1 files changed, 156 insertions, 0 deletions
diff --git a/kernel/linux/net/bridge/netfilter/ebtable_nat.c b/kernel/linux/net/bridge/netfilter/ebtable_nat.c
new file mode 100644
index 0000000..b99db09
--- /dev/null
+++ b/kernel/linux/net/bridge/netfilter/ebtable_nat.c
@@ -0,0 +1,156 @@
+/*
+ *  ebtable_nat
+ *
+ *	Authors:
+ *	Bart De Schuymer <bart.de.schuymer@pandora.be>
+ *
+ *  April, 2002
+ *
+ */
+
+#include <linux/netfilter_bridge/ebtables.h>
+#include <linux/netfilter_bridge.h>
+#include <linux/netdevice.h>
+#include <linux/module.h>
+#define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \
+   (1 << NF_BR_POST_ROUTING))
+
+static struct ebt_entries initial_chains[] =
+{
+  {0, EBT_ACCEPT, 0},
+  {0, EBT_ACCEPT, 0},
+  {0, EBT_ACCEPT, 0}
+};
+
+static struct ebt_replace initial_table =
+{
+  "nat", NAT_VALID_HOOKS, 0, 3 * sizeof(struct ebt_entries),
+  { [NF_BR_PRE_ROUTING]&initial_chains[0], [NF_BR_LOCAL_OUT]&initial_chains[1],
+    [NF_BR_POST_ROUTING]&initial_chains[2] }, {},
+  0, NULL, (char *)initial_chains
+};
+
+static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
+{
+	if (valid_hooks & ~NAT_VALID_HOOKS)
+		return -EINVAL;
+	return 0;
+}
+
+static struct ebt_table frame_nat =
+{
+  {NULL, NULL}, "nat", &initial_table, NAT_VALID_HOOKS,
+  RW_LOCK_UNLOCKED, check, NULL
+};
+
+// used for snat to know if the frame comes from FORWARD or LOCAL_OUT.
+// needed because of the bridge-nf patch (that allows use of iptables
+// on bridged traffic)
+// if the packet is routed, we want the ebtables stuff on POSTROUTING
+// to be executed _after_ the iptables stuff. when it's bridged, it's
+// the way around
+static struct net_device __fake_net_device = {
+        hard_header_len:        ETH_HLEN
+};
+
+static unsigned int
+ebt_nat_dst (unsigned int hook, struct sk_buff **pskb,
+   const struct net_device *in, const struct net_device *out,
+   int (*okfn)(struct sk_buff *))
+{
+	return ebt_do_table(hook, pskb, in, out, &frame_nat);
+}
+
+// let snat know this frame is routed
+static unsigned int ebt_clear_physin (unsigned int hook, struct sk_buff **pskb,
+   const struct net_device *in, const struct net_device *out,
+   int (*okfn)(struct sk_buff *))
+{
+	(*pskb)->physindev = NULL;
+	return NF_ACCEPT;
+}
+
+// let snat know this frame is bridged
+static unsigned int ebt_set_physin (unsigned int hook, struct sk_buff **pskb,
+   const struct net_device *in, const struct net_device *out,
+   int (*okfn)(struct sk_buff *))
+{
+	(*pskb)->physindev = &__fake_net_device;
+	return NF_ACCEPT;
+}
+
+static unsigned int ebt_nat_src (unsigned int hook, struct sk_buff **pskb,
+			const struct net_device *in,
+			const struct net_device *out,
+			int (*okfn)(struct sk_buff *))
+{
+	// this is a routed packet
+	if ((*pskb)->physindev == NULL)
+		return NF_ACCEPT;
+	if ((*pskb)->physindev != &__fake_net_device)
+		printk("ebtables (br_nat_src): physindev hack "
+		       "doesn't work - BUG\n");
+
+	return ebt_do_table(hook, pskb, in, out, &frame_nat);
+}
+
+static unsigned int ebt_nat_src_route (unsigned int hook, struct sk_buff **pskb,
+   const struct net_device *in, const struct net_device *out,
+   int (*okfn)(struct sk_buff *))
+{
+	// this is a bridged packet
+	if ((*pskb)->physindev == &__fake_net_device)
+		return NF_ACCEPT;
+	if ((*pskb)->physindev)
+		printk("ebtables (br_nat_src_route): physindev hack "
+		       "doesn't work - BUG\n");
+
+	return ebt_do_table(hook, pskb, in, out, &frame_nat);
+}
+
+static struct nf_hook_ops ebt_ops_nat[] = {
+	{ { NULL, NULL }, ebt_nat_dst, PF_BRIDGE, NF_BR_LOCAL_OUT,
+	   NF_BR_PRI_NAT_DST_OTHER},
+	{ { NULL, NULL }, ebt_nat_src, PF_BRIDGE, NF_BR_POST_ROUTING,
+	   NF_BR_PRI_NAT_SRC_BRIDGED},
+	{ { NULL, NULL }, ebt_nat_src_route, PF_BRIDGE, NF_BR_POST_ROUTING,
+	   NF_BR_PRI_NAT_SRC_OTHER},
+	{ { NULL, NULL }, ebt_nat_dst, PF_BRIDGE, NF_BR_PRE_ROUTING,
+	   NF_BR_PRI_NAT_DST_BRIDGED},
+	{ { NULL, NULL }, ebt_clear_physin, PF_BRIDGE, NF_BR_LOCAL_OUT,
+	   NF_BR_PRI_FILTER_OTHER + 1},
+	{ { NULL, NULL }, ebt_set_physin, PF_BRIDGE, NF_BR_FORWARD,
+	   NF_BR_PRI_FILTER_OTHER + 1}
+};
+
+static int __init init(void)
+{
+	int i, ret, j;
+
+	ret = ebt_register_table(&frame_nat);
+	if (ret < 0)
+		return ret;
+	for (i = 0; i < sizeof(ebt_ops_nat) / sizeof(ebt_ops_nat[0]); i++)
+		if ((ret = nf_register_hook(&ebt_ops_nat[i])) < 0)
+			goto cleanup;
+	return ret;
+cleanup:
+	for (j = 0; j < i; j++)
+		nf_unregister_hook(&ebt_ops_nat[j]);
+	ebt_unregister_table(&frame_nat);
+	return ret;
+}
+
+static void __exit fini(void)
+{
+	int i;
+
+	for (i = 0; i < sizeof(ebt_ops_nat) / sizeof(ebt_ops_nat[0]); i++)
+		nf_unregister_hook(&ebt_ops_nat[i]);
+	ebt_unregister_table(&frame_nat);
+}
+
+module_init(init);
+module_exit(fini);
+EXPORT_NO_SYMBOLS;
+MODULE_LICENSE("GPL");