linux/samples/bpf/xdp_fwd_user.c
David Ahern fe616055f7 samples/bpf: Add example of ipv4 and ipv6 forwarding in XDP
Simple example of fast-path forwarding. It has a serious flaw
in not verifying the egress device index supports XDP forwarding.
If the egress device does not packets are dropped.

Take this only as a simple example of fast-path forwarding.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-11 00:10:57 +02:00

137 lines
2.7 KiB
C

// 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_load.h"
#include "bpf_util.h"
#include "libbpf.h"
static int do_attach(int idx, int fd, const char *name)
{
int err;
err = bpf_set_link_xdp_fd(idx, fd, 0);
if (err < 0)
printf("ERROR: failed to attach program to %s\n", name);
return err;
}
static int do_detach(int idx, const char *name)
{
int err;
err = bpf_set_link_xdp_fd(idx, -1, 0);
if (err < 0)
printf("ERROR: failed to detach program from %s\n", name);
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)
{
char filename[PATH_MAX];
int opt, i, idx, err;
int prog_id = 0;
int attach = 1;
int ret = 0;
while ((opt = getopt(argc, argv, ":dD")) != -1) {
switch (opt) {
case 'd':
attach = 0;
break;
case 'D':
prog_id = 1;
break;
default:
usage(basename(argv[0]));
return 1;
}
}
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;
}
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 1;
}
if (!prog_fd[prog_id]) {
printf("load_bpf_file: %s\n", strerror(errno));
return 1;
}
}
if (attach) {
for (i = 1; i < 64; ++i)
bpf_map_update_elem(map_fd[0], &i, &i, 0);
}
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[prog_id], argv[i]);
if (err)
ret = err;
}
}
return ret;
}