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osmo-pcu/src/tbf_dl.cpp

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/* 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 <gprs_rlcmac.h>
#include <gprs_debug.h>
#include <gprs_bssgp_pcu.h>
#include <decoding.h>
#include "pcu_utils.h"
extern "C" {
#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>
}
#include <errno.h>
#include <string.h>
/* After sending these frames, we poll for ack/nack. */
#define POLL_ACK_AFTER_FRAMES 20
static const struct gprs_rlcmac_cs gprs_rlcmac_cs[] = {
/* frame length data block max payload */
{ 0, 0, 0 },
{ 23, 23, 20 }, /* CS-1 */
{ 34, 33, 30 }, /* CS-2 */
{ 40, 39, 36 }, /* CS-3 */
{ 54, 53, 50 }, /* CS-4 */
};
extern "C" {
int bssgp_tx_llc_discarded(struct bssgp_bvc_ctx *bctx, uint32_t tlli,
uint8_t num_frames, uint32_t num_octets);
}
static inline void tbf_update_ms_class(struct gprs_rlcmac_tbf *tbf,
const uint8_t ms_class)
{
if (!tbf->ms_class() && ms_class)
tbf->set_ms_class(ms_class);
}
static void llc_timer_cb(void *_tbf)
{
struct gprs_rlcmac_dl_tbf *tbf = (struct gprs_rlcmac_dl_tbf *)_tbf;
if (tbf->state_is_not(GPRS_RLCMAC_FLOW))
return;
LOGP(DRLCMAC, LOGL_DEBUG,
"%s LLC receive timeout, requesting DL ACK\n", tbf_name(tbf));
tbf->request_dl_ack();
}
void gprs_rlcmac_dl_tbf::cleanup()
{
osmo_timer_del(&m_llc_timer);
}
void gprs_rlcmac_dl_tbf::start_llc_timer()
{
if (bts_data()->llc_idle_ack_csec > 0) {
struct timeval tv;
/* TODO: this ought to be within a constructor */
m_llc_timer.data = this;
m_llc_timer.cb = &llc_timer_cb;
csecs_to_timeval(bts_data()->llc_idle_ack_csec, &tv);
osmo_timer_schedule(&m_llc_timer, tv.tv_sec, tv.tv_usec);
}
}
int gprs_rlcmac_dl_tbf::append_data(const uint8_t ms_class,
const uint16_t pdu_delay_csec,
const uint8_t *data, const uint16_t len)
{
LOGP(DRLCMAC, LOGL_INFO, "%s append\n", tbf_name(this));
if (state_is(GPRS_RLCMAC_WAIT_RELEASE)) {
LOGP(DRLCMAC, LOGL_DEBUG,
"%s in WAIT RELEASE state "
"(T3193), so reuse TBF\n", tbf_name(this));
tbf_update_ms_class(this, ms_class);
reuse_tbf(data, len);
} else if (!have_data()) {
m_llc.put_frame(data, len);
bts->llc_frame_sched();
/* it is no longer drained */
m_last_dl_drained_fn = -1;
tbf_update_ms_class(this, ms_class);
start_llc_timer();
} else {
/* TODO: put this path into an llc_enqueue method */
/* the TBF exists, so we must write it in the queue
* we prepend lifetime in front of PDU */
struct timeval *tv;
struct msgb *llc_msg = msgb_alloc(len + sizeof(*tv) * 2,
"llc_pdu_queue");
if (!llc_msg)
return -ENOMEM;
tv = (struct timeval *)msgb_put(llc_msg, sizeof(*tv));
gprs_llc_queue::calc_pdu_lifetime(bts, pdu_delay_csec, tv);
tv = (struct timeval *)msgb_put(llc_msg, sizeof(*tv));
gettimeofday(tv, NULL);
memcpy(msgb_put(llc_msg, len), data, len);
llc_queue()->enqueue(llc_msg);
tbf_update_ms_class(this, ms_class);
start_llc_timer();
}
return 0;
}
static struct gprs_rlcmac_dl_tbf *tbf_lookup_dl(BTS *bts,
const uint32_t tlli, const uint32_t tlli_old,
const char *imsi)
{
GprsMs *ms = bts->ms_store().get_ms(tlli, tlli_old, imsi);
if (!ms)
return NULL;
return ms->dl_tbf();
}
static int tbf_new_dl_assignment(struct gprs_rlcmac_bts *bts,
const char *imsi,
const uint32_t tlli, const uint32_t tlli_old,
const uint8_t ms_class,
const uint8_t *data, const uint16_t len)
{
uint8_t trx, ss;
int8_t use_trx;
uint16_t ta = 0;
struct gprs_rlcmac_ul_tbf *ul_tbf = NULL, *old_ul_tbf;
struct gprs_rlcmac_dl_tbf *dl_tbf = NULL;
int8_t tfi; /* must be signed */
GprsMs *ms;
/* check for uplink data, so we copy our informations */
#warning "Do the same look up for IMSI, TLLI and OLD_TLLI"
#warning "Refactor the below lines... into a new method"
ms = bts->bts->ms_store().get_ms(tlli, tlli_old, imsi);
if (ms) {
ul_tbf = ms->ul_tbf();
ta = ms->ta();
}
if (ul_tbf && ul_tbf->m_contention_resolution_done
&& !ul_tbf->m_final_ack_sent) {
use_trx = ul_tbf->trx->trx_no;
ss = 0;
old_ul_tbf = ul_tbf;
} else {
use_trx = -1;
ss = 1; /* PCH assignment only allows one timeslot */
old_ul_tbf = NULL;
}
// Create new TBF (any TRX)
#warning "Copy and paste with alloc_ul_tbf"
tfi = bts->bts->tfi_find_free(GPRS_RLCMAC_DL_TBF, &trx, use_trx);
if (tfi >= 0)
/* set number of downlink slots according to multislot class */
dl_tbf = tbf_alloc_dl_tbf(bts, ul_tbf, tfi, trx, ms_class, ss);
if (!dl_tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH resource\n");
bssgp_tx_llc_discarded(gprs_bssgp_pcu_current_bctx(), tlli,
1, len);
bts->bts->llc_dropped_frame();
return -EBUSY;
}
dl_tbf->update_ms(tlli, GPRS_RLCMAC_DL_TBF);
dl_tbf->ms()->set_ta(ta);
LOGP(DRLCMAC, LOGL_DEBUG, "%s [DOWNLINK] START\n", tbf_name(dl_tbf));
/* new TBF, so put first frame */
dl_tbf->m_llc.put_frame(data, len);
dl_tbf->bts->llc_frame_sched();
/* Store IMSI for later look-up and PCH retransmission */
dl_tbf->assign_imsi(imsi);
/* trigger downlink assignment and set state to ASSIGN.
* we don't use old_downlink, so the possible uplink is used
* to trigger downlink assignment. if there is no uplink,
* AGCH is used. */
dl_tbf->bts->trigger_dl_ass(dl_tbf, old_ul_tbf);
return 0;
}
/**
* TODO: split into unit test-able parts...
*/
int gprs_rlcmac_dl_tbf::handle(struct gprs_rlcmac_bts *bts,
const uint32_t tlli, const uint32_t tlli_old, const char *imsi,
const uint8_t ms_class, const uint16_t delay_csec,
const uint8_t *data, const uint16_t len)
{
struct gprs_rlcmac_dl_tbf *dl_tbf;
/* check for existing TBF */
dl_tbf = tbf_lookup_dl(bts->bts, tlli, tlli_old, imsi);
if (dl_tbf) {
int rc = dl_tbf->append_data(ms_class, delay_csec, data, len);
if (rc >= 0)
dl_tbf->assign_imsi(imsi);
if (dl_tbf->ms())
dl_tbf->ms()->confirm_tlli(tlli);
return rc;
}
return tbf_new_dl_assignment(bts, imsi, tlli, tlli_old, ms_class, data, len);
}
struct msgb *gprs_rlcmac_dl_tbf::llc_dequeue(bssgp_bvc_ctx *bctx)
{
struct msgb *msg;
struct timeval *tv_recv, *tv_disc;
struct timeval tv_now, tv_now2;
uint32_t octets = 0, frames = 0;
struct timeval hyst_delta = {0, 0};
const unsigned keep_small_thresh = 60;
if (bts_data()->llc_discard_csec)
csecs_to_timeval(bts_data()->llc_discard_csec, &hyst_delta);
gettimeofday(&tv_now, NULL);
timeradd(&tv_now, &hyst_delta, &tv_now2);
while ((msg = llc_queue()->dequeue())) {
tv_disc = (struct timeval *)msg->data;
msgb_pull(msg, sizeof(*tv_disc));
tv_recv = (struct timeval *)msg->data;
msgb_pull(msg, sizeof(*tv_recv));
gprs_bssgp_update_queue_delay(tv_recv, &tv_now);
/* Is the age below the low water mark? */
if (!gprs_llc_queue::is_frame_expired(&tv_now2, tv_disc))
break;
/* Is the age below the high water mark */
if (!gprs_llc_queue::is_frame_expired(&tv_now, tv_disc)) {
/* Has the previous message not been dropped? */
if (frames == 0)
break;
/* Hysteresis mode, try to discard LLC messages until
* the low water mark has been reached */
/* Check whether to abort the hysteresis mode */
/* Is the frame small, perhaps only a TCP ACK? */
if (msg->len <= keep_small_thresh)
break;
/* Is it a GMM message? */
if (!gprs_llc::is_user_data_frame(msg->data, msg->len))
break;
}
bts->llc_timedout_frame();
frames++;
octets += msg->len;
msgb_free(msg);
bts->llc_dropped_frame();
continue;
}
if (frames) {
LOGP(DRLCMACDL, LOGL_NOTICE, "%s Discarding LLC PDU "
"because lifetime limit reached, "
"count=%u new_queue_size=%zu\n",
tbf_name(this), frames, llc_queue()->size());
if (frames > 0xff)
frames = 0xff;
if (octets > 0xffffff)
octets = 0xffffff;
bssgp_tx_llc_discarded(bctx, tlli(), frames, octets);
}
return msg;
}
/*
* Create DL data block
* The messages are fragmented and forwarded as data blocks.
*/
struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(uint32_t fn, uint8_t ts)
{
LOGP(DRLCMACDL, LOGL_DEBUG, "%s downlink (V(A)==%d .. "
"V(S)==%d)\n", tbf_name(this),
m_window.v_a(), m_window.v_s());
do_resend:
/* check if there is a block with negative acknowledgement */
int resend_bsn = m_window.resend_needed();
if (resend_bsn >= 0) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Resending BSN %d\n", resend_bsn);
/* re-send block with negative aknowlegement */
m_window.m_v_b.mark_unacked(resend_bsn);
bts->rlc_resent();
return create_dl_acked_block(fn, ts, resend_bsn);
}
/* if the window has stalled, or transfer is complete,
* send an unacknowledged block */
if (state_is(GPRS_RLCMAC_FINISHED)) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Restarting at BSN %d, "
"because all blocks have been transmitted.\n",
m_window.v_a());
bts->rlc_restarted();
} else if (dl_window_stalled()) {
LOGP(DRLCMACDL, LOGL_NOTICE, "- Restarting at BSN %d, "
"because all window is stalled.\n",
m_window.v_a());
bts->rlc_stalled();
} else if (have_data()) {
/* New blocks may be send */
return create_new_bsn(fn, ts);
} else if (!m_window.window_empty()) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Restarting at BSN %d, "
"because all blocks have been transmitted (FLOW).\n",
m_window.v_a());
bts->rlc_restarted();
} else {
/* Nothing left to send, create dummy LLC commands */
return create_new_bsn(fn, ts);
}
/* If V(S) == V(A) and finished state, we would have received
* acknowledgement of all transmitted block. In this case we
* would have transmitted the final block, and received ack
* from MS. But in this case we did not receive the final ack
* indication from MS. This should never happen if MS works
* correctly. */
if (m_window.window_empty()) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- MS acked all blocks, "
"so we re-transmit final block!\n");
/* we just send final block again */
int16_t index = m_window.v_s_mod(-1);
bts->rlc_resent();
return create_dl_acked_block(fn, ts, index);
}
/* cycle through all unacked blocks */
int resend = m_window.mark_for_resend();
/* At this point there should be at least one unacked block
* to be resent. If not, this is an software error. */
if (resend == 0) {
LOGP(DRLCMACDL, LOGL_ERROR, "Software error: "
"There are no unacknowledged blocks, but V(A) "
" != V(S). PLEASE FIX!\n");
/* we just send final block again */
int16_t index = m_window.v_s_mod(-1);
return create_dl_acked_block(fn, ts, index);
}
goto do_resend;
}
struct msgb *gprs_rlcmac_dl_tbf::create_new_bsn(const uint32_t fn, const uint8_t ts)
{
struct rlc_dl_header *rh;
struct rlc_li_field *li;
struct msgb *msg;
uint8_t *delimiter, *data, *e_pointer;
uint16_t space, chunk;
gprs_rlc_data *rlc_data;
const uint16_t bsn = m_window.v_s();
uint8_t cs = 1;
LOGP(DRLCMACDL, LOGL_DEBUG, "- Sending new block at BSN %d\n",
m_window.v_s());
cs = current_cs();
OSMO_ASSERT(cs >= 1);
OSMO_ASSERT(cs <= 4);
/* total length of block, including spare bits */
const uint8_t block_length = gprs_rlcmac_cs[cs].block_length;
/* length of usable data of block, w/o spare bits, inc. MAC */
const uint8_t block_data_len = gprs_rlcmac_cs[cs].block_data;
/* now we still have untransmitted LLC data, so we fill mac block */
rlc_data = m_rlc.block(bsn);
data = rlc_data->prepare(block_data_len);
rlc_data->cs = cs;
rh = (struct rlc_dl_header *)data;
rh->pt = 0; /* Data Block */
rh->rrbp = rh->s_p = 0; /* Polling, set later, if required */
rh->usf = 7; /* will be set at scheduler */
rh->pr = 0; /* FIXME: power reduction */
rh->tfi = m_tfi; /* TFI */
rh->fbi = 0; /* Final Block Indicator, set late, if true */
rh->bsn = bsn; /* Block Sequence Number */
rh->e = 0; /* Extension bit, maybe set later */
e_pointer = data + 2; /* points to E of current chunk */
data += sizeof(*rh);
delimiter = data; /* where next length header would be stored */
space = block_data_len - sizeof(*rh);
while (1) {
if (m_llc.frame_length() == 0) {
/* A header will need to by added, so we just need
* space-1 octets */
m_llc.put_dummy_frame(space - 1);
/* The data just drained, store the current fn */
if (m_last_dl_drained_fn < 0)
m_last_dl_drained_fn = fn;
/* It is not clear, when the next real data will
* arrive, so request a DL ack/nack now */
request_dl_ack();
LOGP(DRLCMACDL, LOGL_DEBUG,
"-- Empty chunk, "
"added LLC dummy command of size %d, "
"drained_since=%d\n",
m_llc.frame_length(), frames_since_last_drain(fn));
}
chunk = m_llc.chunk_size();
/* if chunk will exceed block limit */
if (chunk > space) {
LOGP(DRLCMACDL, LOGL_DEBUG, "-- Chunk with length %d "
"larger than space (%d) left in block: copy "
"only remaining space, and we are done\n",
chunk, space);
/* block is filled, so there is no extension */
*e_pointer |= 0x01;
/* fill only space */
m_llc.consume(data, space);
/* return data block as message */
break;
}
/* if FINAL chunk would fit precisely in space left */
if (chunk == space && llc_queue()->size() == 0 && !keep_open(fn))
{
LOGP(DRLCMACDL, LOGL_DEBUG, "-- Chunk with length %d "
"would exactly fit into space (%d): because "
"this is a final block, we don't add length "
"header, and we are done\n", chunk, space);
LOGP(DRLCMACDL, LOGL_INFO, "Complete DL frame for "
"%s that fits precisely in last block: "
"len=%d\n", tbf_name(this), m_llc.frame_length());
gprs_rlcmac_dl_bw(this, m_llc.frame_length());
/* block is filled, so there is no extension */
*e_pointer |= 0x01;
/* fill space */
m_llc.consume(data, space);
m_llc.reset();
/* final block */
rh->fbi = 1; /* we indicate final block */
request_dl_ack();
set_state(GPRS_RLCMAC_FINISHED);
/* return data block as message */
break;
}
/* if chunk would fit exactly in space left */
if (chunk == space) {
LOGP(DRLCMACDL, LOGL_DEBUG, "-- Chunk with length %d "
"would exactly fit into space (%d): add length "
"header with LI=0, to make frame extend to "
"next block, and we are done\n", chunk, space);
/* make space for delimiter */
if (delimiter != data)
memmove(delimiter + 1, delimiter,
data - delimiter);
data++;
space--;
/* add LI with 0 length */
li = (struct rlc_li_field *)delimiter;
li->e = 1; /* not more extension */
li->m = 0; /* shall be set to 0, in case of li = 0 */
li->li = 0; /* chunk fills the complete space */
// no need to set e_pointer nor increase delimiter
/* fill only space, which is 1 octet less than chunk */
m_llc.consume(data, space);
/* return data block as message */
break;
}
LOGP(DRLCMACDL, LOGL_DEBUG, "-- Chunk with length %d is less "
"than remaining space (%d): add length header to "
"to delimit LLC frame\n", chunk, space);
/* the LLC frame chunk ends in this block */
/* make space for delimiter */
if (delimiter != data)
memmove(delimiter + 1, delimiter, data - delimiter);
data++;
space--;
/* add LI to delimit frame */
li = (struct rlc_li_field *)delimiter;
li->e = 0; /* Extension bit, maybe set later */
li->m = 0; /* will be set later, if there is more LLC data */
li->li = chunk; /* length of chunk */
e_pointer = delimiter; /* points to E of current delimiter */
delimiter++;
/* copy (rest of) LLC frame to space and reset later */
m_llc.consume(data, chunk);
data += chunk;
space -= chunk;
LOGP(DRLCMACDL, LOGL_INFO, "Complete DL frame for %s"
"len=%d\n", tbf_name(this), m_llc.frame_length());
gprs_rlcmac_dl_bw(this, m_llc.frame_length());
m_llc.reset();
/* dequeue next LLC frame, if any */
msg = llc_dequeue(gprs_bssgp_pcu_current_bctx());
if (msg) {
LOGP(DRLCMACDL, LOGL_INFO, "- Dequeue next LLC for "
"%s (len=%d)\n", tbf_name(this), msg->len);
m_llc.put_frame(msg->data, msg->len);
bts->llc_frame_sched();
msgb_free(msg);
m_last_dl_drained_fn = -1;
}
/* if we have more data and we have space left */
if (space > 0 && (m_llc.frame_length() || keep_open(fn))) {
li->m = 1; /* we indicate more frames to follow */
continue;
}
/* if we don't have more LLC frames */
if (!m_llc.frame_length() && !keep_open(fn)) {
LOGP(DRLCMACDL, LOGL_DEBUG, "-- Final block, so we "
"done.\n");
li->e = 1; /* we cannot extend */
rh->fbi = 1; /* we indicate final block */
request_dl_ack();
set_state(GPRS_RLCMAC_FINISHED);
break;
}
/* we have no space left */
LOGP(DRLCMACDL, LOGL_DEBUG, "-- No space left, so we are "
"done.\n");
li->e = 1; /* we cannot extend */
break;
}
LOGP(DRLCMACDL, LOGL_DEBUG, "data block: %s\n",
osmo_hexdump(rlc_data->block, block_length));
#warning "move this up?"
rlc_data->len = block_length;
/* raise send state and set ack state array */
m_window.m_v_b.mark_unacked(bsn);
m_window.increment_send();
return create_dl_acked_block(fn, ts, bsn);
}
struct msgb *gprs_rlcmac_dl_tbf::create_dl_acked_block(
const uint32_t fn, const uint8_t ts,
const int index)
{
uint8_t *data;
struct rlc_dl_header *rh;
struct msgb *dl_msg;
uint8_t len;
bool need_poll;
/* get data and header from current block */
data = m_rlc.block(index)->block;
len = m_rlc.block(index)->len;
rh = (struct rlc_dl_header *)data;
/* If the TBF has just started, relate frames_since_last_poll to the
* current fn */
if (m_last_dl_poll_fn < 0)
m_last_dl_poll_fn = fn;
need_poll = state_flags & (1 << GPRS_RLCMAC_FLAG_TO_DL_ACK);
/* Clear Polling, if still set in history buffer */
rh->s_p = 0;
/* poll after POLL_ACK_AFTER_FRAMES frames, or when final block is tx.
*/
if (m_tx_counter >= POLL_ACK_AFTER_FRAMES || m_dl_ack_requested ||
need_poll) {
if (m_dl_ack_requested) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Scheduling Ack/Nack "
"polling, because is was requested explicitly "
"(e.g. first final block sent).\n");
} else if (need_poll) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Scheduling Ack/Nack "
"polling, because polling timed out.\n");
} else {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Scheduling Ack/Nack "
"polling, because %d blocks sent.\n",
POLL_ACK_AFTER_FRAMES);
}
/* scheduling not possible, because: */
if (poll_state != GPRS_RLCMAC_POLL_NONE)
LOGP(DRLCMACDL, LOGL_DEBUG, "Polling is already "
"sheduled for %s, so we must wait for "
"requesting downlink ack\n", tbf_name(this));
else if (control_ts != ts)
LOGP(DRLCMACDL, LOGL_DEBUG, "Polling cannot be "
"sheduled in this TS %d, waiting for "
"TS %d\n", ts, control_ts);
else if (bts->sba()->find(trx->trx_no, ts, (fn + 13) % 2715648))
LOGP(DRLCMACDL, LOGL_DEBUG, "Polling cannot be "
"sheduled, because single block alllocation "
"already exists\n");
else {
LOGP(DRLCMACDL, LOGL_DEBUG, "Polling sheduled in this "
"TS %d\n", ts);
m_tx_counter = 0;
/* start timer whenever we send the final block */
if (rh->fbi == 1)
tbf_timer_start(this, 3191, bts_data()->t3191, 0);
/* schedule polling */
poll_state = GPRS_RLCMAC_POLL_SCHED;
poll_fn = (fn + 13) % 2715648;
/* Clear poll timeout flag */
state_flags &= ~(1 << GPRS_RLCMAC_FLAG_TO_DL_ACK);
/* Clear request flag */
m_dl_ack_requested = false;
/* set polling in header */
rh->rrbp = 0; /* N+13 */
rh->s_p = 1; /* Polling */
m_last_dl_poll_fn = poll_fn;
}
}
/* return data block as message */
dl_msg = msgb_alloc(len, "rlcmac_dl_data");
if (!dl_msg)
return NULL;
/* Increment TX-counter */
m_tx_counter++;
memcpy(msgb_put(dl_msg, len), data, len);
bts->rlc_sent();
return dl_msg;
}
static uint16_t bitnum_to_bsn(int bitnum, uint16_t ssn, uint16_t mod_sns)
{
return (ssn - 1 - bitnum) & mod_sns;
}
int gprs_rlcmac_dl_tbf::analyse_errors(char *show_rbb, uint8_t ssn)
{
gprs_rlc_data *rlc_data;
uint16_t lost = 0, received = 0, skipped = 0;
/* SSN - 1 is in range V(A)..V(S)-1 */
for (int bitpos = 0; bitpos < m_window.ws(); bitpos++) {
uint16_t bsn = bitnum_to_bsn(bitpos, ssn, m_window.mod_sns());
if (bsn == ((m_window.v_a() - 1) & m_window.mod_sns()))
break;
rlc_data = m_rlc.block(bsn);
if (!rlc_data)
continue;
if (rlc_data->cs != current_cs()) {
/* This block has already been encoded with a different
* CS, so it doesn't help us to decide, whether the
* current CS is ok. Ignore it. */
skipped += 1;
continue;
}
if (show_rbb[m_window.ws() - 1 - bitpos] == 'R') {
if (!m_window.m_v_b.is_acked(bsn))
received += 1;
} else {
lost += 1;
}
}
LOGP(DRLCMACDL, LOGL_DEBUG, "%s DL analysis, range=%d:%d, lost=%d, recv=%d, skipped=%d\n",
name(), m_window.v_a(), m_window.v_s(), lost, received, skipped);
if (lost + received == 0)
return -1;
return lost * 100 / (lost + received);
}
int gprs_rlcmac_dl_tbf::update_window(const uint8_t ssn, const uint8_t *rbb)
{
int16_t dist; /* must be signed */
uint16_t lost = 0, received = 0;
char show_rbb[65];
char show_v_b[RLC_MAX_SNS + 1];
const uint16_t mod_sns = m_window.mod_sns();
int error_rate;
Decoding::extract_rbb(rbb, show_rbb);
/* show received array in debug (bit 64..1) */
LOGP(DRLCMACDL, LOGL_DEBUG, "- ack: (BSN=%d)\"%s\""
"(BSN=%d) R=ACK I=NACK\n", (ssn - 64) & mod_sns,
show_rbb, (ssn - 1) & mod_sns);
/* apply received array to receive state (SSN-64..SSN-1) */
/* calculate distance of ssn from V(S) */
dist = (m_window.v_s() - ssn) & mod_sns;
/* check if distance is less than distance V(A)..V(S) */
if (dist >= m_window.distance()) {
/* this might happpen, if the downlink assignment
* was not received by ms and the ack refers
* to previous TBF
* FIXME: we should implement polling for
* control ack!*/
LOGP(DRLCMACDL, LOGL_NOTICE, "- ack range is out of "
"V(A)..V(S) range %s Free TBF!\n", tbf_name(this));
return 1; /* indicate to free TBF */
}
if (bts_data()->cs_adj_enabled && ms()) {
error_rate = analyse_errors(show_rbb, ssn);
ms()->update_error_rate(this, error_rate);
}
m_window.update(bts, show_rbb, ssn,
&lost, &received);
/* report lost and received packets */
gprs_rlcmac_received_lost(this, received, lost);
/* raise V(A), if possible */
m_window.raise(m_window.move_window());
/* show receive state array in debug (V(A)..V(S)-1) */
m_window.show_state(show_v_b);
LOGP(DRLCMACDL, LOGL_DEBUG, "- V(B): (V(A)=%d)\"%s\""
"(V(S)-1=%d) A=Acked N=Nacked U=Unacked "
"X=Resend-Unacked I=Invalid\n",
m_window.v_a(), show_v_b,
m_window.v_s_mod(-1));
if (state_is(GPRS_RLCMAC_FINISHED) && m_window.window_empty()) {
LOGP(DRLCMACDL, LOGL_NOTICE, "Received acknowledge of "
"all blocks, but without final ack "
"inidcation (don't worry)\n");
}
return 0;
}
int gprs_rlcmac_dl_tbf::maybe_start_new_window()
{
struct msgb *msg;
uint16_t received;
LOGP(DRLCMACDL, LOGL_DEBUG, "- Final ACK received.\n");
/* range V(A)..V(S)-1 */
received = m_window.count_unacked();
/* report all outstanding packets as received */
gprs_rlcmac_received_lost(this, received, 0);
set_state(GPRS_RLCMAC_WAIT_RELEASE);
/* check for LLC PDU in the LLC Queue */
msg = llc_dequeue(gprs_bssgp_pcu_current_bctx());
if (!msg) {
/* no message, start T3193, change state to RELEASE */
LOGP(DRLCMACDL, LOGL_DEBUG, "- No new message, so we release.\n");
/* start T3193 */
tbf_timer_start(this, 3193,
bts_data()->t3193_msec / 1000,
(bts_data()->t3193_msec % 1000) * 1000);
return 0;
}
/* we have more data so we will re-use this tbf */
reuse_tbf(msg->data, msg->len);
msgb_free(msg);
return 0;
}
int gprs_rlcmac_dl_tbf::rcvd_dl_ack(uint8_t final_ack, uint8_t ssn, uint8_t *rbb)
{
LOGP(DRLCMACDL, LOGL_DEBUG, "%s downlink acknowledge\n", tbf_name(this));
if (!final_ack)
return update_window(ssn, rbb);
return maybe_start_new_window();
}
void gprs_rlcmac_dl_tbf::reuse_tbf(const uint8_t *data, const uint16_t len)
{
uint8_t trx;
struct gprs_rlcmac_dl_tbf *new_tbf = NULL;
int8_t tfi; /* must be signed */
bts->tbf_reused();
tfi = bts->tfi_find_free(GPRS_RLCMAC_DL_TBF, &trx, this->trx->trx_no);
if (tfi >= 0)
new_tbf = tbf_alloc_dl_tbf(bts->bts_data(), NULL, tfi, trx,
ms_class(), 0);
if (!new_tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH resource\n");
bssgp_tx_llc_discarded(gprs_bssgp_pcu_current_bctx(), tlli(),
1, len);
bts->llc_dropped_frame();
return;
}
new_tbf->set_ms(ms());
/* Start with the passed frame */
new_tbf->m_llc.put_frame(data, len);
bts->llc_frame_sched();
/* reset rlc states */
m_tx_counter = 0;
m_wait_confirm = 0;
m_window.reset();
/* keep to flags */
state_flags &= GPRS_RLCMAC_FLAG_TO_MASK;
state_flags &= ~(1 << GPRS_RLCMAC_FLAG_CCCH);
update();
LOGP(DRLCMAC, LOGL_DEBUG, "%s Trigger dowlink assignment on PACCH, "
"because another LLC PDU has arrived in between\n",
tbf_name(this));
bts->trigger_dl_ass(new_tbf, this);
}
bool gprs_rlcmac_dl_tbf::dl_window_stalled() const
{
return m_window.window_stalled();
}
void gprs_rlcmac_dl_tbf::request_dl_ack()
{
m_dl_ack_requested = true;
}
bool gprs_rlcmac_dl_tbf::need_control_ts() const
{
if (poll_state != GPRS_RLCMAC_POLL_NONE)
return false;
return state_flags & (1 << GPRS_RLCMAC_FLAG_TO_DL_ACK) ||
m_tx_counter >= POLL_ACK_AFTER_FRAMES ||
m_dl_ack_requested;
}
bool gprs_rlcmac_dl_tbf::have_data() const
{
return m_llc.chunk_size() > 0 ||
(llc_queue() && llc_queue()->size() > 0);
}
int gprs_rlcmac_dl_tbf::frames_since_last_poll(unsigned fn) const
{
unsigned wrapped;
if (m_last_dl_poll_fn < 0)
return -1;
wrapped = (fn + 2715648 - m_last_dl_poll_fn) % 2715648;
if (wrapped < 2715648/2)
return wrapped;
else
return wrapped - 2715648;
}
int gprs_rlcmac_dl_tbf::frames_since_last_drain(unsigned fn) const
{
unsigned wrapped;
if (m_last_dl_drained_fn < 0)
return -1;
wrapped = (fn + 2715648 - m_last_dl_drained_fn) % 2715648;
if (wrapped < 2715648/2)
return wrapped;
else
return wrapped - 2715648;
}
bool gprs_rlcmac_dl_tbf::keep_open(unsigned fn) const
{
int keep_time_frames;
if (bts_data()->dl_tbf_idle_msec <= 0)
return false;
keep_time_frames = msecs_to_frames(bts_data()->dl_tbf_idle_msec);
return frames_since_last_drain(fn) <= keep_time_frames;
}
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