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 #include <string.h>
67
68 #if LWIP_6LOWPAN_802154_HW_CRC
69 #define LWIP_6LOWPAN_DO_CALC_CRC(buf, len) 0
70 #else
71 #define LWIP_6LOWPAN_DO_CALC_CRC(buf, len) LWIP_6LOWPAN_CALC_CRC(buf, len)
72 #endif
73
74 /** This is a helper struct for reassembly of fragments
75 * (IEEE 802.15.4 limits to 127 bytes)
76 */
77 struct lowpan6_reass_helper {
78 struct lowpan6_reass_helper *next_packet;
79 struct pbuf *reass;
80 struct pbuf *frags;
81 u8_t timer;
82 struct lowpan6_link_addr sender_addr;
83 u16_t datagram_size;
84 u16_t datagram_tag;
85 };
86
87 /** This struct keeps track of per-netif state */
88 struct lowpan6_ieee802154_data {
89 /** fragment reassembly list */
90 struct lowpan6_reass_helper *reass_list;
91 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
92 /** address context for compression */
93 ip6_addr_t lowpan6_context[LWIP_6LOWPAN_NUM_CONTEXTS];
94 #endif
95 /** Datagram Tag for fragmentation */
96 u16_t tx_datagram_tag;
97 /** local PAN ID for IEEE 802.15.4 header */
98 u16_t ieee_802154_pan_id;
99 /** Sequence Number for IEEE 802.15.4 transmission */
100 u8_t tx_frame_seq_num;
101 };
102
103 /* Maximum frame size is 127 bytes minus CRC size */
104 #define LOWPAN6_MAX_PAYLOAD (127 - 2)
105
106 /** Currently, this state is global, since there's only one 6LoWPAN netif */
107 static struct lowpan6_ieee802154_data lowpan6_data;
108
109 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
110 #define LWIP_6LOWPAN_CONTEXTS(netif) lowpan6_data.lowpan6_context
111 #else
112 #define LWIP_6LOWPAN_CONTEXTS(netif) NULL
113 #endif
114
115 static const struct lowpan6_link_addr ieee_802154_broadcast = {2, {0xff, 0xff}};
116
117 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
118 static struct lowpan6_link_addr short_mac_addr = {2, {0, 0}};
119 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
120
121 /* IEEE 802.15.4 specific functions: */
122
123 /** Write the IEEE 802.15.4 header that encapsulates the 6LoWPAN frame.
124 * Src and dst PAN IDs are filled with the ID set by @ref lowpan6_set_pan_id.
125 *
126 * Since the length is variable:
127 * @returns the header length
128 */
129 static u8_t
lowpan6_write_iee802154_header(struct ieee_802154_hdr * hdr,const struct lowpan6_link_addr * src,const struct lowpan6_link_addr * dst)130 lowpan6_write_iee802154_header(struct ieee_802154_hdr *hdr, const struct lowpan6_link_addr *src,
131 const struct lowpan6_link_addr *dst)
132 {
133 u8_t ieee_header_len;
134 u8_t *buffer;
135 u8_t i;
136 u16_t fc;
137
138 fc = IEEE_802154_FC_FT_DATA; /* send data packet (2003 frame version) */
139 fc |= IEEE_802154_FC_PANID_COMPR; /* set PAN ID compression, for now src and dst PANs are equal */
140 if (dst != &ieee_802154_broadcast) {
141 fc |= IEEE_802154_FC_ACK_REQ; /* data packet, no broadcast: ack required. */
142 }
143 if (dst->addr_len == 2) {
144 fc |= IEEE_802154_FC_DST_ADDR_MODE_SHORT;
145 } else {
146 LWIP_ASSERT("invalid dst address length", dst->addr_len == 8);
147 fc |= IEEE_802154_FC_DST_ADDR_MODE_EXT;
148 }
149 if (src->addr_len == 2) {
150 fc |= IEEE_802154_FC_SRC_ADDR_MODE_SHORT;
151 } else {
152 LWIP_ASSERT("invalid src address length", src->addr_len == 8);
153 fc |= IEEE_802154_FC_SRC_ADDR_MODE_EXT;
154 }
155 hdr->frame_control = fc;
156 hdr->sequence_number = lowpan6_data.tx_frame_seq_num++;
157 hdr->destination_pan_id = lowpan6_data.ieee_802154_pan_id; /* pan id */
158
159 buffer = (u8_t *)hdr;
160 ieee_header_len = 5;
161 i = dst->addr_len;
162 /* reverse memcpy of dst addr */
163 while (i-- > 0) {
164 buffer[ieee_header_len++] = dst->addr[i];
165 }
166 /* Source PAN ID skipped due to PAN ID Compression */
167 i = src->addr_len;
168 /* reverse memcpy of src addr */
169 while (i-- > 0) {
170 buffer[ieee_header_len++] = src->addr[i];
171 }
172 return ieee_header_len;
173 }
174
175 /** Parse the IEEE 802.15.4 header from a pbuf.
176 * If successful, the header is hidden from the pbuf.
177 *
178 * PAN IDs and seuqence number are not checked
179 *
180 * @param p input pbuf, p->payload pointing at the IEEE 802.15.4 header
181 * @param src pointer to source address filled from the header
182 * @param dest pointer to destination address filled from the header
183 * @returns ERR_OK if successful
184 */
185 static err_t
lowpan6_parse_iee802154_header(struct pbuf * p,struct lowpan6_link_addr * src,struct lowpan6_link_addr * dest)186 lowpan6_parse_iee802154_header(struct pbuf *p, struct lowpan6_link_addr *src,
187 struct lowpan6_link_addr *dest)
188 {
189 u8_t *puc;
190 s8_t i;
191 u16_t frame_control, addr_mode;
192 u16_t datagram_offset;
193
194 /* Parse IEEE 802.15.4 header */
195 puc = (u8_t *)p->payload;
196 frame_control = puc[0] | (puc[1] << 8);
197 datagram_offset = 2;
198 if (frame_control & IEEE_802154_FC_SEQNO_SUPPR) {
199 if (IEEE_802154_FC_FRAME_VERSION_GET(frame_control) <= 1) {
200 /* sequence number suppressed, this is not valid for versions 0/1 */
201 return ERR_VAL;
202 }
203 } else {
204 datagram_offset++;
205 }
206 datagram_offset += 2; /* Skip destination PAN ID */
207 addr_mode = frame_control & IEEE_802154_FC_DST_ADDR_MODE_MASK;
208 if (addr_mode == IEEE_802154_FC_DST_ADDR_MODE_EXT) {
209 /* extended address (64 bit) */
210 dest->addr_len = 8;
211 /* reverse memcpy: */
212 for (i = 0; i < 8; i++) {
213 dest->addr[i] = puc[datagram_offset + 7 - i];
214 }
215 datagram_offset += 8;
216 } else if (addr_mode == IEEE_802154_FC_DST_ADDR_MODE_SHORT) {
217 /* short address (16 bit) */
218 dest->addr_len = 2;
219 /* reverse memcpy: */
220 dest->addr[0] = puc[datagram_offset + 1];
221 dest->addr[1] = puc[datagram_offset];
222 datagram_offset += 2;
223 } else {
224 /* unsupported address mode (do we need "no address"?) */
225 return ERR_VAL;
226 }
227
228 if (!(frame_control & IEEE_802154_FC_PANID_COMPR)) {
229 /* No PAN ID compression, skip source PAN ID */
230 datagram_offset += 2;
231 }
232
233 addr_mode = frame_control & IEEE_802154_FC_SRC_ADDR_MODE_MASK;
234 if (addr_mode == IEEE_802154_FC_SRC_ADDR_MODE_EXT) {
235 /* extended address (64 bit) */
236 src->addr_len = 8;
237 /* reverse memcpy: */
238 for (i = 0; i < 8; i++) {
239 src->addr[i] = puc[datagram_offset + 7 - i];
240 }
241 datagram_offset += 8;
242 } else if (addr_mode == IEEE_802154_FC_DST_ADDR_MODE_SHORT) {
243 /* short address (16 bit) */
244 src->addr_len = 2;
245 src->addr[0] = puc[datagram_offset + 1];
246 src->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 /* hide IEEE802.15.4 header. */
254 if (pbuf_remove_header(p, datagram_offset)) {
255 return ERR_VAL;
256 }
257 return ERR_OK;
258 }
259
260 /** Calculate the 16-bit CRC as required by IEEE 802.15.4 */
261 u16_t
lowpan6_calc_crc(const void * buf,u16_t len)262 lowpan6_calc_crc(const void* buf, u16_t len)
263 {
264 #define CCITT_POLY_16 0x8408U
265 u16_t i;
266 u8_t b;
267 u16_t crc = 0;
268 const u8_t* p = (const u8_t*)buf;
269
270 for (i = 0; i < len; i++) {
271 u8_t data = *p;
272 for (b = 0U; b < 8U; b++) {
273 if (((data ^ crc) & 1) != 0) {
274 crc = (u16_t)((crc >> 1) ^ CCITT_POLY_16);
275 } else {
276 crc = (u16_t)(crc >> 1);
277 }
278 data = (u8_t)(data >> 1);
279 }
280 p++;
281 }
282 return crc;
283 }
284
285 /* Fragmentation specific functions: */
286
287 static void
free_reass_datagram(struct lowpan6_reass_helper * lrh)288 free_reass_datagram(struct lowpan6_reass_helper *lrh)
289 {
290 if (lrh->reass) {
291 pbuf_free(lrh->reass);
292 }
293 if (lrh->frags) {
294 pbuf_free(lrh->frags);
295 }
296 mem_free(lrh);
297 }
298
299 /**
300 * Removes a datagram from the reassembly queue.
301 **/
302 static void
dequeue_datagram(struct lowpan6_reass_helper * lrh,struct lowpan6_reass_helper * prev)303 dequeue_datagram(struct lowpan6_reass_helper *lrh, struct lowpan6_reass_helper *prev)
304 {
305 if (lowpan6_data.reass_list == lrh) {
306 lowpan6_data.reass_list = lowpan6_data.reass_list->next_packet;
307 } else {
308 /* it wasn't the first, so it must have a valid 'prev' */
309 LWIP_ASSERT("sanity check linked list", prev != NULL);
310 prev->next_packet = lrh->next_packet;
311 }
312 }
313
314 /**
315 * Periodic timer for 6LowPAN functions:
316 *
317 * - Remove incomplete/old packets
318 */
319 void
lowpan6_tmr(void)320 lowpan6_tmr(void)
321 {
322 struct lowpan6_reass_helper *lrh, *lrh_next, *lrh_prev = NULL;
323
324 lrh = lowpan6_data.reass_list;
325 while (lrh != NULL) {
326 lrh_next = lrh->next_packet;
327 if ((--lrh->timer) == 0) {
328 dequeue_datagram(lrh, lrh_prev);
329 free_reass_datagram(lrh);
330 } else {
331 lrh_prev = lrh;
332 }
333 lrh = lrh_next;
334 }
335 }
336
337 /*
338 * Encapsulates data into IEEE 802.15.4 frames.
339 * Fragments an IPv6 datagram into 6LowPAN units, which fit into IEEE 802.15.4 frames.
340 * If configured, will compress IPv6 and or UDP headers.
341 * */
342 static err_t
lowpan6_frag(struct netif * netif,struct pbuf * p,const struct lowpan6_link_addr * src,const struct lowpan6_link_addr * dst)343 lowpan6_frag(struct netif *netif, struct pbuf *p, const struct lowpan6_link_addr *src, const struct lowpan6_link_addr *dst)
344 {
345 struct pbuf *p_frag;
346 u16_t frag_len, remaining_len, max_data_len;
347 u8_t *buffer;
348 u8_t ieee_header_len;
349 u8_t lowpan6_header_len;
350 u8_t hidden_header_len;
351 u16_t crc;
352 u16_t datagram_offset;
353 err_t err = ERR_IF;
354
355 LWIP_ASSERT("lowpan6_frag: netif->linkoutput not set", netif->linkoutput != NULL);
356
357 /* We'll use a dedicated pbuf for building 6LowPAN fragments. */
358 p_frag = pbuf_alloc(PBUF_RAW, 127, PBUF_RAM);
359 if (p_frag == NULL) {
360 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
361 return ERR_MEM;
362 }
363 LWIP_ASSERT("this needs a pbuf in one piece", p_frag->len == p_frag->tot_len);
364
365 /* Write IEEE 802.15.4 header. */
366 buffer = (u8_t *)p_frag->payload;
367 ieee_header_len = lowpan6_write_iee802154_header((struct ieee_802154_hdr *)buffer, src, dst);
368 LWIP_ASSERT("ieee_header_len < p_frag->len", ieee_header_len < p_frag->len);
369
370 #if LWIP_6LOWPAN_IPHC
371 /* Perform 6LowPAN IPv6 header compression according to RFC 6282 */
372 /* do the header compression (this does NOT copy any non-compressed data) */
373 err = lowpan6_compress_headers(netif, (u8_t *)p->payload, p->len,
374 &buffer[ieee_header_len], p_frag->len - ieee_header_len, &lowpan6_header_len,
375 &hidden_header_len, LWIP_6LOWPAN_CONTEXTS(netif), src, dst);
376 if (err != ERR_OK) {
377 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
378 pbuf_free(p_frag);
379 return err;
380 }
381 pbuf_remove_header(p, hidden_header_len);
382
383 #else /* LWIP_6LOWPAN_IPHC */
384 /* Send uncompressed IPv6 header with appropriate dispatch byte. */
385 lowpan6_header_len = 1;
386 hidden_header_len = 0;
387 buffer[ieee_header_len] = 0x41; /* IPv6 dispatch */
388 #endif /* LWIP_6LOWPAN_IPHC */
389
390 /* Calculate remaining packet length */
391 remaining_len = p->tot_len;
392
393 if (remaining_len > 0x7FF) {
394 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
395 /* datagram_size must fit into 11 bit */
396 pbuf_free(p_frag);
397 return ERR_VAL;
398 }
399
400 /* Fragment, or 1 packet? */
401 max_data_len = LOWPAN6_MAX_PAYLOAD - ieee_header_len - lowpan6_header_len;
402 if (remaining_len > max_data_len) {
403 u16_t data_len;
404 /* We must move the 6LowPAN header to make room for the FRAG header. */
405 memmove(&buffer[ieee_header_len + 4], &buffer[ieee_header_len], lowpan6_header_len);
406
407 /* Now we need to fragment the packet. FRAG1 header first */
408 buffer[ieee_header_len] = 0xc0 | (((p->tot_len + hidden_header_len) >> 8) & 0x7);
409 buffer[ieee_header_len + 1] = (p->tot_len + hidden_header_len) & 0xff;
410
411 lowpan6_data.tx_datagram_tag++;
412 buffer[ieee_header_len + 2] = (lowpan6_data.tx_datagram_tag >> 8) & 0xff;
413 buffer[ieee_header_len + 3] = lowpan6_data.tx_datagram_tag & 0xff;
414
415 /* Fragment follows. */
416 data_len = (max_data_len - 4) & 0xf8;
417 frag_len = data_len + lowpan6_header_len;
418
419 pbuf_copy_partial(p, buffer + ieee_header_len + lowpan6_header_len + 4, frag_len - lowpan6_header_len, 0);
420 remaining_len -= frag_len - lowpan6_header_len;
421 /* datagram offset holds the offset before compression */
422 datagram_offset = frag_len - lowpan6_header_len + hidden_header_len;
423 LWIP_ASSERT("datagram offset must be a multiple of 8", (datagram_offset & 7) == 0);
424
425 /* Calculate frame length */
426 p_frag->len = p_frag->tot_len = ieee_header_len + 4 + frag_len + 2; /* add 2 bytes for crc*/
427
428 /* 2 bytes CRC */
429 crc = LWIP_6LOWPAN_DO_CALC_CRC(p_frag->payload, p_frag->len - 2);
430 pbuf_take_at(p_frag, &crc, 2, p_frag->len - 2);
431
432 /* send the packet */
433 MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
434 LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
435 err = netif->linkoutput(netif, p_frag);
436
437 while ((remaining_len > 0) && (err == ERR_OK)) {
438 struct ieee_802154_hdr *hdr = (struct ieee_802154_hdr *)buffer;
439 /* new frame, new seq num for ACK */
440 hdr->sequence_number = lowpan6_data.tx_frame_seq_num++;
441
442 buffer[ieee_header_len] |= 0x20; /* Change FRAG1 to FRAGN */
443
444 LWIP_ASSERT("datagram offset must be a multiple of 8", (datagram_offset & 7) == 0);
445 buffer[ieee_header_len + 4] = (u8_t)(datagram_offset >> 3); /* datagram offset in FRAGN header (datagram_offset is max. 11 bit) */
446
447 frag_len = (127 - ieee_header_len - 5 - 2) & 0xf8;
448 if (frag_len > remaining_len) {
449 frag_len = remaining_len;
450 }
451
452 pbuf_copy_partial(p, buffer + ieee_header_len + 5, frag_len, p->tot_len - remaining_len);
453 remaining_len -= frag_len;
454 datagram_offset += frag_len;
455
456 /* Calculate frame length */
457 p_frag->len = p_frag->tot_len = frag_len + 5 + ieee_header_len + 2;
458
459 /* 2 bytes CRC */
460 crc = LWIP_6LOWPAN_DO_CALC_CRC(p_frag->payload, p_frag->len - 2);
461 pbuf_take_at(p_frag, &crc, 2, p_frag->len - 2);
462
463 /* send the packet */
464 MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
465 LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
466 err = netif->linkoutput(netif, p_frag);
467 }
468 } else {
469 /* It fits in one frame. */
470 frag_len = remaining_len;
471
472 /* Copy IPv6 packet */
473 pbuf_copy_partial(p, buffer + ieee_header_len + lowpan6_header_len, frag_len, 0);
474 remaining_len = 0;
475
476 /* Calculate frame length */
477 p_frag->len = p_frag->tot_len = frag_len + lowpan6_header_len + ieee_header_len + 2;
478 LWIP_ASSERT("", p_frag->len <= 127);
479
480 /* 2 bytes CRC */
481 crc = LWIP_6LOWPAN_DO_CALC_CRC(p_frag->payload, p_frag->len - 2);
482 pbuf_take_at(p_frag, &crc, 2, p_frag->len - 2);
483
484 /* send the packet */
485 MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
486 LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
487 err = netif->linkoutput(netif, p_frag);
488 }
489
490 pbuf_free(p_frag);
491
492 return err;
493 }
494
495 /**
496 * @ingroup sixlowpan
497 * Set context
498 */
499 err_t
lowpan6_set_context(u8_t idx,const ip6_addr_t * context)500 lowpan6_set_context(u8_t idx, const ip6_addr_t *context)
501 {
502 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
503 if (idx >= LWIP_6LOWPAN_NUM_CONTEXTS) {
504 return ERR_ARG;
505 }
506
507 IP6_ADDR_ZONECHECK(context);
508
509 ip6_addr_set(&lowpan6_data.lowpan6_context[idx], context);
510
511 return ERR_OK;
512 #else
513 LWIP_UNUSED_ARG(idx);
514 LWIP_UNUSED_ARG(context);
515 return ERR_ARG;
516 #endif
517 }
518
519 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
520 /**
521 * @ingroup sixlowpan
522 * Set short address
523 */
524 err_t
lowpan6_set_short_addr(u8_t addr_high,u8_t addr_low)525 lowpan6_set_short_addr(u8_t addr_high, u8_t addr_low)
526 {
527 short_mac_addr.addr[0] = addr_high;
528 short_mac_addr.addr[1] = addr_low;
529
530 return ERR_OK;
531 }
532 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
533
534 /* Create IEEE 802.15.4 address from netif address */
535 static err_t
lowpan6_hwaddr_to_addr(struct netif * netif,struct lowpan6_link_addr * addr)536 lowpan6_hwaddr_to_addr(struct netif *netif, struct lowpan6_link_addr *addr)
537 {
538 addr->addr_len = 8;
539 if (netif->hwaddr_len == 8) {
540 LWIP_ERROR("NETIF_MAX_HWADDR_LEN >= 8 required", sizeof(netif->hwaddr) >= 8, return ERR_VAL;);
541 SMEMCPY(addr->addr, netif->hwaddr, 8);
542 } else if (netif->hwaddr_len == 6) {
543 /* Copy from MAC-48 */
544 SMEMCPY(addr->addr, netif->hwaddr, 3);
545 addr->addr[3] = addr->addr[4] = 0xff;
546 SMEMCPY(&addr->addr[5], &netif->hwaddr[3], 3);
547 } else {
548 /* Invalid address length, don't know how to convert this */
549 return ERR_VAL;
550 }
551 return ERR_OK;
552 }
553
554 /**
555 * @ingroup sixlowpan
556 * Resolve and fill-in IEEE 802.15.4 address header for outgoing IPv6 packet.
557 *
558 * Perform Header Compression and fragment if necessary.
559 *
560 * @param netif The lwIP network interface which the IP packet will be sent on.
561 * @param q The pbuf(s) containing the IP packet to be sent.
562 * @param ip6addr The IP address of the packet destination.
563 *
564 * @return err_t
565 */
566 err_t
lowpan6_output(struct netif * netif,struct pbuf * q,const ip6_addr_t * ip6addr)567 lowpan6_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
568 {
569 err_t result;
570 const u8_t *hwaddr;
571 struct lowpan6_link_addr src, dest;
572 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
573 ip6_addr_t ip6_src;
574 struct ip6_hdr *ip6_hdr;
575 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
576
577 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
578 /* Check if we can compress source address (use aligned copy) */
579 ip6_hdr = (struct ip6_hdr *)q->payload;
580 ip6_addr_copy_from_packed(ip6_src, ip6_hdr->src);
581 ip6_addr_assign_zone(&ip6_src, IP6_UNICAST, netif);
582 if (lowpan6_get_address_mode(&ip6_src, &short_mac_addr) == 3) {
583 src.addr_len = 2;
584 src.addr[0] = short_mac_addr.addr[0];
585 src.addr[1] = short_mac_addr.addr[1];
586 } else
587 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
588 {
589 result = lowpan6_hwaddr_to_addr(netif, &src);
590 if (result != ERR_OK) {
591 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
592 return result;
593 }
594 }
595
596 /* multicast destination IP address? */
597 if (ip6_addr_ismulticast(ip6addr)) {
598 MIB2_STATS_NETIF_INC(netif, ifoutnucastpkts);
599 /* We need to send to the broadcast address.*/
600 return lowpan6_frag(netif, q, &src, &ieee_802154_broadcast);
601 }
602
603 /* We have a unicast destination IP address */
604 /* @todo anycast? */
605
606 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
607 if (src.addr_len == 2) {
608 /* If source address was compressible to short_mac_addr, and dest has same subnet and
609 * is also compressible to 2-bytes, assume we can infer dest as a short address too. */
610 dest.addr_len = 2;
611 dest.addr[0] = ((u8_t *)q->payload)[38];
612 dest.addr[1] = ((u8_t *)q->payload)[39];
613 if ((src.addr_len == 2) && (ip6_addr_net_zoneless_eq(&ip6_hdr->src, &ip6_hdr->dest)) &&
614 (lowpan6_get_address_mode(ip6addr, &dest) == 3)) {
615 MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
616 return lowpan6_frag(netif, q, &src, &dest);
617 }
618 }
619 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
620
621 /* Ask ND6 what to do with the packet. */
622 result = nd6_get_next_hop_addr_or_queue(netif, q, ip6addr, &hwaddr);
623 if (result != ERR_OK) {
624 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
625 return result;
626 }
627
628 /* If no hardware address is returned, nd6 has queued the packet for later. */
629 if (hwaddr == NULL) {
630 return ERR_OK;
631 }
632
633 /* Send out the packet using the returned hardware address. */
634 dest.addr_len = netif->hwaddr_len;
635 /* XXX: Inferring the length of the source address from the destination address
636 * is not correct for IEEE 802.15.4, but currently we don't get this information
637 * from the neighbor cache */
638 SMEMCPY(dest.addr, hwaddr, netif->hwaddr_len);
639 MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
640 return lowpan6_frag(netif, q, &src, &dest);
641 }
642 /**
643 * @ingroup sixlowpan
644 * NETIF input function: don't free the input pbuf when returning != ERR_OK!
645 */
646 err_t
lowpan6_input(struct pbuf * p,struct netif * netif)647 lowpan6_input(struct pbuf *p, struct netif *netif)
648 {
649 u8_t *puc, b;
650 s8_t i;
651 struct lowpan6_link_addr src, dest;
652 u16_t datagram_size = 0;
653 u16_t datagram_offset, datagram_tag;
654 struct lowpan6_reass_helper *lrh, *lrh_next, *lrh_prev = NULL;
655
656 if (p == NULL) {
657 return ERR_OK;
658 }
659
660 MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
661
662 if (p->len != p->tot_len) {
663 /* for now, this needs a pbuf in one piece */
664 goto lowpan6_input_discard;
665 }
666
667 if (lowpan6_parse_iee802154_header(p, &src, &dest) != ERR_OK) {
668 goto lowpan6_input_discard;
669 }
670
671 /* Check dispatch. */
672 puc = (u8_t *)p->payload;
673
674 b = *puc;
675 if ((b & 0xf8) == 0xc0) {
676 /* FRAG1 dispatch. add this packet to reassembly list. */
677 datagram_size = ((u16_t)(puc[0] & 0x07) << 8) | (u16_t)puc[1];
678 datagram_tag = ((u16_t)puc[2] << 8) | (u16_t)puc[3];
679
680 /* check for duplicate */
681 lrh = lowpan6_data.reass_list;
682 while (lrh != NULL) {
683 u8_t discard = 0;
684 lrh_next = lrh->next_packet;
685 if ((lrh->sender_addr.addr_len == src.addr_len) &&
686 (memcmp(lrh->sender_addr.addr, src.addr, src.addr_len) == 0)) {
687 /* address match with packet in reassembly. */
688 if ((datagram_tag == lrh->datagram_tag) && (datagram_size == lrh->datagram_size)) {
689 /* duplicate fragment. */
690 goto lowpan6_input_discard;
691 } else {
692 /* We are receiving the start of a new datagram. Discard old one (incomplete). */
693 discard = 1;
694 }
695 }
696 if (discard) {
697 dequeue_datagram(lrh, lrh_prev);
698 free_reass_datagram(lrh);
699 } else {
700 lrh_prev = lrh;
701 }
702 /* Check next datagram in queue. */
703 lrh = lrh_next;
704 }
705
706 pbuf_remove_header(p, 4); /* hide frag1 dispatch */
707
708 lrh = (struct lowpan6_reass_helper *) mem_malloc(sizeof(struct lowpan6_reass_helper));
709 if (lrh == NULL) {
710 goto lowpan6_input_discard;
711 }
712
713 lrh->sender_addr.addr_len = src.addr_len;
714 for (i = 0; i < src.addr_len; i++) {
715 lrh->sender_addr.addr[i] = src.addr[i];
716 }
717 lrh->datagram_size = datagram_size;
718 lrh->datagram_tag = datagram_tag;
719 lrh->frags = NULL;
720 if (*(u8_t *)p->payload == 0x41) {
721 /* This is a complete IPv6 packet, just skip dispatch byte. */
722 pbuf_remove_header(p, 1); /* hide dispatch byte. */
723 lrh->reass = p;
724 } else if ((*(u8_t *)p->payload & 0xe0 ) == 0x60) {
725 lrh->reass = lowpan6_decompress(p, datagram_size, LWIP_6LOWPAN_CONTEXTS(netif), &src, &dest);
726 if (lrh->reass == NULL) {
727 /* decompression failed */
728 mem_free(lrh);
729 goto lowpan6_input_discard;
730 }
731 }
732 /* TODO: handle the case where we already have FRAGN received */
733 lrh->next_packet = lowpan6_data.reass_list;
734 lrh->timer = 2;
735 lowpan6_data.reass_list = lrh;
736
737 return ERR_OK;
738 } else if ((b & 0xf8) == 0xe0) {
739 /* FRAGN dispatch, find packet being reassembled. */
740 datagram_size = ((u16_t)(puc[0] & 0x07) << 8) | (u16_t)puc[1];
741 datagram_tag = ((u16_t)puc[2] << 8) | (u16_t)puc[3];
742 datagram_offset = (u16_t)puc[4] << 3;
743 pbuf_remove_header(p, 4); /* hide frag1 dispatch but keep datagram offset for reassembly */
744
745 for (lrh = lowpan6_data.reass_list; lrh != NULL; lrh_prev = lrh, lrh = lrh->next_packet) {
746 if ((lrh->sender_addr.addr_len == src.addr_len) &&
747 (memcmp(lrh->sender_addr.addr, src.addr, src.addr_len) == 0) &&
748 (datagram_tag == lrh->datagram_tag) &&
749 (datagram_size == lrh->datagram_size)) {
750 break;
751 }
752 }
753 if (lrh == NULL) {
754 /* rogue fragment */
755 goto lowpan6_input_discard;
756 }
757 /* Insert new pbuf into list of fragments. Each fragment is a pbuf,
758 this only works for unchained pbufs. */
759 LWIP_ASSERT("p->next == NULL", p->next == NULL);
760 if (lrh->reass != NULL) {
761 /* FRAG1 already received, check this offset against first len */
762 if (datagram_offset < lrh->reass->len) {
763 /* fragment overlap, discard old fragments */
764 dequeue_datagram(lrh, lrh_prev);
765 free_reass_datagram(lrh);
766 goto lowpan6_input_discard;
767 }
768 }
769 if (lrh->frags == NULL) {
770 /* first FRAGN */
771 lrh->frags = p;
772 } else {
773 /* find the correct place to insert */
774 struct pbuf *q, *last;
775 u16_t new_frag_len = p->len - 1; /* p->len includes datagram_offset byte */
776 for (q = lrh->frags, last = NULL; q != NULL; last = q, q = q->next) {
777 u16_t q_datagram_offset = ((u8_t *)q->payload)[0] << 3;
778 u16_t q_frag_len = q->len - 1;
779 if (datagram_offset < q_datagram_offset) {
780 if (datagram_offset + new_frag_len > q_datagram_offset) {
781 /* overlap, discard old fragments */
782 dequeue_datagram(lrh, lrh_prev);
783 free_reass_datagram(lrh);
784 goto lowpan6_input_discard;
785 }
786 /* insert here */
787 break;
788 } else if (datagram_offset == q_datagram_offset) {
789 if (q_frag_len != new_frag_len) {
790 /* fragment mismatch, discard old fragments */
791 dequeue_datagram(lrh, lrh_prev);
792 free_reass_datagram(lrh);
793 goto lowpan6_input_discard;
794 }
795 /* duplicate, ignore */
796 pbuf_free(p);
797 return ERR_OK;
798 }
799 }
800 /* insert fragment */
801 if (last == NULL) {
802 lrh->frags = p;
803 } else {
804 last->next = p;
805 p->next = q;
806 }
807 }
808 /* check if all fragments were received */
809 if (lrh->reass) {
810 u16_t offset = lrh->reass->len;
811 struct pbuf *q;
812 for (q = lrh->frags; q != NULL; q = q->next) {
813 u16_t q_datagram_offset = ((u8_t *)q->payload)[0] << 3;
814 if (q_datagram_offset != offset) {
815 /* not complete, wait for more fragments */
816 return ERR_OK;
817 }
818 offset += q->len - 1;
819 }
820 if (offset == datagram_size) {
821 /* all fragments received, combine pbufs */
822 u16_t datagram_left = datagram_size - lrh->reass->len;
823 for (q = lrh->frags; q != NULL; q = q->next) {
824 /* hide datagram_offset byte now */
825 pbuf_remove_header(q, 1);
826 q->tot_len = datagram_left;
827 datagram_left -= q->len;
828 }
829 LWIP_ASSERT("datagram_left == 0", datagram_left == 0);
830 q = lrh->reass;
831 q->tot_len = datagram_size;
832 q->next = lrh->frags;
833 lrh->frags = NULL;
834 lrh->reass = NULL;
835 dequeue_datagram(lrh, lrh_prev);
836 mem_free(lrh);
837
838 /* @todo: distinguish unicast/multicast */
839 MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
840 return ip6_input(q, netif);
841 }
842 }
843 /* pbuf enqueued, waiting for more fragments */
844 return ERR_OK;
845 } else {
846 if (b == 0x41) {
847 /* This is a complete IPv6 packet, just skip dispatch byte. */
848 pbuf_remove_header(p, 1); /* hide dispatch byte. */
849 } else if ((b & 0xe0 ) == 0x60) {
850 /* IPv6 headers are compressed using IPHC. */
851 p = lowpan6_decompress(p, datagram_size, LWIP_6LOWPAN_CONTEXTS(netif), &src, &dest);
852 if (p == NULL) {
853 MIB2_STATS_NETIF_INC(netif, ifindiscards);
854 return ERR_OK;
855 }
856 } else {
857 goto lowpan6_input_discard;
858 }
859
860 /* @todo: distinguish unicast/multicast */
861 MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
862
863 return ip6_input(p, netif);
864 }
865 lowpan6_input_discard:
866 MIB2_STATS_NETIF_INC(netif, ifindiscards);
867 pbuf_free(p);
868 /* always return ERR_OK here to prevent the caller freeing the pbuf */
869 return ERR_OK;
870 }
871
872 /**
873 * @ingroup sixlowpan
874 */
875 err_t
lowpan6_if_init(struct netif * netif)876 lowpan6_if_init(struct netif *netif)
877 {
878 netif->name[0] = 'L';
879 netif->name[1] = '6';
880 netif->output_ip6 = lowpan6_output;
881
882 MIB2_INIT_NETIF(netif, snmp_ifType_other, 0);
883
884 /* maximum transfer unit */
885 netif->mtu = IP6_MIN_MTU_LENGTH;
886
887 /* broadcast capability */
888 netif->flags = NETIF_FLAG_BROADCAST /* | NETIF_FLAG_LOWPAN6 */;
889
890 return ERR_OK;
891 }
892
893 /**
894 * @ingroup sixlowpan
895 * Set PAN ID
896 */
897 err_t
lowpan6_set_pan_id(u16_t pan_id)898 lowpan6_set_pan_id(u16_t pan_id)
899 {
900 lowpan6_data.ieee_802154_pan_id = pan_id;
901
902 return ERR_OK;
903 }
904
905 #if !NO_SYS
906 /**
907 * @ingroup sixlowpan
908 * Pass a received packet to tcpip_thread for input processing
909 *
910 * @param p the received packet, p->payload pointing to the
911 * IEEE 802.15.4 header.
912 * @param inp the network interface on which the packet was received
913 */
914 err_t
tcpip_6lowpan_input(struct pbuf * p,struct netif * inp)915 tcpip_6lowpan_input(struct pbuf *p, struct netif *inp)
916 {
917 return tcpip_inpkt(p, inp, lowpan6_input);
918 }
919 #endif /* !NO_SYS */
920
921 #endif /* LWIP_IPV6 */
922