[linux-2.6-block.git] / samples / bpf / xdp_redirect_kern.c

/* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 */
#define KBUILD_MODNAME "foo"
#include <uapi/linux/bpf.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/if_vlan.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include "bpf_helpers.h"

struct bpf_map_def SEC("maps") tx_port = {
	.type = BPF_MAP_TYPE_ARRAY,
	.key_size = sizeof(int),
	.value_size = sizeof(int),
	.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),
	.value_size = sizeof(long),
	.max_entries = 1,
};

static 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_redirect")
int xdp_redirect_prog(struct xdp_md *ctx)
{
	void *data_end = (void *)(long)ctx->data_end;
	void *data = (void *)(long)ctx->data;
	struct ethhdr *eth = data;
	int rc = XDP_DROP;
	int *ifindex, port = 0;
	long *value;
	u32 key = 0;
	u64 nh_off;

	nh_off = sizeof(*eth);
	if (data + nh_off > data_end)
		return rc;

	ifindex = bpf_map_lookup_elem(&tx_port, &port);
	if (!ifindex)
		return rc;

	value = bpf_map_lookup_elem(&rxcnt, &key);
	if (value)
		*value += 1;

	swap_src_dst_mac(data);
	return bpf_redirect(*ifindex, 0);
}

/* Redirect require an XDP bpf_prog loaded on the TX device */
SEC("xdp_redirect_dummy")
int xdp_redirect_dummy_prog(struct xdp_md *ctx)
{
	return XDP_PASS;
}

char _license[] SEC("license") = "GPL";
Commit	Line	Data
832622e6 JF	1	/* Copyright (c) 2016 John Fastabend <john.r.fastabend@intel.com>
	2	*
	3	* This program is free software; you can redistribute it and/or
	4	* modify it under the terms of version 2 of the GNU General Public
	5	* License as published by the Free Software Foundation.
	6	*
	7	* This program is distributed in the hope that it will be useful, but
	8	* WITHOUT ANY WARRANTY; without even the implied warranty of
	9	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	10	* General Public License for more details.
	11	*/
	12	#define KBUILD_MODNAME "foo"
	13	#include <uapi/linux/bpf.h>
	14	#include <linux/in.h>
	15	#include <linux/if_ether.h>
	16	#include <linux/if_packet.h>
	17	#include <linux/if_vlan.h>
	18	#include <linux/ip.h>
	19	#include <linux/ipv6.h>
	20	#include "bpf_helpers.h"
	21
	22	struct bpf_map_def SEC("maps") tx_port = {
	23	.type = BPF_MAP_TYPE_ARRAY,
	24	.key_size = sizeof(int),
	25	.value_size = sizeof(int),
	26	.max_entries = 1,
	27	};
	28
306da4e6 JDB	29	/* Count RX packets, as XDP bpf_prog doesn't get direct TX-success
	30	* feedback. Redirect TX errors can be caught via a tracepoint.
	31	*/
832622e6 JF	32	struct bpf_map_def SEC("maps") rxcnt = {
	33	.type = BPF_MAP_TYPE_PERCPU_ARRAY,
	34	.key_size = sizeof(u32),
	35	.value_size = sizeof(long),
	36	.max_entries = 1,
	37	};
	38
832622e6 JF	39	static void swap_src_dst_mac(void *data)
	40	{
	41	unsigned short *p = data;
	42	unsigned short dst[3];
	43
	44	dst[0] = p[0];
	45	dst[1] = p[1];
	46	dst[2] = p[2];
	47	p[0] = p[3];
	48	p[1] = p[4];
	49	p[2] = p[5];
	50	p[3] = dst[0];
	51	p[4] = dst[1];
	52	p[5] = dst[2];
	53	}
	54
	55	SEC("xdp_redirect")
	56	int xdp_redirect_prog(struct xdp_md *ctx)
	57	{
	58	void data_end = (void )(long)ctx->data_end;
	59	void data = (void )(long)ctx->data;
	60	struct ethhdr *eth = data;
	61	int rc = XDP_DROP;
	62	int *ifindex, port = 0;
	63	long *value;
	64	u32 key = 0;
	65	u64 nh_off;
	66
	67	nh_off = sizeof(*eth);
	68	if (data + nh_off > data_end)
	69	return rc;
	70
	71	ifindex = bpf_map_lookup_elem(&tx_port, &port);
	72	if (!ifindex)
	73	return rc;
	74
	75	value = bpf_map_lookup_elem(&rxcnt, &key);
	76	if (value)
	77	*value += 1;
	78
	79	swap_src_dst_mac(data);
	80	return bpf_redirect(*ifindex, 0);
	81	}
	82
306da4e6 JDB	83	/* Redirect require an XDP bpf_prog loaded on the TX device */
306da4e6 JDB	84	SEC("xdp_redirect_dummy")
3edcf18e	85	int xdp_redirect_dummy_prog(struct xdp_md *ctx)
306da4e6 JDB	86	{
	87	return XDP_PASS;
	88	}
	89
832622e6	90	char _license[] SEC("license") = "GPL";