mbed-os/connectivity/nanostack/sal-stack-nanostack/source/6LoWPAN/ws/ws_mpx_header.c

147 lines
3.9 KiB
C

/*
* Copyright (c) 2018-2019, Arm Limited and affiliates.
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "nsconfig.h"
#include <string.h>
#include "ns_types.h"
#include "ns_list.h"
#include "ns_trace.h"
#include "nsdynmemLIB.h"
#include "common_functions.h"
#include "mac_common_defines.h"
#include "ws_mpx_header.h"
bool ws_llc_mpx_header_frame_parse(uint8_t *ptr, uint16_t length, mpx_msg_t *msg)
{
if (!length) {
return false;
}
memset(msg, 0, sizeof(mpx_msg_t));
bool fragmented_number_present = false;
bool multiplex_id_present = false;
bool fragment_total_size = false;
msg->transfer_type = *ptr & 7;
msg->transaction_id = ((*ptr++ & 0xf8) >> 3);
length--;
switch (msg->transfer_type) {
case MPX_FT_FULL_FRAME:
multiplex_id_present = true;
break;
case MPX_FT_FULL_FRAME_SMALL_MULTILEX_ID:
break;
case MPX_FT_FIRST_OR_SUB_FRAGMENT:
case MPX_FT_LAST_FRAGMENT:
fragmented_number_present = true;
if (length < 2) {
return false;
}
break;
case MPX_FT_ABORT:
if (length == 2) {
fragment_total_size = true;
} else if (length) {
return false;
}
break;
default:
return false;
}
if (fragmented_number_present) {
msg->fragment_number = *ptr++;
length--;
if (msg->fragment_number == 0) { //First fragment
fragment_total_size = true;
multiplex_id_present = true;
}
}
if (fragment_total_size) {
if (length < 2) {
return false;
}
msg->total_upper_layer_size = common_read_16_bit_inverse(ptr);
ptr += 2;
length -= 2;
}
if (multiplex_id_present) {
if (length < 3) {
return false;
}
msg->multiplex_id = common_read_16_bit_inverse(ptr);
ptr += 2;
length -= 2;
}
msg->frame_ptr = ptr;
msg->frame_length = length;
return true;
}
uint8_t *ws_llc_mpx_header_write(uint8_t *ptr, const mpx_msg_t *msg)
{
bool fragmented_number_present = false;
bool multiplex_id_present = false;
bool fragment_total_size = false;
*ptr = msg->transfer_type;
*ptr++ |= ((msg->transaction_id << 3) & 0xf8);
switch (msg->transfer_type) {
case MPX_FT_FULL_FRAME:
multiplex_id_present = true;
break;
case MPX_FT_FULL_FRAME_SMALL_MULTILEX_ID:
break;
case MPX_FT_FIRST_OR_SUB_FRAGMENT:
case MPX_FT_LAST_FRAGMENT:
fragmented_number_present = true;
if (msg->fragment_number == 0) {
fragment_total_size = true;
multiplex_id_present = true;
}
break;
case MPX_FT_ABORT:
if (msg->total_upper_layer_size) {
fragment_total_size = true;
}
break;
default:
break;
}
if (fragmented_number_present) {
*ptr++ = msg->fragment_number;
}
if (fragment_total_size) {
ptr = common_write_16_bit_inverse(msg->total_upper_layer_size, ptr);
}
if (multiplex_id_present) {
ptr = common_write_16_bit_inverse(msg->multiplex_id, ptr);
}
return ptr;
}