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Fixed pseudo length of IMMEDIATE ASSIGNMENT message. 

The pseudo length may not include the rest-octets, so it stays compatible
to non-GPRS phones.

At pcu_l1_if.c (OpenBTS) no pseudo length is given, so the frame is
only 22 bytes long. I could not test if it works.
This commit is contained in:
Andreas Eversberg 2012-07-05 07:38:49 +02:00
parent 1944bd5872
commit 7b0450133c
4 changed files with 24 additions and 18 deletions
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13
src/gprs_rlcmac.cpp
View File

@ -322,6 +322,7 @@ int write_immediate_assignment(bitvec * dest, uint8_t downlink, uint8_t ra,
uint8_t polling, uint32_t poll_fn)
{
unsigned wp = 0;
uint8_t plen;
bitvec_write_field(dest, wp,0x0,4); // Skip Indicator
bitvec_write_field(dest, wp,0x6,4); // Protocol Discriminator
@ -356,6 +357,13 @@ int write_immediate_assignment(bitvec * dest, uint8_t downlink, uint8_t ra,
// A zero-length LV. Just write L=0.
bitvec_write_field(dest, wp,0,8);
if ((wp % 8)) {
LOGP(DRLCMACUL, LOGL_ERROR, "Length of IMM.ASS without rest "
"octets is not multiple of 8 bits, PLEASE FIX!\n");
exit (0);
}
plen = wp / 8;
if (downlink)
{
// GSM 04.08 10.5.2.16 IA Rest Octets
@ -405,10 +413,7 @@ int write_immediate_assignment(bitvec * dest, uint8_t downlink, uint8_t ra,
bitvec_write_field(dest, wp, 0, 1); // TBF_STARTING_TIME_FLAG
}
if (wp%8)
return wp/8+1;
else
return wp/8;
return plen;
}
/* generate uplink assignment */

18
src/gprs_rlcmac_data.cpp
View File

@ -835,11 +835,11 @@ int gprs_rlcmac_rcv_rach(uint8_t ra, uint32_t Fn, int16_t qta)
tbf_timer_start(tbf, 3169, bts->t3169, 0);
LOGP(DRLCMAC, LOGL_NOTICE, "TBF: [UPLINK] START TFI: %u\n", tbf->tfi);
LOGP(DRLCMAC, LOGL_NOTICE, "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_NOTICE, "TX: [PCU -> BTS] TFI: %u Packet Immidiate Assignment\n", tbf->tfi);
bitvec *immediate_assignment = bitvec_alloc(23);
bitvec_unhex(immediate_assignment, "2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
int len = write_immediate_assignment(immediate_assignment, 0, ra, Fn, tbf->ta, tbf->arfcn, tbf->ts, tbf->tsc, tbf->tfi, usf, 0, 0, 0);
pcu_l1if_tx_agch(immediate_assignment, len);
LOGP(DRLCMAC, LOGL_NOTICE, "TX: [PCU -> BTS] TFI: %u Packet Immidiate Assignment (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->ts, tbf->tsc, tbf->tfi, usf, 0, 0, 0);
pcu_l1if_tx_agch(immediate_assignment, plen);
bitvec_free(immediate_assignment);
return 0;
@ -1325,12 +1325,12 @@ struct msgb *gprs_rlcmac_send_packet_downlink_assignment(
static void gprs_rlcmac_downlink_assignment(gprs_rlcmac_tbf *tbf, uint8_t poll)
{
LOGP(DRLCMAC, LOGL_NOTICE, "TX: [PCU -> BTS] TFI: %u TLLI: 0x%08x Immidiate Assignment (CCCH)\n", tbf->tfi, tbf->tlli);
bitvec *immediate_assignment = bitvec_alloc(23);
bitvec_unhex(immediate_assignment, "2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b2b");
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 len = write_immediate_assignment(immediate_assignment, 1, 125, (tbf->pdch->last_rts_fn + 21216) % 2715648, tbf->ta, tbf->arfcn, tbf->ts, tbf->tsc, tbf->tfi, 0, tbf->tlli, poll, tbf->poll_fn);
pcu_l1if_tx_agch(immediate_assignment, len);
int plen = write_immediate_assignment(immediate_assignment, 1, 125, (tbf->pdch->last_rts_fn + 21216) % 2715648, tbf->ta, tbf->arfcn, tbf->ts, tbf->tsc, tbf->tfi, 0, tbf->tlli, poll, tbf->poll_fn);
pcu_l1if_tx_agch(immediate_assignment, plen);
bitvec_free(immediate_assignment);
}

5
src/pcu_l1_if.cpp
View File

@ -112,7 +112,7 @@ void pcu_l1if_tx_pdtch(msgb *msg, uint8_t trx, uint8_t ts, uint16_t arfcn,
msgb_free(msg);
}
void pcu_l1if_tx_agch(bitvec * block, int len)
void pcu_l1if_tx_agch(bitvec * block, int plen)
{
struct msgb *msg = l1p_msgb_alloc();
GsmL1_Prim_t *prim = msgb_l1prim(msg);
@ -120,7 +120,8 @@ void pcu_l1if_tx_agch(bitvec * block, int len)
prim->id = GsmL1_PrimId_PhDataReq;
prim->u.phDataReq.sapi = GsmL1_Sapi_Agch;
bitvec_pack(block, prim->u.phDataReq.msgUnitParam.u8Buffer);
prim->u.phDataReq.msgUnitParam.u8Size = len;
#warning Please review, if OpenBTS requires AGCH frame without pseudo length:
prim->u.phDataReq.msgUnitParam.u8Size = 22;
osmo_wqueue_enqueue(&l1fh->udp_wq, msg);
}

6
src/sysmo_l1_if.cpp
View File

@ -140,13 +140,13 @@ void pcu_l1if_tx_ptcch(msgb *msg, uint8_t trx, uint8_t ts, uint16_t arfcn,
msgb_free(msg);
}
void pcu_l1if_tx_agch(bitvec * block, int len)
void pcu_l1if_tx_agch(bitvec * block, int plen)
{
uint8_t data[24]; /* prefix PLEN */
uint8_t data[23]; /* prefix PLEN */
/* FIXME: why does OpenBTS has no PLEN and no fill in message? */
bitvec_pack(block, data + 1);
data[0] = (len << 2) | 0x01;
data[0] = (plen << 2) | 0x01;
pcu_tx_data_req(0, 0, PCU_IF_SAPI_AGCH, 0, 0, 0, data, 23);
}