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_user.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) (limited to 'samples/bpf/xdp_redirect_user.c') diff --git a/samples/bpf/xdp_redirect_user.c b/samples/bpf/xdp_redirect_user.c index f705a1905d2d..4475d837bf2c 100644 --- a/samples/bpf/xdp_redirect_user.c +++ b/samples/bpf/xdp_redirect_user.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -26,17 +27,18 @@ static int ifindex_in; static int ifindex_out; +static bool ifindex_out_xdp_dummy_attached = true; static __u32 xdp_flags; static void int_exit(int sig) { set_link_xdp_fd(ifindex_in, -1, xdp_flags); + if (ifindex_out_xdp_dummy_attached) + set_link_xdp_fd(ifindex_out, -1, xdp_flags); exit(0); } -/* simple per-protocol drop counter - */ static void poll_stats(int interval, int ifindex) { unsigned int nr_cpus = bpf_num_possible_cpus(); @@ -112,14 +114,21 @@ int main(int argc, char **argv) return 1; } - signal(SIGINT, int_exit); - signal(SIGTERM, int_exit); - if (set_link_xdp_fd(ifindex_in, prog_fd[0], xdp_flags) < 0) { - printf("link set xdp fd failed\n"); + printf("ERROR: link set xdp fd failed on %d\n", ifindex_in); return 1; } + /* Loading dummy XDP prog on out-device */ + if (set_link_xdp_fd(ifindex_out, prog_fd[1], + (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) { + printf("WARN: link set xdp fd failed on %d\n", ifindex_out); + ifindex_out_xdp_dummy_attached = false; + } + + signal(SIGINT, int_exit); + signal(SIGTERM, int_exit); + /* bpf redirect port */ ret = bpf_map_update_elem(map_fd[0], &key, &ifindex_out, 0); if (ret) { -- cgit v1.2.3-59-g8ed1b