fixeria has uploaded this change for review. (
https://gerrit.osmocom.org/c/osmo-bts/+/38316?usp=email )
Change subject: l1sap: ensure DL RLP frame alignment for TCH/F4.8 NT
......................................................................
l1sap: ensure DL RLP frame alignment for TCH/F4.8 NT
Related: OS#6578
Change-Id: Ic8ec1a5d84950d27b22fd7491d5e4a82ace9fd62
---
M include/osmo-bts/csd_v110.h
M src/common/csd_v110.c
M src/common/l1sap.c
M tests/csd/csd_test.c
4 files changed, 31 insertions(+), 7 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/16/38316/1
diff --git a/include/osmo-bts/csd_v110.h b/include/osmo-bts/csd_v110.h
index f1c1027..54a6745 100644
--- a/include/osmo-bts/csd_v110.h
+++ b/include/osmo-bts/csd_v110.h
@@ -22,4 +22,4 @@
int csd_v110_rtp_encode(const struct gsm_lchan *lchan, uint8_t *rtp,
const uint8_t *data, size_t data_len, uint32_t fn);
int csd_v110_rtp_decode(const struct gsm_lchan *lchan, uint8_t *data,
- const uint8_t *rtp, size_t rtp_len);
+ const uint8_t *rtp, size_t rtp_len, uint32_t fn);
diff --git a/src/common/csd_v110.c b/src/common/csd_v110.c
index d25eb7b..f214735 100644
--- a/src/common/csd_v110.c
+++ b/src/common/csd_v110.c
@@ -158,7 +158,7 @@
}
int csd_v110_rtp_decode(const struct gsm_lchan *lchan, uint8_t *data,
- const uint8_t *rtp, size_t rtp_len)
+ const uint8_t *rtp, size_t rtp_len, uint32_t fn)
{
const struct csd_v110_frame_desc *desc;
ubit_t ra_bits[80 * 4];
@@ -187,6 +187,23 @@
ra_bits[i] = (rtp[i] >> 7);
}
+ /* TCH/F4.8 NT: check RLP frame alignment */
+ if (lchan->tch_mode == GSM48_CMODE_DATA_6k0 &&
+ lchan->csd_mode == LCHAN_CSD_M_NT) {
+ const ubit_t e2 = csd_v110_tchf48_nt_e2_map[fn % 26];
+ const ubit_t *e_bits;
+
+ /* check bits E2/E3 in the 1st V.110 frame */
+ e_bits = &ra_bits[0 * 80 + 5 * 8 + 1];
+ if (e_bits[1] != e2 || e_bits[2] != 0)
+ return -EAGAIN;
+ /* check bits E2/E3 in the 2nd V.110 frame */
+ e_bits = &ra_bits[1 * 80 + 5 * 8 + 1];
+ if (e_bits[1] != e2 || e_bits[2] != 1)
+ return -EAGAIN;
+ /* -EAGAIN means postpone transmission */
+ }
+
/* RA1'/RA1: convert from an intermediate rate to radio rate */
for (unsigned int i = 0; i < desc->num_blocks; i++) {
struct osmo_v110_decoded_frame df;
diff --git a/src/common/l1sap.c b/src/common/l1sap.c
index 85e986d..3f7aa6a 100644
--- a/src/common/l1sap.c
+++ b/src/common/l1sap.c
@@ -1635,11 +1635,11 @@
memcpy(&rtp[0], msgb_l2(resp_msg),
OSMO_MIN(msgb_l2len(resp_msg), sizeof(rtp)));
- msgb_get(resp_msg, msgb_l2len(resp_msg));
int rc = csd_v110_rtp_decode(lchan, msgb_l2(resp_msg),
- &rtp[0], sizeof(rtp));
+ &rtp[0], sizeof(rtp), fn);
if (rc > 0) {
+ msgb_get(resp_msg, msgb_l2len(resp_msg));
msgb_put(resp_msg, rc);
/* 'fake' tch_ind containing all-zero so gsmtap
code can be shared
* between UL and DL */
@@ -1648,8 +1648,15 @@
msgb_l2(resp_msg),
msgb_l2len(resp_msg));
} else {
- rate_ctr_inc2(trx->bts->ctrs,
BTS_CTR_RTP_RX_DROP_V110_DEC);
- msgb_free(resp_msg);
+ if (rc == -EAGAIN) {
+ /* enqueue back, postpone transmission
+ * XXX: we don't have
msgb_enqueue_tail[_count]() */
+ llist_add(&resp_msg->list,
&lchan->dl_tch_queue);
+ lchan->dl_tch_queue_len++;
+ } else {
+ rate_ctr_inc2(trx->bts->ctrs,
BTS_CTR_RTP_RX_DROP_V110_DEC);
+ msgb_free(resp_msg);
+ }
resp_msg = NULL;
resp_l1sap = &empty_l1sap;
}
diff --git a/tests/csd/csd_test.c b/tests/csd/csd_test.c
index bef0ec8..0ca7209 100644
--- a/tests/csd/csd_test.c
+++ b/tests/csd/csd_test.c
@@ -136,7 +136,7 @@
fprintf(stderr, " %s\n", osmo_hexdump(&rtp[i * 16], 16));
/* decode the encoded RTP frame */
- rc = csd_v110_rtp_decode(&lchan, &data_dec[0], &rtp[0], sizeof(rtp));
+ rc = csd_v110_rtp_decode(&lchan, &data_dec[0], &rtp[0], sizeof(rtp), 0);
fprintf(stderr, "[i] csd_v110_rtp_decode() returns %d\n", rc);
if (rc != bit_num)
return;
--
To view, visit https://gerrit.osmocom.org/c/osmo-bts/+/38316?usp=email
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings?usp=email
Gerrit-MessageType: newchange
Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-Change-Id: Ic8ec1a5d84950d27b22fd7491d5e4a82ace9fd62
Gerrit-Change-Number: 38316
Gerrit-PatchSet: 1
Gerrit-Owner: fixeria <[email protected]>
