path: root/samples/bpf/xdp_redirect_map_kern.c
diff options
authorJesper Dangaard Brouer <brouer@redhat.com>2017-08-29 16:38:06 +0200
committerDavid S. Miller <davem@davemloft.net>2017-08-29 10:51:29 -0700
commit306da4e685b415f5c875cef275001b5cdc182da9 (patch)
tree76ba2be2cdb8d5a01fa43270a66fdbf758837f99 /samples/bpf/xdp_redirect_map_kern.c
parent59a308967589f5b3f1f42793ab49bc2e18069769 (diff)
samples/bpf: xdp_redirect load XDP dummy prog on TX device
For supporting XDP_REDIRECT, a device driver must (obviously) implement the "TX" function ndo_xdp_xmit(). An additional requirement is you cannot TX out a device, unless it also have a xdp bpf program attached. This dependency is caused by the driver code need to setup XDP resources before it can ndo_xdp_xmit. Update bpf samples xdp_redirect and xdp_redirect_map to automatically attach a dummy XDP program to the configured ifindex_out device. Use the XDP flag XDP_FLAGS_UPDATE_IF_NOEXIST on the dummy load, to avoid overriding an existing XDP prog on the device. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/bpf/xdp_redirect_map_kern.c')
1 files changed, 10 insertions, 1 deletions
diff --git a/samples/bpf/xdp_redirect_map_kern.c b/samples/bpf/xdp_redirect_map_kern.c
index 2faf196e17ea..79795d41ad0d 100644
--- a/samples/bpf/xdp_redirect_map_kern.c
+++ b/samples/bpf/xdp_redirect_map_kern.c
@@ -26,6 +26,9 @@ struct bpf_map_def SEC("maps") tx_port = {
.max_entries = 100,
+/* Count RX packets, as XDP bpf_prog doesn't get direct TX-success
+ * feedback. Redirect TX errors can be caught via a tracepoint.
+ */
struct bpf_map_def SEC("maps") rxcnt = {
.key_size = sizeof(u32),
@@ -33,7 +36,6 @@ struct bpf_map_def SEC("maps") rxcnt = {
.max_entries = 1,
static void swap_src_dst_mac(void *data)
unsigned short *p = data;
@@ -80,4 +82,11 @@ int xdp_redirect_map_prog(struct xdp_md *ctx)
return bpf_redirect_map(&tx_port, vport, 0);
+/* Redirect require an XDP bpf_prog loaded on the TX device */
+int xdp_redirect_dummy(struct xdp_md *ctx)
+ return XDP_PASS;
char _license[] SEC("license") = "GPL";