From: Magnus Karlsson <magnus.karls...@intel.com>
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.
Signed-off-by: Magnus Karlsson <magnus.karls...@intel.com>
---
include/uapi/linux/if_xdp.h | 11 ++++
net/xdp/xdp_umem.c | 9 ++++
net/xdp/xdp_umem.h | 2 +
net/xdp/xsk.c | 125 +++++++++++++++++++++++++++++++++++++++++++-
4 files changed, 146 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index 118456064e01..e3593df7323c 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -20,6 +20,17 @@
#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_QUEUE 1
#define XDP_UMEM_REG 3
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index f2c0768ca63e..96395beb980e 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -97,6 +97,11 @@ static void xdp_umem_release(struct xdp_umem *umem)
kfree(umem);
}
+void xdp_get_umem(struct xdp_umem *umem)
+{
+ atomic_inc(&umem->users);
+}
+
void xdp_put_umem(struct xdp_umem *umem)
{
if (!umem)
@@ -243,3 +248,7 @@ int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg
*mr)
return err;
}
+bool xdp_umem_validate_queues(struct xdp_umem *umem)
+{
+ return umem->fq;
+}
diff --git a/net/xdp/xdp_umem.h b/net/xdp/xdp_umem.h
index b3538dd2118c..ad041b911b38 100644
--- a/net/xdp/xdp_umem.h
+++ b/net/xdp/xdp_umem.h
@@ -36,7 +36,9 @@ struct xdp_umem {
struct user_struct *user;
};
+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);
int xdp_umem_create(struct xdp_umem **umem);
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index f82f750cadc2..d99a1b830f94 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -43,6 +43,8 @@ struct xdp_sock {
/* Protects multiple processes in the control path */
struct mutex mutex;
struct xdp_umem *umem;
+ u32 ifindex;
+ u16 queue_id;
};
static struct xdp_sock *xdp_sk(struct sock *sk)
@@ -66,9 +68,18 @@ 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)
@@ -80,6 +91,11 @@ 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;
@@ -89,6 +105,113 @@ static int xsk_release(struct socket *sock)
return 0;
}
+static struct socket *xsk_lookup_xsk_from_fd(int fd, int *err)
+{
+ struct socket *sock;
+
+ *err = -ENOTSOCK;
+ sock = sockfd_lookup(fd, err);
+ if (!sock)
+ return NULL;
+
+ if (sock->sk->sk_family != PF_XDP) {
+ *err = -ENOPROTOOPT;
+ sockfd_put(sock);
+ return NULL;
+ }
+
+ *err = 0;
+ 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, &err);
+ if (!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->ifindex = sxdp->sxdp_ifindex;
+ xs->queue_id = sxdp->sxdp_queue_id;
+
+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)
{
@@ -212,7 +335,7 @@ 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,
--
2.14.1
