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osmo-pcu/src/gprs_rlcmac_data.cpp

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/* Data block transfer
*
* 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 <gprs_bssgp_pcu.h>
#include <gprs_rlcmac.h>
#include <pcu_l1_if.h>
extern "C" {
int bssgp_tx_llc_discarded(struct bssgp_bvc_ctx *bctx, uint32_t tlli,
uint8_t num_frames, uint32_t num_octets);
}
/* 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 10
/* If acknowledgement to uplink/downlin assignmentshould be polled */
#define POLLING_ASSIGNMENT 0
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));
}
int gprs_rlcmac_poll_timeout(struct gprs_rlcmac_tbf *tbf)
{
LOGP(DRLCMAC, LOGL_NOTICE, "Poll timeout for %s TBF=%d\n",
(tbf->direction == GPRS_RLCMAC_UL_TBF) ? "UL" : "DL", tbf->tfi);
tbf->poll_state = GPRS_RLCMAC_POLL_NONE;
if (tbf->ul_ack_state == GPRS_RLCMAC_UL_ACK_WAIT_ACK) {
LOGP(DRLCMAC, LOGL_NOTICE, "- Timeout for polling PACKET "
"CONTROL ACK for PACKET UPLINK ACK\n");
tbf->ul_ack_state = GPRS_RLCMAC_UL_ACK_NONE;
if (tbf->state == GPRS_RLCMAC_FINISHED) {
struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
tbf->dir.ul.n3103++;
if (tbf->dir.ul.n3103 == bts->n3103) {
LOGP(DRLCMAC, LOGL_NOTICE,
"- N3103 exceeded\n");
tbf_new_state(tbf, GPRS_RLCMAC_RELEASING);
tbf_timer_start(tbf, 3169, bts->t3169, 0);
return 0;
}
/* reschedule UL ack */
tbf->ul_ack_state = GPRS_RLCMAC_UL_ACK_SEND_ACK;
}
} else
if (tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_WAIT_ACK) {
LOGP(DRLCMAC, LOGL_NOTICE, "- Timeout for polling PACKET "
"CONTROL ACK for PACKET UPLINK ASSIGNMENT.\n");
tbf->ul_ass_state = GPRS_RLCMAC_UL_ASS_NONE;
} else
if (tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_WAIT_ACK) {
LOGP(DRLCMAC, LOGL_NOTICE, "- Timeout for polling PACKET "
"CONTROL ACK for PACKET DOWNLINK ASSIGNMENT.\n");
tbf->dl_ass_state = GPRS_RLCMAC_DL_ASS_NONE;
/* in case out downlink assigment failed: */
if (tbf->state == GPRS_RLCMAC_ASSIGN) {
LOGP(DRLCMAC, LOGL_NOTICE, "- Assignment failed\n");
tbf_free(tbf);
}
} else
if (tbf->direction == GPRS_RLCMAC_DL_TBF)
{
struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
LOGP(DRLCMAC, LOGL_NOTICE, "- Timeout for polling PACKET "
" DOWNLINK ACK.\n");
tbf->dir.dl.n3105++;
if (tbf->dir.dl.n3105 == bts->n3105) {
LOGP(DRLCMAC, LOGL_NOTICE, "- N3105 exceeded\n");
tbf_new_state(tbf, GPRS_RLCMAC_RELEASING);
tbf_timer_start(tbf, 3195, bts->t3195, 0);
return 0;
}
} else
LOGP(DRLCMAC, LOGL_ERROR, "- Poll Timeout, but no event!\n");
return 0;
}
/* Received Uplink RLC control block. */
int gprs_rlcmac_rcv_control_block(bitvec *rlc_block, uint8_t trx, uint8_t ts,
uint32_t fn)
{
struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
int8_t tfi = 0; /* must be signed */
uint32_t tlli = 0;
struct gprs_rlcmac_tbf *tbf;
int rc;
RlcMacUplink_t * ul_control_block = (RlcMacUplink_t *)malloc(sizeof(RlcMacUplink_t));
LOGP(DRLCMAC, LOGL_DEBUG, "+++++++++++++++++++++++++ RX : Uplink Control Block +++++++++++++++++++++++++\n");
decode_gsm_rlcmac_uplink(rlc_block, ul_control_block);
LOGPC(DCSN1, LOGL_NOTICE, "\n");
LOGP(DRLCMAC, LOGL_DEBUG, "------------------------- RX : Uplink Control Block -------------------------\n");
switch (ul_control_block->u.MESSAGE_TYPE) {
case MT_PACKET_CONTROL_ACK:
tlli = ul_control_block->u.Packet_Control_Acknowledgement.TLLI;
tbf = tbf_by_poll_fn(fn, trx, ts);
if (!tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "PACKET CONTROL ACK with "
"unknown FN=%u TLL=0x%08x (TRX %d TS %d)\n",
fn, tlli, trx, ts);
break;
}
tfi = tbf->tfi;
if (tlli != tbf->tlli) {
LOGP(DRLCMAC, LOGL_INFO, "Phone changed TLLI to "
"0x%08x\n", tlli);
tbf->tlli = tlli;
}
LOGP(DRLCMAC, LOGL_DEBUG, "RX: [PCU <- BTS] TFI: %u TLLI: 0x%08x Packet Control Ack\n", tbf->tfi, tbf->tlli);
tbf->poll_state = GPRS_RLCMAC_POLL_NONE;
/* check if this control ack belongs to packet uplink ack */
if (tbf->ul_ack_state == GPRS_RLCMAC_UL_ACK_WAIT_ACK) {
LOGP(DRLCMAC, LOGL_DEBUG, "TBF: [UPLINK] END TFI: %u TLLI: 0x%08x \n", tbf->tfi, tbf->tlli);
tbf->ul_ack_state = GPRS_RLCMAC_UL_ACK_NONE;
tbf_free(tbf);
break;
}
if (tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_WAIT_ACK) {
LOGP(DRLCMAC, LOGL_DEBUG, "TBF: [UPLINK] DOWNLINK ASSIGNED TFI: %u TLLI: 0x%08x \n", tbf->tfi, tbf->tlli);
tbf->dl_ass_state = GPRS_RLCMAC_DL_ASS_NONE;
break;
}
if (tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_WAIT_ACK) {
LOGP(DRLCMAC, LOGL_DEBUG, "TBF: [DOWNLINK] UPLINK ASSIGNED TFI: %u TLLI: 0x%08x \n", tbf->tfi, tbf->tlli);
tbf->ul_ass_state = GPRS_RLCMAC_UL_ASS_NONE;
break;
}
LOGP(DRLCMAC, LOGL_ERROR, "Error: received PACET CONTROL ACK "
"at no request\n");
break;
case MT_PACKET_DOWNLINK_ACK_NACK:
tfi = ul_control_block->u.Packet_Downlink_Ack_Nack.DOWNLINK_TFI;
tbf = tbf_by_poll_fn(fn, trx, ts);
if (!tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "PACKET DOWNLINK ACK with "
"unknown FN=%u TBF=%d (TRX %d TS %d)\n",
fn, tfi, trx, ts);
break;
}
/* reset N3105 */
tbf->dir.dl.n3105 = 0;
/* stop timer T3191 */
tbf_timer_stop(tbf);
tlli = tbf->tlli;
LOGP(DRLCMAC, LOGL_DEBUG, "RX: [PCU <- BTS] TFI: %u TLLI: 0x%08x Packet Downlink Ack/Nack\n", tbf->tfi, tbf->tlli);
tbf->poll_state = GPRS_RLCMAC_POLL_NONE;
rc = gprs_rlcmac_downlink_ack(tbf,
ul_control_block->u.Packet_Downlink_Ack_Nack.Ack_Nack_Description.FINAL_ACK_INDICATION,
ul_control_block->u.Packet_Downlink_Ack_Nack.Ack_Nack_Description.STARTING_SEQUENCE_NUMBER,
ul_control_block->u.Packet_Downlink_Ack_Nack.Ack_Nack_Description.RECEIVED_BLOCK_BITMAP);
if (rc == 1) {
tbf_free(tbf);
break;
}
/* check for channel request */
if (ul_control_block->u.Packet_Downlink_Ack_Nack.Exist_Channel_Request_Description) {
uint8_t trx, ts;
struct gprs_rlcmac_tbf *ul_tbf;
LOGP(DRLCMAC, LOGL_DEBUG, "MS requests UL TBF in ack "
"message, so we provide one:\n");
uplink_request:
/* create new TBF, use sme TRX as DL TBF */
tfi = tfi_alloc(GPRS_RLCMAC_UL_TBF, &trx, &ts, tbf->trx, tbf->first_ts);
if (tfi < 0) {
LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n");
/* FIXME: send reject */
break;
}
/* use multislot class of downlink TBF */
ul_tbf = tbf_alloc(tbf, GPRS_RLCMAC_UL_TBF, tfi, trx,
ts, tbf->ms_class, 0);
if (!ul_tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n");
/* FIXME: send reject */
break;
}
ul_tbf->tlli = tbf->tlli;
ul_tbf->tlli_valid = 1; /* no contention resolution */
ul_tbf->contention_resolution_done = 1;
ul_tbf->ta = tbf->ta; /* use current TA */
tbf_new_state(ul_tbf, GPRS_RLCMAC_FLOW);
tbf_timer_start(ul_tbf, 3169, bts->t3169, 0);
/* schedule uplink assignment */
tbf->ul_ass_state = GPRS_RLCMAC_UL_ASS_SEND_ASS;
}
break;
case MT_PACKET_RESOURCE_REQUEST:
if (ul_control_block->u.Packet_Resource_Request.ID.UnionType) {
tlli = ul_control_block->u.Packet_Resource_Request.ID.u.TLLI;
tbf = tbf_by_tlli(tlli, GPRS_RLCMAC_UL_TBF);
if (!tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "PACKET RESSOURCE REQ unknown uplink TLLI=0x%08x\n", tlli);
break;
}
tfi = tbf->tfi;
} else {
if (ul_control_block->u.Packet_Resource_Request.ID.u.Global_TFI.UnionType) {
tfi = ul_control_block->u.Packet_Resource_Request.ID.u.Global_TFI.u.DOWNLINK_TFI;
tbf = tbf_by_tfi(tfi, trx, ts, GPRS_RLCMAC_DL_TBF);
if (!tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "PACKET RESSOURCE REQ unknown downlink TBF=%d\n", tlli);
break;
}
} else {
tfi = ul_control_block->u.Packet_Resource_Request.ID.u.Global_TFI.u.UPLINK_TFI;
tbf = tbf_by_tfi(tfi, trx, ts, GPRS_RLCMAC_UL_TBF);
if (!tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "PACKET RESSOURCE REQ unknown uplink TBF=%d\n", tlli);
break;
}
}
tlli = tbf->tlli;
}
LOGP(DRLCMAC, LOGL_ERROR, "RX: [PCU <- BTS] %s TFI: %u TLLI: 0x%08x FIXME: Packet ressource request\n", (tbf->direction == GPRS_RLCMAC_UL_TBF) ? "UL" : "DL", tbf->tfi, tbf->tlli);
break;
default:
LOGP(DRLCMAC, LOGL_NOTICE, "RX: [PCU <- BTS] unknown control block received\n");
}
free(ul_control_block);
return 1;
}
#ifdef DEBUG_DL_ASS_IDLE
char debug_imsi[16];
#endif
void tbf_timer_cb(void *_tbf)
{
struct gprs_rlcmac_tbf *tbf = (struct gprs_rlcmac_tbf *)_tbf;
LOGP(DRLCMAC, LOGL_DEBUG, "%s TBF=%d timer %u expired.\n",
(tbf->direction == GPRS_RLCMAC_UL_TBF) ? "UL" : "DL", tbf->tfi,
tbf->T);
tbf->num_T_exp++;
switch (tbf->T) {
#ifdef DEBUG_DL_ASS_IDLE
case 1234:
gprs_rlcmac_trigger_downlink_assignment(tbf, 0, debug_imsi);
break;
#endif
case 0: /* assignment */
/* change state to FLOW, so scheduler will start transmission */
if (tbf->state == GPRS_RLCMAC_ASSIGN) {
tbf_new_state(tbf, GPRS_RLCMAC_FLOW);
tbf_assign_control_ts(tbf);
} else
LOGP(DRLCMAC, LOGL_ERROR, "Error: TBF is not in assign "
"state\n");
break;
case 3169:
case 3191:
case 3195:
LOGP(DRLCMAC, LOGL_NOTICE, "TBF T%d timeout during "
"transsmission\n", tbf->T);
/* fall through */
case 3193:
LOGP(DRLCMAC, LOGL_DEBUG, "TBF will be freed due to timeout\n");
/* free TBF */
tbf_free(tbf);
break;
default:
LOGP(DRLCMAC, LOGL_ERROR, "Timer expired in unknown mode: %u\n",
tbf->T);
}
}
/*
* 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;
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;
}
*tlli = ntohl(*((uint32_t *)data));
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)
{
int final = (tbf->state == GPRS_RLCMAC_FINISHED);
struct msgb *msg;
if (final && tbf->poll_state != GPRS_RLCMAC_POLL_NONE) {
LOGP(DRLCMACUL, LOGL_DEBUG, "Polling is already "
"sheduled for TBF=%d, so we must wait for final uplink "
"ack...\n", tbf->tfi);
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 *)malloc(sizeof(RlcMacDownlink_t));
write_packet_uplink_ack(mac_control_block, tbf, final);
encode_gsm_rlcmac_downlink(ack_vec, mac_control_block);
bitvec_pack(ack_vec, msgb_put(msg, 23));
bitvec_free(ack_vec);
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 aknowledged. */
tbf->contention_resolution_done = 1;
if (final) {
tbf->poll_state = GPRS_RLCMAC_POLL_SCHED;
tbf->poll_fn = (fn + 13) % 2715648;
/* waiting for final acknowledge */
tbf->ul_ack_state = GPRS_RLCMAC_UL_ACK_WAIT_ACK;
} else
tbf->ul_ack_state = GPRS_RLCMAC_UL_ACK_NONE;
return msg;
}
/* receive UL data block
*
* The blocks are defragmented and forwarded as LLC frames, if complete.
*/
int gprs_rlcmac_rcv_data_block_acknowledged(uint8_t trx, uint8_t ts,
uint8_t *data, uint8_t len)
{
struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
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(rh->tfi, trx, ts, GPRS_RLCMAC_UL_TBF);
if (!tbf) {
LOGP(DRLCMACUL, LOGL_NOTICE, "UL DATA unknown TBF=%d\n",
rh->tfi);
return 0;
}
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);
/* get TLLI */
if (!tbf->tlli_valid) {
/* 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;
}
tbf->tlli_valid = 1;
LOGP(DRLCMACUL, LOGL_INFO, "Decoded premier TLLI=0x%08x of "
"UL DATA TBF=%d.\n", tbf->tlli, rh->tfi);
/* 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 == 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 == 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 == 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) {
/* 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)
{
struct msgb *msg;
struct gprs_rlcmac_tbf *new_tbf;
#if POLLING_ASSIGNMENT == 1
if (tbf->poll_state != GPRS_RLCMAC_POLL_NONE) {
LOGP(DRLCMACUL, LOGL_DEBUG, "Polling is already "
"sheduled for TBF=%d, so we must wait for uplink "
"assignment...\n", tbf->tfi);
return NULL;
}
#endif
/* on down TBF we get the uplink TBF to be assigned. */
if (tbf->direction == GPRS_RLCMAC_DL_TBF)
new_tbf = tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_UL_TBF);
else
new_tbf = tbf;
if (!new_tbf) {
LOGP(DRLCMACUL, LOGL_ERROR, "We have a schedule for uplink "
"assignment at downlink TBF=%d, but there is no uplink "
"TBF\n", tbf->tfi);
tbf->ul_ass_state = GPRS_RLCMAC_UL_ASS_NONE;
return NULL;
}
msg = msgb_alloc(23, "rlcmac_ul_ass");
if (!msg)
return NULL;
LOGP(DRLCMAC, LOGL_INFO, "TBF: START TFI: %u TLLI: 0x%08x Packet Uplink Assignment (PACCH)\n", new_tbf->tfi, new_tbf->tlli);
bitvec *ass_vec = bitvec_alloc(23);
if (!ass_vec) {
msgb_free(msg);
return NULL;
}
bitvec_unhex(ass_vec,
"2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
write_packet_uplink_assignment(ass_vec, tbf->tfi,
(tbf->direction == GPRS_RLCMAC_DL_TBF), 0, 0, new_tbf,
POLLING_ASSIGNMENT);
bitvec_pack(ass_vec, msgb_put(msg, 23));
RlcMacDownlink_t * mac_control_block = (RlcMacDownlink_t *)malloc(sizeof(RlcMacDownlink_t));
LOGP(DRLCMAC, LOGL_DEBUG, "+++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++\n");
decode_gsm_rlcmac_downlink(ass_vec, mac_control_block);
LOGPC(DCSN1, LOGL_NOTICE, "\n");
LOGP(DRLCMAC, LOGL_DEBUG, "------------------------- TX : Packet Uplink Assignment -------------------------\n");
bitvec_free(ass_vec);
#if POLLING_ASSIGNMENT == 1
FIXME process does not work, also the acknowledgement is not checked.
tbf->poll_state = GPRS_RLCMAC_POLL_SCHED;
tbf->poll_fn = (fn + 13) % 2715648;
tbf->ul_ass_state = GPRS_RLCMAC_UL_ASS_WAIT_ACK;
#else
tbf->ul_ass_state = GPRS_RLCMAC_UL_ASS_NONE;
#endif
return msg;
}
int gprs_rlcmac_rcv_rach(uint8_t ra, uint32_t Fn, int16_t qta)
{
struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
struct gprs_rlcmac_tbf *tbf;
uint8_t trx, ts;
int8_t tfi; /* must be signed */
LOGP(DRLCMAC, LOGL_DEBUG, "MS requests UL TBF on RACH, so we provide "
"one:\n");
// Create new TBF
tfi = tfi_alloc(GPRS_RLCMAC_UL_TBF, &trx, &ts, -1, -1);
if (tfi < 0) {
LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n");
/* FIXME: send reject */
return -EBUSY;
}
/* set class to 0, since we don't know the multislot class yet */
tbf = tbf_alloc(NULL, GPRS_RLCMAC_UL_TBF, tfi, trx, ts, 0, 1);
if (!tbf) {
LOGP(DRLCMAC, LOGL_NOTICE, "No PDCH ressource\n");
/* FIXME: send reject */
return -EBUSY;
}
if (qta < 0)
qta = 0;
if (qta > 252)
qta = 252;
tbf->ta = qta >> 2;
tbf_new_state(tbf, GPRS_RLCMAC_FLOW);
tbf_timer_start(tbf, 3169, bts->t3169, 0);
LOGP(DRLCMAC, LOGL_DEBUG, "TBF: [UPLINK] START TFI: %u\n", tbf->tfi);
LOGP(DRLCMAC, LOGL_DEBUG, "RX: [PCU <- BTS] TFI: %u RACH qbit-ta=%d ra=%d, Fn=%d (%d,%d,%d)\n", tbf->tfi, qta, ra, Fn, (Fn / (26 * 51)) % 32, Fn % 51, Fn % 26);
LOGP(DRLCMAC, LOGL_INFO, "TX: START TFI: %u Immediate Assignment Uplink (AGCH)\n", tbf->tfi);
bitvec *immediate_assignment = bitvec_alloc(22) /* without plen */;
bitvec_unhex(immediate_assignment, "2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
int plen = write_immediate_assignment(immediate_assignment, 0, ra, Fn, tbf->ta, tbf->arfcn, tbf->first_ts, tbf->tsc, tbf->tfi, tbf->dir.ul.usf[tbf->first_ts], 0, 0, 0);
pcu_l1if_tx_agch(immediate_assignment, plen);
bitvec_free(immediate_assignment);
return 0;
}
/*
* DL data block flow
*/
static struct msgb *llc_dequeue(struct gprs_rlcmac_tbf *tbf)
{
struct msgb *msg;
struct timeval *tv, tv_now;
uint32_t octets = 0, frames = 0;
gettimeofday(&tv_now, NULL);
while ((msg = msgb_dequeue(&tbf->llc_queue))) {
tv = (struct timeval *)msg->data;
msgb_pull(msg, sizeof(*tv));
if (tv->tv_sec /* not infinite */
&& (tv_now.tv_sec > tv->tv_sec /* and secs expired */
|| (tv_now.tv_sec == tv->tv_sec /* .. or if secs equal .. */
&& tv_now.tv_usec > tv->tv_usec))) { /* .. usecs expired */
LOGP(DRLCMACDL, LOGL_NOTICE, "Discarding LLC PDU of "
"DL TBF=%d, because lifetime limit reached\n",
tbf->tfi);
frames++;
octets += msg->len;
msgb_free(msg);
continue;
}
break;
}
if (frames) {
if (frames > 0xff)
frames = 0xff;
if (octets > 0xffffff)
octets = 0xffffff;
bssgp_tx_llc_discarded(bctx, tbf->tlli, frames, octets);
}
return msg;
}
/* send DL data block
*
* The messages are fragmented and forwarded as data blocks.
*/
struct msgb *gprs_rlcmac_send_data_block_acknowledged(
struct gprs_rlcmac_tbf *tbf, uint32_t fn, uint8_t ts)
{
struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
struct rlc_dl_header *rh;
struct rlc_li_field *li;
uint8_t block_length; /* total length of block, including spare bits */
uint8_t block_data; /* usable data of block, w/o spare bits, inc. MAC */
struct msgb *msg, *dl_msg;
uint8_t bsn;
uint16_t mod_sns = tbf->sns - 1;
uint16_t mod_sns_half = (tbf->sns >> 1) - 1;
uint16_t index;
uint8_t *delimiter, *data, *e_pointer;
uint8_t len;
uint16_t space, chunk;
LOGP(DRLCMACDL, LOGL_DEBUG, "DL DATA TBF=%d downlink (V(A)==%d .. "
"V(S)==%d)\n", tbf->tfi, tbf->dir.dl.v_a, tbf->dir.dl.v_s);
do_resend:
/* check if there is a block with negative acknowledgement */
for (bsn = tbf->dir.dl.v_a; bsn != tbf->dir.dl.v_s;
bsn = (bsn + 1) & mod_sns) {
index = (bsn & mod_sns_half);
if (tbf->dir.dl.v_b[index] == 'N'
|| tbf->dir.dl.v_b[index] == 'X') {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Resending BSN %d\n",
bsn);
/* re-send block with negative aknowlegement */
tbf->dir.dl.v_b[index] = 'U'; /* unacked */
goto tx_block;
}
}
/* if the window has stalled, or transfer is complete,
* send an unacknowledged block */
if (tbf->state == GPRS_RLCMAC_FINISHED
|| ((tbf->dir.dl.v_s - tbf->dir.dl.v_a) & mod_sns) == tbf->ws) {
int resend = 0;
if (tbf->state == GPRS_RLCMAC_FINISHED)
LOGP(DRLCMACDL, LOGL_DEBUG, "- Restarting at BSN %d, "
"because all blocks have been transmitted.\n",
tbf->dir.dl.v_a);
else
LOGP(DRLCMACDL, LOGL_NOTICE, "- Restarting at BSN %d, "
"because all window is stalled.\n",
tbf->dir.dl.v_a);
/* 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 (tbf->dir.dl.v_s == tbf->dir.dl.v_a) {
LOGP(DRLCMACDL, LOGL_ERROR, "- MS acked all block, "
"but we still transmitting!\n");
/* we just send final block again */
index = ((tbf->dir.dl.v_s - 1) & mod_sns_half);
goto tx_block;
}
/* cycle through all unacked blocks */
for (bsn = tbf->dir.dl.v_a; bsn != tbf->dir.dl.v_s;
bsn = (bsn + 1) & mod_sns) {
index = (bsn & mod_sns_half);
if (tbf->dir.dl.v_b[index] == 'U') {
/* mark to be re-send */
tbf->dir.dl.v_b[index] = 'X';
resend++;
}
}
/* At this point there should be at leasst 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 */
index = ((tbf->dir.dl.v_s - 1) & mod_sns_half);
goto tx_block;
}
goto do_resend;
}
LOGP(DRLCMACDL, LOGL_DEBUG, "- Sending new block at BSN %d\n",
tbf->dir.dl.v_s);
/* now we still have untransmitted LLC data, so we fill mac block */
index = tbf->dir.dl.v_s & mod_sns_half;
data = tbf->rlc_block[index];
switch (bts->initial_cs) {
case 2: /* CS-2 */
block_length = 34;
block_data = 33;
break;
case 3: /* CS-3 */
block_length = 40;
block_data = 39;
break;
case 4: /* CS-4 */
block_length = 54;
block_data = 53;
break;
default: /* CS-1 */
block_length = 23;
block_data = 23;
}
memset(data, 0x2b, block_data); /* spare bits will be left 0 */
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 = tbf->tfi; /* TFI */
rh->fbi = 0; /* Final Block Indicator, set late, if true */
rh->bsn = tbf->dir.dl.v_s; /* Block Sequence Number */
rh->e = 0; /* Extension bit, maybe set later */
e_pointer = data + 2; /* points to E of current chunk */
data += 3;
delimiter = data; /* where next length header would be stored */
space = block_data - 3;
while (1) {
chunk = tbf->llc_length - tbf->llc_index;
/* 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 */
memcpy(data, tbf->llc_frame + tbf->llc_index, space);
/* incement index */
tbf->llc_index += space;
/* return data block as message */
break;
}
/* if FINAL chunk would fit precisely in space left */
if (chunk == space && llist_empty(&tbf->llc_queue)) {
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 "
"TBF=%d that fits precisely in last block: "
"len=%d\n", tbf->tfi, tbf->llc_length);
/* block is filled, so there is no extension */
*e_pointer |= 0x01;
/* fill space */
memcpy(data, tbf->llc_frame + tbf->llc_index, space);
/* reset LLC frame */
tbf->llc_index = tbf->llc_length = 0;
/* final block */
rh->fbi = 1; /* we indicate final block */
tbf_new_state(tbf, 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)
memcpy(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 */
memcpy(data, tbf->llc_frame + tbf->llc_index, space);
/* incement index */
tbf->llc_index += 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)
memcpy(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 */
memcpy(data, tbf->llc_frame + tbf->llc_index, chunk);
data += chunk;
space -= chunk;
LOGP(DRLCMACDL, LOGL_INFO, "Complete DL frame for TBF=%d: "
"len=%d\n", tbf->tfi, tbf->llc_length);
/* reset LLC frame */
tbf->llc_index = tbf->llc_length = 0;
/* dequeue next LLC frame, if any */
msg = llc_dequeue(tbf);
if (msg) {
LOGP(DRLCMACDL, LOGL_INFO, "- Dequeue next LLC for "
"TBF=%d (len=%d)\n", tbf->tfi, msg->len);
memcpy(tbf->llc_frame, msg->data, msg->len);
tbf->llc_length = msg->len;
msgb_free(msg);
}
/* if we have more data and we have space left */
if (space > 0 && tbf->llc_length) {
li->m = 1; /* we indicate more frames to follow */
continue;
}
/* if we don't have more LLC frames */
if (!tbf->llc_length) {
LOGP(DRLCMACDL, LOGL_DEBUG, "-- Final block, so we "
"done.\n");
li->e = 1; /* we cannot extend */
rh->fbi = 1; /* we indicate final block */
tbf->dir.dl.tx_counter = POLL_ACK_AFTER_FRAMES + 1;
/* + 1 indicates: first final ack */
tbf_new_state(tbf, 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(tbf->rlc_block[index], block_length));
tbf->rlc_block_len[index] = block_length;
/* raise send state and set ack state array */
tbf->dir.dl.v_b[index] = 'U'; /* unacked */
tbf->dir.dl.v_s = (tbf->dir.dl.v_s + 1) & mod_sns; /* inc send state */
tx_block:
/* from this point on, new block is sent or old block is resent */
/* get data and header from current block */
data = tbf->rlc_block[index];
len = tbf->rlc_block_len[index];
rh = (struct rlc_dl_header *)data;
/* 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 (tbf->dir.dl.tx_counter >= POLL_ACK_AFTER_FRAMES) {
if (tbf->dir.dl.tx_counter > POLL_ACK_AFTER_FRAMES) {
/* if rx_counter is POLL_ACK_AFTER_FRAMES + 1, this
* indicates: poll caused by final ack. */
LOGP(DRLCMACDL, LOGL_DEBUG, "- Scheduling Ack/Nack "
"polling, because final block sent.\n");
} else {
LOGP(DRLCMACDL, LOGL_DEBUG, "- Scheduling Ack/Nack "
"polling, because %d blocks sent.\n",
POLL_ACK_AFTER_FRAMES);
}
tbf->dir.dl.tx_counter = 0;
/* scheduling not possible, because: */
if (tbf->poll_state != GPRS_RLCMAC_POLL_NONE)
LOGP(DRLCMAC, LOGL_DEBUG, "Polling is already "
"sheduled for TBF=%d, so we must wait for "
"requesting downlink ack\n", tbf->tfi);
else if (tbf->control_ts != ts)
LOGP(DRLCMAC, LOGL_DEBUG, "Polling cannot be "
"sheduled in this TS %d, waiting for "
"TS %d\n", ts, tbf->control_ts);
else {
LOGP(DRLCMAC, LOGL_DEBUG, "Polling sheduled in this "
"TS %d\n", ts);
/* start timer whenever we send the final block */
if (rh->fbi == 1)
tbf_timer_start(tbf, 3191, bts->t3191, 0);
/* schedule polling */
tbf->poll_state = GPRS_RLCMAC_POLL_SCHED;
tbf->poll_fn = (fn + 13) % 2715648;
/* set polling in header */
rh->rrbp = 0; /* N+13 */
rh->s_p = 1; /* Polling */
/* Increment TX-counter */
tbf->dir.dl.tx_counter++;
}
} else {
/* Increment TX-counter */
tbf->dir.dl.tx_counter++;
}
/* return data block as message */
dl_msg = msgb_alloc(len, "rlcmac_dl_data");
if (!dl_msg)
return NULL;
memcpy(msgb_put(dl_msg, len), data, len);
return dl_msg;
}
int gprs_rlcmac_downlink_ack(struct gprs_rlcmac_tbf *tbf, uint8_t final,
uint8_t ssn, uint8_t *rbb)
{
char show_rbb[65], show_v_b[RLC_MAX_SNS + 1];
uint16_t mod_sns = tbf->sns - 1;
uint16_t mod_sns_half = (tbf->sns >> 1) - 1;
int i; /* must be signed */
int16_t dist; /* must be signed */
uint8_t bit;
uint16_t bsn;
struct msgb *msg;
LOGP(DRLCMACDL, LOGL_DEBUG, "TBF=%d downlink acknowledge\n",
tbf->tfi);
if (!final) {
/* show received array in debug (bit 64..1) */
for (i = 63; i >= 0; i--) {
bit = (rbb[i >> 3] >> (7 - (i&7))) & 1;
show_rbb[i] = (bit) ? '1' : 'o';
}
show_rbb[64] = '\0';
LOGP(DRLCMACDL, LOGL_DEBUG, "- ack: (BSN=%d)\"%s\""
"(BSN=%d) 1=ACK o=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 = (tbf->dir.dl.v_s - ssn) & mod_sns;
/* check if distance is less than distance V(A)..V(S) */
if (dist < ((tbf->dir.dl.v_s - tbf->dir.dl.v_a) & mod_sns)) {
/* SSN - 1 is in range V(A)..V(S)-1 */
for (i = 63, bsn = (ssn - 1) & mod_sns;
i >= 0 && bsn != ((tbf->dir.dl.v_a - 1) & mod_sns);
i--, bsn = (bsn - 1) & mod_sns) {
bit = (rbb[i >> 3] >> (7 - (i&7))) & 1;
if (bit) {
LOGP(DRLCMACDL, LOGL_DEBUG, "- got "
"ack for BSN=%d\n", bsn);
tbf->dir.dl.v_b[bsn & mod_sns_half]
= 'A';
} else {
LOGP(DRLCMACDL, LOGL_DEBUG, "- got "
"NACK for BSN=%d\n", bsn);
tbf->dir.dl.v_b[bsn & mod_sns_half]
= 'N';
}
}
} else {
/* 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 (DL TBF=%d) Free TFB!\n",
tbf->tfi);
return 1; /* indicate to free TBF */
}
/* raise V(A), if possible */
for (i = 0, bsn = tbf->dir.dl.v_a; bsn != tbf->dir.dl.v_s;
i++, bsn = (bsn + 1) & mod_sns) {
if (tbf->dir.dl.v_b[bsn & mod_sns_half] == 'A') {
tbf->dir.dl.v_b[bsn & mod_sns_half] = 'I';
/* mark invalid */
tbf->dir.dl.v_a = (tbf->dir.dl.v_a + 1)
& mod_sns;
} else
break;
}
/* show receive state array in debug (V(A)..V(S)-1) */
for (i = 0, bsn = tbf->dir.dl.v_a; bsn != tbf->dir.dl.v_s;
i++, bsn = (bsn + 1) & mod_sns) {
show_v_b[i] = tbf->dir.dl.v_b[bsn & mod_sns_half];
if (show_v_b[i] == 0)
show_v_b[i] = ' ';
}
show_v_b[i] = '\0';
LOGP(DRLCMACDL, LOGL_DEBUG, "- V(B): (V(A)=%d)\"%s\""
"(V(S)-1=%d) A=Acked N=Nacked U=Unacked "
"X=Resend-Unacked\n", tbf->dir.dl.v_a, show_v_b,
(tbf->dir.dl.v_s - 1) & mod_sns);
if (tbf->state == GPRS_RLCMAC_FINISHED
&& tbf->dir.dl.v_s == tbf->dir.dl.v_a) {
LOGP(DRLCMACDL, LOGL_NOTICE, "Received final block, "
"but without final ack inidcation\n");
} else
return 0;
} else
LOGP(DRLCMACDL, LOGL_DEBUG, "- Final ACK received.\n");
/* check for LLC PDU in the LLC Queue */
msg = llc_dequeue(tbf);
if (!msg) {
struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
/* no message, start T3193, change state to RELEASE */
LOGP(DRLCMACDL, LOGL_DEBUG, "- No new message, so we "
"release.\n");
/* start T3193 */
tbf_timer_start(tbf, 3193, bts->t3193_msec / 1000,
bts->t3193_msec & 1000);
tbf_new_state(tbf, GPRS_RLCMAC_WAIT_RELEASE);
return 0;
}
memcpy(tbf->llc_frame, msg->data, msg->len);
tbf->llc_length = msg->len;
msgb_free(msg);
/* we have a message, so we trigger downlink assignment, and there
* set the state to ASSIGN. also we set old_downlink, because we
* re-use this tbf. */
LOGP(DRLCMAC, LOGL_DEBUG, "Trigger dowlink assignment on PACCH, "
"because another LLC PDU has arrived in between\n");
memset(&tbf->dir.dl, 0, sizeof(tbf->dir.dl)); /* reset RLC states */
tbf_update(tbf);
gprs_rlcmac_trigger_downlink_assignment(tbf, 1, NULL);
return 0;
}
struct msgb *gprs_rlcmac_send_packet_downlink_assignment(
struct gprs_rlcmac_tbf *tbf, uint32_t fn)
{
struct msgb *msg;
struct gprs_rlcmac_tbf *new_tbf;
#if POLLING_ASSIGNMENT == 1
if (tbf->poll_state != GPRS_RLCMAC_POLL_NONE) {
LOGP(DRLCMAC, LOGL_DEBUG, "Polling is already "
"sheduled for TBF=%d, so we must wait for downlink "
"assignment...\n", tbf->tfi);
return NULL;
}
#endif
/* on uplink TBF we get the downlink TBF to be assigned. */
if (tbf->direction == GPRS_RLCMAC_UL_TBF) {
/* be sure to check first, if contention resolution is done,
* otherwise we cannot send the assignment yet */
if (!tbf->contention_resolution_done) {
LOGP(DRLCMAC, LOGL_NOTICE, "Cannot assign DL TBF now, "
"because contention resolution is not "
"finished.\n");
return NULL;
}
new_tbf = tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_DL_TBF);
} else
new_tbf = tbf;
if (!new_tbf) {
LOGP(DRLCMACDL, LOGL_ERROR, "We have a schedule for downlink "
"assignment at uplink TBF=%d, but there is no downlink "
"TBF\n", tbf->tfi);
tbf->dl_ass_state = GPRS_RLCMAC_DL_ASS_NONE;
return NULL;
}
msg = msgb_alloc(23, "rlcmac_dl_ass");
if (!msg)
return NULL;
bitvec *ass_vec = bitvec_alloc(23);
if (!ass_vec) {
msgb_free(msg);
return NULL;
}
bitvec_unhex(ass_vec,
"2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
LOGP(DRLCMAC, LOGL_INFO, "TBF: START TFI: %u TLLI: 0x%08x Packet Downlink Assignment (PACCH)\n", new_tbf->tfi, new_tbf->tlli);
RlcMacDownlink_t * mac_control_block = (RlcMacDownlink_t *)malloc(sizeof(RlcMacDownlink_t));
write_packet_downlink_assignment(mac_control_block, tbf->tfi,
(tbf->direction == GPRS_RLCMAC_DL_TBF), new_tbf,
POLLING_ASSIGNMENT);
LOGP(DRLCMAC, LOGL_DEBUG, "+++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++\n");
encode_gsm_rlcmac_downlink(ass_vec, mac_control_block);
LOGPC(DCSN1, LOGL_NOTICE, "\n");
LOGP(DRLCMAC, LOGL_DEBUG, "------------------------- TX : Packet Downlink Assignment -------------------------\n");
bitvec_pack(ass_vec, msgb_put(msg, 23));
bitvec_free(ass_vec);
free(mac_control_block);
#if POLLING_ASSIGNMENT == 1
tbf->poll_state = GPRS_RLCMAC_POLL_SCHED;
tbf->poll_fn = (fn + 13) % 2715648;
tbf->dl_ass_state = GPRS_RLCMAC_DL_ASS_WAIT_ACK;
#else
tbf->dl_ass_state = GPRS_RLCMAC_DL_ASS_NONE;
#endif
return msg;
}
static void gprs_rlcmac_downlink_assignment(gprs_rlcmac_tbf *tbf, uint8_t poll,
char *imsi)
{
LOGP(DRLCMAC, LOGL_INFO, "TX: START TFI: %u TLLI: 0x%08x Immediate Assignment Downlink (PCH)\n", tbf->tfi, tbf->tlli);
bitvec *immediate_assignment = bitvec_alloc(22); /* without plen */
bitvec_unhex(immediate_assignment, "2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
/* use request reference that has maximum distance to current time,
* so the assignment will not conflict with possible RACH requests. */
int plen = write_immediate_assignment(immediate_assignment, 1, 125, (tbf->pdch[tbf->first_ts]->last_rts_fn + 21216) % 2715648, tbf->ta, tbf->arfcn, tbf->first_ts, tbf->tsc, tbf->tfi, 0, tbf->tlli, poll, tbf->poll_fn);
pcu_l1if_tx_pch(immediate_assignment, plen, imsi);
bitvec_free(immediate_assignment);
}
/* depending on the current TBF, we assign on PACCH or AGCH */
void gprs_rlcmac_trigger_downlink_assignment(gprs_rlcmac_tbf *tbf,
uint8_t old_downlink, char *imsi)
{
gprs_rlcmac_tbf *old_tbf;
#ifdef DEBUG_DL_ASS_IDLE
strncpy(debug_imsi, imsi);
LOGP(DRLCMAC, LOGL_ERROR, "**** DEBUGGING DOWNLINK ASSIGNMENT ****\n");
#endif
/* stop pending timer */
tbf_timer_stop(tbf);
/* check for downlink tbf: */
if (old_downlink)
old_tbf = tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_DL_TBF);
else
old_tbf = tbf_by_tlli(tbf->tlli, GPRS_RLCMAC_UL_TBF);
if (old_tbf && (old_tbf->state != GPRS_RLCMAC_FINISHED ||
old_tbf->ul_ack_state != GPRS_RLCMAC_UL_ACK_WAIT_ACK)) {
#ifdef DEBUG_DL_ASS_IDLE
LOGP(DRLCMAC, LOGL_ERROR, "We must wait for current TBF to be "
"released.\n");
/* wait one second until assignment */
tbf_timer_start(tbf, 1234, 1,0);
#else
LOGP(DRLCMAC, LOGL_DEBUG, "Send dowlink assignment on "
"PACCH, because %s TBF=%d exists for TLLI=0x%08x\n",
(old_tbf->direction == GPRS_RLCMAC_UL_TBF) ? "UL" : "DL",
old_tbf->tfi, old_tbf->tlli);
old_tbf->dl_ass_state = GPRS_RLCMAC_DL_ASS_SEND_ASS;
/* use TA from old TBF */
tbf->ta = old_tbf->ta;
/* change state */
tbf_new_state(tbf, GPRS_RLCMAC_ASSIGN);
/* start timer */
tbf_timer_start(tbf, 0, Tassign_pacch);
#endif
} else {
LOGP(DRLCMAC, LOGL_DEBUG, "Send dowlink assignment for TBF=%d on PCH, no TBF exist (IMSI=%s)\n", tbf->tfi, imsi);
if (!imsi || strlen(imsi) < 3) {
LOGP(DRLCMAC, LOGL_ERROR, "No valid IMSI!\n");
return;
}
/* send immediate assignment */
gprs_rlcmac_downlink_assignment(tbf, 0, imsi);
/* change state */
tbf_new_state(tbf, GPRS_RLCMAC_ASSIGN);
/* start timer */
tbf_timer_start(tbf, 0, Tassign_agch);
}
}
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