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Linux 4.8-rc8
[linux/fpc-iii.git] / net / 6lowpan / iphc.c
blob79f1fa22509a350b35340897c1cb137357734713
1 /*
2 * Copyright 2011, Siemens AG
3 * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
4 */
5
6 /* Based on patches from Jon Smirl <jonsmirl@gmail.com>
7 * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 */
19
20 /* Jon's code is based on 6lowpan implementation for Contiki which is:
21 * Copyright (c) 2008, Swedish Institute of Computer Science.
22 * All rights reserved.
23 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 * 3. Neither the name of the Institute nor the names of its contributors
33 * may be used to endorse or promote products derived from this software
34 * without specific prior written permission.
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
37 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
39 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
40 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
41 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
42 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
44 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
45 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 * SUCH DAMAGE.
47 */
48
49 #include <linux/bitops.h>
50 #include <linux/if_arp.h>
51 #include <linux/netdevice.h>
52
53 #include <net/6lowpan.h>
54 #include <net/ipv6.h>
55
56 #include "6lowpan_i.h"
57 #include "nhc.h"
58
59 /* Values of fields within the IPHC encoding first byte */
60 #define LOWPAN_IPHC_TF_MASK 0x18
61 #define LOWPAN_IPHC_TF_00 0x00
62 #define LOWPAN_IPHC_TF_01 0x08
63 #define LOWPAN_IPHC_TF_10 0x10
64 #define LOWPAN_IPHC_TF_11 0x18
65
66 #define LOWPAN_IPHC_NH 0x04
67
68 #define LOWPAN_IPHC_HLIM_MASK 0x03
69 #define LOWPAN_IPHC_HLIM_00 0x00
70 #define LOWPAN_IPHC_HLIM_01 0x01
71 #define LOWPAN_IPHC_HLIM_10 0x02
72 #define LOWPAN_IPHC_HLIM_11 0x03
73
74 /* Values of fields within the IPHC encoding second byte */
75 #define LOWPAN_IPHC_CID 0x80
76
77 #define LOWPAN_IPHC_SAC 0x40
78
79 #define LOWPAN_IPHC_SAM_MASK 0x30
80 #define LOWPAN_IPHC_SAM_00 0x00
81 #define LOWPAN_IPHC_SAM_01 0x10
82 #define LOWPAN_IPHC_SAM_10 0x20
83 #define LOWPAN_IPHC_SAM_11 0x30
84
85 #define LOWPAN_IPHC_M 0x08
86
87 #define LOWPAN_IPHC_DAC 0x04
88
89 #define LOWPAN_IPHC_DAM_MASK 0x03
90 #define LOWPAN_IPHC_DAM_00 0x00
91 #define LOWPAN_IPHC_DAM_01 0x01
92 #define LOWPAN_IPHC_DAM_10 0x02
93 #define LOWPAN_IPHC_DAM_11 0x03
94
95 /* ipv6 address based on mac
96 * second bit-flip (Universe/Local) is done according RFC2464
97 */
98 #define is_addr_mac_addr_based(a, m) \
99 ((((a)->s6_addr[8]) == (((m)[0]) ^ 0x02)) && \
100 (((a)->s6_addr[9]) == (m)[1]) && \
101 (((a)->s6_addr[10]) == (m)[2]) && \
102 (((a)->s6_addr[11]) == (m)[3]) && \
103 (((a)->s6_addr[12]) == (m)[4]) && \
104 (((a)->s6_addr[13]) == (m)[5]) && \
105 (((a)->s6_addr[14]) == (m)[6]) && \
106 (((a)->s6_addr[15]) == (m)[7]))
107
108 /* check whether we can compress the IID to 16 bits,
109 * it's possible for unicast addresses with first 49 bits are zero only.
110 */
111 #define lowpan_is_iid_16_bit_compressable(a) \
112 ((((a)->s6_addr16[4]) == 0) && \
113 (((a)->s6_addr[10]) == 0) && \
114 (((a)->s6_addr[11]) == 0xff) && \
115 (((a)->s6_addr[12]) == 0xfe) && \
116 (((a)->s6_addr[13]) == 0))
117
118 /* check whether the 112-bit gid of the multicast address is mappable to: */
119
120 /* 48 bits, FFXX::00XX:XXXX:XXXX */
121 #define lowpan_is_mcast_addr_compressable48(a) \
122 ((((a)->s6_addr16[1]) == 0) && \
123 (((a)->s6_addr16[2]) == 0) && \
124 (((a)->s6_addr16[3]) == 0) && \
125 (((a)->s6_addr16[4]) == 0) && \
126 (((a)->s6_addr[10]) == 0))
127
128 /* 32 bits, FFXX::00XX:XXXX */
129 #define lowpan_is_mcast_addr_compressable32(a) \
130 ((((a)->s6_addr16[1]) == 0) && \
131 (((a)->s6_addr16[2]) == 0) && \
132 (((a)->s6_addr16[3]) == 0) && \
133 (((a)->s6_addr16[4]) == 0) && \
134 (((a)->s6_addr16[5]) == 0) && \
135 (((a)->s6_addr[12]) == 0))
136
137 /* 8 bits, FF02::00XX */
138 #define lowpan_is_mcast_addr_compressable8(a) \
139 ((((a)->s6_addr[1]) == 2) && \
140 (((a)->s6_addr16[1]) == 0) && \
141 (((a)->s6_addr16[2]) == 0) && \
142 (((a)->s6_addr16[3]) == 0) && \
143 (((a)->s6_addr16[4]) == 0) && \
144 (((a)->s6_addr16[5]) == 0) && \
145 (((a)->s6_addr16[6]) == 0) && \
146 (((a)->s6_addr[14]) == 0))
147
148 #define lowpan_is_linklocal_zero_padded(a) \
149 (!(hdr->saddr.s6_addr[1] & 0x3f) && \
150 !hdr->saddr.s6_addr16[1] && \
151 !hdr->saddr.s6_addr32[1])
152
153 #define LOWPAN_IPHC_CID_DCI(cid) (cid & 0x0f)
154 #define LOWPAN_IPHC_CID_SCI(cid) ((cid & 0xf0) >> 4)
155
156 static inline void
157 lowpan_iphc_uncompress_802154_lladdr(struct in6_addr *ipaddr,
158 const void *lladdr)
159 {
160 const struct ieee802154_addr *addr = lladdr;
161 u8 eui64[EUI64_ADDR_LEN];
162
163 switch (addr->mode) {
164 case IEEE802154_ADDR_LONG:
165 ieee802154_le64_to_be64(eui64, &addr->extended_addr);
166 lowpan_iphc_uncompress_eui64_lladdr(ipaddr, eui64);
167 break;
168 case IEEE802154_ADDR_SHORT:
169 /* fe:80::ff:fe00:XXXX
170 * \__/
171 * short_addr
172 *
173 * Universe/Local bit is zero.
174 */
175 ipaddr->s6_addr[0] = 0xFE;
176 ipaddr->s6_addr[1] = 0x80;
177 ipaddr->s6_addr[11] = 0xFF;
178 ipaddr->s6_addr[12] = 0xFE;
179 ieee802154_le16_to_be16(&ipaddr->s6_addr16[7],
180 &addr->short_addr);
181 break;
182 default:
183 /* should never handled and filtered by 802154 6lowpan */
184 WARN_ON_ONCE(1);
185 break;
186 }
187 }
188
189 static struct lowpan_iphc_ctx *
190 lowpan_iphc_ctx_get_by_id(const struct net_device *dev, u8 id)
191 {
192 struct lowpan_iphc_ctx *ret = &lowpan_dev(dev)->ctx.table[id];
193
194 if (!lowpan_iphc_ctx_is_active(ret))
195 return NULL;
196
197 return ret;
198 }
199
200 static struct lowpan_iphc_ctx *
201 lowpan_iphc_ctx_get_by_addr(const struct net_device *dev,
202 const struct in6_addr *addr)
203 {
204 struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
205 struct lowpan_iphc_ctx *ret = NULL;
206 struct in6_addr addr_pfx;
207 u8 addr_plen;
208 int i;
209
210 for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++) {
211 /* Check if context is valid. A context that is not valid
212 * MUST NOT be used for compression.
213 */
214 if (!lowpan_iphc_ctx_is_active(&table[i]) ||
215 !lowpan_iphc_ctx_is_compression(&table[i]))
216 continue;
217
218 ipv6_addr_prefix(&addr_pfx, addr, table[i].plen);
219
220 /* if prefix len < 64, the remaining bits until 64th bit is
221 * zero. Otherwise we use table[i]->plen.
222 */
223 if (table[i].plen < 64)
224 addr_plen = 64;
225 else
226 addr_plen = table[i].plen;
227
228 if (ipv6_prefix_equal(&addr_pfx, &table[i].pfx, addr_plen)) {
229 /* remember first match */
230 if (!ret) {
231 ret = &table[i];
232 continue;
233 }
234
235 /* get the context with longest prefix len */
236 if (table[i].plen > ret->plen)
237 ret = &table[i];
238 }
239 }
240
241 return ret;
242 }
243
244 static struct lowpan_iphc_ctx *
245 lowpan_iphc_ctx_get_by_mcast_addr(const struct net_device *dev,
246 const struct in6_addr *addr)
247 {
248 struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
249 struct lowpan_iphc_ctx *ret = NULL;
250 struct in6_addr addr_mcast, network_pfx = {};
251 int i;
252
253 /* init mcast address with */
254 memcpy(&addr_mcast, addr, sizeof(*addr));
255
256 for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++) {
257 /* Check if context is valid. A context that is not valid
258 * MUST NOT be used for compression.
259 */
260 if (!lowpan_iphc_ctx_is_active(&table[i]) ||
261 !lowpan_iphc_ctx_is_compression(&table[i]))
262 continue;
263
264 /* setting plen */
265 addr_mcast.s6_addr[3] = table[i].plen;
266 /* get network prefix to copy into multicast address */
267 ipv6_addr_prefix(&network_pfx, &table[i].pfx,
268 table[i].plen);
269 /* setting network prefix */
270 memcpy(&addr_mcast.s6_addr[4], &network_pfx, 8);
271
272 if (ipv6_addr_equal(addr, &addr_mcast)) {
273 ret = &table[i];
274 break;
275 }
276 }
277
278 return ret;
279 }
280
281 /* Uncompress address function for source and
282 * destination address(non-multicast).
283 *
284 * address_mode is the masked value for sam or dam value
285 */
286 static int lowpan_iphc_uncompress_addr(struct sk_buff *skb,
287 const struct net_device *dev,
288 struct in6_addr *ipaddr,
289 u8 address_mode, const void *lladdr)
290 {
291 bool fail;
292
293 switch (address_mode) {
294 /* SAM and DAM are the same here */
295 case LOWPAN_IPHC_DAM_00:
296 /* for global link addresses */
297 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
298 break;
299 case LOWPAN_IPHC_SAM_01:
300 case LOWPAN_IPHC_DAM_01:
301 /* fe:80::XXXX:XXXX:XXXX:XXXX */
302 ipaddr->s6_addr[0] = 0xFE;
303 ipaddr->s6_addr[1] = 0x80;
304 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
305 break;
306 case LOWPAN_IPHC_SAM_10:
307 case LOWPAN_IPHC_DAM_10:
308 /* fe:80::ff:fe00:XXXX */
309 ipaddr->s6_addr[0] = 0xFE;
310 ipaddr->s6_addr[1] = 0x80;
311 ipaddr->s6_addr[11] = 0xFF;
312 ipaddr->s6_addr[12] = 0xFE;
313 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
314 break;
315 case LOWPAN_IPHC_SAM_11:
316 case LOWPAN_IPHC_DAM_11:
317 fail = false;
318 switch (lowpan_dev(dev)->lltype) {
319 case LOWPAN_LLTYPE_IEEE802154:
320 lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
321 break;
322 default:
323 lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
324 break;
325 }
326 break;
327 default:
328 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
329 return -EINVAL;
330 }
331
332 if (fail) {
333 pr_debug("Failed to fetch skb data\n");
334 return -EIO;
335 }
336
337 raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
338 ipaddr->s6_addr, 16);
339
340 return 0;
341 }
342
343 /* Uncompress address function for source context
344 * based address(non-multicast).
345 */
346 static int lowpan_iphc_uncompress_ctx_addr(struct sk_buff *skb,
347 const struct net_device *dev,
348 const struct lowpan_iphc_ctx *ctx,
349 struct in6_addr *ipaddr,
350 u8 address_mode, const void *lladdr)
351 {
352 bool fail;
353
354 switch (address_mode) {
355 /* SAM and DAM are the same here */
356 case LOWPAN_IPHC_DAM_00:
357 fail = false;
358 /* SAM_00 -> unspec address ::
359 * Do nothing, address is already ::
360 *
361 * DAM 00 -> reserved should never occur.
362 */
363 break;
364 case LOWPAN_IPHC_SAM_01:
365 case LOWPAN_IPHC_DAM_01:
366 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
367 ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
368 break;
369 case LOWPAN_IPHC_SAM_10:
370 case LOWPAN_IPHC_DAM_10:
371 ipaddr->s6_addr[11] = 0xFF;
372 ipaddr->s6_addr[12] = 0xFE;
373 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
374 ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
375 break;
376 case LOWPAN_IPHC_SAM_11:
377 case LOWPAN_IPHC_DAM_11:
378 fail = false;
379 switch (lowpan_dev(dev)->lltype) {
380 case LOWPAN_LLTYPE_IEEE802154:
381 lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
382 break;
383 default:
384 lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
385 break;
386 }
387 ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
388 break;
389 default:
390 pr_debug("Invalid sam value: 0x%x\n", address_mode);
391 return -EINVAL;
392 }
393
394 if (fail) {
395 pr_debug("Failed to fetch skb data\n");
396 return -EIO;
397 }
398
399 raw_dump_inline(NULL,
400 "Reconstructed context based ipv6 src addr is",
401 ipaddr->s6_addr, 16);
402
403 return 0;
404 }
405
406 /* Uncompress function for multicast destination address,
407 * when M bit is set.
408 */
409 static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
410 struct in6_addr *ipaddr,
411 u8 address_mode)
412 {
413 bool fail;
414
415 switch (address_mode) {
416 case LOWPAN_IPHC_DAM_00:
417 /* 00: 128 bits. The full address
418 * is carried in-line.
419 */
420 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
421 break;
422 case LOWPAN_IPHC_DAM_01:
423 /* 01: 48 bits. The address takes
424 * the form ffXX::00XX:XXXX:XXXX.
425 */
426 ipaddr->s6_addr[0] = 0xFF;
427 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
428 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
429 break;
430 case LOWPAN_IPHC_DAM_10:
431 /* 10: 32 bits. The address takes
432 * the form ffXX::00XX:XXXX.
433 */
434 ipaddr->s6_addr[0] = 0xFF;
435 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
436 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
437 break;
438 case LOWPAN_IPHC_DAM_11:
439 /* 11: 8 bits. The address takes
440 * the form ff02::00XX.
441 */
442 ipaddr->s6_addr[0] = 0xFF;
443 ipaddr->s6_addr[1] = 0x02;
444 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
445 break;
446 default:
447 pr_debug("DAM value has a wrong value: 0x%x\n", address_mode);
448 return -EINVAL;
449 }
450
451 if (fail) {
452 pr_debug("Failed to fetch skb data\n");
453 return -EIO;
454 }
455
456 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
457 ipaddr->s6_addr, 16);
458
459 return 0;
460 }
461
462 static int lowpan_uncompress_multicast_ctx_daddr(struct sk_buff *skb,
463 struct lowpan_iphc_ctx *ctx,
464 struct in6_addr *ipaddr,
465 u8 address_mode)
466 {
467 struct in6_addr network_pfx = {};
468 bool fail;
469
470 ipaddr->s6_addr[0] = 0xFF;
471 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 2);
472 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[12], 4);
473 if (fail)
474 return -EIO;
475
476 /* take prefix_len and network prefix from the context */
477 ipaddr->s6_addr[3] = ctx->plen;
478 /* get network prefix to copy into multicast address */
479 ipv6_addr_prefix(&network_pfx, &ctx->pfx, ctx->plen);
480 /* setting network prefix */
481 memcpy(&ipaddr->s6_addr[4], &network_pfx, 8);
482
483 return 0;
484 }
485
486 /* get the ecn values from iphc tf format and set it to ipv6hdr */
487 static inline void lowpan_iphc_tf_set_ecn(struct ipv6hdr *hdr, const u8 *tf)
488 {
489 /* get the two higher bits which is ecn */
490 u8 ecn = tf[0] & 0xc0;
491
492 /* ECN takes 0x30 in hdr->flow_lbl[0] */
493 hdr->flow_lbl[0] |= (ecn >> 2);
494 }
495
496 /* get the dscp values from iphc tf format and set it to ipv6hdr */
497 static inline void lowpan_iphc_tf_set_dscp(struct ipv6hdr *hdr, const u8 *tf)
498 {
499 /* DSCP is at place after ECN */
500 u8 dscp = tf[0] & 0x3f;
501
502 /* The four highest bits need to be set at hdr->priority */
503 hdr->priority |= ((dscp & 0x3c) >> 2);
504 /* The two lower bits is part of hdr->flow_lbl[0] */
505 hdr->flow_lbl[0] |= ((dscp & 0x03) << 6);
506 }
507
508 /* get the flow label values from iphc tf format and set it to ipv6hdr */
509 static inline void lowpan_iphc_tf_set_lbl(struct ipv6hdr *hdr, const u8 *lbl)
510 {
511 /* flow label is always some array started with lower nibble of
512 * flow_lbl[0] and followed with two bytes afterwards. Inside inline
513 * data the flow_lbl position can be different, which will be handled
514 * by lbl pointer. E.g. case "01" vs "00" the traffic class is 8 bit
515 * shifted, the different lbl pointer will handle that.
516 *
517 * The flow label will started at lower nibble of flow_lbl[0], the
518 * higher nibbles are part of DSCP + ECN.
519 */
520 hdr->flow_lbl[0] |= lbl[0] & 0x0f;
521 memcpy(&hdr->flow_lbl[1], &lbl[1], 2);
522 }
523
524 /* lowpan_iphc_tf_decompress - decompress the traffic class.
525 * This function will return zero on success, a value lower than zero if
526 * failed.
527 */
528 static int lowpan_iphc_tf_decompress(struct sk_buff *skb, struct ipv6hdr *hdr,
529 u8 val)
530 {
531 u8 tf[4];
532
533 /* Traffic Class and Flow Label */
534 switch (val) {
535 case LOWPAN_IPHC_TF_00:
536 /* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) */
537 if (lowpan_fetch_skb(skb, tf, 4))
538 return -EINVAL;
539
540 /* 1 2 3
541 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
542 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
543 * |ECN| DSCP | rsv | Flow Label |
544 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
545 */
546 lowpan_iphc_tf_set_ecn(hdr, tf);
547 lowpan_iphc_tf_set_dscp(hdr, tf);
548 lowpan_iphc_tf_set_lbl(hdr, &tf[1]);
549 break;
550 case LOWPAN_IPHC_TF_01:
551 /* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided. */
552 if (lowpan_fetch_skb(skb, tf, 3))
553 return -EINVAL;
554
555 /* 1 2
556 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
557 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
558 * |ECN|rsv| Flow Label |
559 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
560 */
561 lowpan_iphc_tf_set_ecn(hdr, tf);
562 lowpan_iphc_tf_set_lbl(hdr, &tf[0]);
563 break;
564 case LOWPAN_IPHC_TF_10:
565 /* ECN + DSCP (1 byte), Flow Label is elided. */
566 if (lowpan_fetch_skb(skb, tf, 1))
567 return -EINVAL;
568
569 /* 0 1 2 3 4 5 6 7
570 * +-+-+-+-+-+-+-+-+
571 * |ECN| DSCP |
572 * +-+-+-+-+-+-+-+-+
573 */
574 lowpan_iphc_tf_set_ecn(hdr, tf);
575 lowpan_iphc_tf_set_dscp(hdr, tf);
576 break;
577 case LOWPAN_IPHC_TF_11:
578 /* Traffic Class and Flow Label are elided */
579 break;
580 default:
581 WARN_ON_ONCE(1);
582 return -EINVAL;
583 }
584
585 return 0;
586 }
587
588 /* TTL uncompression values */
589 static const u8 lowpan_ttl_values[] = {
590 [LOWPAN_IPHC_HLIM_01] = 1,
591 [LOWPAN_IPHC_HLIM_10] = 64,
592 [LOWPAN_IPHC_HLIM_11] = 255,
593 };
594
595 int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
596 const void *daddr, const void *saddr)
597 {
598 struct ipv6hdr hdr = {};
599 struct lowpan_iphc_ctx *ci;
600 u8 iphc0, iphc1, cid = 0;
601 int err;
602
603 raw_dump_table(__func__, "raw skb data dump uncompressed",
604 skb->data, skb->len);
605
606 if (lowpan_fetch_skb(skb, &iphc0, sizeof(iphc0)) ||
607 lowpan_fetch_skb(skb, &iphc1, sizeof(iphc1)))
608 return -EINVAL;
609
610 hdr.version = 6;
611
612 /* default CID = 0, another if the CID flag is set */
613 if (iphc1 & LOWPAN_IPHC_CID) {
614 if (lowpan_fetch_skb(skb, &cid, sizeof(cid)))
615 return -EINVAL;
616 }
617
618 err = lowpan_iphc_tf_decompress(skb, &hdr,
619 iphc0 & LOWPAN_IPHC_TF_MASK);
620 if (err < 0)
621 return err;
622
623 /* Next Header */
624 if (!(iphc0 & LOWPAN_IPHC_NH)) {
625 /* Next header is carried inline */
626 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
627 return -EINVAL;
628
629 pr_debug("NH flag is set, next header carried inline: %02x\n",
630 hdr.nexthdr);
631 }
632
633 /* Hop Limit */
634 if ((iphc0 & LOWPAN_IPHC_HLIM_MASK) != LOWPAN_IPHC_HLIM_00) {
635 hdr.hop_limit = lowpan_ttl_values[iphc0 & LOWPAN_IPHC_HLIM_MASK];
636 } else {
637 if (lowpan_fetch_skb(skb, &hdr.hop_limit,
638 sizeof(hdr.hop_limit)))
639 return -EINVAL;
640 }
641
642 if (iphc1 & LOWPAN_IPHC_SAC) {
643 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
644 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_SCI(cid));
645 if (!ci) {
646 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
647 return -EINVAL;
648 }
649
650 pr_debug("SAC bit is set. Handle context based source address.\n");
651 err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.saddr,
652 iphc1 & LOWPAN_IPHC_SAM_MASK,
653 saddr);
654 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
655 } else {
656 /* Source address uncompression */
657 pr_debug("source address stateless compression\n");
658 err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.saddr,
659 iphc1 & LOWPAN_IPHC_SAM_MASK,
660 saddr);
661 }
662
663 /* Check on error of previous branch */
664 if (err)
665 return -EINVAL;
666
667 switch (iphc1 & (LOWPAN_IPHC_M | LOWPAN_IPHC_DAC)) {
668 case LOWPAN_IPHC_M | LOWPAN_IPHC_DAC:
669 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
670 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
671 if (!ci) {
672 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
673 return -EINVAL;
674 }
675
676 /* multicast with context */
677 pr_debug("dest: context-based mcast compression\n");
678 err = lowpan_uncompress_multicast_ctx_daddr(skb, ci,
679 &hdr.daddr,
680 iphc1 & LOWPAN_IPHC_DAM_MASK);
681 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
682 break;
683 case LOWPAN_IPHC_M:
684 /* multicast */
685 err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
686 iphc1 & LOWPAN_IPHC_DAM_MASK);
687 break;
688 case LOWPAN_IPHC_DAC:
689 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
690 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
691 if (!ci) {
692 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
693 return -EINVAL;
694 }
695
696 /* Destination address context based uncompression */
697 pr_debug("DAC bit is set. Handle context based destination address.\n");
698 err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.daddr,
699 iphc1 & LOWPAN_IPHC_DAM_MASK,
700 daddr);
701 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
702 break;
703 default:
704 err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.daddr,
705 iphc1 & LOWPAN_IPHC_DAM_MASK,
706 daddr);
707 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
708 iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
709 break;
710 }
711
712 if (err)
713 return -EINVAL;
714
715 /* Next header data uncompression */
716 if (iphc0 & LOWPAN_IPHC_NH) {
717 err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
718 if (err < 0)
719 return err;
720 } else {
721 err = skb_cow(skb, sizeof(hdr));
722 if (unlikely(err))
723 return err;
724 }
725
726 switch (lowpan_dev(dev)->lltype) {
727 case LOWPAN_LLTYPE_IEEE802154:
728 if (lowpan_802154_cb(skb)->d_size)
729 hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
730 sizeof(struct ipv6hdr));
731 else
732 hdr.payload_len = htons(skb->len);
733 break;
734 default:
735 hdr.payload_len = htons(skb->len);
736 break;
737 }
738
739 pr_debug("skb headroom size = %d, data length = %d\n",
740 skb_headroom(skb), skb->len);
741
742 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
743 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
744 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
745 hdr.hop_limit, &hdr.daddr);
746
747 skb_push(skb, sizeof(hdr));
748 skb_reset_network_header(skb);
749 skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
750
751 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
752
753 return 0;
754 }
755 EXPORT_SYMBOL_GPL(lowpan_header_decompress);
756
757 static const u8 lowpan_iphc_dam_to_sam_value[] = {
758 [LOWPAN_IPHC_DAM_00] = LOWPAN_IPHC_SAM_00,
759 [LOWPAN_IPHC_DAM_01] = LOWPAN_IPHC_SAM_01,
760 [LOWPAN_IPHC_DAM_10] = LOWPAN_IPHC_SAM_10,
761 [LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
762 };
763
764 static inline bool
765 lowpan_iphc_compress_ctx_802154_lladdr(const struct in6_addr *ipaddr,
766 const struct lowpan_iphc_ctx *ctx,
767 const void *lladdr)
768 {
769 const struct ieee802154_addr *addr = lladdr;
770 unsigned char extended_addr[EUI64_ADDR_LEN];
771 bool lladdr_compress = false;
772 struct in6_addr tmp = {};
773
774 switch (addr->mode) {
775 case IEEE802154_ADDR_LONG:
776 ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
777 /* check for SAM/DAM = 11 */
778 memcpy(&tmp.s6_addr[8], &extended_addr, EUI64_ADDR_LEN);
779 /* second bit-flip (Universe/Local) is done according RFC2464 */
780 tmp.s6_addr[8] ^= 0x02;
781 /* context information are always used */
782 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
783 if (ipv6_addr_equal(&tmp, ipaddr))
784 lladdr_compress = true;
785 break;
786 case IEEE802154_ADDR_SHORT:
787 tmp.s6_addr[11] = 0xFF;
788 tmp.s6_addr[12] = 0xFE;
789 ieee802154_le16_to_be16(&tmp.s6_addr16[7],
790 &addr->short_addr);
791 /* context information are always used */
792 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
793 if (ipv6_addr_equal(&tmp, ipaddr))
794 lladdr_compress = true;
795 break;
796 default:
797 /* should never handled and filtered by 802154 6lowpan */
798 WARN_ON_ONCE(1);
799 break;
800 }
801
802 return lladdr_compress;
803 }
804
805 static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
806 const struct in6_addr *ipaddr,
807 const struct lowpan_iphc_ctx *ctx,
808 const unsigned char *lladdr, bool sam)
809 {
810 struct in6_addr tmp = {};
811 u8 dam;
812
813 switch (lowpan_dev(dev)->lltype) {
814 case LOWPAN_LLTYPE_IEEE802154:
815 if (lowpan_iphc_compress_ctx_802154_lladdr(ipaddr, ctx,
816 lladdr)) {
817 dam = LOWPAN_IPHC_DAM_11;
818 goto out;
819 }
820 break;
821 default:
822 /* check for SAM/DAM = 11 */
823 memcpy(&tmp.s6_addr[8], lladdr, EUI64_ADDR_LEN);
824 /* second bit-flip (Universe/Local) is done according RFC2464 */
825 tmp.s6_addr[8] ^= 0x02;
826 /* context information are always used */
827 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
828 if (ipv6_addr_equal(&tmp, ipaddr)) {
829 dam = LOWPAN_IPHC_DAM_11;
830 goto out;
831 }
832 break;
833 }
834
835 memset(&tmp, 0, sizeof(tmp));
836 /* check for SAM/DAM = 10 */
837 tmp.s6_addr[11] = 0xFF;
838 tmp.s6_addr[12] = 0xFE;
839 memcpy(&tmp.s6_addr[14], &ipaddr->s6_addr[14], 2);
840 /* context information are always used */
841 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
842 if (ipv6_addr_equal(&tmp, ipaddr)) {
843 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[14], 2);
844 dam = LOWPAN_IPHC_DAM_10;
845 goto out;
846 }
847
848 memset(&tmp, 0, sizeof(tmp));
849 /* check for SAM/DAM = 01, should always match */
850 memcpy(&tmp.s6_addr[8], &ipaddr->s6_addr[8], 8);
851 /* context information are always used */
852 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
853 if (ipv6_addr_equal(&tmp, ipaddr)) {
854 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[8], 8);
855 dam = LOWPAN_IPHC_DAM_01;
856 goto out;
857 }
858
859 WARN_ONCE(1, "context found but no address mode matched\n");
860 return LOWPAN_IPHC_DAM_00;
861 out:
862
863 if (sam)
864 return lowpan_iphc_dam_to_sam_value[dam];
865 else
866 return dam;
867 }
868
869 static inline bool
870 lowpan_iphc_compress_802154_lladdr(const struct in6_addr *ipaddr,
871 const void *lladdr)
872 {
873 const struct ieee802154_addr *addr = lladdr;
874 unsigned char extended_addr[EUI64_ADDR_LEN];
875 bool lladdr_compress = false;
876 struct in6_addr tmp = {};
877
878 switch (addr->mode) {
879 case IEEE802154_ADDR_LONG:
880 ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
881 if (is_addr_mac_addr_based(ipaddr, extended_addr))
882 lladdr_compress = true;
883 break;
884 case IEEE802154_ADDR_SHORT:
885 /* fe:80::ff:fe00:XXXX
886 * \__/
887 * short_addr
888 *
889 * Universe/Local bit is zero.
890 */
891 tmp.s6_addr[0] = 0xFE;
892 tmp.s6_addr[1] = 0x80;
893 tmp.s6_addr[11] = 0xFF;
894 tmp.s6_addr[12] = 0xFE;
895 ieee802154_le16_to_be16(&tmp.s6_addr16[7],
896 &addr->short_addr);
897 if (ipv6_addr_equal(&tmp, ipaddr))
898 lladdr_compress = true;
899 break;
900 default:
901 /* should never handled and filtered by 802154 6lowpan */
902 WARN_ON_ONCE(1);
903 break;
904 }
905
906 return lladdr_compress;
907 }
908
909 static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct net_device *dev,
910 const struct in6_addr *ipaddr,
911 const unsigned char *lladdr, bool sam)
912 {
913 u8 dam = LOWPAN_IPHC_DAM_01;
914
915 switch (lowpan_dev(dev)->lltype) {
916 case LOWPAN_LLTYPE_IEEE802154:
917 if (lowpan_iphc_compress_802154_lladdr(ipaddr, lladdr)) {
918 dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
919 pr_debug("address compression 0 bits\n");
920 goto out;
921 }
922 break;
923 default:
924 if (is_addr_mac_addr_based(ipaddr, lladdr)) {
925 dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
926 pr_debug("address compression 0 bits\n");
927 goto out;
928 }
929 break;
930 }
931
932 if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
933 /* compress IID to 16 bits xxxx::XXXX */
934 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
935 dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
936 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
937 *hc_ptr - 2, 2);
938 goto out;
939 }
940
941 /* do not compress IID => xxxx::IID */
942 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
943 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
944 *hc_ptr - 8, 8);
945
946 out:
947
948 if (sam)
949 return lowpan_iphc_dam_to_sam_value[dam];
950 else
951 return dam;
952 }
953
954 /* lowpan_iphc_get_tc - get the ECN + DCSP fields in hc format */
955 static inline u8 lowpan_iphc_get_tc(const struct ipv6hdr *hdr)
956 {
957 u8 dscp, ecn;
958
959 /* hdr->priority contains the higher bits of dscp, lower are part of
960 * flow_lbl[0]. Note ECN, DCSP is swapped in ipv6 hdr.
961 */
962 dscp = (hdr->priority << 2) | ((hdr->flow_lbl[0] & 0xc0) >> 6);
963 /* ECN is at the two lower bits from first nibble of flow_lbl[0] */
964 ecn = (hdr->flow_lbl[0] & 0x30);
965 /* for pretty debug output, also shift ecn to get the ecn value */
966 pr_debug("ecn 0x%02x dscp 0x%02x\n", ecn >> 4, dscp);
967 /* ECN is at 0x30 now, shift it to have ECN + DCSP */
968 return (ecn << 2) | dscp;
969 }
970
971 /* lowpan_iphc_is_flow_lbl_zero - check if flow label is zero */
972 static inline bool lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr *hdr)
973 {
974 return ((!(hdr->flow_lbl[0] & 0x0f)) &&
975 !hdr->flow_lbl[1] && !hdr->flow_lbl[2]);
976 }
977
978 /* lowpan_iphc_tf_compress - compress the traffic class which is set by
979 * ipv6hdr. Return the corresponding format identifier which is used.
980 */
981 static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
982 {
983 /* get ecn dscp data in a byteformat as: ECN(hi) + DSCP(lo) */
984 u8 tc = lowpan_iphc_get_tc(hdr), tf[4], val;
985
986 /* printout the traffic class in hc format */
987 pr_debug("tc 0x%02x\n", tc);
988
989 if (lowpan_iphc_is_flow_lbl_zero(hdr)) {
990 if (!tc) {
991 /* 11: Traffic Class and Flow Label are elided. */
992 val = LOWPAN_IPHC_TF_11;
993 } else {
994 /* 10: ECN + DSCP (1 byte), Flow Label is elided.
995 *
996 * 0 1 2 3 4 5 6 7
997 * +-+-+-+-+-+-+-+-+
998 * |ECN| DSCP |
999 * +-+-+-+-+-+-+-+-+
1000 */
1001 lowpan_push_hc_data(hc_ptr, &tc, sizeof(tc));
1002 val = LOWPAN_IPHC_TF_10;
1003 }
1004 } else {
1005 /* check if dscp is zero, it's after the first two bit */
1006 if (!(tc & 0x3f)) {
1007 /* 01: ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
1008 *
1009 * 1 2
1010 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
1011 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1012 * |ECN|rsv| Flow Label |
1013 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1014 */
1015 memcpy(&tf[0], &hdr->flow_lbl[0], 3);
1016 /* zero the highest 4-bits, contains DCSP + ECN */
1017 tf[0] &= ~0xf0;
1018 /* set ECN */
1019 tf[0] |= (tc & 0xc0);
1020
1021 lowpan_push_hc_data(hc_ptr, tf, 3);
1022 val = LOWPAN_IPHC_TF_01;
1023 } else {
1024 /* 00: ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
1025 *
1026 * 1 2 3
1027 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1028 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1029 * |ECN| DSCP | rsv | Flow Label |
1030 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1031 */
1032 memcpy(&tf[0], &tc, sizeof(tc));
1033 /* highest nibble of flow_lbl[0] is part of DSCP + ECN
1034 * which will be the 4-bit pad and will be filled with
1035 * zeros afterwards.
1036 */
1037 memcpy(&tf[1], &hdr->flow_lbl[0], 3);
1038 /* zero the 4-bit pad, which is reserved */
1039 tf[1] &= ~0xf0;
1040
1041 lowpan_push_hc_data(hc_ptr, tf, 4);
1042 val = LOWPAN_IPHC_TF_00;
1043 }
1044 }
1045
1046 return val;
1047 }
1048
1049 static u8 lowpan_iphc_mcast_ctx_addr_compress(u8 **hc_ptr,
1050 const struct lowpan_iphc_ctx *ctx,
1051 const struct in6_addr *ipaddr)
1052 {
1053 u8 data[6];
1054
1055 /* flags/scope, reserved (RIID) */
1056 memcpy(data, &ipaddr->s6_addr[1], 2);
1057 /* group ID */
1058 memcpy(&data[1], &ipaddr->s6_addr[11], 4);
1059 lowpan_push_hc_data(hc_ptr, data, 6);
1060
1061 return LOWPAN_IPHC_DAM_00;
1062 }
1063
1064 static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
1065 const struct in6_addr *ipaddr)
1066 {
1067 u8 val;
1068
1069 if (lowpan_is_mcast_addr_compressable8(ipaddr)) {
1070 pr_debug("compressed to 1 octet\n");
1071 /* use last byte */
1072 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[15], 1);
1073 val = LOWPAN_IPHC_DAM_11;
1074 } else if (lowpan_is_mcast_addr_compressable32(ipaddr)) {
1075 pr_debug("compressed to 4 octets\n");
1076 /* second byte + the last three */
1077 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
1078 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[13], 3);
1079 val = LOWPAN_IPHC_DAM_10;
1080 } else if (lowpan_is_mcast_addr_compressable48(ipaddr)) {
1081 pr_debug("compressed to 6 octets\n");
1082 /* second byte + the last five */
1083 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
1084 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[11], 5);
1085 val = LOWPAN_IPHC_DAM_01;
1086 } else {
1087 pr_debug("using full address\n");
1088 lowpan_push_hc_data(hc_ptr, ipaddr->s6_addr, 16);
1089 val = LOWPAN_IPHC_DAM_00;
1090 }
1091
1092 return val;
1093 }
1094
1095 int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
1096 const void *daddr, const void *saddr)
1097 {
1098 u8 iphc0, iphc1, *hc_ptr, cid = 0;
1099 struct ipv6hdr *hdr;
1100 u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
1101 struct lowpan_iphc_ctx *dci, *sci, dci_entry, sci_entry;
1102 int ret, ipv6_daddr_type, ipv6_saddr_type;
1103
1104 if (skb->protocol != htons(ETH_P_IPV6))
1105 return -EINVAL;
1106
1107 hdr = ipv6_hdr(skb);
1108 hc_ptr = head + 2;
1109
1110 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
1111 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
1112 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
1113 hdr->hop_limit, &hdr->daddr);
1114
1115 raw_dump_table(__func__, "raw skb network header dump",
1116 skb_network_header(skb), sizeof(struct ipv6hdr));
1117
1118 /* As we copy some bit-length fields, in the IPHC encoding bytes,
1119 * we sometimes use |=
1120 * If the field is 0, and the current bit value in memory is 1,
1121 * this does not work. We therefore reset the IPHC encoding here
1122 */
1123 iphc0 = LOWPAN_DISPATCH_IPHC;
1124 iphc1 = 0;
1125
1126 raw_dump_table(__func__, "sending raw skb network uncompressed packet",
1127 skb->data, skb->len);
1128
1129 ipv6_daddr_type = ipv6_addr_type(&hdr->daddr);
1130 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
1131 if (ipv6_daddr_type & IPV6_ADDR_MULTICAST)
1132 dci = lowpan_iphc_ctx_get_by_mcast_addr(dev, &hdr->daddr);
1133 else
1134 dci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->daddr);
1135 if (dci) {
1136 memcpy(&dci_entry, dci, sizeof(*dci));
1137 cid |= dci->id;
1138 }
1139 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
1140
1141 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
1142 sci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->saddr);
1143 if (sci) {
1144 memcpy(&sci_entry, sci, sizeof(*sci));
1145 cid |= (sci->id << 4);
1146 }
1147 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
1148
1149 /* if cid is zero it will be compressed */
1150 if (cid) {
1151 iphc1 |= LOWPAN_IPHC_CID;
1152 lowpan_push_hc_data(&hc_ptr, &cid, sizeof(cid));
1153 }
1154
1155 /* Traffic Class, Flow Label compression */
1156 iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
1157
1158 /* NOTE: payload length is always compressed */
1159
1160 /* Check if we provide the nhc format for nexthdr and compression
1161 * functionality. If not nexthdr is handled inline and not compressed.
1162 */
1163 ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr);
1164 if (ret == -ENOENT)
1165 lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
1166 sizeof(hdr->nexthdr));
1167 else
1168 iphc0 |= LOWPAN_IPHC_NH;
1169
1170 /* Hop limit
1171 * if 1: compress, encoding is 01
1172 * if 64: compress, encoding is 10
1173 * if 255: compress, encoding is 11
1174 * else do not compress
1175 */
1176 switch (hdr->hop_limit) {
1177 case 1:
1178 iphc0 |= LOWPAN_IPHC_HLIM_01;
1179 break;
1180 case 64:
1181 iphc0 |= LOWPAN_IPHC_HLIM_10;
1182 break;
1183 case 255:
1184 iphc0 |= LOWPAN_IPHC_HLIM_11;
1185 break;
1186 default:
1187 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
1188 sizeof(hdr->hop_limit));
1189 }
1190
1191 ipv6_saddr_type = ipv6_addr_type(&hdr->saddr);
1192 /* source address compression */
1193 if (ipv6_saddr_type == IPV6_ADDR_ANY) {
1194 pr_debug("source address is unspecified, setting SAC\n");
1195 iphc1 |= LOWPAN_IPHC_SAC;
1196 } else {
1197 if (sci) {
1198 iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
1199 &hdr->saddr,
1200 &sci_entry, saddr,
1201 true);
1202 iphc1 |= LOWPAN_IPHC_SAC;
1203 } else {
1204 if (ipv6_saddr_type & IPV6_ADDR_LINKLOCAL &&
1205 lowpan_is_linklocal_zero_padded(hdr->saddr)) {
1206 iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
1207 &hdr->saddr,
1208 saddr, true);
1209 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
1210 &hdr->saddr, iphc1);
1211 } else {
1212 pr_debug("send the full source address\n");
1213 lowpan_push_hc_data(&hc_ptr,
1214 hdr->saddr.s6_addr, 16);
1215 }
1216 }
1217 }
1218
1219 /* destination address compression */
1220 if (ipv6_daddr_type & IPV6_ADDR_MULTICAST) {
1221 pr_debug("destination address is multicast: ");
1222 iphc1 |= LOWPAN_IPHC_M;
1223 if (dci) {
1224 iphc1 |= lowpan_iphc_mcast_ctx_addr_compress(&hc_ptr,
1225 &dci_entry,
1226 &hdr->daddr);
1227 iphc1 |= LOWPAN_IPHC_DAC;
1228 } else {
1229 iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr,
1230 &hdr->daddr);
1231 }
1232 } else {
1233 if (dci) {
1234 iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
1235 &hdr->daddr,
1236 &dci_entry, daddr,
1237 false);
1238 iphc1 |= LOWPAN_IPHC_DAC;
1239 } else {
1240 if (ipv6_daddr_type & IPV6_ADDR_LINKLOCAL &&
1241 lowpan_is_linklocal_zero_padded(hdr->daddr)) {
1242 iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
1243 &hdr->daddr,
1244 daddr, false);
1245 pr_debug("dest address unicast link-local %pI6c iphc1 0x%02x\n",
1246 &hdr->daddr, iphc1);
1247 } else {
1248 pr_debug("dest address unicast %pI6c\n",
1249 &hdr->daddr);
1250 lowpan_push_hc_data(&hc_ptr,
1251 hdr->daddr.s6_addr, 16);
1252 }
1253 }
1254 }
1255
1256 /* next header compression */
1257 if (iphc0 & LOWPAN_IPHC_NH) {
1258 ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
1259 if (ret < 0)
1260 return ret;
1261 }
1262
1263 head[0] = iphc0;
1264 head[1] = iphc1;
1265
1266 skb_pull(skb, sizeof(struct ipv6hdr));
1267 skb_reset_transport_header(skb);
1268 memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
1269 skb_reset_network_header(skb);
1270
1271 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
1272
1273 raw_dump_table(__func__, "raw skb data dump compressed",
1274 skb->data, skb->len);
1275 return 0;
1276 }
1277 EXPORT_SYMBOL_GPL(lowpan_header_compress);
Linux with added FPC-III support