1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2017-18 David Ahern <dsahern@gmail.com>
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.
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.
14 #include <linux/bpf.h>
15 #include <linux/if_link.h>
16 #include <linux/limits.h>
27 #include <bpf/libbpf.h>
30 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
32 static int do_attach(int idx, int prog_fd, int map_fd, const char *name)
36 err = bpf_xdp_attach(idx, prog_fd, xdp_flags, NULL);
38 printf("ERROR: failed to attach program to %s\n", name);
42 /* Adding ifindex as a possible egress TX port */
43 err = bpf_map_update_elem(map_fd, &idx, &idx, 0);
45 printf("ERROR: failed using device %s as TX-port\n", name);
50 static int do_detach(int ifindex, const char *ifname, const char *app_name)
52 LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
53 struct bpf_prog_info prog_info = {};
54 char prog_name[BPF_OBJ_NAME_LEN];
55 __u32 info_len, curr_prog_id;
59 if (bpf_xdp_query_id(ifindex, xdp_flags, &curr_prog_id)) {
60 printf("ERROR: bpf_xdp_query_id failed (%s)\n",
66 printf("ERROR: flags(0x%x) xdp prog is not attached to %s\n",
71 info_len = sizeof(prog_info);
72 prog_fd = bpf_prog_get_fd_by_id(curr_prog_id);
74 printf("ERROR: bpf_prog_get_fd_by_id failed (%s)\n",
79 err = bpf_prog_get_info_by_fd(prog_fd, &prog_info, &info_len);
81 printf("ERROR: bpf_prog_get_info_by_fd failed (%s)\n",
85 snprintf(prog_name, sizeof(prog_name), "%s_prog", app_name);
86 prog_name[BPF_OBJ_NAME_LEN - 1] = '\0';
88 if (strcmp(prog_info.name, prog_name)) {
89 printf("ERROR: %s isn't attached to %s\n", app_name, ifname);
94 opts.old_prog_fd = prog_fd;
95 err = bpf_xdp_detach(ifindex, xdp_flags, &opts);
97 printf("ERROR: failed to detach program from %s (%s)\n",
98 ifname, strerror(errno));
99 /* TODO: Remember to cleanup map, when adding use of shared map
100 * bpf_map_delete_elem((map_fd, &idx);
107 static void usage(const char *prog)
110 "usage: %s [OPTS] interface-list\n"
112 " -d detach program\n"
114 " -F force loading prog\n"
115 " -D direct table lookups (skip fib rules)\n",
119 int main(int argc, char **argv)
121 const char *prog_name = "xdp_fwd";
122 struct bpf_program *prog = NULL;
123 struct bpf_program *pos;
124 const char *sec_name;
125 int prog_fd = -1, map_fd = -1;
126 char filename[PATH_MAX];
127 struct bpf_object *obj;
128 int opt, i, idx, err;
132 while ((opt = getopt(argc, argv, ":dDSF")) != -1) {
138 xdp_flags |= XDP_FLAGS_SKB_MODE;
141 xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
144 prog_name = "xdp_fwd_direct";
147 usage(basename(argv[0]));
152 if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
153 xdp_flags |= XDP_FLAGS_DRV_MODE;
155 if (optind == argc) {
156 usage(basename(argv[0]));
161 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
163 if (access(filename, O_RDONLY) < 0) {
164 printf("error accessing file %s: %s\n",
165 filename, strerror(errno));
169 obj = bpf_object__open_file(filename, NULL);
170 if (libbpf_get_error(obj))
173 prog = bpf_object__next_program(obj, NULL);
174 bpf_program__set_type(prog, BPF_PROG_TYPE_XDP);
176 err = bpf_object__load(obj);
178 printf("Does kernel support devmap lookup?\n");
179 /* If not, the error message will be:
180 * "cannot pass map_type 14 into func bpf_map_lookup_elem#1"
185 bpf_object__for_each_program(pos, obj) {
186 sec_name = bpf_program__section_name(pos);
187 if (sec_name && !strcmp(sec_name, prog_name)) {
192 prog_fd = bpf_program__fd(prog);
194 printf("program not found: %s\n", strerror(prog_fd));
197 map_fd = bpf_map__fd(bpf_object__find_map_by_name(obj,
200 printf("map not found: %s\n", strerror(map_fd));
205 for (i = optind; i < argc; ++i) {
206 idx = if_nametoindex(argv[i]);
208 idx = strtoul(argv[i], NULL, 0);
211 fprintf(stderr, "Invalid arg\n");
215 err = do_detach(idx, argv[i], prog_name);
219 err = do_attach(idx, prog_fd, map_fd, argv[i]);