libtap: add knet_tap_find, switch to ifname macro

also revert a0cbd79 to fix unnamed tap device creation

Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>

libtap/libtap.c

@@ -211,6 +211,37 @@ static int tap_get_mac_unsafe(const knet_tap_t knet_tap, char **ether_addr)
 	return err;
 }
 
+knet_tap_t knet_tap_find(char *dev, size_t dev_size)
+{
+	knet_tap_t knet_tap;
+
+	if (dev == NULL) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	if (dev_size < IFNAMSIZ) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	if (strlen(dev) > IFNAMSIZ) {
+		errno = E2BIG;
+		return NULL;
+	}
+
+	pthread_mutex_lock(&tap_mutex);
+
+	knet_tap = tap_cfg.tap_head;
+	while (knet_tap != NULL) {
+		if (!strcmp(dev, knet_tap->ifname))
+			break;
+		knet_tap = knet_tap->next;
+	}
+
+	pthread_mutex_unlock(&tap_mutex);
+	return knet_tap;
+}
 
 knet_tap_t knet_tap_open(char *dev, size_t dev_size)
 {
@@ -243,17 +274,19 @@ knet_tap_t knet_tap_open(char *dev, size_t dev_size)
 	if ((knet_tap->knet_tap_fd = open("/dev/net/tun", O_RDWR)) < 0)
 		goto out_error;
 
-	strncpy(knet_tap->ifr.ifr_name, dev, IFNAMSIZ);
+	strncpy(knet_tap->ifname, dev, IFNAMSIZ);
 	knet_tap->ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 
 	if (ioctl(knet_tap->knet_tap_fd, TUNSETIFF, &knet_tap->ifr) < 0)
 		goto out_error;
 
-	if ((strlen(dev) > 0) && (strcmp(dev, knet_tap->ifr.ifr_name) != 0)) {
+	if ((strlen(dev) > 0) && (strcmp(dev, knet_tap->ifname) != 0)) {
 		errno = EBUSY;
 		goto out_error;
 	}
 
+	strcpy(dev, knet_tap->ifname);
+
 	if (!tap_init) {
 		tap_cfg.tap_head = NULL;
 		tap_cfg.tap_sockfd = socket(AF_INET, SOCK_STREAM, 0);
@@ -298,7 +331,7 @@ void knet_tap_close(knet_tap_t knet_tap)
 
 	pthread_mutex_lock(&tap_mutex);
 
-	while (temp != knet_tap) {
+	while ((temp) && (temp != knet_tap)) {
 		prev = temp;
 		temp = temp->next;
 	}
@@ -506,13 +539,13 @@ static int tap_set_ip(knet_tap_t knet_tap, const char *command,
 		snprintf(cmdline, sizeof(cmdline)-1,
 			"ip addr %s %s/%s dev %s broadcast %s",
 			 command, ip_addr, prefix,
-			 knet_tap->ifr.ifr_name, broadcast);
+			 knet_tap->ifname, broadcast);
 		free(broadcast);
 	} else {
 		snprintf(cmdline, sizeof(cmdline)-1,
 			"ip addr %s %s/%s dev %s",
 			command, ip_addr, prefix,
-			knet_tap->ifr.ifr_name);
+			knet_tap->ifname);
 	}
 
 	return tap_execute_shell(cmdline);

libtap/libtap.h

@@ -6,6 +6,8 @@ typedef struct knet_tap *knet_tap_t;
 knet_tap_t knet_tap_open(char *dev, size_t dev_size);
 void knet_tap_close(knet_tap_t knet_tap);
 
+knet_tap_t knet_tap_find(char *dev, size_t dev_size);
+
 int knet_tap_get_fd(const knet_tap_t knet_tap);
 
 int knet_tap_get_mtu(const knet_tap_t knet_tap);

libtap/libtap_private.h

@@ -11,6 +11,8 @@ struct knet_tap {
 	struct knet_tap *next;
 };
 
+#define ifname ifr.ifr_name
+
 struct tap_config {
 	struct knet_tap *tap_head;
 	int tap_sockfd;

tests/tap_test.c

@@ -46,46 +46,33 @@ static int is_if_in_system(char *name)
 static int test_iface(char *name, size_t size)
 {
 	knet_tap_t knet_tap;
-	char *oldname = NULL;
-
-	if ((name) && (strlen(name))) {
-		oldname = strdup(name);
-		if (!oldname) {
-			log_error("Not enough memory to run the test");
-			exit(1);
-		}
-	}
 
 	knet_tap=knet_tap_open(name, size);
 	if (!knet_tap) {
 		if (tap_cfg.tap_sockfd < 0)
 			log_error("Unable to open knet_socket");
 		log_error("Unable to open knet.");
-		if (oldname)
-			free(oldname);
 		return -1;
 	}
 	log_info("Created interface: %s", name);
 
-	if (oldname) {
-		if (strcmp(oldname, name) != 0)
-			log_error("New name does NOT match request name... NOT FATAL");
-	}
-
 	if (is_if_in_system(name) > 0) {
 		log_info("Found interface %s on the system", name);
 	} else {
 		log_info("Unable to find interface %s on the system", name);
 	}
 
+	if (!knet_tap_find(name, size)) {
+		log_info("Unable to find interface %s in tap db", name);
+	} else {
+		log_info("Found interface %s in tap db", name);
+	}
+
 	knet_tap_close(knet_tap);
 
 	if (is_if_in_system(name) == 0)
 		log_info("Successfully removed interface %s from the system", name);
 
-	if (oldname)
-		free(oldname);
-
 	return 0;
 }