472 lines
11 KiB
C
472 lines
11 KiB
C
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// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause
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/* Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */
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#include <stdnoreturn.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <getopt.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include <net/if.h>
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#include <linux/if_link.h>
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#include <linux/limits.h>
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static unsigned int ifindex;
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static __u32 attached_prog_id;
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static bool attached_tc;
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static void noreturn cleanup(int sig)
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{
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LIBBPF_OPTS(bpf_xdp_attach_opts, opts);
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int prog_fd;
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int err;
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if (attached_prog_id == 0)
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exit(0);
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if (attached_tc) {
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LIBBPF_OPTS(bpf_tc_hook, hook,
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.ifindex = ifindex,
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.attach_point = BPF_TC_INGRESS);
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err = bpf_tc_hook_destroy(&hook);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_tc_hook_destroy: %s\n", strerror(-err));
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fprintf(stderr, "Failed to destroy the TC hook\n");
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exit(1);
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}
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exit(0);
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}
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prog_fd = bpf_prog_get_fd_by_id(attached_prog_id);
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if (prog_fd < 0) {
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fprintf(stderr, "Error: bpf_prog_get_fd_by_id: %s\n", strerror(-prog_fd));
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err = bpf_xdp_attach(ifindex, -1, 0, NULL);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_set_link_xdp_fd: %s\n", strerror(-err));
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fprintf(stderr, "Failed to detach XDP program\n");
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exit(1);
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}
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} else {
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opts.old_prog_fd = prog_fd;
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err = bpf_xdp_attach(ifindex, -1, XDP_FLAGS_REPLACE, &opts);
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close(prog_fd);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_set_link_xdp_fd_opts: %s\n", strerror(-err));
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/* Not an error if already replaced by someone else. */
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if (err != -EEXIST) {
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fprintf(stderr, "Failed to detach XDP program\n");
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exit(1);
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}
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}
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}
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exit(0);
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}
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static noreturn void usage(const char *progname)
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{
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fprintf(stderr, "Usage: %s [--iface <iface>|--prog <prog_id>] [--mss4 <mss ipv4> --mss6 <mss ipv6> --wscale <wscale> --ttl <ttl>] [--ports <port1>,<port2>,...] [--single] [--tc]\n",
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progname);
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exit(1);
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}
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static unsigned long parse_arg_ul(const char *progname, const char *arg, unsigned long limit)
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{
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unsigned long res;
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char *endptr;
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errno = 0;
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res = strtoul(arg, &endptr, 10);
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if (errno != 0 || *endptr != '\0' || arg[0] == '\0' || res > limit)
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usage(progname);
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return res;
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}
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static void parse_options(int argc, char *argv[], unsigned int *ifindex, __u32 *prog_id,
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__u64 *tcpipopts, char **ports, bool *single, bool *tc)
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{
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static struct option long_options[] = {
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{ "help", no_argument, NULL, 'h' },
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{ "iface", required_argument, NULL, 'i' },
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{ "prog", required_argument, NULL, 'x' },
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{ "mss4", required_argument, NULL, 4 },
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{ "mss6", required_argument, NULL, 6 },
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{ "wscale", required_argument, NULL, 'w' },
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{ "ttl", required_argument, NULL, 't' },
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{ "ports", required_argument, NULL, 'p' },
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{ "single", no_argument, NULL, 's' },
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{ "tc", no_argument, NULL, 'c' },
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{ NULL, 0, NULL, 0 },
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};
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unsigned long mss4, wscale, ttl;
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unsigned long long mss6;
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unsigned int tcpipopts_mask = 0;
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if (argc < 2)
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usage(argv[0]);
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*ifindex = 0;
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*prog_id = 0;
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*tcpipopts = 0;
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*ports = NULL;
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*single = false;
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*tc = false;
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while (true) {
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int opt;
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opt = getopt_long(argc, argv, "", long_options, NULL);
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if (opt == -1)
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break;
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switch (opt) {
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case 'h':
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usage(argv[0]);
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break;
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case 'i':
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*ifindex = if_nametoindex(optarg);
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if (*ifindex == 0)
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usage(argv[0]);
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break;
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case 'x':
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*prog_id = parse_arg_ul(argv[0], optarg, UINT32_MAX);
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if (*prog_id == 0)
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usage(argv[0]);
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break;
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case 4:
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mss4 = parse_arg_ul(argv[0], optarg, UINT16_MAX);
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tcpipopts_mask |= 1 << 0;
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break;
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case 6:
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mss6 = parse_arg_ul(argv[0], optarg, UINT16_MAX);
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tcpipopts_mask |= 1 << 1;
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break;
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case 'w':
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wscale = parse_arg_ul(argv[0], optarg, 14);
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tcpipopts_mask |= 1 << 2;
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break;
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case 't':
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ttl = parse_arg_ul(argv[0], optarg, UINT8_MAX);
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tcpipopts_mask |= 1 << 3;
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break;
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case 'p':
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*ports = optarg;
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break;
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case 's':
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*single = true;
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break;
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case 'c':
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*tc = true;
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break;
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default:
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usage(argv[0]);
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}
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}
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if (optind < argc)
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usage(argv[0]);
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if (tcpipopts_mask == 0xf) {
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if (mss4 == 0 || mss6 == 0 || wscale == 0 || ttl == 0)
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usage(argv[0]);
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*tcpipopts = (mss6 << 32) | (ttl << 24) | (wscale << 16) | mss4;
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} else if (tcpipopts_mask != 0) {
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usage(argv[0]);
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}
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if (*ifindex != 0 && *prog_id != 0)
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usage(argv[0]);
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if (*ifindex == 0 && *prog_id == 0)
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usage(argv[0]);
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}
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static int syncookie_attach(const char *argv0, unsigned int ifindex, bool tc)
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{
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struct bpf_prog_info info = {};
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__u32 info_len = sizeof(info);
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char xdp_filename[PATH_MAX];
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struct bpf_program *prog;
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struct bpf_object *obj;
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int prog_fd;
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int err;
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snprintf(xdp_filename, sizeof(xdp_filename), "%s_kern.bpf.o", argv0);
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obj = bpf_object__open_file(xdp_filename, NULL);
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err = libbpf_get_error(obj);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_object__open_file: %s\n", strerror(-err));
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return err;
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}
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err = bpf_object__load(obj);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_object__open_file: %s\n", strerror(-err));
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return err;
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}
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prog = bpf_object__find_program_by_name(obj, tc ? "syncookie_tc" : "syncookie_xdp");
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if (!prog) {
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fprintf(stderr, "Error: bpf_object__find_program_by_name: program was not found\n");
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return -ENOENT;
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}
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prog_fd = bpf_program__fd(prog);
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err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_prog_get_info_by_fd: %s\n",
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strerror(-err));
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goto out;
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}
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attached_tc = tc;
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attached_prog_id = info.id;
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signal(SIGINT, cleanup);
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signal(SIGTERM, cleanup);
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if (tc) {
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LIBBPF_OPTS(bpf_tc_hook, hook,
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.ifindex = ifindex,
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.attach_point = BPF_TC_INGRESS);
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LIBBPF_OPTS(bpf_tc_opts, opts,
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.handle = 1,
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.priority = 1,
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.prog_fd = prog_fd);
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err = bpf_tc_hook_create(&hook);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_tc_hook_create: %s\n",
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strerror(-err));
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goto fail;
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}
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err = bpf_tc_attach(&hook, &opts);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_tc_attach: %s\n",
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strerror(-err));
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goto fail;
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}
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} else {
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err = bpf_xdp_attach(ifindex, prog_fd,
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XDP_FLAGS_UPDATE_IF_NOEXIST, NULL);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_set_link_xdp_fd: %s\n",
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strerror(-err));
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goto fail;
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}
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}
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err = 0;
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out:
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bpf_object__close(obj);
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return err;
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fail:
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signal(SIGINT, SIG_DFL);
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signal(SIGTERM, SIG_DFL);
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attached_prog_id = 0;
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goto out;
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}
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static int syncookie_open_bpf_maps(__u32 prog_id, int *values_map_fd, int *ports_map_fd)
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{
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struct bpf_prog_info prog_info;
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__u32 map_ids[8];
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__u32 info_len;
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int prog_fd;
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int err;
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int i;
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*values_map_fd = -1;
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*ports_map_fd = -1;
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prog_fd = bpf_prog_get_fd_by_id(prog_id);
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if (prog_fd < 0) {
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fprintf(stderr, "Error: bpf_prog_get_fd_by_id: %s\n", strerror(-prog_fd));
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return prog_fd;
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}
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prog_info = (struct bpf_prog_info) {
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.nr_map_ids = 8,
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.map_ids = (__u64)(unsigned long)map_ids,
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};
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info_len = sizeof(prog_info);
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err = bpf_prog_get_info_by_fd(prog_fd, &prog_info, &info_len);
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if (err != 0) {
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fprintf(stderr, "Error: bpf_prog_get_info_by_fd: %s\n",
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strerror(-err));
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goto out;
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}
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if (prog_info.nr_map_ids < 2) {
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fprintf(stderr, "Error: Found %u BPF maps, expected at least 2\n",
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prog_info.nr_map_ids);
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err = -ENOENT;
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goto out;
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}
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for (i = 0; i < prog_info.nr_map_ids; i++) {
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struct bpf_map_info map_info = {};
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int map_fd;
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err = bpf_map_get_fd_by_id(map_ids[i]);
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if (err < 0) {
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fprintf(stderr, "Error: bpf_map_get_fd_by_id: %s\n", strerror(-err));
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goto err_close_map_fds;
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}
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map_fd = err;
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info_len = sizeof(map_info);
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err = bpf_map_get_info_by_fd(map_fd, &map_info, &info_len);
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if (err != 0) {
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fprintf(stderr, "Error: bpf_map_get_info_by_fd: %s\n",
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strerror(-err));
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close(map_fd);
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goto err_close_map_fds;
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}
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if (strcmp(map_info.name, "values") == 0) {
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*values_map_fd = map_fd;
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continue;
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}
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if (strcmp(map_info.name, "allowed_ports") == 0) {
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*ports_map_fd = map_fd;
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continue;
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}
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close(map_fd);
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}
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if (*values_map_fd != -1 && *ports_map_fd != -1) {
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err = 0;
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goto out;
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}
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err = -ENOENT;
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err_close_map_fds:
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if (*values_map_fd != -1)
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close(*values_map_fd);
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if (*ports_map_fd != -1)
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close(*ports_map_fd);
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*values_map_fd = -1;
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*ports_map_fd = -1;
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out:
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close(prog_fd);
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return err;
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}
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int main(int argc, char *argv[])
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{
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int values_map_fd, ports_map_fd;
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__u64 tcpipopts;
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bool firstiter;
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__u64 prevcnt;
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__u32 prog_id;
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char *ports;
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bool single;
|
||
|
|
int err = 0;
|
||
|
|
bool tc;
|
||
|
|
|
||
|
|
parse_options(argc, argv, &ifindex, &prog_id, &tcpipopts, &ports,
|
||
|
|
&single, &tc);
|
||
|
|
|
||
|
|
if (prog_id == 0) {
|
||
|
|
if (!tc) {
|
||
|
|
err = bpf_xdp_query_id(ifindex, 0, &prog_id);
|
||
|
|
if (err < 0) {
|
||
|
|
fprintf(stderr, "Error: bpf_get_link_xdp_id: %s\n",
|
||
|
|
strerror(-err));
|
||
|
|
goto out;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (prog_id == 0) {
|
||
|
|
err = syncookie_attach(argv[0], ifindex, tc);
|
||
|
|
if (err < 0)
|
||
|
|
goto out;
|
||
|
|
prog_id = attached_prog_id;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
err = syncookie_open_bpf_maps(prog_id, &values_map_fd, &ports_map_fd);
|
||
|
|
if (err < 0)
|
||
|
|
goto out;
|
||
|
|
|
||
|
|
if (ports) {
|
||
|
|
__u16 port_last = 0;
|
||
|
|
__u32 port_idx = 0;
|
||
|
|
char *p = ports;
|
||
|
|
|
||
|
|
fprintf(stderr, "Replacing allowed ports\n");
|
||
|
|
|
||
|
|
while (p && *p != '\0') {
|
||
|
|
char *token = strsep(&p, ",");
|
||
|
|
__u16 port;
|
||
|
|
|
||
|
|
port = parse_arg_ul(argv[0], token, UINT16_MAX);
|
||
|
|
err = bpf_map_update_elem(ports_map_fd, &port_idx, &port, BPF_ANY);
|
||
|
|
if (err != 0) {
|
||
|
|
fprintf(stderr, "Error: bpf_map_update_elem: %s\n", strerror(-err));
|
||
|
|
fprintf(stderr, "Failed to add port %u (index %u)\n",
|
||
|
|
port, port_idx);
|
||
|
|
goto out_close_maps;
|
||
|
|
}
|
||
|
|
fprintf(stderr, "Added port %u\n", port);
|
||
|
|
port_idx++;
|
||
|
|
}
|
||
|
|
err = bpf_map_update_elem(ports_map_fd, &port_idx, &port_last, BPF_ANY);
|
||
|
|
if (err != 0) {
|
||
|
|
fprintf(stderr, "Error: bpf_map_update_elem: %s\n", strerror(-err));
|
||
|
|
fprintf(stderr, "Failed to add the terminator value 0 (index %u)\n",
|
||
|
|
port_idx);
|
||
|
|
goto out_close_maps;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (tcpipopts) {
|
||
|
|
__u32 key = 0;
|
||
|
|
|
||
|
|
fprintf(stderr, "Replacing TCP/IP options\n");
|
||
|
|
|
||
|
|
err = bpf_map_update_elem(values_map_fd, &key, &tcpipopts, BPF_ANY);
|
||
|
|
if (err != 0) {
|
||
|
|
fprintf(stderr, "Error: bpf_map_update_elem: %s\n", strerror(-err));
|
||
|
|
goto out_close_maps;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if ((ports || tcpipopts) && attached_prog_id == 0 && !single)
|
||
|
|
goto out_close_maps;
|
||
|
|
|
||
|
|
prevcnt = 0;
|
||
|
|
firstiter = true;
|
||
|
|
while (true) {
|
||
|
|
__u32 key = 1;
|
||
|
|
__u64 value;
|
||
|
|
|
||
|
|
err = bpf_map_lookup_elem(values_map_fd, &key, &value);
|
||
|
|
if (err != 0) {
|
||
|
|
fprintf(stderr, "Error: bpf_map_lookup_elem: %s\n", strerror(-err));
|
||
|
|
goto out_close_maps;
|
||
|
|
}
|
||
|
|
if (firstiter) {
|
||
|
|
prevcnt = value;
|
||
|
|
firstiter = false;
|
||
|
|
}
|
||
|
|
if (single) {
|
||
|
|
printf("Total SYNACKs generated: %llu\n", value);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
printf("SYNACKs generated: %llu (total %llu)\n", value - prevcnt, value);
|
||
|
|
prevcnt = value;
|
||
|
|
sleep(1);
|
||
|
|
}
|
||
|
|
|
||
|
|
out_close_maps:
|
||
|
|
close(values_map_fd);
|
||
|
|
close(ports_map_fd);
|
||
|
|
out:
|
||
|
|
return err == 0 ? 0 : 1;
|
||
|
|
}
|