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-rw-r--r--net/6lowpan/iphc.c789
1 files changed, 789 insertions, 0 deletions
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
new file mode 100644
index 000000000000..142eef55c9e2
--- /dev/null
+++ b/net/6lowpan/iphc.c
@@ -0,0 +1,789 @@
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 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21 */
22
23/* Jon's code is based on 6lowpan implementation for Contiki which is:
24 * Copyright (c) 2008, Swedish Institute of Computer Science.
25 * All rights reserved.
26 *
27 * Redistribution and use in source and binary forms, with or without
28 * modification, are permitted provided that the following conditions
29 * are met:
30 * 1. Redistributions of source code must retain the above copyright
31 * notice, this list of conditions and the following disclaimer.
32 * 2. Redistributions in binary form must reproduce the above copyright
33 * notice, this list of conditions and the following disclaimer in the
34 * documentation and/or other materials provided with the distribution.
35 * 3. Neither the name of the Institute nor the names of its contributors
36 * may be used to endorse or promote products derived from this software
37 * without specific prior written permission.
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
40 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
42 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
43 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
44 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
45 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
47 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
48 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
49 * SUCH DAMAGE.
50 */
51
52#include <linux/bitops.h>
53#include <linux/if_arp.h>
54#include <linux/module.h>
55#include <linux/netdevice.h>
56#include <net/6lowpan.h>
57#include <net/ipv6.h>
58#include <net/af_ieee802154.h>
59
60/* Uncompress address function for source and
61 * destination address(non-multicast).
62 *
63 * address_mode is sam value or dam value.
64 */
65static int uncompress_addr(struct sk_buff *skb,
66 struct in6_addr *ipaddr, const u8 address_mode,
67 const u8 *lladdr, const u8 addr_type,
68 const u8 addr_len)
69{
70 bool fail;
71
72 switch (address_mode) {
73 case LOWPAN_IPHC_ADDR_00:
74 /* for global link addresses */
75 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
76 break;
77 case LOWPAN_IPHC_ADDR_01:
78 /* fe:80::XXXX:XXXX:XXXX:XXXX */
79 ipaddr->s6_addr[0] = 0xFE;
80 ipaddr->s6_addr[1] = 0x80;
81 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
82 break;
83 case LOWPAN_IPHC_ADDR_02:
84 /* fe:80::ff:fe00:XXXX */
85 ipaddr->s6_addr[0] = 0xFE;
86 ipaddr->s6_addr[1] = 0x80;
87 ipaddr->s6_addr[11] = 0xFF;
88 ipaddr->s6_addr[12] = 0xFE;
89 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
90 break;
91 case LOWPAN_IPHC_ADDR_03:
92 fail = false;
93 switch (addr_type) {
94 case IEEE802154_ADDR_LONG:
95 /* fe:80::XXXX:XXXX:XXXX:XXXX
96 * \_________________/
97 * hwaddr
98 */
99 ipaddr->s6_addr[0] = 0xFE;
100 ipaddr->s6_addr[1] = 0x80;
101 memcpy(&ipaddr->s6_addr[8], lladdr, addr_len);
102 /* second bit-flip (Universe/Local)
103 * is done according RFC2464
104 */
105 ipaddr->s6_addr[8] ^= 0x02;
106 break;
107 case IEEE802154_ADDR_SHORT:
108 /* fe:80::ff:fe00:XXXX
109 * \__/
110 * short_addr
111 *
112 * Universe/Local bit is zero.
113 */
114 ipaddr->s6_addr[0] = 0xFE;
115 ipaddr->s6_addr[1] = 0x80;
116 ipaddr->s6_addr[11] = 0xFF;
117 ipaddr->s6_addr[12] = 0xFE;
118 ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr));
119 break;
120 default:
121 pr_debug("Invalid addr_type set\n");
122 return -EINVAL;
123 }
124 break;
125 default:
126 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
127 return -EINVAL;
128 }
129
130 if (fail) {
131 pr_debug("Failed to fetch skb data\n");
132 return -EIO;
133 }
134
135 raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
136 ipaddr->s6_addr, 16);
137
138 return 0;
139}
140
141/* Uncompress address function for source context
142 * based address(non-multicast).
143 */
144static int uncompress_context_based_src_addr(struct sk_buff *skb,
145 struct in6_addr *ipaddr,
146 const u8 sam)
147{
148 switch (sam) {
149 case LOWPAN_IPHC_ADDR_00:
150 /* unspec address ::
151 * Do nothing, address is already ::
152 */
153 break;
154 case LOWPAN_IPHC_ADDR_01:
155 /* TODO */
156 case LOWPAN_IPHC_ADDR_02:
157 /* TODO */
158 case LOWPAN_IPHC_ADDR_03:
159 /* TODO */
160 netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
161 return -EINVAL;
162 default:
163 pr_debug("Invalid sam value: 0x%x\n", sam);
164 return -EINVAL;
165 }
166
167 raw_dump_inline(NULL,
168 "Reconstructed context based ipv6 src addr is",
169 ipaddr->s6_addr, 16);
170
171 return 0;
172}
173
174static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
175 struct net_device *dev, skb_delivery_cb deliver_skb)
176{
177 struct sk_buff *new;
178 int stat;
179
180 new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
181 GFP_ATOMIC);
182 kfree_skb(skb);
183
184 if (!new)
185 return -ENOMEM;
186
187 skb_push(new, sizeof(struct ipv6hdr));
188 skb_reset_network_header(new);
189 skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
190
191 new->protocol = htons(ETH_P_IPV6);
192 new->pkt_type = PACKET_HOST;
193 new->dev = dev;
194
195 raw_dump_table(__func__, "raw skb data dump before receiving",
196 new->data, new->len);
197
198 stat = deliver_skb(new, dev);
199
200 kfree_skb(new);
201
202 return stat;
203}
204
205/* Uncompress function for multicast destination address,
206 * when M bit is set.
207 */
208static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
209 struct in6_addr *ipaddr,
210 const u8 dam)
211{
212 bool fail;
213
214 switch (dam) {
215 case LOWPAN_IPHC_DAM_00:
216 /* 00: 128 bits. The full address
217 * is carried in-line.
218 */
219 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
220 break;
221 case LOWPAN_IPHC_DAM_01:
222 /* 01: 48 bits. The address takes
223 * the form ffXX::00XX:XXXX:XXXX.
224 */
225 ipaddr->s6_addr[0] = 0xFF;
226 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
227 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
228 break;
229 case LOWPAN_IPHC_DAM_10:
230 /* 10: 32 bits. The address takes
231 * the form ffXX::00XX:XXXX.
232 */
233 ipaddr->s6_addr[0] = 0xFF;
234 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
235 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
236 break;
237 case LOWPAN_IPHC_DAM_11:
238 /* 11: 8 bits. The address takes
239 * the form ff02::00XX.
240 */
241 ipaddr->s6_addr[0] = 0xFF;
242 ipaddr->s6_addr[1] = 0x02;
243 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
244 break;
245 default:
246 pr_debug("DAM value has a wrong value: 0x%x\n", dam);
247 return -EINVAL;
248 }
249
250 if (fail) {
251 pr_debug("Failed to fetch skb data\n");
252 return -EIO;
253 }
254
255 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
256 ipaddr->s6_addr, 16);
257
258 return 0;
259}
260
261static int uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
262{
263 bool fail;
264 u8 tmp = 0, val = 0;
265
266 fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp));
267
268 if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
269 pr_debug("UDP header uncompression\n");
270 switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
271 case LOWPAN_NHC_UDP_CS_P_00:
272 fail |= lowpan_fetch_skb(skb, &uh->source,
273 sizeof(uh->source));
274 fail |= lowpan_fetch_skb(skb, &uh->dest,
275 sizeof(uh->dest));
276 break;
277 case LOWPAN_NHC_UDP_CS_P_01:
278 fail |= lowpan_fetch_skb(skb, &uh->source,
279 sizeof(uh->source));
280 fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
281 uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
282 break;
283 case LOWPAN_NHC_UDP_CS_P_10:
284 fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
285 uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
286 fail |= lowpan_fetch_skb(skb, &uh->dest,
287 sizeof(uh->dest));
288 break;
289 case LOWPAN_NHC_UDP_CS_P_11:
290 fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
291 uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT +
292 (val >> 4));
293 uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT +
294 (val & 0x0f));
295 break;
296 default:
297 pr_debug("ERROR: unknown UDP format\n");
298 goto err;
299 }
300
301 pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
302 ntohs(uh->source), ntohs(uh->dest));
303
304 /* checksum */
305 if (tmp & LOWPAN_NHC_UDP_CS_C) {
306 pr_debug_ratelimited("checksum elided currently not supported\n");
307 goto err;
308 } else {
309 fail |= lowpan_fetch_skb(skb, &uh->check,
310 sizeof(uh->check));
311 }
312
313 /* UDP length needs to be infered from the lower layers
314 * here, we obtain the hint from the remaining size of the
315 * frame
316 */
317 uh->len = htons(skb->len + sizeof(struct udphdr));
318 pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len));
319 } else {
320 pr_debug("ERROR: unsupported NH format\n");
321 goto err;
322 }
323
324 if (fail)
325 goto err;
326
327 return 0;
328err:
329 return -EINVAL;
330}
331
332/* TTL uncompression values */
333static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
334
335int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
336 const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
337 const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
338 u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
339{
340 struct ipv6hdr hdr = {};
341 u8 tmp, num_context = 0;
342 int err;
343
344 raw_dump_table(__func__, "raw skb data dump uncompressed",
345 skb->data, skb->len);
346
347 /* another if the CID flag is set */
348 if (iphc1 & LOWPAN_IPHC_CID) {
349 pr_debug("CID flag is set, increase header with one\n");
350 if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context)))
351 goto drop;
352 }
353
354 hdr.version = 6;
355
356 /* Traffic Class and Flow Label */
357 switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
358 /* Traffic Class and FLow Label carried in-line
359 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
360 */
361 case 0: /* 00b */
362 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
363 goto drop;
364
365 memcpy(&hdr.flow_lbl, &skb->data[0], 3);
366 skb_pull(skb, 3);
367 hdr.priority = ((tmp >> 2) & 0x0f);
368 hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
369 (hdr.flow_lbl[0] & 0x0f);
370 break;
371 /* Traffic class carried in-line
372 * ECN + DSCP (1 byte), Flow Label is elided
373 */
374 case 2: /* 10b */
375 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
376 goto drop;
377
378 hdr.priority = ((tmp >> 2) & 0x0f);
379 hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
380 break;
381 /* Flow Label carried in-line
382 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
383 */
384 case 1: /* 01b */
385 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
386 goto drop;
387
388 hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
389 memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
390 skb_pull(skb, 2);
391 break;
392 /* Traffic Class and Flow Label are elided */
393 case 3: /* 11b */
394 break;
395 default:
396 break;
397 }
398
399 /* Next Header */
400 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
401 /* Next header is carried inline */
402 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
403 goto drop;
404
405 pr_debug("NH flag is set, next header carried inline: %02x\n",
406 hdr.nexthdr);
407 }
408
409 /* Hop Limit */
410 if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) {
411 hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
412 } else {
413 if (lowpan_fetch_skb(skb, &hdr.hop_limit,
414 sizeof(hdr.hop_limit)))
415 goto drop;
416 }
417
418 /* Extract SAM to the tmp variable */
419 tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
420
421 if (iphc1 & LOWPAN_IPHC_SAC) {
422 /* Source address context based uncompression */
423 pr_debug("SAC bit is set. Handle context based source address.\n");
424 err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp);
425 } else {
426 /* Source address uncompression */
427 pr_debug("source address stateless compression\n");
428 err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
429 saddr_type, saddr_len);
430 }
431
432 /* Check on error of previous branch */
433 if (err)
434 goto drop;
435
436 /* Extract DAM to the tmp variable */
437 tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
438
439 /* check for Multicast Compression */
440 if (iphc1 & LOWPAN_IPHC_M) {
441 if (iphc1 & LOWPAN_IPHC_DAC) {
442 pr_debug("dest: context-based mcast compression\n");
443 /* TODO: implement this */
444 } else {
445 err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
446 tmp);
447
448 if (err)
449 goto drop;
450 }
451 } else {
452 err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
453 daddr_type, daddr_len);
454 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
455 tmp, &hdr.daddr);
456 if (err)
457 goto drop;
458 }
459
460 /* UDP data uncompression */
461 if (iphc0 & LOWPAN_IPHC_NH_C) {
462 struct udphdr uh;
463 struct sk_buff *new;
464
465 if (uncompress_udp_header(skb, &uh))
466 goto drop;
467
468 /* replace the compressed UDP head by the uncompressed UDP
469 * header
470 */
471 new = skb_copy_expand(skb, sizeof(struct udphdr),
472 skb_tailroom(skb), GFP_ATOMIC);
473 kfree_skb(skb);
474
475 if (!new)
476 return -ENOMEM;
477
478 skb = new;
479
480 skb_push(skb, sizeof(struct udphdr));
481 skb_reset_transport_header(skb);
482 skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
483
484 raw_dump_table(__func__, "raw UDP header dump",
485 (u8 *)&uh, sizeof(uh));
486
487 hdr.nexthdr = UIP_PROTO_UDP;
488 }
489
490 hdr.payload_len = htons(skb->len);
491
492 pr_debug("skb headroom size = %d, data length = %d\n",
493 skb_headroom(skb), skb->len);
494
495 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
496 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
497 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
498 hdr.hop_limit, &hdr.daddr);
499
500 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
501
502 return skb_deliver(skb, &hdr, dev, deliver_skb);
503
504drop:
505 kfree_skb(skb);
506 return -EINVAL;
507}
508EXPORT_SYMBOL_GPL(lowpan_process_data);
509
510static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift,
511 const struct in6_addr *ipaddr,
512 const unsigned char *lladdr)
513{
514 u8 val = 0;
515
516 if (is_addr_mac_addr_based(ipaddr, lladdr)) {
517 val = 3; /* 0-bits */
518 pr_debug("address compression 0 bits\n");
519 } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
520 /* compress IID to 16 bits xxxx::XXXX */
521 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
522 val = 2; /* 16-bits */
523 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
524 *hc_ptr - 2, 2);
525 } else {
526 /* do not compress IID => xxxx::IID */
527 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
528 val = 1; /* 64-bits */
529 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
530 *hc_ptr - 8, 8);
531 }
532
533 return rol8(val, shift);
534}
535
536static void compress_udp_header(u8 **hc_ptr, struct sk_buff *skb)
537{
538 struct udphdr *uh = udp_hdr(skb);
539 u8 tmp;
540
541 if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) ==
542 LOWPAN_NHC_UDP_4BIT_PORT) &&
543 ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) ==
544 LOWPAN_NHC_UDP_4BIT_PORT)) {
545 pr_debug("UDP header: both ports compression to 4 bits\n");
546 /* compression value */
547 tmp = LOWPAN_NHC_UDP_CS_P_11;
548 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
549 /* source and destination port */
550 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT +
551 ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4);
552 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
553 } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) ==
554 LOWPAN_NHC_UDP_8BIT_PORT) {
555 pr_debug("UDP header: remove 8 bits of dest\n");
556 /* compression value */
557 tmp = LOWPAN_NHC_UDP_CS_P_01;
558 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
559 /* source port */
560 lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
561 /* destination port */
562 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT;
563 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
564 } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) ==
565 LOWPAN_NHC_UDP_8BIT_PORT) {
566 pr_debug("UDP header: remove 8 bits of source\n");
567 /* compression value */
568 tmp = LOWPAN_NHC_UDP_CS_P_10;
569 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
570 /* source port */
571 tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT;
572 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
573 /* destination port */
574 lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
575 } else {
576 pr_debug("UDP header: can't compress\n");
577 /* compression value */
578 tmp = LOWPAN_NHC_UDP_CS_P_00;
579 lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
580 /* source port */
581 lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
582 /* destination port */
583 lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
584 }
585
586 /* checksum is always inline */
587 lowpan_push_hc_data(hc_ptr, &uh->check, sizeof(uh->check));
588
589 /* skip the UDP header */
590 skb_pull(skb, sizeof(struct udphdr));
591}
592
593int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
594 unsigned short type, const void *_daddr,
595 const void *_saddr, unsigned int len)
596{
597 u8 tmp, iphc0, iphc1, *hc_ptr;
598 struct ipv6hdr *hdr;
599 u8 head[100] = {};
600 int addr_type;
601
602 if (type != ETH_P_IPV6)
603 return -EINVAL;
604
605 hdr = ipv6_hdr(skb);
606 hc_ptr = head + 2;
607
608 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
609 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
610 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
611 hdr->hop_limit, &hdr->daddr);
612
613 raw_dump_table(__func__, "raw skb network header dump",
614 skb_network_header(skb), sizeof(struct ipv6hdr));
615
616 /* As we copy some bit-length fields, in the IPHC encoding bytes,
617 * we sometimes use |=
618 * If the field is 0, and the current bit value in memory is 1,
619 * this does not work. We therefore reset the IPHC encoding here
620 */
621 iphc0 = LOWPAN_DISPATCH_IPHC;
622 iphc1 = 0;
623
624 /* TODO: context lookup */
625
626 raw_dump_inline(__func__, "saddr",
627 (unsigned char *)_saddr, IEEE802154_ADDR_LEN);
628 raw_dump_inline(__func__, "daddr",
629 (unsigned char *)_daddr, IEEE802154_ADDR_LEN);
630
631 raw_dump_table(__func__, "sending raw skb network uncompressed packet",
632 skb->data, skb->len);
633
634 /* Traffic class, flow label
635 * If flow label is 0, compress it. If traffic class is 0, compress it
636 * We have to process both in the same time as the offset of traffic
637 * class depends on the presence of version and flow label
638 */
639
640 /* hc format of TC is ECN | DSCP , original one is DSCP | ECN */
641 tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
642 tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
643
644 if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
645 (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
646 /* flow label can be compressed */
647 iphc0 |= LOWPAN_IPHC_FL_C;
648 if ((hdr->priority == 0) &&
649 ((hdr->flow_lbl[0] & 0xF0) == 0)) {
650 /* compress (elide) all */
651 iphc0 |= LOWPAN_IPHC_TC_C;
652 } else {
653 /* compress only the flow label */
654 *hc_ptr = tmp;
655 hc_ptr += 1;
656 }
657 } else {
658 /* Flow label cannot be compressed */
659 if ((hdr->priority == 0) &&
660 ((hdr->flow_lbl[0] & 0xF0) == 0)) {
661 /* compress only traffic class */
662 iphc0 |= LOWPAN_IPHC_TC_C;
663 *hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
664 memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2);
665 hc_ptr += 3;
666 } else {
667 /* compress nothing */
668 memcpy(hc_ptr, hdr, 4);
669 /* replace the top byte with new ECN | DSCP format */
670 *hc_ptr = tmp;
671 hc_ptr += 4;
672 }
673 }
674
675 /* NOTE: payload length is always compressed */
676
677 /* Next Header is compress if UDP */
678 if (hdr->nexthdr == UIP_PROTO_UDP)
679 iphc0 |= LOWPAN_IPHC_NH_C;
680
681 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0)
682 lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
683 sizeof(hdr->nexthdr));
684
685 /* Hop limit
686 * if 1: compress, encoding is 01
687 * if 64: compress, encoding is 10
688 * if 255: compress, encoding is 11
689 * else do not compress
690 */
691 switch (hdr->hop_limit) {
692 case 1:
693 iphc0 |= LOWPAN_IPHC_TTL_1;
694 break;
695 case 64:
696 iphc0 |= LOWPAN_IPHC_TTL_64;
697 break;
698 case 255:
699 iphc0 |= LOWPAN_IPHC_TTL_255;
700 break;
701 default:
702 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
703 sizeof(hdr->hop_limit));
704 }
705
706 addr_type = ipv6_addr_type(&hdr->saddr);
707 /* source address compression */
708 if (addr_type == IPV6_ADDR_ANY) {
709 pr_debug("source address is unspecified, setting SAC\n");
710 iphc1 |= LOWPAN_IPHC_SAC;
711 } else {
712 if (addr_type & IPV6_ADDR_LINKLOCAL) {
713 iphc1 |= lowpan_compress_addr_64(&hc_ptr,
714 LOWPAN_IPHC_SAM_BIT,
715 &hdr->saddr, _saddr);
716 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
717 &hdr->saddr, iphc1);
718 } else {
719 pr_debug("send the full source address\n");
720 lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16);
721 }
722 }
723
724 addr_type = ipv6_addr_type(&hdr->daddr);
725 /* destination address compression */
726 if (addr_type & IPV6_ADDR_MULTICAST) {
727 pr_debug("destination address is multicast: ");
728 iphc1 |= LOWPAN_IPHC_M;
729 if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
730 pr_debug("compressed to 1 octet\n");
731 iphc1 |= LOWPAN_IPHC_DAM_11;
732 /* use last byte */
733 lowpan_push_hc_data(&hc_ptr,
734 &hdr->daddr.s6_addr[15], 1);
735 } else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
736 pr_debug("compressed to 4 octets\n");
737 iphc1 |= LOWPAN_IPHC_DAM_10;
738 /* second byte + the last three */
739 lowpan_push_hc_data(&hc_ptr,
740 &hdr->daddr.s6_addr[1], 1);
741 lowpan_push_hc_data(&hc_ptr,
742 &hdr->daddr.s6_addr[13], 3);
743 } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
744 pr_debug("compressed to 6 octets\n");
745 iphc1 |= LOWPAN_IPHC_DAM_01;
746 /* second byte + the last five */
747 lowpan_push_hc_data(&hc_ptr,
748 &hdr->daddr.s6_addr[1], 1);
749 lowpan_push_hc_data(&hc_ptr,
750 &hdr->daddr.s6_addr[11], 5);
751 } else {
752 pr_debug("using full address\n");
753 iphc1 |= LOWPAN_IPHC_DAM_00;
754 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
755 }
756 } else {
757 if (addr_type & IPV6_ADDR_LINKLOCAL) {
758 /* TODO: context lookup */
759 iphc1 |= lowpan_compress_addr_64(&hc_ptr,
760 LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr);
761 pr_debug("dest address unicast link-local %pI6c "
762 "iphc1 0x%02x\n", &hdr->daddr, iphc1);
763 } else {
764 pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
765 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
766 }
767 }
768
769 /* UDP header compression */
770 if (hdr->nexthdr == UIP_PROTO_UDP)
771 compress_udp_header(&hc_ptr, skb);
772
773 head[0] = iphc0;
774 head[1] = iphc1;
775
776 skb_pull(skb, sizeof(struct ipv6hdr));
777 skb_reset_transport_header(skb);
778 memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
779 skb_reset_network_header(skb);
780
781 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
782
783 raw_dump_table(__func__, "raw skb data dump compressed",
784 skb->data, skb->len);
785 return 0;
786}
787EXPORT_SYMBOL_GPL(lowpan_header_compress);
788
789MODULE_LICENSE("GPL");
generated by cgit v1.2.2 (git 2.25.0) at 2025-05-23 18:24:27 -0400