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Fix and simplify reverts of forwarding state (#6574)
* refactor: initial simplification attempt * refactor: further organize * fix: all tests fixed * docs: improved godocs * fix: logic and testing error * style: self suggestion * docs: suggestion * docs: spellcheck * style: suggestions * style: renamed to revertForwardedPacket * style: suggestion * docs: remove docs * docs: godoc suggestion * style: suggestion * docs: colin suggestions
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,99 @@ | ||
| package keeper | ||
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| import ( | ||
| "errors" | ||
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| errorsmod "cosmossdk.io/errors" | ||
| sdkmath "cosmossdk.io/math" | ||
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| sdk "github.com/cosmos/cosmos-sdk/types" | ||
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| "github.com/cosmos/ibc-go/v8/modules/apps/transfer/types" | ||
| channeltypes "github.com/cosmos/ibc-go/v8/modules/core/04-channel/types" | ||
| host "github.com/cosmos/ibc-go/v8/modules/core/24-host" | ||
| ) | ||
|
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| // ackForwardPacketError reverts the receive packet logic that occurs in the middle chain and writes the async ack for the prevPacket | ||
| func (k Keeper) ackForwardPacketError(ctx sdk.Context, prevPacket channeltypes.Packet, failedPacketData types.FungibleTokenPacketDataV2) error { | ||
| // the forwarded packet has failed, thus the funds have been refunded to the intermediate address. | ||
| // we must revert the changes that came from successfully receiving the tokens on our chain | ||
| // before propagating the error acknowledgement back to original sender chain | ||
| if err := k.revertForwardedPacket(ctx, prevPacket, failedPacketData); err != nil { | ||
| return err | ||
| } | ||
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| forwardAck := channeltypes.NewErrorAcknowledgement(errors.New("forwarded packet failed")) | ||
| return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardAck) | ||
| } | ||
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| // ackForwardPacketSuccess writes a successful async acknowledgement for the prevPacket | ||
| func (k Keeper) ackForwardPacketSuccess(ctx sdk.Context, prevPacket channeltypes.Packet) error { | ||
| forwardAck := channeltypes.NewResultAcknowledgement([]byte("forwarded packet succeeded")) | ||
| return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardAck) | ||
| } | ||
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| // ackForwardPacketTimeout reverts the receive packet logic that occurs in the middle chain and writes a failed async ack for the prevPacket | ||
| func (k Keeper) ackForwardPacketTimeout(ctx sdk.Context, prevPacket channeltypes.Packet, timeoutPacketData types.FungibleTokenPacketDataV2) error { | ||
| if err := k.revertForwardedPacket(ctx, prevPacket, timeoutPacketData); err != nil { | ||
| return err | ||
| } | ||
|
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| // the timeout is converted into an error acknowledgement in order to propagate the failed packet forwarding | ||
| // back to the original sender | ||
| forwardAck := channeltypes.NewErrorAcknowledgement(errors.New("forwarded packet timed out")) | ||
| return k.acknowledgeForwardedPacket(ctx, prevPacket, forwardAck) | ||
| } | ||
|
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| // acknowledgeForwardedPacket writes the async acknowledgement for packet | ||
| func (k Keeper) acknowledgeForwardedPacket(ctx sdk.Context, packet channeltypes.Packet, ack channeltypes.Acknowledgement) error { | ||
| capability, ok := k.scopedKeeper.GetCapability(ctx, host.ChannelCapabilityPath(packet.DestinationPort, packet.DestinationChannel)) | ||
| if !ok { | ||
| return errorsmod.Wrap(channeltypes.ErrChannelCapabilityNotFound, "module does not own channel capability") | ||
| } | ||
|
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| return k.ics4Wrapper.WriteAcknowledgement(ctx, capability, packet, ack) | ||
| } | ||
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| // revertForwardedPacket reverts the logic of receive packet that occurs in the middle chains during a packet forwarding. | ||
| // If the packet fails to be forwarded all the way to the final destination, the state changes on this chain must be reverted | ||
| // before sending back the error acknowledgement to ensure atomic packet forwarding. | ||
| func (k Keeper) revertForwardedPacket(ctx sdk.Context, prevPacket channeltypes.Packet, failedPacketData types.FungibleTokenPacketDataV2) error { | ||
| /* | ||
| Recall that RecvPacket handles an incoming packet depending on the denom of the received funds: | ||
| 1. If the funds are native, then the amount is sent to the receiver from the escrow. | ||
| 2. If the funds are foreign, then a voucher token is minted. | ||
| We revert it in this function by: | ||
| 1. Sending funds back to escrow if the funds are native. | ||
| 2. Burning voucher tokens if the funds are foreign | ||
| */ | ||
|
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| forwardingAddr := types.GetForwardAddress(prevPacket.DestinationPort, prevPacket.DestinationChannel) | ||
| escrow := types.GetEscrowAddress(prevPacket.DestinationPort, prevPacket.DestinationChannel) | ||
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| // we can iterate over the received tokens of prevPacket by iterating over the sent tokens of failedPacketData | ||
| for _, token := range failedPacketData.Tokens { | ||
| // parse the transfer amount | ||
| transferAmount, ok := sdkmath.NewIntFromString(token.Amount) | ||
| if !ok { | ||
| return errorsmod.Wrapf(types.ErrInvalidAmount, "unable to parse transfer amount (%s) into math.Int", transferAmount) | ||
| } | ||
| coin := sdk.NewCoin(token.Denom.IBCDenom(), transferAmount) | ||
|
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| // check if the token we received originated on the sender | ||
| // given that the packet is being reversed, we check the DestinationChannel and DestinationPort | ||
| // of the prevPacket to see if a hop was added to the trace during the receive step | ||
| if token.Denom.SenderChainIsSource(prevPacket.DestinationPort, prevPacket.DestinationChannel) { | ||
| // then send it back to the escrow address | ||
| if err := k.escrowCoin(ctx, forwardingAddr, escrow, coin); err != nil { | ||
| return err | ||
| } | ||
|
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| continue | ||
| } | ||
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| if err := k.burnCoin(ctx, forwardingAddr, coin); err != nil { | ||
| return err | ||
| } | ||
| } | ||
| return nil | ||
| } |
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