added dynamic interface manipulation for guests

management of tap devices on the host

src/dumm/iface.c

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2007 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ * Copyright (C) 2002 Jeff Dike
+ *
+ * Based on the "tunctl" utlity from Jeff Dike.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <linux/if_tun.h>
+
+#include <debug.h>
+
+#include "iface.h"
+
+typedef struct private_iface_t private_iface_t;
+
+struct private_iface_t {
+	/** public interface */
+	iface_t public;
+	/** device name in guest (eth0) */
+	char *guest;
+	/** device name at host (tap0) */
+	char *host;
+	/** tap device handle to manage taps */
+	int tap;
+	/** mconsole for guest */
+	mconsole_t *mconsole;
+};
+
+/**
+ * Implementation of iface_t.get_guest.
+ */
+static char* get_guest(private_iface_t *this)
+{
+	return this->guest;
+}
+
+/**
+ * Implementation of iface_t.get_host.
+ */
+static char* get_host(private_iface_t *this)
+{
+	return this->host;
+}
+
+/**
+ * destroy the tap device
+ */
+static bool destroy_tap(private_iface_t *this)
+{
+	struct ifreq ifr;
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+	strncpy(ifr.ifr_name, this->host, sizeof(ifr.ifr_name) - 1);
+	
+	if (ioctl(this->tap, TUNSETIFF, &ifr) < 0 ||
+		ioctl(this->tap, TUNSETPERSIST, 0) < 0)
+	{
+		DBG1("removing %s failed: %m", this->host);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * create the tap device
+ */
+static char* create_tap(private_iface_t *this)
+{
+	struct ifreq ifr;
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+	
+	if (ioctl(this->tap, TUNSETIFF, &ifr) < 0 ||
+		ioctl(this->tap, TUNSETPERSIST, 1) < 0)
+    {
+		DBG1("creating new tap device failed: %m");
+		return NULL;
+    } 
+	return strdup(ifr.ifr_name);
+}
+
+/**
+ * Implementation of iface_t.destroy.
+ */
+static void destroy(private_iface_t *this)
+{
+	this->mconsole->del_iface(this->mconsole, this->guest);
+	destroy_tap(this);
+	close(this->tap);
+	free(this->guest);
+	free(this->host);
+	free(this);
+}
+
+/**
+ * create the iface instance
+ */
+iface_t *iface_create(char *guest, mconsole_t *mconsole)
+{
+	private_iface_t *this = malloc_thing(private_iface_t);
+	
+	this->public.get_host = (char*(*)(iface_t*))get_host;
+	this->public.get_guest = (char*(*)(iface_t*))get_guest;
+	this->public.destroy = (void*)destroy;
+
+	this->mconsole = mconsole;
+	this->tap = open(TAP_DEVICE, O_RDWR);
+	if (this->tap < 0)
+	{
+		DBG1("unable to open tap device %s: %m", TAP_DEVICE);
+		free(this);
+		return NULL;
+	}
+	this->guest = strdup(guest);
+	this->host = create_tap(this);
+	if (this->host == NULL)
+	{
+		destroy_tap(this);
+		close(this->tap);
+		free(this->guest);
+		free(this);
+		return NULL;
+	}
+	if (!this->mconsole->add_iface(this->mconsole, this->guest, this->host))
+	{
+		DBG1("creating interface '%s' in guest failed", this->guest);
+		destroy_tap(this);
+		close(this->tap);
+		free(this->guest);
+		free(this->host);
+		free(this);
+		return NULL;
+	}
+	return &this->public;
+}
+