HO: Implement load based handover, as handover_decision_2.c

Change-Id: Ice2d3ef5668564a9d3bc4d5118d59dfaa9af6978

7 files changed, 46 insertions, 4 deletions

diff --git a/include/osmocom/bsc/Makefile.am b/include/osmocom/bsc/Makefile.am
index 699aeb339..a3d9adfd8 100644
--- a/include/osmocom/bsc/Makefile.am
+++ b/include/osmocom/bsc/Makefile.am
@@ -27,6 +27,7 @@ noinst_HEADERS = \
 	handover.h \
 	handover_cfg.h \
 	handover_decision.h \
+	handover_decision_2.h \
 	handover_vty.h \
 	ipaccess.h \
 	meas_feed.h \
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index cd4997c8a..28314835c 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -10,6 +10,7 @@
 #include <osmocom/core/rate_ctr.h>
 #include <osmocom/core/select.h>
 #include <osmocom/core/stats.h>
+#include <osmocom/gsm/protocol/gsm_08_08.h>
 
 #include <osmocom/crypt/auth.h>
 #include <osmocom/sigtran/sccp_sap.h>
@@ -72,8 +73,8 @@ struct gsm_classmark {
 /* penalty timers for handover */
 struct ho_penalty_timer {
 	struct llist_head entry;
-	uint8_t bts;
-	time_t timeout;
+	uint8_t bts_nr;
+	unsigned int timeout;
 };
 
 /* active radio connection of a mobile subscriber */
@@ -108,10 +109,20 @@ struct gsm_subscriber_connection {
 
 	/* penalty timers for handover */
 	struct llist_head ho_penalty_timers;
+	int ho_failure;
 
 	/* Cache DTAP messages during handover/assignment (msgb_enqueue()/msgb_dequeue())*/
 	struct llist_head ho_dtap_cache;
 	unsigned int ho_dtap_cache_len;
+
+	/* "Codec List (MSC Preferred)" as received by the BSSAP Assignment Request. 3GPP 48.008
+	 * 3.2.2.103 says:
+	 *         The "Codec List (MSC Preferred)" shall not include codecs
+	 *         that are not supported by the MS.
+	 * i.e. by heeding the "Codec list (MSC Preferred)", we inherently heed the MS bearer
+	 * capabilities, which the MSC is required to translate into the codec list. */
+	struct gsm0808_speech_codec_list codec_list;
+	bool codec_list_present;
 };
 
 static inline struct gsm_bts *conn_get_bts(struct gsm_subscriber_connection *conn) {
@@ -441,4 +452,11 @@ void gsm_bts_set_radio_link_timeout(struct gsm_bts *bts, int value);
 
 bool classmark_is_r99(struct gsm_classmark *cm);
 
+void conn_penalty_timer_add(struct gsm_subscriber_connection *conn,
+			    struct gsm_bts *bts, int timeout);
+unsigned int conn_penalty_timer_remaining(struct gsm_subscriber_connection *conn,
+					  struct gsm_bts *bts);
+void conn_penalty_timer_clear(struct gsm_subscriber_connection *conn,
+			      struct gsm_bts *bts);
+
 #endif /* _GSM_DATA_H */
diff --git a/include/osmocom/bsc/gsm_data_shared.h b/include/osmocom/bsc/gsm_data_shared.h
index 277366dd9..0f325ecba 100644
--- a/include/osmocom/bsc/gsm_data_shared.h
+++ b/include/osmocom/bsc/gsm_data_shared.h
@@ -801,7 +801,11 @@ struct gsm_bts {
 
 	struct rate_ctr_group *bts_ctrs;
 
-	struct handover_cfg *ho;
+	struct {
+		struct handover_cfg *cfg;
+		struct osmo_timer_list congestion_check_timer;
+		/* todo: move them here */ //struct llist_head penalty_timeouts;
+	} ho;
 };
 
 
diff --git a/include/osmocom/bsc/handover.h b/include/osmocom/bsc/handover.h
index a9349eeda..f76445695 100644
--- a/include/osmocom/bsc/handover.h
+++ b/include/osmocom/bsc/handover.h
@@ -5,6 +5,8 @@ struct gsm_bts;
 struct gsm_subscriber_connection;
 
 int bsc_handover_start(struct gsm_lchan *old_lchan, struct gsm_bts *bts);
+int bsc_handover_start_lchan_change(struct gsm_lchan *old_lchan, struct gsm_bts *bts,
+				    enum gsm_chan_t new_lchan_type);
 void bsc_clear_handover(struct gsm_subscriber_connection *conn, int free_lchan);
 struct gsm_lchan *bsc_handover_pending(struct gsm_lchan *new_lchan);
 
diff --git a/include/osmocom/bsc/handover_cfg.h b/include/osmocom/bsc/handover_cfg.h
index b5a0d1b7d..ff73fa328 100644
--- a/include/osmocom/bsc/handover_cfg.h
+++ b/include/osmocom/bsc/handover_cfg.h
@@ -20,6 +20,13 @@ struct handover_cfg *ho_cfg_init(void *ctx, enum handover_cfg_ctx_type ctx_type,
 
 typedef void (*ho_cfg_on_change_cb_t)(void *ctx, enum handover_cfg_ctx_type ctx_type);
 
+/* ho_cfg_* code gets called during initialization of the global gsm_network struct, which is included in
+ * various utility programs that don't need most of gsm_data.c, definitely no handover. The on_change
+ * callback from the ho_cfg touches internals of the handover decision, which would cause utility
+ * programs to require linking of most of the handover code. To break this linking cascade, have the
+ * on_change callbacks as function pointers. */
+extern ho_cfg_on_change_cb_t ho_cfg_on_change_congestion_check_interval_cb;
+
 #define HO_CFG_STR_HANDOVER "Handover options\n"
 #define HO_CFG_STR_WIN HO_CFG_STR_HANDOVER "Measurement averaging settings\n"
 #define HO_CFG_STR_WIN_RXLEV HO_CFG_STR_WIN "Received-Level averaging\n"
@@ -157,7 +164,8 @@ static inline const char *congestion_check_interval2a(int val)
 		"Disable in-call assignment\n" \
 		"Enable in-call assignment\n") \
 	\
-	HO_CFG_ONE_MEMBER(int, congestion_check_interval, 10, NULL, \
+	HO_CFG_ONE_MEMBER(int, congestion_check_interval, 10, \
+		ho_cfg_on_change_congestion_check_interval_cb, \
 		"handover congestion-check", "disabled|<1-60>", \
 		a2congestion_check_interval, "%s", congestion_check_interval2a, \
 		HO_CFG_STR_HANDOVER \
diff --git a/include/osmocom/bsc/handover_decision_2.h b/include/osmocom/bsc/handover_decision_2.h
new file mode 100644
index 000000000..94e9c8663
--- /dev/null
+++ b/include/osmocom/bsc/handover_decision_2.h
@@ -0,0 +1,8 @@
+/* Handover Decision Algorithm 2 for intra-BSC (inter-BTS) handover, public API for OsmoBSC */
+
+#pragma once
+struct gsm_bts;
+
+void handover_decision_2_init(struct gsm_network *net);
+
+void handover_decision_2_bts_congestion_check(struct gsm_bts *bts);
diff --git a/include/osmocom/bsc/signal.h b/include/osmocom/bsc/signal.h
index 9c0d5a3de..1c8b51e3c 100644
--- a/include/osmocom/bsc/signal.h
+++ b/include/osmocom/bsc/signal.h
@@ -104,6 +104,7 @@ enum signal_ipaccess {
 
 enum signal_global {
 	S_GLOBAL_BTS_CLOSE_OM,
+	S_GLOBAL_BTS_NEW,
 };
 
 /* SS_RF signals */