lowpan6_ble.c

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/*
 * Copyright (c) 2017 Benjamin Aigner
 * Copyright (c) 2015 Inico Technologies Ltd. , Author: Ivan Delamer <delamer@inicotech.com>
 *
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * Author: Benjamin Aigner <aignerb@technikum-wien.at>
 *
 * Based on the original 6lowpan implementation of lwIP ( @see 6lowpan.c)
 */
 
 
#include "netif/lowpan6_ble.h"
 
#if LWIP_IPV6
 
#include "lwip/ip.h"
#include "lwip/pbuf.h"
#include "lwip/ip_addr.h"
#include "lwip/netif.h"
#include "lwip/nd6.h"
#include "lwip/mem.h"
#include "lwip/udp.h"
#include "lwip/tcpip.h"
#include "lwip/snmp.h"
 
#include <string.h>
 
#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
static ip6_addr_t rfc7668_context[LWIP_6LOWPAN_NUM_CONTEXTS];
#else
#define rfc7668_context NULL
#endif
 
static struct lowpan6_link_addr rfc7668_local_addr;
static struct lowpan6_link_addr rfc7668_peer_addr;
 
void
ble_addr_to_eui64(u8_t *dst, const u8_t *src, int public_addr)
{
  /* according to RFC7668 ch 3.2.2. */
  memcpy(dst, src, 3);
  dst[3] = 0xFF;
  dst[4] = 0xFE;
  memcpy(&dst[5], &src[3], 3);
#if LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS
  if(public_addr) {
    dst[0] &= ~0x02;
  } else {
    dst[0] |= 0x02;
  }
#else
  LWIP_UNUSED_ARG(public_addr);
#endif
}
 
void
eui64_to_ble_addr(u8_t *dst, const u8_t *src)
{
  /* according to RFC7668 ch 3.2.2. */
  memcpy(dst,src,3);
  memcpy(&dst[3],&src[5],3);
}
 
static err_t
rfc7668_set_addr(struct lowpan6_link_addr *addr, const u8_t *in_addr, size_t in_addr_len, int is_mac_48, int is_public_addr)
{
  if ((in_addr == NULL) || (addr == NULL)) {
    return ERR_VAL;
  }
  if (is_mac_48) {
    if (in_addr_len != 6) {
      return ERR_VAL;
    }
    addr->addr_len = 8;
    ble_addr_to_eui64(addr->addr, in_addr, is_public_addr);
  } else {
    if (in_addr_len != 8) {
      return ERR_VAL;
    }
    addr->addr_len = 8;
    memcpy(addr->addr, in_addr, 8);
  }
  return ERR_OK;
}
 
 
err_t
rfc7668_set_local_addr_eui64(struct netif *netif, const u8_t *local_addr, size_t local_addr_len)
{
  /* netif not used for now, the address is stored globally... */
  LWIP_UNUSED_ARG(netif);
  return rfc7668_set_addr(&rfc7668_local_addr, local_addr, local_addr_len, 0, 0);
}
 
err_t
rfc7668_set_local_addr_mac48(struct netif *netif, const u8_t *local_addr, size_t local_addr_len, int is_public_addr)
{
  /* netif not used for now, the address is stored globally... */
  LWIP_UNUSED_ARG(netif);
  return rfc7668_set_addr(&rfc7668_local_addr, local_addr, local_addr_len, 1, is_public_addr);
}
 
err_t
rfc7668_set_peer_addr_eui64(struct netif *netif, const u8_t *peer_addr, size_t peer_addr_len)
{
  /* netif not used for now, the address is stored globally... */
  LWIP_UNUSED_ARG(netif);
  return rfc7668_set_addr(&rfc7668_peer_addr, peer_addr, peer_addr_len, 0, 0);
}
 
err_t
rfc7668_set_peer_addr_mac48(struct netif *netif, const u8_t *peer_addr, size_t peer_addr_len, int is_public_addr)
{
  /* netif not used for now, the address is stored globally... */
  LWIP_UNUSED_ARG(netif);
  return rfc7668_set_addr(&rfc7668_peer_addr, peer_addr, peer_addr_len, 1, is_public_addr);
}
 
static err_t
rfc7668_compress(struct netif *netif, struct pbuf *p)
{
  struct pbuf *p_frag;
  u16_t remaining_len;
  u8_t *buffer;
  u8_t lowpan6_header_len;
  u8_t hidden_header_len;
  err_t err;
 
  LWIP_ASSERT("lowpan6_frag: netif->linkoutput not set", netif->linkoutput != NULL);
 
#if LWIP_6LOWPAN_IPHC
 
  /* We'll use a dedicated pbuf for building BLE fragments.
   * We'll over-allocate it by the bytes saved for header compression.
   */
  p_frag = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
  if (p_frag == NULL) {
    MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
    return ERR_MEM;
  }
  LWIP_ASSERT("this needs a pbuf in one piece", p_frag->len == p_frag->tot_len);
 
  /* Write IP6 header (with IPHC). */
  buffer = (u8_t*)p_frag->payload;
 
  err = lowpan6_compress_headers(netif, (u8_t *)p->payload, p->len, buffer, p_frag->len,
    &lowpan6_header_len, &hidden_header_len, rfc7668_context, &rfc7668_local_addr, &rfc7668_peer_addr);
  if (err != ERR_OK) {
    MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
    pbuf_free(p_frag);
    return err;
  }
  pbuf_remove_header(p, hidden_header_len);
 
  /* Calculate remaining packet length */
  remaining_len = p->tot_len;
 
  /* Copy IPv6 packet */
  pbuf_copy_partial(p, buffer + lowpan6_header_len, remaining_len, 0);
 
  /* Calculate frame length */
  p_frag->len = p_frag->tot_len = remaining_len + lowpan6_header_len;
 
  /* send the packet */
  MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
  LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG|LWIP_DBG_TRACE, ("rfc7668_output: sending packet %p\n", (void *)p));
  err = netif->linkoutput(netif, p_frag);
 
  pbuf_free(p_frag);
 
  return err;
#else /* LWIP_6LOWPAN_IPHC */
  /* 6LoWPAN over BLE requires IPHC! */
  return ERR_IF;
#endif/* LWIP_6LOWPAN_IPHC */
}
 
err_t
rfc7668_set_context(u8_t idx, const ip6_addr_t *context)
{
#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
  /* check if the ID is possible */
  if (idx >= LWIP_6LOWPAN_NUM_CONTEXTS) {
    return ERR_ARG;
  }
  /* copy IPv6 address to context storage */
  ip6_addr_set(&rfc7668_context[idx], context);
  return ERR_OK;
#else
  LWIP_UNUSED_ARG(idx);
  LWIP_UNUSED_ARG(context);
  return ERR_VAL;
#endif
}
 
err_t
rfc7668_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
{
  /* dst ip6addr is not used here, we only have one peer */
  LWIP_UNUSED_ARG(ip6addr);
 
  return rfc7668_compress(netif, q);
}
 
err_t
rfc7668_input(struct pbuf * p, struct netif *netif)
{
  u8_t * puc;
 
  MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
 
  /* Load first header byte */
  puc = (u8_t*)p->payload;
 
  /* no IP header compression */
  if (*puc == 0x41) {
    LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, removing dispatch: 0x%2x \n", *puc));
    /* This is a complete IPv6 packet, just skip header byte. */
    pbuf_remove_header(p, 1);
  /* IPHC header compression */
  } else if ((*puc & 0xe0 )== 0x60) {
    LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, decompress dispatch: 0x%2x \n", *puc));
    /* IPv6 headers are compressed using IPHC. */
    p = lowpan6_decompress(p, 0, rfc7668_context, &rfc7668_peer_addr, &rfc7668_local_addr);
    /* if no pbuf is returned, handle as discarded packet */
    if (p == NULL) {
      MIB2_STATS_NETIF_INC(netif, ifindiscards);
      return ERR_OK;
    }
  /* invalid header byte, discard */
  } else {
    LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, discarding: 0x%2x \n", *puc));
    MIB2_STATS_NETIF_INC(netif, ifindiscards);
    pbuf_free(p);
    return ERR_OK;
  }
  /* @todo: distinguish unicast/multicast */
  MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
 
#if LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG
  {
    u16_t i;
    LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("IPv6 payload:\n"));
    for (i = 0; i < p->len; i++) {
      if ((i%4)==0) {
        LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("\n"));
      }
      LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("%2X ", *((u8_t *)p->payload+i)));
    }
    LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("\np->len: %d\n", p->len));
  }
#endif
  /* pass data to ip6_input */
  return ip6_input(p, netif);
}
 
err_t
rfc7668_if_init(struct netif *netif)
{
  netif->name[0] = 'b';
  netif->name[1] = 't';
  /* local function as IPv6 output */
  netif->output_ip6 = rfc7668_output;
 
  MIB2_INIT_NETIF(netif, snmp_ifType_other, 0);
 
  /* maximum transfer unit, set according to RFC7668 ch2.4 */
  netif->mtu = IP6_MIN_MTU_LENGTH;
 
  /* no flags set (no broadcast, ethernet,...)*/
  netif->flags = 0;
 
  /* everything fine */
  return ERR_OK;
}
 
#if !NO_SYS
err_t
tcpip_rfc7668_input(struct pbuf *p, struct netif *inp)
{
  /* send data to upper layer, return the result */
  return tcpip_inpkt(p, inp, rfc7668_input);
}
#endif /* !NO_SYS */
 
#endif /* LWIP_IPV6 */