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94b4f6c2 PB |
1 | /* |
2 | * Copyright (C) 2014 Fraunhofer ITWM | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 | |
6 | * as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * Written by: | |
14 | * Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de> | |
15 | */ | |
16 | ||
17 | #include <net/mac802154.h> | |
18 | #include <net/ieee802154.h> | |
19 | #include <net/ieee802154_netdev.h> | |
20 | ||
21 | static int | |
22 | ieee802154_hdr_push_addr(u8 *buf, const struct ieee802154_addr *addr, | |
23 | bool omit_pan) | |
24 | { | |
25 | int pos = 0; | |
26 | ||
27 | if (addr->mode == IEEE802154_ADDR_NONE) | |
28 | return 0; | |
29 | ||
30 | if (!omit_pan) { | |
31 | memcpy(buf + pos, &addr->pan_id, 2); | |
32 | pos += 2; | |
33 | } | |
34 | ||
35 | switch (addr->mode) { | |
36 | case IEEE802154_ADDR_SHORT: | |
37 | memcpy(buf + pos, &addr->short_addr, 2); | |
38 | pos += 2; | |
39 | break; | |
40 | ||
41 | case IEEE802154_ADDR_LONG: | |
42 | memcpy(buf + pos, &addr->extended_addr, IEEE802154_ADDR_LEN); | |
43 | pos += IEEE802154_ADDR_LEN; | |
44 | break; | |
45 | ||
46 | default: | |
47 | return -EINVAL; | |
48 | } | |
49 | ||
50 | return pos; | |
51 | } | |
52 | ||
53 | static int | |
54 | ieee802154_hdr_push_sechdr(u8 *buf, const struct ieee802154_sechdr *hdr) | |
55 | { | |
56 | int pos = 5; | |
57 | ||
58 | memcpy(buf, hdr, 1); | |
59 | memcpy(buf + 1, &hdr->frame_counter, 4); | |
60 | ||
61 | switch (hdr->key_id_mode) { | |
62 | case IEEE802154_SCF_KEY_IMPLICIT: | |
63 | return pos; | |
64 | ||
65 | case IEEE802154_SCF_KEY_INDEX: | |
66 | break; | |
67 | ||
68 | case IEEE802154_SCF_KEY_SHORT_INDEX: | |
69 | memcpy(buf + pos, &hdr->short_src, 4); | |
70 | pos += 4; | |
71 | break; | |
72 | ||
73 | case IEEE802154_SCF_KEY_HW_INDEX: | |
74 | memcpy(buf + pos, &hdr->extended_src, IEEE802154_ADDR_LEN); | |
75 | pos += IEEE802154_ADDR_LEN; | |
76 | break; | |
77 | } | |
78 | ||
79 | buf[pos++] = hdr->key_id; | |
80 | ||
81 | return pos; | |
82 | } | |
83 | ||
84 | int | |
85 | ieee802154_hdr_push(struct sk_buff *skb, const struct ieee802154_hdr *hdr) | |
86 | { | |
87 | u8 buf[MAC802154_FRAME_HARD_HEADER_LEN]; | |
88 | int pos = 2; | |
89 | int rc; | |
90 | struct ieee802154_hdr_fc fc = hdr->fc; | |
91 | ||
92 | buf[pos++] = hdr->seq; | |
93 | ||
94 | fc.dest_addr_mode = hdr->dest.mode; | |
95 | ||
96 | rc = ieee802154_hdr_push_addr(buf + pos, &hdr->dest, false); | |
97 | if (rc < 0) | |
98 | return -EINVAL; | |
99 | pos += rc; | |
100 | ||
101 | fc.source_addr_mode = hdr->source.mode; | |
102 | ||
103 | if (hdr->source.pan_id == hdr->dest.pan_id && | |
104 | hdr->dest.mode != IEEE802154_ADDR_NONE) | |
105 | fc.intra_pan = true; | |
106 | ||
107 | rc = ieee802154_hdr_push_addr(buf + pos, &hdr->source, fc.intra_pan); | |
108 | if (rc < 0) | |
109 | return -EINVAL; | |
110 | pos += rc; | |
111 | ||
112 | if (fc.security_enabled) { | |
113 | fc.version = 1; | |
114 | ||
115 | rc = ieee802154_hdr_push_sechdr(buf + pos, &hdr->sec); | |
116 | if (rc < 0) | |
117 | return -EINVAL; | |
118 | ||
119 | pos += rc; | |
120 | } | |
121 | ||
122 | memcpy(buf, &fc, 2); | |
123 | ||
124 | memcpy(skb_push(skb, pos), buf, pos); | |
125 | ||
126 | return pos; | |
127 | } | |
128 | EXPORT_SYMBOL_GPL(ieee802154_hdr_push); | |
129 | ||
130 | static int | |
131 | ieee802154_hdr_get_addr(const u8 *buf, int mode, bool omit_pan, | |
132 | struct ieee802154_addr *addr) | |
133 | { | |
134 | int pos = 0; | |
135 | ||
136 | addr->mode = mode; | |
137 | ||
138 | if (mode == IEEE802154_ADDR_NONE) | |
139 | return 0; | |
140 | ||
141 | if (!omit_pan) { | |
142 | memcpy(&addr->pan_id, buf + pos, 2); | |
143 | pos += 2; | |
144 | } | |
145 | ||
146 | if (mode == IEEE802154_ADDR_SHORT) { | |
147 | memcpy(&addr->short_addr, buf + pos, 2); | |
148 | return pos + 2; | |
149 | } else { | |
150 | memcpy(&addr->extended_addr, buf + pos, IEEE802154_ADDR_LEN); | |
151 | return pos + IEEE802154_ADDR_LEN; | |
152 | } | |
153 | } | |
154 | ||
155 | static int ieee802154_hdr_addr_len(int mode, bool omit_pan) | |
156 | { | |
157 | int pan_len = omit_pan ? 0 : 2; | |
158 | ||
159 | switch (mode) { | |
160 | case IEEE802154_ADDR_NONE: return 0; | |
161 | case IEEE802154_ADDR_SHORT: return 2 + pan_len; | |
162 | case IEEE802154_ADDR_LONG: return IEEE802154_ADDR_LEN + pan_len; | |
163 | default: return -EINVAL; | |
164 | } | |
165 | } | |
166 | ||
167 | static int | |
168 | ieee802154_hdr_get_sechdr(const u8 *buf, struct ieee802154_sechdr *hdr) | |
169 | { | |
170 | int pos = 5; | |
171 | ||
172 | memcpy(hdr, buf, 1); | |
173 | memcpy(&hdr->frame_counter, buf + 1, 4); | |
174 | ||
175 | switch (hdr->key_id_mode) { | |
176 | case IEEE802154_SCF_KEY_IMPLICIT: | |
177 | return pos; | |
178 | ||
179 | case IEEE802154_SCF_KEY_INDEX: | |
180 | break; | |
181 | ||
182 | case IEEE802154_SCF_KEY_SHORT_INDEX: | |
183 | memcpy(&hdr->short_src, buf + pos, 4); | |
184 | pos += 4; | |
185 | break; | |
186 | ||
187 | case IEEE802154_SCF_KEY_HW_INDEX: | |
188 | memcpy(&hdr->extended_src, buf + pos, IEEE802154_ADDR_LEN); | |
189 | pos += IEEE802154_ADDR_LEN; | |
190 | break; | |
191 | } | |
192 | ||
193 | hdr->key_id = buf[pos++]; | |
194 | ||
195 | return pos; | |
196 | } | |
197 | ||
c3a6114f PB |
198 | static int ieee802154_sechdr_lengths[4] = { |
199 | [IEEE802154_SCF_KEY_IMPLICIT] = 5, | |
200 | [IEEE802154_SCF_KEY_INDEX] = 6, | |
201 | [IEEE802154_SCF_KEY_SHORT_INDEX] = 10, | |
202 | [IEEE802154_SCF_KEY_HW_INDEX] = 14, | |
203 | }; | |
204 | ||
94b4f6c2 PB |
205 | static int ieee802154_hdr_sechdr_len(u8 sc) |
206 | { | |
c3a6114f | 207 | return ieee802154_sechdr_lengths[IEEE802154_SCF_KEY_ID_MODE(sc)]; |
94b4f6c2 PB |
208 | } |
209 | ||
210 | static int ieee802154_hdr_minlen(const struct ieee802154_hdr *hdr) | |
211 | { | |
212 | int dlen, slen; | |
213 | ||
214 | dlen = ieee802154_hdr_addr_len(hdr->fc.dest_addr_mode, false); | |
215 | slen = ieee802154_hdr_addr_len(hdr->fc.source_addr_mode, | |
216 | hdr->fc.intra_pan); | |
217 | ||
218 | if (slen < 0 || dlen < 0) | |
219 | return -EINVAL; | |
220 | ||
221 | return 3 + dlen + slen + hdr->fc.security_enabled; | |
222 | } | |
223 | ||
224 | static int | |
225 | ieee802154_hdr_get_addrs(const u8 *buf, struct ieee802154_hdr *hdr) | |
226 | { | |
227 | int pos = 0; | |
228 | ||
229 | pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.dest_addr_mode, | |
230 | false, &hdr->dest); | |
231 | pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.source_addr_mode, | |
232 | hdr->fc.intra_pan, &hdr->source); | |
233 | ||
234 | if (hdr->fc.intra_pan) | |
235 | hdr->source.pan_id = hdr->dest.pan_id; | |
236 | ||
237 | return pos; | |
238 | } | |
239 | ||
240 | int | |
241 | ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr) | |
242 | { | |
243 | int pos = 3, rc; | |
244 | ||
245 | if (!pskb_may_pull(skb, 3)) | |
246 | return -EINVAL; | |
247 | ||
248 | memcpy(hdr, skb->data, 3); | |
249 | ||
250 | rc = ieee802154_hdr_minlen(hdr); | |
251 | if (rc < 0 || !pskb_may_pull(skb, rc)) | |
252 | return -EINVAL; | |
253 | ||
254 | pos += ieee802154_hdr_get_addrs(skb->data + pos, hdr); | |
255 | ||
256 | if (hdr->fc.security_enabled) { | |
257 | int want = pos + ieee802154_hdr_sechdr_len(skb->data[pos]); | |
258 | ||
259 | if (!pskb_may_pull(skb, want)) | |
260 | return -EINVAL; | |
261 | ||
262 | pos += ieee802154_hdr_get_sechdr(skb->data + pos, &hdr->sec); | |
263 | } | |
264 | ||
265 | skb_pull(skb, pos); | |
266 | return pos; | |
267 | } | |
268 | EXPORT_SYMBOL_GPL(ieee802154_hdr_pull); | |
269 | ||
270 | int | |
271 | ieee802154_hdr_peek_addrs(const struct sk_buff *skb, struct ieee802154_hdr *hdr) | |
272 | { | |
273 | const u8 *buf = skb_mac_header(skb); | |
274 | int pos = 3, rc; | |
275 | ||
276 | if (buf + 3 > skb_tail_pointer(skb)) | |
277 | return -EINVAL; | |
278 | ||
279 | memcpy(hdr, buf, 3); | |
280 | ||
281 | rc = ieee802154_hdr_minlen(hdr); | |
282 | if (rc < 0 || buf + rc > skb_tail_pointer(skb)) | |
283 | return -EINVAL; | |
284 | ||
285 | pos += ieee802154_hdr_get_addrs(buf + pos, hdr); | |
286 | return pos; | |
287 | } | |
288 | EXPORT_SYMBOL_GPL(ieee802154_hdr_peek_addrs); | |
c3a6114f PB |
289 | |
290 | int | |
291 | ieee802154_hdr_peek(const struct sk_buff *skb, struct ieee802154_hdr *hdr) | |
292 | { | |
293 | const u8 *buf = skb_mac_header(skb); | |
294 | int pos; | |
295 | ||
296 | pos = ieee802154_hdr_peek_addrs(skb, hdr); | |
297 | if (pos < 0) | |
298 | return -EINVAL; | |
299 | ||
300 | if (hdr->fc.security_enabled) { | |
301 | u8 key_id_mode = IEEE802154_SCF_KEY_ID_MODE(*(buf + pos)); | |
302 | int want = pos + ieee802154_sechdr_lengths[key_id_mode]; | |
303 | ||
304 | if (buf + want > skb_tail_pointer(skb)) | |
305 | return -EINVAL; | |
306 | ||
307 | pos += ieee802154_hdr_get_sechdr(buf + pos, &hdr->sec); | |
308 | } | |
309 | ||
310 | return pos; | |
311 | } | |
312 | EXPORT_SYMBOL_GPL(ieee802154_hdr_peek); | |
313 | ||
314 | int ieee802154_max_payload(const struct ieee802154_hdr *hdr) | |
315 | { | |
316 | int hlen = ieee802154_hdr_minlen(hdr); | |
317 | ||
318 | if (hdr->fc.security_enabled) { | |
319 | hlen += ieee802154_sechdr_lengths[hdr->sec.key_id_mode] - 1; | |
320 | hlen += ieee802154_sechdr_authtag_len(&hdr->sec); | |
321 | } | |
322 | ||
323 | return IEEE802154_MTU - hlen - IEEE802154_MFR_SIZE; | |
324 | } | |
325 | EXPORT_SYMBOL_GPL(ieee802154_max_payload); |