/* rlc header descriptions * * Copyright (C) 2012 Ivan Klyuchnikov * Copyright (C) 2012 Andreas Eversberg * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * 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 General Public License for more details. */ #pragma once #ifdef __cplusplus extern "C" { #endif #include "coding_scheme.h" #include #ifdef __cplusplus } #endif #include #include #define RLC_GPRS_SNS 128 /* GPRS, must be power of 2 */ #define RLC_EGPRS_SNS 2048 /* EGPRS, must be power of 2 */ #define RLC_MAX_SNS RLC_EGPRS_SNS #define RLC_MAX_LEN 74 /* MCS-9 data unit */ /* * EGPRS resegment status information for UL * When only first split block is received bsn state * will be set to EGPRS_RESEG_FIRST_SEG_RXD and when * only second segment is received the state will be * set to EGPRS_RESEG_SECOND_SEG_RXD. When both Split * blocks are received the state will be set to * EGPRS_RESEG_DEFAULT * The EGPRS resegmentation feature allows MS to retransmit * RLC blocks of HeaderType1, HeaderType2 by segmenting * them to 2 HeaderType3 blocks(Example MCS5 will be * retransmitted as 2 MCS2 blocks). Table 10.4.8b.1 of 44.060 * explains the possible values of SPB in HeadrType3 for UL * direction. When the MCS is changed at the PCU, PCU directs the * changed MCS to MS by PUAN or UPLINK ASSIGNMENT message along * with RESEGMENT flag, Then MS may decide to retransmit the * blocks by resegmenting it based on Table 8.1.1.1 of 44.060. * The retransmission MCS is calculated based on current MCS of * the Block and demanded MCS by PCU. Section 10.3a.4.3 of 44.060 * shows the HeadrType3 with SPB field present in it */ enum egprs_rlc_ul_reseg_bsn_state { EGPRS_RESEG_DEFAULT = 0, EGPRS_RESEG_FIRST_SEG_RXD = 0x01, EGPRS_RESEG_SECOND_SEG_RXD = 0x02, EGPRS_RESEG_INVALID = 0x04 }; /* * EGPRS resegment status information for DL * When only first segment is sent, bsn state * will be set to EGPRS_RESEG_FIRST_SEG_SENT and when * second segment is sent the state will be * set to EGPRS_RESEG_SECOND_SEG_SENT. * EGPRS_RESEG_DL_INVALID is set to 8 considering there is a scope for * 3rd segment according to Table 10.4.8b.2 of 44.060 * The EGPRS resegmentation feature allows PCU to retransmit * RLC blocks of HeaderType1, HeaderType2 by segmenting * them to 2 HeaderType3 blocks(Example MCS5 will be * retransmitted as 2 MCS2 blocks). Table 10.4.8b.2 of 44.060 * explains the possible values of SPB in HeadrType3 for DL * direction.The PCU decides to retransmit the * blocks by resegmenting it based on Table 8.1.1.1 of 44.060. * The retransmission MCS is calculated based on current MCS of * the Block and demanded MCS by PCU. Section 10.3a.3.3 of 44.060 * shows the HeadrType3 with SPB field present in it */ enum egprs_rlc_dl_reseg_bsn_state { EGPRS_RESEG_DL_DEFAULT = 0, EGPRS_RESEG_FIRST_SEG_SENT = 0x01, EGPRS_RESEG_SECOND_SEG_SENT = 0x02, EGPRS_RESEG_DL_INVALID = 0x08 }; /* Table 10.4.8b.2 of 44.060 */ enum egprs_rlcmac_dl_spb { EGPRS_RLCMAC_DL_NO_RETX = 0, EGPRS_RLCMAC_DL_FIRST_SEG = 2, EGPRS_RLCMAC_DL_SEC_SEG = 3, }; /* * Valid puncturing scheme values * TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1 */ enum egprs_puncturing_values { EGPRS_PS_1, EGPRS_PS_2, EGPRS_PS_3, EGPRS_PS_INVALID, }; /* * EGPRS_MAX_PS_NUM_2 is valid for MCS 1,2,5,6. * And EGPRS_MAX_PS_NUM_3 is valid for MCS 3,4,7,8,9 * TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1 */ enum egprs_puncturing_types { EGPRS_MAX_PS_NUM_2 = 2, EGPRS_MAX_PS_NUM_3, EGPRS_MAX_PS_NUM_INVALID, }; static inline uint16_t mod_sns_half() { return (RLC_MAX_SNS / 2) - 1; } struct gprs_rlc_data_block_info { unsigned int data_len; /* EGPRS: N2, GPRS: N2-2, N-2 */ unsigned int bsn; unsigned int ti; unsigned int e; unsigned int cv; /* FBI == 1 <=> CV == 0 */ unsigned int pi; unsigned int spb; }; struct gprs_rlc_data_info { enum CodingScheme cs; unsigned int r; unsigned int si; unsigned int tfi; unsigned int cps; unsigned int rsb; unsigned int usf; unsigned int es_p; unsigned int rrbp; unsigned int pr; uint8_t num_data_blocks; /* this can actually be only 0, 1, 2: enforced in gprs_rlc_data_header_init() */ unsigned int with_padding; unsigned int data_offs_bits[2]; struct gprs_rlc_data_block_info block_info[2]; }; /* holds the current status of the block w.r.t UL/DL split blocks */ union split_block_status { egprs_rlc_ul_reseg_bsn_state block_status_ul; egprs_rlc_dl_reseg_bsn_state block_status_dl; }; struct gprs_rlc_data { /* block data including LI headers */ uint8_t block[RLC_MAX_LEN]; /* block data len including LI headers*/ uint8_t len; struct gprs_rlc_data_block_info block_info; /* * cs_current_trans is variable to hold the cs_last value for * current transmission. cs_current_trans is same as cs_last during * transmission case. during retransmission cs_current_trans is * fetched from egprs_mcs_retx_tbl table based on * cs and demanded cs.reference is 44.060 Table * 8.1.1.1 and Table 8.1.1.2 * For UL. cs_last shall be used everywhere. */ enum CodingScheme cs_current_trans; enum CodingScheme cs_last; /* * The MCS of initial transmission of a BSN * This variable is used for split block * processing in DL */ enum CodingScheme cs_init; /* puncturing scheme value to be used for next transmission*/ enum egprs_puncturing_values next_ps; /* holds the status of the block w.r.t UL/DL split blocks*/ union split_block_status spb_status; }; uint8_t *prepare(struct gprs_rlc_data *rlc, size_t block_data_length); void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc, enum CodingScheme cs, bool with_padding, const unsigned int spb); void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc, enum CodingScheme cs, bool with_padding); void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi, enum CodingScheme cs, bool with_padding, const unsigned int spb); unsigned int gprs_rlc_mcs_cps(enum CodingScheme cs, enum egprs_puncturing_values punct, enum egprs_puncturing_values punct2, bool with_padding); void gprs_rlc_mcs_cps_decode(unsigned int cps, enum CodingScheme cs, int *punct, int *punct2, int *with_padding); enum egprs_puncturing_values gprs_get_punct_scheme(enum egprs_puncturing_values punct, const enum CodingScheme &cs, const enum CodingScheme &cs_current_trans, const enum egprs_rlcmac_dl_spb spb); void gprs_update_punct_scheme(enum egprs_puncturing_values *punct, const enum CodingScheme &cs); /* * I hold the currently transferred blocks and will provide * the routines to manipulate these arrays. */ struct gprs_rlc { void init(); gprs_rlc_data *block(int bsn); gprs_rlc_data m_blocks[RLC_MAX_SNS/2]; }; extern "C" { /* TS 44.060 10.2.2 */ struct rlc_ul_header { #if OSMO_IS_LITTLE_ENDIAN uint8_t r:1, si:1, cv:4, pt:2; uint8_t ti:1, tfi:5, pi:1, spare:1; uint8_t e:1, bsn:7; #elif OSMO_IS_BIG_ENDIAN /* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */ uint8_t pt:2, cv:4, si:1, r:1; uint8_t spare:1, pi:1, tfi:5, ti:1; uint8_t bsn:7, e:1; #endif } __attribute__ ((packed)); struct rlc_dl_header { #if OSMO_IS_LITTLE_ENDIAN uint8_t usf:3, s_p:1, rrbp:2, pt:2; uint8_t fbi:1, tfi:5, pr:2; uint8_t e:1, bsn:7; #elif OSMO_IS_BIG_ENDIAN /* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */ uint8_t pt:2, rrbp:2, s_p:1, usf:3; uint8_t pr:2, tfi:5, fbi:1; uint8_t bsn:7, e:1; #endif } __attribute__ ((packed)); struct rlc_li_field { #if OSMO_IS_LITTLE_ENDIAN uint8_t e:1, m:1, li:6; #elif OSMO_IS_BIG_ENDIAN /* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */ uint8_t li:6, m:1, e:1; #endif } __attribute__ ((packed)); struct rlc_li_field_egprs { #if OSMO_IS_LITTLE_ENDIAN uint8_t e:1, li:7; #elif OSMO_IS_BIG_ENDIAN /* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */ uint8_t li:7, e:1; #endif } __attribute__ ((packed)); } inline void gprs_rlc::init() { memset(m_blocks, 0, sizeof(m_blocks)); } inline gprs_rlc_data *gprs_rlc::block(int bsn) { return &m_blocks[bsn & mod_sns_half()]; }