From 17b92f315d45b943c8b8903c3911f8fd25768ddf Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Tue, 27 Feb 2018 22:41:07 +0100 Subject: Revert "Rewrite Packet Downlink Assignment" This reverts commit 896574e92bea09ed8d39688b6fdf504e84521746, I52ec9b07413daabba8cd5f1fba5c7b3af6a33389. This commit was found (empirically) to be a regression, rendering GPRS service fatally unreliable. Related: OS#3013 Change-Id: Idcba0381f70eb7f7c9aefdee9dfeafd5de96a9be --- src/encoding.cpp | 121 ++++++++++++++++++++++--------------------------------- 1 file changed, 48 insertions(+), 73 deletions(-) diff --git a/src/encoding.cpp b/src/encoding.cpp index 279bbfe8..7b711b81 100644 --- a/src/encoding.cpp +++ b/src/encoding.cpp @@ -44,21 +44,6 @@ extern "C" { #define set_H(bv) set_x(bv, H) /* { 0 | 1 < TIMING_ADVANCE_INDEX : bit (4) > } */ -static inline int write_ta_index(bitvec *dest, int8_t tai) -{ - int rc; - - if (tai < 0) /* No TIMING_ADVANCE_INDEX: */ - set_0(dest); - - /* TIMING_ADVANCE_INDEX: */ - set_1(dest); - rc = bitvec_set_u64(dest, tai, 4, false); - check(rc); - - return 0; -} - static inline bool write_tai(bitvec *dest, unsigned& wp, int8_t tai) { if (tai < 0) { /* No TIMING_ADVANCE_INDEX: */ @@ -174,58 +159,52 @@ static inline int write_tfi_usf(bitvec *dest, const gprs_rlcmac_ul_tbf *tbf, uin return 0; } -/* 3GPP TS 44.018 ยง10.5.2.16 IA Rest Octets ::= Packet Downlink Assignment */ -static inline int write_ia_rest_downlink(const gprs_rlcmac_dl_tbf *tbf, bitvec *dest, - bool polling, bool ta_valid, uint32_t fn, - uint8_t alpha, uint8_t gamma, int8_t ta_idx) +static int write_ia_rest_downlink( + gprs_rlcmac_dl_tbf *tbf, + bitvec * dest, unsigned& wp, + uint8_t polling, bool ta_valid, uint32_t fn, + uint8_t alpha, uint8_t gamma, int8_t ta_idx) { - int rc; - - set_H(dest); set_H(dest); - set_0(dest); set_1(dest); /* 00 Packet Downlink Assignment */ - - rc = bitvec_set_u64(dest, tbf->tlli(), 32, false); /* TLLI */ - check(rc); - - set_1(dest); - rc = bitvec_set_u64(dest, tbf->tfi(), 5, false); /* TFI_ASSIGNMENT */ - check(rc); - - /* RLC acknowledged mode */ - set_0(dest); /* RLC_MODE */ - - rc = write_alpha_gamma(dest, alpha, gamma); /* ALPHA and GAMMA */ - check(rc); - - rc = bitvec_set_bit(dest, (bit_value)polling); /* POLLING */ - check(rc); - - /* N. B: NOT related to TAI! */ - rc = bitvec_set_bit(dest, (bit_value)ta_valid); /* TA_VALID */ - check(rc); - - rc = write_ta_index(dest, ta_idx); - check(rc); - + if (!tbf) { + LOGP(DRLCMACDL, LOGL_ERROR, + "Cannot encode DL IMMEDIATE ASSIGNMENT without TBF\n"); + return -EINVAL; + } + // GSM 04.08 10.5.2.16 IA Rest Octets + bitvec_write_field(dest, &wp, 3, 2); // "HH" + bitvec_write_field(dest, &wp, 1, 2); // "01" Packet Downlink Assignment + bitvec_write_field(dest, &wp,tbf->tlli(),32); // TLLI + bitvec_write_field(dest, &wp,0x1,1); // switch TFI : on + bitvec_write_field(dest, &wp,tbf->tfi(),5); // TFI + bitvec_write_field(dest, &wp,0x0,1); // RLC acknowledged mode + if (alpha) { + bitvec_write_field(dest, &wp,0x1,1); // ALPHA = present + bitvec_write_field(dest, &wp,alpha,4); // ALPHA + } else { + bitvec_write_field(dest, &wp,0x0,1); // ALPHA = not present + } + bitvec_write_field(dest, &wp,gamma,5); // GAMMA power control parameter + bitvec_write_field(dest, &wp,polling,1); // Polling Bit + bitvec_write_field(dest, &wp, ta_valid, 1); // N. B: NOT related to TAI! + write_tai(dest, wp, ta_idx); if (polling) { - set_1(dest); - rc = write_tbf_start_time(dest, fn); /* TBF_STARTING_TIME */ - check(rc); - } else - set_0(dest); /* No TBF_STARTING_TIME */ - - set_0(dest); /* No P0 nor PR_MODE */ - + bitvec_write_field(dest, &wp,0x1,1); // TBF Starting TIME present + bitvec_write_field(dest, &wp,(fn / (26 * 51)) % 32,5); // T1' + bitvec_write_field(dest, &wp,fn % 51,6); // T3 + bitvec_write_field(dest, &wp,fn % 26,5); // T2 + } else { + bitvec_write_field(dest, &wp,0x0,1); // TBF Starting TIME present + } + bitvec_write_field(dest, &wp,0x0,1); // P0 not present + // bitvec_write_field(dest, &wp,0x1,1); // P0 not present + // bitvec_write_field(dest, &wp,,0xb,4); if (tbf->is_egprs_enabled()) { - set_H(dest); - rc = bitvec_set_u64(dest, enc_ws(tbf->window_size()), 5, false); /* EGPRS Window Size */ - check(rc); - - /* The mobile station shall not report measurements: (see 3GPP TS 44.060 Table 11.2.7.1) */ - set_0(dest); set_0(dest); /* LINK_QUALITY_MEASUREMENT_MODE */ - set_1(dest); /* No BEP_PERIOD2 */ - } else - set_L(dest); /* No Additions for Rel-6 */ + /* see GMS 44.018, 10.5.2.16 */ + bitvec_write_field(dest, &wp, 1, 1); // "H" + write_ws(dest, &wp, tbf->window_size()); // EGPRS Window Size + bitvec_write_field(dest, &wp, 0x0, 2); // LINK_QUALITY_MEASUREMENT_MODE + bitvec_write_field(dest, &wp, 0, 1); // BEP_PERIOD2 not present + } return 0; } @@ -481,15 +460,11 @@ int Encoding::write_immediate_assignment( plen = wp / 8; - if (downlink) { - if (!as_dl_tbf(tbf)) { - LOGP(DRLCMACDL, LOGL_ERROR, "Cannot encode DL IMMEDIATE ASSIGNMENT without TBF\n"); - return -EINVAL; - } - dest->cur_bit = wp; - rc = write_ia_rest_downlink(as_dl_tbf(tbf), dest, polling, gsm48_ta_is_valid(ta), fn, - alpha, gamma, ta_idx); - } else if (((burst_type == GSM_L1_BURST_TYPE_ACCESS_1) || + if (downlink) + rc = write_ia_rest_downlink(as_dl_tbf(tbf), dest, wp, + polling, gsm48_ta_is_valid(ta), fn, + alpha, gamma, ta_idx); + else if (((burst_type == GSM_L1_BURST_TYPE_ACCESS_1) || (burst_type == GSM_L1_BURST_TYPE_ACCESS_2))) { dest->cur_bit = wp; rc = write_ia_rest_egprs_uplink(as_ul_tbf(tbf), dest, usf, fn, alpha, gamma, ta_idx, burst_type, ra); -- cgit v1.2.3