diff options
Diffstat (limited to 'samples/bpf/xdp_adjust_tail_user.c')
| -rw-r--r-- | samples/bpf/xdp_adjust_tail_user.c | 198 |
1 files changed, 198 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 000000000..ba482dc3d --- /dev/null +++ b/samples/bpf/xdp_adjust_tail_user.c @@ -0,0 +1,198 @@ +/* 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 <net/if.h> +#include <sys/resource.h> +#include <arpa/inet.h> +#include <netinet/ether.h> +#include <unistd.h> +#include <time.h> +#include <bpf/bpf.h> +#include <bpf/libbpf.h> + +#define STATS_INTERVAL_S 2U +#define MAX_PCKT_SIZE 600 + +static int ifindex = -1; +static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST; +static __u32 prog_id; + +static void int_exit(int sig) +{ + __u32 curr_prog_id = 0; + + if (ifindex > -1) { + if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) { + printf("bpf_get_link_xdp_id failed\n"); + exit(1); + } + if (prog_id == curr_prog_id) + bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); + else if (!curr_prog_id) + printf("couldn't find a prog id on a given iface\n"); + else + printf("program on interface changed, not removing\n"); + } + exit(0); +} + +/* simple "icmp packet too big sent" counter + */ +static void poll_stats(unsigned int map_fd, 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, &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 <ifname|ifindex> Interface\n"); + printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n"); + printf(" -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE); + printf(" -S use skb-mode\n"); + printf(" -N enforce native mode\n"); + printf(" -F force loading prog\n"); + printf(" -h Display this help\n"); +} + +int main(int argc, char **argv) +{ + struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; + struct bpf_prog_load_attr prog_load_attr = { + .prog_type = BPF_PROG_TYPE_XDP, + }; + unsigned char opt_flags[256] = {}; + const char *optstr = "i:T:P:SNFh"; + struct bpf_prog_info info = {}; + __u32 info_len = sizeof(info); + unsigned int kill_after_s = 0; + int i, prog_fd, map_fd, opt; + struct bpf_object *obj; + __u32 max_pckt_size = 0; + __u32 key = 0; + char filename[256]; + int err; + + 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 = if_nametoindex(optarg); + if (!ifindex) + ifindex = atoi(optarg); + break; + case 'T': + kill_after_s = atoi(optarg); + break; + case 'P': + max_pckt_size = atoi(optarg); + break; + case 'S': + xdp_flags |= XDP_FLAGS_SKB_MODE; + break; + case 'N': + /* default, set below */ + break; + case 'F': + xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST; + break; + default: + usage(argv[0]); + return 1; + } + opt_flags[opt] = 0; + } + + if (!(xdp_flags & XDP_FLAGS_SKB_MODE)) + xdp_flags |= XDP_FLAGS_DRV_MODE; + + 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; + } + + if (!ifindex) { + fprintf(stderr, "Invalid ifname\n"); + return 1; + } + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + prog_load_attr.file = filename; + + if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd)) + return 1; + + /* static global var 'max_pcktsz' is accessible from .data section */ + if (max_pckt_size) { + map_fd = bpf_object__find_map_fd_by_name(obj, "xdp_adju.data"); + if (map_fd < 0) { + printf("finding a max_pcktsz map in obj file failed\n"); + return 1; + } + bpf_map_update_elem(map_fd, &key, &max_pckt_size, BPF_ANY); + } + + /* fetch icmpcnt map */ + map_fd = bpf_object__find_map_fd_by_name(obj, "icmpcnt"); + if (map_fd < 0) { + printf("finding a icmpcnt map in obj file failed\n"); + return 1; + } + + signal(SIGINT, int_exit); + signal(SIGTERM, int_exit); + + if (bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags) < 0) { + printf("link set xdp fd failed\n"); + return 1; + } + + err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len); + if (err) { + printf("can't get prog info - %s\n", strerror(errno)); + return 1; + } + prog_id = info.id; + + poll_stats(map_fd, kill_after_s); + int_exit(0); + + return 0; +} |