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macvtap.c
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#include <linux/etherdevice.h>
#include <linux/if_macvlan.h>
#include <linux/if_vlan.h>
#include <linux/interrupt.h>
#include <linux/nsproxy.h>
#include <linux/compat.h>
#include <linux/if_tun.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/cache.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/cdev.h>
#include <linux/idr.h>
#include <linux/fs.h>
#include <linux/uio.h>
#include <net/net_namespace.h>
#include <net/rtnetlink.h>
#include <net/sock.h>
#include <linux/virtio_net.h>
/*
* A macvtap queue is the central object of this driver, it connects
* an open character device to a macvlan interface. There can be
* multiple queues on one interface, which map back to queues
* implemented in hardware on the underlying device.
*
* macvtap_proto is used to allocate queues through the sock allocation
* mechanism.
*
*/
struct macvtap_queue {
struct sock sk;
struct socket sock;
struct socket_wq wq;
int vnet_hdr_sz;
struct macvlan_dev __rcu *vlan;
struct file *file;
unsigned int flags;
u16 queue_index;
bool enabled;
struct list_head next;
};
#define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
#define MACVTAP_VNET_LE 0x80000000
static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val)
{
return __virtio16_to_cpu(q->flags & MACVTAP_VNET_LE, val);
}
static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val)
{
return __cpu_to_virtio16(q->flags & MACVTAP_VNET_LE, val);
}
static struct proto macvtap_proto = {
.name = "macvtap",
.owner = THIS_MODULE,
.obj_size = sizeof (struct macvtap_queue),
};
/*
* Variables for dealing with macvtaps device numbers.
*/
static dev_t macvtap_major;
#define MACVTAP_NUM_DEVS (1U << MINORBITS)
static DEFINE_MUTEX(minor_lock);
static DEFINE_IDR(minor_idr);
#define GOODCOPY_LEN 128
static struct class *macvtap_class;
static struct cdev macvtap_cdev;
static const struct proto_ops macvtap_socket_ops;
#define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
NETIF_F_TSO6 | NETIF_F_UFO)
#define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
#define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG)
static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev)
{
return rcu_dereference(dev->rx_handler_data);
}
/*
* RCU usage:
* The macvtap_queue and the macvlan_dev are loosely coupled, the
* pointers from one to the other can only be read while rcu_read_lock
* or rtnl is held.
*
* Both the file and the macvlan_dev hold a reference on the macvtap_queue
* through sock_hold(&q->sk). When the macvlan_dev goes away first,
* q->vlan becomes inaccessible. When the files gets closed,
* macvtap_get_queue() fails.
*
* There may still be references to the struct sock inside of the
* queue from outbound SKBs, but these never reference back to the
* file or the dev. The data structure is freed through __sk_free
* when both our references and any pending SKBs are gone.
*/
static int macvtap_enable_queue(struct net_device *dev, struct file *file,
struct macvtap_queue *q)
{
struct macvlan_dev *vlan = netdev_priv(dev);
int err = -EINVAL;
ASSERT_RTNL();
if (q->enabled)
goto out;
err = 0;
rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
q->queue_index = vlan->numvtaps;
q->enabled = true;
vlan->numvtaps++;
out:
return err;
}
/* Requires RTNL */
static int macvtap_set_queue(struct net_device *dev, struct file *file,
struct macvtap_queue *q)
{
struct macvlan_dev *vlan = netdev_priv(dev);
if (vlan->numqueues == MAX_MACVTAP_QUEUES)
return -EBUSY;
rcu_assign_pointer(q->vlan, vlan);
rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
sock_hold(&q->sk);
q->file = file;
q->queue_index = vlan->numvtaps;
q->enabled = true;
file->private_data = q;
list_add_tail(&q->next, &vlan->queue_list);
vlan->numvtaps++;
vlan->numqueues++;
return 0;
}
static int macvtap_disable_queue(struct macvtap_queue *q)
{
struct macvlan_dev *vlan;
struct macvtap_queue *nq;
ASSERT_RTNL();
if (!q->enabled)
return -EINVAL;
vlan = rtnl_dereference(q->vlan);
if (vlan) {
int index = q->queue_index;
BUG_ON(index >= vlan->numvtaps);
nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]);
nq->queue_index = index;
rcu_assign_pointer(vlan->taps[index], nq);
RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL);
q->enabled = false;
vlan->numvtaps--;
}
return 0;
}
/*
* The file owning the queue got closed, give up both
* the reference that the files holds as well as the
* one from the macvlan_dev if that still exists.
*
* Using the spinlock makes sure that we don't get
* to the queue again after destroying it.
*/
static void macvtap_put_queue(struct macvtap_queue *q)
{
struct macvlan_dev *vlan;
rtnl_lock();
vlan = rtnl_dereference(q->vlan);
if (vlan) {
if (q->enabled)
BUG_ON(macvtap_disable_queue(q));
vlan->numqueues--;
RCU_INIT_POINTER(q->vlan, NULL);
sock_put(&q->sk);
list_del_init(&q->next);
}
rtnl_unlock();
synchronize_rcu();
sock_put(&q->sk);
}
/*
* Select a queue based on the rxq of the device on which this packet
* arrived. If the incoming device is not mq, calculate a flow hash
* to select a queue. If all fails, find the first available queue.
* Cache vlan->numvtaps since it can become zero during the execution
* of this function.
*/
static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
struct sk_buff *skb)
{
struct macvlan_dev *vlan = netdev_priv(dev);
struct macvtap_queue *tap = NULL;
/* Access to taps array is protected by rcu, but access to numvtaps
* isn't. Below we use it to lookup a queue, but treat it as a hint
* and validate that the result isn't NULL - in case we are
* racing against queue removal.
*/
int numvtaps = ACCESS_ONCE(vlan->numvtaps);
__u32 rxq;
if (!numvtaps)
goto out;
/* Check if we can use flow to select a queue */
rxq = skb_get_hash(skb);
if (rxq) {
tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
goto out;
}
if (likely(skb_rx_queue_recorded(skb))) {
rxq = skb_get_rx_queue(skb);
while (unlikely(rxq >= numvtaps))
rxq -= numvtaps;
tap = rcu_dereference(vlan->taps[rxq]);
goto out;
}
tap = rcu_dereference(vlan->taps[0]);
out:
return tap;
}
/*
* The net_device is going away, give up the reference
* that it holds on all queues and safely set the pointer
* from the queues to NULL.
*/
static void macvtap_del_queues(struct net_device *dev)
{
struct macvlan_dev *vlan = netdev_priv(dev);
struct macvtap_queue *q, *tmp, *qlist[MAX_MACVTAP_QUEUES];
int i, j = 0;
ASSERT_RTNL();
list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) {
list_del_init(&q->next);
qlist[j++] = q;
RCU_INIT_POINTER(q->vlan, NULL);
if (q->enabled)
vlan->numvtaps--;
vlan->numqueues--;
}
for (i = 0; i < vlan->numvtaps; i++)
RCU_INIT_POINTER(vlan->taps[i], NULL);
BUG_ON(vlan->numvtaps);
BUG_ON(vlan->numqueues);
/* guarantee that any future macvtap_set_queue will fail */
vlan->numvtaps = MAX_MACVTAP_QUEUES;
for (--j; j >= 0; j--)
sock_put(&qlist[j]->sk);
}
static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
{
struct sk_buff *skb = *pskb;
struct net_device *dev = skb->dev;
struct macvlan_dev *vlan;
struct macvtap_queue *q;
netdev_features_t features = TAP_FEATURES;
vlan = macvtap_get_vlan_rcu(dev);
if (!vlan)
return RX_HANDLER_PASS;
q = macvtap_get_queue(dev, skb);
if (!q)
return RX_HANDLER_PASS;
if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
goto drop;
skb_push(skb, ETH_HLEN);
/* Apply the forward feature mask so that we perform segmentation
* according to users wishes. This only works if VNET_HDR is
* enabled.
*/
if (q->flags & IFF_VNET_HDR)
features |= vlan->tap_features;
if (netif_needs_gso(dev, skb, features)) {
struct sk_buff *segs = __skb_gso_segment(skb, features, false);
if (IS_ERR(segs))
goto drop;
if (!segs) {
skb_queue_tail(&q->sk.sk_receive_queue, skb);
goto wake_up;
}
kfree_skb(skb);
while (segs) {
struct sk_buff *nskb = segs->next;
segs->next = NULL;
skb_queue_tail(&q->sk.sk_receive_queue, segs);
segs = nskb;
}
} else {
/* If we receive a partial checksum and the tap side
* doesn't support checksum offload, compute the checksum.
* Note: it doesn't matter which checksum feature to
* check, we either support them all or none.
*/
if (skb->ip_summed == CHECKSUM_PARTIAL &&
!(features & NETIF_F_ALL_CSUM) &&
skb_checksum_help(skb))
goto drop;
skb_queue_tail(&q->sk.sk_receive_queue, skb);
}
wake_up:
wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
return RX_HANDLER_CONSUMED;
drop:
/* Count errors/drops only here, thus don't care about args. */
macvlan_count_rx(vlan, 0, 0, 0);
kfree_skb(skb);
return RX_HANDLER_CONSUMED;
}
static int macvtap_get_minor(struct macvlan_dev *vlan)
{
int retval = -ENOMEM;
mutex_lock(&minor_lock);
retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL);
if (retval >= 0) {
vlan->minor = retval;
} else if (retval == -ENOSPC) {
printk(KERN_ERR "too many macvtap devices\n");
retval = -EINVAL;
}
mutex_unlock(&minor_lock);
return retval < 0 ? retval : 0;
}
static void macvtap_free_minor(struct macvlan_dev *vlan)
{
mutex_lock(&minor_lock);
if (vlan->minor) {
idr_remove(&minor_idr, vlan->minor);
vlan->minor = 0;
}
mutex_unlock(&minor_lock);
}
static struct net_device *dev_get_by_macvtap_minor(int minor)
{
struct net_device *dev = NULL;
struct macvlan_dev *vlan;
mutex_lock(&minor_lock);
vlan = idr_find(&minor_idr, minor);
if (vlan) {
dev = vlan->dev;
dev_hold(dev);
}
mutex_unlock(&minor_lock);
return dev;
}
static int macvtap_newlink(struct net *src_net,
struct net_device *dev,
struct nlattr *tb[],
struct nlattr *data[])
{
struct macvlan_dev *vlan = netdev_priv(dev);
int err;
INIT_LIST_HEAD(&vlan->queue_list);
/* Since macvlan supports all offloads by default, make
* tap support all offloads also.
*/
vlan->tap_features = TUN_OFFLOADS;
err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan);
if (err)
return err;
/* Don't put anything that may fail after macvlan_common_newlink
* because we can't undo what it does.
*/
return macvlan_common_newlink(src_net, dev, tb, data);
}
static void macvtap_dellink(struct net_device *dev,
struct list_head *head)
{
netdev_rx_handler_unregister(dev);
macvtap_del_queues(dev);
macvlan_dellink(dev, head);
}
static void macvtap_setup(struct net_device *dev)
{
macvlan_common_setup(dev);
dev->tx_queue_len = TUN_READQ_SIZE;
}
static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
.kind = "macvtap",
.setup = macvtap_setup,
.newlink = macvtap_newlink,
.dellink = macvtap_dellink,
};
static void macvtap_sock_write_space(struct sock *sk)
{
wait_queue_head_t *wqueue;
if (!sock_writeable(sk) ||
!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
return;
wqueue = sk_sleep(sk);
if (wqueue && waitqueue_active(wqueue))
wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
}
static void macvtap_sock_destruct(struct sock *sk)
{
skb_queue_purge(&sk->sk_receive_queue);
}
static int macvtap_open(struct inode *inode, struct file *file)
{
struct net *net = current->nsproxy->net_ns;
struct net_device *dev;
struct macvtap_queue *q;
int err = -ENODEV;
rtnl_lock();
dev = dev_get_by_macvtap_minor(iminor(inode));
if (!dev)
goto out;
err = -ENOMEM;
q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
&macvtap_proto);
if (!q)
goto out;
RCU_INIT_POINTER(q->sock.wq, &q->wq);
init_waitqueue_head(&q->wq.wait);
q->sock.type = SOCK_RAW;
q->sock.state = SS_CONNECTED;
q->sock.file = file;
q->sock.ops = &macvtap_socket_ops;
sock_init_data(&q->sock, &q->sk);
q->sk.sk_write_space = macvtap_sock_write_space;
q->sk.sk_destruct = macvtap_sock_destruct;
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 macvtap, 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 ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
sock_set_flag(&q->sk, SOCK_ZEROCOPY);
err = macvtap_set_queue(dev, file, q);
if (err)
sock_put(&q->sk);
out:
if (dev)
dev_put(dev);
rtnl_unlock();
return err;
}
static int macvtap_release(struct inode *inode, struct file *file)
{
struct macvtap_queue *q = file->private_data;
macvtap_put_queue(q);
return 0;
}
static unsigned int macvtap_poll(struct file *file, poll_table * wait)
{
struct macvtap_queue *q = file->private_data;
unsigned int mask = POLLERR;
if (!q)
goto out;
mask = 0;
poll_wait(file, &q->wq.wait, wait);
if (!skb_queue_empty(&q->sk.sk_receive_queue))
mask |= POLLIN | POLLRDNORM;
if (sock_writeable(&q->sk) ||
(!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
sock_writeable(&q->sk)))
mask |= POLLOUT | POLLWRNORM;
out:
return mask;
}
static inline struct sk_buff *macvtap_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;
}
/*
* macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
* be shared with the tun/tap driver.
*/
static int macvtap_skb_from_vnet_hdr(struct macvtap_queue *q,
struct sk_buff *skb,
struct virtio_net_hdr *vnet_hdr)
{
unsigned short gso_type = 0;
if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
case VIRTIO_NET_HDR_GSO_TCPV4:
gso_type = SKB_GSO_TCPV4;
break;
case VIRTIO_NET_HDR_GSO_TCPV6:
gso_type = SKB_GSO_TCPV6;
break;
case VIRTIO_NET_HDR_GSO_UDP:
gso_type = SKB_GSO_UDP;
break;
default:
return -EINVAL;
}
if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
gso_type |= SKB_GSO_TCP_ECN;
if (vnet_hdr->gso_size == 0)
return -EINVAL;
}
if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
if (!skb_partial_csum_set(skb, macvtap16_to_cpu(q, vnet_hdr->csum_start),
macvtap16_to_cpu(q, vnet_hdr->csum_offset)))
return -EINVAL;
}
if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
skb_shinfo(skb)->gso_size = macvtap16_to_cpu(q, vnet_hdr->gso_size);
skb_shinfo(skb)->gso_type = gso_type;
/* Header must be checked, and gso_segs computed. */
skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
skb_shinfo(skb)->gso_segs = 0;
}
return 0;
}
static void macvtap_skb_to_vnet_hdr(struct macvtap_queue *q,
const struct sk_buff *skb,
struct virtio_net_hdr *vnet_hdr)
{
memset(vnet_hdr, 0, sizeof(*vnet_hdr));
if (skb_is_gso(skb)) {
struct skb_shared_info *sinfo = skb_shinfo(skb);
/* This is a hint as to how much should be linear. */
vnet_hdr->hdr_len = cpu_to_macvtap16(q, skb_headlen(skb));
vnet_hdr->gso_size = cpu_to_macvtap16(q, sinfo->gso_size);
if (sinfo->gso_type & SKB_GSO_TCPV4)
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
else if (sinfo->gso_type & SKB_GSO_TCPV6)
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
else if (sinfo->gso_type & SKB_GSO_UDP)
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
else
BUG();
if (sinfo->gso_type & SKB_GSO_TCP_ECN)
vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
} else
vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
if (skb->ip_summed == CHECKSUM_PARTIAL) {
vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
if (skb_vlan_tag_present(skb))
vnet_hdr->csum_start = cpu_to_macvtap16(q,
skb_checksum_start_offset(skb) + VLAN_HLEN);
else
vnet_hdr->csum_start = cpu_to_macvtap16(q,
skb_checksum_start_offset(skb));
vnet_hdr->csum_offset = cpu_to_macvtap16(q, skb->csum_offset);
} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
} /* else everything is zero */
}
/* Neighbour code has some assumptions on HH_DATA_MOD alignment */
#define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN)
/* Get packet from user space buffer */
static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
struct iov_iter *from, int noblock)
{
int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE);
struct sk_buff *skb;
struct macvlan_dev *vlan;
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;
bool zerocopy = false;
size_t linear;
ssize_t n;
if (q->flags & IFF_VNET_HDR) {
vnet_hdr_len = q->vnet_hdr_sz;
err = -EINVAL;
if (len < vnet_hdr_len)
goto err;
len -= vnet_hdr_len;
err = -EFAULT;
n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from);
if (n != sizeof(vnet_hdr))
goto err;
iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
macvtap16_to_cpu(q, vnet_hdr.csum_start) +
macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
macvtap16_to_cpu(q, vnet_hdr.hdr_len))
vnet_hdr.hdr_len = cpu_to_macvtap16(q,
macvtap16_to_cpu(q, vnet_hdr.csum_start) +
macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
err = -EINVAL;
if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len)
goto err;
}
err = -EINVAL;
if (unlikely(len < ETH_HLEN))
goto err;
if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
struct iov_iter i;
copylen = vnet_hdr.hdr_len ?
macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
if (copylen > good_linear)
copylen = good_linear;
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;
if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > good_linear)
linear = good_linear;
else
linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len);
}
skb = macvtap_alloc_skb(&q->sk, MACVTAP_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 && m && m->msg_control) {
struct ubuf_info *uarg = m->msg_control;
uarg->callback(uarg, false);
}
}
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 = macvtap_skb_from_vnet_hdr(q, skb, &vnet_hdr);
if (err)
goto err_kfree;
}
skb_probe_transport_header(skb, ETH_HLEN);
rcu_read_lock();
vlan = rcu_dereference(q->vlan);
/* copy skb_ubuf_info for callback when skb has no error */
if (zerocopy) {
skb_shinfo(skb)->destructor_arg = m->msg_control;
skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
}
if (vlan) {
skb->dev = vlan->dev;
dev_queue_xmit(skb);
} else {
kfree_skb(skb);
}
rcu_read_unlock();
return total_len;
err_kfree:
kfree_skb(skb);
err:
rcu_read_lock();
vlan = rcu_dereference(q->vlan);
if (vlan)
this_cpu_inc(vlan->pcpu_stats->tx_dropped);
rcu_read_unlock();
return err;
}
static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct macvtap_queue *q = file->private_data;
return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
}
/* Put packet to the user space buffer */
static ssize_t macvtap_put_user(struct macvtap_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) {
struct virtio_net_hdr vnet_hdr;
vnet_hdr_len = q->vnet_hdr_sz;
if (iov_iter_count(iter) < vnet_hdr_len)
return -EINVAL;
macvtap_skb_to_vnet_hdr(q, skb, &vnet_hdr);
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 macvtap_do_read(struct macvtap_queue *q,
struct iov_iter *to,
int noblock)
{
DEFINE_WAIT(wait);
struct sk_buff *skb;
ssize_t ret = 0;
if (!iov_iter_count(to))
return 0;
while (1) {
if (!noblock)
prepare_to_wait(sk_sleep(&q->sk), &wait,
TASK_INTERRUPTIBLE);
/* Read frames from the queue */
skb = skb_dequeue(&q->sk.sk_receive_queue);
if (skb)
break;
if (noblock) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
/* Nothing to read, let's sleep */
schedule();
}
if (skb) {
ret = macvtap_put_user(q, skb, to);
if (unlikely(ret < 0))
kfree_skb(skb);
else
consume_skb(skb);
}
if (!noblock)
finish_wait(sk_sleep(&q->sk), &wait);
return ret;
}
static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct macvtap_queue *q = file->private_data;
ssize_t len = iov_iter_count(to), ret;
ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK);
ret = min_t(ssize_t, ret, len);
if (ret > 0)
iocb->ki_pos = ret;
return ret;
}
static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q)
{
struct macvlan_dev *vlan;
ASSERT_RTNL();
vlan = rtnl_dereference(q->vlan);
if (vlan)
dev_hold(vlan->dev);
return vlan;
}
static void macvtap_put_vlan(struct macvlan_dev *vlan)
{
dev_put(vlan->dev);
}
static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
{
struct macvtap_queue *q = file->private_data;
struct macvlan_dev *vlan;
int ret;
vlan = macvtap_get_vlan(q);
if (!vlan)
return -EINVAL;
if (flags & IFF_ATTACH_QUEUE)
ret = macvtap_enable_queue(vlan->dev, file, q);
else if (flags & IFF_DETACH_QUEUE)
ret = macvtap_disable_queue(q);
else
ret = -EINVAL;
macvtap_put_vlan(vlan);
return ret;
}
static int set_offload(struct macvtap_queue *q, unsigned long arg)
{
struct macvlan_dev *vlan;
netdev_features_t features;
netdev_features_t feature_mask = 0;
vlan = rtnl_dereference(q->vlan);
if (!vlan)
return -ENOLINK;
features = vlan->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;
}
if (arg & TUN_F_UFO)
feature_mask |= NETIF_F_UFO;
}
/* 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 macvtap, 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 | NETIF_F_UFO))
features |= RX_OFFLOADS;
else
features &= ~RX_OFFLOADS;
/* tap_features are the same as features on tun/tap and
* reflect user expectations.
*/
vlan->tap_features = feature_mask;
vlan->set_features = features;
netdev_update_features(vlan->dev);
return 0;
}
/*
* provide compatibility with generic tun/tap interface
*/
static long macvtap_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)