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// Copyright (C) 2016 Nippon Telegraph and Telephone Corporation.
//
// 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.
// +build linux
package server
import (
"fmt"
"net"
"os"
"syscall"
"unsafe"
)
func DialTCPTimeoutWithMD5Sig(host string, port int, key string, msec int) (*net.TCPConn, error) {
var family int
var ra syscall.Sockaddr
ip := net.ParseIP(host)
if ip == nil {
return nil, fmt.Errorf("invalid ip: %s", host)
}
switch {
case ip.To4() != nil:
family = syscall.AF_INET
i := &syscall.SockaddrInet4{
Port: port,
}
for idx, _ := range i.Addr {
i.Addr[idx] = ip.To4()[idx]
}
ra = i
default:
family = syscall.AF_INET6
i := &syscall.SockaddrInet6{
Port: port,
}
for idx, _ := range i.Addr {
i.Addr[idx] = ip[idx]
}
ra = i
}
sotype := syscall.SOCK_STREAM | syscall.SOCK_CLOEXEC
proto := 0
fd, err := syscall.Socket(family, sotype, proto)
if err != nil {
return nil, err
}
t, err := buildTcpMD5Sig(host, key)
if err != nil {
return nil, err
}
if _, _, e := syscall.Syscall6(syscall.SYS_SETSOCKOPT, uintptr(fd),
uintptr(syscall.IPPROTO_TCP), uintptr(TCP_MD5SIG),
uintptr(unsafe.Pointer(&t)), unsafe.Sizeof(t), 0); e > 0 {
return nil, os.NewSyscallError("setsockopt", e)
}
if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1); err != nil {
return nil, os.NewSyscallError("setsockopt", err)
}
if err = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_NODELAY, 1); err != nil {
return nil, os.NewSyscallError("setsockopt", err)
}
tcpconn := func(fd uintptr) (*net.TCPConn, error) {
fi := os.NewFile(uintptr(fd), "")
defer fi.Close()
conn, err := net.FileConn(fi)
return conn.(*net.TCPConn), err
}
err = syscall.Connect(fd, ra)
switch err {
case syscall.EINPROGRESS, syscall.EALREADY, syscall.EINTR:
// do timeout handling
case nil, syscall.EISCONN:
return tcpconn(uintptr(fd))
default:
return nil, os.NewSyscallError("connect", err)
}
epfd, e := syscall.EpollCreate1(syscall.EPOLL_CLOEXEC)
if e != nil {
return nil, e
}
defer syscall.Close(epfd)
var event syscall.EpollEvent
events := make([]syscall.EpollEvent, 1)
event.Events = syscall.EPOLLIN
event.Fd = int32(fd)
if e = syscall.EpollCtl(epfd, syscall.EPOLL_CTL_ADD, fd, &event); e != nil {
return nil, e
}
for {
nevents, e := syscall.EpollWait(epfd, events, msec)
if e != nil {
return nil, e
}
if nevents == 0 {
return nil, fmt.Errorf("timeout")
} else if nevents == 1 && events[0].Fd == int32(fd) {
nerr, err := syscall.GetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_ERROR)
if err != nil {
return nil, os.NewSyscallError("getsockopt", err)
}
switch err := syscall.Errno(nerr); err {
case syscall.EINPROGRESS, syscall.EALREADY, syscall.EINTR:
case syscall.Errno(0), syscall.EISCONN:
return tcpconn(uintptr(fd))
default:
return nil, os.NewSyscallError("getsockopt", err)
}
} else {
return nil, fmt.Errorf("unexpected epoll behavior")
}
}
}
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