| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * Copyright (C) 2014 Fraunhofer ITWM |
| 4 | * |
| 5 | * Written by: |
| 6 | * Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de> |
| 7 | */ |
| 8 | |
| 9 | #include <linux/ieee802154.h> |
| 10 | |
| 11 | #include <net/mac802154.h> |
| 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 |
| 78 | ieee802154_hdr_push(struct sk_buff *skb, struct ieee802154_hdr *hdr) |
| 79 | { |
| 80 | u8 buf[IEEE802154_MAX_HEADER_LEN]; |
| 81 | int pos = 2; |
| 82 | int rc; |
| 83 | struct ieee802154_hdr_fc *fc = &hdr->fc; |
| 84 | |
| 85 | buf[pos++] = hdr->seq; |
| 86 | |
| 87 | fc->dest_addr_mode = hdr->dest.mode; |
| 88 | |
| 89 | rc = ieee802154_hdr_push_addr(buf + pos, &hdr->dest, false); |
| 90 | if (rc < 0) |
| 91 | return -EINVAL; |
| 92 | pos += rc; |
| 93 | |
| 94 | fc->source_addr_mode = hdr->source.mode; |
| 95 | |
| 96 | if (hdr->source.pan_id == hdr->dest.pan_id && |
| 97 | hdr->dest.mode != IEEE802154_ADDR_NONE) |
| 98 | fc->intra_pan = true; |
| 99 | |
| 100 | rc = ieee802154_hdr_push_addr(buf + pos, &hdr->source, fc->intra_pan); |
| 101 | if (rc < 0) |
| 102 | return -EINVAL; |
| 103 | pos += rc; |
| 104 | |
| 105 | if (fc->security_enabled) { |
| 106 | fc->version = 1; |
| 107 | |
| 108 | rc = ieee802154_hdr_push_sechdr(buf + pos, &hdr->sec); |
| 109 | if (rc < 0) |
| 110 | return -EINVAL; |
| 111 | |
| 112 | pos += rc; |
| 113 | } |
| 114 | |
| 115 | memcpy(buf, fc, 2); |
| 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 | |
| 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 | |
| 198 | static int ieee802154_hdr_sechdr_len(u8 sc) |
| 199 | { |
| 200 | return ieee802154_sechdr_lengths[IEEE802154_SCF_KEY_ID_MODE(sc)]; |
| 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); |
| 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); |