1 files changed, 788 insertions, 0 deletions

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
new file mode 100644
index 000000000..6bb0649c0
--- /dev/null
+++ b/net/xdp/xsk.c
@@ -0,0 +1,788 @@
+// SPDX-License-Identifier: GPL-2.0
+/* XDP sockets
+ *
+ * AF_XDP sockets allows a channel between XDP programs and userspace
+ * applications.
+ * Copyright(c) 2018 Intel Corporation.
+ *
+ * Author(s): Björn Töpel <bjorn.topel@intel.com>
+ *	      Magnus Karlsson <magnus.karlsson@intel.com>
+ */
+
+#define pr_fmt(fmt) "AF_XDP: %s: " fmt, __func__
+
+#include <linux/if_xdp.h>
+#include <linux/init.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/socket.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/rculist.h>
+#include <net/xdp_sock.h>
+#include <net/xdp.h>
+
+#include "xsk_queue.h"
+#include "xdp_umem.h"
+
+#define TX_BATCH_SIZE 16
+
+static struct xdp_sock *xdp_sk(struct sock *sk)
+{
+	return (struct xdp_sock *)sk;
+}
+
+bool xsk_is_setup_for_bpf_map(struct xdp_sock *xs)
+{
+	return READ_ONCE(xs->rx) &&  READ_ONCE(xs->umem) &&
+		READ_ONCE(xs->umem->fq);
+}
+
+u64 *xsk_umem_peek_addr(struct xdp_umem *umem, u64 *addr)
+{
+	return xskq_peek_addr(umem->fq, addr);
+}
+EXPORT_SYMBOL(xsk_umem_peek_addr);
+
+void xsk_umem_discard_addr(struct xdp_umem *umem)
+{
+	xskq_discard_addr(umem->fq);
+}
+EXPORT_SYMBOL(xsk_umem_discard_addr);
+
+static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
+{
+	void *buffer;
+	u64 addr;
+	int err;
+
+	if (!xskq_peek_addr(xs->umem->fq, &addr) ||
+	    len > xs->umem->chunk_size_nohr) {
+		xs->rx_dropped++;
+		return -ENOSPC;
+	}
+
+	addr += xs->umem->headroom;
+
+	buffer = xdp_umem_get_data(xs->umem, addr);
+	memcpy(buffer, xdp->data, len);
+	err = xskq_produce_batch_desc(xs->rx, addr, len);
+	if (!err) {
+		xskq_discard_addr(xs->umem->fq);
+		xdp_return_buff(xdp);
+		return 0;
+	}
+
+	xs->rx_dropped++;
+	return err;
+}
+
+static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
+{
+	int err = xskq_produce_batch_desc(xs->rx, (u64)xdp->handle, len);
+
+	if (err)
+		xs->rx_dropped++;
+
+	return err;
+}
+
+int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
+{
+	u32 len;
+
+	if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
+		return -EINVAL;
+
+	len = xdp->data_end - xdp->data;
+
+	return (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY) ?
+		__xsk_rcv_zc(xs, xdp, len) : __xsk_rcv(xs, xdp, len);
+}
+
+void xsk_flush(struct xdp_sock *xs)
+{
+	xskq_produce_flush_desc(xs->rx);
+	xs->sk.sk_data_ready(&xs->sk);
+}
+
+int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
+{
+	u32 len = xdp->data_end - xdp->data;
+	void *buffer;
+	u64 addr;
+	int err;
+
+	if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
+		return -EINVAL;
+
+	if (!xskq_peek_addr(xs->umem->fq, &addr) ||
+	    len > xs->umem->chunk_size_nohr) {
+		xs->rx_dropped++;
+		return -ENOSPC;
+	}
+
+	addr += xs->umem->headroom;
+
+	buffer = xdp_umem_get_data(xs->umem, addr);
+	memcpy(buffer, xdp->data, len);
+	err = xskq_produce_batch_desc(xs->rx, addr, len);
+	if (!err) {
+		xskq_discard_addr(xs->umem->fq);
+		xsk_flush(xs);
+		return 0;
+	}
+
+	xs->rx_dropped++;
+	return err;
+}
+
+void xsk_umem_complete_tx(struct xdp_umem *umem, u32 nb_entries)
+{
+	xskq_produce_flush_addr_n(umem->cq, nb_entries);
+}
+EXPORT_SYMBOL(xsk_umem_complete_tx);
+
+void xsk_umem_consume_tx_done(struct xdp_umem *umem)
+{
+	struct xdp_sock *xs;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(xs, &umem->xsk_list, list) {
+		xs->sk.sk_write_space(&xs->sk);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(xsk_umem_consume_tx_done);
+
+bool xsk_umem_consume_tx(struct xdp_umem *umem, dma_addr_t *dma, u32 *len)
+{
+	struct xdp_desc desc;
+	struct xdp_sock *xs;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(xs, &umem->xsk_list, list) {
+		if (!xskq_peek_desc(xs->tx, &desc))
+			continue;
+
+		if (xskq_produce_addr_lazy(umem->cq, desc.addr))
+			goto out;
+
+		*dma = xdp_umem_get_dma(umem, desc.addr);
+		*len = desc.len;
+
+		xskq_discard_desc(xs->tx);
+		rcu_read_unlock();
+		return true;
+	}
+
+out:
+	rcu_read_unlock();
+	return false;
+}
+EXPORT_SYMBOL(xsk_umem_consume_tx);
+
+static int xsk_zc_xmit(struct sock *sk)
+{
+	struct xdp_sock *xs = xdp_sk(sk);
+	struct net_device *dev = xs->dev;
+
+	return dev->netdev_ops->ndo_xsk_async_xmit(dev, xs->queue_id);
+}
+
+static void xsk_destruct_skb(struct sk_buff *skb)
+{
+	u64 addr = (u64)(long)skb_shinfo(skb)->destructor_arg;
+	struct xdp_sock *xs = xdp_sk(skb->sk);
+	unsigned long flags;
+
+	spin_lock_irqsave(&xs->tx_completion_lock, flags);
+	WARN_ON_ONCE(xskq_produce_addr(xs->umem->cq, addr));
+	spin_unlock_irqrestore(&xs->tx_completion_lock, flags);
+
+	sock_wfree(skb);
+}
+
+static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
+			    size_t total_len)
+{
+	u32 max_batch = TX_BATCH_SIZE;
+	struct xdp_sock *xs = xdp_sk(sk);
+	bool sent_frame = false;
+	struct xdp_desc desc;
+	struct sk_buff *skb;
+	int err = 0;
+
+	mutex_lock(&xs->mutex);
+
+	if (xs->queue_id >= xs->dev->real_num_tx_queues)
+		goto out;
+
+	while (xskq_peek_desc(xs->tx, &desc)) {
+		char *buffer;
+		u64 addr;
+		u32 len;
+
+		if (max_batch-- == 0) {
+			err = -EAGAIN;
+			goto out;
+		}
+
+		len = desc.len;
+		skb = sock_alloc_send_skb(sk, len, 1, &err);
+		if (unlikely(!skb))
+			goto out;
+
+		skb_put(skb, len);
+		addr = desc.addr;
+		buffer = xdp_umem_get_data(xs->umem, addr);
+		err = skb_store_bits(skb, 0, buffer, len);
+		if (unlikely(err) || xskq_reserve_addr(xs->umem->cq)) {
+			kfree_skb(skb);
+			goto out;
+		}
+
+		skb->dev = xs->dev;
+		skb->priority = sk->sk_priority;
+		skb->mark = sk->sk_mark;
+		skb_shinfo(skb)->destructor_arg = (void *)(long)addr;
+		skb->destructor = xsk_destruct_skb;
+
+		err = dev_direct_xmit(skb, xs->queue_id);
+		xskq_discard_desc(xs->tx);
+		/* Ignore NET_XMIT_CN as packet might have been sent */
+		if (err == NET_XMIT_DROP || err == NETDEV_TX_BUSY) {
+			/* SKB completed but not sent */
+			err = -EBUSY;
+			goto out;
+		}
+
+		sent_frame = true;
+	}
+
+out:
+	if (sent_frame)
+		sk->sk_write_space(sk);
+
+	mutex_unlock(&xs->mutex);
+	return err;
+}
+
+static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
+{
+	bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+
+	if (unlikely(!xs->dev))
+		return -ENXIO;
+	if (unlikely(!(xs->dev->flags & IFF_UP)))
+		return -ENETDOWN;
+	if (unlikely(!xs->tx))
+		return -ENOBUFS;
+	if (need_wait)
+		return -EOPNOTSUPP;
+
+	return (xs->zc) ? xsk_zc_xmit(sk) : xsk_generic_xmit(sk, m, total_len);
+}
+
+static __poll_t xsk_poll(struct file *file, struct socket *sock,
+			     struct poll_table_struct *wait)
+{
+	__poll_t mask = datagram_poll(file, sock, wait);
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+
+	if (xs->rx && !xskq_empty_desc(xs->rx))
+		mask |= EPOLLIN | EPOLLRDNORM;
+	if (xs->tx && !xskq_full_desc(xs->tx))
+		mask |= EPOLLOUT | EPOLLWRNORM;
+
+	return mask;
+}
+
+static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
+			  bool umem_queue)
+{
+	struct xsk_queue *q;
+
+	if (entries == 0 || *queue || !is_power_of_2(entries))
+		return -EINVAL;
+
+	q = xskq_create(entries, umem_queue);
+	if (!q)
+		return -ENOMEM;
+
+	/* Make sure queue is ready before it can be seen by others */
+	smp_wmb();
+	WRITE_ONCE(*queue, q);
+	return 0;
+}
+
+static int xsk_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	struct net *net;
+
+	if (!sk)
+		return 0;
+
+	net = sock_net(sk);
+
+	local_bh_disable();
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
+	local_bh_enable();
+
+	if (xs->dev) {
+		struct net_device *dev = xs->dev;
+
+		/* Wait for driver to stop using the xdp socket. */
+		xdp_del_sk_umem(xs->umem, xs);
+		xs->dev = NULL;
+		synchronize_net();
+		dev_put(dev);
+	}
+
+	xskq_destroy(xs->rx);
+	xskq_destroy(xs->tx);
+
+	sock_orphan(sk);
+	sock->sk = NULL;
+
+	sk_refcnt_debug_release(sk);
+	sock_put(sk);
+
+	return 0;
+}
+
+static struct socket *xsk_lookup_xsk_from_fd(int fd)
+{
+	struct socket *sock;
+	int err;
+
+	sock = sockfd_lookup(fd, &err);
+	if (!sock)
+		return ERR_PTR(-ENOTSOCK);
+
+	if (sock->sk->sk_family != PF_XDP) {
+		sockfd_put(sock);
+		return ERR_PTR(-ENOPROTOOPT);
+	}
+
+	return sock;
+}
+
+static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
+{
+	struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr;
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	struct net_device *dev;
+	u32 flags, qid;
+	int err = 0;
+
+	if (addr_len < sizeof(struct sockaddr_xdp))
+		return -EINVAL;
+	if (sxdp->sxdp_family != AF_XDP)
+		return -EINVAL;
+
+	mutex_lock(&xs->mutex);
+	if (xs->dev) {
+		err = -EBUSY;
+		goto out_release;
+	}
+
+	dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);
+	if (!dev) {
+		err = -ENODEV;
+		goto out_release;
+	}
+
+	if (!xs->rx && !xs->tx) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	qid = sxdp->sxdp_queue_id;
+
+	if ((xs->rx && qid >= dev->real_num_rx_queues) ||
+	    (xs->tx && qid >= dev->real_num_tx_queues)) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	flags = sxdp->sxdp_flags;
+
+	if (flags & XDP_SHARED_UMEM) {
+		struct xdp_sock *umem_xs;
+		struct socket *sock;
+
+		if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY)) {
+			/* Cannot specify flags for shared sockets. */
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		if (xs->umem) {
+			/* We have already our own. */
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd);
+		if (IS_ERR(sock)) {
+			err = PTR_ERR(sock);
+			goto out_unlock;
+		}
+
+		umem_xs = xdp_sk(sock->sk);
+		if (!umem_xs->umem) {
+			/* No umem to inherit. */
+			err = -EBADF;
+			sockfd_put(sock);
+			goto out_unlock;
+		} else if (umem_xs->dev != dev || umem_xs->queue_id != qid) {
+			err = -EINVAL;
+			sockfd_put(sock);
+			goto out_unlock;
+		}
+
+		xdp_get_umem(umem_xs->umem);
+		WRITE_ONCE(xs->umem, umem_xs->umem);
+		sockfd_put(sock);
+	} else if (!xs->umem || !xdp_umem_validate_queues(xs->umem)) {
+		err = -EINVAL;
+		goto out_unlock;
+	} else {
+		/* This xsk has its own umem. */
+		xskq_set_umem(xs->umem->fq, &xs->umem->props);
+		xskq_set_umem(xs->umem->cq, &xs->umem->props);
+
+		err = xdp_umem_assign_dev(xs->umem, dev, qid, flags);
+		if (err)
+			goto out_unlock;
+	}
+
+	xs->dev = dev;
+	xs->zc = xs->umem->zc;
+	xs->queue_id = qid;
+	xskq_set_umem(xs->rx, &xs->umem->props);
+	xskq_set_umem(xs->tx, &xs->umem->props);
+	xdp_add_sk_umem(xs->umem, xs);
+
+out_unlock:
+	if (err)
+		dev_put(dev);
+out_release:
+	mutex_unlock(&xs->mutex);
+	return err;
+}
+
+static int xsk_setsockopt(struct socket *sock, int level, int optname,
+			  char __user *optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	int err;
+
+	if (level != SOL_XDP)
+		return -ENOPROTOOPT;
+
+	switch (optname) {
+	case XDP_RX_RING:
+	case XDP_TX_RING:
+	{
+		struct xsk_queue **q;
+		int entries;
+
+		if (optlen < sizeof(entries))
+			return -EINVAL;
+		if (copy_from_user(&entries, optval, sizeof(entries)))
+			return -EFAULT;
+
+		mutex_lock(&xs->mutex);
+		q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx;
+		err = xsk_init_queue(entries, q, false);
+		mutex_unlock(&xs->mutex);
+		return err;
+	}
+	case XDP_UMEM_REG:
+	{
+		struct xdp_umem_reg mr;
+		struct xdp_umem *umem;
+
+		if (copy_from_user(&mr, optval, sizeof(mr)))
+			return -EFAULT;
+
+		mutex_lock(&xs->mutex);
+		if (xs->umem) {
+			mutex_unlock(&xs->mutex);
+			return -EBUSY;
+		}
+
+		umem = xdp_umem_create(&mr);
+		if (IS_ERR(umem)) {
+			mutex_unlock(&xs->mutex);
+			return PTR_ERR(umem);
+		}
+
+		/* Make sure umem is ready before it can be seen by others */
+		smp_wmb();
+		WRITE_ONCE(xs->umem, umem);
+		mutex_unlock(&xs->mutex);
+		return 0;
+	}
+	case XDP_UMEM_FILL_RING:
+	case XDP_UMEM_COMPLETION_RING:
+	{
+		struct xsk_queue **q;
+		int entries;
+
+		if (copy_from_user(&entries, optval, sizeof(entries)))
+			return -EFAULT;
+
+		mutex_lock(&xs->mutex);
+		if (!xs->umem) {
+			mutex_unlock(&xs->mutex);
+			return -EINVAL;
+		}
+
+		q = (optname == XDP_UMEM_FILL_RING) ? &xs->umem->fq :
+			&xs->umem->cq;
+		err = xsk_init_queue(entries, q, true);
+		mutex_unlock(&xs->mutex);
+		return err;
+	}
+	default:
+		break;
+	}
+
+	return -ENOPROTOOPT;
+}
+
+static int xsk_getsockopt(struct socket *sock, int level, int optname,
+			  char __user *optval, int __user *optlen)
+{
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	int len;
+
+	if (level != SOL_XDP)
+		return -ENOPROTOOPT;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+	if (len < 0)
+		return -EINVAL;
+
+	switch (optname) {
+	case XDP_STATISTICS:
+	{
+		struct xdp_statistics stats;
+
+		if (len < sizeof(stats))
+			return -EINVAL;
+
+		mutex_lock(&xs->mutex);
+		stats.rx_dropped = xs->rx_dropped;
+		stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
+		stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
+		mutex_unlock(&xs->mutex);
+
+		if (copy_to_user(optval, &stats, sizeof(stats)))
+			return -EFAULT;
+		if (put_user(sizeof(stats), optlen))
+			return -EFAULT;
+
+		return 0;
+	}
+	case XDP_MMAP_OFFSETS:
+	{
+		struct xdp_mmap_offsets off;
+
+		if (len < sizeof(off))
+			return -EINVAL;
+
+		off.rx.producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
+		off.rx.consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
+		off.rx.desc	= offsetof(struct xdp_rxtx_ring, desc);
+		off.tx.producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
+		off.tx.consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
+		off.tx.desc	= offsetof(struct xdp_rxtx_ring, desc);
+
+		off.fr.producer = offsetof(struct xdp_umem_ring, ptrs.producer);
+		off.fr.consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
+		off.fr.desc	= offsetof(struct xdp_umem_ring, desc);
+		off.cr.producer = offsetof(struct xdp_umem_ring, ptrs.producer);
+		off.cr.consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
+		off.cr.desc	= offsetof(struct xdp_umem_ring, desc);
+
+		len = sizeof(off);
+		if (copy_to_user(optval, &off, len))
+			return -EFAULT;
+		if (put_user(len, optlen))
+			return -EFAULT;
+
+		return 0;
+	}
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int xsk_mmap(struct file *file, struct socket *sock,
+		    struct vm_area_struct *vma)
+{
+	loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+	unsigned long size = vma->vm_end - vma->vm_start;
+	struct xdp_sock *xs = xdp_sk(sock->sk);
+	struct xsk_queue *q = NULL;
+	struct xdp_umem *umem;
+	unsigned long pfn;
+	struct page *qpg;
+
+	if (offset == XDP_PGOFF_RX_RING) {
+		q = READ_ONCE(xs->rx);
+	} else if (offset == XDP_PGOFF_TX_RING) {
+		q = READ_ONCE(xs->tx);
+	} else {
+		umem = READ_ONCE(xs->umem);
+		if (!umem)
+			return -EINVAL;
+
+		/* Matches the smp_wmb() in XDP_UMEM_REG */
+		smp_rmb();
+		if (offset == XDP_UMEM_PGOFF_FILL_RING)
+			q = READ_ONCE(umem->fq);
+		else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
+			q = READ_ONCE(umem->cq);
+	}
+
+	if (!q)
+		return -EINVAL;
+
+	/* Matches the smp_wmb() in xsk_init_queue */
+	smp_rmb();
+	qpg = virt_to_head_page(q->ring);
+	if (size > (PAGE_SIZE << compound_order(qpg)))
+		return -EINVAL;
+
+	pfn = virt_to_phys(q->ring) >> PAGE_SHIFT;
+	return remap_pfn_range(vma, vma->vm_start, pfn,
+			       size, vma->vm_page_prot);
+}
+
+static struct proto xsk_proto = {
+	.name =		"XDP",
+	.owner =	THIS_MODULE,
+	.obj_size =	sizeof(struct xdp_sock),
+};
+
+static const struct proto_ops xsk_proto_ops = {
+	.family		= PF_XDP,
+	.owner		= THIS_MODULE,
+	.release	= xsk_release,
+	.bind		= xsk_bind,
+	.connect	= sock_no_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.getname	= sock_no_getname,
+	.poll		= xsk_poll,
+	.ioctl		= sock_no_ioctl,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.setsockopt	= xsk_setsockopt,
+	.getsockopt	= xsk_getsockopt,
+	.sendmsg	= xsk_sendmsg,
+	.recvmsg	= sock_no_recvmsg,
+	.mmap		= xsk_mmap,
+	.sendpage	= sock_no_sendpage,
+};
+
+static void xsk_destruct(struct sock *sk)
+{
+	struct xdp_sock *xs = xdp_sk(sk);
+
+	if (!sock_flag(sk, SOCK_DEAD))
+		return;
+
+	xdp_put_umem(xs->umem);
+
+	sk_refcnt_debug_dec(sk);
+}
+
+static int xsk_create(struct net *net, struct socket *sock, int protocol,
+		      int kern)
+{
+	struct sock *sk;
+	struct xdp_sock *xs;
+
+	if (!ns_capable(net->user_ns, CAP_NET_RAW))
+		return -EPERM;
+	if (sock->type != SOCK_RAW)
+		return -ESOCKTNOSUPPORT;
+
+	if (protocol)
+		return -EPROTONOSUPPORT;
+
+	sock->state = SS_UNCONNECTED;
+
+	sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern);
+	if (!sk)
+		return -ENOBUFS;
+
+	sock->ops = &xsk_proto_ops;
+
+	sock_init_data(sock, sk);
+
+	sk->sk_family = PF_XDP;
+
+	sk->sk_destruct = xsk_destruct;
+	sk_refcnt_debug_inc(sk);
+
+	sock_set_flag(sk, SOCK_RCU_FREE);
+
+	xs = xdp_sk(sk);
+	mutex_init(&xs->mutex);
+	spin_lock_init(&xs->tx_completion_lock);
+
+	local_bh_disable();
+	sock_prot_inuse_add(net, &xsk_proto, 1);
+	local_bh_enable();
+
+	return 0;
+}
+
+static const struct net_proto_family xsk_family_ops = {
+	.family = PF_XDP,
+	.create = xsk_create,
+	.owner	= THIS_MODULE,
+};
+
+static int __init xsk_init(void)
+{
+	int err;
+
+	err = proto_register(&xsk_proto, 0 /* no slab */);
+	if (err)
+		goto out;
+
+	err = sock_register(&xsk_family_ops);
+	if (err)
+		goto out_proto;
+
+	return 0;
+
+out_proto:
+	proto_unregister(&xsk_proto);
+out:
+	return err;
+}
+
+fs_initcall(xsk_init);