Cell Broadcast: CBSP and CBCH scheduling support

This adds code to handle CBSP (Cell Broadcast Service Protocol)
from the CBC (Cell Broadcast Centre), as well as BSC-internal data
structures for scheduling the various SMSCB on the CBCH of each BTS.

There are currently one known shortcoming in the code: We don't yet
verify if keepalives are received within repetition period.

Change-Id: Ia0a0de862a104d0f447a5d6e56c7c83981b825c7

6 files changed, 118 insertions, 0 deletions

diff --git a/include/osmocom/bsc/Makefile.am b/include/osmocom/bsc/Makefile.am
index f44e7fc86..396604eb1 100644
--- a/include/osmocom/bsc/Makefile.am
+++ b/include/osmocom/bsc/Makefile.am
@@ -55,4 +55,5 @@ noinst_HEADERS = \
 	gsm_08_08.h \
 	penalty_timers.h \
 	osmo_bsc_lcls.h \
+	smscb.h \
 	$(NULL)
diff --git a/include/osmocom/bsc/bsc_msc_data.h b/include/osmocom/bsc/bsc_msc_data.h
index 56124830c..b9df4ba8f 100644
--- a/include/osmocom/bsc/bsc_msc_data.h
+++ b/include/osmocom/bsc/bsc_msc_data.h
@@ -150,6 +150,7 @@ struct bsc_msc_data {
 /*
  * Per BSC data.
  */
+struct bsc_cbc_link;
 struct osmo_bsc_data {
 	struct gsm_network *network;
 
@@ -167,6 +168,8 @@ struct osmo_bsc_data {
 	char *ussd_no_msc_txt;
 
 	char *acc_lst_name;
+
+	struct bsc_cbc_link *cbc;
 };
 
 
diff --git a/include/osmocom/bsc/debug.h b/include/osmocom/bsc/debug.h
index 326012185..adc6abbe1 100644
--- a/include/osmocom/bsc/debug.h
+++ b/include/osmocom/bsc/debug.h
@@ -27,6 +27,7 @@ enum {
 	DCHAN,
 	DTS,
 	DAS,
+	DCBS,
 	Debug_LastEntry,
 };
 
diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index d82d1bac8..8dfbc6425 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -14,6 +14,7 @@
 #include <osmocom/core/stat_item.h>
 #include <osmocom/gsm/bts_features.h>
 #include <osmocom/gsm/protocol/gsm_08_08.h>
+#include <osmocom/gsm/protocol/gsm_48_049.h>
 #include <osmocom/gsm/gsm0808.h>
 #include <osmocom/gsm/gsm48.h>
 #include <osmocom/core/fsm.h>
@@ -957,6 +958,53 @@ struct gsm_bts_ref {
 	struct gsm_bts *bts;
 };
 
+/* A single Page of a SMSCB message */
+struct bts_smscb_page {
+	/* SMSCB message we're part of */
+	struct bts_smscb_message *msg;
+	/* Page Number within message (1 to 15) */
+	uint8_t nr;
+	/* number of valid blocks in data (up to 4) */
+	uint8_t num_blocks;
+	/* up to four blocks of 22 bytes each */
+	uint8_t data[88];
+};
+
+/* A SMSCB message (received from CBSP) */
+struct bts_smscb_message {
+	/* entry in bts_smscb_chan_state.messages */
+	struct llist_head list;
+	struct {
+		/* input data from CBSP (CBC) side */
+		uint16_t msg_id;
+		uint16_t serial_nr;
+		enum cbsp_category category;
+		uint16_t rep_period;
+		uint16_t num_bcast_req;
+		uint8_t dcs;
+	} input;
+	/* how often have all pages of this message been broadcast? */
+	uint32_t bcast_count;
+	/* actual page data of this message */
+	uint8_t num_pages; /* up to 15 */
+	struct bts_smscb_page page[15];
+};
+
+/* per-channel (basic/extended) CBCH state for a single BTS */
+struct bts_smscb_chan_state {
+	/* back-pointer to BTS */
+	struct gsm_bts *bts;
+	/* list of bts_smscb_message */
+	struct llist_head messages;
+	/* scheduling array; pointer of SMSCB pages */
+	struct bts_smscb_page **sched_arr;
+	size_t sched_arr_size;
+	/* index of the next to be transmitted page into the scheduler array */
+	size_t next_idx;
+	/* number of messages we have to pause due to overflow */
+	uint8_t overflow;
+};
+
 /* One BTS */
 struct gsm_bts {
 	/* list header in net->bts_list */
@@ -1213,6 +1261,11 @@ struct gsm_bts {
 	struct load_counter chan_load_samples[7];
 	int chan_load_samples_idx;
 	uint8_t chan_load_avg; /* current channel load average in percent (0 - 100). */
+
+	/* cell broadcast system */
+	struct osmo_timer_list cbch_timer;
+	struct bts_smscb_chan_state cbch_basic;
+	struct bts_smscb_chan_state cbch_extended;
 };
 
 /* One rejected BTS */
diff --git a/include/osmocom/bsc/smscb.h b/include/osmocom/bsc/smscb.h
new file mode 100644
index 000000000..22a258da9
--- /dev/null
+++ b/include/osmocom/bsc/smscb.h
@@ -0,0 +1,59 @@
+#pragma once
+#include <osmocom/bsc/gsm_data.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/netif/stream.h>
+#include <osmocom/gsm/cbsp.h>
+
+struct bsc_cbc_link;
+
+/* smscb.c */
+void bts_smscb_del(struct bts_smscb_message *smscb, struct bts_smscb_chan_state *cstate,
+		   const char *reason);
+const char *bts_smscb_msg2str(const struct bts_smscb_message *smscb);
+struct bts_smscb_chan_state *bts_get_smscb_chan(struct gsm_bts *bts, bool extended);
+int cbsp_rx_decoded(struct bsc_cbc_link *cbc, const struct osmo_cbsp_decoded *dec);
+int cbsp_tx_restart(struct bsc_cbc_link *cbc, bool is_emerg);
+const char *bts_smscb_chan_state_name(const struct bts_smscb_chan_state *cstate);
+unsigned int bts_smscb_chan_load_percent(const struct bts_smscb_chan_state *cstate);
+unsigned int bts_smscb_chan_page_count(const struct bts_smscb_chan_state *cstate);
+void smscb_vty_init(void);
+
+/* cbch_scheduler.c */
+int bts_smscb_gen_sched_arr(struct bts_smscb_chan_state *cstate, struct bts_smscb_page ***arr_out);
+struct bts_smscb_page *bts_smscb_pull_page(struct bts_smscb_chan_state *cstate);
+void bts_smscb_page_done(struct bts_smscb_chan_state *cstate, struct bts_smscb_page *page);
+int bts_smscb_rx_cbch_load_ind(struct gsm_bts *bts, bool cbch_extended, bool is_overflow,
+			       uint8_t slot_count);
+void bts_cbch_timer_schedule(struct gsm_bts *bts);
+
+/* cbsp_link.c */
+struct bsc_cbc_link {
+	struct gsm_network *net;
+	struct {
+		/* hostname/IP of CBC */
+		char *cbc_hostname;
+		/* TCP port (Default: 48049) of CBC */
+		int cbc_port;
+		/* local listening port (0 for disabling local server) */
+		int listen_port;
+		/* local listening hostname/IP */
+		char *listen_hostname;
+	} config;
+	/* for handling inbound TCP connections */
+	struct {
+		struct osmo_stream_srv *srv;
+		struct osmo_stream_srv_link *link;
+		char *sock_name;
+		struct msgb *msg;
+	} server;
+	/* for handling outbound TCP connections */
+	struct {
+		struct osmo_stream_cli *cli;
+		char *sock_name;
+		struct msgb *msg;
+	} client;
+};
+void cbc_vty_init(void);
+int bsc_cbc_link_restart(void);
+int cbsp_tx_decoded(struct bsc_cbc_link *cbc, struct osmo_cbsp_decoded *decoded);
diff --git a/include/osmocom/bsc/vty.h b/include/osmocom/bsc/vty.h
index 7e3c5053c..10ce16b2d 100644
--- a/include/osmocom/bsc/vty.h
+++ b/include/osmocom/bsc/vty.h
@@ -24,6 +24,7 @@ enum bsc_vty_node {
 	OM2K_NODE,
 	OM2K_CON_GROUP_NODE,
 	BSC_NODE,
+	CBC_NODE,
 };
 
 struct log_info;