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Diffstat (limited to 'samples/bpf/xdp_fwd_kern.c')
-rw-r--r--samples/bpf/xdp_fwd_kern.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/samples/bpf/xdp_fwd_kern.c b/samples/bpf/xdp_fwd_kern.c
index e6ffc4ea06f4..a43d6953c054 100644
--- a/samples/bpf/xdp_fwd_kern.c
+++ b/samples/bpf/xdp_fwd_kern.c
@@ -104,13 +104,18 @@ static __always_inline int xdp_fwd_flags(struct xdp_md *ctx, u32 flags)
rc = bpf_fib_lookup(ctx, &fib_params, sizeof(fib_params), flags);
- /* verify egress index has xdp support
- * TO-DO bpf_map_lookup_elem(&tx_port, &key) fails with
- * cannot pass map_type 14 into func bpf_map_lookup_elem#1:
- * NOTE: without verification that egress index supports XDP
- * forwarding packets are dropped.
- */
if (rc == 0) {
+ /* Verify egress index has been configured as TX-port.
+ * (Note: User can still have inserted an egress ifindex that
+ * doesn't support XDP xmit, which will result in packet drops).
+ *
+ * Note: lookup in devmap supported since 0cdbb4b09a0.
+ * If not supported will fail with:
+ * cannot pass map_type 14 into func bpf_map_lookup_elem#1:
+ */
+ if (!bpf_map_lookup_elem(&xdp_tx_ports, &fib_params.ifindex))
+ return XDP_PASS;
+
if (h_proto == htons(ETH_P_IP))
ip_decrease_ttl(iph);
else if (h_proto == htons(ETH_P_IPV6))