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libosmo-gprs/src/rlcmac/rlc.c

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/* RLC block management as per 3GPP TS 44.060 */
/*
* (C) 2012 Ivan Klyuchnikov
* (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
* (C) 2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
*
* All Rights Reserved
*
* 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.
*/
#include <osmocom/core/utils.h>
#include <osmocom/core/logging.h>
#include <osmocom/gprs/rlcmac/rlc.h>
#include <osmocom/gprs/rlcmac/rlcmac_private.h>
void gprs_rlcmac_rlc_block_info_init(struct gprs_rlcmac_rlc_block_info *rdbi,
enum gprs_rlcmac_coding_scheme cs,
bool with_padding, unsigned int spb)
{
unsigned int data_len = gprs_rlcmac_mcs_max_data_block_bytes(cs);
if (with_padding)
data_len -= gprs_rlcmac_mcs_opt_padding_bits(cs) / 8;
rdbi->data_len = data_len;
rdbi->bsn = 0;
rdbi->ti = 0;
rdbi->e = 1;
rdbi->cv = 15;
rdbi->pi = 0;
rdbi->spb = spb;
}
static void gprs_rlcmac_rlc_data_header_init(struct gprs_rlcmac_rlc_data_info *rlc,
enum gprs_rlcmac_coding_scheme cs,
bool with_padding, unsigned int header_bits,
unsigned int spb)
{
unsigned int i;
unsigned int padding_bits = with_padding ? gprs_rlcmac_mcs_opt_padding_bits(cs) : 0;
rlc->cs = cs;
rlc->r = 0;
rlc->si = 0;
rlc->tfi = 0;
rlc->cps = 0;
rlc->rsb = 0;
rlc->usf = 0;
rlc->es_p = 0;
rlc->rrbp = 0;
rlc->pr = 0;
rlc->num_data_blocks = gprs_rlcmac_num_data_blocks(gprs_rlcmac_mcs_header_type(cs));
rlc->with_padding = with_padding;
OSMO_ASSERT(rlc->num_data_blocks <= ARRAY_SIZE(rlc->block_info));
for (i = 0; i < rlc->num_data_blocks; i++) {
gprs_rlcmac_rlc_block_info_init(&rlc->block_info[i], cs, with_padding, spb);
rlc->data_offs_bits[i] =
header_bits + padding_bits +
(i+1) * gprs_rlcmac_num_data_block_header_bits(gprs_rlcmac_mcs_header_type(cs)) +
i * 8 * rlc->block_info[0].data_len;
}
}
void gprs_rlcmac_rlc_data_info_init_ul(struct gprs_rlcmac_rlc_data_info *rlc,
enum gprs_rlcmac_coding_scheme cs,
bool with_padding, unsigned int spb)
{
OSMO_ASSERT(gprs_rlcmac_mcs_is_valid(cs));
return gprs_rlcmac_rlc_data_header_init(
rlc, cs, with_padding,
gprs_rlcmac_num_data_header_bits_UL(gprs_rlcmac_mcs_header_type(cs)), spb);
}
void gprs_rlcmac_rlc_data_info_init_dl(struct gprs_rlcmac_rlc_data_info *rlc,
enum gprs_rlcmac_coding_scheme cs,
bool with_padding)
{
OSMO_ASSERT(gprs_rlcmac_mcs_is_valid(cs));
/*
* last parameter is sent as 0 since common function used
* for both DL and UL
*/
return gprs_rlcmac_rlc_data_header_init(
rlc, cs, with_padding,
gprs_rlcmac_num_data_header_bits_DL(gprs_rlcmac_mcs_header_type(cs)), 0);
}
uint8_t *gprs_rlcmac_rlc_block_prepare(struct gprs_rlcmac_rlc_block *blk, size_t block_data_len)
{
/* todo.. only set it once if it turns out to be a bottleneck */
memset(blk->buf, 0x0, sizeof(blk->buf));
memset(blk->buf, 0x2b, block_data_len);
/* Initial value of puncturing scheme */
blk->next_ps = GPRS_RLCMAC_EGPRS_PS_1;
return blk->buf;
}
struct gprs_rlcmac_rlc_block_store *gprs_rlcmac_rlc_block_store_alloc(void *ctx)
{
struct gprs_rlcmac_rlc_block_store *blkst;
blkst = talloc_zero(ctx, struct gprs_rlcmac_rlc_block_store);
if (!blkst)
return NULL;
return blkst;
}
void gprs_rlcmac_rlc_block_store_free(struct gprs_rlcmac_rlc_block_store *blkst)
{
talloc_free(blkst);
}
struct gprs_rlcmac_rlc_block *gprs_rlcmac_rlc_block_store_get_block(struct gprs_rlcmac_rlc_block_store *blkst, int bsn)
{
return &blkst->blocks[bsn & mod_sns_half()];
}
unsigned int gprs_rlcmac_rlc_mcs_cps(enum gprs_rlcmac_coding_scheme cs,
enum gprs_rlcmac_egprs_puncturing_values punct,
enum gprs_rlcmac_egprs_puncturing_values punct2,
bool with_padding)
{
/* validate that punct and punct2 are as expected */
switch (cs) {
case GPRS_RLCMAC_MCS_9:
case GPRS_RLCMAC_MCS_8:
case GPRS_RLCMAC_MCS_7:
if (punct2 == GPRS_RLCMAC_EGPRS_PS_INVALID) {
LOGRLCMAC(LOGL_ERROR, "Invalid punct2 value for coding scheme %d: %d\n",
cs, punct2);
return -1;
}
/* fall through */
case GPRS_RLCMAC_MCS_6:
case GPRS_RLCMAC_MCS_5:
case GPRS_RLCMAC_MCS_4:
case GPRS_RLCMAC_MCS_3:
case GPRS_RLCMAC_MCS_2:
case GPRS_RLCMAC_MCS_1:
if (punct == GPRS_RLCMAC_EGPRS_PS_INVALID) {
LOGRLCMAC(LOGL_ERROR, "Invalid punct value for coding scheme %d: %d\n",
cs, punct);
return -1;
}
break;
default:
return -1;
}
/* See 3GPP TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1 */
switch (cs) {
case GPRS_RLCMAC_MCS_1:
return 0b1011 +
punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_2;
case GPRS_RLCMAC_MCS_2:
return 0b1001 +
punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_2;
case GPRS_RLCMAC_MCS_3:
return (with_padding ? 0b0110 : 0b0011) +
punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3;
case GPRS_RLCMAC_MCS_4:
return 0b0000 +
punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3;
case GPRS_RLCMAC_MCS_5:
return 0b100 +
punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_2;
case GPRS_RLCMAC_MCS_6:
return (with_padding ? 0b010 : 0b000) +
punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_2;
case GPRS_RLCMAC_MCS_7:
return 0b10100 +
3 * (punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3) +
punct2 % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3;
case GPRS_RLCMAC_MCS_8:
return 0b01011 +
3 * (punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3) +
punct2 % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3;
case GPRS_RLCMAC_MCS_9:
return 0b00000 +
4 * (punct % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3) +
punct2 % GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3;
default:
break;
}
return -1;
}
enum gprs_rlcmac_egprs_puncturing_values
gprs_rlcmac_get_punct_scheme(enum gprs_rlcmac_egprs_puncturing_values punct,
enum gprs_rlcmac_coding_scheme cs,
enum gprs_rlcmac_coding_scheme cs_current,
enum gprs_rlcmac_rlc_egprs_ul_spb spb)
{
/*
* 10.4.8b of TS 44.060
* If it is second segment of the block
* dont change the puncturing scheme
*/
if (spb == GPRS_RLCMAC_EGPRS_UL_SPB_SEC_SEG)
return punct;
/* TS 44.060 9.3.2.1.1 */
if ((cs == GPRS_RLCMAC_MCS_9) &&
(cs_current == GPRS_RLCMAC_MCS_6)) {
if ((punct == GPRS_RLCMAC_EGPRS_PS_1) || (punct == GPRS_RLCMAC_EGPRS_PS_3))
return GPRS_RLCMAC_EGPRS_PS_1;
else if (punct == GPRS_RLCMAC_EGPRS_PS_2)
return GPRS_RLCMAC_EGPRS_PS_2;
} else if ((cs == GPRS_RLCMAC_MCS_6) &&
(cs_current == GPRS_RLCMAC_MCS_9)) {
if (punct == GPRS_RLCMAC_EGPRS_PS_1)
return GPRS_RLCMAC_EGPRS_PS_3;
else if (punct == GPRS_RLCMAC_EGPRS_PS_2)
return GPRS_RLCMAC_EGPRS_PS_2;
} else if ((cs == GPRS_RLCMAC_MCS_7) &&
(cs_current == GPRS_RLCMAC_MCS_5))
return GPRS_RLCMAC_EGPRS_PS_1;
else if ((cs == GPRS_RLCMAC_MCS_5) &&
(cs_current == GPRS_RLCMAC_MCS_7))
return GPRS_RLCMAC_EGPRS_PS_2;
else if (cs != cs_current)
return GPRS_RLCMAC_EGPRS_PS_1;
/* TS 44.060 9.3.2.1.1 ends here */
/*
* Below else will handle fresh transmission, retransmission with no
* MCS change case
*/
else
return punct;
return GPRS_RLCMAC_EGPRS_PS_INVALID;
}
void gprs_rlcmac_update_punct_scheme(enum gprs_rlcmac_egprs_puncturing_values *punct, enum gprs_rlcmac_coding_scheme cs)
{
switch (cs) {
case GPRS_RLCMAC_MCS_1:
case GPRS_RLCMAC_MCS_2:
case GPRS_RLCMAC_MCS_5:
case GPRS_RLCMAC_MCS_6:
*punct = ((enum gprs_rlcmac_egprs_puncturing_values)((*punct + 1) %
GPRS_RLCMAC_EGPRS_MAX_PS_NUM_2));
break;
case GPRS_RLCMAC_MCS_3:
case GPRS_RLCMAC_MCS_4:
case GPRS_RLCMAC_MCS_7:
case GPRS_RLCMAC_MCS_8:
case GPRS_RLCMAC_MCS_9:
*punct = ((enum gprs_rlcmac_egprs_puncturing_values)((*punct + 1) %
GPRS_RLCMAC_EGPRS_MAX_PS_NUM_3));
break;
default:
break;
}
}
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