54 lines
2.0 KiB
C
54 lines
2.0 KiB
C
/* GPRS SNDCP data compression handler */
|
|
|
|
/* (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
|
|
* All Rights Reserved
|
|
*
|
|
* Author: Philipp Maier
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU Affero General Public License as published by
|
|
* the Free Software Foundation; either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU Affero General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Affero General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <stdint.h>
|
|
#include <osmocom/core/linuxlist.h>
|
|
#include <openbsc/gprs_sndcp_comp.h>
|
|
|
|
/* Note: The decompressed packet may have a maximum size of:
|
|
* Return value * MAX_DATADECOMPR_FAC */
|
|
#define MAX_DATADECOMPR_FAC 10
|
|
|
|
/* Note: In unacknowledged mode (SN_UNITDATA), the comression state is reset
|
|
* for every NPDU. The compressor needs a reasonably large payload to operate
|
|
* effectively (yield positive compression gain). For packets shorter than 100
|
|
* byte, no positive compression gain can be expected so we will skip the
|
|
* compression for short packets. */
|
|
#define MIN_COMPR_PAYLOAD 100
|
|
|
|
/* Initalize data compression */
|
|
int gprs_sndcp_dcomp_init(const void *ctx, struct gprs_sndcp_comp *comp_entity,
|
|
const struct gprs_sndcp_comp_field *comp_field);
|
|
|
|
/* Terminate data compression */
|
|
void gprs_sndcp_dcomp_term(struct gprs_sndcp_comp *comp_entity);
|
|
|
|
/* Expand packet */
|
|
int gprs_sndcp_dcomp_expand(uint8_t *data, unsigned int len, uint8_t pcomp,
|
|
const struct llist_head *comp_entities);
|
|
|
|
/* Compress packet */
|
|
int gprs_sndcp_dcomp_compress(uint8_t *data, unsigned int len, uint8_t *pcomp,
|
|
const struct llist_head *comp_entities,
|
|
uint8_t nsapi);
|