From 306da4e685b415f5c875cef275001b5cdc182da9 Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Tue, 29 Aug 2017 16:38:06 +0200 Subject: 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 Signed-off-by: David S. Miller --- samples/bpf/xdp_redirect_kern.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'samples/bpf/xdp_redirect_kern.c') diff --git a/samples/bpf/xdp_redirect_kern.c b/samples/bpf/xdp_redirect_kern.c index a34ad457a684..1c90288d0203 100644 --- a/samples/bpf/xdp_redirect_kern.c +++ b/samples/bpf/xdp_redirect_kern.c @@ -26,6 +26,9 @@ struct bpf_map_def SEC("maps") tx_port = { .max_entries = 1, }; +/* 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 = { .type = BPF_MAP_TYPE_PERCPU_ARRAY, .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; @@ -78,4 +80,11 @@ int xdp_redirect_prog(struct xdp_md *ctx) return bpf_redirect(*ifindex, 0); } +/* Redirect require an XDP bpf_prog loaded on the TX device */ +SEC("xdp_redirect_dummy") +int xdp_redirect_dummy(struct xdp_md *ctx) +{ + return XDP_PASS; +} + char _license[] SEC("license") = "GPL"; -- cgit v1.2.3-59-g8ed1b