2 * Copyright 2011, Siemens AG
3 * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
7 * Based on patches from Jon Smirl <jonsmirl@gmail.com>
8 * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
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.
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.
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.
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.
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
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.
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
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>
59 #include <net/af_ieee802154.h>
62 * Uncompress address function for source and
63 * destination address(non-multicast).
65 * address_mode is sam value or dam value.
67 static int uncompress_addr(struct sk_buff
*skb
,
68 struct in6_addr
*ipaddr
, const u8 address_mode
,
69 const u8
*lladdr
, const u8 addr_type
,
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);
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);
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);
93 case LOWPAN_IPHC_ADDR_03
:
96 case IEEE802154_ADDR_LONG
:
97 /* fe:80::XXXX:XXXX:XXXX:XXXX
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
107 ipaddr
->s6_addr
[8] ^= 0x02;
109 case IEEE802154_ADDR_SHORT
:
110 /* fe:80::ff:fe00:XXXX
114 * Universe/Local bit is zero.
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
));
123 pr_debug("Invalid addr_type set\n");
128 pr_debug("Invalid address mode value: 0x%x\n", address_mode
);
133 pr_debug("Failed to fetch skb data\n");
137 raw_dump_inline(NULL
, "Reconstructed ipv6 addr is",
138 ipaddr
->s6_addr
, 16);
144 * Uncompress address function for source context
145 * based address(non-multicast).
147 static int uncompress_context_based_src_addr(struct sk_buff
*skb
,
148 struct in6_addr
*ipaddr
,
152 case LOWPAN_IPHC_ADDR_00
:
154 * Do nothing, address is already ::
157 case LOWPAN_IPHC_ADDR_01
:
159 case LOWPAN_IPHC_ADDR_02
:
161 case LOWPAN_IPHC_ADDR_03
:
163 netdev_warn(skb
->dev
, "SAM value 0x%x not supported\n", sam
);
166 pr_debug("Invalid sam value: 0x%x\n", sam
);
170 raw_dump_inline(NULL
,
171 "Reconstructed context based ipv6 src addr is",
172 ipaddr
->s6_addr
, 16);
177 static int skb_deliver(struct sk_buff
*skb
, struct ipv6hdr
*hdr
,
178 struct net_device
*dev
, skb_delivery_cb deliver_skb
)
183 new = skb_copy_expand(skb
, sizeof(struct ipv6hdr
), skb_tailroom(skb
),
190 skb_push(new, sizeof(struct ipv6hdr
));
191 skb_reset_network_header(new);
192 skb_copy_to_linear_data(new, hdr
, sizeof(struct ipv6hdr
));
194 new->protocol
= htons(ETH_P_IPV6
);
195 new->pkt_type
= PACKET_HOST
;
198 raw_dump_table(__func__
, "raw skb data dump before receiving",
199 new->data
, new->len
);
201 stat
= deliver_skb(new, dev
);
208 /* Uncompress function for multicast destination address,
212 lowpan_uncompress_multicast_daddr(struct sk_buff
*skb
,
213 struct in6_addr
*ipaddr
,
219 case LOWPAN_IPHC_DAM_00
:
220 /* 00: 128 bits. The full address
221 * is carried in-line.
223 fail
= lowpan_fetch_skb(skb
, ipaddr
->s6_addr
, 16);
225 case LOWPAN_IPHC_DAM_01
:
226 /* 01: 48 bits. The address takes
227 * the form ffXX::00XX:XXXX:XXXX.
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);
233 case LOWPAN_IPHC_DAM_10
:
234 /* 10: 32 bits. The address takes
235 * the form ffXX::00XX:XXXX.
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);
241 case LOWPAN_IPHC_DAM_11
:
242 /* 11: 8 bits. The address takes
243 * the form ff02::00XX.
245 ipaddr
->s6_addr
[0] = 0xFF;
246 ipaddr
->s6_addr
[1] = 0x02;
247 fail
= lowpan_fetch_skb(skb
, &ipaddr
->s6_addr
[15], 1);
250 pr_debug("DAM value has a wrong value: 0x%x\n", dam
);
255 pr_debug("Failed to fetch skb data\n");
259 raw_dump_inline(NULL
, "Reconstructed ipv6 multicast addr is",
260 ipaddr
->s6_addr
, 16);
266 uncompress_udp_header(struct sk_buff
*skb
, struct udphdr
*uh
)
274 fail
= lowpan_fetch_skb(skb
, &tmp
, sizeof(tmp
));
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
,
282 fail
|= lowpan_fetch_skb(skb
, &uh
->dest
,
285 case LOWPAN_NHC_UDP_CS_P_01
:
286 fail
|= lowpan_fetch_skb(skb
, &uh
->source
,
288 fail
|= lowpan_fetch_skb(skb
, &val
, sizeof(val
));
289 uh
->dest
= htons(val
+ LOWPAN_NHC_UDP_8BIT_PORT
);
291 case LOWPAN_NHC_UDP_CS_P_10
:
292 fail
|= lowpan_fetch_skb(skb
, &val
, sizeof(val
));
293 uh
->source
= htons(val
+ LOWPAN_NHC_UDP_8BIT_PORT
);
294 fail
|= lowpan_fetch_skb(skb
, &uh
->dest
,
297 case LOWPAN_NHC_UDP_CS_P_11
:
298 fail
|= lowpan_fetch_skb(skb
, &val
, sizeof(val
));
299 uh
->source
= htons(LOWPAN_NHC_UDP_4BIT_PORT
+
301 uh
->dest
= htons(LOWPAN_NHC_UDP_4BIT_PORT
+
305 pr_debug("ERROR: unknown UDP format\n");
310 pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
311 ntohs(uh
->source
), ntohs(uh
->dest
));
314 if (tmp
& LOWPAN_NHC_UDP_CS_C
) {
315 pr_debug_ratelimited("checksum elided currently not supported\n");
318 fail
|= lowpan_fetch_skb(skb
, &uh
->check
,
323 * UDP lenght needs to be infered from the lower layers
324 * here, we obtain the hint from the remaining size of the
327 uh
->len
= htons(skb
->len
+ sizeof(struct udphdr
));
328 pr_debug("uncompressed UDP length: src = %d", ntohs(uh
->len
));
330 pr_debug("ERROR: unsupported NH format\n");
342 /* TTL uncompression values */
343 static const u8 lowpan_ttl_values
[] = { 0, 1, 64, 255 };
345 int lowpan_process_data(struct sk_buff
*skb
, struct net_device
*dev
,
346 const u8
*saddr
, const u8 saddr_type
, const u8 saddr_len
,
347 const u8
*daddr
, const u8 daddr_type
, const u8 daddr_len
,
348 u8 iphc0
, u8 iphc1
, skb_delivery_cb deliver_skb
)
350 struct ipv6hdr hdr
= {};
351 u8 tmp
, num_context
= 0;
354 raw_dump_table(__func__
, "raw skb data dump uncompressed",
355 skb
->data
, skb
->len
);
357 /* another if the CID flag is set */
358 if (iphc1
& LOWPAN_IPHC_CID
) {
359 pr_debug("CID flag is set, increase header with one\n");
360 if (lowpan_fetch_skb(skb
, &num_context
, sizeof(num_context
)))
366 /* Traffic Class and Flow Label */
367 switch ((iphc0
& LOWPAN_IPHC_TF
) >> 3) {
369 * Traffic Class and FLow Label carried in-line
370 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
373 if (lowpan_fetch_skb(skb
, &tmp
, sizeof(tmp
)))
376 memcpy(&hdr
.flow_lbl
, &skb
->data
[0], 3);
378 hdr
.priority
= ((tmp
>> 2) & 0x0f);
379 hdr
.flow_lbl
[0] = ((tmp
>> 2) & 0x30) | (tmp
<< 6) |
380 (hdr
.flow_lbl
[0] & 0x0f);
383 * Traffic class carried in-line
384 * ECN + DSCP (1 byte), Flow Label is elided
387 if (lowpan_fetch_skb(skb
, &tmp
, sizeof(tmp
)))
390 hdr
.priority
= ((tmp
>> 2) & 0x0f);
391 hdr
.flow_lbl
[0] = ((tmp
<< 6) & 0xC0) | ((tmp
>> 2) & 0x30);
394 * Flow Label carried in-line
395 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
398 if (lowpan_fetch_skb(skb
, &tmp
, sizeof(tmp
)))
401 hdr
.flow_lbl
[0] = (skb
->data
[0] & 0x0F) | ((tmp
>> 2) & 0x30);
402 memcpy(&hdr
.flow_lbl
[1], &skb
->data
[0], 2);
405 /* Traffic Class and Flow Label are elided */
413 if ((iphc0
& LOWPAN_IPHC_NH_C
) == 0) {
414 /* Next header is carried inline */
415 if (lowpan_fetch_skb(skb
, &hdr
.nexthdr
, sizeof(hdr
.nexthdr
)))
418 pr_debug("NH flag is set, next header carried inline: %02x\n",
423 if ((iphc0
& 0x03) != LOWPAN_IPHC_TTL_I
)
424 hdr
.hop_limit
= lowpan_ttl_values
[iphc0
& 0x03];
426 if (lowpan_fetch_skb(skb
, &hdr
.hop_limit
,
427 sizeof(hdr
.hop_limit
)))
431 /* Extract SAM to the tmp variable */
432 tmp
= ((iphc1
& LOWPAN_IPHC_SAM
) >> LOWPAN_IPHC_SAM_BIT
) & 0x03;
434 if (iphc1
& LOWPAN_IPHC_SAC
) {
435 /* Source address context based uncompression */
436 pr_debug("SAC bit is set. Handle context based source address.\n");
437 err
= uncompress_context_based_src_addr(
438 skb
, &hdr
.saddr
, tmp
);
440 /* Source address uncompression */
441 pr_debug("source address stateless compression\n");
442 err
= uncompress_addr(skb
, &hdr
.saddr
, tmp
, saddr
,
443 saddr_type
, saddr_len
);
446 /* Check on error of previous branch */
450 /* Extract DAM to the tmp variable */
451 tmp
= ((iphc1
& LOWPAN_IPHC_DAM_11
) >> LOWPAN_IPHC_DAM_BIT
) & 0x03;
453 /* check for Multicast Compression */
454 if (iphc1
& LOWPAN_IPHC_M
) {
455 if (iphc1
& LOWPAN_IPHC_DAC
) {
456 pr_debug("dest: context-based mcast compression\n");
457 /* TODO: implement this */
459 err
= lowpan_uncompress_multicast_daddr(
460 skb
, &hdr
.daddr
, tmp
);
465 err
= uncompress_addr(skb
, &hdr
.daddr
, tmp
, daddr
,
466 daddr_type
, daddr_len
);
467 pr_debug("dest: stateless compression mode %d dest %pI6c\n",
473 /* UDP data uncompression */
474 if (iphc0
& LOWPAN_IPHC_NH_C
) {
477 if (uncompress_udp_header(skb
, &uh
))
481 * replace the compressed UDP head by the uncompressed UDP
484 new = skb_copy_expand(skb
, sizeof(struct udphdr
),
485 skb_tailroom(skb
), GFP_ATOMIC
);
493 skb_push(skb
, sizeof(struct udphdr
));
494 skb_reset_transport_header(skb
);
495 skb_copy_to_linear_data(skb
, &uh
, sizeof(struct udphdr
));
497 raw_dump_table(__func__
, "raw UDP header dump",
498 (u8
*)&uh
, sizeof(uh
));
500 hdr
.nexthdr
= UIP_PROTO_UDP
;
503 hdr
.payload_len
= htons(skb
->len
);
505 pr_debug("skb headroom size = %d, data length = %d\n",
506 skb_headroom(skb
), skb
->len
);
508 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
509 "nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
510 hdr
.version
, ntohs(hdr
.payload_len
), hdr
.nexthdr
,
511 hdr
.hop_limit
, &hdr
.daddr
);
513 raw_dump_table(__func__
, "raw header dump", (u8
*)&hdr
,
516 return skb_deliver(skb
, &hdr
, dev
, deliver_skb
);
522 EXPORT_SYMBOL_GPL(lowpan_process_data
);
524 static u8
lowpan_compress_addr_64(u8
**hc_ptr
, u8 shift
,
525 const struct in6_addr
*ipaddr
,
526 const unsigned char *lladdr
)
530 if (is_addr_mac_addr_based(ipaddr
, lladdr
)) {
531 val
= 3; /* 0-bits */
532 pr_debug("address compression 0 bits\n");
533 } else if (lowpan_is_iid_16_bit_compressable(ipaddr
)) {
534 /* compress IID to 16 bits xxxx::XXXX */
535 lowpan_push_hc_data(hc_ptr
, &ipaddr
->s6_addr16
[7], 2);
536 val
= 2; /* 16-bits */
537 raw_dump_inline(NULL
, "Compressed ipv6 addr is (16 bits)",
540 /* do not compress IID => xxxx::IID */
541 lowpan_push_hc_data(hc_ptr
, &ipaddr
->s6_addr16
[4], 8);
542 val
= 1; /* 64-bits */
543 raw_dump_inline(NULL
, "Compressed ipv6 addr is (64 bits)",
547 return rol8(val
, shift
);
550 static void compress_udp_header(u8
**hc_ptr
, struct sk_buff
*skb
)
552 struct udphdr
*uh
= udp_hdr(skb
);
555 if (((ntohs(uh
->source
) & LOWPAN_NHC_UDP_4BIT_MASK
) ==
556 LOWPAN_NHC_UDP_4BIT_PORT
) &&
557 ((ntohs(uh
->dest
) & LOWPAN_NHC_UDP_4BIT_MASK
) ==
558 LOWPAN_NHC_UDP_4BIT_PORT
)) {
559 pr_debug("UDP header: both ports compression to 4 bits\n");
560 /* compression value */
561 tmp
= LOWPAN_NHC_UDP_CS_P_11
;
562 lowpan_push_hc_data(hc_ptr
, &tmp
, sizeof(tmp
));
563 /* source and destination port */
564 tmp
= ntohs(uh
->dest
) - LOWPAN_NHC_UDP_4BIT_PORT
+
565 ((ntohs(uh
->source
) - LOWPAN_NHC_UDP_4BIT_PORT
) << 4);
566 lowpan_push_hc_data(hc_ptr
, &tmp
, sizeof(tmp
));
567 } else if ((ntohs(uh
->dest
) & LOWPAN_NHC_UDP_8BIT_MASK
) ==
568 LOWPAN_NHC_UDP_8BIT_PORT
) {
569 pr_debug("UDP header: remove 8 bits of dest\n");
570 /* compression value */
571 tmp
= LOWPAN_NHC_UDP_CS_P_01
;
572 lowpan_push_hc_data(hc_ptr
, &tmp
, sizeof(tmp
));
574 lowpan_push_hc_data(hc_ptr
, &uh
->source
, sizeof(uh
->source
));
575 /* destination port */
576 tmp
= ntohs(uh
->dest
) - LOWPAN_NHC_UDP_8BIT_PORT
;
577 lowpan_push_hc_data(hc_ptr
, &tmp
, sizeof(tmp
));
578 } else if ((ntohs(uh
->source
) & LOWPAN_NHC_UDP_8BIT_MASK
) ==
579 LOWPAN_NHC_UDP_8BIT_PORT
) {
580 pr_debug("UDP header: remove 8 bits of source\n");
581 /* compression value */
582 tmp
= LOWPAN_NHC_UDP_CS_P_10
;
583 lowpan_push_hc_data(hc_ptr
, &tmp
, sizeof(tmp
));
585 tmp
= ntohs(uh
->source
) - LOWPAN_NHC_UDP_8BIT_PORT
;
586 lowpan_push_hc_data(hc_ptr
, &tmp
, sizeof(tmp
));
587 /* destination port */
588 lowpan_push_hc_data(hc_ptr
, &uh
->dest
, sizeof(uh
->dest
));
590 pr_debug("UDP header: can't compress\n");
591 /* compression value */
592 tmp
= LOWPAN_NHC_UDP_CS_P_00
;
593 lowpan_push_hc_data(hc_ptr
, &tmp
, sizeof(tmp
));
595 lowpan_push_hc_data(hc_ptr
, &uh
->source
, sizeof(uh
->source
));
596 /* destination port */
597 lowpan_push_hc_data(hc_ptr
, &uh
->dest
, sizeof(uh
->dest
));
600 /* checksum is always inline */
601 lowpan_push_hc_data(hc_ptr
, &uh
->check
, sizeof(uh
->check
));
603 /* skip the UDP header */
604 skb_pull(skb
, sizeof(struct udphdr
));
607 int lowpan_header_compress(struct sk_buff
*skb
, struct net_device
*dev
,
608 unsigned short type
, const void *_daddr
,
609 const void *_saddr
, unsigned int len
)
611 u8 tmp
, iphc0
, iphc1
, *hc_ptr
;
616 if (type
!= ETH_P_IPV6
)
622 pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
623 "\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
624 hdr
->version
, ntohs(hdr
->payload_len
), hdr
->nexthdr
,
625 hdr
->hop_limit
, &hdr
->daddr
);
627 raw_dump_table(__func__
, "raw skb network header dump",
628 skb_network_header(skb
), sizeof(struct ipv6hdr
));
631 * As we copy some bit-length fields, in the IPHC encoding bytes,
632 * we sometimes use |=
633 * If the field is 0, and the current bit value in memory is 1,
634 * this does not work. We therefore reset the IPHC encoding here
636 iphc0
= LOWPAN_DISPATCH_IPHC
;
639 /* TODO: context lookup */
641 raw_dump_inline(__func__
, "saddr",
642 (unsigned char *)_saddr
, IEEE802154_ADDR_LEN
);
643 raw_dump_inline(__func__
, "daddr",
644 (unsigned char *)_daddr
, IEEE802154_ADDR_LEN
);
646 raw_dump_table(__func__
,
647 "sending raw skb network uncompressed packet",
648 skb
->data
, skb
->len
);
651 * Traffic class, flow label
652 * If flow label is 0, compress it. If traffic class is 0, compress it
653 * We have to process both in the same time as the offset of traffic
654 * class depends on the presence of version and flow label
657 /* hc format of TC is ECN | DSCP , original one is DSCP | ECN */
658 tmp
= (hdr
->priority
<< 4) | (hdr
->flow_lbl
[0] >> 4);
659 tmp
= ((tmp
& 0x03) << 6) | (tmp
>> 2);
661 if (((hdr
->flow_lbl
[0] & 0x0F) == 0) &&
662 (hdr
->flow_lbl
[1] == 0) && (hdr
->flow_lbl
[2] == 0)) {
663 /* flow label can be compressed */
664 iphc0
|= LOWPAN_IPHC_FL_C
;
665 if ((hdr
->priority
== 0) &&
666 ((hdr
->flow_lbl
[0] & 0xF0) == 0)) {
667 /* compress (elide) all */
668 iphc0
|= LOWPAN_IPHC_TC_C
;
670 /* compress only the flow label */
675 /* Flow label cannot be compressed */
676 if ((hdr
->priority
== 0) &&
677 ((hdr
->flow_lbl
[0] & 0xF0) == 0)) {
678 /* compress only traffic class */
679 iphc0
|= LOWPAN_IPHC_TC_C
;
680 *hc_ptr
= (tmp
& 0xc0) | (hdr
->flow_lbl
[0] & 0x0F);
681 memcpy(hc_ptr
+ 1, &hdr
->flow_lbl
[1], 2);
684 /* compress nothing */
685 memcpy(hc_ptr
, hdr
, 4);
686 /* replace the top byte with new ECN | DSCP format */
692 /* NOTE: payload length is always compressed */
694 /* Next Header is compress if UDP */
695 if (hdr
->nexthdr
== UIP_PROTO_UDP
)
696 iphc0
|= LOWPAN_IPHC_NH_C
;
698 if ((iphc0
& LOWPAN_IPHC_NH_C
) == 0)
699 lowpan_push_hc_data(&hc_ptr
, &hdr
->nexthdr
,
700 sizeof(hdr
->nexthdr
));
704 * if 1: compress, encoding is 01
705 * if 64: compress, encoding is 10
706 * if 255: compress, encoding is 11
707 * else do not compress
709 switch (hdr
->hop_limit
) {
711 iphc0
|= LOWPAN_IPHC_TTL_1
;
714 iphc0
|= LOWPAN_IPHC_TTL_64
;
717 iphc0
|= LOWPAN_IPHC_TTL_255
;
720 lowpan_push_hc_data(&hc_ptr
, &hdr
->hop_limit
,
721 sizeof(hdr
->hop_limit
));
724 addr_type
= ipv6_addr_type(&hdr
->saddr
);
725 /* source address compression */
726 if (addr_type
== IPV6_ADDR_ANY
) {
727 pr_debug("source address is unspecified, setting SAC\n");
728 iphc1
|= LOWPAN_IPHC_SAC
;
730 if (addr_type
& IPV6_ADDR_LINKLOCAL
) {
731 iphc1
|= lowpan_compress_addr_64(&hc_ptr
,
733 &hdr
->saddr
, _saddr
);
734 pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
737 pr_debug("send the full source address\n");
738 lowpan_push_hc_data(&hc_ptr
, hdr
->saddr
.s6_addr
, 16);
742 addr_type
= ipv6_addr_type(&hdr
->daddr
);
743 /* destination address compression */
744 if (addr_type
& IPV6_ADDR_MULTICAST
) {
745 pr_debug("destination address is multicast: ");
746 iphc1
|= LOWPAN_IPHC_M
;
747 if (lowpan_is_mcast_addr_compressable8(&hdr
->daddr
)) {
748 pr_debug("compressed to 1 octet\n");
749 iphc1
|= LOWPAN_IPHC_DAM_11
;
751 lowpan_push_hc_data(&hc_ptr
,
752 &hdr
->daddr
.s6_addr
[15], 1);
753 } else if (lowpan_is_mcast_addr_compressable32(&hdr
->daddr
)) {
754 pr_debug("compressed to 4 octets\n");
755 iphc1
|= LOWPAN_IPHC_DAM_10
;
756 /* second byte + the last three */
757 lowpan_push_hc_data(&hc_ptr
,
758 &hdr
->daddr
.s6_addr
[1], 1);
759 lowpan_push_hc_data(&hc_ptr
,
760 &hdr
->daddr
.s6_addr
[13], 3);
761 } else if (lowpan_is_mcast_addr_compressable48(&hdr
->daddr
)) {
762 pr_debug("compressed to 6 octets\n");
763 iphc1
|= LOWPAN_IPHC_DAM_01
;
764 /* second byte + the last five */
765 lowpan_push_hc_data(&hc_ptr
,
766 &hdr
->daddr
.s6_addr
[1], 1);
767 lowpan_push_hc_data(&hc_ptr
,
768 &hdr
->daddr
.s6_addr
[11], 5);
770 pr_debug("using full address\n");
771 iphc1
|= LOWPAN_IPHC_DAM_00
;
772 lowpan_push_hc_data(&hc_ptr
, hdr
->daddr
.s6_addr
, 16);
775 if (addr_type
& IPV6_ADDR_LINKLOCAL
) {
776 /* TODO: context lookup */
777 iphc1
|= lowpan_compress_addr_64(&hc_ptr
,
778 LOWPAN_IPHC_DAM_BIT
, &hdr
->daddr
, _daddr
);
779 pr_debug("dest address unicast link-local %pI6c "
780 "iphc1 0x%02x\n", &hdr
->daddr
, iphc1
);
782 pr_debug("dest address unicast %pI6c\n", &hdr
->daddr
);
783 lowpan_push_hc_data(&hc_ptr
, hdr
->daddr
.s6_addr
, 16);
787 /* UDP header compression */
788 if (hdr
->nexthdr
== UIP_PROTO_UDP
)
789 compress_udp_header(&hc_ptr
, skb
);
794 skb_pull(skb
, sizeof(struct ipv6hdr
));
795 skb_reset_transport_header(skb
);
796 memcpy(skb_push(skb
, hc_ptr
- head
), head
, hc_ptr
- head
);
797 skb_reset_network_header(skb
);
799 pr_debug("header len %d skb %u\n", (int)(hc_ptr
- head
), skb
->len
);
801 raw_dump_table(__func__
, "raw skb data dump compressed",
802 skb
->data
, skb
->len
);
805 EXPORT_SYMBOL_GPL(lowpan_header_compress
);
807 MODULE_LICENSE("GPL");