fea: access for ceci.

vendor/golang.org/x/sys/unix/sockcmsg_linux.go

@@ -17,7 +17,7 @@ func UnixCredentials(ucred *Ucred) []byte {
 	h.Level = SOL_SOCKET
 	h.Type = SCM_CREDENTIALS
 	h.SetLen(CmsgLen(SizeofUcred))
-	*((*Ucred)(cmsgData(h))) = *ucred
+	*(*Ucred)(h.data(0)) = *ucred
 	return b
 }
 
@@ -34,3 +34,52 @@ func ParseUnixCredentials(m *SocketControlMessage) (*Ucred, error) {
 	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
+}
+
+// ParseOrigDstAddr decodes a socket control message containing the original
+// destination address. To receive such a message the IP_RECVORIGDSTADDR or
+// IPV6_RECVORIGDSTADDR option must be enabled on the socket.
+func ParseOrigDstAddr(m *SocketControlMessage) (Sockaddr, error) {
+	switch {
+	case m.Header.Level == SOL_IP && m.Header.Type == IP_ORIGDSTADDR:
+		pp := (*RawSockaddrInet4)(unsafe.Pointer(&m.Data[0]))
+		sa := new(SockaddrInet4)
+		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
+		sa.Port = int(p[0])<<8 + int(p[1])
+		sa.Addr = pp.Addr
+		return sa, nil
+
+	case m.Header.Level == SOL_IPV6 && m.Header.Type == IPV6_ORIGDSTADDR:
+		pp := (*RawSockaddrInet6)(unsafe.Pointer(&m.Data[0]))
+		sa := new(SockaddrInet6)
+		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
+		sa.Port = int(p[0])<<8 + int(p[1])
+		sa.ZoneId = pp.Scope_id
+		sa.Addr = pp.Addr
+		return sa, nil
+
+	default:
+		return nil, EINVAL
+	}
+}