edge: Add methods for unified GPRS/EGPRS UL data block handling

The current rcv_data_block_acknowledged_gprs method is tightly
coupled to GPRS.

This commit adds variants of the involved methods that support
EGPRS and GPRS RLC encodings likewise.

Sponsored-by: On-Waves ehf

3 files changed, 275 insertions, 2 deletions

diff --git a/src/rlc.h b/src/rlc.h
index bc93c2d4..f2acb98a 100644
--- a/src/rlc.h
+++ b/src/rlc.h
@@ -86,6 +86,7 @@ struct gprs_rlc_data {
 	/* block len of history */
 	uint8_t len;
 
+	struct gprs_rlc_ul_data_block_info block_info;
 	GprsCodingScheme cs;
 };
 
diff --git a/src/tbf.h b/src/tbf.h
index 252e9d52..b00dd0f3 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -424,8 +424,13 @@ struct gprs_rlcmac_ul_tbf : public gprs_rlcmac_tbf {
 	/* blocks were acked */
 	int rcv_data_block_acknowledged_gprs(const uint8_t *data, size_t len,
 		struct pcu_l1_meas *meas);
+	int rcv_data_block_acknowledged(
+		const struct gprs_rlc_ul_header_egprs *rlc,
+		uint8_t *data, uint8_t len, struct pcu_l1_meas *meas);
+
 
 	/* TODO: extract LLC class? */
+	int assemble_forward_llc_gprs(const gprs_rlc_data *data);
 	int assemble_forward_llc(const gprs_rlc_data *data);
 	int snd_ul_ud();
 
@@ -443,6 +448,7 @@ struct gprs_rlcmac_ul_tbf : public gprs_rlcmac_tbf {
 
 protected:
 	void maybe_schedule_uplink_acknack(const rlc_ul_header *rh);
+	void maybe_schedule_uplink_acknack(const gprs_rlc_ul_header_egprs *rlc);
 };
 
 inline enum gprs_rlcmac_tbf_direction reverse(enum gprs_rlcmac_tbf_direction dir)
diff --git a/src/tbf_ul.cpp b/src/tbf_ul.cpp
index 4a5f21f5..f2cd4771 100644
--- a/src/tbf_ul.cpp
+++ b/src/tbf_ul.cpp
@@ -47,7 +47,7 @@ extern void *tall_pcu_ctx;
  * Store received block data in LLC message(s) and forward to SGSN
  * if complete.
  */
-int gprs_rlcmac_ul_tbf::assemble_forward_llc(const gprs_rlc_data *_data)
+int gprs_rlcmac_ul_tbf::assemble_forward_llc_gprs(const gprs_rlc_data *_data)
 {
 	const uint8_t *data = _data->block;
 	uint8_t len = _data->len;
@@ -209,6 +209,50 @@ int gprs_rlcmac_ul_tbf::assemble_forward_llc(const gprs_rlc_data *_data)
 	return 0;
 }
 
+/*
+ * Store received block data in LLC message(s) and forward to SGSN
+ * if complete.
+ */
+int gprs_rlcmac_ul_tbf::assemble_forward_llc(const gprs_rlc_data *_data)
+{
+	const uint8_t *data = _data->block;
+	uint8_t len = _data->len;
+	const struct gprs_rlc_ul_data_block_info *rdbi = &_data->block_info;
+	GprsCodingScheme cs = _data->cs;
+
+	Decoding::RlcData frames[16], *frame;
+	int i, num_frames = 0;
+	uint32_t dummy_tlli;
+
+	LOGP(DRLCMACUL, LOGL_DEBUG, "- Assembling frames: (len=%d)\n", len);
+
+	num_frames = Decoding::rlc_data_from_ul_data(
+		rdbi, cs, data, &(frames[0]), sizeof(frames),
+		&dummy_tlli);
+
+	/* create LLC frames */
+	for (i = 0; i < num_frames; i++) {
+		frame = frames + i;
+
+		LOGP(DRLCMACUL, LOGL_DEBUG, "-- Frame %d starts at offset %d, "
+			"length=%d, is_complete=%d\n",
+			i + 1, frame->offset, frame->length, frame->is_complete);
+
+		m_llc.append_frame(data + frame->offset, frame->length);
+		m_llc.consume(frame->length);
+
+		if (frame->is_complete) {
+			/* send frame to SGSN */
+			LOGP(DRLCMACUL, LOGL_INFO, "%s complete UL frame len=%d\n",
+				tbf_name(this) , m_llc.frame_length());
+			snd_ul_ud();
+			m_llc.reset();
+		}
+	}
+
+	return 0;
+}
+
 
 struct msgb *gprs_rlcmac_ul_tbf::create_ul_ack(uint32_t fn)
 {
@@ -262,6 +306,191 @@ struct msgb *gprs_rlcmac_ul_tbf::create_ul_ack(uint32_t fn)
 	return msg;
 }
 
+int gprs_rlcmac_ul_tbf::rcv_data_block_acknowledged(
+	const struct gprs_rlc_ul_header_egprs *rlc,
+	uint8_t *data, uint8_t len, struct pcu_l1_meas *meas)
+{
+	int8_t rssi = meas->have_rssi ? meas->rssi : 0;
+
+	const uint16_t mod_sns = m_window.mod_sns();
+	const uint16_t ws = m_window.ws();
+
+	this->state_flags |= (1 << GPRS_RLCMAC_FLAG_UL_DATA);
+
+	LOGP(DRLCMACUL, LOGL_DEBUG, "UL DATA TFI=%d received (V(Q)=%d .. "
+		"V(R)=%d)\n", rlc->tfi, this->m_window.v_q(),
+		this->m_window.v_r());
+
+	/* process RSSI */
+	gprs_rlcmac_rssi(this, rssi);
+
+	/* store measurement values */
+	if (ms())
+		ms()->update_l1_meas(meas);
+
+	uint32_t new_tlli = 0;
+	unsigned int block_idx;
+
+	/* restart T3169 */
+	tbf_timer_start(this, 3169, bts_data()->t3169, 0);
+
+	/* Increment RX-counter */
+	this->m_rx_counter++;
+
+	/* Loop over num_blocks */
+	for (block_idx = 0; block_idx < rlc->num_data_blocks; block_idx++) {
+		int num_chunks;
+		uint8_t *rlc_data;
+		const struct gprs_rlc_ul_data_block_info *rdbi =
+			&rlc->block_info[block_idx];
+		bool need_rlc_data = false;
+		struct gprs_rlc_data *block;
+
+		LOGP(DRLCMACUL, LOGL_DEBUG,
+			"%s: Got %s RLC data block: "
+			"CV=%d, BSN=%d, SPB=%d, "
+			"PI=%d, E=%d, TI=%d, bitoffs=%d\n",
+			name(), rlc->cs.name(),
+			rdbi->cv, rdbi->bsn, rdbi->spb,
+			rdbi->pi, rdbi->e, rdbi->ti,
+			rlc->data_offs_bits[block_idx]);
+
+		/* Check whether the block needs to be decoded */
+
+		if (!m_window.is_in_window(rdbi->bsn)) {
+			LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d out of window "
+				"%d..%d (it's normal)\n", rdbi->bsn,
+				m_window.v_q(),
+				(m_window.v_q() + ws - 1) & mod_sns);
+		} else if (m_window.is_received(rdbi->bsn)) {
+			LOGP(DRLCMACUL, LOGL_DEBUG,
+				"- BSN %d already received\n", rdbi->bsn);
+		} else {
+			need_rlc_data = true;
+		}
+
+		if (!is_tlli_valid()) {
+			if (!rdbi->ti) {
+				LOGP(DRLCMACUL, LOGL_NOTICE,
+					"%s: Missing TLLI within UL DATA.\n",
+					name());
+				continue;
+			}
+			need_rlc_data = true;
+		}
+
+		if (!need_rlc_data)
+			continue;
+
+		/* Store block and meta info to BSN buffer */
+
+		LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d storing in window (%d..%d)\n",
+			rdbi->bsn, m_window.v_q(),
+			(m_window.v_q() + ws - 1) & mod_sns);
+		block = m_rlc.block(rdbi->bsn);
+		block->block_info = *rdbi;
+		block->cs = rlc->cs;
+		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
+		 * within the UL assignment.
+		 */
+		if (rdbi->spb) {
+			LOGP(DRLCMACUL, LOGL_NOTICE,
+				"Got SPB != 0 but resegmentation has been "
+				"disabled, skipping %s data block with BSN %d, "
+				"TFI=%d.\n", rlc->cs.name(), rdbi->bsn,
+				rlc->tfi);
+			continue;
+		}
+
+		block->len =
+			Decoding::rlc_copy_to_aligned_buffer(rlc, block_idx, data,
+				rlc_data);
+
+
+		/* TODO: Handle SPB != 0 -> set state to partly received
+		 * (upper/lower) and continue with the loop, unless the other
+		 * part is already present.
+		 */
+
+		/* Get/Handle TLLI */
+		if (rdbi->ti) {
+			num_chunks = Decoding::rlc_data_from_ul_data(
+				rdbi, rlc->cs, rlc_data, NULL, 0, &new_tlli);
+
+			if (num_chunks < 0) {
+				bts->decode_error();
+				LOGP(DRLCMACUL, LOGL_NOTICE,
+					"Failed to decode TLLI of %s UL DATA "
+					"TFI=%d.\n", rlc->cs.name(), rlc->tfi);
+				m_window.invalidate_bsn(rdbi->bsn);
+				continue;
+			}
+			if (!this->is_tlli_valid()) {
+				if (!new_tlli) {
+					LOGP(DRLCMACUL, LOGL_NOTICE,
+						"%s: TLLI = 0 within UL DATA.\n",
+						name());
+					m_window.invalidate_bsn(rdbi->bsn);
+					continue;
+				}
+				LOGP(DRLCMACUL, LOGL_INFO,
+					"Decoded premier TLLI=0x%08x of "
+					"UL DATA TFI=%d.\n", tlli(), rlc->tfi);
+				set_tlli_from_ul(new_tlli);
+			} else if (new_tlli && new_tlli != tlli()) {
+				LOGP(DRLCMACUL, LOGL_NOTICE, "TLLI mismatch on UL "
+					"DATA TFI=%d. (Ignoring due to contention "
+					"resolution)\n", rlc->tfi);
+				m_window.invalidate_bsn(rdbi->bsn);
+				continue;
+			}
+		}
+
+		m_window.receive_bsn(rdbi->bsn);
+	}
+
+	/* Raise V(Q) if possible, and retrieve LLC frames from blocks.
+	 * This is looped until there is a gap (non received block) or
+	 * the window is empty.*/
+	const uint16_t v_q_beg = m_window.v_q();
+	const uint16_t count = m_window.raise_v_q();
+
+	/* Retrieve LLC frames from blocks that are ready */
+	for (uint16_t i = 0; i < count; ++i) {
+		uint16_t index = (v_q_beg + i) & mod_sns;
+		assemble_forward_llc(m_rlc.block(index));
+	}
+
+	/* Check CV of last frame in buffer */
+	if (this->state_is(GPRS_RLCMAC_FLOW) /* still in flow state */
+	 && this->m_window.v_q() == this->m_window.v_r()) { /* if complete */
+		struct gprs_rlc_data *block =
+			m_rlc.block((m_window.v_r() - 1) & mod_sns);
+		const struct gprs_rlc_ul_data_block_info *rdbi =
+			&block->block_info;
+
+		LOGP(DRLCMACUL, LOGL_DEBUG, "- No gaps in received block, "
+			"last block: BSN=%d CV=%d\n", rdbi->bsn,
+			rdbi->cv);
+		if (rdbi->cv == 0) {
+			LOGP(DRLCMACUL, LOGL_DEBUG, "- Finished with UL "
+				"TBF\n");
+			set_state(GPRS_RLCMAC_FINISHED);
+			/* Reset N3103 counter. */
+			this->m_n3103 = 0;
+		}
+	}
+
+	/* If TLLI is included or if we received half of the window, we send
+	 * an ack/nack */
+	maybe_schedule_uplink_acknack(rlc);
+
+	return 0;
+}
+
 int gprs_rlcmac_ul_tbf::rcv_data_block_acknowledged_gprs(const uint8_t *data,
 	size_t len, struct pcu_l1_meas *meas)
 {
@@ -338,7 +567,7 @@ int gprs_rlcmac_ul_tbf::rcv_data_block_acknowledged_gprs(const uint8_t *data,
 	/* Retrieve LLC frames from blocks that are ready */
 	for (uint16_t i = 0; i < count; ++i) {
 		uint16_t index = (v_q_beg + i) & mod_sns;
-		assemble_forward_llc(m_rlc.block(index));
+		assemble_forward_llc_gprs(m_rlc.block(index));
 	}
 
 	/* Check CV of last frame in buffer */
@@ -365,6 +594,43 @@ int gprs_rlcmac_ul_tbf::rcv_data_block_acknowledged_gprs(const uint8_t *data,
 	return 0;
 }
 
+void gprs_rlcmac_ul_tbf::maybe_schedule_uplink_acknack(
+	const gprs_rlc_ul_header_egprs *rlc)
+{
+	bool have_ti = rlc->block_info[0].ti ||
+		(rlc->num_data_blocks > 1 && rlc->block_info[1].ti);
+
+	if (rlc->si || have_ti || state_is(GPRS_RLCMAC_FINISHED) ||
+		(m_rx_counter % SEND_ACK_AFTER_FRAMES) == 0)
+	{
+		if (rlc->si) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "- Scheduling Ack/Nack, "
+				"because MS is stalled.\n");
+		}
+		if (have_ti) {
+			LOGP(DRLCMACUL, LOGL_DEBUG, "- Scheduling Ack/Nack, "
+				"because TLLI is included.\n");
+		}
+		if (state_is(GPRS_RLCMAC_FINISHED)) {
+			LOGP(DRLCMACUL, LOGL_DEBUG, "- Scheduling Ack/Nack, "
+				"because last block has CV==0.\n");
+		}
+		if ((m_rx_counter % SEND_ACK_AFTER_FRAMES) == 0) {
+			LOGP(DRLCMACUL, LOGL_DEBUG, "- Scheduling Ack/Nack, "
+				"because %d frames received.\n",
+				SEND_ACK_AFTER_FRAMES);
+		}
+		if (ul_ack_state == GPRS_RLCMAC_UL_ACK_NONE) {
+			/* trigger sending at next RTS */
+			ul_ack_state = GPRS_RLCMAC_UL_ACK_SEND_ACK;
+		} else {
+			/* already triggered */
+			LOGP(DRLCMACUL, LOGL_DEBUG, "-  Sending Ack/Nack is "
+				"already triggered, don't schedule!\n");
+		}
+	}
+}
+
 void gprs_rlcmac_ul_tbf::maybe_schedule_uplink_acknack(const rlc_ul_header *rh)
 {
 	if (rh->si || rh->ti || state_is(GPRS_RLCMAC_FINISHED)