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c6ffd1ff NS |
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> | |
9e859e8f | 16 | #include <net/if.h> |
c6ffd1ff NS |
17 | #include <sys/resource.h> |
18 | #include <arpa/inet.h> | |
19 | #include <netinet/ether.h> | |
20 | #include <unistd.h> | |
21 | #include <time.h> | |
4d18f6de DL |
22 | #include "bpf.h" |
23 | #include "libbpf.h" | |
c6ffd1ff NS |
24 | |
25 | #define STATS_INTERVAL_S 2U | |
26 | ||
27 | static int ifindex = -1; | |
743e568c | 28 | static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST; |
3b7a8ec2 | 29 | static __u32 prog_id; |
c6ffd1ff NS |
30 | |
31 | static void int_exit(int sig) | |
32 | { | |
3b7a8ec2 MF |
33 | __u32 curr_prog_id = 0; |
34 | ||
35 | if (ifindex > -1) { | |
36 | if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) { | |
37 | printf("bpf_get_link_xdp_id failed\n"); | |
38 | exit(1); | |
39 | } | |
40 | if (prog_id == curr_prog_id) | |
41 | bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); | |
42 | else if (!curr_prog_id) | |
43 | printf("couldn't find a prog id on a given iface\n"); | |
44 | else | |
45 | printf("program on interface changed, not removing\n"); | |
46 | } | |
c6ffd1ff NS |
47 | exit(0); |
48 | } | |
49 | ||
50 | /* simple "icmp packet too big sent" counter | |
51 | */ | |
be5bca44 | 52 | static void poll_stats(unsigned int map_fd, unsigned int kill_after_s) |
c6ffd1ff NS |
53 | { |
54 | time_t started_at = time(NULL); | |
55 | __u64 value = 0; | |
56 | int key = 0; | |
57 | ||
58 | ||
59 | while (!kill_after_s || time(NULL) - started_at <= kill_after_s) { | |
60 | sleep(STATS_INTERVAL_S); | |
61 | ||
be5bca44 | 62 | assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0); |
c6ffd1ff NS |
63 | |
64 | printf("icmp \"packet too big\" sent: %10llu pkts\n", value); | |
65 | } | |
66 | } | |
67 | ||
68 | static void usage(const char *cmd) | |
69 | { | |
70 | printf("Start a XDP prog which send ICMP \"packet too big\" \n" | |
71 | "messages if ingress packet is bigger then MAX_SIZE bytes\n"); | |
72 | printf("Usage: %s [...]\n", cmd); | |
9e859e8f | 73 | printf(" -i <ifname|ifindex> Interface\n"); |
c6ffd1ff NS |
74 | printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n"); |
75 | printf(" -S use skb-mode\n"); | |
76 | printf(" -N enforce native mode\n"); | |
743e568c | 77 | printf(" -F force loading prog\n"); |
c6ffd1ff NS |
78 | printf(" -h Display this help\n"); |
79 | } | |
80 | ||
81 | int main(int argc, char **argv) | |
82 | { | |
be5bca44 JK |
83 | struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; |
84 | struct bpf_prog_load_attr prog_load_attr = { | |
85 | .prog_type = BPF_PROG_TYPE_XDP, | |
86 | }; | |
c6ffd1ff | 87 | unsigned char opt_flags[256] = {}; |
743e568c | 88 | const char *optstr = "i:T:SNFh"; |
3b7a8ec2 MF |
89 | struct bpf_prog_info info = {}; |
90 | __u32 info_len = sizeof(info); | |
c6ffd1ff | 91 | unsigned int kill_after_s = 0; |
be5bca44 JK |
92 | int i, prog_fd, map_fd, opt; |
93 | struct bpf_object *obj; | |
94 | struct bpf_map *map; | |
c6ffd1ff | 95 | char filename[256]; |
3b7a8ec2 | 96 | int err; |
c6ffd1ff NS |
97 | |
98 | for (i = 0; i < strlen(optstr); i++) | |
99 | if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z') | |
100 | opt_flags[(unsigned char)optstr[i]] = 1; | |
101 | ||
102 | while ((opt = getopt(argc, argv, optstr)) != -1) { | |
103 | ||
104 | switch (opt) { | |
105 | case 'i': | |
9e859e8f DL |
106 | ifindex = if_nametoindex(optarg); |
107 | if (!ifindex) | |
108 | ifindex = atoi(optarg); | |
c6ffd1ff NS |
109 | break; |
110 | case 'T': | |
111 | kill_after_s = atoi(optarg); | |
112 | break; | |
113 | case 'S': | |
114 | xdp_flags |= XDP_FLAGS_SKB_MODE; | |
115 | break; | |
116 | case 'N': | |
117 | xdp_flags |= XDP_FLAGS_DRV_MODE; | |
118 | break; | |
743e568c MF |
119 | case 'F': |
120 | xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST; | |
121 | break; | |
c6ffd1ff NS |
122 | default: |
123 | usage(argv[0]); | |
124 | return 1; | |
125 | } | |
126 | opt_flags[opt] = 0; | |
127 | } | |
128 | ||
129 | for (i = 0; i < strlen(optstr); i++) { | |
130 | if (opt_flags[(unsigned int)optstr[i]]) { | |
131 | fprintf(stderr, "Missing argument -%c\n", optstr[i]); | |
132 | usage(argv[0]); | |
133 | return 1; | |
134 | } | |
135 | } | |
136 | ||
137 | if (setrlimit(RLIMIT_MEMLOCK, &r)) { | |
138 | perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)"); | |
139 | return 1; | |
140 | } | |
141 | ||
9e859e8f DL |
142 | if (!ifindex) { |
143 | fprintf(stderr, "Invalid ifname\n"); | |
144 | return 1; | |
145 | } | |
146 | ||
c6ffd1ff | 147 | snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); |
be5bca44 JK |
148 | prog_load_attr.file = filename; |
149 | ||
150 | if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd)) | |
151 | return 1; | |
c6ffd1ff | 152 | |
be5bca44 JK |
153 | map = bpf_map__next(NULL, obj); |
154 | if (!map) { | |
155 | printf("finding a map in obj file failed\n"); | |
c6ffd1ff NS |
156 | return 1; |
157 | } | |
be5bca44 | 158 | map_fd = bpf_map__fd(map); |
c6ffd1ff | 159 | |
be5bca44 | 160 | if (!prog_fd) { |
c6ffd1ff NS |
161 | printf("load_bpf_file: %s\n", strerror(errno)); |
162 | return 1; | |
163 | } | |
164 | ||
165 | signal(SIGINT, int_exit); | |
166 | signal(SIGTERM, int_exit); | |
167 | ||
be5bca44 | 168 | if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) { |
c6ffd1ff NS |
169 | printf("link set xdp fd failed\n"); |
170 | return 1; | |
171 | } | |
172 | ||
3b7a8ec2 MF |
173 | err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len); |
174 | if (err) { | |
175 | printf("can't get prog info - %s\n", strerror(errno)); | |
176 | return 1; | |
177 | } | |
178 | prog_id = info.id; | |
c6ffd1ff | 179 | |
3b7a8ec2 MF |
180 | poll_stats(map_fd, kill_after_s); |
181 | int_exit(0); | |
c6ffd1ff NS |
182 | |
183 | return 0; | |
184 | } |