linux/samples/bpf/xdp1_user.c
Jakub Kicinski be5bca44aa samples: bpf: convert some XDP samples from bpf_load to libbpf
Now that we can use full powers of libbpf in BPF samples, we
should perhaps make the simplest XDP programs not depend on
bpf_load helpers.  This way newcomers will be exposed to the
recommended library from the start.

Use of bpf_prog_load_xattr() will also make it trivial to later
on request offload of the programs by simply adding ifindex to
the xattr.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-11 01:44:17 +02:00

139 lines
2.8 KiB
C

/* Copyright (c) 2016 PLUMgrid
*
* 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.
*/
#include <linux/bpf.h>
#include <linux/if_link.h>
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libgen.h>
#include <sys/resource.h>
#include "bpf_util.h"
#include "bpf/bpf.h"
#include "bpf/libbpf.h"
static int ifindex;
static __u32 xdp_flags;
static void int_exit(int sig)
{
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
exit(0);
}
/* simple per-protocol drop counter
*/
static void poll_stats(int map_fd, int interval)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
const unsigned int nr_keys = 256;
__u64 values[nr_cpus], prev[nr_keys][nr_cpus];
__u32 key;
int i;
memset(prev, 0, sizeof(prev));
while (1) {
sleep(interval);
for (key = 0; key < nr_keys; key++) {
__u64 sum = 0;
assert(bpf_map_lookup_elem(map_fd, &key, values) == 0);
for (i = 0; i < nr_cpus; i++)
sum += (values[i] - prev[key][i]);
if (sum)
printf("proto %u: %10llu pkt/s\n",
key, sum / interval);
memcpy(prev[key], values, sizeof(values));
}
}
}
static void usage(const char *prog)
{
fprintf(stderr,
"usage: %s [OPTS] IFINDEX\n\n"
"OPTS:\n"
" -S use skb-mode\n"
" -N enforce native mode\n",
prog);
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
struct bpf_prog_load_attr prog_load_attr = {
.prog_type = BPF_PROG_TYPE_XDP,
};
const char *optstr = "SN";
int prog_fd, map_fd, opt;
struct bpf_object *obj;
struct bpf_map *map;
char filename[256];
while ((opt = getopt(argc, argv, optstr)) != -1) {
switch (opt) {
case 'S':
xdp_flags |= XDP_FLAGS_SKB_MODE;
break;
case 'N':
xdp_flags |= XDP_FLAGS_DRV_MODE;
break;
default:
usage(basename(argv[0]));
return 1;
}
}
if (optind == argc) {
usage(basename(argv[0]));
return 1;
}
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
return 1;
}
ifindex = strtoul(argv[optind], NULL, 0);
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
prog_load_attr.file = filename;
if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
return 1;
map = bpf_map__next(NULL, obj);
if (!map) {
printf("finding a map in obj file failed\n");
return 1;
}
map_fd = bpf_map__fd(map);
if (!prog_fd) {
printf("load_bpf_file: %s\n", strerror(errno));
return 1;
}
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
printf("link set xdp fd failed\n");
return 1;
}
poll_stats(map_fd, 2);
return 0;
}