[NETFILTER]: Move reroute-after-queue code up to the nf_queue layer.
[linux-2.6.git] / net / ipv4 / netfilter.c
1 /* IPv4 specific functions of netfilter core */
2
3 #include <linux/config.h>
4 #ifdef CONFIG_NETFILTER
5
6 #include <linux/kernel.h>
7 #include <linux/netfilter.h>
8 #include <linux/netfilter_ipv4.h>
9
10 #include <linux/tcp.h>
11 #include <linux/udp.h>
12 #include <linux/icmp.h>
13 #include <net/route.h>
14 #include <linux/ip.h>
15
16 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
17 int ip_route_me_harder(struct sk_buff **pskb)
18 {
19         struct iphdr *iph = (*pskb)->nh.iph;
20         struct rtable *rt;
21         struct flowi fl = {};
22         struct dst_entry *odst;
23         unsigned int hh_len;
24
25         /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
26          * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook.
27          */
28         if (inet_addr_type(iph->saddr) == RTN_LOCAL) {
29                 fl.nl_u.ip4_u.daddr = iph->daddr;
30                 fl.nl_u.ip4_u.saddr = iph->saddr;
31                 fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
32                 fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0;
33 #ifdef CONFIG_IP_ROUTE_FWMARK
34                 fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark;
35 #endif
36                 fl.proto = iph->protocol;
37                 if (ip_route_output_key(&rt, &fl) != 0)
38                         return -1;
39
40                 /* Drop old route. */
41                 dst_release((*pskb)->dst);
42                 (*pskb)->dst = &rt->u.dst;
43         } else {
44                 /* non-local src, find valid iif to satisfy
45                  * rp-filter when calling ip_route_input. */
46                 fl.nl_u.ip4_u.daddr = iph->saddr;
47                 if (ip_route_output_key(&rt, &fl) != 0)
48                         return -1;
49
50                 odst = (*pskb)->dst;
51                 if (ip_route_input(*pskb, iph->daddr, iph->saddr,
52                                    RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
53                         dst_release(&rt->u.dst);
54                         return -1;
55                 }
56                 dst_release(&rt->u.dst);
57                 dst_release(odst);
58         }
59         
60         if ((*pskb)->dst->error)
61                 return -1;
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 /*
82  * Extra routing may needed on local out, as the QUEUE target never
83  * returns control to the table.
84  */
85
86 struct ip_rt_info {
87         u_int32_t daddr;
88         u_int32_t saddr;
89         u_int8_t tos;
90 };
91
92 static void queue_save(const struct sk_buff *skb, struct nf_info *info)
93 {
94         struct ip_rt_info *rt_info = nf_info_reroute(info);
95
96         if (info->hook == NF_IP_LOCAL_OUT) {
97                 const struct iphdr *iph = skb->nh.iph;
98
99                 rt_info->tos = iph->tos;
100                 rt_info->daddr = iph->daddr;
101                 rt_info->saddr = iph->saddr;
102         }
103 }
104
105 static int queue_reroute(struct sk_buff **pskb, const struct nf_info *info)
106 {
107         const struct ip_rt_info *rt_info = nf_info_reroute(info);
108
109         if (info->hook == NF_IP_LOCAL_OUT) {
110                 struct iphdr *iph = (*pskb)->nh.iph;
111
112                 if (!(iph->tos == rt_info->tos
113                       && iph->daddr == rt_info->daddr
114                       && iph->saddr == rt_info->saddr))
115                         return ip_route_me_harder(pskb);
116         }
117         return 0;
118 }
119
120 static struct nf_queue_rerouter ip_reroute = {
121         .rer_size       = sizeof(struct ip_rt_info),
122         .save           = queue_save,
123         .reroute        = queue_reroute,
124 };
125
126 static int init(void)
127 {
128         return nf_register_queue_rerouter(PF_INET, &ip_reroute);
129 }
130
131 static void fini(void)
132 {
133         nf_unregister_queue_rerouter(PF_INET);
134 }
135
136 module_init(init);
137 module_exit(fini);
138
139 #endif /* CONFIG_NETFILTER */