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authorJakub Kicinski <jakub.kicinski@netronome.com>2017-10-04 20:10:03 -0700
committerDavid S. Miller <davem@davemloft.net>2017-10-04 21:45:05 -0700
commita92bb546cff0b31d96d5919ebfeda9c678756b42 (patch)
tree74bfc93750a0fe9fce2601edec22f02baa46b562 /tools/bpf/bpf_asm.c
parentc331501c88b64dd1bf83eddcc040441dec187f7e (diff)
downloadlinux-a92bb546cff0b31d96d5919ebfeda9c678756b42.tar.bz2
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 <daniel@iogearbox.net> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools/bpf/bpf_asm.c')
-rw-r--r--tools/bpf/bpf_asm.c52
1 files changed, 52 insertions, 0 deletions
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] <filter-prog file>` 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 <borkmann@redhat.com>
+ * Licensed under the GNU General Public License, version 2.0 (GPLv2)
+ */
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+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;
+}