initial commit

Makefile

@@ -0,0 +1,21 @@
+CC = gcc
+OUT = dnstun
+OBJS = dnstun.o tun.o
+
+LDFLAGS = 
+CFLAGS = -c -g -Wall 
+
+$(OUT): $(OBJS)
+	$(CC) $(OBJS) -o $(OUT) $(LDFLAGS)
+
+%.o : %.c %.h
+	$(CC) $(CFLAGS) $< -o $@
+
+clean:
+	rm -f $(OUT)
+	rm -f *~
+	rm -f *.o
+	rm -f *.core
+
+run: $(OUT)
+	./$(OUT)

dnstun.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+
+#include "tun.h"
+
+int
+main()
+{
+	open_tun();
+
+	sleep(10);
+
+	close_tun();	
+
+	return 0;
+}

tun.c

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <err.h>
+
+#include "tun.h"
+
+#define TUN_MAX_TRY 50
+
+int tun_fd = -1;
+char *tun_device = NULL;
+
+#ifdef LINUX
+
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <linux/if_tun.h>
+
+int 
+open_tun() 
+{
+	struct ifreq ifreq;
+	int i;
+
+	if (tun_device == NULL)
+		tun_device = "/dev/net/tun";
+
+	if ((tun_fd = open(tun_device, O_RDWR)) < 0) 
+		err(1, "open_tun: %s: %s", tun_device, strerror(errno));
+
+	bzero(&ifreq, sizeof(ifreq));
+
+	ifreq.ifr_flags = IFF_TUN; 
+
+	for (i = 0; i < TUN_MAX_TRY; i++) {
+		snprintf(ifreq.ifr_name, IFNAMSIZ, "tun%d", i);
+
+		if (ioctl(tun_fd, TUNSETIFF, (void *) &ifreq) != -1) {
+			printf("opened %s\n", ifreq.ifr_name);
+			return 0;
+		}
+
+		if (errno != EBUSY) 
+			err(1, "open_tun: ioctl[TUNSETIFF]: %s", strerror(errno));
+	}
+
+	err(1, "open_tun: Couldn't set interface name.\n");
+
+	return 1;
+}
+
+#else /* BSD */
+
+int 
+open_tun() 
+{
+	if (tun_device != NULL) {
+		if ((tun_fd = open(tun_device, O_RDWR)) < 0) 
+			err(1, "open_tun: %s: %s", tun_device, strerror(errno));
+	} else {
+		char tun_name[50];
+		int i;
+
+		for (i = 0; i < TUN_MAX_TRY; i++) {
+			snprintf(tun_name, sizeof(tun_name), "/dev/tun%d", i);
+
+			if ((tun_fd = open(tun_name, O_RDWR)) >= 0)
+				return 0;
+
+			if (errno == ENOENT)
+				break;
+		}
+
+		err(1, "open_tun: Failed to open tunneling device.");
+	}
+
+	return 0;
+}
+
+#endif /* LINUX */
+
+void 
+close_tun() 
+{
+	if (tun_fd >= 0)
+		close(tun_fd);
+}
+
+int 
+write_tun(u_char *buf, int len) 
+{
+	if (write(tun_fd, buf, len) != len) 
+		err(1, "write_tun: %s", strerror(errno));
+
+	return 0;
+}
+
+int 
+read_tun(u_char *buf, int len) 
+{
+	return read(tun_fd, buf, len);
+}
+

tun.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2006 Bjorn Andersson <flex@kryo.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _TUN_H_
+#define _TUN_H_
+
+extern char *tun_device;
+extern int tun_fd;
+
+extern int open_tun();
+extern void close_tun();
+extern int write_tun(u_char *buf, int len);
+extern int read_tun(u_char *buf, int len);
+
+#endif /* _TUN_H_ */