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-rw-r--r--samples/bpf/xdp_adjust_tail_user.c198
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 0000000000..e9426bd654
--- /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 <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_xdp_query_id(ifindex, xdp_flags, &curr_prog_id)) {
+ printf("bpf_xdp_query_id failed\n");
+ exit(1);
+ }
+ if (prog_id == curr_prog_id)
+ bpf_xdp_detach(ifindex, xdp_flags, NULL);
+ 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)
+{
+ 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_program *prog;
+ 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 (!ifindex) {
+ fprintf(stderr, "Invalid ifname\n");
+ return 1;
+ }
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+ obj = bpf_object__open_file(filename, NULL);
+ if (libbpf_get_error(obj))
+ return 1;
+
+ prog = bpf_object__next_program(obj, NULL);
+ bpf_program__set_type(prog, BPF_PROG_TYPE_XDP);
+
+ err = bpf_object__load(obj);
+ if (err)
+ return 1;
+
+ prog_fd = bpf_program__fd(prog);
+
+ /* 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_xdp_attach(ifindex, prog_fd, xdp_flags, NULL) < 0) {
+ printf("link set xdp fd failed\n");
+ return 1;
+ }
+
+ err = bpf_prog_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;
+}