1 /**
2 * @file
3 * 6LowPAN over BLE output for IPv6 (RFC7668).
4 */
5
6 /*
7 * Copyright (c) 2017 Benjamin Aigner
8 * Copyright (c) 2015 Inico Technologies Ltd. , Author: Ivan Delamer <delamer@inicotech.com>
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without modification,
13 * are permitted provided that the following conditions are met:
14 *
15 * 1. Redistributions of source code must retain the above copyright notice,
16 * this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright notice,
18 * this list of conditions and the following disclaimer in the documentation
19 * and/or other materials provided with the distribution.
20 * 3. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
24 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
26 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
27 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
28 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
31 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
32 * OF SUCH DAMAGE.
33 *
34 * Author: Benjamin Aigner <aignerb@technikum-wien.at>
35 *
36 * Based on the original 6lowpan implementation of lwIP ( @see 6lowpan.c)
37 */
38
39
40 /**
41 * @defgroup rfc7668if 6LoWPAN over BLE (RFC7668)
42 * @ingroup netifs
43 * This file implements a RFC7668 implementation for 6LoWPAN over
44 * Bluetooth Low Energy. The specification is very similar to 6LoWPAN,
45 * so most of the code is re-used.
46 * Compared to 6LoWPAN, much functionality is already implemented in
47 * lower BLE layers (fragmenting, session management,...).
48 *
49 * Usage:
50 * - add this netif
51 * - don't add IPv4 addresses (no IPv4 support in RFC7668), pass 'NULL','NULL','NULL'
52 * - use the BLE to EUI64 conversation util to create an IPv6 link-local address from the BLE MAC (@ref ble_addr_to_eui64)
53 * - input function: @ref rfc7668_input
54 * - set the link output function, which transmits output data to an established L2CAP channel
55 * - If data arrives (HCI event "L2CAP_DATA_PACKET"):
56 * - allocate a @ref PBUF_RAW buffer
57 * - let the pbuf struct point to the incoming data or copy it to the buffer
58 * - call netif->input
59 *
60 * @todo:
61 * - further testing
62 * - support compression contexts
63 * - support multiple addresses
64 * - support multicast
65 * - support neighbor discovery
66 */
67
68
69 #include "netif/lowpan6_ble.h"
70
71 #if LWIP_IPV6
72
73 #include "lwip/ip.h"
74 #include "lwip/pbuf.h"
75 #include "lwip/ip_addr.h"
76 #include "lwip/netif.h"
77 #include "lwip/nd6.h"
78 #include "lwip/mem.h"
79 #include "lwip/udp.h"
80 #include "lwip/tcpip.h"
81 #include "lwip/snmp.h"
82
83 #include <string.h>
84
85 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
86 /** context memory, containing IPv6 addresses */
87 static ip6_addr_t rfc7668_context[LWIP_6LOWPAN_NUM_CONTEXTS];
88 #else
89 #define rfc7668_context NULL
90 #endif
91
92 static struct lowpan6_link_addr rfc7668_local_addr;
93 static struct lowpan6_link_addr rfc7668_peer_addr;
94
95 /**
96 * @ingroup rfc7668if
97 * convert BT address to EUI64 addr
98 *
99 * This method converts a Bluetooth MAC address to an EUI64 address,
100 * which is used within IPv6 communication
101 *
102 * @param dst IPv6 destination space
103 * @param src BLE MAC address source
104 * @param public_addr If the LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS
105 * option is set, bit 0x02 will be set if param=0 (no public addr); cleared otherwise
106 *
107 * @see LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS
108 */
109 void
ble_addr_to_eui64(uint8_t * dst,const uint8_t * src,int public_addr)110 ble_addr_to_eui64(uint8_t *dst, const uint8_t *src, int public_addr)
111 {
112 /* according to RFC7668 ch 3.2.2. */
113 memcpy(dst, src, 3);
114 dst[3] = 0xFF;
115 dst[4] = 0xFE;
116 memcpy(&dst[5], &src[3], 3);
117 #if LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS
118 if(public_addr) {
119 dst[0] &= ~0x02;
120 } else {
121 dst[0] |= 0x02;
122 }
123 #else
124 LWIP_UNUSED_ARG(public_addr);
125 #endif
126 }
127
128 /**
129 * @ingroup rfc7668if
130 * convert EUI64 address to Bluetooth MAC addr
131 *
132 * This method converts an EUI64 address to a Bluetooth MAC address,
133 *
134 * @param dst BLE MAC address destination
135 * @param src IPv6 source
136 *
137 */
138 void
eui64_to_ble_addr(uint8_t * dst,const uint8_t * src)139 eui64_to_ble_addr(uint8_t *dst, const uint8_t *src)
140 {
141 /* according to RFC7668 ch 3.2.2. */
142 memcpy(dst,src,3);
143 memcpy(&dst[3],&src[5],3);
144 }
145
146 /** Set an address used for stateful compression.
147 * This expects an address of 6 or 8 bytes.
148 */
149 static err_t
rfc7668_set_addr(struct lowpan6_link_addr * addr,const u8_t * in_addr,size_t in_addr_len,int is_mac_48,int is_public_addr)150 rfc7668_set_addr(struct lowpan6_link_addr *addr, const u8_t *in_addr, size_t in_addr_len, int is_mac_48, int is_public_addr)
151 {
152 if ((in_addr == NULL) || (addr == NULL)) {
153 return ERR_VAL;
154 }
155 if (is_mac_48) {
156 if (in_addr_len != 6) {
157 return ERR_VAL;
158 }
159 addr->addr_len = 8;
160 ble_addr_to_eui64(addr->addr, in_addr, is_public_addr);
161 } else {
162 if (in_addr_len != 8) {
163 return ERR_VAL;
164 }
165 addr->addr_len = 8;
166 memcpy(addr->addr, in_addr, 8);
167 }
168 return ERR_OK;
169 }
170
171
172 /** Set the local address used for stateful compression.
173 * This expects an address of 8 bytes.
174 */
175 err_t
rfc7668_set_local_addr_eui64(struct netif * netif,const u8_t * local_addr,size_t local_addr_len)176 rfc7668_set_local_addr_eui64(struct netif *netif, const u8_t *local_addr, size_t local_addr_len)
177 {
178 /* netif not used for now, the address is stored globally... */
179 LWIP_UNUSED_ARG(netif);
180 return rfc7668_set_addr(&rfc7668_local_addr, local_addr, local_addr_len, 0, 0);
181 }
182
183 /** Set the local address used for stateful compression.
184 * This expects an address of 6 bytes.
185 */
186 err_t
rfc7668_set_local_addr_mac48(struct netif * netif,const u8_t * local_addr,size_t local_addr_len,int is_public_addr)187 rfc7668_set_local_addr_mac48(struct netif *netif, const u8_t *local_addr, size_t local_addr_len, int is_public_addr)
188 {
189 /* netif not used for now, the address is stored globally... */
190 LWIP_UNUSED_ARG(netif);
191 return rfc7668_set_addr(&rfc7668_local_addr, local_addr, local_addr_len, 1, is_public_addr);
192 }
193
194 /** Set the peer address used for stateful compression.
195 * This expects an address of 8 bytes.
196 */
197 err_t
rfc7668_set_peer_addr_eui64(struct netif * netif,const u8_t * peer_addr,size_t peer_addr_len)198 rfc7668_set_peer_addr_eui64(struct netif *netif, const u8_t *peer_addr, size_t peer_addr_len)
199 {
200 /* netif not used for now, the address is stored globally... */
201 LWIP_UNUSED_ARG(netif);
202 return rfc7668_set_addr(&rfc7668_peer_addr, peer_addr, peer_addr_len, 0, 0);
203 }
204
205 /** Set the peer address used for stateful compression.
206 * This expects an address of 6 bytes.
207 */
208 err_t
rfc7668_set_peer_addr_mac48(struct netif * netif,const u8_t * peer_addr,size_t peer_addr_len,int is_public_addr)209 rfc7668_set_peer_addr_mac48(struct netif *netif, const u8_t *peer_addr, size_t peer_addr_len, int is_public_addr)
210 {
211 /* netif not used for now, the address is stored globally... */
212 LWIP_UNUSED_ARG(netif);
213 return rfc7668_set_addr(&rfc7668_peer_addr, peer_addr, peer_addr_len, 1, is_public_addr);
214 }
215
216 /** Encapsulate IPv6 frames for BLE transmission
217 *
218 * This method implements the IPv6 header compression:
219 * *) According to RFC6282
220 * *) See Figure 2, contains base format of bit positions
221 * *) Fragmentation not necessary (done at L2CAP layer of BLE)
222 * @note Currently the pbuf allocation uses 256 bytes. If longer packets are used (possible due to MTU=1480Bytes), increase it here!
223 *
224 * @param p Pbuf struct, containing the payload data
225 * @param netif Output network interface. Should be of RFC7668 type
226 *
227 * @return Same as netif->output.
228 */
229 static err_t
rfc7668_compress(struct netif * netif,struct pbuf * p)230 rfc7668_compress(struct netif *netif, struct pbuf *p)
231 {
232 struct pbuf *p_frag;
233 u16_t remaining_len;
234 u8_t *buffer;
235 u8_t lowpan6_header_len;
236 u8_t hidden_header_len;
237 err_t err;
238
239 LWIP_ASSERT("lowpan6_frag: netif->linkoutput not set", netif->linkoutput != NULL);
240
241 #if LWIP_6LOWPAN_IPHC
242
243 /* We'll use a dedicated pbuf for building BLE fragments.
244 * We'll over-allocate it by the bytes saved for header compression.
245 */
246 p_frag = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
247 if (p_frag == NULL) {
248 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
249 return ERR_MEM;
250 }
251 LWIP_ASSERT("this needs a pbuf in one piece", p_frag->len == p_frag->tot_len);
252
253 /* Write IP6 header (with IPHC). */
254 buffer = (u8_t*)p_frag->payload;
255
256 err = lowpan6_compress_headers(netif, (u8_t *)p->payload, p->len, buffer, p_frag->len,
257 &lowpan6_header_len, &hidden_header_len, rfc7668_context, &rfc7668_local_addr, &rfc7668_peer_addr);
258 if (err != ERR_OK) {
259 MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
260 pbuf_free(p_frag);
261 return err;
262 }
263 pbuf_remove_header(p, hidden_header_len);
264
265 /* Calculate remaining packet length */
266 remaining_len = p->tot_len;
267
268 /* Copy IPv6 packet */
269 pbuf_copy_partial(p, buffer + lowpan6_header_len, remaining_len, 0);
270
271 /* Calculate frame length */
272 p_frag->len = p_frag->tot_len = remaining_len + lowpan6_header_len;
273
274 /* send the packet */
275 MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
276 LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG|LWIP_DBG_TRACE, ("rfc7668_output: sending packet %p\n", (void *)p));
277 err = netif->linkoutput(netif, p_frag);
278
279 pbuf_free(p_frag);
280
281 return err;
282 #else /* LWIP_6LOWPAN_IPHC */
283 /* 6LoWPAN over BLE requires IPHC! */
284 return ERR_IF;
285 #endif/* LWIP_6LOWPAN_IPHC */
286 }
287
288 /**
289 * @ingroup rfc7668if
290 * Set context id IPv6 address
291 *
292 * Store one IPv6 address to a given context id.
293 *
294 * @param idx Context id
295 * @param context IPv6 addr for this context
296 *
297 * @return ERR_OK (if everything is fine), ERR_ARG (if the context id is out of range), ERR_VAL (if contexts disabled)
298 */
299 err_t
rfc7668_set_context(u8_t idx,const ip6_addr_t * context)300 rfc7668_set_context(u8_t idx, const ip6_addr_t *context)
301 {
302 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
303 /* check if the ID is possible */
304 if (idx >= LWIP_6LOWPAN_NUM_CONTEXTS) {
305 return ERR_ARG;
306 }
307 /* copy IPv6 address to context storage */
308 ip6_addr_set(&rfc7668_context[idx], context);
309 return ERR_OK;
310 #else
311 LWIP_UNUSED_ARG(idx);
312 LWIP_UNUSED_ARG(context);
313 return ERR_VAL;
314 #endif
315 }
316
317 /**
318 * @ingroup rfc7668if
319 * Compress outgoing IPv6 packet and pass it on to netif->linkoutput
320 *
321 * @param netif The lwIP network interface which the IP packet will be sent on.
322 * @param q The pbuf(s) containing the IP packet to be sent.
323 * @param ip6addr The IP address of the packet destination.
324 *
325 * @return See rfc7668_compress
326 */
327 err_t
rfc7668_output(struct netif * netif,struct pbuf * q,const ip6_addr_t * ip6addr)328 rfc7668_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
329 {
330 /* dst ip6addr is not used here, we only have one peer */
331 LWIP_UNUSED_ARG(ip6addr);
332
333 return rfc7668_compress(netif, q);
334 }
335
336 /**
337 * @ingroup rfc7668if
338 * Process a received raw payload from an L2CAP channel
339 *
340 * @param p the received packet, p->payload pointing to the
341 * IPv6 header (maybe compressed)
342 * @param netif the network interface on which the packet was received
343 *
344 * @return ERR_OK if everything was fine
345 */
346 err_t
rfc7668_input(struct pbuf * p,struct netif * netif)347 rfc7668_input(struct pbuf * p, struct netif *netif)
348 {
349 u8_t * puc;
350
351 MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
352
353 /* Load first header byte */
354 puc = (u8_t*)p->payload;
355
356 /* no IP header compression */
357 if (*puc == 0x41) {
358 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, removing dispatch: 0x%2x \n", *puc));
359 /* This is a complete IPv6 packet, just skip header byte. */
360 pbuf_remove_header(p, 1);
361 /* IPHC header compression */
362 } else if ((*puc & 0xe0 )== 0x60) {
363 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, decompress dispatch: 0x%2x \n", *puc));
364 /* IPv6 headers are compressed using IPHC. */
365 p = lowpan6_decompress(p, 0, rfc7668_context, &rfc7668_peer_addr, &rfc7668_local_addr);
366 /* if no pbuf is returned, handle as discarded packet */
367 if (p == NULL) {
368 MIB2_STATS_NETIF_INC(netif, ifindiscards);
369 return ERR_OK;
370 }
371 /* invalid header byte, discard */
372 } else {
373 LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, discarding: 0x%2x \n", *puc));
374 MIB2_STATS_NETIF_INC(netif, ifindiscards);
375 pbuf_free(p);
376 return ERR_OK;
377 }
378 /* @todo: distinguish unicast/multicast */
379 MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
380
381 #if LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG
382 {
383 u16_t i;
384 LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("IPv6 payload:\n"));
385 for (i = 0; i < p->len; i++) {
386 if ((i%4)==0) {
387 LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("\n"));
388 }
389 LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("%2X ", *((uint8_t *)p->payload+i)));
390 }
391 LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("\np->len: %d\n", p->len));
392 }
393 #endif
394 /* pass data to ip6_input */
395 return ip6_input(p, netif);
396 }
397
398 /**
399 * @ingroup rfc7668if
400 * Initialize the netif
401 *
402 * No flags are used (broadcast not possible, not ethernet, ...)
403 * The shortname for this netif is "BT"
404 *
405 * @param netif the network interface to be initialized as RFC7668 netif
406 *
407 * @return ERR_OK if everything went fine
408 */
409 err_t
rfc7668_if_init(struct netif * netif)410 rfc7668_if_init(struct netif *netif)
411 {
412 netif->name[0] = 'b';
413 netif->name[1] = 't';
414 /* local function as IPv6 output */
415 netif->output_ip6 = rfc7668_output;
416
417 MIB2_INIT_NETIF(netif, snmp_ifType_other, 0);
418
419 /* maximum transfer unit, set according to RFC7668 ch2.4 */
420 netif->mtu = IP6_MIN_MTU_LENGTH;
421
422 /* no flags set (no broadcast, ethernet,...)*/
423 netif->flags = 0;
424
425 /* everything fine */
426 return ERR_OK;
427 }
428
429 #if !NO_SYS
430 /**
431 * Pass a received packet to tcpip_thread for input processing
432 *
433 * @param p the received packet, p->payload pointing to the
434 * IEEE 802.15.4 header.
435 * @param inp the network interface on which the packet was received
436 *
437 * @return see @ref tcpip_inpkt, same return values
438 */
439 err_t
tcpip_rfc7668_input(struct pbuf * p,struct netif * inp)440 tcpip_rfc7668_input(struct pbuf *p, struct netif *inp)
441 {
442 /* send data to upper layer, return the result */
443 return tcpip_inpkt(p, inp, rfc7668_input);
444 }
445 #endif /* !NO_SYS */
446
447 #endif /* LWIP_IPV6 */
448