6 files changed, 81 insertions, 2 deletions

diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index bdbad1921..bc3e21e1b 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -27,4 +27,4 @@ osmo_sgsn_SOURCES =	gprs_gmm.c gprs_sgsn.c gprs_sndcp.c gprs_sndcp_vty.c \
 			gsm_04_08_gprs.c
 osmo_sgsn_LDADD = 	\
 			$(top_builddir)/src/libcommon/libcommon.a \
-			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS)
+			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) -lrt
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index 3977c6657..1e1372cd1 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -70,6 +70,7 @@
 #define GSM0408_T3313_SECS	30	/* waiting for paging response */
 #define GSM0408_T3314_SECS	44	/* force to STBY on expiry, Ready timer */
 #define GSM0408_T3316_SECS	44
+#define GSM0408_MOBILE_REACHABLE_SECS (GSM0408_T3312_SECS + 4 * 60)
 
 /* Section 11.3 / Table 11.2d Timers of Session Management - network side */
 #define GSM0408_T3385_SECS	8	/* wait for ACT PDP CTX REQ */
@@ -140,6 +141,11 @@ static void mmctx_timer_stop(struct sgsn_mm_ctx *mm, unsigned int T)
 	osmo_timer_del(&mm->timer);
 }
 
+time_t gprs_max_time_to_idle(void)
+{
+	return GSM0408_T3314_SECS + GSM0408_MOBILE_REACHABLE_SECS;
+}
+
 /* Send a message through the underlying layer */
 static int gsm48_gmm_sendmsg(struct msgb *msg, int command,
 			     struct sgsn_mm_ctx *mm)
diff --git a/openbsc/src/gprs/gprs_llc.c b/openbsc/src/gprs/gprs_llc.c
index 0b4613e0f..9b5bf4b49 100644
--- a/openbsc/src/gprs/gprs_llc.c
+++ b/openbsc/src/gprs/gprs_llc.c
@@ -256,6 +256,7 @@ static struct gprs_llc_llme *llme_alloc(uint32_t tlli)
 	llme->tlli = tlli;
 	llme->old_tlli = 0xffffffff;
 	llme->state = GPRS_LLMS_UNASSIGNED;
+	llme->age_timestamp = GPRS_LLME_RESET_AGE;
 
 	for (i = 0; i < ARRAY_SIZE(llme->lle); i++)
 		lle_init(llme, i);
@@ -622,6 +623,9 @@ int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv)
 		return 0;
 	}
 
+	/* reset age computation */
+	lle->llme->age_timestamp = GPRS_LLME_RESET_AGE;
+
 	/* decrypt information field + FCS, if needed! */
 	if (llhp.is_encrypted) {
 		uint32_t iov_ui = 0; /* FIXME: randomly select for TLLI */
diff --git a/openbsc/src/gprs/gprs_llc_vty.c b/openbsc/src/gprs/gprs_llc_vty.c
index ab5269922..f399b2752 100644
--- a/openbsc/src/gprs/gprs_llc_vty.c
+++ b/openbsc/src/gprs/gprs_llc_vty.c
@@ -23,6 +23,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <stdint.h>
+#include <time.h>
 
 #include <arpa/inet.h>
 
@@ -69,9 +70,13 @@ static uint8_t valid_sapis[] = { 1, 2, 3, 5, 7, 8, 9, 11 };
 static void vty_dump_llme(struct vty *vty, struct gprs_llc_llme *llme)
 {
 	unsigned int i;
+	struct timespec now_tp = {0};
+	clock_gettime(CLOCK_MONOTONIC, &now_tp);
 
-	vty_out(vty, "TLLI %08x (Old TLLI %08x) BVCI=%u NSEI=%u: State %s%s",
+	vty_out(vty, "TLLI %08x (Old TLLI %08x) BVCI=%u NSEI=%u Age=%d: State %s%s",
 		llme->tlli, llme->old_tlli, llme->bvci, llme->nsei,
+		llme->age_timestamp == GPRS_LLME_RESET_AGE ? 0 :
+		(int)(now_tp.tv_sec - (time_t)llme->age_timestamp),
 		get_value_string(gprs_llc_state_strs, llme->state), VTY_NEWLINE);
 
 	for (i = 0; i < ARRAY_SIZE(valid_sapis); i++) {
diff --git a/openbsc/src/gprs/gprs_sgsn.c b/openbsc/src/gprs/gprs_sgsn.c
index 6f706642d..2b78d315c 100644
--- a/openbsc/src/gprs/gprs_sgsn.c
+++ b/openbsc/src/gprs/gprs_sgsn.c
@@ -37,6 +37,10 @@
 #include <openbsc/gprs_gmm.h>
 #include "openbsc/gprs_llc.h"
 
+#include <time.h>
+
+#define GPRS_LLME_CHECK_TICK 30
+
 extern struct sgsn_instance *sgsn;
 
 LLIST_HEAD(sgsn_mm_ctxts);
@@ -508,3 +512,62 @@ void sgsn_update_subscriber_data(struct sgsn_mm_ctx *mmctx,
 
 	sgsn_auth_update(mmctx);
 }
+
+static void sgsn_llme_cleanup_free(struct gprs_llc_llme *llme)
+{
+	struct sgsn_mm_ctx *mmctx = NULL;
+
+	llist_for_each_entry(mmctx, &sgsn_mm_ctxts, list) {
+		if (llme == mmctx->llme) {
+			gsm0408_gprs_access_cancelled(mmctx, SGSN_ERROR_CAUSE_NONE);
+			return;
+		}
+	}
+
+	/* No MM context found */
+	LOGP(DGPRS, LOGL_INFO, "Deleting orphaned LLME, TLLI 0x%08x\n",
+	     llme->tlli);
+	gprs_llgmm_assign(llme, llme->tlli, 0xffffffff, GPRS_ALGO_GEA0, NULL);
+}
+
+static void sgsn_llme_check_cb(void *data_)
+{
+	struct gprs_llc_llme *llme, *llme_tmp;
+	struct timespec now_tp;
+	time_t now, age;
+	time_t max_age = gprs_max_time_to_idle();
+
+	int rc;
+
+	rc = clock_gettime(CLOCK_MONOTONIC, &now_tp);
+	OSMO_ASSERT(rc >= 0);
+	now = now_tp.tv_sec;
+
+	LOGP(DGPRS, LOGL_DEBUG,
+	     "Checking for inactive LLMEs, time = %u\n", (unsigned)now);
+
+	llist_for_each_entry_safe(llme, llme_tmp, &gprs_llc_llmes, list) {
+		if (llme->age_timestamp == GPRS_LLME_RESET_AGE)
+			llme->age_timestamp = now;
+
+		age = now - llme->age_timestamp;
+
+		if (age > max_age || age < 0) {
+			LOGP(DGPRS, LOGL_INFO,
+			     "Inactivity timeout for TLLI 0x%08x, age %d\n",
+			     llme->tlli, (int)age);
+			sgsn_llme_cleanup_free(llme);
+		}
+	}
+
+	osmo_timer_schedule(&sgsn->llme_timer, GPRS_LLME_CHECK_TICK, 0);
+}
+
+void sgsn_inst_init()
+{
+	sgsn->llme_timer.cb = sgsn_llme_check_cb;
+	sgsn->llme_timer.data = NULL;
+
+	osmo_timer_schedule(&sgsn->llme_timer, GPRS_LLME_CHECK_TICK, 0);
+}
+
diff --git a/openbsc/src/gprs/sgsn_main.c b/openbsc/src/gprs/sgsn_main.c
index f26b812a8..0db90d5c3 100644
--- a/openbsc/src/gprs/sgsn_main.c
+++ b/openbsc/src/gprs/sgsn_main.c
@@ -337,6 +337,7 @@ int main(int argc, char **argv)
 	bssgp_nsi = sgsn_inst.cfg.nsi = sgsn_nsi;
 
 	gprs_llc_init("/usr/local/lib/osmocom/crypt/");
+	sgsn_inst_init();
 
 	gprs_ns_vty_init(bssgp_nsi);
 	bssgp_vty_init();