2 * Copyright 2011, Siemens AG
3 * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
6 /* Based on patches from Jon Smirl <jonsmirl@gmail.com>
7 * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
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.
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.
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.
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
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.
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
49 #include <linux/bitops.h>
50 #include <linux/if_arp.h>
51 #include <linux/netdevice.h>
52 #include <net/6lowpan.h>
54 #include <net/af_ieee802154.h>
58 /* Uncompress address function for source and
59 * destination address(non-multicast).
61 * address_mode is sam value or dam value.
63 static int uncompress_addr(struct sk_buff *skb,
64 struct in6_addr *ipaddr, const u8 address_mode,
65 const u8 *lladdr, const u8 addr_type,
70 switch (address_mode) {
71 case LOWPAN_IPHC_ADDR_00:
72 /* for global link addresses */
73 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
75 case LOWPAN_IPHC_ADDR_01:
76 /* fe:80::XXXX:XXXX:XXXX:XXXX */
77 ipaddr->s6_addr[0] = 0xFE;
78 ipaddr->s6_addr[1] = 0x80;
79 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
81 case LOWPAN_IPHC_ADDR_02:
82 /* fe:80::ff:fe00:XXXX */
83 ipaddr->s6_addr[0] = 0xFE;
84 ipaddr->s6_addr[1] = 0x80;
85 ipaddr->s6_addr[11] = 0xFF;
86 ipaddr->s6_addr[12] = 0xFE;
87 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
89 case LOWPAN_IPHC_ADDR_03:
92 case IEEE802154_ADDR_LONG:
93 /* fe:80::XXXX:XXXX:XXXX:XXXX
97 ipaddr->s6_addr[0] = 0xFE;
98 ipaddr->s6_addr[1] = 0x80;
99 memcpy(&ipaddr->s6_addr[8], lladdr, addr_len);
100 /* second bit-flip (Universe/Local)
101 * is done according RFC2464
103 ipaddr->s6_addr[8] ^= 0x02;
105 case IEEE802154_ADDR_SHORT:
106 /* fe:80::ff:fe00:XXXX
110 * Universe/Local bit is zero.
112 ipaddr->s6_addr[0] = 0xFE;
113 ipaddr->s6_addr[1] = 0x80;
114 ipaddr->s6_addr[11] = 0xFF;
115 ipaddr->s6_addr[12] = 0xFE;
116 ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr));
119 pr_debug("Invalid addr_type set\n");
124 pr_debug("Invalid address mode value: 0x%x\n", address_mode);
129 pr_debug("Failed to fetch skb data\n");
133 raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
134 ipaddr->s6_addr, 16);
139 /* Uncompress address function for source context
140 * based address(non-multicast).
142 static int uncompress_context_based_src_addr(struct sk_buff *skb,
143 struct in6_addr *ipaddr,
147 case LOWPAN_IPHC_ADDR_00:
149 * Do nothing, address is already ::
152 case LOWPAN_IPHC_ADDR_01:
154 case LOWPAN_IPHC_ADDR_02:
156 case LOWPAN_IPHC_ADDR_03:
158 netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
161 pr_debug("Invalid sam value: 0x%x\n", sam);
165 raw_dump_inline(NULL,
166 "Reconstructed context based ipv6 src addr is",
167 ipaddr->s6_addr, 16);
172 /* Uncompress function for multicast destination address,
175 static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
176 struct in6_addr *ipaddr,
182 case LOWPAN_IPHC_DAM_00:
183 /* 00: 128 bits. The full address
184 * is carried in-line.
186 fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
188 case LOWPAN_IPHC_DAM_01:
189 /* 01: 48 bits. The address takes
190 * the form ffXX::00XX:XXXX:XXXX.
192 ipaddr->s6_addr[0] = 0xFF;
193 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
194 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
196 case LOWPAN_IPHC_DAM_10:
197 /* 10: 32 bits. The address takes
198 * the form ffXX::00XX:XXXX.
200 ipaddr->s6_addr[0] = 0xFF;
201 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
202 fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
204 case LOWPAN_IPHC_DAM_11:
205 /* 11: 8 bits. The address takes
206 * the form ff02::00XX.
208 ipaddr->s6_addr[0] = 0xFF;
209 ipaddr->s6_addr[1] = 0x02;
210 fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
213 pr_debug("DAM value has a wrong value: 0x%x\n", dam);
218 pr_debug("Failed to fetch skb data\n");
222 raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
223 ipaddr->s6_addr, 16);
228 /* TTL uncompression values */
229 static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
232 lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
233 const u8 *saddr, const u8 saddr_type,
234 const u8 saddr_len, const u8 *daddr,
235 const u8 daddr_type, const u8 daddr_len,
238 struct ipv6hdr hdr = {};
239 u8 tmp, num_context = 0;
242 raw_dump_table(__func__, "raw skb data dump uncompressed",
243 skb->data, skb->len);
245 /* another if the CID flag is set */
246 if (iphc1 & LOWPAN_IPHC_CID) {
247 pr_debug("CID flag is set, increase header with one\n");
248 if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context)))
254 /* Traffic Class and Flow Label */
255 switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
256 /* Traffic Class and FLow Label carried in-line
257 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
260 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
263 memcpy(&hdr.flow_lbl, &skb->data[0], 3);
265 hdr.priority = ((tmp >> 2) & 0x0f);
266 hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
267 (hdr.flow_lbl[0] & 0x0f);
269 /* Traffic class carried in-line
270 * ECN + DSCP (1 byte), Flow Label is elided
273 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
276 hdr.priority = ((tmp >> 2) & 0x0f);
277 hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
279 /* Flow Label carried in-line
280 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
283 if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
286 hdr.flow_lbl[0] = (tmp & 0x0F) | ((tmp >> 2) & 0x30);
287 memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
290 /* Traffic Class and Flow Label are elided */
298 if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
299 /* Next header is carried inline */
300 if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
303 pr_debug("NH flag is set, next header carried inline: %02x\n",
308 if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) {
309 hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
311 if (lowpan_fetch_skb(skb, &hdr.hop_limit,
312 sizeof(hdr.hop_limit)))
316 /* Extract SAM to the tmp variable */
317 tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
319 if (iphc1 & LOWPAN_IPHC_SAC) {
320 /* Source address context based uncompression */
321 pr_debug("SAC bit is set. Handle context based source address.\n");
322 err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp);
324 /* Source address uncompression */
325 pr_debug("source address stateless compression\n");
326 err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
327 saddr_type, saddr_len);
330 /* Check on error of previous branch */
334 /* Extract DAM to the tmp variable */
335 tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
337 /* check for Multicast Compression */
338 if (iphc1 & LOWPAN_IPHC_M) {
339 if (iphc1 & LOWPAN_IPHC_DAC) {
340 pr_debug("dest: context-based mcast compression\n");
341 /* TODO: implement this */
343 err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
350 err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
351 daddr_type, daddr_len);
352 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
358 /* Next header data uncompression */
359 if (iphc0 & LOWPAN_IPHC_NH_C) {
360 err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
364 err = skb_cow(skb, sizeof(hdr));
369 switch (lowpan_priv(dev)->lltype) {
370 case LOWPAN_LLTYPE_IEEE802154:
371 if (lowpan_802154_cb(skb)->d_size)
372 hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
373 sizeof(struct ipv6hdr));
375 hdr.payload_len = htons(skb->len);
378 hdr.payload_len = htons(skb->len);
382 pr_debug("skb headroom size = %d, data length = %d\n",
383 skb_headroom(skb), skb->len);
385 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
386 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
387 hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
388 hdr.hop_limit, &hdr.daddr);
390 skb_push(skb, sizeof(hdr));
391 skb_reset_network_header(skb);
392 skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
394 raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
398 EXPORT_SYMBOL_GPL(lowpan_header_decompress);
400 static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift,
401 const struct in6_addr *ipaddr,
402 const unsigned char *lladdr)
406 if (is_addr_mac_addr_based(ipaddr, lladdr)) {
407 val = 3; /* 0-bits */
408 pr_debug("address compression 0 bits\n");
409 } else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
410 /* compress IID to 16 bits xxxx::XXXX */
411 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
412 val = 2; /* 16-bits */
413 raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
416 /* do not compress IID => xxxx::IID */
417 lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
418 val = 1; /* 64-bits */
419 raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
423 return rol8(val, shift);
426 int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
427 const void *daddr, const void *saddr)
429 u8 tmp, iphc0, iphc1, *hc_ptr;
431 u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
434 if (skb->protocol != htons(ETH_P_IPV6))
440 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
441 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
442 hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
443 hdr->hop_limit, &hdr->daddr);
445 raw_dump_table(__func__, "raw skb network header dump",
446 skb_network_header(skb), sizeof(struct ipv6hdr));
448 /* As we copy some bit-length fields, in the IPHC encoding bytes,
449 * we sometimes use |=
450 * If the field is 0, and the current bit value in memory is 1,
451 * this does not work. We therefore reset the IPHC encoding here
453 iphc0 = LOWPAN_DISPATCH_IPHC;
456 /* TODO: context lookup */
458 raw_dump_inline(__func__, "saddr", saddr, EUI64_ADDR_LEN);
459 raw_dump_inline(__func__, "daddr", daddr, EUI64_ADDR_LEN);
461 raw_dump_table(__func__, "sending raw skb network uncompressed packet",
462 skb->data, skb->len);
464 /* Traffic class, flow label
465 * If flow label is 0, compress it. If traffic class is 0, compress it
466 * We have to process both in the same time as the offset of traffic
467 * class depends on the presence of version and flow label
470 /* hc format of TC is ECN | DSCP , original one is DSCP | ECN */
471 tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
472 tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
474 if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
475 (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
476 /* flow label can be compressed */
477 iphc0 |= LOWPAN_IPHC_FL_C;
478 if ((hdr->priority == 0) &&
479 ((hdr->flow_lbl[0] & 0xF0) == 0)) {
480 /* compress (elide) all */
481 iphc0 |= LOWPAN_IPHC_TC_C;
483 /* compress only the flow label */
488 /* Flow label cannot be compressed */
489 if ((hdr->priority == 0) &&
490 ((hdr->flow_lbl[0] & 0xF0) == 0)) {
491 /* compress only traffic class */
492 iphc0 |= LOWPAN_IPHC_TC_C;
493 *hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
494 memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2);
497 /* compress nothing */
498 memcpy(hc_ptr, hdr, 4);
499 /* replace the top byte with new ECN | DSCP format */
505 /* NOTE: payload length is always compressed */
507 /* Check if we provide the nhc format for nexthdr and compression
508 * functionality. If not nexthdr is handled inline and not compressed.
510 ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr, &iphc0);
515 * if 1: compress, encoding is 01
516 * if 64: compress, encoding is 10
517 * if 255: compress, encoding is 11
518 * else do not compress
520 switch (hdr->hop_limit) {
522 iphc0 |= LOWPAN_IPHC_TTL_1;
525 iphc0 |= LOWPAN_IPHC_TTL_64;
528 iphc0 |= LOWPAN_IPHC_TTL_255;
531 lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
532 sizeof(hdr->hop_limit));
535 addr_type = ipv6_addr_type(&hdr->saddr);
536 /* source address compression */
537 if (addr_type == IPV6_ADDR_ANY) {
538 pr_debug("source address is unspecified, setting SAC\n");
539 iphc1 |= LOWPAN_IPHC_SAC;
541 if (addr_type & IPV6_ADDR_LINKLOCAL) {
542 iphc1 |= lowpan_compress_addr_64(&hc_ptr,
545 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
548 pr_debug("send the full source address\n");
549 lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16);
553 addr_type = ipv6_addr_type(&hdr->daddr);
554 /* destination address compression */
555 if (addr_type & IPV6_ADDR_MULTICAST) {
556 pr_debug("destination address is multicast: ");
557 iphc1 |= LOWPAN_IPHC_M;
558 if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
559 pr_debug("compressed to 1 octet\n");
560 iphc1 |= LOWPAN_IPHC_DAM_11;
562 lowpan_push_hc_data(&hc_ptr,
563 &hdr->daddr.s6_addr[15], 1);
564 } else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
565 pr_debug("compressed to 4 octets\n");
566 iphc1 |= LOWPAN_IPHC_DAM_10;
567 /* second byte + the last three */
568 lowpan_push_hc_data(&hc_ptr,
569 &hdr->daddr.s6_addr[1], 1);
570 lowpan_push_hc_data(&hc_ptr,
571 &hdr->daddr.s6_addr[13], 3);
572 } else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
573 pr_debug("compressed to 6 octets\n");
574 iphc1 |= LOWPAN_IPHC_DAM_01;
575 /* second byte + the last five */
576 lowpan_push_hc_data(&hc_ptr,
577 &hdr->daddr.s6_addr[1], 1);
578 lowpan_push_hc_data(&hc_ptr,
579 &hdr->daddr.s6_addr[11], 5);
581 pr_debug("using full address\n");
582 iphc1 |= LOWPAN_IPHC_DAM_00;
583 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
586 if (addr_type & IPV6_ADDR_LINKLOCAL) {
587 /* TODO: context lookup */
588 iphc1 |= lowpan_compress_addr_64(&hc_ptr,
589 LOWPAN_IPHC_DAM_BIT, &hdr->daddr, daddr);
590 pr_debug("dest address unicast link-local %pI6c "
591 "iphc1 0x%02x\n", &hdr->daddr, iphc1);
593 pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
594 lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
598 /* next header compression */
599 if (iphc0 & LOWPAN_IPHC_NH_C) {
600 ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
608 skb_pull(skb, sizeof(struct ipv6hdr));
609 skb_reset_transport_header(skb);
610 memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
611 skb_reset_network_header(skb);
613 pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
615 raw_dump_table(__func__, "raw skb data dump compressed",
616 skb->data, skb->len);
619 EXPORT_SYMBOL_GPL(lowpan_header_compress);