From 21b269f81454919a379d22b9c2be74bb680be500 Mon Sep 17 00:00:00 2001
From: Daniel Willmann <dwillmann@sysmocom.de>
Date: Wed, 11 May 2016 12:43:47 +0200
Subject: [PATCH] IuPS: Change GTP-U endpoint to SGSN in PMM_IDLE and page UE
 when data arrives

Change-Id: I47b73a40cbdda6b7c31fb2767f74f9f93d84056b
---
 openbsc/include/openbsc/sgsn.h |  1 +
 openbsc/src/gprs/gprs_gmm.c    | 13 ++++++++++++-
 openbsc/src/gprs/sgsn_libgtp.c | 19 +++++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/openbsc/include/openbsc/sgsn.h b/openbsc/include/openbsc/sgsn.h
index 19496cbf8..22809b794 100644
--- a/openbsc/include/openbsc/sgsn.h
+++ b/openbsc/include/openbsc/sgsn.h
@@ -138,6 +138,7 @@ struct sgsn_pdp_ctx *sgsn_create_pdp_ctx(struct sgsn_ggsn_ctx *ggsn,
 					 uint16_t nsapi,
 					 struct tlv_parsed *tp);
 int sgsn_delete_pdp_ctx(struct sgsn_pdp_ctx *pctx);
+void sgsn_pdp_upd_gtp_u(struct sgsn_pdp_ctx *pdp, void *addr, size_t alen);
 
 /* gprs_sndcp.c */
 
diff --git a/openbsc/src/gprs/gprs_gmm.c b/openbsc/src/gprs/gprs_gmm.c
index cb3d4eeb7..3d7464755 100644
--- a/openbsc/src/gprs/gprs_gmm.c
+++ b/openbsc/src/gprs/gprs_gmm.c
@@ -109,6 +109,16 @@ static const struct tlv_definition gsm48_sm_att_tlvdef = {
 
 static int gsm48_gmm_authorize(struct sgsn_mm_ctx *ctx);
 
+static void mmctx_change_gtpu_endpoints_to_sgsn(struct sgsn_mm_ctx *mm_ctx)
+{
+	struct sgsn_pdp_ctx *pdp;
+	llist_for_each_entry(pdp, &mm_ctx->pdp_list, list) {
+		sgsn_pdp_upd_gtp_u(pdp,
+				   &sgsn->cfg.gtp_listenaddr.sin_addr,
+				   sizeof(sgsn->cfg.gtp_listenaddr.sin_addr));
+	}
+}
+
 void mmctx_set_pmm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
 {
 	if (ctx->pmm_state == state)
@@ -120,7 +130,8 @@ void mmctx_set_pmm_state(struct sgsn_mm_ctx *ctx, enum gprs_pmm_state state)
 	{
 		switch (state) {
 		case PMM_IDLE:
-			/* TODO: Change GTP-U endpoints to SGSN, start RA Upd timer */
+			/* TODO: start RA Upd timer */
+			mmctx_change_gtpu_endpoints_to_sgsn(ctx);
 			break;
 		case PMM_CONNECTED:
 			break;
diff --git a/openbsc/src/gprs/sgsn_libgtp.c b/openbsc/src/gprs/sgsn_libgtp.c
index 35d5dab3d..04bd40aeb 100644
--- a/openbsc/src/gprs/sgsn_libgtp.c
+++ b/openbsc/src/gprs/sgsn_libgtp.c
@@ -401,6 +401,13 @@ reject:
 	return EOF;
 }
 
+void sgsn_pdp_upd_gtp_u(struct sgsn_pdp_ctx *pdp, void *addr, size_t alen)
+{
+	pdp->lib->gsnlu.l = alen;
+	memcpy(pdp->lib->gsnlu.v, addr, alen);
+	gtp_update_context(pdp->ggsn->gsn, pdp->lib, pdp, &pdp->lib->hisaddr0);
+}
+
 #ifdef BUILD_IU
 /* Callback for RAB assignment response */
 int sgsn_ranap_rab_ass_resp(struct sgsn_mm_ctx *ctx, RANAP_RAB_SetupOrModifiedItemIEs_t *setup_ies)
@@ -621,6 +628,18 @@ static int cb_data_ind(struct pdp_t *lib, void *packet, unsigned int len)
 		return -EIO;
 	}
 
+	if (mm->ran_type == MM_CTX_T_UTRAN_Iu) {
+#ifdef BUILD_IU
+		/* Ignore the packet for now and page the UE to get the RAB
+		 * reestablished */
+		iu_page_ps(mm->imsi, &mm->p_tmsi, mm->ra.lac, mm->ra.rac);
+
+		return 0;
+#else
+		return -ENOTSUP;
+#endif
+	}
+
 	msg = msgb_alloc_headroom(len+256, 128, "GTP->SNDCP");
 	ud = msgb_put(msg, len);
 	memcpy(ud, packet, len);