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1802d0be | 1 | // SPDX-License-Identifier: GPL-2.0-only |
94b4f6c2 PB |
2 | /* |
3 | * Copyright (C) 2014 Fraunhofer ITWM | |
4 | * | |
94b4f6c2 PB |
5 | * Written by: |
6 | * Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de> | |
7 | */ | |
8 | ||
4ca24aca AA |
9 | #include <linux/ieee802154.h> |
10 | ||
94b4f6c2 | 11 | #include <net/mac802154.h> |
94b4f6c2 PB |
12 | #include <net/ieee802154_netdev.h> |
13 | ||
14 | static int | |
15 | ieee802154_hdr_push_addr(u8 *buf, const struct ieee802154_addr *addr, | |
16 | bool omit_pan) | |
17 | { | |
18 | int pos = 0; | |
19 | ||
20 | if (addr->mode == IEEE802154_ADDR_NONE) | |
21 | return 0; | |
22 | ||
23 | if (!omit_pan) { | |
24 | memcpy(buf + pos, &addr->pan_id, 2); | |
25 | pos += 2; | |
26 | } | |
27 | ||
28 | switch (addr->mode) { | |
29 | case IEEE802154_ADDR_SHORT: | |
30 | memcpy(buf + pos, &addr->short_addr, 2); | |
31 | pos += 2; | |
32 | break; | |
33 | ||
34 | case IEEE802154_ADDR_LONG: | |
35 | memcpy(buf + pos, &addr->extended_addr, IEEE802154_ADDR_LEN); | |
36 | pos += IEEE802154_ADDR_LEN; | |
37 | break; | |
38 | ||
39 | default: | |
40 | return -EINVAL; | |
41 | } | |
42 | ||
43 | return pos; | |
44 | } | |
45 | ||
46 | static int | |
47 | ieee802154_hdr_push_sechdr(u8 *buf, const struct ieee802154_sechdr *hdr) | |
48 | { | |
49 | int pos = 5; | |
50 | ||
51 | memcpy(buf, hdr, 1); | |
52 | memcpy(buf + 1, &hdr->frame_counter, 4); | |
53 | ||
54 | switch (hdr->key_id_mode) { | |
55 | case IEEE802154_SCF_KEY_IMPLICIT: | |
56 | return pos; | |
57 | ||
58 | case IEEE802154_SCF_KEY_INDEX: | |
59 | break; | |
60 | ||
61 | case IEEE802154_SCF_KEY_SHORT_INDEX: | |
62 | memcpy(buf + pos, &hdr->short_src, 4); | |
63 | pos += 4; | |
64 | break; | |
65 | ||
66 | case IEEE802154_SCF_KEY_HW_INDEX: | |
67 | memcpy(buf + pos, &hdr->extended_src, IEEE802154_ADDR_LEN); | |
68 | pos += IEEE802154_ADDR_LEN; | |
69 | break; | |
70 | } | |
71 | ||
72 | buf[pos++] = hdr->key_id; | |
73 | ||
74 | return pos; | |
75 | } | |
76 | ||
77 | int | |
a1da67b8 | 78 | ieee802154_hdr_push(struct sk_buff *skb, struct ieee802154_hdr *hdr) |
94b4f6c2 | 79 | { |
87a93e4e | 80 | u8 buf[IEEE802154_MAX_HEADER_LEN]; |
94b4f6c2 PB |
81 | int pos = 2; |
82 | int rc; | |
a1da67b8 | 83 | struct ieee802154_hdr_fc *fc = &hdr->fc; |
94b4f6c2 PB |
84 | |
85 | buf[pos++] = hdr->seq; | |
86 | ||
a1da67b8 | 87 | fc->dest_addr_mode = hdr->dest.mode; |
94b4f6c2 PB |
88 | |
89 | rc = ieee802154_hdr_push_addr(buf + pos, &hdr->dest, false); | |
90 | if (rc < 0) | |
91 | return -EINVAL; | |
92 | pos += rc; | |
93 | ||
a1da67b8 | 94 | fc->source_addr_mode = hdr->source.mode; |
94b4f6c2 PB |
95 | |
96 | if (hdr->source.pan_id == hdr->dest.pan_id && | |
97 | hdr->dest.mode != IEEE802154_ADDR_NONE) | |
a1da67b8 | 98 | fc->intra_pan = true; |
94b4f6c2 | 99 | |
a1da67b8 | 100 | rc = ieee802154_hdr_push_addr(buf + pos, &hdr->source, fc->intra_pan); |
94b4f6c2 PB |
101 | if (rc < 0) |
102 | return -EINVAL; | |
103 | pos += rc; | |
104 | ||
a1da67b8 AA |
105 | if (fc->security_enabled) { |
106 | fc->version = 1; | |
94b4f6c2 PB |
107 | |
108 | rc = ieee802154_hdr_push_sechdr(buf + pos, &hdr->sec); | |
109 | if (rc < 0) | |
110 | return -EINVAL; | |
111 | ||
112 | pos += rc; | |
113 | } | |
114 | ||
a1da67b8 | 115 | memcpy(buf, fc, 2); |
94b4f6c2 PB |
116 | |
117 | memcpy(skb_push(skb, pos), buf, pos); | |
118 | ||
119 | return pos; | |
120 | } | |
121 | EXPORT_SYMBOL_GPL(ieee802154_hdr_push); | |
122 | ||
123 | static int | |
124 | ieee802154_hdr_get_addr(const u8 *buf, int mode, bool omit_pan, | |
125 | struct ieee802154_addr *addr) | |
126 | { | |
127 | int pos = 0; | |
128 | ||
129 | addr->mode = mode; | |
130 | ||
131 | if (mode == IEEE802154_ADDR_NONE) | |
132 | return 0; | |
133 | ||
134 | if (!omit_pan) { | |
135 | memcpy(&addr->pan_id, buf + pos, 2); | |
136 | pos += 2; | |
137 | } | |
138 | ||
139 | if (mode == IEEE802154_ADDR_SHORT) { | |
140 | memcpy(&addr->short_addr, buf + pos, 2); | |
141 | return pos + 2; | |
142 | } else { | |
143 | memcpy(&addr->extended_addr, buf + pos, IEEE802154_ADDR_LEN); | |
144 | return pos + IEEE802154_ADDR_LEN; | |
145 | } | |
146 | } | |
147 | ||
148 | static int ieee802154_hdr_addr_len(int mode, bool omit_pan) | |
149 | { | |
150 | int pan_len = omit_pan ? 0 : 2; | |
151 | ||
152 | switch (mode) { | |
153 | case IEEE802154_ADDR_NONE: return 0; | |
154 | case IEEE802154_ADDR_SHORT: return 2 + pan_len; | |
155 | case IEEE802154_ADDR_LONG: return IEEE802154_ADDR_LEN + pan_len; | |
156 | default: return -EINVAL; | |
157 | } | |
158 | } | |
159 | ||
160 | static int | |
161 | ieee802154_hdr_get_sechdr(const u8 *buf, struct ieee802154_sechdr *hdr) | |
162 | { | |
163 | int pos = 5; | |
164 | ||
165 | memcpy(hdr, buf, 1); | |
166 | memcpy(&hdr->frame_counter, buf + 1, 4); | |
167 | ||
168 | switch (hdr->key_id_mode) { | |
169 | case IEEE802154_SCF_KEY_IMPLICIT: | |
170 | return pos; | |
171 | ||
172 | case IEEE802154_SCF_KEY_INDEX: | |
173 | break; | |
174 | ||
175 | case IEEE802154_SCF_KEY_SHORT_INDEX: | |
176 | memcpy(&hdr->short_src, buf + pos, 4); | |
177 | pos += 4; | |
178 | break; | |
179 | ||
180 | case IEEE802154_SCF_KEY_HW_INDEX: | |
181 | memcpy(&hdr->extended_src, buf + pos, IEEE802154_ADDR_LEN); | |
182 | pos += IEEE802154_ADDR_LEN; | |
183 | break; | |
184 | } | |
185 | ||
186 | hdr->key_id = buf[pos++]; | |
187 | ||
188 | return pos; | |
189 | } | |
190 | ||
c3a6114f PB |
191 | static int ieee802154_sechdr_lengths[4] = { |
192 | [IEEE802154_SCF_KEY_IMPLICIT] = 5, | |
193 | [IEEE802154_SCF_KEY_INDEX] = 6, | |
194 | [IEEE802154_SCF_KEY_SHORT_INDEX] = 10, | |
195 | [IEEE802154_SCF_KEY_HW_INDEX] = 14, | |
196 | }; | |
197 | ||
94b4f6c2 PB |
198 | static int ieee802154_hdr_sechdr_len(u8 sc) |
199 | { | |
c3a6114f | 200 | return ieee802154_sechdr_lengths[IEEE802154_SCF_KEY_ID_MODE(sc)]; |
94b4f6c2 PB |
201 | } |
202 | ||
203 | static int ieee802154_hdr_minlen(const struct ieee802154_hdr *hdr) | |
204 | { | |
205 | int dlen, slen; | |
206 | ||
207 | dlen = ieee802154_hdr_addr_len(hdr->fc.dest_addr_mode, false); | |
208 | slen = ieee802154_hdr_addr_len(hdr->fc.source_addr_mode, | |
209 | hdr->fc.intra_pan); | |
210 | ||
211 | if (slen < 0 || dlen < 0) | |
212 | return -EINVAL; | |
213 | ||
214 | return 3 + dlen + slen + hdr->fc.security_enabled; | |
215 | } | |
216 | ||
217 | static int | |
218 | ieee802154_hdr_get_addrs(const u8 *buf, struct ieee802154_hdr *hdr) | |
219 | { | |
220 | int pos = 0; | |
221 | ||
222 | pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.dest_addr_mode, | |
223 | false, &hdr->dest); | |
224 | pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.source_addr_mode, | |
225 | hdr->fc.intra_pan, &hdr->source); | |
226 | ||
227 | if (hdr->fc.intra_pan) | |
228 | hdr->source.pan_id = hdr->dest.pan_id; | |
229 | ||
230 | return pos; | |
231 | } | |
232 | ||
233 | int | |
234 | ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr) | |
235 | { | |
236 | int pos = 3, rc; | |
237 | ||
238 | if (!pskb_may_pull(skb, 3)) | |
239 | return -EINVAL; | |
240 | ||
241 | memcpy(hdr, skb->data, 3); | |
242 | ||
243 | rc = ieee802154_hdr_minlen(hdr); | |
244 | if (rc < 0 || !pskb_may_pull(skb, rc)) | |
245 | return -EINVAL; | |
246 | ||
247 | pos += ieee802154_hdr_get_addrs(skb->data + pos, hdr); | |
248 | ||
249 | if (hdr->fc.security_enabled) { | |
250 | int want = pos + ieee802154_hdr_sechdr_len(skb->data[pos]); | |
251 | ||
252 | if (!pskb_may_pull(skb, want)) | |
253 | return -EINVAL; | |
254 | ||
255 | pos += ieee802154_hdr_get_sechdr(skb->data + pos, &hdr->sec); | |
256 | } | |
257 | ||
258 | skb_pull(skb, pos); | |
259 | return pos; | |
260 | } | |
261 | EXPORT_SYMBOL_GPL(ieee802154_hdr_pull); | |
262 | ||
263 | int | |
264 | ieee802154_hdr_peek_addrs(const struct sk_buff *skb, struct ieee802154_hdr *hdr) | |
265 | { | |
266 | const u8 *buf = skb_mac_header(skb); | |
267 | int pos = 3, rc; | |
268 | ||
269 | if (buf + 3 > skb_tail_pointer(skb)) | |
270 | return -EINVAL; | |
271 | ||
272 | memcpy(hdr, buf, 3); | |
273 | ||
274 | rc = ieee802154_hdr_minlen(hdr); | |
275 | if (rc < 0 || buf + rc > skb_tail_pointer(skb)) | |
276 | return -EINVAL; | |
277 | ||
278 | pos += ieee802154_hdr_get_addrs(buf + pos, hdr); | |
279 | return pos; | |
280 | } | |
281 | EXPORT_SYMBOL_GPL(ieee802154_hdr_peek_addrs); | |
c3a6114f PB |
282 | |
283 | int | |
284 | ieee802154_hdr_peek(const struct sk_buff *skb, struct ieee802154_hdr *hdr) | |
285 | { | |
286 | const u8 *buf = skb_mac_header(skb); | |
287 | int pos; | |
288 | ||
289 | pos = ieee802154_hdr_peek_addrs(skb, hdr); | |
290 | if (pos < 0) | |
291 | return -EINVAL; | |
292 | ||
293 | if (hdr->fc.security_enabled) { | |
294 | u8 key_id_mode = IEEE802154_SCF_KEY_ID_MODE(*(buf + pos)); | |
295 | int want = pos + ieee802154_sechdr_lengths[key_id_mode]; | |
296 | ||
297 | if (buf + want > skb_tail_pointer(skb)) | |
298 | return -EINVAL; | |
299 | ||
300 | pos += ieee802154_hdr_get_sechdr(buf + pos, &hdr->sec); | |
301 | } | |
302 | ||
303 | return pos; | |
304 | } | |
305 | EXPORT_SYMBOL_GPL(ieee802154_hdr_peek); | |
306 | ||
307 | int ieee802154_max_payload(const struct ieee802154_hdr *hdr) | |
308 | { | |
309 | int hlen = ieee802154_hdr_minlen(hdr); | |
310 | ||
311 | if (hdr->fc.security_enabled) { | |
312 | hlen += ieee802154_sechdr_lengths[hdr->sec.key_id_mode] - 1; | |
313 | hlen += ieee802154_sechdr_authtag_len(&hdr->sec); | |
314 | } | |
315 | ||
316 | return IEEE802154_MTU - hlen - IEEE802154_MFR_SIZE; | |
317 | } | |
318 | EXPORT_SYMBOL_GPL(ieee802154_max_payload); |