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minio/cmd/http/server.go

206 lines
6.8 KiB

/*
* Minio Cloud Storage, (C) 2017 Minio, Inc.
*
* 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 http
import (
"crypto/tls"
"errors"
"net/http"
"sync"
"sync/atomic"
"time"
humanize "github.com/dustin/go-humanize"
"github.com/minio/minio-go/pkg/set"
)
const (
serverShutdownPoll = 500 * time.Millisecond
// DefaultShutdownTimeout - default shutdown timeout used for graceful http server shutdown.
DefaultShutdownTimeout = 5 * time.Second
// DefaultTCPKeepAliveTimeout - default TCP keep alive timeout for accepted connection.
DefaultTCPKeepAliveTimeout = 10 * time.Second
// DefaultReadTimeout - default timout to read data from accepted connection.
DefaultReadTimeout = 5 * time.Minute
// DefaultWriteTimeout - default timout to write data to accepted connection.
DefaultWriteTimeout = 5 * time.Minute
// DefaultMaxHeaderBytes - default maximum HTTP header size in bytes.
DefaultMaxHeaderBytes = 1 * humanize.MiByte
)
// Server - extended http.Server supports multiple addresses to serve and enhanced connection handling.
type Server struct {
http.Server
Addrs []string // addresses on which the server listens for new connection.
ShutdownTimeout time.Duration // timeout used for graceful server shutdown.
TCPKeepAliveTimeout time.Duration // timeout used for underneath TCP connection.
UpdateBytesReadFunc func(int) // function to be called to update bytes read in bufConn.
UpdateBytesWrittenFunc func(int) // function to be called to update bytes written in bufConn.
listenerMutex *sync.Mutex // to guard 'listener' field.
listener *httpListener // HTTP listener for all 'Addrs' field.
inShutdown uint32 // indicates whether the server is in shutdown or not
requestCount int32 // counter holds no. of request in process.
}
// Start - start HTTP server
func (srv *Server) Start() (err error) {
// Take a copy of server fields.
var tlsConfig *tls.Config
if srv.TLSConfig != nil {
tlsConfig = srv.TLSConfig.Clone()
}
readTimeout := srv.ReadTimeout
writeTimeout := srv.WriteTimeout
handler := srv.Handler // if srv.Handler holds non-synced state -> possible data race
addrs := set.CreateStringSet(srv.Addrs...).ToSlice() // copy and remove duplicates
tcpKeepAliveTimeout := srv.TCPKeepAliveTimeout
updateBytesReadFunc := srv.UpdateBytesReadFunc
updateBytesWrittenFunc := srv.UpdateBytesWrittenFunc
// Create new HTTP listener.
var listener *httpListener
listener, err = newHTTPListener(
addrs,
tlsConfig,
tcpKeepAliveTimeout,
readTimeout,
writeTimeout,
updateBytesReadFunc,
updateBytesWrittenFunc,
)
if err != nil {
return err
}
// Wrap given handler to do additional
// * return 503 (service unavailable) if the server in shutdown.
wrappedHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
atomic.AddInt32(&srv.requestCount, 1)
defer atomic.AddInt32(&srv.requestCount, -1)
// If server is in shutdown, return 503 (service unavailable)
if atomic.LoadUint32(&srv.inShutdown) != 0 {
w.WriteHeader(http.StatusServiceUnavailable)
return
}
// Handle request using passed handler.
handler.ServeHTTP(w, r)
})
srv.listenerMutex.Lock()
srv.Handler = wrappedHandler
srv.listener = listener
srv.listenerMutex.Unlock()
// Start servicing with listener.
return srv.Server.Serve(listener)
}
// Shutdown - shuts down HTTP server.
func (srv *Server) Shutdown() error {
srv.listenerMutex.Lock()
if srv.listener == nil {
srv.listenerMutex.Unlock()
return errors.New("server not initialized")
}
srv.listenerMutex.Unlock()
if atomic.AddUint32(&srv.inShutdown, 1) > 1 {
// shutdown in progress
return errors.New("http server already in shutdown")
}
// Close underneath HTTP listener.
srv.listenerMutex.Lock()
err := srv.listener.Close()
srv.listenerMutex.Unlock()
// Wait for opened connection to be closed up to Shutdown timeout.
shutdownTimeout := srv.ShutdownTimeout
shutdownTimer := time.NewTimer(shutdownTimeout)
ticker := time.NewTicker(serverShutdownPoll)
defer ticker.Stop()
for {
select {
case <-shutdownTimer.C:
return errors.New("timed out. some connections are still active. doing abnormal shutdown")
case <-ticker.C:
if atomic.LoadInt32(&srv.requestCount) <= 0 {
return err
}
}
}
}
// Secure Go implementations of modern TLS ciphers
// The following ciphers are excluded because:
// - RC4 ciphers: RC4 is broken
// - 3DES ciphers: Because of the 64 bit blocksize of DES (Sweet32)
// - CBC-SHA256 ciphers: No countermeasures against Lucky13 timing attack
// - CBC-SHA ciphers: Legacy ciphers (SHA-1) and non-constant time
// implementation of CBC.
// (CBC-SHA ciphers can be enabled again if required)
// - RSA key exchange ciphers: Disabled because of dangerous PKCS1-v1.5 RSA
// padding scheme. See Bleichenbacher attacks.
var defaultCipherSuites = []uint16{
tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
}
// Go only provides constant-time implementations of Curve25519 and NIST P-256 curve.
var secureCurves = []tls.CurveID{tls.X25519, tls.CurveP256}
// NewServer - creates new HTTP server using given arguments.
func NewServer(addrs []string, handler http.Handler, certificate *tls.Certificate) *Server {
var tlsConfig *tls.Config
if certificate != nil {
tlsConfig = &tls.Config{
PreferServerCipherSuites: true,
CipherSuites: defaultCipherSuites,
CurvePreferences: secureCurves,
MinVersion: tls.VersionTLS12,
NextProtos: []string{"http/1.1", "h2"},
}
tlsConfig.Certificates = append(tlsConfig.Certificates, *certificate)
}
httpServer := &Server{
Addrs: addrs,
ShutdownTimeout: DefaultShutdownTimeout,
TCPKeepAliveTimeout: DefaultTCPKeepAliveTimeout,
listenerMutex: &sync.Mutex{},
}
httpServer.Handler = handler
httpServer.TLSConfig = tlsConfig
httpServer.ReadTimeout = DefaultReadTimeout
httpServer.WriteTimeout = DefaultWriteTimeout
httpServer.MaxHeaderBytes = DefaultMaxHeaderBytes
return httpServer
}