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Merge tag 'mips_4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/mips
[linux.git] / net / 6lowpan / iphc.c
CommitLineData
8df8c56a
JR		 1/*
2 * Copyright 2011, Siemens AG
3 * written by Alexander Smirnov <[email protected]>
4 */
5
4710d806 6/* Based on patches from Jon Smirl <[email protected]>
8df8c56a
JR		 7 * Copyright (c) 2011 Jon Smirl <[email protected]>
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 *
8df8c56a
JR		 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>
8911d774 52
cefc8c8a 53#include <net/6lowpan.h>
8df8c56a 54#include <net/ipv6.h>
8911d774 55
5609c185 56#include "6lowpan_i.h"
cc6ed268
AA		 57#include "nhc.h"
58
c8a3e7eb
AA		 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
6350047e 67
c8a3e7eb
AA		 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
6350047e
AA		 73
74/* Values of fields within the IPHC encoding second byte */
75#define LOWPAN_IPHC_CID 0x80
76
6350047e 77#define LOWPAN_IPHC_SAC 0x40
6350047e 78
c8a3e7eb
AA		 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
6350047e
AA		 84
85#define LOWPAN_IPHC_M 0x08
c8a3e7eb 86
6350047e 87#define LOWPAN_IPHC_DAC 0x04
c8a3e7eb
AA		 88
89#define LOWPAN_IPHC_DAM_MASK 0x03
6350047e
AA		 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
6350047e
AA		 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
feb2add3
AA		 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
5609c185
AA		 153#define LOWPAN_IPHC_CID_DCI(cid) (cid & 0x0f)
154#define LOWPAN_IPHC_CID_SCI(cid) ((cid & 0xf0) >> 4)
155
7115a968
AA		 156static inline void
157lowpan_iphc_uncompress_802154_lladdr(struct in6_addr *ipaddr,
158 const void *lladdr)
8911d774
AA		 159{
160 const struct ieee802154_addr *addr = lladdr;
2bc068c3 161 u8 eui64[EUI64_ADDR_LEN];
8911d774
AA		 162
163 switch (addr->mode) {
164 case IEEE802154_ADDR_LONG:
165 ieee802154_le64_to_be64(eui64, &addr->extended_addr);
7115a968 166 lowpan_iphc_uncompress_eui64_lladdr(ipaddr, eui64);
8911d774
AA		 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
5609c185
AA		 189static struct lowpan_iphc_ctx *
190lowpan_iphc_ctx_get_by_id(const struct net_device *dev, u8 id)
191{
2e4d60cb 192 struct lowpan_iphc_ctx *ret = &lowpan_dev(dev)->ctx.table[id];
5609c185
AA		 193
194 if (!lowpan_iphc_ctx_is_active(ret))
195 return NULL;
196
197 return ret;
198}
199
200static struct lowpan_iphc_ctx *
201lowpan_iphc_ctx_get_by_addr(const struct net_device *dev,
202 const struct in6_addr *addr)
203{
2e4d60cb 204 struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
5609c185
AA		 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
244static struct lowpan_iphc_ctx *
245lowpan_iphc_ctx_get_by_mcast_addr(const struct net_device *dev,
246 const struct in6_addr *addr)
247{
2e4d60cb 248 struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
5609c185
AA		 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
fa09ae66
LAD		 281static 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
4710d806 298/* Uncompress address function for source and
8df8c56a
JR		 299 * destination address(non-multicast).
300 *
c8a3e7eb 301 * address_mode is the masked value for sam or dam value
8df8c56a 302 */
7115a968
AA		 303static 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)
8df8c56a
JR		 307{
308 bool fail;
309
310 switch (address_mode) {
c8a3e7eb
AA		 311 /* SAM and DAM are the same here */
312 case LOWPAN_IPHC_DAM_00:
8df8c56a
JR		 313 /* for global link addresses */
314 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
315 break;
c8a3e7eb
AA		 316 case LOWPAN_IPHC_SAM_01:
317 case LOWPAN_IPHC_DAM_01:
8df8c56a
JR		 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;
c8a3e7eb
AA		 323 case LOWPAN_IPHC_SAM_10:
324 case LOWPAN_IPHC_DAM_10:
8df8c56a
JR		 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;
c8a3e7eb
AA		 332 case LOWPAN_IPHC_SAM_11:
333 case LOWPAN_IPHC_DAM_11:
8df8c56a 334 fail = false;
2e4d60cb 335 switch (lowpan_dev(dev)->lltype) {
8911d774 336 case LOWPAN_LLTYPE_IEEE802154:
7115a968 337 lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
8df8c56a
JR		 338 break;
339 default:
fa09ae66 340 lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
8911d774 341 break;
8df8c56a
JR		 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
4710d806 360/* Uncompress address function for source context
8df8c56a
JR		 361 * based address(non-multicast).
362 */
7115a968
AA		 363static 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)
8df8c56a 368{
5609c185
AA		 369 bool fail;
370
c8a3e7eb 371 switch (address_mode) {
5609c185
AA		 372 /* SAM and DAM are the same here */
373 case LOWPAN_IPHC_DAM_00:
374 fail = false;
375 /* SAM_00 -> unspec address ::
8df8c56a 376 * Do nothing, address is already ::
5609c185
AA		 377 *
378 * DAM 00 -> reserved should never occur.
8df8c56a
JR		 379 */
380 break;
c8a3e7eb 381 case LOWPAN_IPHC_SAM_01:
5609c185
AA		 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;
c8a3e7eb 386 case LOWPAN_IPHC_SAM_10:
5609c185
AA		 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;
c8a3e7eb 393 case LOWPAN_IPHC_SAM_11:
5609c185
AA		 394 case LOWPAN_IPHC_DAM_11:
395 fail = false;
2e4d60cb 396 switch (lowpan_dev(dev)->lltype) {
5609c185 397 case LOWPAN_LLTYPE_IEEE802154:
7115a968 398 lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
5609c185
AA		 399 break;
400 default:
fa09ae66 401 lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
5609c185
AA		 402 break;
403 }
404 ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
405 break;
8df8c56a 406 default:
c8a3e7eb 407 pr_debug("Invalid sam value: 0x%x\n", address_mode);
8df8c56a
JR		 408 return -EINVAL;
409 }
410
5609c185
AA		 411 if (fail) {
412 pr_debug("Failed to fetch skb data\n");
413 return -EIO;
414 }
415
8df8c56a
JR		 416 raw_dump_inline(NULL,
417 "Reconstructed context based ipv6 src addr is",
418 ipaddr->s6_addr, 16);
419
420 return 0;
421}
422
8df8c56a
JR		 423/* Uncompress function for multicast destination address,
424 * when M bit is set.
425 */
7fc4cfda
MH		 426static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
427 struct in6_addr *ipaddr,
c8a3e7eb 428 u8 address_mode)
8df8c56a
JR		 429{
430 bool fail;
431
c8a3e7eb 432 switch (address_mode) {
8df8c56a
JR		 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:
c8a3e7eb 464 pr_debug("DAM value has a wrong value: 0x%x\n", address_mode);
8df8c56a
JR		 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",
7fc4cfda 474 ipaddr->s6_addr, 16);
8df8c56a
JR		 475
476 return 0;
477}
478
5609c185
AA		 479static 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);
4c23d874 490 if (fail)
5609c185
AA		 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
b5af9bdb
AA		 503/* get the ecn values from iphc tf format and set it to ipv6hdr */
504static 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 */
514static 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 */
526static 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 */
545static 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
8df8c56a 605/* TTL uncompression values */
c8a3e7eb
AA		 606static const u8 lowpan_ttl_values[] = {
607 [LOWPAN_IPHC_HLIM_01] = 1,
608 [LOWPAN_IPHC_HLIM_10] = 64,
609 [LOWPAN_IPHC_HLIM_11] = 255,
610};
8df8c56a 611
8911d774
AA		 612int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
613 const void *daddr, const void *saddr)
8df8c56a
JR		 614{
615 struct ipv6hdr hdr = {};
5609c185
AA		 616 struct lowpan_iphc_ctx *ci;
617 u8 iphc0, iphc1, cid = 0;
8df8c56a
JR		 618 int err;
619
620 raw_dump_table(__func__, "raw skb data dump uncompressed",
4710d806 621 skb->data, skb->len);
8df8c56a 622
478208e3
AA		 623 if (lowpan_fetch_skb(skb, &iphc0, sizeof(iphc0)) ||
624 lowpan_fetch_skb(skb, &iphc1, sizeof(iphc1)))
8911d774
AA		 625 return -EINVAL;
626
8df8c56a
JR		 627 hdr.version = 6;
628
5609c185
AA		 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
b5af9bdb
AA		 635 err = lowpan_iphc_tf_decompress(skb, &hdr,
636 iphc0 & LOWPAN_IPHC_TF_MASK);
637 if (err < 0)
638 return err;
8df8c56a
JR		 639
640 /* Next Header */
c8a3e7eb 641 if (!(iphc0 & LOWPAN_IPHC_NH)) {
8df8c56a 642 /* Next header is carried inline */
4ebc960f 643 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
56b2c3ee 644 return -EINVAL;
8df8c56a
JR		 645
646 pr_debug("NH flag is set, next header carried inline: %02x\n",
647 hdr.nexthdr);
648 }
649
650 /* Hop Limit */
c8a3e7eb
AA		 651 if ((iphc0 & LOWPAN_IPHC_HLIM_MASK) != LOWPAN_IPHC_HLIM_00) {
652 hdr.hop_limit = lowpan_ttl_values[iphc0 & LOWPAN_IPHC_HLIM_MASK];
4710d806 653 } else {
4ebc960f
AA		 654 if (lowpan_fetch_skb(skb, &hdr.hop_limit,
655 sizeof(hdr.hop_limit)))
56b2c3ee 656 return -EINVAL;
8df8c56a
JR		 657 }
658
8df8c56a 659 if (iphc1 & LOWPAN_IPHC_SAC) {
2e4d60cb 660 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 661 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_SCI(cid));
662 if (!ci) {
2e4d60cb 663 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 664 return -EINVAL;
665 }
666
8df8c56a 667 pr_debug("SAC bit is set. Handle context based source address.\n");
7115a968
AA		 668 err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.saddr,
669 iphc1 & LOWPAN_IPHC_SAM_MASK,
670 saddr);
2e4d60cb 671 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
8df8c56a
JR		 672 } else {
673 /* Source address uncompression */
674 pr_debug("source address stateless compression\n");
7115a968
AA		 675 err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.saddr,
676 iphc1 & LOWPAN_IPHC_SAM_MASK,
677 saddr);
8df8c56a
JR		 678 }
679
680 /* Check on error of previous branch */
681 if (err)
56b2c3ee 682 return -EINVAL;
8df8c56a 683
5609c185
AA		 684 switch (iphc1 & (LOWPAN_IPHC_M | LOWPAN_IPHC_DAC)) {
685 case LOWPAN_IPHC_M | LOWPAN_IPHC_DAC:
94e4a680
AA		 686 skb->pkt_type = PACKET_BROADCAST;
687
2e4d60cb 688 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 689 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
690 if (!ci) {
2e4d60cb 691 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 692 return -EINVAL;
693 }
7fc4cfda 694
5609c185
AA		 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);
2e4d60cb 700 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 701 break;
702 case LOWPAN_IPHC_M:
94e4a680
AA		 703 skb->pkt_type = PACKET_BROADCAST;
704
5609c185
AA		 705 /* multicast */
706 err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
707 iphc1 & LOWPAN_IPHC_DAM_MASK);
708 break;
709 case LOWPAN_IPHC_DAC:
94e4a680
AA		 710 skb->pkt_type = PACKET_HOST;
711
2e4d60cb 712 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 713 ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
714 if (!ci) {
2e4d60cb 715 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185 716 return -EINVAL;
8df8c56a 717 }
5609c185
AA		 718
719 /* Destination address context based uncompression */
720 pr_debug("DAC bit is set. Handle context based destination address.\n");
7115a968
AA		 721 err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.daddr,
722 iphc1 & LOWPAN_IPHC_DAM_MASK,
723 daddr);
2e4d60cb 724 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 725 break;
726 default:
94e4a680
AA		 727 skb->pkt_type = PACKET_HOST;
728
7115a968
AA		 729 err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.daddr,
730 iphc1 & LOWPAN_IPHC_DAM_MASK,
731 daddr);
8df8c56a 732 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
c8a3e7eb 733 iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
5609c185 734 break;
8df8c56a
JR		 735 }
736
5609c185
AA		 737 if (err)
738 return -EINVAL;
739
cc6ed268 740 /* Next header data uncompression */
c8a3e7eb 741 if (iphc0 & LOWPAN_IPHC_NH) {
cc6ed268
AA		 742 err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
743 if (err < 0)
11e3ff70 744 return err;
11e3ff70
MT		 745 } else {
746 err = skb_cow(skb, sizeof(hdr));
56b2c3ee 747 if (unlikely(err))
11e3ff70 748 return err;
8df8c56a
JR		 749 }
750
2e4d60cb 751 switch (lowpan_dev(dev)->lltype) {
72a5e6bb
AA		 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 }
8df8c56a
JR		 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
f8b36176
MT		 772 skb_push(skb, sizeof(hdr));
773 skb_reset_network_header(skb);
774 skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
8df8c56a 775
f8b36176 776 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
8df8c56a 777
f8b36176 778 return 0;
8df8c56a 779}
01141234 780EXPORT_SYMBOL_GPL(lowpan_header_decompress);
8df8c56a 781
c8a3e7eb
AA		 782static const u8 lowpan_iphc_dam_to_sam_value[] = {
783 [LOWPAN_IPHC_DAM_00] = LOWPAN_IPHC_SAM_00,
784 [LOWPAN_IPHC_DAM_01] = LOWPAN_IPHC_SAM_01,
785 [LOWPAN_IPHC_DAM_10] = LOWPAN_IPHC_SAM_10,
786 [LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
787};
788
eab560e5
AA		 789static inline bool
790lowpan_iphc_compress_ctx_802154_lladdr(const struct in6_addr *ipaddr,
791 const struct lowpan_iphc_ctx *ctx,
792 const void *lladdr)
793{
794 const struct ieee802154_addr *addr = lladdr;
795 unsigned char extended_addr[EUI64_ADDR_LEN];
796 bool lladdr_compress = false;
797 struct in6_addr tmp = {};
798
799 switch (addr->mode) {
800 case IEEE802154_ADDR_LONG:
801 ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
802 /* check for SAM/DAM = 11 */
803 memcpy(&tmp.s6_addr[8], &extended_addr, EUI64_ADDR_LEN);
804 /* second bit-flip (Universe/Local) is done according RFC2464 */
805 tmp.s6_addr[8] ^= 0x02;
806 /* context information are always used */
807 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
808 if (ipv6_addr_equal(&tmp, ipaddr))
809 lladdr_compress = true;
810 break;
811 case IEEE802154_ADDR_SHORT:
812 tmp.s6_addr[11] = 0xFF;
813 tmp.s6_addr[12] = 0xFE;
814 ieee802154_le16_to_be16(&tmp.s6_addr16[7],
815 &addr->short_addr);
816 /* context information are always used */
817 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
818 if (ipv6_addr_equal(&tmp, ipaddr))
819 lladdr_compress = true;
820 break;
821 default:
822 /* should never handled and filtered by 802154 6lowpan */
823 WARN_ON_ONCE(1);
824 break;
825 }
826
827 return lladdr_compress;
828}
829
fa09ae66
LAD		 830static bool lowpan_iphc_addr_equal(const struct net_device *dev,
831 const struct lowpan_iphc_ctx *ctx,
832 const struct in6_addr *ipaddr,
833 const void *lladdr)
834{
835 struct in6_addr tmp = {};
836
837 lowpan_iphc_uncompress_lladdr(dev, &tmp, lladdr);
838
839 if (ctx)
840 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
841
842 return ipv6_addr_equal(&tmp, ipaddr);
843}
844
eab560e5
AA		 845static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
846 const struct in6_addr *ipaddr,
5609c185
AA		 847 const struct lowpan_iphc_ctx *ctx,
848 const unsigned char *lladdr, bool sam)
849{
850 struct in6_addr tmp = {};
851 u8 dam;
852
eab560e5
AA		 853 switch (lowpan_dev(dev)->lltype) {
854 case LOWPAN_LLTYPE_IEEE802154:
855 if (lowpan_iphc_compress_ctx_802154_lladdr(ipaddr, ctx,
856 lladdr)) {
857 dam = LOWPAN_IPHC_DAM_11;
858 goto out;
859 }
860 break;
861 default:
fa09ae66 862 if (lowpan_iphc_addr_equal(dev, ctx, ipaddr, lladdr)) {
eab560e5
AA		 863 dam = LOWPAN_IPHC_DAM_11;
864 goto out;
865 }
866 break;
5609c185
AA		 867 }
868
869 memset(&tmp, 0, sizeof(tmp));
24c4a81d 870 /* check for SAM/DAM = 10 */
5609c185
AA		 871 tmp.s6_addr[11] = 0xFF;
872 tmp.s6_addr[12] = 0xFE;
873 memcpy(&tmp.s6_addr[14], &ipaddr->s6_addr[14], 2);
874 /* context information are always used */
875 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
876 if (ipv6_addr_equal(&tmp, ipaddr)) {
877 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[14], 2);
878 dam = LOWPAN_IPHC_DAM_10;
879 goto out;
880 }
881
882 memset(&tmp, 0, sizeof(tmp));
24c4a81d 883 /* check for SAM/DAM = 01, should always match */
5609c185
AA		 884 memcpy(&tmp.s6_addr[8], &ipaddr->s6_addr[8], 8);
885 /* context information are always used */
886 ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
887 if (ipv6_addr_equal(&tmp, ipaddr)) {
888 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[8], 8);
889 dam = LOWPAN_IPHC_DAM_01;
890 goto out;
891 }
892
2306f656
AA		 893 WARN_ONCE(1, "context found but no address mode matched\n");
894 return LOWPAN_IPHC_DAM_00;
5609c185
AA		 895out:
896
897 if (sam)
898 return lowpan_iphc_dam_to_sam_value[dam];
899 else
900 return dam;
901}
902
eab560e5
AA		 903static inline bool
904lowpan_iphc_compress_802154_lladdr(const struct in6_addr *ipaddr,
905 const void *lladdr)
906{
907 const struct ieee802154_addr *addr = lladdr;
908 unsigned char extended_addr[EUI64_ADDR_LEN];
909 bool lladdr_compress = false;
910 struct in6_addr tmp = {};
911
912 switch (addr->mode) {
913 case IEEE802154_ADDR_LONG:
914 ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
915 if (is_addr_mac_addr_based(ipaddr, extended_addr))
916 lladdr_compress = true;
917 break;
918 case IEEE802154_ADDR_SHORT:
919 /* fe:80::ff:fe00:XXXX
920 * \__/
921 * short_addr
922 *
923 * Universe/Local bit is zero.
924 */
925 tmp.s6_addr[0] = 0xFE;
926 tmp.s6_addr[1] = 0x80;
927 tmp.s6_addr[11] = 0xFF;
928 tmp.s6_addr[12] = 0xFE;
929 ieee802154_le16_to_be16(&tmp.s6_addr16[7],
930 &addr->short_addr);
931 if (ipv6_addr_equal(&tmp, ipaddr))
932 lladdr_compress = true;
933 break;
934 default:
935 /* should never handled and filtered by 802154 6lowpan */
936 WARN_ON_ONCE(1);
937 break;
938 }
939
940 return lladdr_compress;
941}
942
943static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct net_device *dev,
944 const struct in6_addr *ipaddr,
c8a3e7eb 945 const unsigned char *lladdr, bool sam)
8df8c56a 946{
eab560e5 947 u8 dam = LOWPAN_IPHC_DAM_01;
8df8c56a 948
eab560e5
AA		 949 switch (lowpan_dev(dev)->lltype) {
950 case LOWPAN_LLTYPE_IEEE802154:
951 if (lowpan_iphc_compress_802154_lladdr(ipaddr, lladdr)) {
952 dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
953 pr_debug("address compression 0 bits\n");
954 goto out;
955 }
956 break;
957 default:
fa09ae66
LAD		 958 if (lowpan_iphc_addr_equal(dev, NULL, ipaddr, lladdr)) {
959 dam = LOWPAN_IPHC_DAM_11;
eab560e5
AA		 960 pr_debug("address compression 0 bits\n");
961 goto out;
962 }
fa09ae66 963
eab560e5
AA		 964 break;
965 }
966
967 if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
8df8c56a 968 /* compress IID to 16 bits xxxx::XXXX */
85c71240 969 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
c8a3e7eb 970 dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
8df8c56a 971 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
84ca5e03 972 *hc_ptr - 2, 2);
eab560e5 973 goto out;
8df8c56a
JR		 974 }
975
eab560e5
AA		 976 /* do not compress IID => xxxx::IID */
977 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
978 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
979 *hc_ptr - 8, 8);
980
981out:
982
c8a3e7eb
AA		 983 if (sam)
984 return lowpan_iphc_dam_to_sam_value[dam];
985 else
986 return dam;
8df8c56a
JR		 987}
988
b5af9bdb
AA		 989/* lowpan_iphc_get_tc - get the ECN + DCSP fields in hc format */
990static inline u8 lowpan_iphc_get_tc(const struct ipv6hdr *hdr)
991{
992 u8 dscp, ecn;
993
994 /* hdr->priority contains the higher bits of dscp, lower are part of
995 * flow_lbl[0]. Note ECN, DCSP is swapped in ipv6 hdr.
996 */
997 dscp = (hdr->priority << 2) | ((hdr->flow_lbl[0] & 0xc0) >> 6);
998 /* ECN is at the two lower bits from first nibble of flow_lbl[0] */
999 ecn = (hdr->flow_lbl[0] & 0x30);
1000 /* for pretty debug output, also shift ecn to get the ecn value */
1001 pr_debug("ecn 0x%02x dscp 0x%02x\n", ecn >> 4, dscp);
1002 /* ECN is at 0x30 now, shift it to have ECN + DCSP */
1003 return (ecn << 2) | dscp;
1004}
1005
1006/* lowpan_iphc_is_flow_lbl_zero - check if flow label is zero */
1007static inline bool lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr *hdr)
1008{
1009 return ((!(hdr->flow_lbl[0] & 0x0f)) &&
1010 !hdr->flow_lbl[1] && !hdr->flow_lbl[2]);
1011}
1012
1013/* lowpan_iphc_tf_compress - compress the traffic class which is set by
1014 * ipv6hdr. Return the corresponding format identifier which is used.
1015 */
1016static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
1017{
1018 /* get ecn dscp data in a byteformat as: ECN(hi) + DSCP(lo) */
1019 u8 tc = lowpan_iphc_get_tc(hdr), tf[4], val;
1020
1021 /* printout the traffic class in hc format */
1022 pr_debug("tc 0x%02x\n", tc);
1023
1024 if (lowpan_iphc_is_flow_lbl_zero(hdr)) {
1025 if (!tc) {
1026 /* 11: Traffic Class and Flow Label are elided. */
1027 val = LOWPAN_IPHC_TF_11;
1028 } else {
1029 /* 10: ECN + DSCP (1 byte), Flow Label is elided.
1030 *
1031 * 0 1 2 3 4 5 6 7
1032 * +-+-+-+-+-+-+-+-+
1033 * |ECN| DSCP |
1034 * +-+-+-+-+-+-+-+-+
1035 */
1036 lowpan_push_hc_data(hc_ptr, &tc, sizeof(tc));
1037 val = LOWPAN_IPHC_TF_10;
1038 }
1039 } else {
1040 /* check if dscp is zero, it's after the first two bit */
1041 if (!(tc & 0x3f)) {
1042 /* 01: ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
1043 *
1044 * 1 2
1045 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
1046 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1047 * |ECN|rsv| Flow Label |
1048 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1049 */
1050 memcpy(&tf[0], &hdr->flow_lbl[0], 3);
1051 /* zero the highest 4-bits, contains DCSP + ECN */
1052 tf[0] &= ~0xf0;
1053 /* set ECN */
1054 tf[0] |= (tc & 0xc0);
1055
1056 lowpan_push_hc_data(hc_ptr, tf, 3);
1057 val = LOWPAN_IPHC_TF_01;
1058 } else {
1059 /* 00: ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
1060 *
1061 * 1 2 3
1062 * 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
1063 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1064 * |ECN| DSCP | rsv | Flow Label |
1065 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1066 */
1067 memcpy(&tf[0], &tc, sizeof(tc));
1068 /* highest nibble of flow_lbl[0] is part of DSCP + ECN
1069 * which will be the 4-bit pad and will be filled with
1070 * zeros afterwards.
1071 */
1072 memcpy(&tf[1], &hdr->flow_lbl[0], 3);
1073 /* zero the 4-bit pad, which is reserved */
1074 tf[1] &= ~0xf0;
1075
1076 lowpan_push_hc_data(hc_ptr, tf, 4);
1077 val = LOWPAN_IPHC_TF_00;
1078 }
1079 }
1080
1081 return val;
1082}
1083
5609c185
AA		 1084static u8 lowpan_iphc_mcast_ctx_addr_compress(u8 **hc_ptr,
1085 const struct lowpan_iphc_ctx *ctx,
1086 const struct in6_addr *ipaddr)
1087{
1088 u8 data[6];
1089
1090 /* flags/scope, reserved (RIID) */
1091 memcpy(data, &ipaddr->s6_addr[1], 2);
1092 /* group ID */
1093 memcpy(&data[1], &ipaddr->s6_addr[11], 4);
1094 lowpan_push_hc_data(hc_ptr, data, 6);
1095
1096 return LOWPAN_IPHC_DAM_00;
1097}
1098
09bf420f
AA		 1099static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
1100 const struct in6_addr *ipaddr)
1101{
1102 u8 val;
1103
1104 if (lowpan_is_mcast_addr_compressable8(ipaddr)) {
1105 pr_debug("compressed to 1 octet\n");
1106 /* use last byte */
1107 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[15], 1);
1108 val = LOWPAN_IPHC_DAM_11;
1109 } else if (lowpan_is_mcast_addr_compressable32(ipaddr)) {
1110 pr_debug("compressed to 4 octets\n");
1111 /* second byte + the last three */
1112 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
1113 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[13], 3);
1114 val = LOWPAN_IPHC_DAM_10;
1115 } else if (lowpan_is_mcast_addr_compressable48(ipaddr)) {
1116 pr_debug("compressed to 6 octets\n");
1117 /* second byte + the last five */
1118 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
1119 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[11], 5);
1120 val = LOWPAN_IPHC_DAM_01;
1121 } else {
1122 pr_debug("using full address\n");
1123 lowpan_push_hc_data(hc_ptr, ipaddr->s6_addr, 16);
1124 val = LOWPAN_IPHC_DAM_00;
1125 }
1126
1127 return val;
1128}
1129
a6f77389
AA		 1130int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
1131 const void *daddr, const void *saddr)
8df8c56a 1132{
5609c185 1133 u8 iphc0, iphc1, *hc_ptr, cid = 0;
8df8c56a 1134 struct ipv6hdr *hdr;
bf513fd6 1135 u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
5609c185
AA		 1136 struct lowpan_iphc_ctx *dci, *sci, dci_entry, sci_entry;
1137 int ret, ipv6_daddr_type, ipv6_saddr_type;
8df8c56a 1138
a6f77389 1139 if (skb->protocol != htons(ETH_P_IPV6))
8df8c56a
JR		 1140 return -EINVAL;
1141
1142 hdr = ipv6_hdr(skb);
84ca5e03 1143 hc_ptr = head + 2;
8df8c56a
JR		 1144
1145 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
1146 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
4710d806
VB		 1147 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
1148 hdr->hop_limit, &hdr->daddr);
8df8c56a
JR		 1149
1150 raw_dump_table(__func__, "raw skb network header dump",
4710d806 1151 skb_network_header(skb), sizeof(struct ipv6hdr));
8df8c56a 1152
4710d806 1153 /* As we copy some bit-length fields, in the IPHC encoding bytes,
8df8c56a
JR		 1154 * we sometimes use |=
1155 * If the field is 0, and the current bit value in memory is 1,
1156 * this does not work. We therefore reset the IPHC encoding here
1157 */
1158 iphc0 = LOWPAN_DISPATCH_IPHC;
1159 iphc1 = 0;
1160
7fc4cfda 1161 raw_dump_table(__func__, "sending raw skb network uncompressed packet",
4710d806 1162 skb->data, skb->len);
8df8c56a 1163
5609c185 1164 ipv6_daddr_type = ipv6_addr_type(&hdr->daddr);
2e4d60cb 1165 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 1166 if (ipv6_daddr_type & IPV6_ADDR_MULTICAST)
1167 dci = lowpan_iphc_ctx_get_by_mcast_addr(dev, &hdr->daddr);
1168 else
1169 dci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->daddr);
1170 if (dci) {
1171 memcpy(&dci_entry, dci, sizeof(*dci));
1172 cid |= dci->id;
1173 }
2e4d60cb 1174 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185 1175
2e4d60cb 1176 spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 1177 sci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->saddr);
1178 if (sci) {
1179 memcpy(&sci_entry, sci, sizeof(*sci));
1180 cid |= (sci->id << 4);
1181 }
2e4d60cb 1182 spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
5609c185
AA		 1183
1184 /* if cid is zero it will be compressed */
1185 if (cid) {
1186 iphc1 |= LOWPAN_IPHC_CID;
1187 lowpan_push_hc_data(&hc_ptr, &cid, sizeof(cid));
1188 }
1189
b5af9bdb
AA		 1190 /* Traffic Class, Flow Label compression */
1191 iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
8df8c56a
JR		 1192
1193 /* NOTE: payload length is always compressed */
1194
cc6ed268
AA		 1195 /* Check if we provide the nhc format for nexthdr and compression
1196 * functionality. If not nexthdr is handled inline and not compressed.
1197 */
607b0bd3
AA		 1198 ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr);
1199 if (ret == -ENOENT)
1200 lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
1201 sizeof(hdr->nexthdr));
1202 else
c8a3e7eb 1203 iphc0 |= LOWPAN_IPHC_NH;
8df8c56a 1204
4710d806 1205 /* Hop limit
8df8c56a
JR		 1206 * if 1: compress, encoding is 01
1207 * if 64: compress, encoding is 10
1208 * if 255: compress, encoding is 11
1209 * else do not compress
1210 */
1211 switch (hdr->hop_limit) {
1212 case 1:
c8a3e7eb 1213 iphc0 |= LOWPAN_IPHC_HLIM_01;
8df8c56a
JR		 1214 break;
1215 case 64:
c8a3e7eb 1216 iphc0 |= LOWPAN_IPHC_HLIM_10;
8df8c56a
JR		 1217 break;
1218 case 255:
c8a3e7eb 1219 iphc0 |= LOWPAN_IPHC_HLIM_11;
8df8c56a
JR		 1220 break;
1221 default:
85c71240
AA		 1222 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
1223 sizeof(hdr->hop_limit));
8df8c56a
JR		 1224 }
1225
5609c185 1226 ipv6_saddr_type = ipv6_addr_type(&hdr->saddr);
8df8c56a 1227 /* source address compression */
5609c185 1228 if (ipv6_saddr_type == IPV6_ADDR_ANY) {
8df8c56a
JR		 1229 pr_debug("source address is unspecified, setting SAC\n");
1230 iphc1 |= LOWPAN_IPHC_SAC;
8df8c56a 1231 } else {
5609c185 1232 if (sci) {
eab560e5
AA		 1233 iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
1234 &hdr->saddr,
5609c185
AA		 1235 &sci_entry, saddr,
1236 true);
1237 iphc1 |= LOWPAN_IPHC_SAC;
556a5bfc 1238 } else {
feb2add3
AA		 1239 if (ipv6_saddr_type & IPV6_ADDR_LINKLOCAL &&
1240 lowpan_is_linklocal_zero_padded(hdr->saddr)) {
eab560e5 1241 iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
5609c185
AA		 1242 &hdr->saddr,
1243 saddr, true);
1244 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
1245 &hdr->saddr, iphc1);
1246 } else {
1247 pr_debug("send the full source address\n");
1248 lowpan_push_hc_data(&hc_ptr,
1249 hdr->saddr.s6_addr, 16);
1250 }
556a5bfc 1251 }
8df8c56a
JR		 1252 }
1253
1254 /* destination address compression */
5609c185 1255 if (ipv6_daddr_type & IPV6_ADDR_MULTICAST) {
8df8c56a 1256 pr_debug("destination address is multicast: ");
8790404d 1257 iphc1 |= LOWPAN_IPHC_M;
5609c185
AA		 1258 if (dci) {
1259 iphc1 |= lowpan_iphc_mcast_ctx_addr_compress(&hc_ptr,
1260 &dci_entry,
1261 &hdr->daddr);
8790404d 1262 iphc1 |= LOWPAN_IPHC_DAC;
5609c185 1263 } else {
5609c185
AA		 1264 iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr,
1265 &hdr->daddr);
1266 }
8df8c56a 1267 } else {
5609c185 1268 if (dci) {
eab560e5
AA		 1269 iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
1270 &hdr->daddr,
5609c185
AA		 1271 &dci_entry, daddr,
1272 false);
1273 iphc1 |= LOWPAN_IPHC_DAC;
8df8c56a 1274 } else {
feb2add3
AA		 1275 if (ipv6_daddr_type & IPV6_ADDR_LINKLOCAL &&
1276 lowpan_is_linklocal_zero_padded(hdr->daddr)) {
eab560e5 1277 iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
5609c185
AA		 1278 &hdr->daddr,
1279 daddr, false);
1280 pr_debug("dest address unicast link-local %pI6c iphc1 0x%02x\n",
1281 &hdr->daddr, iphc1);
1282 } else {
1283 pr_debug("dest address unicast %pI6c\n",
1284 &hdr->daddr);
1285 lowpan_push_hc_data(&hc_ptr,
1286 hdr->daddr.s6_addr, 16);
1287 }
8df8c56a
JR		 1288 }
1289 }
1290
cc6ed268 1291 /* next header compression */
c8a3e7eb 1292 if (iphc0 & LOWPAN_IPHC_NH) {
cc6ed268
AA		 1293 ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
1294 if (ret < 0)
1295 return ret;
1296 }
8df8c56a
JR		 1297
1298 head[0] = iphc0;
1299 head[1] = iphc1;
1300
1301 skb_pull(skb, sizeof(struct ipv6hdr));
1302 skb_reset_transport_header(skb);
84ca5e03 1303 memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
8df8c56a
JR		 1304 skb_reset_network_header(skb);
1305
84ca5e03 1306 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
8df8c56a
JR		 1307
1308 raw_dump_table(__func__, "raw skb data dump compressed",
4710d806 1309 skb->data, skb->len);
8df8c56a
JR		 1310 return 0;
1311}
1312EXPORT_SYMBOL_GPL(lowpan_header_compress);
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