network: implement lxc_get_netdev_by_idx()

src/lxc/confile_utils.c

@@ -17,13 +17,22 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#include "config.h"
+
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "conf.h"
+#include "confile.h"
+#include "confile_utils.h"
+#include "error.h"
 #include "log.h"
+#include "list.h"
 #include "utils.h"
 
+lxc_log_define(lxc_confile_utils, lxc);
+
 int parse_idmaps(const char *idmap, char *type, unsigned long *nsid,
 		 unsigned long *hostid, unsigned long *range)
 {
@@ -156,3 +165,73 @@ bool lxc_config_value_empty(const char *value)
 
 	return true;
 }
+
+struct lxc_netdev *lxc_find_netdev_by_idx(struct lxc_conf *conf,
+					  unsigned int idx)
+{
+	struct lxc_netdev *netdev = NULL;
+	struct lxc_list *networks = &conf->network;
+	struct lxc_list *insert = networks;
+
+	/* lookup network */
+	if (lxc_list_empty(networks))
+		return NULL;
+
+	lxc_list_for_each(insert, networks) {
+		netdev = insert->elem;
+		if (netdev->idx >= idx)
+			break;
+	}
+
+	/* network already exists */
+	if (netdev->idx == idx)
+		return netdev;
+
+	return NULL;
+}
+
+/* Takes care of finding the correct netdev struct in the networks list or
+ * allocates a new one if it couldn't be found.
+ */
+struct lxc_netdev *lxc_get_netdev_by_idx(struct lxc_conf *conf,
+					 unsigned int idx)
+{
+	struct lxc_list *newlist;
+	struct lxc_netdev *netdev = NULL;
+	struct lxc_list *networks = &conf->network;
+	struct lxc_list *insert = networks;
+
+	/* lookup network */
+	netdev = lxc_find_netdev_by_idx(conf, idx);
+	if (netdev)
+		return netdev;
+
+	/* network does not exist */
+	netdev = malloc(sizeof(*netdev));
+	if (!netdev)
+		return NULL;
+
+	memset(netdev, 0, sizeof(*netdev));
+	lxc_list_init(&netdev->ipv4);
+	lxc_list_init(&netdev->ipv6);
+
+	/* give network a unique index */
+	netdev->idx = idx;
+
+	/* prepare new list */
+	newlist = malloc(sizeof(*newlist));
+	if (!newlist) {
+		free(netdev);
+		return NULL;
+	}
+
+	lxc_list_init(newlist);
+	newlist->elem = netdev;
+
+	/* Insert will now point to the correct position to insert the new
+	 * netdev.
+	 */
+	lxc_list_add_tail(insert, newlist);
+
+	return netdev;
+}

src/lxc/confile_utils.h

@@ -22,9 +22,15 @@
 
 #include <stdbool.h>
 
+#include "conf.h"
+
 extern int parse_idmaps(const char *idmap, char *type, unsigned long *nsid,
 			unsigned long *hostid, unsigned long *range);
 
 extern bool lxc_config_value_empty(const char *value);
+extern struct lxc_netdev *lxc_find_netdev_by_idx(struct lxc_conf *conf,
+						 unsigned int idx);
+extern struct lxc_netdev *lxc_get_netdev_by_idx(struct lxc_conf *conf,
+						unsigned int idx);
 
 #endif /* __LXC_CONFILE_UTILS_H */