xsk: Extend xsk_rcv_check validation

xsk_rcv_check tests for inbound packets to see whether they match
the bound AF_XDP socket. Refactor the test into a small helper
xsk_dev_queue_valid and move the validation against xs->dev and
xs->queue_id there.

The fast-path case stays in place and allows for quick return in
xsk_dev_queue_valid. If it fails, the validation is extended to
check whether the AF_XDP socket is bound against a leased queue,
and if the case then the test is redone.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260115082603.219152-8-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 67f32a249ecb774d61ba22312ab63102d4f68fed..747865f9341d37e641963931a3112a8e56e06ab5 100644 (file)
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -324,14 +324,37 @@ static bool xsk_is_bound(struct xdp_sock *xs)
        return false;
 }
 
+static bool xsk_dev_queue_valid(const struct xdp_sock *xs,
+                               const struct xdp_rxq_info *info)
+{
+       struct net_device *dev = xs->dev;
+       u32 queue_index = xs->queue_id;
+       struct netdev_rx_queue *rxq;
+
+       if (info->dev == dev &&
+           info->queue_index == queue_index)
+               return true;
+
+       if (queue_index < dev->real_num_rx_queues) {
+               rxq = READ_ONCE(__netif_get_rx_queue(dev, queue_index)->lease);
+               if (!rxq)
+                       return false;
+
+               dev = rxq->dev;
+               queue_index = get_netdev_rx_queue_index(rxq);
+
+               return info->dev == dev &&
+                      info->queue_index == queue_index;
+       }
+       return false;
+}
+
 static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
 {
        if (!xsk_is_bound(xs))
                return -ENXIO;
-
-       if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
+       if (!xsk_dev_queue_valid(xs, xdp->rxq))
                return -EINVAL;
-
        if (len > xsk_pool_get_rx_frame_size(xs->pool) && !xs->sg) {
                xs->rx_dropped++;
                return -ENOSPC;