fixed tap device setup (requires open/close for each call)

using more meaningful names for tap devices

src/dumm/guest.c

@@ -79,7 +79,7 @@ static iface_t* create_iface(private_guest_t *this, char *name)
 	iterator = this->ifaces->create_iterator(this->ifaces, TRUE);
 	while (iterator->iterate(iterator, (void**)&iface))
 	{
-		if (streq(name, iface->get_guest(iface)))
+		if (streq(name, iface->get_guestif(iface)))
 		{
 			DBG1("guest '%s' already has an interface '%s'", this->name, name);
 			iterator->destroy(iterator);
@@ -88,7 +88,7 @@ static iface_t* create_iface(private_guest_t *this, char *name)
 	}
 	iterator->destroy(iterator);
 
-	iface = iface_create(name, this->mconsole);
+	iface = iface_create(this->name, name, this->mconsole);
 	if (iface)
 	{
 		this->ifaces->insert_last(this->ifaces, iface);

src/dumm/iface.c

@@ -19,6 +19,7 @@
 #include <sys/types.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <stdio.h>
 #include <net/if.h>
 #include <sys/ioctl.h>
 #include <linux/if_tun.h>
@@ -33,29 +34,27 @@ struct private_iface_t {
 	/** public interface */
 	iface_t public;
 	/** device name in guest (eth0) */
-	char *guest;
+	char *guestif;
 	/** device name at host (tap0) */
-	char *host;
-	/** tap device handle to manage taps */
-	int tap;
+	char *hostif;
 	/** mconsole for guest */
 	mconsole_t *mconsole;
 };
 
 /**
- * Implementation of iface_t.get_guest.
+ * Implementation of iface_t.get_guestif.
  */
-static char* get_guest(private_iface_t *this)
+static char* get_guestif(private_iface_t *this)
 {
-	return this->guest;
+	return this->guestif;
 }
 
 /**
- * Implementation of iface_t.get_host.
+ * Implementation of iface_t.get_hostif.
  */
-static char* get_host(private_iface_t *this)
+static char* get_hostif(private_iface_t *this)
 {
-	return this->host;
+	return this->hostif;
 }
 
 /**
@@ -64,37 +63,56 @@ static char* get_host(private_iface_t *this)
 static bool destroy_tap(private_iface_t *this)
 {
 	struct ifreq ifr;
+	int tap;
 
 	memset(&ifr, 0, sizeof(ifr));
 	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
-	strncpy(ifr.ifr_name, this->host, sizeof(ifr.ifr_name) - 1);
+	strncpy(ifr.ifr_name, this->hostif, sizeof(ifr.ifr_name) - 1);
 	
-	if (ioctl(this->tap, TUNSETIFF, &ifr) < 0 ||
-		ioctl(this->tap, TUNSETPERSIST, 0) < 0)
+	tap = open(TAP_DEVICE, O_RDWR);
+	if (tap < 0)
 	{
-		DBG1("removing %s failed: %m", this->host);
+		DBG1("unable to open tap device %s: %m", TAP_DEVICE);
 		return FALSE;
 	}
+	if (ioctl(tap, TUNSETIFF, &ifr) < 0 ||
+		ioctl(tap, TUNSETPERSIST, 0) < 0)
+	{
+		DBG1("removing %s failed: %m", this->hostif);
+		close(tap);
+		return FALSE;
+	}
+	close(tap);
 	return TRUE;
 }
 
 /**
  * create the tap device
  */
-static char* create_tap(private_iface_t *this)
+static char* create_tap(private_iface_t *this, char *guest)
 {
 	struct ifreq ifr;
+	int tap;
 
 	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 ||
-		ioctl(this->tap, TUNSETOWNER, 0))
+	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s-%s", guest, this->guestif);
+
+	tap = open(TAP_DEVICE, O_RDWR);
+	if (tap < 0)
+	{
+		DBG1("unable to open tap device %s: %m", TAP_DEVICE);
+		return NULL;
+	}
+	if (ioctl(tap, TUNSETIFF, &ifr) < 0 ||
+		ioctl(tap, TUNSETPERSIST, 1) < 0 ||
+		ioctl(tap, TUNSETOWNER, 0))
     {
 		DBG1("creating new tap device failed: %m");
+		close(tap);
 		return NULL;
     } 
+	close(tap);
 	return strdup(ifr.ifr_name);
 }
 
@@ -103,50 +121,40 @@ static char* create_tap(private_iface_t *this)
  */
 static void destroy(private_iface_t *this)
 {
-	this->mconsole->del_iface(this->mconsole, this->guest);
+	this->mconsole->del_iface(this->mconsole, this->guestif);
 	destroy_tap(this);
-	close(this->tap);
-	free(this->guest);
-	free(this->host);
+	free(this->guestif);
+	free(this->hostif);
 	free(this);
 }
 
 /**
  * create the iface instance
  */
-iface_t *iface_create(char *guest, mconsole_t *mconsole)
+iface_t *iface_create(char *guest, char *guestif, 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.get_hostif = (char*(*)(iface_t*))get_hostif;
+	this->public.get_guestif = (char*(*)(iface_t*))get_guestif;
 	this->public.destroy = (void*)destroy;
 
 	this->mconsole = mconsole;
-	this->tap = open(TAP_DEVICE, O_RDWR);
-	if (this->tap < 0)
+	this->guestif = strdup(guestif);
+	this->hostif = create_tap(this, guest);
+	if (this->hostif == NULL)
 	{
-		DBG1("unable to open tap device %s: %m", TAP_DEVICE);
+		destroy_tap(this);
+		free(this->guestif);
 		free(this);
 		return NULL;
 	}
-	this->guest = strdup(guest);
-	this->host = create_tap(this);
-	if (this->host == NULL)
+	if (!this->mconsole->add_iface(this->mconsole, this->guestif, this->hostif))
 	{
+		DBG1("creating interface '%s' in guest failed", this->guestif);
 		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->guestif);
+		free(this->hostif);
 		free(this);
 		return NULL;
 	}

src/dumm/iface.h

@@ -35,14 +35,14 @@ struct iface_t {
 	 *
 	 * @return		guest interface name
 	 */
-	char* (*get_guest)(iface_t *this);
+	char* (*get_guestif)(iface_t *this);
 	
 	/**
 	 * @brief Get the interface name at the host (e.g. tap0).
 	 *
 	 * @return		host interface (tap device) name
 	 */
-	char* (*get_host)(iface_t *this);
+	char* (*get_hostif)(iface_t *this);
 	
 	/*
 	bool (*up) (iface_t *this);
@@ -61,10 +61,11 @@ struct iface_t {
 /**
  * @brief Create a new interface for a guest
  *
- * @param guest		name of the interface in the guest
+ * @param guest		name of the guest for this interface
+ * @param guestif	name of the interface in the guest
  * @param mconsole	mconsole of guest
  * @return			interface descriptor, or NULL if failed
  */
-iface_t *iface_create(char *guest, mconsole_t *mconsole);
+iface_t *iface_create(char *guest, char *guestif, mconsole_t *mconsole);
 
 #endif /* IFACE_H */

src/dumm/main.c

@@ -151,7 +151,7 @@ static void add_if(guest_t *guest, char *name)
 	if (iface)
 	{
 		printf("created guest interface '%s' connected to '%s'\n",
-			   iface->get_guest(iface), iface->get_host(iface));
+			   iface->get_guestif(iface), iface->get_hostif(iface));
 	}
 	else
 	{
@@ -171,11 +171,11 @@ static void del_if(guest_t *guest, char *name)
 	iterator = guest->create_iface_iterator(guest);
 	while (iterator->iterate(iterator, (void**)&iface))
 	{
-		if (streq(name, iface->get_guest(iface)))
+		if (streq(name, iface->get_guestif(iface)))
 		{
 			iterator->remove(iterator);
 			printf("removing interface '%s' ('%s') from %s\n",
-				   iface->get_guest(iface), iface->get_host(iface),
+				   iface->get_guestif(iface), iface->get_hostif(iface),
 				   guest->get_name(guest));
 			iface->destroy(iface);
 			found = TRUE;
@@ -201,7 +201,7 @@ static void list_if(guest_t *guest)
 	iterator = guest->create_iface_iterator(guest);
 	while (iterator->iterate(iterator, (void**)&iface))
 	{
-		printf("'%s' => '%s'\n", iface->get_guest(iface), iface->get_host(iface));
+		printf("'%s' => '%s'\n", iface->get_guestif(iface), iface->get_hostif(iface));
 
 	}
 	iterator->destroy(iterator);
@@ -318,7 +318,8 @@ static void list(dumm_t *dumm)
 		ifaces = guest->create_iface_iterator(guest);
 		while (ifaces->iterate(ifaces, (void**)&iface))
 		{
-			printf("  '%s' => '%s'\n", iface->get_guest(iface), iface->get_host(iface));
+			printf("  '%s' => '%s'\n",
+				   iface->get_guestif(iface), iface->get_hostif(iface));
 		}
 		ifaces->destroy(ifaces);
 	}

src/dumm/mconsole.c

@@ -154,7 +154,7 @@ mconsole_t *mconsole_create(char *sock)
 	}
 	memset(&addr, 0, sizeof(addr));
 	addr.sun_family = AF_UNIX;
-	sprintf(&addr.sun_path[1], "%5d-%s", getpid(), sock);
+	snprintf(&addr.sun_path[1], sizeof(addr.sun_path), "%5d-%s", getpid(), sock);
 	if (bind(this->socket, (struct sockaddr*)&addr, sizeof(addr)) < 0)
 	{
 		DBG1("binding mconsole socket failed: %m");