From a92bb546cff0b31d96d5919ebfeda9c678756b42 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 4 Oct 2017 20:10:03 -0700 Subject: tools: rename tools/net directory to tools/bpf We currently only have BPF tools in the tools/net directory. We are about to add more BPF tools there, not necessarily networking related, rename the directory and related Makefile targets to bpf. Suggested-by: Daniel Borkmann Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- tools/bpf/bpf_asm.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 tools/bpf/bpf_asm.c (limited to 'tools/bpf/bpf_asm.c') diff --git a/tools/bpf/bpf_asm.c b/tools/bpf/bpf_asm.c new file mode 100644 index 000000000000..c15aef097b04 --- /dev/null +++ b/tools/bpf/bpf_asm.c @@ -0,0 +1,52 @@ +/* + * Minimal BPF assembler + * + * Instead of libpcap high-level filter expressions, it can be quite + * useful to define filters in low-level BPF assembler (that is kept + * close to Steven McCanne and Van Jacobson's original BPF paper). + * In particular for BPF JIT implementors, JIT security auditors, or + * just for defining BPF expressions that contain extensions which are + * not supported by compilers. + * + * How to get into it: + * + * 1) read Documentation/networking/filter.txt + * 2) Run `bpf_asm [-c] ` to translate into binary + * blob that is loadable with xt_bpf, cls_bpf et al. Note: -c will + * pretty print a C-like construct. + * + * Copyright 2013 Daniel Borkmann + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +#include +#include +#include + +extern void bpf_asm_compile(FILE *fp, bool cstyle); + +int main(int argc, char **argv) +{ + FILE *fp = stdin; + bool cstyle = false; + int i; + + for (i = 1; i < argc; i++) { + if (!strncmp("-c", argv[i], 2)) { + cstyle = true; + continue; + } + + fp = fopen(argv[i], "r"); + if (!fp) { + fp = stdin; + continue; + } + + break; + } + + bpf_asm_compile(fp, cstyle); + + return 0; +} -- cgit v1.2.3