Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 509fda10 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by Daniel Borkmann
Browse files

samples/bpf: xdp_rxq_info action XDP_TX must adjust MAC-addrs 



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: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarToke Høiland-Jørgensen <toke@toke.dk>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 0d25c43a

samples/bpf/xdp_rxq_info_kern.c

+25 −1
Original line number Diff line number Diff line
@@ -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;

samples/bpf/xdp_rxq_info_user.c

+11 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ static const struct option long_options[] = { 
	{"no-separators", no_argument,		NULL, 'z' },

	{"action",	required_argument,	NULL, 'a' },

	{"readmem", 	no_argument,		NULL, 'r' },

	{"swapmac", 	no_argument,		NULL, 'm' },

	{0, 0, NULL,  0 }

};
@@ -72,6 +73,7 @@ struct config { 
enum cfg_options_flags {

	NO_TOUCH = 0x0U,

	READ_MEM = 0x1U,

	SWAP_MAC = 0x2U,

};

#define XDP_ACTION_MAX (XDP_TX + 1)

#define XDP_ACTION_MAX_STRLEN 11
@@ -119,6 +121,8 @@ static char* options2str(enum cfg_options_flags flag) 
{

	if (flag == NO_TOUCH)

		return "no_touch";

	if (flag & SWAP_MAC)

		return "swapmac";

	if (flag & READ_MEM)

		return "read";

	fprintf(stderr, "ERR: Unknown config option flags");
@@ -517,6 +521,9 @@ int main(int argc, char **argv) 
		case 'r':

			cfg_options |= READ_MEM;

			break;

		case 'm':

			cfg_options |= SWAP_MAC;

			break;

		case 'h':

		error:

		default:
@@ -543,6 +550,10 @@ int main(int argc, char **argv) 
		}

	}

	cfg.action = action;



	/* XDP_TX requires changing MAC-addrs, else HW may drop */

	if (action == XDP_TX)

		cfg_options |= SWAP_MAC;

	cfg.options = cfg_options;



	/* Trick to pretty printf with thousands separators use %' */