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Commit 965a9909 authored by Magnus Karlsson's avatar Magnus Karlsson Committed by Alexei Starovoitov
Browse files

xsk: add support for bind for Rx 



Here, the bind syscall is added. Binding an AF_XDP socket, means
associating the socket to an umem, a netdev and a queue index. This
can be done in two ways.

The first way, creating a "socket from scratch". Create the umem using
the XDP_UMEM_REG setsockopt and an associated fill queue with
XDP_UMEM_FILL_QUEUE. Create the Rx queue using the XDP_RX_QUEUE
setsockopt. Call bind passing ifindex and queue index ("channel" in
ethtool speak).

The second way to bind a socket, is simply skipping the
umem/netdev/queue index, and passing another already setup AF_XDP
socket. The new socket will then have the same umem/netdev/queue index
as the parent so it will share the same umem. You must also set the
flags field in the socket address to XDP_SHARED_UMEM.

v2: Use PTR_ERR instead of passing error variable explicitly.

Signed-off-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b9b6b68e

include/net/xdp_sock.h

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ struct xdp_sock { 
	struct xsk_queue *rx;

	struct net_device *dev;

	struct xdp_umem *umem;

	u16 queue_id;

	/* Protects multiple processes in the control path */

	struct mutex mutex;

};

include/uapi/linux/if_xdp.h

+11 −0
Original line number Diff line number Diff line
@@ -21,6 +21,17 @@ 


#include <linux/types.h>



/* Options for the sxdp_flags field */

#define XDP_SHARED_UMEM 1



struct sockaddr_xdp {

	__u16 sxdp_family;

	__u32 sxdp_ifindex;

	__u32 sxdp_queue_id;

	__u32 sxdp_shared_umem_fd;

	__u16 sxdp_flags;

};



/* XDP socket options */

#define XDP_RX_RING			1

#define XDP_UMEM_REG			3

net/xdp/xdp_umem.c

+5 −0
Original line number Diff line number Diff line
@@ -248,3 +248,8 @@ int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) 
	put_pid(umem->pid);

	return err;

}



bool xdp_umem_validate_queues(struct xdp_umem *umem)

{

	return umem->fq;

}

net/xdp/xdp_umem.h

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ struct xdp_umem { 
	struct work_struct work;

};



bool xdp_umem_validate_queues(struct xdp_umem *umem);

int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr);

void xdp_get_umem(struct xdp_umem *umem);

void xdp_put_umem(struct xdp_umem *umem);

net/xdp/xsk.c

+123 −1
Original line number Diff line number Diff line
@@ -57,9 +57,18 @@ static int xsk_init_queue(u32 entries, struct xsk_queue **queue, 
	return 0;

}



static void __xsk_release(struct xdp_sock *xs)

{

	/* Wait for driver to stop using the xdp socket. */

	synchronize_net();



	dev_put(xs->dev);

}



static int xsk_release(struct socket *sock)

{

	struct sock *sk = sock->sk;

	struct xdp_sock *xs = xdp_sk(sk);

	struct net *net;



	if (!sk)
@@ -71,6 +80,11 @@ static int xsk_release(struct socket *sock) 
	sock_prot_inuse_add(net, sk->sk_prot, -1);

	local_bh_enable();



	if (xs->dev) {

		__xsk_release(xs);

		xs->dev = NULL;

	}



	sock_orphan(sk);

	sock->sk = NULL;
@@ -80,6 +94,114 @@ static int xsk_release(struct socket *sock) 
	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 net_device *dev, *dev_curr;

	struct xdp_sock *xs = xdp_sk(sk);

	struct xdp_umem *old_umem = NULL;

	int err = 0;



	if (addr_len < sizeof(struct sockaddr_xdp))

		return -EINVAL;

	if (sxdp->sxdp_family != AF_XDP)

		return -EINVAL;



	mutex_lock(&xs->mutex);

	dev_curr = xs->dev;

	dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);

	if (!dev) {

		err = -ENODEV;

		goto out_release;

	}



	if (!xs->rx) {

		err = -EINVAL;

		goto out_unlock;

	}



	if (sxdp->sxdp_queue_id >= dev->num_rx_queues) {

		err = -EINVAL;

		goto out_unlock;

	}



	if (sxdp->sxdp_flags & XDP_SHARED_UMEM) {

		struct xdp_sock *umem_xs;

		struct socket *sock;



		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 != sxdp->sxdp_queue_id) {

			err = -EINVAL;

			sockfd_put(sock);

			goto out_unlock;

		}



		xdp_get_umem(umem_xs->umem);

		old_umem = xs->umem;

		xs->umem = umem_xs->umem;

		sockfd_put(sock);

	} else if (!xs->umem || !xdp_umem_validate_queues(xs->umem)) {

		err = -EINVAL;

		goto out_unlock;

	}



	/* Rebind? */

	if (dev_curr && (dev_curr != dev ||

			 xs->queue_id != sxdp->sxdp_queue_id)) {

		__xsk_release(xs);

		if (old_umem)

			xdp_put_umem(old_umem);

	}



	xs->dev = dev;

	xs->queue_id = sxdp->sxdp_queue_id;



	xskq_set_umem(xs->rx, &xs->umem->props);



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)

{
@@ -203,7 +325,7 @@ static const struct proto_ops xsk_proto_ops = { 
	.family =	PF_XDP,

	.owner =	THIS_MODULE,

	.release =	xsk_release,

	.bind =		sock_no_bind,

	.bind =		xsk_bind,

	.connect =	sock_no_connect,

	.socketpair =	sock_no_socketpair,

	.accept =	sock_no_accept,