tun: Limit amount of queued packets per device
[safe/jmp/linux-2.6] / drivers / net / tun.c
index 15d6763..0476549 100644 (file)
@@ -64,6 +64,7 @@
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
 #include <net/rtnetlink.h>
+#include <net/sock.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -95,6 +96,8 @@ struct tun_file {
        wait_queue_head_t       read_wait;
 };
 
+struct tun_sock;
+
 struct tun_struct {
        struct tun_file         *tfile;
        unsigned int            flags;
@@ -107,12 +110,24 @@ struct tun_struct {
        struct fasync_struct    *fasync;
 
        struct tap_filter       txflt;
+       struct sock             *sk;
+       struct socket           socket;
 
 #ifdef TUN_DEBUG
        int debug;
 #endif
 };
 
+struct tun_sock {
+       struct sock             sk;
+       struct tun_struct       *tun;
+};
+
+static inline struct tun_sock *tun_sk(struct sock *sk)
+{
+       return container_of(sk, struct tun_sock, sk);
+}
+
 static int tun_attach(struct tun_struct *tun, struct file *file)
 {
        struct tun_file *tfile = file->private_data;
@@ -461,7 +476,8 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 {
        struct tun_file *tfile = file->private_data;
        struct tun_struct *tun = __tun_get(tfile);
-       unsigned int mask = POLLOUT | POLLWRNORM;
+       struct sock *sk = tun->sk;
+       unsigned int mask = 0;
 
        if (!tun)
                return POLLERR;
@@ -473,6 +489,11 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
        if (!skb_queue_empty(&tun->readq))
                mask |= POLLIN | POLLRDNORM;
 
+       if (sock_writeable(sk) ||
+           (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
+            sock_writeable(sk)))
+               mask |= POLLOUT | POLLWRNORM;
+
        if (tun->dev->reg_state != NETREG_REGISTERED)
                mask = POLLERR;
 
@@ -482,66 +503,35 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 
 /* prepad is the amount to reserve at front.  len is length after that.
  * linear is a hint as to how much to copy (usually headers). */
-static struct sk_buff *tun_alloc_skb(size_t prepad, size_t len, size_t linear,
-                                    gfp_t gfp)
+static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
+                                           size_t prepad, size_t len,
+                                           size_t linear, int noblock)
 {
+       struct sock *sk = tun->sk;
        struct sk_buff *skb;
-       unsigned int i;
-
-       skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN);
-       if (skb) {
-               skb_reserve(skb, prepad);
-               skb_put(skb, len);
-               return skb;
-       }
+       int err;
 
        /* Under a page?  Don't bother with paged skb. */
        if (prepad + len < PAGE_SIZE)
-               return NULL;
+               linear = len;
 
-       /* Start with a normal skb, and add pages. */
-       skb = alloc_skb(prepad + linear, gfp);
+       skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
+                                  &err);
        if (!skb)
-               return NULL;
+               return ERR_PTR(err);
 
        skb_reserve(skb, prepad);
        skb_put(skb, linear);
-
-       len -= linear;
-
-       for (i = 0; i < MAX_SKB_FRAGS; i++) {
-               skb_frag_t *f = &skb_shinfo(skb)->frags[i];
-
-               f->page = alloc_page(gfp|__GFP_ZERO);
-               if (!f->page)
-                       break;
-
-               f->page_offset = 0;
-               f->size = PAGE_SIZE;
-
-               skb->data_len += PAGE_SIZE;
-               skb->len += PAGE_SIZE;
-               skb->truesize += PAGE_SIZE;
-               skb_shinfo(skb)->nr_frags++;
-
-               if (len < PAGE_SIZE) {
-                       len = 0;
-                       break;
-               }
-               len -= PAGE_SIZE;
-       }
-
-       /* Too large, or alloc fail? */
-       if (unlikely(len)) {
-               kfree_skb(skb);
-               skb = NULL;
-       }
+       skb->data_len = len - linear;
+       skb->len += len - linear;
 
        return skb;
 }
 
 /* Get packet from user space buffer */
-static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
+static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
+                                      struct iovec *iv, size_t count,
+                                      int noblock)
 {
        struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
        struct sk_buff *skb;
@@ -573,9 +563,11 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
                        return -EINVAL;
        }
 
-       if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) {
-               tun->dev->stats.rx_dropped++;
-               return -ENOMEM;
+       skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
+       if (IS_ERR(skb)) {
+               if (PTR_ERR(skb) != -EAGAIN)
+                       tun->dev->stats.rx_dropped++;
+               return PTR_ERR(skb);
        }
 
        if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
@@ -661,7 +653,8 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
                              unsigned long count, loff_t pos)
 {
-       struct tun_struct *tun = tun_get(iocb->ki_filp);
+       struct file *file = iocb->ki_filp;
+       struct tun_struct *tun = file->private_data;
        ssize_t result;
 
        if (!tun)
@@ -669,7 +662,8 @@ static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 
        DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 
-       result = tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
+       result = tun_get_user(tun, (struct iovec *)iv, iov_length(iv, count),
+                             file->f_flags & O_NONBLOCK);
 
        tun_put(tun);
        return result;
@@ -828,11 +822,40 @@ static struct rtnl_link_ops tun_link_ops __read_mostly = {
        .validate       = tun_validate,
 };
 
+static void tun_sock_write_space(struct sock *sk)
+{
+       struct tun_struct *tun;
+
+       if (!sock_writeable(sk))
+               return;
+
+       if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
+               wake_up_interruptible_sync(sk->sk_sleep);
+
+       if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
+               return;
+
+       tun = container_of(sk, struct tun_sock, sk)->tun;
+       kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
+}
+
+static void tun_sock_destruct(struct sock *sk)
+{
+       dev_put(container_of(sk, struct tun_sock, sk)->tun->dev);
+}
+
+static struct proto tun_proto = {
+       .name           = "tun",
+       .owner          = THIS_MODULE,
+       .obj_size       = sizeof(struct tun_sock),
+};
 
 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 {
+       struct sock *sk;
        struct tun_struct *tun;
        struct net_device *dev;
+       struct tun_file *tfile = file->private_data;
        int err;
 
        dev = __dev_get_by_name(net, ifr->ifr_name);
@@ -885,14 +908,31 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                tun->flags = flags;
                tun->txflt.count = 0;
 
+               err = -ENOMEM;
+               sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
+               if (!sk)
+                       goto err_free_dev;
+
+               /* This ref count is for tun->sk. */
+               dev_hold(dev);
+               sock_init_data(&tun->socket, sk);
+               sk->sk_write_space = tun_sock_write_space;
+               sk->sk_destruct = tun_sock_destruct;
+               sk->sk_sndbuf = INT_MAX;
+               sk->sk_sleep = &tfile->read_wait;
+
+               tun->sk = sk;
+               container_of(sk, struct tun_sock, sk)->tun = tun;
+
                tun_net_init(dev);
 
                if (strchr(dev->name, '%')) {
                        err = dev_alloc_name(dev, dev->name);
                        if (err < 0)
-                               goto err_free_dev;
+                               goto err_free_sk;
                }
 
+               err = -EINVAL;
                err = register_netdevice(tun->dev);
                if (err < 0)
                        goto err_free_dev;
@@ -928,6 +968,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
        strcpy(ifr->ifr_name, tun->dev->name);
        return 0;
 
+ err_free_sk:
+       sock_put(sk);
  err_free_dev:
        free_netdev(dev);
  failed:
@@ -1012,6 +1054,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
        struct tun_struct *tun;
        void __user* argp = (void __user*)arg;
        struct ifreq ifr;
+       int sndbuf;
        int ret;
 
        if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
@@ -1151,6 +1194,22 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
                rtnl_unlock();
                break;
+
+       case TUNGETSNDBUF:
+               sndbuf = tun->sk->sk_sndbuf;
+               if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
+                       ret = -EFAULT;
+               break;
+
+       case TUNSETSNDBUF:
+               if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
+                       ret = -EFAULT;
+                       break;
+               }
+
+               tun->sk->sk_sndbuf = sndbuf;
+               break;
+
        default:
                ret = -EINVAL;
                break;
@@ -1218,8 +1277,10 @@ static int tun_chr_close(struct inode *inode, struct file *file)
                __tun_detach(tun);
 
                /* If desireable, unregister the netdevice. */
-               if (!(tun->flags & TUN_PERSIST))
+               if (!(tun->flags & TUN_PERSIST)) {
+                       sock_put(tun->sk);
                        unregister_netdevice(tun->dev);
+               }
 
                rtnl_unlock();
        }