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1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2017-18 David Ahern <dsahern@gmail.com>3 *4 * This program is free software; you can redistribute it and/or5 * modify it under the terms of version 2 of the GNU General Public6 * License as published by the Free Software Foundation.7 *8 * This program is distributed in the hope that it will be useful, but9 * WITHOUT ANY WARRANTY; without even the implied warranty of10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU11 * 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 30static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;31 32static 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 50static 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 map100 * bpf_map_delete_elem((map_fd, &idx);101 */102close_out:103 close(prog_fd);104 return err;105}106 107static 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 119int 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