contiki/core/net/mac/frame802154.c

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/*
*
* Copyright (c) 2008, Swedish Institute of Computer Science
* All rights reserved.
*
* Additional fixes for AVR contributed by:
*
* Colin O'Flynn coflynn@newae.com
* Eric Gnoske egnoske@gmail.com
* Blake Leverett bleverett@gmail.com
* Mike Vidales mavida404@gmail.com
* Kevin Brown kbrown3@uccs.edu
* Nate Bohlmann nate@elfwerks.com
*
* Additional fixes for MSP430 contributed by:
* Joakim Eriksson
* Niclas Finne
* Nicolas Tsiftes
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
*
*/
/*
* \brief This file is where the main functions that relate to frame
* manipulation will reside.
*/
/**
* \addtogroup frame802154
* @{
*/
/**
* \file
* \brief 802.15.4 frame creation and parsing functions
*
* This file converts to and from a structure to a packed 802.15.4
* frame.
*/
#include "sys/cc.h"
#include "net/mac/frame802154.h"
#include <string.h>
/**
* \brief Structure that contains the lengths of the various addressing and security fields
* in the 802.15.4 header. This structure is used in \ref frame802154_create()
*/
typedef struct {
uint8_t dest_pid_len; /**< Length (in bytes) of destination PAN ID field */
uint8_t dest_addr_len; /**< Length (in bytes) of destination address field */
uint8_t src_pid_len; /**< Length (in bytes) of source PAN ID field */
uint8_t src_addr_len; /**< Length (in bytes) of source address field */
uint8_t aux_sec_len; /**< Length (in bytes) of aux security header field */
} field_length_t;
/*----------------------------------------------------------------------------*/
CC_INLINE static uint8_t
addr_len(uint8_t mode)
{
switch(mode) {
case FRAME802154_SHORTADDRMODE: /* 16-bit address */
return 2;
case FRAME802154_LONGADDRMODE: /* 64-bit address */
return 8;
default:
return 0;
}
}
/*----------------------------------------------------------------------------*/
static void
field_len(frame802154_t *p, field_length_t *flen)
{
/* init flen to zeros */
memset(flen, 0, sizeof(field_length_t));
/* Determine lengths of each field based on fcf and other args */
if(p->fcf.dest_addr_mode & 3) {
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flen->dest_pid_len = 2;
}
if(p->fcf.src_addr_mode & 3) {
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flen->src_pid_len = 2;
}
/* Set PAN ID compression bit if src pan id matches dest pan id. */
if(p->fcf.dest_addr_mode & 3 && p->fcf.src_addr_mode & 3 &&
p->src_pid == p->dest_pid) {
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p->fcf.panid_compression = 1;
/* compressed header, only do dest pid */
flen->src_pid_len = 0;
} else {
p->fcf.panid_compression = 0;
}
/* determine address lengths */
flen->dest_addr_len = addr_len(p->fcf.dest_addr_mode & 3);
flen->src_addr_len = addr_len(p->fcf.src_addr_mode & 3);
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/* Aux security header */
if(p->fcf.security_enabled & 1) {
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/* TODO Aux security header not yet implemented */
#if 0
switch(p->aux_hdr.security_control.key_id_mode) {
case 0:
flen->aux_sec_len = 5; /* minimum value */
break;
case 1:
flen->aux_sec_len = 6;
break;
case 2:
flen->aux_sec_len = 10;
break;
case 3:
flen->aux_sec_len = 14;
break;
default:
break;
}
#endif
}
}
/*----------------------------------------------------------------------------*/
/**
* \brief Calculates the length of the frame header. This function is
* meant to be called by a higher level function, that interfaces to a MAC.
*
* \param p Pointer to frame802154_t_t struct, which specifies the
* frame to send.
*
* \return The length of the frame header.
*/
int
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frame802154_hdrlen(frame802154_t *p)
{
field_length_t flen;
field_len(p, &flen);
return 3 + flen.dest_pid_len + flen.dest_addr_len +
flen.src_pid_len + flen.src_addr_len + flen.aux_sec_len;
}
/*----------------------------------------------------------------------------*/
/**
* \brief Creates a frame for transmission over the air. This function is
* meant to be called by a higher level function, that interfaces to a MAC.
*
* \param p Pointer to frame802154_t struct, which specifies the
* frame to send.
*
* \param buf Pointer to the buffer to use for the frame.
*
* \param buf_len The length of the buffer to use for the frame.
*
* \return The length of the frame header or 0 if there was
* insufficient space in the buffer for the frame headers.
*/
int
frame802154_create(frame802154_t *p, uint8_t *buf, int buf_len)
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{
int c;
field_length_t flen;
uint8_t *tx_frame_buffer;
uint8_t pos;
field_len(p, &flen);
if(3 + flen.dest_pid_len + flen.dest_addr_len +
flen.src_pid_len + flen.src_addr_len + flen.aux_sec_len > buf_len) {
/* Too little space for headers. */
return 0;
}
/* OK, now we have field lengths. Time to actually construct */
/* the outgoing frame, and store it in tx_frame_buffer */
tx_frame_buffer = buf;
tx_frame_buffer[0] = (p->fcf.frame_type & 7) |
((p->fcf.security_enabled & 1) << 3) |
((p->fcf.frame_pending & 1) << 4) |
((p->fcf.ack_required & 1) << 5) |
((p->fcf.panid_compression & 1) << 6);
tx_frame_buffer[1] = ((p->fcf.dest_addr_mode & 3) << 2) |
((p->fcf.frame_version & 3) << 4) |
((p->fcf.src_addr_mode & 3) << 6);
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/* sequence number */
tx_frame_buffer[2] = p->seq;
pos = 3;
/* Destination PAN ID */
if(flen.dest_pid_len == 2) {
tx_frame_buffer[pos++] = p->dest_pid & 0xff;
tx_frame_buffer[pos++] = (p->dest_pid >> 8) & 0xff;
}
/* Destination address */
for(c = flen.dest_addr_len; c > 0; c--) {
tx_frame_buffer[pos++] = p->dest_addr[c - 1];
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}
/* Source PAN ID */
if(flen.src_pid_len == 2) {
tx_frame_buffer[pos++] = p->src_pid & 0xff;
tx_frame_buffer[pos++] = (p->src_pid >> 8) & 0xff;
}
/* Source address */
for(c = flen.src_addr_len; c > 0; c--) {
tx_frame_buffer[pos++] = p->src_addr[c - 1];
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}
/* Aux header */
if(flen.aux_sec_len) {
/* TODO Aux security header not yet implemented */
/* pos += flen.aux_sec_len; */
}
return (int)pos;
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}
/*----------------------------------------------------------------------------*/
/**
* \brief Parses an input frame. Scans the input frame to find each
* section, and stores the information of each section in a
* frame802154_t structure.
*
* \param data The input data from the radio chip.
* \param len The size of the input data
* \param pf The frame802154_t struct to store the parsed frame information.
*/
int
frame802154_parse(uint8_t *data, int len, frame802154_t *pf)
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{
uint8_t *p;
frame802154_fcf_t fcf;
int c;
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if(len < 3) {
return 0;
}
p = data;
/* decode the FCF */
fcf.frame_type = p[0] & 7;
fcf.security_enabled = (p[0] >> 3) & 1;
fcf.frame_pending = (p[0] >> 4) & 1;
fcf.ack_required = (p[0] >> 5) & 1;
fcf.panid_compression = (p[0] >> 6) & 1;
fcf.dest_addr_mode = (p[1] >> 2) & 3;
fcf.frame_version = (p[1] >> 4) & 3;
fcf.src_addr_mode = (p[1] >> 6) & 3;
/* copy fcf and seqNum */
memcpy(&pf->fcf, &fcf, sizeof(frame802154_fcf_t));
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pf->seq = p[2];
p += 3; /* Skip first three bytes */
/* Destination address, if any */
if(fcf.dest_addr_mode) {
/* Destination PAN */
pf->dest_pid = p[0] + (p[1] << 8);
p += 2;
/* Destination address */
/* l = addr_len(fcf.dest_addr_mode); */
/* for(c = 0; c < l; c++) { */
/* pf->dest_addr.u8[c] = p[l - c - 1]; */
/* } */
/* p += l; */
if(fcf.dest_addr_mode == FRAME802154_SHORTADDRMODE) {
linkaddr_copy((linkaddr_t *)&(pf->dest_addr), &linkaddr_null);
pf->dest_addr[0] = p[1];
pf->dest_addr[1] = p[0];
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p += 2;
} else if(fcf.dest_addr_mode == FRAME802154_LONGADDRMODE) {
for(c = 0; c < 8; c++) {
pf->dest_addr[c] = p[7 - c];
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}
p += 8;
}
} else {
linkaddr_copy((linkaddr_t *)&(pf->dest_addr), &linkaddr_null);
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pf->dest_pid = 0;
}
/* Source address, if any */
if(fcf.src_addr_mode) {
/* Source PAN */
if(!fcf.panid_compression) {
pf->src_pid = p[0] + (p[1] << 8);
p += 2;
} else {
pf->src_pid = pf->dest_pid;
}
/* Source address */
/* l = addr_len(fcf.src_addr_mode); */
/* for(c = 0; c < l; c++) { */
/* pf->src_addr.u8[c] = p[l - c - 1]; */
/* } */
/* p += l; */
if(fcf.src_addr_mode == FRAME802154_SHORTADDRMODE) {
linkaddr_copy((linkaddr_t *)&(pf->src_addr), &linkaddr_null);
pf->src_addr[0] = p[1];
pf->src_addr[1] = p[0];
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p += 2;
} else if(fcf.src_addr_mode == FRAME802154_LONGADDRMODE) {
for(c = 0; c < 8; c++) {
pf->src_addr[c] = p[7 - c];
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}
p += 8;
}
} else {
linkaddr_copy((linkaddr_t *)&(pf->src_addr), &linkaddr_null);
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pf->src_pid = 0;
}
if(fcf.security_enabled) {
/* TODO aux security header, not yet implemented */
/* return 0; */
}
/* header length */
c = p - data;
/* payload length */
pf->payload_len = (len - c);
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/* payload */
pf->payload = p;
/* return header length if successful */
return c > len ? 0 : c;
}
/** \} */