1 /* SPDX-License-Identifier: GPL-2.0 2 * Copyright (c) 2018 Facebook 3 * 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. 7 */ 8 #include <linux/bpf.h> 9 #include <linux/if_link.h> 10 #include <assert.h> 11 #include <errno.h> 12 #include <signal.h> 13 #include <stdio.h> 14 #include <stdlib.h> 15 #include <string.h> 16 #include <sys/resource.h> 17 #include <arpa/inet.h> 18 #include <netinet/ether.h> 19 #include <unistd.h> 20 #include <time.h> 21 #include "bpf_load.h" 22 #include "libbpf.h" 23 #include "bpf_util.h" 24 25 #define STATS_INTERVAL_S 2U 26 27 static int ifindex = -1; 28 static __u32 xdp_flags; 29 30 static void int_exit(int sig) 31 { 32 if (ifindex > -1) 33 bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); 34 exit(0); 35 } 36 37 /* simple "icmp packet too big sent" counter 38 */ 39 static void poll_stats(unsigned int kill_after_s) 40 { 41 time_t started_at = time(NULL); 42 __u64 value = 0; 43 int key = 0; 44 45 46 while (!kill_after_s || time(NULL) - started_at <= kill_after_s) { 47 sleep(STATS_INTERVAL_S); 48 49 assert(bpf_map_lookup_elem(map_fd[0], &key, &value) == 0); 50 51 printf("icmp \"packet too big\" sent: %10llu pkts\n", value); 52 } 53 } 54 55 static void usage(const char *cmd) 56 { 57 printf("Start a XDP prog which send ICMP \"packet too big\" \n" 58 "messages if ingress packet is bigger then MAX_SIZE bytes\n"); 59 printf("Usage: %s [...]\n", cmd); 60 printf(" -i <ifindex> Interface Index\n"); 61 printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n"); 62 printf(" -S use skb-mode\n"); 63 printf(" -N enforce native mode\n"); 64 printf(" -h Display this help\n"); 65 } 66 67 int main(int argc, char **argv) 68 { 69 unsigned char opt_flags[256] = {}; 70 unsigned int kill_after_s = 0; 71 const char *optstr = "i:T:SNh"; 72 struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; 73 char filename[256]; 74 int opt; 75 int i; 76 77 78 for (i = 0; i < strlen(optstr); i++) 79 if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z') 80 opt_flags[(unsigned char)optstr[i]] = 1; 81 82 while ((opt = getopt(argc, argv, optstr)) != -1) { 83 84 switch (opt) { 85 case 'i': 86 ifindex = atoi(optarg); 87 break; 88 case 'T': 89 kill_after_s = atoi(optarg); 90 break; 91 case 'S': 92 xdp_flags |= XDP_FLAGS_SKB_MODE; 93 break; 94 case 'N': 95 xdp_flags |= XDP_FLAGS_DRV_MODE; 96 break; 97 default: 98 usage(argv[0]); 99 return 1; 100 } 101 opt_flags[opt] = 0; 102 } 103 104 for (i = 0; i < strlen(optstr); i++) { 105 if (opt_flags[(unsigned int)optstr[i]]) { 106 fprintf(stderr, "Missing argument -%c\n", optstr[i]); 107 usage(argv[0]); 108 return 1; 109 } 110 } 111 112 if (setrlimit(RLIMIT_MEMLOCK, &r)) { 113 perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)"); 114 return 1; 115 } 116 117 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 118 119 if (load_bpf_file(filename)) { 120 printf("%s", bpf_log_buf); 121 return 1; 122 } 123 124 if (!prog_fd[0]) { 125 printf("load_bpf_file: %s\n", strerror(errno)); 126 return 1; 127 } 128 129 signal(SIGINT, int_exit); 130 signal(SIGTERM, int_exit); 131 132 if (bpf_set_link_xdp_fd(ifindex, prog_fd[0], xdp_flags) < 0) { 133 printf("link set xdp fd failed\n"); 134 return 1; 135 } 136 137 poll_stats(kill_after_s); 138 139 bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); 140 141 return 0; 142 } 143