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// Copyright 2017 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.
package net
import (
"errors"
"syscall"
"unsafe"
)
func readRawConn(c syscall.RawConn, b []byte) (int, error) {
var operr error
var n int
err := c.Read(func(s uintptr) bool {
var read uint32
var flags uint32
var buf syscall.WSABuf
buf.Buf = &b[0]
buf.Len = uint32(len(b))
operr = syscall.WSARecv(syscall.Handle(s), &buf, 1, &read, &flags, nil, nil)
n = int(read)
return true
})
if err != nil {
return n, err
}
return n, operr
}
func writeRawConn(c syscall.RawConn, b []byte) error {
var operr error
err := c.Write(func(s uintptr) bool {
var written uint32
var buf syscall.WSABuf
buf.Buf = &b[0]
buf.Len = uint32(len(b))
operr = syscall.WSASend(syscall.Handle(s), &buf, 1, &written, 0, nil, nil)
return true
})
if err != nil {
return err
}
return operr
}
func controlRawConn(c syscall.RawConn, addr Addr) error {
var operr error
fn := func(s uintptr) {
var v, l int32
l = int32(unsafe.Sizeof(v))
operr = syscall.Getsockopt(syscall.Handle(s), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, (*byte)(unsafe.Pointer(&v)), &l)
if operr != nil {
return
}
switch addr := addr.(type) {
case *TCPAddr:
// There's no guarantee that IP-level socket
// options work well with dual stack sockets.
// A simple solution would be to take a look
// at the bound address to the raw connection
// and to classify the address family of the
// underlying socket by the bound address:
//
// - When IP.To16() != nil and IP.To4() == nil,
// we can assume that the raw connection
// consists of an IPv6 socket using only
// IPv6 addresses.
//
// - When IP.To16() == nil and IP.To4() != nil,
// the raw connection consists of an IPv4
// socket using only IPv4 addresses.
//
// - Otherwise, the raw connection is a dual
// stack socket, an IPv6 socket using IPv6
// addresses including IPv4-mapped or
// IPv4-embedded IPv6 addresses.
if addr.IP.To16() != nil && addr.IP.To4() == nil {
operr = syscall.SetsockoptInt(syscall.Handle(s), syscall.IPPROTO_IPV6, syscall.IPV6_UNICAST_HOPS, 1)
} else if addr.IP.To16() == nil && addr.IP.To4() != nil {
operr = syscall.SetsockoptInt(syscall.Handle(s), syscall.IPPROTO_IP, syscall.IP_TTL, 1)
}
}
}
if err := c.Control(fn); err != nil {
return err
}
return operr
}
func controlOnConnSetup(network string, address string, c syscall.RawConn) error {
var operr error
var fn func(uintptr)
switch network {
case "tcp", "udp", "ip":
return errors.New("ambiguous network: " + network)
default:
switch network[len(network)-1] {
case '4':
fn = func(s uintptr) {
operr = syscall.SetsockoptInt(syscall.Handle(s), syscall.IPPROTO_IP, syscall.IP_TTL, 1)
}
case '6':
fn = func(s uintptr) {
operr = syscall.SetsockoptInt(syscall.Handle(s), syscall.IPPROTO_IPV6, syscall.IPV6_UNICAST_HOPS, 1)
}
default:
return errors.New("unknown network: " + network)
}
}
if err := c.Control(fn); err != nil {
return err
}
return operr
}
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