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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> | |
7cf245a3 THJ |
22 | #include <bpf/bpf.h> |
23 | #include <bpf/libbpf.h> | |
c6ffd1ff NS |
24 | |
25 | #define STATS_INTERVAL_S 2U | |
8fdf5b78 | 26 | #define MAX_PCKT_SIZE 600 |
c6ffd1ff NS |
27 | |
28 | static int ifindex = -1; | |
743e568c | 29 | static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST; |
3b7a8ec2 | 30 | static __u32 prog_id; |
c6ffd1ff NS |
31 | |
32 | static void int_exit(int sig) | |
33 | { | |
3b7a8ec2 MF |
34 | __u32 curr_prog_id = 0; |
35 | ||
36 | if (ifindex > -1) { | |
37 | if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) { | |
38 | printf("bpf_get_link_xdp_id failed\n"); | |
39 | exit(1); | |
40 | } | |
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"); | |
45 | else | |
46 | printf("program on interface changed, not removing\n"); | |
47 | } | |
c6ffd1ff NS |
48 | exit(0); |
49 | } | |
50 | ||
51 | /* simple "icmp packet too big sent" counter | |
52 | */ | |
be5bca44 | 53 | static void poll_stats(unsigned int map_fd, unsigned int kill_after_s) |
c6ffd1ff NS |
54 | { |
55 | time_t started_at = time(NULL); | |
56 | __u64 value = 0; | |
57 | int key = 0; | |
58 | ||
59 | ||
60 | while (!kill_after_s || time(NULL) - started_at <= kill_after_s) { | |
61 | sleep(STATS_INTERVAL_S); | |
62 | ||
be5bca44 | 63 | assert(bpf_map_lookup_elem(map_fd, &key, &value) == 0); |
c6ffd1ff NS |
64 | |
65 | printf("icmp \"packet too big\" sent: %10llu pkts\n", value); | |
66 | } | |
67 | } | |
68 | ||
69 | static void usage(const char *cmd) | |
70 | { | |
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); | |
9e859e8f | 74 | printf(" -i <ifname|ifindex> Interface\n"); |
c6ffd1ff | 75 | printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n"); |
8fdf5b78 | 76 | printf(" -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE); |
c6ffd1ff NS |
77 | printf(" -S use skb-mode\n"); |
78 | printf(" -N enforce native mode\n"); | |
743e568c | 79 | printf(" -F force loading prog\n"); |
c6ffd1ff NS |
80 | printf(" -h Display this help\n"); |
81 | } | |
82 | ||
83 | int main(int argc, char **argv) | |
84 | { | |
be5bca44 JK |
85 | struct bpf_prog_load_attr prog_load_attr = { |
86 | .prog_type = BPF_PROG_TYPE_XDP, | |
87 | }; | |
c6ffd1ff | 88 | unsigned char opt_flags[256] = {}; |
8fdf5b78 | 89 | const char *optstr = "i:T:P:SNFh"; |
3b7a8ec2 MF |
90 | struct bpf_prog_info info = {}; |
91 | __u32 info_len = sizeof(info); | |
c6ffd1ff | 92 | unsigned int kill_after_s = 0; |
be5bca44 JK |
93 | int i, prog_fd, map_fd, opt; |
94 | struct bpf_object *obj; | |
8fdf5b78 DL |
95 | __u32 max_pckt_size = 0; |
96 | __u32 key = 0; | |
c6ffd1ff | 97 | char filename[256]; |
3b7a8ec2 | 98 | int err; |
c6ffd1ff NS |
99 | |
100 | for (i = 0; i < strlen(optstr); i++) | |
101 | if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z') | |
102 | opt_flags[(unsigned char)optstr[i]] = 1; | |
103 | ||
104 | while ((opt = getopt(argc, argv, optstr)) != -1) { | |
105 | ||
106 | switch (opt) { | |
107 | case 'i': | |
9e859e8f DL |
108 | ifindex = if_nametoindex(optarg); |
109 | if (!ifindex) | |
110 | ifindex = atoi(optarg); | |
c6ffd1ff NS |
111 | break; |
112 | case 'T': | |
113 | kill_after_s = atoi(optarg); | |
114 | break; | |
8fdf5b78 DL |
115 | case 'P': |
116 | max_pckt_size = atoi(optarg); | |
117 | break; | |
c6ffd1ff NS |
118 | case 'S': |
119 | xdp_flags |= XDP_FLAGS_SKB_MODE; | |
120 | break; | |
121 | case 'N': | |
d50ecc46 | 122 | /* default, set below */ |
c6ffd1ff | 123 | break; |
743e568c MF |
124 | case 'F': |
125 | xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST; | |
126 | break; | |
c6ffd1ff NS |
127 | default: |
128 | usage(argv[0]); | |
129 | return 1; | |
130 | } | |
131 | opt_flags[opt] = 0; | |
132 | } | |
133 | ||
d50ecc46 THJ |
134 | if (!(xdp_flags & XDP_FLAGS_SKB_MODE)) |
135 | xdp_flags |= XDP_FLAGS_DRV_MODE; | |
136 | ||
c6ffd1ff NS |
137 | for (i = 0; i < strlen(optstr); i++) { |
138 | if (opt_flags[(unsigned int)optstr[i]]) { | |
139 | fprintf(stderr, "Missing argument -%c\n", optstr[i]); | |
140 | usage(argv[0]); | |
141 | return 1; | |
142 | } | |
143 | } | |
144 | ||
9e859e8f DL |
145 | if (!ifindex) { |
146 | fprintf(stderr, "Invalid ifname\n"); | |
147 | return 1; | |
148 | } | |
149 | ||
c6ffd1ff | 150 | snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); |
be5bca44 JK |
151 | prog_load_attr.file = filename; |
152 | ||
153 | if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd)) | |
154 | return 1; | |
c6ffd1ff | 155 | |
8fdf5b78 DL |
156 | /* static global var 'max_pcktsz' is accessible from .data section */ |
157 | if (max_pckt_size) { | |
158 | map_fd = bpf_object__find_map_fd_by_name(obj, "xdp_adju.data"); | |
159 | if (map_fd < 0) { | |
160 | printf("finding a max_pcktsz map in obj file failed\n"); | |
161 | return 1; | |
162 | } | |
163 | bpf_map_update_elem(map_fd, &key, &max_pckt_size, BPF_ANY); | |
c6ffd1ff NS |
164 | } |
165 | ||
8fdf5b78 DL |
166 | /* fetch icmpcnt map */ |
167 | map_fd = bpf_object__find_map_fd_by_name(obj, "icmpcnt"); | |
168 | if (map_fd < 0) { | |
169 | printf("finding a icmpcnt map in obj file failed\n"); | |
c6ffd1ff NS |
170 | return 1; |
171 | } | |
172 | ||
173 | signal(SIGINT, int_exit); | |
174 | signal(SIGTERM, int_exit); | |
175 | ||
be5bca44 | 176 | if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) { |
c6ffd1ff NS |
177 | printf("link set xdp fd failed\n"); |
178 | return 1; | |
179 | } | |
180 | ||
3b7a8ec2 MF |
181 | err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len); |
182 | if (err) { | |
183 | printf("can't get prog info - %s\n", strerror(errno)); | |
184 | return 1; | |
185 | } | |
186 | prog_id = info.id; | |
c6ffd1ff | 187 | |
3b7a8ec2 MF |
188 | poll_stats(map_fd, kill_after_s); |
189 | int_exit(0); | |
c6ffd1ff NS |
190 | |
191 | return 0; | |
192 | } |