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