neels has uploaded this change for review. ( 
https://gerrit.osmocom.org/c/osmo-bsc/+/32151 )


Change subject: SCCP N-PCSTATE: trigger MSC status on PC availability
......................................................................

SCCP N-PCSTATE: trigger MSC status on PC availability

Related: SYS#6319
Change-Id: I3a0869598b8395601a16d78dbc46eec400c0ea84
---
M include/osmocom/bsc/bssmap_reset.h
M src/osmo-bsc/bssmap_reset.c
M src/osmo-bsc/osmo_bsc_sigtran.c
3 files changed, 102 insertions(+), 1 deletion(-)



  git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/51/32151/1

diff --git a/include/osmocom/bsc/bssmap_reset.h 
b/include/osmocom/bsc/bssmap_reset.h
index fcd850b..c0de13c 100644
--- a/include/osmocom/bsc/bssmap_reset.h
+++ b/include/osmocom/bsc/bssmap_reset.h
@@ -28,4 +28,5 @@
 struct bssmap_reset *bssmap_reset_alloc(void *ctx, const char *label, const 
struct bssmap_reset_cfg *cfg);
 bool bssmap_reset_is_conn_ready(const struct bssmap_reset *bssmap_reset);
 void bssmap_reset_resend_reset(struct bssmap_reset *bssmap_reset);
+void bssmap_reset_set_disconnected(struct bssmap_reset *bssmap_reset);
 void bssmap_reset_term_and_free(struct bssmap_reset *bssmap_reset);
diff --git a/src/osmo-bsc/bssmap_reset.c b/src/osmo-bsc/bssmap_reset.c
index fa6684d..ac304a5 100644
--- a/src/osmo-bsc/bssmap_reset.c
+++ b/src/osmo-bsc/bssmap_reset.c
@@ -251,6 +251,12 @@
        osmo_fsm_inst_state_chg_ms(bssmap_reset->fi, BSSMAP_RESET_ST_DISC, 1, 
0);
 }

+void bssmap_reset_set_disconnected(struct bssmap_reset *bssmap_reset)
+{
+       /* Go to disconnected state, with the normal RESET timeout to re-send 
RESET. */
+       bssmap_reset_fsm_state_chg(bssmap_reset->fi, BSSMAP_RESET_ST_DISC);
+}
+
 static __attribute__((constructor)) void bssmap_reset_fsm_init(void)
 {
        OSMO_ASSERT(osmo_fsm_register(&bssmap_reset_fsm) == 0);
diff --git a/src/osmo-bsc/osmo_bsc_sigtran.c b/src/osmo-bsc/osmo_bsc_sigtran.c
index 8837330..70dcdc5 100644
--- a/src/osmo-bsc/osmo_bsc_sigtran.c
+++ b/src/osmo-bsc/osmo_bsc_sigtran.c
@@ -36,6 +36,7 @@
 #include <osmocom/bsc/gsm_data.h>
 #include <osmocom/bsc/bts.h>
 #include <osmocom/bsc/paging.h>
+#include <osmocom/bsc/bssmap_reset.h>
 #include <osmocom/mgcp_client/mgcp_common.h>

 /* A pointer to a list with all involved MSCs
@@ -92,7 +93,7 @@
                                  &msc->a.msc_addr, msg);
 }

-/* Find an MSC by its sigtran point code */
+/* Find an MSC by its remote SCCP address */
 static struct bsc_msc_data *get_msc_by_addr(const struct osmo_sccp_addr 
*msc_addr)
 {
        struct osmo_ss7_instance *ss7;
@@ -107,6 +108,19 @@
        return NULL;
 }

+/* Find an MSC by its sigtran point code */
+static struct bsc_msc_data *get_msc_by_pc(uint32_t pc)
+{
+       struct bsc_msc_data *msc;
+       llist_for_each_entry(msc, msc_list, entry) {
+               if ((msc->a.msc_addr.presence & OSMO_SCCP_ADDR_T_PC) == 0)
+                       continue;
+               if (msc->a.msc_addr.pc == pc)
+                       return msc;
+       }
+       return NULL;
+}
+
 /* Received data from MSC, use the connection id which MSC it is */
 static int handle_data_from_msc(struct gsm_subscriber_connection *conn, struct 
msgb *msg)
 {
@@ -188,6 +202,72 @@
        return rc;
 }

+static void handle_pcstate_ind(const struct osmo_scu_pcstate_param *pcst)
+{
+       struct bsc_msc_data *msc;
+       bool connected;
+       bool disconnected;
+
+       LOGP(DMSC, LOGL_DEBUG, "N-PCSTATE ind: affected_pc=%u sp_status=%d 
remote_sccp_status=%d\n",
+            pcst->affected_pc, pcst->sp_status, pcst->remote_sccp_status);
+
+       /* If we don't care about that point-code, ignore PCSTATE. */
+       msc = get_msc_by_pc(pcst->affected_pc);
+       if (!msc)
+               return;
+
+       /* See if this marks the point code to have become available, or to 
have been lost. There are two parts, the
+        * Service Point Status, and the Remote SCCP Status; also this PCSTATE 
may indicate things not related to
+        * connecting or disconnecting. Figure it out with separate flags for 
connect and disconnect: */
+       connected = false;
+       disconnected = false;
+
+       switch (pcst->sp_status) {
+       case OSMO_SCCP_SP_S_ACCESSIBLE:
+               connected = true;
+               break;
+       case OSMO_SCCP_SP_S_INACCESSIBLE:
+               disconnected = true;
+               break;
+       default:
+       case OSMO_SCCP_SP_S_CONGESTED:
+               /* Neither connecting nor disconnecting */
+               break;
+       }
+
+       switch (pcst->remote_sccp_status) {
+       case OSMO_SCCP_REM_SCCP_S_AVAILABLE:
+               if (!disconnected)
+                       connected = true;
+               break;
+       case OSMO_SCCP_REM_SCCP_S_UNAVAILABLE_UNKNOWN:
+       case OSMO_SCCP_REM_SCCP_S_UNEQUIPPED:
+       case OSMO_SCCP_REM_SCCP_S_INACCESSIBLE:
+               disconnected = true;
+               connected = false;
+               break;
+       default:
+       case OSMO_SCCP_REM_SCCP_S_CONGESTED:
+               /* Neither connecting nor disconnecting */
+               break;
+       }
+
+       if (disconnected && a_reset_conn_ready(msc)) {
+               LOGP(DMSC, LOGL_NOTICE,
+                    "(msc%d) now unreachable: N-PCSTATE ind: pc=%u 
sp_status=%d remote_sccp_status=%d\n",
+                    msc->nr, pcst->affected_pc, pcst->sp_status, 
pcst->remote_sccp_status);
+               /* A previously usable MSC has disconnected. Kick the BSSMAP 
back to DISC state. */
+               bssmap_reset_set_disconnected(msc->a.bssmap_reset);
+       } else if (connected && !a_reset_conn_ready(msc)) {
+               LOGP(DMSC, LOGL_NOTICE,
+                    "(msc%d) now available: N-PCSTATE ind: pc=%u sp_status=%d 
remote_sccp_status=%d\n",
+                    msc->nr, pcst->affected_pc, pcst->sp_status, 
pcst->remote_sccp_status);
+               /* A previously unusable MSC has become reachable. Trigger 
immediate BSSMAP RESET -- we would resend a
+                * RESET either way, but we might as well do it now to speed up 
connecting. */
+               bssmap_reset_resend_reset(msc->a.bssmap_reset);
+       }
+}
+
 /* Callback function, called by the SCCP stack when data arrives */
 static int sccp_sap_up(struct osmo_prim_hdr *oph, void *_scu)
 {
@@ -255,6 +335,10 @@
                }
                break;

+       case OSMO_PRIM(OSMO_SCU_PRIM_N_PCSTATE, PRIM_OP_INDICATION):
+               handle_pcstate_ind(&scu_prim->u.pcstate);
+               break;
+
        default:
                LOGP(DMSC, LOGL_ERROR, "Unhandled SIGTRAN operation %s on 
primitive %u\n",
                     get_value_string(osmo_prim_op_names, oph->operation), 
oph->primitive);

--
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I3a0869598b8395601a16d78dbc46eec400c0ea84
Gerrit-Change-Number: 32151
Gerrit-PatchSet: 1
Gerrit-Owner: neels <nhofm...@sysmocom.de>
Gerrit-MessageType: newchange

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