#include <string.h>
#include <stdio.h>
#include "jsmn.h"
#include "picocoap.h"
#include "compressor.h"
#include "schc_config.h"
#include "rules/rule_config.h"

Functions
static void	get_node_ip (schc_ipaddr_t *node_ip)
	Get the node its IP address as set during initialization. More...

static struct schc_device *	get_device_by_id (uint32_t device_id)
	Get a device by it's id. More...

int8_t	set_rule_id (struct schc_rule_t schc_rule, uint8_t data)

struct schc_rule_t *	get_schc_rule_by_reliability_mode (struct schc_rule_t *schc_rule, reliability_mode mode, uint32_t device_id)

static struct schc_rule_t *	get_schc_rule_by_layer_ids (uint8_t ip_rule_id, uint8_t udp_rule_id, uint8_t coap_rule_id, uint32_t device_id, reliability_mode mode)

struct schc_rule_t *	get_schc_rule_by_rule_id (uint8_t *rule_arr, uint32_t device_id)

static uint8_t	compress (schc_bitarray_t dst, schc_bitarray_t src, const struct schc_layer_rule_t *rule, direction DI)
	The compression mechanism. More...

static uint8_t	decompress (struct schc_layer_rule_t rule, schc_bitarray_t src, schc_bitarray_t *dst, direction DI)
	The decompression mechanism. More...

static struct schc_layer_rule_t *	schc_find_rule_from_header (schc_bitarray_t *src, uint32_t device_id, schc_layer_t layer, direction DI)
	Find a matching rule for a layer. More...

static void	swap_ipv6_source_and_destination (uint8_t *ptr)
	Swaps the IPv6 source and destination. More...

static uint8_t	equal (struct schc_field target_field, unsigned char field_value, uint16_t field_offset)
	The equal matching operator. More...

static uint8_t	ignore (struct schc_field target_field, unsigned char field_value, uint16_t field_offset)
	The ignore matching operator. More...

static uint8_t	MSB (struct schc_field target_field, unsigned char field_value, uint16_t field_offset)
	The MSB matching operator MSB(x): a match is obtained if the most significant (leftmost) x bits of the packet header field value are equal to the TV in the Rule. More...

static uint8_t	matchmap (struct schc_field target_field, unsigned char field_value, uint16_t field_offset)
	The match-map matching operator match-mapping: With match-mapping, the Target Value is a list of values. More...

static void	set_node_ip (schc_ipaddr_t *node_ip)
	Notifies the compressor about the node its IP address. More...

uint8_t	schc_compressor_init (uint8_t src[16])
	Initializes the SCHC compressor. More...

int16_t	schc_compress (uint8_t data, uint16_t total_length, schc_bitarray_t dst, uint32_t device_id, direction dir, struct schc_rule_t **schc_rule)
	Compresses a CoAP/UDP/IP packet. More...

static uint16_t	compute_length (unsigned char *data, uint16_t data_len)
	Set the packet length for the UDP and IP headers. More...

static uint16_t	chksum (uint16_t sum, const uint8_t *data, uint16_t len)

uint16_t	compute_checksum (unsigned char *data)
	Calculates the UDP checksum and sets the appropriate header fields. More...

uint16_t	schc_decompress (schc_bitarray_t bit_arr, uint8_t buf, uint32_t device_id, uint16_t total_length, direction dir)
	Construct the header from the layered set of rules. More...

Variables
static schc_ipaddr_t	node_ip_6

jsmn_parser	json_parser

jsmntok_t	json_token [JSON_TOKENS]

Function Documentation

◆ chksum()

static uint16_t chksum	(	uint16_t	sum,
		const uint8_t *	data,
		uint16_t	len
	)

static

◆ compress()

static uint8_t compress	(	schc_bitarray_t *	dst,
		schc_bitarray_t *	src,
		const struct schc_layer_rule_t *	rule,
		direction	DI
	)

static

The compression mechanism.

Parameters

dst_arr	the bit array in which to copy the contents to
src_arr	the original header
rule	the rule to match the compression with

Returns: the length length of the compressed header

◆ compute_checksum()

uint16_t compute_checksum ( unsigned char * data )

Calculates the UDP checksum and sets the appropriate header fields.

Parameters

data	pointer to the data packet

Returns: checksum the computed checksum

◆ compute_length()

static uint16_t compute_length	(	unsigned char *	data,
		uint16_t	data_len
	)

static

Set the packet length for the UDP and IP headers.

Parameters

data	pointer to the data packet
data_len	the length of the total packet

Returns: 0

◆ decompress()

static uint8_t decompress	(	struct schc_layer_rule_t *	rule,
		schc_bitarray_t *	src,
		schc_bitarray_t *	dst,
		direction	DI
	)

static

The decompression mechanism.

Parameters

rule	pointer to the rule to use during the decompression
src	the received SCHC bit buffer
dst	the buffer to store the decompressed, original packet

Returns: the length of the decompressed header

◆ equal()

static uint8_t equal	(	struct schc_field *	target_field,
		unsigned char *	field_value,
		uint16_t	field_offset
	)

static

The equal matching operator.

Parameters

target_field	the field from the rule
field_value	the value from the header to compare with the rule value
field_offset	the offset (in bits), starting from the field value pointer

Returns: 1 if the target field matches the field value 0 if the target field doesn't match the field value

◆ get_device_by_id()

static struct schc_device* get_device_by_id ( uint32_t device_id )

static

Get a device by it's id.

Parameters

device_id the id of the device

Returns: schc_device the device which is found NULL if no device was found

◆ get_node_ip()

static void get_node_ip ( schc_ipaddr_t * node_ip )

static

Get the node its IP address as set during initialization.

Returns: node_ip_6 the node its IP address

◆ get_schc_rule_by_layer_ids()

static struct schc_rule_t* get_schc_rule_by_layer_ids	(	uint8_t	ip_rule_id,
		uint8_t	udp_rule_id,
		uint8_t	coap_rule_id,
		uint32_t	device_id,
		reliability_mode	mode
	)

static

◆ get_schc_rule_by_reliability_mode()

struct schc_rule_t* get_schc_rule_by_reliability_mode	(	struct schc_rule_t *	schc_rule,
		reliability_mode	mode,
		uint32_t	device_id
	)

◆ get_schc_rule_by_rule_id()

struct schc_rule_t* get_schc_rule_by_rule_id	(	uint8_t *	rule_arr,
		uint32_t	device_id
	)

◆ ignore()

static uint8_t ignore	(	struct schc_field *	target_field,
		unsigned char *	field_value,
		uint16_t	field_offset
	)

static

The ignore matching operator.

Parameters

target_field	the field from the rule
field_value	the value from the header to compare with the rule value

Returns: 1

◆ matchmap()

static uint8_t matchmap	(	struct schc_field *	target_field,
		unsigned char *	field_value,
		uint16_t	field_offset
	)

static

The match-map matching operator match-mapping: With match-mapping, the Target Value is a list of values.

Each value of the list is identified by an index. Compression is achieved by sending the index instead of the original header field value.

Parameters

target_field	the field from the rule
field_value	the value from the header to compare with the rule value

Returns: 1 if the the field value is equal to one of the values found in the mapping array 0 if no matching value is found in the mapping array

◆ MSB()

static uint8_t MSB	(	struct schc_field *	target_field,
		unsigned char *	field_value,
		uint16_t	field_offset
	)

static

The MSB matching operator MSB(x): a match is obtained if the most significant (leftmost) x bits of the packet header field value are equal to the TV in the Rule.

The x parameter of the MSB MO indicates how many bits are involved in the comparison. If the FL is described as variable, the x parameter must be a multiple of the FL unit. For example, x must be multiple of 8 if the unit of the variable length is bytes.

Parameters

target_field	the field from the rule
field_value	the value from the header to compare with the rule value

Returns: 1 if the MSB of the target field matches the MSB of the field value 0 if the MSB of the target field doesn't match the MSB of the field value

◆ schc_compress()

int16_t schc_compress	(	uint8_t *	data,
		uint16_t	total_length,
		schc_bitarray_t *	dst,
		uint32_t	device_id,
		direction	dir,
		struct schc_rule_t **	schc_rule
	)

Compresses a CoAP/UDP/IP packet.

Parameters

data	pointer to the original packet
total_length	the length of the packet
dst	pointer to the bit array object, where the compressed packet will be stored. Can later be passed to fragmenter
device_id	the device id to find a rule for
direction	the direction of the flow UP: LPWAN to IPv6 or DOWN: IPv6 to LPWAN
device_type	the device type: NETWORK_GATEWAY or DEVICE
schc_rule	a pointer to a schc rule struct to return the rule that was found

Returns: length the length of the compressed packet -1 on a memory overflow

Note: the compressor will only look for rules configured with the NOT_FRAGMENTED reliability mode

◆ schc_compressor_init()

uint8_t schc_compressor_init ( uint8_t src[16] )

Initializes the SCHC compressor.

Parameters

node_ip a pointer to the source it's ip address

Returns: error error codes on error

◆ schc_decompress()

uint16_t schc_decompress	(	schc_bitarray_t *	bit_arr,
		uint8_t *	buf,
		uint32_t	device_id,
		uint16_t	total_length,
		direction	dir
	)

Construct the header from the layered set of rules.

Parameters

data	pointer to the received data
buf	pointer where to save the decompressed packet
device_id	the device its id
total_length	the total length of the received data
direction	the direction of the flow (UP: LPWAN to IPv6, DOWN: IPv6 to LPWAN)

Returns: length length of the newly constructed packet 0 the rule was not found

◆ schc_find_rule_from_header()

static struct schc_layer_rule_t* schc_find_rule_from_header	(	schc_bitarray_t *	src,
		uint32_t	device_id,
		schc_layer_t	layer,
		direction	DI
	)

static

Find a matching rule for a layer.

Parameters

schc_bitarray	the bit array as received from the network note: a conversion is required for CoAP to decode the options
device_id	the device to find an IP rule for
schc_layer	the layer for which to find a rule for

Returns: the rule NULL if no rule is found

◆ set_node_ip()

static void set_node_ip ( schc_ipaddr_t * node_ip )

static

Notifies the compressor about the node its IP address.

Parameters

node_ip pointer to the ip address array

Returns: 0

◆ set_rule_id()

int8_t set_rule_id	(	struct schc_rule_t *	schc_rule,
		uint8_t *	data
	)

◆ swap_ipv6_source_and_destination()

static void swap_ipv6_source_and_destination ( uint8_t * ptr )

static

Swaps the IPv6 source and destination.

Parameters

ptr	pointer to the ipv6 header

Variable Documentation

◆ json_parser

jsmn_parser json_parser

◆ json_token

jsmntok_t json_token[JSON_TOKENS]

◆ node_ip_6

schc_ipaddr_t node_ip_6

static

Functions

Variables

Function Documentation

◆ chksum()

◆ compress()

◆ compute_checksum()

◆ compute_length()

◆ decompress()

◆ equal()

◆ get_device_by_id()

◆ get_node_ip()

◆ get_schc_rule_by_layer_ids()

◆ get_schc_rule_by_reliability_mode()

◆ get_schc_rule_by_rule_id()

◆ ignore()

◆ matchmap()

◆ MSB()

◆ schc_compress()

◆ schc_compressor_init()

◆ schc_decompress()

◆ schc_find_rule_from_header()

◆ set_node_ip()

◆ set_rule_id()

◆ swap_ipv6_source_and_destination()

Variable Documentation

◆ json_parser

◆ json_token

◆ node_ip_6