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 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 50 static int do_detach(int ifindex, const char *ifname, const char *app_name) 51 { 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; 56 int prog_fd; 57 int err = 1; 58 59 if (bpf_xdp_query_id(ifindex, xdp_flags, &curr_prog_id)) { 60 printf("ERROR: bpf_xdp_query_id failed (%s)\n", 61 strerror(errno)); 62 return err; 63 } 64 65 if (!curr_prog_id) { 66 printf("ERROR: flags(0x%x) xdp prog is not attached to %s\n", 67 xdp_flags, ifname); 68 return err; 69 } 70 71 info_len = sizeof(prog_info); 72 prog_fd = bpf_prog_get_fd_by_id(curr_prog_id); 73 if (prog_fd < 0) { 74 printf("ERROR: bpf_prog_get_fd_by_id failed (%s)\n", 75 strerror(errno)); 76 return prog_fd; 77 } 78 79 err = bpf_prog_get_info_by_fd(prog_fd, &prog_info, &info_len); 80 if (err) { 81 printf("ERROR: bpf_prog_get_info_by_fd failed (%s)\n", 82 strerror(errno)); 83 goto close_out; 84 } 85 snprintf(prog_name, sizeof(prog_name), "%s_prog", app_name); 86 prog_name[BPF_OBJ_NAME_LEN - 1] = '\0'; 87 88 if (strcmp(prog_info.name, prog_name)) { 89 printf("ERROR: %s isn't attached to %s\n", app_name, ifname); 90 err = 1; 91 goto close_out; 92 } 93 94 opts.old_prog_fd = prog_fd; 95 err = bpf_xdp_detach(ifindex, xdp_flags, &opts); 96 if (err < 0) 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); 101 */ 102 close_out: 103 close(prog_fd); 104 return err; 105 } 106 107 static void usage(const char *prog) 108 { 109 fprintf(stderr, 110 "usage: %s [OPTS] interface-list\n" 111 "\nOPTS:\n" 112 " -d detach program\n" 113 " -S use skb-mode\n" 114 " -F force loading prog\n" 115 " -D direct table lookups (skip fib rules)\n", 116 prog); 117 } 118 119 int main(int argc, char **argv) 120 { 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; 129 int attach = 1; 130 int ret = 0; 131 132 while ((opt = getopt(argc, argv, ":dDSF")) != -1) { 133 switch (opt) { 134 case 'd': 135 attach = 0; 136 break; 137 case 'S': 138 xdp_flags |= XDP_FLAGS_SKB_MODE; 139 break; 140 case 'F': 141 xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST; 142 break; 143 case 'D': 144 prog_name = "xdp_fwd_direct"; 145 break; 146 default: 147 usage(basename(argv[0])); 148 return 1; 149 } 150 } 151 152 if (!(xdp_flags & XDP_FLAGS_SKB_MODE)) 153 xdp_flags |= XDP_FLAGS_DRV_MODE; 154 155 if (optind == argc) { 156 usage(basename(argv[0])); 157 return 1; 158 } 159 160 if (attach) { 161 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 162 163 if (access(filename, O_RDONLY) < 0) { 164 printf("error accessing file %s: %s\n", 165 filename, strerror(errno)); 166 return 1; 167 } 168 169 obj = bpf_object__open_file(filename, NULL); 170 if (libbpf_get_error(obj)) 171 return 1; 172 173 prog = bpf_object__next_program(obj, NULL); 174 bpf_program__set_type(prog, BPF_PROG_TYPE_XDP); 175 176 err = bpf_object__load(obj); 177 if (err) { 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" 181 */ 182 return 1; 183 } 184 185 bpf_object__for_each_program(pos, obj) { 186 sec_name = bpf_program__section_name(pos); 187 if (sec_name && !strcmp(sec_name, prog_name)) { 188 prog = pos; 189 break; 190 } 191 } 192 prog_fd = bpf_program__fd(prog); 193 if (prog_fd < 0) { 194 printf("program not found: %s\n", strerror(prog_fd)); 195 return 1; 196 } 197 map_fd = bpf_map__fd(bpf_object__find_map_by_name(obj, 198 "xdp_tx_ports")); 199 if (map_fd < 0) { 200 printf("map not found: %s\n", strerror(map_fd)); 201 return 1; 202 } 203 } 204 205 for (i = optind; i < argc; ++i) { 206 idx = if_nametoindex(argv[i]); 207 if (!idx) 208 idx = strtoul(argv[i], NULL, 0); 209 210 if (!idx) { 211 fprintf(stderr, "Invalid arg\n"); 212 return 1; 213 } 214 if (!attach) { 215 err = do_detach(idx, argv[i], prog_name); 216 if (err) 217 ret = err; 218 } else { 219 err = do_attach(idx, prog_fd, map_fd, argv[i]); 220 if (err) 221 ret = err; 222 } 223 } 224 225 return ret; 226 } 227