1 /* SPDX-License-Identifier: GPL-2.0
2 * Copyright (c) 2018 Facebook
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
9 #include <linux/if_link.h>
17 #include <sys/resource.h>
18 #include <arpa/inet.h>
19 #include <netinet/ether.h>
25 #define STATS_INTERVAL_S 2U
26 #define MAX_PCKT_SIZE 600
28 static int ifindex = -1;
29 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
32 static void int_exit(int sig)
34 __u32 curr_prog_id = 0;
37 if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
38 printf("bpf_get_link_xdp_id failed\n");
41 if (prog_id == curr_prog_id)
42 bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
43 else if (!curr_prog_id)
44 printf("couldn't find a prog id on a given iface\n");
46 printf("program on interface changed, not removing\n");
51 /* simple "icmp packet too big sent" counter
53 static void poll_stats(unsigned int map_fd, unsigned int kill_after_s)
55 time_t started_at = time(NULL);
60 while (!kill_after_s || time(NULL) - started_at <= kill_after_s) {
61 sleep(STATS_INTERVAL_S);
63 assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0);
65 printf("icmp \"packet too big\" sent: %10llu pkts\n", value);
69 static void usage(const char *cmd)
71 printf("Start a XDP prog which send ICMP \"packet too big\" \n"
72 "messages if ingress packet is bigger then MAX_SIZE bytes\n");
73 printf("Usage: %s [...]\n", cmd);
74 printf(" -i <ifname|ifindex> Interface\n");
75 printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n");
76 printf(" -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE);
77 printf(" -S use skb-mode\n");
78 printf(" -N enforce native mode\n");
79 printf(" -F force loading prog\n");
80 printf(" -h Display this help\n");
83 int main(int argc, char **argv)
85 struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
86 struct bpf_prog_load_attr prog_load_attr = {
87 .prog_type = BPF_PROG_TYPE_XDP,
89 unsigned char opt_flags[256] = {};
90 const char *optstr = "i:T:P:SNFh";
91 struct bpf_prog_info info = {};
92 __u32 info_len = sizeof(info);
93 unsigned int kill_after_s = 0;
94 int i, prog_fd, map_fd, opt;
95 struct bpf_object *obj;
96 __u32 max_pckt_size = 0;
101 for (i = 0; i < strlen(optstr); i++)
102 if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z')
103 opt_flags[(unsigned char)optstr[i]] = 1;
105 while ((opt = getopt(argc, argv, optstr)) != -1) {
109 ifindex = if_nametoindex(optarg);
111 ifindex = atoi(optarg);
114 kill_after_s = atoi(optarg);
117 max_pckt_size = atoi(optarg);
120 xdp_flags |= XDP_FLAGS_SKB_MODE;
123 xdp_flags |= XDP_FLAGS_DRV_MODE;
126 xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
135 for (i = 0; i < strlen(optstr); i++) {
136 if (opt_flags[(unsigned int)optstr[i]]) {
137 fprintf(stderr, "Missing argument -%c\n", optstr[i]);
143 if (setrlimit(RLIMIT_MEMLOCK, &r)) {
144 perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)");
149 fprintf(stderr, "Invalid ifname\n");
153 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
154 prog_load_attr.file = filename;
156 if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
159 /* static global var 'max_pcktsz' is accessible from .data section */
161 map_fd = bpf_object__find_map_fd_by_name(obj, "xdp_adju.data");
163 printf("finding a max_pcktsz map in obj file failed\n");
166 bpf_map_update_elem(map_fd, &key, &max_pckt_size, BPF_ANY);
169 /* fetch icmpcnt map */
170 map_fd = bpf_object__find_map_fd_by_name(obj, "icmpcnt");
172 printf("finding a icmpcnt map in obj file failed\n");
176 signal(SIGINT, int_exit);
177 signal(SIGTERM, int_exit);
179 if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) {
180 printf("link set xdp fd failed\n");
184 err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
186 printf("can't get prog info - %s\n", strerror(errno));
191 poll_stats(map_fd, kill_after_s);