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/* 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";
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