Commit | Line | Data |
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3f356385 DB |
1 | /* |
2 | * Minimal BPF assembler | |
3 | * | |
4 | * Instead of libpcap high-level filter expressions, it can be quite | |
5 | * useful to define filters in low-level BPF assembler (that is kept | |
6 | * close to Steven McCanne and Van Jacobson's original BPF paper). | |
7 | * In particular for BPF JIT implementors, JIT security auditors, or | |
8 | * just for defining BPF expressions that contain extensions which are | |
9 | * not supported by compilers. | |
10 | * | |
11 | * How to get into it: | |
12 | * | |
13 | * 1) read Documentation/networking/filter.txt | |
14 | * 2) Run `bpf_asm [-c] <filter-prog file>` to translate into binary | |
15 | * blob that is loadable with xt_bpf, cls_bpf et al. Note: -c will | |
16 | * pretty print a C-like construct. | |
17 | * | |
18 | * Copyright 2013 Daniel Borkmann <borkmann@redhat.com> | |
19 | * Licensed under the GNU General Public License, version 2.0 (GPLv2) | |
20 | */ | |
21 | ||
22 | #include <stdbool.h> | |
23 | #include <stdio.h> | |
24 | #include <string.h> | |
25 | ||
26 | extern void bpf_asm_compile(FILE *fp, bool cstyle); | |
27 | ||
28 | int main(int argc, char **argv) | |
29 | { | |
30 | FILE *fp = stdin; | |
31 | bool cstyle = false; | |
32 | int i; | |
33 | ||
34 | for (i = 1; i < argc; i++) { | |
35 | if (!strncmp("-c", argv[i], 2)) { | |
36 | cstyle = true; | |
37 | continue; | |
38 | } | |
39 | ||
40 | fp = fopen(argv[i], "r"); | |
41 | if (!fp) { | |
42 | fp = stdin; | |
43 | continue; | |
44 | } | |
45 | ||
46 | break; | |
47 | } | |
48 | ||
49 | bpf_asm_compile(fp, cstyle); | |
50 | ||
51 | return 0; | |
52 | } |