1 files changed, 125 insertions, 0 deletions
diff --git a/gssm/src/mktun/mktun.c b/gssm/src/mktun/mktun.c
new file mode 100644
index 0000000..e22d496
--- /dev/null
+++ b/gssm/src/mktun/mktun.c
@@ -0,0 +1,125 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <libgen.h>
+#include <getopt.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/if_tun.h>
+#include <linux/if.h>
+#include <linux/if_ether.h>
+#include <arpa/inet.h>
+
+
+static struct option long_options[] = {
+	{ "delete", no_argument, 0, 'd'},
+	{ "help", no_argument, 0, 'h'},
+	{ 0, 0, 0, 0}
+};
+
+
+void usage(char *prog) {
+
+	fprintf(stderr, "note: you must be root (except perhaps to delete "
+	   "the interface)\n");
+	fprintf(stderr, "usage: %s [--help | -h] | [--delete | -d] "
+	   "<interface_name>\n", basename(prog));
+	exit(-1);
+}
+
+
+int main(int argc, char **argv) {
+
+	struct ifreq ifr, ifw;
+	char if_name[IFNAMSIZ], *chan_name = "gsm";
+	int option_index = 0, c, delete_if = 0, persist = 1, fd, sd;
+
+	while((c = getopt_long(argc, argv, "dh?", long_options, &option_index))
+	   != -1) {
+		switch(c) {
+			case 'd':
+				delete_if = 1;
+				break;
+			case 'h':
+			case '?':
+			default:
+				usage(argv[0]);
+				break;
+		}
+	}
+
+	if(optind >= argc)
+		usage(argv[0]);
+
+	chan_name = argv[optind];
+
+	if(!delete_if && getuid() && geteuid())
+		usage(argv[0]);
+
+	// construct TUN interface
+	if((fd = open("/dev/net/tun", O_RDWR)) == -1) {
+		perror("open");
+		return -1;
+	}
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+	snprintf(ifr.ifr_name, IFNAMSIZ, "%s", chan_name);
+	if(ioctl(fd, TUNSETIFF, (void *)&ifr) == -1) {
+		perror("TUNSETIFF");
+		close(fd);
+		return -1;
+	}
+
+	// save actual name
+	memcpy(if_name, ifr.ifr_name, IFNAMSIZ);
+
+	if(delete_if)
+		persist = 0;
+
+	if(ioctl(fd, TUNSETPERSIST, (void *)persist) == -1) {
+		perror("TUNSETPERSIST");
+		close(fd);
+		return -1;
+	}
+
+	if(delete_if) {
+		close(fd);
+		return 0;
+	}
+
+	// set interface up
+	if((sd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
+		perror("socket");
+		close(fd);
+		return -1;
+	}
+
+	// get current flags
+	memset(&ifr, 0, sizeof(ifr));
+	strncpy(ifr.ifr_name, if_name, IFNAMSIZ - 1);
+	if(ioctl(sd, SIOCGIFFLAGS, &ifr) == -1) {
+		perror("SIOCGIFFLAGS");
+		close(sd);
+		close(fd);
+		return -1;
+	}
+
+	// set up
+	memset(&ifw, 0, sizeof(ifw));
+	strncpy(ifw.ifr_name, if_name, IFNAMSIZ - 1);
+	ifw.ifr_flags = ifr.ifr_flags | IFF_UP | IFF_RUNNING;
+	if(ioctl(sd, SIOCSIFFLAGS, &ifw) == -1) {
+		perror("SIOCSIFFLAGS");
+		close(sd);
+		close(fd);
+		return -1;
+	}
+
+	close(sd);
+	close(fd);
+
+	return 0;
+}