cellular-infrastructure
/
osmo-pcu
mirror of https://gerrit.osmocom.org/osmo-pcu
9
0
Fork 1
Code Issues Releases Wiki Activity

pdch/tbf: Move gprs_rlcmac_rcv_data_block_acknowledged into the pdch 

Move the method into the PDCH. Extract the finding of TLLI into a
new class called Decoding. Move the assemble and forward LLC frames
into the TBF as it is poking in the internals of the TBF.
This commit is contained in:
Holger Hans Peter Freyther 2013-10-26 17:32:04 +02:00
parent 6f9f434463
commit d11290b90b
10 changed files with 571 additions and 472 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
src/Makefile.am
View File

@ -47,7 +47,8 @@ libgprs_la_SOURCES = \
poll_controller.cpp \
encoding.cpp \
ta.cpp \
sba.cpp
sba.cpp \
decoding.cpp
if ENABLE_SYSMOBTS
libgprs_la_SOURCES += \
@ -85,7 +86,9 @@ noinst_HEADERS = \
poll_controller.h \
encoding.h \
ta.h \
sba.h
sba.h \
rlc.h \
decoding.h
osmo_pcu_SOURCES = pcu_main.cpp

235
src/bts.cpp
View File

@ -22,6 +22,8 @@
#include <poll_controller.h>
#include <tbf.h>
#include <encoding.h>
#include <decoding.h>
#include <rlc.h>
#include <gprs_rlcmac.h>
#include <gprs_debug.h>
@ -212,6 +214,14 @@ gprs_rlcmac_tbf *BTS::tbf_by_poll_fn(uint32_t fn, uint8_t trx, uint8_t ts)
return NULL;
}
/*
* PDCH code below. TODO: move to a separate file
*/
/* After receiving these frames, we send ack/nack. */
#define SEND_ACK_AFTER_FRAMES 20
void gprs_rlcmac_pdch::enable()
{
/* TODO: Check if there are still allocated resources.. */
@ -340,6 +350,228 @@ void gprs_rlcmac_pdch::add_paging(struct gprs_rlcmac_paging *pag)
llist_add(&pag->list, &paging_list);
}
/* receive UL data block
*
* The blocks are defragmented and forwarded as LLC frames, if complete.
*/
int gprs_rlcmac_pdch::rcv_data_block_acknowledged(struct gprs_rlcmac_bts *bts,
uint8_t trx, uint8_t ts,
uint8_t *data, uint8_t len, int8_t rssi)
{
struct gprs_rlcmac_tbf *tbf;
struct rlc_ul_header *rh = (struct rlc_ul_header *)data;
uint16_t mod_sns, mod_sns_half, offset_v_q, offset_v_r, index;
int rc;
switch (len) {
case 54:
/* omitting spare bits */
len = 53;
break;
case 40:
/* omitting spare bits */
len = 39;
break;
case 34:
/* omitting spare bits */
len = 33;
break;
case 23:
break;
default:
LOGP(DRLCMACUL, LOGL_ERROR, "Dropping data block with invalid"
"length: %d)\n", len);
return -EINVAL;
}
/* find TBF inst from given TFI */
tbf = tbf_by_tfi(bts, rh->tfi, trx, GPRS_RLCMAC_UL_TBF);
if (!tbf) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA unknown TBF=%d\n",
rh->tfi);
return 0;
}
tbf->state_flags |= (1 << GPRS_RLCMAC_FLAG_UL_DATA);
LOGP(DRLCMACUL, LOGL_DEBUG, "UL DATA TBF=%d received (V(Q)=%d .. "
"V(R)=%d)\n", rh->tfi, tbf->dir.ul.v_q, tbf->dir.ul.v_r);
/* process RSSI */
gprs_rlcmac_rssi(tbf, rssi);
/* get TLLI */
if (!tbf->tlli_valid) {
struct gprs_rlcmac_tbf *dl_tbf, *ul_tbf;
/* no TLLI yet */
if (!rh->ti) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA TBF=%d without "
"TLLI, but no TLLI received yet\n", rh->tfi);
return 0;
}
rc = Decoding::tlli_from_ul_data(data, len, &tbf->tlli);
if (rc) {
LOGP(DRLCMACUL, LOGL_NOTICE, "Failed to decode TLLI "
"of UL DATA TBF=%d.\n", rh->tfi);
return 0;
}
LOGP(DRLCMACUL, LOGL_INFO, "Decoded premier TLLI=0x%08x of "
"UL DATA TBF=%d.\n", tbf->tlli, rh->tfi);
if ((dl_tbf = bts->bts->tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_DL_TBF))) {
LOGP(DRLCMACUL, LOGL_NOTICE, "Got RACH from "
"TLLI=0x%08x while DL TBF=%d still exists. "
"Killing pending DL TBF\n", tbf->tlli,
dl_tbf->tfi);
tbf_free(dl_tbf);
}
/* tbf_by_tlli will not find your TLLI, because it is not
* yet marked valid */
if ((ul_tbf = bts->bts->tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_UL_TBF))) {
LOGP(DRLCMACUL, LOGL_NOTICE, "Got RACH from "
"TLLI=0x%08x while UL TBF=%d still exists. "
"Killing pending UL TBF\n", tbf->tlli,
ul_tbf->tfi);
tbf_free(ul_tbf);
}
/* mark TLLI valid now */
tbf->tlli_valid = 1;
/* store current timing advance */
bts->bts->timing_advance()->remember(tbf->tlli, tbf->ta);
/* 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 TBF=%d.\n", rh->tfi);
return 0;
}
if (tlli != tbf->tlli) {
LOGP(DRLCMACUL, LOGL_NOTICE, "TLLI mismatch on UL "
"DATA TBF=%d. (Ignoring due to contention "
"resolution)\n", rh->tfi);
return 0;
}
}
mod_sns = tbf->sns - 1;
mod_sns_half = (tbf->sns >> 1) - 1;
/* restart T3169 */
tbf_timer_start(tbf, 3169, bts->t3169, 0);
/* Increment RX-counter */
tbf->dir.ul.rx_counter++;
/* current block relative to lowest unreceived block */
offset_v_q = (rh->bsn - tbf->dir.ul.v_q) & mod_sns;
/* If out of window (may happen if blocks below V(Q) are received
* again. */
if (offset_v_q >= tbf->ws) {
LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d out of window "
"%d..%d (it's normal)\n", rh->bsn, tbf->dir.ul.v_q,
(tbf->dir.ul.v_q + tbf->ws - 1) & mod_sns);
return 0;
}
/* Write block to buffer and set receive state array. */
index = rh->bsn & mod_sns_half; /* memory index of block */
memcpy(tbf->rlc_block[index], data, len); /* Copy block. */
tbf->rlc_block_len[index] = len;
tbf->dir.ul.v_n[index] = 'R'; /* Mark received block. */
LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d storing in window (%d..%d)\n",
rh->bsn, tbf->dir.ul.v_q,
(tbf->dir.ul.v_q + tbf->ws - 1) & mod_sns);
/* Raise V(R) to highest received sequence number not received. */
offset_v_r = (rh->bsn + 1 - tbf->dir.ul.v_r) & mod_sns;
if (offset_v_r < (tbf->sns >> 1)) { /* Positive offset, so raise. */
while (offset_v_r--) {
if (offset_v_r) /* all except the received block */
tbf->dir.ul.v_n[tbf->dir.ul.v_r & mod_sns_half]
= 'N'; /* Mark block as not received */
tbf->dir.ul.v_r = (tbf->dir.ul.v_r + 1) & mod_sns;
/* Inc V(R). */
}
LOGP(DRLCMACUL, LOGL_DEBUG, "- Raising V(R) to %d\n",
tbf->dir.ul.v_r);
}
/* 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.*/
while (tbf->dir.ul.v_q != tbf->dir.ul.v_r && tbf->dir.ul.v_n[
(index = tbf->dir.ul.v_q & mod_sns_half)] == 'R') {
LOGP(DRLCMACUL, LOGL_DEBUG, "- Taking block %d out, raising "
"V(Q) to %d\n", tbf->dir.ul.v_q,
(tbf->dir.ul.v_q + 1) & mod_sns);
/* get LLC data from block */
tbf->assemble_forward_llc(tbf->rlc_block[index], tbf->rlc_block_len[index]);
/* raise V(Q), because block already received */
tbf->dir.ul.v_q = (tbf->dir.ul.v_q + 1) & mod_sns;
}
/* Check CV of last frame in buffer */
if (tbf->state_is(GPRS_RLCMAC_FLOW) /* still in flow state */
&& tbf->dir.ul.v_q == tbf->dir.ul.v_r) { /* if complete */
struct rlc_ul_header *last_rh = (struct rlc_ul_header *)
tbf->rlc_block[(tbf->dir.ul.v_r - 1) & mod_sns_half];
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");
tbf_new_state(tbf, GPRS_RLCMAC_FINISHED);
/* Reset N3103 counter. */
tbf->dir.ul.n3103 = 0;
}
}
/* If TLLI is included or if we received half of the window, we send
* an ack/nack */
if (rh->si || rh->ti || tbf->state_is(GPRS_RLCMAC_FINISHED)
|| (tbf->dir.ul.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 (tbf->state_is(GPRS_RLCMAC_FINISHED)) {
LOGP(DRLCMACUL, LOGL_DEBUG, "- Scheduling Ack/Nack, "
"because last block has CV==0.\n");
}
if ((tbf->dir.ul.rx_counter % SEND_ACK_AFTER_FRAMES) == 0) {
LOGP(DRLCMACUL, LOGL_DEBUG, "- Scheduling Ack/Nack, "
"because %d frames received.\n",
SEND_ACK_AFTER_FRAMES);
}
if (tbf->ul_ack_state == GPRS_RLCMAC_UL_ACK_NONE) {
#ifdef DEBUG_DIAGRAM
if (rh->si)
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK stall");
if (rh->ti)
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK TLLI");
if (tbf->state_is(GPRS_RLCMAC_FINISHED))
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK CV==0");
if ((tbf->dir.ul.rx_counter % SEND_ACK_AFTER_FRAMES) == 0)
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK n=%d",
tbf->dir.ul.rx_counter);
#endif
/* trigger sending at next RTS */
tbf->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");
}
}
return 0;
}
/* received RLC/MAC block from L1 */
int gprs_rlcmac_pdch::rcv_block(uint8_t *data, uint8_t len, uint32_t fn, int8_t rssi)
{
@ -351,8 +583,7 @@ int gprs_rlcmac_pdch::rcv_block(uint8_t *data, uint8_t len, uint32_t fn, int8_t
switch (payload) {
case GPRS_RLCMAC_DATA_BLOCK:
rc = gprs_rlcmac_rcv_data_block_acknowledged(bts, trx_no, ts_no, data,
len, rssi);
rc = rcv_data_block_acknowledged(bts, trx_no, ts_no, data, len, rssi);
break;
case GPRS_RLCMAC_CONTROL_BLOCK:
block = bitvec_alloc(len);

8
src/bts.h
View File

@ -70,6 +70,14 @@ struct gprs_rlcmac_pdch {
/* back pointers */
struct gprs_rlcmac_trx *trx;
uint8_t ts_no;
#ifdef __cplusplus
private:
int rcv_data_block_acknowledged(struct gprs_rlcmac_bts *bts,
uint8_t trx, uint8_t ts,
uint8_t *data, uint8_t len, int8_t rssi);
#endif
};
struct gprs_rlcmac_trx {

70
src/decoding.cpp Normal file
View File

@ -0,0 +1,70 @@
/* decoding
*
* Copyright (C) 2012 Ivan Klyuchnikov
* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
*
* 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 <decoding.h>
#include <rlc.h>
#include <gprs_debug.h>
#include <arpa/inet.h>
#include <errno.h>
#include <string.h>
int Decoding::tlli_from_ul_data(const uint8_t *data, uint8_t len,
uint32_t *tlli)
{
struct rlc_ul_header *rh = (struct rlc_ul_header *)data;
struct rlc_li_field *li;
uint8_t e;
uint32_t _tlli;
if (!rh->ti)
return -EINVAL;
data += 3;
len -= 3;
e = rh->e;
/* if E is not set (LI follows) */
while (!e) {
if (!len) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI extended, "
"but no more data\n");
return -EINVAL;
}
/* get new E */
li = (struct rlc_li_field *)data;
if (li->e == 0) /* if LI==0, E is interpreted as '1' */
e = 1;
else
e = li->e;
data++;
len--;
}
if (len < 4) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA TLLI out of frame "
"border\n");
return -EINVAL;
}
memcpy(&_tlli, data, 4);
*tlli = ntohl(_tlli);
return 0;
}

28
src/decoding.h Normal file
View File

@ -0,0 +1,28 @@
/* decoding
*
* Copyright (C) 2012 Ivan Klyuchnikov
* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
*
* 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.
*/
#pragma once
#include <stdint.h>
class Decoding {
public:
static int tlli_from_ul_data(const uint8_t *data, uint8_t len,
uint32_t *tlli);
};

4
src/gprs_rlcmac.h
View File

@ -119,10 +119,6 @@ int gprs_rlcmac_downlink_ack(
int gprs_rlcmac_paging_request(uint8_t *ptmsi, uint16_t ptmsi_len,
const char *imsi);
int gprs_rlcmac_rcv_data_block_acknowledged(struct gprs_rlcmac_bts *bts,
uint8_t trx, uint8_t ts,
uint8_t *data, uint8_t len, int8_t rssi);
struct msgb *gprs_rlcmac_send_data_block_acknowledged(
struct gprs_rlcmac_tbf *tbf, uint32_t fn, uint8_t ts);

465
src/gprs_rlcmac_data.cpp
View File

@ -24,6 +24,7 @@
#include <bts.h>
#include <encoding.h>
#include <tbf.h>
#include <rlc.h>
static struct gprs_rlcmac_cs gprs_rlcmac_cs[] = {
/* frame length data block max payload */
@ -37,9 +38,6 @@ static struct gprs_rlcmac_cs gprs_rlcmac_cs[] = {
extern void *tall_pcu_ctx;
/* After receiving these frames, we send ack/nack. */
#define SEND_ACK_AFTER_FRAMES 20
/* After sending these frames, we poll for ack/nack. */
#define POLL_ACK_AFTER_FRAMES 20
@ -47,39 +45,6 @@ extern void *tall_pcu_ctx;
#define POLLING_ASSIGNMENT_DL 1
#define POLLING_ASSIGNMENT_UL 1
extern "C" {
/* TS 04.60 10.2.2 */
struct rlc_ul_header {
uint8_t r:1,
si:1,
cv:4,
pt:2;
uint8_t ti:1,
tfi:5,
pi:1,
spare:1;
uint8_t e:1,
bsn:7;
} __attribute__ ((packed));
struct rlc_dl_header {
uint8_t usf:3,
s_p:1,
rrbp:2,
pt:2;
uint8_t fbi:1,
tfi:5,
pr:2;
uint8_t e:1,
bsn:7;
} __attribute__ ((packed));
struct rlc_li_field {
uint8_t e:1,
m:1,
li:6;
} __attribute__ ((packed));
}
static void gprs_rlcmac_downlink_assignment(
gprs_rlcmac_tbf *tbf, uint8_t poll,
@ -469,212 +434,6 @@ int gprs_rlcmac_rcv_control_block(struct gprs_rlcmac_bts *bts,
* UL data block flow
*/
/* get TLLI from received UL data block */
static int tlli_from_ul_data(uint8_t *data, uint8_t len, uint32_t *tlli)
{
struct rlc_ul_header *rh = (struct rlc_ul_header *)data;
struct rlc_li_field *li;
uint8_t e;
uint32_t _tlli;
if (!rh->ti)
return -EINVAL;
data += 3;
len -= 3;
e = rh->e;
/* if E is not set (LI follows) */
while (!e) {
if (!len) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA LI extended, "
"but no more data\n");
return -EINVAL;
}
/* get new E */
li = (struct rlc_li_field *)data;
if (li->e == 0) /* if LI==0, E is interpreted as '1' */
e = 1;
else
e = li->e;
data++;
len--;
}
if (len < 4) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA TLLI out of frame "
"border\n");
return -EINVAL;
}
memcpy(&_tlli, data, 4);
*tlli = ntohl(_tlli);
return 0;
}
/* Store received block data in LLC message(s) and forward to SGSN if complete.
*/
static int gprs_rlcmac_assemble_llc(struct gprs_rlcmac_tbf *tbf, uint8_t *data,
uint8_t len)
{
struct rlc_ul_header *rh = (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, "Too many frames in "
"block\n");
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, "UL DATA TBF=%d "
"ignored, because M='0' and E='0'.\n",
tbf->tfi);
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, "UL DATA TLLI out of "
"frame border\n");
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, "UL DATA PFI out of "
"frame border\n");
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, "UL DATA TBF=%d ignored, "
"because LI delimits data that exceeds block size.\n",
tbf->tfi);
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];
}
LOGP(DRLCMACUL, LOGL_DEBUG, "-- Appending chunk (len=%d) to "
"frame at %d.\n", chunk, tbf->llc_index);
if (tbf->llc_index + chunk > LLC_MAX_LEN) {
LOGP(DRLCMACUL, LOGL_NOTICE, "LLC frame exceeds "
"maximum size.\n");
chunk = LLC_MAX_LEN - tbf->llc_index;
}
memcpy(tbf->llc_frame + tbf->llc_index, data + frame_offset[i],
chunk);
tbf->llc_index += chunk;
/* not last frame. */
if (i != frames - 1) {
/* send frame to SGSN */
LOGP(DRLCMACUL, LOGL_INFO, "Complete UL frame for "
"TBF=%d: len=%d\n", tbf->tfi, tbf->llc_index);
gprs_rlcmac_tx_ul_ud(tbf);
tbf->llc_index = 0; /* reset frame space */
/* 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, "Complete UL frame for "
"TBF=%d that fits precisely in last block: "
"len=%d\n", tbf->tfi, tbf->llc_index);
gprs_rlcmac_tx_ul_ud(tbf);
tbf->llc_index = 0; /* reset frame space */
}
}
return 0;
}
struct msgb *gprs_rlcmac_send_uplink_ack(
struct gprs_rlcmac_tbf *tbf,
uint32_t fn)
@ -731,228 +490,6 @@ struct msgb *gprs_rlcmac_send_uplink_ack(
return msg;
}
/* receive UL data block
*
* The blocks are defragmented and forwarded as LLC frames, if complete.
*/
int gprs_rlcmac_rcv_data_block_acknowledged(struct gprs_rlcmac_bts *bts,
uint8_t trx, uint8_t ts,
uint8_t *data, uint8_t len, int8_t rssi)
{
struct gprs_rlcmac_tbf *tbf;
struct rlc_ul_header *rh = (struct rlc_ul_header *)data;
uint16_t mod_sns, mod_sns_half, offset_v_q, offset_v_r, index;
int rc;
switch (len) {
case 54:
/* omitting spare bits */
len = 53;
break;
case 40:
/* omitting spare bits */
len = 39;
break;
case 34:
/* omitting spare bits */
len = 33;
break;
case 23:
break;
default:
LOGP(DRLCMACUL, LOGL_ERROR, "Dropping data block with invalid"
"length: %d)\n", len);
return -EINVAL;
}
/* find TBF inst from given TFI */
tbf = tbf_by_tfi(bts, rh->tfi, trx, GPRS_RLCMAC_UL_TBF);
if (!tbf) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA unknown TBF=%d\n",
rh->tfi);
return 0;
}
tbf->state_flags |= (1 << GPRS_RLCMAC_FLAG_UL_DATA);
LOGP(DRLCMACUL, LOGL_DEBUG, "UL DATA TBF=%d received (V(Q)=%d .. "
"V(R)=%d)\n", rh->tfi, tbf->dir.ul.v_q, tbf->dir.ul.v_r);
/* process RSSI */
gprs_rlcmac_rssi(tbf, rssi);
/* get TLLI */
if (!tbf->tlli_valid) {
struct gprs_rlcmac_tbf *dl_tbf, *ul_tbf;
/* no TLLI yet */
if (!rh->ti) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA TBF=%d without "
"TLLI, but no TLLI received yet\n", rh->tfi);
return 0;
}
rc = tlli_from_ul_data(data, len, &tbf->tlli);
if (rc) {
LOGP(DRLCMACUL, LOGL_NOTICE, "Failed to decode TLLI "
"of UL DATA TBF=%d.\n", rh->tfi);
return 0;
}
LOGP(DRLCMACUL, LOGL_INFO, "Decoded premier TLLI=0x%08x of "
"UL DATA TBF=%d.\n", tbf->tlli, rh->tfi);
if ((dl_tbf = bts->bts->tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_DL_TBF))) {
LOGP(DRLCMACUL, LOGL_NOTICE, "Got RACH from "
"TLLI=0x%08x while DL TBF=%d still exists. "
"Killing pending DL TBF\n", tbf->tlli,
dl_tbf->tfi);
tbf_free(dl_tbf);
}
/* tbf_by_tlli will not find your TLLI, because it is not
* yet marked valid */
if ((ul_tbf = bts->bts->tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_UL_TBF))) {
LOGP(DRLCMACUL, LOGL_NOTICE, "Got RACH from "
"TLLI=0x%08x while UL TBF=%d still exists. "
"Killing pending UL TBF\n", tbf->tlli,
ul_tbf->tfi);
tbf_free(ul_tbf);
}
/* mark TLLI valid now */
tbf->tlli_valid = 1;
/* store current timing advance */
bts->bts->timing_advance()->remember(tbf->tlli, tbf->ta);
/* already have TLLI, but we stille get another one */
} else if (rh->ti) {
uint32_t tlli;
rc = tlli_from_ul_data(data, len, &tlli);
if (rc) {
LOGP(DRLCMACUL, LOGL_NOTICE, "Failed to decode TLLI "
"of UL DATA TBF=%d.\n", rh->tfi);
return 0;
}
if (tlli != tbf->tlli) {
LOGP(DRLCMACUL, LOGL_NOTICE, "TLLI mismatch on UL "
"DATA TBF=%d. (Ignoring due to contention "
"resolution)\n", rh->tfi);
return 0;
}
}
mod_sns = tbf->sns - 1;
mod_sns_half = (tbf->sns >> 1) - 1;
/* restart T3169 */
tbf_timer_start(tbf, 3169, bts->t3169, 0);
/* Increment RX-counter */
tbf->dir.ul.rx_counter++;
/* current block relative to lowest unreceived block */
offset_v_q = (rh->bsn - tbf->dir.ul.v_q) & mod_sns;
/* If out of window (may happen if blocks below V(Q) are received
* again. */
if (offset_v_q >= tbf->ws) {
LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d out of window "
"%d..%d (it's normal)\n", rh->bsn, tbf->dir.ul.v_q,
(tbf->dir.ul.v_q + tbf->ws - 1) & mod_sns);
return 0;
}
/* Write block to buffer and set receive state array. */
index = rh->bsn & mod_sns_half; /* memory index of block */
memcpy(tbf->rlc_block[index], data, len); /* Copy block. */
tbf->rlc_block_len[index] = len;
tbf->dir.ul.v_n[index] = 'R'; /* Mark received block. */
LOGP(DRLCMACUL, LOGL_DEBUG, "- BSN %d storing in window (%d..%d)\n",
rh->bsn, tbf->dir.ul.v_q,
(tbf->dir.ul.v_q + tbf->ws - 1) & mod_sns);
/* Raise V(R) to highest received sequence number not received. */
offset_v_r = (rh->bsn + 1 - tbf->dir.ul.v_r) & mod_sns;
if (offset_v_r < (tbf->sns >> 1)) { /* Positive offset, so raise. */
while (offset_v_r--) {
if (offset_v_r) /* all except the received block */
tbf->dir.ul.v_n[tbf->dir.ul.v_r & mod_sns_half]
= 'N'; /* Mark block as not received */
tbf->dir.ul.v_r = (tbf->dir.ul.v_r + 1) & mod_sns;
/* Inc V(R). */
}
LOGP(DRLCMACUL, LOGL_DEBUG, "- Raising V(R) to %d\n",
tbf->dir.ul.v_r);
}
/* 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.*/
while (tbf->dir.ul.v_q != tbf->dir.ul.v_r && tbf->dir.ul.v_n[
(index = tbf->dir.ul.v_q & mod_sns_half)] == 'R') {
LOGP(DRLCMACUL, LOGL_DEBUG, "- Taking block %d out, raising "
"V(Q) to %d\n", tbf->dir.ul.v_q,
(tbf->dir.ul.v_q + 1) & mod_sns);
/* get LLC data from block */
gprs_rlcmac_assemble_llc(tbf, tbf->rlc_block[index],
tbf->rlc_block_len[index]);
/* raise V(Q), because block already received */
tbf->dir.ul.v_q = (tbf->dir.ul.v_q + 1) & mod_sns;
}
/* Check CV of last frame in buffer */
if (tbf->state_is(GPRS_RLCMAC_FLOW) /* still in flow state */
&& tbf->dir.ul.v_q == tbf->dir.ul.v_r) { /* if complete */
struct rlc_ul_header *last_rh = (struct rlc_ul_header *)
tbf->rlc_block[(tbf->dir.ul.v_r - 1) & mod_sns_half];
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");
tbf_new_state(tbf, GPRS_RLCMAC_FINISHED);
/* Reset N3103 counter. */
tbf->dir.ul.n3103 = 0;
}
}
/* If TLLI is included or if we received half of the window, we send
* an ack/nack */
if (rh->si || rh->ti || tbf->state_is(GPRS_RLCMAC_FINISHED)
|| (tbf->dir.ul.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 (tbf->state_is(GPRS_RLCMAC_FINISHED)) {
LOGP(DRLCMACUL, LOGL_DEBUG, "- Scheduling Ack/Nack, "
"because last block has CV==0.\n");
}
if ((tbf->dir.ul.rx_counter % SEND_ACK_AFTER_FRAMES) == 0) {
LOGP(DRLCMACUL, LOGL_DEBUG, "- Scheduling Ack/Nack, "
"because %d frames received.\n",
SEND_ACK_AFTER_FRAMES);
}
if (tbf->ul_ack_state == GPRS_RLCMAC_UL_ACK_NONE) {
#ifdef DEBUG_DIAGRAM
if (rh->si)
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK stall");
if (rh->ti)
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK TLLI");
if (tbf->state_is(GPRS_RLCMAC_FINISHED))
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK CV==0");
if ((tbf->dir.ul.rx_counter % SEND_ACK_AFTER_FRAMES) == 0)
debug_diagram(bts->bts, tbf->diag, "sched UL-ACK n=%d",
tbf->dir.ul.rx_counter);
#endif
/* trigger sending at next RTS */
tbf->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");
}
}
return 0;
}
struct msgb *gprs_rlcmac_send_packet_uplink_assignment(
struct gprs_rlcmac_tbf *tbf, uint32_t fn)
{

56
src/rlc.h Normal file
View File

@ -0,0 +1,56 @@
/* rlc header descriptions
*
* Copyright (C) 2012 Ivan Klyuchnikov
* Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
*
* 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.
*/
#pragma once
#include <stdint.h>
extern "C" {
/* TS 04.60 10.2.2 */
struct rlc_ul_header {
uint8_t r:1,
si:1,
cv:4,
pt:2;
uint8_t ti:1,
tfi:5,
pi:1,
spare:1;
uint8_t e:1,
bsn:7;
} __attribute__ ((packed));
struct rlc_dl_header {
uint8_t usf:3,
s_p:1,
rrbp:2,
pt:2;
uint8_t fbi:1,
tfi:5,
pr:2;
uint8_t e:1,
bsn:7;
} __attribute__ ((packed));
struct rlc_li_field {
uint8_t e:1,
m:1,
li:6;
} __attribute__ ((packed));
}

167
src/tbf.cpp
View File

@ -21,6 +21,7 @@
#include <bts.h>
#include <tbf.h>
#include <rlc.h>
#include <gprs_rlcmac.h>
#include <gprs_debug.h>
@ -626,6 +627,172 @@ void gprs_rlcmac_tbf::update_llc_frame(struct msgb *msg)
llc_length = msg->len;
}
/*
* Store received block data in LLC message(s) and forward to SGSN
* if complete.
*/
int gprs_rlcmac_tbf::assemble_forward_llc(uint8_t *data, uint8_t len)
{
struct rlc_ul_header *rh = (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, "Too many frames in "
"block\n");
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, "UL DATA TBF=%d "
"ignored, because M='0' and E='0'.\n",
this->tfi);
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, "UL DATA TLLI out of "
"frame border\n");
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, "UL DATA PFI out of "
"frame border\n");
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, "UL DATA TBF=%d ignored, "
"because LI delimits data that exceeds block size.\n",
this->tfi);
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];
}
LOGP(DRLCMACUL, LOGL_DEBUG, "-- Appending chunk (len=%d) to "
"frame at %d.\n", chunk, this->llc_index);
if (this->llc_index + chunk > LLC_MAX_LEN) {
LOGP(DRLCMACUL, LOGL_NOTICE, "LLC frame exceeds "
"maximum size.\n");
chunk = LLC_MAX_LEN - this->llc_index;
}
memcpy(this->llc_frame + this->llc_index, data + frame_offset[i],
chunk);
this->llc_index += chunk;
/* not last frame. */
if (i != frames - 1) {
/* send frame to SGSN */
LOGP(DRLCMACUL, LOGL_INFO, "Complete UL frame for "
"TBF=%d: len=%d\n", this->tfi, this->llc_index);
gprs_rlcmac_tx_ul_ud(this);
this->llc_index = 0; /* reset frame space */
/* 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, "Complete UL frame for "
"TBF=%d that fits precisely in last block: "
"len=%d\n", this->tfi, this->llc_index);
gprs_rlcmac_tx_ul_ud(this);
this->llc_index = 0; /* reset frame space */
}
}
return 0;
}
void gprs_rlcmac_tbf::free_all(struct gprs_rlcmac_trx *trx)
{
for (uint8_t tfi = 0; tfi < 32; tfi++) {

3
src/tbf.h
View File

@ -96,6 +96,9 @@ struct gprs_rlcmac_tbf {
struct msgb *llc_dequeue(bssgp_bvc_ctx *bctx);
void update_llc_frame(struct msgb *msg);
/* TODO: extract LLC class? */
int assemble_forward_llc(uint8_t *data, uint8_t len);
int rlcmac_diag();
struct llist_head list;