[linux-block.git] / samples / bpf / xdp_rxq_info_kern.c

/* SPDX-License-Identifier: GPL-2.0
 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
 *
 *  Example howto extract XDP RX-queue info
 */
#include <uapi/linux/bpf.h>
#include <uapi/linux/if_ether.h>
#include <uapi/linux/in.h>
#include <bpf/bpf_helpers.h>

/* Config setup from with userspace
 *
 * User-side setup ifindex in config_map, to verify that
 * ctx->ingress_ifindex is correct (against configured ifindex)
 */
struct config {
	__u32 action;
	int ifindex;
	__u32 options;
};
enum cfg_options_flags {
	NO_TOUCH = 0x0U,
	READ_MEM = 0x1U,
	SWAP_MAC = 0x2U,
};

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__type(key, int);
	__type(value, struct config);
	__uint(max_entries, 1);
} config_map SEC(".maps");

/* Common stats data record (shared with userspace) */
struct datarec {
	__u64 processed;
	__u64 issue;
};

struct {
	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
	__type(key, u32);
	__type(value, struct datarec);
	__uint(max_entries, 1);
} stats_global_map SEC(".maps");

#define MAX_RXQs 64

/* Stats per rx_queue_index (per CPU) */
struct {
	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
	__type(key, u32);
	__type(value, struct datarec);
	__uint(max_entries, MAX_RXQs + 1);
} rx_queue_index_map SEC(".maps");

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)
{
	void *data_end = (void *)(long)ctx->data_end;
	void *data     = (void *)(long)ctx->data;
	struct datarec *rec, *rxq_rec;
	int ingress_ifindex;
	struct config *config;
	u32 key = 0;

	/* Global stats record */
	rec = bpf_map_lookup_elem(&stats_global_map, &key);
	if (!rec)
		return XDP_ABORTED;
	rec->processed++;

	/* Accessing ctx->ingress_ifindex, cause BPF to rewrite BPF
	 * instructions inside kernel to access xdp_rxq->dev->ifindex
	 */
	ingress_ifindex = ctx->ingress_ifindex;

	config = bpf_map_lookup_elem(&config_map, &key);
	if (!config)
		return XDP_ABORTED;

	/* Simple test: check ctx provided ifindex is as expected */
	if (ingress_ifindex != config->ifindex) {
		/* count this error case */
		rec->issue++;
		return XDP_ABORTED;
	}

	/* Update stats per rx_queue_index. Handle if rx_queue_index
	 * is larger than stats map can contain info for.
	 */
	key = ctx->rx_queue_index;
	if (key >= MAX_RXQs)
		key = MAX_RXQs;
	rxq_rec = bpf_map_lookup_elem(&rx_queue_index_map, &key);
	if (!rxq_rec)
		return XDP_ABORTED;
	rxq_rec->processed++;
	if (key == MAX_RXQs)
		rxq_rec->issue++;

	/* Default: Don't touch packet data, only count packets */
	if (unlikely(config->options & (READ_MEM|SWAP_MAC))) {
		struct ethhdr *eth = data;

		if (eth + 1 > data_end)
			return XDP_ABORTED;

		/* 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;
}

char _license[] SEC("license") = "GPL";
Commit	Line	Data
0fca931a JDB	1	/* SPDX-License-Identifier: GPL-2.0
	2	* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
	3	*
	4	* Example howto extract XDP RX-queue info
	5	*/
	6	#include <uapi/linux/bpf.h>
0d25c43a JDB	7	#include <uapi/linux/if_ether.h>
0d25c43a JDB	8	#include <uapi/linux/in.h>
7cf245a3	9	#include <bpf/bpf_helpers.h>
0fca931a JDB	10
	11	/* Config setup from with userspace
	12	*
	13	* User-side setup ifindex in config_map, to verify that
	14	* ctx->ingress_ifindex is correct (against configured ifindex)
	15	*/
	16	struct config {
	17	__u32 action;
	18	int ifindex;
0d25c43a JDB	19	__u32 options;
	20	};
	21	enum cfg_options_flags {
	22	NO_TOUCH = 0x0U,
	23	READ_MEM = 0x1U,
509fda10	24	SWAP_MAC = 0x2U,
0fca931a	25	};
451d1dc8 DL	26
	27	struct {
	28	__uint(type, BPF_MAP_TYPE_ARRAY);
	29	__type(key, int);
	30	__type(value, struct config);
	31	__uint(max_entries, 1);
	32	} config_map SEC(".maps");
0fca931a JDB	33
	34	/* Common stats data record (shared with userspace) */
	35	struct datarec {
	36	__u64 processed;
	37	__u64 issue;
	38	};
	39
451d1dc8 DL	40	struct {
	41	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
	42	__type(key, u32);
	43	__type(value, struct datarec);
	44	__uint(max_entries, 1);
	45	} stats_global_map SEC(".maps");
0fca931a JDB	46
	47	#define MAX_RXQs 64
	48
	49	/* Stats per rx_queue_index (per CPU) */
451d1dc8 DL	50	struct {
	51	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
	52	__type(key, u32);
	53	__type(value, struct datarec);
	54	__uint(max_entries, MAX_RXQs + 1);
	55	} rx_queue_index_map SEC(".maps");
0fca931a	56
509fda10 JDB	57	static __always_inline
	58	void swap_src_dst_mac(void *data)
	59	{
	60	unsigned short *p = data;
	61	unsigned short dst[3];
	62
	63	dst[0] = p[0];
	64	dst[1] = p[1];
	65	dst[2] = p[2];
	66	p[0] = p[3];
	67	p[1] = p[4];
	68	p[2] = p[5];
	69	p[3] = dst[0];
	70	p[4] = dst[1];
	71	p[5] = dst[2];
	72	}
	73
0fca931a JDB	74	SEC("xdp_prog0")
	75	int xdp_prognum0(struct xdp_md *ctx)
	76	{
	77	void data_end = (void )(long)ctx->data_end;
	78	void data = (void )(long)ctx->data;
	79	struct datarec rec, rxq_rec;
	80	int ingress_ifindex;
	81	struct config *config;
	82	u32 key = 0;
	83
	84	/* Global stats record */
	85	rec = bpf_map_lookup_elem(&stats_global_map, &key);
	86	if (!rec)
	87	return XDP_ABORTED;
	88	rec->processed++;
	89
	90	/* Accessing ctx->ingress_ifindex, cause BPF to rewrite BPF
	91	* instructions inside kernel to access xdp_rxq->dev->ifindex
	92	*/
	93	ingress_ifindex = ctx->ingress_ifindex;
	94
	95	config = bpf_map_lookup_elem(&config_map, &key);
	96	if (!config)
	97	return XDP_ABORTED;
	98
	99	/* Simple test: check ctx provided ifindex is as expected */
	100	if (ingress_ifindex != config->ifindex) {
	101	/* count this error case */
	102	rec->issue++;
	103	return XDP_ABORTED;
	104	}
	105
	106	/* Update stats per rx_queue_index. Handle if rx_queue_index
	107	* is larger than stats map can contain info for.
	108	*/
	109	key = ctx->rx_queue_index;
	110	if (key >= MAX_RXQs)
	111	key = MAX_RXQs;
	112	rxq_rec = bpf_map_lookup_elem(&rx_queue_index_map, &key);
	113	if (!rxq_rec)
	114	return XDP_ABORTED;
	115	rxq_rec->processed++;
	116	if (key == MAX_RXQs)
	117	rxq_rec->issue++;
	118
0d25c43a	119	/* Default: Don't touch packet data, only count packets */
509fda10	120	if (unlikely(config->options & (READ_MEM\|SWAP_MAC))) {
0d25c43a JDB	121	struct ethhdr *eth = data;
	122
	123	if (eth + 1 > data_end)
	124	return XDP_ABORTED;
	125
	126	/* Avoid compiler removing this: Drop non 802.3 Ethertypes */
	127	if (ntohs(eth->h_proto) < ETH_P_802_3_MIN)
	128	return XDP_ABORTED;
509fda10 JDB	129
	130	/* XDP_TX requires changing MAC-addrs, else HW may drop.
	131	* Can also be enabled with --swapmac (for test purposes)
	132	*/
	133	if (unlikely(config->options & SWAP_MAC))
	134	swap_src_dst_mac(data);
0d25c43a JDB	135	}
0d25c43a JDB	136
0fca931a JDB	137	return config->action;
	138	}
	139
	140	char _license[] SEC("license") = "GPL";