From: Philipp Tölke <toelke@in.tum.de>
Date: Mon, 28 Jun 2010 12:37:34 +0000 (+0000)
Subject: a first simple test-program for the vpn-functionality
X-Git-Tag: initial-import-from-subversion-38251~21159
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=bada4affc0b7d79f9fabba26ab2fb780ed22ae6a;p=oweals%2Fgnunet.git

a first simple test-program for the vpn-functionality
---

diff --git a/src/vpn/tun.c b/src/vpn/tun.c
new file mode 100644
index 000000000..6e184b079
--- /dev/null
+++ b/src/vpn/tun.c
@@ -0,0 +1,104 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+
+#include <linux/if.h>
+#include <linux/if_tun.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+int tun_alloc(char *dev) {
+	struct ifreq ifr;
+	int fd, err;
+
+	if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) {
+		fprintf(stderr, "open: %s\n", strerror(errno));
+		return -1;
+	}
+
+	memset(&ifr, 0, sizeof(ifr));
+
+	ifr.ifr_flags = IFF_TUN; 
+	if(*dev)
+		strncpy(ifr.ifr_name, dev, IFNAMSIZ);
+
+	if ((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
+		close(fd);
+		fprintf(stderr, "ioctl: %s\n", strerror(errno));
+		return err;
+	}
+	strcpy(dev, ifr.ifr_name);
+	return fd;
+}
+
+void n2o(fd) {
+	char buf[1024];
+	int r, w;
+	for(;;) {
+		r = read(fd, buf, 1024);
+		if (r < 0) {
+			fprintf(stderr, "n2o read: %s\n", strerror(errno));
+			exit(1);
+		}
+		if (r == 0) {
+			close(fd);
+			exit(0);
+		}
+		while (r > 0) {
+			w = write(1, buf, r);
+			if (w < 0) {
+				fprintf(stderr, "n2o write: %s\n", strerror(errno));
+				close(fd);
+				exit(1);
+			}
+			r -= w;
+		}
+	}
+}
+
+void o2n(fd) {
+	char buf[1024];
+	int r, w;
+	for(;;) {
+		r = read(0, buf, 1024);
+		if (r < 0) {
+			fprintf(stderr, "o2n read: %s\n", strerror(errno));
+			exit(1);
+		}
+		if (r == 0) {
+			close(fd);
+			exit(0);
+		}
+		while (r > 0) {
+			w = write(fd, buf, r);
+			if (w < 0) {
+				fprintf(stderr, "o2n write: %s\n", strerror(errno));
+				close(fd);
+				exit(1);
+			}
+			r -= w;
+		}
+	}
+}
+
+int main(int argc, char** argv) {
+	char name[IFNAMSIZ];
+	int fd;
+
+	memset(name, 0, IFNAMSIZ);
+
+	strncpy(name, "mynet", IFNAMSIZ);
+	fprintf(stderr, "fd = %d, name = %s\n", fd = tun_alloc(name), name);
+
+	if (fork() == 0)
+		n2o(fd);
+
+	o2n(fd);
+
+	return 0;
+}