diff options
Diffstat (limited to 'samples/bpf/xdp_fwd_user.c')
| -rw-r--r-- | samples/bpf/xdp_fwd_user.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/samples/bpf/xdp_fwd_user.c b/samples/bpf/xdp_fwd_user.c new file mode 100644 index 000000000..84f57f120 --- /dev/null +++ b/samples/bpf/xdp_fwd_user.c @@ -0,0 +1,226 @@ +// 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_xdp_attach(idx, prog_fd, xdp_flags, NULL); + 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 ifindex, const char *ifname, const char *app_name) +{ + LIBBPF_OPTS(bpf_xdp_attach_opts, opts); + struct bpf_prog_info prog_info = {}; + char prog_name[BPF_OBJ_NAME_LEN]; + __u32 info_len, curr_prog_id; + int prog_fd; + int err = 1; + + if (bpf_xdp_query_id(ifindex, xdp_flags, &curr_prog_id)) { + printf("ERROR: bpf_xdp_query_id failed (%s)\n", + strerror(errno)); + return err; + } + + if (!curr_prog_id) { + printf("ERROR: flags(0x%x) xdp prog is not attached to %s\n", + xdp_flags, ifname); + return err; + } + + info_len = sizeof(prog_info); + prog_fd = bpf_prog_get_fd_by_id(curr_prog_id); + if (prog_fd < 0) { + printf("ERROR: bpf_prog_get_fd_by_id failed (%s)\n", + strerror(errno)); + return prog_fd; + } + + err = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &info_len); + if (err) { + printf("ERROR: bpf_obj_get_info_by_fd failed (%s)\n", + strerror(errno)); + goto close_out; + } + snprintf(prog_name, sizeof(prog_name), "%s_prog", app_name); + prog_name[BPF_OBJ_NAME_LEN - 1] = '\0'; + + if (strcmp(prog_info.name, prog_name)) { + printf("ERROR: %s isn't attached to %s\n", app_name, ifname); + err = 1; + goto close_out; + } + + opts.old_prog_fd = prog_fd; + err = bpf_xdp_detach(ifindex, xdp_flags, &opts); + if (err < 0) + printf("ERROR: failed to detach program from %s (%s)\n", + ifname, strerror(errno)); + /* TODO: Remember to cleanup map, when adding use of shared map + * bpf_map_delete_elem((map_fd, &idx); + */ +close_out: + close(prog_fd); + return err; +} + +static void usage(const char *prog) +{ + fprintf(stderr, + "usage: %s [OPTS] interface-list\n" + "\nOPTS:\n" + " -d detach program\n" + " -S use skb-mode\n" + " -F force loading prog\n" + " -D direct table lookups (skip fib rules)\n", + prog); +} + +int main(int argc, char **argv) +{ + const char *prog_name = "xdp_fwd"; + struct bpf_program *prog = NULL; + struct bpf_program *pos; + const char *sec_name; + int prog_fd = -1, 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]); + + if (access(filename, O_RDONLY) < 0) { + printf("error accessing file %s: %s\n", + filename, strerror(errno)); + return 1; + } + + obj = bpf_object__open_file(filename, NULL); + if (libbpf_get_error(obj)) + return 1; + + prog = bpf_object__next_program(obj, NULL); + bpf_program__set_type(prog, BPF_PROG_TYPE_XDP); + + err = bpf_object__load(obj); + 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; + } + + bpf_object__for_each_program(pos, obj) { + sec_name = bpf_program__section_name(pos); + if (sec_name && !strcmp(sec_name, prog_name)) { + prog = pos; + break; + } + } + 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], prog_name); + if (err) + ret = err; + } else { + err = do_attach(idx, prog_fd, map_fd, argv[i]); + if (err) + ret = err; + } + } + + return ret; +} |