From 509fda105ba8f9a1a5c6f8b79e4c7fc50b35c1e3 Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Mon, 25 Jun 2018 16:27:48 +0200 Subject: samples/bpf: xdp_rxq_info action XDP_TX must adjust MAC-addrs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit XDP_TX requires also changing the MAC-addrs, else some hardware may drop the TX packet before reaching the wire. This was observed with driver mlx5. If xdp_rxq_info select --action XDP_TX the swapmac functionality is activated. It is also possible to manually enable via cmdline option --swapmac. This is practical if wanting to measure the overhead of writing/updating payload for other action types. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Toke Høiland-Jørgensen Acked-by: Song Liu Signed-off-by: Daniel Borkmann --- samples/bpf/xdp_rxq_info_kern.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) (limited to 'samples/bpf/xdp_rxq_info_kern.c') diff --git a/samples/bpf/xdp_rxq_info_kern.c b/samples/bpf/xdp_rxq_info_kern.c index 61af6210df2f..222a83eed1cb 100644 --- a/samples/bpf/xdp_rxq_info_kern.c +++ b/samples/bpf/xdp_rxq_info_kern.c @@ -21,6 +21,7 @@ struct config { enum cfg_options_flags { NO_TOUCH = 0x0U, READ_MEM = 0x1U, + SWAP_MAC = 0x2U, }; struct bpf_map_def SEC("maps") config_map = { .type = BPF_MAP_TYPE_ARRAY, @@ -52,6 +53,23 @@ struct bpf_map_def SEC("maps") rx_queue_index_map = { .max_entries = MAX_RXQs + 1, }; +static __always_inline +void swap_src_dst_mac(void *data) +{ + unsigned short *p = data; + unsigned short dst[3]; + + dst[0] = p[0]; + dst[1] = p[1]; + dst[2] = p[2]; + p[0] = p[3]; + p[1] = p[4]; + p[2] = p[5]; + p[3] = dst[0]; + p[4] = dst[1]; + p[5] = dst[2]; +} + SEC("xdp_prog0") int xdp_prognum0(struct xdp_md *ctx) { @@ -98,7 +116,7 @@ int xdp_prognum0(struct xdp_md *ctx) rxq_rec->issue++; /* Default: Don't touch packet data, only count packets */ - if (unlikely(config->options & READ_MEM)) { + if (unlikely(config->options & (READ_MEM|SWAP_MAC))) { struct ethhdr *eth = data; if (eth + 1 > data_end) @@ -107,6 +125,12 @@ int xdp_prognum0(struct xdp_md *ctx) /* Avoid compiler removing this: Drop non 802.3 Ethertypes */ if (ntohs(eth->h_proto) < ETH_P_802_3_MIN) return XDP_ABORTED; + + /* XDP_TX requires changing MAC-addrs, else HW may drop. + * Can also be enabled with --swapmac (for test purposes) + */ + if (unlikely(config->options & SWAP_MAC)) + swap_src_dst_mac(data); } return config->action; -- cgit v1.2.3