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package privval
import (
"fmt"
"io"
"net"
"github.com/pkg/errors"
"github.com/tendermint/go-amino"
"github.com/tendermint/tendermint/crypto"
cmn "github.com/tendermint/tendermint/libs/common"
"github.com/tendermint/tendermint/types"
)
// Socket errors.
var (
ErrConnTimeout = errors.New("remote signer timed out")
)
// RemoteSignerClient implements PrivValidator.
// It uses a net.Conn to request signatures
// from an external process.
type RemoteSignerClient struct {
conn net.Conn
// memoized
consensusPubKey crypto.PubKey
}
// Check that RemoteSignerClient implements PrivValidator.
var _ types.PrivValidator = (*RemoteSignerClient)(nil)
// NewRemoteSignerClient returns an instance of RemoteSignerClient.
func NewRemoteSignerClient(conn net.Conn) (*RemoteSignerClient, error) {
// retrieve and memoize the consensus public key once.
pubKey, err := getPubKey(conn)
if err != nil {
return nil, cmn.ErrorWrap(err, "error while retrieving public key for remote signer")
}
return &RemoteSignerClient{
conn: conn,
consensusPubKey: pubKey,
}, nil
}
// Close calls Close on the underlying net.Conn.
func (sc *RemoteSignerClient) Close() error {
return sc.conn.Close()
}
// GetPubKey implements PrivValidator.
func (sc *RemoteSignerClient) GetPubKey() crypto.PubKey {
return sc.consensusPubKey
}
// not thread-safe (only called on startup).
func getPubKey(conn net.Conn) (crypto.PubKey, error) {
err := writeMsg(conn, &PubKeyRequest{})
if err != nil {
return nil, err
}
res, err := readMsg(conn)
if err != nil {
return nil, err
}
pubKeyResp, ok := res.(*PubKeyResponse)
if !ok {
return nil, errors.Wrap(ErrUnexpectedResponse, "response is not PubKeyResponse")
}
if pubKeyResp.Error != nil {
return nil, errors.Wrap(pubKeyResp.Error, "failed to get private validator's public key")
}
return pubKeyResp.PubKey, nil
}
// SignVote implements PrivValidator.
func (sc *RemoteSignerClient) SignVote(chainID string, vote *types.Vote) error {
err := writeMsg(sc.conn, &SignVoteRequest{Vote: vote})
if err != nil {
return err
}
res, err := readMsg(sc.conn)
if err != nil {
return err
}
resp, ok := res.(*SignedVoteResponse)
if !ok {
return ErrUnexpectedResponse
}
if resp.Error != nil {
return resp.Error
}
*vote = *resp.Vote
return nil
}
// SignProposal implements PrivValidator.
func (sc *RemoteSignerClient) SignProposal(
chainID string,
proposal *types.Proposal,
) error {
err := writeMsg(sc.conn, &SignProposalRequest{Proposal: proposal})
if err != nil {
return err
}
res, err := readMsg(sc.conn)
if err != nil {
return err
}
resp, ok := res.(*SignedProposalResponse)
if !ok {
return ErrUnexpectedResponse
}
if resp.Error != nil {
return resp.Error
}
*proposal = *resp.Proposal
return nil
}
// Ping is used to check connection health.
func (sc *RemoteSignerClient) Ping() error {
err := writeMsg(sc.conn, &PingRequest{})
if err != nil {
return err
}
res, err := readMsg(sc.conn)
if err != nil {
return err
}
_, ok := res.(*PingResponse)
if !ok {
return ErrUnexpectedResponse
}
return nil
}
// RemoteSignerMsg is sent between RemoteSigner and the RemoteSigner client.
type RemoteSignerMsg interface{}
func RegisterRemoteSignerMsg(cdc *amino.Codec) {
cdc.RegisterInterface((*RemoteSignerMsg)(nil), nil)
cdc.RegisterConcrete(&PubKeyRequest{}, "tendermint/remotesigner/PubKeyRequest", nil)
cdc.RegisterConcrete(&PubKeyResponse{}, "tendermint/remotesigner/PubKeyResponse", nil)
cdc.RegisterConcrete(&SignVoteRequest{}, "tendermint/remotesigner/SignVoteRequest", nil)
cdc.RegisterConcrete(&SignedVoteResponse{}, "tendermint/remotesigner/SignedVoteResponse", nil)
cdc.RegisterConcrete(&SignProposalRequest{}, "tendermint/remotesigner/SignProposalRequest", nil)
cdc.RegisterConcrete(&SignedProposalResponse{}, "tendermint/remotesigner/SignedProposalResponse", nil)
cdc.RegisterConcrete(&PingRequest{}, "tendermint/remotesigner/PingRequest", nil)
cdc.RegisterConcrete(&PingResponse{}, "tendermint/remotesigner/PingResponse", nil)
}
// PubKeyRequest requests the consensus public key from the remote signer.
type PubKeyRequest struct{}
// PubKeyResponse is a PrivValidatorSocket message containing the public key.
type PubKeyResponse struct {
PubKey crypto.PubKey
Error *RemoteSignerError
}
// SignVoteRequest is a PrivValidatorSocket message containing a vote.
type SignVoteRequest struct {
Vote *types.Vote
}
// SignedVoteResponse is a PrivValidatorSocket message containing a signed vote along with a potenial error message.
type SignedVoteResponse struct {
Vote *types.Vote
Error *RemoteSignerError
}
// SignProposalRequest is a PrivValidatorSocket message containing a Proposal.
type SignProposalRequest struct {
Proposal *types.Proposal
}
type SignedProposalResponse struct {
Proposal *types.Proposal
Error *RemoteSignerError
}
// PingRequest is a PrivValidatorSocket message to keep the connection alive.
type PingRequest struct {
}
type PingResponse struct {
}
// RemoteSignerError allows (remote) validators to include meaningful error descriptions in their reply.
type RemoteSignerError struct {
// TODO(ismail): create an enum of known errors
Code int
Description string
}
func (e *RemoteSignerError) Error() string {
return fmt.Sprintf("RemoteSigner returned error #%d: %s", e.Code, e.Description)
}
func readMsg(r io.Reader) (msg RemoteSignerMsg, err error) {
const maxRemoteSignerMsgSize = 1024 * 10
_, err = cdc.UnmarshalBinaryLengthPrefixedReader(r, &msg, maxRemoteSignerMsgSize)
if _, ok := err.(timeoutError); ok {
err = cmn.ErrorWrap(ErrConnTimeout, err.Error())
}
return
}
func writeMsg(w io.Writer, msg interface{}) (err error) {
_, err = cdc.MarshalBinaryLengthPrefixedWriter(w, msg)
if _, ok := err.(timeoutError); ok {
err = cmn.ErrorWrap(ErrConnTimeout, err.Error())
}
return
}
func handleRequest(req RemoteSignerMsg, chainID string, privVal types.PrivValidator) (RemoteSignerMsg, error) {
var res RemoteSignerMsg
var err error
switch r := req.(type) {
case *PubKeyRequest:
var p crypto.PubKey
p = privVal.GetPubKey()
res = &PubKeyResponse{p, nil}
case *SignVoteRequest:
err = privVal.SignVote(chainID, r.Vote)
if err != nil {
res = &SignedVoteResponse{nil, &RemoteSignerError{0, err.Error()}}
} else {
res = &SignedVoteResponse{r.Vote, nil}
}
case *SignProposalRequest:
err = privVal.SignProposal(chainID, r.Proposal)
if err != nil {
res = &SignedProposalResponse{nil, &RemoteSignerError{0, err.Error()}}
} else {
res = &SignedProposalResponse{r.Proposal, nil}
}
case *PingRequest:
res = &PingResponse{}
default:
err = fmt.Errorf("unknown msg: %v", r)
}
return res, err
}