| /* 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 <osmocom/sgsn/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); |