1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
/* 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_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";
|
