text: /**
   * \addtogroup sicslowpan
   * @{
   */
  /*
   * Copyright (c) 2008, Swedish Institute of Computer Science.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * This file is part of the Contiki operating system.
   *
   */
  /**
   * \file
   *         6lowpan implementation (RFC4944 and draft-ietf-6lowpan-hc-06)
   *
   * \author Adam Dunkels <adam@sics.se>
   * \author Nicolas Tsiftes <nvt@sics.se>
   * \author Niclas Finne <nfi@sics.se>
   * \author Mathilde Durvy <mdurvy@cisco.com>
   * \author Julien Abeille <jabeille@cisco.com>
   * \author Joakim Eriksson <joakime@sics.se>
   * \author Joel Hoglund <joel@sics.se>
   */
  
  /**
   * FOR HC-06 COMPLIANCE TODO:
   * -Add compression options to UDP, currently only supports
   *  both ports compressed or both ports elided
   *  
   * -Verify TC/FL compression works
   *  
   * -Add stateless multicast option
   */
  
  #include <string.h>
  
  #include "contiki.h"
  #include "dev/watchdog.h"
  #include "net/tcpip.h"
  #include "net/uip.h"
  #include "net/uip-ds6.h"
  #include "net/rime.h"
  #include "net/sicslowpan.h"
  #include "net/netstack.h"
  
  #if UIP_CONF_IPV6
  
  #include <stdio.h>
  
  #define DEBUG DEBUG_NONE
  #include "net/uip-debug.h"
  #if DEBUG
  /* PRINTFI and PRINTFO are defined for input and output to debug one without changing the timing of the other */
  uint8_t p;
  #include <stdio.h>
  #define PRINTFI(...) PRINTF(__VA_ARGS__)
  #define PRINTFO(...) PRINTF(__VA_ARGS__)
  #define PRINTPACKETBUF() PRINTF("RIME buffer: "); for(p = 0; p < packetbuf_datalen(); p++){PRINTF("%.2X", *(rime_ptr + p));} PRINTF("\n")
  #define PRINTUIPBUF() PRINTF("UIP buffer: "); for(p = 0; p < uip_len; p++){PRINTF("%.2X", uip_buf[p]);}PRINTF("\n")
  #define PRINTSICSLOWPANBUF() PRINTF("SICSLOWPAN buffer: "); for(p = 0; p < sicslowpan_len; p++){PRINTF("%.2X", sicslowpan_buf[p]);}PRINTF("\n")
  #else
  #define PRINTFI(...)
  #define PRINTFO(...)
  #define PRINTPACKETBUF()
  #define PRINTUIPBUF()
  #define PRINTSICSLOWPANBUF()
  #endif /* DEBUG == 1*/
  
  #if UIP_LOGGING
  #include <stdio.h>
  void uip_log(char *msg);
  #define UIP_LOG(m) uip_log(m)
  #else
  #define UIP_LOG(m)
  #endif /* UIP_LOGGING == 1 */
  
  #ifdef SICSLOWPAN_CONF_MAX_MAC_TRANSMISSIONS
  #define SICSLOWPAN_MAX_MAC_TRANSMISSIONS SICSLOWPAN_CONF_MAX_MAC_TRANSMISSIONS
  #else
  #define SICSLOWPAN_MAX_MAC_TRANSMISSIONS 4
  #endif
  
  #ifndef SICSLOWPAN_COMPRESSION
  #ifdef SICSLOWPAN_CONF_COMPRESSION
  #define SICSLOWPAN_COMPRESSION SICSLOWPAN_CONF_COMPRESSION
  #else
  #define SICSLOWPAN_COMPRESSION SICSLOWPAN_COMPRESSION_IPV6
  #endif /* SICSLOWPAN_CONF_COMPRESSION */
  #endif /* SICSLOWPAN_COMPRESSION */
  
  #define GET16(ptr,index) (((uint16_t)((ptr)[index] << 8)) | ((ptr)[(index) + 1]))
  #define SET16(ptr,index,value) do {     \
    (ptr)[index] = ((value) >> 8) & 0xff; \
    (ptr)[index + 1] = (value) & 0xff;    \
  } while(0)
  
  /** \name Pointers in the rime buffer
   *  @{
   */
  #define RIME_FRAG_PTR           (rime_ptr)
  #define RIME_FRAG_DISPATCH_SIZE 0   /* 16 bit */
  #define RIME_FRAG_TAG           2   /* 16 bit */
  #define RIME_FRAG_OFFSET        4   /* 8 bit */
  
  /* define the buffer as a byte array */
  #define RIME_IPHC_BUF              ((uint8_t *)(rime_ptr + rime_hdr_len))
  
  #define RIME_HC1_PTR            (rime_ptr + rime_hdr_len)
  #define RIME_HC1_DISPATCH       0 /* 8 bit */
  #define RIME_HC1_ENCODING       1 /* 8 bit */
  #define RIME_HC1_TTL            2 /* 8 bit */
  
  #define RIME_HC1_HC_UDP_PTR           (rime_ptr + rime_hdr_len)
  #define RIME_HC1_HC_UDP_DISPATCH      0 /* 8 bit */
  #define RIME_HC1_HC_UDP_HC1_ENCODING  1 /* 8 bit */
  #define RIME_HC1_HC_UDP_UDP_ENCODING  2 /* 8 bit */
  #define RIME_HC1_HC_UDP_TTL           3 /* 8 bit */
  #define RIME_HC1_HC_UDP_PORTS         4 /* 8 bit */
  #define RIME_HC1_HC_UDP_CHKSUM        5 /* 16 bit */
  
  /** \name Pointers in the sicslowpan and uip buffer
   *  @{
   */
  #define SICSLOWPAN_IP_BUF   ((struct uip_ip_hdr *)&sicslowpan_buf[UIP_LLH_LEN])
  #define SICSLOWPAN_UDP_BUF ((struct uip_udp_hdr *)&sicslowpan_buf[UIP_LLIPH_LEN])
  
  #define UIP_IP_BUF          ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
  #define UIP_UDP_BUF          ((struct uip_udp_hdr *)&uip_buf[UIP_LLIPH_LEN])
  #define UIP_TCP_BUF          ((struct uip_tcp_hdr *)&uip_buf[UIP_LLIPH_LEN])
  #define UIP_ICMP_BUF          ((struct uip_icmp_hdr *)&uip_buf[UIP_LLIPH_LEN])
  /** @} */
  
  
  /** \brief Size of the 802.15.4 payload (127byte - 25 for MAC header) */
  #ifdef SICSLOWPAN_CONF_MAC_MAX_PAYLOAD
  #define MAC_MAX_PAYLOAD SICSLOWPAN_CONF_MAC_MAX_PAYLOAD
  #else /* SICSLOWPAN_CONF_MAC_MAX_PAYLOAD */
  #define MAC_MAX_PAYLOAD 102
  #endif /* SICSLOWPAN_CONF_MAC_MAX_PAYLOAD */
  
  
  /** \brief Some MAC layers need a minimum payload, which is
      configurable through the SICSLOWPAN_CONF_MIN_MAC_PAYLOAD
      option. */
  #ifdef SICSLOWPAN_CONF_COMPRESSION_THRESHOLD
  #define COMPRESSION_THRESHOLD SICSLOWPAN_CONF_COMPRESSION_THRESHOLD
  #else
  #define COMPRESSION_THRESHOLD 0
  #endif
  
  /** \name General variables
   *  @{
   */
  #ifdef SICSLOWPAN_NH_COMPRESSOR
  /** A pointer to the additional compressor */
  extern struct sicslowpan_nh_compressor SICSLOWPAN_NH_COMPRESSOR;
  #endif
  
  /**
   * A pointer to the rime buffer.
   * We initialize it to the beginning of the rime buffer, then
   * access different fields by updating the offset rime_hdr_len.
   */
  static uint8_t *rime_ptr;
  
  /**
   * rime_hdr_len is the total length of (the processed) 6lowpan headers
   * (fragment headers, IPV6 or HC1, HC2, and HC1 and HC2 non compressed
   * fields).
   */
  static uint8_t rime_hdr_len;
  
  /**
   * The length of the payload in the Rime buffer.
   * The payload is what comes after the compressed or uncompressed
   * headers (can be the IP payload if the IP header only is compressed
   * or the UDP payload if the UDP header is also compressed)
   */
  static uint8_t rime_payload_len;
  
  /**
   * uncomp_hdr_len is the length of the headers before compression (if HC2
   * is used this includes the UDP header in addition to the IP header).
   */
  static uint8_t uncomp_hdr_len;
  
  /**
   * the result of the last transmitted fragment
   */
  static int last_tx_status;
  /** @} */
  
  #if SICSLOWPAN_CONF_FRAG
  /** \name Fragmentation related variables
   *  @{
   */
  
  static uint16_t sicslowpan_len;
  
  /**
   * The buffer used for the 6lowpan reassembly.
   * This buffer contains only the IPv6 packet (no MAC header, 6lowpan, etc).
   * It has a fix size as we do not use dynamic memory allocation.
   */
  static uip_buf_t sicslowpan_aligned_buf;
  #define sicslowpan_buf (sicslowpan_aligned_buf.u8)
  
  /** The total length of the IPv6 packet in the sicslowpan_buf. */
  
  /**
   * length of the ip packet already sent / received.
   * It includes IP and transport headers.
   */
  static uint16_t processed_ip_in_len;
  
  /** Datagram tag to be put in the fragments I send. */
  static uint16_t my_tag;
  
  /** When reassembling, the tag in the fragments being merged. */
  static uint16_t reass_tag;
  
  /** When reassembling, the source address of the fragments being merged */
  rimeaddr_t frag_sender;
  
  /** Reassembly %process %timer. */
  static struct timer reass_timer;
  
  /** @} */
  #else /* SICSLOWPAN_CONF_FRAG */
  /** The buffer used for the 6lowpan processing is uip_buf.
      We do not use any additional buffer.*/
  #define sicslowpan_buf uip_buf
  #define sicslowpan_len uip_len
  #endif /* SICSLOWPAN_CONF_FRAG */
  
  /*-------------------------------------------------------------------------*/
  /* Rime Sniffer support for one single listener to enable powertrace of IP */
  /*-------------------------------------------------------------------------*/
  static struct rime_sniffer *callback = NULL;
  
  void
  rime_sniffer_add(struct rime_sniffer *s)
  {
    callback = s;
  }
  
  void
  rime_sniffer_remove(struct rime_sniffer *s)
  {
    callback = NULL;
  }
  
  static void
  set_packet_attrs()
  {
    int c = 0;
    /* set protocol in NETWORK_ID */
    packetbuf_set_attr(PACKETBUF_ATTR_NETWORK_ID, UIP_IP_BUF->proto);
  
    /* assign values to the channel attribute (port or type + code) */
    if(UIP_IP_BUF->proto == UIP_PROTO_UDP) {
      c = UIP_UDP_BUF->srcport;
      if(UIP_UDP_BUF->destport < c) {
        c = UIP_UDP_BUF->destport;
      }
    } else if(UIP_IP_BUF->proto == UIP_PROTO_TCP) {
      c = UIP_TCP_BUF->srcport;
      if(UIP_TCP_BUF->destport < c) {
        c = UIP_TCP_BUF->destport;
      }
    } else if(UIP_IP_BUF->proto == UIP_PROTO_ICMP6) {
      c = UIP_ICMP_BUF->type << 8 | UIP_ICMP_BUF->icode;
    }
  
    packetbuf_set_attr(PACKETBUF_ATTR_CHANNEL, c);
  
  /*   if(uip_ds6_is_my_addr(&UIP_IP_BUF->srcipaddr)) { */
  /*     own = 1; */
  /*   } */
  
  }
  
  
  
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06
  /** \name HC06 specific variables
   *  @{
   */
  
  /** Addresses contexts for IPHC. */
  #if SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 0
  static struct sicslowpan_addr_context 
  addr_contexts[SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS];
  #endif
  
  /** pointer to an address context. */
  static struct sicslowpan_addr_context *context;
  
  /** pointer to the byte where to write next inline field. */
  static uint8_t *hc06_ptr;
  
  /* Uncompression of linklocal */
  /*   0 -> 16 bytes from packet  */
  /*   1 -> 2 bytes from prefix - bunch of zeroes and 8 from packet */
  /*   2 -> 2 bytes from prefix - 0000::00ff:fe00:XXXX from packet */
  /*   3 -> 2 bytes from prefix - infer 8 bytes from lladdr */
  /*   NOTE: => the uncompress function does change 0xf to 0x10 */
  /*   NOTE: 0x00 => no-autoconfig => unspecified */
  const uint8_t unc_llconf[] = {0x0f,0x28,0x22,0x20};
  
  /* Uncompression of ctx-based */
  /*   0 -> 0 bits from packet [unspecified / reserved] */
  /*   1 -> 8 bytes from prefix - bunch of zeroes and 8 from packet */
  /*   2 -> 8 bytes from prefix - 0000::00ff:fe00:XXXX + 2 from packet */
  /*   3 -> 8 bytes from prefix - infer 8 bytes from lladdr */
  const uint8_t unc_ctxconf[] = {0x00,0x88,0x82,0x80};
  
  /* Uncompression of ctx-based */
  /*   0 -> 0 bits from packet  */
  /*   1 -> 2 bytes from prefix - bunch of zeroes 5 from packet */
  /*   2 -> 2 bytes from prefix - zeroes + 3 from packet */
  /*   3 -> 2 bytes from prefix - infer 1 bytes from lladdr */
  const uint8_t unc_mxconf[] = {0x0f, 0x25, 0x23, 0x21};
  
  /* Link local prefix */
  const uint8_t llprefix[] = {0xfe, 0x80};
  
  /* TTL uncompression values */
  static const uint8_t ttl_values[] = {0, 1, 64, 255};
  
  /*--------------------------------------------------------------------*/
  /** \name HC06 related functions
   * @{                                                                 */
  /*--------------------------------------------------------------------*/
  /** \brief find the context corresponding to prefix ipaddr */
  static struct sicslowpan_addr_context*
  addr_context_lookup_by_prefix(uip_ipaddr_t *ipaddr)
  {
  /* Remove code to avoid warnings and save flash if no context is used */
  #if SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 0
    int i;
    for(i = 0; i < SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS; i++) {
      if((addr_contexts[i].used == 1) &&
         uip_ipaddr_prefixcmp(&addr_contexts[i].prefix, ipaddr, 64)) {
        return &addr_contexts[i];
      }
    }
  #endif /* SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 0 */
    return NULL;
  }
  /*--------------------------------------------------------------------*/
  /** \brief find the context with the given number */
  static struct sicslowpan_addr_context*
  addr_context_lookup_by_number(uint8_t number)
  {
  /* Remove code to avoid warnings and save flash if no context is used */ 
  #if SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 0
    int i;
    for(i = 0; i < SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS; i++) {
      if((addr_contexts[i].used == 1) &&
         addr_contexts[i].number == number) {
        return &addr_contexts[i];
      }
    }
  #endif /* SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 0 */
    return NULL;
  }
  /*--------------------------------------------------------------------*/
  static uint8_t
  compress_addr_64(uint8_t bitpos, uip_ipaddr_t *ipaddr, uip_lladdr_t *lladdr)
  {
    if(uip_is_addr_mac_addr_based(ipaddr, lladdr)) {
      return 3 << bitpos; /* 0-bits */
    } else if(sicslowpan_is_iid_16_bit_compressable(ipaddr)) {
      /* compress IID to 16 bits xxxx::0000:00ff:fe00:XXXX */
      memcpy(hc06_ptr, &ipaddr->u16[7], 2);
      hc06_ptr += 2;
      return 2 << bitpos; /* 16-bits */
    } else {
      /* do not compress IID => xxxx::IID */
      memcpy(hc06_ptr, &ipaddr->u16[4], 8);
      hc06_ptr += 8;
      return 1 << bitpos; /* 64-bits */
    }
  }
  
  /*-------------------------------------------------------------------- */
  /* Uncompress addresses based on a prefix and a postfix with zeroes in
   * between. If the postfix is zero in length it will use the link address
   * to configure the IP address (autoconf style).
   * pref_post_count takes a byte where the first nibble specify prefix count
   * and the second postfix count (NOTE: 15/0xf => 16 bytes copy).
   */
  static void
  uncompress_addr(uip_ipaddr_t *ipaddr, uint8_t const prefix[],
                  uint8_t pref_post_count, uip_lladdr_t *lladdr)
  {
    uint8_t prefcount = pref_post_count >> 4;
    uint8_t postcount = pref_post_count & 0x0f;
    /* full nibble 15 => 16 */
    prefcount = prefcount == 15 ? 16 : prefcount;
    postcount = postcount == 15 ? 16 : postcount;
  
    PRINTF("Uncompressing %d + %d => ", prefcount, postcount);
  
    if(prefcount > 0) {
      memcpy(ipaddr, prefix, prefcount);
    }
    if(prefcount + postcount < 16) {
      memset(&ipaddr->u8[prefcount], 0, 16 - (prefcount + postcount));
    }
    if(postcount > 0) {
      memcpy(&ipaddr->u8[16 - postcount], hc06_ptr, postcount);
      if(postcount == 2 && prefcount < 11) {
        /* 16 bits uncompression => 0000:00ff:fe00:XXXX */
        ipaddr->u8[11] = 0xff;
        ipaddr->u8[12] = 0xfe;
      }
      hc06_ptr += postcount;
    } else if (prefcount > 0) {
      /* no IID based configuration if no prefix and no data => unspec */
      uip_ds6_set_addr_iid(ipaddr, lladdr);
    }
  
    PRINT6ADDR(ipaddr);
    PRINTF("\n");
  }
  
  /*--------------------------------------------------------------------*/
  /**
   * \brief Compress IP/UDP header
   *
   * This function is called by the 6lowpan code to create a compressed
   * 6lowpan packet in the packetbuf buffer from a full IPv6 packet in the
   * uip_buf buffer.
   *
   *
   * HC-06 (draft-ietf-6lowpan-hc, version 6)\n
   * http://tools.ietf.org/html/draft-ietf-6lowpan-hc-06
   *
   * \note We do not support ISA100_UDP header compression
   *
   * For LOWPAN_UDP compression, we either compress both ports or none.
   * General format with LOWPAN_UDP compression is
   * \verbatim
   *                      1                   2                   3
   *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |0|1|1|TF |N|HLI|C|S|SAM|M|D|DAM| SCI   | DCI   | comp. IPv6 hdr|
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | compressed IPv6 fields .....                                  |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | LOWPAN_UDP    | non compressed UDP fields ...                 |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | L4 data ...                                                   |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * \endverbatim
   * \note The context number 00 is reserved for the link local prefix.
   * For unicast addresses, if we cannot compress the prefix, we neither
   * compress the IID.
   * \param rime_destaddr L2 destination address, needed to compress IP
   * dest
   */
  static void
  compress_hdr_hc06(rimeaddr_t *rime_destaddr)
  {
    uint8_t tmp, iphc0, iphc1;
  #if DEBUG
    { uint16_t ndx;
      PRINTF("before compression (%d): ", UIP_IP_BUF->len[1]);
      for(ndx = 0; ndx < UIP_IP_BUF->len[1] + 40; ndx++) {
        uint8_t data = ((uint8_t *) (UIP_IP_BUF))[ndx];
        PRINTF("%02x", data);
      }
      PRINTF("\n");
    }
  #endif
  
    hc06_ptr = rime_ptr + 2;
    /*
     * As we copy some bit-length fields, in the IPHC encoding bytes,
     * we sometimes use |=
     * If the field is 0, and the current bit value in memory is 1,
     * this does not work. We therefore reset the IPHC encoding here
     */
  
    iphc0 = SICSLOWPAN_DISPATCH_IPHC;
    iphc1 = 0;
    RIME_IPHC_BUF[2] = 0; /* might not be used - but needs to be cleared */
  
    /*
     * Address handling needs to be made first since it might
     * cause an extra byte with [ SCI | DCI ]
     *
     */
  
  
    /* check if dest context exists (for allocating third byte) */
    /* TODO: fix this so that it remembers the looked up values for
       avoiding two lookups - or set the lookup values immediately */
    if(addr_context_lookup_by_prefix(&UIP_IP_BUF->destipaddr) != NULL ||
       addr_context_lookup_by_prefix(&UIP_IP_BUF->srcipaddr) != NULL) {
      /* set context flag and increase hc06_ptr */
      PRINTF("IPHC: compressing dest or src ipaddr - setting CID\n");
      iphc1 |= SICSLOWPAN_IPHC_CID;
      hc06_ptr++;
    }
  
    /*
     * Traffic class, flow label
     * If flow label is 0, compress it. If traffic class is 0, compress it
     * We have to process both in the same time as the offset of traffic class
     * depends on the presence of version and flow label
     */
   
    /* hc06 format of tc is ECN | DSCP , original is DSCP | ECN */
    tmp = (UIP_IP_BUF->vtc << 4) | (UIP_IP_BUF->tcflow >> 4);
    tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
    
    if(((UIP_IP_BUF->tcflow & 0x0F) == 0) &&
       (UIP_IP_BUF->flow == 0)) {
      /* flow label can be compressed */
      iphc0 |= SICSLOWPAN_IPHC_FL_C;
      if(((UIP_IP_BUF->vtc & 0x0F) == 0) &&
         ((UIP_IP_BUF->tcflow & 0xF0) == 0)) {
        /* compress (elide) all */
        iphc0 |= SICSLOWPAN_IPHC_TC_C;
      } else {
        /* compress only the flow label */
       *hc06_ptr = tmp;
        hc06_ptr += 1;
      }
    } else {
      /* Flow label cannot be compressed */
      if(((UIP_IP_BUF->vtc & 0x0F) == 0) &&
         ((UIP_IP_BUF->tcflow & 0xF0) == 0)) {
        /* compress only traffic class */
        iphc0 |= SICSLOWPAN_IPHC_TC_C;
        *hc06_ptr = (tmp & 0xc0) |
          (UIP_IP_BUF->tcflow & 0x0F);
        memcpy(hc06_ptr + 1, &UIP_IP_BUF->flow, 2);
        hc06_ptr += 3;
      } else {
        /* compress nothing */
        memcpy(hc06_ptr, &UIP_IP_BUF->vtc, 4);
        /* but replace the top byte with the new ECN | DSCP format*/
        *hc06_ptr = tmp;
        hc06_ptr += 4;
     }
    }
  
    /* Note that the payload length is always compressed */
  
    /* Next header. We compress it if UDP */
  #if UIP_CONF_UDP || UIP_CONF_ROUTER
    if(UIP_IP_BUF->proto == UIP_PROTO_UDP) {
      iphc0 |= SICSLOWPAN_IPHC_NH_C;
    }
  #endif /*UIP_CONF_UDP*/
  #ifdef SICSLOWPAN_NH_COMPRESSOR 
    if(SICSLOWPAN_NH_COMPRESSOR.is_compressable(UIP_IP_BUF->proto)) {
      iphc0 |= SICSLOWPAN_IPHC_NH_C;
    }
  #endif
    if ((iphc0 & SICSLOWPAN_IPHC_NH_C) == 0) {
      *hc06_ptr = UIP_IP_BUF->proto;
      hc06_ptr += 1;
    }
  
    /*
     * Hop limit
     * if 1: compress, encoding is 01
     * if 64: compress, encoding is 10
     * if 255: compress, encoding is 11
     * else do not compress
     */
    switch(UIP_IP_BUF->ttl) {
      case 1:
        iphc0 |= SICSLOWPAN_IPHC_TTL_1;
        break;
      case 64:
        iphc0 |= SICSLOWPAN_IPHC_TTL_64;
        break;
      case 255:
        iphc0 |= SICSLOWPAN_IPHC_TTL_255;
        break;
      default:
        *hc06_ptr = UIP_IP_BUF->ttl;
        hc06_ptr += 1;
        break;
    }
  
    /* source address - cannot be multicast */
    if(uip_is_addr_unspecified(&UIP_IP_BUF->srcipaddr)) {
      PRINTF("IPHC: compressing unspecified - setting SAC\n");
      iphc1 |= SICSLOWPAN_IPHC_SAC;
      iphc1 |= SICSLOWPAN_IPHC_SAM_00;
    } else if((context = addr_context_lookup_by_prefix(&UIP_IP_BUF->srcipaddr))
       != NULL) {
      /* elide the prefix - indicate by CID and set context + SAC */
      PRINTF("IPHC: compressing src with context - setting CID & SAC ctx: %d\n",
  	   context->number);
      iphc1 |= SICSLOWPAN_IPHC_CID | SICSLOWPAN_IPHC_SAC;
      RIME_IPHC_BUF[2] |= context->number << 4;
      /* compession compare with this nodes address (source) */
  
      iphc1 |= compress_addr_64(SICSLOWPAN_IPHC_SAM_BIT,
                                &UIP_IP_BUF->srcipaddr, &uip_lladdr);
      /* No context found for this address */
    } else if(uip_is_addr_link_local(&UIP_IP_BUF->srcipaddr) &&
  	    UIP_IP_BUF->destipaddr.u16[1] == 0 &&
  	    UIP_IP_BUF->destipaddr.u16[2] == 0 &&
  	    UIP_IP_BUF->destipaddr.u16[3] == 0) {
      iphc1 |= compress_addr_64(SICSLOWPAN_IPHC_SAM_BIT,
                                &UIP_IP_BUF->srcipaddr, &uip_lladdr);
    } else {
      /* send the full address => SAC = 0, SAM = 00 */
      iphc1 |= SICSLOWPAN_IPHC_SAM_00; /* 128-bits */
      memcpy(hc06_ptr, &UIP_IP_BUF->srcipaddr.u16[0], 16);
      hc06_ptr += 16;
    }
  
    /* dest address*/
    if(uip_is_addr_mcast(&UIP_IP_BUF->destipaddr)) {
      /* Address is multicast, try to compress */
      iphc1 |= SICSLOWPAN_IPHC_M;
      if(sicslowpan_is_mcast_addr_compressable8(&UIP_IP_BUF->destipaddr)) {
        iphc1 |= SICSLOWPAN_IPHC_DAM_11;
        /* use last byte */
        *hc06_ptr = UIP_IP_BUF->destipaddr.u8[15];
        hc06_ptr += 1;
      } else if(sicslowpan_is_mcast_addr_compressable32(&UIP_IP_BUF->destipaddr)) {
        iphc1 |= SICSLOWPAN_IPHC_DAM_10;
        /* second byte + the last three */
        *hc06_ptr = UIP_IP_BUF->destipaddr.u8[1];
        memcpy(hc06_ptr + 1, &UIP_IP_BUF->destipaddr.u8[13], 3);
        hc06_ptr += 4;
      } else if(sicslowpan_is_mcast_addr_compressable48(&UIP_IP_BUF->destipaddr)) {
        iphc1 |= SICSLOWPAN_IPHC_DAM_01;
        /* second byte + the last five */
        *hc06_ptr = UIP_IP_BUF->destipaddr.u8[1];
        memcpy(hc06_ptr + 1, &UIP_IP_BUF->destipaddr.u8[11], 5);
        hc06_ptr += 6;
      } else {
        iphc1 |= SICSLOWPAN_IPHC_DAM_00;
        /* full address */
        memcpy(hc06_ptr, &UIP_IP_BUF->destipaddr.u8[0], 16);
        hc06_ptr += 16;
      }
    } else {
      /* Address is unicast, try to compress */
      if((context = addr_context_lookup_by_prefix(&UIP_IP_BUF->destipaddr)) != NULL) {
        /* elide the prefix */
        iphc1 |= SICSLOWPAN_IPHC_DAC;
        RIME_IPHC_BUF[2] |= context->number;
        /* compession compare with link adress (destination) */
  
        iphc1 |= compress_addr_64(SICSLOWPAN_IPHC_DAM_BIT,
  	       &UIP_IP_BUF->destipaddr, (uip_lladdr_t *)rime_destaddr);
        /* No context found for this address */
      } else if(uip_is_addr_link_local(&UIP_IP_BUF->destipaddr) &&
  	      UIP_IP_BUF->destipaddr.u16[1] == 0 &&
  	      UIP_IP_BUF->destipaddr.u16[2] == 0 &&
  	      UIP_IP_BUF->destipaddr.u16[3] == 0) {
        iphc1 |= compress_addr_64(SICSLOWPAN_IPHC_DAM_BIT,
                 &UIP_IP_BUF->destipaddr, (uip_lladdr_t *)rime_destaddr);
      } else {
        /* send the full address */
        iphc1 |= SICSLOWPAN_IPHC_DAM_00; /* 128-bits */
        memcpy(hc06_ptr, &UIP_IP_BUF->destipaddr.u16[0], 16);
        hc06_ptr += 16;
      }
    }
  
    uncomp_hdr_len = UIP_IPH_LEN;
  
  #if UIP_CONF_UDP || UIP_CONF_ROUTER
    /* UDP header compression */
    if(UIP_IP_BUF->proto == UIP_PROTO_UDP) {
      PRINTF("IPHC: Uncompressed UDP ports on send side: %x, %x\n",
  	   UIP_HTONS(UIP_UDP_BUF->srcport), UIP_HTONS(UIP_UDP_BUF->destport));
      /* Mask out the last 4 bits can be used as a mask */
      if(((UIP_HTONS(UIP_UDP_BUF->srcport) & 0xfff0) == SICSLOWPAN_UDP_4_BIT_PORT_MIN) &&
         ((UIP_HTONS(UIP_UDP_BUF->destport) & 0xfff0) == SICSLOWPAN_UDP_4_BIT_PORT_MIN)) {
        /* we can compress 12 bits of both source and dest */
        *hc06_ptr = SICSLOWPAN_NHC_UDP_CS_P_11;
        PRINTF("IPHC: remove 12 b of both source & dest with prefix 0xFOB\n");
        *(hc06_ptr + 1) =
  	(uint8_t)((UIP_HTONS(UIP_UDP_BUF->srcport) -
  		SICSLOWPAN_UDP_4_BIT_PORT_MIN) << 4) +
  	(uint8_t)((UIP_HTONS(UIP_UDP_BUF->destport) -
  		SICSLOWPAN_UDP_4_BIT_PORT_MIN));
        hc06_ptr += 2;
      } else if((UIP_HTONS(UIP_UDP_BUF->destport) & 0xff00) == SICSLOWPAN_UDP_8_BIT_PORT_MIN) {
        /* we can compress 8 bits of dest, leave source. */
        *hc06_ptr = SICSLOWPAN_NHC_UDP_CS_P_01;
        PRINTF("IPHC: leave source, remove 8 bits of dest with prefix 0xF0\n");
        memcpy(hc06_ptr + 1, &UIP_UDP_BUF->srcport, 2);
        *(hc06_ptr + 3) =
  	(uint8_t)((UIP_HTONS(UIP_UDP_BUF->destport) -
  		SICSLOWPAN_UDP_8_BIT_PORT_MIN));
        hc06_ptr += 4;
      } else if((UIP_HTONS(UIP_UDP_BUF->srcport) & 0xff00) == SICSLOWPAN_UDP_8_BIT_PORT_MIN) {
        /* we can compress 8 bits of src, leave dest. Copy compressed port */
        *hc06_ptr = SICSLOWPAN_NHC_UDP_CS_P_10;
        PRINTF("IPHC: remove 8 bits of source with prefix 0xF0, leave dest. hch: %i\n", *hc06_ptr);
        *(hc06_ptr + 1) =
  	(uint8_t)((UIP_HTONS(UIP_UDP_BUF->srcport) -
  		SICSLOWPAN_UDP_8_BIT_PORT_MIN));
        memcpy(hc06_ptr + 2, &UIP_UDP_BUF->destport, 2);
        hc06_ptr += 4;
      } else {
        /* we cannot compress. Copy uncompressed ports, full checksum  */
        *hc06_ptr = SICSLOWPAN_NHC_UDP_CS_P_00;
        PRINTF("IPHC: cannot compress headers\n");
        memcpy(hc06_ptr + 1, &UIP_UDP_BUF->srcport, 4);
        hc06_ptr += 5;
      }
      /* always inline the checksum  */
      if(1) {
        memcpy(hc06_ptr, &UIP_UDP_BUF->udpchksum, 2);
        hc06_ptr += 2;
      }
      uncomp_hdr_len += UIP_UDPH_LEN;
    }
  #endif /*UIP_CONF_UDP*/
  
  #ifdef SICSLOWPAN_NH_COMPRESSOR
    /* if nothing to compress just return zero  */
    hc06_ptr += SICSLOWPAN_NH_COMPRESSOR.compress(hc06_ptr, &uncomp_hdr_len);
  #endif
  
    /* before the rime_hdr_len operation */
    RIME_IPHC_BUF[0] = iphc0;
    RIME_IPHC_BUF[1] = iphc1;
  
    rime_hdr_len = hc06_ptr - rime_ptr;
    return;
  }
  
  /*--------------------------------------------------------------------*/
  /**
   * \brief Uncompress HC06 (i.e., IPHC and LOWPAN_UDP) headers and put
   * them in sicslowpan_buf
   *
   * This function is called by the input function when the dispatch is
   * HC06.
   * We %process the packet in the rime buffer, uncompress the header
   * fields, and copy the result in the sicslowpan buffer.
   * At the end of the decompression, rime_hdr_len and uncompressed_hdr_len
   * are set to the appropriate values
   *
   * \param ip_len Equal to 0 if the packet is not a fragment (IP length
   * is then inferred from the L2 length), non 0 if the packet is a 1st
   * fragment.
   */
  static void
  uncompress_hdr_hc06(uint16_t ip_len)
  {
    uint8_t tmp, iphc0, iphc1;
    /* at least two byte will be used for the encoding */
    hc06_ptr = rime_ptr + rime_hdr_len + 2;
  
    iphc0 = RIME_IPHC_BUF[0];
    iphc1 = RIME_IPHC_BUF[1];
  
    /* another if the CID flag is set */
    if(iphc1 & SICSLOWPAN_IPHC_CID) {
      PRINTF("IPHC: CID flag set - increase header with one\n");
      hc06_ptr++;
    }
  
    /* Traffic class and flow label */
      if((iphc0 & SICSLOWPAN_IPHC_FL_C) == 0) {
        /* Flow label are carried inline */
        if((iphc0 & SICSLOWPAN_IPHC_TC_C) == 0) {
          /* Traffic class is carried inline */
          memcpy(&SICSLOWPAN_IP_BUF->tcflow, hc06_ptr + 1, 3);
          tmp = *hc06_ptr;
          hc06_ptr += 4;
          /* hc06 format of tc is ECN | DSCP , original is DSCP | ECN */
          /* set version, pick highest DSCP bits and set in vtc */
          SICSLOWPAN_IP_BUF->vtc = 0x60 | ((tmp >> 2) & 0x0f);
          /* ECN rolled down two steps + lowest DSCP bits at top two bits */
          SICSLOWPAN_IP_BUF->tcflow = ((tmp >> 2) & 0x30) | (tmp << 6) |
    	(SICSLOWPAN_IP_BUF->tcflow & 0x0f);
        } else {
          /* Traffic class is compressed (set version and no TC)*/
          SICSLOWPAN_IP_BUF->vtc = 0x60;
          /* highest flow label bits + ECN bits */
          SICSLOWPAN_IP_BUF->tcflow = (*hc06_ptr & 0x0F) |
    	((*hc06_ptr >> 2) & 0x30);
          memcpy(&SICSLOWPAN_IP_BUF->flow, hc06_ptr + 1, 2);
          hc06_ptr += 3;
        }
      } else {
        /* Version is always 6! */
        /* Version and flow label are compressed */
        if((iphc0 & SICSLOWPAN_IPHC_TC_C) == 0) {
          /* Traffic class is inline */
            SICSLOWPAN_IP_BUF->vtc = 0x60 | ((*hc06_ptr >> 2) & 0x0f);
            SICSLOWPAN_IP_BUF->tcflow = ((*hc06_ptr << 6) & 0xC0) | ((*hc06_ptr >> 2) & 0x30);
            SICSLOWPAN_IP_BUF->flow = 0;
            hc06_ptr += 1;
        } else {
          /* Traffic class is compressed */
          SICSLOWPAN_IP_BUF->vtc = 0x60;
          SICSLOWPAN_IP_BUF->tcflow = 0;
          SICSLOWPAN_IP_BUF->flow = 0;
        }
      }
  
    /* Next Header */
    if((iphc0 & SICSLOWPAN_IPHC_NH_C) == 0) {
      /* Next header is carried inline */
      SICSLOWPAN_IP_BUF->proto = *hc06_ptr;
      PRINTF("IPHC: next header inline: %d\n", SICSLOWPAN_IP_BUF->proto);
      hc06_ptr += 1;
    }
  
    /* Hop limit */
    if((iphc0 & 0x03) != SICSLOWPAN_IPHC_TTL_I) {
      SICSLOWPAN_IP_BUF->ttl = ttl_values[iphc0 & 0x03];
    } else {
      SICSLOWPAN_IP_BUF->ttl = *hc06_ptr;
      hc06_ptr += 1;
    }
  
    /* put the source address compression mode SAM in the tmp var */
    tmp = ((iphc1 & SICSLOWPAN_IPHC_SAM_11) >> SICSLOWPAN_IPHC_SAM_BIT) & 0x03;
  
    /* context based compression */
    if(iphc1 & SICSLOWPAN_IPHC_SAC) {
      uint8_t sci = (iphc1 & SICSLOWPAN_IPHC_CID) ?
        RIME_IPHC_BUF[2] >> 4 : 0;
  
      /* Source address - check context != NULL only if SAM bits are != 0*/
      if (tmp != 0) {
        context = addr_context_lookup_by_number(sci);
        if(context == NULL) {
          PRINTF("sicslowpan uncompress_hdr: error context not found\n");
          return;
        }
      }
      /* if tmp == 0 we do not have a context and therefore no prefix */
      uncompress_addr(&SICSLOWPAN_IP_BUF->srcipaddr,
                      tmp != 0 ? context->prefix : NULL, unc_ctxconf[tmp],
                      (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER));
    } else {
      /* no compression and link local */
      uncompress_addr(&SICSLOWPAN_IP_BUF->srcipaddr, llprefix, unc_llconf[tmp],
                      (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER));
    }
  
    /* Destination address */
    /* put the destination address compression mode into tmp */
    tmp = ((iphc1 & SICSLOWPAN_IPHC_DAM_11) >> SICSLOWPAN_IPHC_DAM_BIT) & 0x03;
  
    /* multicast compression */
    if(iphc1 & SICSLOWPAN_IPHC_M) {
      /* context based multicast compression */
      if(iphc1 & SICSLOWPAN_IPHC_DAC) {
        /* TODO: implement this */
      } else {
        /* non-context based multicast compression - */
        /* DAM_00: 128 bits  */
        /* DAM_01:  48 bits FFXX::00XX:XXXX:XXXX */
        /* DAM_10:  32 bits FFXX::00XX:XXXX */
        /* DAM_11:   8 bits FF02::00XX */
        uint8_t prefix[] = {0xff, 0x02};
        if(tmp > 0 && tmp < 3) {
          prefix[1] = *hc06_ptr;
          hc06_ptr++;
        }
  
        uncompress_addr(&SICSLOWPAN_IP_BUF->destipaddr, prefix,
                        unc_mxconf[tmp], NULL);
      }
    } else {
      /* no multicast */
      /* Context based */
      if(iphc1 & SICSLOWPAN_IPHC_DAC) {
        uint8_t dci = (iphc1 & SICSLOWPAN_IPHC_CID) ?
  	RIME_IPHC_BUF[2] & 0x0f : 0;
        context = addr_context_lookup_by_number(dci);
  
        /* all valid cases below need the context! */
        if(context == NULL) {
  	PRINTF("sicslowpan uncompress_hdr: error context not found\n");
  	return;
        }
        uncompress_addr(&SICSLOWPAN_IP_BUF->destipaddr, context->prefix,
                        unc_ctxconf[tmp],
                        (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_RECEIVER));
      } else {
        /* not context based => link local M = 0, DAC = 0 - same as SAC */
        uncompress_addr(&SICSLOWPAN_IP_BUF->destipaddr, llprefix,
                        unc_llconf[tmp],
                        (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_RECEIVER));
      }
    }
    uncomp_hdr_len += UIP_IPH_LEN;
  
    /* Next header processing - continued */
    if((iphc0 & SICSLOWPAN_IPHC_NH_C)) {
      /* The next header is compressed, NHC is following */
      if((*hc06_ptr & SICSLOWPAN_NHC_UDP_MASK) == SICSLOWPAN_NHC_UDP_ID) {
        uint8_t checksum_compressed;
        SICSLOWPAN_IP_BUF->proto = UIP_PROTO_UDP;
        checksum_compressed = *hc06_ptr & SICSLOWPAN_NHC_UDP_CHECKSUMC;
        PRINTF("IPHC: Incoming header value: %i\n", *hc06_ptr);
        switch(*hc06_ptr & SICSLOWPAN_NHC_UDP_CS_P_11) {
        case SICSLOWPAN_NHC_UDP_CS_P_00:
  	/* 1 byte for NHC, 4 byte for ports, 2 bytes chksum */
  	memcpy(&SICSLOWPAN_UDP_BUF->srcport, hc06_ptr + 1, 2);
  	memcpy(&SICSLOWPAN_UDP_BUF->destport, hc06_ptr + 3, 2);
  	PRINTF("IPHC: Uncompressed UDP ports (ptr+5): %x, %x\n",
  	       UIP_HTONS(SICSLOWPAN_UDP_BUF->srcport), UIP_HTONS(SICSLOWPAN_UDP_BUF->destport));
  	hc06_ptr += 5;
  	break;
  
        case SICSLOWPAN_NHC_UDP_CS_P_01:
          /* 1 byte for NHC + source 16bit inline, dest = 0xF0 + 8 bit inline */
  	PRINTF("IPHC: Decompressing destination\n");
  	memcpy(&SICSLOWPAN_UDP_BUF->srcport, hc06_ptr + 1, 2);
  	SICSLOWPAN_UDP_BUF->destport = UIP_HTONS(SICSLOWPAN_UDP_8_BIT_PORT_MIN + (*(hc06_ptr + 3)));
  	PRINTF("IPHC: Uncompressed UDP ports (ptr+4): %x, %x\n",
  	       UIP_HTONS(SICSLOWPAN_UDP_BUF->srcport), UIP_HTONS(SICSLOWPAN_UDP_BUF->destport));
  	hc06_ptr += 4;
  	break;
  
        case SICSLOWPAN_NHC_UDP_CS_P_10:
          /* 1 byte for NHC + source = 0xF0 + 8bit inline, dest = 16 bit inline*/
  	PRINTF("IPHC: Decompressing source\n");
  	SICSLOWPAN_UDP_BUF->srcport = UIP_HTONS(SICSLOWPAN_UDP_8_BIT_PORT_MIN +
  					    (*(hc06_ptr + 1)));
  	memcpy(&SICSLOWPAN_UDP_BUF->destport, hc06_ptr + 2, 2);
  	PRINTF("IPHC: Uncompressed UDP ports (ptr+4): %x, %x\n",
  	       UIP_HTONS(SICSLOWPAN_UDP_BUF->srcport), UIP_HTONS(SICSLOWPAN_UDP_BUF->destport));
  	hc06_ptr += 4;
  	break;
  
        case SICSLOWPAN_NHC_UDP_CS_P_11:
  	/* 1 byte for NHC, 1 byte for ports */
  	SICSLOWPAN_UDP_BUF->srcport = UIP_HTONS(SICSLOWPAN_UDP_4_BIT_PORT_MIN +
  					    (*(hc06_ptr + 1) >> 4));
  	SICSLOWPAN_UDP_BUF->destport = UIP_HTONS(SICSLOWPAN_UDP_4_BIT_PORT_MIN +
  					     ((*(hc06_ptr + 1)) & 0x0F));
  	PRINTF("IPHC: Uncompressed UDP ports (ptr+2): %x, %x\n",
  	       UIP_HTONS(SICSLOWPAN_UDP_BUF->srcport), UIP_HTONS(SICSLOWPAN_UDP_BUF->destport));
  	hc06_ptr += 2;
  	break;
  
        default:
  	PRINTF("sicslowpan uncompress_hdr: error unsupported UDP compression\n");
  	return;
        }
        if(!checksum_compressed) { /* has_checksum, default  */
  	memcpy(&SICSLOWPAN_UDP_BUF->udpchksum, hc06_ptr, 2);
  	hc06_ptr += 2;
  	PRINTF("IPHC: sicslowpan uncompress_hdr: checksum included\n");
        } else {
  	PRINTF("IPHC: sicslowpan uncompress_hdr: checksum *NOT* included\n");
        }
        uncomp_hdr_len += UIP_UDPH_LEN;
      }
  #ifdef SICSLOWPAN_NH_COMPRESSOR
      else {
        hc06_ptr += SICSLOWPAN_NH_COMPRESSOR.uncompress(hc06_ptr, sicslowpan_buf, &uncomp_hdr_len);
      }
  #endif
    }
  
    rime_hdr_len = hc06_ptr - rime_ptr;
    
    /* IP length field. */
    if(ip_len == 0) {
      /* This is not a fragmented packet */
      SICSLOWPAN_IP_BUF->len[0] = 0;
      SICSLOWPAN_IP_BUF->len[1] = packetbuf_datalen() - rime_hdr_len + uncomp_hdr_len - UIP_IPH_LEN;
    } else {
      /* This is a 1st fragment */
      SICSLOWPAN_IP_BUF->len[0] = (ip_len - UIP_IPH_LEN) >> 8;
      SICSLOWPAN_IP_BUF->len[1] = (ip_len - UIP_IPH_LEN) & 0x00FF;
    }
    
    /* length field in UDP header */
    if(SICSLOWPAN_IP_BUF->proto == UIP_PROTO_UDP) {
      memcpy(&SICSLOWPAN_UDP_BUF->udplen, &SICSLOWPAN_IP_BUF->len[0], 2);
    }
  
    return;
  }
  /** @} */
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06 */
  
  
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC1
  /*--------------------------------------------------------------------*/
  /** \name HC1 compression and uncompression functions
   *  @{                                                                */
  /*--------------------------------------------------------------------*/
  /**
   * \brief Compress IP/UDP header using HC1 and HC_UDP
   *
   * This function is called by the 6lowpan code to create a compressed
   * 6lowpan packet in the packetbuf buffer from a full IPv6 packet in the
   * uip_buf buffer.
   *
   *
   * If we can compress everything, we use HC1 dispatch, if not we use
   * IPv6 dispatch.\n
   * We can compress everything if:
   *   - IP version is
   *   - Flow label and traffic class are 0
   *   - Both src and dest ip addresses are link local
   *   - Both src and dest interface ID are recoverable from lower layer
   *     header
   *   - Next header is either ICMP, UDP or TCP
   * Moreover, if next header is UDP, we try to compress it using HC_UDP.
   * This is feasible is both ports are between F0B0 and F0B0 + 15\n\n
   *
   * Resulting header structure:
   * - For ICMP, TCP, non compressed UDP\n
   *   HC1 encoding = 11111010 (UDP) 11111110 (TCP) 11111100 (ICMP)\n
   * \verbatim
   *                      1                   2                   3
   * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | LoWPAN HC1 Dsp | HC1 encoding  | IPv6 Hop limit| L4 hdr + data|
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | ...
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * \endverbatim
   *
   * - For compressed UDP
   *   HC1 encoding = 11111011, HC_UDP encoding = 11100000\n
   * \verbatim
   *                      1                   2                   3
   * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | LoWPAN HC1 Dsp| HC1 encoding  |  HC_UDP encod.| IPv6 Hop limit|
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | src p.| dst p.| UDP checksum                  | L4 data...
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * \endverbatim
   *
   * \param rime_destaddr L2 destination address, needed to compress the
   * IP destination field
   */
  static void
  compress_hdr_hc1(rimeaddr_t *rime_destaddr)
  {
    /*
     * Check if all the assumptions for full compression
     * are valid :
     */
    if(UIP_IP_BUF->vtc != 0x60 ||
       UIP_IP_BUF->tcflow != 0 ||
       UIP_IP_BUF->flow != 0 ||
       !uip_is_addr_link_local(&UIP_IP_BUF->srcipaddr) ||
       !uip_is_addr_mac_addr_based(&UIP_IP_BUF->srcipaddr, &uip_lladdr) ||
       !uip_is_addr_link_local(&UIP_IP_BUF->destipaddr) ||
       !uip_is_addr_mac_addr_based(&UIP_IP_BUF->destipaddr,
                                   (uip_lladdr_t *)rime_destaddr) ||
       (UIP_IP_BUF->proto != UIP_PROTO_ICMP6 &&
        UIP_IP_BUF->proto != UIP_PROTO_UDP &&
        UIP_IP_BUF->proto != UIP_PROTO_TCP))
    {
      /*
       * IPV6 DISPATCH
       * Something cannot be compressed, use IPV6 DISPATCH,
       * compress nothing, copy IPv6 header in rime buffer
       */
      *rime_ptr = SICSLOWPAN_DISPATCH_IPV6;
      rime_hdr_len += SICSLOWPAN_IPV6_HDR_LEN;
      memcpy(rime_ptr + rime_hdr_len, UIP_IP_BUF, UIP_IPH_LEN);
      rime_hdr_len += UIP_IPH_LEN;
      uncomp_hdr_len += UIP_IPH_LEN;
    } else {
      /*
       * HC1 DISPATCH
       * maximum compresssion:
       * All fields in the IP header but Hop Limit are elided
       * If next header is UDP, we compress UDP header using HC2
       */
      RIME_HC1_PTR[RIME_HC1_DISPATCH] = SICSLOWPAN_DISPATCH_HC1;
      uncomp_hdr_len += UIP_IPH_LEN;
      switch(UIP_IP_BUF->proto) {
        case UIP_PROTO_ICMP6:
          /* HC1 encoding and ttl */
          RIME_HC1_PTR[RIME_HC1_ENCODING] = 0xFC;
          RIME_HC1_PTR[RIME_HC1_TTL] = UIP_IP_BUF->ttl;
          rime_hdr_len += SICSLOWPAN_HC1_HDR_LEN;
          break;
  #if UIP_CONF_TCP
        case UIP_PROTO_TCP:
          /* HC1 encoding and ttl */
          RIME_HC1_PTR[RIME_HC1_ENCODING] = 0xFE;
          RIME_HC1_PTR[RIME_HC1_TTL] = UIP_IP_BUF->ttl;
          rime_hdr_len += SICSLOWPAN_HC1_HDR_LEN;
          break;
  #endif /* UIP_CONF_TCP */
  #if UIP_CONF_UDP
        case UIP_PROTO_UDP:
          /*
           * try to compress UDP header (we do only full compression).
           * This is feasible if both src and dest ports are between
           * SICSLOWPAN_UDP_PORT_MIN and SICSLOWPAN_UDP_PORT_MIN + 15
           */
          PRINTF("local/remote port %u/%u\n",UIP_UDP_BUF->srcport,UIP_UDP_BUF->destport);
          if(UIP_HTONS(UIP_UDP_BUF->srcport)  >= SICSLOWPAN_UDP_PORT_MIN &&
             UIP_HTONS(UIP_UDP_BUF->srcport)  <  SICSLOWPAN_UDP_PORT_MAX &&
             UIP_HTONS(UIP_UDP_BUF->destport) >= SICSLOWPAN_UDP_PORT_MIN &&
             UIP_HTONS(UIP_UDP_BUF->destport) <  SICSLOWPAN_UDP_PORT_MAX) {
            /* HC1 encoding */
            RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_HC1_ENCODING] = 0xFB;
          
            /* HC_UDP encoding, ttl, src and dest ports, checksum */
            RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_UDP_ENCODING] = 0xE0;
            RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_TTL] = UIP_IP_BUF->ttl;
  
            RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_PORTS] =
                 (uint8_t)((UIP_HTONS(UIP_UDP_BUF->srcport) -
                         SICSLOWPAN_UDP_PORT_MIN) << 4) +
                 (uint8_t)((UIP_HTONS(UIP_UDP_BUF->destport) - SICSLOWPAN_UDP_PORT_MIN));
            memcpy(&RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_CHKSUM], &UIP_UDP_BUF->udpchksum, 2);
            rime_hdr_len += SICSLOWPAN_HC1_HC_UDP_HDR_LEN;
            uncomp_hdr_len += UIP_UDPH_LEN;
          } else {
            /* HC1 encoding and ttl */
            RIME_HC1_PTR[RIME_HC1_ENCODING] = 0xFA;
            RIME_HC1_PTR[RIME_HC1_TTL] = UIP_IP_BUF->ttl;
            rime_hdr_len += SICSLOWPAN_HC1_HDR_LEN;
          }
          break;
  #endif /*UIP_CONF_UDP*/
      }
    }
    return;
  }
  
  /*--------------------------------------------------------------------*/
  /**
   * \brief Uncompress HC1 (and HC_UDP) headers and put them in
   * sicslowpan_buf
   *
   * This function is called by the input function when the dispatch is
   * HC1.
   * We %process the packet in the rime buffer, uncompress the header
   * fields, and copy the result in the sicslowpan buffer.
   * At the end of the decompression, rime_hdr_len and uncompressed_hdr_len
   * are set to the appropriate values
   *
   * \param ip_len Equal to 0 if the packet is not a fragment (IP length
   * is then inferred from the L2 length), non 0 if the packet is a 1st
   * fragment.
   */
  static void
  uncompress_hdr_hc1(uint16_t ip_len)
  {
    /* version, traffic class, flow label */
    SICSLOWPAN_IP_BUF->vtc = 0x60;
    SICSLOWPAN_IP_BUF->tcflow = 0;
    SICSLOWPAN_IP_BUF->flow = 0;
    
    /* src and dest ip addresses */
    uip_ip6addr(&SICSLOWPAN_IP_BUF->srcipaddr, 0xfe80, 0, 0, 0, 0, 0, 0, 0);
    uip_ds6_set_addr_iid(&SICSLOWPAN_IP_BUF->srcipaddr,
  		       (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER));
    uip_ip6addr(&SICSLOWPAN_IP_BUF->destipaddr, 0xfe80, 0, 0, 0, 0, 0, 0, 0);
    uip_ds6_set_addr_iid(&SICSLOWPAN_IP_BUF->destipaddr,
  		       (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_RECEIVER));
    
    uncomp_hdr_len += UIP_IPH_LEN;
    
    /* Next header field */
    switch(RIME_HC1_PTR[RIME_HC1_ENCODING] & 0x06) {
      case SICSLOWPAN_HC1_NH_ICMP6:
        SICSLOWPAN_IP_BUF->proto = UIP_PROTO_ICMP6;
        SICSLOWPAN_IP_BUF->ttl = RIME_HC1_PTR[RIME_HC1_TTL];
        rime_hdr_len += SICSLOWPAN_HC1_HDR_LEN;
        break;
  #if UIP_CONF_TCP
      case SICSLOWPAN_HC1_NH_TCP:
        SICSLOWPAN_IP_BUF->proto = UIP_PROTO_TCP;
        SICSLOWPAN_IP_BUF->ttl = RIME_HC1_PTR[RIME_HC1_TTL];
        rime_hdr_len += SICSLOWPAN_HC1_HDR_LEN;
        break;
  #endif/* UIP_CONF_TCP */
  #if UIP_CONF_UDP
      case SICSLOWPAN_HC1_NH_UDP:
        SICSLOWPAN_IP_BUF->proto = UIP_PROTO_UDP;
        if(RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_HC1_ENCODING] & 0x01) {
          /* UDP header is compressed with HC_UDP */
          if(RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_UDP_ENCODING] !=
             SICSLOWPAN_HC_UDP_ALL_C) {
            PRINTF("sicslowpan (uncompress_hdr), packet not supported");
            return;
          }
          /* IP TTL */
          SICSLOWPAN_IP_BUF->ttl = RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_TTL];
          /* UDP ports, len, checksum */
          SICSLOWPAN_UDP_BUF->srcport =
            UIP_HTONS(SICSLOWPAN_UDP_PORT_MIN +
                  (RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_PORTS] >> 4));
          SICSLOWPAN_UDP_BUF->destport =
            UIP_HTONS(SICSLOWPAN_UDP_PORT_MIN +
                  (RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_PORTS] & 0x0F));
          memcpy(&SICSLOWPAN_UDP_BUF->udpchksum, &RIME_HC1_HC_UDP_PTR[RIME_HC1_HC_UDP_CHKSUM], 2);
          uncomp_hdr_len += UIP_UDPH_LEN;
          rime_hdr_len += SICSLOWPAN_HC1_HC_UDP_HDR_LEN;
        } else {
          rime_hdr_len += SICSLOWPAN_HC1_HDR_LEN;
        }
        break;
  #endif/* UIP_CONF_UDP */
      default:
        /* this shouldn't happen, drop */
        return;
    }
    
    /* IP length field. */
    if(ip_len == 0) {
      /* This is not a fragmented packet */
      SICSLOWPAN_IP_BUF->len[0] = 0;
      SICSLOWPAN_IP_BUF->len[1] = packetbuf_datalen() - rime_hdr_len + uncomp_hdr_len - UIP_IPH_LEN;
    } else {
      /* This is a 1st fragment */
      SICSLOWPAN_IP_BUF->len[0] = (ip_len - UIP_IPH_LEN) >> 8;
      SICSLOWPAN_IP_BUF->len[1] = (ip_len - UIP_IPH_LEN) & 0x00FF;
    }
    /* length field in UDP header */
    if(SICSLOWPAN_IP_BUF->proto == UIP_PROTO_UDP) {
      memcpy(&SICSLOWPAN_UDP_BUF->udplen, &SICSLOWPAN_IP_BUF->len[0], 2);
    }
    return;
  }
  /** @} */
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC1 */
  
  
  
  /*--------------------------------------------------------------------*/
  /** \name IPv6 dispatch "compression" function
   * @{                                                                 */
  /*--------------------------------------------------------------------*/
  /* \brief Packets "Compression" when only IPv6 dispatch is used
   *
   * There is no compression in this case, all fields are sent
   * inline. We just add the IPv6 dispatch byte before the packet.
   * \verbatim
   * 0               1                   2                   3
   * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * | IPv6 Dsp      | IPv6 header and payload ...
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * \endverbatim
   */
  static void
  compress_hdr_ipv6(rimeaddr_t *rime_destaddr)
  {
    *rime_ptr = SICSLOWPAN_DISPATCH_IPV6;
    rime_hdr_len += SICSLOWPAN_IPV6_HDR_LEN;
    memcpy(rime_ptr + rime_hdr_len, UIP_IP_BUF, UIP_IPH_LEN);
    rime_hdr_len += UIP_IPH_LEN;
    uncomp_hdr_len += UIP_IPH_LEN;
    return;
  }
  /** @} */
  
  /*--------------------------------------------------------------------*/
  /** \name Input/output functions common to all compression schemes
   * @{                                                                 */
  /*--------------------------------------------------------------------*/
  /**
   * Callback function for the MAC packet sent callback
   */
  static void
  packet_sent(void *ptr, int status, int transmissions)
  {
    uip_ds6_link_neighbor_callback(status, transmissions);
  
    if(callback != NULL) {
      callback->output_callback(status);
    }
    last_tx_status = status;
  }
  /*--------------------------------------------------------------------*/
  /**
   * \brief This function is called by the 6lowpan code to send out a
   * packet.
   * \param dest the link layer destination address of the packet
   */
  static void
  send_packet(rimeaddr_t *dest)
  {
    /* Set the link layer destination address for the packet as a
     * packetbuf attribute. The MAC layer can access the destination
     * address with the function packetbuf_addr(PACKETBUF_ADDR_RECEIVER).
     */
    packetbuf_set_addr(PACKETBUF_ADDR_RECEIVER, dest);
  
  #if NETSTACK_CONF_BRIDGE_MODE
    /* This needs to be explicitly set here for bridge mode to work */
    packetbuf_set_addr(PACKETBUF_ADDR_SENDER,(void*)&uip_lladdr);
  #endif
  
    /* Force acknowledge from sender (test hardware autoacks) */
  #if SICSLOWPAN_CONF_ACK_ALL
      packetbuf_set_attr(PACKETBUF_ATTR_RELIABLE, 1);
  #endif
  
    /* Provide a callback function to receive the result of
       a packet transmission. */
    NETSTACK_MAC.send(&packet_sent, NULL);
  
    /* If we are sending multiple packets in a row, we need to let the
       watchdog know that we are still alive. */
    watchdog_periodic();
  }
  /*--------------------------------------------------------------------*/
  /** \brief Take an IP packet and format it to be sent on an 802.15.4
   *  network using 6lowpan.
   *  \param localdest The MAC address of the destination
   *
   *  The IP packet is initially in uip_buf. Its header is compressed
   *  and if necessary it is fragmented. The resulting
   *  packet/fragments are put in packetbuf and delivered to the 802.15.4
   *  MAC.
   */
  static uint8_t
  output(uip_lladdr_t *localdest)
  {
    int framer_hdrlen;
  
    /* The MAC address of the destination of the packet */
    rimeaddr_t dest;
  
    /* Number of bytes processed. */
    uint16_t processed_ip_out_len;
  
    /* init */
    uncomp_hdr_len = 0;
    rime_hdr_len = 0;
  
    /* reset rime buffer */
    packetbuf_clear();
    rime_ptr = packetbuf_dataptr();
  
    packetbuf_set_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS,
                       SICSLOWPAN_MAX_MAC_TRANSMISSIONS);
  
    if(callback) {
      /* call the attribution when the callback comes, but set attributes
         here ! */
      set_packet_attrs();
    }
  
  #define TCP_FIN 0x01
  #define TCP_ACK 0x10
  #define TCP_CTL 0x3f
    /* Set stream mode for all TCP packets, except FIN packets. */
    if(UIP_IP_BUF->proto == UIP_PROTO_TCP &&
       (UIP_TCP_BUF->flags & TCP_FIN) == 0 &&
       (UIP_TCP_BUF->flags & TCP_CTL) != TCP_ACK) {
      packetbuf_set_attr(PACKETBUF_ATTR_PACKET_TYPE,
                         PACKETBUF_ATTR_PACKET_TYPE_STREAM);
    } else if(UIP_IP_BUF->proto == UIP_PROTO_TCP &&
              (UIP_TCP_BUF->flags & TCP_FIN) == TCP_FIN) {
      packetbuf_set_attr(PACKETBUF_ATTR_PACKET_TYPE,
                         PACKETBUF_ATTR_PACKET_TYPE_STREAM_END);
    }
  
    /*
     * The destination address will be tagged to each outbound
     * packet. If the argument localdest is NULL, we are sending a
     * broadcast packet.
     */
    if(localdest == NULL) {
      rimeaddr_copy(&dest, &rimeaddr_null);
    } else {
      rimeaddr_copy(&dest, (const rimeaddr_t *)localdest);
    }
    
    PRINTFO("sicslowpan output: sending packet len %d\n", uip_len);
  
    if(uip_len >= COMPRESSION_THRESHOLD) {
      /* Try to compress the headers */
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC1
      compress_hdr_hc1(&dest);
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC1 */
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_IPV6
      compress_hdr_ipv6(&dest);
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_IPV6 */
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06
      compress_hdr_hc06(&dest);
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06 */
    } else {
      compress_hdr_ipv6(&dest);
    }
    PRINTFO("sicslowpan output: header of len %d\n", rime_hdr_len);
  
    /* Calculate NETSTACK_FRAMER's header length, that will be added in the NETSTACK_RDC.
     * We calculate it here only to make a better decision of whether the outgoing packet
     * needs to be fragmented or not. */
  #define USE_FRAMER_HDRLEN 1
  #if USE_FRAMER_HDRLEN
    packetbuf_clear();
    packetbuf_set_addr(PACKETBUF_ADDR_RECEIVER, &dest);
    framer_hdrlen = NETSTACK_FRAMER.create();
    if(framer_hdrlen < 0) {
      /* Framing failed, we assume the maximum header length */
      framer_hdrlen = 21;
    }
    packetbuf_clear();
  
    /* We must set the max transmissions attribute again after clearing
       the buffer. */
    packetbuf_set_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS,
                       SICSLOWPAN_MAX_MAC_TRANSMISSIONS);
  #else /* USE_FRAMER_HDRLEN */
    framer_hdrlen = 21;
  #endif /* USE_FRAMER_HDRLEN */
  
    if((int)uip_len - (int)uncomp_hdr_len > (int)MAC_MAX_PAYLOAD - framer_hdrlen - (int)rime_hdr_len) {
  #if SICSLOWPAN_CONF_FRAG
      struct queuebuf *q;
      /*
       * The outbound IPv6 packet is too large to fit into a single 15.4
       * packet, so we fragment it into multiple packets and send them.
       * The first fragment contains frag1 dispatch, then
       * IPv6/HC1/HC06/HC_UDP dispatchs/headers.
       * The following fragments contain only the fragn dispatch.
       */
  
      PRINTFO("Fragmentation sending packet len %d\n", uip_len);
  
      /* Create 1st Fragment */
      PRINTFO("sicslowpan output: 1rst fragment ");
  
      /* move HC1/HC06/IPv6 header */
      memmove(rime_ptr + SICSLOWPAN_FRAG1_HDR_LEN, rime_ptr, rime_hdr_len);
  
      /*
       * FRAG1 dispatch + header
       * Note that the length is in units of 8 bytes
       */
  /*     RIME_FRAG_BUF->dispatch_size = */
  /*       uip_htons((SICSLOWPAN_DISPATCH_FRAG1 << 8) | uip_len); */
      SET16(RIME_FRAG_PTR, RIME_FRAG_DISPATCH_SIZE,
            ((SICSLOWPAN_DISPATCH_FRAG1 << 8) | uip_len));
  /*     RIME_FRAG_BUF->tag = uip_htons(my_tag); */
      SET16(RIME_FRAG_PTR, RIME_FRAG_TAG, my_tag);
      my_tag++;
  
      /* Copy payload and send */
      rime_hdr_len += SICSLOWPAN_FRAG1_HDR_LEN;
      rime_payload_len = (MAC_MAX_PAYLOAD - framer_hdrlen - rime_hdr_len) & 0xf8;
      PRINTFO("(len %d, tag %d)\n", rime_payload_len, my_tag);
      memcpy(rime_ptr + rime_hdr_len,
             (uint8_t *)UIP_IP_BUF + uncomp_hdr_len, rime_payload_len);
      packetbuf_set_datalen(rime_payload_len + rime_hdr_len);
      q = queuebuf_new_from_packetbuf();
      if(q == NULL) {
        PRINTFO("could not allocate queuebuf for first fragment, dropping packet\n");
        return 0;
      }
      send_packet(&dest);
      queuebuf_to_packetbuf(q);
      queuebuf_free(q);
      q = NULL;
  
      /* Check tx result. */
      if((last_tx_status == MAC_TX_COLLISION) ||
         (last_tx_status == MAC_TX_ERR) ||
         (last_tx_status == MAC_TX_ERR_FATAL)) {
        PRINTFO("error in fragment tx, dropping subsequent fragments.\n");
        return 0;
      }
  
      /* set processed_ip_out_len to what we already sent from the IP payload*/
      processed_ip_out_len = rime_payload_len + uncomp_hdr_len;
      
      /*
       * Create following fragments
       * Datagram tag is already in the buffer, we need to set the
       * FRAGN dispatch and for each fragment, the offset
       */
      rime_hdr_len = SICSLOWPAN_FRAGN_HDR_LEN;
  /*     RIME_FRAG_BUF->dispatch_size = */
  /*       uip_htons((SICSLOWPAN_DISPATCH_FRAGN << 8) | uip_len); */
      SET16(RIME_FRAG_PTR, RIME_FRAG_DISPATCH_SIZE,
            ((SICSLOWPAN_DISPATCH_FRAGN << 8) | uip_len));
      rime_payload_len = (MAC_MAX_PAYLOAD - framer_hdrlen - rime_hdr_len) & 0xf8;
      while(processed_ip_out_len < uip_len) {
        PRINTFO("sicslowpan output: fragment ");
        RIME_FRAG_PTR[RIME_FRAG_OFFSET] = processed_ip_out_len >> 3;
        
        /* Copy payload and send */
        if(uip_len - processed_ip_out_len < rime_payload_len) {
          /* last fragment */
          rime_payload_len = uip_len - processed_ip_out_len;
        }
        PRINTFO("(offset %d, len %d, tag %d)\n",
               processed_ip_out_len >> 3, rime_payload_len, my_tag);
        memcpy(rime_ptr + rime_hdr_len,
               (uint8_t *)UIP_IP_BUF + processed_ip_out_len, rime_payload_len);
        packetbuf_set_datalen(rime_payload_len + rime_hdr_len);
        q = queuebuf_new_from_packetbuf();
        if(q == NULL) {
          PRINTFO("could not allocate queuebuf, dropping fragment\n");
          return 0;
        }
        send_packet(&dest);
        queuebuf_to_packetbuf(q);
        queuebuf_free(q);
        q = NULL;
        processed_ip_out_len += rime_payload_len;
  
        /* Check tx result. */
        if((last_tx_status == MAC_TX_COLLISION) ||
           (last_tx_status == MAC_TX_ERR) ||
           (last_tx_status == MAC_TX_ERR_FATAL)) {
          PRINTFO("error in fragment tx, dropping subsequent fragments.\n");
          return 0;
        }
      }
  #else /* SICSLOWPAN_CONF_FRAG */
      PRINTFO("sicslowpan output: Packet too large to be sent without fragmentation support; dropping packet\n");
      return 0;
  #endif /* SICSLOWPAN_CONF_FRAG */
    } else {
  
      /*
       * The packet does not need to be fragmented
       * copy "payload" and send
       */
      memcpy(rime_ptr + rime_hdr_len, (uint8_t *)UIP_IP_BUF + uncomp_hdr_len,
             uip_len - uncomp_hdr_len);
      packetbuf_set_datalen(uip_len - uncomp_hdr_len + rime_hdr_len);
      send_packet(&dest);
    }
    return 1;
  }
  
  /*--------------------------------------------------------------------*/
  /** \brief Process a received 6lowpan packet.
   *  \param r The MAC layer
   *
   *  The 6lowpan packet is put in packetbuf by the MAC. If its a frag1 or
   *  a non-fragmented packet we first uncompress the IP header. The
   *  6lowpan payload and possibly the uncompressed IP header are then
   *  copied in siclowpan_buf. If the IP packet is complete it is copied
   *  to uip_buf and the IP layer is called.
   *
   * \note We do not check for overlapping sicslowpan fragments
   * (it is a SHALL in the RFC 4944 and should never happen)
   */
  static void
  input(void)
  {
    /* size of the IP packet (read from fragment) */
    uint16_t frag_size = 0;
    /* offset of the fragment in the IP packet */
    uint8_t frag_offset = 0;
    uint8_t is_fragment = 0;
  #if SICSLOWPAN_CONF_FRAG
    /* tag of the fragment */
    uint16_t frag_tag = 0;
    uint8_t first_fragment = 0, last_fragment = 0;
  #endif /*SICSLOWPAN_CONF_FRAG*/
  
    /* init */
    uncomp_hdr_len = 0;
    rime_hdr_len = 0;
  
    /* The MAC puts the 15.4 payload inside the RIME data buffer */
    rime_ptr = packetbuf_dataptr();
  
  #if SICSLOWPAN_CONF_FRAG
    /* if reassembly timed out, cancel it */
    if(timer_expired(&reass_timer)) {
      sicslowpan_len = 0;
      processed_ip_in_len = 0;
    }
    /*
     * Since we don't support the mesh and broadcast header, the first header
     * we look for is the fragmentation header
     */
    switch((GET16(RIME_FRAG_PTR, RIME_FRAG_DISPATCH_SIZE) & 0xf800) >> 8) {
      case SICSLOWPAN_DISPATCH_FRAG1:
        PRINTFI("sicslowpan input: FRAG1 ");
        frag_offset = 0;
  /*       frag_size = (uip_ntohs(RIME_FRAG_BUF->dispatch_size) & 0x07ff); */
        frag_size = GET16(RIME_FRAG_PTR, RIME_FRAG_DISPATCH_SIZE) & 0x07ff;
  /*       frag_tag = uip_ntohs(RIME_FRAG_BUF->tag); */
        frag_tag = GET16(RIME_FRAG_PTR, RIME_FRAG_TAG);
        PRINTFI("size %d, tag %d, offset %d)\n",
               frag_size, frag_tag, frag_offset);
        rime_hdr_len += SICSLOWPAN_FRAG1_HDR_LEN;
        /*      printf("frag1 %d %d\n", reass_tag, frag_tag);*/
        first_fragment = 1;
        is_fragment = 1;
        break;
      case SICSLOWPAN_DISPATCH_FRAGN:
        /*
         * set offset, tag, size
         * Offset is in units of 8 bytes
         */
        PRINTFI("sicslowpan input: FRAGN ");
        frag_offset = RIME_FRAG_PTR[RIME_FRAG_OFFSET];
        frag_tag = GET16(RIME_FRAG_PTR, RIME_FRAG_TAG);
        frag_size = GET16(RIME_FRAG_PTR, RIME_FRAG_DISPATCH_SIZE) & 0x07ff;
        PRINTFI("size %d, tag %d, offset %d)\n",
               frag_size, frag_tag, frag_offset);
        rime_hdr_len += SICSLOWPAN_FRAGN_HDR_LEN;
  
        /* If this is the last fragment, we may shave off any extrenous
           bytes at the end. We must be liberal in what we accept. */
        PRINTFI("last_fragment?: processed_ip_in_len %d rime_payload_len %d frag_size %d\n",
                processed_ip_in_len, packetbuf_datalen() - rime_hdr_len, frag_size);
  
        if(processed_ip_in_len + packetbuf_datalen() - rime_hdr_len >= frag_size) {
          last_fragment = 1;
        }
        is_fragment = 1;
        break;
      default:
        break;
    }
  
    /* We are currently reassembling a packet, but have just received the first
     * fragment of another packet. We can either ignore it and hope to receive
     * the rest of the under-reassembly packet fragments, or we can discard the
     * previous packet altogether, and start reassembling the new packet.
     *
     * We discard the previous packet, and start reassembling the new packet.
     * This lessens the negative impacts of too high SICSLOWPAN_REASS_MAXAGE.
     */
  #define PRIORITIZE_NEW_PACKETS 1
  #if PRIORITIZE_NEW_PACKETS
    if(processed_ip_in_len > 0 && first_fragment
        && !rimeaddr_cmp(&frag_sender, packetbuf_addr(PACKETBUF_ADDR_SENDER))) {
      sicslowpan_len = 0;
      processed_ip_in_len = 0;
    }
  #endif /* PRIORITIZE_NEW_PACKETS */
  
    if(processed_ip_in_len > 0) {
      /* reassembly is ongoing */
      /*    printf("frag %d %d\n", reass_tag, frag_tag);*/
      if((frag_size > 0 &&
          (frag_size != sicslowpan_len ||
           reass_tag  != frag_tag ||
           !rimeaddr_cmp(&frag_sender, packetbuf_addr(PACKETBUF_ADDR_SENDER))))  ||
         frag_size == 0) {
        /*
         * the packet is a fragment that does not belong to the packet
         * being reassembled or the packet is not a fragment.
         */
        PRINTFI("sicslowpan input: Dropping 6lowpan packet that is not a fragment of the packet currently being reassembled\n");
        return;
      }
    } else {
      /*
       * reassembly is off
       * start it if we received a fragment
       */
      if((frag_size > 0) && (frag_size <= UIP_BUFSIZE)) {
        /* We are currently not reassembling a packet, but have received a packet fragment
         * that is not the first one. */
        if(is_fragment && !first_fragment) {
          return;
        }
  
        sicslowpan_len = frag_size;
        reass_tag = frag_tag;
        timer_set(&reass_timer, SICSLOWPAN_REASS_MAXAGE * CLOCK_SECOND / 16);
        PRINTFI("sicslowpan input: INIT FRAGMENTATION (len %d, tag %d)\n",
               sicslowpan_len, reass_tag);
        rimeaddr_copy(&frag_sender, packetbuf_addr(PACKETBUF_ADDR_SENDER));
      }
    }
  
    if(rime_hdr_len == SICSLOWPAN_FRAGN_HDR_LEN) {
      /* this is a FRAGN, skip the header compression dispatch section */
      goto copypayload;
    }
  #endif /* SICSLOWPAN_CONF_FRAG */
  
    /* Process next dispatch and headers */
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06
    if((RIME_HC1_PTR[RIME_HC1_DISPATCH] & 0xe0) == SICSLOWPAN_DISPATCH_IPHC) {
      PRINTFI("sicslowpan input: IPHC\n");
      uncompress_hdr_hc06(frag_size);
    } else
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06 */
      switch(RIME_HC1_PTR[RIME_HC1_DISPATCH]) {
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC1
      case SICSLOWPAN_DISPATCH_HC1:
        PRINTFI("sicslowpan input: HC1\n");
        uncompress_hdr_hc1(frag_size);
        break;
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC1 */
      case SICSLOWPAN_DISPATCH_IPV6:
        PRINTFI("sicslowpan input: IPV6\n");
        rime_hdr_len += SICSLOWPAN_IPV6_HDR_LEN;
  
        /* Put uncompressed IP header in sicslowpan_buf. */
        memcpy(SICSLOWPAN_IP_BUF, rime_ptr + rime_hdr_len, UIP_IPH_LEN);
  
        /* Update uncomp_hdr_len and rime_hdr_len. */
        rime_hdr_len += UIP_IPH_LEN;
        uncomp_hdr_len += UIP_IPH_LEN;
        break;
      default:
        /* unknown header */
        PRINTFI("sicslowpan input: unknown dispatch: %u\n",
               RIME_HC1_PTR[RIME_HC1_DISPATCH]);
        return;
    }
     
      
  #if SICSLOWPAN_CONF_FRAG
   copypayload:
  #endif /*SICSLOWPAN_CONF_FRAG*/
    /*
     * copy "payload" from the rime buffer to the sicslowpan_buf
     * if this is a first fragment or not fragmented packet,
     * we have already copied the compressed headers, uncomp_hdr_len
     * and rime_hdr_len are non 0, frag_offset is.
     * If this is a subsequent fragment, this is the contrary.
     */
    if(packetbuf_datalen() < rime_hdr_len) {
      PRINTF("SICSLOWPAN: packet dropped due to header > total packet\n");
      return;
    }
    rime_payload_len = packetbuf_datalen() - rime_hdr_len;
  
    /* Sanity-check size of incoming packet to avoid buffer overflow */
    {
      int req_size = UIP_LLH_LEN + uncomp_hdr_len + (uint16_t)(frag_offset << 3)
          + rime_payload_len;
      if(req_size > sizeof(sicslowpan_buf)) {
        PRINTF(
            "SICSLOWPAN: packet dropped, minimum required SICSLOWPAN_IP_BUF size: %d+%d+%d+%d=%d (current size: %d)\n",
            UIP_LLH_LEN, uncomp_hdr_len, (uint16_t)(frag_offset << 3),
            rime_payload_len, req_size, sizeof(sicslowpan_buf));
        return;
      }
    }
  
    memcpy((uint8_t *)SICSLOWPAN_IP_BUF + uncomp_hdr_len + (uint16_t)(frag_offset << 3), rime_ptr + rime_hdr_len, rime_payload_len);
    
    /* update processed_ip_in_len if fragment, sicslowpan_len otherwise */
  
  #if SICSLOWPAN_CONF_FRAG
    if(frag_size > 0) {
      /* Add the size of the header only for the first fragment. */
      if(first_fragment != 0) {
        processed_ip_in_len += uncomp_hdr_len;
      }
      /* For the last fragment, we are OK if there is extrenous bytes at
         the end of the packet. */
      if(last_fragment != 0) {
        processed_ip_in_len = frag_size;
      } else {
        processed_ip_in_len += rime_payload_len;
      }
      PRINTF("processed_ip_in_len %d, rime_payload_len %d\n", processed_ip_in_len, rime_payload_len);
  
    } else {
  #endif /* SICSLOWPAN_CONF_FRAG */
      sicslowpan_len = rime_payload_len + uncomp_hdr_len;
  #if SICSLOWPAN_CONF_FRAG
    }
  
    /*
     * If we have a full IP packet in sicslowpan_buf, deliver it to
     * the IP stack
     */
    PRINTF("sicslowpan_init processed_ip_in_len %d, sicslowpan_len %d\n",
           processed_ip_in_len, sicslowpan_len);
    if(processed_ip_in_len == 0 || (processed_ip_in_len == sicslowpan_len)) {
      PRINTFI("sicslowpan input: IP packet ready (length %d)\n",
             sicslowpan_len);
      memcpy((uint8_t *)UIP_IP_BUF, (uint8_t *)SICSLOWPAN_IP_BUF, sicslowpan_len);
      uip_len = sicslowpan_len;
      sicslowpan_len = 0;
      processed_ip_in_len = 0;
  #endif /* SICSLOWPAN_CONF_FRAG */
  
  #if DEBUG
      {
        uint16_t ndx;
        PRINTF("after decompression %u:", SICSLOWPAN_IP_BUF->len[1]);
        for (ndx = 0; ndx < SICSLOWPAN_IP_BUF->len[1] + 40; ndx++) {
          uint8_t data = ((uint8_t *) (SICSLOWPAN_IP_BUF))[ndx];
          PRINTF("%02x", data);
        }
        PRINTF("\n");
      }
  #endif
  
      /* if callback is set then set attributes and call */
      if(callback) {
        set_packet_attrs();
        callback->input_callback();
      }
  
      tcpip_input();
  #if SICSLOWPAN_CONF_FRAG
    }
  #endif /* SICSLOWPAN_CONF_FRAG */
  }
  /** @} */
  
  /*--------------------------------------------------------------------*/
  /* \brief 6lowpan init function (called by the MAC layer)             */
  /*--------------------------------------------------------------------*/
  void
  sicslowpan_init(void)
  {
    /*
     * Set out output function as the function to be called from uIP to
     * send a packet.
     */
    tcpip_set_outputfunc(output);
  
  #if SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06
  /* Preinitialize any address contexts for better header compression
   * (Saves up to 13 bytes per 6lowpan packet)
   * The platform contiki-conf.h file can override this using e.g.
   * #define SICSLOWPAN_CONF_ADDR_CONTEXT_0 {addr_contexts[0].prefix[0]=0xbb;addr_contexts[0].prefix[1]=0xbb;}
   */
  #if SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 0 
    addr_contexts[0].used   = 1;
    addr_contexts[0].number = 0;
  #ifdef SICSLOWPAN_CONF_ADDR_CONTEXT_0
  	SICSLOWPAN_CONF_ADDR_CONTEXT_0;
  #else
    addr_contexts[0].prefix[0] = 0xaa; 
    addr_contexts[0].prefix[1] = 0xaa;
  #endif
  #endif /* SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 0 */
  
  #if SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 1
    {
      int i;
      for(i = 1; i < SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS; i++) {
  #ifdef SICSLOWPAN_CONF_ADDR_CONTEXT_1
  	  if (i==1) {
  	    addr_contexts[1].used   = 1;
  		addr_contexts[1].number = 1;
  		SICSLOWPAN_CONF_ADDR_CONTEXT_1;
  #ifdef SICSLOWPAN_CONF_ADDR_CONTEXT_2
        } else if (i==2) {
  	  	addr_contexts[2].used   = 1;
  		addr_contexts[2].number = 2;
  		SICSLOWPAN_CONF_ADDR_CONTEXT_2;
  #endif
        } else {
          addr_contexts[i].used = 0;
        }	  
  #else
        addr_contexts[i].used = 0;
  #endif /* SICSLOWPAN_CONF_ADDR_CONTEXT_1 */
  
      }
    }
  #endif /* SICSLOWPAN_CONF_MAX_ADDR_CONTEXTS > 1 */
  
  #endif /* SICSLOWPAN_COMPRESSION == SICSLOWPAN_COMPRESSION_HC06 */
  }
  /*--------------------------------------------------------------------*/
  const struct network_driver sicslowpan_driver = {
    "sicslowpan",
    sicslowpan_init,
    input
  };
  /*--------------------------------------------------------------------*/
  /** @} */
  #endif /* UIP_CONF_IPV6 */
  