xdp1_user.c
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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2016 PLUMgrid
*/
#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 <net/if.h>
#include "bpf_util.h"
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
static int ifindex;
static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
static __u32 prog_id;
static void int_exit(int sig)
{
__u32 curr_prog_id = 0;
if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
printf("bpf_get_link_xdp_id failed\n");
exit(1);
}
if (prog_id == curr_prog_id)
bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
else if (!curr_prog_id)
printf("couldn't find a prog id on a given interface\n");
else
printf("program on interface changed, not removing\n");
exit(0);
}
/* simple per-protocol drop counter
*/
static void poll_stats(int map_fd, int interval)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
__u64 values[nr_cpus], prev[UINT8_MAX] = { 0 };
int i;
while (1) {
__u32 key = UINT32_MAX;
sleep(interval);
while (bpf_map_get_next_key(map_fd, &key, &key) != -1) {
__u64 sum = 0;
assert(bpf_map_lookup_elem(map_fd, &key, values) == 0);
for (i = 0; i < nr_cpus; i++)
sum += values[i];
if (sum > prev[key])
printf("proto %u: %10llu pkt/s\n",
key, (sum - prev[key]) / interval);
prev[key] = sum;
}
}
}
static void usage(const char *prog)
{
fprintf(stderr,
"usage: %s [OPTS] IFACE\n\n"
"OPTS:\n"
" -S use skb-mode\n"
" -N enforce native mode\n"
" -F force loading prog\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,
};
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
const char *optstr = "FSN";
int prog_fd, map_fd, opt;
struct bpf_object *obj;
struct bpf_map *map;
char filename[256];
int err;
while ((opt = getopt(argc, argv, optstr)) != -1) {
switch (opt) {
case 'S':
xdp_flags |= XDP_FLAGS_SKB_MODE;
break;
case 'N':
/* default, set below */
break;
case 'F':
xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
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 (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
return 1;
}
ifindex = if_nametoindex(argv[optind]);
if (!ifindex) {
perror("if_nametoindex");
return 1;
}
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("bpf_prog_load_xattr: %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;
}
err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
if (err) {
printf("can't get prog info - %s\n", strerror(errno));
return err;
}
prog_id = info.id;
poll_stats(map_fd, 2);
return 0;
}