1 /**
2 * @file
3 *
4 * 6LowPAN output for IPv6. Uses ND tables for link-layer addressing. Fragments packets to 6LowPAN units.
5 *
6 * This implementation aims to conform to IEEE 802.15.4(-2015), RFC 4944 and RFC 6282.
7 * @todo: RFC 6775.
8 */
9
10 /*
11 * Copyright (c) 2015 Inico Technologies Ltd.
12 * All rights reserved.
13 *
14 * Redistribution and use in source and binary forms, with or without modification,
15 * are permitted provided that the following conditions are met:
16 *
17 * 1. Redistributions of source code must retain the above copyright notice,
18 * this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright notice,
20 * this list of conditions and the following disclaimer in the documentation
21 * and/or other materials provided with the distribution.
22 * 3. The name of the author may not be used to endorse or promote products
23 * derived from this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
26 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
27 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
28 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
29 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
30 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
33 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
34 * OF SUCH DAMAGE.
35 *
36 * This file is part of the lwIP TCP/IP stack.
37 *
38 * Author: Ivan Delamer <delamer@inicotech.com>
39 *
40 *
41 * Please coordinate changes and requests with Ivan Delamer
42 * <delamer@inicotech.com>
43 */
44
45 /**
46 * @defgroup sixlowpan 6LoWPAN (RFC4944)
47 * @ingroup netifs
48 * 6LowPAN netif implementation
49 */
50
51 #include "netif/lowpan6.h"
52
53 #if LWIP_IPV6
54
55 #include "lwip/ip.h"
56 #include "lwip/pbuf.h"
57 #include "lwip/ip_addr.h"
58 #include "lwip/netif.h"
59 #include "lwip/nd6.h"
60 #include "lwip/mem.h"
61 #include "lwip/udp.h"
62 #include "lwip/tcpip.h"
63 #include "lwip/snmp.h"
64 #include "netif/ieee802154.h"
65
66 #if LWIP_LOWPOWER
67 #include "lwip/lowpower.h"
68 #endif
69 #include <string.h>
70
71 #if LWIP_6LOWPAN_802154_HW_CRC
72 #define LWIP_6LOWPAN_DO_CALC_CRC(buf, len) 0
73 #else
74 #define LWIP_6LOWPAN_DO_CALC_CRC(buf, len) LWIP_6LOWPAN_CALC_CRC(buf, len)
75 #endif
76
77 /** This is a helper struct for reassembly of fragments
78 * (IEEE 802.15.4 limits to 127 bytes)
79 */
80 struct lowpan6_reass_helper {
81 struct lowpan6_reass_helper *next_packet;
82 struct pbuf *reass;
83 struct pbuf *frags;
84 u8_t timer;
85 struct lowpan6_link_addr sender_addr;
86 u16_t datagram_size;
87 u16_t datagram_tag;
88 };
89
90 /** This struct keeps track of per-netif state */
91 struct lowpan6_ieee802154_data {
92 /** fragment reassembly list */
93 struct lowpan6_reass_helper *reass_list;
94 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
95 /** address context for compression */
96 ip6_addr_t lowpan6_context[LWIP_6LOWPAN_NUM_CONTEXTS];
97 #endif
98 /** Datagram Tag for fragmentation */
99 u16_t tx_datagram_tag;
100 /** local PAN ID for IEEE 802.15.4 header */
101 u16_t ieee_802154_pan_id;
102 /** Sequence Number for IEEE 802.15.4 transmission */
103 u8_t tx_frame_seq_num;
104 };
105
106 /* Maximum frame size is 127 bytes minus CRC size */
107 #define LOWPAN6_MAX_PAYLOAD (127 - 2)
108
109 /** Currently, this state is global, since there's only one 6LoWPAN netif */
110 static struct lowpan6_ieee802154_data lowpan6_data;
111
112 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
113 #define LWIP_6LOWPAN_CONTEXTS(netif) lowpan6_data.lowpan6_context
114 #else
115 #define LWIP_6LOWPAN_CONTEXTS(netif) NULL
116 #endif
117
118 static const struct lowpan6_link_addr ieee_802154_broadcast = {2, {0xff, 0xff}};
119
120 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
121 static struct lowpan6_link_addr short_mac_addr = {2, {0, 0}};
122 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
123
124 #if LWIP_LOWPOWER
125 u32_t
lowpan6_tmr_tick()126 lowpan6_tmr_tick()
127 {
128 struct lowpan6_reass_helper *lrh = NULL;
129 struct lowpan6_reass_helper *lrh_temp = NULL;
130 u32_t tick = 0;
131
132 lrh = lowpan6_data.reass_list;
133 while (lrh != NULL) {
134 lrh_temp = lrh->next_packet;
135 if (lrh->timer > 0) {
136 SET_TMR_TICK(tick, lrh->timer);
137 }
138 lrh = lrh_temp;
139 }
140
141 LWIP_DEBUGF(LOWPOWER_DEBUG, ("%s tmr tick: %u\n", "lowpan6_tmr_tick", tick));
142 return tick;
143 }
144 #endif /* LWIP_LOWPOWER */
145
146 /* IEEE 802.15.4 specific functions: */
147
148 /** Write the IEEE 802.15.4 header that encapsulates the 6LoWPAN frame.
149 * Src and dst PAN IDs are filled with the ID set by @ref lowpan6_set_pan_id.
150 *
151 * Since the length is variable:
152 * @returns the header length
153 */
154 static u8_t
lowpan6_write_iee802154_header(struct ieee_802154_hdr * hdr,const struct lowpan6_link_addr * src,const struct lowpan6_link_addr * dst)155 lowpan6_write_iee802154_header(struct ieee_802154_hdr *hdr, const struct lowpan6_link_addr *src,
156 const struct lowpan6_link_addr *dst)
157 {
158 u8_t ieee_header_len;
159 u8_t *buffer;
160 u8_t i;
161 u16_t fc;
162
163 fc = IEEE_802154_FC_FT_DATA; /* send data packet (2003 frame version) */
164 fc |= IEEE_802154_FC_PANID_COMPR; /* set PAN ID compression, for now src and dst PANs are equal */
165 if (dst != &ieee_802154_broadcast) {
166 fc |= IEEE_802154_FC_ACK_REQ; /* data packet, no broadcast: ack required. */
167 }
168 if (dst->addr_len == 2) {
169 fc |= IEEE_802154_FC_DST_ADDR_MODE_SHORT;
170 } else {
171 LWIP_ASSERT("invalid dst address length", dst->addr_len == 8);
172 fc |= IEEE_802154_FC_DST_ADDR_MODE_EXT;
173 }
174 if (src->addr_len == 2) {
175 fc |= IEEE_802154_FC_SRC_ADDR_MODE_SHORT;
176 } else {
177 LWIP_ASSERT("invalid src address length", src->addr_len == 8);
178 fc |= IEEE_802154_FC_SRC_ADDR_MODE_EXT;
179 }
180 hdr->frame_control = fc;
181 hdr->sequence_number = lowpan6_data.tx_frame_seq_num++;
182 hdr->destination_pan_id = lowpan6_data.ieee_802154_pan_id; /* pan id */
183
184 buffer = (u8_t *)hdr;
185 ieee_header_len = 5;
186 i = dst->addr_len;
187 /* reverse memcpy of dst addr */
188 while (i-- > 0) {
189 buffer[ieee_header_len++] = dst->addr[i];
190 }
191 /* Source PAN ID skipped due to PAN ID Compression */
192 i = src->addr_len;
193 /* reverse memcpy of src addr */
194 while (i-- > 0) {
195 buffer[ieee_header_len++] = src->addr[i];
196 }
197 return ieee_header_len;
198 }
199
200 /** Parse the IEEE 802.15.4 header from a pbuf.
201 * If successful, the header is hidden from the pbuf.
202 *
203 * PAN IDs and seuqence number are not checked
204 *
205 * @param p input pbuf, p->payload pointing at the IEEE 802.15.4 header
206 * @param src pointer to source address filled from the header
207 * @param dest pointer to destination address filled from the header
208 * @returns ERR_OK if successful
209 */
210 static err_t
lowpan6_parse_iee802154_header(struct pbuf * p,struct lowpan6_link_addr * src,struct lowpan6_link_addr * dest)211 lowpan6_parse_iee802154_header(struct pbuf *p, struct lowpan6_link_addr *src,
212 struct lowpan6_link_addr *dest)
213 {
214 u8_t *puc;
215 s8_t i;
216 u16_t frame_control, addr_mode;
217 u16_t datagram_offset;
218
219 /* Parse IEEE 802.15.4 header */
220 puc = (u8_t *)p->payload;
221 frame_control = puc[0] | (puc[1] << 8);
222 datagram_offset = 2;
223 if (frame_control & IEEE_802154_FC_SEQNO_SUPPR) {
224 if (IEEE_802154_FC_FRAME_VERSION_GET(frame_control) <= 1) {
225 /* sequence number suppressed, this is not valid for versions 0/1 */
226 return ERR_VAL;
227 }
228 } else {
229 datagram_offset++;
230 }
231 datagram_offset += 2; /* Skip destination PAN ID */
232 addr_mode = frame_control & IEEE_802154_FC_DST_ADDR_MODE_MASK;
233 if (addr_mode == IEEE_802154_FC_DST_ADDR_MODE_EXT) {
234 /* extended address (64 bit) */
235 dest->addr_len = 8;
236 /* reverse memcpy: */
237 for (i = 0; i < 8; i++) {
238 dest->addr[i] = puc[datagram_offset + 7 - i];
239 }
240 datagram_offset += 8;
241 } else if (addr_mode == IEEE_802154_FC_DST_ADDR_MODE_SHORT) {
242 /* short address (16 bit) */
243 dest->addr_len = 2;
244 /* reverse memcpy: */
245 dest->addr[0] = puc[datagram_offset + 1];
246 dest->addr[1] = puc[datagram_offset];
247 datagram_offset += 2;
248 } else {
249 /* unsupported address mode (do we need "no address"?) */
250 return ERR_VAL;
251 }
252
253 if (!(frame_control & IEEE_802154_FC_PANID_COMPR)) {
254 /* No PAN ID compression, skip source PAN ID */
255 datagram_offset += 2;
256 }
257
258 addr_mode = frame_control & IEEE_802154_FC_SRC_ADDR_MODE_MASK;
259 if (addr_mode == IEEE_802154_FC_SRC_ADDR_MODE_EXT) {
260 /* extended address (64 bit) */
261 src->addr_len = 8;
262 /* reverse memcpy: */
263 for (i = 0; i < 8; i++) {
264 src->addr[i] = puc[datagram_offset + 7 - i];
265 }
266 datagram_offset += 8;
267 } else if (addr_mode == IEEE_802154_FC_DST_ADDR_MODE_SHORT) {
268 /* short address (16 bit) */
269 src->addr_len = 2;
270 src->addr[0] = puc[datagram_offset + 1];
271 src->addr[1] = puc[datagram_offset];
272 datagram_offset += 2;
273 } else {
274 /* unsupported address mode (do we need "no address"?) */
275 return ERR_VAL;
276 }
277
278 /* hide IEEE802.15.4 header. */
279 if (pbuf_remove_header(p, datagram_offset)) {
280 return ERR_VAL;
281 }
282 return ERR_OK;
283 }
284
285 /** Calculate the 16-bit CRC as required by IEEE 802.15.4 */
286 u16_t
lowpan6_calc_crc(const void * buf,u16_t len)287 lowpan6_calc_crc(const void* buf, u16_t len)
288 {
289 #define CCITT_POLY_16 0x8408U
290 u16_t i;
291 u8_t b;
292 u16_t crc = 0;
293 const u8_t* p = (const u8_t*)buf;
294
295 for (i = 0; i < len; i++) {
296 u8_t data = *p;
297 for (b = 0U; b < 8U; b++) {
298 if (((data ^ crc) & 1) != 0) {
299 crc = (u16_t)((crc >> 1) ^ CCITT_POLY_16);
300 } else {
301 crc = (u16_t)(crc >> 1);
302 }
303 data = (u8_t)(data >> 1);
304 }
305 p++;
306 }
307 return crc;
308 }
309
310 /* Fragmentation specific functions: */
311
312 static void
free_reass_datagram(struct lowpan6_reass_helper * lrh)313 free_reass_datagram(struct lowpan6_reass_helper *lrh)
314 {
315 if (lrh->reass) {
316 pbuf_free(lrh->reass);
317 }
318 if (lrh->frags) {
319 pbuf_free(lrh->frags);
320 }
321 mem_free(lrh);
322 }
323
324 /**
325 * Removes a datagram from the reassembly queue.
326 **/
327 static void
dequeue_datagram(struct lowpan6_reass_helper * lrh,struct lowpan6_reass_helper * prev)328 dequeue_datagram(struct lowpan6_reass_helper *lrh, struct lowpan6_reass_helper *prev)
329 {
330 if (lowpan6_data.reass_list == lrh) {
331 lowpan6_data.reass_list = lowpan6_data.reass_list->next_packet;
332 } else {
333 /* it wasn't the first, so it must have a valid 'prev' */
334 LWIP_ASSERT("sanity check linked list", prev != NULL);
335 prev->next_packet = lrh->next_packet;
336 }
337 }
338
339 /**
340 * Periodic timer for 6LowPAN functions:
341 *
342 * - Remove incomplete/old packets
343 */
344 void
lowpan6_tmr(void)345 lowpan6_tmr(void)
346 {
347 struct lowpan6_reass_helper *lrh, *lrh_next, *lrh_prev = NULL;
348
349 lrh = lowpan6_data.reass_list;
350 while (lrh != NULL) {
351 lrh_next = lrh->next_packet;
352 if ((--lrh->timer) == 0) {
353 dequeue_datagram(lrh, lrh_prev);
354 free_reass_datagram(lrh);
355 } else {
356 lrh_prev = lrh;
357 }
358 lrh = lrh_next;
359 }
360 }
361
362 /*
363 * Encapsulates data into IEEE 802.15.4 frames.
364 * Fragments an IPv6 datagram into 6LowPAN units, which fit into IEEE 802.15.4 frames.
365 * If configured, will compress IPv6 and or UDP headers.
366 * */
367 static err_t
lowpan6_frag(struct netif * netif,struct pbuf * p,const struct lowpan6_link_addr * src,const struct lowpan6_link_addr * dst)368 lowpan6_frag(struct netif *netif, struct pbuf *p, const struct lowpan6_link_addr *src, const struct lowpan6_link_addr *dst)
369 {
370 struct pbuf *p_frag;
371 u16_t frag_len, remaining_len, max_data_len;
372 u8_t *buffer;
373 u8_t ieee_header_len;
374 u8_t lowpan6_header_len;
375 u8_t hidden_header_len;
376 u16_t crc;
377 u16_t datagram_offset;
378 err_t err = ERR_IF;
379
380 LWIP_ASSERT("lowpan6_frag: netif->linkoutput not set", netif->linkoutput != NULL);
381
382 /* We'll use a dedicated pbuf for building 6LowPAN fragments. */
383 p_frag = pbuf_alloc(PBUF_RAW, 127, PBUF_RAM);
384 if (p_frag == NULL) {
385 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
386 return ERR_MEM;
387 }
388 LWIP_ASSERT("this needs a pbuf in one piece", p_frag->len == p_frag->tot_len);
389
390 /* Write IEEE 802.15.4 header. */
391 buffer = (u8_t *)p_frag->payload;
392 ieee_header_len = lowpan6_write_iee802154_header((struct ieee_802154_hdr *)buffer, src, dst);
393 LWIP_ASSERT("ieee_header_len < p_frag->len", ieee_header_len < p_frag->len);
394
395 #if LWIP_6LOWPAN_IPHC
396 /* Perform 6LowPAN IPv6 header compression according to RFC 6282 */
397 /* do the header compression (this does NOT copy any non-compressed data) */
398 err = lowpan6_compress_headers(netif, (u8_t *)p->payload, p->len,
399 &buffer[ieee_header_len], p_frag->len - ieee_header_len, &lowpan6_header_len,
400 &hidden_header_len, LWIP_6LOWPAN_CONTEXTS(netif), src, dst);
401 if (err != ERR_OK) {
402 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
403 pbuf_free(p_frag);
404 return err;
405 }
406 pbuf_remove_header(p, hidden_header_len);
407
408 #else /* LWIP_6LOWPAN_IPHC */
409 /* Send uncompressed IPv6 header with appropriate dispatch byte. */
410 lowpan6_header_len = 1;
411 buffer[ieee_header_len] = 0x41; /* IPv6 dispatch */
412 #endif /* LWIP_6LOWPAN_IPHC */
413
414 /* Calculate remaining packet length */
415 remaining_len = p->tot_len;
416
417 if (remaining_len > 0x7FF) {
418 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
419 /* datagram_size must fit into 11 bit */
420 pbuf_free(p_frag);
421 return ERR_VAL;
422 }
423
424 /* Fragment, or 1 packet? */
425 max_data_len = LOWPAN6_MAX_PAYLOAD - ieee_header_len - lowpan6_header_len;
426 if (remaining_len > max_data_len) {
427 u16_t data_len;
428 /* We must move the 6LowPAN header to make room for the FRAG header. */
429 memmove(&buffer[ieee_header_len + 4], &buffer[ieee_header_len], lowpan6_header_len);
430
431 /* Now we need to fragment the packet. FRAG1 header first */
432 buffer[ieee_header_len] = 0xc0 | (((p->tot_len + hidden_header_len) >> 8) & 0x7);
433 buffer[ieee_header_len + 1] = (p->tot_len + hidden_header_len) & 0xff;
434
435 lowpan6_data.tx_datagram_tag++;
436 buffer[ieee_header_len + 2] = (lowpan6_data.tx_datagram_tag >> 8) & 0xff;
437 buffer[ieee_header_len + 3] = lowpan6_data.tx_datagram_tag & 0xff;
438
439 /* Fragment follows. */
440 data_len = (max_data_len - 4) & 0xf8;
441 frag_len = data_len + lowpan6_header_len;
442
443 pbuf_copy_partial(p, buffer + ieee_header_len + lowpan6_header_len + 4, frag_len - lowpan6_header_len, 0);
444 remaining_len -= frag_len - lowpan6_header_len;
445 /* datagram offset holds the offset before compression */
446 datagram_offset = frag_len - lowpan6_header_len + hidden_header_len;
447 LWIP_ASSERT("datagram offset must be a multiple of 8", (datagram_offset & 7) == 0);
448
449 /* Calculate frame length */
450 p_frag->len = p_frag->tot_len = ieee_header_len + 4 + frag_len + 2; /* add 2 bytes for crc*/
451
452 /* 2 bytes CRC */
453 crc = LWIP_6LOWPAN_DO_CALC_CRC(p_frag->payload, p_frag->len - 2);
454 pbuf_take_at(p_frag, &crc, 2, p_frag->len - 2);
455
456 /* send the packet */
457 MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
458 LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
459 err = netif->linkoutput(netif, p_frag);
460
461 while ((remaining_len > 0) && (err == ERR_OK)) {
462 struct ieee_802154_hdr *hdr = (struct ieee_802154_hdr *)buffer;
463 /* new frame, new seq num for ACK */
464 hdr->sequence_number = lowpan6_data.tx_frame_seq_num++;
465
466 buffer[ieee_header_len] |= 0x20; /* Change FRAG1 to FRAGN */
467
468 LWIP_ASSERT("datagram offset must be a multiple of 8", (datagram_offset & 7) == 0);
469 buffer[ieee_header_len + 4] = (u8_t)(datagram_offset >> 3); /* datagram offset in FRAGN header (datagram_offset is max. 11 bit) */
470
471 frag_len = (127 - ieee_header_len - 5 - 2) & 0xf8;
472 if (frag_len > remaining_len) {
473 frag_len = remaining_len;
474 }
475
476 pbuf_copy_partial(p, buffer + ieee_header_len + 5, frag_len, p->tot_len - remaining_len);
477 remaining_len -= frag_len;
478 datagram_offset += frag_len;
479
480 /* Calculate frame length */
481 p_frag->len = p_frag->tot_len = frag_len + 5 + ieee_header_len + 2;
482
483 /* 2 bytes CRC */
484 crc = LWIP_6LOWPAN_DO_CALC_CRC(p_frag->payload, p_frag->len - 2);
485 pbuf_take_at(p_frag, &crc, 2, p_frag->len - 2);
486
487 /* send the packet */
488 MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
489 LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
490 err = netif->linkoutput(netif, p_frag);
491 }
492 } else {
493 /* It fits in one frame. */
494 frag_len = remaining_len;
495
496 /* Copy IPv6 packet */
497 pbuf_copy_partial(p, buffer + ieee_header_len + lowpan6_header_len, frag_len, 0);
498 remaining_len = 0;
499
500 /* Calculate frame length */
501 p_frag->len = p_frag->tot_len = frag_len + lowpan6_header_len + ieee_header_len + 2;
502 LWIP_ASSERT("", p_frag->len <= 127);
503
504 /* 2 bytes CRC */
505 crc = LWIP_6LOWPAN_DO_CALC_CRC(p_frag->payload, p_frag->len - 2);
506 pbuf_take_at(p_frag, &crc, 2, p_frag->len - 2);
507
508 /* send the packet */
509 MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
510 LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
511 err = netif->linkoutput(netif, p_frag);
512 }
513
514 pbuf_free(p_frag);
515
516 return err;
517 }
518
519 /**
520 * @ingroup sixlowpan
521 * Set context
522 */
523 err_t
lowpan6_set_context(u8_t idx,const ip6_addr_t * context)524 lowpan6_set_context(u8_t idx, const ip6_addr_t *context)
525 {
526 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
527 if (idx >= LWIP_6LOWPAN_NUM_CONTEXTS) {
528 return ERR_ARG;
529 }
530
531 IP6_ADDR_ZONECHECK(context);
532
533 ip6_addr_set(&lowpan6_data.lowpan6_context[idx], context);
534
535 return ERR_OK;
536 #else
537 LWIP_UNUSED_ARG(idx);
538 LWIP_UNUSED_ARG(context);
539 return ERR_ARG;
540 #endif
541 }
542
543 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
544 /**
545 * @ingroup sixlowpan
546 * Set short address
547 */
548 err_t
lowpan6_set_short_addr(u8_t addr_high,u8_t addr_low)549 lowpan6_set_short_addr(u8_t addr_high, u8_t addr_low)
550 {
551 short_mac_addr.addr[0] = addr_high;
552 short_mac_addr.addr[1] = addr_low;
553
554 return ERR_OK;
555 }
556 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
557
558 /* Create IEEE 802.15.4 address from netif address */
559 static err_t
lowpan6_hwaddr_to_addr(struct netif * netif,struct lowpan6_link_addr * addr)560 lowpan6_hwaddr_to_addr(struct netif *netif, struct lowpan6_link_addr *addr)
561 {
562 addr->addr_len = 8;
563 if (netif->hwaddr_len == 8) {
564 LWIP_ERROR("NETIF_MAX_HWADDR_LEN >= 8 required", sizeof(netif->hwaddr) >= 8, return ERR_VAL;);
565 SMEMCPY(addr->addr, netif->hwaddr, 8);
566 } else if (netif->hwaddr_len == 6) {
567 /* Copy from MAC-48 */
568 SMEMCPY(addr->addr, netif->hwaddr, 3);
569 addr->addr[3] = addr->addr[4] = 0xff;
570 SMEMCPY(&addr->addr[5], &netif->hwaddr[3], 3);
571 } else {
572 /* Invalid address length, don't know how to convert this */
573 return ERR_VAL;
574 }
575 return ERR_OK;
576 }
577
578 /**
579 * @ingroup sixlowpan
580 * Resolve and fill-in IEEE 802.15.4 address header for outgoing IPv6 packet.
581 *
582 * Perform Header Compression and fragment if necessary.
583 *
584 * @param netif The lwIP network interface which the IP packet will be sent on.
585 * @param q The pbuf(s) containing the IP packet to be sent.
586 * @param ip6addr The IP address of the packet destination.
587 *
588 * @return err_t
589 */
590 err_t
lowpan6_output(struct netif * netif,struct pbuf * q,const ip6_addr_t * ip6addr)591 lowpan6_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
592 {
593 err_t result;
594 const u8_t *hwaddr;
595 struct lowpan6_link_addr src, dest;
596 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
597 ip6_addr_t ip6_src;
598 struct ip6_hdr *ip6_hdr;
599 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
600
601 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
602 /* Check if we can compress source address (use aligned copy) */
603 ip6_hdr = (struct ip6_hdr *)q->payload;
604 ip6_addr_copy_from_packed(ip6_src, ip6_hdr->src);
605 ip6_addr_assign_zone(&ip6_src, IP6_UNICAST, netif);
606 if (lowpan6_get_address_mode(&ip6_src, &short_mac_addr) == 3) {
607 src.addr_len = 2;
608 src.addr[0] = short_mac_addr.addr[0];
609 src.addr[1] = short_mac_addr.addr[1];
610 } else
611 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
612 {
613 result = lowpan6_hwaddr_to_addr(netif, &src);
614 if (result != ERR_OK) {
615 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
616 return result;
617 }
618 }
619
620 /* multicast destination IP address? */
621 if (ip6_addr_ismulticast(ip6addr)) {
622 MIB2_STATS_NETIF_INC(netif, ifoutnucastpkts);
623 /* We need to send to the broadcast address.*/
624 return lowpan6_frag(netif, q, &src, &ieee_802154_broadcast);
625 }
626
627 /* We have a unicast destination IP address */
628 /* @todo anycast? */
629
630 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
631 if (src.addr_len == 2) {
632 /* If source address was compressable to short_mac_addr, and dest has same subnet and
633 * is also compressable to 2-bytes, assume we can infer dest as a short address too. */
634 dest.addr_len = 2;
635 dest.addr[0] = ((u8_t *)q->payload)[38];
636 dest.addr[1] = ((u8_t *)q->payload)[39];
637 if ((src.addr_len == 2) && (ip6_addr_netcmp_zoneless(&ip6_hdr->src, &ip6_hdr->dest)) &&
638 (lowpan6_get_address_mode(ip6addr, &dest) == 3)) {
639 MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
640 return lowpan6_frag(netif, q, &src, &dest);
641 }
642 }
643 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
644
645 /* Ask ND6 what to do with the packet. */
646 result = nd6_get_next_hop_addr_or_queue(netif, q, ip6addr, &hwaddr);
647 if (result != ERR_OK) {
648 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
649 return result;
650 }
651
652 /* If no hardware address is returned, nd6 has queued the packet for later. */
653 if (hwaddr == NULL) {
654 return ERR_OK;
655 }
656
657 /* Send out the packet using the returned hardware address. */
658 dest.addr_len = netif->hwaddr_len;
659 /* XXX: Inferring the length of the source address from the destination address
660 * is not correct for IEEE 802.15.4, but currently we don't get this information
661 * from the neighbor cache */
662 SMEMCPY(dest.addr, hwaddr, netif->hwaddr_len);
663 MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
664 return lowpan6_frag(netif, q, &src, &dest);
665 }
666 /**
667 * @ingroup sixlowpan
668 * NETIF input function: don't free the input pbuf when returning != ERR_OK!
669 */
670 err_t
lowpan6_input(struct pbuf * p,struct netif * netif)671 lowpan6_input(struct pbuf *p, struct netif *netif)
672 {
673 u8_t *puc, b;
674 s8_t i;
675 struct lowpan6_link_addr src, dest;
676 u16_t datagram_size = 0;
677 u16_t datagram_offset, datagram_tag;
678 struct lowpan6_reass_helper *lrh, *lrh_next, *lrh_prev = NULL;
679
680 if (p == NULL) {
681 return ERR_OK;
682 }
683
684 MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
685
686 if (p->len != p->tot_len) {
687 /* for now, this needs a pbuf in one piece */
688 goto lowpan6_input_discard;
689 }
690
691 if (lowpan6_parse_iee802154_header(p, &src, &dest) != ERR_OK) {
692 goto lowpan6_input_discard;
693 }
694
695 /* Check dispatch. */
696 puc = (u8_t *)p->payload;
697
698 b = *puc;
699 if ((b & 0xf8) == 0xc0) {
700 /* FRAG1 dispatch. add this packet to reassembly list. */
701 datagram_size = ((u16_t)(puc[0] & 0x07) << 8) | (u16_t)puc[1];
702 datagram_tag = ((u16_t)puc[2] << 8) | (u16_t)puc[3];
703
704 /* check for duplicate */
705 lrh = lowpan6_data.reass_list;
706 while (lrh != NULL) {
707 uint8_t discard = 0;
708 lrh_next = lrh->next_packet;
709 if ((lrh->sender_addr.addr_len == src.addr_len) &&
710 (memcmp(lrh->sender_addr.addr, src.addr, src.addr_len) == 0)) {
711 /* address match with packet in reassembly. */
712 if ((datagram_tag == lrh->datagram_tag) && (datagram_size == lrh->datagram_size)) {
713 /* duplicate fragment. */
714 goto lowpan6_input_discard;
715 } else {
716 /* We are receiving the start of a new datagram. Discard old one (incomplete). */
717 discard = 1;
718 }
719 }
720 if (discard) {
721 dequeue_datagram(lrh, lrh_prev);
722 free_reass_datagram(lrh);
723 } else {
724 lrh_prev = lrh;
725 }
726 /* Check next datagram in queue. */
727 lrh = lrh_next;
728 }
729
730 pbuf_remove_header(p, 4); /* hide frag1 dispatch */
731
732 lrh = (struct lowpan6_reass_helper *) mem_malloc(sizeof(struct lowpan6_reass_helper));
733 if (lrh == NULL) {
734 goto lowpan6_input_discard;
735 }
736
737 lrh->sender_addr.addr_len = src.addr_len;
738 for (i = 0; i < src.addr_len; i++) {
739 lrh->sender_addr.addr[i] = src.addr[i];
740 }
741 lrh->datagram_size = datagram_size;
742 lrh->datagram_tag = datagram_tag;
743 lrh->frags = NULL;
744 if (*(u8_t *)p->payload == 0x41) {
745 /* This is a complete IPv6 packet, just skip dispatch byte. */
746 pbuf_remove_header(p, 1); /* hide dispatch byte. */
747 lrh->reass = p;
748 } else if ((*(u8_t *)p->payload & 0xe0 ) == 0x60) {
749 lrh->reass = lowpan6_decompress(p, datagram_size, LWIP_6LOWPAN_CONTEXTS(netif), &src, &dest);
750 if (lrh->reass == NULL) {
751 /* decompression failed */
752 mem_free(lrh);
753 goto lowpan6_input_discard;
754 }
755 }
756 /* TODO: handle the case where we already have FRAGN received */
757 lrh->next_packet = lowpan6_data.reass_list;
758 lrh->timer = 2;
759 lowpan6_data.reass_list = lrh;
760
761 return ERR_OK;
762 } else if ((b & 0xf8) == 0xe0) {
763 /* FRAGN dispatch, find packet being reassembled. */
764 datagram_size = ((u16_t)(puc[0] & 0x07) << 8) | (u16_t)puc[1];
765 datagram_tag = ((u16_t)puc[2] << 8) | (u16_t)puc[3];
766 datagram_offset = (u16_t)puc[4] << 3;
767 pbuf_remove_header(p, 4); /* hide frag1 dispatch but keep datagram offset for reassembly */
768
769 for (lrh = lowpan6_data.reass_list; lrh != NULL; lrh_prev = lrh, lrh = lrh->next_packet) {
770 if ((lrh->sender_addr.addr_len == src.addr_len) &&
771 (memcmp(lrh->sender_addr.addr, src.addr, src.addr_len) == 0) &&
772 (datagram_tag == lrh->datagram_tag) &&
773 (datagram_size == lrh->datagram_size)) {
774 break;
775 }
776 }
777 if (lrh == NULL) {
778 /* rogue fragment */
779 goto lowpan6_input_discard;
780 }
781 /* Insert new pbuf into list of fragments. Each fragment is a pbuf,
782 this only works for unchained pbufs. */
783 LWIP_ASSERT("p->next == NULL", p->next == NULL);
784 if (lrh->reass != NULL) {
785 /* FRAG1 already received, check this offset against first len */
786 if (datagram_offset < lrh->reass->len) {
787 /* fragment overlap, discard old fragments */
788 dequeue_datagram(lrh, lrh_prev);
789 free_reass_datagram(lrh);
790 goto lowpan6_input_discard;
791 }
792 }
793 if (lrh->frags == NULL) {
794 /* first FRAGN */
795 lrh->frags = p;
796 } else {
797 /* find the correct place to insert */
798 struct pbuf *q, *last;
799 u16_t new_frag_len = p->len - 1; /* p->len includes datagram_offset byte */
800 for (q = lrh->frags, last = NULL; q != NULL; last = q, q = q->next) {
801 u16_t q_datagram_offset = ((u8_t *)q->payload)[0] << 3;
802 u16_t q_frag_len = q->len - 1;
803 if (datagram_offset < q_datagram_offset) {
804 if (datagram_offset + new_frag_len > q_datagram_offset) {
805 /* overlap, discard old fragments */
806 dequeue_datagram(lrh, lrh_prev);
807 free_reass_datagram(lrh);
808 goto lowpan6_input_discard;
809 }
810 /* insert here */
811 break;
812 } else if (datagram_offset == q_datagram_offset) {
813 if (q_frag_len != new_frag_len) {
814 /* fragment mismatch, discard old fragments */
815 dequeue_datagram(lrh, lrh_prev);
816 free_reass_datagram(lrh);
817 goto lowpan6_input_discard;
818 }
819 /* duplicate, ignore */
820 pbuf_free(p);
821 return ERR_OK;
822 }
823 }
824 /* insert fragment */
825 if (last == NULL) {
826 lrh->frags = p;
827 } else {
828 last->next = p;
829 p->next = q;
830 }
831 }
832 /* check if all fragments were received */
833 if (lrh->reass) {
834 u16_t offset = lrh->reass->len;
835 struct pbuf *q;
836 for (q = lrh->frags; q != NULL; q = q->next) {
837 u16_t q_datagram_offset = ((u8_t *)q->payload)[0] << 3;
838 if (q_datagram_offset != offset) {
839 /* not complete, wait for more fragments */
840 return ERR_OK;
841 }
842 offset += q->len - 1;
843 }
844 if (offset == datagram_size) {
845 /* all fragments received, combine pbufs */
846 u16_t datagram_left = datagram_size - lrh->reass->len;
847 for (q = lrh->frags; q != NULL; q = q->next) {
848 /* hide datagram_offset byte now */
849 pbuf_remove_header(q, 1);
850 q->tot_len = datagram_left;
851 datagram_left -= q->len;
852 }
853 LWIP_ASSERT("datagram_left == 0", datagram_left == 0);
854 q = lrh->reass;
855 q->tot_len = datagram_size;
856 q->next = lrh->frags;
857 lrh->frags = NULL;
858 lrh->reass = NULL;
859 dequeue_datagram(lrh, lrh_prev);
860 mem_free(lrh);
861
862 /* @todo: distinguish unicast/multicast */
863 MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
864 return ip6_input(q, netif);
865 }
866 }
867 /* pbuf enqueued, waiting for more fragments */
868 return ERR_OK;
869 } else {
870 if (b == 0x41) {
871 /* This is a complete IPv6 packet, just skip dispatch byte. */
872 pbuf_remove_header(p, 1); /* hide dispatch byte. */
873 } else if ((b & 0xe0 ) == 0x60) {
874 /* IPv6 headers are compressed using IPHC. */
875 p = lowpan6_decompress(p, datagram_size, LWIP_6LOWPAN_CONTEXTS(netif), &src, &dest);
876 if (p == NULL) {
877 MIB2_STATS_NETIF_INC(netif, ifindiscards);
878 return ERR_OK;
879 }
880 } else {
881 goto lowpan6_input_discard;
882 }
883
884 /* @todo: distinguish unicast/multicast */
885 MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
886
887 return ip6_input(p, netif);
888 }
889 lowpan6_input_discard:
890 MIB2_STATS_NETIF_INC(netif, ifindiscards);
891 pbuf_free(p);
892 /* always return ERR_OK here to prevent the caller freeing the pbuf */
893 return ERR_OK;
894 }
895
896 /**
897 * @ingroup sixlowpan
898 */
899 err_t
lowpan6_if_init(struct netif * netif)900 lowpan6_if_init(struct netif *netif)
901 {
902 netif->name[0] = 'L';
903 netif->name[1] = '6';
904 netif->output_ip6 = lowpan6_output;
905
906 MIB2_INIT_NETIF(netif, snmp_ifType_other, 0);
907
908 /* maximum transfer unit */
909 netif->mtu = IP6_MIN_MTU_LENGTH;
910
911 /* broadcast capability */
912 netif->flags = NETIF_FLAG_BROADCAST /* | NETIF_FLAG_LOWPAN6 */;
913
914 return ERR_OK;
915 }
916
917 /**
918 * @ingroup sixlowpan
919 * Set PAN ID
920 */
921 err_t
lowpan6_set_pan_id(u16_t pan_id)922 lowpan6_set_pan_id(u16_t pan_id)
923 {
924 lowpan6_data.ieee_802154_pan_id = pan_id;
925
926 return ERR_OK;
927 }
928
929 #if !NO_SYS
930 /**
931 * @ingroup sixlowpan
932 * Pass a received packet to tcpip_thread for input processing
933 *
934 * @param p the received packet, p->payload pointing to the
935 * IEEE 802.15.4 header.
936 * @param inp the network interface on which the packet was received
937 */
938 err_t
tcpip_6lowpan_input(struct pbuf * p,struct netif * inp)939 tcpip_6lowpan_input(struct pbuf *p, struct netif *inp)
940 {
941 return tcpip_inpkt(p, inp, lowpan6_input);
942 }
943 #endif /* !NO_SYS */
944
945 #endif /* LWIP_IPV6 */
946