forked from minio/minio
/
listener.go
161 lines (137 loc) · 4.44 KB
/
listener.go
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// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package http
import (
"context"
"fmt"
"net"
"syscall"
)
type acceptResult struct {
conn net.Conn
err error
lidx int
}
// httpListener - HTTP listener capable of handling multiple server addresses.
type httpListener struct {
tcpListeners []*net.TCPListener // underlaying TCP listeners.
acceptCh chan acceptResult // channel where all TCP listeners write accepted connection.
ctx context.Context
ctxCanceler context.CancelFunc
}
// start - starts separate goroutine for each TCP listener. A valid new connection is passed to httpListener.acceptCh.
func (listener *httpListener) start() {
// Closure to send acceptResult to acceptCh.
// It returns true if the result is sent else false if returns when doneCh is closed.
send := func(result acceptResult) bool {
select {
case listener.acceptCh <- result:
// Successfully written to acceptCh
return true
case <-listener.ctx.Done():
return false
}
}
// Closure to handle TCPListener until done channel is closed.
handleListener := func(idx int, tcpListener *net.TCPListener) {
for {
tcpConn, err := tcpListener.AcceptTCP()
if tcpConn != nil {
tcpConn.SetKeepAlive(true)
}
send(acceptResult{tcpConn, err, idx})
}
}
// Start separate goroutine for each TCP listener to handle connection.
for idx, tcpListener := range listener.tcpListeners {
go handleListener(idx, tcpListener)
}
}
// Accept - reads from httpListener.acceptCh for one of previously accepted TCP connection and returns the same.
func (listener *httpListener) Accept() (conn net.Conn, err error) {
select {
case result, ok := <-listener.acceptCh:
if ok {
return result.conn, result.err
}
case <-listener.ctx.Done():
}
return nil, syscall.EINVAL
}
// Close - closes underneath all TCP listeners.
func (listener *httpListener) Close() (err error) {
listener.ctxCanceler()
for i := range listener.tcpListeners {
listener.tcpListeners[i].Close()
}
return nil
}
// Addr - net.Listener interface compatible method returns net.Addr. In case of multiple TCP listeners, it returns '0.0.0.0' as IP address.
func (listener *httpListener) Addr() (addr net.Addr) {
addr = listener.tcpListeners[0].Addr()
if len(listener.tcpListeners) == 1 {
return addr
}
tcpAddr := addr.(*net.TCPAddr)
if ip := net.ParseIP("0.0.0.0"); ip != nil {
tcpAddr.IP = ip
}
addr = tcpAddr
return addr
}
// Addrs - returns all address information of TCP listeners.
func (listener *httpListener) Addrs() (addrs []net.Addr) {
for i := range listener.tcpListeners {
addrs = append(addrs, listener.tcpListeners[i].Addr())
}
return addrs
}
// newHTTPListener - creates new httpListener object which is interface compatible to net.Listener.
// httpListener is capable to
// * listen to multiple addresses
// * controls incoming connections only doing HTTP protocol
func newHTTPListener(ctx context.Context, serverAddrs []string) (listener *httpListener, err error) {
var tcpListeners []*net.TCPListener
// Close all opened listeners on error
defer func() {
if err == nil {
return
}
for _, tcpListener := range tcpListeners {
// Ignore error on close.
tcpListener.Close()
}
}()
for _, serverAddr := range serverAddrs {
var l net.Listener
if l, err = listenCfg.Listen(ctx, "tcp", serverAddr); err != nil {
return nil, err
}
tcpListener, ok := l.(*net.TCPListener)
if !ok {
return nil, fmt.Errorf("unexpected listener type found %v, expected net.TCPListener", l)
}
tcpListeners = append(tcpListeners, tcpListener)
}
listener = &httpListener{
tcpListeners: tcpListeners,
acceptCh: make(chan acceptResult, len(tcpListeners)),
}
listener.ctx, listener.ctxCanceler = context.WithCancel(ctx)
listener.start()
return listener, nil
}