infractions.go

package keeper

import (
	"fmt"

	"github.com/cockroachdb/errors"

	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
	sdk "github.com/cosmos/cosmos-sdk/types"
	"github.com/cosmos/cosmos-sdk/x/slashing/types"
	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
)

// HandleValidatorSignature handles a validator signature, must be called once per validator per block.
func (k Keeper) HandleValidatorSignature(ctx sdk.Context, addr cryptotypes.Address, power int64, signed bool) {
	logger := k.Logger(ctx)
	height := ctx.BlockHeight()

	// fetch the validator public key
	consAddr := sdk.ConsAddress(addr)
	if _, err := k.GetPubkey(ctx, addr); err != nil {
		panic(fmt.Sprintf("Validator consensus-address %s not found", consAddr))
	}

	// don't update missed blocks when validator's jailed
	if k.sk.IsValidatorJailed(ctx, consAddr) {
		return
	}

	// fetch signing info
	signInfo, found := k.GetValidatorSigningInfo(ctx, consAddr)
	if !found {
		panic(fmt.Sprintf("Expected signing info for validator %s but not found", consAddr))
	}

	// Compute the relative index, so we count the blocks the validator *should*
	// have signed. We will use the 0-value default signing info if not present,
	// except for start height. The index is in the range [0, SignedBlocksWindow)
	// and is used to see if a validator signed a block at the given height, which
	// is represented by a bit in the bitmap.
	index := signInfo.IndexOffset % k.SignedBlocksWindow(ctx)
	signInfo.IndexOffset++

	// determine if the validator signed the previous block
	previous, err := k.GetMissedBlockBitmapValue(ctx, consAddr, index)
	if err != nil {
		panic(errors.Wrap(err, "failed to get the validator's bitmap value"))
	}

	missed := !signed
	switch {
	case !previous && missed:
		// Bitmap value has changed from not missed to missed, so we flip the bit
		// and increment the counter.
		if err := k.SetMissedBlockBitmapValue(ctx, consAddr, index, true); err != nil {
			panic(err)
		}

		signInfo.MissedBlocksCounter++

	case previous && !missed:
		// Bitmap value has changed from missed to not missed, so we flip the bit
		// and decrement the counter.
		if err := k.SetMissedBlockBitmapValue(ctx, consAddr, index, false); err != nil {
			panic(err)
		}

		signInfo.MissedBlocksCounter--

	default:
		// bitmap value at this index has not changed, no need to update counter
	}

	minSignedPerWindow := k.MinSignedPerWindow(ctx)

	if missed {
		ctx.EventManager().EmitEvent(
			sdk.NewEvent(
				types.EventTypeLiveness,
				sdk.NewAttribute(types.AttributeKeyAddress, consAddr.String()),
				sdk.NewAttribute(types.AttributeKeyMissedBlocks, fmt.Sprintf("%d", signInfo.MissedBlocksCounter)),
				sdk.NewAttribute(types.AttributeKeyHeight, fmt.Sprintf("%d", height)),
			),
		)

		logger.Debug(
			"absent validator",
			"height", height,
			"validator", consAddr.String(),
			"missed", signInfo.MissedBlocksCounter,
			"threshold", minSignedPerWindow,
		)
	}

	minHeight := signInfo.StartHeight + k.SignedBlocksWindow(ctx)
	maxMissed := k.SignedBlocksWindow(ctx) - minSignedPerWindow

	// if we are past the minimum height and the validator has missed too many blocks, punish them
	if height > minHeight && signInfo.MissedBlocksCounter > maxMissed {
		validator := k.sk.ValidatorByConsAddr(ctx, consAddr)
		if validator != nil && !validator.IsJailed() {
			// Downtime confirmed: slash and jail the validator
			// We need to retrieve the stake distribution which signed the block, so we subtract ValidatorUpdateDelay from the evidence height,
			// and subtract an additional 1 since this is the LastCommit.
			// Note that this *can* result in a negative "distributionHeight" up to -ValidatorUpdateDelay-1,
			// i.e. at the end of the pre-genesis block (none) = at the beginning of the genesis block.
			// That's fine since this is just used to filter unbonding delegations & redelegations.
			distributionHeight := height - sdk.ValidatorUpdateDelay - 1

			coinsBurned := k.sk.SlashWithInfractionReason(ctx, consAddr, distributionHeight, power, k.SlashFractionDowntime(ctx), stakingtypes.Infraction_INFRACTION_DOWNTIME)
			ctx.EventManager().EmitEvent(
				sdk.NewEvent(
					types.EventTypeSlash,
					sdk.NewAttribute(types.AttributeKeyAddress, consAddr.String()),
					sdk.NewAttribute(types.AttributeKeyPower, fmt.Sprintf("%d", power)),
					sdk.NewAttribute(types.AttributeKeyReason, types.AttributeValueMissingSignature),
					sdk.NewAttribute(types.AttributeKeyJailed, consAddr.String()),
					sdk.NewAttribute(types.AttributeKeyBurnedCoins, coinsBurned.String()),
				),
			)
			k.sk.Jail(ctx, consAddr)

			signInfo.JailedUntil = ctx.BlockHeader().Time.Add(k.DowntimeJailDuration(ctx))

			// We need to reset the counter & bitmap so that the validator won't be
			// immediately slashed for downtime upon re-bonding.
			signInfo.MissedBlocksCounter = 0
			signInfo.IndexOffset = 0
			k.DeleteMissedBlockBitmap(ctx, consAddr)

			logger.Info(
				"slashing and jailing validator due to liveness fault",
				"height", height,
				"validator", consAddr.String(),
				"min_height", minHeight,
				"threshold", minSignedPerWindow,
				"slashed", k.SlashFractionDowntime(ctx).String(),
				"jailed_until", signInfo.JailedUntil,
			)
		} else {
			// validator was (a) not found or (b) already jailed so we do not slash
			logger.Info(
				"validator would have been slashed for downtime, but was either not found in store or already jailed",
				"validator", consAddr.String(),
			)
		}
	}

	// Set the updated signing info
	k.SetValidatorSigningInfo(ctx, consAddr, signInfo)
}