diff options
Diffstat (limited to 'include/openbsc/gprs_sndcp_dcomp.h')
-rw-r--r-- | include/openbsc/gprs_sndcp_dcomp.h | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/include/openbsc/gprs_sndcp_dcomp.h b/include/openbsc/gprs_sndcp_dcomp.h new file mode 100644 index 000000000..a76b4a4b3 --- /dev/null +++ b/include/openbsc/gprs_sndcp_dcomp.h @@ -0,0 +1,53 @@ +/* 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); |