tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <error.h>
3#include <errno.h>
4#include <getopt.h>
5#include <stdio.h>
6#include <stdlib.h>
7#include <string.h>
8#include <sys/stat.h>
9#include <fcntl.h>
10#include <unistd.h>
11#include <bpf/bpf.h>
12#include <bpf/libbpf.h>
13
14#include "bpf_rlimit.h"
15#include "flow_dissector_load.h"
16
17const char *cfg_pin_path = "/sys/fs/bpf/flow_dissector";
18const char *cfg_map_name = "jmp_table";
19bool cfg_attach = true;
20char *cfg_prog_name;
21char *cfg_path_name;
22
23static void load_and_attach_program(void)
24{
25 int prog_fd, ret;
26 struct bpf_object *obj;
27
28 ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
29 if (ret)
30 error(1, 0, "failed to enable libbpf strict mode: %d", ret);
31
32 ret = bpf_flow_load(&obj, cfg_path_name, cfg_prog_name,
33 cfg_map_name, NULL, &prog_fd, NULL);
34 if (ret)
35 error(1, 0, "bpf_flow_load %s", cfg_path_name);
36
37 ret = bpf_prog_attach(prog_fd, 0 /* Ignore */, BPF_FLOW_DISSECTOR, 0);
38 if (ret)
39 error(1, 0, "bpf_prog_attach %s", cfg_path_name);
40
41 ret = bpf_object__pin(obj, cfg_pin_path);
42 if (ret)
43 error(1, 0, "bpf_object__pin %s", cfg_pin_path);
44}
45
46static void detach_program(void)
47{
48 char command[64];
49 int ret;
50
51 ret = bpf_prog_detach(0, BPF_FLOW_DISSECTOR);
52 if (ret)
53 error(1, 0, "bpf_prog_detach");
54
55 /* To unpin, it is necessary and sufficient to just remove this dir */
56 sprintf(command, "rm -r %s", cfg_pin_path);
57 ret = system(command);
58 if (ret)
59 error(1, errno, "%s", command);
60}
61
62static void parse_opts(int argc, char **argv)
63{
64 bool attach = false;
65 bool detach = false;
66 int c;
67
68 while ((c = getopt(argc, argv, "adp:s:")) != -1) {
69 switch (c) {
70 case 'a':
71 if (detach)
72 error(1, 0, "attach/detach are exclusive");
73 attach = true;
74 break;
75 case 'd':
76 if (attach)
77 error(1, 0, "attach/detach are exclusive");
78 detach = true;
79 break;
80 case 'p':
81 if (cfg_path_name)
82 error(1, 0, "only one path can be given");
83
84 cfg_path_name = optarg;
85 break;
86 case 's':
87 if (cfg_prog_name)
88 error(1, 0, "only one prog can be given");
89
90 cfg_prog_name = optarg;
91 break;
92 }
93 }
94
95 if (detach)
96 cfg_attach = false;
97
98 if (cfg_attach && !cfg_path_name)
99 error(1, 0, "must provide a path to the BPF program");
100
101 if (cfg_attach && !cfg_prog_name)
102 error(1, 0, "must provide a section name");
103}
104
105int main(int argc, char **argv)
106{
107 parse_opts(argc, argv);
108 if (cfg_attach)
109 load_and_attach_program();
110 else
111 detach_program();
112 return 0;
113}