[NETFILTER]: Rename init functions.
[linux-2.6.git] / net / ipv4 / netfilter.c
1 /* IPv4 specific functions of netfilter core */
2 #include <linux/kernel.h>
3 #include <linux/netfilter.h>
4 #include <linux/netfilter_ipv4.h>
5 #include <linux/ip.h>
6 #include <net/route.h>
7 #include <net/xfrm.h>
8 #include <net/ip.h>
9
10 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
11 int ip_route_me_harder(struct sk_buff **pskb)
12 {
13         struct iphdr *iph = (*pskb)->nh.iph;
14         struct rtable *rt;
15         struct flowi fl = {};
16         struct dst_entry *odst;
17         unsigned int hh_len;
18
19         /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
20          * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook.
21          */
22         if (inet_addr_type(iph->saddr) == RTN_LOCAL) {
23                 fl.nl_u.ip4_u.daddr = iph->daddr;
24                 fl.nl_u.ip4_u.saddr = iph->saddr;
25                 fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
26                 fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0;
27 #ifdef CONFIG_IP_ROUTE_FWMARK
28                 fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark;
29 #endif
30                 if (ip_route_output_key(&rt, &fl) != 0)
31                         return -1;
32
33                 /* Drop old route. */
34                 dst_release((*pskb)->dst);
35                 (*pskb)->dst = &rt->u.dst;
36         } else {
37                 /* non-local src, find valid iif to satisfy
38                  * rp-filter when calling ip_route_input. */
39                 fl.nl_u.ip4_u.daddr = iph->saddr;
40                 if (ip_route_output_key(&rt, &fl) != 0)
41                         return -1;
42
43                 odst = (*pskb)->dst;
44                 if (ip_route_input(*pskb, iph->daddr, iph->saddr,
45                                    RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
46                         dst_release(&rt->u.dst);
47                         return -1;
48                 }
49                 dst_release(&rt->u.dst);
50                 dst_release(odst);
51         }
52         
53         if ((*pskb)->dst->error)
54                 return -1;
55
56 #ifdef CONFIG_XFRM
57         if (!(IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED) &&
58             xfrm_decode_session(*pskb, &fl, AF_INET) == 0)
59                 if (xfrm_lookup(&(*pskb)->dst, &fl, (*pskb)->sk, 0))
60                         return -1;
61 #endif
62
63         /* Change in oif may mean change in hh_len. */
64         hh_len = (*pskb)->dst->dev->hard_header_len;
65         if (skb_headroom(*pskb) < hh_len) {
66                 struct sk_buff *nskb;
67
68                 nskb = skb_realloc_headroom(*pskb, hh_len);
69                 if (!nskb) 
70                         return -1;
71                 if ((*pskb)->sk)
72                         skb_set_owner_w(nskb, (*pskb)->sk);
73                 kfree_skb(*pskb);
74                 *pskb = nskb;
75         }
76
77         return 0;
78 }
79 EXPORT_SYMBOL(ip_route_me_harder);
80
81 #ifdef CONFIG_XFRM
82 int ip_xfrm_me_harder(struct sk_buff **pskb)
83 {
84         struct flowi fl;
85         unsigned int hh_len;
86         struct dst_entry *dst;
87
88         if (IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED)
89                 return 0;
90         if (xfrm_decode_session(*pskb, &fl, AF_INET) < 0)
91                 return -1;
92
93         dst = (*pskb)->dst;
94         if (dst->xfrm)
95                 dst = ((struct xfrm_dst *)dst)->route;
96         dst_hold(dst);
97
98         if (xfrm_lookup(&dst, &fl, (*pskb)->sk, 0) < 0)
99                 return -1;
100
101         dst_release((*pskb)->dst);
102         (*pskb)->dst = dst;
103
104         /* Change in oif may mean change in hh_len. */
105         hh_len = (*pskb)->dst->dev->hard_header_len;
106         if (skb_headroom(*pskb) < hh_len) {
107                 struct sk_buff *nskb;
108
109                 nskb = skb_realloc_headroom(*pskb, hh_len);
110                 if (!nskb)
111                         return -1;
112                 if ((*pskb)->sk)
113                         skb_set_owner_w(nskb, (*pskb)->sk);
114                 kfree_skb(*pskb);
115                 *pskb = nskb;
116         }
117         return 0;
118 }
119 EXPORT_SYMBOL(ip_xfrm_me_harder);
120 #endif
121
122 void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
123 EXPORT_SYMBOL(ip_nat_decode_session);
124
125 /*
126  * Extra routing may needed on local out, as the QUEUE target never
127  * returns control to the table.
128  */
129
130 struct ip_rt_info {
131         u_int32_t daddr;
132         u_int32_t saddr;
133         u_int8_t tos;
134 };
135
136 static void queue_save(const struct sk_buff *skb, struct nf_info *info)
137 {
138         struct ip_rt_info *rt_info = nf_info_reroute(info);
139
140         if (info->hook == NF_IP_LOCAL_OUT) {
141                 const struct iphdr *iph = skb->nh.iph;
142
143                 rt_info->tos = iph->tos;
144                 rt_info->daddr = iph->daddr;
145                 rt_info->saddr = iph->saddr;
146         }
147 }
148
149 static int queue_reroute(struct sk_buff **pskb, const struct nf_info *info)
150 {
151         const struct ip_rt_info *rt_info = nf_info_reroute(info);
152
153         if (info->hook == NF_IP_LOCAL_OUT) {
154                 struct iphdr *iph = (*pskb)->nh.iph;
155
156                 if (!(iph->tos == rt_info->tos
157                       && iph->daddr == rt_info->daddr
158                       && iph->saddr == rt_info->saddr))
159                         return ip_route_me_harder(pskb);
160         }
161         return 0;
162 }
163
164 static struct nf_queue_rerouter ip_reroute = {
165         .rer_size       = sizeof(struct ip_rt_info),
166         .save           = queue_save,
167         .reroute        = queue_reroute,
168 };
169
170 static int ipv4_netfilter_init(void)
171 {
172         return nf_register_queue_rerouter(PF_INET, &ip_reroute);
173 }
174
175 static void ipv4_netfilter_fini(void)
176 {
177         nf_unregister_queue_rerouter(PF_INET);
178 }
179
180 module_init(ipv4_netfilter_init);
181 module_exit(ipv4_netfilter_fini);