tbf: Split out UL/DL TBF methods into separate files

tbf_ul.cpp for UL TBF methods
tbf_dl.cpp for DL TBF methods

This commit contains no code changes.

Ticket: SYS#389
Sponsored by: On-Waves ehf

1 files changed, 418 insertions, 0 deletions

diff --git a/src/tbf_ul.cpp b/src/tbf_ul.cpp
new file mode 100644
index 00000000..3ab71f05
--- /dev/null
+++ b/src/tbf_ul.cpp
@@ -0,0 +1,418 @@
+/* Copied from tbf.cpp
+ *
+ * Copyright (C) 2012 Ivan Klyuchnikov
+ * Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
+ * Copyright (C) 2013 by Holger Hans Peter Freyther
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#include <bts.h>
+#include <tbf.h>
+#include <rlc.h>
+#include <encoding.h>
+#include <gprs_rlcmac.h>
+#include <gprs_debug.h>
+#include <gprs_bssgp_pcu.h>
+#include <decoding.h>
+
+extern "C" {
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/talloc.h>
+}
+
+#include <errno.h>
+#include <string.h>
+
+/* After receiving these frames, we send ack/nack. */
+#define SEND_ACK_AFTER_FRAMES 20
+
+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)
+{
+	const uint8_t *data = _data->block;
+	uint8_t len = _data->len;
+	const struct rlc_ul_header *rh = (const struct rlc_ul_header *) data;
+	uint8_t e, m;
+	struct rlc_li_field *li;
+	uint8_t frame_offset[16], offset = 0, chunk;
+	int i, frames = 0;
+
+	LOGP(DRLCMACUL, LOGL_DEBUG, "- Assembling frames: (len=%d)\n", len);
+
+	data += 3;
+	len -= 3;
+	e = rh->e; /* if extended */
+	m = 1; /* more frames, that means: the first frame */
+
+	/* Parse frame offsets from length indicator(s), if any. */
+	while (1) {
+		if (frames == (int)sizeof(frame_offset)) {
+			LOGP(DRLCMACUL, LOGL_ERROR, "%s too many frames in "
+				"block\n", tbf_name(this));
+			return -EINVAL;
+		}
+		frame_offset[frames++] = offset;
+		LOGP(DRLCMACUL, LOGL_DEBUG, "-- Frame %d starts at offset "
+			"%d\n", frames, offset);
+		if (!len)
+			break;
+		/* M == 0 and E == 0 is not allowed in this version. */
+		if (!m && !e) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "%s UL DATA "
+				"ignored, because M='0' and E='0'.\n",
+				tbf_name(this));
+			return 0;
+		}
+		/* no more frames in this segment */
+		if (e) {
+			break;
+		}
+		/* There is a new frame and an LI that delimits it. */
+		if (m) {
+			li = (struct rlc_li_field *)data;
+			LOGP(DRLCMACUL, LOGL_DEBUG, "-- Delimiter len=%d\n",
+				li->li);
+			/* Special case: LI == 0
+			 * If the last segment would fit precisely into the
+			 * rest of the RLC MAC block, there would be no way
+			 * to delimit that this segment ends and is not
+			 * continued in the next block.
+			 * The special LI (0) is used to force the segment to
+			 * extend into the next block, so it is delimited there.
+			 * This LI must be skipped. Also it is the last LI.
+			 */
+			if (li->li == 0) {
+				data++;
+				len--;
+				m = 1; /* M is ignored, we know there is more */
+				break; /* handle E as '1', so we break! */
+			}
+			e = li->e;
+			m = li->m;
+			offset += li->li;
+			data++;
+			len--;
+			continue;
+		}
+	}
+	if (!m) {
+		LOGP(DRLCMACUL, LOGL_DEBUG, "- Last frame carries spare "
+			"data\n");
+	}
+
+	LOGP(DRLCMACUL, LOGL_DEBUG, "- Data length after length fields: %d\n",
+		len);
+	/* TLLI */
+	if (rh->ti) {
+		if (len < 4) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "%s UL DATA TLLI out of "
+				"frame border\n", tbf_name(this));
+			return -EINVAL;
+		}
+		data += 4;
+		len -= 4;
+		LOGP(DRLCMACUL, LOGL_DEBUG, "- Length after skipping TLLI: "
+			"%d\n", len);
+	}
+
+	/* PFI */
+	if (rh->pi) {
+		LOGP(DRLCMACUL, LOGL_ERROR, "ERROR: PFI not supported, "
+			"please disable in SYSTEM INFORMATION\n");
+		if (len < 1) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "%s UL DATA PFI out of "
+				"frame border\n", tbf_name(this));
+			return -EINVAL;
+		}
+		data++;
+		len--;
+		LOGP(DRLCMACUL, LOGL_DEBUG, "- Length after skipping PFI: "
+			"%d\n", len);
+	}
+
+	/* Now we have:
+	 * - a list of frames offsets: frame_offset[]
+	 * - number of frames: i
+	 * - m == 0: Last frame carries spare data (end of TBF).
+	 */
+
+	/* Check if last offset would exceed frame. */
+	if (offset > len) {
+		LOGP(DRLCMACUL, LOGL_NOTICE, "%s UL DATA ignored, "
+			"because LI delimits data that exceeds block size.\n",
+			tbf_name(this));
+		return -EINVAL;
+	}
+
+	/* create LLC frames */
+	for (i = 0; i < frames; i++) {
+		/* last frame ? */
+		if (i == frames - 1) {
+			/* no more data in last frame */
+			if (!m)
+				break;
+			/* data until end of frame */
+			chunk = len - frame_offset[i];
+		} else {
+			/* data until next frame */
+			chunk = frame_offset[i + 1] - frame_offset[i];
+		}
+		if (!m_llc.fits_in_current_frame(chunk)) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "%s LLC frame exceeds "
+				"maximum size %u.\n", tbf_name(this),
+				m_llc.remaining_space());
+			chunk = m_llc.remaining_space();
+		}
+		m_llc.append_frame(data + frame_offset[i], chunk);
+		m_llc.consume(chunk);
+		/* not last frame. */
+		if (i != frames - 1) {
+			/* 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();
+		/* also check if CV==0, because the frame may fill up the
+		 * block precisely, then it is also complete. normally the
+		 * frame would be extended into the next block with a 0-length
+		 * delimiter added to this block. */
+		} else if (rh->cv == 0) {
+			/* send frame to SGSN */
+			LOGP(DRLCMACUL, LOGL_INFO, "%s complete UL frame "
+				"that fits precisely in last block: "
+				"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)
+{
+	int final = (state_is(GPRS_RLCMAC_FINISHED));
+	struct msgb *msg;
+
+	if (final) {
+		if (poll_state != GPRS_RLCMAC_POLL_NONE) {
+			LOGP(DRLCMACUL, LOGL_DEBUG, "Polling is already "
+				"sheduled for %s, so we must wait for "
+				"final uplink ack...\n", tbf_name(this));
+			return NULL;
+		}
+		if (bts->sba()->find(trx->trx_no, control_ts, (fn + 13) % 2715648)) {
+			LOGP(DRLCMACUL, LOGL_DEBUG, "Polling is already "
+				"scheduled for single block allocation...\n");
+			return NULL;
+		}
+	}
+
+	msg = msgb_alloc(23, "rlcmac_ul_ack");
+	if (!msg)
+		return NULL;
+	bitvec *ack_vec = bitvec_alloc(23);
+	if (!ack_vec) {
+		msgb_free(msg);
+		return NULL;
+	}
+	bitvec_unhex(ack_vec,
+		"2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
+	RlcMacDownlink_t * mac_control_block = (RlcMacDownlink_t *)talloc_zero(tall_pcu_ctx, RlcMacDownlink_t);
+	Encoding::write_packet_uplink_ack(bts_data(), mac_control_block, this, final);
+	encode_gsm_rlcmac_downlink(ack_vec, mac_control_block);
+	bitvec_pack(ack_vec, msgb_put(msg, 23));
+	bitvec_free(ack_vec);
+	talloc_free(mac_control_block);
+
+	/* now we must set this flag, so we are allowed to assign downlink
+	 * TBF on PACCH. it is only allowed when TLLI is acknowledged. */
+	m_contention_resolution_done = 1;
+
+	if (final) {
+		poll_state = GPRS_RLCMAC_POLL_SCHED;
+		poll_fn = (fn + 13) % 2715648;
+		/* waiting for final acknowledge */
+		ul_ack_state = GPRS_RLCMAC_UL_ACK_WAIT_ACK;
+		m_final_ack_sent = 1;
+	} else
+		ul_ack_state = GPRS_RLCMAC_UL_ACK_NONE;
+
+	return msg;
+}
+
+int gprs_rlcmac_ul_tbf::rcv_data_block_acknowledged(const uint8_t *data, size_t len, int8_t rssi)
+{
+	struct rlc_ul_header *rh = (struct rlc_ul_header *)data;
+	int rc;
+
+	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", rh->tfi, this->m_window.v_q(),
+		this->m_window.v_r());
+
+	/* process RSSI */
+	gprs_rlcmac_rssi(this, rssi);
+
+	/* get TLLI */
+	if (!this->is_tlli_valid()) {
+		if (!extract_tlli(data, len))
+			return 0;
+	/* already have TLLI, but we stille get another one */
+	} else if (rh->ti) {
+		uint32_t tlli;
+		rc = Decoding::tlli_from_ul_data(data, len, &tlli);
+		if (rc) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "Failed to decode TLLI "
+				"of UL DATA TFI=%d.\n", rh->tfi);
+			return 0;
+		}
+		if (tlli != this->tlli()) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "TLLI mismatch on UL "
+				"DATA TFI=%d. (Ignoring due to contention "
+				"resolution)\n", rh->tfi);
+			return 0;
+		}
+	}
+
+	/* restart T3169 */
+	tbf_timer_start(this, 3169, bts_data()->t3169, 0);
+
+	/* Increment RX-counter */
+	this->m_rx_counter++;
+
+	if (!m_window.is_in_window(rh->bsn)) {
+		LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d out of window "
+			"%d..%d (it's normal)\n", rh->bsn,
+			m_window.v_q(),
+			(m_window.v_q() + ws - 1) & mod_sns);
+		maybe_schedule_uplink_acknack(rh);
+		return 0;
+	}
+
+	/* Write block to buffer and set receive state array. */
+	m_rlc.block(rh->bsn)->put_data(data, len);
+	LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d storing in window (%d..%d)\n",
+		rh->bsn, m_window.v_q(),
+		(m_window.v_q() + ws - 1) & mod_sns);
+
+	/* 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.receive_bsn(rh->bsn);
+
+	/* 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 rlc_ul_header *last_rh = (struct rlc_ul_header *)
+			m_rlc.block((m_window.v_r() - 1) & mod_sns)->block;
+		LOGP(DRLCMACUL, LOGL_DEBUG, "- No gaps in received block, "
+			"last block: BSN=%d CV=%d\n", last_rh->bsn,
+			last_rh->cv);
+		if (last_rh->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(rh);
+
+	return 0;
+}
+
+void gprs_rlcmac_ul_tbf::maybe_schedule_uplink_acknack(const rlc_ul_header *rh)
+{
+	if (rh->si || rh->ti || state_is(GPRS_RLCMAC_FINISHED)
+	 || (m_rx_counter % SEND_ACK_AFTER_FRAMES) == 0) {
+		if (rh->si) {
+			LOGP(DRLCMACUL, LOGL_NOTICE, "- Scheduling Ack/Nack, "
+				"because MS is stalled.\n");
+		}
+		if (rh->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");
+		}
+	}
+}
+
+/* Send Uplink unit-data to SGSN. */
+int gprs_rlcmac_ul_tbf::snd_ul_ud()
+{
+	uint8_t qos_profile[3];
+	struct msgb *llc_pdu;
+	unsigned msg_len = NS_HDR_LEN + BSSGP_HDR_LEN + m_llc.frame_length();
+	struct bssgp_bvc_ctx *bctx = gprs_bssgp_pcu_current_bctx();
+
+	LOGP(DBSSGP, LOGL_INFO, "LLC [PCU -> SGSN] %s len=%d\n", tbf_name(this), m_llc.frame_length());
+	if (!bctx) {
+		LOGP(DBSSGP, LOGL_ERROR, "No bctx\n");
+		m_llc.reset_frame_space();
+		return -EIO;
+	}
+	
+	llc_pdu = msgb_alloc_headroom(msg_len, msg_len,"llc_pdu");
+	uint8_t *buf = msgb_push(llc_pdu, TL16V_GROSS_LEN(sizeof(uint8_t)*m_llc.frame_length()));
+	tl16v_put(buf, BSSGP_IE_LLC_PDU, sizeof(uint8_t)*m_llc.frame_length(), m_llc.frame);
+	qos_profile[0] = QOS_PROFILE >> 16;
+	qos_profile[1] = QOS_PROFILE >> 8;
+	qos_profile[2] = QOS_PROFILE;
+	bssgp_tx_ul_ud(bctx, tlli(), qos_profile, llc_pdu);
+
+	m_llc.reset_frame_space();
+	return 0;
+}
+