// SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2017-18 David Ahern <dsahern@gmail.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #include <linux/bpf.h> #include <linux/if_link.h> #include <linux/limits.h> #include <net/if.h> #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <string.h> #include <unistd.h> #include <fcntl.h> #include <libgen.h> #include <bpf/libbpf.h> #include <bpf/bpf.h> static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST; static int do_attach(int idx, int prog_fd, int map_fd, const char *name) { int err; err = bpf_set_link_xdp_fd(idx, prog_fd, xdp_flags); if (err < 0) { printf("ERROR: failed to attach program to %s\n", name); return err; } /* Adding ifindex as a possible egress TX port */ err = bpf_map_update_elem(map_fd, &idx, &idx, 0); if (err) printf("ERROR: failed using device %s as TX-port\n", name); return err; } static int do_detach(int idx, const char *name) { int err; err = bpf_set_link_xdp_fd(idx, -1, xdp_flags); if (err < 0) printf("ERROR: failed to detach program from %s\n", name); /* TODO: Remember to cleanup map, when adding use of shared map * bpf_map_delete_elem((map_fd, &idx); */ return err; } static void usage(const char *prog) { fprintf(stderr, "usage: %s [OPTS] interface-list\n" "\nOPTS:\n" " -d detach program\n" " -D direct table lookups (skip fib rules)\n", prog); } int main(int argc, char **argv) { struct bpf_prog_load_attr prog_load_attr = { .prog_type = BPF_PROG_TYPE_XDP, }; const char *prog_name = "xdp_fwd"; struct bpf_program *prog; int prog_fd, map_fd = -1; char filename[PATH_MAX]; struct bpf_object *obj; int opt, i, idx, err; int attach = 1; int ret = 0; while ((opt = getopt(argc, argv, ":dDSF")) != -1) { switch (opt) { case 'd': attach = 0; break; case 'S': xdp_flags |= XDP_FLAGS_SKB_MODE; break; case 'F': xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST; break; case 'D': prog_name = "xdp_fwd_direct"; break; default: usage(basename(argv[0])); return 1; } } if (!(xdp_flags & XDP_FLAGS_SKB_MODE)) xdp_flags |= XDP_FLAGS_DRV_MODE; if (optind == argc) { usage(basename(argv[0])); return 1; } if (attach) { snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); prog_load_attr.file = filename; if (access(filename, O_RDONLY) < 0) { printf("error accessing file %s: %s\n", filename, strerror(errno)); return 1; } err = bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd); if (err) { printf("Does kernel support devmap lookup?\n"); /* If not, the error message will be: * "cannot pass map_type 14 into func bpf_map_lookup_elem#1" */ return 1; } prog = bpf_object__find_program_by_title(obj, prog_name); prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { printf("program not found: %s\n", strerror(prog_fd)); return 1; } map_fd = bpf_map__fd(bpf_object__find_map_by_name(obj, "xdp_tx_ports")); if (map_fd < 0) { printf("map not found: %s\n", strerror(map_fd)); return 1; } } for (i = optind; i < argc; ++i) { idx = if_nametoindex(argv[i]); if (!idx) idx = strtoul(argv[i], NULL, 0); if (!idx) { fprintf(stderr, "Invalid arg\n"); return 1; } if (!attach) { err = do_detach(idx, argv[i]); if (err) ret = err; } else { err = do_attach(idx, prog_fd, map_fd, argv[i]); if (err) ret = err; } } return ret; }