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_section_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 = bpf_flow_load(&obj, cfg_path_name, cfg_section_name,
29 cfg_map_name, NULL, &prog_fd, NULL);
30 if (ret)
31 error(1, 0, "bpf_flow_load %s", cfg_path_name);
32
33 ret = bpf_prog_attach(prog_fd, 0 /* Ignore */, BPF_FLOW_DISSECTOR, 0);
34 if (ret)
35 error(1, 0, "bpf_prog_attach %s", cfg_path_name);
36
37 ret = bpf_object__pin(obj, cfg_pin_path);
38 if (ret)
39 error(1, 0, "bpf_object__pin %s", cfg_pin_path);
40}
41
42static void detach_program(void)
43{
44 char command[64];
45 int ret;
46
47 ret = bpf_prog_detach(0, BPF_FLOW_DISSECTOR);
48 if (ret)
49 error(1, 0, "bpf_prog_detach");
50
51 /* To unpin, it is necessary and sufficient to just remove this dir */
52 sprintf(command, "rm -r %s", cfg_pin_path);
53 ret = system(command);
54 if (ret)
55 error(1, errno, "%s", command);
56}
57
58static void parse_opts(int argc, char **argv)
59{
60 bool attach = false;
61 bool detach = false;
62 int c;
63
64 while ((c = getopt(argc, argv, "adp:s:")) != -1) {
65 switch (c) {
66 case 'a':
67 if (detach)
68 error(1, 0, "attach/detach are exclusive");
69 attach = true;
70 break;
71 case 'd':
72 if (attach)
73 error(1, 0, "attach/detach are exclusive");
74 detach = true;
75 break;
76 case 'p':
77 if (cfg_path_name)
78 error(1, 0, "only one prog name can be given");
79
80 cfg_path_name = optarg;
81 break;
82 case 's':
83 if (cfg_section_name)
84 error(1, 0, "only one section can be given");
85
86 cfg_section_name = optarg;
87 break;
88 }
89 }
90
91 if (detach)
92 cfg_attach = false;
93
94 if (cfg_attach && !cfg_path_name)
95 error(1, 0, "must provide a path to the BPF program");
96
97 if (cfg_attach && !cfg_section_name)
98 error(1, 0, "must provide a section name");
99}
100
101int main(int argc, char **argv)
102{
103 parse_opts(argc, argv);
104 if (cfg_attach)
105 load_and_attach_program();
106 else
107 detach_program();
108 return 0;
109}