tendermint/privval/signer_dialer_endpoint.go
Juan Leni f7f034a8be privval: refactor Remote signers (#3370)
This PR is related to #3107 and a continuation of #3351

It is important to emphasise that in the privval original design, client/server and listening/dialing roles are inverted and do not follow a conventional interaction.

Given two hosts A and B:

    Host A is listener/client
    Host B is dialer/server (contains the secret key)
    When A requires a signature, it needs to wait for B to dial in before it can issue a request.
    A only accepts a single connection and any failure leads to dropping the connection and waiting for B to reconnect.

The original rationale behind this design was based on security.

    Host B only allows outbound connections to a list of whitelisted hosts.
    It is not possible to reach B unless B dials in. There are no listening/open ports in B.

This PR results in the following changes:

    Refactors ping/heartbeat to avoid previously existing race conditions.
    Separates transport (dialer/listener) from signing (client/server) concerns to simplify workflow.
    Unifies and abstracts away the differences between unix and tcp sockets.
    A single signer endpoint implementation unifies connection handling code (read/write/close/connection obj)
    The signer request handler (server side) is customizable to increase testability.
    Updates and extends unit tests

A high level overview of the classes is as follows:

Transport (endpoints): The following classes take care of establishing a connection

    SignerDialerEndpoint
    SignerListeningEndpoint
    SignerEndpoint groups common functionality (read/write/timeouts/etc.)

Signing (client/server): The following classes take care of exchanging request/responses

    SignerClient
    SignerServer

This PR also closes #3601

Commits:

* refactoring - work in progress

* reworking unit tests

* Encapsulating and fixing unit tests

* Improve tests

* Clean up

* Fix/improve unit tests

* clean up tests

* Improving service endpoint

* fixing unit test

* fix linter issues

* avoid invalid cache values (improve later?)

* complete implementation

* wip

* improved connection loop

* Improve reconnections + fixing unit tests

* addressing comments

* small formatting changes

* clean up

* Update node/node.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_client.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_client_test.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* check during initialization

* dropping connecting when writing fails

* removing break

* use t.log instead

* unifying and using cmn.GetFreePort()

* review fixes

* reordering and unifying drop connection

* closing instead of signalling

* refactored service loop

* removed superfluous brackets

* GetPubKey can return errors

* Revert "GetPubKey can return errors"

This reverts commit 68c06f19b4650389d7e5ab1659b318889028202c.

* adding entry to changelog

* Update CHANGELOG_PENDING.md

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_client.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_dialer_endpoint.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_dialer_endpoint.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_dialer_endpoint.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_dialer_endpoint.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* Update privval/signer_listener_endpoint_test.go

Co-Authored-By: jleni <juan.leni@zondax.ch>

* updating node.go

* review fixes

* fixes linter

* fixing unit test

* small fixes in comments

* addressing review comments

* addressing review comments 2

* reverting suggestion

* Update privval/signer_client_test.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update privval/signer_client_test.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update privval/signer_listener_endpoint_test.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* do not expose brokenSignerDialerEndpoint

* clean up logging

* unifying methods

shorten test time
signer also drops

* reenabling pings

* improving testability + unit test

* fixing go fmt + unit test

* remove unused code

* Addressing review comments

* simplifying connection workflow

* fix linter/go import issue

* using base service quit

* updating comment

* Simplifying design + adjusting names

* fixing linter issues

* refactoring test harness + fixes

* Addressing review comments

* cleaning up

* adding additional error check
2019-08-05 19:09:10 +04:00

85 lines
2.3 KiB
Go

package privval
import (
"time"
cmn "github.com/tendermint/tendermint/libs/common"
"github.com/tendermint/tendermint/libs/log"
)
const (
defaultMaxDialRetries = 10
defaultRetryWaitMilliseconds = 100
)
// SignerServiceEndpointOption sets an optional parameter on the SignerDialerEndpoint.
type SignerServiceEndpointOption func(*SignerDialerEndpoint)
// SignerDialerEndpointTimeoutReadWrite sets the read and write timeout for connections
// from external signing processes.
func SignerDialerEndpointTimeoutReadWrite(timeout time.Duration) SignerServiceEndpointOption {
return func(ss *SignerDialerEndpoint) { ss.timeoutReadWrite = timeout }
}
// SignerDialerEndpointConnRetries sets the amount of attempted retries to acceptNewConnection.
func SignerDialerEndpointConnRetries(retries int) SignerServiceEndpointOption {
return func(ss *SignerDialerEndpoint) { ss.maxConnRetries = retries }
}
// SignerDialerEndpoint dials using its dialer and responds to any
// signature requests using its privVal.
type SignerDialerEndpoint struct {
signerEndpoint
dialer SocketDialer
retryWait time.Duration
maxConnRetries int
}
// NewSignerDialerEndpoint returns a SignerDialerEndpoint that will dial using the given
// dialer and respond to any signature requests over the connection
// using the given privVal.
func NewSignerDialerEndpoint(
logger log.Logger,
dialer SocketDialer,
) *SignerDialerEndpoint {
sd := &SignerDialerEndpoint{
dialer: dialer,
retryWait: defaultRetryWaitMilliseconds * time.Millisecond,
maxConnRetries: defaultMaxDialRetries,
}
sd.BaseService = *cmn.NewBaseService(logger, "SignerDialerEndpoint", sd)
sd.signerEndpoint.timeoutReadWrite = defaultTimeoutReadWriteSeconds * time.Second
return sd
}
func (sd *SignerDialerEndpoint) ensureConnection() error {
if sd.IsConnected() {
return nil
}
retries := 0
for retries < sd.maxConnRetries {
conn, err := sd.dialer()
if err != nil {
retries++
sd.Logger.Debug("SignerDialer: Reconnection failed", "retries", retries, "max", sd.maxConnRetries, "err", err)
// Wait between retries
time.Sleep(sd.retryWait)
} else {
sd.SetConnection(conn)
sd.Logger.Debug("SignerDialer: Connection Ready")
return nil
}
}
sd.Logger.Debug("SignerDialer: Max retries exceeded", "retries", retries, "max", sd.maxConnRetries)
return ErrNoConnection
}