1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
// Copyright (C) 2015, 2017 Luke Shumaker <lukeshu@sbcglobal.net>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
// 02110-1301 USA
package nslcd_proto
import (
"encoding/binary"
"fmt"
"io"
"net"
"reflect"
"golang.org/x/sys/unix"
)
// NslcdError represents a normal, expected error when dealing with
// the nslcd protocol. Passing invalid data to a Write operation is
// *not* an NslcdError, nor is passing a non-pointer to a Read
// operation; those are programming errors, and result in a panic().
type NslcdError string
func (o NslcdError) Error() string {
return string(o)
}
// An nslcdObject is an object with a different network representation
// than a naive structure.
type nslcdObject interface {
// May panic(interface{}) if given invalid data.
//
// May panic(NslcdError) if encountering a network error.
nslcdWrite(fd io.Writer)
}
// An nslcdObjectPtr is a pointer to an object with a different
// network representation than a naive structure.
type nslcdObjectPtr interface {
// May panic(NslcdError) if encountering a network error.
nslcdRead(fd io.Reader)
}
// Write an object to a stream. In the event of an error, this
// function may panic! Handle it!
func Write(fd io.Writer, data interface{}) {
switch data := data.(type) {
// basic data types
case nslcdObject:
data.nslcdWrite(fd)
case []byte:
if len(data) > 0 {
_, err := fd.Write(data)
if err != nil {
panic(err)
}
}
case int32:
err := binary.Write(fd, binary.BigEndian, data)
if err != nil {
panic(err)
}
// composite datatypes
case string:
Write(fd, int32(len(data)))
Write(fd, []byte(data))
case []string:
Write(fd, int32(len(data)))
for _, item := range data {
Write(fd, item)
}
case net.IP:
var af int32 = -1
switch len(data) {
case net.IPv4len:
af = unix.AF_INET
case net.IPv6len:
af = unix.AF_INET6
}
var bytes []byte
if af < 0 {
bytes = make([]byte, 0)
} else {
bytes = data
}
Write(fd, af)
Write(fd, int32(len(bytes)))
Write(fd, bytes)
case []net.IP:
Write(fd, int32(len(data)))
for _, item := range data {
Write(fd, item)
}
default:
v := reflect.ValueOf(data)
switch v.Kind() {
case reflect.Struct:
for i, n := 0, v.NumField(); i < n; i++ {
Write(fd, v.Field(i).Interface())
}
default:
panic(fmt.Sprintf("Invalid structure to write NSLCD protocol data from: %T ( %#v )", data, data))
}
}
}
// Read an object from a stream. In the event of an error, this
// function may panic! Handle it!
func Read(fd io.Reader, data interface{}) {
switch data := data.(type) {
// basic data types
case nslcdObjectPtr:
data.nslcdRead(fd)
case *[]byte:
if len(*data) > 0 {
_, err := io.ReadFull(fd, *data)
if err != nil {
panic(err)
}
}
case *int32:
err := binary.Read(fd, binary.BigEndian, data)
if err != nil {
panic(err)
}
// composite datatypes
case *string:
var len int32
Read(fd, &len)
buf := make([]byte, len) // BUG(lukeshu): Read: `string` length needs sanity checked
Read(fd, &buf)
*data = string(buf)
case *[]string:
var num int32
Read(fd, &num)
*data = make([]string, num) // BUG(lukeshu): Read: `[]string` length needs sanity checked
for i := 0; i < int(num); i++ {
Read(fd, &((*data)[i]))
}
case *net.IP:
var af int32
Read(fd, &af)
var _len int32
switch af {
case unix.AF_INET:
_len = net.IPv4len
case unix.AF_INET6:
_len = net.IPv6len
default:
panic(NslcdError(fmt.Sprintf("incorrect address family specified: %d", af)))
}
var len int32
Read(fd, &len)
if len != _len {
panic(NslcdError(fmt.Sprintf("address length incorrect: %d", len)))
}
buf := make([]byte, len)
Read(fd, &buf)
*data = buf
case *[]net.IP:
var num int32
Read(fd, &num)
*data = make([]net.IP, num) // BUG(lukeshu): Read: `[]net.IP` length needs sanity checked
for i := 0; i < int(num); i++ {
Read(fd, &((*data)[i]))
}
default:
p := reflect.ValueOf(data)
v := reflect.Indirect(p)
if p == v || v.Kind() != reflect.Struct {
panic(fmt.Sprintf("The argument to nslcd_proto.Read() must be a pointer: %T ( %#v )", data, data))
}
for i, n := 0, v.NumField(); i < n; i++ {
Read(fd, v.Field(i).Addr().Interface())
}
}
}
|
