100 lines
2.7 KiB
Go
100 lines
2.7 KiB
Go
package lite
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import (
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"bytes"
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"github.com/pkg/errors"
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"github.com/tendermint/tendermint/types"
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liteErr "github.com/tendermint/tendermint/lite/errors"
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)
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// Certifier checks the votes to make sure the block really is signed properly.
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// Certifier must know the current set of validitors by some other means.
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type Certifier interface {
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Certify(check Commit) error
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ChainID() string
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}
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// Commit is basically the rpc /commit response, but extended
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//
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// This is the basepoint for proving anything on the blockchain. It contains
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// a signed header. If the signatures are valid and > 2/3 of the known set,
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// we can store this checkpoint and use it to prove any number of aspects of
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// the system: such as txs, abci state, validator sets, etc...
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type Commit types.SignedHeader
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// FullCommit is a commit and the actual validator set,
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// the base info you need to update to a given point,
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// assuming knowledge of some previous validator set
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type FullCommit struct {
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Commit `json:"commit"`
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Validators *types.ValidatorSet `json:"validator_set"`
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}
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// NewFullCommit returns a new FullCommit.
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func NewFullCommit(commit Commit, vals *types.ValidatorSet) FullCommit {
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return FullCommit{
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Commit: commit,
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Validators: vals,
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}
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}
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// Height returns the height of the header.
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func (c Commit) Height() int64 {
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if c.Header == nil {
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return 0
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}
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return c.Header.Height
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}
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// ValidatorsHash returns the hash of the validator set.
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func (c Commit) ValidatorsHash() []byte {
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if c.Header == nil {
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return nil
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}
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return c.Header.ValidatorsHash
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}
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// ValidateBasic does basic consistency checks and makes sure the headers
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// and commits are all consistent and refer to our chain.
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//
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// Make sure to use a Verifier to validate the signatures actually provide
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// a significantly strong proof for this header's validity.
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func (c Commit) ValidateBasic(chainID string) error {
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// make sure the header is reasonable
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if c.Header == nil {
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return errors.New("Commit missing header")
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}
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if c.Header.ChainID != chainID {
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return errors.Errorf("Header belongs to another chain '%s' not '%s'",
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c.Header.ChainID, chainID)
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}
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if c.Commit == nil {
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return errors.New("Commit missing signatures")
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}
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// make sure the header and commit match (height and hash)
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if c.Commit.Height() != c.Header.Height {
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return liteErr.ErrHeightMismatch(c.Commit.Height(), c.Header.Height)
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}
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hhash := c.Header.Hash()
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chash := c.Commit.BlockID.Hash
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if !bytes.Equal(hhash, chash) {
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return errors.Errorf("Commits sign block %X header is block %X",
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chash, hhash)
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}
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// make sure the commit is reasonable
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err := c.Commit.ValidateBasic()
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if err != nil {
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return errors.WithStack(err)
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}
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// looks good, we just need to make sure the signatures are really from
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// empowered validators
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return nil
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}
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