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author | Nikita V. Shirokov <tehnerd@tehnerd.com> | 2018-04-17 21:42:23 -0700 |
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committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-04-18 23:34:17 +0200 |
commit | c6ffd1ff785675c4a572c79f0e55ba5735edbaa0 (patch) | |
tree | 89bf245d8d4d86f46b4bea11473d9441b1f53782 /samples/bpf/xdp_adjust_tail_user.c | |
parent | 0367d0a29427d5916b98cf31dfc85a8293540614 (diff) | |
download | linux-stable-c6ffd1ff785675c4a572c79f0e55ba5735edbaa0.tar.gz linux-stable-c6ffd1ff785675c4a572c79f0e55ba5735edbaa0.tar.bz2 linux-stable-c6ffd1ff785675c4a572c79f0e55ba5735edbaa0.zip |
bpf: add bpf_xdp_adjust_tail sample prog
adding bpf's sample program which is using bpf_xdp_adjust_tail helper
by generating ICMPv4 "packet to big" message if ingress packet's size is
bigger then 600 bytes
Signed-off-by: Nikita V. Shirokov <tehnerd@tehnerd.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'samples/bpf/xdp_adjust_tail_user.c')
-rw-r--r-- | samples/bpf/xdp_adjust_tail_user.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c new file mode 100644 index 000000000000..f621a541b574 --- /dev/null +++ b/samples/bpf/xdp_adjust_tail_user.c @@ -0,0 +1,142 @@ +/* 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 <sys/resource.h> +#include <arpa/inet.h> +#include <netinet/ether.h> +#include <unistd.h> +#include <time.h> +#include "bpf_load.h" +#include "libbpf.h" +#include "bpf_util.h" + +#define STATS_INTERVAL_S 2U + +static int ifindex = -1; +static __u32 xdp_flags; + +static void int_exit(int sig) +{ + if (ifindex > -1) + bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); + exit(0); +} + +/* simple "icmp packet too big sent" counter + */ +static void poll_stats(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[0], &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 <ifindex> Interface Index\n"); + printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n"); + printf(" -S use skb-mode\n"); + printf(" -N enforce native mode\n"); + printf(" -h Display this help\n"); +} + +int main(int argc, char **argv) +{ + unsigned char opt_flags[256] = {}; + unsigned int kill_after_s = 0; + const char *optstr = "i:T:SNh"; + struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; + char filename[256]; + int opt; + int i; + + + 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 = atoi(optarg); + break; + case 'T': + kill_after_s = atoi(optarg); + break; + case 'S': + xdp_flags |= XDP_FLAGS_SKB_MODE; + break; + case 'N': + xdp_flags |= XDP_FLAGS_DRV_MODE; + break; + default: + usage(argv[0]); + return 1; + } + opt_flags[opt] = 0; + } + + 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; + } + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + if (!prog_fd[0]) { + printf("load_bpf_file: %s\n", strerror(errno)); + return 1; + } + + signal(SIGINT, int_exit); + signal(SIGTERM, int_exit); + + if (bpf_set_link_xdp_fd(ifindex, prog_fd[0], xdp_flags) < 0) { + printf("link set xdp fd failed\n"); + return 1; + } + + poll_stats(kill_after_s); + + bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); + + return 0; +} |