summaryrefslogtreecommitdiff
path: root/net/ipv4/netfilter/iptable_mangle.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/ipv4/netfilter/iptable_mangle.c')
-rw-r--r--net/ipv4/netfilter/iptable_mangle.c260
1 files changed, 260 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/iptable_mangle.c b/net/ipv4/netfilter/iptable_mangle.c
new file mode 100644
index 00000000000..160eb11b6e2
--- /dev/null
+++ b/net/ipv4/netfilter/iptable_mangle.c
@@ -0,0 +1,260 @@
+/*
+ * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
+ *
+ * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
+ * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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.
+ *
+ * Extended to all five netfilter hooks by Brad Chapman & Harald Welte
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/route.h>
+#include <linux/ip.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("iptables mangle table");
+
+#define MANGLE_VALID_HOOKS ((1 << NF_IP_PRE_ROUTING) | \
+ (1 << NF_IP_LOCAL_IN) | \
+ (1 << NF_IP_FORWARD) | \
+ (1 << NF_IP_LOCAL_OUT) | \
+ (1 << NF_IP_POST_ROUTING))
+
+/* Ouch - five different hooks? Maybe this should be a config option..... -- BC */
+static struct
+{
+ struct ipt_replace repl;
+ struct ipt_standard entries[5];
+ struct ipt_error term;
+} initial_table __initdata
+= { { "mangle", MANGLE_VALID_HOOKS, 6,
+ sizeof(struct ipt_standard) * 5 + sizeof(struct ipt_error),
+ { [NF_IP_PRE_ROUTING] = 0,
+ [NF_IP_LOCAL_IN] = sizeof(struct ipt_standard),
+ [NF_IP_FORWARD] = sizeof(struct ipt_standard) * 2,
+ [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 3,
+ [NF_IP_POST_ROUTING] = sizeof(struct ipt_standard) * 4 },
+ { [NF_IP_PRE_ROUTING] = 0,
+ [NF_IP_LOCAL_IN] = sizeof(struct ipt_standard),
+ [NF_IP_FORWARD] = sizeof(struct ipt_standard) * 2,
+ [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 3,
+ [NF_IP_POST_ROUTING] = sizeof(struct ipt_standard) * 4 },
+ 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 }, { } },
+ { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
+ -NF_ACCEPT - 1 } },
+ /* LOCAL_IN */
+ { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
+ 0,
+ sizeof(struct ipt_entry),
+ sizeof(struct ipt_standard),
+ 0, { 0, 0 }, { } },
+ { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
+ -NF_ACCEPT - 1 } },
+ /* FORWARD */
+ { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
+ 0,
+ sizeof(struct ipt_entry),
+ sizeof(struct ipt_standard),
+ 0, { 0, 0 }, { } },
+ { { { { IPT_ALIGN(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 }, { } },
+ { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
+ -NF_ACCEPT - 1 } },
+ /* POST_ROUTING */
+ { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
+ 0,
+ sizeof(struct ipt_entry),
+ sizeof(struct ipt_standard),
+ 0, { 0, 0 }, { } },
+ { { { { IPT_ALIGN(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 }, { } },
+ { { { { IPT_ALIGN(sizeof(struct ipt_error_target)), IPT_ERROR_TARGET } },
+ { } },
+ "ERROR"
+ }
+ }
+};
+
+static struct ipt_table packet_mangler = {
+ .name = "mangle",
+ .valid_hooks = MANGLE_VALID_HOOKS,
+ .lock = RW_LOCK_UNLOCKED,
+ .me = THIS_MODULE,
+};
+
+/* The work comes in here from netfilter.c. */
+static unsigned int
+ipt_route_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_hook(unsigned int hook,
+ struct sk_buff **pskb,
+ const struct net_device *in,
+ const struct net_device *out,
+ int (*okfn)(struct sk_buff *))
+{
+ unsigned int ret;
+ u_int8_t tos;
+ u_int32_t saddr, daddr;
+ unsigned long nfmark;
+
+ /* 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;
+ }
+
+ /* Save things which could affect route */
+ nfmark = (*pskb)->nfmark;
+ saddr = (*pskb)->nh.iph->saddr;
+ daddr = (*pskb)->nh.iph->daddr;
+ tos = (*pskb)->nh.iph->tos;
+
+ ret = ipt_do_table(pskb, hook, in, out, &packet_mangler, NULL);
+ /* Reroute for ANY change. */
+ if (ret != NF_DROP && ret != NF_STOLEN && ret != NF_QUEUE
+ && ((*pskb)->nh.iph->saddr != saddr
+ || (*pskb)->nh.iph->daddr != daddr
+#ifdef CONFIG_IP_ROUTE_FWMARK
+ || (*pskb)->nfmark != nfmark
+#endif
+ || (*pskb)->nh.iph->tos != tos))
+ return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
+
+ return ret;
+}
+
+static struct nf_hook_ops ipt_ops[] = {
+ {
+ .hook = ipt_route_hook,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_IP_PRE_ROUTING,
+ .priority = NF_IP_PRI_MANGLE,
+ },
+ {
+ .hook = ipt_route_hook,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_IP_LOCAL_IN,
+ .priority = NF_IP_PRI_MANGLE,
+ },
+ {
+ .hook = ipt_route_hook,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_IP_FORWARD,
+ .priority = NF_IP_PRI_MANGLE,
+ },
+ {
+ .hook = ipt_local_hook,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_IP_LOCAL_OUT,
+ .priority = NF_IP_PRI_MANGLE,
+ },
+ {
+ .hook = ipt_route_hook,
+ .owner = THIS_MODULE,
+ .pf = PF_INET,
+ .hooknum = NF_IP_POST_ROUTING,
+ .priority = NF_IP_PRI_MANGLE,
+ },
+};
+
+static int __init init(void)
+{
+ int ret;
+
+ /* Register table */
+ ret = ipt_register_table(&packet_mangler, &initial_table.repl);
+ 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;
+
+ ret = nf_register_hook(&ipt_ops[2]);
+ if (ret < 0)
+ goto cleanup_hook1;
+
+ ret = nf_register_hook(&ipt_ops[3]);
+ if (ret < 0)
+ goto cleanup_hook2;
+
+ ret = nf_register_hook(&ipt_ops[4]);
+ if (ret < 0)
+ goto cleanup_hook3;
+
+ return ret;
+
+ cleanup_hook3:
+ nf_unregister_hook(&ipt_ops[3]);
+ cleanup_hook2:
+ nf_unregister_hook(&ipt_ops[2]);
+ cleanup_hook1:
+ nf_unregister_hook(&ipt_ops[1]);
+ 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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-16 15:15:12 +0000