lwip_lowpan6.c

00001 /**
00002   * @file
00003  *
00004  * 6LowPAN output for IPv6. Uses ND tables for link-layer addressing. Fragments packets to 6LowPAN units.
00005  */
00006 
00007 /*
00008  * Copyright (c) 2015 Inico Technologies Ltd.
00009  * All rights reserved.
00010  *
00011  * Redistribution and use in source and binary forms, with or without modification,
00012  * are permitted provided that the following conditions are met:
00013  *
00014  * 1. Redistributions of source code must retain the above copyright notice,
00015  *    this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright notice,
00017  *    this list of conditions and the following disclaimer in the documentation
00018  *    and/or other materials provided with the distribution.
00019  * 3. The name of the author may not be used to endorse or promote products
00020  *    derived from this software without specific prior written permission.
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00023  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00024  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00025  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00026  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00027  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00030  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00031  * OF SUCH DAMAGE.
00032  *
00033  * This file is part of the lwIP TCP/IP stack.
00034  *
00035  * Author: Ivan Delamer <delamer@inicotech.com>
00036  *
00037  *
00038  * Please coordinate changes and requests with Ivan Delamer
00039  * <delamer@inicotech.com>
00040  */
00041 
00042 /**
00043  * @defgroup sixlowpan 6LowPAN netif
00044  * @ingroup addons
00045  * 6LowPAN netif implementation
00046  */
00047 
00048 #include "netif/lowpan6.h"
00049 
00050 #if LWIP_IPV6 && LWIP_6LOWPAN
00051 
00052 #include "lwip/ip.h"
00053 #include "lwip/pbuf.h"
00054 #include "lwip/ip_addr.h"
00055 #include "lwip/netif.h"
00056 #include "lwip/nd6.h"
00057 #include "lwip/mem.h"
00058 #include "lwip/udp.h"
00059 #include "lwip/tcpip.h"
00060 #include "lwip/snmp.h"
00061 
00062 #include <string.h>
00063 
00064 struct ieee_802154_addr {
00065   u8_t addr_len;
00066   u8_t addr[8];
00067 };
00068 
00069 /** This is a helper struct.
00070  */
00071 struct lowpan6_reass_helper {
00072   struct pbuf *pbuf;
00073   struct lowpan6_reass_helper *next_packet;
00074   u8_t timer;
00075   struct ieee_802154_addr sender_addr;
00076   u16_t datagram_size;
00077   u16_t datagram_tag;
00078 };
00079 
00080 static struct lowpan6_reass_helper * reass_list;
00081 
00082 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
00083 static ip6_addr_t lowpan6_context[LWIP_6LOWPAN_NUM_CONTEXTS];
00084 #endif
00085 
00086 static u16_t ieee_802154_pan_id;
00087 
00088 static const struct ieee_802154_addr ieee_802154_broadcast = {2, {0xff, 0xff}};
00089 
00090 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
00091 static struct ieee_802154_addr short_mac_addr = {2, {0,0}};
00092 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
00093 
00094 static err_t dequeue_datagram(struct lowpan6_reass_helper *lrh);
00095 
00096 /**
00097  * Periodic timer for 6LowPAN functions:
00098  *
00099  * - Remove incomplete/old packets
00100  */
00101 void
00102 lowpan6_tmr(void)
00103 {
00104   struct lowpan6_reass_helper *lrh, *lrh_temp;
00105 
00106   lrh = reass_list;
00107   while (lrh != NULL) {
00108     lrh_temp = lrh->next_packet;
00109     if ((--lrh->timer) == 0) {
00110       dequeue_datagram(lrh);
00111       pbuf_free(lrh->pbuf);
00112       mem_free(lrh);
00113     }
00114     lrh = lrh_temp;
00115   }
00116 }
00117 
00118 /**
00119  * Removes a datagram from the reassembly queue.
00120  **/
00121 static err_t
00122 dequeue_datagram(struct lowpan6_reass_helper *lrh)
00123 {
00124   struct lowpan6_reass_helper *lrh_temp;
00125 
00126   if (reass_list == lrh) {
00127     reass_list = reass_list->next_packet;
00128   } else {
00129     lrh_temp = reass_list;
00130     while (lrh_temp != NULL) {
00131       if (lrh_temp->next_packet == lrh) {
00132         lrh_temp->next_packet = lrh->next_packet;
00133         break;
00134       }
00135       lrh_temp = lrh_temp->next_packet;
00136     }
00137   }
00138 
00139   return ERR_OK;
00140 }
00141 
00142 static s8_t
00143 lowpan6_context_lookup(const ip6_addr_t *ip6addr)
00144 {
00145   s8_t i;
00146 
00147   for (i = 0; i < LWIP_6LOWPAN_NUM_CONTEXTS; i++) {
00148     if (ip6_addr_netcmp(&lowpan6_context[i], ip6addr)) {
00149       return i;
00150     }
00151   }
00152 
00153   return -1;
00154 }
00155 
00156 /* Determine compression mode for unicast address. */
00157 static s8_t
00158 lowpan6_get_address_mode(const ip6_addr_t *ip6addr, const struct ieee_802154_addr *mac_addr)
00159 {
00160   if (mac_addr->addr_len == 2) {
00161     if ((ip6addr->addr[2] == (u32_t)PP_HTONL(0x000000ff)) &&
00162       ((ip6addr->addr[3]  & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000))) {
00163       if ((ip6addr->addr[3]  & PP_HTONL(0x0000ffff)) == ntohl((mac_addr->addr[0] << 8) | mac_addr->addr[1])) {
00164         return 3;
00165       }
00166     }
00167   } else if (mac_addr->addr_len == 8) {
00168     if ((ip6addr->addr[2] == ntohl(((mac_addr->addr[0] ^ 2) << 24) | (mac_addr->addr[1] << 16) | mac_addr->addr[2] << 8 | mac_addr->addr[3])) &&
00169       (ip6addr->addr[3] == ntohl((mac_addr->addr[4] << 24) | (mac_addr->addr[5] << 16) | mac_addr->addr[6] << 8 | mac_addr->addr[7]))) {
00170       return 3;
00171     }
00172   }
00173 
00174   if ((ip6addr->addr[2] == PP_HTONL(0x000000ffUL)) &&
00175     ((ip6addr->addr[3]  & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000UL))) {
00176     return 2;
00177   }
00178 
00179   return 1;
00180 }
00181 
00182 /* Determine compression mode for multicast address. */
00183 static s8_t
00184 lowpan6_get_address_mode_mc(const ip6_addr_t *ip6addr)
00185 {
00186   if ((ip6addr->addr[0] == PP_HTONL(0xff020000)) &&
00187       (ip6addr->addr[1] == 0) &&
00188       (ip6addr->addr[2] == 0) &&
00189       ((ip6addr->addr[3]  & PP_HTONL(0xffffff00)) == 0)) {
00190     return 3;
00191   } else if (((ip6addr->addr[0] & PP_HTONL(0xff00ffff)) == PP_HTONL(0xff000000)) &&
00192               (ip6addr->addr[1] == 0)) {
00193     if ((ip6addr->addr[2] == 0) &&
00194         ((ip6addr->addr[3]  & PP_HTONL(0xff000000)) == 0)) {
00195       return 2;
00196     } else if ((ip6addr->addr[2]  & PP_HTONL(0xffffff00)) == 0) {
00197       return 1;
00198     }
00199   }
00200 
00201   return 0;
00202 }
00203 
00204 /*
00205  * Encapsulates data into IEEE 802.15.4 frames.
00206  * Fragments an IPv6 datagram into 6LowPAN units, which fit into IEEE 802.15.4 frames.
00207  * If configured, will compress IPv6 and or UDP headers.
00208  * */
00209 static err_t
00210 lowpan6_frag(struct netif *netif, struct pbuf *p, const struct ieee_802154_addr *src, const struct ieee_802154_addr *dst)
00211 {
00212   struct pbuf * p_frag;
00213   u16_t frag_len, remaining_len;
00214   u8_t * buffer;
00215   u8_t ieee_header_len;
00216   u8_t lowpan6_header_len;
00217   s8_t i;
00218   static u8_t frame_seq_num;
00219   static u16_t datagram_tag;
00220   u16_t datagram_offset;
00221   err_t err = ERR_IF;
00222 
00223   /* We'll use a dedicated pbuf for building 6LowPAN fragments. */
00224   p_frag = pbuf_alloc(PBUF_RAW, 127, PBUF_RAM);
00225   if (p_frag == NULL) {
00226     MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
00227     return ERR_MEM;
00228   }
00229 
00230   /* Write IEEE 802.15.4 header. */
00231   buffer  = (u8_t*)p_frag->payload;
00232   ieee_header_len = 0;
00233   if (dst == &ieee_802154_broadcast) {
00234     buffer[ieee_header_len++] = 0x01; /* data packet, no ack required. */
00235   } else {
00236     buffer[ieee_header_len++] = 0x21; /* data packet, ack required. */
00237   }
00238   buffer[ieee_header_len] = (0x00 << 4); /* 2003 frame version */
00239   buffer[ieee_header_len] |= (dst->addr_len == 2) ? (0x02 << 2) : (0x03 << 2); /* destination addressing mode  */
00240   buffer[ieee_header_len] |= (src->addr_len == 2) ? (0x02 << 6) : (0x03 << 6); /* source addressing mode */
00241   ieee_header_len++;
00242   buffer[ieee_header_len++] = frame_seq_num++;
00243 
00244   buffer[ieee_header_len++] = ieee_802154_pan_id & 0xff; /* pan id */
00245   buffer[ieee_header_len++] = (ieee_802154_pan_id >> 8) & 0xff; /* pan id */
00246   i = dst->addr_len;
00247   while (i-- > 0) {
00248     buffer[ieee_header_len++] = dst->addr[i];
00249   }
00250 
00251   buffer[ieee_header_len++] = ieee_802154_pan_id & 0xff; /* pan id */
00252   buffer[ieee_header_len++] = (ieee_802154_pan_id >> 8) & 0xff; /* pan id */
00253   i = src->addr_len;
00254   while (i-- > 0) {
00255     buffer[ieee_header_len++] = src->addr[i];
00256   }
00257 
00258 #if LWIP_6LOWPAN_IPHC
00259   /* Perform 6LowPAN IPv6 header compression according to RFC 6282 */
00260   {
00261     struct ip6_hdr *ip6hdr;
00262 
00263     /* Point to ip6 header and align copies of src/dest addresses. */
00264     ip6hdr = (struct ip6_hdr *)p->payload;
00265     ip_addr_copy_from_ip6(ip_data.current_iphdr_dest, ip6hdr->dest);
00266     ip_addr_copy_from_ip6(ip_data.current_iphdr_src, ip6hdr->src);
00267 
00268     /* Basic length of 6LowPAN header, set dispatch and clear fields. */
00269     lowpan6_header_len = 2;
00270     buffer[ieee_header_len] = 0x60;
00271     buffer[ieee_header_len + 1] = 0;
00272 
00273     /* Determine whether there will be a Context Identifier Extension byte or not.
00274     * If so, set it already. */
00275 #if LWIP_6LOWPAN_NUM_CONTEXTS > 0
00276     buffer[ieee_header_len + 2] = 0;
00277 
00278     i = lowpan6_context_lookup(ip_2_ip6(&ip_data.current_iphdr_src));
00279     if (i >= 0) {
00280       /* Stateful source address compression. */
00281       buffer[ieee_header_len + 1] |= 0x40;
00282       buffer[ieee_header_len + 2] |= (i & 0x0f) << 4;
00283     }
00284 
00285     i = lowpan6_context_lookup(ip_2_ip6(&ip_data.current_iphdr_dest));
00286     if (i >= 0) {
00287       /* Stateful destination address compression. */
00288       buffer[ieee_header_len + 1] |= 0x04;
00289       buffer[ieee_header_len + 2] |= i & 0x0f;
00290     }
00291 
00292     if (buffer[ieee_header_len + 2] != 0x00) {
00293       /* Context identifier extension byte is appended. */
00294       buffer[ieee_header_len + 1] |= 0x80;
00295       lowpan6_header_len++;
00296     }
00297 #endif /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */
00298 
00299     /* Determine TF field: Traffic Class, Flow Label */
00300     if (IP6H_FL(ip6hdr) == 0) {
00301       /* Flow label is elided. */
00302       buffer[ieee_header_len] |= 0x10;
00303       if (IP6H_TC(ip6hdr) == 0) {
00304         /* Traffic class (ECN+DSCP) elided too. */
00305         buffer[ieee_header_len] |= 0x08;
00306       } else {
00307         /* Traffic class (ECN+DSCP) appended. */
00308         buffer[ieee_header_len + lowpan6_header_len++] = IP6H_TC(ip6hdr);
00309       }
00310     } else {
00311       if (((IP6H_TC(ip6hdr) & 0x3f) == 0)) {
00312         /* DSCP portion of Traffic Class is elided, ECN and FL are appended (3 bytes) */
00313         buffer[ieee_header_len] |= 0x08;
00314 
00315         buffer[ieee_header_len + lowpan6_header_len] = IP6H_TC(ip6hdr) & 0xc0;
00316         buffer[ieee_header_len + lowpan6_header_len++] |= (IP6H_FL(ip6hdr) >> 16) & 0x0f;
00317         buffer[ieee_header_len + lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff;
00318         buffer[ieee_header_len + lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff;
00319       } else {
00320         /* Traffic class and flow label are appended (4 bytes) */
00321         buffer[ieee_header_len + lowpan6_header_len++] = IP6H_TC(ip6hdr);
00322         buffer[ieee_header_len + lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 16) & 0x0f;
00323         buffer[ieee_header_len + lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff;
00324         buffer[ieee_header_len + lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff;
00325       }
00326     }
00327 
00328     /* Compress NH?
00329     * Only if UDP for now. @todo support other NH compression. */
00330     if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) {
00331       buffer[ieee_header_len] |= 0x04;
00332     } else {
00333       /* append nexth. */
00334       buffer[ieee_header_len + lowpan6_header_len++] = IP6H_NEXTH(ip6hdr);
00335     }
00336 
00337     /* Compress hop limit? */
00338     if (IP6H_HOPLIM(ip6hdr) == 255) {
00339       buffer[ieee_header_len] |= 0x03;
00340     } else if (IP6H_HOPLIM(ip6hdr) == 64) {
00341       buffer[ieee_header_len] |= 0x02;
00342     } else if (IP6H_HOPLIM(ip6hdr) == 1) {
00343       buffer[ieee_header_len] |= 0x01;
00344     } else {
00345       /* append hop limit */
00346       buffer[ieee_header_len + lowpan6_header_len++] = IP6H_HOPLIM(ip6hdr);
00347     }
00348 
00349     /* Compress source address */
00350     if (((buffer[ieee_header_len + 1] & 0x40) != 0) ||
00351         (ip6_addr_islinklocal(ip_2_ip6(&ip_data.current_iphdr_src)))) {
00352       /* Context-based or link-local source address compression. */
00353       i = lowpan6_get_address_mode(ip_2_ip6(&ip_data.current_iphdr_src), src);
00354       buffer[ieee_header_len + 1] |= (i & 0x03) << 4;
00355       if (i == 1) {
00356         MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 16, 8);
00357         lowpan6_header_len += 8;
00358       } else if (i == 2) {
00359         MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 22, 2);
00360         lowpan6_header_len += 2;
00361       }
00362     } else if (ip6_addr_isany(ip_2_ip6(&ip_data.current_iphdr_src))) {
00363       /* Special case: mark SAC and leave SAM=0 */
00364       buffer[ieee_header_len + 1] |= 0x40;
00365     } else {
00366       /* Append full address. */
00367       MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 8, 16);
00368       lowpan6_header_len += 16;
00369     }
00370 
00371     /* Compress destination address */
00372     if (ip6_addr_ismulticast(ip_2_ip6(&ip_data.current_iphdr_dest))) {
00373       /* @todo support stateful multicast address compression */
00374 
00375       buffer[ieee_header_len + 1] |= 0x08;
00376 
00377       i = lowpan6_get_address_mode_mc(ip_2_ip6(&ip_data.current_iphdr_dest));
00378       buffer[ieee_header_len + 1] |= i & 0x03;
00379       if (i == 0) {
00380         MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 24, 16);
00381         lowpan6_header_len += 16;
00382       } else if (i == 1) {
00383         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[25];
00384         MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 35, 5);
00385         lowpan6_header_len += 5;
00386       } else if (i == 2) {
00387         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[25];
00388         MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 37, 3);
00389         lowpan6_header_len += 3;
00390       } else if (i == 3) {
00391         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[39];
00392       }
00393     } else if (((buffer[ieee_header_len + 1] & 0x04) != 0) ||
00394                (ip6_addr_islinklocal(ip_2_ip6(&ip_data.current_iphdr_dest)))) {
00395       /* Context-based or link-local destination address compression. */
00396       i = lowpan6_get_address_mode(ip_2_ip6(&ip_data.current_iphdr_dest), dst);
00397       buffer[ieee_header_len + 1] |= i & 0x03;
00398       if (i == 1) {
00399         MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 32, 8);
00400         lowpan6_header_len += 8;
00401       } else if (i == 2) {
00402         MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 38, 2);
00403         lowpan6_header_len += 2;
00404       }
00405     } else {
00406       /* Append full address. */
00407       MEMCPY(buffer + ieee_header_len + lowpan6_header_len, (u8_t*)p->payload + 24, 16);
00408       lowpan6_header_len += 16;
00409     }
00410 
00411     /* Move to payload. */
00412     pbuf_header(p, -IP6_HLEN);
00413 
00414     /* Compress UDP header? */
00415     if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) {
00416       /* @todo support optional checksum compression */
00417 
00418       buffer[ieee_header_len + lowpan6_header_len] = 0xf0;
00419 
00420       /* determine port compression mode. */
00421       if ((((u8_t *)p->payload)[0] == 0xf0) && ((((u8_t *)p->payload)[1] & 0xf0) == 0xb0) &&
00422           (((u8_t *)p->payload)[2] == 0xf0) && ((((u8_t *)p->payload)[3] & 0xf0) == 0xb0)) {
00423         /* Compress source and dest ports. */
00424         buffer[ieee_header_len + lowpan6_header_len++] |= 0x03;
00425         buffer[ieee_header_len + lowpan6_header_len++] = ((((u8_t *)p->payload)[1] & 0x0f) << 4) | (((u8_t *)p->payload)[3] & 0x0f);
00426       } else if (((u8_t *)p->payload)[0] == 0xf0) {
00427         /* Compress source port. */
00428         buffer[ieee_header_len + lowpan6_header_len++] |= 0x02;
00429         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[1];
00430         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[2];
00431         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[3];
00432       } else if (((u8_t *)p->payload)[2] == 0xf0) {
00433         /* Compress dest port. */
00434         buffer[ieee_header_len + lowpan6_header_len++] |= 0x01;
00435         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[0];
00436         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[1];
00437         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[3];
00438       } else {
00439         /* append full ports. */
00440         lowpan6_header_len++;
00441         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[0];
00442         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[1];
00443         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[2];
00444         buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[3];
00445       }
00446 
00447       /* elide length and copy checksum */
00448       buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[6];
00449       buffer[ieee_header_len + lowpan6_header_len++] = ((u8_t *)p->payload)[7];
00450 
00451       pbuf_header(p, -UDP_HLEN);
00452     }
00453   }
00454 
00455 #else /* LWIP_6LOWPAN_HC */
00456   /* Send uncompressed IPv6 header with appropriate dispatch byte. */
00457   lowpan6_header_len = 1;
00458   buffer[ieee_header_len] = 0x41; /* IPv6 dispatch */
00459 #endif /* LWIP_6LOWPAN_HC */
00460 
00461   /* Calculate remaining packet length */
00462   remaining_len = p->tot_len;
00463 
00464   if (remaining_len > 0x7FF) {
00465     MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
00466     /* datagram_size must fit into 11 bit */
00467     pbuf_free(p_frag);
00468     return ERR_VAL;
00469   }
00470 
00471   /* Fragment, or 1 packet? */
00472   if (remaining_len > (127 - ieee_header_len - lowpan6_header_len - 3)) { /* 127 - header - 1 byte dispatch - 2 bytes CRC */
00473     /* We must move the 6LowPAN header to make room for the FRAG header. */
00474     i = lowpan6_header_len;
00475     while (i-- != 0) {
00476       buffer[ieee_header_len + i + 4] = buffer[ieee_header_len + i];
00477     }
00478 
00479     /* Now we need to fragment the packet. FRAG1 header first */
00480     buffer[ieee_header_len] = 0xc0 | (((p->tot_len + lowpan6_header_len) >> 8) & 0x7);
00481     buffer[ieee_header_len + 1] = (p->tot_len + lowpan6_header_len) & 0xff;
00482 
00483     datagram_tag++;
00484     buffer[ieee_header_len + 2] = datagram_tag & 0xff;
00485     buffer[ieee_header_len + 3] = (datagram_tag >> 8) & 0xff;
00486 
00487     /* Fragment follows. */
00488     frag_len = (127 - ieee_header_len - 4 - 2) & 0xf8;
00489 
00490     pbuf_copy_partial(p, buffer + ieee_header_len + lowpan6_header_len + 4, frag_len - lowpan6_header_len, 0);
00491     remaining_len -= frag_len - lowpan6_header_len;
00492     datagram_offset = frag_len;
00493 
00494     /* 2 bytes CRC */
00495 #if LWIP_6LOWPAN_HW_CRC
00496     /* Leave blank, will be filled by HW. */
00497 #else /* LWIP_6LOWPAN_HW_CRC */
00498     /* @todo calculate CRC */
00499 #endif /* LWIP_6LOWPAN_HW_CRC */
00500 
00501     /* Calculate frame length */
00502     p_frag->len = p_frag->tot_len = ieee_header_len + 4 + frag_len + 2; /* add 2 dummy bytes for crc*/
00503 
00504     /* send the packet */
00505     MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
00506     LWIP_DEBUGF(LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
00507     err = netif->linkoutput(netif, p_frag);
00508 
00509     while ((remaining_len > 0) && (err == ERR_OK)) {
00510       /* new frame, new seq num for ACK */
00511       buffer[2] = frame_seq_num++;
00512 
00513       buffer[ieee_header_len] |= 0x20; /* Change FRAG1 to FRAGN */
00514 
00515       buffer[ieee_header_len + 4] = (u8_t)(datagram_offset >> 3); /* datagram offset in FRAGN header (datagram_offset is max. 11 bit) */
00516 
00517       frag_len = (127 - ieee_header_len - 5 - 2) & 0xf8;
00518       if (frag_len > remaining_len) {
00519         frag_len = remaining_len;
00520       }
00521 
00522       pbuf_copy_partial(p, buffer + ieee_header_len + 5, frag_len, p->tot_len - remaining_len);
00523       remaining_len -= frag_len;
00524       datagram_offset += frag_len;
00525 
00526       /* 2 bytes CRC */
00527 #if LWIP_6LOWPAN_HW_CRC
00528       /* Leave blank, will be filled by HW. */
00529 #else /* LWIP_6LOWPAN_HW_CRC */
00530       /* @todo calculate CRC */
00531 #endif /* LWIP_6LOWPAN_HW_CRC */
00532 
00533       /* Calculate frame length */
00534       p_frag->len = p_frag->tot_len = frag_len + 5 + ieee_header_len + 2;
00535 
00536       /* send the packet */
00537       MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
00538       LWIP_DEBUGF(LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
00539       err = netif->linkoutput(netif, p_frag);
00540     }
00541   } else {
00542     /* It fits in one frame. */
00543     frag_len = remaining_len;
00544 
00545     /* Copy IPv6 packet */
00546     pbuf_copy_partial(p, buffer + ieee_header_len + lowpan6_header_len, frag_len, 0);
00547     remaining_len = 0;
00548 
00549     /* 2 bytes CRC */
00550 #if LWIP_6LOWPAN_HW_CRC
00551     /* Leave blank, will be filled by HW. */
00552 #else /* LWIP_6LOWPAN_HW_CRC */
00553     /* @todo calculate CRC */
00554 #endif /* LWIP_6LOWPAN_HW_CRC */
00555 
00556     /* Calculate frame length */
00557     p_frag->len = p_frag->tot_len = frag_len + lowpan6_header_len + ieee_header_len + 2;
00558 
00559     /* send the packet */
00560     MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
00561     LWIP_DEBUGF(LOWPAN6_DEBUG | LWIP_DBG_TRACE, ("lowpan6_send: sending packet %p\n", (void *)p));
00562     err = netif->linkoutput(netif, p_frag);
00563   }
00564 
00565   pbuf_free(p_frag);
00566 
00567   return err;
00568 }
00569 
00570 err_t
00571 lowpan6_set_context(u8_t idx, const ip6_addr_t * context)
00572 {
00573   if (idx >= LWIP_6LOWPAN_NUM_CONTEXTS) {
00574     return ERR_ARG;
00575   }
00576 
00577   ip6_addr_set(&lowpan6_context[idx], context);
00578 
00579   return ERR_OK;
00580 }
00581 
00582 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
00583 err_t
00584 lowpan6_set_short_addr(u8_t addr_high, u8_t addr_low)
00585 {
00586   short_mac_addr.addr[0] = addr_high;
00587   short_mac_addr.addr[1] = addr_low;
00588 
00589   return ERR_OK;
00590 }
00591 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
00592 
00593 #if LWIP_IPV4
00594 err_t
00595 lowpan4_output(struct netif *netif, struct pbuf *q, const ip4_addr_t *ipaddr)
00596 {
00597   (void)netif;
00598   (void)q;
00599   (void)ipaddr;
00600 
00601   return ERR_IF;
00602 }
00603 #endif /* LWIP_IPV4 */
00604 
00605 /**
00606  * Resolve and fill-in IEEE 802.15.4 address header for outgoing IPv6 packet.
00607  *
00608  * Perform Header Compression and fragment if necessary.
00609  *
00610  * @param netif The lwIP network interface which the IP packet will be sent on.
00611  * @param q The pbuf(s) containing the IP packet to be sent.
00612  * @param ip6addr The IP address of the packet destination.
00613  *
00614  * @return
00615  */
00616 err_t
00617 lowpan6_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
00618 {
00619   s8_t i;
00620   struct ieee_802154_addr src, dest;
00621 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
00622   ip6_addr_t ip6_src;
00623   struct ip6_hdr * ip6_hdr;
00624 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
00625 
00626 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
00627   /* Check if we can compress source address (use aligned copy) */
00628   ip6_hdr = (struct ip6_hdr *)q->payload;
00629   ip6_addr_set(&ip6_src, &ip6_hdr->src);
00630   if (lowpan6_get_address_mode(&ip6_src, &short_mac_addr) == 3) {
00631     src.addr_len = 2;
00632     src.addr[0] = short_mac_addr.addr[0];
00633     src.addr[1] = short_mac_addr.addr[1];
00634   } else
00635 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
00636   {
00637     src.addr_len = netif->hwaddr_len;
00638     SMEMCPY(src.addr, netif->hwaddr, netif->hwaddr_len);
00639   }
00640 
00641   /* multicast destination IP address? */
00642   if (ip6_addr_ismulticast(ip6addr)) {
00643     MIB2_STATS_NETIF_INC(netif, ifoutnucastpkts);
00644     /* We need to send to the broadcast address.*/
00645     return lowpan6_frag(netif, q, &src, &ieee_802154_broadcast);
00646   }
00647 
00648   /* We have a unicast destination IP address */
00649   /* @todo anycast? */
00650 
00651 #if LWIP_6LOWPAN_INFER_SHORT_ADDRESS
00652   if (src.addr_len == 2) {
00653     /* If source address was compressable to short_mac_addr, and dest has same subnet and
00654     * is also compressable to 2-bytes, assume we can infer dest as a short address too. */
00655     dest.addr_len = 2;
00656     dest.addr[0] = ((u8_t *)q->payload)[38];
00657     dest.addr[1] = ((u8_t *)q->payload)[39];
00658     if ((src.addr_len == 2) && (ip6_addr_netcmp(&ip6_hdr->src, &ip6_hdr->dest)) &&
00659         (lowpan6_get_address_mode(ip6addr, &dest) == 3)) {
00660       MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
00661       return lowpan6_frag(netif, q, &src, &dest);
00662     }
00663   }
00664 #endif /* LWIP_6LOWPAN_INFER_SHORT_ADDRESS */
00665 
00666 
00667   /* Get next hop record. */
00668   i = nd6_get_next_hop_entry(ip6addr, netif);
00669   if (i < 0) {
00670     MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
00671     /* failed to get a next hop neighbor record. */
00672     return ERR_MEM;
00673   }
00674 
00675   /* Now that we have a destination record, send or queue the packet. */
00676   if (neighbor_cache[i].state == ND6_STALE) {
00677     /* Switch to delay state. */
00678     neighbor_cache[i].state = ND6_DELAY;
00679     neighbor_cache[i].counter.delay_time = LWIP_ND6_DELAY_FIRST_PROBE_TIME;
00680   }
00681   /* @todo should we send or queue if PROBE? send for now, to let unicast NS pass. */
00682   if ((neighbor_cache[i].state == ND6_REACHABLE) ||
00683       (neighbor_cache[i].state == ND6_DELAY) ||
00684       (neighbor_cache[i].state == ND6_PROBE)) {
00685 
00686     /* Send out. */
00687     dest.addr_len = netif->hwaddr_len;
00688     SMEMCPY(dest.addr, neighbor_cache[i].lladdr, netif->hwaddr_len);
00689     MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
00690     return lowpan6_frag(netif, q, &src, &dest);
00691   }
00692 
00693   /* We should queue packet on this interface. */
00694   return nd6_queue_packet(i, q);
00695 }
00696 
00697 static struct pbuf *
00698 lowpan6_decompress(struct pbuf * p, struct ieee_802154_addr * src, struct ieee_802154_addr * dest)
00699 {
00700   struct pbuf * q;
00701   u8_t * lowpan6_buffer;
00702   s8_t lowpan6_offset;
00703   struct ip6_hdr *ip6hdr;
00704   s8_t i;
00705   s8_t ip6_offset = IP6_HLEN;
00706 
00707 
00708   q = pbuf_alloc(PBUF_IP, p->len + IP6_HLEN + UDP_HLEN, PBUF_POOL);
00709   if (q == NULL) {
00710     pbuf_free(p);
00711     return NULL;
00712   }
00713 
00714   lowpan6_buffer = (u8_t *)p->payload;
00715   ip6hdr = (struct ip6_hdr *)q->payload;
00716 
00717   lowpan6_offset = 2;
00718   if (lowpan6_buffer[1] & 0x80) {
00719     lowpan6_offset++;
00720   }
00721 
00722   /* Set IPv6 version, traffic class and flow label. */
00723   if ((lowpan6_buffer[0] & 0x18) == 0x00) {
00724     IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset], ((lowpan6_buffer[lowpan6_offset+1] & 0x0f) << 16) | (lowpan6_buffer[lowpan6_offset + 2] << 8) | lowpan6_buffer[lowpan6_offset+3]);
00725     lowpan6_offset += 4;
00726   } else if ((lowpan6_buffer[0] & 0x18) == 0x08) {
00727     IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset] & 0xc0, ((lowpan6_buffer[lowpan6_offset] & 0x0f) << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset+2]);
00728     lowpan6_offset += 3;
00729   } else if ((lowpan6_buffer[0] & 0x18) == 0x10) {
00730     IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset],0);
00731     lowpan6_offset += 1;
00732   } else if ((lowpan6_buffer[0] & 0x18) == 0x18) {
00733     IP6H_VTCFL_SET(ip6hdr, 6, 0, 0);
00734   }
00735 
00736   /* Set Next Header */
00737   if ((lowpan6_buffer[0] & 0x04) == 0x00) {
00738     IP6H_NEXTH_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]);
00739   } else {
00740     /* We should fill this later with NHC decoding */
00741     IP6H_NEXTH_SET(ip6hdr, 0);
00742   }
00743 
00744   /* Set Hop Limit */
00745   if ((lowpan6_buffer[0] & 0x03) == 0x00) {
00746     IP6H_HOPLIM_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]);
00747   } else if ((lowpan6_buffer[0] & 0x03) == 0x01) {
00748     IP6H_HOPLIM_SET(ip6hdr, 1);
00749   } else if ((lowpan6_buffer[0] & 0x03) == 0x02) {
00750     IP6H_HOPLIM_SET(ip6hdr, 64);
00751   } else if ((lowpan6_buffer[0] & 0x03) == 0x03) {
00752     IP6H_HOPLIM_SET(ip6hdr, 255);
00753   }
00754 
00755   /* Source address decoding. */
00756   if ((lowpan6_buffer[1] & 0x40) == 0x00) {
00757     /* Stateless compression */
00758     if ((lowpan6_buffer[1] & 0x30) == 0x00) {
00759       /* copy full address */
00760       MEMCPY(&ip6hdr->src.addr[0], lowpan6_buffer + lowpan6_offset, 16);
00761       lowpan6_offset += 16;
00762     } else if ((lowpan6_buffer[1] & 0x30) == 0x10) {
00763       ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL);
00764       ip6hdr->src.addr[1] = 0;
00765       MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8);
00766       lowpan6_offset += 8;
00767     } else if ((lowpan6_buffer[1] & 0x30) == 0x20) {
00768       ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL);
00769       ip6hdr->src.addr[1] = 0;
00770       ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
00771       ip6hdr->src.addr[3] = htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) |
00772                                   lowpan6_buffer[lowpan6_offset+1]);
00773       lowpan6_offset += 2;
00774     } else if ((lowpan6_buffer[1] & 0x30) == 0x30) {
00775       ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL);
00776       ip6hdr->src.addr[1] = 0;
00777       if (src->addr_len == 2) {
00778         ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
00779         ip6hdr->src.addr[3] = htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]);
00780       } else {
00781         ip6hdr->src.addr[2] = htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) |
00782                                     (src->addr[2] << 8) | src->addr[3]);
00783         ip6hdr->src.addr[3] = htonl((src->addr[4] << 24) | (src->addr[5] << 16) |
00784                                     (src->addr[6] << 8) | src->addr[7]);
00785       }
00786     }
00787   } else {
00788     /* Stateful compression */
00789     if ((lowpan6_buffer[1] & 0x30) == 0x00) {
00790       /* ANY address */
00791       ip6hdr->src.addr[0] = 0;
00792       ip6hdr->src.addr[1] = 0;
00793       ip6hdr->src.addr[2] = 0;
00794       ip6hdr->src.addr[3] = 0;
00795     } else {
00796       /* Set prefix from context info */
00797       if (lowpan6_buffer[1] & 0x80) {
00798         i = (lowpan6_buffer[2] >> 4) & 0x0f;
00799       } else {
00800         i = 0;
00801       }
00802       if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
00803         /* Error */
00804         pbuf_free(p);
00805         pbuf_free(q);
00806         return NULL;
00807       }
00808 
00809       ip6hdr->src.addr[0] = lowpan6_context[i].addr[0];
00810       ip6hdr->src.addr[1] = lowpan6_context[i].addr[1];
00811     }
00812 
00813     if ((lowpan6_buffer[1] & 0x30) == 0x10) {
00814       MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8);
00815       lowpan6_offset += 8;
00816     } else if ((lowpan6_buffer[1] & 0x30) == 0x20) {
00817       ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
00818       ip6hdr->src.addr[3] = htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset+1]);
00819       lowpan6_offset += 2;
00820     } else if ((lowpan6_buffer[1] & 0x30) == 0x30) {
00821       if (src->addr_len == 2) {
00822         ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
00823         ip6hdr->src.addr[3] = htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]);
00824       } else {
00825         ip6hdr->src.addr[2] = htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) | (src->addr[2] << 8) | src->addr[3]);
00826         ip6hdr->src.addr[3] = htonl((src->addr[4] << 24) | (src->addr[5] << 16) | (src->addr[6] << 8) | src->addr[7]);
00827       }
00828     }
00829   }
00830 
00831   /* Destination address decoding. */
00832   if (lowpan6_buffer[1] & 0x08) {
00833     /* Multicast destination */
00834     if (lowpan6_buffer[1] & 0x04) {
00835       /* @todo support stateful multicast addressing */
00836       pbuf_free(p);
00837       pbuf_free(q);
00838       return NULL;
00839     }
00840 
00841     if ((lowpan6_buffer[1] & 0x03) == 0x00) {
00842       /* copy full address */
00843       MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16);
00844       lowpan6_offset += 16;
00845     } else if ((lowpan6_buffer[1] & 0x03) == 0x01) {
00846       ip6hdr->dest.addr[0] = htonl(0xff000000UL | (lowpan6_buffer[lowpan6_offset++] << 16));
00847       ip6hdr->dest.addr[1] = 0;
00848       ip6hdr->dest.addr[2] = htonl(lowpan6_buffer[lowpan6_offset++]);
00849       ip6hdr->dest.addr[3] = htonl((lowpan6_buffer[lowpan6_offset] << 24) | (lowpan6_buffer[lowpan6_offset + 1] << 16) | (lowpan6_buffer[lowpan6_offset + 2] << 8) | lowpan6_buffer[lowpan6_offset + 3]);
00850       lowpan6_offset += 4;
00851     } else if ((lowpan6_buffer[1] & 0x03) == 0x02) {
00852       ip6hdr->dest.addr[0] = htonl(0xff000000UL | lowpan6_buffer[lowpan6_offset++]);
00853       ip6hdr->dest.addr[1] = 0;
00854       ip6hdr->dest.addr[2] = 0;
00855       ip6hdr->dest.addr[3] = htonl((lowpan6_buffer[lowpan6_offset] << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset + 2]);
00856       lowpan6_offset += 3;
00857     } else if ((lowpan6_buffer[1] & 0x03) == 0x03) {
00858       ip6hdr->dest.addr[0] = PP_HTONL(0xff020000UL);
00859       ip6hdr->dest.addr[1] = 0;
00860       ip6hdr->dest.addr[2] = 0;
00861       ip6hdr->dest.addr[3] = htonl(lowpan6_buffer[lowpan6_offset++]);
00862     }
00863 
00864   } else {
00865     if (lowpan6_buffer[1] & 0x04) {
00866       /* Stateful destination compression */
00867       /* Set prefix from context info */
00868       if (lowpan6_buffer[1] & 0x80) {
00869         i = lowpan6_buffer[2] & 0x0f;
00870       } else {
00871         i = 0;
00872       }
00873       if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
00874         /* Error */
00875         pbuf_free(p);
00876         pbuf_free(q);
00877         return NULL;
00878       }
00879 
00880       ip6hdr->dest.addr[0] = lowpan6_context[i].addr[0];
00881       ip6hdr->dest.addr[1] = lowpan6_context[i].addr[1];
00882     } else {
00883       /* Link local address compression */
00884       ip6hdr->dest.addr[0] = PP_HTONL(0xfe800000UL);
00885       ip6hdr->dest.addr[1] = 0;
00886     }
00887 
00888     if ((lowpan6_buffer[1] & 0x03) == 0x00) {
00889       /* copy full address */
00890       MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16);
00891       lowpan6_offset += 16;
00892     } else if ((lowpan6_buffer[1] & 0x03) == 0x01) {
00893       MEMCPY(&ip6hdr->dest.addr[2], lowpan6_buffer + lowpan6_offset, 8);
00894       lowpan6_offset += 8;
00895     } else if ((lowpan6_buffer[1] & 0x03) == 0x02) {
00896       ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL);
00897       ip6hdr->dest.addr[3] = htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset + 1]);
00898       lowpan6_offset += 2;
00899     } else if ((lowpan6_buffer[1] & 0x03) == 0x03) {
00900       if (dest->addr_len == 2) {
00901         ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL);
00902         ip6hdr->dest.addr[3] = htonl(0xfe000000UL | (dest->addr[0] << 8) | dest->addr[1]);
00903       } else {
00904         ip6hdr->dest.addr[2] = htonl(((dest->addr[0] ^ 2) << 24) | (dest->addr[1] << 16) | dest->addr[2] << 8 | dest->addr[3]);
00905         ip6hdr->dest.addr[3] = htonl((dest->addr[4] << 24) | (dest->addr[5] << 16) | dest->addr[6] << 8 | dest->addr[7]);
00906       }
00907     }
00908   }
00909 
00910 
00911   /* Next Header Compression (NHC) decoding? */
00912   if (lowpan6_buffer[0] & 0x04) {
00913     if ((lowpan6_buffer[lowpan6_offset] & 0xf8) == 0xf0) {
00914       struct udp_hdr *udphdr;
00915 
00916       /* UDP compression */
00917       IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_UDP);
00918       udphdr = (struct udp_hdr *)((u8_t *)q->payload + ip6_offset);
00919 
00920       if (lowpan6_buffer[lowpan6_offset] & 0x04) {
00921         /* @todo support checksum decompress */
00922         pbuf_free(p);
00923         pbuf_free(q);
00924         return NULL;
00925       }
00926 
00927       /* Decompress ports */
00928       i = lowpan6_buffer[lowpan6_offset++] & 0x03;
00929       if (i == 0) {
00930         udphdr->src = htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
00931         udphdr->dest = htons(lowpan6_buffer[lowpan6_offset + 2] << 8 | lowpan6_buffer[lowpan6_offset + 3]);
00932         lowpan6_offset += 4;
00933       } else if (i == 0x01) {
00934         udphdr->src = htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
00935         udphdr->dest = htons(0xf000 | lowpan6_buffer[lowpan6_offset + 2]);
00936         lowpan6_offset += 3;
00937       } else if (i == 0x02) {
00938         udphdr->src = htons(0xf000 | lowpan6_buffer[lowpan6_offset]);
00939         udphdr->dest = htons(lowpan6_buffer[lowpan6_offset + 1] << 8 | lowpan6_buffer[lowpan6_offset + 2]);
00940         lowpan6_offset += 3;
00941       } else if (i == 0x03) {
00942         udphdr->src = htons(0xf0b0 | ((lowpan6_buffer[lowpan6_offset] >> 4) & 0x0f));
00943         udphdr->dest = htons(0xf0b0 | (lowpan6_buffer[lowpan6_offset] & 0x0f));
00944         lowpan6_offset += 1;
00945       }
00946 
00947       udphdr->chksum = htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
00948       lowpan6_offset += 2;
00949       udphdr->len = htons(p->tot_len - lowpan6_offset + UDP_HLEN);
00950 
00951       ip6_offset += UDP_HLEN;
00952     } else {
00953       /* @todo support NHC other than UDP */
00954       pbuf_free(p);
00955       pbuf_free(q);
00956       return NULL;
00957     }
00958   }
00959 
00960   /* Now we copy leftover contents from p to q, so we have all L2 and L3 headers (and L4?) in a single PBUF.
00961   * Replace p with q, and free p */
00962   pbuf_header(p, -lowpan6_offset);
00963   MEMCPY((u8_t*)q->payload + ip6_offset, p->payload, p->len);
00964   q->len = q->tot_len = ip6_offset + p->len;
00965   if (p->next != NULL) {
00966     pbuf_cat(q, p->next);
00967   }
00968   p->next = NULL;
00969   pbuf_free(p);
00970 
00971   /* Infer IPv6 payload length for header */
00972   IP6H_PLEN_SET(ip6hdr, q->tot_len - IP6_HLEN);
00973 
00974   /* all done */
00975   return q;
00976 }
00977 
00978 err_t
00979 lowpan6_input(struct pbuf * p, struct netif *netif)
00980 {
00981   u8_t * puc;
00982   s8_t i;
00983   struct ieee_802154_addr src, dest;
00984   u16_t datagram_size, datagram_offset, datagram_tag;
00985   struct lowpan6_reass_helper *lrh, *lrh_temp;
00986 
00987   MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
00988 
00989   /* Analyze header. @todo validate. */
00990   puc = (u8_t*)p->payload;
00991   datagram_offset = 5;
00992   if ((puc[1] & 0x0c) == 0x0c) {
00993     dest.addr_len = 8;
00994     for (i = 0; i < 8; i++) {
00995       dest.addr[i] = puc[datagram_offset + 7 - i];
00996     }
00997     datagram_offset += 8;
00998   } else {
00999     dest.addr_len = 2;
01000     dest.addr[0] = puc[datagram_offset + 1];
01001     dest.addr[1] = puc[datagram_offset];
01002     datagram_offset += 2;
01003   }
01004 
01005   datagram_offset += 2; /* skip PAN ID. */
01006 
01007   if ((puc[1] & 0xc0) == 0xc0) {
01008     src.addr_len = 8;
01009     for (i = 0; i < 8; i++) {
01010       src.addr[i] = puc[datagram_offset + 7 - i];
01011     }
01012     datagram_offset += 8;
01013   } else {
01014     src.addr_len = 2;
01015     src.addr[0] = puc[datagram_offset + 1];
01016     src.addr[1] = puc[datagram_offset];
01017     datagram_offset += 2;
01018   }
01019 
01020   pbuf_header(p, -datagram_offset); /* hide IEEE802.15.4 header. */
01021 
01022   /* Check dispatch. */
01023   puc = (u8_t*)p->payload;
01024 
01025   if ((*puc & 0xf8) == 0xc0) {
01026     /* FRAG1 dispatch. add this packet to reassembly list. */
01027     datagram_size = ((u16_t)(puc[0] & 0x07) << 8) | (u16_t)puc[1];
01028     datagram_tag = ((u16_t)puc[2] << 8) | (u16_t)puc[3];
01029 
01030     /* check for duplicate */
01031     lrh = reass_list;
01032     while (lrh != NULL) {
01033       if ((lrh->sender_addr.addr_len == src.addr_len) &&
01034           (memcmp(lrh->sender_addr.addr, src.addr, src.addr_len) == 0)) {
01035         /* address match with packet in reassembly. */
01036         if ((datagram_tag == lrh->datagram_tag) && (datagram_size == lrh->datagram_size)) {
01037           MIB2_STATS_NETIF_INC(netif, ifindiscards);
01038           /* duplicate fragment. */
01039           pbuf_free(p);
01040           return ERR_OK;
01041         } else {
01042           /* We are receiving the start of a new datagram. Discard old one (incomplete). */
01043           lrh_temp = lrh->next_packet;
01044           dequeue_datagram(lrh);
01045           pbuf_free(lrh->pbuf);
01046           mem_free(lrh);
01047 
01048           /* Check next datagram in queue. */
01049           lrh = lrh_temp;
01050         }
01051       } else {
01052         /* Check next datagram in queue. */
01053         lrh = lrh->next_packet;
01054       }
01055     }
01056 
01057     pbuf_header(p, -4); /* hide frag1 dispatch */
01058 
01059     lrh = (struct lowpan6_reass_helper *) mem_malloc(sizeof(struct lowpan6_reass_helper));
01060     if (lrh == NULL) {
01061       MIB2_STATS_NETIF_INC(netif, ifindiscards);
01062       pbuf_free(p);
01063       return ERR_MEM;
01064     }
01065 
01066     lrh->sender_addr.addr_len = src.addr_len;
01067     for (i = 0; i < src.addr_len; i++) {
01068       lrh->sender_addr.addr[i] = src.addr[i];
01069     }
01070     lrh->datagram_size = datagram_size;
01071     lrh->datagram_tag = datagram_tag;
01072     lrh->pbuf = p;
01073     lrh->next_packet = reass_list;
01074     lrh->timer = 2;
01075     reass_list = lrh;
01076 
01077     return ERR_OK;
01078   } else if ((*puc & 0xf8) == 0xe0) {
01079     /* FRAGN dispatch, find packet being reassembled. */
01080     datagram_size = ((u16_t)(puc[0] & 0x07) << 8) | (u16_t)puc[1];
01081     datagram_tag = ((u16_t)puc[2] << 8) | (u16_t)puc[3];
01082     datagram_offset = (u16_t)puc[4] << 3;
01083     pbuf_header(p, -5); /* hide frag1 dispatch */
01084 
01085     for (lrh = reass_list; lrh != NULL; lrh = lrh->next_packet) {
01086       if ((lrh->sender_addr.addr_len == src.addr_len) &&
01087           (memcmp(lrh->sender_addr.addr, src.addr, src.addr_len) == 0) &&
01088           (datagram_tag == lrh->datagram_tag) &&
01089           (datagram_size == lrh->datagram_size)) {
01090         break;
01091       }
01092     }
01093     if (lrh == NULL) {
01094       /* rogue fragment */
01095       MIB2_STATS_NETIF_INC(netif, ifindiscards);
01096       pbuf_free(p);
01097       return ERR_OK;
01098     }
01099 
01100     if (lrh->pbuf->tot_len < datagram_offset) {
01101       /* duplicate, ignore. */
01102       pbuf_free(p);
01103       return ERR_OK;
01104     } else if (lrh->pbuf->tot_len > datagram_offset) {
01105       MIB2_STATS_NETIF_INC(netif, ifindiscards);
01106       /* We have missed a fragment. Delete whole reassembly. */
01107       dequeue_datagram(lrh);
01108       pbuf_free(lrh->pbuf);
01109       mem_free(lrh);
01110       pbuf_free(p);
01111       return ERR_OK;
01112     }
01113     pbuf_cat(lrh->pbuf, p);
01114     p = NULL;
01115 
01116     /* is packet now complete?*/
01117     if (lrh->pbuf->tot_len >= lrh->datagram_size) {
01118       /* dequeue from reass list. */
01119       dequeue_datagram(lrh);
01120 
01121       /* get pbuf */
01122       p = lrh->pbuf;
01123 
01124       /* release helper */
01125       mem_free(lrh);
01126     } else {
01127       return ERR_OK;
01128     }
01129   }
01130 
01131   if (p == NULL) {
01132     return ERR_OK;
01133   }
01134 
01135   /* We have a complete packet, check dispatch for headers. */
01136   puc = (u8_t*)p->payload;
01137 
01138   if (*puc == 0x41) {
01139     /* This is a complete IPv6 packet, just skip dispatch byte. */
01140     pbuf_header(p, -1); /* hide dispatch byte. */
01141   } else if ((*puc & 0xe0 )== 0x60) {
01142     /* IPv6 headers are compressed using IPHC. */
01143     p = lowpan6_decompress(p, &src, &dest);
01144     if (p == NULL) {
01145       MIB2_STATS_NETIF_INC(netif, ifindiscards);
01146       return ERR_OK;
01147     }
01148   } else {
01149     MIB2_STATS_NETIF_INC(netif, ifindiscards);
01150     pbuf_free(p);
01151     return ERR_OK;
01152   }
01153 
01154   /* @todo: distinguish unicast/multicast */
01155   MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
01156 
01157   return ip6_input(p, netif);
01158 }
01159 
01160 err_t
01161 lowpan6_if_init(struct netif *netif)
01162 {
01163   netif->name[0] = 'L';
01164   netif->name[1] = '6';
01165 #if LWIP_IPV4
01166   netif->output = lowpan4_output;
01167 #endif /* LWIP_IPV4 */
01168   netif->output_ip6 = lowpan6_output;
01169 
01170   MIB2_INIT_NETIF(netif, snmp_ifType_other, 0);
01171 
01172   /* maximum transfer unit */
01173   netif->mtu = 1280;
01174 
01175   /* broadcast capability */
01176   netif->flags = NETIF_FLAG_BROADCAST /* | NETIF_FLAG_LOWPAN6 */;
01177 
01178   return ERR_OK;
01179 }
01180 
01181 err_t
01182 lowpan6_set_pan_id(u16_t pan_id)
01183 {
01184   ieee_802154_pan_id = pan_id;
01185 
01186   return ERR_OK;
01187 }
01188 
01189 #if !NO_SYS
01190 /**
01191  * Pass a received packet to tcpip_thread for input processing
01192  *
01193  * @param p the received packet, p->payload pointing to the
01194  *          IEEE 802.15.4 header.
01195  * @param inp the network interface on which the packet was received
01196  */
01197 err_t
01198 tcpip_6lowpan_input(struct pbuf *p, struct netif *inp)
01199 {
01200   return tcpip_inpkt(p, inp, lowpan6_input);
01201 }
01202 #endif /* !NO_SYS */
01203 
01204 #endif /* LWIP_IPV6 && LWIP_6LOWPAN */