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

1 files changed, 417 insertions, 0 deletions

diff --git a/src/osmo-bsc/cbsp_link.c b/src/osmo-bsc/cbsp_link.c
new file mode 100644
index 000000000..8840afa52
--- /dev/null
+++ b/src/osmo-bsc/cbsp_link.c
@@ -0,0 +1,417 @@
+/* CBSP (Cell Broadcast Service Protocol) Handling for OsmoBSC */
+/*
+ * (C) 2019 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#include <osmocom/bsc/gsm_data.h>
+#include <osmocom/bsc/vty.h>
+#include <osmocom/bsc/debug.h>
+#include <osmocom/bsc/smscb.h>
+#include <osmocom/bsc/bsc_msc_data.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/gsm/cbsp.h>
+
+/* if a CBC IP/port has been configured, we continuously try to re-establish the TCP
+ * connection (as a client) to the CBC.  If none has been configured, and we have a listen
+ * TCP port, we expect the CBC to connect to us.  If neither of the two is configured,
+ * CBSP is effectively disabled */
+
+/*********************************************************************************
+ * CBSP Server (inbound TCP connection from CBC)
+ *********************************************************************************/
+
+static int cbsp_srv_closed_cb(struct osmo_stream_srv *conn)
+{
+	struct bsc_cbc_link *cbc = osmo_stream_srv_get_data(conn);
+	//struct osmo_fd *ofd = osmo_stream_srv_get_ofd(conn);
+
+	LOGP(DCBS, LOGL_NOTICE, "CBSP Server lost connection from %s\n", cbc->server.sock_name);
+	talloc_free(cbc->server.sock_name);
+	cbc->server.sock_name = NULL;
+	cbc->server.srv = NULL;
+	return 0;
+}
+
+static int cbsp_srv_cb(struct osmo_stream_srv *conn)
+{
+	struct bsc_cbc_link *cbc = osmo_stream_srv_get_data(conn);
+	struct osmo_fd *ofd = osmo_stream_srv_get_ofd(conn);
+	struct osmo_cbsp_decoded *decoded;
+	struct msgb *msg;
+	int rc;
+
+	/* READ */
+	rc = osmo_cbsp_recv_buffered(cbc, ofd->fd, &msg, &cbc->server.msg);
+	if (rc <= 0) {
+		if (rc == -EAGAIN || rc == -EINTR) {
+			/* more data needs to be read */
+			return 0;
+		} else if (rc == -EPIPE || rc == -ECONNRESET) {
+			/* lost connection */
+		} else if (rc == 0) {
+			/* connection closed */
+		}
+		osmo_stream_srv_destroy(conn);
+		cbc->server.srv = NULL;
+		return -EBADF;
+	}
+	OSMO_ASSERT(msg);
+	decoded = osmo_cbsp_decode(conn, msg);
+	if (decoded) {
+		LOGP(DCBS, LOGL_DEBUG, "Received CBSP %s\n",
+			get_value_string(cbsp_msg_type_names, decoded->msg_type));
+		cbsp_rx_decoded(cbc, decoded);
+		talloc_free(decoded);
+	} else {
+		LOGP(DCBS, LOGL_ERROR, "Unable to decode CBSP %s: '%s'\n",
+			msgb_hexdump(msg), osmo_cbsp_errstr);
+	}
+	msgb_free(msg);
+	return 0;
+
+}
+
+static int cbsp_srv_link_accept_cb(struct osmo_stream_srv_link *link, int fd)
+{
+	struct bsc_cbc_link *cbc = osmo_stream_srv_link_get_data(link);
+	struct osmo_stream_srv *srv;
+
+	LOGP(DCBS, LOGL_INFO, "CBSP Server received inbound connection from CBC: %s\n",
+		osmo_sock_get_name2(fd));
+
+	if (cbc->server.srv) {
+		LOGP(DCBS, LOGL_NOTICE, "CBSP Server refusing further connection (%s) "
+		     "while we already have another connection (%s)\n",
+		     osmo_sock_get_name2(fd), cbc->server.sock_name);
+		return -1;
+	}
+
+	srv = osmo_stream_srv_create(cbc, link, fd, cbsp_srv_cb, cbsp_srv_closed_cb, cbc);
+	if (!srv) {
+		LOGP(DCBS, LOGL_ERROR, "Unable to create stream server for %s\n",
+			osmo_sock_get_name2(fd));
+		return -1;
+	}
+
+	cbc->server.srv = srv;
+	if (cbc->server.sock_name)
+		talloc_free(cbc->server.sock_name);
+	cbc->server.sock_name = osmo_sock_get_name(cbc, fd);
+	LOGP(DCBS, LOGL_NOTICE, "CBSP Server link established from CBC %s\n", cbc->server.sock_name);
+	/* TODO: introduce ourselves to the peer using some osmcoom extensions */
+	cbsp_tx_restart(cbc, false);
+	return 0;
+}
+
+/*********************************************************************************
+ * CBSP Client (outbound TCP connection to CBC)
+ *********************************************************************************/
+
+static int cbsp_client_connect_cb(struct osmo_stream_cli *cli)
+{
+	struct bsc_cbc_link *cbc = osmo_stream_cli_get_data(cli);
+	struct osmo_fd *ofd = osmo_stream_cli_get_ofd(cli);
+
+	if (cbc->client.sock_name)
+		talloc_free(cbc->client.sock_name);
+	cbc->client.sock_name = osmo_sock_get_name(cbc, ofd->fd);
+
+	LOGP(DCBS, LOGL_NOTICE, "CBSP Client connected to CBC: %s\n", cbc->client.sock_name);
+
+	/* TODO: introduce ourselves to the peer using some osmcoom extensions */
+	cbsp_tx_restart(cbc, false);
+
+	return 0;
+}
+
+static int cbsp_client_disconnect_cb(struct osmo_stream_cli *cli)
+{
+	struct bsc_cbc_link *cbc = osmo_stream_cli_get_data(cli);
+
+	LOGP(DCBS, LOGL_NOTICE, "CBSP Client lost connection to %s\n", cbc->client.sock_name);
+	talloc_free(cbc->client.sock_name);
+	cbc->client.sock_name = NULL;
+	return 0;
+}
+
+static int cbsp_client_read_cb(struct osmo_stream_cli *cli)
+{
+	struct bsc_cbc_link *cbc = osmo_stream_cli_get_data(cli);
+	struct osmo_fd *ofd = osmo_stream_cli_get_ofd(cli);
+	struct osmo_cbsp_decoded *decoded;
+	struct msgb *msg = NULL;
+	int rc;
+
+	/* READ */
+	rc = osmo_cbsp_recv_buffered(cbc, ofd->fd, &msg, &cbc->client.msg);
+	if (rc <= 0) {
+		if (rc == -EAGAIN || rc == -EINTR) {
+			/* more data needs to be read */
+			return 0;
+		} else if (rc == -EPIPE || rc == -ECONNRESET) {
+			/* lost connection */
+		} else if (rc == 0) {
+			/* connection closed */
+		}
+		osmo_stream_cli_reconnect(cli);
+		return -EBADF;
+	}
+	OSMO_ASSERT(msg);
+	decoded = osmo_cbsp_decode(cli, msg);
+	if (decoded) {
+		LOGP(DCBS, LOGL_DEBUG, "Received CBSP %s\n",
+			get_value_string(cbsp_msg_type_names, decoded->msg_type));
+		cbsp_rx_decoded(cbc, decoded);
+		talloc_free(decoded);
+	} else {
+		LOGP(DCBS, LOGL_ERROR, "Unable to decode CBSP %s: '%s'\n",
+			msgb_hexdump(msg), osmo_cbsp_errstr);
+	}
+	msgb_free(msg);
+	return 0;
+}
+
+int bsc_cbc_link_restart(void)
+{
+	struct bsc_cbc_link *cbc = bsc_gsmnet->bsc_data->cbc;
+
+	/* shut down client, if no longer configured */
+	if (cbc->client.cli && !cbc->config.cbc_hostname) {
+		LOGP(DCBS, LOGL_NOTICE, "Stopping CBSP client\n");
+		osmo_stream_cli_close(cbc->client.cli);
+		osmo_stream_cli_destroy(cbc->client.cli);
+		cbc->client.cli = NULL;
+	}
+
+	/* shut down server, if no longer configured */
+	if (cbc->config.listen_port == -1) {
+		if (cbc->server.srv || cbc->server.link)
+			LOGP(DCBS, LOGL_NOTICE, "Stopping CBSP server\n");
+		if (cbc->server.srv) {
+			osmo_stream_srv_destroy(cbc->server.srv);
+			cbc->server.srv = NULL;
+		}
+		if (cbc->server.link) {
+			osmo_stream_srv_link_close(cbc->server.link);
+			osmo_stream_srv_link_destroy(cbc->server.link);
+			cbc->server.link = NULL;
+		}
+	}
+
+	/* start client, if configured */
+	if (cbc->config.cbc_hostname) {
+		LOGP(DCBS, LOGL_NOTICE, "Starting CBSP Client (to CBC at %s:%u)\n",
+			cbc->config.cbc_hostname, cbc->config.cbc_port);
+		if (!cbc->client.cli) {
+			cbc->client.cli = osmo_stream_cli_create(cbc);
+			osmo_stream_cli_set_data(cbc->client.cli, cbc);
+			osmo_stream_cli_set_connect_cb(cbc->client.cli, cbsp_client_connect_cb);
+			osmo_stream_cli_set_disconnect_cb(cbc->client.cli, cbsp_client_disconnect_cb);
+			osmo_stream_cli_set_read_cb(cbc->client.cli, cbsp_client_read_cb);
+		}
+		/* CBC side */
+		osmo_stream_cli_set_addr(cbc->client.cli, cbc->config.cbc_hostname);
+		osmo_stream_cli_set_port(cbc->client.cli, cbc->config.cbc_port);
+		/* Close/Reconnect? */
+		osmo_stream_cli_open(cbc->client.cli);
+	}
+
+	/* start server, if configured */
+	if (cbc->config.listen_port != -1) {
+		LOGP(DCBS, LOGL_NOTICE, "Starting CBSP Server (bound to %s:%u)\n",
+			cbc->config.listen_hostname, cbc->config.listen_port);
+		if (!cbc->server.srv) {
+			cbc->server.link = osmo_stream_srv_link_create(cbc);
+			osmo_stream_srv_link_set_data(cbc->server.link, cbc);
+			osmo_stream_srv_link_set_accept_cb(cbc->server.link, cbsp_srv_link_accept_cb);
+		}
+		osmo_stream_srv_link_set_addr(cbc->server.link, cbc->config.listen_hostname);
+		osmo_stream_srv_link_set_port(cbc->server.link, cbc->config.listen_port);
+	}
+	return 0;
+}
+
+/*! Encode + Transmit a 'decoded' CBSP message over given CBC link
+ *  \param[in] cbc Data structure representing the BSCs link to the CBC
+ *  \param[in] cbsp Decoded CBSP message to be transmitted. Ownership is transferred.
+ *  \return 0 on success, negative otherwise */
+int cbsp_tx_decoded(struct bsc_cbc_link *cbc, struct osmo_cbsp_decoded *cbsp)
+{
+	struct msgb *msg;
+
+	msg = osmo_cbsp_encode(cbc, cbsp);
+	if (!msg) {
+		LOGP(DCBS, LOGL_ERROR, "Unable to encode CBSP Message Type %s: %s\n",
+			get_value_string(cbsp_msg_type_names, cbsp->msg_type), osmo_cbsp_errstr);
+		talloc_free(cbsp);
+		return -1;
+	}
+	if (cbc->client.cli)
+		osmo_stream_cli_send(cbc->client.cli, msg);
+	else if (cbc->server.srv)
+		osmo_stream_srv_send(cbc->server.srv, msg);
+	else {
+		LOGP(DCBS, LOGL_ERROR, "Discarding CBSP Message, link is down: %s\n", msgb_hexdump(msg));
+		msgb_free(msg);
+	}
+
+	talloc_free(cbsp);
+	return 0;
+}
+
+static struct bsc_cbc_link *vty_cbc_data(struct vty *vty)
+{
+	return bsc_gsmnet->bsc_data->cbc;
+}
+
+/*********************************************************************************
+ * VTY Interface (Configuration + Introspection)
+ *********************************************************************************/
+
+DEFUN(cfg_cbc, cfg_cbc_cmd,
+	"cbc", "Configure CBSP Link to Cell Broadcast Centre\n")
+{
+	vty->node = CBC_NODE;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_cbc_remote_ip, cfg_cbc_remote_ip_cmd,
+	"remote-ip A.B.C.D",
+	"IP Address of the Cell Broadcast Centre\n"
+	"IP Address of the Cell Broadcast Centre\n")
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+	osmo_talloc_replace_string(cbc, &cbc->config.cbc_hostname, argv[0]);
+	return CMD_SUCCESS;
+}
+DEFUN(cfg_cbc_no_remote_ip, cfg_cbc_no_remote_ip_cmd,
+	"no remote-ip",
+	NO_STR "Remove IP address of CBC; disables outbound CBSP connections\n")
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+	talloc_free(cbc->config.cbc_hostname);
+	cbc->config.cbc_hostname = NULL;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_cbc_remote_port, cfg_cbc_remote_port_cmd,
+	"remote-port <1-65535>",
+	"TCP Port number of the Cell Broadcast Centre (Default: 48049)\n"
+	"TCP Port number of the Cell Broadcast Centre (Default: 48049)\n")
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+	cbc->config.cbc_port = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_cbc_listen_port, cfg_cbc_listen_port_cmd,
+	"listen-port <1-65535>",
+	"Local TCP port at which BSC listens for incoming CBSP connections from CBC\n"
+	"Local TCP port at which BSC listens for incoming CBSP connections from CBC\n")
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+	cbc->config.listen_port = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+DEFUN(cfg_cbc_no_listen_port, cfg_cbc_no_listen_port_cmd,
+	"no listen-port",
+	NO_STR "Remove CBSP Listen Port; disables inbound CBSP connections\n")
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+	cbc->config.listen_port = -1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_cbc_listen_ip, cfg_cbc_listen_ip_cmd,
+	"listen-ip A.B.C.D",
+	"Local IP Address where BSC listens for incoming CBC connections (Default: 0.0.0.0)\n"
+	"Local IP Address where BSC listens for incoming CBC connections\n")
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+	osmo_talloc_replace_string(cbc, &cbc->config.listen_hostname, argv[0]);
+	return CMD_SUCCESS;
+}
+
+static struct cmd_node cbc_node = {
+	CBC_NODE,
+	"%s(config-cbc)# ",
+	1,
+};
+
+static int config_write_cbc(struct vty *vty)
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+
+	vty_out(vty, "cbc%s", VTY_NEWLINE);
+
+	if (cbc->config.cbc_hostname) {
+		vty_out(vty, " remote-ip %s%s", cbc->config.cbc_hostname, VTY_NEWLINE);
+		vty_out(vty, " remote-port %u%s", cbc->config.cbc_port, VTY_NEWLINE);
+	} else
+		vty_out(vty, " no remote-ip%s", VTY_NEWLINE);
+
+	if (cbc->config.listen_port >= 0) {
+		vty_out(vty, " listen-port %u%s", cbc->config.listen_port, VTY_NEWLINE);
+		vty_out(vty, " listen-ip %s%s", cbc->config.listen_hostname, VTY_NEWLINE);
+	} else
+		vty_out(vty, " no listen-port%s", VTY_NEWLINE);
+
+	return 0;
+}
+
+DEFUN(show_cbc, show_cbc_cmd,
+	"show cbc",
+	SHOW_STR "Display state of CBC / CBSP\n")
+{
+	struct bsc_cbc_link *cbc = vty_cbc_data(vty);
+
+	if (!cbc->config.cbc_hostname)
+		vty_out(vty, "CBSP Client Config: Disabled%s", VTY_NEWLINE);
+	else {
+		vty_out(vty, "CBSP Client Config: CBC IP=%s, CBC Port=%u%s",
+			cbc->config.cbc_hostname, cbc->config.cbc_port, VTY_NEWLINE);
+		vty_out(vty, "CBSP Client Connection: %s%s",
+			cbc->client.sock_name ? cbc->client.sock_name : "Disconnected", VTY_NEWLINE);
+	}
+	if (cbc->config.listen_port < 0)
+		vty_out(vty, "CBSP Server Config: Disabled%s\n", VTY_NEWLINE);
+	else {
+		vty_out(vty, "CBSP Server Config: Listen IP=%s, Port=%u%s\n",
+			cbc->config.listen_hostname, cbc->config.listen_port, VTY_NEWLINE);
+		vty_out(vty, "CBSP Server Connection: %s%s",
+			cbc->server.sock_name ? cbc->server.sock_name : "Disconnected", VTY_NEWLINE);
+	}
+	return CMD_SUCCESS;
+}
+
+void cbc_vty_init(void)
+{
+	install_element(VIEW_NODE, &show_cbc_cmd);
+	install_element(CONFIG_NODE, &cfg_cbc_cmd);
+	install_node(&cbc_node, config_write_cbc);
+	install_element(CBC_NODE, &cfg_cbc_remote_ip_cmd);
+	install_element(CBC_NODE, &cfg_cbc_no_remote_ip_cmd);
+	install_element(CBC_NODE, &cfg_cbc_remote_port_cmd);
+	install_element(CBC_NODE, &cfg_cbc_listen_port_cmd);
+	install_element(CBC_NODE, &cfg_cbc_no_listen_port_cmd);
+	install_element(CBC_NODE, &cfg_cbc_listen_ip_cmd);
+}