rss-tools @ 58cc1bd492af31e6c9acf65e690474c8c1edf164

// Copyright 2024 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.

// Socket control messages

package unix

import "unsafe"

// UnixCredentials encodes credentials into a socket control message

// for sending to another process. This can be used for

// authentication.

func UnixCredentials(ucred *Ucred) []byte {

	b := make([]byte, CmsgSpace(SizeofUcred))

	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))

	h.Level = SOL_SOCKET

	h.Type = SCM_CREDENTIALS

	h.SetLen(CmsgLen(SizeofUcred))

	*(*Ucred)(h.data(0)) = *ucred

	return b

}

// ParseUnixCredentials decodes a socket control message that contains

// credentials in a Ucred structure. To receive such a message, the

// SO_PASSCRED option must be enabled on the socket.

func ParseUnixCredentials(m *SocketControlMessage) (*Ucred, error) {

	if m.Header.Level != SOL_SOCKET {

		return nil, EINVAL

	}

	if m.Header.Type != SCM_CREDENTIALS {

		return nil, EINVAL

	}

	ucred := *(*Ucred)(unsafe.Pointer(&m.Data[0]))

	return &ucred, nil

}

// PktInfo4 encodes Inet4Pktinfo into a socket control message of type IP_PKTINFO.

func PktInfo4(info *Inet4Pktinfo) []byte {

	b := make([]byte, CmsgSpace(SizeofInet4Pktinfo))

	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))

	h.Level = SOL_IP

	h.Type = IP_PKTINFO

	h.SetLen(CmsgLen(SizeofInet4Pktinfo))

	*(*Inet4Pktinfo)(h.data(0)) = *info

	return b

}

// PktInfo6 encodes Inet6Pktinfo into a socket control message of type IPV6_PKTINFO.

func PktInfo6(info *Inet6Pktinfo) []byte {

	b := make([]byte, CmsgSpace(SizeofInet6Pktinfo))

	h := (*Cmsghdr)(unsafe.Pointer(&b[0]))

	h.Level = SOL_IPV6

	h.Type = IPV6_PKTINFO

	h.SetLen(CmsgLen(SizeofInet6Pktinfo))

	*(*Inet6Pktinfo)(h.data(0)) = *info

	return b

}