diff options
| author | Vadim Yanitskiy <vyanitskiy@sysmocom.de> | 2020-10-01 21:10:51 +0700 |
|---|---|---|
| committer | laforge <laforge@osmocom.org> | 2020-10-08 07:15:01 +0000 |
| commit | a88fa1f12f81a05558c67802a328114adee69d45 (patch) | |
| tree | 1555942f01968d9d0e3ec28daeab79b25e9d1062 /src/osmo-bsc/gsm_08_08.c | |
| parent | 1ae1826245f7b2148a086e39f9feb8af9679426d (diff) | |
RSL/BSSAP: fix: properly convert between RSL Link ID and DLCI
Data Link Connection Identifier (DLCI) is defined in 3GPP TS 48.006,
section 9.3.2, and coded as follows:
.... .SSS - SAPI value used on the radio link;
CC.. .... - control channel identification:
00.. .... - indicates that the control channel is not further specified,
10.. .... - represents the FACCH or the SDCCH,
11.. .... - represents the SACCH,
other values are reserved.
RSL Link Identifier is defined in 3GPP TS 3GPP TS 48.058,
section 9.3.2, and coded as follows:
.... .SSS - SAPI value used on the radio link;
...P P... - priority for SAPI0 messages;
CC.. .... - control channel identification:
00.. .... - main signalling channel (FACCH or SDCCH),
01.. .... - SACCH,
other values are reserved.
As can be seen, CC bits in both DLCI and RSL Link Identifier
are coded differently. Therefore, we cannot just assign
one identifier to another, we need to do conversion.
I noticed that osmo-bsc indicates DLCI '01000011'B for SMS
messages sent over SACCH/F (SAPI3), and this is wrong because
'01'B is reserved. Let's fix this.
P.S. Interesting coincidence: section 9.3.2 in both documents.
Change-Id: If4d479a54cad467f53b49065c1c435a4471ac7d2
Related: Ica69ae95b47a67ba99ba9cc36629b6bd210d11e4
Related: OS#3716
Diffstat (limited to 'src/osmo-bsc/gsm_08_08.c')
| -rw-r--r-- | src/osmo-bsc/gsm_08_08.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/src/osmo-bsc/gsm_08_08.c b/src/osmo-bsc/gsm_08_08.c index a4b53f09f..f3214c7db 100644 --- a/src/osmo-bsc/gsm_08_08.c +++ b/src/osmo-bsc/gsm_08_08.c @@ -537,6 +537,16 @@ early_exit: return rc; } +/* Data Link Connection Identifier (DLCI) is defined in 3GPP TS 48.006, section 9.3.2. + * .... .SSS - SAPI value used on the radio link; + * CC.. .... - control channel identification: + * 00.. .... - indicates that the control channel is not further specified, + * 10.. .... - represents the FACCH or the SDCCH, + * 11.. .... - represents the SACCH, + * other values are reserved. */ +#define RSL_LINK_ID2DLCI(link_id) \ + (link_id & 0x40 ? 0xc0 : 0x80) | (link_id & 0x07) + /*! MS->BSC/MSC: Um L3 message. */ void bsc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id, struct msgb *msg) { @@ -549,8 +559,9 @@ void bsc_dtap(struct gsm_subscriber_connection *conn, uint8_t link_id, struct ms parse_powercap(conn, msg); - /* Store link_id in msg->cb */ - OBSC_LINKID_CB(msg) = link_id; + /* convert RSL link ID to DLCI, store in msg->cb */ + OBSC_LINKID_CB(msg) = RSL_LINK_ID2DLCI(link_id); + osmo_fsm_inst_dispatch(conn->fi, GSCON_EV_MO_DTAP, msg); done: log_set_context(LOG_CTX_BSC_SUBSCR, NULL); |