Add Header Type2 support in EGPRS UL

This patch will add support for MCS5,6 in EGPRS UL along with incorrect
assert correction to let MCS 6 work.

Change-Id: Iac2422c8acbdcefe20aafbba6a4eb87c9893e3ba
Reviewed-on: https://gerrit.osmocom.org/269
Tested-by: Jenkins Builder
Reviewed-by: Harald Welte <laforge@gnumonks.org>

3 files changed, 54 insertions, 4 deletions

diff --git a/src/decoding.cpp b/src/decoding.cpp
index 26008797..e1f8134c 100644
--- a/src/decoding.cpp
+++ b/src/decoding.cpp
@@ -353,9 +353,11 @@ int Decoding::rlc_parse_ul_data_header(struct gprs_rlc_data_info *rlc,
 	case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_3 :
 		cur_bit = rlc_parse_ul_data_header_egprs_type_3(rlc, data, cs);
 		break;
-	case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_1:
-	case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_2:
-		/* TODO: Support both header types */
+	case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_2 :
+		cur_bit = rlc_parse_ul_data_header_egprs_type_2(rlc, data, cs);
+		break;
+	case GprsCodingScheme::HEADER_EGPRS_DATA_TYPE_1 :
+		/* TODO: Support both header type 1 */
 		/* fall through */
 	default:
 		LOGP(DRLCMACDL, LOGL_ERROR,
@@ -409,6 +411,50 @@ int Decoding::rlc_parse_ul_data_header_egprs_type_3(
 	return cur_bit;
 }
 
+int Decoding::rlc_parse_ul_data_header_egprs_type_2(
+	struct gprs_rlc_data_info *rlc,
+	const uint8_t *data,
+	const GprsCodingScheme &cs)
+{
+	const struct gprs_rlc_ul_header_egprs_2 *egprs2;
+	unsigned int e_ti_header, offs, cur_bit = 0;
+	int punct, punct2, with_padding, cps;
+
+	egprs2 = static_cast < struct gprs_rlc_ul_header_egprs_2 * >
+			((void *)data);
+
+	cps    = (egprs2->cps_a << 0)  | (egprs2->cps_b << 2);
+	gprs_rlc_mcs_cps_decode(cps, cs, &punct, &punct2, &with_padding);
+	gprs_rlc_data_info_init_ul(rlc, cs, with_padding);
+
+	rlc->r      = egprs2->r;
+	rlc->si     = egprs2->si;
+	rlc->tfi    = (egprs2->tfi_a << 0)  | (egprs2->tfi_b << 2);
+	rlc->cps    = cps;
+	rlc->rsb    = egprs2->rsb;
+
+	rlc->num_data_blocks = 1;
+	rlc->block_info[0].cv  = egprs2->cv;
+	rlc->block_info[0].pi  = egprs2->pi;
+	rlc->block_info[0].bsn =
+		(egprs2->bsn1_a << 0) | (egprs2->bsn1_b << 5);
+
+	cur_bit += rlc->data_offs_bits[0] - 2;
+
+	offs = rlc->data_offs_bits[0] / 8;
+	OSMO_ASSERT(rlc->data_offs_bits[0] % 8 == 7);
+
+	e_ti_header = (data[offs] & 0x60) >> 5;
+	rlc->block_info[0].e   = !!(e_ti_header & 0x01);
+	rlc->block_info[0].ti  = !!(e_ti_header & 0x02);
+	cur_bit += 2;
+
+	/* skip data area */
+	cur_bit += cs.maxDataBlockBytes() * 8;
+
+	return cur_bit;
+}
+
 int Decoding::rlc_parse_ul_data_header_gprs(struct gprs_rlc_data_info *rlc,
 	const uint8_t *data, const GprsCodingScheme &cs)
 {
diff --git a/src/decoding.h b/src/decoding.h
index 50c9e7d3..736adf10 100644
--- a/src/decoding.h
+++ b/src/decoding.h
@@ -48,6 +48,10 @@ public:
 		struct gprs_rlc_data_info *rlc,
 		const uint8_t *data,
 		const GprsCodingScheme &cs);
+	static int rlc_parse_ul_data_header_egprs_type_2(
+		struct gprs_rlc_data_info *rlc,
+		const uint8_t *data,
+		const GprsCodingScheme &cs);
 	static int rlc_parse_ul_data_header_gprs(
 		struct gprs_rlc_data_info *rlc,
 		const uint8_t *data,
diff --git a/src/tbf_ul.cpp b/src/tbf_ul.cpp
index 98962d17..4d283a9a 100644
--- a/src/tbf_ul.cpp
+++ b/src/tbf_ul.cpp
@@ -225,7 +225,7 @@ int gprs_rlcmac_ul_tbf::rcv_data_block_acknowledged(
 		block = m_rlc.block(rdbi->bsn);
 		block->block_info = *rdbi;
 		block->cs = rlc->cs;
-		OSMO_ASSERT(rdbi->data_len < sizeof(block->block));
+		OSMO_ASSERT(rdbi->data_len <= sizeof(block->block));
 		rlc_data = &(block->block[0]);
 		/* TODO: Handle SPB != 0 -> Set length to 2*len, add offset if
 		 * 2nd part. Note that resegmentation is currently disabled