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