From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willem de Bruijn Subject: [PATCH] utils: bpf_compile Date: Sun, 17 Feb 2013 22:44:01 -0500 Message-ID: <1361159041-9783-1-git-send-email-willemb@google.com> References: <20130123185620.GA6251@1984> Cc: Willem de Bruijn To: pablo@netfilter.org, netfilter-devel@vger.kernel.org Return-path: Received: from mail-ye0-f201.google.com ([209.85.213.201]:51255 "EHLO mail-ye0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754483Ab3BRDoG (ORCPT ); Sun, 17 Feb 2013 22:44:06 -0500 Received: by mail-ye0-f201.google.com with SMTP id r11so533087yen.4 for ; Sun, 17 Feb 2013 19:44:05 -0800 (PST) In-Reply-To: <20130123185620.GA6251@1984> Sender: netfilter-devel-owner@vger.kernel.org List-ID: A BPF compiler to convert tcpudmp expressions to the decimal format accepted by the libxt_bpf. Generate a file and pass that to iptables: bpf_compile RAW 'udp dst port 9000' > test.bpf iptables -A OUTPUT -m bpf --bytecode-file test.bpf -j LOG Or pass the output directly to iptables using backticks: iptables -A INPUT -m bpf --bytecode \ "`./bpf_compile RAW 'udp dst port 9000' | tr '\n' ','`" -j LOG This utility depends on libpcap. The library is only compiled if the option --enable-pcap is explicitly passed to ./configure and libpcap is found. Tested (for review: to be removed before merging): - compilation always succeeds. - utils/bpf_compile is only built when enable_pcap is true and libpcap is found - utils/nfnl_osf is (still) only built when nfnetlink library is found - execution - tested the above two expressions and verified dmesg output - logging - iptables -L INPUT " LOG all -- anywhere anywhere match bpf 48 0 0 0,84 0 0 240,21 0 4 96,48 0 0 6,21 0 13 17,40 0 0 42,21 10 11 9000,48 0 0 0,84 0 0 240,21 0 8 64,48 0 0 9,21 0 6 17,40 0 0 6,69 4 0 8191,177 0 0 0,72 0 0 2,21 0 1 9000,6 0 0 65535,6 0 0 0, LOG level warning " - iptables-save " -A INPUT -m bpf --bytecode "19,48 0 0 0,84 0 0 240,21 0 4 96,48 0 0 6,21 0 13 17,40 0 0 42,21 10 11 9000,48 0 0 0,84 0 0 240,21 0 8 64,48 0 0 9,21 0 6 17,40 0 0 6,69 4 0 8191,177 0 0 0,72 0 0 2,21 0 1 9000,6 0 0 65535,6 0 0 0," -j LOG " --- Makefile.am | 2 -- configure.ac | 8 ++++++++ utils/Makefile.am | 14 ++++++++++++-- utils/bpf_compile.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 75 insertions(+), 4 deletions(-) create mode 100644 utils/bpf_compile.c diff --git a/Makefile.am b/Makefile.am index 6400ba4..c38d360 100644 --- a/Makefile.am +++ b/Makefile.am @@ -10,9 +10,7 @@ endif if ENABLE_LIBIPQ SUBDIRS += libipq endif -if HAVE_LIBNFNETLINK SUBDIRS += utils -endif # Depends on libxtables: SUBDIRS += extensions # Depends on extensions/libext.a: diff --git a/configure.ac b/configure.ac index 27e0b10..fe40afe 100644 --- a/configure.ac +++ b/configure.ac @@ -50,6 +50,9 @@ AC_ARG_ENABLE([devel], [enable_devel="$enableval"], [enable_devel="yes"]) AC_ARG_ENABLE([libipq], AS_HELP_STRING([--enable-libipq], [Build and install libipq])) +AC_ARG_ENABLE([pcap], + AS_HELP_STRING([--enable-pcap], [Build libpcap dependencies]), + [want_pcap="yes"]) AC_ARG_WITH([pkgconfigdir], AS_HELP_STRING([--with-pkgconfigdir=PATH], [Path to the pkgconfig directory [[LIBDIR/pkgconfig]]]), [pkgconfigdir="$withval"], [pkgconfigdir='${libdir}/pkgconfig']) @@ -93,6 +96,11 @@ PKG_CHECK_MODULES([libnfnetlink], [libnfnetlink >= 1.0], [nfnetlink=1], [nfnetlink=0]) AM_CONDITIONAL([HAVE_LIBNFNETLINK], [test "$nfnetlink" = 1]) +if test "$want_pcap" == "yes"; then +AC_CHECK_LIB(pcap, pcap_compile_nopcap, [have_libpcap="yes"]) +fi; +AM_CONDITIONAL([HAVE_LIBPCAP], [test "$have_libpcap" = "yes"]) + regular_CFLAGS="-Wall -Waggregate-return -Wmissing-declarations \ -Wmissing-prototypes -Wredundant-decls -Wshadow -Wstrict-prototypes \ -Winline -pipe"; diff --git a/utils/Makefile.am b/utils/Makefile.am index f1bbfc5..b05ff51 100644 --- a/utils/Makefile.am +++ b/utils/Makefile.am @@ -4,7 +4,17 @@ AM_CFLAGS = ${regular_CFLAGS} AM_CPPFLAGS = ${regular_CPPFLAGS} -I${top_builddir}/include \ -I${top_srcdir}/include ${libnfnetlink_CFLAGS} -sbin_PROGRAMS = nfnl_osf -pkgdata_DATA = pf.os +sbin_PROGRAMS = +pkgdata_DATA = + +if HAVE_LIBNFNETLINK +sbin_PROGRAMS += nfnl_osf +pkgdata_DATA += pf.os nfnl_osf_LDADD = -lnfnetlink +endif + +if HAVE_LIBPCAP +sbin_PROGRAMS += bpf_compile +bpf_compile_LDADD = -lpcap +endif diff --git a/utils/bpf_compile.c b/utils/bpf_compile.c new file mode 100644 index 0000000..7b3e3c0 --- /dev/null +++ b/utils/bpf_compile.c @@ -0,0 +1,55 @@ +/* + * BPF program compilation tool + * + * Generates decimal output, similar to `tcpdump -ddd ...`. + * Unlike tcpdump, will generate for any given link layer type. + * + * There is no makefile: + * compile with `gcc -Wall -o bpf2decimal bpf2decimal.c -lpcap` or similar. + * + * Written by Willem de Bruijn (willemb@google.com) + * Copyright Google, Inc. 2013 + * Licensed under the GNU General Public License version 2 (GPLv2) +*/ + +#include +#include + +int main(int argc, char **argv) +{ + struct bpf_program program; + struct bpf_insn *ins; + int i, dlt = DLT_RAW; + + if (argc < 2 || argc > 3) { + fprintf(stderr, "Usage: %s [link] ''\n\n" + " link is a pcap linklayer type:\n" + " one of EN10MB, RAW, SLIP, ...\n\n" + "Examples: %s RAW 'tcp and greater 100'\n" + " %s EN10MB 'ip proto 47'\n'", + argv[0], argv[0], argv[0]); + return 1; + } + + if (argc == 3) { + dlt = pcap_datalink_name_to_val(argv[1]); + if (dlt == -1) { + fprintf(stderr, "Unknown datalinktype: %s\n", argv[1]); + return 1; + } + } + + if (pcap_compile_nopcap(65535, dlt, &program, argv[argc - 1], 1, + PCAP_NETMASK_UNKNOWN)) { + fprintf(stderr, "Compilation error\n"); + return 1; + } + + printf("%d\n", program.bf_len); + ins = program.bf_insns; + for (i = 0; i < program.bf_len; ++ins, ++i) + printf("%u %u %u %u\n", ins->code, ins->jt, ins->jf, ins->k); + + return 0; +} + -- 1.8.1.3