status-go/vendor/github.com/marten-seemann/tcp/rawconn.go

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2021-10-19 13:43:41 +00:00
// Copyright 2017 Mikio Hara. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tcp
import (
"errors"
"net"
"os"
"runtime"
"syscall"
"github.com/mikioh/tcpopt"
)
// A Conn represents an end point that uses TCP connection.
// It allows to set non-portable, platform-dependent TCP-level socket
// options.
type Conn struct {
net.Conn
c syscall.RawConn
}
func (c *Conn) ok() bool { return c != nil && c.Conn != nil && c.c != nil }
func (c *Conn) setOption(level, name int, b []byte) error {
var operr error
fn := func(s uintptr) {
operr = setsockopt(s, level, name, b)
}
if err := c.c.Control(fn); err != nil {
return err
}
return os.NewSyscallError("setsockopt", operr)
}
func (c *Conn) option(level, name int, b []byte) (int, error) {
var operr error
var n int
fn := func(s uintptr) {
n, operr = getsockopt(s, level, name, b)
}
if err := c.c.Control(fn); err != nil {
return 0, err
}
return n, os.NewSyscallError("getsockopt", operr)
}
func (c *Conn) buffered() int {
var operr error
var n int
fn := func(s uintptr) {
var b [4]byte
operr = ioctl(s, options[soBuffered].name, b[:])
if operr != nil {
return
}
n = int(nativeEndian.Uint32(b[:]))
}
err := c.c.Control(fn)
if err != nil || operr != nil {
return -1
}
return n
}
func (c *Conn) available() int {
var operr error
var n int
fn := func(s uintptr) {
var b [4]byte
if runtime.GOOS == "darwin" {
_, operr = getsockopt(s, options[soAvailable].level, options[soAvailable].name, b[:])
} else {
operr = ioctl(s, options[soAvailable].name, b[:])
}
if operr != nil {
return
}
n = int(nativeEndian.Uint32(b[:]))
if runtime.GOOS == "darwin" || runtime.GOOS == "linux" {
var o tcpopt.SendBuffer
_, operr = getsockopt(s, o.Level(), o.Name(), b[:])
if operr != nil {
return
}
n = int(nativeEndian.Uint32(b[:])) - n
}
}
err := c.c.Control(fn)
if err != nil || operr != nil {
return -1
}
return n
}
// NewConn returns a new end point.
func NewConn(c net.Conn) (*Conn, error) {
type tcpConn interface {
SyscallConn() (syscall.RawConn, error)
SetLinger(int) error
}
var _ tcpConn = &net.TCPConn{}
cc := &Conn{Conn: c}
switch c := c.(type) {
case tcpConn:
var err error
cc.c, err = c.SyscallConn()
if err != nil {
return nil, err
}
return cc, nil
default:
return nil, errors.New("unknown connection type")
}
}