patch-2.3.99-pre2 linux/net/ipv4/netfilter/iptable_mangle.c

• Lines: 153
• Date: Sat Mar 18 16:51:35 2000
• Orig file: v2.3.99-pre1/linux/net/ipv4/netfilter/iptable_mangle.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.99-pre1/linux/net/ipv4/netfilter/iptable_mangle.c linux/net/ipv4/netfilter/iptable_mangle.c
@@ -0,0 +1,152 @@
+/*
+ * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
+ *
+ * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
+ */
+#include <linux/module.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+#define MANGLE_VALID_HOOKS ((1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_OUT))
+
+/* Standard entry. */
+struct ipt_standard
+{
+	struct ipt_entry entry;
+	struct ipt_standard_target target;
+};
+
+struct ipt_error_target
+{
+	struct ipt_entry_target target;
+	char errorname[IPT_FUNCTION_MAXNAMELEN];
+};
+
+struct ipt_error
+{
+	struct ipt_entry entry;
+	struct ipt_error_target target;
+};
+
+static struct
+{
+	struct ipt_replace repl;
+	struct ipt_standard entries[2];
+	struct ipt_error term;
+} initial_table __initdata
+= { { "mangle", MANGLE_VALID_HOOKS, 3,
+      sizeof(struct ipt_standard) * 2 + sizeof(struct ipt_error),
+      { [NF_IP_PRE_ROUTING] 0,
+	[NF_IP_LOCAL_OUT] sizeof(struct ipt_standard) },
+      { [NF_IP_PRE_ROUTING] 0,
+	[NF_IP_LOCAL_OUT] sizeof(struct ipt_standard) },
+      0, NULL, { } },
+    {
+	    /* PRE_ROUTING */
+	    { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
+		0,
+		sizeof(struct ipt_entry),
+		sizeof(struct ipt_standard),
+		0, { 0, 0 }, { } },
+	      { { sizeof(struct ipt_standard_target), { "" }, { } },
+		-NF_ACCEPT - 1 } },
+	    /* LOCAL_OUT */
+	    { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
+		0,
+		sizeof(struct ipt_entry),
+		sizeof(struct ipt_standard),
+		0, { 0, 0 }, { } },
+	      { { sizeof(struct ipt_standard_target), { "" }, { } },
+		-NF_ACCEPT - 1 } }
+    },
+    /* ERROR */
+    { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
+	0,
+	sizeof(struct ipt_entry),
+	sizeof(struct ipt_error),
+	0, { 0, 0 }, { } },
+      { { sizeof(struct ipt_error_target), { IPT_ERROR_TARGET },
+	  { } },
+	"ERROR"
+      }
+    }
+};
+
+static struct ipt_table packet_mangler
+= { { NULL, NULL }, "mangle", &initial_table.repl,
+    MANGLE_VALID_HOOKS, RW_LOCK_UNLOCKED, NULL };
+
+/* The work comes in here from netfilter.c. */
+static unsigned int
+ipt_hook(unsigned int hook,
+	 struct sk_buff **pskb,
+	 const struct net_device *in,
+	 const struct net_device *out,
+	 int (*okfn)(struct sk_buff *))
+{
+	return ipt_do_table(pskb, hook, in, out, &packet_mangler, NULL);
+}
+
+static unsigned int
+ipt_local_out_hook(unsigned int hook,
+		   struct sk_buff **pskb,
+		   const struct net_device *in,
+		   const struct net_device *out,
+		   int (*okfn)(struct sk_buff *))
+{
+	/* root is playing with raw sockets. */
+	if ((*pskb)->len < sizeof(struct iphdr)
+	    || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
+		if (net_ratelimit())
+			printk("ipt_hook: happy cracking.\n");
+		return NF_ACCEPT;
+	}
+
+	return ipt_do_table(pskb, hook, in, out, &packet_mangler, NULL);
+}
+
+static struct nf_hook_ops ipt_ops[]
+= { { { NULL, NULL }, ipt_hook, PF_INET, NF_IP_PRE_ROUTING, NF_IP_PRI_MANGLE },
+    { { NULL, NULL }, ipt_local_out_hook, PF_INET, NF_IP_LOCAL_OUT,
+		NF_IP_PRI_MANGLE }
+};
+
+static int __init init(void)
+{
+	int ret;
+
+	/* Register table */
+	ret = ipt_register_table(&packet_mangler);
+	if (ret < 0)
+		return ret;
+
+	/* Register hooks */
+	ret = nf_register_hook(&ipt_ops[0]);
+	if (ret < 0)
+		goto cleanup_table;
+
+	ret = nf_register_hook(&ipt_ops[1]);
+	if (ret < 0)
+		goto cleanup_hook0;
+
+	return ret;
+
+ cleanup_hook0:
+	nf_unregister_hook(&ipt_ops[0]);
+ cleanup_table:
+	ipt_unregister_table(&packet_mangler);
+
+	return ret;
+}
+
+static void __exit fini(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < sizeof(ipt_ops)/sizeof(struct nf_hook_ops); i++)
+		nf_unregister_hook(&ipt_ops[i]);
+
+	ipt_unregister_table(&packet_mangler);
+}
+
+module_init(init);
+module_exit(fini);