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 110 ble_addr_to_eui64(u8_t *dst, const u8_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 139 eui64_to_ble_addr(u8_t *dst, const u8_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 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 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 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 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 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 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 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 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 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 ", *((u8_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 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 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