Naveen Sampath | 04696f7 | 2022-06-13 15:19:14 +0530 | [diff] [blame] | 1 | // Copyright 2011 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 | // Socket control messages |
| 6 | |
| 7 | package unix |
| 8 | |
| 9 | import "unsafe" |
| 10 | |
| 11 | // UnixCredentials encodes credentials into a socket control message |
| 12 | // for sending to another process. This can be used for |
| 13 | // authentication. |
| 14 | func UnixCredentials(ucred *Ucred) []byte { |
| 15 | b := make([]byte, CmsgSpace(SizeofUcred)) |
| 16 | h := (*Cmsghdr)(unsafe.Pointer(&b[0])) |
| 17 | h.Level = SOL_SOCKET |
| 18 | h.Type = SCM_CREDENTIALS |
| 19 | h.SetLen(CmsgLen(SizeofUcred)) |
| 20 | *(*Ucred)(h.data(0)) = *ucred |
| 21 | return b |
| 22 | } |
| 23 | |
| 24 | // ParseUnixCredentials decodes a socket control message that contains |
| 25 | // credentials in a Ucred structure. To receive such a message, the |
| 26 | // SO_PASSCRED option must be enabled on the socket. |
| 27 | func ParseUnixCredentials(m *SocketControlMessage) (*Ucred, error) { |
| 28 | if m.Header.Level != SOL_SOCKET { |
| 29 | return nil, EINVAL |
| 30 | } |
| 31 | if m.Header.Type != SCM_CREDENTIALS { |
| 32 | return nil, EINVAL |
| 33 | } |
| 34 | ucred := *(*Ucred)(unsafe.Pointer(&m.Data[0])) |
| 35 | return &ucred, nil |
| 36 | } |
| 37 | |
| 38 | // PktInfo4 encodes Inet4Pktinfo into a socket control message of type IP_PKTINFO. |
| 39 | func PktInfo4(info *Inet4Pktinfo) []byte { |
| 40 | b := make([]byte, CmsgSpace(SizeofInet4Pktinfo)) |
| 41 | h := (*Cmsghdr)(unsafe.Pointer(&b[0])) |
| 42 | h.Level = SOL_IP |
| 43 | h.Type = IP_PKTINFO |
| 44 | h.SetLen(CmsgLen(SizeofInet4Pktinfo)) |
| 45 | *(*Inet4Pktinfo)(h.data(0)) = *info |
| 46 | return b |
| 47 | } |
| 48 | |
| 49 | // PktInfo6 encodes Inet6Pktinfo into a socket control message of type IPV6_PKTINFO. |
| 50 | func PktInfo6(info *Inet6Pktinfo) []byte { |
| 51 | b := make([]byte, CmsgSpace(SizeofInet6Pktinfo)) |
| 52 | h := (*Cmsghdr)(unsafe.Pointer(&b[0])) |
| 53 | h.Level = SOL_IPV6 |
| 54 | h.Type = IPV6_PKTINFO |
| 55 | h.SetLen(CmsgLen(SizeofInet6Pktinfo)) |
| 56 | *(*Inet6Pktinfo)(h.data(0)) = *info |
| 57 | return b |
| 58 | } |
| 59 | |
| 60 | // ParseOrigDstAddr decodes a socket control message containing the original |
| 61 | // destination address. To receive such a message the IP_RECVORIGDSTADDR or |
| 62 | // IPV6_RECVORIGDSTADDR option must be enabled on the socket. |
| 63 | func ParseOrigDstAddr(m *SocketControlMessage) (Sockaddr, error) { |
| 64 | switch { |
| 65 | case m.Header.Level == SOL_IP && m.Header.Type == IP_ORIGDSTADDR: |
| 66 | pp := (*RawSockaddrInet4)(unsafe.Pointer(&m.Data[0])) |
| 67 | sa := new(SockaddrInet4) |
| 68 | p := (*[2]byte)(unsafe.Pointer(&pp.Port)) |
| 69 | sa.Port = int(p[0])<<8 + int(p[1]) |
| 70 | sa.Addr = pp.Addr |
| 71 | return sa, nil |
| 72 | |
| 73 | case m.Header.Level == SOL_IPV6 && m.Header.Type == IPV6_ORIGDSTADDR: |
| 74 | pp := (*RawSockaddrInet6)(unsafe.Pointer(&m.Data[0])) |
| 75 | sa := new(SockaddrInet6) |
| 76 | p := (*[2]byte)(unsafe.Pointer(&pp.Port)) |
| 77 | sa.Port = int(p[0])<<8 + int(p[1]) |
| 78 | sa.ZoneId = pp.Scope_id |
| 79 | sa.Addr = pp.Addr |
| 80 | return sa, nil |
| 81 | |
| 82 | default: |
| 83 | return nil, EINVAL |
| 84 | } |
| 85 | } |