| 1 |
1275 |
phoenix |
/* This file contains all the functions required for the standalone
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| 2 |
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ip_nat module.
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| 3 |
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| 4 |
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These are not required by the compatibility layer.
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*/
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/* (c) 1999 Paul `Rusty' Russell. Licenced under the GNU General
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* Public Licence.
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*
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* 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
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* - new API and handling of conntrack/nat helpers
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* - now capable of multiple expectations for one master
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* */
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#include <linux/config.h>
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#include <linux/types.h>
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#include <linux/ip.h>
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| 18 |
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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/skbuff.h>
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#include <linux/proc_fs.h>
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#include <net/checksum.h>
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#include <linux/spinlock.h>
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| 25 |
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#include <linux/version.h>
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| 26 |
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#include <linux/brlock.h>
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| 28 |
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#define ASSERT_READ_LOCK(x) MUST_BE_READ_LOCKED(&ip_nat_lock)
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#define ASSERT_WRITE_LOCK(x) MUST_BE_WRITE_LOCKED(&ip_nat_lock)
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#include <linux/netfilter_ipv4/ip_nat.h>
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#include <linux/netfilter_ipv4/ip_nat_rule.h>
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| 33 |
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#include <linux/netfilter_ipv4/ip_nat_protocol.h>
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#include <linux/netfilter_ipv4/ip_nat_core.h>
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#include <linux/netfilter_ipv4/ip_nat_helper.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ip_conntrack_core.h>
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#include <linux/netfilter_ipv4/listhelp.h>
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| 40 |
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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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| 46 |
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#define HOOKNAME(hooknum) ((hooknum) == NF_IP_POST_ROUTING ? "POST_ROUTING" \
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: ((hooknum) == NF_IP_PRE_ROUTING ? "PRE_ROUTING" \
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: ((hooknum) == NF_IP_LOCAL_OUT ? "LOCAL_OUT" \
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| 49 |
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: ((hooknum) == NF_IP_LOCAL_IN ? "LOCAL_IN" \
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| 50 |
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: "*ERROR*")))
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| 52 |
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static inline int call_expect(struct ip_conntrack *master,
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| 53 |
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struct sk_buff **pskb,
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| 54 |
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unsigned int hooknum,
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| 55 |
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struct ip_conntrack *ct,
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| 56 |
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struct ip_nat_info *info)
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{
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| 58 |
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return master->nat.info.helper->expect(pskb, hooknum, ct, info);
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| 59 |
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}
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| 60 |
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| 61 |
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static unsigned int
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ip_nat_fn(unsigned int hooknum,
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| 63 |
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struct sk_buff **pskb,
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| 64 |
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const struct net_device *in,
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| 65 |
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const struct net_device *out,
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| 66 |
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int (*okfn)(struct sk_buff *))
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| 67 |
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{
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| 68 |
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struct ip_conntrack *ct;
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| 69 |
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enum ip_conntrack_info ctinfo;
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struct ip_nat_info *info;
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/* maniptype == SRC for postrouting. */
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enum ip_nat_manip_type maniptype = HOOK2MANIP(hooknum);
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| 74 |
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/* We never see fragments: conntrack defrags on pre-routing
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and local-out, and ip_nat_out protects post-routing. */
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IP_NF_ASSERT(!((*pskb)->nh.iph->frag_off
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| 77 |
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& htons(IP_MF|IP_OFFSET)));
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| 79 |
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(*pskb)->nfcache |= NFC_UNKNOWN;
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| 80 |
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| 81 |
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/* If we had a hardware checksum before, it's now invalid */
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| 82 |
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if ((*pskb)->ip_summed == CHECKSUM_HW)
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| 83 |
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(*pskb)->ip_summed = CHECKSUM_NONE;
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| 84 |
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| 85 |
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ct = ip_conntrack_get(*pskb, &ctinfo);
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| 86 |
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/* Can't track? It's not due to stress, or conntrack would
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| 87 |
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have dropped it. Hence it's the user's responsibilty to
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packet filter it out, or implement conntrack/NAT for that
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| 89 |
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protocol. 8) --RR */
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| 90 |
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if (!ct) {
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| 91 |
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/* Exception: ICMP redirect to new connection (not in
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| 92 |
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hash table yet). We must not let this through, in
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| 93 |
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case we're doing NAT to the same network. */
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| 94 |
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struct iphdr *iph = (*pskb)->nh.iph;
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| 95 |
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struct icmphdr *hdr = (struct icmphdr *)
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| 96 |
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((u_int32_t *)iph + iph->ihl);
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| 97 |
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if (iph->protocol == IPPROTO_ICMP
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| 98 |
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&& hdr->type == ICMP_REDIRECT)
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| 99 |
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return NF_DROP;
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| 100 |
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return NF_ACCEPT;
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| 101 |
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}
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| 102 |
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| 103 |
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switch (ctinfo) {
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| 104 |
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case IP_CT_RELATED:
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| 105 |
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case IP_CT_RELATED+IP_CT_IS_REPLY:
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| 106 |
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if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP) {
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| 107 |
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return icmp_reply_translation(*pskb, ct, hooknum,
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| 108 |
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CTINFO2DIR(ctinfo));
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| 109 |
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}
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| 110 |
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/* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
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| 111 |
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case IP_CT_NEW:
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| 112 |
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info = &ct->nat.info;
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| 113 |
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| 114 |
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WRITE_LOCK(&ip_nat_lock);
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| 115 |
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/* Seen it before? This can happen for loopback, retrans,
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| 116 |
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or local packets.. */
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| 117 |
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if (!(info->initialized & (1 << maniptype))
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| 118 |
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#ifndef CONFIG_IP_NF_NAT_LOCAL
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| 119 |
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/* If this session has already been confirmed we must not
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| 120 |
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* touch it again even if there is no mapping set up.
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| 121 |
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* Can only happen on local->local traffic with
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| 122 |
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* CONFIG_IP_NF_NAT_LOCAL disabled.
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| 123 |
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*/
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| 124 |
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&& !(ct->status & IPS_CONFIRMED)
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| 125 |
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#endif
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| 126 |
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) {
|
| 127 |
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unsigned int ret;
|
| 128 |
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|
| 129 |
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if (ct->master
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| 130 |
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&& master_ct(ct)->nat.info.helper
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| 131 |
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&& master_ct(ct)->nat.info.helper->expect) {
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| 132 |
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ret = call_expect(master_ct(ct), pskb,
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| 133 |
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hooknum, ct, info);
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| 134 |
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} else {
|
| 135 |
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#ifdef CONFIG_IP_NF_NAT_LOCAL
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| 136 |
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/* LOCAL_IN hook doesn't have a chain! */
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| 137 |
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if (hooknum == NF_IP_LOCAL_IN)
|
| 138 |
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ret = alloc_null_binding(ct, info,
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| 139 |
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hooknum);
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| 140 |
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else
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| 141 |
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#endif
|
| 142 |
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ret = ip_nat_rule_find(pskb, hooknum, in, out,
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| 143 |
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ct, info);
|
| 144 |
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}
|
| 145 |
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| 146 |
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if (ret != NF_ACCEPT) {
|
| 147 |
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WRITE_UNLOCK(&ip_nat_lock);
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| 148 |
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return ret;
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| 149 |
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}
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| 150 |
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} else
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| 151 |
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DEBUGP("Already setup manip %s for ct %p\n",
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| 152 |
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maniptype == IP_NAT_MANIP_SRC ? "SRC" : "DST",
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| 153 |
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ct);
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| 154 |
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WRITE_UNLOCK(&ip_nat_lock);
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| 155 |
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break;
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| 156 |
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| 157 |
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default:
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| 158 |
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/* ESTABLISHED */
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| 159 |
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IP_NF_ASSERT(ctinfo == IP_CT_ESTABLISHED
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| 160 |
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|| ctinfo == (IP_CT_ESTABLISHED+IP_CT_IS_REPLY));
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| 161 |
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info = &ct->nat.info;
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| 162 |
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}
|
| 163 |
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| 164 |
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IP_NF_ASSERT(info);
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| 165 |
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return do_bindings(ct, ctinfo, info, hooknum, pskb);
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| 166 |
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}
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| 167 |
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| 168 |
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static unsigned int
|
| 169 |
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ip_nat_out(unsigned int hooknum,
|
| 170 |
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struct sk_buff **pskb,
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| 171 |
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const struct net_device *in,
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| 172 |
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const struct net_device *out,
|
| 173 |
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int (*okfn)(struct sk_buff *))
|
| 174 |
|
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{
|
| 175 |
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/* root is playing with raw sockets. */
|
| 176 |
|
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if ((*pskb)->len < sizeof(struct iphdr)
|
| 177 |
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|| (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr))
|
| 178 |
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return NF_ACCEPT;
|
| 179 |
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|
| 180 |
|
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/* We can hit fragment here; forwarded packets get
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| 181 |
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defragmented by connection tracking coming in, then
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| 182 |
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fragmented (grr) by the forward code.
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| 183 |
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|
| 184 |
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In future: If we have nfct != NULL, AND we have NAT
|
| 185 |
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initialized, AND there is no helper, then we can do full
|
| 186 |
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NAPT on the head, and IP-address-only NAT on the rest.
|
| 187 |
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|
| 188 |
|
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I'm starting to have nightmares about fragments. */
|
| 189 |
|
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|
| 190 |
|
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if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
|
| 191 |
|
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*pskb = ip_ct_gather_frags(*pskb);
|
| 192 |
|
|
|
| 193 |
|
|
if (!*pskb)
|
| 194 |
|
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return NF_STOLEN;
|
| 195 |
|
|
}
|
| 196 |
|
|
|
| 197 |
|
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return ip_nat_fn(hooknum, pskb, in, out, okfn);
|
| 198 |
|
|
}
|
| 199 |
|
|
|
| 200 |
|
|
#ifdef CONFIG_IP_NF_NAT_LOCAL
|
| 201 |
|
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static unsigned int
|
| 202 |
|
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ip_nat_local_fn(unsigned int hooknum,
|
| 203 |
|
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struct sk_buff **pskb,
|
| 204 |
|
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const struct net_device *in,
|
| 205 |
|
|
const struct net_device *out,
|
| 206 |
|
|
int (*okfn)(struct sk_buff *))
|
| 207 |
|
|
{
|
| 208 |
|
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u_int32_t saddr, daddr;
|
| 209 |
|
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unsigned int ret;
|
| 210 |
|
|
|
| 211 |
|
|
/* root is playing with raw sockets. */
|
| 212 |
|
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if ((*pskb)->len < sizeof(struct iphdr)
|
| 213 |
|
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|| (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr))
|
| 214 |
|
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return NF_ACCEPT;
|
| 215 |
|
|
|
| 216 |
|
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saddr = (*pskb)->nh.iph->saddr;
|
| 217 |
|
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daddr = (*pskb)->nh.iph->daddr;
|
| 218 |
|
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|
| 219 |
|
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ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
|
| 220 |
|
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if (ret != NF_DROP && ret != NF_STOLEN
|
| 221 |
|
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&& ((*pskb)->nh.iph->saddr != saddr
|
| 222 |
|
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|| (*pskb)->nh.iph->daddr != daddr))
|
| 223 |
|
|
return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
|
| 224 |
|
|
return ret;
|
| 225 |
|
|
}
|
| 226 |
|
|
#endif
|
| 227 |
|
|
|
| 228 |
|
|
/* We must be after connection tracking and before packet filtering. */
|
| 229 |
|
|
|
| 230 |
|
|
/* Before packet filtering, change destination */
|
| 231 |
|
|
static struct nf_hook_ops ip_nat_in_ops
|
| 232 |
|
|
= { { NULL, NULL }, ip_nat_fn, PF_INET, NF_IP_PRE_ROUTING, NF_IP_PRI_NAT_DST };
|
| 233 |
|
|
/* After packet filtering, change source */
|
| 234 |
|
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static struct nf_hook_ops ip_nat_out_ops
|
| 235 |
|
|
= { { NULL, NULL }, ip_nat_out, PF_INET, NF_IP_POST_ROUTING, NF_IP_PRI_NAT_SRC};
|
| 236 |
|
|
|
| 237 |
|
|
#ifdef CONFIG_IP_NF_NAT_LOCAL
|
| 238 |
|
|
/* Before packet filtering, change destination */
|
| 239 |
|
|
static struct nf_hook_ops ip_nat_local_out_ops
|
| 240 |
|
|
= { { NULL, NULL }, ip_nat_local_fn, PF_INET, NF_IP_LOCAL_OUT, NF_IP_PRI_NAT_DST };
|
| 241 |
|
|
/* After packet filtering, change source for reply packets of LOCAL_OUT DNAT */
|
| 242 |
|
|
static struct nf_hook_ops ip_nat_local_in_ops
|
| 243 |
|
|
= { { NULL, NULL }, ip_nat_fn, PF_INET, NF_IP_LOCAL_IN, NF_IP_PRI_NAT_SRC };
|
| 244 |
|
|
#endif
|
| 245 |
|
|
|
| 246 |
|
|
/* Protocol registration. */
|
| 247 |
|
|
int ip_nat_protocol_register(struct ip_nat_protocol *proto)
|
| 248 |
|
|
{
|
| 249 |
|
|
int ret = 0;
|
| 250 |
|
|
struct list_head *i;
|
| 251 |
|
|
|
| 252 |
|
|
WRITE_LOCK(&ip_nat_lock);
|
| 253 |
|
|
for (i = protos.next; i != &protos; i = i->next) {
|
| 254 |
|
|
if (((struct ip_nat_protocol *)i)->protonum
|
| 255 |
|
|
== proto->protonum) {
|
| 256 |
|
|
ret = -EBUSY;
|
| 257 |
|
|
goto out;
|
| 258 |
|
|
}
|
| 259 |
|
|
}
|
| 260 |
|
|
|
| 261 |
|
|
list_prepend(&protos, proto);
|
| 262 |
|
|
MOD_INC_USE_COUNT;
|
| 263 |
|
|
|
| 264 |
|
|
out:
|
| 265 |
|
|
WRITE_UNLOCK(&ip_nat_lock);
|
| 266 |
|
|
return ret;
|
| 267 |
|
|
}
|
| 268 |
|
|
|
| 269 |
|
|
/* Noone stores the protocol anywhere; simply delete it. */
|
| 270 |
|
|
void ip_nat_protocol_unregister(struct ip_nat_protocol *proto)
|
| 271 |
|
|
{
|
| 272 |
|
|
WRITE_LOCK(&ip_nat_lock);
|
| 273 |
|
|
LIST_DELETE(&protos, proto);
|
| 274 |
|
|
WRITE_UNLOCK(&ip_nat_lock);
|
| 275 |
|
|
|
| 276 |
|
|
/* Someone could be still looking at the proto in a bh. */
|
| 277 |
|
|
br_write_lock_bh(BR_NETPROTO_LOCK);
|
| 278 |
|
|
br_write_unlock_bh(BR_NETPROTO_LOCK);
|
| 279 |
|
|
|
| 280 |
|
|
MOD_DEC_USE_COUNT;
|
| 281 |
|
|
}
|
| 282 |
|
|
|
| 283 |
|
|
static int init_or_cleanup(int init)
|
| 284 |
|
|
{
|
| 285 |
|
|
int ret = 0;
|
| 286 |
|
|
|
| 287 |
|
|
if (!init) goto cleanup;
|
| 288 |
|
|
|
| 289 |
|
|
ret = ip_nat_rule_init();
|
| 290 |
|
|
if (ret < 0) {
|
| 291 |
|
|
printk("ip_nat_init: can't setup rules.\n");
|
| 292 |
|
|
goto cleanup_nothing;
|
| 293 |
|
|
}
|
| 294 |
|
|
ret = ip_nat_init();
|
| 295 |
|
|
if (ret < 0) {
|
| 296 |
|
|
printk("ip_nat_init: can't setup rules.\n");
|
| 297 |
|
|
goto cleanup_rule_init;
|
| 298 |
|
|
}
|
| 299 |
|
|
ret = nf_register_hook(&ip_nat_in_ops);
|
| 300 |
|
|
if (ret < 0) {
|
| 301 |
|
|
printk("ip_nat_init: can't register in hook.\n");
|
| 302 |
|
|
goto cleanup_nat;
|
| 303 |
|
|
}
|
| 304 |
|
|
ret = nf_register_hook(&ip_nat_out_ops);
|
| 305 |
|
|
if (ret < 0) {
|
| 306 |
|
|
printk("ip_nat_init: can't register out hook.\n");
|
| 307 |
|
|
goto cleanup_inops;
|
| 308 |
|
|
}
|
| 309 |
|
|
#ifdef CONFIG_IP_NF_NAT_LOCAL
|
| 310 |
|
|
ret = nf_register_hook(&ip_nat_local_out_ops);
|
| 311 |
|
|
if (ret < 0) {
|
| 312 |
|
|
printk("ip_nat_init: can't register local out hook.\n");
|
| 313 |
|
|
goto cleanup_outops;
|
| 314 |
|
|
}
|
| 315 |
|
|
ret = nf_register_hook(&ip_nat_local_in_ops);
|
| 316 |
|
|
if (ret < 0) {
|
| 317 |
|
|
printk("ip_nat_init: can't register local in hook.\n");
|
| 318 |
|
|
goto cleanup_localoutops;
|
| 319 |
|
|
}
|
| 320 |
|
|
#endif
|
| 321 |
|
|
return ret;
|
| 322 |
|
|
|
| 323 |
|
|
cleanup:
|
| 324 |
|
|
#ifdef CONFIG_IP_NF_NAT_LOCAL
|
| 325 |
|
|
nf_unregister_hook(&ip_nat_local_in_ops);
|
| 326 |
|
|
cleanup_localoutops:
|
| 327 |
|
|
nf_unregister_hook(&ip_nat_local_out_ops);
|
| 328 |
|
|
cleanup_outops:
|
| 329 |
|
|
#endif
|
| 330 |
|
|
nf_unregister_hook(&ip_nat_out_ops);
|
| 331 |
|
|
cleanup_inops:
|
| 332 |
|
|
nf_unregister_hook(&ip_nat_in_ops);
|
| 333 |
|
|
cleanup_nat:
|
| 334 |
|
|
ip_nat_cleanup();
|
| 335 |
|
|
cleanup_rule_init:
|
| 336 |
|
|
ip_nat_rule_cleanup();
|
| 337 |
|
|
cleanup_nothing:
|
| 338 |
|
|
MUST_BE_READ_WRITE_UNLOCKED(&ip_nat_lock);
|
| 339 |
|
|
return ret;
|
| 340 |
|
|
}
|
| 341 |
|
|
|
| 342 |
|
|
static int __init init(void)
|
| 343 |
|
|
{
|
| 344 |
|
|
return init_or_cleanup(1);
|
| 345 |
|
|
}
|
| 346 |
|
|
|
| 347 |
|
|
static void __exit fini(void)
|
| 348 |
|
|
{
|
| 349 |
|
|
init_or_cleanup(0);
|
| 350 |
|
|
}
|
| 351 |
|
|
|
| 352 |
|
|
module_init(init);
|
| 353 |
|
|
module_exit(fini);
|
| 354 |
|
|
|
| 355 |
|
|
EXPORT_SYMBOL(ip_nat_setup_info);
|
| 356 |
|
|
EXPORT_SYMBOL(ip_nat_protocol_register);
|
| 357 |
|
|
EXPORT_SYMBOL(ip_nat_protocol_unregister);
|
| 358 |
|
|
EXPORT_SYMBOL(ip_nat_helper_register);
|
| 359 |
|
|
EXPORT_SYMBOL(ip_nat_helper_unregister);
|
| 360 |
|
|
EXPORT_SYMBOL(ip_nat_cheat_check);
|
| 361 |
|
|
EXPORT_SYMBOL(ip_nat_mangle_tcp_packet);
|
| 362 |
|
|
EXPORT_SYMBOL(ip_nat_mangle_udp_packet);
|
| 363 |
|
|
EXPORT_SYMBOL(ip_nat_used_tuple);
|
| 364 |
|
|
MODULE_LICENSE("GPL");
|
