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authorNeels Hofmeyr <neels@hofmeyr.de>2018-02-27 22:41:07 +0100
committerNeels Hofmeyr <neels@hofmeyr.de>2018-02-27 22:43:32 +0100
commit17b92f315d45b943c8b8903c3911f8fd25768ddf (patch)
treebf8431b66e980dbc2730465c3c20f0b8666f8043
parentb56c00197d8dfaaeaee96b8817a15e3fd4b0e085 (diff)
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
-rw-r--r--src/encoding.cpp121
1 files changed, 48 insertions, 73 deletions
diff --git a/src/encoding.cpp b/src/encoding.cpp
index 279bbfe..7b711b8 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);