Orange Pi5 kernel

/* SPDX-License-Identifier: GPL-2.0
 * Copyright (c) 2018 Facebook
 *
 * 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 <net/if.h>
#include <sys/resource.h>
#include <arpa/inet.h>
#include <netinet/ether.h>
#include <unistd.h>
#include <time.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
 
#define STATS_INTERVAL_S 2U
#define MAX_PCKT_SIZE 600
 
static int ifindex = -1;
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 (ifindex > -1) {
<------><------>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 iface\n");
<------><------>else
<------><------><------>printf("program on interface changed, not removing\n");
<------>}
<------>exit(0);
}
 
/* simple "icmp packet too big sent" counter
 */
static void poll_stats(unsigned int map_fd, unsigned int kill_after_s)
{
<------>time_t started_at = time(NULL);
<------>__u64 value = 0;
<------>int key = 0;
 
 
<------>while (!kill_after_s || time(NULL) - started_at <= kill_after_s) {
<------><------>sleep(STATS_INTERVAL_S);
 
<------><------>assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
 
<------><------>printf("icmp \"packet too big\" sent: %10llu pkts\n", value);
<------>}
}
 
static void usage(const char *cmd)
{
<------>printf("Start a XDP prog which send ICMP \"packet too big\" \n"
<------><------>"messages if ingress packet is bigger then MAX_SIZE bytes\n");
<------>printf("Usage: %s [...]\n", cmd);
<------>printf("    -i <ifname|ifindex> Interface\n");
<------>printf("    -T <stop-after-X-seconds> Default: 0 (forever)\n");
<------>printf("    -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE);
<------>printf("    -S use skb-mode\n");
<------>printf("    -N enforce native mode\n");
<------>printf("    -F force loading prog\n");
<------>printf("    -h Display this help\n");
}
 
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,
<------>};
<------>unsigned char opt_flags[256] = {};
<------>const char *optstr = "i:T:P:SNFh";
<------>struct bpf_prog_info info = {};
<------>__u32 info_len = sizeof(info);
<------>unsigned int kill_after_s = 0;
<------>int i, prog_fd, map_fd, opt;
<------>struct bpf_object *obj;
<------>__u32 max_pckt_size = 0;
<------>__u32 key = 0;
<------>char filename[256];
<------>int err;
 
<------>for (i = 0; i < strlen(optstr); i++)
<------><------>if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z')
<------><------><------>opt_flags[(unsigned char)optstr[i]] = 1;
 
<------>while ((opt = getopt(argc, argv, optstr)) != -1) {
 
<------><------>switch (opt) {
<------><------>case 'i':
<------><------><------>ifindex = if_nametoindex(optarg);
<------><------><------>if (!ifindex)
<------><------><------><------>ifindex = atoi(optarg);
<------><------><------>break;
<------><------>case 'T':
<------><------><------>kill_after_s = atoi(optarg);
<------><------><------>break;
<------><------>case 'P':
<------><------><------>max_pckt_size = atoi(optarg);
<------><------><------>break;
<------><------>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(argv[0]);
<------><------><------>return 1;
<------><------>}
<------><------>opt_flags[opt] = 0;
<------>}
 
<------>if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
<------><------>xdp_flags |= XDP_FLAGS_DRV_MODE;
 
<------>for (i = 0; i < strlen(optstr); i++) {
<------><------>if (opt_flags[(unsigned int)optstr[i]]) {
<------><------><------>fprintf(stderr, "Missing argument -%c\n", optstr[i]);
<------><------><------>usage(argv[0]);
<------><------><------>return 1;
<------><------>}
<------>}
 
<------>if (setrlimit(RLIMIT_MEMLOCK, &r)) {
<------><------>perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)");
<------><------>return 1;
<------>}
 
<------>if (!ifindex) {
<------><------>fprintf(stderr, "Invalid ifname\n");
<------><------>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;
 
<------>/* static global var 'max_pcktsz' is accessible from .data section */
<------>if (max_pckt_size) {
<------><------>map_fd = bpf_object__find_map_fd_by_name(obj, "xdp_adju.data");
<------><------>if (map_fd < 0) {
<------><------><------>printf("finding a max_pcktsz map in obj file failed\n");
<------><------><------>return 1;
<------><------>}
<------><------>bpf_map_update_elem(map_fd, &key, &max_pckt_size, BPF_ANY);
<------>}
 
<------>/* fetch icmpcnt map */
<------>map_fd = bpf_object__find_map_fd_by_name(obj, "icmpcnt");
<------>if (map_fd < 0) {
<------><------>printf("finding a icmpcnt map in obj file failed\n");
<------><------>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 1;
<------>}
<------>prog_id = info.id;
 
<------>poll_stats(map_fd, kill_after_s);
<------>int_exit(0);
 
<------>return 0;
}