[RFC PATCH 23/24] vdpa_sim: filter destination mac address

[Jason Wang]

Add a simple unicast filter to filter out the dest MAC doesn't match
to the one stored in the config.

Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 49 ++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index b21670e054ba..66d901fb4c57 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -171,6 +171,22 @@ static void vdpasim_complete(struct vdpasim_virtqueue *vq, 
size_t len)
        local_bh_enable();
 }
 
+static bool receive_filter(struct vdpasim *vdpasim, size_t len)
+{
+       bool modern = vdpasim->features & (1ULL << VIRTIO_F_VERSION_1);
+       size_t hdr_len = modern ? sizeof(struct virtio_net_hdr_v1) :
+                                 sizeof(struct virtio_net_hdr);
+
+       if (len < ETH_ALEN + hdr_len)
+               return false;
+
+       if (!strncmp(vdpasim->buffer + hdr_len,
+                    vdpasim->config.mac, ETH_ALEN))
+               return true;
+
+       return false;
+}
+
 static void vdpasim_work(struct work_struct *work)
 {
        struct vdpasim *vdpasim = container_of(work, struct
@@ -178,7 +194,6 @@ static void vdpasim_work(struct work_struct *work)
        struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
        struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
        ssize_t read, write;
-       size_t total_write;
        int pkts = 0;
        int err;
 
@@ -191,36 +206,34 @@ static void vdpasim_work(struct work_struct *work)
                goto out;
 
        while (true) {
-               total_write = 0;
                err = vringh_getdesc_iotlb(&txq->vring, &txq->riov, NULL,
                                           &txq->head, GFP_ATOMIC);
                if (err <= 0)
                        break;
 
+               read = vringh_iov_pull_iotlb(&txq->vring, &txq->riov,
+                                            vdpasim->buffer,
+                                            PAGE_SIZE);
+
+               if (!receive_filter(vdpasim, read)) {
+                       vdpasim_complete(txq, 0);
+                       continue;
+               }
+
                err = vringh_getdesc_iotlb(&rxq->vring, NULL, &rxq->wiov,
                                           &rxq->head, GFP_ATOMIC);
                if (err <= 0) {
-                       vringh_complete_iotlb(&txq->vring, txq->head, 0);
+                       vdpasim_complete(txq, 0);
                        break;
                }
 
-               while (true) {
-                       read = vringh_iov_pull_iotlb(&txq->vring, &txq->riov,
-                                                    vdpasim->buffer,
-                                                    PAGE_SIZE);
-                       if (read <= 0)
-                               break;
-
-                       write = vringh_iov_push_iotlb(&rxq->vring, &rxq->wiov,
-                                                     vdpasim->buffer, read);
-                       if (write <= 0)
-                               break;
-
-                       total_write += write;
-               }
+               write = vringh_iov_push_iotlb(&rxq->vring, &rxq->wiov,
+                                             vdpasim->buffer, read);
+               if (write <= 0)
+                       break;
 
                vdpasim_complete(txq, 0);
-               vdpasim_complete(rxq, total_write);
+               vdpasim_complete(rxq, write);
 
                if (++pkts > 4) {
                        schedule_work(&vdpasim->work);
-- 
2.20.1