mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-05 10:02:47 +00:00
118 lines
3.6 KiB
Go
118 lines
3.6 KiB
Go
|
// Copyright 2012 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 ipv4
|
||
|
|
||
|
import (
|
||
|
"net"
|
||
|
|
||
|
"golang.org/x/net/internal/socket"
|
||
|
)
|
||
|
|
||
|
// BUG(mikio): On Windows, the ReadFrom and WriteTo methods of RawConn
|
||
|
// are not implemented.
|
||
|
|
||
|
// A packetHandler represents the IPv4 datagram handler.
|
||
|
type packetHandler struct {
|
||
|
*net.IPConn
|
||
|
*socket.Conn
|
||
|
rawOpt
|
||
|
}
|
||
|
|
||
|
func (c *packetHandler) ok() bool { return c != nil && c.IPConn != nil && c.Conn != nil }
|
||
|
|
||
|
// ReadFrom reads an IPv4 datagram from the endpoint c, copying the
|
||
|
// datagram into b. It returns the received datagram as the IPv4
|
||
|
// header h, the payload p and the control message cm.
|
||
|
func (c *packetHandler) ReadFrom(b []byte) (h *Header, p []byte, cm *ControlMessage, err error) {
|
||
|
if !c.ok() {
|
||
|
return nil, nil, nil, errInvalidConn
|
||
|
}
|
||
|
c.rawOpt.RLock()
|
||
|
m := socket.Message{
|
||
|
Buffers: [][]byte{b},
|
||
|
OOB: NewControlMessage(c.rawOpt.cflags),
|
||
|
}
|
||
|
c.rawOpt.RUnlock()
|
||
|
if err := c.RecvMsg(&m, 0); err != nil {
|
||
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
||
|
}
|
||
|
var hs []byte
|
||
|
if hs, p, err = slicePacket(b[:m.N]); err != nil {
|
||
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
||
|
}
|
||
|
if h, err = ParseHeader(hs); err != nil {
|
||
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
||
|
}
|
||
|
if m.NN > 0 {
|
||
|
if compatFreeBSD32 {
|
||
|
adjustFreeBSD32(&m)
|
||
|
}
|
||
|
cm = new(ControlMessage)
|
||
|
if err := cm.Parse(m.OOB[:m.NN]); err != nil {
|
||
|
return nil, nil, nil, &net.OpError{Op: "read", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Err: err}
|
||
|
}
|
||
|
}
|
||
|
if src, ok := m.Addr.(*net.IPAddr); ok && cm != nil {
|
||
|
cm.Src = src.IP
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
func slicePacket(b []byte) (h, p []byte, err error) {
|
||
|
if len(b) < HeaderLen {
|
||
|
return nil, nil, errHeaderTooShort
|
||
|
}
|
||
|
hdrlen := int(b[0]&0x0f) << 2
|
||
|
return b[:hdrlen], b[hdrlen:], nil
|
||
|
}
|
||
|
|
||
|
// WriteTo writes an IPv4 datagram through the endpoint c, copying the
|
||
|
// datagram from the IPv4 header h and the payload p. The control
|
||
|
// message cm allows the datagram path and the outgoing interface to be
|
||
|
// specified. Currently only Darwin and Linux support this. The cm
|
||
|
// may be nil if control of the outgoing datagram is not required.
|
||
|
//
|
||
|
// The IPv4 header h must contain appropriate fields that include:
|
||
|
//
|
||
|
// Version = <must be specified>
|
||
|
// Len = <must be specified>
|
||
|
// TOS = <must be specified>
|
||
|
// TotalLen = <must be specified>
|
||
|
// ID = platform sets an appropriate value if ID is zero
|
||
|
// FragOff = <must be specified>
|
||
|
// TTL = <must be specified>
|
||
|
// Protocol = <must be specified>
|
||
|
// Checksum = platform sets an appropriate value if Checksum is zero
|
||
|
// Src = platform sets an appropriate value if Src is nil
|
||
|
// Dst = <must be specified>
|
||
|
// Options = optional
|
||
|
func (c *packetHandler) WriteTo(h *Header, p []byte, cm *ControlMessage) error {
|
||
|
if !c.ok() {
|
||
|
return errInvalidConn
|
||
|
}
|
||
|
m := socket.Message{
|
||
|
OOB: cm.Marshal(),
|
||
|
}
|
||
|
wh, err := h.Marshal()
|
||
|
if err != nil {
|
||
|
return err
|
||
|
}
|
||
|
m.Buffers = [][]byte{wh, p}
|
||
|
dst := new(net.IPAddr)
|
||
|
if cm != nil {
|
||
|
if ip := cm.Dst.To4(); ip != nil {
|
||
|
dst.IP = ip
|
||
|
}
|
||
|
}
|
||
|
if dst.IP == nil {
|
||
|
dst.IP = h.Dst
|
||
|
}
|
||
|
m.Addr = dst
|
||
|
if err := c.SendMsg(&m, 0); err != nil {
|
||
|
return &net.OpError{Op: "write", Net: c.IPConn.LocalAddr().Network(), Source: c.IPConn.LocalAddr(), Addr: opAddr(dst), Err: err}
|
||
|
}
|
||
|
return nil
|
||
|
}
|