290 lines
8.5 KiB
C
290 lines
8.5 KiB
C
/* rlc header descriptions
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*
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* Copyright (C) 2012 Ivan Klyuchnikov
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* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#pragma once
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "coding_scheme.h"
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#include <osmocom/core/endian.h>
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#ifdef __cplusplus
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}
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#endif
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#include <stdint.h>
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#include <string.h>
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#define RLC_GPRS_SNS 128 /* GPRS, must be power of 2 */
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#define RLC_EGPRS_SNS 2048 /* EGPRS, must be power of 2 */
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#define RLC_MAX_SNS RLC_EGPRS_SNS
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#define RLC_MAX_LEN 74 /* MCS-9 data unit */
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/*
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* EGPRS resegment status information for UL
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* When only first split block is received bsn state
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* will be set to EGPRS_RESEG_FIRST_SEG_RXD and when
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* only second segment is received the state will be
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* set to EGPRS_RESEG_SECOND_SEG_RXD. When both Split
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* blocks are received the state will be set to
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* EGPRS_RESEG_DEFAULT
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* The EGPRS resegmentation feature allows MS to retransmit
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* RLC blocks of HeaderType1, HeaderType2 by segmenting
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* them to 2 HeaderType3 blocks(Example MCS5 will be
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* retransmitted as 2 MCS2 blocks). Table 10.4.8b.1 of 44.060
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* explains the possible values of SPB in HeadrType3 for UL
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* direction. When the MCS is changed at the PCU, PCU directs the
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* changed MCS to MS by PUAN or UPLINK ASSIGNMENT message along
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* with RESEGMENT flag, Then MS may decide to retransmit the
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* blocks by resegmenting it based on Table 8.1.1.1 of 44.060.
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* The retransmission MCS is calculated based on current MCS of
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* the Block and demanded MCS by PCU. Section 10.3a.4.3 of 44.060
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* shows the HeadrType3 with SPB field present in it
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*/
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enum egprs_rlc_ul_reseg_bsn_state {
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EGPRS_RESEG_DEFAULT = 0,
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EGPRS_RESEG_FIRST_SEG_RXD = 0x01,
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EGPRS_RESEG_SECOND_SEG_RXD = 0x02,
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EGPRS_RESEG_INVALID = 0x04
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};
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/*
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* EGPRS resegment status information for DL
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* When only first segment is sent, bsn state
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* will be set to EGPRS_RESEG_FIRST_SEG_SENT and when
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* second segment is sent the state will be
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* set to EGPRS_RESEG_SECOND_SEG_SENT.
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* EGPRS_RESEG_DL_INVALID is set to 8 considering there is a scope for
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* 3rd segment according to Table 10.4.8b.2 of 44.060
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* The EGPRS resegmentation feature allows PCU to retransmit
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* RLC blocks of HeaderType1, HeaderType2 by segmenting
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* them to 2 HeaderType3 blocks(Example MCS5 will be
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* retransmitted as 2 MCS2 blocks). Table 10.4.8b.2 of 44.060
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* explains the possible values of SPB in HeadrType3 for DL
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* direction.The PCU decides to retransmit the
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* blocks by resegmenting it based on Table 8.1.1.1 of 44.060.
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* The retransmission MCS is calculated based on current MCS of
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* the Block and demanded MCS by PCU. Section 10.3a.3.3 of 44.060
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* shows the HeadrType3 with SPB field present in it
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*/
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enum egprs_rlc_dl_reseg_bsn_state {
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EGPRS_RESEG_DL_DEFAULT = 0,
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EGPRS_RESEG_FIRST_SEG_SENT = 0x01,
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EGPRS_RESEG_SECOND_SEG_SENT = 0x02,
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EGPRS_RESEG_DL_INVALID = 0x08
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};
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/* Table 10.4.8b.2 of 44.060 */
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enum egprs_rlcmac_dl_spb {
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EGPRS_RLCMAC_DL_NO_RETX = 0,
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EGPRS_RLCMAC_DL_FIRST_SEG = 2,
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EGPRS_RLCMAC_DL_SEC_SEG = 3,
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};
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/*
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* Valid puncturing scheme values
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* TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1
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*/
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enum egprs_puncturing_values {
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EGPRS_PS_1,
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EGPRS_PS_2,
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EGPRS_PS_3,
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EGPRS_PS_INVALID,
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};
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/*
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* EGPRS_MAX_PS_NUM_2 is valid for MCS 1,2,5,6.
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* And EGPRS_MAX_PS_NUM_3 is valid for MCS 3,4,7,8,9
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* TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1
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*/
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enum egprs_puncturing_types {
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EGPRS_MAX_PS_NUM_2 = 2,
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EGPRS_MAX_PS_NUM_3,
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EGPRS_MAX_PS_NUM_INVALID,
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};
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static inline uint16_t mod_sns_half()
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{
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return (RLC_MAX_SNS / 2) - 1;
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}
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struct gprs_rlc_data_block_info {
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unsigned int data_len; /* EGPRS: N2, GPRS: N2-2, N-2 */
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unsigned int bsn;
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unsigned int ti;
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unsigned int e;
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unsigned int cv; /* FBI == 1 <=> CV == 0 */
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unsigned int pi;
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unsigned int spb;
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};
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struct gprs_rlc_data_info {
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enum CodingScheme cs;
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unsigned int r;
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unsigned int si;
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unsigned int tfi;
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unsigned int cps;
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unsigned int rsb;
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unsigned int usf;
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unsigned int es_p;
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unsigned int rrbp;
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unsigned int pr;
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uint8_t num_data_blocks; /* this can actually be only 0, 1, 2: enforced in gprs_rlc_data_header_init() */
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unsigned int with_padding;
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unsigned int data_offs_bits[2];
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struct gprs_rlc_data_block_info block_info[2];
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};
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/* holds the current status of the block w.r.t UL/DL split blocks */
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union split_block_status {
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egprs_rlc_ul_reseg_bsn_state block_status_ul;
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egprs_rlc_dl_reseg_bsn_state block_status_dl;
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};
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struct gprs_rlc_data {
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/* block data including LI headers */
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uint8_t block[RLC_MAX_LEN];
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/* block data len including LI headers*/
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uint8_t len;
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struct gprs_rlc_data_block_info block_info;
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/*
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* cs_current_trans is variable to hold the cs_last value for
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* current transmission. cs_current_trans is same as cs_last during
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* transmission case. during retransmission cs_current_trans is
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* fetched from egprs_mcs_retx_tbl table based on
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* cs and demanded cs.reference is 44.060 Table
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* 8.1.1.1 and Table 8.1.1.2
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* For UL. cs_last shall be used everywhere.
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*/
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enum CodingScheme cs_current_trans;
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enum CodingScheme cs_last;
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/*
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* The MCS of initial transmission of a BSN
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* This variable is used for split block
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* processing in DL
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*/
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enum CodingScheme cs_init;
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/* puncturing scheme value to be used for next transmission*/
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enum egprs_puncturing_values next_ps;
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/* holds the status of the block w.r.t UL/DL split blocks*/
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union split_block_status spb_status;
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};
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uint8_t *prepare(struct gprs_rlc_data *rlc, size_t block_data_length);
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void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc,
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enum CodingScheme cs, bool with_padding, const unsigned int spb);
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void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc,
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enum CodingScheme cs, bool with_padding);
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void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi,
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enum CodingScheme cs, bool with_padding, const unsigned int spb);
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unsigned int gprs_rlc_mcs_cps(enum CodingScheme cs, enum egprs_puncturing_values
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punct, enum egprs_puncturing_values punct2, bool with_padding);
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void gprs_rlc_mcs_cps_decode(unsigned int cps, enum CodingScheme cs,
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int *punct, int *punct2, int *with_padding);
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enum egprs_puncturing_values gprs_get_punct_scheme(enum egprs_puncturing_values
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punct, const enum CodingScheme &cs,
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const enum CodingScheme &cs_current_trans,
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const enum egprs_rlcmac_dl_spb spb);
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void gprs_update_punct_scheme(enum egprs_puncturing_values *punct,
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const enum CodingScheme &cs);
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/*
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* I hold the currently transferred blocks and will provide
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* the routines to manipulate these arrays.
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*/
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struct gprs_rlc {
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void init();
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gprs_rlc_data *block(int bsn);
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gprs_rlc_data m_blocks[RLC_MAX_SNS/2];
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};
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extern "C" {
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/* TS 44.060 10.2.2 */
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struct rlc_ul_header {
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#if OSMO_IS_LITTLE_ENDIAN
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uint8_t r:1,
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si:1,
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cv:4,
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pt:2;
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uint8_t ti:1,
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tfi:5,
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pi:1,
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spare:1;
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uint8_t e:1,
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bsn:7;
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#elif OSMO_IS_BIG_ENDIAN
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/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */
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uint8_t pt:2, cv:4, si:1, r:1;
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uint8_t spare:1, pi:1, tfi:5, ti:1;
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uint8_t bsn:7, e:1;
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#endif
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} __attribute__ ((packed));
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struct rlc_dl_header {
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#if OSMO_IS_LITTLE_ENDIAN
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uint8_t usf:3,
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s_p:1,
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rrbp:2,
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pt:2;
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uint8_t fbi:1,
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tfi:5,
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pr:2;
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uint8_t e:1,
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bsn:7;
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#elif OSMO_IS_BIG_ENDIAN
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/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */
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uint8_t pt:2, rrbp:2, s_p:1, usf:3;
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uint8_t pr:2, tfi:5, fbi:1;
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uint8_t bsn:7, e:1;
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#endif
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} __attribute__ ((packed));
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struct rlc_li_field {
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#if OSMO_IS_LITTLE_ENDIAN
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uint8_t e:1,
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m:1,
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li:6;
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#elif OSMO_IS_BIG_ENDIAN
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/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */
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uint8_t li:6, m:1, e:1;
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#endif
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} __attribute__ ((packed));
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struct rlc_li_field_egprs {
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#if OSMO_IS_LITTLE_ENDIAN
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uint8_t e:1,
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li:7;
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#elif OSMO_IS_BIG_ENDIAN
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/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */
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uint8_t li:7, e:1;
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#endif
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} __attribute__ ((packed));
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}
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inline void gprs_rlc::init()
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{
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memset(m_blocks, 0, sizeof(m_blocks));
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}
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inline gprs_rlc_data *gprs_rlc::block(int bsn)
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{
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return &m_blocks[bsn & mod_sns_half()];
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}
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