Commit | Line | Data |
---|---|---|
2cc7d573 | 1 | /* IPv4 specific functions of netfilter core */ |
020b4c12 HW |
2 | #include <linux/kernel.h> |
3 | #include <linux/netfilter.h> | |
2cc7d573 | 4 | #include <linux/netfilter_ipv4.h> |
3e3850e9 | 5 | #include <linux/ip.h> |
020b4c12 | 6 | #include <net/route.h> |
3e3850e9 PM |
7 | #include <net/xfrm.h> |
8 | #include <net/ip.h> | |
020b4c12 HW |
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 | |
020b4c12 HW |
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 | ||
3e3850e9 PM |
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 | ||
020b4c12 HW |
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); | |
2cc7d573 | 80 | |
ee68cea2 PM |
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 | ||
eb9c7ebe PM |
122 | void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); |
123 | EXPORT_SYMBOL(ip_nat_decode_session); | |
124 | ||
2cc7d573 HW |
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 | ||
bce8032e | 136 | static void nf_ip_saveroute(const struct sk_buff *skb, struct nf_info *info) |
2cc7d573 HW |
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 | ||
bce8032e | 149 | static int nf_ip_reroute(struct sk_buff **pskb, const struct nf_info *info) |
2cc7d573 HW |
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 | ||
422c346f PM |
164 | unsigned int nf_ip_checksum(struct sk_buff *skb, unsigned int hook, |
165 | unsigned int dataoff, u_int8_t protocol) | |
166 | { | |
167 | struct iphdr *iph = skb->nh.iph; | |
168 | unsigned int csum = 0; | |
169 | ||
170 | switch (skb->ip_summed) { | |
171 | case CHECKSUM_HW: | |
172 | if (hook != NF_IP_PRE_ROUTING && hook != NF_IP_LOCAL_IN) | |
173 | break; | |
174 | if ((protocol == 0 && !(u16)csum_fold(skb->csum)) || | |
175 | !csum_tcpudp_magic(iph->saddr, iph->daddr, | |
176 | skb->len - dataoff, protocol, | |
177 | skb->csum)) { | |
178 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
179 | break; | |
180 | } | |
181 | /* fall through */ | |
182 | case CHECKSUM_NONE: | |
183 | if (protocol == 0) | |
184 | skb->csum = 0; | |
185 | else | |
186 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, | |
187 | skb->len - dataoff, | |
188 | protocol, 0); | |
189 | csum = __skb_checksum_complete(skb); | |
190 | } | |
191 | return csum; | |
192 | } | |
193 | ||
194 | EXPORT_SYMBOL(nf_ip_checksum); | |
195 | ||
bce8032e PM |
196 | static struct nf_afinfo nf_ip_afinfo = { |
197 | .family = AF_INET, | |
422c346f | 198 | .checksum = nf_ip_checksum, |
bce8032e PM |
199 | .saveroute = nf_ip_saveroute, |
200 | .reroute = nf_ip_reroute, | |
201 | .route_key_size = sizeof(struct ip_rt_info), | |
2cc7d573 HW |
202 | }; |
203 | ||
65b4b4e8 | 204 | static int ipv4_netfilter_init(void) |
2cc7d573 | 205 | { |
bce8032e | 206 | return nf_register_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
207 | } |
208 | ||
65b4b4e8 | 209 | static void ipv4_netfilter_fini(void) |
2cc7d573 | 210 | { |
bce8032e | 211 | nf_unregister_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
212 | } |
213 | ||
65b4b4e8 AM |
214 | module_init(ipv4_netfilter_init); |
215 | module_exit(ipv4_netfilter_fini); |