diff options
Diffstat (limited to 'src/encoding.cpp')
| -rw-r--r-- | src/encoding.cpp | 145 |
1 files changed, 112 insertions, 33 deletions
diff --git a/src/encoding.cpp b/src/encoding.cpp index 2648b027..e7e13ac1 100644 --- a/src/encoding.cpp +++ b/src/encoding.cpp @@ -35,7 +35,72 @@ extern "C" { #include <errno.h> #include <string.h> +#define CHECK(rc) { if (rc < 0) return rc; } +#define SET_X(bv, x) { if (bitvec_set_bit(bv, x) < 0) return -EOWNERDEAD; } +#define SET_0(bv) SET_X(bv, ZERO) +#define SET_1(bv) SET_X(bv, ONE) +#define SET_L(bv) SET_X(bv, L) +#define SET_H(bv) SET_X(bv, H) + +/* 3GPP TS 44.018 § 10.5.2.16: + { 0 | 1 < ALPHA : bit (4) > } + < GAMMA : bit (5) > +*/ +static int write_alpha_gamma(bitvec *dest, uint8_t alpha, uint8_t gamma) +{ + int rc; + + if (alpha) { + SET_1(dest); + rc = bitvec_set_u64(dest, alpha, 4, false); + CHECK(rc); + } else + SET_0(dest); + + rc = bitvec_set_u64(dest, gamma, 5, false); + CHECK(rc); + + return 0; +} + +/* TBF_STARTING_TIME -- same as 3GPP TS 44.018 §10.5.2.38 Starting Time without tag: */ +static int write_tbf_start_time(bitvec *dest, uint32_t fn) +{ + int rc; + + /* Set values according to 3GPP TS 44.018 Table 10.5.2.38.1 */ + + /* T1' */ + rc = bitvec_set_u64(dest, (fn / (26 * 51)) % 32, 5, false); + CHECK(rc); + + /* T3 */ + rc = bitvec_set_u64(dest, fn % 51, 6, false); + CHECK(rc); + + /* T2 */ + rc = bitvec_set_u64(dest, fn % 26, 5, false); + CHECK(rc); + + return rc; +} + /* { 0 | 1 < TIMING_ADVANCE_INDEX : bit (4) > } */ +static 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: */ @@ -88,43 +153,55 @@ static inline void write_ta_ie(bitvec *dest, unsigned& wp, } static 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, unsigned& wp) + uint32_t fn, uint8_t alpha, uint8_t gamma, int8_t ta_idx) { int rc = 0; - 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); + 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); + 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 (polling) { - 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); + SET_1(dest); + rc = write_tbf_start_time(dest, fn); + CHECK(rc); + } else + SET_0(dest); + + SET_0(dest); /* No P0 nor PR_MODE */ + if (tbf->is_egprs_enabled()) { - 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 - } + 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 */ return rc; } @@ -393,8 +470,10 @@ int Encoding::write_immediate_assignment( 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, wp); + ta_idx); } else if (((burst_type == GSM_L1_BURST_TYPE_ACCESS_1) || (burst_type == GSM_L1_BURST_TYPE_ACCESS_2))) { bitvec_write_field(dest, &wp, 1, 2); /* LH */ bitvec_write_field(dest, &wp, 0, 2); /* 0 EGPRS Uplink Assignment */ |