[bsc-nat] Start with a simple NAT/MUX for a BSC

Harald actually pointed out that this feature is just NAT. We want
to connect n-real BSCs to one BSC Mux. We will talk the ip.access
protocol and SCCP over of this link.

The mux will drop certain GSM messages (like the reset), it will
replace source local reference (NAT functionality) and it will handle
some GSM08.08 specially.

Get the thing started...

2 files changed, 119 insertions, 1 deletions

diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index 4ad019e86..40591397a 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -2,7 +2,7 @@ INCLUDES = $(all_includes) -I$(top_srcdir)/include
 AM_CFLAGS=-Wall
 
 sbin_PROGRAMS = bsc_hack bs11_config ipaccess-find ipaccess-config \
-                isdnsync bsc_mgcp bsc_msc_ip
+                isdnsync bsc_mgcp bsc_msc_ip bsc_nat
 noinst_LIBRARIES = libbsc.a libmsc.a libvty.a libsccp.a
 noinst_HEADERS = vty/cardshell.h
 
@@ -41,3 +41,6 @@ isdnsync_SOURCES = isdnsync.c
 
 bsc_mgcp_SOURCES = bsc_mgcp.c msgb.c talloc.c debug.c select.c timer.c telnet_interface.c
 bsc_mgcp_LDADD = libvty.a
+
+bsc_nat_SOURCES = nat/bsc_nat.c
+bsc_nat_LDADD = libbsc.a libsccp.a
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
new file mode 100644
index 000000000..b5ba8cef4
--- /dev/null
+++ b/openbsc/src/nat/bsc_nat.c
@@ -0,0 +1,115 @@
+/* BSC Multiplexer/NAT */
+
+/*
+ * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2010 by on-waves.com
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define _GNU_SOURCE
+#include <getopt.h>
+
+#include <openbsc/debug.h>
+
+static const char *config_file = "openbsc.cfg";
+static char *msc_address = "127.0.0.1";
+static struct in_addr local_addr;
+
+static void print_usage()
+{
+	printf("Usage: bsc_nat\n");
+}
+
+static void print_help()
+{
+	printf("  Some useful help...\n");
+	printf("  -h --help this text\n");
+	printf("  -d option --debug=DRLL:DCC:DMM:DRR:DRSL:DNM enable debugging\n");
+	printf("  -s --disable-color\n");
+	printf("  -c --config-file filename The config file to use.\n");
+	printf("  -m --msc=IP. The address of the MSC.\n");
+	printf("  -l --local=IP. The local address of the MGCP.\n");
+}
+
+static void handle_options(int argc, char** argv)
+{
+	while (1) {
+		int option_index = 0, c;
+		static struct option long_options[] = {
+			{"help", 0, 0, 'h'},
+			{"debug", 1, 0, 'd'},
+			{"config-file", 1, 0, 'c'},
+			{"disable-color", 0, 0, 's'},
+			{"timestamp", 0, 0, 'T'},
+			{"msc", 1, 0, 'm'},
+			{"local", 1, 0, 'l'},
+			{0, 0, 0, 0}
+		};
+
+		c = getopt_long(argc, argv, "hd:sTPc:m:l:",
+				long_options, &option_index);
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'h':
+			print_usage();
+			print_help();
+			exit(0);
+		case 's':
+			debug_use_color(0);
+			break;
+		case 'd':
+			debug_parse_category_mask(optarg);
+			break;
+		case 'c':
+			config_file = strdup(optarg);
+			break;
+		case 'T':
+			debug_timestamp(1);
+			break;
+		case 'm':
+			msc_address = strdup(optarg);
+			break;
+		case 'l':
+			inet_aton(optarg, &local_addr);
+			break;
+		default:
+			/* ignore */
+			break;
+		}
+	}
+}
+
+int main(int argc, char** argv)
+{
+	/* parse options */
+	handle_options(argc, argv);
+
+	/* seed the PRNG */
+	srand(time(NULL));
+
+	return 0;
+}