From 0cc70daec76f59571d56a96bd86a960e18d13e9f Mon Sep 17 00:00:00 2001
From: Giuseppe Lettieri <g.lettieri@iet.unipi.it>
Date: Wed, 3 Apr 2013 16:17:35 +0200
Subject: [PATCH] tunproxy

From Philippe Biondi and Felician Nemeth.
---
 planetlab/exp-tool/tunproxy.c | 141 ++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 planetlab/exp-tool/tunproxy.c

diff --git a/planetlab/exp-tool/tunproxy.c b/planetlab/exp-tool/tunproxy.c
new file mode 100644
index 000000000..0f3ab8190
--- /dev/null
+++ b/planetlab/exp-tool/tunproxy.c
@@ -0,0 +1,141 @@
+/*
+ * tunproxy.c --- small demo program for tunneling over UDP with tun/tap
+ *
+ * Copyright (C) 2003  Philippe Biondi <phil@secdev.org>
+ * Copyright (C) 2013  Felician Nemeth <nemethf@tmit.bme.hu>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation.
+ *
+ * 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
+ * Lesser General Public License for more details.
+ *
+ * http://www.secdev.org/projects/tuntap_udp/files/tunproxy.c
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+#include <net/if.h>
+#include <linux/if_tun.h>
+#include <getopt.h>
+#include <sys/ioctl.h>
+#include <errno.h>
+
+#define PERROR(x) do { perror(x); exit(1); } while (0)
+#define ERROR(x, args ...) do { fprintf(stderr,"ERROR:" x, ## args); exit(1); } while (0)
+
+extern void exit(int);
+
+void usage()
+{
+	fprintf(stderr, "Usage: tunproxy -t target_ip:port [-p local_port] [-e]\n");
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	struct sockaddr_in sin, sout, remote;
+	struct ifreq ifr;
+	int fd, s, remote_len, remote_port, local_port, l;
+	unsigned int soutlen;
+	char c, *p, *remote_ip = 0;
+	char buf[2000];
+	fd_set fdset;
+
+	int TUNMODE = IFF_TUN, DEBUG = 0;
+
+	while ((c = getopt(argc, argv, "t:p:ehd")) != -1) {
+		switch (c) {
+		case 'h':
+			usage();
+		case 'd':
+			DEBUG++;
+			break;
+		case 'p':
+			local_port = atoi(optarg);
+			break;
+		case 't':
+			p = memchr(optarg,':',16);
+			if (!p) ERROR("invalid argument : [%s]\n",optarg);
+			*p = 0;
+			remote_ip = optarg;
+			remote_port = atoi(p+1);
+			break;
+		case 'e':
+			TUNMODE = IFF_TAP;
+			break;
+		default:
+			usage();
+		}
+	}
+	if (remote_ip == 0) usage();
+
+	if ( (fd = open("/dev/net/tun",O_RDWR)) < 0) PERROR("open");
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = TUNMODE | IFF_NO_PI;
+	strncpy(ifr.ifr_name, "toto%d", IFNAMSIZ);
+	if (ioctl(fd, TUNSETIFF, (void *)&ifr) < 0) PERROR("ioctl");
+
+	printf("Allocated interface %s. Configure and use it\n", ifr.ifr_name);
+	
+	s = socket(PF_INET, SOCK_DGRAM, 0);
+	sin.sin_family = AF_INET;
+	sin.sin_addr.s_addr = htonl(INADDR_ANY);
+	sin.sin_port = htons(local_port);
+
+	if ( bind(s,(struct sockaddr *)&sin, sizeof(sin)) < 0)
+	  PERROR("bind");
+
+	remote_len = sizeof(remote);
+	memset(&remote, 0, remote_len);
+	remote.sin_family = AF_INET;
+	remote.sin_port = htons(remote_port);
+	remote.sin_addr.s_addr=inet_addr(remote_ip);
+
+	while (1) {
+		FD_ZERO(&fdset);
+		FD_SET(fd, &fdset);
+		FD_SET(s, &fdset);
+		if (select(fd+s+1, &fdset,NULL,NULL,NULL) < 0) PERROR("select");
+		if (FD_ISSET(fd, &fdset)) {
+			if (DEBUG)
+			  write(1,">", 1);
+			l = read(fd, buf, sizeof(buf));
+			if (l < 0) 
+			  PERROR("read");
+			if (sendto(s, buf, l, 0, (struct sockaddr *)&remote, remote_len) < 0)
+			  PERROR("sendto");
+		}
+		if (FD_ISSET(s, &fdset)) {
+			if (DEBUG) 
+			  write(1,"<", 1);
+			soutlen = sizeof(sout);
+			l = recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr *)&sout, &soutlen);
+			if (l == -1) {
+			  write(1,"(", 1);
+			  fprintf(stderr, "[%s,%d]", strerror(errno), l);
+			  continue;
+			}
+			if ((sout.sin_addr.s_addr != remote.sin_addr.s_addr) ||
+			    (sout.sin_port != remote.sin_port)) {
+			  printf("Got packet from  %s:%u instead of %s:%u\n", 
+				 inet_ntoa(sout.sin_addr), ntohs(sout.sin_port),
+				 inet_ntoa(remote.sin_addr), ntohs(remote.sin_port));
+			}
+			if (write(fd, buf, l) < 0) PERROR("write");
+		}
+	}
+}
-- 
2.43.0