From 0e193132f608d7f83a4ebc018eb6da3fc8ed359d Mon Sep 17 00:00:00 2001
From: Marcel Holtmann <marcel@holtmann.org>
Date: Thu, 16 Jul 2009 05:42:38 +0200
Subject: Add small test program for TUN/TAP devices

---
 tools/tap-test.c | 197 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 197 insertions(+)
 create mode 100644 tools/tap-test.c

(limited to 'tools/tap-test.c')

diff --git a/tools/tap-test.c b/tools/tap-test.c
new file mode 100644
index 00000000..357d41e9
--- /dev/null
+++ b/tools/tap-test.c
@@ -0,0 +1,197 @@
+/*
+ *
+ *  Connection Manager
+ *
+ *  Copyright (C) 2007-2009  Intel Corporation. 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 version 2 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 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 St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/poll.h>
+#include <sys/ioctl.h>
+
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <linux/if_tun.h>
+
+static int inet_ifup(const char *ifname)
+{
+	struct ifreq ifr;
+	int sk, err;
+
+	sk = socket(PF_INET, SOCK_DGRAM, 0);
+	if (sk < 0)
+		return -errno;
+
+	memset(&ifr, 0, sizeof(ifr));
+	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+
+	if (ioctl(sk, SIOCGIFFLAGS, &ifr) < 0) {
+		err = -errno;
+		goto done;
+	}
+
+	if (ifr.ifr_flags & IFF_UP) {
+		err = -EALREADY;
+		goto done;
+	}
+
+	ifr.ifr_flags |= IFF_UP;
+
+	if (ioctl(sk, SIOCSIFFLAGS, &ifr) < 0) {
+		err = -errno;
+		goto done;
+	}
+
+	err = 0;
+
+done:
+	close(sk);
+
+	return err;
+}
+
+static int create_tap(const char *ifname)
+{
+	struct ifreq ifr;
+	int fd, val;
+
+	fd = open("/dev/net/tun", O_RDWR);
+	if (fd < 0) {
+		perror("Failed to open TUN/TAP device");
+		return -1;
+	}
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+
+	if (ioctl(fd, TUNSETIFF, (void *) &ifr) < 0) {
+		perror("Failed to set TUN/TAP interface");
+		close(fd);
+		return -1;
+	}
+
+	val = ARPHRD_ETHER;
+
+	if (ioctl(fd, TUNSETLINK, (unsigned long) val) < 0)
+		perror("Failed to set TUN/TAP link type");
+
+	return fd;
+}
+
+static void dump_packet(unsigned char *buf, int len)
+{
+	int i;
+
+	printf("[");
+	for (i = 0; i < len; i++) {
+		printf(" %02x", buf[i]);
+		if ((i + 1) % 16 == 0)
+			printf("\n ");
+		else if ((i + 1) % 8 == 0)
+			printf(" ");
+	}
+	printf(" ]\n");
+}
+
+static void decode_ip(unsigned char *buf, int len)
+{
+	struct iphdr *ip = (void *) buf;
+
+	printf("    IP proto %d saddr 0x%08x daddr 0x%08x\n",
+					ip->protocol, ip->saddr, ip->daddr);
+}
+
+static void decode_packet(unsigned char *buf, int len)
+{
+	struct ether_header *eh = (void *) buf;
+	char src[18], dst[18];
+	uint16_t type;
+
+	snprintf(dst, sizeof(dst), "%02x:%02x:%02x:%02x:%02x:%02x",
+				eh->ether_dhost[0], eh->ether_dhost[1],
+				eh->ether_dhost[2], eh->ether_dhost[3],
+				eh->ether_dhost[4], eh->ether_dhost[5]);
+
+	snprintf(src, sizeof(src), "%02x:%02x:%02x:%02x:%02x:%02x",
+				eh->ether_shost[0], eh->ether_shost[1],
+				eh->ether_shost[2], eh->ether_shost[3],
+				eh->ether_shost[4], eh->ether_shost[5]);
+
+	type = ntohs(eh->ether_type);
+
+	printf("> type 0x%04x src %s dst %s <\n", type, src, dst);
+
+	switch (type) {
+	case ETHERTYPE_IP:
+		decode_ip(buf + 14, len - 14);
+		break;
+	case ETHERTYPE_LOOPBACK:
+		dump_packet(buf, len);
+		break;
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	const char *ifname = "xxx";
+	struct pollfd p;
+	int fd;
+
+	fd = create_tap(ifname);
+	if (fd < 0)
+		return 1;
+
+	if (inet_ifup(ifname) < 0) {
+		close(fd);
+		return 1;
+	}
+
+	memset(&p, 0, sizeof(p));
+	p.fd = fd;
+	p.events = POLLHUP | POLLIN;
+
+	while (1) {
+		unsigned char buf[2048];
+		int len;
+
+		len = poll(&p, 1, -1);
+		if (len < 0)
+			break;
+		if (len == 0)
+			continue;
+
+		len = read(fd, buf, sizeof(buf));
+		if (len < 0)
+			break;
+
+		decode_packet(buf, len);
+	}
+
+	return 0;
+}
-- 
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