/
server.go
997 lines (878 loc) · 20.2 KB
/
server.go
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// Copyright 2018 The etcd Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package proxy
import (
"fmt"
"io"
mrand "math/rand"
"net"
"net/http"
"net/url"
"strconv"
"strings"
"sync"
"time"
"go.etcd.io/etcd/pkg/transport"
humanize "github.com/dustin/go-humanize"
"go.uber.org/zap"
)
var (
defaultDialTimeout = 3 * time.Second
defaultBufferSize = 48 * 1024
defaultRetryInterval = 10 * time.Millisecond
defaultLogger *zap.Logger
)
func init() {
var err error
defaultLogger, err = zap.NewProduction()
if err != nil {
panic(err)
}
}
// Server defines proxy server layer that simulates common network faults:
// latency spikes and packet drop or corruption. The proxy overhead is very
// small overhead (<500μs per request). Please run tests to compute actual
// overhead.
type Server interface {
// From returns proxy source address in "scheme://host:port" format.
From() string
// To returns proxy destination address in "scheme://host:port" format.
To() string
// Ready returns when proxy is ready to serve.
Ready() <-chan struct{}
// Done returns when proxy has been closed.
Done() <-chan struct{}
// Error sends errors while serving proxy.
Error() <-chan error
// Close closes listener and transport.
Close() error
// PauseAccept stops accepting new connections.
PauseAccept()
// UnpauseAccept removes pause operation on accepting new connections.
UnpauseAccept()
// DelayAccept adds latency ± random variable to accepting
// new incoming connections.
DelayAccept(latency, rv time.Duration)
// UndelayAccept removes sending latencies.
UndelayAccept()
// LatencyAccept returns current latency on accepting
// new incoming connections.
LatencyAccept() time.Duration
// DelayTx adds latency ± random variable for "outgoing" traffic
// in "sending" layer.
DelayTx(latency, rv time.Duration)
// UndelayTx removes sending latencies.
UndelayTx()
// LatencyTx returns current send latency.
LatencyTx() time.Duration
// DelayRx adds latency ± random variable for "incoming" traffic
// in "receiving" layer.
DelayRx(latency, rv time.Duration)
// UndelayRx removes "receiving" latencies.
UndelayRx()
// LatencyRx returns current receive latency.
LatencyRx() time.Duration
// ModifyTx alters/corrupts/drops "outgoing" packets from the listener
// with the given edit function.
ModifyTx(f func(data []byte) []byte)
// UnmodifyTx removes modify operation on "forwarding".
UnmodifyTx()
// ModifyRx alters/corrupts/drops "incoming" packets to client
// with the given edit function.
ModifyRx(f func(data []byte) []byte)
// UnmodifyRx removes modify operation on "receiving".
UnmodifyRx()
// BlackholeTx drops all "outgoing" packets before "forwarding".
// "BlackholeTx" operation is a wrapper around "ModifyTx" with
// a function that returns empty bytes.
BlackholeTx()
// UnblackholeTx removes blackhole operation on "sending".
UnblackholeTx()
// BlackholeRx drops all "incoming" packets to client.
// "BlackholeRx" operation is a wrapper around "ModifyRx" with
// a function that returns empty bytes.
BlackholeRx()
// UnblackholeRx removes blackhole operation on "receiving".
UnblackholeRx()
// PauseTx stops "forwarding" packets; "outgoing" traffic blocks.
PauseTx()
// UnpauseTx removes "forwarding" pause operation.
UnpauseTx()
// PauseRx stops "receiving" packets; "incoming" traffic blocks.
PauseRx()
// UnpauseRx removes "receiving" pause operation.
UnpauseRx()
// ResetListener closes and restarts listener.
ResetListener() error
}
// ServerConfig defines proxy server configuration.
type ServerConfig struct {
Logger *zap.Logger
From url.URL
To url.URL
TLSInfo transport.TLSInfo
DialTimeout time.Duration
BufferSize int
RetryInterval time.Duration
}
type server struct {
lg *zap.Logger
from url.URL
fromPort int
to url.URL
toPort int
tlsInfo transport.TLSInfo
dialTimeout time.Duration
bufferSize int
retryInterval time.Duration
readyc chan struct{}
donec chan struct{}
errc chan error
closeOnce sync.Once
closeWg sync.WaitGroup
listenerMu sync.RWMutex
listener net.Listener
pauseAcceptMu sync.Mutex
pauseAcceptc chan struct{}
latencyAcceptMu sync.RWMutex
latencyAccept time.Duration
modifyTxMu sync.RWMutex
modifyTx func(data []byte) []byte
modifyRxMu sync.RWMutex
modifyRx func(data []byte) []byte
pauseTxMu sync.Mutex
pauseTxc chan struct{}
pauseRxMu sync.Mutex
pauseRxc chan struct{}
latencyTxMu sync.RWMutex
latencyTx time.Duration
latencyRxMu sync.RWMutex
latencyRx time.Duration
}
// NewServer returns a proxy implementation with no iptables/tc dependencies.
// The proxy layer overhead is <1ms.
func NewServer(cfg ServerConfig) Server {
s := &server{
lg: cfg.Logger,
from: cfg.From,
to: cfg.To,
tlsInfo: cfg.TLSInfo,
dialTimeout: cfg.DialTimeout,
bufferSize: cfg.BufferSize,
retryInterval: cfg.RetryInterval,
readyc: make(chan struct{}),
donec: make(chan struct{}),
errc: make(chan error, 16),
pauseAcceptc: make(chan struct{}),
pauseTxc: make(chan struct{}),
pauseRxc: make(chan struct{}),
}
_, fromPort, err := net.SplitHostPort(cfg.From.Host)
if err == nil {
s.fromPort, _ = strconv.Atoi(fromPort)
}
var toPort string
_, toPort, err = net.SplitHostPort(cfg.To.Host)
if err == nil {
s.toPort, _ = strconv.Atoi(toPort)
}
if s.dialTimeout == 0 {
s.dialTimeout = defaultDialTimeout
}
if s.bufferSize == 0 {
s.bufferSize = defaultBufferSize
}
if s.retryInterval == 0 {
s.retryInterval = defaultRetryInterval
}
if s.lg == nil {
s.lg = defaultLogger
}
close(s.pauseAcceptc)
close(s.pauseTxc)
close(s.pauseRxc)
if strings.HasPrefix(s.from.Scheme, "http") {
s.from.Scheme = "tcp"
}
if strings.HasPrefix(s.to.Scheme, "http") {
s.to.Scheme = "tcp"
}
addr := fmt.Sprintf(":%d", s.fromPort)
if s.fromPort == 0 { // unix
addr = s.from.Host
}
var ln net.Listener
if !s.tlsInfo.Empty() {
ln, err = transport.NewListener(addr, s.from.Scheme, &s.tlsInfo)
} else {
ln, err = net.Listen(s.from.Scheme, addr)
}
if err != nil {
s.errc <- err
s.Close()
return s
}
s.listener = ln
s.closeWg.Add(1)
go s.listenAndServe()
s.lg.Info("started proxying", zap.String("from", s.From()), zap.String("to", s.To()))
return s
}
func (s *server) From() string {
return fmt.Sprintf("%s://%s", s.from.Scheme, s.from.Host)
}
func (s *server) To() string {
return fmt.Sprintf("%s://%s", s.to.Scheme, s.to.Host)
}
// TODO: implement packet reordering from multiple TCP connections
// buffer packets per connection for awhile, reorder before transmit
// - https://github.com/etcd-io/etcd/issues/5614
// - https://github.com/etcd-io/etcd/pull/6918#issuecomment-264093034
func (s *server) listenAndServe() {
defer s.closeWg.Done()
s.lg.Info("proxy is listening on", zap.String("from", s.From()))
close(s.readyc)
for {
s.pauseAcceptMu.Lock()
pausec := s.pauseAcceptc
s.pauseAcceptMu.Unlock()
select {
case <-pausec:
case <-s.donec:
return
}
s.latencyAcceptMu.RLock()
lat := s.latencyAccept
s.latencyAcceptMu.RUnlock()
if lat > 0 {
select {
case <-time.After(lat):
case <-s.donec:
return
}
}
s.listenerMu.RLock()
ln := s.listener
s.listenerMu.RUnlock()
in, err := ln.Accept()
if err != nil {
select {
case s.errc <- err:
select {
case <-s.donec:
return
default:
}
case <-s.donec:
return
}
s.lg.Debug("listener accept error", zap.Error(err))
if strings.HasSuffix(err.Error(), "use of closed network connection") {
select {
case <-time.After(s.retryInterval):
case <-s.donec:
return
}
s.lg.Debug("listener is closed; retry listening on", zap.String("from", s.From()))
if err = s.ResetListener(); err != nil {
select {
case s.errc <- err:
select {
case <-s.donec:
return
default:
}
case <-s.donec:
return
}
s.lg.Warn("failed to reset listener", zap.Error(err))
}
}
continue
}
var out net.Conn
if !s.tlsInfo.Empty() {
var tp *http.Transport
tp, err = transport.NewTransport(s.tlsInfo, s.dialTimeout)
if err != nil {
select {
case s.errc <- err:
select {
case <-s.donec:
return
default:
}
case <-s.donec:
return
}
continue
}
out, err = tp.Dial(s.to.Scheme, s.to.Host)
} else {
out, err = net.Dial(s.to.Scheme, s.to.Host)
}
if err != nil {
select {
case s.errc <- err:
select {
case <-s.donec:
return
default:
}
case <-s.donec:
return
}
s.lg.Debug("failed to dial", zap.Error(err))
continue
}
go func() {
// read incoming bytes from listener, dispatch to outgoing connection
s.transmit(out, in)
out.Close()
in.Close()
}()
go func() {
// read response from outgoing connection, write back to listener
s.receive(in, out)
in.Close()
out.Close()
}()
}
}
func (s *server) transmit(dst io.Writer, src io.Reader) {
s.ioCopy(dst, src, proxyTx)
}
func (s *server) receive(dst io.Writer, src io.Reader) {
s.ioCopy(dst, src, proxyRx)
}
type proxyType uint8
const (
proxyTx proxyType = iota
proxyRx
)
func (s *server) ioCopy(dst io.Writer, src io.Reader, ptype proxyType) {
buf := make([]byte, s.bufferSize)
for {
nr1, err := src.Read(buf)
if err != nil {
if err == io.EOF {
return
}
// connection already closed
if strings.HasSuffix(err.Error(), "read: connection reset by peer") {
return
}
if strings.HasSuffix(err.Error(), "use of closed network connection") {
return
}
select {
case s.errc <- err:
select {
case <-s.donec:
return
default:
}
case <-s.donec:
return
}
s.lg.Debug("failed to read", zap.Error(err))
return
}
if nr1 == 0 {
return
}
data := buf[:nr1]
// alters/corrupts/drops data
switch ptype {
case proxyTx:
s.modifyTxMu.RLock()
if s.modifyTx != nil {
data = s.modifyTx(data)
}
s.modifyTxMu.RUnlock()
case proxyRx:
s.modifyRxMu.RLock()
if s.modifyRx != nil {
data = s.modifyRx(data)
}
s.modifyRxMu.RUnlock()
default:
panic("unknown proxy type")
}
nr2 := len(data)
switch ptype {
case proxyTx:
s.lg.Debug(
"modified tx",
zap.String("data-received", humanize.Bytes(uint64(nr1))),
zap.String("data-modified", humanize.Bytes(uint64(nr2))),
zap.String("from", s.From()),
zap.String("to", s.To()),
)
case proxyRx:
s.lg.Debug(
"modified rx",
zap.String("data-received", humanize.Bytes(uint64(nr1))),
zap.String("data-modified", humanize.Bytes(uint64(nr2))),
zap.String("from", s.To()),
zap.String("to", s.From()),
)
default:
panic("unknown proxy type")
}
// pause before packet dropping, blocking, and forwarding
var pausec chan struct{}
switch ptype {
case proxyTx:
s.pauseTxMu.Lock()
pausec = s.pauseTxc
s.pauseTxMu.Unlock()
case proxyRx:
s.pauseRxMu.Lock()
pausec = s.pauseRxc
s.pauseRxMu.Unlock()
default:
panic("unknown proxy type")
}
select {
case <-pausec:
case <-s.donec:
return
}
// pause first, and then drop packets
if nr2 == 0 {
continue
}
// block before forwarding
var lat time.Duration
switch ptype {
case proxyTx:
s.latencyTxMu.RLock()
lat = s.latencyTx
s.latencyTxMu.RUnlock()
case proxyRx:
s.latencyRxMu.RLock()
lat = s.latencyRx
s.latencyRxMu.RUnlock()
default:
panic("unknown proxy type")
}
if lat > 0 {
select {
case <-time.After(lat):
case <-s.donec:
return
}
}
// now forward packets to target
var nw int
nw, err = dst.Write(data)
if err != nil {
if err == io.EOF {
return
}
select {
case s.errc <- err:
select {
case <-s.donec:
return
default:
}
case <-s.donec:
return
}
switch ptype {
case proxyTx:
s.lg.Debug("write fail on tx", zap.Error(err))
case proxyRx:
s.lg.Debug("write fail on rx", zap.Error(err))
default:
panic("unknown proxy type")
}
return
}
if nr2 != nw {
select {
case s.errc <- io.ErrShortWrite:
select {
case <-s.donec:
return
default:
}
case <-s.donec:
return
}
switch ptype {
case proxyTx:
s.lg.Debug(
"write fail on tx; read/write bytes are different",
zap.Int("read-bytes", nr1),
zap.Int("write-bytes", nw),
zap.Error(io.ErrShortWrite),
)
case proxyRx:
s.lg.Debug(
"write fail on rx; read/write bytes are different",
zap.Int("read-bytes", nr1),
zap.Int("write-bytes", nw),
zap.Error(io.ErrShortWrite),
)
default:
panic("unknown proxy type")
}
return
}
switch ptype {
case proxyTx:
s.lg.Debug(
"transmitted",
zap.String("data-size", humanize.Bytes(uint64(nr1))),
zap.String("from", s.From()),
zap.String("to", s.To()),
)
case proxyRx:
s.lg.Debug(
"received",
zap.String("data-size", humanize.Bytes(uint64(nr1))),
zap.String("from", s.To()),
zap.String("to", s.From()),
)
default:
panic("unknown proxy type")
}
}
}
func (s *server) Ready() <-chan struct{} { return s.readyc }
func (s *server) Done() <-chan struct{} { return s.donec }
func (s *server) Error() <-chan error { return s.errc }
func (s *server) Close() (err error) {
s.closeOnce.Do(func() {
close(s.donec)
s.listenerMu.Lock()
if s.listener != nil {
err = s.listener.Close()
s.lg.Info(
"closed proxy listener",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
s.lg.Sync()
s.listenerMu.Unlock()
})
s.closeWg.Wait()
return err
}
func (s *server) PauseAccept() {
s.pauseAcceptMu.Lock()
s.pauseAcceptc = make(chan struct{})
s.pauseAcceptMu.Unlock()
s.lg.Info(
"paused accept",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) UnpauseAccept() {
s.pauseAcceptMu.Lock()
select {
case <-s.pauseAcceptc: // already unpaused
case <-s.donec:
s.pauseAcceptMu.Unlock()
return
default:
close(s.pauseAcceptc)
}
s.pauseAcceptMu.Unlock()
s.lg.Info(
"unpaused accept",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) DelayAccept(latency, rv time.Duration) {
if latency <= 0 {
return
}
d := computeLatency(latency, rv)
s.latencyAcceptMu.Lock()
s.latencyAccept = d
s.latencyAcceptMu.Unlock()
s.lg.Info(
"set accept latency",
zap.Duration("latency", d),
zap.Duration("given-latency", latency),
zap.Duration("given-latency-random-variable", rv),
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) UndelayAccept() {
s.latencyAcceptMu.Lock()
d := s.latencyAccept
s.latencyAccept = 0
s.latencyAcceptMu.Unlock()
s.lg.Info(
"removed accept latency",
zap.Duration("latency", d),
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) LatencyAccept() time.Duration {
s.latencyAcceptMu.RLock()
d := s.latencyAccept
s.latencyAcceptMu.RUnlock()
return d
}
func (s *server) DelayTx(latency, rv time.Duration) {
if latency <= 0 {
return
}
d := computeLatency(latency, rv)
s.latencyTxMu.Lock()
s.latencyTx = d
s.latencyTxMu.Unlock()
s.lg.Info(
"set transmit latency",
zap.Duration("latency", d),
zap.Duration("given-latency", latency),
zap.Duration("given-latency-random-variable", rv),
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) UndelayTx() {
s.latencyTxMu.Lock()
d := s.latencyTx
s.latencyTx = 0
s.latencyTxMu.Unlock()
s.lg.Info(
"removed transmit latency",
zap.Duration("latency", d),
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) LatencyTx() time.Duration {
s.latencyTxMu.RLock()
d := s.latencyTx
s.latencyTxMu.RUnlock()
return d
}
func (s *server) DelayRx(latency, rv time.Duration) {
if latency <= 0 {
return
}
d := computeLatency(latency, rv)
s.latencyRxMu.Lock()
s.latencyRx = d
s.latencyRxMu.Unlock()
s.lg.Info(
"set receive latency",
zap.Duration("latency", d),
zap.Duration("given-latency", latency),
zap.Duration("given-latency-random-variable", rv),
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) UndelayRx() {
s.latencyRxMu.Lock()
d := s.latencyRx
s.latencyRx = 0
s.latencyRxMu.Unlock()
s.lg.Info(
"removed receive latency",
zap.Duration("latency", d),
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) LatencyRx() time.Duration {
s.latencyRxMu.RLock()
d := s.latencyRx
s.latencyRxMu.RUnlock()
return d
}
func computeLatency(lat, rv time.Duration) time.Duration {
if rv == 0 {
return lat
}
if rv < 0 {
rv *= -1
}
if rv > lat {
rv = lat / 10
}
now := time.Now()
mrand.Seed(int64(now.Nanosecond()))
sign := 1
if now.Second()%2 == 0 {
sign = -1
}
return lat + time.Duration(int64(sign)*mrand.Int63n(rv.Nanoseconds()))
}
func (s *server) ModifyTx(f func([]byte) []byte) {
s.modifyTxMu.Lock()
s.modifyTx = f
s.modifyTxMu.Unlock()
s.lg.Info(
"modifying tx",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) UnmodifyTx() {
s.modifyTxMu.Lock()
s.modifyTx = nil
s.modifyTxMu.Unlock()
s.lg.Info(
"unmodifyed tx",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) ModifyRx(f func([]byte) []byte) {
s.modifyRxMu.Lock()
s.modifyRx = f
s.modifyRxMu.Unlock()
s.lg.Info(
"modifying rx",
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) UnmodifyRx() {
s.modifyRxMu.Lock()
s.modifyRx = nil
s.modifyRxMu.Unlock()
s.lg.Info(
"unmodifyed rx",
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) BlackholeTx() {
s.ModifyTx(func([]byte) []byte { return nil })
s.lg.Info(
"blackholed tx",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) UnblackholeTx() {
s.UnmodifyTx()
s.lg.Info(
"unblackholed tx",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) BlackholeRx() {
s.ModifyRx(func([]byte) []byte { return nil })
s.lg.Info(
"blackholed rx",
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) UnblackholeRx() {
s.UnmodifyRx()
s.lg.Info(
"unblackholed rx",
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) PauseTx() {
s.pauseTxMu.Lock()
s.pauseTxc = make(chan struct{})
s.pauseTxMu.Unlock()
s.lg.Info(
"paused tx",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) UnpauseTx() {
s.pauseTxMu.Lock()
select {
case <-s.pauseTxc: // already unpaused
case <-s.donec:
s.pauseTxMu.Unlock()
return
default:
close(s.pauseTxc)
}
s.pauseTxMu.Unlock()
s.lg.Info(
"unpaused tx",
zap.String("from", s.From()),
zap.String("to", s.To()),
)
}
func (s *server) PauseRx() {
s.pauseRxMu.Lock()
s.pauseRxc = make(chan struct{})
s.pauseRxMu.Unlock()
s.lg.Info(
"paused rx",
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) UnpauseRx() {
s.pauseRxMu.Lock()
select {
case <-s.pauseRxc: // already unpaused
case <-s.donec:
s.pauseRxMu.Unlock()
return
default:
close(s.pauseRxc)
}
s.pauseRxMu.Unlock()
s.lg.Info(
"unpaused rx",
zap.String("from", s.To()),
zap.String("to", s.From()),
)
}
func (s *server) ResetListener() error {
s.listenerMu.Lock()
defer s.listenerMu.Unlock()
if err := s.listener.Close(); err != nil {
// already closed
if !strings.HasSuffix(err.Error(), "use of closed network connection") {
return err
}
}
var ln net.Listener
var err error
if !s.tlsInfo.Empty() {
ln, err = transport.NewListener(s.from.Host, s.from.Scheme, &s.tlsInfo)
} else {
ln, err = net.Listen(s.from.Scheme, s.from.Host)
}
if err != nil {
return err
}
s.listener = ln
s.lg.Info(
"reset listener on",
zap.String("from", s.From()),
)
return nil
}