From 7ad066c5c380a93aa525356ff588c1f8776ad4a2 Mon Sep 17 00:00:00 2001
From: Jonathan Santos <jrsantos@jonathanrsantos.com>
Date: Fri, 10 Jun 2011 17:25:48 -0400
Subject: gprs: Suspend user data transmission during Routing Area Updating

TS 24.008 version 9.5.0 Release 9 sec 4.7.5:
     In A/Gb mode, user data transmission in the MS shall be
     suspended during the routing area updating procedure, except
     if the routing area updating procedure is triggered by a PS
     handover procedure as described in 3GPP TS 43.129 [113];
     user data reception shall be possible. User data transmission
     in the network may be suspended during the routing area
     updating procedure.
---
 include/openbsc/gprs_llc.h |  4 ++++
 src/gprs/gprs_gmm.c        |  5 +++++
 src/gprs/gprs_llc.c        | 18 ++++++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/include/openbsc/gprs_llc.h b/include/openbsc/gprs_llc.h
index 02945e164..5949ac3b8 100644
--- a/include/openbsc/gprs_llc.h
+++ b/include/openbsc/gprs_llc.h
@@ -140,6 +140,8 @@ struct gprs_llc_llme {
 	uint16_t bvci;
 	uint16_t nsei;
 	struct gprs_llc_lle lle[NUM_SAPIS];
+
+	int suspended;
 };
 
 extern struct llist_head gprs_llc_llmes;
@@ -156,6 +158,8 @@ int gprs_llgmm_assign(struct gprs_llc_llme *llme,
 		      uint32_t old_tlli, uint32_t new_tlli,
 		      enum gprs_ciph_algo alg, const uint8_t *kc);
 
+int gprs_llgmm_suspend(struct gprs_llc_llme *llme);
+int gprs_llgmm_resume(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 b722f1212..d6cd4125c 100644
--- a/src/gprs/gprs_gmm.c
+++ b/src/gprs/gprs_gmm.c
@@ -937,6 +937,8 @@ static int gsm48_rx_gmm_ra_upd_req(struct sgsn_mm_ctx *mmctx, struct msgb *msg,
 		return gsm48_tx_gmm_ra_upd_rej(msg, GMM_CAUSE_MS_ID_NOT_DERIVED);
 	}
 
+	gprs_llgmm_suspend(mmctx->llme);
+
 	/* Store new BVCI/NSEI in MM context (FIXME: delay until we ack?) */
 	msgid2mmctx(mmctx, msg);
 	/* Bump the statistics of received signalling msgs for this MM context */
@@ -1027,6 +1029,7 @@ static int gsm0408_rcv_gmm(struct sgsn_mm_ctx *mmctx, struct msgb *msg,
 		gprs_llgmm_assign(mmctx->llme, mmctx->tlli, mmctx->tlli_new,
 				GPRS_ALGO_GEA0, NULL);
 		mmctx->tlli = mmctx->tlli_new;
+		gprs_llgmm_resume(mmctx->llme);
 		break;
 	case GSM48_MT_GMM_RA_UPD_COMPL:
 		/* only in case SGSN offered new P-TMSI */
@@ -1037,6 +1040,7 @@ static int gsm0408_rcv_gmm(struct sgsn_mm_ctx *mmctx, struct msgb *msg,
 		gprs_llgmm_assign(mmctx->llme, mmctx->tlli, mmctx->tlli_new,
 				GPRS_ALGO_GEA0, NULL);
 		mmctx->tlli = mmctx->tlli_new;
+		gprs_llgmm_resume(mmctx->llme);
 		break;
 	case GSM48_MT_GMM_PTMSI_REALL_COMPL:
 		DEBUGP(DMM, "-> PTMSI REALLLICATION COMPLETE\n");
@@ -1070,6 +1074,7 @@ static void mmctx_timer_cb(void *_mm)
 	case 3350:	/* waiting for ATTACH COMPLETE */
 		if (mm->num_T_exp >= 5) {
 			LOGP(DMM, LOGL_NOTICE, "T3350 expired >= 5 times\n");
+			gprs_llgmm_resume(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 37bd8804f..0b4a5de94 100644
--- a/src/gprs/gprs_llc.c
+++ b/src/gprs/gprs_llc.c
@@ -350,6 +350,12 @@ int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command,
 		return -EFBIG;
 	}
 
+	if ((sapi != GPRS_SAPI_GMM) && lle->llme->suspended) {
+		LOGP(DLLC, LOGL_DEBUG, "LLC TX: suspended TLLI 0x08x, "
+			"dropping UI frame\n", msgb_tlli(msg));
+		return 0;
+	}
+
 	/* Update LLE's (BVCI, NSEI) tuple */
 	lle->llme->bvci = msgb_bvci(msg);
 	lle->llme->nsei = msgb_nsei(msg);
@@ -846,6 +852,18 @@ int gprs_llgmm_assign(struct gprs_llc_llme *llme,
 	return 0;
 }
 
+int gprs_llgmm_suspend(struct gprs_llc_llme* llme)
+{
+	llme->suspended = 1;
+	return 0;
+}
+
+int gprs_llgmm_resume(struct gprs_llc_llme* llme)
+{
+	llme->suspended = 0;
+	return 0;
+}
+
 int gprs_llc_init(const char *cipher_plugin_path)
 {
 	return gprs_cipher_load(cipher_plugin_path);
-- 
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