-/* Same. Just like SNAT, only try to make the connections
- * between client A and server B always have the same source ip.
- *
- * (C) 2000 Paul `Rusty' Russell
- * (C) 2001 Martin Josefsson
- *
- * 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/types.h>
-#include <linux/ip.h>
-#include <linux/timer.h>
-#include <linux/module.h>
-#include <linux/netfilter.h>
-#include <linux/netdevice.h>
-#include <linux/if.h>
-#include <linux/inetdevice.h>
-#include <net/protocol.h>
-#include <net/checksum.h>
-#include <linux/netfilter_ipv4.h>
-#include <linux/netfilter/x_tables.h>
-#include <net/netfilter/nf_nat_rule.h>
-#include <linux/netfilter_ipv4/ipt_SAME.h>
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Martin Josefsson <gandalf@wlug.westbo.se>");
-MODULE_DESCRIPTION("iptables special SNAT module for consistent sourceip");
-
-static bool
-same_tg_check(const char *tablename, const void *e,
- const struct xt_target *target, void *targinfo,
- unsigned int hook_mask)
-{
- unsigned int count, countess, rangeip, index = 0;
- struct ipt_same_info *mr = targinfo;
-
- mr->ipnum = 0;
-
- if (mr->rangesize < 1) {
- pr_debug("same_check: need at least one dest range.\n");
- return false;
- }
- if (mr->rangesize > IPT_SAME_MAX_RANGE) {
- pr_debug("same_check: too many ranges specified, maximum "
- "is %u ranges\n", IPT_SAME_MAX_RANGE);
- return false;
- }
- for (count = 0; count < mr->rangesize; count++) {
- if (ntohl(mr->range[count].min_ip) >
- ntohl(mr->range[count].max_ip)) {
- pr_debug("same_check: min_ip is larger than max_ip in "
- "range `%u.%u.%u.%u-%u.%u.%u.%u'.\n",
- NIPQUAD(mr->range[count].min_ip),
- NIPQUAD(mr->range[count].max_ip));
- return false;
- }
- if (!(mr->range[count].flags & IP_NAT_RANGE_MAP_IPS)) {
- pr_debug("same_check: bad MAP_IPS.\n");
- return false;
- }
- rangeip = (ntohl(mr->range[count].max_ip) -
- ntohl(mr->range[count].min_ip) + 1);
- mr->ipnum += rangeip;
-
- pr_debug("same_check: range %u, ipnum = %u\n", count, rangeip);
- }
- pr_debug("same_check: total ipaddresses = %u\n", mr->ipnum);
-
- mr->iparray = kmalloc((sizeof(u_int32_t) * mr->ipnum), GFP_KERNEL);
- if (!mr->iparray) {
- pr_debug("same_check: Couldn't allocate %Zu bytes "
- "for %u ipaddresses!\n",
- (sizeof(u_int32_t) * mr->ipnum), mr->ipnum);
- return false;
- }
- pr_debug("same_check: Allocated %Zu bytes for %u ipaddresses.\n",
- (sizeof(u_int32_t) * mr->ipnum), mr->ipnum);
-
- for (count = 0; count < mr->rangesize; count++) {
- for (countess = ntohl(mr->range[count].min_ip);
- countess <= ntohl(mr->range[count].max_ip);
- countess++) {
- mr->iparray[index] = countess;
- pr_debug("same_check: Added ipaddress `%u.%u.%u.%u' "
- "in index %u.\n", HIPQUAD(countess), index);
- index++;
- }
- }
- return true;
-}
-
-static void same_tg_destroy(const struct xt_target *target, void *targinfo)
-{
- struct ipt_same_info *mr = targinfo;
-
- kfree(mr->iparray);
-
- pr_debug("same_destroy: Deallocated %Zu bytes for %u ipaddresses.\n",
- (sizeof(u_int32_t) * mr->ipnum), mr->ipnum);
-}
-
-static unsigned int
-same_tg(struct sk_buff *skb, const struct net_device *in,
- const struct net_device *out, unsigned int hooknum,
- const struct xt_target *target, const void *targinfo)
-{
- struct nf_conn *ct;
- enum ip_conntrack_info ctinfo;
- u_int32_t tmpip, aindex;
- __be32 new_ip;
- const struct ipt_same_info *same = targinfo;
- struct nf_nat_range newrange;
- const struct nf_conntrack_tuple *t;
-
- NF_CT_ASSERT(hooknum == NF_INET_PRE_ROUTING ||
- hooknum == NF_INET_POST_ROUTING);
- ct = nf_ct_get(skb, &ctinfo);
-
- t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
-
- /* Base new source on real src ip and optionally dst ip,
- giving some hope for consistency across reboots.
- Here we calculate the index in same->iparray which
- holds the ipaddress we should use */
-
- tmpip = ntohl(t->src.u3.ip);
-
- if (!(same->info & IPT_SAME_NODST))
- tmpip += ntohl(t->dst.u3.ip);
- aindex = tmpip % same->ipnum;
-
- new_ip = htonl(same->iparray[aindex]);
-
- pr_debug("ipt_SAME: src=%u.%u.%u.%u dst=%u.%u.%u.%u, "
- "new src=%u.%u.%u.%u\n",
- NIPQUAD(t->src.u3.ip), NIPQUAD(t->dst.u3.ip), NIPQUAD(new_ip));
-
- /* Transfer from original range. */
- newrange = ((struct nf_nat_range)
- { same->range[0].flags, new_ip, new_ip,
- /* FIXME: Use ports from correct range! */
- same->range[0].min, same->range[0].max });
-
- /* Hand modified range to generic setup. */
- return nf_nat_setup_info(ct, &newrange, hooknum);
-}
-
-static struct xt_target same_tg_reg __read_mostly = {
- .name = "SAME",
- .family = AF_INET,
- .target = same_tg,
- .targetsize = sizeof(struct ipt_same_info),
- .table = "nat",
- .hooks = (1 << NF_INET_PRE_ROUTING) |
- (1 << NF_INET_POST_ROUTING),
- .checkentry = same_tg_check,
- .destroy = same_tg_destroy,
- .me = THIS_MODULE,
-};
-
-static int __init same_tg_init(void)
-{
- return xt_register_target(&same_tg_reg);
-}
-
-static void __exit same_tg_exit(void)
-{
- xt_unregister_target(&same_tg_reg);
-}
-
-module_init(same_tg_init);
-module_exit(same_tg_exit);
-
git.openpandora.org / pandora-kernel.git / commitdiff