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524cf458 PF |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright (C) 2013 Intel Corporation. All rights reserved. | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <stdint.h> | |
23 | #include <string.h> | |
24 | #include <errno.h> | |
25 | #include <stdio.h> | |
26 | ||
27 | #include "dhcp-internal.h" | |
28 | ||
29 | int dhcp_option_append(uint8_t **buf, size_t *buflen, uint8_t code, | |
30 | size_t optlen, const void *optval) | |
31 | { | |
32 | if (!buf || !buflen) | |
33 | return -EINVAL; | |
34 | ||
35 | switch (code) { | |
36 | ||
37 | case DHCP_OPTION_PAD: | |
38 | case DHCP_OPTION_END: | |
39 | if (*buflen < 1) | |
40 | return -ENOBUFS; | |
41 | ||
42 | (*buf)[0] = code; | |
43 | *buf += 1; | |
44 | *buflen -= 1; | |
45 | break; | |
46 | ||
47 | default: | |
48 | if (*buflen < optlen + 2) | |
49 | return -ENOBUFS; | |
50 | ||
51 | if (!optval) | |
52 | return -EINVAL; | |
53 | ||
54 | (*buf)[0] = code; | |
55 | (*buf)[1] = optlen; | |
56 | memcpy(&(*buf)[2], optval, optlen); | |
57 | ||
58 | *buf += optlen + 2; | |
59 | *buflen -= (optlen + 2); | |
60 | ||
61 | break; | |
62 | } | |
63 | ||
64 | return 0; | |
65 | } | |
66 | ||
67 | static int parse_options(const uint8_t *buf, size_t buflen, uint8_t *overload, | |
68 | uint8_t *message_type, dhcp_option_cb_t cb, | |
69 | void *user_data) | |
70 | { | |
71 | const uint8_t *code = buf; | |
72 | const uint8_t *len; | |
73 | ||
74 | while (buflen > 0) { | |
75 | switch (*code) { | |
76 | case DHCP_OPTION_PAD: | |
77 | buflen -= 1; | |
78 | code++; | |
79 | break; | |
80 | ||
81 | case DHCP_OPTION_END: | |
82 | return 0; | |
83 | ||
84 | case DHCP_OPTION_MESSAGE_TYPE: | |
85 | if (buflen < 3) | |
86 | return -ENOBUFS; | |
87 | buflen -= 3; | |
88 | ||
89 | len = code + 1; | |
90 | if (*len != 1) | |
91 | return -EINVAL; | |
92 | ||
93 | if (message_type) | |
94 | *message_type = *(len + 1); | |
95 | ||
96 | code += 3; | |
97 | ||
98 | break; | |
99 | ||
100 | case DHCP_OPTION_OVERLOAD: | |
101 | if (buflen < 3) | |
102 | return -ENOBUFS; | |
103 | buflen -= 3; | |
104 | ||
105 | len = code + 1; | |
106 | if (*len != 1) | |
107 | return -EINVAL; | |
108 | ||
109 | if (overload) | |
110 | *overload = *(len + 1); | |
111 | ||
112 | code += 3; | |
113 | ||
114 | break; | |
115 | ||
116 | default: | |
117 | if (buflen < 3) | |
118 | return -ENOBUFS; | |
119 | ||
120 | len = code + 1; | |
121 | ||
122 | if (buflen < (size_t)*len + 2) | |
123 | return -EINVAL; | |
124 | buflen -= *len + 2; | |
125 | ||
126 | if (cb) | |
127 | cb(*code, *len, len + 1, user_data); | |
128 | ||
129 | code += *len + 2; | |
130 | ||
131 | break; | |
132 | } | |
133 | } | |
134 | ||
135 | if (buflen) | |
136 | return -EINVAL; | |
137 | ||
138 | return 0; | |
139 | } | |
140 | ||
141 | int dhcp_option_parse(DHCPMessage *message, size_t len, | |
142 | dhcp_option_cb_t cb, void *user_data) | |
143 | { | |
144 | uint8_t overload = 0; | |
145 | uint8_t message_type = 0; | |
146 | uint8_t *opt = (uint8_t *)(message + 1); | |
147 | int res; | |
148 | ||
149 | if (!message) | |
150 | return -EINVAL; | |
151 | ||
152 | if (len < sizeof(DHCPMessage) + 4) | |
153 | return -EINVAL; | |
154 | ||
155 | len -= sizeof(DHCPMessage) + 4; | |
156 | ||
157 | if (opt[0] != 0x63 && opt[1] != 0x82 && opt[2] != 0x53 && | |
158 | opt[3] != 0x63) | |
159 | return -EINVAL; | |
160 | ||
161 | res = parse_options(&opt[4], len, &overload, &message_type, | |
162 | cb, user_data); | |
163 | if (res < 0) | |
164 | return res; | |
165 | ||
166 | if (overload & DHCP_OVERLOAD_FILE) { | |
167 | res = parse_options(message->file, sizeof(message->file), | |
168 | NULL, &message_type, cb, user_data); | |
169 | if (res < 0) | |
170 | return res; | |
171 | } | |
172 | ||
173 | if (overload & DHCP_OVERLOAD_SNAME) { | |
174 | res = parse_options(message->sname, sizeof(message->sname), | |
175 | NULL, &message_type, cb, user_data); | |
176 | if (res < 0) | |
177 | return res; | |
178 | } | |
179 | ||
180 | if (message_type) | |
181 | return message_type; | |
182 | ||
183 | return -ENOMSG; | |
184 | } |