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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2017-18 David Ahern <dsahern@gmail.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.
*/
#include <linux/bpf.h>
#include <linux/if_link.h>
#include <linux/limits.h>
#include <net/if.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <libgen.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static int do_attach(int idx, int prog_fd, int map_fd, const char *name)
{
int err;
err = bpf_set_link_xdp_fd(idx, prog_fd, xdp_flags);
if (err < 0) {
printf("ERROR: failed to attach program to %s\n", name);
return err;
}
/* Adding ifindex as a possible egress TX port */
err = bpf_map_update_elem(map_fd, &idx, &idx, 0);
if (err)
printf("ERROR: failed using device %s as TX-port\n", name);
return err;
}
static int do_detach(int idx, const char *name)
{
int err;
err = bpf_set_link_xdp_fd(idx, -1, xdp_flags);
if (err < 0)
printf("ERROR: failed to detach program from %s\n", name);
/* TODO: Remember to cleanup map, when adding use of shared map
* bpf_map_delete_elem((map_fd, &idx);
*/
return err;
}
static void usage(const char *prog)
{
fprintf(stderr,
"usage: %s [OPTS] interface-list\n"
"\nOPTS:\n"
" -d detach program\n"
" -S use skb-mode\n"
" -F force loading prog\n"
" -D direct table lookups (skip fib rules)\n",
prog);
}
int main(int argc, char **argv)
{
struct bpf_prog_load_attr prog_load_attr = {
.prog_type = BPF_PROG_TYPE_XDP,
};
const char *prog_name = "xdp_fwd";
struct bpf_program *prog = NULL;
struct bpf_program *pos;
const char *sec_name;
int prog_fd, map_fd = -1;
char filename[PATH_MAX];
struct bpf_object *obj;
int opt, i, idx, err;
int attach = 1;
int ret = 0;
while ((opt = getopt(argc, argv, ":dDSF")) != -1) {
switch (opt) {
case 'd':
attach = 0;
break;
case 'S':
xdp_flags |= XDP_FLAGS_SKB_MODE;
break;
case 'F':
xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
break;
case 'D':
prog_name = "xdp_fwd_direct";
break;
default:
usage(basename(argv[0]));
return 1;
}
}
if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
xdp_flags |= XDP_FLAGS_DRV_MODE;
if (optind == argc) {
usage(basename(argv[0]));
return 1;
}
if (attach) {
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
prog_load_attr.file = filename;
if (access(filename, O_RDONLY) < 0) {
printf("error accessing file %s: %s\n",
filename, strerror(errno));
return 1;
}
err = bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd);
if (err) {
printf("Does kernel support devmap lookup?\n");
/* If not, the error message will be:
* "cannot pass map_type 14 into func bpf_map_lookup_elem#1"
*/
return 1;
}
bpf_object__for_each_program(pos, obj) {
sec_name = bpf_program__section_name(pos);
if (sec_name && !strcmp(sec_name, prog_name)) {
prog = pos;
break;
}
}
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
printf("program not found: %s\n", strerror(prog_fd));
return 1;
}
map_fd = bpf_map__fd(bpf_object__find_map_by_name(obj,
"xdp_tx_ports"));
if (map_fd < 0) {
printf("map not found: %s\n", strerror(map_fd));
return 1;
}
}
for (i = optind; i < argc; ++i) {
idx = if_nametoindex(argv[i]);
if (!idx)
idx = strtoul(argv[i], NULL, 0);
if (!idx) {
fprintf(stderr, "Invalid arg\n");
return 1;
}
if (!attach) {
err = do_detach(idx, argv[i]);
if (err)
ret = err;
} else {
err = do_attach(idx, prog_fd, map_fd, argv[i]);
if (err)
ret = err;
}
}
return ret;
}
|
