This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / net / ipv4 / netfilter / ipt_policy.c

diff --git a/net/ipv4/netfilter/ipt_policy.c b/net/ipv4/netfilter/ipt_policy.c
new file mode 100644 (file)
index 0000000..5a7a265
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_policy.c
@@ -0,0 +1,176 @@
+/* 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_ipv4.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_policy.h>
+
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("IPtables IPsec policy matching module");
+MODULE_LICENSE("GPL");
+
+
+static inline int
+match_xfrm_state(struct xfrm_state *x, const struct ipt_policy_elem *e)
+{
+#define MATCH_ADDR(x,y,z)      (!e->match.x ||                              \
+                                ((e->x.a4.s_addr == (e->y.a4.s_addr & (z))) \
+                                 ^ e->invert.x))
+#define MATCH(x,y)             (!e->match.x || ((e->x == (y)) ^ e->invert.x))
+
+       return MATCH_ADDR(saddr, smask, x->props.saddr.a4) &&
+              MATCH_ADDR(daddr, dmask, 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 ipt_policy_info *info)
+{
+       const struct ipt_policy_elem *e;
+       struct sec_path *sp = skb->sp;
+       int strict = info->flags & IPT_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)) {
+                       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 ipt_policy_info *info)
+{
+       const struct ipt_policy_elem *e;
+       struct dst_entry *dst = skb->dst;
+       int strict = info->flags & IPT_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)) {
+                       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 void *matchinfo,
+                 int offset,
+                 unsigned int protoff,
+                 int *hotdrop)
+{
+       const struct ipt_policy_info *info = matchinfo;
+       int ret;
+
+       if (info->flags & IPT_POLICY_MATCH_IN)
+               ret = match_policy_in(skb, info);
+       else
+               ret = match_policy_out(skb, info);
+
+       if (ret < 0)
+               ret = info->flags & IPT_POLICY_MATCH_NONE ? 1 : 0;
+       else if (info->flags & IPT_POLICY_MATCH_NONE)
+               ret = 0;
+
+       return ret;
+}
+
+static int checkentry(const char *tablename, const void *ip_void,
+                      void *matchinfo, unsigned int matchsize,
+                      unsigned int hook_mask)
+{
+       struct ipt_policy_info *info = matchinfo;
+
+       if (matchsize != IPT_ALIGN(sizeof(*info))) {
+               printk(KERN_ERR "ipt_policy: matchsize %u != %zu\n",
+                      matchsize, IPT_ALIGN(sizeof(*info)));
+               return 0;
+       }
+       if (!(info->flags & (IPT_POLICY_MATCH_IN|IPT_POLICY_MATCH_OUT))) {
+               printk(KERN_ERR "ipt_policy: neither incoming nor "
+                               "outgoing policy selected\n");
+               return 0;
+       }
+       if (hook_mask & (1 << NF_IP_PRE_ROUTING | 1 << NF_IP_LOCAL_IN)
+           && info->flags & IPT_POLICY_MATCH_OUT) {
+               printk(KERN_ERR "ipt_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 & IPT_POLICY_MATCH_IN) {
+               printk(KERN_ERR "ipt_policy: input policy not valid in "
+                               "POST_ROUTING and OUTPUT\n");
+               return 0;
+       }
+       if (info->len > IPT_POLICY_MAX_ELEM) {
+               printk(KERN_ERR "ipt_policy: too many policy elements\n");
+               return 0;
+       }
+
+       return 1;
+}
+
+static struct ipt_match policy_match = {
+       .name           = "policy",
+       .match          = match,
+       .checkentry     = checkentry,
+       .me             = THIS_MODULE,
+};
+
+static int __init init(void)
+{
+       return ipt_register_match(&policy_match);
+}
+
+static void __exit fini(void)
+{
+       ipt_unregister_match(&policy_match);
+}
+
+module_init(init);
+module_exit(fini);