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authorJonathan Santos <jrsantos@jonathanrsantos.com>2011-06-22 12:13:59 -0400
committerJonathan Santos <jrsantos@jonathanrsantos.com>2011-07-21 15:30:41 -0400
commite5b7ad8119837f68b3bc1e53beb8f03deff21938 (patch)
tree2d4944d9747d5ad82fe6a2d386d2dc0e0bd4b94e
parent5f7d3cd6d2c2790c186a6d83286b6f9ee68e5f71 (diff)
gprs: Reset LLC state when Timer 3350 expires
This works around a problem that occurs if a mobile loses packet data connectivity, e.g. moves out of coverage or switches over to a circuit-switched call, while a data transfer is occurring. The mobile would reset its LLC state, causing it to be unsynchronized with the SGSN. Therefore the SGSN would drop incoming frames until the sequence numbers matched. This workaround resets the LLC state in the SGSN if T3350 expires, indicating that Routing Area Updating Request, Attach Request, or P-TMSI Realloc Command has failed.
-rw-r--r--include/openbsc/gprs_llc.h1
-rw-r--r--src/gprs/gprs_gmm.c1
-rw-r--r--src/gprs/gprs_llc.c24
3 files changed, 26 insertions, 0 deletions
diff --git a/include/openbsc/gprs_llc.h b/include/openbsc/gprs_llc.h
index 5949ac3b..aa3b9ccb 100644
--- a/include/openbsc/gprs_llc.h
+++ b/include/openbsc/gprs_llc.h
@@ -160,6 +160,7 @@ int gprs_llgmm_assign(struct gprs_llc_llme *llme,
int gprs_llgmm_suspend(struct gprs_llc_llme *llme);
int gprs_llgmm_resume(struct gprs_llc_llme *llme);
+void gprs_llgmm_reset_state(struct gprs_llc_llme *llme);
int gprs_llc_init(const char *cipher_plugin_path);
int gprs_llc_vty_init(void);
diff --git a/src/gprs/gprs_gmm.c b/src/gprs/gprs_gmm.c
index d6cd4125..f98dcf0d 100644
--- a/src/gprs/gprs_gmm.c
+++ b/src/gprs/gprs_gmm.c
@@ -1075,6 +1075,7 @@ static void mmctx_timer_cb(void *_mm)
if (mm->num_T_exp >= 5) {
LOGP(DMM, LOGL_NOTICE, "T3350 expired >= 5 times\n");
gprs_llgmm_resume(mm->llme);
+ gprs_llgmm_reset_state(mm->llme);
break;
}
/* re-transmit the respective msg and re-start timer */
diff --git a/src/gprs/gprs_llc.c b/src/gprs/gprs_llc.c
index 07294aad..c5ff7294 100644
--- a/src/gprs/gprs_llc.c
+++ b/src/gprs/gprs_llc.c
@@ -868,6 +868,30 @@ int gprs_llgmm_resume(struct gprs_llc_llme* llme)
return 0;
}
+void gprs_llgmm_reset_state(struct gprs_llc_llme *llme)
+{
+ unsigned int i;
+
+ if (llme == 0)
+ {
+ LOGP(DLLC, LOGL_ERROR, "LLC TX: trying to reset LLC states "
+ "but passed null llme by gmm\n");
+ return;
+ }
+
+ LOGP(DLLC, LOGL_NOTICE, "LLC RX: reset state variable for TLLI 0x%08x",
+ llme->tlli);
+ /* 8.5.3.1 For all LLE's */
+ for (i = 0; i < ARRAY_SIZE(llme->lle); i++) {
+ struct gprs_llc_lle *l = &llme->lle[i];
+ l->vu_recv = 0; /* lets not mess with send state variable now */
+ /* l->vu_send = l->vu_recv = 0; */
+ l->retrans_ctr = 0;
+ l->state = GPRS_LLES_ASSIGNED_ADM;
+ /* FIXME Set parameters according to table 9 */
+ }
+}
+
int gprs_llc_init(const char *cipher_plugin_path)
{
return gprs_cipher_load(cipher_plugin_path);