![zhong jiang](/assets/img/avatar_default.png)
kfree_skb has taken the null pointer into account. hence it is safe to remove the redundant null pointer check before kfree_skb. Signed-off-by: zhong jiang <zhongjiang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1384 lines
30 KiB
C
1384 lines
30 KiB
C
#include <linux/etherdevice.h>
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#include <linux/if_tap.h>
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#include <linux/if_vlan.h>
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#include <linux/interrupt.h>
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#include <linux/nsproxy.h>
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#include <linux/compat.h>
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#include <linux/if_tun.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/cache.h>
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#include <linux/sched/signal.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/wait.h>
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#include <linux/cdev.h>
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#include <linux/idr.h>
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#include <linux/fs.h>
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#include <linux/uio.h>
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#include <net/net_namespace.h>
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#include <net/rtnetlink.h>
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#include <net/sock.h>
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#include <linux/virtio_net.h>
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#include <linux/skb_array.h>
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#define TAP_IFFEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
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#define TAP_VNET_LE 0x80000000
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#define TAP_VNET_BE 0x40000000
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#ifdef CONFIG_TUN_VNET_CROSS_LE
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static inline bool tap_legacy_is_little_endian(struct tap_queue *q)
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{
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return q->flags & TAP_VNET_BE ? false :
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virtio_legacy_is_little_endian();
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}
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static long tap_get_vnet_be(struct tap_queue *q, int __user *sp)
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{
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int s = !!(q->flags & TAP_VNET_BE);
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if (put_user(s, sp))
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return -EFAULT;
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return 0;
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}
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static long tap_set_vnet_be(struct tap_queue *q, int __user *sp)
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{
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int s;
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if (get_user(s, sp))
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return -EFAULT;
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if (s)
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q->flags |= TAP_VNET_BE;
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else
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q->flags &= ~TAP_VNET_BE;
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return 0;
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}
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#else
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static inline bool tap_legacy_is_little_endian(struct tap_queue *q)
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{
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return virtio_legacy_is_little_endian();
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}
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static long tap_get_vnet_be(struct tap_queue *q, int __user *argp)
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{
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return -EINVAL;
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}
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static long tap_set_vnet_be(struct tap_queue *q, int __user *argp)
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{
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return -EINVAL;
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}
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#endif /* CONFIG_TUN_VNET_CROSS_LE */
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static inline bool tap_is_little_endian(struct tap_queue *q)
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{
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return q->flags & TAP_VNET_LE ||
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tap_legacy_is_little_endian(q);
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}
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static inline u16 tap16_to_cpu(struct tap_queue *q, __virtio16 val)
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{
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return __virtio16_to_cpu(tap_is_little_endian(q), val);
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}
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static inline __virtio16 cpu_to_tap16(struct tap_queue *q, u16 val)
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{
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return __cpu_to_virtio16(tap_is_little_endian(q), val);
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}
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static struct proto tap_proto = {
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.name = "tap",
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.owner = THIS_MODULE,
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.obj_size = sizeof(struct tap_queue),
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};
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#define TAP_NUM_DEVS (1U << MINORBITS)
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static LIST_HEAD(major_list);
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struct major_info {
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struct rcu_head rcu;
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dev_t major;
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struct idr minor_idr;
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spinlock_t minor_lock;
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const char *device_name;
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struct list_head next;
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};
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#define GOODCOPY_LEN 128
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static const struct proto_ops tap_socket_ops;
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#define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
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#define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST)
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static struct tap_dev *tap_dev_get_rcu(const struct net_device *dev)
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{
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return rcu_dereference(dev->rx_handler_data);
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}
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/*
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* RCU usage:
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* The tap_queue and the macvlan_dev are loosely coupled, the
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* pointers from one to the other can only be read while rcu_read_lock
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* or rtnl is held.
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*
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* Both the file and the macvlan_dev hold a reference on the tap_queue
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* through sock_hold(&q->sk). When the macvlan_dev goes away first,
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* q->vlan becomes inaccessible. When the files gets closed,
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* tap_get_queue() fails.
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*
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* There may still be references to the struct sock inside of the
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* queue from outbound SKBs, but these never reference back to the
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* file or the dev. The data structure is freed through __sk_free
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* when both our references and any pending SKBs are gone.
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*/
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static int tap_enable_queue(struct tap_dev *tap, struct file *file,
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struct tap_queue *q)
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{
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int err = -EINVAL;
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ASSERT_RTNL();
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if (q->enabled)
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goto out;
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err = 0;
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rcu_assign_pointer(tap->taps[tap->numvtaps], q);
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q->queue_index = tap->numvtaps;
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q->enabled = true;
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tap->numvtaps++;
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out:
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return err;
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}
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/* Requires RTNL */
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static int tap_set_queue(struct tap_dev *tap, struct file *file,
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struct tap_queue *q)
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{
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if (tap->numqueues == MAX_TAP_QUEUES)
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return -EBUSY;
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rcu_assign_pointer(q->tap, tap);
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rcu_assign_pointer(tap->taps[tap->numvtaps], q);
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sock_hold(&q->sk);
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q->file = file;
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q->queue_index = tap->numvtaps;
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q->enabled = true;
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file->private_data = q;
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list_add_tail(&q->next, &tap->queue_list);
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tap->numvtaps++;
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tap->numqueues++;
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return 0;
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}
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static int tap_disable_queue(struct tap_queue *q)
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{
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struct tap_dev *tap;
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struct tap_queue *nq;
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ASSERT_RTNL();
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if (!q->enabled)
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return -EINVAL;
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tap = rtnl_dereference(q->tap);
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if (tap) {
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int index = q->queue_index;
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BUG_ON(index >= tap->numvtaps);
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nq = rtnl_dereference(tap->taps[tap->numvtaps - 1]);
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nq->queue_index = index;
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rcu_assign_pointer(tap->taps[index], nq);
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RCU_INIT_POINTER(tap->taps[tap->numvtaps - 1], NULL);
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q->enabled = false;
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tap->numvtaps--;
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}
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return 0;
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}
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/*
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* The file owning the queue got closed, give up both
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* the reference that the files holds as well as the
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* one from the macvlan_dev if that still exists.
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*
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* Using the spinlock makes sure that we don't get
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* to the queue again after destroying it.
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*/
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static void tap_put_queue(struct tap_queue *q)
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{
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struct tap_dev *tap;
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rtnl_lock();
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tap = rtnl_dereference(q->tap);
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if (tap) {
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if (q->enabled)
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BUG_ON(tap_disable_queue(q));
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tap->numqueues--;
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RCU_INIT_POINTER(q->tap, NULL);
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sock_put(&q->sk);
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list_del_init(&q->next);
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}
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rtnl_unlock();
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synchronize_rcu();
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sock_put(&q->sk);
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}
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/*
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* Select a queue based on the rxq of the device on which this packet
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* arrived. If the incoming device is not mq, calculate a flow hash
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* to select a queue. If all fails, find the first available queue.
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* Cache vlan->numvtaps since it can become zero during the execution
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* of this function.
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*/
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static struct tap_queue *tap_get_queue(struct tap_dev *tap,
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struct sk_buff *skb)
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{
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struct tap_queue *queue = NULL;
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/* Access to taps array is protected by rcu, but access to numvtaps
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* isn't. Below we use it to lookup a queue, but treat it as a hint
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* and validate that the result isn't NULL - in case we are
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* racing against queue removal.
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*/
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int numvtaps = READ_ONCE(tap->numvtaps);
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__u32 rxq;
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if (!numvtaps)
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goto out;
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if (numvtaps == 1)
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goto single;
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/* Check if we can use flow to select a queue */
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rxq = skb_get_hash(skb);
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if (rxq) {
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queue = rcu_dereference(tap->taps[rxq % numvtaps]);
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goto out;
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}
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if (likely(skb_rx_queue_recorded(skb))) {
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rxq = skb_get_rx_queue(skb);
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while (unlikely(rxq >= numvtaps))
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rxq -= numvtaps;
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queue = rcu_dereference(tap->taps[rxq]);
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goto out;
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}
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single:
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queue = rcu_dereference(tap->taps[0]);
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out:
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return queue;
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}
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/*
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* The net_device is going away, give up the reference
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* that it holds on all queues and safely set the pointer
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* from the queues to NULL.
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*/
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void tap_del_queues(struct tap_dev *tap)
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{
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struct tap_queue *q, *tmp;
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ASSERT_RTNL();
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list_for_each_entry_safe(q, tmp, &tap->queue_list, next) {
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list_del_init(&q->next);
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RCU_INIT_POINTER(q->tap, NULL);
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if (q->enabled)
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tap->numvtaps--;
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tap->numqueues--;
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sock_put(&q->sk);
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}
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BUG_ON(tap->numvtaps);
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BUG_ON(tap->numqueues);
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/* guarantee that any future tap_set_queue will fail */
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tap->numvtaps = MAX_TAP_QUEUES;
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}
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EXPORT_SYMBOL_GPL(tap_del_queues);
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rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
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{
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struct sk_buff *skb = *pskb;
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struct net_device *dev = skb->dev;
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struct tap_dev *tap;
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struct tap_queue *q;
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netdev_features_t features = TAP_FEATURES;
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tap = tap_dev_get_rcu(dev);
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if (!tap)
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return RX_HANDLER_PASS;
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q = tap_get_queue(tap, skb);
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if (!q)
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return RX_HANDLER_PASS;
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skb_push(skb, ETH_HLEN);
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/* Apply the forward feature mask so that we perform segmentation
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* according to users wishes. This only works if VNET_HDR is
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* enabled.
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*/
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if (q->flags & IFF_VNET_HDR)
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features |= tap->tap_features;
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if (netif_needs_gso(skb, features)) {
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struct sk_buff *segs = __skb_gso_segment(skb, features, false);
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if (IS_ERR(segs))
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goto drop;
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if (!segs) {
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if (ptr_ring_produce(&q->ring, skb))
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goto drop;
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goto wake_up;
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}
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consume_skb(skb);
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while (segs) {
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struct sk_buff *nskb = segs->next;
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segs->next = NULL;
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if (ptr_ring_produce(&q->ring, segs)) {
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kfree_skb(segs);
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kfree_skb_list(nskb);
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break;
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}
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segs = nskb;
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}
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} else {
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/* If we receive a partial checksum and the tap side
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* doesn't support checksum offload, compute the checksum.
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* Note: it doesn't matter which checksum feature to
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* check, we either support them all or none.
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*/
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if (skb->ip_summed == CHECKSUM_PARTIAL &&
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!(features & NETIF_F_CSUM_MASK) &&
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skb_checksum_help(skb))
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goto drop;
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if (ptr_ring_produce(&q->ring, skb))
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goto drop;
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}
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wake_up:
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wake_up_interruptible_poll(sk_sleep(&q->sk), EPOLLIN | EPOLLRDNORM | EPOLLRDBAND);
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return RX_HANDLER_CONSUMED;
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drop:
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/* Count errors/drops only here, thus don't care about args. */
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if (tap->count_rx_dropped)
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tap->count_rx_dropped(tap);
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kfree_skb(skb);
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return RX_HANDLER_CONSUMED;
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}
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EXPORT_SYMBOL_GPL(tap_handle_frame);
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static struct major_info *tap_get_major(int major)
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{
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struct major_info *tap_major;
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list_for_each_entry_rcu(tap_major, &major_list, next) {
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if (tap_major->major == major)
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return tap_major;
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}
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return NULL;
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}
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int tap_get_minor(dev_t major, struct tap_dev *tap)
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{
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int retval = -ENOMEM;
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struct major_info *tap_major;
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rcu_read_lock();
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tap_major = tap_get_major(MAJOR(major));
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if (!tap_major) {
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retval = -EINVAL;
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goto unlock;
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}
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spin_lock(&tap_major->minor_lock);
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retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_ATOMIC);
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if (retval >= 0) {
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tap->minor = retval;
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} else if (retval == -ENOSPC) {
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netdev_err(tap->dev, "Too many tap devices\n");
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retval = -EINVAL;
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}
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spin_unlock(&tap_major->minor_lock);
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unlock:
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rcu_read_unlock();
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return retval < 0 ? retval : 0;
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}
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EXPORT_SYMBOL_GPL(tap_get_minor);
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void tap_free_minor(dev_t major, struct tap_dev *tap)
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{
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struct major_info *tap_major;
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rcu_read_lock();
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tap_major = tap_get_major(MAJOR(major));
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if (!tap_major) {
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goto unlock;
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}
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spin_lock(&tap_major->minor_lock);
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if (tap->minor) {
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idr_remove(&tap_major->minor_idr, tap->minor);
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tap->minor = 0;
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}
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spin_unlock(&tap_major->minor_lock);
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unlock:
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rcu_read_unlock();
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}
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EXPORT_SYMBOL_GPL(tap_free_minor);
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static struct tap_dev *dev_get_by_tap_file(int major, int minor)
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{
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struct net_device *dev = NULL;
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struct tap_dev *tap;
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struct major_info *tap_major;
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rcu_read_lock();
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tap_major = tap_get_major(major);
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if (!tap_major) {
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tap = NULL;
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goto unlock;
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}
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spin_lock(&tap_major->minor_lock);
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tap = idr_find(&tap_major->minor_idr, minor);
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if (tap) {
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dev = tap->dev;
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dev_hold(dev);
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}
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spin_unlock(&tap_major->minor_lock);
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unlock:
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rcu_read_unlock();
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return tap;
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}
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static void tap_sock_write_space(struct sock *sk)
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{
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wait_queue_head_t *wqueue;
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if (!sock_writeable(sk) ||
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!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
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return;
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wqueue = sk_sleep(sk);
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if (wqueue && waitqueue_active(wqueue))
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wake_up_interruptible_poll(wqueue, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
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}
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static void tap_sock_destruct(struct sock *sk)
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{
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struct tap_queue *q = container_of(sk, struct tap_queue, sk);
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ptr_ring_cleanup(&q->ring, __skb_array_destroy_skb);
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}
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static int tap_open(struct inode *inode, struct file *file)
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{
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struct net *net = current->nsproxy->net_ns;
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struct tap_dev *tap;
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struct tap_queue *q;
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int err = -ENODEV;
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rtnl_lock();
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tap = dev_get_by_tap_file(imajor(inode), iminor(inode));
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if (!tap)
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goto err;
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err = -ENOMEM;
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q = (struct tap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
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&tap_proto, 0);
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if (!q)
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goto err;
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if (ptr_ring_init(&q->ring, tap->dev->tx_queue_len, GFP_KERNEL)) {
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sk_free(&q->sk);
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goto err;
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}
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|
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RCU_INIT_POINTER(q->sock.wq, &q->wq);
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init_waitqueue_head(&q->wq.wait);
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q->sock.type = SOCK_RAW;
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q->sock.state = SS_CONNECTED;
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q->sock.file = file;
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q->sock.ops = &tap_socket_ops;
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sock_init_data(&q->sock, &q->sk);
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q->sk.sk_write_space = tap_sock_write_space;
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q->sk.sk_destruct = tap_sock_destruct;
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q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
|
|
q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
|
|
|
|
/*
|
|
* so far only KVM virtio_net uses tap, enable zero copy between
|
|
* guest kernel and host kernel when lower device supports zerocopy
|
|
*
|
|
* The macvlan supports zerocopy iff the lower device supports zero
|
|
* copy so we don't have to look at the lower device directly.
|
|
*/
|
|
if ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG))
|
|
sock_set_flag(&q->sk, SOCK_ZEROCOPY);
|
|
|
|
err = tap_set_queue(tap, file, q);
|
|
if (err) {
|
|
/* tap_sock_destruct() will take care of freeing ptr_ring */
|
|
goto err_put;
|
|
}
|
|
|
|
dev_put(tap->dev);
|
|
|
|
rtnl_unlock();
|
|
return err;
|
|
|
|
err_put:
|
|
sock_put(&q->sk);
|
|
err:
|
|
if (tap)
|
|
dev_put(tap->dev);
|
|
|
|
rtnl_unlock();
|
|
return err;
|
|
}
|
|
|
|
static int tap_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct tap_queue *q = file->private_data;
|
|
tap_put_queue(q);
|
|
return 0;
|
|
}
|
|
|
|
static __poll_t tap_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct tap_queue *q = file->private_data;
|
|
__poll_t mask = EPOLLERR;
|
|
|
|
if (!q)
|
|
goto out;
|
|
|
|
mask = 0;
|
|
poll_wait(file, &q->wq.wait, wait);
|
|
|
|
if (!ptr_ring_empty(&q->ring))
|
|
mask |= EPOLLIN | EPOLLRDNORM;
|
|
|
|
if (sock_writeable(&q->sk) ||
|
|
(!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) &&
|
|
sock_writeable(&q->sk)))
|
|
mask |= EPOLLOUT | EPOLLWRNORM;
|
|
|
|
out:
|
|
return mask;
|
|
}
|
|
|
|
static inline struct sk_buff *tap_alloc_skb(struct sock *sk, size_t prepad,
|
|
size_t len, size_t linear,
|
|
int noblock, int *err)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
/* Under a page? Don't bother with paged skb. */
|
|
if (prepad + len < PAGE_SIZE || !linear)
|
|
linear = len;
|
|
|
|
skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
|
|
err, 0);
|
|
if (!skb)
|
|
return NULL;
|
|
|
|
skb_reserve(skb, prepad);
|
|
skb_put(skb, linear);
|
|
skb->data_len = len - linear;
|
|
skb->len += len - linear;
|
|
|
|
return skb;
|
|
}
|
|
|
|
/* Neighbour code has some assumptions on HH_DATA_MOD alignment */
|
|
#define TAP_RESERVE HH_DATA_OFF(ETH_HLEN)
|
|
|
|
/* Get packet from user space buffer */
|
|
static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
|
|
struct iov_iter *from, int noblock)
|
|
{
|
|
int good_linear = SKB_MAX_HEAD(TAP_RESERVE);
|
|
struct sk_buff *skb;
|
|
struct tap_dev *tap;
|
|
unsigned long total_len = iov_iter_count(from);
|
|
unsigned long len = total_len;
|
|
int err;
|
|
struct virtio_net_hdr vnet_hdr = { 0 };
|
|
int vnet_hdr_len = 0;
|
|
int copylen = 0;
|
|
int depth;
|
|
bool zerocopy = false;
|
|
size_t linear;
|
|
|
|
if (q->flags & IFF_VNET_HDR) {
|
|
vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
|
|
|
|
err = -EINVAL;
|
|
if (len < vnet_hdr_len)
|
|
goto err;
|
|
len -= vnet_hdr_len;
|
|
|
|
err = -EFAULT;
|
|
if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from))
|
|
goto err;
|
|
iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
|
|
if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
|
|
tap16_to_cpu(q, vnet_hdr.csum_start) +
|
|
tap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
|
|
tap16_to_cpu(q, vnet_hdr.hdr_len))
|
|
vnet_hdr.hdr_len = cpu_to_tap16(q,
|
|
tap16_to_cpu(q, vnet_hdr.csum_start) +
|
|
tap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
|
|
err = -EINVAL;
|
|
if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len)
|
|
goto err;
|
|
}
|
|
|
|
err = -EINVAL;
|
|
if (unlikely(len < ETH_HLEN))
|
|
goto err;
|
|
|
|
if (msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
|
|
struct iov_iter i;
|
|
|
|
copylen = vnet_hdr.hdr_len ?
|
|
tap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
|
|
if (copylen > good_linear)
|
|
copylen = good_linear;
|
|
else if (copylen < ETH_HLEN)
|
|
copylen = ETH_HLEN;
|
|
linear = copylen;
|
|
i = *from;
|
|
iov_iter_advance(&i, copylen);
|
|
if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
|
|
zerocopy = true;
|
|
}
|
|
|
|
if (!zerocopy) {
|
|
copylen = len;
|
|
linear = tap16_to_cpu(q, vnet_hdr.hdr_len);
|
|
if (linear > good_linear)
|
|
linear = good_linear;
|
|
else if (linear < ETH_HLEN)
|
|
linear = ETH_HLEN;
|
|
}
|
|
|
|
skb = tap_alloc_skb(&q->sk, TAP_RESERVE, copylen,
|
|
linear, noblock, &err);
|
|
if (!skb)
|
|
goto err;
|
|
|
|
if (zerocopy)
|
|
err = zerocopy_sg_from_iter(skb, from);
|
|
else
|
|
err = skb_copy_datagram_from_iter(skb, 0, from, len);
|
|
|
|
if (err)
|
|
goto err_kfree;
|
|
|
|
skb_set_network_header(skb, ETH_HLEN);
|
|
skb_reset_mac_header(skb);
|
|
skb->protocol = eth_hdr(skb)->h_proto;
|
|
|
|
if (vnet_hdr_len) {
|
|
err = virtio_net_hdr_to_skb(skb, &vnet_hdr,
|
|
tap_is_little_endian(q));
|
|
if (err)
|
|
goto err_kfree;
|
|
}
|
|
|
|
skb_probe_transport_header(skb, ETH_HLEN);
|
|
|
|
/* Move network header to the right position for VLAN tagged packets */
|
|
if ((skb->protocol == htons(ETH_P_8021Q) ||
|
|
skb->protocol == htons(ETH_P_8021AD)) &&
|
|
__vlan_get_protocol(skb, skb->protocol, &depth) != 0)
|
|
skb_set_network_header(skb, depth);
|
|
|
|
rcu_read_lock();
|
|
tap = rcu_dereference(q->tap);
|
|
/* copy skb_ubuf_info for callback when skb has no error */
|
|
if (zerocopy) {
|
|
skb_shinfo(skb)->destructor_arg = msg_control;
|
|
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
|
|
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
|
|
} else if (msg_control) {
|
|
struct ubuf_info *uarg = msg_control;
|
|
uarg->callback(uarg, false);
|
|
}
|
|
|
|
if (tap) {
|
|
skb->dev = tap->dev;
|
|
dev_queue_xmit(skb);
|
|
} else {
|
|
kfree_skb(skb);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return total_len;
|
|
|
|
err_kfree:
|
|
kfree_skb(skb);
|
|
|
|
err:
|
|
rcu_read_lock();
|
|
tap = rcu_dereference(q->tap);
|
|
if (tap && tap->count_tx_dropped)
|
|
tap->count_tx_dropped(tap);
|
|
rcu_read_unlock();
|
|
|
|
return err;
|
|
}
|
|
|
|
static ssize_t tap_write_iter(struct kiocb *iocb, struct iov_iter *from)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
struct tap_queue *q = file->private_data;
|
|
|
|
return tap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
|
|
}
|
|
|
|
/* Put packet to the user space buffer */
|
|
static ssize_t tap_put_user(struct tap_queue *q,
|
|
const struct sk_buff *skb,
|
|
struct iov_iter *iter)
|
|
{
|
|
int ret;
|
|
int vnet_hdr_len = 0;
|
|
int vlan_offset = 0;
|
|
int total;
|
|
|
|
if (q->flags & IFF_VNET_HDR) {
|
|
int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;
|
|
struct virtio_net_hdr vnet_hdr;
|
|
|
|
vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
|
|
if (iov_iter_count(iter) < vnet_hdr_len)
|
|
return -EINVAL;
|
|
|
|
if (virtio_net_hdr_from_skb(skb, &vnet_hdr,
|
|
tap_is_little_endian(q), true,
|
|
vlan_hlen))
|
|
BUG();
|
|
|
|
if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
|
|
sizeof(vnet_hdr))
|
|
return -EFAULT;
|
|
|
|
iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
|
|
}
|
|
total = vnet_hdr_len;
|
|
total += skb->len;
|
|
|
|
if (skb_vlan_tag_present(skb)) {
|
|
struct {
|
|
__be16 h_vlan_proto;
|
|
__be16 h_vlan_TCI;
|
|
} veth;
|
|
veth.h_vlan_proto = skb->vlan_proto;
|
|
veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
|
|
|
|
vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
|
|
total += VLAN_HLEN;
|
|
|
|
ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
|
|
if (ret || !iov_iter_count(iter))
|
|
goto done;
|
|
|
|
ret = copy_to_iter(&veth, sizeof(veth), iter);
|
|
if (ret != sizeof(veth) || !iov_iter_count(iter))
|
|
goto done;
|
|
}
|
|
|
|
ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
|
|
skb->len - vlan_offset);
|
|
|
|
done:
|
|
return ret ? ret : total;
|
|
}
|
|
|
|
static ssize_t tap_do_read(struct tap_queue *q,
|
|
struct iov_iter *to,
|
|
int noblock, struct sk_buff *skb)
|
|
{
|
|
DEFINE_WAIT(wait);
|
|
ssize_t ret = 0;
|
|
|
|
if (!iov_iter_count(to)) {
|
|
kfree_skb(skb);
|
|
return 0;
|
|
}
|
|
|
|
if (skb)
|
|
goto put;
|
|
|
|
while (1) {
|
|
if (!noblock)
|
|
prepare_to_wait(sk_sleep(&q->sk), &wait,
|
|
TASK_INTERRUPTIBLE);
|
|
|
|
/* Read frames from the queue */
|
|
skb = ptr_ring_consume(&q->ring);
|
|
if (skb)
|
|
break;
|
|
if (noblock) {
|
|
ret = -EAGAIN;
|
|
break;
|
|
}
|
|
if (signal_pending(current)) {
|
|
ret = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
/* Nothing to read, let's sleep */
|
|
schedule();
|
|
}
|
|
if (!noblock)
|
|
finish_wait(sk_sleep(&q->sk), &wait);
|
|
|
|
put:
|
|
if (skb) {
|
|
ret = tap_put_user(q, skb, to);
|
|
if (unlikely(ret < 0))
|
|
kfree_skb(skb);
|
|
else
|
|
consume_skb(skb);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t tap_read_iter(struct kiocb *iocb, struct iov_iter *to)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
struct tap_queue *q = file->private_data;
|
|
ssize_t len = iov_iter_count(to), ret;
|
|
|
|
ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK, NULL);
|
|
ret = min_t(ssize_t, ret, len);
|
|
if (ret > 0)
|
|
iocb->ki_pos = ret;
|
|
return ret;
|
|
}
|
|
|
|
static struct tap_dev *tap_get_tap_dev(struct tap_queue *q)
|
|
{
|
|
struct tap_dev *tap;
|
|
|
|
ASSERT_RTNL();
|
|
tap = rtnl_dereference(q->tap);
|
|
if (tap)
|
|
dev_hold(tap->dev);
|
|
|
|
return tap;
|
|
}
|
|
|
|
static void tap_put_tap_dev(struct tap_dev *tap)
|
|
{
|
|
dev_put(tap->dev);
|
|
}
|
|
|
|
static int tap_ioctl_set_queue(struct file *file, unsigned int flags)
|
|
{
|
|
struct tap_queue *q = file->private_data;
|
|
struct tap_dev *tap;
|
|
int ret;
|
|
|
|
tap = tap_get_tap_dev(q);
|
|
if (!tap)
|
|
return -EINVAL;
|
|
|
|
if (flags & IFF_ATTACH_QUEUE)
|
|
ret = tap_enable_queue(tap, file, q);
|
|
else if (flags & IFF_DETACH_QUEUE)
|
|
ret = tap_disable_queue(q);
|
|
else
|
|
ret = -EINVAL;
|
|
|
|
tap_put_tap_dev(tap);
|
|
return ret;
|
|
}
|
|
|
|
static int set_offload(struct tap_queue *q, unsigned long arg)
|
|
{
|
|
struct tap_dev *tap;
|
|
netdev_features_t features;
|
|
netdev_features_t feature_mask = 0;
|
|
|
|
tap = rtnl_dereference(q->tap);
|
|
if (!tap)
|
|
return -ENOLINK;
|
|
|
|
features = tap->dev->features;
|
|
|
|
if (arg & TUN_F_CSUM) {
|
|
feature_mask = NETIF_F_HW_CSUM;
|
|
|
|
if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
|
|
if (arg & TUN_F_TSO_ECN)
|
|
feature_mask |= NETIF_F_TSO_ECN;
|
|
if (arg & TUN_F_TSO4)
|
|
feature_mask |= NETIF_F_TSO;
|
|
if (arg & TUN_F_TSO6)
|
|
feature_mask |= NETIF_F_TSO6;
|
|
}
|
|
}
|
|
|
|
/* tun/tap driver inverts the usage for TSO offloads, where
|
|
* setting the TSO bit means that the userspace wants to
|
|
* accept TSO frames and turning it off means that user space
|
|
* does not support TSO.
|
|
* For tap, we have to invert it to mean the same thing.
|
|
* When user space turns off TSO, we turn off GSO/LRO so that
|
|
* user-space will not receive TSO frames.
|
|
*/
|
|
if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6))
|
|
features |= RX_OFFLOADS;
|
|
else
|
|
features &= ~RX_OFFLOADS;
|
|
|
|
/* tap_features are the same as features on tun/tap and
|
|
* reflect user expectations.
|
|
*/
|
|
tap->tap_features = feature_mask;
|
|
if (tap->update_features)
|
|
tap->update_features(tap, features);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* provide compatibility with generic tun/tap interface
|
|
*/
|
|
static long tap_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct tap_queue *q = file->private_data;
|
|
struct tap_dev *tap;
|
|
void __user *argp = (void __user *)arg;
|
|
struct ifreq __user *ifr = argp;
|
|
unsigned int __user *up = argp;
|
|
unsigned short u;
|
|
int __user *sp = argp;
|
|
struct sockaddr sa;
|
|
int s;
|
|
int ret;
|
|
|
|
switch (cmd) {
|
|
case TUNSETIFF:
|
|
/* ignore the name, just look at flags */
|
|
if (get_user(u, &ifr->ifr_flags))
|
|
return -EFAULT;
|
|
|
|
ret = 0;
|
|
if ((u & ~TAP_IFFEATURES) != (IFF_NO_PI | IFF_TAP))
|
|
ret = -EINVAL;
|
|
else
|
|
q->flags = (q->flags & ~TAP_IFFEATURES) | u;
|
|
|
|
return ret;
|
|
|
|
case TUNGETIFF:
|
|
rtnl_lock();
|
|
tap = tap_get_tap_dev(q);
|
|
if (!tap) {
|
|
rtnl_unlock();
|
|
return -ENOLINK;
|
|
}
|
|
|
|
ret = 0;
|
|
u = q->flags;
|
|
if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) ||
|
|
put_user(u, &ifr->ifr_flags))
|
|
ret = -EFAULT;
|
|
tap_put_tap_dev(tap);
|
|
rtnl_unlock();
|
|
return ret;
|
|
|
|
case TUNSETQUEUE:
|
|
if (get_user(u, &ifr->ifr_flags))
|
|
return -EFAULT;
|
|
rtnl_lock();
|
|
ret = tap_ioctl_set_queue(file, u);
|
|
rtnl_unlock();
|
|
return ret;
|
|
|
|
case TUNGETFEATURES:
|
|
if (put_user(IFF_TAP | IFF_NO_PI | TAP_IFFEATURES, up))
|
|
return -EFAULT;
|
|
return 0;
|
|
|
|
case TUNSETSNDBUF:
|
|
if (get_user(s, sp))
|
|
return -EFAULT;
|
|
if (s <= 0)
|
|
return -EINVAL;
|
|
|
|
q->sk.sk_sndbuf = s;
|
|
return 0;
|
|
|
|
case TUNGETVNETHDRSZ:
|
|
s = q->vnet_hdr_sz;
|
|
if (put_user(s, sp))
|
|
return -EFAULT;
|
|
return 0;
|
|
|
|
case TUNSETVNETHDRSZ:
|
|
if (get_user(s, sp))
|
|
return -EFAULT;
|
|
if (s < (int)sizeof(struct virtio_net_hdr))
|
|
return -EINVAL;
|
|
|
|
q->vnet_hdr_sz = s;
|
|
return 0;
|
|
|
|
case TUNGETVNETLE:
|
|
s = !!(q->flags & TAP_VNET_LE);
|
|
if (put_user(s, sp))
|
|
return -EFAULT;
|
|
return 0;
|
|
|
|
case TUNSETVNETLE:
|
|
if (get_user(s, sp))
|
|
return -EFAULT;
|
|
if (s)
|
|
q->flags |= TAP_VNET_LE;
|
|
else
|
|
q->flags &= ~TAP_VNET_LE;
|
|
return 0;
|
|
|
|
case TUNGETVNETBE:
|
|
return tap_get_vnet_be(q, sp);
|
|
|
|
case TUNSETVNETBE:
|
|
return tap_set_vnet_be(q, sp);
|
|
|
|
case TUNSETOFFLOAD:
|
|
/* let the user check for future flags */
|
|
if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
|
|
TUN_F_TSO_ECN | TUN_F_UFO))
|
|
return -EINVAL;
|
|
|
|
rtnl_lock();
|
|
ret = set_offload(q, arg);
|
|
rtnl_unlock();
|
|
return ret;
|
|
|
|
case SIOCGIFHWADDR:
|
|
rtnl_lock();
|
|
tap = tap_get_tap_dev(q);
|
|
if (!tap) {
|
|
rtnl_unlock();
|
|
return -ENOLINK;
|
|
}
|
|
ret = 0;
|
|
u = tap->dev->type;
|
|
if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) ||
|
|
copy_to_user(&ifr->ifr_hwaddr.sa_data, tap->dev->dev_addr, ETH_ALEN) ||
|
|
put_user(u, &ifr->ifr_hwaddr.sa_family))
|
|
ret = -EFAULT;
|
|
tap_put_tap_dev(tap);
|
|
rtnl_unlock();
|
|
return ret;
|
|
|
|
case SIOCSIFHWADDR:
|
|
if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
|
|
return -EFAULT;
|
|
rtnl_lock();
|
|
tap = tap_get_tap_dev(q);
|
|
if (!tap) {
|
|
rtnl_unlock();
|
|
return -ENOLINK;
|
|
}
|
|
ret = dev_set_mac_address(tap->dev, &sa);
|
|
tap_put_tap_dev(tap);
|
|
rtnl_unlock();
|
|
return ret;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
static long tap_compat_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
return tap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
|
|
}
|
|
#endif
|
|
|
|
static const struct file_operations tap_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = tap_open,
|
|
.release = tap_release,
|
|
.read_iter = tap_read_iter,
|
|
.write_iter = tap_write_iter,
|
|
.poll = tap_poll,
|
|
.llseek = no_llseek,
|
|
.unlocked_ioctl = tap_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = tap_compat_ioctl,
|
|
#endif
|
|
};
|
|
|
|
static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp)
|
|
{
|
|
struct tun_xdp_hdr *hdr = xdp->data_hard_start;
|
|
struct virtio_net_hdr *gso = &hdr->gso;
|
|
int buflen = hdr->buflen;
|
|
int vnet_hdr_len = 0;
|
|
struct tap_dev *tap;
|
|
struct sk_buff *skb;
|
|
int err, depth;
|
|
|
|
if (q->flags & IFF_VNET_HDR)
|
|
vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
|
|
|
|
skb = build_skb(xdp->data_hard_start, buflen);
|
|
if (!skb) {
|
|
err = -ENOMEM;
|
|
goto err;
|
|
}
|
|
|
|
skb_reserve(skb, xdp->data - xdp->data_hard_start);
|
|
skb_put(skb, xdp->data_end - xdp->data);
|
|
|
|
skb_set_network_header(skb, ETH_HLEN);
|
|
skb_reset_mac_header(skb);
|
|
skb->protocol = eth_hdr(skb)->h_proto;
|
|
|
|
if (vnet_hdr_len) {
|
|
err = virtio_net_hdr_to_skb(skb, gso, tap_is_little_endian(q));
|
|
if (err)
|
|
goto err_kfree;
|
|
}
|
|
|
|
skb_probe_transport_header(skb, ETH_HLEN);
|
|
|
|
/* Move network header to the right position for VLAN tagged packets */
|
|
if ((skb->protocol == htons(ETH_P_8021Q) ||
|
|
skb->protocol == htons(ETH_P_8021AD)) &&
|
|
__vlan_get_protocol(skb, skb->protocol, &depth) != 0)
|
|
skb_set_network_header(skb, depth);
|
|
|
|
rcu_read_lock();
|
|
tap = rcu_dereference(q->tap);
|
|
if (tap) {
|
|
skb->dev = tap->dev;
|
|
dev_queue_xmit(skb);
|
|
} else {
|
|
kfree_skb(skb);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return 0;
|
|
|
|
err_kfree:
|
|
kfree_skb(skb);
|
|
err:
|
|
rcu_read_lock();
|
|
tap = rcu_dereference(q->tap);
|
|
if (tap && tap->count_tx_dropped)
|
|
tap->count_tx_dropped(tap);
|
|
rcu_read_unlock();
|
|
return err;
|
|
}
|
|
|
|
static int tap_sendmsg(struct socket *sock, struct msghdr *m,
|
|
size_t total_len)
|
|
{
|
|
struct tap_queue *q = container_of(sock, struct tap_queue, sock);
|
|
struct tun_msg_ctl *ctl = m->msg_control;
|
|
struct xdp_buff *xdp;
|
|
int i;
|
|
|
|
if (ctl && (ctl->type == TUN_MSG_PTR)) {
|
|
for (i = 0; i < ctl->num; i++) {
|
|
xdp = &((struct xdp_buff *)ctl->ptr)[i];
|
|
tap_get_user_xdp(q, xdp);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
return tap_get_user(q, ctl ? ctl->ptr : NULL, &m->msg_iter,
|
|
m->msg_flags & MSG_DONTWAIT);
|
|
}
|
|
|
|
static int tap_recvmsg(struct socket *sock, struct msghdr *m,
|
|
size_t total_len, int flags)
|
|
{
|
|
struct tap_queue *q = container_of(sock, struct tap_queue, sock);
|
|
struct sk_buff *skb = m->msg_control;
|
|
int ret;
|
|
if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) {
|
|
kfree_skb(skb);
|
|
return -EINVAL;
|
|
}
|
|
ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, skb);
|
|
if (ret > total_len) {
|
|
m->msg_flags |= MSG_TRUNC;
|
|
ret = flags & MSG_TRUNC ? ret : total_len;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int tap_peek_len(struct socket *sock)
|
|
{
|
|
struct tap_queue *q = container_of(sock, struct tap_queue,
|
|
sock);
|
|
return PTR_RING_PEEK_CALL(&q->ring, __skb_array_len_with_tag);
|
|
}
|
|
|
|
/* Ops structure to mimic raw sockets with tun */
|
|
static const struct proto_ops tap_socket_ops = {
|
|
.sendmsg = tap_sendmsg,
|
|
.recvmsg = tap_recvmsg,
|
|
.peek_len = tap_peek_len,
|
|
};
|
|
|
|
/* Get an underlying socket object from tun file. Returns error unless file is
|
|
* attached to a device. The returned object works like a packet socket, it
|
|
* can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
|
|
* holding a reference to the file for as long as the socket is in use. */
|
|
struct socket *tap_get_socket(struct file *file)
|
|
{
|
|
struct tap_queue *q;
|
|
if (file->f_op != &tap_fops)
|
|
return ERR_PTR(-EINVAL);
|
|
q = file->private_data;
|
|
if (!q)
|
|
return ERR_PTR(-EBADFD);
|
|
return &q->sock;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tap_get_socket);
|
|
|
|
struct ptr_ring *tap_get_ptr_ring(struct file *file)
|
|
{
|
|
struct tap_queue *q;
|
|
|
|
if (file->f_op != &tap_fops)
|
|
return ERR_PTR(-EINVAL);
|
|
q = file->private_data;
|
|
if (!q)
|
|
return ERR_PTR(-EBADFD);
|
|
return &q->ring;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tap_get_ptr_ring);
|
|
|
|
int tap_queue_resize(struct tap_dev *tap)
|
|
{
|
|
struct net_device *dev = tap->dev;
|
|
struct tap_queue *q;
|
|
struct ptr_ring **rings;
|
|
int n = tap->numqueues;
|
|
int ret, i = 0;
|
|
|
|
rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
|
|
if (!rings)
|
|
return -ENOMEM;
|
|
|
|
list_for_each_entry(q, &tap->queue_list, next)
|
|
rings[i++] = &q->ring;
|
|
|
|
ret = ptr_ring_resize_multiple(rings, n,
|
|
dev->tx_queue_len, GFP_KERNEL,
|
|
__skb_array_destroy_skb);
|
|
|
|
kfree(rings);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tap_queue_resize);
|
|
|
|
static int tap_list_add(dev_t major, const char *device_name)
|
|
{
|
|
struct major_info *tap_major;
|
|
|
|
tap_major = kzalloc(sizeof(*tap_major), GFP_ATOMIC);
|
|
if (!tap_major)
|
|
return -ENOMEM;
|
|
|
|
tap_major->major = MAJOR(major);
|
|
|
|
idr_init(&tap_major->minor_idr);
|
|
spin_lock_init(&tap_major->minor_lock);
|
|
|
|
tap_major->device_name = device_name;
|
|
|
|
list_add_tail_rcu(&tap_major->next, &major_list);
|
|
return 0;
|
|
}
|
|
|
|
int tap_create_cdev(struct cdev *tap_cdev, dev_t *tap_major,
|
|
const char *device_name, struct module *module)
|
|
{
|
|
int err;
|
|
|
|
err = alloc_chrdev_region(tap_major, 0, TAP_NUM_DEVS, device_name);
|
|
if (err)
|
|
goto out1;
|
|
|
|
cdev_init(tap_cdev, &tap_fops);
|
|
tap_cdev->owner = module;
|
|
err = cdev_add(tap_cdev, *tap_major, TAP_NUM_DEVS);
|
|
if (err)
|
|
goto out2;
|
|
|
|
err = tap_list_add(*tap_major, device_name);
|
|
if (err)
|
|
goto out3;
|
|
|
|
return 0;
|
|
|
|
out3:
|
|
cdev_del(tap_cdev);
|
|
out2:
|
|
unregister_chrdev_region(*tap_major, TAP_NUM_DEVS);
|
|
out1:
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tap_create_cdev);
|
|
|
|
void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev)
|
|
{
|
|
struct major_info *tap_major, *tmp;
|
|
|
|
cdev_del(tap_cdev);
|
|
unregister_chrdev_region(major, TAP_NUM_DEVS);
|
|
list_for_each_entry_safe(tap_major, tmp, &major_list, next) {
|
|
if (tap_major->major == MAJOR(major)) {
|
|
idr_destroy(&tap_major->minor_idr);
|
|
list_del_rcu(&tap_major->next);
|
|
kfree_rcu(tap_major, rcu);
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(tap_destroy_cdev);
|
|
|
|
MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
|
|
MODULE_AUTHOR("Sainath Grandhi <sainath.grandhi@intel.com>");
|
|
MODULE_LICENSE("GPL");
|