Initial support for export + curses-visualization of measurements

This extends osmo_nitb to offer a UDP feed of real-time measurement
reports, which can be used by (a variety of) external tools for
visualization or other processing.

We also add a small ncurses based tool (meas_vis) which shows a
baragraph display of the last few mobile stations that were active,
indicating their uplink/downlink receive level and quality.

<WARNING>
This sends non-portable structures like gsm_meas_rep over UDP
and assumes the receiver has identical alignment and endianness!  Before
this feature is merged, it either needs to be converted to a unix domain
socket (but they don't do multicast, which would be nice) or the wire
format needs to change into something portable with defined alignment
and encoding
</WARNING>
diff --git a/openbsc/src/libmsc/Makefile.am b/openbsc/src/libmsc/Makefile.am
index 24db2c2..aa7d8ae 100644
--- a/openbsc/src/libmsc/Makefile.am
+++ b/openbsc/src/libmsc/Makefile.am
@@ -2,6 +2,8 @@
 AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOVTY_CFLAGS) \
 	$(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS)
 
+noinst_HEADERS = meas_feed.h
+
 noinst_LIBRARIES = libmsc.a
 
 libmsc_a_SOURCES =	auth.c \
@@ -17,9 +19,9 @@
 			ussd.c \
 			vty_interface_layer3.c \
 			transaction.c \
-			osmo_msc.c ctrl_commands.c
+			osmo_msc.c ctrl_commands.c meas_feed.c
 
 if BUILD_SMPP
-noinst_HEADERS = smpp_smsc.h
+noinst_HEADERS += smpp_smsc.h
 libmsc_a_SOURCES += smpp_smsc.c smpp_openbsc.c smpp_vty.c smpp_utils.c
 endif
diff --git a/openbsc/src/libmsc/meas_feed.c b/openbsc/src/libmsc/meas_feed.c
new file mode 100644
index 0000000..8466c76
--- /dev/null
+++ b/openbsc/src/libmsc/meas_feed.c
@@ -0,0 +1,158 @@
+/* UDP-Feed of measurement reports */
+
+#include <unistd.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/write_queue.h>
+#include <osmocom/core/talloc.h>
+
+#include <osmocom/vty/command.h>
+#include <osmocom/vty/vty.h>
+
+#include <openbsc/meas_rep.h>
+#include <openbsc/signal.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/meas_feed.h>
+#include <openbsc/vty.h>
+
+#include "meas_feed.h"
+
+struct meas_feed_state {
+	struct osmo_wqueue wqueue;
+	char scenario[31+1];
+	char *dst_host;
+	uint16_t dst_port;
+};
+
+
+static struct meas_feed_state g_mfs;
+
+static int process_meas_rep(struct gsm_meas_rep *mr)
+{
+	struct msgb *msg;
+	struct meas_feed_meas *mfm;
+	struct gsm_subscriber *subscr;
+
+	/* ignore measurements as long as we don't know who it is */
+	if (!mr->lchan || !mr->lchan->conn || !mr->lchan->conn->subscr)
+		return 0;
+
+	subscr = mr->lchan->conn->subscr;
+
+	msg = msgb_alloc(sizeof(struct meas_feed_meas), "Meas. Feed");
+	if (!msg)
+		return 0;
+
+	/* fill in the header */
+	mfm = (struct meas_feed_meas *) msgb_put(msg, sizeof(*mfm));
+	mfm->hdr.msg_type = MEAS_FEED_MEAS;
+	mfm->hdr.version = MEAS_FEED_VERSION;
+
+	/* fill in MEAS_FEED_MEAS specific header */
+	strncpy(mfm->imsi, subscr->imsi, sizeof(mfm->imsi)-1);
+	mfm->imsi[sizeof(mfm->imsi)-1] = '\0';
+	strncpy(mfm->name, subscr->name, sizeof(mfm->name)-1);
+	mfm->name[sizeof(mfm->name)-1] = '\0';
+	strncpy(mfm->scenario, g_mfs.scenario, sizeof(mfm->scenario));
+	mfm->scenario[sizeof(mfm->scenario)-1] = '\0';
+
+	/* copy the entire measurement report */
+	memcpy(&mfm->mr, mr, sizeof(mfm->mr));
+
+	/* and send it to the socket */
+	osmo_wqueue_enqueue(&g_mfs.wqueue, msg);
+
+	return 0;
+}
+
+static int meas_feed_sig_cb(unsigned int subsys, unsigned int signal,
+			    void *handler_data, void *signal_data)
+{
+	struct lchan_signal_data *sdata = signal_data;
+
+	if (subsys != SS_LCHAN)
+		return 0;
+
+	if (signal == S_LCHAN_MEAS_REP)
+		process_meas_rep(sdata->mr);
+
+	return 0;
+}
+
+static int feed_write_cb(struct osmo_fd *ofd, struct msgb *msg)
+{
+	return write(ofd->fd, msgb_data(msg), msgb_length(msg));
+}
+
+static int feed_read_cb(struct osmo_fd *ofd, struct msgb *msg)
+{
+	int rc;
+	char buf[256];
+
+	rc = read(ofd->fd, buf, sizeof(buf));
+	ofd->fd &= ~BSC_FD_READ;
+
+	return rc;
+}
+
+int meas_feed_cfg_set(const char *dst_host, uint16_t dst_port)
+{
+	int rc;
+	int already_initialized = 0;
+
+	if (g_mfs.wqueue.bfd.fd)
+		already_initialized = 1;
+
+
+	if (already_initialized &&
+	    !strcmp(dst_host, g_mfs.dst_host) &&
+	    dst_port == g_mfs.dst_port)
+		return 0;
+
+	if (!already_initialized) {
+		osmo_wqueue_init(&g_mfs.wqueue, 10);
+		g_mfs.wqueue.write_cb = feed_write_cb;
+		g_mfs.wqueue.read_cb = feed_read_cb;
+		osmo_signal_register_handler(SS_LCHAN, meas_feed_sig_cb, NULL);
+	}
+
+	if (already_initialized) {
+		osmo_wqueue_clear(&g_mfs.wqueue);
+		osmo_fd_unregister(&g_mfs.wqueue.bfd);
+		close(g_mfs.wqueue.bfd.fd);
+		/* don't set to zero, as that would mean 'not yet initialized' */
+		g_mfs.wqueue.bfd.fd = -1;
+	}
+	rc = osmo_sock_init_ofd(&g_mfs.wqueue.bfd, AF_UNSPEC, SOCK_DGRAM,
+				IPPROTO_UDP, dst_host, dst_port,
+				OSMO_SOCK_F_CONNECT);
+	if (rc < 0)
+		return rc;
+
+	g_mfs.wqueue.bfd.when &= ~BSC_FD_READ;
+
+	if (g_mfs.dst_host)
+		talloc_free(g_mfs.dst_host);
+	g_mfs.dst_host = talloc_strdup(NULL, dst_host);
+	g_mfs.dst_port = dst_port;
+
+	return 0;
+}
+
+void meas_feed_cfg_get(char **host, uint16_t *port)
+{
+	*port = g_mfs.dst_port;
+	*host = g_mfs.dst_host;
+}
+
+void meas_feed_scenario_set(const char *name)
+{
+	strncpy(g_mfs.scenario, name, sizeof(g_mfs.scenario)-1);
+	g_mfs.scenario[sizeof(g_mfs.scenario)-1] = '\0';
+}
+
+const char *meas_feed_scenario_get(void)
+{
+	return g_mfs.scenario;
+}
diff --git a/openbsc/src/libmsc/meas_feed.h b/openbsc/src/libmsc/meas_feed.h
new file mode 100644
index 0000000..782a961
--- /dev/null
+++ b/openbsc/src/libmsc/meas_feed.h
@@ -0,0 +1,12 @@
+#ifndef _INT_MEAS_FEED_H
+#define _INT_MEAS_FEED_H
+
+#include <stdint.h>
+
+int meas_feed_cfg_set(const char *dst_host, uint16_t dst_port);
+void meas_feed_cfg_get(char **host, uint16_t *port);
+
+void meas_feed_scenario_set(const char *name);
+const char *meas_feed_scenario_get(void);
+
+#endif  /* _INT_MEAS_FEED_H */
diff --git a/openbsc/src/libmsc/vty_interface_layer3.c b/openbsc/src/libmsc/vty_interface_layer3.c
index f9213f5..06ef2d1 100644
--- a/openbsc/src/libmsc/vty_interface_layer3.c
+++ b/openbsc/src/libmsc/vty_interface_layer3.c
@@ -49,6 +49,8 @@
 #include <openbsc/mncc_int.h>
 #include <openbsc/handover.h>
 
+#include "meas_feed.h"
+
 extern struct gsm_network *gsmnet_from_vty(struct vty *v);
 
 static void subscr_dump_full_vty(struct vty *vty, struct gsm_subscriber *subscr, int pending)
@@ -947,6 +949,11 @@
 
 static int config_write_mncc_int(struct vty *vty)
 {
+	uint16_t meas_port;
+	char *meas_host;
+
+	meas_feed_cfg_get(&meas_host, &meas_port);
+
 	vty_out(vty, "mncc-int%s", VTY_NEWLINE);
 	vty_out(vty, " default-codec tch-f %s%s",
 		get_value_string(tchf_codec_names, mncc_int.def_codec[0]),
@@ -954,6 +961,10 @@
 	vty_out(vty, " default-codec tch-h %s%s",
 		get_value_string(tchh_codec_names, mncc_int.def_codec[1]),
 		VTY_NEWLINE);
+	if (meas_port)
+		vty_out(vty, " meas-feed destination %s %u%s",
+			meas_host, meas_port, VTY_NEWLINE);
+
 
 	return CMD_SUCCESS;
 }
@@ -994,6 +1005,28 @@
 	return CMD_SUCCESS;
 }
 
+DEFUN(mnccint_meas_feed, mnccint_meas_feed_cmd,
+	"meas-feed destination ADDR <0-65535>",
+	"FIXME")
+{
+	int rc;
+
+	rc = meas_feed_cfg_set(argv[0], atoi(argv[1]));
+	if (rc < 0)
+		return CMD_WARNING;
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(meas_feed_scenario, meas_feed_scenario_cmd,
+	"meas-feed scenario NAME",
+	"FIXME")
+{
+	meas_feed_scenario_set(argv[0]);
+
+	return CMD_SUCCESS;
+}
+
 int bsc_vty_init_extra(void)
 {
 	osmo_signal_register_handler(SS_SCALL, scall_cbfn, NULL);
@@ -1028,12 +1061,14 @@
 	install_element(ENABLE_NODE, &smsqueue_clear_cmd);
 	install_element(ENABLE_NODE, &smsqueue_fail_cmd);
 	install_element(ENABLE_NODE, &subscriber_send_pending_sms_cmd);
+	install_element(ENABLE_NODE, &meas_feed_scenario_cmd);
 
 	install_element(CONFIG_NODE, &cfg_mncc_int_cmd);
 	install_node(&mncc_int_node, config_write_mncc_int);
 	vty_install_default(MNCC_INT_NODE);
 	install_element(MNCC_INT_NODE, &mnccint_def_codec_f_cmd);
 	install_element(MNCC_INT_NODE, &mnccint_def_codec_h_cmd);
+	install_element(MNCC_INT_NODE, &mnccint_meas_feed_cmd);
 
 	install_element(CFG_LOG_NODE, &log_level_sms_cmd);