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 "flow_dissector_load.h"
15
16 const char *cfg_pin_path = "/sys/fs/bpf/flow_dissector";
17 const char *cfg_map_name = "jmp_table";
18 bool cfg_attach = true;
19 char *cfg_prog_name;
20 char *cfg_path_name;
21
22 static void load_and_attach_program(void)
23 {
24 int prog_fd, ret;
25 struct bpf_object *obj;
26
27 /* Use libbpf 1.0 API mode */
28 libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
29
30 ret = bpf_flow_load(&obj, cfg_path_name, cfg_prog_name,
31 cfg_map_name, NULL, &prog_fd, NULL);
32 if (ret)
33 error(1, 0, "bpf_flow_load %s", cfg_path_name);
34
35 ret = bpf_prog_attach(prog_fd, 0 /* Ignore */, BPF_FLOW_DISSECTOR, 0);
36 if (ret)
37 error(1, 0, "bpf_prog_attach %s", cfg_path_name);
38
39 ret = bpf_object__pin(obj, cfg_pin_path);
40 if (ret)
41 error(1, 0, "bpf_object__pin %s", cfg_pin_path);
42 }
43
44 static void detach_program(void)
45 {
46 char command[64];
47 int ret;
48
49 ret = bpf_prog_detach(0, BPF_FLOW_DISSECTOR);
50 if (ret)
51 error(1, 0, "bpf_prog_detach");
52
53 /* To unpin, it is necessary and sufficient to just remove this dir */
54 sprintf(command, "rm -r %s", cfg_pin_path);
55 ret = system(command);
56 if (ret)
57 error(1, errno, "%s", command);
58 }
59
60 static void parse_opts(int argc, char **argv)
61 {
62 bool attach = false;
63 bool detach = false;
64 int c;
65
66 while ((c = getopt(argc, argv, "adp:s:")) != -1) {
67 switch (c) {
68 case 'a':
69 if (detach)
70 error(1, 0, "attach/detach are exclusive");
71 attach = true;
72 break;
73 case 'd':
74 if (attach)
75 error(1, 0, "attach/detach are exclusive");
76 detach = true;
77 break;
78 case 'p':
79 if (cfg_path_name)
80 error(1, 0, "only one path can be given");
81
82 cfg_path_name = optarg;
83 break;
84 case 's':
85 if (cfg_prog_name)
86 error(1, 0, "only one prog can be given");
87
88 cfg_prog_name = optarg;
89 break;
90 }
91 }
92
93 if (detach)
94 cfg_attach = false;
95
96 if (cfg_attach && !cfg_path_name)
97 error(1, 0, "must provide a path to the BPF program");
98
99 if (cfg_attach && !cfg_prog_name)
100 error(1, 0, "must provide a section name");
101 }
102
103 int main(int argc, char **argv)
104 {
105 parse_opts(argc, argv);
106 if (cfg_attach)
107 load_and_attach_program();
108 else
109 detach_program();
110 return 0;
111 }
112
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