returns the portID for the transfer module. Used in ExportGenesis
+func (k Keeper) GetPort(ctx sdk.Context) string {
+	store := ctx.KVStore(k.storeKey)
+	return string(store.Get([]byte(types.PortKey)))
+}
+
 // ClaimCapability allows the transfer module that can claim a capability that IBC module
 // passes to it
 func (k Keeper) ClaimCapability(ctx sdk.Context, cap *capability.Capability, name string) error {

x/ibc/20-transfer/module.go

@@ -48,7 +48,7 @@ func (AppModuleBasic) RegisterCodec(cdc *codec.Codec) {
 // DefaultGenesis returns default genesis state as raw bytes for the ibc
 // transfer module.
 func (AppModuleBasic) DefaultGenesis(cdc codec.JSONMarshaler) json.RawMessage {
-	return cdc.MustMarshalJSON(DefaultGenesis())
+	return cdc.MustMarshalJSON(types.DefaultGenesis())
 }
 
 // ValidateGenesis performs genesis state validation for the ibc transfer module.
@@ -111,14 +111,18 @@ func (am AppModule) NewQuerierHandler() sdk.Querier {
 
 // InitGenesis performs genesis initialization for the ibc transfer module. It returns
 // no validator updates.
-func (am AppModule) InitGenesis(ctx sdk.Context, _ codec.JSONMarshaler, _ json.RawMessage) []abci.ValidatorUpdate {
+func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONMarshaler, data json.RawMessage) []abci.ValidatorUpdate {
+	var genesisState types.GenesisState
+	cdc.MustUnmarshalJSON(data, &genesisState)
+
 	// check if the IBC transfer module account is set
-	InitGenesis(ctx, am.keeper)
+	InitGenesis(ctx, am.keeper, genesisState)
 	return []abci.ValidatorUpdate{}
 }
 
-func (am AppModule) ExportGenesis(ctx sdk.Context, _ codec.JSONMarshaler) json.RawMessage {
-	return nil
+func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONMarshaler) json.RawMessage {
+	gs := ExportGenesis(ctx, am.keeper)
+	return cdc.MustMarshalJSON(gs)
 }
 
 // BeginBlock implements the AppModule interface
@@ -144,8 +148,10 @@ func (am AppModule) OnChanOpenInit(
 ) error {
 	// TODO: Enforce ordering, currently relayers use ORDERED channels
 
-	if counterparty.PortID != types.PortID {
-		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "counterparty has invalid portid. expected: %s, got %s", types.PortID, counterparty.PortID)
+	// Require portID is the portID transfer module is bound to
+	boundPort := am.keeper.GetPort(ctx)
+	if boundPort != portID {
+		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "invalid port: %s, expected %s", portID, boundPort)
 	}
 
 	if version != types.Version {
@@ -174,8 +180,10 @@ func (am AppModule) OnChanOpenTry(
 ) error {
 	// TODO: Enforce ordering, currently relayers use ORDERED channels
 
-	if counterparty.PortID != types.PortID {
-		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "counterparty has invalid portid. expected: %s, got %s", types.PortID, counterparty.PortID)
+	// Require portID is the portID transfer module is bound to
+	boundPort := am.keeper.GetPort(ctx)
+	if boundPort != portID {
+		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "invalid port: %s, expected %s", portID, boundPort)
 	}
 
 	if version != types.Version {

x/ibc/20-transfer/types/genesis.go

@@ -0,0 +1,13 @@
+package types
+
+// GenesisState is currently only used to ensure that the InitGenesis gets run
+// by the module manager
+type GenesisState struct {
+	PortID string `json:"portid" yaml:"portid"`
+}
+
+func DefaultGenesis() GenesisState {
+	return GenesisState{
+		PortID: PortID,
+	}
+}

x/ibc/20-transfer/types/keys.go

@@ -17,7 +17,7 @@ const (
 	// module supports
 	Version = "ics20-1"
 
-	// PortID that transfer module binds to
+	// Default PortID that transfer module binds to
 	PortID = "transfer"
 
 	// StoreKey is the store key string for IBC transfer
@@ -26,6 +26,9 @@ const (
 	// RouterKey is the message route for IBC transfer
 	RouterKey = ModuleName
 
+	// Key to store portID in our store
+	PortKey = "portID"
+
 	// QuerierRoute is the querier route for IBC transfer
 	QuerierRoute = ModuleName
 )