route_classic.go

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build darwin || dragonfly || freebsd || netbsd
     6  
     7  package route
     8  
     9  import (
    10  	"runtime"
    11  	"syscall"
    12  )
    13  
    14  func (m *RouteMessage) marshal() ([]byte, error) {
    15  	w, ok := wireFormats[m.Type]
    16  	if !ok {
    17  		return nil, errUnsupportedMessage
    18  	}
    19  	l := w.bodyOff + addrsSpace(m.Addrs)
    20  	if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
    21  		// Fix stray pointer writes on macOS.
    22  		// See golang.org/issue/22456.
    23  		l += 1024
    24  	}
    25  	b := make([]byte, l)
    26  	nativeEndian.PutUint16(b[:2], uint16(l))
    27  	if m.Version == 0 {
    28  		b[2] = rtmVersion
    29  	} else {
    30  		b[2] = byte(m.Version)
    31  	}
    32  	b[3] = byte(m.Type)
    33  	nativeEndian.PutUint32(b[8:12], uint32(m.Flags))
    34  	nativeEndian.PutUint16(b[4:6], uint16(m.Index))
    35  	nativeEndian.PutUint32(b[16:20], uint32(m.ID))
    36  	nativeEndian.PutUint32(b[20:24], uint32(m.Seq))
    37  	attrs, err := marshalAddrs(b[w.bodyOff:], m.Addrs)
    38  	if err != nil {
    39  		return nil, err
    40  	}
    41  	if attrs > 0 {
    42  		nativeEndian.PutUint32(b[12:16], uint32(attrs))
    43  	}
    44  	return b, nil
    45  }
    46  
    47  func (w *wireFormat) parseRouteMessage(typ RIBType, b []byte) (Message, error) {
    48  	if len(b) < w.bodyOff {
    49  		return nil, errMessageTooShort
    50  	}
    51  	l := int(nativeEndian.Uint16(b[:2]))
    52  	if len(b) < l {
    53  		return nil, errInvalidMessage
    54  	}
    55  	m := &RouteMessage{
    56  		Version: int(b[2]),
    57  		Type:    int(b[3]),
    58  		Flags:   int(nativeEndian.Uint32(b[8:12])),
    59  		Index:   int(nativeEndian.Uint16(b[4:6])),
    60  		ID:      uintptr(nativeEndian.Uint32(b[16:20])),
    61  		Seq:     int(nativeEndian.Uint32(b[20:24])),
    62  		extOff:  w.extOff,
    63  		raw:     b[:l],
    64  	}
    65  	errno := syscall.Errno(nativeEndian.Uint32(b[28:32]))
    66  	if errno != 0 {
    67  		m.Err = errno
    68  	}
    69  	var err error
    70  	m.Addrs, err = parseAddrs(uint(nativeEndian.Uint32(b[12:16])), parseKernelInetAddr, b[w.bodyOff:])
    71  	if err != nil {
    72  		return nil, err
    73  	}
    74  	return m, nil
    75  }
    76
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