diff options
Diffstat (limited to 'net/netfilter/xt_REDIRECT.c')
| -rw-r--r-- | net/netfilter/xt_REDIRECT.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/net/netfilter/xt_REDIRECT.c b/net/netfilter/xt_REDIRECT.c new file mode 100644 index 0000000..22a1030 --- /dev/null +++ b/net/netfilter/xt_REDIRECT.c @@ -0,0 +1,190 @@ +/* + * (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> + * Copyright (c) 2011 Patrick McHardy <kaber@trash.net> + * + * 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. + * + * Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6 + * NAT funded by Astaro. + */ + +#include <linux/if.h> +#include <linux/inetdevice.h> +#include <linux/ip.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <linux/netfilter.h> +#include <linux/types.h> +#include <linux/netfilter_ipv4.h> +#include <linux/netfilter_ipv6.h> +#include <linux/netfilter/x_tables.h> +#include <net/addrconf.h> +#include <net/checksum.h> +#include <net/protocol.h> +#include <net/netfilter/nf_nat.h> + +static const struct in6_addr loopback_addr = IN6ADDR_LOOPBACK_INIT; + +static unsigned int +redirect_tg6(struct sk_buff *skb, const struct xt_action_param *par) +{ + const struct nf_nat_range *range = par->targinfo; + struct nf_nat_range newrange; + struct in6_addr newdst; + enum ip_conntrack_info ctinfo; + struct nf_conn *ct; + + ct = nf_ct_get(skb, &ctinfo); + if (par->hooknum == NF_INET_LOCAL_OUT) + newdst = loopback_addr; + else { + struct inet6_dev *idev; + struct inet6_ifaddr *ifa; + bool addr = false; + + rcu_read_lock(); + idev = __in6_dev_get(skb->dev); + if (idev != NULL) { + list_for_each_entry(ifa, &idev->addr_list, if_list) { + newdst = ifa->addr; + addr = true; + break; + } + } + rcu_read_unlock(); + + if (!addr) + return NF_DROP; + } + + newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS; + newrange.min_addr.in6 = newdst; + newrange.max_addr.in6 = newdst; + newrange.min_proto = range->min_proto; + newrange.max_proto = range->max_proto; + + return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST); +} + +static int redirect_tg6_checkentry(const struct xt_tgchk_param *par) +{ + const struct nf_nat_range *range = par->targinfo; + + if (range->flags & NF_NAT_RANGE_MAP_IPS) + return -EINVAL; + return 0; +} + +/* FIXME: Take multiple ranges --RR */ +static int redirect_tg4_check(const struct xt_tgchk_param *par) +{ + const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo; + + if (mr->range[0].flags & NF_NAT_RANGE_MAP_IPS) { + pr_debug("bad MAP_IPS.\n"); + return -EINVAL; + } + if (mr->rangesize != 1) { + pr_debug("bad rangesize %u.\n", mr->rangesize); + return -EINVAL; + } + return 0; +} + +static unsigned int +redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par) +{ + struct nf_conn *ct; + enum ip_conntrack_info ctinfo; + __be32 newdst; + const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo; + struct nf_nat_range newrange; + + NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING || + par->hooknum == NF_INET_LOCAL_OUT); + + ct = nf_ct_get(skb, &ctinfo); + NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED)); + + /* Local packets: make them go to loopback */ + if (par->hooknum == NF_INET_LOCAL_OUT) + newdst = htonl(0x7F000001); + else { + struct in_device *indev; + struct in_ifaddr *ifa; + + newdst = 0; + + rcu_read_lock(); + indev = __in_dev_get_rcu(skb->dev); + if (indev && (ifa = indev->ifa_list)) + newdst = ifa->ifa_local; + rcu_read_unlock(); + + if (!newdst) + return NF_DROP; + } + + /* Transfer from original range. */ + memset(&newrange.min_addr, 0, sizeof(newrange.min_addr)); + memset(&newrange.max_addr, 0, sizeof(newrange.max_addr)); + newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS; + newrange.min_addr.ip = newdst; + newrange.max_addr.ip = newdst; + newrange.min_proto = mr->range[0].min; + newrange.max_proto = mr->range[0].max; + + /* Hand modified range to generic setup. */ + return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST); +} + +static struct xt_target redirect_tg_reg[] __read_mostly = { + { + .name = "REDIRECT", + .family = NFPROTO_IPV6, + .revision = 0, + .table = "nat", + .checkentry = redirect_tg6_checkentry, + .target = redirect_tg6, + .targetsize = sizeof(struct nf_nat_range), + .hooks = (1 << NF_INET_PRE_ROUTING) | + (1 << NF_INET_LOCAL_OUT), + .me = THIS_MODULE, + }, + { + .name = "REDIRECT", + .family = NFPROTO_IPV4, + .revision = 0, + .table = "nat", + .target = redirect_tg4, + .checkentry = redirect_tg4_check, + .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat), + .hooks = (1 << NF_INET_PRE_ROUTING) | + (1 << NF_INET_LOCAL_OUT), + .me = THIS_MODULE, + }, +}; + +static int __init redirect_tg_init(void) +{ + return xt_register_targets(redirect_tg_reg, + ARRAY_SIZE(redirect_tg_reg)); +} + +static void __exit redirect_tg_exit(void) +{ + xt_unregister_targets(redirect_tg_reg, ARRAY_SIZE(redirect_tg_reg)); +} + +module_init(redirect_tg_init); +module_exit(redirect_tg_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); +MODULE_DESCRIPTION("Xtables: Connection redirection to localhost"); +MODULE_ALIAS("ip6t_REDIRECT"); +MODULE_ALIAS("ipt_REDIRECT"); |
