86 lines
2.8 KiB
Go
86 lines
2.8 KiB
Go
// Copyright 2012 The Go Authors. 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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//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
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// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos
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package ipv4
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import (
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"net"
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"golang.org/x/net/internal/socket"
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)
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// ReadFrom reads a payload of the received IPv4 datagram, from the
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// endpoint c, copying the payload into b. It returns the number of
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// bytes copied into b, the control message cm and the source address
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// src of the received datagram.
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func (c *payloadHandler) ReadFrom(b []byte) (n int, cm *ControlMessage, src net.Addr, err error) {
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if !c.ok() {
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return 0, nil, nil, errInvalidConn
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}
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c.rawOpt.RLock()
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m := socket.Message{
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OOB: NewControlMessage(c.rawOpt.cflags),
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}
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c.rawOpt.RUnlock()
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switch c.PacketConn.(type) {
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case *net.UDPConn:
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m.Buffers = [][]byte{b}
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if err := c.RecvMsg(&m, 0); err != nil {
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return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
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}
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case *net.IPConn:
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h := make([]byte, HeaderLen)
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m.Buffers = [][]byte{h, b}
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if err := c.RecvMsg(&m, 0); err != nil {
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return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
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}
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hdrlen := int(h[0]&0x0f) << 2
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if hdrlen > len(h) {
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d := hdrlen - len(h)
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copy(b, b[d:])
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m.N -= d
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} else {
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m.N -= hdrlen
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}
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default:
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return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: errInvalidConnType}
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}
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if m.NN > 0 {
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if compatFreeBSD32 {
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adjustFreeBSD32(&m)
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}
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cm = new(ControlMessage)
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if err := cm.Parse(m.OOB[:m.NN]); err != nil {
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return 0, nil, nil, &net.OpError{Op: "read", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Err: err}
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}
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cm.Src = netAddrToIP4(m.Addr)
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}
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return m.N, cm, m.Addr, nil
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}
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// WriteTo writes a payload of the IPv4 datagram, to the destination
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// address dst through the endpoint c, copying the payload from b. It
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// returns the number of bytes written. The control message cm allows
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// the datagram path and the outgoing interface to be specified.
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// Currently only Darwin and Linux support this. The cm may be nil if
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// control of the outgoing datagram is not required.
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func (c *payloadHandler) WriteTo(b []byte, cm *ControlMessage, dst net.Addr) (n int, err error) {
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if !c.ok() {
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return 0, errInvalidConn
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}
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m := socket.Message{
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Buffers: [][]byte{b},
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OOB: cm.Marshal(),
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Addr: dst,
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}
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err = c.SendMsg(&m, 0)
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if err != nil {
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err = &net.OpError{Op: "write", Net: c.PacketConn.LocalAddr().Network(), Source: c.PacketConn.LocalAddr(), Addr: opAddr(dst), Err: err}
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}
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return m.N, err
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}
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