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 "libbpf.h" 28 #include <bpf/bpf.h> 29 30 static int do_attach(int idx, int prog_fd, int map_fd, const char *name) 31 { 32 int err; 33 34 err = bpf_set_link_xdp_fd(idx, prog_fd, 0); 35 if (err < 0) { 36 printf("ERROR: failed to attach program to %s\n", name); 37 return err; 38 } 39 40 /* Adding ifindex as a possible egress TX port */ 41 err = bpf_map_update_elem(map_fd, &idx, &idx, 0); 42 if (err) 43 printf("ERROR: failed using device %s as TX-port\n", name); 44 45 return err; 46 } 47 48 static int do_detach(int idx, const char *name) 49 { 50 int err; 51 52 err = bpf_set_link_xdp_fd(idx, -1, 0); 53 if (err < 0) 54 printf("ERROR: failed to detach program from %s\n", name); 55 56 /* TODO: Remember to cleanup map, when adding use of shared map 57 * bpf_map_delete_elem((map_fd, &idx); 58 */ 59 return err; 60 } 61 62 static void usage(const char *prog) 63 { 64 fprintf(stderr, 65 "usage: %s [OPTS] interface-list\n" 66 "\nOPTS:\n" 67 " -d detach program\n" 68 " -D direct table lookups (skip fib rules)\n", 69 prog); 70 } 71 72 int main(int argc, char **argv) 73 { 74 struct bpf_prog_load_attr prog_load_attr = { 75 .prog_type = BPF_PROG_TYPE_XDP, 76 }; 77 const char *prog_name = "xdp_fwd"; 78 struct bpf_program *prog; 79 int prog_fd, map_fd = -1; 80 char filename[PATH_MAX]; 81 struct bpf_object *obj; 82 int opt, i, idx, err; 83 int attach = 1; 84 int ret = 0; 85 86 while ((opt = getopt(argc, argv, ":dD")) != -1) { 87 switch (opt) { 88 case 'd': 89 attach = 0; 90 break; 91 case 'D': 92 prog_name = "xdp_fwd_direct"; 93 break; 94 default: 95 usage(basename(argv[0])); 96 return 1; 97 } 98 } 99 100 if (optind == argc) { 101 usage(basename(argv[0])); 102 return 1; 103 } 104 105 if (attach) { 106 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 107 prog_load_attr.file = filename; 108 109 if (access(filename, O_RDONLY) < 0) { 110 printf("error accessing file %s: %s\n", 111 filename, strerror(errno)); 112 return 1; 113 } 114 115 err = bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd); 116 if (err) { 117 printf("Does kernel support devmap lookup?\n"); 118 /* If not, the error message will be: 119 * "cannot pass map_type 14 into func bpf_map_lookup_elem#1" 120 */ 121 return 1; 122 } 123 124 prog = bpf_object__find_program_by_title(obj, prog_name); 125 prog_fd = bpf_program__fd(prog); 126 if (prog_fd < 0) { 127 printf("program not found: %s\n", strerror(prog_fd)); 128 return 1; 129 } 130 map_fd = bpf_map__fd(bpf_object__find_map_by_name(obj, 131 "xdp_tx_ports")); 132 if (map_fd < 0) { 133 printf("map not found: %s\n", strerror(map_fd)); 134 return 1; 135 } 136 } 137 138 for (i = optind; i < argc; ++i) { 139 idx = if_nametoindex(argv[i]); 140 if (!idx) 141 idx = strtoul(argv[i], NULL, 0); 142 143 if (!idx) { 144 fprintf(stderr, "Invalid arg\n"); 145 return 1; 146 } 147 if (!attach) { 148 err = do_detach(idx, argv[i]); 149 if (err) 150 ret = err; 151 } else { 152 err = do_attach(idx, prog_fd, map_fd, argv[i]); 153 if (err) 154 ret = err; 155 } 156 } 157 158 return ret; 159 } 160