new file mode 100644
@@ -0,0 +1 @@
+CONFIG_NETFILTER_XT_MATCH_BPF=m
new file mode 100644
@@ -0,0 +1,17 @@
+#ifndef _XT_BPF_H
+#define _XT_BPF_H
+
+#include <linux/filter.h>
+#include <linux/types.h>
+
+#define XT_BPF_MAX_NUM_INSTR 64
+
+struct xt_bpf_info {
+ __u16 bpf_program_num_elem;
+ struct sock_filter bpf_program[XT_BPF_MAX_NUM_INSTR];
+
+ /* only used in the kernel */
+ struct sk_filter *filter __attribute__((aligned(8)));
+};
+
+#endif /*_XT_BPF_H */
@@ -798,6 +798,15 @@ config NETFILTER_XT_MATCH_ADDRTYPE
If you want to compile it as a module, say M here and read
<file:Documentation/kbuild/modules.txt>. If unsure, say `N'.
+config NETFILTER_XT_MATCH_BPF
+ tristate '"bpf" match support'
+ depends on NETFILTER_ADVANCED
+ help
+ BPF matching applies a linux socket filter to each packet and
+ accepts those for which the filter returns non-zero.
+
+ To compile it as a module, choose M here. If unsure, say N.
+
config NETFILTER_XT_MATCH_CLUSTER
tristate '"cluster" match support'
depends on NF_CONNTRACK
@@ -98,6 +98,7 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_IDLETIMER) += xt_IDLETIMER.o
# matches
obj-$(CONFIG_NETFILTER_XT_MATCH_ADDRTYPE) += xt_addrtype.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_BPF) += xt_bpf.o
obj-$(CONFIG_NETFILTER_XT_MATCH_CLUSTER) += xt_cluster.o
obj-$(CONFIG_NETFILTER_XT_MATCH_COMMENT) += xt_comment.o
obj-$(CONFIG_NETFILTER_XT_MATCH_CONNBYTES) += xt_connbytes.o
@@ -379,8 +379,9 @@ int xt_check_match(struct xt_mtchk_param *par,
if (XT_ALIGN(par->match->matchsize) != size &&
par->match->matchsize != -1) {
/*
- * ebt_among is exempt from centralized matchsize checking
- * because it uses a dynamic-size data set.
+ * matches of variable size length, such as ebt_among,
+ * are exempt from centralized matchsize checking. They
+ * skip the test by setting xt_match.matchsize to -1.
*/
pr_err("%s_tables: %s.%u match: invalid size "
"%u (kernel) != (user) %u\n",
new file mode 100644
@@ -0,0 +1,73 @@
+/* Xtables module to match packets using a BPF filter.
+ * Copyright 2013 Google Inc.
+ * Written by Willem de Bruijn <willemb@google.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ipv6.h>
+#include <linux/filter.h>
+#include <net/ip.h>
+
+#include <linux/netfilter/xt_bpf.h>
+#include <linux/netfilter/x_tables.h>
+
+MODULE_AUTHOR("Willem de Bruijn <willemb@google.com>");
+MODULE_DESCRIPTION("Xtables: BPF filter match");
+MODULE_LICENSE("GPL");
+
+static int bpf_mt_check(const struct xt_mtchk_param *par)
+{
+ struct xt_bpf_info *info = par->matchinfo;
+ struct sock_fprog program;
+
+ program.len = info->bpf_program_num_elem;
+ program.filter = info->bpf_program;
+ if (sk_unattached_filter_create(&info->filter, &program)) {
+ pr_info("bpf: check failed: parse error\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static bool bpf_mt(const struct sk_buff *skb, struct xt_action_param *par)
+{
+ const struct xt_bpf_info *info = par->matchinfo;
+
+ return SK_RUN_FILTER(info->filter, skb);
+}
+
+static void bpf_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_bpf_info *info = par->matchinfo;
+ sk_unattached_filter_destroy(info->filter);
+}
+
+static struct xt_match bpf_mt_reg __read_mostly = {
+ .name = "bpf",
+ .revision = 0,
+ .family = NFPROTO_UNSPEC,
+ .checkentry = bpf_mt_check,
+ .match = bpf_mt,
+ .destroy = bpf_mt_destroy,
+ .matchsize = sizeof(struct xt_bpf_info),
+ .me = THIS_MODULE,
+};
+
+static int __init bpf_mt_init(void)
+{
+ return xt_register_match(&bpf_mt_reg);
+}
+
+static void __exit bpf_mt_exit(void)
+{
+ xt_unregister_match(&bpf_mt_reg);
+}
+
+module_init(bpf_mt_init);
+module_exit(bpf_mt_exit);