[PATCH] tun driver use private linked list.

[Stephen Hemminger <shemminger@xxxxxxxx>]

Less grotty version, applies over earlier patch.
        - keep a private list.  
        - fix debug format strings.
        - drop the name entry in the private data structure since it already
          has a pointer to netdev that has name.

diff -Nru a/drivers/net/tun.c b/drivers/net/tun.c
--- a/drivers/net/tun.c Fri Aug  8 11:26:07 2003
+++ b/drivers/net/tun.c Fri Aug  8 11:26:07 2003
@@ -51,6 +51,8 @@
 
 /* Network device part of the driver */
 
+static LIST_HEAD(tun_dev_list);
+
 /* Net device open. */
 static int tun_net_open(struct net_device *dev)
 {
@@ -70,7 +72,7 @@
 {
        struct tun_struct *tun = (struct tun_struct *)dev->priv;
 
-       DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->name, skb->len);
+       DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 
        /* Drop packet if interface is not attached */
        if (!tun->attached)
@@ -120,7 +122,7 @@
 {
        struct tun_struct *tun = (struct tun_struct *)dev->priv;
    
-       DBG(KERN_INFO "%s: tun_net_init\n", tun->name);
+       DBG(KERN_INFO "%s: tun_net_init\n", tun->dev->name);
 
        switch (tun->flags & TUN_TYPE_MASK) {
        case TUN_TUN_DEV:
@@ -161,7 +163,7 @@
        if (!tun)
                return -EBADFD;
 
-       DBG(KERN_INFO "%s: tun_chr_poll\n", tun->name);
+       DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 
        poll_wait(file, &tun->read_wait, wait);
  
@@ -226,7 +228,7 @@
        if (!tun)
                return -EBADFD;
 
-       DBG(KERN_INFO "%s: tun_chr_write %d\n", tun->name, count);
+       DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 
        for (i = 0, len = 0; i < count; i++) {
                if (verify_area(VERIFY_READ, iv[i].iov_base, iv[i].iov_len))
@@ -290,7 +292,7 @@
        if (!tun)
                return -EBADFD;
 
-       DBG(KERN_INFO "%s: tun_chr_read\n", tun->name);
+       DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 
        for (i = 0, len = 0; i < count; i++) {
                if (verify_area(VERIFY_WRITE, iv[i].iov_base, iv[i].iov_len))
@@ -350,7 +352,7 @@
 
        tun->owner = -1;
        dev->init = tun_net_init;
-       tun->name = dev->name;
+
        SET_MODULE_OWNER(dev);
        dev->open = tun_net_open;
        dev->hard_start_xmit = tun_net_xmit;
@@ -359,27 +361,40 @@
        dev->destructor = (void (*)(struct net_device *))kfree;
 }
 
+static struct tun_struct *tun_get_by_name(const char *name)
+{
+       struct tun_struct *tun;
+
+       ASSERT_RTNL();
+       list_for_each_entry(tun, &tun_dev_list, list) {
+               if (!strncmp(tun->dev->name, name, IFNAMSIZ))
+                   return tun;
+       }
+
+       return NULL;
+}
+
 static int tun_set_iff(struct file *file, struct ifreq *ifr)
 {
        struct tun_struct *tun;
-       struct net_device *dev;
        int err;
 
-       dev = __dev_get_by_name(ifr->ifr_name);
-       if (dev) {
-               /* Device exist */
-               tun = dev->priv;
-
-               if (dev->init != tun_net_init || tun->attached)
+       tun = tun_get_by_name(ifr->ifr_name);
+       if (tun) {
+               if (tun->attached)
                        return -EBUSY;
 
                /* Check permissions */
-               if (tun->owner != -1)
-                       if (current->euid != tun->owner && 
!capable(CAP_NET_ADMIN))
-                               return -EPERM;
-       } else {
+               if (tun->owner != -1 &&
+                   current->euid != tun->owner && !capable(CAP_NET_ADMIN))
+                       return -EPERM;
+       } 
+       else if (__dev_get_by_name(ifr->ifr_name)) 
+               return -EINVAL;
+       else {
                char *name;
                unsigned long flags = 0;
+               struct net_device *dev;
 
                err = -EINVAL;
 
@@ -420,9 +435,10 @@
                        goto failed;
                }
        
+               list_add(&tun->list, &tun_dev_list);
        }
 
-       DBG(KERN_INFO "%s: tun_set_iff\n", tun->name);
+       DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 
        if (ifr->ifr_flags & IFF_NO_PI)
                tun->flags |= TUN_NO_PI;
@@ -433,7 +449,7 @@
        file->private_data = tun;
        tun->attached = 1;
 
-       strcpy(ifr->ifr_name, tun->name);
+       strcpy(ifr->ifr_name, tun->dev->name);
        return 0;
  failed:
        return err;
@@ -466,7 +482,7 @@
        if (!tun)
                return -EBADFD;
 
-       DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->name, cmd);
+       DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 
        switch (cmd) {
        case TUNSETNOCSUM:
@@ -477,7 +493,7 @@
                        tun->flags &= ~TUN_NOCHECKSUM;
 
                DBG(KERN_INFO "%s: checksum %s\n",
-                   tun->name, arg ? "disabled" : "enabled");
+                   tun->dev->name, arg ? "disabled" : "enabled");
                break;
 
        case TUNSETPERSIST:
@@ -488,14 +504,14 @@
                        tun->flags &= ~TUN_PERSIST;
 
                DBG(KERN_INFO "%s: persist %s\n",
-                   tun->name, arg ? "disabled" : "enabled");
+                   tun->dev->name, arg ? "disabled" : "enabled");
                break;
 
        case TUNSETOWNER:
                /* Set owner of the device */
                tun->owner = (uid_t) arg;
 
-               DBG(KERN_INFO "%s: owner set to %d\n", tun->owner);
+               DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, 
tun->owner);
                break;
 
 #ifdef TUN_DEBUG
@@ -519,7 +535,7 @@
        if (!tun)
                return -EBADFD;
 
-       DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->name, on);
+       DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 
        if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
                return ret; 
@@ -549,7 +565,7 @@
        if (!tun)
                return 0;
 
-       DBG(KERN_INFO "%s: tun_chr_close\n", tun->name);
+       DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
 
        tun_chr_fasync(-1, file, 0);
 
@@ -562,8 +578,10 @@
        /* Drop read queue */
        skb_queue_purge(&tun->readq);
 
-       if (!(tun->flags & TUN_PERSIST)) 
+       if (!(tun->flags & TUN_PERSIST)) {
+               list_del(&tun->list);
                unregister_netdevice(tun->dev);
+       }
 
        rtnl_unlock();
 
@@ -605,15 +623,14 @@
 
 void tun_cleanup(void)
 {
-       struct net_device *dev, *nxt;
+       struct tun_struct *tun, *nxt;
 
        misc_deregister(&tun_miscdev);  
 
        rtnl_lock();
-       for (dev = dev_base; dev; dev = nxt) {
-               nxt = dev->next;
-               if (dev->init == tun_net_init) 
-                       unregister_netdevice(dev);
+       list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
+               DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
+               unregister_netdevice(tun->dev);
        }
        rtnl_unlock();
        
diff -Nru a/include/linux/if_tun.h b/include/linux/if_tun.h
--- a/include/linux/if_tun.h    Fri Aug  8 11:29:09 2003
+++ b/include/linux/if_tun.h    Fri Aug  8 11:29:09 2003
@@ -32,7 +32,7 @@
 #endif
 
 struct tun_struct {
-       char                    *name;
+       struct list_head        list;
        unsigned long           flags;
        int                     attached;
        uid_t                   owner;