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btrfs: check page->mapping when loading free space cache
[linux/fpc-iii.git] / net / 6lowpan / iphc.c
blob52fad5dad9f71599ac8130ebe0efb560b6600945
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 static void lowpan_iphc_uncompress_lladdr(const struct net_device *dev,
282 struct in6_addr *ipaddr,
283 const void *lladdr)
284 {
285 switch (dev->addr_len) {
286 case ETH_ALEN:
287 lowpan_iphc_uncompress_eui48_lladdr(ipaddr, lladdr);
288 break;
289 case EUI64_ADDR_LEN:
290 lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
291 break;
292 default:
293 WARN_ON_ONCE(1);
294 break;
295 }
296 }
297
298 /* Uncompress address function for source and
299 * destination address(non-multicast).
300 *
301 * address_mode is the masked value for sam or dam value
302 */
303 static int lowpan_iphc_uncompress_addr(struct sk_buff *skb,
304 const struct net_device *dev,
305 struct in6_addr *ipaddr,
306 u8 address_mode, const void *lladdr)
307 {
308 bool fail;
309
310 switch (address_mode) {
311 /* SAM and DAM are the same here */
312 case LOWPAN_IPHC_DAM_00:
313 /* for global link addresses */
314 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
315 break;
316 case LOWPAN_IPHC_SAM_01:
317 case LOWPAN_IPHC_DAM_01:
318 /* fe:80::XXXX:XXXX:XXXX:XXXX */
319 ipaddr->s6_addr[0] = 0xFE;
320 ipaddr->s6_addr[1] = 0x80;
321 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
322 break;
323 case LOWPAN_IPHC_SAM_10:
324 case LOWPAN_IPHC_DAM_10:
325 /* fe:80::ff:fe00:XXXX */
326 ipaddr->s6_addr[0] = 0xFE;
327 ipaddr->s6_addr[1] = 0x80;
328 ipaddr->s6_addr[11] = 0xFF;
329 ipaddr->s6_addr[12] = 0xFE;
330 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
331 break;
332 case LOWPAN_IPHC_SAM_11:
333 case LOWPAN_IPHC_DAM_11:
334 fail = false;
335 switch (lowpan_dev(dev)->lltype) {
336 case LOWPAN_LLTYPE_IEEE802154:
337 lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
338 break;
339 default:
340 lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
341 break;
342 }
343 break;
344 default:
345 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
346 return -EINVAL;
347 }
348
349 if (fail) {
350 pr_debug("Failed to fetch skb data\n");
351 return -EIO;
352 }
353
354 raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
355 ipaddr->s6_addr, 16);
356
357 return 0;
358 }
359
360 /* Uncompress address function for source context
361 * based address(non-multicast).
362 */
363 static int lowpan_iphc_uncompress_ctx_addr(struct sk_buff *skb,
364 const struct net_device *dev,
365 const struct lowpan_iphc_ctx *ctx,
366 struct in6_addr *ipaddr,
367 u8 address_mode, const void *lladdr)
368 {
369 bool fail;
370
371 switch (address_mode) {
372 /* SAM and DAM are the same here */
373 case LOWPAN_IPHC_DAM_00:
374 fail = false;
375 /* SAM_00 -> unspec address ::
376 * Do nothing, address is already ::
377 *
378 * DAM 00 -> reserved should never occur.
379 */
380 break;
381 case LOWPAN_IPHC_SAM_01:
382 case LOWPAN_IPHC_DAM_01:
383 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
384 ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
385 break;
386 case LOWPAN_IPHC_SAM_10:
387 case LOWPAN_IPHC_DAM_10:
388 ipaddr->s6_addr[11] = 0xFF;
389 ipaddr->s6_addr[12] = 0xFE;
390 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
391 ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
392 break;
393 case LOWPAN_IPHC_SAM_11:
394 case LOWPAN_IPHC_DAM_11:
395 fail = false;
396 switch (lowpan_dev(dev)->lltype) {
397 case LOWPAN_LLTYPE_IEEE802154:
398 lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
399 break;
400 default:
401 lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
402 break;
403 }
404 ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
405 break;
406 default:
407 pr_debug("Invalid sam value: 0x%x\n", address_mode);
408 return -EINVAL;
409 }
410
411 if (fail) {
412 pr_debug("Failed to fetch skb data\n");
413 return -EIO;
414 }
415
416 raw_dump_inline(NULL,
417 "Reconstructed context based ipv6 src addr is",
418 ipaddr->s6_addr, 16);
419
420 return 0;
421 }
422
423 /* Uncompress function for multicast destination address,
424 * when M bit is set.
425 */
426 static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
427 struct in6_addr *ipaddr,
428 u8 address_mode)
429 {
430 bool fail;
431
432 switch (address_mode) {
433 case LOWPAN_IPHC_DAM_00:
434 /* 00: 128 bits. The full address
435 * is carried in-line.
436 */
437 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
438 break;
439 case LOWPAN_IPHC_DAM_01:
440 /* 01: 48 bits. The address takes
441 * the form ffXX::00XX:XXXX:XXXX.
442 */
443 ipaddr->s6_addr[0] = 0xFF;
444 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
445 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
446 break;
447 case LOWPAN_IPHC_DAM_10:
448 /* 10: 32 bits. The address takes
449 * the form ffXX::00XX:XXXX.
450 */
451 ipaddr->s6_addr[0] = 0xFF;
452 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
453 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
454 break;
455 case LOWPAN_IPHC_DAM_11:
456 /* 11: 8 bits. The address takes
457 * the form ff02::00XX.
458 */
459 ipaddr->s6_addr[0] = 0xFF;
460 ipaddr->s6_addr[1] = 0x02;
461 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
462 break;
463 default:
464 pr_debug("DAM value has a wrong value: 0x%x\n", address_mode);
465 return -EINVAL;
466 }
467
468 if (fail) {
469 pr_debug("Failed to fetch skb data\n");
470 return -EIO;
471 }
472
473 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
474 ipaddr->s6_addr, 16);
475
476 return 0;
477 }
478
479 static int lowpan_uncompress_multicast_ctx_daddr(struct sk_buff *skb,
480 struct lowpan_iphc_ctx *ctx,
481 struct in6_addr *ipaddr,
482 u8 address_mode)
483 {
484 struct in6_addr network_pfx = {};
485 bool fail;
486
487 ipaddr->s6_addr[0] = 0xFF;
488 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 2);
489 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[12], 4);
490 if (fail)
491 return -EIO;
492
493 /* take prefix_len and network prefix from the context */
494 ipaddr->s6_addr[3] = ctx->plen;
495 /* get network prefix to copy into multicast address */
496 ipv6_addr_prefix(&network_pfx, &ctx->pfx, ctx->plen);
497 /* setting network prefix */
498 memcpy(&ipaddr->s6_addr[4], &network_pfx, 8);
499
500 return 0;
501 }
502
503 /* get the ecn values from iphc tf format and set it to ipv6hdr */
504 static inline void lowpan_iphc_tf_set_ecn(struct ipv6hdr *hdr, const u8 *tf)
505 {
506 /* get the two higher bits which is ecn */
507 u8 ecn = tf[0] & 0xc0;
508
509 /* ECN takes 0x30 in hdr->flow_lbl[0] */
510 hdr->flow_lbl[0] |= (ecn >> 2);
511 }
512
513 /* get the dscp values from iphc tf format and set it to ipv6hdr */
514 static inline void lowpan_iphc_tf_set_dscp(struct ipv6hdr *hdr, const u8 *tf)
515 {
516 /* DSCP is at place after ECN */
517 u8 dscp = tf[0] & 0x3f;
518
519 /* The four highest bits need to be set at hdr->priority */
520 hdr->priority |= ((dscp & 0x3c) >> 2);
521 /* The two lower bits is part of hdr->flow_lbl[0] */
522 hdr->flow_lbl[0] |= ((dscp & 0x03) << 6);
523 }
524
525 /* get the flow label values from iphc tf format and set it to ipv6hdr */
526 static inline void lowpan_iphc_tf_set_lbl(struct ipv6hdr *hdr, const u8 *lbl)
527 {
528 /* flow label is always some array started with lower nibble of
529 * flow_lbl[0] and followed with two bytes afterwards. Inside inline
530 * data the flow_lbl position can be different, which will be handled
531 * by lbl pointer. E.g. case "01" vs "00" the traffic class is 8 bit
532 * shifted, the different lbl pointer will handle that.
533 *
534 * The flow label will started at lower nibble of flow_lbl[0], the
535 * higher nibbles are part of DSCP + ECN.
536 */
537 hdr->flow_lbl[0] |= lbl[0] & 0x0f;
538 memcpy(&hdr->flow_lbl[1], &lbl[1], 2);
539 }
540
541 /* lowpan_iphc_tf_decompress - decompress the traffic class.
542 * This function will return zero on success, a value lower than zero if
543 * failed.
544 */
545 static int lowpan_iphc_tf_decompress(struct sk_buff *skb, struct ipv6hdr *hdr,
546 u8 val)
547 {
548 u8 tf[4];
549
550 /* Traffic Class and Flow Label */
551 switch (val) {
552 case LOWPAN_IPHC_TF_00:
553 /* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) */
554 if (lowpan_fetch_skb(skb, tf, 4))
555 return -EINVAL;
556
557 /* 1 2 3
558 * 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
559 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
560 * |ECN| DSCP | rsv | Flow Label |
561 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
562 */
563 lowpan_iphc_tf_set_ecn(hdr, tf);
564 lowpan_iphc_tf_set_dscp(hdr, tf);
565 lowpan_iphc_tf_set_lbl(hdr, &tf[1]);
566 break;
567 case LOWPAN_IPHC_TF_01:
568 /* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided. */
569 if (lowpan_fetch_skb(skb, tf, 3))
570 return -EINVAL;
571
572 /* 1 2
573 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
574 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
575 * |ECN|rsv| Flow Label |
576 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
577 */
578 lowpan_iphc_tf_set_ecn(hdr, tf);
579 lowpan_iphc_tf_set_lbl(hdr, &tf[0]);
580 break;
581 case LOWPAN_IPHC_TF_10:
582 /* ECN + DSCP (1 byte), Flow Label is elided. */
583 if (lowpan_fetch_skb(skb, tf, 1))
584 return -EINVAL;
585
586 /* 0 1 2 3 4 5 6 7
587 * +-+-+-+-+-+-+-+-+
588 * |ECN| DSCP |
589 * +-+-+-+-+-+-+-+-+
590 */
591 lowpan_iphc_tf_set_ecn(hdr, tf);
592 lowpan_iphc_tf_set_dscp(hdr, tf);
593 break;
594 case LOWPAN_IPHC_TF_11:
595 /* Traffic Class and Flow Label are elided */
596 break;
597 default:
598 WARN_ON_ONCE(1);
599 return -EINVAL;
600 }
601
602 return 0;
603 }
604
605 /* TTL uncompression values */
606 static const u8 lowpan_ttl_values[] = {
607 [LOWPAN_IPHC_HLIM_01] = 1,
608 [LOWPAN_IPHC_HLIM_10] = 64,
609 [LOWPAN_IPHC_HLIM_11] = 255,
610 };
611
612 int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
613 const void *daddr, const void *saddr)
614 {
615 struct ipv6hdr hdr = {};
616 struct lowpan_iphc_ctx *ci;
617 u8 iphc0, iphc1, cid = 0;
618 int err;
619
620 raw_dump_table(__func__, "raw skb data dump uncompressed",
621 skb->data, skb->len);
622
623 if (lowpan_fetch_skb(skb, &iphc0, sizeof(iphc0)) ||
624 lowpan_fetch_skb(skb, &iphc1, sizeof(iphc1)))
625 return -EINVAL;
626
627 hdr.version = 6;
628
629 /* default CID = 0, another if the CID flag is set */
630 if (iphc1 & LOWPAN_IPHC_CID) {
631 if (lowpan_fetch_skb(skb, &cid, sizeof(cid)))
632 return -EINVAL;
633 }
634
635 err = lowpan_iphc_tf_decompress(skb, &hdr,
636 iphc0 & LOWPAN_IPHC_TF_MASK);
637 if (err < 0)
638 return err;
639
640 /* Next Header */
641 if (!(iphc0 & LOWPAN_IPHC_NH)) {
642 /* Next header is carried inline */
643 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
644 return -EINVAL;
645
646 pr_debug("NH flag is set, next header carried inline: %02x\n",
647 hdr.nexthdr);
648 }
649
650 /* Hop Limit */
651 if ((iphc0 & LOWPAN_IPHC_HLIM_MASK) != LOWPAN_IPHC_HLIM_00) {
652 hdr.hop_limit = lowpan_ttl_values[iphc0 & LOWPAN_IPHC_HLIM_MASK];
653 } else {
654 if (lowpan_fetch_skb(skb, &hdr.hop_limit,
655 sizeof(hdr.hop_limit)))
656 return -EINVAL;
657 }
658
659 if (iphc1 & LOWPAN_IPHC_SAC) {
660 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
661 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_SCI(cid));
662 if (!ci) {
663 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
664 return -EINVAL;
665 }
666
667 pr_debug("SAC bit is set. Handle context based source address.\n");
668 err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.saddr,
669 iphc1 & LOWPAN_IPHC_SAM_MASK,
670 saddr);
671 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
672 } else {
673 /* Source address uncompression */
674 pr_debug("source address stateless compression\n");
675 err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.saddr,
676 iphc1 & LOWPAN_IPHC_SAM_MASK,
677 saddr);
678 }
679
680 /* Check on error of previous branch */
681 if (err)
682 return -EINVAL;
683
684 switch (iphc1 & (LOWPAN_IPHC_M | LOWPAN_IPHC_DAC)) {
685 case LOWPAN_IPHC_M | LOWPAN_IPHC_DAC:
686 skb->pkt_type = PACKET_BROADCAST;
687
688 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
689 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
690 if (!ci) {
691 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
692 return -EINVAL;
693 }
694
695 /* multicast with context */
696 pr_debug("dest: context-based mcast compression\n");
697 err = lowpan_uncompress_multicast_ctx_daddr(skb, ci,
698 &hdr.daddr,
699 iphc1 & LOWPAN_IPHC_DAM_MASK);
700 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
701 break;
702 case LOWPAN_IPHC_M:
703 skb->pkt_type = PACKET_BROADCAST;
704
705 /* multicast */
706 err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
707 iphc1 & LOWPAN_IPHC_DAM_MASK);
708 break;
709 case LOWPAN_IPHC_DAC:
710 skb->pkt_type = PACKET_HOST;
711
712 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
713 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
714 if (!ci) {
715 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
716 return -EINVAL;
717 }
718
719 /* Destination address context based uncompression */
720 pr_debug("DAC bit is set. Handle context based destination address.\n");
721 err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.daddr,
722 iphc1 & LOWPAN_IPHC_DAM_MASK,
723 daddr);
724 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
725 break;
726 default:
727 skb->pkt_type = PACKET_HOST;
728
729 err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.daddr,
730 iphc1 & LOWPAN_IPHC_DAM_MASK,
731 daddr);
732 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
733 iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
734 break;
735 }
736
737 if (err)
738 return -EINVAL;
739
740 /* Next header data uncompression */
741 if (iphc0 & LOWPAN_IPHC_NH) {
742 err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
743 if (err < 0)
744 return err;
745 } else {
746 err = skb_cow(skb, sizeof(hdr));
747 if (unlikely(err))
748 return err;
749 }
750
751 switch (lowpan_dev(dev)->lltype) {
752 case LOWPAN_LLTYPE_IEEE802154:
753 if (lowpan_802154_cb(skb)->d_size)
754 hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
755 sizeof(struct ipv6hdr));
756 else
757 hdr.payload_len = htons(skb->len);
758 break;
759 default:
760 hdr.payload_len = htons(skb->len);
761 break;
762 }
763
764 pr_debug("skb headroom size = %d, data length = %d\n",
765 skb_headroom(skb), skb->len);
766
767 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
768 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
769 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
770 hdr.hop_limit, &hdr.daddr);
771
772 skb_push(skb, sizeof(hdr));
773 skb_reset_mac_header(skb);
774 skb_reset_network_header(skb);
775 skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
776
777 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
778
779 return 0;
780 }
781 EXPORT_SYMBOL_GPL(lowpan_header_decompress);
782
783 static const u8 lowpan_iphc_dam_to_sam_value[] = {
784 [LOWPAN_IPHC_DAM_00] = LOWPAN_IPHC_SAM_00,
785 [LOWPAN_IPHC_DAM_01] = LOWPAN_IPHC_SAM_01,
786 [LOWPAN_IPHC_DAM_10] = LOWPAN_IPHC_SAM_10,
787 [LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
788 };
789
790 static inline bool
791 lowpan_iphc_compress_ctx_802154_lladdr(const struct in6_addr *ipaddr,
792 const struct lowpan_iphc_ctx *ctx,
793 const void *lladdr)
794 {
795 const struct ieee802154_addr *addr = lladdr;
796 unsigned char extended_addr[EUI64_ADDR_LEN];
797 bool lladdr_compress = false;
798 struct in6_addr tmp = {};
799
800 switch (addr->mode) {
801 case IEEE802154_ADDR_LONG:
802 ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
803 /* check for SAM/DAM = 11 */
804 memcpy(&tmp.s6_addr[8], &extended_addr, EUI64_ADDR_LEN);
805 /* second bit-flip (Universe/Local) is done according RFC2464 */
806 tmp.s6_addr[8] ^= 0x02;
807 /* context information are always used */
808 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
809 if (ipv6_addr_equal(&tmp, ipaddr))
810 lladdr_compress = true;
811 break;
812 case IEEE802154_ADDR_SHORT:
813 tmp.s6_addr[11] = 0xFF;
814 tmp.s6_addr[12] = 0xFE;
815 ieee802154_le16_to_be16(&tmp.s6_addr16[7],
816 &addr->short_addr);
817 /* context information are always used */
818 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
819 if (ipv6_addr_equal(&tmp, ipaddr))
820 lladdr_compress = true;
821 break;
822 default:
823 /* should never handled and filtered by 802154 6lowpan */
824 WARN_ON_ONCE(1);
825 break;
826 }
827
828 return lladdr_compress;
829 }
830
831 static bool lowpan_iphc_addr_equal(const struct net_device *dev,
832 const struct lowpan_iphc_ctx *ctx,
833 const struct in6_addr *ipaddr,
834 const void *lladdr)
835 {
836 struct in6_addr tmp = {};
837
838 lowpan_iphc_uncompress_lladdr(dev, &tmp, lladdr);
839
840 if (ctx)
841 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
842
843 return ipv6_addr_equal(&tmp, ipaddr);
844 }
845
846 static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
847 const struct in6_addr *ipaddr,
848 const struct lowpan_iphc_ctx *ctx,
849 const unsigned char *lladdr, bool sam)
850 {
851 struct in6_addr tmp = {};
852 u8 dam;
853
854 switch (lowpan_dev(dev)->lltype) {
855 case LOWPAN_LLTYPE_IEEE802154:
856 if (lowpan_iphc_compress_ctx_802154_lladdr(ipaddr, ctx,
857 lladdr)) {
858 dam = LOWPAN_IPHC_DAM_11;
859 goto out;
860 }
861 break;
862 default:
863 if (lowpan_iphc_addr_equal(dev, ctx, ipaddr, lladdr)) {
864 dam = LOWPAN_IPHC_DAM_11;
865 goto out;
866 }
867 break;
868 }
869
870 memset(&tmp, 0, sizeof(tmp));
871 /* check for SAM/DAM = 10 */
872 tmp.s6_addr[11] = 0xFF;
873 tmp.s6_addr[12] = 0xFE;
874 memcpy(&tmp.s6_addr[14], &ipaddr->s6_addr[14], 2);
875 /* context information are always used */
876 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
877 if (ipv6_addr_equal(&tmp, ipaddr)) {
878 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[14], 2);
879 dam = LOWPAN_IPHC_DAM_10;
880 goto out;
881 }
882
883 memset(&tmp, 0, sizeof(tmp));
884 /* check for SAM/DAM = 01, should always match */
885 memcpy(&tmp.s6_addr[8], &ipaddr->s6_addr[8], 8);
886 /* context information are always used */
887 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
888 if (ipv6_addr_equal(&tmp, ipaddr)) {
889 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[8], 8);
890 dam = LOWPAN_IPHC_DAM_01;
891 goto out;
892 }
893
894 WARN_ONCE(1, "context found but no address mode matched\n");
895 return LOWPAN_IPHC_DAM_00;
896 out:
897
898 if (sam)
899 return lowpan_iphc_dam_to_sam_value[dam];
900 else
901 return dam;
902 }
903
904 static inline bool
905 lowpan_iphc_compress_802154_lladdr(const struct in6_addr *ipaddr,
906 const void *lladdr)
907 {
908 const struct ieee802154_addr *addr = lladdr;
909 unsigned char extended_addr[EUI64_ADDR_LEN];
910 bool lladdr_compress = false;
911 struct in6_addr tmp = {};
912
913 switch (addr->mode) {
914 case IEEE802154_ADDR_LONG:
915 ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
916 if (is_addr_mac_addr_based(ipaddr, extended_addr))
917 lladdr_compress = true;
918 break;
919 case IEEE802154_ADDR_SHORT:
920 /* fe:80::ff:fe00:XXXX
921 * \__/
922 * short_addr
923 *
924 * Universe/Local bit is zero.
925 */
926 tmp.s6_addr[0] = 0xFE;
927 tmp.s6_addr[1] = 0x80;
928 tmp.s6_addr[11] = 0xFF;
929 tmp.s6_addr[12] = 0xFE;
930 ieee802154_le16_to_be16(&tmp.s6_addr16[7],
931 &addr->short_addr);
932 if (ipv6_addr_equal(&tmp, ipaddr))
933 lladdr_compress = true;
934 break;
935 default:
936 /* should never handled and filtered by 802154 6lowpan */
937 WARN_ON_ONCE(1);
938 break;
939 }
940
941 return lladdr_compress;
942 }
943
944 static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct net_device *dev,
945 const struct in6_addr *ipaddr,
946 const unsigned char *lladdr, bool sam)
947 {
948 u8 dam = LOWPAN_IPHC_DAM_01;
949
950 switch (lowpan_dev(dev)->lltype) {
951 case LOWPAN_LLTYPE_IEEE802154:
952 if (lowpan_iphc_compress_802154_lladdr(ipaddr, lladdr)) {
953 dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
954 pr_debug("address compression 0 bits\n");
955 goto out;
956 }
957 break;
958 default:
959 if (lowpan_iphc_addr_equal(dev, NULL, ipaddr, lladdr)) {
960 dam = LOWPAN_IPHC_DAM_11;
961 pr_debug("address compression 0 bits\n");
962 goto out;
963 }
964
965 break;
966 }
967
968 if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
969 /* compress IID to 16 bits xxxx::XXXX */
970 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
971 dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
972 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
973 *hc_ptr - 2, 2);
974 goto out;
975 }
976
977 /* do not compress IID => xxxx::IID */
978 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
979 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
980 *hc_ptr - 8, 8);
981
982 out:
983
984 if (sam)
985 return lowpan_iphc_dam_to_sam_value[dam];
986 else
987 return dam;
988 }
989
990 /* lowpan_iphc_get_tc - get the ECN + DCSP fields in hc format */
991 static inline u8 lowpan_iphc_get_tc(const struct ipv6hdr *hdr)
992 {
993 u8 dscp, ecn;
994
995 /* hdr->priority contains the higher bits of dscp, lower are part of
996 * flow_lbl[0]. Note ECN, DCSP is swapped in ipv6 hdr.
997 */
998 dscp = (hdr->priority << 2) | ((hdr->flow_lbl[0] & 0xc0) >> 6);
999 /* ECN is at the two lower bits from first nibble of flow_lbl[0] */
1000 ecn = (hdr->flow_lbl[0] & 0x30);
1001 /* for pretty debug output, also shift ecn to get the ecn value */
1002 pr_debug("ecn 0x%02x dscp 0x%02x\n", ecn >> 4, dscp);
1003 /* ECN is at 0x30 now, shift it to have ECN + DCSP */
1004 return (ecn << 2) | dscp;
1005 }
1006
1007 /* lowpan_iphc_is_flow_lbl_zero - check if flow label is zero */
1008 static inline bool lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr *hdr)
1009 {
1010 return ((!(hdr->flow_lbl[0] & 0x0f)) &&
1011 !hdr->flow_lbl[1] && !hdr->flow_lbl[2]);
1012 }
1013
1014 /* lowpan_iphc_tf_compress - compress the traffic class which is set by
1015 * ipv6hdr. Return the corresponding format identifier which is used.
1016 */
1017 static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
1018 {
1019 /* get ecn dscp data in a byteformat as: ECN(hi) + DSCP(lo) */
1020 u8 tc = lowpan_iphc_get_tc(hdr), tf[4], val;
1021
1022 /* printout the traffic class in hc format */
1023 pr_debug("tc 0x%02x\n", tc);
1024
1025 if (lowpan_iphc_is_flow_lbl_zero(hdr)) {
1026 if (!tc) {
1027 /* 11: Traffic Class and Flow Label are elided. */
1028 val = LOWPAN_IPHC_TF_11;
1029 } else {
1030 /* 10: ECN + DSCP (1 byte), Flow Label is elided.
1031 *
1032 * 0 1 2 3 4 5 6 7
1033 * +-+-+-+-+-+-+-+-+
1034 * |ECN| DSCP |
1035 * +-+-+-+-+-+-+-+-+
1036 */
1037 lowpan_push_hc_data(hc_ptr, &tc, sizeof(tc));
1038 val = LOWPAN_IPHC_TF_10;
1039 }
1040 } else {
1041 /* check if dscp is zero, it's after the first two bit */
1042 if (!(tc & 0x3f)) {
1043 /* 01: ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
1044 *
1045 * 1 2
1046 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
1047 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1048 * |ECN|rsv| Flow Label |
1049 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1050 */
1051 memcpy(&tf[0], &hdr->flow_lbl[0], 3);
1052 /* zero the highest 4-bits, contains DCSP + ECN */
1053 tf[0] &= ~0xf0;
1054 /* set ECN */
1055 tf[0] |= (tc & 0xc0);
1056
1057 lowpan_push_hc_data(hc_ptr, tf, 3);
1058 val = LOWPAN_IPHC_TF_01;
1059 } else {
1060 /* 00: ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
1061 *
1062 * 1 2 3
1063 * 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
1064 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1065 * |ECN| DSCP | rsv | Flow Label |
1066 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1067 */
1068 memcpy(&tf[0], &tc, sizeof(tc));
1069 /* highest nibble of flow_lbl[0] is part of DSCP + ECN
1070 * which will be the 4-bit pad and will be filled with
1071 * zeros afterwards.
1072 */
1073 memcpy(&tf[1], &hdr->flow_lbl[0], 3);
1074 /* zero the 4-bit pad, which is reserved */
1075 tf[1] &= ~0xf0;
1076
1077 lowpan_push_hc_data(hc_ptr, tf, 4);
1078 val = LOWPAN_IPHC_TF_00;
1079 }
1080 }
1081
1082 return val;
1083 }
1084
1085 static u8 lowpan_iphc_mcast_ctx_addr_compress(u8 **hc_ptr,
1086 const struct lowpan_iphc_ctx *ctx,
1087 const struct in6_addr *ipaddr)
1088 {
1089 u8 data[6];
1090
1091 /* flags/scope, reserved (RIID) */
1092 memcpy(data, &ipaddr->s6_addr[1], 2);
1093 /* group ID */
1094 memcpy(&data[1], &ipaddr->s6_addr[11], 4);
1095 lowpan_push_hc_data(hc_ptr, data, 6);
1096
1097 return LOWPAN_IPHC_DAM_00;
1098 }
1099
1100 static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
1101 const struct in6_addr *ipaddr)
1102 {
1103 u8 val;
1104
1105 if (lowpan_is_mcast_addr_compressable8(ipaddr)) {
1106 pr_debug("compressed to 1 octet\n");
1107 /* use last byte */
1108 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[15], 1);
1109 val = LOWPAN_IPHC_DAM_11;
1110 } else if (lowpan_is_mcast_addr_compressable32(ipaddr)) {
1111 pr_debug("compressed to 4 octets\n");
1112 /* second byte + the last three */
1113 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
1114 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[13], 3);
1115 val = LOWPAN_IPHC_DAM_10;
1116 } else if (lowpan_is_mcast_addr_compressable48(ipaddr)) {
1117 pr_debug("compressed to 6 octets\n");
1118 /* second byte + the last five */
1119 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
1120 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[11], 5);
1121 val = LOWPAN_IPHC_DAM_01;
1122 } else {
1123 pr_debug("using full address\n");
1124 lowpan_push_hc_data(hc_ptr, ipaddr->s6_addr, 16);
1125 val = LOWPAN_IPHC_DAM_00;
1126 }
1127
1128 return val;
1129 }
1130
1131 int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
1132 const void *daddr, const void *saddr)
1133 {
1134 u8 iphc0, iphc1, *hc_ptr, cid = 0;
1135 struct ipv6hdr *hdr;
1136 u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
1137 struct lowpan_iphc_ctx *dci, *sci, dci_entry, sci_entry;
1138 int ret, ipv6_daddr_type, ipv6_saddr_type;
1139
1140 if (skb->protocol != htons(ETH_P_IPV6))
1141 return -EINVAL;
1142
1143 hdr = ipv6_hdr(skb);
1144 hc_ptr = head + 2;
1145
1146 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
1147 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
1148 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
1149 hdr->hop_limit, &hdr->daddr);
1150
1151 raw_dump_table(__func__, "raw skb network header dump",
1152 skb_network_header(skb), sizeof(struct ipv6hdr));
1153
1154 /* As we copy some bit-length fields, in the IPHC encoding bytes,
1155 * we sometimes use |=
1156 * If the field is 0, and the current bit value in memory is 1,
1157 * this does not work. We therefore reset the IPHC encoding here
1158 */
1159 iphc0 = LOWPAN_DISPATCH_IPHC;
1160 iphc1 = 0;
1161
1162 raw_dump_table(__func__, "sending raw skb network uncompressed packet",
1163 skb->data, skb->len);
1164
1165 ipv6_daddr_type = ipv6_addr_type(&hdr->daddr);
1166 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
1167 if (ipv6_daddr_type & IPV6_ADDR_MULTICAST)
1168 dci = lowpan_iphc_ctx_get_by_mcast_addr(dev, &hdr->daddr);
1169 else
1170 dci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->daddr);
1171 if (dci) {
1172 memcpy(&dci_entry, dci, sizeof(*dci));
1173 cid |= dci->id;
1174 }
1175 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
1176
1177 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
1178 sci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->saddr);
1179 if (sci) {
1180 memcpy(&sci_entry, sci, sizeof(*sci));
1181 cid |= (sci->id << 4);
1182 }
1183 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
1184
1185 /* if cid is zero it will be compressed */
1186 if (cid) {
1187 iphc1 |= LOWPAN_IPHC_CID;
1188 lowpan_push_hc_data(&hc_ptr, &cid, sizeof(cid));
1189 }
1190
1191 /* Traffic Class, Flow Label compression */
1192 iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
1193
1194 /* NOTE: payload length is always compressed */
1195
1196 /* Check if we provide the nhc format for nexthdr and compression
1197 * functionality. If not nexthdr is handled inline and not compressed.
1198 */
1199 ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr);
1200 if (ret == -ENOENT)
1201 lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
1202 sizeof(hdr->nexthdr));
1203 else
1204 iphc0 |= LOWPAN_IPHC_NH;
1205
1206 /* Hop limit
1207 * if 1: compress, encoding is 01
1208 * if 64: compress, encoding is 10
1209 * if 255: compress, encoding is 11
1210 * else do not compress
1211 */
1212 switch (hdr->hop_limit) {
1213 case 1:
1214 iphc0 |= LOWPAN_IPHC_HLIM_01;
1215 break;
1216 case 64:
1217 iphc0 |= LOWPAN_IPHC_HLIM_10;
1218 break;
1219 case 255:
1220 iphc0 |= LOWPAN_IPHC_HLIM_11;
1221 break;
1222 default:
1223 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
1224 sizeof(hdr->hop_limit));
1225 }
1226
1227 ipv6_saddr_type = ipv6_addr_type(&hdr->saddr);
1228 /* source address compression */
1229 if (ipv6_saddr_type == IPV6_ADDR_ANY) {
1230 pr_debug("source address is unspecified, setting SAC\n");
1231 iphc1 |= LOWPAN_IPHC_SAC;
1232 } else {
1233 if (sci) {
1234 iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
1235 &hdr->saddr,
1236 &sci_entry, saddr,
1237 true);
1238 iphc1 |= LOWPAN_IPHC_SAC;
1239 } else {
1240 if (ipv6_saddr_type & IPV6_ADDR_LINKLOCAL &&
1241 lowpan_is_linklocal_zero_padded(hdr->saddr)) {
1242 iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
1243 &hdr->saddr,
1244 saddr, true);
1245 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
1246 &hdr->saddr, iphc1);
1247 } else {
1248 pr_debug("send the full source address\n");
1249 lowpan_push_hc_data(&hc_ptr,
1250 hdr->saddr.s6_addr, 16);
1251 }
1252 }
1253 }
1254
1255 /* destination address compression */
1256 if (ipv6_daddr_type & IPV6_ADDR_MULTICAST) {
1257 pr_debug("destination address is multicast: ");
1258 iphc1 |= LOWPAN_IPHC_M;
1259 if (dci) {
1260 iphc1 |= lowpan_iphc_mcast_ctx_addr_compress(&hc_ptr,
1261 &dci_entry,
1262 &hdr->daddr);
1263 iphc1 |= LOWPAN_IPHC_DAC;
1264 } else {
1265 iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr,
1266 &hdr->daddr);
1267 }
1268 } else {
1269 if (dci) {
1270 iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
1271 &hdr->daddr,
1272 &dci_entry, daddr,
1273 false);
1274 iphc1 |= LOWPAN_IPHC_DAC;
1275 } else {
1276 if (ipv6_daddr_type & IPV6_ADDR_LINKLOCAL &&
1277 lowpan_is_linklocal_zero_padded(hdr->daddr)) {
1278 iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
1279 &hdr->daddr,
1280 daddr, false);
1281 pr_debug("dest address unicast link-local %pI6c iphc1 0x%02x\n",
1282 &hdr->daddr, iphc1);
1283 } else {
1284 pr_debug("dest address unicast %pI6c\n",
1285 &hdr->daddr);
1286 lowpan_push_hc_data(&hc_ptr,
1287 hdr->daddr.s6_addr, 16);
1288 }
1289 }
1290 }
1291
1292 /* next header compression */
1293 if (iphc0 & LOWPAN_IPHC_NH) {
1294 ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
1295 if (ret < 0)
1296 return ret;
1297 }
1298
1299 head[0] = iphc0;
1300 head[1] = iphc1;
1301
1302 skb_pull(skb, sizeof(struct ipv6hdr));
1303 skb_reset_transport_header(skb);
1304 memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
1305 skb_reset_network_header(skb);
1306
1307 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
1308
1309 raw_dump_table(__func__, "raw skb data dump compressed",
1310 skb->data, skb->len);
1311 return 0;
1312 }
1313 EXPORT_SYMBOL_GPL(lowpan_header_compress);
Linux with added FPC-III support