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authorPatrick McHardy <kaber@trash.net>2006-03-20 18:03:40 -0800
committerDavid S. Miller <davem@davemloft.net>2006-03-20 18:03:40 -0800
commitc4b885139203d37f76662c37ae645fe8e0f4e4e5 (patch)
tree5cedf4d632b273df81bf1712b95dbc8b96cdc0e4 /net/netfilter/xt_policy.c
parentf2ffd9eeda82b476c034d733be08ecf6a87d2edf (diff)
[NETFILTER]: x_tables: replace IPv4/IPv6 policy match by address family independant version
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netfilter/xt_policy.c')
-rw-r--r--net/netfilter/xt_policy.c209
1 files changed, 209 insertions, 0 deletions
diff --git a/net/netfilter/xt_policy.c b/net/netfilter/xt_policy.c
new file mode 100644
index 000000000000..1ec22082f04d
--- /dev/null
+++ b/net/netfilter/xt_policy.c
@@ -0,0 +1,209 @@
+/* IP tables module for matching IPsec policy
+ *
+ * Copyright (c) 2004,2005 Patrick McHardy, <kaber@trash.net>
+ *
+ * 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/kernel.h>
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/init.h>
+#include <net/xfrm.h>
+
+#include <linux/netfilter/xt_policy.h>
+#include <linux/netfilter/x_tables.h>
+
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("Xtables IPsec policy matching module");
+MODULE_LICENSE("GPL");
+
+static inline int
+xt_addr_cmp(const union xt_policy_addr *a1, const union xt_policy_addr *m,
+ const union xt_policy_addr *a2, unsigned short family)
+{
+ switch (family) {
+ case AF_INET:
+ return (a1->a4.s_addr ^ a2->a4.s_addr) & m->a4.s_addr;
+ case AF_INET6:
+ return ipv6_masked_addr_cmp(&a1->a6, &m->a6, &a2->a6);
+ }
+ return 0;
+}
+
+static inline int
+match_xfrm_state(struct xfrm_state *x, const struct xt_policy_elem *e,
+ unsigned short family)
+{
+#define MATCH_ADDR(x,y,z) (!e->match.x || \
+ (xt_addr_cmp(&e->x, &e->y, z, family) \
+ ^ e->invert.x))
+#define MATCH(x,y) (!e->match.x || ((e->x == (y)) ^ e->invert.x))
+
+ return MATCH_ADDR(saddr, smask, (union xt_policy_addr *)&x->props.saddr) &&
+ MATCH_ADDR(daddr, dmask, (union xt_policy_addr *)&x->id.daddr.a4) &&
+ MATCH(proto, x->id.proto) &&
+ MATCH(mode, x->props.mode) &&
+ MATCH(spi, x->id.spi) &&
+ MATCH(reqid, x->props.reqid);
+}
+
+static int
+match_policy_in(const struct sk_buff *skb, const struct xt_policy_info *info,
+ unsigned short family)
+{
+ const struct xt_policy_elem *e;
+ struct sec_path *sp = skb->sp;
+ int strict = info->flags & XT_POLICY_MATCH_STRICT;
+ int i, pos;
+
+ if (sp == NULL)
+ return -1;
+ if (strict && info->len != sp->len)
+ return 0;
+
+ for (i = sp->len - 1; i >= 0; i--) {
+ pos = strict ? i - sp->len + 1 : 0;
+ if (pos >= info->len)
+ return 0;
+ e = &info->pol[pos];
+
+ if (match_xfrm_state(sp->x[i].xvec, e, family)) {
+ if (!strict)
+ return 1;
+ } else if (strict)
+ return 0;
+ }
+
+ return strict ? 1 : 0;
+}
+
+static int
+match_policy_out(const struct sk_buff *skb, const struct xt_policy_info *info,
+ unsigned short family)
+{
+ const struct xt_policy_elem *e;
+ struct dst_entry *dst = skb->dst;
+ int strict = info->flags & XT_POLICY_MATCH_STRICT;
+ int i, pos;
+
+ if (dst->xfrm == NULL)
+ return -1;
+
+ for (i = 0; dst && dst->xfrm; dst = dst->child, i++) {
+ pos = strict ? i : 0;
+ if (pos >= info->len)
+ return 0;
+ e = &info->pol[pos];
+
+ if (match_xfrm_state(dst->xfrm, e, family)) {
+ if (!strict)
+ return 1;
+ } else if (strict)
+ return 0;
+ }
+
+ return strict ? i == info->len : 0;
+}
+
+static int match(const struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ const struct xt_match *match,
+ const void *matchinfo,
+ int offset,
+ unsigned int protoff,
+ int *hotdrop)
+{
+ const struct xt_policy_info *info = matchinfo;
+ int ret;
+
+ if (info->flags & XT_POLICY_MATCH_IN)
+ ret = match_policy_in(skb, info, match->family);
+ else
+ ret = match_policy_out(skb, info, match->family);
+
+ if (ret < 0)
+ ret = info->flags & XT_POLICY_MATCH_NONE ? 1 : 0;
+ else if (info->flags & XT_POLICY_MATCH_NONE)
+ ret = 0;
+
+ return ret;
+}
+
+static int checkentry(const char *tablename, const void *ip_void,
+ const struct xt_match *match,
+ void *matchinfo, unsigned int matchsize,
+ unsigned int hook_mask)
+{
+ struct xt_policy_info *info = matchinfo;
+
+ if (!(info->flags & (XT_POLICY_MATCH_IN|XT_POLICY_MATCH_OUT))) {
+ printk(KERN_ERR "xt_policy: neither incoming nor "
+ "outgoing policy selected\n");
+ return 0;
+ }
+ /* hook values are equal for IPv4 and IPv6 */
+ if (hook_mask & (1 << NF_IP_PRE_ROUTING | 1 << NF_IP_LOCAL_IN)
+ && info->flags & XT_POLICY_MATCH_OUT) {
+ printk(KERN_ERR "xt_policy: output policy not valid in "
+ "PRE_ROUTING and INPUT\n");
+ return 0;
+ }
+ if (hook_mask & (1 << NF_IP_POST_ROUTING | 1 << NF_IP_LOCAL_OUT)
+ && info->flags & XT_POLICY_MATCH_IN) {
+ printk(KERN_ERR "xt_policy: input policy not valid in "
+ "POST_ROUTING and OUTPUT\n");
+ return 0;
+ }
+ if (info->len > XT_POLICY_MAX_ELEM) {
+ printk(KERN_ERR "xt_policy: too many policy elements\n");
+ return 0;
+ }
+ return 1;
+}
+
+static struct xt_match policy_match = {
+ .name = "policy",
+ .family = AF_INET,
+ .match = match,
+ .matchsize = sizeof(struct xt_policy_info),
+ .checkentry = checkentry,
+ .me = THIS_MODULE,
+};
+
+static struct xt_match policy6_match = {
+ .name = "policy",
+ .family = AF_INET6,
+ .match = match,
+ .matchsize = sizeof(struct xt_policy_info),
+ .checkentry = checkentry,
+ .me = THIS_MODULE,
+};
+
+static int __init init(void)
+{
+ int ret;
+
+ ret = xt_register_match(AF_INET, &policy_match);
+ if (ret)
+ return ret;
+ ret = xt_register_match(AF_INET6, &policy6_match);
+ if (ret)
+ xt_unregister_match(AF_INET, &policy_match);
+ return ret;
+}
+
+static void __exit fini(void)
+{
+ xt_unregister_match(AF_INET6, &policy6_match);
+ xt_unregister_match(AF_INET, &policy_match);
+}
+
+module_init(init);
+module_exit(fini);
+MODULE_ALIAS("ipt_policy");
+MODULE_ALIAS("ip6t_policy");