move next_teid from up_endpoint to g_upf

up_endpoint is about the PFCP endpoint, handing out local TEID is about
local GTP endpoints. Move the TEID allocation to g_upf / upf.c.

An upcoming patch will use a hash table in g_upf to speed up lookup
whether a local TEID is already in use; cosmetically prepare for that.

Change-Id: I8eae5b53c563400ddfded264678d9cfb28b6f737

include/osmocom/upf/up_endpoint.h

@@ -39,11 +39,9 @@ struct up_endpoint {
 	struct llist_head peers;
 
 	uint64_t next_seid_state;
-	uint32_t next_teid_state;
 };
 
 struct up_endpoint *up_endpoint_init(void *ctx, const struct osmo_sockaddr *local_addr);
 void up_endpoint_free(struct up_endpoint **ep);
 
 uint64_t up_endpoint_next_seid(struct up_endpoint *ep);
-uint32_t up_endpoint_next_teid(struct up_endpoint *ep);

include/osmocom/upf/upf.h

@@ -115,6 +115,10 @@ struct g_upf {
 		uint32_t next_chain_id_state;
 	} tunmap;
 
+	struct {
+		uint32_t next_local_teid_state;
+	} gtp;
+
 	struct llist_head netinst;
 };
 
@@ -134,3 +138,5 @@ int upf_pfcp_listen();
 
 int upf_gtp_devs_open();
 void upf_gtp_devs_close();
+
+uint32_t upf_next_local_teid(void);

src/osmo-upf/up_endpoint.c

@@ -271,17 +271,6 @@ static struct up_session *up_endpoint_find_session(struct up_endpoint *ep, uint6
 		return NULL;
 }
 
-static struct up_session *up_endpoint_find_session_by_local_teid(struct up_endpoint *ep, uint32_t teid)
-{
-		struct up_peer *peer;
-		llist_for_each_entry(peer, &ep->peers, entry) {
-			struct up_session *session = up_session_find_by_local_teid(peer, teid);
-			if (session)
-				return session;
-		}
-		return NULL;
-}
-
 uint64_t up_endpoint_next_seid(struct up_endpoint *ep)
 {
 	uint64_t sanity;
@@ -294,26 +283,6 @@ uint64_t up_endpoint_next_seid(struct up_endpoint *ep)
 	return 0;
 }
 
-static uint32_t up_endpoint_inc_teid(struct up_endpoint *ep)
-{
-	ep->next_teid_state++;
-	if (!ep->next_teid_state)
-		ep->next_teid_state++;
-	return ep->next_teid_state;
-}
-
-uint32_t up_endpoint_next_teid(struct up_endpoint *ep)
-{
-	uint32_t sanity;
-	for (sanity = 2342; sanity; sanity--) {
-		uint32_t next_teid = up_endpoint_inc_teid(ep);
-		if (up_endpoint_find_session_by_local_teid(ep, next_teid))
-			continue;
-		return next_teid;
-	}
-	return 0;
-}
-
 void up_endpoint_free(struct up_endpoint **_ep)
 {
 	struct up_peer *peer;

src/osmo-upf/up_session.c

@@ -185,7 +185,6 @@ static enum osmo_pfcp_cause up_session_choose_f_teid(struct up_session *session,
 						     bool choose_id_present, uint8_t choose_id,
 						     const char *netinst_name)
 {
-	struct up_endpoint *up_ep = session->up_peer->up_endpoint;
 	struct chosen_f_teid *chosen = NULL;
 
 	if (choose_id_present)
@@ -206,7 +205,7 @@ static enum osmo_pfcp_cause up_session_choose_f_teid(struct up_session *session,
 			return rc;
 
 		/* Choose a new TEID */
-		dst->fixed.teid = up_endpoint_next_teid(up_ep);
+		dst->fixed.teid = upf_next_local_teid();
 		if (dst->fixed.teid == 0) {
 			LOGPFSML(session->fi, LOGL_ERROR, "Failed to allocate an unused TEID\n");
 			return OSMO_PFCP_CAUSE_PFCP_ENTITY_IN_CONGESTION;

src/osmo-upf/upf.c

@@ -29,6 +29,8 @@
 
 #include <osmocom/upf/upf.h>
 #include <osmocom/upf/up_endpoint.h>
+#include <osmocom/upf/up_peer.h>
+#include <osmocom/upf/up_session.h>
 #include <osmocom/upf/upf_gtp.h>
 
 struct g_upf *g_upf = NULL;
@@ -98,3 +100,34 @@ int upf_gtp_devs_open()
 	}
 	return 0;
 }
+
+static bool upf_is_local_teid_in_use(uint32_t teid)
+{
+	struct up_peer *peer;
+	llist_for_each_entry(peer, &g_upf->pfcp.ep->peers, entry) {
+		struct up_session *session = up_session_find_by_local_teid(peer, teid);
+		if (session)
+			return true;
+	}
+	return false;
+}
+
+static uint32_t upf_next_local_teid_inc(void)
+{
+	g_upf->gtp.next_local_teid_state++;
+	if (!g_upf->gtp.next_local_teid_state)
+		g_upf->gtp.next_local_teid_state++;
+	return g_upf->gtp.next_local_teid_state;
+}
+
+uint32_t upf_next_local_teid(void)
+{
+	uint32_t sanity;
+	for (sanity = 2342; sanity; sanity--) {
+		uint32_t next_teid = upf_next_local_teid_inc();
+		if (upf_is_local_teid_in_use(next_teid))
+			continue;
+		return next_teid;
+	}
+	return 0;
+}