| /* |
| * Copyright (C) 2013 by Holger Hans Peter Freyther |
| * |
| * 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. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| */ |
| |
| #include "bts.h" |
| #include "gprs_debug.h" |
| #include <gprs_coding_scheme.h> |
| #include <rlc.h> |
| |
| #include <stdbool.h> |
| #include <string.h> |
| #include <sys/types.h> |
| |
| extern "C" { |
| #include <osmocom/core/utils.h> |
| #include <osmocom/core/bitvec.h> |
| #include <osmocom/core/logging.h> |
| } |
| |
| |
| uint8_t *gprs_rlc_data::prepare(size_t block_data_len) |
| { |
| /* todo.. only set it once if it turns out to be a bottleneck */ |
| memset(block, 0x0, sizeof(block)); |
| memset(block, 0x2b, block_data_len); |
| |
| /* Initial value of puncturing scheme */ |
| next_ps = EGPRS_PS_1; |
| |
| return block; |
| } |
| |
| void gprs_rlc_data::put_data(const uint8_t *data, size_t data_len) |
| { |
| memcpy(block, data, data_len); |
| len = data_len; |
| } |
| |
| void gprs_rlc_v_b::reset() |
| { |
| for (size_t i = 0; i < ARRAY_SIZE(m_v_b); ++i) |
| mark_invalid(i); |
| } |
| |
| void gprs_rlc_dl_window::reset() |
| { |
| m_v_s = 0; |
| m_v_a = 0; |
| m_v_b.reset(); |
| } |
| |
| int gprs_rlc_dl_window::resend_needed() const |
| { |
| for (uint16_t bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) { |
| if (m_v_b.is_nacked(bsn) || m_v_b.is_resend(bsn)) |
| return bsn; |
| } |
| |
| return -1; |
| } |
| |
| int gprs_rlc_dl_window::mark_for_resend() |
| { |
| int resend = 0; |
| |
| for (uint16_t bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) { |
| if (m_v_b.is_unacked(bsn)) { |
| /* mark to be re-send */ |
| m_v_b.mark_resend(bsn); |
| resend += 1; |
| } |
| } |
| |
| return resend; |
| } |
| |
| /* Update the receive block bitmap */ |
| uint16_t gprs_rlc_ul_window::update_egprs_rbb(uint8_t *rbb) |
| { |
| uint16_t i; |
| uint16_t bsn; |
| uint16_t bitmask = 0x80; |
| int8_t pos = 0; |
| int8_t bit_pos = 0; |
| for (i = 0, bsn = (v_q()+1); ((bsn < (v_r())) && (i < ws())); i++, |
| bsn = this->mod_sns(bsn + 1)) { |
| if (m_v_n.is_received(bsn)) { |
| rbb[pos] = rbb[pos] | bitmask; |
| } else { |
| rbb[pos] = rbb[pos] & (~bitmask); |
| } |
| bitmask = bitmask >> 1; |
| bit_pos++; |
| bit_pos = bit_pos % 8; |
| if (bit_pos == 0) { |
| pos++; |
| bitmask = 0x80; |
| } |
| } |
| return i; |
| } |
| |
| int gprs_rlc_dl_window::count_unacked() |
| { |
| uint16_t unacked = 0; |
| uint16_t bsn; |
| |
| for (bsn = v_a(); bsn != v_s(); bsn = mod_sns(bsn + 1)) { |
| if (!m_v_b.is_acked(bsn)) |
| unacked += 1; |
| } |
| |
| return unacked; |
| } |
| |
| static uint16_t bitnum_to_bsn(int bitnum, uint16_t ssn) |
| { |
| return (ssn - 1 - bitnum); |
| } |
| |
| void gprs_rlc_dl_window::update(BTS *bts, const struct bitvec *rbb, |
| uint16_t first_bsn, uint16_t *lost, |
| uint16_t *received) |
| { |
| unsigned dist = distance(); |
| unsigned num_blocks = rbb->cur_bit > dist |
| ? dist : rbb->cur_bit; |
| unsigned bsn; |
| |
| /* first_bsn is in range V(A)..V(S) */ |
| |
| for (unsigned int bitpos = 0; bitpos < num_blocks; bitpos++) { |
| bool is_ack; |
| bsn = mod_sns(first_bsn + bitpos); |
| if (bsn == mod_sns(v_a() - 1)) |
| break; |
| |
| is_ack = bitvec_get_bit_pos(rbb, bitpos) == 1; |
| |
| if (is_ack) { |
| LOGP(DRLCMACDL, LOGL_DEBUG, "- got ack for BSN=%d\n", bsn); |
| if (!m_v_b.is_acked(bsn)) |
| *received += 1; |
| m_v_b.mark_acked(bsn); |
| } else { |
| LOGP(DRLCMACDL, LOGL_DEBUG, "- got NACK for BSN=%d\n", bsn); |
| m_v_b.mark_nacked(bsn); |
| bts->rlc_nacked(); |
| *lost += 1; |
| } |
| } |
| } |
| |
| void gprs_rlc_dl_window::update(BTS *bts, char *show_rbb, uint16_t ssn, |
| uint16_t *lost, uint16_t *received) |
| { |
| /* SSN - 1 is in range V(A)..V(S)-1 */ |
| for (int bitpos = 0; bitpos < ws(); bitpos++) { |
| uint16_t bsn = mod_sns(bitnum_to_bsn(bitpos, ssn)); |
| |
| if (bsn == mod_sns(v_a() - 1)) |
| break; |
| |
| if (show_rbb[ws() - 1 - bitpos] == 'R') { |
| LOGP(DRLCMACDL, LOGL_DEBUG, "- got ack for BSN=%d\n", bsn); |
| if (!m_v_b.is_acked(bsn)) |
| *received += 1; |
| m_v_b.mark_acked(bsn); |
| } else { |
| LOGP(DRLCMACDL, LOGL_DEBUG, "- got NACK for BSN=%d\n", bsn); |
| m_v_b.mark_nacked(bsn); |
| bts->rlc_nacked(); |
| *lost += 1; |
| } |
| } |
| } |
| |
| int gprs_rlc_dl_window::move_window() |
| { |
| int i; |
| uint16_t bsn; |
| int moved = 0; |
| |
| for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = mod_sns(bsn + 1)) { |
| if (m_v_b.is_acked(bsn)) { |
| m_v_b.mark_invalid(bsn); |
| moved += 1; |
| } else |
| break; |
| } |
| |
| return moved; |
| } |
| |
| void gprs_rlc_dl_window::show_state(char *show_v_b) |
| { |
| int i; |
| uint16_t bsn; |
| |
| for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = mod_sns(bsn + 1)) { |
| uint16_t index = bsn & mod_sns_half(); |
| switch(m_v_b.get_state(index)) { |
| case GPRS_RLC_DL_BSN_INVALID: |
| show_v_b[i] = 'I'; |
| break; |
| case GPRS_RLC_DL_BSN_ACKED: |
| show_v_b[i] = 'A'; |
| break; |
| case GPRS_RLC_DL_BSN_RESEND: |
| show_v_b[i] = 'X'; |
| break; |
| case GPRS_RLC_DL_BSN_NACKED: |
| show_v_b[i] = 'N'; |
| break; |
| default: |
| show_v_b[i] = '?'; |
| } |
| } |
| show_v_b[i] = '\0'; |
| } |
| |
| void gprs_rlc_v_n::reset() |
| { |
| for (size_t i = 0; i < ARRAY_SIZE(m_v_n); ++i) |
| m_v_n[i] = GPRS_RLC_UL_BSN_INVALID; |
| } |
| |
| void gprs_rlc_window::set_sns(uint16_t sns) |
| { |
| OSMO_ASSERT(sns >= RLC_GPRS_SNS); |
| OSMO_ASSERT(sns <= RLC_MAX_SNS); |
| /* check for 2^n */ |
| OSMO_ASSERT((sns & (-sns)) == sns); |
| m_sns = sns; |
| } |
| |
| void gprs_rlc_window::set_ws(uint16_t ws) |
| { |
| LOGP(DRLCMAC, LOGL_INFO, "ws(%d)\n", |
| ws); |
| OSMO_ASSERT(ws >= RLC_GPRS_SNS/2); |
| OSMO_ASSERT(ws <= RLC_MAX_SNS/2); |
| m_ws = ws; |
| } |
| |
| /* Update the receive block bitmap */ |
| void gprs_rlc_ul_window::update_rbb(char *rbb) |
| { |
| int i; |
| for (i=0; i < ws(); i++) { |
| if (m_v_n.is_received((ssn()-1-i) & mod_sns())) |
| rbb[ws()-1-i] = 'R'; |
| else |
| rbb[ws()-1-i] = 'I'; |
| } |
| } |
| |
| /* Raise V(R) to highest received sequence number not received. */ |
| void gprs_rlc_ul_window::raise_v_r(const uint16_t bsn) |
| { |
| uint16_t offset_v_r; |
| offset_v_r = mod_sns(bsn + 1 - v_r()); |
| /* Positive offset, so raise. */ |
| if (offset_v_r < (sns() >> 1)) { |
| while (offset_v_r--) { |
| if (offset_v_r) /* all except the received block */ |
| m_v_n.mark_missing(v_r()); |
| raise_v_r_to(1); |
| } |
| LOGP(DRLCMACUL, LOGL_DEBUG, "- Raising V(R) to %d\n", v_r()); |
| } |
| } |
| |
| /* |
| * Raise V(Q) if possible. This is looped until there is a gap |
| * (non received block) or the window is empty. |
| */ |
| uint16_t gprs_rlc_ul_window::raise_v_q() |
| { |
| uint16_t count = 0; |
| |
| while (v_q() != v_r()) { |
| if (!m_v_n.is_received(v_q())) |
| break; |
| LOGP(DRLCMACUL, LOGL_DEBUG, "- Taking block %d out, raising " |
| "V(Q) to %d\n", v_q(), mod_sns(v_q() + 1)); |
| raise_v_q(1); |
| count += 1; |
| } |
| |
| return count; |
| } |
| |
| void gprs_rlc_ul_window::receive_bsn(const uint16_t bsn) |
| { |
| m_v_n.mark_received(bsn); |
| raise_v_r(bsn); |
| } |
| |
| bool gprs_rlc_ul_window::invalidate_bsn(const uint16_t bsn) |
| { |
| bool was_valid = m_v_n.is_received(bsn); |
| m_v_n.mark_missing(bsn); |
| |
| return was_valid; |
| } |
| |
| static void gprs_rlc_data_header_init(struct gprs_rlc_data_info *rlc, |
| GprsCodingScheme cs, bool with_padding, unsigned int header_bits, |
| const unsigned int spb) |
| { |
| unsigned int i; |
| unsigned int padding_bits = with_padding ? cs.optionalPaddingBits() : 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 = num_data_blocks(cs.headerTypeData()); |
| 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_rlc_data_block_info_init(&rlc->block_info[i], cs, |
| with_padding, spb); |
| |
| rlc->data_offs_bits[i] = |
| header_bits + padding_bits + |
| (i+1) * num_data_block_header_bits(cs.headerTypeData()) + |
| i * 8 * rlc->block_info[0].data_len; |
| } |
| } |
| |
| void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc, |
| GprsCodingScheme cs, bool with_padding, const unsigned int spb) |
| { |
| return gprs_rlc_data_header_init(rlc, cs, with_padding, |
| num_data_header_bits_DL(cs.headerTypeData()), spb); |
| } |
| |
| void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc, |
| GprsCodingScheme cs, bool with_padding) |
| { |
| /* |
| * last parameter is sent as 0 since common function used |
| * for both DL and UL |
| */ |
| return gprs_rlc_data_header_init(rlc, cs, with_padding, |
| num_data_header_bits_UL(cs.headerTypeData()), 0); |
| } |
| |
| void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi, |
| GprsCodingScheme cs, bool with_padding, const unsigned int spb) |
| { |
| unsigned int data_len = cs.maxDataBlockBytes(); |
| if (with_padding) |
| data_len -= cs.optionalPaddingBits() / 8; |
| |
| rdbi->data_len = data_len; |
| rdbi->bsn = 0; |
| rdbi->ti = 0; |
| rdbi->e = 1; |
| rdbi->cv = 15; |
| rdbi->pi = 0; |
| rdbi->spb = spb; |
| } |
| |
| unsigned int gprs_rlc_mcs_cps(GprsCodingScheme cs, |
| enum egprs_puncturing_values punct, |
| enum egprs_puncturing_values punct2, bool with_padding) |
| { |
| /* validate that punct and punct2 are as expected */ |
| switch (CodingScheme(cs)) { |
| case MCS9: |
| case MCS8: |
| case MCS7: |
| if (punct2 == EGPRS_PS_INVALID) { |
| LOGP(DRLCMACDL, LOGL_ERROR, |
| "Invalid punct2 value for coding scheme %d: %d\n", |
| CodingScheme(cs), punct2); |
| return -1; |
| } |
| /* fall through */ |
| case MCS6: |
| case MCS5: |
| case MCS4: |
| case MCS3: |
| case MCS2: |
| case MCS1: |
| if (punct == EGPRS_PS_INVALID) { |
| LOGP(DRLCMACDL, LOGL_ERROR, |
| "Invalid punct value for coding scheme %d: %d\n", |
| CodingScheme(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 (CodingScheme(cs)) { |
| case MCS1: return 0b1011 + |
| punct % EGPRS_MAX_PS_NUM_2; |
| case MCS2: return 0b1001 + |
| punct % EGPRS_MAX_PS_NUM_2; |
| case MCS3: return (with_padding ? 0b0110 : 0b0011) + |
| punct % EGPRS_MAX_PS_NUM_3; |
| case MCS4: return 0b0000 + |
| punct % EGPRS_MAX_PS_NUM_3; |
| case MCS5: return 0b100 + |
| punct % EGPRS_MAX_PS_NUM_2; |
| case MCS6: return (with_padding ? 0b010 : 0b000) + |
| punct % EGPRS_MAX_PS_NUM_2; |
| case MCS7: return 0b10100 + |
| 3 * (punct % EGPRS_MAX_PS_NUM_3) + |
| punct2 % EGPRS_MAX_PS_NUM_3; |
| case MCS8: return 0b01011 + |
| 3 * (punct % EGPRS_MAX_PS_NUM_3) + |
| punct2 % EGPRS_MAX_PS_NUM_3; |
| case MCS9: return 0b00000 + |
| 4 * (punct % EGPRS_MAX_PS_NUM_3) + |
| punct2 % EGPRS_MAX_PS_NUM_3; |
| default: ; |
| } |
| |
| return -1; |
| } |
| |
| void gprs_rlc_mcs_cps_decode(unsigned int cps, |
| GprsCodingScheme cs, int *punct, int *punct2, int *with_padding) |
| { |
| *punct2 = -1; |
| *with_padding = 0; |
| |
| switch (CodingScheme(cs)) { |
| case MCS1: |
| cps -= 0b1011; *punct = cps % 2; break; |
| case MCS2: |
| cps -= 0b1001; *punct = cps % 2; break; |
| case MCS3: |
| cps -= 0b0011; *punct = cps % 3; *with_padding = cps >= 3; break; |
| case MCS4: |
| cps -= 0b0000; *punct = cps % 3; break; |
| case MCS5: |
| cps -= 0b100; *punct = cps % 2; break; |
| case MCS6: |
| cps -= 0b000; *punct = cps % 2; *with_padding = cps >= 2; break; |
| case MCS7: |
| cps -= 0b10100; *punct = cps / 3; *punct2 = cps % 3; break; |
| case MCS8: |
| cps -= 0b01011; *punct = cps / 3; *punct2 = cps % 3; break; |
| case MCS9: |
| cps -= 0b00000; *punct = cps / 4; *punct2 = cps % 3; break; |
| default: ; |
| } |
| } |
| |
| /* |
| * Finds the PS value for retransmission with MCS change, |
| * retransmission with no MCS change, fresh transmission cases. |
| * The return value shall be used for current transmission only |
| * 44.060 9.3.2.1 defines the PS selection for MCS change case |
| * cs_current is the output of MCS selection algorithm for retx |
| * cs is coding scheme of previous transmission of RLC data block |
| */ |
| enum egprs_puncturing_values gprs_get_punct_scheme( |
| enum egprs_puncturing_values punct, |
| const GprsCodingScheme &cs, |
| const GprsCodingScheme &cs_current, |
| const enum egprs_rlcmac_dl_spb spb) |
| { |
| |
| /* |
| * 10.4.8b of TS 44.060 |
| * If it is second segment of the block |
| * dont change the puncturing scheme |
| */ |
| if (spb == EGPRS_RLCMAC_DL_SEC_SEG) |
| return punct; |
| |
| /* TS 44.060 9.3.2.1.1 */ |
| if ((CodingScheme(cs) == MCS9) && |
| (CodingScheme(cs_current) == MCS6)) { |
| if ((punct == EGPRS_PS_1) || (punct == EGPRS_PS_3)) |
| return EGPRS_PS_1; |
| else if (punct == EGPRS_PS_2) |
| return EGPRS_PS_2; |
| } else if ((CodingScheme(cs) == MCS6) && |
| (CodingScheme(cs_current) == MCS9)) { |
| if (punct == EGPRS_PS_1) |
| return EGPRS_PS_3; |
| else if (punct == EGPRS_PS_2) |
| return EGPRS_PS_2; |
| } else if ((CodingScheme(cs) == MCS7) && |
| (CodingScheme(cs_current) == MCS5)) |
| return EGPRS_PS_1; |
| else if ((CodingScheme(cs) == MCS5) && |
| (CodingScheme(cs_current) == MCS7)) |
| return EGPRS_PS_2; |
| else if (cs != cs_current) |
| return 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 EGPRS_PS_INVALID; |
| } |
| |
| /* |
| * This function calculates puncturing scheme for retransmission of a RLC |
| * block with same MCS. The computed value shall be used for next transmission |
| * of the same RLC block |
| * TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1 |
| */ |
| void gprs_update_punct_scheme(enum egprs_puncturing_values *punct, |
| const GprsCodingScheme &cs) |
| { |
| switch (CodingScheme(cs)) { |
| case MCS1 : |
| case MCS2 : |
| case MCS5 : |
| case MCS6 : |
| *punct = ((enum egprs_puncturing_values)((*punct + 1) % |
| EGPRS_MAX_PS_NUM_2)); |
| break; |
| case MCS3 : |
| case MCS4 : |
| case MCS7 : |
| case MCS8 : |
| case MCS9 : |
| *punct = ((enum egprs_puncturing_values)((*punct + 1) % |
| EGPRS_MAX_PS_NUM_3)); |
| break; |
| default: |
| break; |
| } |
| } |