patch-2.3.99-pre2 linux/net/ipv4/netfilter/ipt_MASQUERADE.c
Next file: linux/net/ipv4/netfilter/ipt_MIRROR.c
Previous file: linux/net/ipv4/netfilter/ipt_MARK.c
Back to the patch index
Back to the overall index
- Lines: 172
- Date:
Fri Mar 17 10:56:20 2000
- Orig file:
v2.3.99-pre1/linux/net/ipv4/netfilter/ipt_MASQUERADE.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.3.99-pre1/linux/net/ipv4/netfilter/ipt_MASQUERADE.c linux/net/ipv4/netfilter/ipt_MASQUERADE.c
@@ -0,0 +1,171 @@
+/* Masquerade. Simple mapping which alters range to a local IP address
+ (depending on route). */
+#include <linux/types.h>
+#include <linux/ip.h>
+#include <linux/timer.h>
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <net/protocol.h>
+#include <net/checksum.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+EXPORT_NO_SYMBOLS;
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+/* Lock protects masq region inside conntrack */
+static DECLARE_RWLOCK(masq_lock);
+
+/* FIXME: Multiple targets. --RR */
+static int
+masquerade_check(const char *tablename,
+ const struct ipt_entry *e,
+ void *targinfo,
+ unsigned int targinfosize,
+ unsigned int hook_mask)
+{
+ const struct ip_nat_multi_range *mr = targinfo;
+
+ if (targinfosize != IPT_ALIGN(sizeof(*mr))) {
+ DEBUGP("masquerade_check: size %u != %u.\n",
+ targinfosize, sizeof(*mr));
+ return 0;
+ }
+ if (hook_mask & ~(1 << NF_IP_POST_ROUTING)) {
+ DEBUGP("masquerade_check: bad hooks %x.\n", hook_mask);
+ return 0;
+ }
+ if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
+ DEBUGP("masquerade_check: bad MAP_IPS.\n");
+ return 0;
+ }
+ if (mr->rangesize != 1) {
+ DEBUGP("masquerade_check: bad rangesize %u.\n", mr->rangesize);
+ return 0;
+ }
+ return 1;
+}
+
+static unsigned int
+masquerade_target(struct sk_buff **pskb,
+ unsigned int hooknum,
+ const struct net_device *in,
+ const struct net_device *out,
+ const void *targinfo,
+ void *userinfo)
+{
+ struct ip_conntrack *ct;
+ enum ip_conntrack_info ctinfo;
+ const struct ip_nat_range *r;
+ struct ip_nat_multi_range newrange;
+ u_int32_t newsrc;
+ struct rtable *rt;
+
+ IP_NF_ASSERT(hooknum == NF_IP_POST_ROUTING);
+
+ /* FIXME: For the moment, don't do local packets, breaks
+ testsuite for 2.3.49 --RR */
+ if ((*pskb)->sk)
+ return NF_ACCEPT;
+
+ ct = ip_conntrack_get(*pskb, &ctinfo);
+ IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW
+ || ctinfo == IP_CT_RELATED));
+
+ r = targinfo;
+
+ if (ip_route_output(&rt, (*pskb)->nh.iph->daddr,
+ 0,
+ RT_TOS((*pskb)->nh.iph->tos)|RTO_CONN,
+ out->ifindex) != 0) {
+ /* Shouldn't happen */
+ printk("MASQUERADE: No route: Rusty's brain broke!\n");
+ return NF_DROP;
+ }
+
+ newsrc = rt->rt_src;
+ DEBUGP("newsrc = %u.%u.%u.%u\n", IP_PARTS(newsrc));
+ ip_rt_put(rt);
+
+ WRITE_LOCK(&masq_lock);
+ ct->nat.masq_index = out->ifindex;
+ WRITE_UNLOCK(&masq_lock);
+
+ /* Transfer from original range. */
+ newrange = ((struct ip_nat_multi_range)
+ { 1, { { r->flags | IP_NAT_RANGE_MAP_IPS,
+ newsrc, newsrc,
+ r->min, r->max } } });
+
+ /* Hand modified range to generic setup. */
+ return ip_nat_setup_info(ct, &newrange, hooknum);
+}
+
+static inline int
+device_cmp(const struct ip_conntrack *i, void *ifindex)
+{
+ int ret;
+
+ READ_LOCK(&masq_lock);
+ ret = (i->nat.masq_index == (int)(long)ifindex);
+ READ_UNLOCK(&masq_lock);
+
+ return ret;
+}
+
+int masq_device_event(struct notifier_block *this,
+ unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = ptr;
+
+ if (event == NETDEV_DOWN) {
+ /* Device was downed. Search entire table for
+ conntracks which were associated with that device,
+ and forget them. */
+ IP_NF_ASSERT(dev->ifindex != 0);
+
+ ip_ct_selective_cleanup(device_cmp, (void *)(long)dev->ifindex);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block masq_dev_notifier = {
+ masq_device_event,
+ NULL,
+ 0
+};
+
+static struct ipt_target masquerade
+= { { NULL, NULL }, "MASQUERADE", masquerade_target, masquerade_check,
+ THIS_MODULE };
+
+static int __init init(void)
+{
+ int ret;
+
+ ret = ipt_register_target(&masquerade);
+
+ if (ret == 0) {
+ /* Register for device down reports */
+ register_netdevice_notifier(&masq_dev_notifier);
+ }
+
+ return ret;
+}
+
+static void __exit fini(void)
+{
+ ipt_unregister_target(&masquerade);
+ unregister_netdevice_notifier(&masq_dev_notifier);
+}
+
+module_init(init);
+module_exit(fini);
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)