1 #include <linux/etherdevice.h>
2 #include <linux/if_macvlan.h>
3 #include <linux/if_vlan.h>
4 #include <linux/interrupt.h>
5 #include <linux/nsproxy.h>
6 #include <linux/compat.h>
7 #include <linux/if_tun.h>
8 #include <linux/module.h>
9 #include <linux/skbuff.h>
10 #include <linux/cache.h>
11 #include <linux/sched.h>
12 #include <linux/types.h>
13 #include <linux/slab.h>
14 #include <linux/wait.h>
15 #include <linux/cdev.h>
16 #include <linux/idr.h>
18 #include <linux/uio.h>
20 #include <net/net_namespace.h>
21 #include <net/rtnetlink.h>
23 #include <linux/virtio_net.h>
26 * A macvtap queue is the central object of this driver, it connects
27 * an open character device to a macvlan interface. There can be
28 * multiple queues on one interface, which map back to queues
29 * implemented in hardware on the underlying device.
31 * macvtap_proto is used to allocate queues through the sock allocation
35 struct macvtap_queue {
40 struct macvlan_dev __rcu *vlan;
45 struct list_head next;
48 #define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
50 #define MACVTAP_VNET_LE 0x80000000
52 static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val)
54 return __virtio16_to_cpu(q->flags & MACVTAP_VNET_LE, val);
57 static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val)
59 return __cpu_to_virtio16(q->flags & MACVTAP_VNET_LE, val);
62 static struct proto macvtap_proto = {
65 .obj_size = sizeof (struct macvtap_queue),
69 * Variables for dealing with macvtaps device numbers.
71 static dev_t macvtap_major;
72 #define MACVTAP_NUM_DEVS (1U << MINORBITS)
73 static DEFINE_MUTEX(minor_lock);
74 static DEFINE_IDR(minor_idr);
76 #define GOODCOPY_LEN 128
77 static struct class *macvtap_class;
78 static struct cdev macvtap_cdev;
80 static const struct proto_ops macvtap_socket_ops;
82 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
83 NETIF_F_TSO6 | NETIF_F_UFO)
84 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
85 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG)
87 static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev)
89 return rcu_dereference(dev->rx_handler_data);
94 * The macvtap_queue and the macvlan_dev are loosely coupled, the
95 * pointers from one to the other can only be read while rcu_read_lock
98 * Both the file and the macvlan_dev hold a reference on the macvtap_queue
99 * through sock_hold(&q->sk). When the macvlan_dev goes away first,
100 * q->vlan becomes inaccessible. When the files gets closed,
101 * macvtap_get_queue() fails.
103 * There may still be references to the struct sock inside of the
104 * queue from outbound SKBs, but these never reference back to the
105 * file or the dev. The data structure is freed through __sk_free
106 * when both our references and any pending SKBs are gone.
109 static int macvtap_enable_queue(struct net_device *dev, struct file *file,
110 struct macvtap_queue *q)
112 struct macvlan_dev *vlan = netdev_priv(dev);
121 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
122 q->queue_index = vlan->numvtaps;
131 static int macvtap_set_queue(struct net_device *dev, struct file *file,
132 struct macvtap_queue *q)
134 struct macvlan_dev *vlan = netdev_priv(dev);
136 if (vlan->numqueues == MAX_MACVTAP_QUEUES)
139 rcu_assign_pointer(q->vlan, vlan);
140 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
144 q->queue_index = vlan->numvtaps;
146 file->private_data = q;
147 list_add_tail(&q->next, &vlan->queue_list);
155 static int macvtap_disable_queue(struct macvtap_queue *q)
157 struct macvlan_dev *vlan;
158 struct macvtap_queue *nq;
164 vlan = rtnl_dereference(q->vlan);
167 int index = q->queue_index;
168 BUG_ON(index >= vlan->numvtaps);
169 nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]);
170 nq->queue_index = index;
172 rcu_assign_pointer(vlan->taps[index], nq);
173 RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL);
183 * The file owning the queue got closed, give up both
184 * the reference that the files holds as well as the
185 * one from the macvlan_dev if that still exists.
187 * Using the spinlock makes sure that we don't get
188 * to the queue again after destroying it.
190 static void macvtap_put_queue(struct macvtap_queue *q)
192 struct macvlan_dev *vlan;
195 vlan = rtnl_dereference(q->vlan);
199 BUG_ON(macvtap_disable_queue(q));
202 RCU_INIT_POINTER(q->vlan, NULL);
204 list_del_init(&q->next);
214 * Select a queue based on the rxq of the device on which this packet
215 * arrived. If the incoming device is not mq, calculate a flow hash
216 * to select a queue. If all fails, find the first available queue.
217 * Cache vlan->numvtaps since it can become zero during the execution
220 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
223 struct macvlan_dev *vlan = netdev_priv(dev);
224 struct macvtap_queue *tap = NULL;
225 /* Access to taps array is protected by rcu, but access to numvtaps
226 * isn't. Below we use it to lookup a queue, but treat it as a hint
227 * and validate that the result isn't NULL - in case we are
228 * racing against queue removal.
230 int numvtaps = ACCESS_ONCE(vlan->numvtaps);
236 /* Check if we can use flow to select a queue */
237 rxq = skb_get_hash(skb);
239 tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
243 if (likely(skb_rx_queue_recorded(skb))) {
244 rxq = skb_get_rx_queue(skb);
246 while (unlikely(rxq >= numvtaps))
249 tap = rcu_dereference(vlan->taps[rxq]);
253 tap = rcu_dereference(vlan->taps[0]);
259 * The net_device is going away, give up the reference
260 * that it holds on all queues and safely set the pointer
261 * from the queues to NULL.
263 static void macvtap_del_queues(struct net_device *dev)
265 struct macvlan_dev *vlan = netdev_priv(dev);
266 struct macvtap_queue *q, *tmp;
269 list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) {
270 list_del_init(&q->next);
271 RCU_INIT_POINTER(q->vlan, NULL);
277 BUG_ON(vlan->numvtaps);
278 BUG_ON(vlan->numqueues);
279 /* guarantee that any future macvtap_set_queue will fail */
280 vlan->numvtaps = MAX_MACVTAP_QUEUES;
283 static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
285 struct sk_buff *skb = *pskb;
286 struct net_device *dev = skb->dev;
287 struct macvlan_dev *vlan;
288 struct macvtap_queue *q;
289 netdev_features_t features = TAP_FEATURES;
291 vlan = macvtap_get_vlan_rcu(dev);
293 return RX_HANDLER_PASS;
295 q = macvtap_get_queue(dev, skb);
297 return RX_HANDLER_PASS;
299 if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
302 skb_push(skb, ETH_HLEN);
304 /* Apply the forward feature mask so that we perform segmentation
305 * according to users wishes. This only works if VNET_HDR is
308 if (q->flags & IFF_VNET_HDR)
309 features |= vlan->tap_features;
310 if (netif_needs_gso(skb, features)) {
311 struct sk_buff *segs = __skb_gso_segment(skb, features, false);
317 skb_queue_tail(&q->sk.sk_receive_queue, skb);
323 struct sk_buff *nskb = segs->next;
326 skb_queue_tail(&q->sk.sk_receive_queue, segs);
330 /* If we receive a partial checksum and the tap side
331 * doesn't support checksum offload, compute the checksum.
332 * Note: it doesn't matter which checksum feature to
333 * check, we either support them all or none.
335 if (skb->ip_summed == CHECKSUM_PARTIAL &&
336 !(features & NETIF_F_ALL_CSUM) &&
337 skb_checksum_help(skb))
339 skb_queue_tail(&q->sk.sk_receive_queue, skb);
343 wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
344 return RX_HANDLER_CONSUMED;
347 /* Count errors/drops only here, thus don't care about args. */
348 macvlan_count_rx(vlan, 0, 0, 0);
350 return RX_HANDLER_CONSUMED;
353 static int macvtap_get_minor(struct macvlan_dev *vlan)
355 int retval = -ENOMEM;
357 mutex_lock(&minor_lock);
358 retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL);
360 vlan->minor = retval;
361 } else if (retval == -ENOSPC) {
362 printk(KERN_ERR "too many macvtap devices\n");
365 mutex_unlock(&minor_lock);
366 return retval < 0 ? retval : 0;
369 static void macvtap_free_minor(struct macvlan_dev *vlan)
371 mutex_lock(&minor_lock);
373 idr_remove(&minor_idr, vlan->minor);
376 mutex_unlock(&minor_lock);
379 static struct net_device *dev_get_by_macvtap_minor(int minor)
381 struct net_device *dev = NULL;
382 struct macvlan_dev *vlan;
384 mutex_lock(&minor_lock);
385 vlan = idr_find(&minor_idr, minor);
390 mutex_unlock(&minor_lock);
394 static int macvtap_newlink(struct net *src_net,
395 struct net_device *dev,
397 struct nlattr *data[])
399 struct macvlan_dev *vlan = netdev_priv(dev);
402 INIT_LIST_HEAD(&vlan->queue_list);
404 /* Since macvlan supports all offloads by default, make
405 * tap support all offloads also.
407 vlan->tap_features = TUN_OFFLOADS;
409 err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan);
413 /* Don't put anything that may fail after macvlan_common_newlink
414 * because we can't undo what it does.
416 return macvlan_common_newlink(src_net, dev, tb, data);
419 static void macvtap_dellink(struct net_device *dev,
420 struct list_head *head)
422 netdev_rx_handler_unregister(dev);
423 macvtap_del_queues(dev);
424 macvlan_dellink(dev, head);
427 static void macvtap_setup(struct net_device *dev)
429 macvlan_common_setup(dev);
430 dev->tx_queue_len = TUN_READQ_SIZE;
433 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
435 .setup = macvtap_setup,
436 .newlink = macvtap_newlink,
437 .dellink = macvtap_dellink,
441 static void macvtap_sock_write_space(struct sock *sk)
443 wait_queue_head_t *wqueue;
445 if (!sock_writeable(sk) ||
446 !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
449 wqueue = sk_sleep(sk);
450 if (wqueue && waitqueue_active(wqueue))
451 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
454 static void macvtap_sock_destruct(struct sock *sk)
456 skb_queue_purge(&sk->sk_receive_queue);
459 static int macvtap_open(struct inode *inode, struct file *file)
461 struct net *net = current->nsproxy->net_ns;
462 struct net_device *dev;
463 struct macvtap_queue *q;
467 dev = dev_get_by_macvtap_minor(iminor(inode));
472 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
477 RCU_INIT_POINTER(q->sock.wq, &q->wq);
478 init_waitqueue_head(&q->wq.wait);
479 q->sock.type = SOCK_RAW;
480 q->sock.state = SS_CONNECTED;
482 q->sock.ops = &macvtap_socket_ops;
483 sock_init_data(&q->sock, &q->sk);
484 q->sk.sk_write_space = macvtap_sock_write_space;
485 q->sk.sk_destruct = macvtap_sock_destruct;
486 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
487 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
490 * so far only KVM virtio_net uses macvtap, enable zero copy between
491 * guest kernel and host kernel when lower device supports zerocopy
493 * The macvlan supports zerocopy iff the lower device supports zero
494 * copy so we don't have to look at the lower device directly.
496 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
497 sock_set_flag(&q->sk, SOCK_ZEROCOPY);
499 err = macvtap_set_queue(dev, file, q);
511 static int macvtap_release(struct inode *inode, struct file *file)
513 struct macvtap_queue *q = file->private_data;
514 macvtap_put_queue(q);
518 static unsigned int macvtap_poll(struct file *file, poll_table * wait)
520 struct macvtap_queue *q = file->private_data;
521 unsigned int mask = POLLERR;
527 poll_wait(file, &q->wq.wait, wait);
529 if (!skb_queue_empty(&q->sk.sk_receive_queue))
530 mask |= POLLIN | POLLRDNORM;
532 if (sock_writeable(&q->sk) ||
533 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
534 sock_writeable(&q->sk)))
535 mask |= POLLOUT | POLLWRNORM;
541 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
542 size_t len, size_t linear,
543 int noblock, int *err)
547 /* Under a page? Don't bother with paged skb. */
548 if (prepad + len < PAGE_SIZE || !linear)
551 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
556 skb_reserve(skb, prepad);
557 skb_put(skb, linear);
558 skb->data_len = len - linear;
559 skb->len += len - linear;
565 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
566 * be shared with the tun/tap driver.
568 static int macvtap_skb_from_vnet_hdr(struct macvtap_queue *q,
570 struct virtio_net_hdr *vnet_hdr)
572 unsigned short gso_type = 0;
573 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
574 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
575 case VIRTIO_NET_HDR_GSO_TCPV4:
576 gso_type = SKB_GSO_TCPV4;
578 case VIRTIO_NET_HDR_GSO_TCPV6:
579 gso_type = SKB_GSO_TCPV6;
581 case VIRTIO_NET_HDR_GSO_UDP:
582 gso_type = SKB_GSO_UDP;
588 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
589 gso_type |= SKB_GSO_TCP_ECN;
591 if (vnet_hdr->gso_size == 0)
595 if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
596 if (!skb_partial_csum_set(skb, macvtap16_to_cpu(q, vnet_hdr->csum_start),
597 macvtap16_to_cpu(q, vnet_hdr->csum_offset)))
601 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
602 skb_shinfo(skb)->gso_size = macvtap16_to_cpu(q, vnet_hdr->gso_size);
603 skb_shinfo(skb)->gso_type = gso_type;
605 /* Header must be checked, and gso_segs computed. */
606 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
607 skb_shinfo(skb)->gso_segs = 0;
612 static void macvtap_skb_to_vnet_hdr(struct macvtap_queue *q,
613 const struct sk_buff *skb,
614 struct virtio_net_hdr *vnet_hdr)
616 memset(vnet_hdr, 0, sizeof(*vnet_hdr));
618 if (skb_is_gso(skb)) {
619 struct skb_shared_info *sinfo = skb_shinfo(skb);
621 /* This is a hint as to how much should be linear. */
622 vnet_hdr->hdr_len = cpu_to_macvtap16(q, skb_headlen(skb));
623 vnet_hdr->gso_size = cpu_to_macvtap16(q, sinfo->gso_size);
624 if (sinfo->gso_type & SKB_GSO_TCPV4)
625 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
626 else if (sinfo->gso_type & SKB_GSO_TCPV6)
627 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
628 else if (sinfo->gso_type & SKB_GSO_UDP)
629 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
632 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
633 vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
635 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
637 if (skb->ip_summed == CHECKSUM_PARTIAL) {
638 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
639 if (skb_vlan_tag_present(skb))
640 vnet_hdr->csum_start = cpu_to_macvtap16(q,
641 skb_checksum_start_offset(skb) + VLAN_HLEN);
643 vnet_hdr->csum_start = cpu_to_macvtap16(q,
644 skb_checksum_start_offset(skb));
645 vnet_hdr->csum_offset = cpu_to_macvtap16(q, skb->csum_offset);
646 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
647 vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
648 } /* else everything is zero */
651 /* Neighbour code has some assumptions on HH_DATA_MOD alignment */
652 #define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN)
654 /* Get packet from user space buffer */
655 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
656 struct iov_iter *from, int noblock)
658 int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE);
660 struct macvlan_dev *vlan;
661 unsigned long total_len = iov_iter_count(from);
662 unsigned long len = total_len;
664 struct virtio_net_hdr vnet_hdr = { 0 };
665 int vnet_hdr_len = 0;
667 bool zerocopy = false;
671 if (q->flags & IFF_VNET_HDR) {
672 vnet_hdr_len = q->vnet_hdr_sz;
675 if (len < vnet_hdr_len)
680 n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from);
681 if (n != sizeof(vnet_hdr))
683 iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
684 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
685 macvtap16_to_cpu(q, vnet_hdr.csum_start) +
686 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
687 macvtap16_to_cpu(q, vnet_hdr.hdr_len))
688 vnet_hdr.hdr_len = cpu_to_macvtap16(q,
689 macvtap16_to_cpu(q, vnet_hdr.csum_start) +
690 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
692 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len)
697 if (unlikely(len < ETH_HLEN))
700 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
703 copylen = vnet_hdr.hdr_len ?
704 macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
705 if (copylen > good_linear)
706 copylen = good_linear;
709 iov_iter_advance(&i, copylen);
710 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
716 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > good_linear)
717 linear = good_linear;
719 linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len);
722 skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen,
723 linear, noblock, &err);
728 err = zerocopy_sg_from_iter(skb, from);
730 err = skb_copy_datagram_from_iter(skb, 0, from, len);
731 if (!err && m && m->msg_control) {
732 struct ubuf_info *uarg = m->msg_control;
733 uarg->callback(uarg, false);
740 skb_set_network_header(skb, ETH_HLEN);
741 skb_reset_mac_header(skb);
742 skb->protocol = eth_hdr(skb)->h_proto;
745 err = macvtap_skb_from_vnet_hdr(q, skb, &vnet_hdr);
750 skb_probe_transport_header(skb, ETH_HLEN);
753 vlan = rcu_dereference(q->vlan);
754 /* copy skb_ubuf_info for callback when skb has no error */
756 skb_shinfo(skb)->destructor_arg = m->msg_control;
757 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
758 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
761 skb->dev = vlan->dev;
775 vlan = rcu_dereference(q->vlan);
777 this_cpu_inc(vlan->pcpu_stats->tx_dropped);
783 static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
785 struct file *file = iocb->ki_filp;
786 struct macvtap_queue *q = file->private_data;
788 return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
791 /* Put packet to the user space buffer */
792 static ssize_t macvtap_put_user(struct macvtap_queue *q,
793 const struct sk_buff *skb,
794 struct iov_iter *iter)
797 int vnet_hdr_len = 0;
801 if (q->flags & IFF_VNET_HDR) {
802 struct virtio_net_hdr vnet_hdr;
803 vnet_hdr_len = q->vnet_hdr_sz;
804 if (iov_iter_count(iter) < vnet_hdr_len)
807 macvtap_skb_to_vnet_hdr(q, skb, &vnet_hdr);
809 if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
813 iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
815 total = vnet_hdr_len;
818 if (skb_vlan_tag_present(skb)) {
823 veth.h_vlan_proto = skb->vlan_proto;
824 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
826 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
829 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
830 if (ret || !iov_iter_count(iter))
833 ret = copy_to_iter(&veth, sizeof(veth), iter);
834 if (ret != sizeof(veth) || !iov_iter_count(iter))
838 ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
839 skb->len - vlan_offset);
842 return ret ? ret : total;
845 static ssize_t macvtap_do_read(struct macvtap_queue *q,
853 if (!iov_iter_count(to))
858 prepare_to_wait(sk_sleep(&q->sk), &wait,
861 /* Read frames from the queue */
862 skb = skb_dequeue(&q->sk.sk_receive_queue);
869 if (signal_pending(current)) {
873 /* Nothing to read, let's sleep */
877 ret = macvtap_put_user(q, skb, to);
878 if (unlikely(ret < 0))
884 finish_wait(sk_sleep(&q->sk), &wait);
888 static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to)
890 struct file *file = iocb->ki_filp;
891 struct macvtap_queue *q = file->private_data;
892 ssize_t len = iov_iter_count(to), ret;
894 ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK);
895 ret = min_t(ssize_t, ret, len);
901 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q)
903 struct macvlan_dev *vlan;
906 vlan = rtnl_dereference(q->vlan);
913 static void macvtap_put_vlan(struct macvlan_dev *vlan)
918 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
920 struct macvtap_queue *q = file->private_data;
921 struct macvlan_dev *vlan;
924 vlan = macvtap_get_vlan(q);
928 if (flags & IFF_ATTACH_QUEUE)
929 ret = macvtap_enable_queue(vlan->dev, file, q);
930 else if (flags & IFF_DETACH_QUEUE)
931 ret = macvtap_disable_queue(q);
935 macvtap_put_vlan(vlan);
939 static int set_offload(struct macvtap_queue *q, unsigned long arg)
941 struct macvlan_dev *vlan;
942 netdev_features_t features;
943 netdev_features_t feature_mask = 0;
945 vlan = rtnl_dereference(q->vlan);
949 features = vlan->dev->features;
951 if (arg & TUN_F_CSUM) {
952 feature_mask = NETIF_F_HW_CSUM;
954 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
955 if (arg & TUN_F_TSO_ECN)
956 feature_mask |= NETIF_F_TSO_ECN;
957 if (arg & TUN_F_TSO4)
958 feature_mask |= NETIF_F_TSO;
959 if (arg & TUN_F_TSO6)
960 feature_mask |= NETIF_F_TSO6;
964 feature_mask |= NETIF_F_UFO;
967 /* tun/tap driver inverts the usage for TSO offloads, where
968 * setting the TSO bit means that the userspace wants to
969 * accept TSO frames and turning it off means that user space
970 * does not support TSO.
971 * For macvtap, we have to invert it to mean the same thing.
972 * When user space turns off TSO, we turn off GSO/LRO so that
973 * user-space will not receive TSO frames.
975 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
976 features |= RX_OFFLOADS;
978 features &= ~RX_OFFLOADS;
980 /* tap_features are the same as features on tun/tap and
981 * reflect user expectations.
983 vlan->tap_features = feature_mask;
984 vlan->set_features = features;
985 netdev_update_features(vlan->dev);
991 * provide compatibility with generic tun/tap interface
993 static long macvtap_ioctl(struct file *file, unsigned int cmd,
996 struct macvtap_queue *q = file->private_data;
997 struct macvlan_dev *vlan;
998 void __user *argp = (void __user *)arg;
999 struct ifreq __user *ifr = argp;
1000 unsigned int __user *up = argp;
1002 int __user *sp = argp;
1009 /* ignore the name, just look at flags */
1010 if (get_user(u, &ifr->ifr_flags))
1014 if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP))
1017 q->flags = (q->flags & ~MACVTAP_FEATURES) | u;
1023 vlan = macvtap_get_vlan(q);
1031 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1032 put_user(u, &ifr->ifr_flags))
1034 macvtap_put_vlan(vlan);
1039 if (get_user(u, &ifr->ifr_flags))
1042 ret = macvtap_ioctl_set_queue(file, u);
1046 case TUNGETFEATURES:
1047 if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up))
1052 if (get_user(u, up))
1055 q->sk.sk_sndbuf = u;
1058 case TUNGETVNETHDRSZ:
1060 if (put_user(s, sp))
1064 case TUNSETVNETHDRSZ:
1065 if (get_user(s, sp))
1067 if (s < (int)sizeof(struct virtio_net_hdr))
1074 s = !!(q->flags & MACVTAP_VNET_LE);
1075 if (put_user(s, sp))
1080 if (get_user(s, sp))
1083 q->flags |= MACVTAP_VNET_LE;
1085 q->flags &= ~MACVTAP_VNET_LE;
1089 /* let the user check for future flags */
1090 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
1091 TUN_F_TSO_ECN | TUN_F_UFO))
1095 ret = set_offload(q, arg);
1101 vlan = macvtap_get_vlan(q);
1107 u = vlan->dev->type;
1108 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1109 copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) ||
1110 put_user(u, &ifr->ifr_hwaddr.sa_family))
1112 macvtap_put_vlan(vlan);
1117 if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
1120 vlan = macvtap_get_vlan(q);
1125 ret = dev_set_mac_address(vlan->dev, &sa);
1126 macvtap_put_vlan(vlan);
1135 #ifdef CONFIG_COMPAT
1136 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
1139 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1143 static const struct file_operations macvtap_fops = {
1144 .owner = THIS_MODULE,
1145 .open = macvtap_open,
1146 .release = macvtap_release,
1147 .read_iter = macvtap_read_iter,
1148 .write_iter = macvtap_write_iter,
1149 .poll = macvtap_poll,
1150 .llseek = no_llseek,
1151 .unlocked_ioctl = macvtap_ioctl,
1152 #ifdef CONFIG_COMPAT
1153 .compat_ioctl = macvtap_compat_ioctl,
1157 static int macvtap_sendmsg(struct socket *sock, struct msghdr *m,
1160 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1161 return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
1164 static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
1165 size_t total_len, int flags)
1167 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1169 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1171 ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
1172 if (ret > total_len) {
1173 m->msg_flags |= MSG_TRUNC;
1174 ret = flags & MSG_TRUNC ? ret : total_len;
1179 /* Ops structure to mimic raw sockets with tun */
1180 static const struct proto_ops macvtap_socket_ops = {
1181 .sendmsg = macvtap_sendmsg,
1182 .recvmsg = macvtap_recvmsg,
1185 /* Get an underlying socket object from tun file. Returns error unless file is
1186 * attached to a device. The returned object works like a packet socket, it
1187 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1188 * holding a reference to the file for as long as the socket is in use. */
1189 struct socket *macvtap_get_socket(struct file *file)
1191 struct macvtap_queue *q;
1192 if (file->f_op != &macvtap_fops)
1193 return ERR_PTR(-EINVAL);
1194 q = file->private_data;
1196 return ERR_PTR(-EBADFD);
1199 EXPORT_SYMBOL_GPL(macvtap_get_socket);
1201 static int macvtap_device_event(struct notifier_block *unused,
1202 unsigned long event, void *ptr)
1204 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1205 struct macvlan_dev *vlan;
1206 struct device *classdev;
1210 if (dev->rtnl_link_ops != &macvtap_link_ops)
1213 vlan = netdev_priv(dev);
1216 case NETDEV_REGISTER:
1217 /* Create the device node here after the network device has
1218 * been registered but before register_netdevice has
1221 err = macvtap_get_minor(vlan);
1223 return notifier_from_errno(err);
1225 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1226 classdev = device_create(macvtap_class, &dev->dev, devt,
1227 dev, "tap%d", dev->ifindex);
1228 if (IS_ERR(classdev)) {
1229 macvtap_free_minor(vlan);
1230 return notifier_from_errno(PTR_ERR(classdev));
1233 case NETDEV_UNREGISTER:
1234 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1235 device_destroy(macvtap_class, devt);
1236 macvtap_free_minor(vlan);
1243 static struct notifier_block macvtap_notifier_block __read_mostly = {
1244 .notifier_call = macvtap_device_event,
1247 static int macvtap_init(void)
1251 err = alloc_chrdev_region(&macvtap_major, 0,
1252 MACVTAP_NUM_DEVS, "macvtap");
1256 cdev_init(&macvtap_cdev, &macvtap_fops);
1257 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
1261 macvtap_class = class_create(THIS_MODULE, "macvtap");
1262 if (IS_ERR(macvtap_class)) {
1263 err = PTR_ERR(macvtap_class);
1267 err = register_netdevice_notifier(&macvtap_notifier_block);
1271 err = macvlan_link_register(&macvtap_link_ops);
1278 unregister_netdevice_notifier(&macvtap_notifier_block);
1280 class_unregister(macvtap_class);
1282 cdev_del(&macvtap_cdev);
1284 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1288 module_init(macvtap_init);
1290 static void macvtap_exit(void)
1292 rtnl_link_unregister(&macvtap_link_ops);
1293 unregister_netdevice_notifier(&macvtap_notifier_block);
1294 class_unregister(macvtap_class);
1295 cdev_del(&macvtap_cdev);
1296 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1298 module_exit(macvtap_exit);
1300 MODULE_ALIAS_RTNL_LINK("macvtap");
1301 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
1302 MODULE_LICENSE("GPL");