Introduce --gsmtap-ip/-i option

This option allows user to use custom IP address instead of default "localhost".
Correspondingly gsmtap init moved from sysmoBTS-specific code up to "bts" struct
level. This way it can be easier reused by other implementations. The
lack of regressions was verified by checking following command on
sysmoBTS: "./osmo-pcu -c osmo-pcu.cfg -r 1 -i 192.168.10.1" where
192.168.10.1 is the host which was running wireshark and netcat:
"nc -u -l 192.168.10.1 -p 4729" to accept gsmtap flow.

src/bts.h

@@ -27,6 +27,7 @@ extern "C" {
 #include <osmocom/core/rate_ctr.h>
 #include <osmocom/core/stat_item.h>
 #include <osmocom/core/timer.h>
+#include <osmocom/core/gsmtap.h>
 }
 
 #include "poll_controller.h"
@@ -172,6 +173,7 @@ struct gprs_rlcmac_bts {
 	uint8_t n3101;
 	uint8_t n3103;
 	uint8_t n3105;
+	struct gsmtap_inst *gsmtap;
 	struct gprs_rlcmac_trx trx[8];
 	int (*alloc_algorithm)(struct gprs_rlcmac_bts *bts,
 		struct GprsMs *ms,

src/pcu_l1_if.cpp

@@ -42,7 +42,7 @@ extern "C" {
 
 // FIXME: move this, when changed from c++ to c.
 extern "C" {
-void *l1if_open_pdch(void *priv, uint32_t hlayer1);
+void *l1if_open_pdch(void *priv, uint32_t hlayer1, struct gsmtap_inst *gsmtap);
 int l1if_connect_pdch(void *obj, uint8_t ts);
 int l1if_pdch_req(void *obj, uint8_t ts, int is_ptcch, uint32_t fn,
         uint16_t arfcn, uint8_t block_nr, uint8_t *data, uint8_t len);
@@ -436,7 +436,8 @@ bssgp_failed:
 				if (!bts->trx[trx].fl1h)
 					bts->trx[trx].fl1h = l1if_open_pdch(
 						(void *)trx,
-						info_ind->trx[trx].hlayer1);
+						info_ind->trx[trx].hlayer1,
+						bts->gsmtap);
 			if (!bts->trx[trx].fl1h) {
 				LOGP(DL1IF, LOGL_FATAL, "Failed to open direct "
 					"DSP access for PDCH.\n");

src/pcu_main.cpp

@@ -33,6 +33,8 @@ extern "C" {
 #include <osmocom/vty/telnet_interface.h>
 #include <osmocom/vty/logging.h>
 #include <osmocom/core/stats.h>
+#include <osmocom/core/gsmtap.h>
+#include <osmocom/core/gsmtap_util.h>
 }
 
 extern struct gprs_nsvc *nsvc;
@@ -44,6 +46,7 @@ void *tall_pcu_ctx;
 extern void *bv_tall_ctx;
 static int quit = 0;
 static int rt_prio = -1;
+static char *gsmtap_addr = "localhost"; // FIXME: use gengetopt's default value instead
 
 static void print_help()
 {
@@ -58,6 +61,7 @@ static void print_help()
 		"  -V   --version	print version\n"
 		"  -r   --realtime PRIO Use SCHED_RR with the specified "
 			"priority\n"
+		"  -i	--gsmtap-ip	The destination IP used for GSMTAP.\n"
 		);
 }
 
@@ -74,10 +78,11 @@ static void handle_options(int argc, char **argv)
 			{ "version", 0, 0, 'V' },
 			{ "realtime", 1, 0, 'r' },
 			{ "exit", 0, 0, 'e' },
+			{ "gsmtap-ip", 1, 0, 'i' },
 			{ 0, 0, 0, 0 }
 		};
 
-		c = getopt_long(argc, argv, "hc:m:n:Vr:e",
+		c = getopt_long(argc, argv, "hc:m:n:Vr:e:i:",
 				long_options, &option_idx);
 		if (c == -1)
 			break;
@@ -102,6 +107,9 @@ static void handle_options(int argc, char **argv)
 			print_version(1);
 			exit(0);
 			break;
+		case 'i':
+			gsmtap_addr = optarg;
+			break;
 		case 'r':
 			rt_prio = atoi(optarg);
 			break;
@@ -219,6 +227,13 @@ int main(int argc, char *argv[])
 		exit(0);
 	}
 
+	bts->gsmtap = gsmtap_source_init(gsmtap_addr, GSMTAP_UDP_PORT, 1);
+
+	if (bts->gsmtap)
+		gsmtap_source_add_sink(bts->gsmtap);
+	else
+		fprintf(stderr, "Failed to initialize GSMTAP for %s\n", gsmtap_addr);
+
 	rc = vty_read_config_file(config_file, NULL);
 	if (rc < 0 && config_given) {
 		fprintf(stderr, "Failed to parse the config file: '%s'\n",

src/sysmo_l1_if.c

@@ -357,7 +357,7 @@ int l1if_pdch_req(void *obj, uint8_t ts, int is_ptcch, uint32_t fn,
 	return 0;
 }
 
-void *l1if_open_pdch(void *priv, uint32_t hlayer1)
+void *l1if_open_pdch(void *priv, uint32_t hlayer1, struct gsmtap_inst *gsmtap)
 {
 	struct femtol1_hdl *fl1h;
 	int rc;
@@ -378,9 +378,7 @@ void *l1if_open_pdch(void *priv, uint32_t hlayer1)
 		return NULL;
 	}
 
-	fl1h->gsmtap = gsmtap_source_init("localhost", GSMTAP_UDP_PORT, 1);
-	if (fl1h->gsmtap)
-		gsmtap_source_add_sink(fl1h->gsmtap);
+	fl1h->gsmtap = gsmtap;
 
 	return fl1h;
 }