pespin has submitted this change. (
https://gerrit.osmocom.org/c/osmo-bsc/+/31797 )
Change subject: bscc_sccp: Avoid allocating conn_id 0x00FFFFFF
......................................................................
bscc_sccp: Avoid allocating conn_id 0x00FFFFFF
The 0x00FFFFFF source local reference is reserved in M3UA/SCCP, hence
avoid allocating a conn_id with that value since later on when reused as
a source local reference it would fail to be encoded.
Change-Id: I5c62bbfa89140d754edccb4404503cb70d5fde89
---
M include/osmocom/bsc/gsm_data.h
M src/osmo-bsc/bsc_sccp.c
2 files changed, 31 insertions(+), 3 deletions(-)
Approvals:
fixeria: Looks good to me, but someone else must approve
daniel: Looks good to me, but someone else must approve
Jenkins Builder: Verified
pespin: Looks good to me, approved
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index 268aa0c..cdf0f43 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -52,7 +52,7 @@
#define GSM_NY1_DEFAULT ((unsigned long)((GSM_T3124_MAX +
GSM_NY1_REQ_DELTA)/GSM_T3105_DEFAULT + 1))
#define SCCP_CONN_ID_UNSET 0xFFFFFFFF
-#define SCCP_CONN_ID_MAX 0x00FFFFFF
+#define SCCP_CONN_ID_MAX 0x00FFFFFE
struct mgcp_client_conf;
struct mgcp_client;
diff --git a/src/osmo-bsc/bsc_sccp.c b/src/osmo-bsc/bsc_sccp.c
index 30d4c4c..431e194 100644
--- a/src/osmo-bsc/bsc_sccp.c
+++ b/src/osmo-bsc/bsc_sccp.c
@@ -21,6 +21,8 @@
*
*/
+#include <osmocom/core/utils.h>
+
#include <osmocom/bsc/gsm_data.h>
#include <osmocom/bsc/bsc_msc_data.h>
#include <osmocom/bsc/lb.h>
@@ -31,6 +33,17 @@
static uint32_t next_id = 1;
int i;
+ /* SUA: RFC3868 sec 3.10.4:
+ * The source reference number is a 4 octet long integer.
+ * This is allocated by the source SUA instance.
+ * M3UA/SCCP: ITU-T Q.713 sec 3.3:
+ * The "source local reference" parameter field is a three-octet
field containing a
+ * reference number which is generated and used by the local node to
identify the
+ * connection section after the connection section is set up.
+ * The coding "all ones" is reserved for future use.
+ * Hence, let's simply use 24 bit ids to fit all link types (excluding
0x00ffffff).
+ */
+
/* This looks really suboptimal, but in most cases the static next_id
should indicate exactly the next unused
* conn_id, and we only iterate all conns once to make super sure that
it is not already in use. */
@@ -39,8 +52,10 @@
uint32_t conn_id = next_id;
bool conn_id_already_used = false;
- /* Optimized modulo operation using bitwise AND: */
- next_id = (next_id + 1) & SCCP_CONN_ID_MAX;
+ /* Optimized modulo operation (% SCCP_CONN_ID_MAX) using
bitwise AND plus CMP: */
+ next_id = (next_id + 1) & 0x00FFFFFF;
+ if (OSMO_UNLIKELY(next_id == 0x00FFFFFF))
+ next_id = 0;
llist_for_each_entry(conn, &bsc_gsmnet->subscr_conns, entry) {
if (conn->sccp.msc && conn->sccp.msc->a.sccp == sccp) {
--
To view, visit https://gerrit.osmocom.org/c/osmo-bsc/+/31797
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings
Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I5c62bbfa89140d754edccb4404503cb70d5fde89
Gerrit-Change-Number: 31797
Gerrit-PatchSet: 4
Gerrit-Owner: pespin <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: daniel <[email protected]>
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-MessageType: merged
