diff options
Diffstat (limited to 'openbsc/src/gprs/gprs_sndcp_dcomp.c')
-rw-r--r-- | openbsc/src/gprs/gprs_sndcp_dcomp.c | 358 |
1 files changed, 0 insertions, 358 deletions
diff --git a/openbsc/src/gprs/gprs_sndcp_dcomp.c b/openbsc/src/gprs/gprs_sndcp_dcomp.c deleted file mode 100644 index b0f95b486..000000000 --- a/openbsc/src/gprs/gprs_sndcp_dcomp.c +++ /dev/null @@ -1,358 +0,0 @@ -/* GPRS SNDCP data compression handler */ - -/* (C) 2016 by Sysmocom s.f.m.c. GmbH - * 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/>. - * - */ - -#include <stdio.h> -#include <string.h> -#include <stdint.h> -#include <math.h> -#include <errno.h> -#include <stdbool.h> - -#include <osmocom/core/utils.h> -#include <osmocom/core/msgb.h> -#include <osmocom/core/linuxlist.h> -#include <osmocom/core/talloc.h> -#include <osmocom/gsm/tlv.h> - -#include <openbsc/gprs_llc.h> -#include <openbsc/sgsn.h> -#include <openbsc/gprs_sndcp_xid.h> -#include <openbsc/v42bis.h> -#include <openbsc/v42bis_private.h> -#include <openbsc/debug.h> -#include <openbsc/gprs_sndcp_comp.h> -#include <openbsc/gprs_sndcp_dcomp.h> - -/* A struct to capture the output data of compressor and decompressor */ -struct v42bis_output_buffer { - uint8_t *buf; - uint8_t *buf_pointer; - int len; -}; - -/* Handler to capture the output data from the compressor */ -void tx_v42bis_frame_handler(void *user_data, const uint8_t *pkt, int len) -{ - struct v42bis_output_buffer *output_buffer = - (struct v42bis_output_buffer *)user_data; - memcpy(output_buffer->buf_pointer, pkt, len); - output_buffer->buf_pointer += len; - output_buffer->len += len; - return; -} - -/* Handler to capture the output data from the decompressor */ -void rx_v42bis_data_handler(void *user_data, const uint8_t *buf, int len) -{ - struct v42bis_output_buffer *output_buffer = - (struct v42bis_output_buffer *)user_data; - memcpy(output_buffer->buf_pointer, buf, len); - output_buffer->buf_pointer += len; - output_buffer->len += len; - return; -} - -/* 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) -{ - /* Note: This function is automatically called from - * gprs_sndcp_comp.c when a new data compression - * entity is created by gprs_sndcp.c */ - - OSMO_ASSERT(comp_entity); - OSMO_ASSERT(comp_field); - - if (comp_entity->compclass == SNDCP_XID_DATA_COMPRESSION - && comp_entity->algo == V42BIS) { - OSMO_ASSERT(comp_field->v42bis_params); - comp_entity->state = - v42bis_init(ctx, NULL, comp_field->v42bis_params->p0, - comp_field->v42bis_params->p1, - comp_field->v42bis_params->p2, - &tx_v42bis_frame_handler, NULL, - V42BIS_MAX_OUTPUT_LENGTH, - &rx_v42bis_data_handler, NULL, - V42BIS_MAX_OUTPUT_LENGTH); - LOGP(DSNDCP, LOGL_INFO, - "V.42bis data compression initalized.\n"); - return 0; - } - - /* Just in case someone tries to initalize an unknown or unsupported - * data compresson. Since everything is checked during the SNDCP - * negotiation process, this should never happen! */ - OSMO_ASSERT(false); -} - -/* Terminate data compression */ -void gprs_sndcp_dcomp_term(struct gprs_sndcp_comp *comp_entity) -{ - /* Note: This function is automatically called from - * gprs_sndcp_comp.c when a data compression - * entity is deleted by gprs_sndcp.c */ - - OSMO_ASSERT(comp_entity); - - if (comp_entity->compclass == SNDCP_XID_DATA_COMPRESSION - && comp_entity->algo == V42BIS) { - if (comp_entity->state) { - v42bis_free((v42bis_state_t *) comp_entity->state); - comp_entity->state = NULL; - } - LOGP(DSNDCP, LOGL_INFO, - "V.42bis data compression terminated.\n"); - return; - } - - /* Just in case someone tries to terminate an unknown or unsupported - * data compresson. Since everything is checked during the SNDCP - * negotiation process, this should never happen! */ - OSMO_ASSERT(false); -} - -/* Perform a full reset of the V.42bis compression state */ -static void v42bis_reset(v42bis_state_t *comp) -{ - /* This function performs a complete reset of the V.42bis compression - * state by reinitalizing the state withe the previously negotiated - * parameters. */ - - int p0, p1, p2; - p0 = comp->decompress.v42bis_parm_p0 | comp->compress.v42bis_parm_p0; - p1 = comp->decompress.v42bis_parm_n2; - p2 = comp->decompress.v42bis_parm_n7; - - DEBUGP(DSNDCP, "Resetting compression state: %p, p0=%d, p1=%d, p2=%d\n", - comp, p0, p1, p2); - - v42bis_init(NULL, comp, p0, p1, p2, &tx_v42bis_frame_handler, NULL, - V42BIS_MAX_OUTPUT_LENGTH, &rx_v42bis_data_handler, NULL, - V42BIS_MAX_OUTPUT_LENGTH); -} - -/* Compress a packet using V.42bis data compression */ -static int v42bis_compress_unitdata(uint8_t *pcomp_index, uint8_t *data, - unsigned int len, v42bis_state_t *comp) -{ - /* Note: This implementation may only be used to compress SN_UNITDATA - * packets, since it resets the compression state for each NPDU. */ - - uint8_t *data_o; - int rc; - int skip = 0; - struct v42bis_output_buffer compressed_data; - - /* Don't bother with short packets */ - if (len < MIN_COMPR_PAYLOAD) - skip = 1; - - /* Skip if compression is not enabled for TX direction */ - if (!comp->compress.v42bis_parm_p0) - skip = 1; - - /* Skip compression */ - if (skip) { - *pcomp_index = 0; - return len; - } - - /* Reset V.42bis compression state */ - v42bis_reset(comp); - - /* Run compressor */ - data_o = talloc_zero_size(comp, len * MAX_DATADECOMPR_FAC); - compressed_data.buf = data_o; - compressed_data.buf_pointer = data_o; - compressed_data.len = 0; - comp->compress.user_data = (&compressed_data); - rc = v42bis_compress(comp, data, len); - if (rc < 0) { - LOGP(DSNDCP, LOGL_ERROR, - "Data compression failed, skipping...\n"); - skip = 1; - } - rc = v42bis_compress_flush(comp); - if (rc < 0) { - LOGP(DSNDCP, LOGL_ERROR, - "Data compression failed, skipping...\n"); - skip = 1; - } - - /* The compressor might yield negative compression gain, in - * this case, we just decide to send the packat as normal, - * uncompressed payload => skip compresssion */ - if (compressed_data.len >= len) { - LOGP(DSNDCP, LOGL_ERROR, - "Data compression ineffective, skipping...\n"); - skip = 1; - } - - /* Skip compression */ - if (skip) { - *pcomp_index = 0; - talloc_free(data_o); - return len; - } - - *pcomp_index = 1; - memcpy(data, data_o, compressed_data.len); - talloc_free(data_o); - - return compressed_data.len; -} - -/* Expand a packet using V.42bis data compression */ -static int v42bis_expand_unitdata(uint8_t *data, unsigned int len, - uint8_t pcomp_index, v42bis_state_t *comp) -{ - /* Note: This implementation may only be used to compress SN_UNITDATA - * packets, since it resets the compression state for each NPDU. */ - - int rc; - struct v42bis_output_buffer uncompressed_data; - uint8_t *data_i; - - /* Skip when the packet is marked as uncompressed */ - if (pcomp_index == 0) { - return len; - } - - /* Reset V.42bis compression state */ - v42bis_reset(comp); - - /* Decompress packet */ - data_i = talloc_zero_size(comp, len); - memcpy(data_i, data, len); - uncompressed_data.buf = data; - uncompressed_data.buf_pointer = data; - uncompressed_data.len = 0; - comp->decompress.user_data = (&uncompressed_data); - rc = v42bis_decompress(comp, data_i, len); - talloc_free(data_i); - if (rc < 0) - return -EINVAL; - rc = v42bis_decompress_flush(comp); - if (rc < 0) - return -EINVAL; - - return uncompressed_data.len; -} - -/* Expand packet */ -int gprs_sndcp_dcomp_expand(uint8_t *data, unsigned int len, uint8_t pcomp, - const struct llist_head *comp_entities) -{ - int rc; - uint8_t pcomp_index = 0; - struct gprs_sndcp_comp *comp_entity; - - OSMO_ASSERT(data); - OSMO_ASSERT(comp_entities); - - LOGP(DSNDCP, LOGL_DEBUG, - "Data compression entity list: comp_entities=%p\n", comp_entities); - - LOGP(DSNDCP, LOGL_DEBUG, "Data compression mode: dcomp=%d\n", pcomp); - - /* Skip on pcomp=0 */ - if (pcomp == 0) { - return len; - } - - /* Find out which compression entity handles the data */ - comp_entity = gprs_sndcp_comp_by_comp(comp_entities, pcomp); - - /* Skip compression if no suitable compression entity can be found */ - if (!comp_entity) { - return len; - } - - /* Note: Only data compression entities may appear in - * data compression context */ - OSMO_ASSERT(comp_entity->compclass == SNDCP_XID_DATA_COMPRESSION); - - /* Note: Currently V42BIS is the only compression method we - * support, so the only allowed algorithm is V42BIS */ - OSMO_ASSERT(comp_entity->algo == V42BIS); - - /* Find pcomp_index */ - pcomp_index = gprs_sndcp_comp_get_idx(comp_entity, pcomp); - - /* Run decompression algo */ - rc = v42bis_expand_unitdata(data, len, pcomp_index, comp_entity->state); - - LOGP(DSNDCP, LOGL_DEBUG, - "Data expansion done, old length=%d, new length=%d, entity=%p\n", - len, rc, comp_entity); - - return rc; -} - -/* 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) -{ - int rc; - uint8_t pcomp_index = 0; - struct gprs_sndcp_comp *comp_entity; - - OSMO_ASSERT(data); - OSMO_ASSERT(pcomp); - OSMO_ASSERT(comp_entities); - - LOGP(DSNDCP, LOGL_DEBUG, - "Data compression entity list: comp_entities=%p\n", comp_entities); - - /* Find out which compression entity handles the data */ - comp_entity = gprs_sndcp_comp_by_nsapi(comp_entities, nsapi); - - /* Skip compression if no suitable compression entity can be found */ - if (!comp_entity) { - *pcomp = 0; - return len; - } - - /* Note: Only data compression entities may appear in - * data compression context */ - OSMO_ASSERT(comp_entity->compclass == SNDCP_XID_DATA_COMPRESSION); - - /* Note: Currently V42BIS is the only compression method we - * support, so the only allowed algorithm is V42BIS */ - OSMO_ASSERT(comp_entity->algo == V42BIS); - - /* Run compression algo */ - rc = v42bis_compress_unitdata(&pcomp_index, data, len, - comp_entity->state); - - /* Find pcomp value */ - *pcomp = gprs_sndcp_comp_get_comp(comp_entity, pcomp_index); - - LOGP(DSNDCP, LOGL_DEBUG, "Data compression mode: dcomp=%d\n", *pcomp); - - LOGP(DSNDCP, LOGL_DEBUG, - "Data compression done, old length=%d, new length=%d, entity=%p\n", - len, rc, comp_entity); - - return rc; -} |