GSMTAP: make remote host for Um logging configurable via VTY

So far, the only way to configure GSMTAP Um logging is to use the
cmdline argument '-i'.  Let's deprecate it, and add a VTY command
to allow setting the remote host from configuration file.

The legacy '-i' option, if provided, overrides the configuration
file option, and will also appear in 'write file'.

Change-Id: I17676a21c4e0c9cbc88f2c5c53a39c6c6c473ca1
Tweaked by: Vadim Yanitskiy <vyanitskiy@sysmocom.de>

3 files changed, 69 insertions, 10 deletions

diff --git a/include/osmo-bts/bts.h b/include/osmo-bts/bts.h
index 3adafcc0..be0222d2 100644
--- a/include/osmo-bts/bts.h
+++ b/include/osmo-bts/bts.h
@@ -346,6 +346,7 @@ struct gsm_bts {
 	/* GSMTAP Um logging (disabled by default) */
 	struct {
 		struct gsmtap_inst *inst;
+		char *remote_host;
 		uint32_t sapi_mask;
 		uint8_t sapi_acch;
 	} gsmtap;
diff --git a/src/common/main.c b/src/common/main.c
index 38f517c2..25033525 100644
--- a/src/common/main.c
+++ b/src/common/main.c
@@ -77,7 +77,6 @@ static void print_help()
 		"  -T	--timestamp		Prefix every log line with a timestamp\n"
 		"  -V	--version		Print version information and exit\n"
 		"  -e 	--log-level		Set a global log-level\n"
-		"  -i	--gsmtap-ip		The destination IP used for GSMTAP.\n"
 		"\nVTY reference generation:\n"
 		"	--vty-ref-mode MODE	VTY reference generation mode (e.g. 'expert').\n"
 		"	--vty-ref-xml		Generate the VTY reference XML output and exit.\n"
@@ -186,6 +185,8 @@ static void handle_options(int argc, char **argv)
 			break;
 		case 'i':
 			gsmtap_ip = optarg;
+			fprintf(stderr, "Command line argument '-i' is deprecated, use VTY "
+				"parameter 'gsmtap-remote-host %s' instead.\n", gsmtap_ip);
 			break;
 		case 't':
 			fprintf(stderr, "Command line argument '-t' is deprecated and does nothing, "
@@ -320,15 +321,6 @@ int bts_main(int argc, char **argv)
 		}
 	}
 
-        if (gsmtap_ip) {
-		g_bts->gsmtap.inst = gsmtap_source_init(gsmtap_ip, GSMTAP_UDP_PORT, 1);
-		if (g_bts->gsmtap.inst == NULL) {
-			fprintf(stderr, "Failed during gsmtap_init()\n");
-			exit(1);
-		}
-		gsmtap_source_add_sink(g_bts->gsmtap.inst);
-	}
-
 	if (bts_init(g_bts) < 0) {
 		fprintf(stderr, "unable to open bts\n");
 		exit(1);
@@ -358,6 +350,32 @@ int bts_main(int argc, char **argv)
 
 	write_pid_file("osmo-bts");
 
+	/* Accept a GSMTAP host from VTY config, but a commandline option overrides that. */
+	if (gsmtap_ip != NULL) {
+		if (g_bts->gsmtap.remote_host != NULL) {
+			LOGP(DLGLOBAL, LOGL_NOTICE,
+			     "Command line argument '-i %s' overrides "
+			     "'gsmtap-remote-host %s' from the config file\n",
+			     gsmtap_ip, g_bts->gsmtap.remote_host);
+			talloc_free(g_bts->gsmtap.remote_host);
+		}
+		g_bts->gsmtap.remote_host = talloc_strdup(g_bts, gsmtap_ip);
+	}
+
+	/* TODO: move this to gsm_bts_alloc() */
+	if (g_bts->gsmtap.remote_host != NULL) {
+		LOGP(DLGLOBAL, LOGL_NOTICE,
+		     "Setting up GSMTAP Um forwarding to '%s:%u'\n",
+		     g_bts->gsmtap.remote_host, GSMTAP_UDP_PORT);
+		g_bts->gsmtap.inst = gsmtap_source_init(g_bts->gsmtap.remote_host,
+							GSMTAP_UDP_PORT, 1);
+		if (g_bts->gsmtap.inst == NULL) {
+			fprintf(stderr, "Failed during gsmtap_source_init()\n");
+			exit(1);
+		}
+		gsmtap_source_add_sink(g_bts->gsmtap.inst);
+	}
+
 	bts_controlif_setup(g_bts, ctrl_vty_get_bind_addr(), OSMO_CTRL_PORT_BTS);
 
 	rc = telnet_init_dynif(tall_bts_ctx, NULL, vty_get_bind_addr(),
diff --git a/src/common/vty.c b/src/common/vty.c
index d60a2be9..bbd33f85 100644
--- a/src/common/vty.c
+++ b/src/common/vty.c
@@ -315,6 +315,10 @@ static void config_write_bts_single(struct vty *vty, const struct gsm_bts *bts)
 			bts->agch_queue.thresh_level, bts->agch_queue.low_level,
 			bts->agch_queue.high_level, VTY_NEWLINE);
 
+	if (bts->gsmtap.remote_host != NULL)
+		vty_out(vty, " gsmtap-remote-host %s%s",
+			bts->gsmtap.remote_host,
+			VTY_NEWLINE);
 	for (i = 0; i < sizeof(uint32_t) * 8; i++) {
 		if (bts->gsmtap.sapi_mask & ((uint32_t) 1 << i)) {
 			sapi_buf = get_value_string_or_null(gsmtap_sapi_names, i);
@@ -1826,6 +1830,40 @@ static struct gsm_lchan *resolve_lchan(const struct gsm_network *net,
 	"logical channel commands\n"	\
 	"logical channel number\n"
 
+DEFUN(cfg_bts_gsmtap_remote_host,
+      cfg_bts_gsmtap_remote_host_cmd,
+      "gsmtap-remote-host [HOSTNAME]",
+      "Enable GSMTAP Um logging (see also 'gsmtap-sapi')\n"
+      "Remote IP address or hostname ('localhost' if omitted)\n")
+{
+	struct gsm_bts *bts = vty->index;
+
+	osmo_talloc_replace_string(bts, &bts->gsmtap.remote_host,
+				   argc > 0 ? argv[0] : "localhost");
+
+	if (vty->type != VTY_FILE)
+		vty_out(vty, "%% This command requires restart%s", VTY_NEWLINE);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_bts_no_gsmtap_remote_host,
+      cfg_bts_no_gsmtap_remote_host_cmd,
+      "no gsmtap-remote-host",
+      NO_STR "Disable GSMTAP Um logging\n")
+{
+	struct gsm_bts *bts = vty->index;
+
+	if (bts->gsmtap.remote_host != NULL)
+		talloc_free(bts->gsmtap.remote_host);
+	bts->gsmtap.remote_host = NULL;
+
+	if (vty->type != VTY_FILE)
+		vty_out(vty, "%% This command requires restart%s", VTY_NEWLINE);
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_bts_gsmtap_sapi_all, cfg_bts_gsmtap_sapi_all_cmd,
 	"gsmtap-sapi (enable-all|disable-all)",
 	"Enable/disable sending of UL/DL messages over GSMTAP\n"
@@ -2237,6 +2275,8 @@ int bts_vty_init(void *ctx)
 	install_element(BTS_NODE, &cfg_bts_smscb_tgt_qlen_cmd);
 	install_element(BTS_NODE, &cfg_bts_smscb_qhyst_cmd);
 
+	install_element(BTS_NODE, &cfg_bts_gsmtap_remote_host_cmd);
+	install_element(BTS_NODE, &cfg_bts_no_gsmtap_remote_host_cmd);
 	install_element(BTS_NODE, &cfg_bts_gsmtap_sapi_all_cmd);
 	install_element(BTS_NODE, &cfg_bts_gsmtap_sapi_cmd);
 	install_element(BTS_NODE, &cfg_bts_no_gsmtap_sapi_cmd);