12 May
2023
12 May
'23
9:59 a.m.
dexter has uploaded this change for review. (
https://gerrit.osmocom.org/c/osmo-bsc/+/32693 )
Change subject: pcu_sock: fix PCUIF interface (PCH)
......................................................................
pcu_sock: fix PCUIF interface (PCH)
The PCUIF interface implementation in osmo-bsc provides two ways to
access the paging channel (PCH).
1) Under the SAPI PCU_IF_SAPI_PCH PAGING COMMAND messages are accepted
as whole macblocks but the format is in the style that we are going
to deprecate with PCUIF v.11. Also at the moment those PAGING COMMANDs
are not confirmed towards the PCU, but should (see paging.c in osmo-bts,
which confirms PAGING COMMANDs and IMMEDIATE ASSIGNMENT messages).
2) Under the SAPI PCU_IF_SAPI_PCH_DT messages are also accepded as
macblocks but are also tagged with a TLLI for reference. Those are
confirmed towards the PCU as it should be.
The existence of the two SAPIs in the osmo-bsc implementation are due to
a misconception of the PCUIF and if PAGING COMMAND macblocks should be
confirmed as well. The problem is fixed on osmo-pcu now (see Depends).
Since in osmo-bsc PAGING COMMAND and IMMEDIATE ASSIGNMENT are two
different RSL commands we have to distinguish both by the massage type
field in the macblock now. Also since SAPI SAPI_PCU_IF_PCH is now no
longer used in PCUIF v.11 we may drop this code path.
Depends: osmo-pcu.git I99cfe373fa157cfb32b74c113ad9935347653a71
Related: OS##5927
Change-Id: I82443f2b402aa2416469c8c50b1c050323ef3b8f
---
M include/osmocom/bsc/pcu_if.h
M src/osmo-bsc/abis_rsl.c
M src/osmo-bsc/pcu_sock.c
3 files changed, 56 insertions(+), 49 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/93/32693/1
diff --git a/include/osmocom/bsc/pcu_if.h b/include/osmocom/bsc/pcu_if.h
index 5dc6e37..525b2e4 100644
--- a/include/osmocom/bsc/pcu_if.h
+++ b/include/osmocom/bsc/pcu_if.h
@@ -25,11 +25,7 @@
uint8_t is_11bit, enum ph_burst_type burst_type);
/* Confirm the sending of an immediate assignment to the pcu */
-int pcu_tx_imm_ass_sent(struct gsm_bts *bts, uint32_t tlli);
-
-
-/* Confirm the sending of an immediate assignment to the pcu */
-int pcu_tx_imm_ass_sent(struct gsm_bts *bts, uint32_t tlli);
+int pcu_tx_pch_confirm(struct gsm_bts *bts, uint32_t tlli);
/* Open connection to PCU */
int pcu_sock_init(struct gsm_network *net);
diff --git a/src/osmo-bsc/abis_rsl.c b/src/osmo-bsc/abis_rsl.c
index 72acc85..54357de 100644
--- a/src/osmo-bsc/abis_rsl.c
+++ b/src/osmo-bsc/abis_rsl.c
@@ -2398,7 +2398,7 @@
else {
msgb_pull(msg, 1); /* drop previous data to use msg_pull_u32 */
tlli = msgb_pull_u32(msg);
- pcu_tx_imm_ass_sent(sign_link->trx->bts, tlli);
+ pcu_tx_pch_confirm(sign_link->trx->bts, tlli);
}
return 0;
}
diff --git a/src/osmo-bsc/pcu_sock.c b/src/osmo-bsc/pcu_sock.c
index eb4f265..823b6f6 100644
--- a/src/osmo-bsc/pcu_sock.c
+++ b/src/osmo-bsc/pcu_sock.c
@@ -436,7 +436,7 @@
}
/* Confirm the sending of an immediate assignment to the pcu */
-int pcu_tx_imm_ass_sent(struct gsm_bts *bts, uint32_t tlli)
+int pcu_tx_pch_confirm(struct gsm_bts *bts, uint32_t tlli)
{
struct msgb *msg;
struct gsm_pcu_if *pcu_prim;
@@ -460,9 +460,9 @@
* Encoding::write_paging_request) and extract the mobile identity
* (P-TMSI) from it */
static int pcu_rx_rr_paging(struct gsm_bts *bts, uint8_t paging_group,
- const uint8_t *raw_rr_msg)
+ const struct gsm_pcu_if_pch_dt *pch_dt)
{
- struct gsm48_paging1 *p1 = (struct gsm48_paging1 *) raw_rr_msg;
+ struct gsm48_paging1 *p1 = (struct gsm48_paging1 *) pch_dt->data;
uint8_t chan_needed;
struct osmo_mobile_identity mi;
int rc;
@@ -502,28 +502,25 @@
break;
}
+ pcu_tx_pch_confirm(bts, pch_dt->tlli);
return rc;
}
-/* Helper function for pcu_rx_data_req() to extract paging group info (3 byte) */
-static uint8_t extract_paging_group(struct gsm_bts *bts, uint8_t *data)
+static int pcu_rx_rr_imm_ass(struct gsm_bts *bts, uint8_t paging_group,
+ const struct gsm_pcu_if_pch_dt *pch_dt)
{
- char imsi_digit_buf[4];
- uint8_t pag_grp;
+ LOG_BTS(bts, DPCU, LOGL_DEBUG, "PCU Sends immediate assignment via PCH
(TLLI=0x%08x, IMSI=%s, Paging group=0x%02x)\n",
+ pch_dt->tlli, pch_dt->imsi, paging_group);
- /* the first three bytes are the last three digits of the IMSI, which we need to compute
the paging group */
- imsi_digit_buf[0] = data[0];
- imsi_digit_buf[1] = data[1];
- imsi_digit_buf[2] = data[2];
- imsi_digit_buf[3] = '\0';
+ /* NOTE: Sending an IMMEDIATE ASSIGNMENT via PCH became necessary with GPRS in order to
be able to
+ * assign downlink TBFs directly through the paging channel. However, this method never
became part
+ * of the RSL specs. This means that each BTS vendor has to come up with a proprietary
method. At
+ * the moment we only support Ericsson RBS here. */
+ if (is_ericsson_bts(bts))
+ return rsl_ericsson_imm_assign_cmd(bts, pch_dt->tlli, sizeof(pch_dt->data),
pch_dt->data, paging_group);
- pag_grp = gsm0502_calc_paging_group(&bts->si_common.chan_desc,
- str_to_imsi(imsi_digit_buf));
-
- LOG_BTS(bts, DPCU, LOGL_DEBUG, "Calculating paging group: imsi_digit_buf=%s ==>
pag_grp=0x%02x\n",
- imsi_digit_buf, pag_grp);
-
- return pag_grp;
+ LOG_BTS(bts, DPCU, LOGL_ERROR, "BTS model does not support sending immediate
assignment via PCH!\n");
+ return -ENOTSUP;
}
static int pcu_rx_data_req(struct gsm_bts *bts, uint8_t msg_type,
@@ -532,6 +529,7 @@
uint8_t pag_grp;
int rc = 0;
struct gsm_pcu_if_pch_dt *pch_dt;
+ struct gsm48_imm_ass *gsm48_imm_ass;
LOG_BTS(bts, DPCU, LOGL_DEBUG, "Data request received: sapi=%s arfcn=%d "
"block=%d data=%s\n", sapi_string[data_req->sapi],
@@ -539,18 +537,13 @@
osmo_hexdump(data_req->data, data_req->len));
switch (data_req->sapi) {
- case PCU_IF_SAPI_PCH:
- /* Extract 3 byte paging group */
- pag_grp = extract_paging_group(bts, data_req->data);
- pcu_rx_rr_paging(bts, pag_grp, data_req->data+3);
- break;
case PCU_IF_SAPI_AGCH:
if (rsl_imm_assign_cmd(bts, data_req->len, data_req->data))
rc = -EIO;
break;
case PCU_IF_SAPI_PCH_DT:
/* DT = direct TLLI. A tlli is prefixed so that the BSC/BTS can confirm the sending of
the downlink
- * IMMEDIATE ASSIGNMENT towards the PCU using this TLLI as a reference. */
+ * IMMEDIATE ASSIGNMENT or PAGING COMMAND towards the PCU using this TLLI as a
reference. */
if (data_req->len < sizeof(struct gsm_pcu_if_pch_dt)) {
LOG_BTS(bts, DPCU, LOGL_ERROR, "Received PCU data request with invalid/small
length %d\n",
@@ -561,24 +554,10 @@
pch_dt = (struct gsm_pcu_if_pch_dt *)data_req->data;
pag_grp = gsm0502_calc_paging_group(&bts->si_common.chan_desc,
str_to_imsi(pch_dt->imsi));
- LOG_BTS(bts, DPCU, LOGL_DEBUG, "PCU Sends immediate assignment via PCH
(TLLI=0x%08x, IMSI=%s, Paging group=0x%02x)\n",
- pch_dt->tlli, pch_dt->imsi, pag_grp);
-
- /* NOTE: Sending an IMMEDIATE ASSIGNMENT via PCH became necessary with GPRS in order to
be able to
- * assign downlink TBFs directly through the paging channel. However, this method never
became part
- * of the RSL specs. This means that each BTS vendor has to come up with a proprietary
method. At
- * the moment we only support Ericsson RBS here. */
- if (is_ericsson_bts(bts)) {
- rc = rsl_ericsson_imm_assign_cmd(bts, pch_dt->tlli, sizeof(pch_dt->data),
- pch_dt->data, pag_grp);
- } else {
- LOG_BTS(bts, DPCU, LOGL_ERROR, "BTS model does not support sending immediate
assignment via PCH!\n");
- rc = -ENOTSUP;
- }
-
- if (rc)
- rc = -EIO;
- break;
+ gsm48_imm_ass = (struct gsm48_imm_ass *)pch_dt->data;
+ if (gsm48_imm_ass->msg_type == GSM48_MT_RR_IMM_ASS)
+ return pcu_rx_rr_imm_ass(bts, pag_grp, pch_dt);
+ return pcu_rx_rr_paging(bts, pag_grp, pch_dt);
default:
LOG_BTS(bts, DPCU, LOGL_ERROR, "Received PCU data request with "
"unsupported sapi %d\n", data_req->sapi);
--
To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/32693
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings
Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I82443f2b402aa2416469c8c50b1c050323ef3b8f
Gerrit-Change-Number: 32693
Gerrit-PatchSet: 1
Gerrit-Owner: dexter <pmaier(a)sysmocom.de>
Gerrit-MessageType: newchange