cubefs

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// Copyright 2011 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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// Socket control messages
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package unix
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import "unsafe"
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// UnixCredentials encodes credentials into a socket control message
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// for sending to another process. This can be used for
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// authentication.
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func UnixCredentials(ucred *Ucred) []byte {
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	b := make([]byte, CmsgSpace(SizeofUcred))
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	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
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	h.Level = SOL_SOCKET
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	h.Type = SCM_CREDENTIALS
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	h.SetLen(CmsgLen(SizeofUcred))
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	*(*Ucred)(h.data(0)) = *ucred
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	return b
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}
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// ParseUnixCredentials decodes a socket control message that contains
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// credentials in a Ucred structure. To receive such a message, the
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// SO_PASSCRED option must be enabled on the socket.
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func ParseUnixCredentials(m *SocketControlMessage) (*Ucred, error) {
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	if m.Header.Level != SOL_SOCKET {
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		return nil, EINVAL
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	}
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	if m.Header.Type != SCM_CREDENTIALS {
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		return nil, EINVAL
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	}
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	ucred := *(*Ucred)(unsafe.Pointer(&m.Data[0]))
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	return &ucred, nil
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}
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// PktInfo4 encodes Inet4Pktinfo into a socket control message of type IP_PKTINFO.
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func PktInfo4(info *Inet4Pktinfo) []byte {
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	b := make([]byte, CmsgSpace(SizeofInet4Pktinfo))
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	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
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	h.Level = SOL_IP
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	h.Type = IP_PKTINFO
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	h.SetLen(CmsgLen(SizeofInet4Pktinfo))
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	*(*Inet4Pktinfo)(h.data(0)) = *info
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	return b
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}
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// PktInfo6 encodes Inet6Pktinfo into a socket control message of type IPV6_PKTINFO.
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func PktInfo6(info *Inet6Pktinfo) []byte {
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	b := make([]byte, CmsgSpace(SizeofInet6Pktinfo))
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	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))
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	h.Level = SOL_IPV6
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	h.Type = IPV6_PKTINFO
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	h.SetLen(CmsgLen(SizeofInet6Pktinfo))
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	*(*Inet6Pktinfo)(h.data(0)) = *info
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	return b
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}
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// ParseOrigDstAddr decodes a socket control message containing the original
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// destination address. To receive such a message the IP_RECVORIGDSTADDR or
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// IPV6_RECVORIGDSTADDR option must be enabled on the socket.
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func ParseOrigDstAddr(m *SocketControlMessage) (Sockaddr, error) {
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	switch {
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	case m.Header.Level == SOL_IP && m.Header.Type == IP_ORIGDSTADDR:
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		pp := (*RawSockaddrInet4)(unsafe.Pointer(&m.Data[0]))
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		sa := new(SockaddrInet4)
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		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
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		sa.Port = int(p[0])<<8 + int(p[1])
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		sa.Addr = pp.Addr
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		return sa, nil
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	case m.Header.Level == SOL_IPV6 && m.Header.Type == IPV6_ORIGDSTADDR:
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		pp := (*RawSockaddrInet6)(unsafe.Pointer(&m.Data[0]))
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		sa := new(SockaddrInet6)
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		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
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		sa.Port = int(p[0])<<8 + int(p[1])
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		sa.ZoneId = pp.Scope_id
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		sa.Addr = pp.Addr
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		return sa, nil
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	default:
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		return nil, EINVAL
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	}
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}
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