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 /* special link-layer handling */
57 #include <net/mac802154.h>
58
59 #include "nhc.h"
60
61 /* Values of fields within the IPHC encoding first byte */
62 #define LOWPAN_IPHC_TF_MASK 0x18
63 #define LOWPAN_IPHC_TF_00 0x00
64 #define LOWPAN_IPHC_TF_01 0x08
65 #define LOWPAN_IPHC_TF_10 0x10
66 #define LOWPAN_IPHC_TF_11 0x18
67
68 #define LOWPAN_IPHC_NH 0x04
69
70 #define LOWPAN_IPHC_HLIM_MASK 0x03
71 #define LOWPAN_IPHC_HLIM_00 0x00
72 #define LOWPAN_IPHC_HLIM_01 0x01
73 #define LOWPAN_IPHC_HLIM_10 0x02
74 #define LOWPAN_IPHC_HLIM_11 0x03
75
76 /* Values of fields within the IPHC encoding second byte */
77 #define LOWPAN_IPHC_CID 0x80
78
79 #define LOWPAN_IPHC_SAC 0x40
80
81 #define LOWPAN_IPHC_SAM_MASK 0x30
82 #define LOWPAN_IPHC_SAM_00 0x00
83 #define LOWPAN_IPHC_SAM_01 0x10
84 #define LOWPAN_IPHC_SAM_10 0x20
85 #define LOWPAN_IPHC_SAM_11 0x30
86
87 #define LOWPAN_IPHC_M 0x08
88
89 #define LOWPAN_IPHC_DAC 0x04
90
91 #define LOWPAN_IPHC_DAM_MASK 0x03
92 #define LOWPAN_IPHC_DAM_00 0x00
93 #define LOWPAN_IPHC_DAM_01 0x01
94 #define LOWPAN_IPHC_DAM_10 0x02
95 #define LOWPAN_IPHC_DAM_11 0x03
96
97 /* ipv6 address based on mac
98 * second bit-flip (Universe/Local) is done according RFC2464
99 */
100 #define is_addr_mac_addr_based(a, m) \
101 ((((a)->s6_addr[8]) == (((m)[0]) ^ 0x02)) && \
102 (((a)->s6_addr[9]) == (m)[1]) && \
103 (((a)->s6_addr[10]) == (m)[2]) && \
104 (((a)->s6_addr[11]) == (m)[3]) && \
105 (((a)->s6_addr[12]) == (m)[4]) && \
106 (((a)->s6_addr[13]) == (m)[5]) && \
107 (((a)->s6_addr[14]) == (m)[6]) && \
108 (((a)->s6_addr[15]) == (m)[7]))
109
110 /* check whether we can compress the IID to 16 bits,
111 * it's possible for unicast addresses with first 49 bits are zero only.
112 */
113 #define lowpan_is_iid_16_bit_compressable(a) \
114 ((((a)->s6_addr16[4]) == 0) && \
115 (((a)->s6_addr[10]) == 0) && \
116 (((a)->s6_addr[11]) == 0xff) && \
117 (((a)->s6_addr[12]) == 0xfe) && \
118 (((a)->s6_addr[13]) == 0))
119
120 /* check whether the 112-bit gid of the multicast address is mappable to: */
121
122 /* 48 bits, FFXX::00XX:XXXX:XXXX */
123 #define lowpan_is_mcast_addr_compressable48(a) \
124 ((((a)->s6_addr16[1]) == 0) && \
125 (((a)->s6_addr16[2]) == 0) && \
126 (((a)->s6_addr16[3]) == 0) && \
127 (((a)->s6_addr16[4]) == 0) && \
128 (((a)->s6_addr[10]) == 0))
129
130 /* 32 bits, FFXX::00XX:XXXX */
131 #define lowpan_is_mcast_addr_compressable32(a) \
132 ((((a)->s6_addr16[1]) == 0) && \
133 (((a)->s6_addr16[2]) == 0) && \
134 (((a)->s6_addr16[3]) == 0) && \
135 (((a)->s6_addr16[4]) == 0) && \
136 (((a)->s6_addr16[5]) == 0) && \
137 (((a)->s6_addr[12]) == 0))
138
139 /* 8 bits, FF02::00XX */
140 #define lowpan_is_mcast_addr_compressable8(a) \
141 ((((a)->s6_addr[1]) == 2) && \
142 (((a)->s6_addr16[1]) == 0) && \
143 (((a)->s6_addr16[2]) == 0) && \
144 (((a)->s6_addr16[3]) == 0) && \
145 (((a)->s6_addr16[4]) == 0) && \
146 (((a)->s6_addr16[5]) == 0) && \
147 (((a)->s6_addr16[6]) == 0) && \
148 (((a)->s6_addr[14]) == 0))
149
iphc_uncompress_eui64_lladdr(struct in6_addr * ipaddr,const void * lladdr)150 static inline void iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
151 const void *lladdr)
152 {
153 /* fe:80::XXXX:XXXX:XXXX:XXXX
154 * \_________________/
155 * hwaddr
156 */
157 ipaddr->s6_addr[0] = 0xFE;
158 ipaddr->s6_addr[1] = 0x80;
159 memcpy(&ipaddr->s6_addr[8], lladdr, EUI64_ADDR_LEN);
160 /* second bit-flip (Universe/Local)
161 * is done according RFC2464
162 */
163 ipaddr->s6_addr[8] ^= 0x02;
164 }
165
iphc_uncompress_802154_lladdr(struct in6_addr * ipaddr,const void * lladdr)166 static inline void iphc_uncompress_802154_lladdr(struct in6_addr *ipaddr,
167 const void *lladdr)
168 {
169 const struct ieee802154_addr *addr = lladdr;
170 u8 eui64[EUI64_ADDR_LEN] = { };
171
172 switch (addr->mode) {
173 case IEEE802154_ADDR_LONG:
174 ieee802154_le64_to_be64(eui64, &addr->extended_addr);
175 iphc_uncompress_eui64_lladdr(ipaddr, eui64);
176 break;
177 case IEEE802154_ADDR_SHORT:
178 /* fe:80::ff:fe00:XXXX
179 * \__/
180 * short_addr
181 *
182 * Universe/Local bit is zero.
183 */
184 ipaddr->s6_addr[0] = 0xFE;
185 ipaddr->s6_addr[1] = 0x80;
186 ipaddr->s6_addr[11] = 0xFF;
187 ipaddr->s6_addr[12] = 0xFE;
188 ieee802154_le16_to_be16(&ipaddr->s6_addr16[7],
189 &addr->short_addr);
190 break;
191 default:
192 /* should never handled and filtered by 802154 6lowpan */
193 WARN_ON_ONCE(1);
194 break;
195 }
196 }
197
198 /* Uncompress address function for source and
199 * destination address(non-multicast).
200 *
201 * address_mode is the masked value for sam or dam value
202 */
uncompress_addr(struct sk_buff * skb,const struct net_device * dev,struct in6_addr * ipaddr,u8 address_mode,const void * lladdr)203 static int uncompress_addr(struct sk_buff *skb, const struct net_device *dev,
204 struct in6_addr *ipaddr, u8 address_mode,
205 const void *lladdr)
206 {
207 bool fail;
208
209 switch (address_mode) {
210 /* SAM and DAM are the same here */
211 case LOWPAN_IPHC_DAM_00:
212 /* for global link addresses */
213 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
214 break;
215 case LOWPAN_IPHC_SAM_01:
216 case LOWPAN_IPHC_DAM_01:
217 /* fe:80::XXXX:XXXX:XXXX:XXXX */
218 ipaddr->s6_addr[0] = 0xFE;
219 ipaddr->s6_addr[1] = 0x80;
220 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
221 break;
222 case LOWPAN_IPHC_SAM_10:
223 case LOWPAN_IPHC_DAM_10:
224 /* fe:80::ff:fe00:XXXX */
225 ipaddr->s6_addr[0] = 0xFE;
226 ipaddr->s6_addr[1] = 0x80;
227 ipaddr->s6_addr[11] = 0xFF;
228 ipaddr->s6_addr[12] = 0xFE;
229 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
230 break;
231 case LOWPAN_IPHC_SAM_11:
232 case LOWPAN_IPHC_DAM_11:
233 fail = false;
234 switch (lowpan_priv(dev)->lltype) {
235 case LOWPAN_LLTYPE_IEEE802154:
236 iphc_uncompress_802154_lladdr(ipaddr, lladdr);
237 break;
238 default:
239 iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
240 break;
241 }
242 break;
243 default:
244 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
245 return -EINVAL;
246 }
247
248 if (fail) {
249 pr_debug("Failed to fetch skb data\n");
250 return -EIO;
251 }
252
253 raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
254 ipaddr->s6_addr, 16);
255
256 return 0;
257 }
258
259 /* Uncompress address function for source context
260 * based address(non-multicast).
261 */
uncompress_context_based_src_addr(struct sk_buff * skb,struct in6_addr * ipaddr,u8 address_mode)262 static int uncompress_context_based_src_addr(struct sk_buff *skb,
263 struct in6_addr *ipaddr,
264 u8 address_mode)
265 {
266 switch (address_mode) {
267 case LOWPAN_IPHC_SAM_00:
268 /* unspec address ::
269 * Do nothing, address is already ::
270 */
271 break;
272 case LOWPAN_IPHC_SAM_01:
273 /* TODO */
274 case LOWPAN_IPHC_SAM_10:
275 /* TODO */
276 case LOWPAN_IPHC_SAM_11:
277 /* TODO */
278 netdev_warn(skb->dev, "SAM value 0x%x not supported\n",
279 address_mode);
280 return -EINVAL;
281 default:
282 pr_debug("Invalid sam value: 0x%x\n", address_mode);
283 return -EINVAL;
284 }
285
286 raw_dump_inline(NULL,
287 "Reconstructed context based ipv6 src addr is",
288 ipaddr->s6_addr, 16);
289
290 return 0;
291 }
292
293 /* Uncompress function for multicast destination address,
294 * when M bit is set.
295 */
lowpan_uncompress_multicast_daddr(struct sk_buff * skb,struct in6_addr * ipaddr,u8 address_mode)296 static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
297 struct in6_addr *ipaddr,
298 u8 address_mode)
299 {
300 bool fail;
301
302 switch (address_mode) {
303 case LOWPAN_IPHC_DAM_00:
304 /* 00: 128 bits. The full address
305 * is carried in-line.
306 */
307 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
308 break;
309 case LOWPAN_IPHC_DAM_01:
310 /* 01: 48 bits. The address takes
311 * the form ffXX::00XX:XXXX:XXXX.
312 */
313 ipaddr->s6_addr[0] = 0xFF;
314 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
315 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
316 break;
317 case LOWPAN_IPHC_DAM_10:
318 /* 10: 32 bits. The address takes
319 * the form ffXX::00XX:XXXX.
320 */
321 ipaddr->s6_addr[0] = 0xFF;
322 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
323 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
324 break;
325 case LOWPAN_IPHC_DAM_11:
326 /* 11: 8 bits. The address takes
327 * the form ff02::00XX.
328 */
329 ipaddr->s6_addr[0] = 0xFF;
330 ipaddr->s6_addr[1] = 0x02;
331 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
332 break;
333 default:
334 pr_debug("DAM value has a wrong value: 0x%x\n", address_mode);
335 return -EINVAL;
336 }
337
338 if (fail) {
339 pr_debug("Failed to fetch skb data\n");
340 return -EIO;
341 }
342
343 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
344 ipaddr->s6_addr, 16);
345
346 return 0;
347 }
348
349 /* get the ecn values from iphc tf format and set it to ipv6hdr */
lowpan_iphc_tf_set_ecn(struct ipv6hdr * hdr,const u8 * tf)350 static inline void lowpan_iphc_tf_set_ecn(struct ipv6hdr *hdr, const u8 *tf)
351 {
352 /* get the two higher bits which is ecn */
353 u8 ecn = tf[0] & 0xc0;
354
355 /* ECN takes 0x30 in hdr->flow_lbl[0] */
356 hdr->flow_lbl[0] |= (ecn >> 2);
357 }
358
359 /* get the dscp values from iphc tf format and set it to ipv6hdr */
lowpan_iphc_tf_set_dscp(struct ipv6hdr * hdr,const u8 * tf)360 static inline void lowpan_iphc_tf_set_dscp(struct ipv6hdr *hdr, const u8 *tf)
361 {
362 /* DSCP is at place after ECN */
363 u8 dscp = tf[0] & 0x3f;
364
365 /* The four highest bits need to be set at hdr->priority */
366 hdr->priority |= ((dscp & 0x3c) >> 2);
367 /* The two lower bits is part of hdr->flow_lbl[0] */
368 hdr->flow_lbl[0] |= ((dscp & 0x03) << 6);
369 }
370
371 /* get the flow label values from iphc tf format and set it to ipv6hdr */
lowpan_iphc_tf_set_lbl(struct ipv6hdr * hdr,const u8 * lbl)372 static inline void lowpan_iphc_tf_set_lbl(struct ipv6hdr *hdr, const u8 *lbl)
373 {
374 /* flow label is always some array started with lower nibble of
375 * flow_lbl[0] and followed with two bytes afterwards. Inside inline
376 * data the flow_lbl position can be different, which will be handled
377 * by lbl pointer. E.g. case "01" vs "00" the traffic class is 8 bit
378 * shifted, the different lbl pointer will handle that.
379 *
380 * The flow label will started at lower nibble of flow_lbl[0], the
381 * higher nibbles are part of DSCP + ECN.
382 */
383 hdr->flow_lbl[0] |= lbl[0] & 0x0f;
384 memcpy(&hdr->flow_lbl[1], &lbl[1], 2);
385 }
386
387 /* lowpan_iphc_tf_decompress - decompress the traffic class.
388 * This function will return zero on success, a value lower than zero if
389 * failed.
390 */
lowpan_iphc_tf_decompress(struct sk_buff * skb,struct ipv6hdr * hdr,u8 val)391 static int lowpan_iphc_tf_decompress(struct sk_buff *skb, struct ipv6hdr *hdr,
392 u8 val)
393 {
394 u8 tf[4];
395
396 /* Traffic Class and Flow Label */
397 switch (val) {
398 case LOWPAN_IPHC_TF_00:
399 /* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) */
400 if (lowpan_fetch_skb(skb, tf, 4))
401 return -EINVAL;
402
403 /* 1 2 3
404 * 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
405 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
406 * |ECN| DSCP | rsv | Flow Label |
407 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
408 */
409 lowpan_iphc_tf_set_ecn(hdr, tf);
410 lowpan_iphc_tf_set_dscp(hdr, tf);
411 lowpan_iphc_tf_set_lbl(hdr, &tf[1]);
412 break;
413 case LOWPAN_IPHC_TF_01:
414 /* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided. */
415 if (lowpan_fetch_skb(skb, tf, 3))
416 return -EINVAL;
417
418 /* 1 2
419 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
420 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
421 * |ECN|rsv| Flow Label |
422 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
423 */
424 lowpan_iphc_tf_set_ecn(hdr, tf);
425 lowpan_iphc_tf_set_lbl(hdr, &tf[0]);
426 break;
427 case LOWPAN_IPHC_TF_10:
428 /* ECN + DSCP (1 byte), Flow Label is elided. */
429 if (lowpan_fetch_skb(skb, tf, 1))
430 return -EINVAL;
431
432 /* 0 1 2 3 4 5 6 7
433 * +-+-+-+-+-+-+-+-+
434 * |ECN| DSCP |
435 * +-+-+-+-+-+-+-+-+
436 */
437 lowpan_iphc_tf_set_ecn(hdr, tf);
438 lowpan_iphc_tf_set_dscp(hdr, tf);
439 break;
440 case LOWPAN_IPHC_TF_11:
441 /* Traffic Class and Flow Label are elided */
442 break;
443 default:
444 WARN_ON_ONCE(1);
445 return -EINVAL;
446 }
447
448 return 0;
449 }
450
451 /* TTL uncompression values */
452 static const u8 lowpan_ttl_values[] = {
453 [LOWPAN_IPHC_HLIM_01] = 1,
454 [LOWPAN_IPHC_HLIM_10] = 64,
455 [LOWPAN_IPHC_HLIM_11] = 255,
456 };
457
lowpan_header_decompress(struct sk_buff * skb,const struct net_device * dev,const void * daddr,const void * saddr)458 int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
459 const void *daddr, const void *saddr)
460 {
461 struct ipv6hdr hdr = {};
462 u8 iphc0, iphc1;
463 int err;
464
465 raw_dump_table(__func__, "raw skb data dump uncompressed",
466 skb->data, skb->len);
467
468 if (lowpan_fetch_skb(skb, &iphc0, sizeof(iphc0)) ||
469 lowpan_fetch_skb(skb, &iphc1, sizeof(iphc1)))
470 return -EINVAL;
471
472 /* another if the CID flag is set */
473 if (iphc1 & LOWPAN_IPHC_CID)
474 return -ENOTSUPP;
475
476 hdr.version = 6;
477
478 err = lowpan_iphc_tf_decompress(skb, &hdr,
479 iphc0 & LOWPAN_IPHC_TF_MASK);
480 if (err < 0)
481 return err;
482
483 /* Next Header */
484 if (!(iphc0 & LOWPAN_IPHC_NH)) {
485 /* Next header is carried inline */
486 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
487 return -EINVAL;
488
489 pr_debug("NH flag is set, next header carried inline: %02x\n",
490 hdr.nexthdr);
491 }
492
493 /* Hop Limit */
494 if ((iphc0 & LOWPAN_IPHC_HLIM_MASK) != LOWPAN_IPHC_HLIM_00) {
495 hdr.hop_limit = lowpan_ttl_values[iphc0 & LOWPAN_IPHC_HLIM_MASK];
496 } else {
497 if (lowpan_fetch_skb(skb, &hdr.hop_limit,
498 sizeof(hdr.hop_limit)))
499 return -EINVAL;
500 }
501
502 if (iphc1 & LOWPAN_IPHC_SAC) {
503 /* Source address context based uncompression */
504 pr_debug("SAC bit is set. Handle context based source address.\n");
505 err = uncompress_context_based_src_addr(skb, &hdr.saddr,
506 iphc1 & LOWPAN_IPHC_SAM_MASK);
507 } else {
508 /* Source address uncompression */
509 pr_debug("source address stateless compression\n");
510 err = uncompress_addr(skb, dev, &hdr.saddr,
511 iphc1 & LOWPAN_IPHC_SAM_MASK, saddr);
512 }
513
514 /* Check on error of previous branch */
515 if (err)
516 return -EINVAL;
517
518 /* check for Multicast Compression */
519 if (iphc1 & LOWPAN_IPHC_M) {
520 if (iphc1 & LOWPAN_IPHC_DAC) {
521 pr_debug("dest: context-based mcast compression\n");
522 /* TODO: implement this */
523 } else {
524 err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
525 iphc1 & LOWPAN_IPHC_DAM_MASK);
526
527 if (err)
528 return -EINVAL;
529 }
530 } else {
531 err = uncompress_addr(skb, dev, &hdr.daddr,
532 iphc1 & LOWPAN_IPHC_DAM_MASK, daddr);
533 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
534 iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
535 if (err)
536 return -EINVAL;
537 }
538
539 /* Next header data uncompression */
540 if (iphc0 & LOWPAN_IPHC_NH) {
541 err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
542 if (err < 0)
543 return err;
544 } else {
545 err = skb_cow(skb, sizeof(hdr));
546 if (unlikely(err))
547 return err;
548 }
549
550 switch (lowpan_priv(dev)->lltype) {
551 case LOWPAN_LLTYPE_IEEE802154:
552 if (lowpan_802154_cb(skb)->d_size)
553 hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
554 sizeof(struct ipv6hdr));
555 else
556 hdr.payload_len = htons(skb->len);
557 break;
558 default:
559 hdr.payload_len = htons(skb->len);
560 break;
561 }
562
563 pr_debug("skb headroom size = %d, data length = %d\n",
564 skb_headroom(skb), skb->len);
565
566 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
567 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
568 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
569 hdr.hop_limit, &hdr.daddr);
570
571 skb_push(skb, sizeof(hdr));
572 skb_reset_mac_header(skb);
573 skb_reset_network_header(skb);
574 skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
575
576 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
577
578 return 0;
579 }
580 EXPORT_SYMBOL_GPL(lowpan_header_decompress);
581
582 static const u8 lowpan_iphc_dam_to_sam_value[] = {
583 [LOWPAN_IPHC_DAM_00] = LOWPAN_IPHC_SAM_00,
584 [LOWPAN_IPHC_DAM_01] = LOWPAN_IPHC_SAM_01,
585 [LOWPAN_IPHC_DAM_10] = LOWPAN_IPHC_SAM_10,
586 [LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
587 };
588
lowpan_compress_addr_64(u8 ** hc_ptr,const struct in6_addr * ipaddr,const unsigned char * lladdr,bool sam)589 static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct in6_addr *ipaddr,
590 const unsigned char *lladdr, bool sam)
591 {
592 u8 dam = LOWPAN_IPHC_DAM_00;
593
594 if (is_addr_mac_addr_based(ipaddr, lladdr)) {
595 dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
596 pr_debug("address compression 0 bits\n");
597 } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
598 /* compress IID to 16 bits xxxx::XXXX */
599 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
600 dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
601 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
602 *hc_ptr - 2, 2);
603 } else {
604 /* do not compress IID => xxxx::IID */
605 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
606 dam = LOWPAN_IPHC_DAM_01; /* 64-bits */
607 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
608 *hc_ptr - 8, 8);
609 }
610
611 if (sam)
612 return lowpan_iphc_dam_to_sam_value[dam];
613 else
614 return dam;
615 }
616
617 /* lowpan_iphc_get_tc - get the ECN + DCSP fields in hc format */
lowpan_iphc_get_tc(const struct ipv6hdr * hdr)618 static inline u8 lowpan_iphc_get_tc(const struct ipv6hdr *hdr)
619 {
620 u8 dscp, ecn;
621
622 /* hdr->priority contains the higher bits of dscp, lower are part of
623 * flow_lbl[0]. Note ECN, DCSP is swapped in ipv6 hdr.
624 */
625 dscp = (hdr->priority << 2) | ((hdr->flow_lbl[0] & 0xc0) >> 6);
626 /* ECN is at the two lower bits from first nibble of flow_lbl[0] */
627 ecn = (hdr->flow_lbl[0] & 0x30);
628 /* for pretty debug output, also shift ecn to get the ecn value */
629 pr_debug("ecn 0x%02x dscp 0x%02x\n", ecn >> 4, dscp);
630 /* ECN is at 0x30 now, shift it to have ECN + DCSP */
631 return (ecn << 2) | dscp;
632 }
633
634 /* lowpan_iphc_is_flow_lbl_zero - check if flow label is zero */
lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr * hdr)635 static inline bool lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr *hdr)
636 {
637 return ((!(hdr->flow_lbl[0] & 0x0f)) &&
638 !hdr->flow_lbl[1] && !hdr->flow_lbl[2]);
639 }
640
641 /* lowpan_iphc_tf_compress - compress the traffic class which is set by
642 * ipv6hdr. Return the corresponding format identifier which is used.
643 */
lowpan_iphc_tf_compress(u8 ** hc_ptr,const struct ipv6hdr * hdr)644 static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
645 {
646 /* get ecn dscp data in a byteformat as: ECN(hi) + DSCP(lo) */
647 u8 tc = lowpan_iphc_get_tc(hdr), tf[4], val;
648
649 /* printout the traffic class in hc format */
650 pr_debug("tc 0x%02x\n", tc);
651
652 if (lowpan_iphc_is_flow_lbl_zero(hdr)) {
653 if (!tc) {
654 /* 11: Traffic Class and Flow Label are elided. */
655 val = LOWPAN_IPHC_TF_11;
656 } else {
657 /* 10: ECN + DSCP (1 byte), Flow Label is elided.
658 *
659 * 0 1 2 3 4 5 6 7
660 * +-+-+-+-+-+-+-+-+
661 * |ECN| DSCP |
662 * +-+-+-+-+-+-+-+-+
663 */
664 lowpan_push_hc_data(hc_ptr, &tc, sizeof(tc));
665 val = LOWPAN_IPHC_TF_10;
666 }
667 } else {
668 /* check if dscp is zero, it's after the first two bit */
669 if (!(tc & 0x3f)) {
670 /* 01: ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
671 *
672 * 1 2
673 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
674 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
675 * |ECN|rsv| Flow Label |
676 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
677 */
678 memcpy(&tf[0], &hdr->flow_lbl[0], 3);
679 /* zero the highest 4-bits, contains DCSP + ECN */
680 tf[0] &= ~0xf0;
681 /* set ECN */
682 tf[0] |= (tc & 0xc0);
683
684 lowpan_push_hc_data(hc_ptr, tf, 3);
685 val = LOWPAN_IPHC_TF_01;
686 } else {
687 /* 00: ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
688 *
689 * 1 2 3
690 * 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
691 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
692 * |ECN| DSCP | rsv | Flow Label |
693 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
694 */
695 memcpy(&tf[0], &tc, sizeof(tc));
696 /* highest nibble of flow_lbl[0] is part of DSCP + ECN
697 * which will be the 4-bit pad and will be filled with
698 * zeros afterwards.
699 */
700 memcpy(&tf[1], &hdr->flow_lbl[0], 3);
701 /* zero the 4-bit pad, which is reserved */
702 tf[1] &= ~0xf0;
703
704 lowpan_push_hc_data(hc_ptr, tf, 4);
705 val = LOWPAN_IPHC_TF_00;
706 }
707 }
708
709 return val;
710 }
711
lowpan_iphc_mcast_addr_compress(u8 ** hc_ptr,const struct in6_addr * ipaddr)712 static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
713 const struct in6_addr *ipaddr)
714 {
715 u8 val;
716
717 if (lowpan_is_mcast_addr_compressable8(ipaddr)) {
718 pr_debug("compressed to 1 octet\n");
719 /* use last byte */
720 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[15], 1);
721 val = LOWPAN_IPHC_DAM_11;
722 } else if (lowpan_is_mcast_addr_compressable32(ipaddr)) {
723 pr_debug("compressed to 4 octets\n");
724 /* second byte + the last three */
725 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
726 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[13], 3);
727 val = LOWPAN_IPHC_DAM_10;
728 } else if (lowpan_is_mcast_addr_compressable48(ipaddr)) {
729 pr_debug("compressed to 6 octets\n");
730 /* second byte + the last five */
731 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
732 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[11], 5);
733 val = LOWPAN_IPHC_DAM_01;
734 } else {
735 pr_debug("using full address\n");
736 lowpan_push_hc_data(hc_ptr, ipaddr->s6_addr, 16);
737 val = LOWPAN_IPHC_DAM_00;
738 }
739
740 return val;
741 }
742
lowpan_header_compress(struct sk_buff * skb,const struct net_device * dev,const void * daddr,const void * saddr)743 int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
744 const void *daddr, const void *saddr)
745 {
746 u8 iphc0, iphc1, *hc_ptr;
747 struct ipv6hdr *hdr;
748 u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
749 int ret, addr_type;
750
751 if (skb->protocol != htons(ETH_P_IPV6))
752 return -EINVAL;
753
754 hdr = ipv6_hdr(skb);
755 hc_ptr = head + 2;
756
757 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
758 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
759 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
760 hdr->hop_limit, &hdr->daddr);
761
762 raw_dump_table(__func__, "raw skb network header dump",
763 skb_network_header(skb), sizeof(struct ipv6hdr));
764
765 /* As we copy some bit-length fields, in the IPHC encoding bytes,
766 * we sometimes use |=
767 * If the field is 0, and the current bit value in memory is 1,
768 * this does not work. We therefore reset the IPHC encoding here
769 */
770 iphc0 = LOWPAN_DISPATCH_IPHC;
771 iphc1 = 0;
772
773 /* TODO: context lookup */
774
775 raw_dump_inline(__func__, "saddr", saddr, EUI64_ADDR_LEN);
776 raw_dump_inline(__func__, "daddr", daddr, EUI64_ADDR_LEN);
777
778 raw_dump_table(__func__, "sending raw skb network uncompressed packet",
779 skb->data, skb->len);
780
781 /* Traffic Class, Flow Label compression */
782 iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
783
784 /* NOTE: payload length is always compressed */
785
786 /* Check if we provide the nhc format for nexthdr and compression
787 * functionality. If not nexthdr is handled inline and not compressed.
788 */
789 ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr);
790 if (ret == -ENOENT)
791 lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
792 sizeof(hdr->nexthdr));
793 else
794 iphc0 |= LOWPAN_IPHC_NH;
795
796 /* Hop limit
797 * if 1: compress, encoding is 01
798 * if 64: compress, encoding is 10
799 * if 255: compress, encoding is 11
800 * else do not compress
801 */
802 switch (hdr->hop_limit) {
803 case 1:
804 iphc0 |= LOWPAN_IPHC_HLIM_01;
805 break;
806 case 64:
807 iphc0 |= LOWPAN_IPHC_HLIM_10;
808 break;
809 case 255:
810 iphc0 |= LOWPAN_IPHC_HLIM_11;
811 break;
812 default:
813 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
814 sizeof(hdr->hop_limit));
815 }
816
817 addr_type = ipv6_addr_type(&hdr->saddr);
818 /* source address compression */
819 if (addr_type == IPV6_ADDR_ANY) {
820 pr_debug("source address is unspecified, setting SAC\n");
821 iphc1 |= LOWPAN_IPHC_SAC;
822 } else {
823 if (addr_type & IPV6_ADDR_LINKLOCAL) {
824 iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->saddr,
825 saddr, true);
826 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
827 &hdr->saddr, iphc1);
828 } else {
829 pr_debug("send the full source address\n");
830 lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16);
831 }
832 }
833
834 addr_type = ipv6_addr_type(&hdr->daddr);
835 /* destination address compression */
836 if (addr_type & IPV6_ADDR_MULTICAST) {
837 pr_debug("destination address is multicast: ");
838 iphc1 |= LOWPAN_IPHC_M;
839 iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr, &hdr->daddr);
840 } else {
841 if (addr_type & IPV6_ADDR_LINKLOCAL) {
842 /* TODO: context lookup */
843 iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->daddr,
844 daddr, false);
845 pr_debug("dest address unicast link-local %pI6c "
846 "iphc1 0x%02x\n", &hdr->daddr, iphc1);
847 } else {
848 pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
849 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
850 }
851 }
852
853 /* next header compression */
854 if (iphc0 & LOWPAN_IPHC_NH) {
855 ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
856 if (ret < 0)
857 return ret;
858 }
859
860 head[0] = iphc0;
861 head[1] = iphc1;
862
863 skb_pull(skb, sizeof(struct ipv6hdr));
864 skb_reset_transport_header(skb);
865 memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
866 skb_reset_network_header(skb);
867
868 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
869
870 raw_dump_table(__func__, "raw skb data dump compressed",
871 skb->data, skb->len);
872 return 0;
873 }
874 EXPORT_SYMBOL_GPL(lowpan_header_compress);
875