448 lines
13 KiB
C
448 lines
13 KiB
C
/**
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* @file
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* 6LowPAN over BLE output for IPv6 (RFC7668).
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*/
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/*
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* Copyright (c) 2017 Benjamin Aigner
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* Copyright (c) 2015 Inico Technologies Ltd. , Author: Ivan Delamer <delamer@inicotech.com>
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* Author: Benjamin Aigner <aignerb@technikum-wien.at>
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*
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* Based on the original 6lowpan implementation of lwIP ( @see 6lowpan.c)
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*/
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/**
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* @defgroup rfc7668if 6LoWPAN over BLE (RFC7668)
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* @ingroup netifs
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* This file implements a RFC7668 implementation for 6LoWPAN over
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* Bluetooth Low Energy. The specification is very similar to 6LoWPAN,
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* so most of the code is re-used.
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* Compared to 6LoWPAN, much functionality is already implemented in
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* lower BLE layers (fragmenting, session management,...).
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*
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* Usage:
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* - add this netif
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* - don't add IPv4 addresses (no IPv4 support in RFC7668), pass 'NULL','NULL','NULL'
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* - use the BLE to EUI64 conversation util to create an IPv6 link-local address from the BLE MAC (@ref ble_addr_to_eui64)
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* - input function: @ref rfc7668_input
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* - set the link output function, which transmits output data to an established L2CAP channel
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* - If data arrives (HCI event "L2CAP_DATA_PACKET"):
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* - allocate a @ref PBUF_RAW buffer
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* - let the pbuf struct point to the incoming data or copy it to the buffer
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* - call netif->input
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*
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* @todo:
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* - further testing
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* - support compression contexts
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* - support multiple addresses
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* - support multicast
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* - support neighbor discovery
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*/
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#include "netif/lowpan6_ble.h"
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#if LWIP_IPV6
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#include "lwip/ip.h"
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#include "lwip/pbuf.h"
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#include "lwip/ip_addr.h"
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#include "lwip/netif.h"
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#include "lwip/nd6.h"
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#include "lwip/mem.h"
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#include "lwip/udp.h"
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#include "lwip/tcpip.h"
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#include "lwip/snmp.h"
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#include <string.h>
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#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
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/** context memory, containing IPv6 addresses */
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static ip6_addr_t rfc7668_context[LWIP_6LOWPAN_NUM_CONTEXTS];
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#else
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#define rfc7668_context NULL
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#endif
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static struct lowpan6_link_addr rfc7668_local_addr;
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static struct lowpan6_link_addr rfc7668_peer_addr;
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/**
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* @ingroup rfc7668if
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* convert BT address to EUI64 addr
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*
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* This method converts a Bluetooth MAC address to an EUI64 address,
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* which is used within IPv6 communication
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*
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* @param dst IPv6 destination space
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* @param src BLE MAC address source
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* @param public_addr If the LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS
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* option is set, bit 0x02 will be set if param=0 (no public addr); cleared otherwise
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*
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* @see LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS
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*/
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void
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ble_addr_to_eui64(uint8_t *dst, const uint8_t *src, int public_addr)
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{
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/* according to RFC7668 ch 3.2.2. */
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memcpy(dst, src, 3);
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dst[3] = 0xFF;
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dst[4] = 0xFE;
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memcpy(&dst[5], &src[3], 3);
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#if LWIP_RFC7668_LINUX_WORKAROUND_PUBLIC_ADDRESS
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if(public_addr) {
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dst[0] &= ~0x02;
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} else {
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dst[0] |= 0x02;
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}
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#else
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LWIP_UNUSED_ARG(public_addr);
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#endif
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}
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/**
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* @ingroup rfc7668if
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* convert EUI64 address to Bluetooth MAC addr
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*
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* This method converts an EUI64 address to a Bluetooth MAC address,
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*
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* @param dst BLE MAC address destination
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* @param src IPv6 source
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*
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*/
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void
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eui64_to_ble_addr(uint8_t *dst, const uint8_t *src)
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{
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/* according to RFC7668 ch 3.2.2. */
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memcpy(dst,src,3);
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memcpy(&dst[3],&src[5],3);
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}
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/** Set an address used for stateful compression.
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* This expects an address of 6 or 8 bytes.
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*/
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static err_t
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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)
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{
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if ((in_addr == NULL) || (addr == NULL)) {
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return ERR_VAL;
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}
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if (is_mac_48) {
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if (in_addr_len != 6) {
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return ERR_VAL;
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}
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addr->addr_len = 8;
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ble_addr_to_eui64(addr->addr, in_addr, is_public_addr);
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} else {
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if (in_addr_len != 8) {
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return ERR_VAL;
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}
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addr->addr_len = 8;
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memcpy(addr->addr, in_addr, 8);
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}
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return ERR_OK;
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}
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/** Set the local address used for stateful compression.
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* This expects an address of 8 bytes.
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*/
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err_t
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rfc7668_set_local_addr_eui64(struct netif *netif, const u8_t *local_addr, size_t local_addr_len)
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{
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/* netif not used for now, the address is stored globally... */
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LWIP_UNUSED_ARG(netif);
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return rfc7668_set_addr(&rfc7668_local_addr, local_addr, local_addr_len, 0, 0);
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}
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/** Set the local address used for stateful compression.
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* This expects an address of 6 bytes.
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*/
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err_t
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rfc7668_set_local_addr_mac48(struct netif *netif, const u8_t *local_addr, size_t local_addr_len, int is_public_addr)
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{
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/* netif not used for now, the address is stored globally... */
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LWIP_UNUSED_ARG(netif);
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return rfc7668_set_addr(&rfc7668_local_addr, local_addr, local_addr_len, 1, is_public_addr);
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}
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/** Set the peer address used for stateful compression.
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* This expects an address of 8 bytes.
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*/
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err_t
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rfc7668_set_peer_addr_eui64(struct netif *netif, const u8_t *peer_addr, size_t peer_addr_len)
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{
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/* netif not used for now, the address is stored globally... */
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LWIP_UNUSED_ARG(netif);
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return rfc7668_set_addr(&rfc7668_peer_addr, peer_addr, peer_addr_len, 0, 0);
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}
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/** Set the peer address used for stateful compression.
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* This expects an address of 6 bytes.
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*/
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err_t
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rfc7668_set_peer_addr_mac48(struct netif *netif, const u8_t *peer_addr, size_t peer_addr_len, int is_public_addr)
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{
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/* netif not used for now, the address is stored globally... */
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LWIP_UNUSED_ARG(netif);
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return rfc7668_set_addr(&rfc7668_peer_addr, peer_addr, peer_addr_len, 1, is_public_addr);
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}
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/** Encapsulate IPv6 frames for BLE transmission
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*
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* This method implements the IPv6 header compression:
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* *) According to RFC6282
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* *) See Figure 2, contains base format of bit positions
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* *) Fragmentation not necessary (done at L2CAP layer of BLE)
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* @note Currently the pbuf allocation uses 256 bytes. If longer packets are used (possible due to MTU=1480Bytes), increase it here!
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*
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* @param p Pbuf struct, containing the payload data
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* @param netif Output network interface. Should be of RFC7668 type
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*
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* @return Same as netif->output.
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*/
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static err_t
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rfc7668_compress(struct netif *netif, struct pbuf *p)
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{
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struct pbuf *p_frag;
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u16_t remaining_len;
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u8_t *buffer;
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u8_t lowpan6_header_len;
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u8_t hidden_header_len;
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err_t err;
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LWIP_ASSERT("lowpan6_frag: netif->linkoutput not set", netif->linkoutput != NULL);
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#if LWIP_6LOWPAN_IPHC
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/* We'll use a dedicated pbuf for building BLE fragments.
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* We'll over-allocate it by the bytes saved for header compression.
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*/
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p_frag = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
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if (p_frag == NULL) {
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MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
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return ERR_MEM;
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}
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LWIP_ASSERT("this needs a pbuf in one piece", p_frag->len == p_frag->tot_len);
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/* Write IP6 header (with IPHC). */
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buffer = (u8_t*)p_frag->payload;
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err = lowpan6_compress_headers(netif, (u8_t *)p->payload, p->len, buffer, p_frag->len,
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&lowpan6_header_len, &hidden_header_len, rfc7668_context, &rfc7668_local_addr, &rfc7668_peer_addr);
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if (err != ERR_OK) {
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MIB2_STATS_NETIF_INC(netif, ifoutdiscards);
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pbuf_free(p_frag);
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return err;
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}
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pbuf_remove_header(p, hidden_header_len);
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/* Calculate remaining packet length */
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remaining_len = p->tot_len;
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/* Copy IPv6 packet */
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pbuf_copy_partial(p, buffer + lowpan6_header_len, remaining_len, 0);
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/* Calculate frame length */
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p_frag->len = p_frag->tot_len = remaining_len + lowpan6_header_len;
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/* send the packet */
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MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p_frag->tot_len);
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LWIP_DEBUGF(LWIP_LOWPAN6_DEBUG|LWIP_DBG_TRACE, ("rfc7668_output: sending packet %p\n", (void *)p));
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err = netif->linkoutput(netif, p_frag);
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pbuf_free(p_frag);
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return err;
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#else /* LWIP_6LOWPAN_IPHC */
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/* 6LoWPAN over BLE requires IPHC! */
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return ERR_IF;
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#endif/* LWIP_6LOWPAN_IPHC */
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}
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/**
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* @ingroup rfc7668if
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* Set context id IPv6 address
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*
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* Store one IPv6 address to a given context id.
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*
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* @param idx Context id
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* @param context IPv6 addr for this context
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*
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* @return ERR_OK (if everything is fine), ERR_ARG (if the context id is out of range), ERR_VAL (if contexts disabled)
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*/
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err_t
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rfc7668_set_context(u8_t idx, const ip6_addr_t *context)
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{
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#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
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/* check if the ID is possible */
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if (idx >= LWIP_6LOWPAN_NUM_CONTEXTS) {
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return ERR_ARG;
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}
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/* copy IPv6 address to context storage */
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ip6_addr_set(&rfc7668_context[idx], context);
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return ERR_OK;
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#else
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LWIP_UNUSED_ARG(idx);
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LWIP_UNUSED_ARG(context);
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return ERR_VAL;
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#endif
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}
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/**
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* @ingroup rfc7668if
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* Compress outgoing IPv6 packet and pass it on to netif->linkoutput
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*
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* @param netif The lwIP network interface which the IP packet will be sent on.
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* @param q The pbuf(s) containing the IP packet to be sent.
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* @param ip6addr The IP address of the packet destination.
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*
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* @return See rfc7668_compress
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*/
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err_t
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rfc7668_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
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{
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/* dst ip6addr is not used here, we only have one peer */
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LWIP_UNUSED_ARG(ip6addr);
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return rfc7668_compress(netif, q);
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}
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/**
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* @ingroup rfc7668if
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* Process a received raw payload from an L2CAP channel
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*
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* @param p the received packet, p->payload pointing to the
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* IPv6 header (maybe compressed)
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* @param netif the network interface on which the packet was received
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*
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* @return ERR_OK if everything was fine
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*/
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err_t
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rfc7668_input(struct pbuf * p, struct netif *netif)
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{
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u8_t * puc;
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MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
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/* Load first header byte */
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puc = (u8_t*)p->payload;
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/* no IP header compression */
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if (*puc == 0x41) {
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LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, removing dispatch: 0x%2x \n", *puc));
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/* This is a complete IPv6 packet, just skip header byte. */
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pbuf_remove_header(p, 1);
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/* IPHC header compression */
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} else if ((*puc & 0xe0 )== 0x60) {
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LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, decompress dispatch: 0x%2x \n", *puc));
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/* IPv6 headers are compressed using IPHC. */
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p = lowpan6_decompress(p, 0, rfc7668_context, &rfc7668_peer_addr, &rfc7668_local_addr);
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/* if no pbuf is returned, handle as discarded packet */
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if (p == NULL) {
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MIB2_STATS_NETIF_INC(netif, ifindiscards);
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return ERR_OK;
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}
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/* invalid header byte, discard */
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} else {
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LWIP_DEBUGF(LWIP_LOWPAN6_DECOMPRESSION_DEBUG, ("Completed packet, discarding: 0x%2x \n", *puc));
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MIB2_STATS_NETIF_INC(netif, ifindiscards);
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pbuf_free(p);
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return ERR_OK;
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}
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/* @todo: distinguish unicast/multicast */
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MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
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#if LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG
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{
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u16_t i;
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LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("IPv6 payload:\n"));
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for (i = 0; i < p->len; i++) {
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if ((i%4)==0) {
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LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("\n"));
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}
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LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("%2X ", *((uint8_t *)p->payload+i)));
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}
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LWIP_DEBUGF(LWIP_RFC7668_IP_UNCOMPRESSED_DEBUG, ("\np->len: %d\n", p->len));
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}
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#endif
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/* pass data to ip6_input */
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return ip6_input(p, netif);
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}
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/**
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* @ingroup rfc7668if
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* Initialize the netif
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*
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* No flags are used (broadcast not possible, not ethernet, ...)
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* The shortname for this netif is "BT"
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*
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* @param netif the network interface to be initialized as RFC7668 netif
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*
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* @return ERR_OK if everything went fine
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*/
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err_t
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rfc7668_if_init(struct netif *netif)
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{
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netif->name[0] = 'b';
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netif->name[1] = 't';
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/* local function as IPv6 output */
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netif->output_ip6 = rfc7668_output;
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MIB2_INIT_NETIF(netif, snmp_ifType_other, 0);
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/* maximum transfer unit, set according to RFC7668 ch2.4 */
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netif->mtu = IP6_MIN_MTU_LENGTH;
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/* no flags set (no broadcast, ethernet,...)*/
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netif->flags = 0;
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/* everything fine */
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return ERR_OK;
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}
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#if !NO_SYS
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/**
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* Pass a received packet to tcpip_thread for input processing
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*
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* @param p the received packet, p->payload pointing to the
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* IEEE 802.15.4 header.
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* @param inp the network interface on which the packet was received
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*
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* @return see @ref tcpip_inpkt, same return values
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*/
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err_t
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tcpip_rfc7668_input(struct pbuf *p, struct netif *inp)
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{
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/* send data to upper layer, return the result */
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return tcpip_inpkt(p, inp, rfc7668_input);
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}
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#endif /* !NO_SYS */
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#endif /* LWIP_IPV6 */
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