Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
315 lines
8.6 KiB
C
315 lines
8.6 KiB
C
/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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/* Everything about the rules for NAT. */
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#include <linux/types.h>
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#include <linux/ip.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/module.h>
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#include <linux/kmod.h>
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#include <linux/skbuff.h>
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#include <linux/proc_fs.h>
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#include <net/checksum.h>
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#include <net/route.h>
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#include <linux/bitops.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ip_nat.h>
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#include <linux/netfilter_ipv4/ip_nat_core.h>
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#include <linux/netfilter_ipv4/ip_nat_rule.h>
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(format, args...)
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#endif
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#define NAT_VALID_HOOKS ((1<<NF_IP_PRE_ROUTING) | (1<<NF_IP_POST_ROUTING) | (1<<NF_IP_LOCAL_OUT))
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static struct
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{
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struct ipt_replace repl;
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struct ipt_standard entries[3];
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struct ipt_error term;
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} nat_initial_table __initdata
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= { { "nat", NAT_VALID_HOOKS, 4,
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sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
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{ [NF_IP_PRE_ROUTING] = 0,
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[NF_IP_POST_ROUTING] = sizeof(struct ipt_standard),
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[NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 2 },
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{ [NF_IP_PRE_ROUTING] = 0,
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[NF_IP_POST_ROUTING] = sizeof(struct ipt_standard),
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[NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 2 },
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0, NULL, { } },
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{
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/* PRE_ROUTING */
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{ { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
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0,
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sizeof(struct ipt_entry),
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sizeof(struct ipt_standard),
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0, { 0, 0 }, { } },
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{ { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
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-NF_ACCEPT - 1 } },
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/* POST_ROUTING */
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{ { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
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0,
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sizeof(struct ipt_entry),
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sizeof(struct ipt_standard),
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0, { 0, 0 }, { } },
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{ { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
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-NF_ACCEPT - 1 } },
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/* LOCAL_OUT */
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{ { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
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0,
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sizeof(struct ipt_entry),
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sizeof(struct ipt_standard),
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0, { 0, 0 }, { } },
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{ { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
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-NF_ACCEPT - 1 } }
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},
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/* ERROR */
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{ { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
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0,
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sizeof(struct ipt_entry),
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sizeof(struct ipt_error),
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0, { 0, 0 }, { } },
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{ { { { IPT_ALIGN(sizeof(struct ipt_error_target)), IPT_ERROR_TARGET } },
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{ } },
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"ERROR"
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}
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}
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};
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static struct xt_table nat_table = {
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.name = "nat",
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.valid_hooks = NAT_VALID_HOOKS,
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.lock = RW_LOCK_UNLOCKED,
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.me = THIS_MODULE,
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.af = AF_INET,
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};
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/* Source NAT */
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static unsigned int ipt_snat_target(struct sk_buff **pskb,
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const struct net_device *in,
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const struct net_device *out,
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unsigned int hooknum,
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const struct xt_target *target,
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const void *targinfo)
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{
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struct ip_conntrack *ct;
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enum ip_conntrack_info ctinfo;
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const struct ip_nat_multi_range_compat *mr = targinfo;
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IP_NF_ASSERT(hooknum == NF_IP_POST_ROUTING);
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ct = ip_conntrack_get(*pskb, &ctinfo);
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/* Connection must be valid and new. */
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IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED
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|| ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY));
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IP_NF_ASSERT(out);
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return ip_nat_setup_info(ct, &mr->range[0], hooknum);
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}
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/* Before 2.6.11 we did implicit source NAT if required. Warn about change. */
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static void warn_if_extra_mangle(__be32 dstip, __be32 srcip)
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{
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static int warned = 0;
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struct flowi fl = { .nl_u = { .ip4_u = { .daddr = dstip } } };
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struct rtable *rt;
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if (ip_route_output_key(&rt, &fl) != 0)
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return;
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if (rt->rt_src != srcip && !warned) {
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printk("NAT: no longer support implicit source local NAT\n");
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printk("NAT: packet src %u.%u.%u.%u -> dst %u.%u.%u.%u\n",
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NIPQUAD(srcip), NIPQUAD(dstip));
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warned = 1;
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}
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ip_rt_put(rt);
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}
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static unsigned int ipt_dnat_target(struct sk_buff **pskb,
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const struct net_device *in,
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const struct net_device *out,
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unsigned int hooknum,
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const struct xt_target *target,
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const void *targinfo)
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{
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struct ip_conntrack *ct;
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enum ip_conntrack_info ctinfo;
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const struct ip_nat_multi_range_compat *mr = targinfo;
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IP_NF_ASSERT(hooknum == NF_IP_PRE_ROUTING
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|| hooknum == NF_IP_LOCAL_OUT);
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ct = ip_conntrack_get(*pskb, &ctinfo);
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/* Connection must be valid and new. */
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IP_NF_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
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if (hooknum == NF_IP_LOCAL_OUT
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&& mr->range[0].flags & IP_NAT_RANGE_MAP_IPS)
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warn_if_extra_mangle((*pskb)->nh.iph->daddr,
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mr->range[0].min_ip);
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return ip_nat_setup_info(ct, &mr->range[0], hooknum);
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}
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static int ipt_snat_checkentry(const char *tablename,
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const void *entry,
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const struct xt_target *target,
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void *targinfo,
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unsigned int hook_mask)
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{
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struct ip_nat_multi_range_compat *mr = targinfo;
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/* Must be a valid range */
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if (mr->rangesize != 1) {
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printk("SNAT: multiple ranges no longer supported\n");
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return 0;
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}
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return 1;
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}
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static int ipt_dnat_checkentry(const char *tablename,
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const void *entry,
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const struct xt_target *target,
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void *targinfo,
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unsigned int hook_mask)
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{
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struct ip_nat_multi_range_compat *mr = targinfo;
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/* Must be a valid range */
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if (mr->rangesize != 1) {
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printk("DNAT: multiple ranges no longer supported\n");
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return 0;
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}
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if (mr->range[0].flags & IP_NAT_RANGE_PROTO_RANDOM) {
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printk("DNAT: port randomization not supported\n");
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return 0;
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}
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return 1;
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}
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inline unsigned int
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alloc_null_binding(struct ip_conntrack *conntrack,
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struct ip_nat_info *info,
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unsigned int hooknum)
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{
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/* Force range to this IP; let proto decide mapping for
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per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
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Use reply in case it's already been mangled (eg local packet).
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*/
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__be32 ip
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= (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
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? conntrack->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip
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: conntrack->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip);
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struct ip_nat_range range
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= { IP_NAT_RANGE_MAP_IPS, ip, ip, { 0 }, { 0 } };
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DEBUGP("Allocating NULL binding for %p (%u.%u.%u.%u)\n", conntrack,
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NIPQUAD(ip));
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return ip_nat_setup_info(conntrack, &range, hooknum);
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}
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unsigned int
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alloc_null_binding_confirmed(struct ip_conntrack *conntrack,
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struct ip_nat_info *info,
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unsigned int hooknum)
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{
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__be32 ip
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= (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
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? conntrack->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip
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: conntrack->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip);
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u_int16_t all
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= (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
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? conntrack->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.all
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: conntrack->tuplehash[IP_CT_DIR_REPLY].tuple.src.u.all);
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struct ip_nat_range range
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= { IP_NAT_RANGE_MAP_IPS, ip, ip, { all }, { all } };
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DEBUGP("Allocating NULL binding for confirmed %p (%u.%u.%u.%u)\n",
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conntrack, NIPQUAD(ip));
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return ip_nat_setup_info(conntrack, &range, hooknum);
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}
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int ip_nat_rule_find(struct sk_buff **pskb,
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unsigned int hooknum,
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const struct net_device *in,
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const struct net_device *out,
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struct ip_conntrack *ct,
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struct ip_nat_info *info)
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{
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int ret;
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ret = ipt_do_table(pskb, hooknum, in, out, &nat_table);
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if (ret == NF_ACCEPT) {
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if (!ip_nat_initialized(ct, HOOK2MANIP(hooknum)))
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/* NUL mapping */
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ret = alloc_null_binding(ct, info, hooknum);
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}
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return ret;
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}
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static struct xt_target ipt_snat_reg = {
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.name = "SNAT",
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.family = AF_INET,
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.target = ipt_snat_target,
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.targetsize = sizeof(struct ip_nat_multi_range_compat),
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.table = "nat",
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.hooks = 1 << NF_IP_POST_ROUTING,
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.checkentry = ipt_snat_checkentry,
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};
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static struct xt_target ipt_dnat_reg = {
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.name = "DNAT",
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.family = AF_INET,
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.target = ipt_dnat_target,
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.targetsize = sizeof(struct ip_nat_multi_range_compat),
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.table = "nat",
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.hooks = (1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_OUT),
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.checkentry = ipt_dnat_checkentry,
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};
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int __init ip_nat_rule_init(void)
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{
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int ret;
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ret = ipt_register_table(&nat_table, &nat_initial_table.repl);
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if (ret != 0)
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return ret;
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ret = xt_register_target(&ipt_snat_reg);
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if (ret != 0)
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goto unregister_table;
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ret = xt_register_target(&ipt_dnat_reg);
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if (ret != 0)
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goto unregister_snat;
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return ret;
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unregister_snat:
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xt_unregister_target(&ipt_snat_reg);
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unregister_table:
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xt_unregister_table(&nat_table);
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return ret;
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}
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void ip_nat_rule_cleanup(void)
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{
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xt_unregister_target(&ipt_dnat_reg);
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xt_unregister_target(&ipt_snat_reg);
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ipt_unregister_table(&nat_table);
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}
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