From 0304e5f1d5c22089ea47de39d48958f5dd747fbe Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Fri, 15 Apr 2011 18:45:10 +0200
Subject: Save a list of interfaces managed by quicktun

---
 quicktun.c | 44 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/quicktun.c b/quicktun.c
index 4c5c585..50429a4 100644
--- a/quicktun.c
+++ b/quicktun.c
@@ -4,6 +4,7 @@
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/netdevice.h>
+#include <linux/rculist.h>
 #include <linux/udp.h>
 #include <net/dst.h>
 #include <net/genetlink.h>
@@ -23,6 +24,9 @@
 #define MAX_MTU 65535
 
 
+static LIST_HEAD(quicktun_list);
+
+
 struct quicktun_struct {
 	struct net_device	*dev;
 	unsigned long		flags;
@@ -34,6 +38,12 @@ struct quicktun_struct {
 };
 
 
+struct quicktun_list_entry {
+	struct list_head	list;
+	struct quicktun_struct	*quicktun;
+};
+
+
 static netdev_tx_t quicktun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct quicktun_struct *tun = netdev_priv(dev);
@@ -265,6 +275,7 @@ static int quicktun_cmd_create_device(struct sk_buff *skb, struct genl_info *inf
 	struct quicktun_struct *tun;
 	struct net *net = genl_info_net(info);
 	struct net_device *dev;
+	struct quicktun_list_entry *entry;
 	char *name = "qt%d";
 	int err;
 
@@ -286,16 +297,20 @@ static int quicktun_cmd_create_device(struct sk_buff *skb, struct genl_info *inf
 	if (info->attrs[QUICKTUN_A_IFNAME])
 		name = nla_data(info->attrs[QUICKTUN_A_IFNAME]);
 
+	entry = kmalloc(sizeof(struct quicktun_struct), GFP_KERNEL);
 	dev = alloc_netdev(sizeof(struct quicktun_struct), name, quicktun_setup);
 	
-	if (!dev)
-		return -ENOMEM;
+	if (!entry || !dev) {
+		err = -ENOMEM;
+		goto err_free;
+	}
 
 	dev_net_set(dev, net);
 
 	tun = netdev_priv(dev);
 	tun->dev = dev;
 	tun->flags = flags;
+	entry->quicktun = tun;
 
 	quicktun_net_init(dev);
 	
@@ -321,7 +336,7 @@ static int quicktun_cmd_create_device(struct sk_buff *skb, struct genl_info *inf
 
 	err = quicktun_socket_init(dev);
 	if (err < 0)
-		goto err_free_dev;
+		goto err_free;
 
 	rtnl_lock();
 
@@ -335,6 +350,8 @@ static int quicktun_cmd_create_device(struct sk_buff *skb, struct genl_info *inf
 	if (err < 0)
 		goto err_free_sk;
 
+	list_add_tail_rcu(&entry->list, &quicktun_list);
+
 	rtnl_unlock();
 
 	return 0;
@@ -343,8 +360,9 @@ static int quicktun_cmd_create_device(struct sk_buff *skb, struct genl_info *inf
 	rtnl_unlock();
 	sock_release(tun->sock);
 
- err_free_dev:
-	free_netdev(dev);
+ err_free:
+	if (dev) free_netdev(dev);
+	if (entry) kfree(entry);
 	return err;
 }
 
@@ -354,6 +372,7 @@ static int quicktun_cmd_delete_device(struct sk_buff *skb, struct genl_info *inf
 	struct net *net = genl_info_net(info);
 	struct net_device *dev;
 	struct quicktun_struct *tun;
+	struct quicktun_list_entry *entry = NULL;
 	struct socket *sock;
 	char *name;
 
@@ -381,12 +400,27 @@ static int quicktun_cmd_delete_device(struct sk_buff *skb, struct genl_info *inf
 	tun = netdev_priv(dev);
 	sock = tun->sock;
 
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(entry, &quicktun_list, list) {
+		if (entry->quicktun->dev == dev) {
+			break;
+		}
+	}
+
+	list_del_rcu(&entry->list);
+
+	rcu_read_unlock();
+
 	unregister_netdevice(dev);
 
 	rtnl_unlock();
 
 	sock_release(sock);
 
+	synchronize_rcu();
+	kfree(entry);
+
 	return 0;
 
 err_unlock:
-- 
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