xsk: Add support for recvmsg()

Add support for non-blocking recvmsg() to XDP sockets. Previously,
only sendmsg() was supported by XDP socket. Now, for symmetry and the
upcoming busy-polling support, recvmsg() is added.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20201130185205.196029-4-bjorn.topel@gmail.com

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 3e33cb6..1d1e0cd 100644 (file)
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -531,6 +531,26 @@ static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
        return __xsk_sendmsg(sk);
 }
 
+static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
+{
+       bool need_wait = !(flags & MSG_DONTWAIT);
+       struct sock *sk = sock->sk;
+       struct xdp_sock *xs = xdp_sk(sk);
+
+       if (unlikely(!(xs->dev->flags & IFF_UP)))
+               return -ENETDOWN;
+       if (unlikely(!xs->rx))
+               return -ENOBUFS;
+       if (unlikely(!xsk_is_bound(xs)))
+               return -ENXIO;
+       if (unlikely(need_wait))
+               return -EOPNOTSUPP;
+
+       if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc)
+               return xsk_wakeup(xs, XDP_WAKEUP_RX);
+       return 0;
+}
+
 static __poll_t xsk_poll(struct file *file, struct socket *sock,
                             struct poll_table_struct *wait)
 {
@@ -1191,7 +1211,7 @@ static const struct proto_ops xsk_proto_ops = {
        .setsockopt     = xsk_setsockopt,
        .getsockopt     = xsk_getsockopt,
        .sendmsg        = xsk_sendmsg,
-       .recvmsg        = sock_no_recvmsg,
+       .recvmsg        = xsk_recvmsg,
        .mmap           = xsk_mmap,
        .sendpage       = sock_no_sendpage,
 };