1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2017-18 David Ahern <dsahern@gmail.com>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 */
13
14 #include <linux/bpf.h>
15 #include <linux/if_link.h>
16 #include <linux/limits.h>
17 #include <net/if.h>
18 #include <errno.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <stdbool.h>
22 #include <string.h>
23 #include <unistd.h>
24 #include <fcntl.h>
25 #include <libgen.h>
26
27 #include <bpf/libbpf.h>
28 #include <bpf/bpf.h>
29
30 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
31
do_attach(int idx,int prog_fd,int map_fd,const char * name)32 static int do_attach(int idx, int prog_fd, int map_fd, const char *name)
33 {
34 int err;
35
36 err = bpf_xdp_attach(idx, prog_fd, xdp_flags, NULL);
37 if (err < 0) {
38 printf("ERROR: failed to attach program to %s\n", name);
39 return err;
40 }
41
42 /* Adding ifindex as a possible egress TX port */
43 err = bpf_map_update_elem(map_fd, &idx, &idx, 0);
44 if (err)
45 printf("ERROR: failed using device %s as TX-port\n", name);
46
47 return err;
48 }
49
do_detach(int idx,const char * name)50 static int do_detach(int idx, const char *name)
51 {
52 int err;
53
54 err = bpf_xdp_detach(idx, xdp_flags, NULL);
55 if (err < 0)
56 printf("ERROR: failed to detach program from %s\n", name);
57
58 /* TODO: Remember to cleanup map, when adding use of shared map
59 * bpf_map_delete_elem((map_fd, &idx);
60 */
61 return err;
62 }
63
usage(const char * prog)64 static void usage(const char *prog)
65 {
66 fprintf(stderr,
67 "usage: %s [OPTS] interface-list\n"
68 "\nOPTS:\n"
69 " -d detach program\n"
70 " -S use skb-mode\n"
71 " -F force loading prog\n"
72 " -D direct table lookups (skip fib rules)\n",
73 prog);
74 }
75
main(int argc,char ** argv)76 int main(int argc, char **argv)
77 {
78 const char *prog_name = "xdp_fwd";
79 struct bpf_program *prog = NULL;
80 struct bpf_program *pos;
81 const char *sec_name;
82 int prog_fd = -1, map_fd = -1;
83 char filename[PATH_MAX];
84 struct bpf_object *obj;
85 int opt, i, idx, err;
86 int attach = 1;
87 int ret = 0;
88
89 while ((opt = getopt(argc, argv, ":dDSF")) != -1) {
90 switch (opt) {
91 case 'd':
92 attach = 0;
93 break;
94 case 'S':
95 xdp_flags |= XDP_FLAGS_SKB_MODE;
96 break;
97 case 'F':
98 xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
99 break;
100 case 'D':
101 prog_name = "xdp_fwd_direct";
102 break;
103 default:
104 usage(basename(argv[0]));
105 return 1;
106 }
107 }
108
109 if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
110 xdp_flags |= XDP_FLAGS_DRV_MODE;
111
112 if (optind == argc) {
113 usage(basename(argv[0]));
114 return 1;
115 }
116
117 if (attach) {
118 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
119
120 if (access(filename, O_RDONLY) < 0) {
121 printf("error accessing file %s: %s\n",
122 filename, strerror(errno));
123 return 1;
124 }
125
126 obj = bpf_object__open_file(filename, NULL);
127 if (libbpf_get_error(obj))
128 return 1;
129
130 prog = bpf_object__next_program(obj, NULL);
131 bpf_program__set_type(prog, BPF_PROG_TYPE_XDP);
132
133 err = bpf_object__load(obj);
134 if (err) {
135 printf("Does kernel support devmap lookup?\n");
136 /* If not, the error message will be:
137 * "cannot pass map_type 14 into func bpf_map_lookup_elem#1"
138 */
139 return 1;
140 }
141
142 bpf_object__for_each_program(pos, obj) {
143 sec_name = bpf_program__section_name(pos);
144 if (sec_name && !strcmp(sec_name, prog_name)) {
145 prog = pos;
146 break;
147 }
148 }
149 prog_fd = bpf_program__fd(prog);
150 if (prog_fd < 0) {
151 printf("program not found: %s\n", strerror(prog_fd));
152 return 1;
153 }
154 map_fd = bpf_map__fd(bpf_object__find_map_by_name(obj,
155 "xdp_tx_ports"));
156 if (map_fd < 0) {
157 printf("map not found: %s\n", strerror(map_fd));
158 return 1;
159 }
160 }
161
162 for (i = optind; i < argc; ++i) {
163 idx = if_nametoindex(argv[i]);
164 if (!idx)
165 idx = strtoul(argv[i], NULL, 0);
166
167 if (!idx) {
168 fprintf(stderr, "Invalid arg\n");
169 return 1;
170 }
171 if (!attach) {
172 err = do_detach(idx, argv[i]);
173 if (err)
174 ret = err;
175 } else {
176 err = do_attach(idx, prog_fd, map_fd, argv[i]);
177 if (err)
178 ret = err;
179 }
180 }
181
182 return ret;
183 }
184