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-rw-r--r--net/6lowpan/iphc.c801
1 files changed, 801 insertions, 0 deletions
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
new file mode 100644
index 000000000000..211b5686d719
--- /dev/null
+++ b/net/6lowpan/iphc.c
@@ -0,0 +1,801 @@
1/*
2 * Copyright 2011, Siemens AG
3 * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
4 */
5
6/*
7 * Based on patches from Jon Smirl <jonsmirl@gmail.com>
8 * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22 */
23
24/* Jon's code is based on 6lowpan implementation for Contiki which is:
25 * Copyright (c) 2008, Swedish Institute of Computer Science.
26 * All rights reserved.
27 *
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
30 * are met:
31 * 1. Redistributions of source code must retain the above copyright
32 * notice, this list of conditions and the following disclaimer.
33 * 2. Redistributions in binary form must reproduce the above copyright
34 * notice, this list of conditions and the following disclaimer in the
35 * documentation and/or other materials provided with the distribution.
36 * 3. Neither the name of the Institute nor the names of its contributors
37 * may be used to endorse or promote products derived from this software
38 * without specific prior written permission.
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 */
52
53#include <linux/bitops.h>
54#include <linux/if_arp.h>
55#include <linux/module.h>
56#include <linux/netdevice.h>
57#include <net/6lowpan.h>
58#include <net/ipv6.h>
59#include <net/af_ieee802154.h>
60
61/*
62 * Uncompress address function for source and
63 * destination address(non-multicast).
64 *
65 * address_mode is sam value or dam value.
66 */
67static int uncompress_addr(struct sk_buff *skb,
68 struct in6_addr *ipaddr, const u8 address_mode,
69 const u8 *lladdr, const u8 addr_type,
70 const u8 addr_len)
71{
72 bool fail;
73
74 switch (address_mode) {
75 case LOWPAN_IPHC_ADDR_00:
76 /* for global link addresses */
77 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
78 break;
79 case LOWPAN_IPHC_ADDR_01:
80 /* fe:80::XXXX:XXXX:XXXX:XXXX */
81 ipaddr->s6_addr[0] = 0xFE;
82 ipaddr->s6_addr[1] = 0x80;
83 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
84 break;
85 case LOWPAN_IPHC_ADDR_02:
86 /* fe:80::ff:fe00:XXXX */
87 ipaddr->s6_addr[0] = 0xFE;
88 ipaddr->s6_addr[1] = 0x80;
89 ipaddr->s6_addr[11] = 0xFF;
90 ipaddr->s6_addr[12] = 0xFE;
91 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
92 break;
93 case LOWPAN_IPHC_ADDR_03:
94 fail = false;
95 switch (addr_type) {
96 case IEEE802154_ADDR_LONG:
97 /* fe:80::XXXX:XXXX:XXXX:XXXX
98 * \_________________/
99 * hwaddr
100 */
101 ipaddr->s6_addr[0] = 0xFE;
102 ipaddr->s6_addr[1] = 0x80;
103 memcpy(&ipaddr->s6_addr[8], lladdr, addr_len);
104 /* second bit-flip (Universe/Local)
105 * is done according RFC2464
106 */
107 ipaddr->s6_addr[8] ^= 0x02;
108 break;
109 case IEEE802154_ADDR_SHORT:
110 /* fe:80::ff:fe00:XXXX
111 * \__/
112 * short_addr
113 *
114 * Universe/Local bit is zero.
115 */
116 ipaddr->s6_addr[0] = 0xFE;
117 ipaddr->s6_addr[1] = 0x80;
118 ipaddr->s6_addr[11] = 0xFF;
119 ipaddr->s6_addr[12] = 0xFE;
120 ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr));
121 break;
122 default:
123 pr_debug("Invalid addr_type set\n");
124 return -EINVAL;
125 }
126 break;
127 default:
128 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
129 return -EINVAL;
130 }
131
132 if (fail) {
133 pr_debug("Failed to fetch skb data\n");
134 return -EIO;
135 }
136
137 raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
138 ipaddr->s6_addr, 16);
139
140 return 0;
141}
142
143/*
144 * Uncompress address function for source context
145 * based address(non-multicast).
146 */
147static int uncompress_context_based_src_addr(struct sk_buff *skb,
148 struct in6_addr *ipaddr,
149 const u8 sam)
150{
151 switch (sam) {
152 case LOWPAN_IPHC_ADDR_00:
153 /* unspec address ::
154 * Do nothing, address is already ::
155 */
156 break;
157 case LOWPAN_IPHC_ADDR_01:
158 /* TODO */
159 case LOWPAN_IPHC_ADDR_02:
160 /* TODO */
161 case LOWPAN_IPHC_ADDR_03:
162 /* TODO */
163 netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
164 return -EINVAL;
165 default:
166 pr_debug("Invalid sam value: 0x%x\n", sam);
167 return -EINVAL;
168 }
169
170 raw_dump_inline(NULL,
171 "Reconstructed context based ipv6 src addr is",
172 ipaddr->s6_addr, 16);
173
174 return 0;
175}
176
177static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
178 struct net_device *dev, skb_delivery_cb deliver_skb)
179{
180 struct sk_buff *new;
181 int stat;
182
183 new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
184 GFP_ATOMIC);
185 kfree_skb(skb);
186
187 if (!new)
188 return -ENOMEM;
189
190 skb_push(new, sizeof(struct ipv6hdr));
191 skb_reset_network_header(new);
192 skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
193
194 new->protocol = htons(ETH_P_IPV6);
195 new->pkt_type = PACKET_HOST;
196 new->dev = dev;
197
198 raw_dump_table(__func__, "raw skb data dump before receiving",
199 new->data, new->len);
200
201 stat = deliver_skb(new, dev);
202
203 kfree_skb(new);
204
205 return stat;
206}
207
208/* Uncompress function for multicast destination address,
209 * when M bit is set.
210 */
211static int
212lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
213 struct in6_addr *ipaddr,
214 const u8 dam)
215{
216 bool fail;
217
218 switch (dam) {
219 case LOWPAN_IPHC_DAM_00:
220 /* 00: 128 bits. The full address
221 * is carried in-line.
222 */
223 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
224 break;
225 case LOWPAN_IPHC_DAM_01:
226 /* 01: 48 bits. The address takes
227 * the form ffXX::00XX:XXXX:XXXX.
228 */
229 ipaddr->s6_addr[0] = 0xFF;
230 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
231 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
232 break;
233 case LOWPAN_IPHC_DAM_10:
234 /* 10: 32 bits. The address takes
235 * the form ffXX::00XX:XXXX.
236 */
237 ipaddr->s6_addr[0] = 0xFF;
238 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
239 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
240 break;
241 case LOWPAN_IPHC_DAM_11:
242 /* 11: 8 bits. The address takes
243 * the form ff02::00XX.
244 */
245 ipaddr->s6_addr[0] = 0xFF;
246 ipaddr->s6_addr[1] = 0x02;
247 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
248 break;
249 default:
250 pr_debug("DAM value has a wrong value: 0x%x\n", dam);
251 return -EINVAL;
252 }
253
254 if (fail) {
255 pr_debug("Failed to fetch skb data\n");
256 return -EIO;
257 }
258
259 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
260 ipaddr->s6_addr, 16);
261
262 return 0;
263}
264
265static int
266uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
267{
268 bool fail;
269 u8 tmp = 0, val = 0;
270
271 if (!uh)
272 goto err;
273
274 fail = lowpan_fetch_skb(skb, &tmp, 1);
275
276 if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
277 pr_debug("UDP header uncompression\n");
278 switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
279 case LOWPAN_NHC_UDP_CS_P_00:
280 fail |= lowpan_fetch_skb(skb, &uh->source, 2);
281 fail |= lowpan_fetch_skb(skb, &uh->dest, 2);
282 break;
283 case LOWPAN_NHC_UDP_CS_P_01:
284 fail |= lowpan_fetch_skb(skb, &uh->source, 2);
285 fail |= lowpan_fetch_skb(skb, &val, 1);
286 uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
287 break;
288 case LOWPAN_NHC_UDP_CS_P_10:
289 fail |= lowpan_fetch_skb(skb, &val, 1);
290 uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
291 fail |= lowpan_fetch_skb(skb, &uh->dest, 2);
292 break;
293 case LOWPAN_NHC_UDP_CS_P_11:
294 fail |= lowpan_fetch_skb(skb, &val, 1);
295 uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT +
296 (val >> 4));
297 uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT +
298 (val & 0x0f));
299 break;
300 default:
301 pr_debug("ERROR: unknown UDP format\n");
302 goto err;
303 break;
304 }
305
306 pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
307 ntohs(uh->source), ntohs(uh->dest));
308
309 /* checksum */
310 if (tmp & LOWPAN_NHC_UDP_CS_C) {
311 pr_debug_ratelimited("checksum elided currently not supported\n");
312 goto err;
313 } else {
314 fail |= lowpan_fetch_skb(skb, &uh->check, 2);
315 }
316
317 /*
318 * UDP lenght needs to be infered from the lower layers
319 * here, we obtain the hint from the remaining size of the
320 * frame
321 */
322 uh->len = htons(skb->len + sizeof(struct udphdr));
323 pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len));
324 } else {
325 pr_debug("ERROR: unsupported NH format\n");
326 goto err;
327 }
328
329 if (fail)
330 goto err;
331
332 return 0;
333err:
334 return -EINVAL;
335}
336
337/* TTL uncompression values */
338static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
339
340int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
341 const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
342 const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
343 u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
344{
345 struct ipv6hdr hdr = {};
346 u8 tmp, num_context = 0;
347 int err;
348
349 raw_dump_table(__func__, "raw skb data dump uncompressed",
350 skb->data, skb->len);
351
352 /* another if the CID flag is set */
353 if (iphc1 & LOWPAN_IPHC_CID) {
354 pr_debug("CID flag is set, increase header with one\n");
355 if (lowpan_fetch_skb_u8(skb, &num_context))
356 goto drop;
357 }
358
359 hdr.version = 6;
360
361 /* Traffic Class and Flow Label */
362 switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
363 /*
364 * Traffic Class and FLow Label carried in-line
365 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
366 */
367 case 0: /* 00b */
368 if (lowpan_fetch_skb_u8(skb, &tmp))
369 goto drop;
370
371 memcpy(&hdr.flow_lbl, &skb->data[0], 3);
372 skb_pull(skb, 3);
373 hdr.priority = ((tmp >> 2) & 0x0f);
374 hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
375 (hdr.flow_lbl[0] & 0x0f);
376 break;
377 /*
378 * Traffic class carried in-line
379 * ECN + DSCP (1 byte), Flow Label is elided
380 */
381 case 2: /* 10b */
382 if (lowpan_fetch_skb_u8(skb, &tmp))
383 goto drop;
384
385 hdr.priority = ((tmp >> 2) & 0x0f);
386 hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
387 break;
388 /*
389 * Flow Label carried in-line
390 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
391 */
392 case 1: /* 01b */
393 if (lowpan_fetch_skb_u8(skb, &tmp))
394 goto drop;
395
396 hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
397 memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
398 skb_pull(skb, 2);
399 break;
400 /* Traffic Class and Flow Label are elided */
401 case 3: /* 11b */
402 break;
403 default:
404 break;
405 }
406
407 /* Next Header */
408 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
409 /* Next header is carried inline */
410 if (lowpan_fetch_skb_u8(skb, &(hdr.nexthdr)))
411 goto drop;
412
413 pr_debug("NH flag is set, next header carried inline: %02x\n",
414 hdr.nexthdr);
415 }
416
417 /* Hop Limit */
418 if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I)
419 hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
420 else {
421 if (lowpan_fetch_skb_u8(skb, &(hdr.hop_limit)))
422 goto drop;
423 }
424
425 /* Extract SAM to the tmp variable */
426 tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
427
428 if (iphc1 & LOWPAN_IPHC_SAC) {
429 /* Source address context based uncompression */
430 pr_debug("SAC bit is set. Handle context based source address.\n");
431 err = uncompress_context_based_src_addr(
432 skb, &hdr.saddr, tmp);
433 } else {
434 /* Source address uncompression */
435 pr_debug("source address stateless compression\n");
436 err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
437 saddr_type, saddr_len);
438 }
439
440 /* Check on error of previous branch */
441 if (err)
442 goto drop;
443
444 /* Extract DAM to the tmp variable */
445 tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
446
447 /* check for Multicast Compression */
448 if (iphc1 & LOWPAN_IPHC_M) {
449 if (iphc1 & LOWPAN_IPHC_DAC) {
450 pr_debug("dest: context-based mcast compression\n");
451 /* TODO: implement this */
452 } else {
453 err = lowpan_uncompress_multicast_daddr(
454 skb, &hdr.daddr, tmp);
455 if (err)
456 goto drop;
457 }
458 } else {
459 err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
460 daddr_type, daddr_len);
461 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
462 tmp, &hdr.daddr);
463 if (err)
464 goto drop;
465 }
466
467 /* UDP data uncompression */
468 if (iphc0 & LOWPAN_IPHC_NH_C) {
469 struct udphdr uh;
470 struct sk_buff *new;
471 if (uncompress_udp_header(skb, &uh))
472 goto drop;
473
474 /*
475 * replace the compressed UDP head by the uncompressed UDP
476 * header
477 */
478 new = skb_copy_expand(skb, sizeof(struct udphdr),
479 skb_tailroom(skb), GFP_ATOMIC);
480 kfree_skb(skb);
481
482 if (!new)
483 return -ENOMEM;
484
485 skb = new;
486
487 skb_push(skb, sizeof(struct udphdr));
488 skb_reset_transport_header(skb);
489 skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
490
491 raw_dump_table(__func__, "raw UDP header dump",
492 (u8 *)&uh, sizeof(uh));
493
494 hdr.nexthdr = UIP_PROTO_UDP;
495 }
496
497 hdr.payload_len = htons(skb->len);
498
499 pr_debug("skb headroom size = %d, data length = %d\n",
500 skb_headroom(skb), skb->len);
501
502 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
503 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
504 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
505 hdr.hop_limit, &hdr.daddr);
506
507 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr,
508 sizeof(hdr));
509
510 return skb_deliver(skb, &hdr, dev, deliver_skb);
511
512drop:
513 kfree_skb(skb);
514 return -EINVAL;
515}
516EXPORT_SYMBOL_GPL(lowpan_process_data);
517
518static u8 lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift,
519 const struct in6_addr *ipaddr,
520 const unsigned char *lladdr)
521{
522 u8 val = 0;
523
524 if (is_addr_mac_addr_based(ipaddr, lladdr)) {
525 val = 3; /* 0-bits */
526 pr_debug("address compression 0 bits\n");
527 } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
528 /* compress IID to 16 bits xxxx::XXXX */
529 memcpy(*hc06_ptr, &ipaddr->s6_addr16[7], 2);
530 *hc06_ptr += 2;
531 val = 2; /* 16-bits */
532 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
533 *hc06_ptr - 2, 2);
534 } else {
535 /* do not compress IID => xxxx::IID */
536 memcpy(*hc06_ptr, &ipaddr->s6_addr16[4], 8);
537 *hc06_ptr += 8;
538 val = 1; /* 64-bits */
539 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
540 *hc06_ptr - 8, 8);
541 }
542
543 return rol8(val, shift);
544}
545
546static void compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)
547{
548 struct udphdr *uh = udp_hdr(skb);
549 u8 tmp;
550
551 if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) ==
552 LOWPAN_NHC_UDP_4BIT_PORT) &&
553 ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) ==
554 LOWPAN_NHC_UDP_4BIT_PORT)) {
555 pr_debug("UDP header: both ports compression to 4 bits\n");
556 /* compression value */
557 tmp = LOWPAN_NHC_UDP_CS_P_11;
558 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
559 /* source and destination port */
560 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT +
561 ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4);
562 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
563 } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) ==
564 LOWPAN_NHC_UDP_8BIT_PORT) {
565 pr_debug("UDP header: remove 8 bits of dest\n");
566 /* compression value */
567 tmp = LOWPAN_NHC_UDP_CS_P_01;
568 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
569 /* source port */
570 lowpan_push_hc_data(hc06_ptr, &uh->source, sizeof(uh->source));
571 /* destination port */
572 tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT;
573 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
574 } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) ==
575 LOWPAN_NHC_UDP_8BIT_PORT) {
576 pr_debug("UDP header: remove 8 bits of source\n");
577 /* compression value */
578 tmp = LOWPAN_NHC_UDP_CS_P_10;
579 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
580 /* source port */
581 tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT;
582 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
583 /* destination port */
584 lowpan_push_hc_data(hc06_ptr, &uh->dest, sizeof(uh->dest));
585 } else {
586 pr_debug("UDP header: can't compress\n");
587 /* compression value */
588 tmp = LOWPAN_NHC_UDP_CS_P_00;
589 lowpan_push_hc_data(hc06_ptr, &tmp, sizeof(tmp));
590 /* source port */
591 lowpan_push_hc_data(hc06_ptr, &uh->source, sizeof(uh->source));
592 /* destination port */
593 lowpan_push_hc_data(hc06_ptr, &uh->dest, sizeof(uh->dest));
594 }
595
596 /* checksum is always inline */
597 lowpan_push_hc_data(hc06_ptr, &uh->check, sizeof(uh->check));
598
599 /* skip the UDP header */
600 skb_pull(skb, sizeof(struct udphdr));
601}
602
603int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
604 unsigned short type, const void *_daddr,
605 const void *_saddr, unsigned int len)
606{
607 u8 tmp, iphc0, iphc1, *hc06_ptr;
608 struct ipv6hdr *hdr;
609 u8 head[100] = {};
610
611 if (type != ETH_P_IPV6)
612 return -EINVAL;
613
614 hdr = ipv6_hdr(skb);
615 hc06_ptr = head + 2;
616
617 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
618 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
619 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
620 hdr->hop_limit, &hdr->daddr);
621
622 raw_dump_table(__func__, "raw skb network header dump",
623 skb_network_header(skb), sizeof(struct ipv6hdr));
624
625 /*
626 * As we copy some bit-length fields, in the IPHC encoding bytes,
627 * we sometimes use |=
628 * If the field is 0, and the current bit value in memory is 1,
629 * this does not work. We therefore reset the IPHC encoding here
630 */
631 iphc0 = LOWPAN_DISPATCH_IPHC;
632 iphc1 = 0;
633
634 /* TODO: context lookup */
635
636 raw_dump_inline(__func__, "saddr",
637 (unsigned char *)_saddr, IEEE802154_ADDR_LEN);
638 raw_dump_inline(__func__, "daddr",
639 (unsigned char *)_daddr, IEEE802154_ADDR_LEN);
640
641 raw_dump_table(__func__,
642 "sending raw skb network uncompressed packet",
643 skb->data, skb->len);
644
645 /*
646 * Traffic class, flow label
647 * If flow label is 0, compress it. If traffic class is 0, compress it
648 * We have to process both in the same time as the offset of traffic
649 * class depends on the presence of version and flow label
650 */
651
652 /* hc06 format of TC is ECN | DSCP , original one is DSCP | ECN */
653 tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
654 tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
655
656 if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
657 (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
658 /* flow label can be compressed */
659 iphc0 |= LOWPAN_IPHC_FL_C;
660 if ((hdr->priority == 0) &&
661 ((hdr->flow_lbl[0] & 0xF0) == 0)) {
662 /* compress (elide) all */
663 iphc0 |= LOWPAN_IPHC_TC_C;
664 } else {
665 /* compress only the flow label */
666 *hc06_ptr = tmp;
667 hc06_ptr += 1;
668 }
669 } else {
670 /* Flow label cannot be compressed */
671 if ((hdr->priority == 0) &&
672 ((hdr->flow_lbl[0] & 0xF0) == 0)) {
673 /* compress only traffic class */
674 iphc0 |= LOWPAN_IPHC_TC_C;
675 *hc06_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
676 memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2);
677 hc06_ptr += 3;
678 } else {
679 /* compress nothing */
680 memcpy(hc06_ptr, hdr, 4);
681 /* replace the top byte with new ECN | DSCP format */
682 *hc06_ptr = tmp;
683 hc06_ptr += 4;
684 }
685 }
686
687 /* NOTE: payload length is always compressed */
688
689 /* Next Header is compress if UDP */
690 if (hdr->nexthdr == UIP_PROTO_UDP)
691 iphc0 |= LOWPAN_IPHC_NH_C;
692
693 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
694 *hc06_ptr = hdr->nexthdr;
695 hc06_ptr += 1;
696 }
697
698 /*
699 * Hop limit
700 * if 1: compress, encoding is 01
701 * if 64: compress, encoding is 10
702 * if 255: compress, encoding is 11
703 * else do not compress
704 */
705 switch (hdr->hop_limit) {
706 case 1:
707 iphc0 |= LOWPAN_IPHC_TTL_1;
708 break;
709 case 64:
710 iphc0 |= LOWPAN_IPHC_TTL_64;
711 break;
712 case 255:
713 iphc0 |= LOWPAN_IPHC_TTL_255;
714 break;
715 default:
716 *hc06_ptr = hdr->hop_limit;
717 hc06_ptr += 1;
718 break;
719 }
720
721 /* source address compression */
722 if (is_addr_unspecified(&hdr->saddr)) {
723 pr_debug("source address is unspecified, setting SAC\n");
724 iphc1 |= LOWPAN_IPHC_SAC;
725 /* TODO: context lookup */
726 } else if (is_addr_link_local(&hdr->saddr)) {
727 iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
728 LOWPAN_IPHC_SAM_BIT, &hdr->saddr, _saddr);
729 pr_debug("source address unicast link-local %pI6c "
730 "iphc1 0x%02x\n", &hdr->saddr, iphc1);
731 } else {
732 pr_debug("send the full source address\n");
733 memcpy(hc06_ptr, &hdr->saddr.s6_addr16[0], 16);
734 hc06_ptr += 16;
735 }
736
737 /* destination address compression */
738 if (is_addr_mcast(&hdr->daddr)) {
739 pr_debug("destination address is multicast: ");
740 iphc1 |= LOWPAN_IPHC_M;
741 if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
742 pr_debug("compressed to 1 octet\n");
743 iphc1 |= LOWPAN_IPHC_DAM_11;
744 /* use last byte */
745 *hc06_ptr = hdr->daddr.s6_addr[15];
746 hc06_ptr += 1;
747 } else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
748 pr_debug("compressed to 4 octets\n");
749 iphc1 |= LOWPAN_IPHC_DAM_10;
750 /* second byte + the last three */
751 *hc06_ptr = hdr->daddr.s6_addr[1];
752 memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[13], 3);
753 hc06_ptr += 4;
754 } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
755 pr_debug("compressed to 6 octets\n");
756 iphc1 |= LOWPAN_IPHC_DAM_01;
757 /* second byte + the last five */
758 *hc06_ptr = hdr->daddr.s6_addr[1];
759 memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[11], 5);
760 hc06_ptr += 6;
761 } else {
762 pr_debug("using full address\n");
763 iphc1 |= LOWPAN_IPHC_DAM_00;
764 memcpy(hc06_ptr, &hdr->daddr.s6_addr[0], 16);
765 hc06_ptr += 16;
766 }
767 } else {
768 /* TODO: context lookup */
769 if (is_addr_link_local(&hdr->daddr)) {
770 iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
771 LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr);
772 pr_debug("dest address unicast link-local %pI6c "
773 "iphc1 0x%02x\n", &hdr->daddr, iphc1);
774 } else {
775 pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
776 memcpy(hc06_ptr, &hdr->daddr.s6_addr16[0], 16);
777 hc06_ptr += 16;
778 }
779 }
780
781 /* UDP header compression */
782 if (hdr->nexthdr == UIP_PROTO_UDP)
783 compress_udp_header(&hc06_ptr, skb);
784
785 head[0] = iphc0;
786 head[1] = iphc1;
787
788 skb_pull(skb, sizeof(struct ipv6hdr));
789 skb_reset_transport_header(skb);
790 memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);
791 skb_reset_network_header(skb);
792
793 pr_debug("header len %d skb %u\n", (int)(hc06_ptr - head), skb->len);
794
795 raw_dump_table(__func__, "raw skb data dump compressed",
796 skb->data, skb->len);
797 return 0;
798}
799EXPORT_SYMBOL_GPL(lowpan_header_compress);
800
801MODULE_LICENSE("GPL");
generated by cgit v1.2.2 (git 2.25.0) at 2025-03-04 15:15:40 -0500