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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin freebsd linux netbsd openbsd windows
// Sockets
package net
import (
"io"
"syscall"
"time"
)
var listenerBacklog = maxListenerBacklog()
// Generic socket creation.
func socket(net string, f, t, p int, ipv6only bool, ulsa, ursa syscall.Sockaddr, deadline time.Time, toAddr func(syscall.Sockaddr) Addr) (fd *netFD, err error) {
// See ../syscall/exec_unix.go for description of ForkLock.
syscall.ForkLock.RLock()
s, err := syscall.Socket(f, t, p)
if err != nil {
syscall.ForkLock.RUnlock()
return nil, err
}
syscall.CloseOnExec(s)
syscall.ForkLock.RUnlock()
if err = setDefaultSockopts(s, f, t, ipv6only); err != nil {
closesocket(s)
return nil, err
}
if ulsa != nil {
// We provide a socket that listens to a wildcard
// address with reusable UDP port when the given ulsa
// is an appropriate UDP multicast address prefix.
// This makes it possible for a single UDP listener
// to join multiple different group addresses, for
// multiple UDP listeners that listen on the same UDP
// port to join the same group address.
if ulsa, err = listenerSockaddr(s, f, ulsa, toAddr); err != nil {
closesocket(s)
return nil, err
}
if err = syscall.Bind(s, ulsa); err != nil {
closesocket(s)
return nil, err
}
}
if fd, err = newFD(s, f, t, net); err != nil {
closesocket(s)
return nil, err
}
if ursa != nil {
if !deadline.IsZero() {
fd.wdeadline = deadline.UnixNano()
}
if err = fd.connect(ursa); err != nil {
closesocket(s)
fd.Close()
return nil, err
}
fd.isConnected = true
fd.wdeadline = 0
}
lsa, _ := syscall.Getsockname(s)
laddr := toAddr(lsa)
rsa, _ := syscall.Getpeername(s)
raddr := toAddr(rsa)
fd.setAddr(laddr, raddr)
return fd, nil
}
type writerOnly struct {
io.Writer
}
// Fallback implementation of io.ReaderFrom's ReadFrom, when sendfile isn't
// applicable.
func genericReadFrom(w io.Writer, r io.Reader) (n int64, err error) {
// Use wrapper to hide existing r.ReadFrom from io.Copy.
return io.Copy(writerOnly{w}, r)
}
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