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 */ | |
b4c4ed17 | 11 | int ip_route_me_harder(struct sk_buff **pskb, unsigned addr_type) |
020b4c12 HW |
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 | ||
b4c4ed17 SH |
19 | if (addr_type == RTN_UNSPEC) |
20 | addr_type = inet_addr_type(iph->saddr); | |
21 | ||
020b4c12 HW |
22 | /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause |
23 | * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook. | |
24 | */ | |
b4c4ed17 | 25 | if (addr_type == RTN_LOCAL) { |
020b4c12 HW |
26 | fl.nl_u.ip4_u.daddr = iph->daddr; |
27 | fl.nl_u.ip4_u.saddr = iph->saddr; | |
28 | fl.nl_u.ip4_u.tos = RT_TOS(iph->tos); | |
29 | fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0; | |
30 | #ifdef CONFIG_IP_ROUTE_FWMARK | |
82e91ffe | 31 | fl.nl_u.ip4_u.fwmark = (*pskb)->mark; |
020b4c12 | 32 | #endif |
020b4c12 HW |
33 | if (ip_route_output_key(&rt, &fl) != 0) |
34 | return -1; | |
35 | ||
36 | /* Drop old route. */ | |
37 | dst_release((*pskb)->dst); | |
38 | (*pskb)->dst = &rt->u.dst; | |
39 | } else { | |
40 | /* non-local src, find valid iif to satisfy | |
41 | * rp-filter when calling ip_route_input. */ | |
42 | fl.nl_u.ip4_u.daddr = iph->saddr; | |
43 | if (ip_route_output_key(&rt, &fl) != 0) | |
44 | return -1; | |
45 | ||
46 | odst = (*pskb)->dst; | |
47 | if (ip_route_input(*pskb, iph->daddr, iph->saddr, | |
48 | RT_TOS(iph->tos), rt->u.dst.dev) != 0) { | |
49 | dst_release(&rt->u.dst); | |
50 | return -1; | |
51 | } | |
52 | dst_release(&rt->u.dst); | |
53 | dst_release(odst); | |
54 | } | |
55 | ||
56 | if ((*pskb)->dst->error) | |
57 | return -1; | |
58 | ||
3e3850e9 PM |
59 | #ifdef CONFIG_XFRM |
60 | if (!(IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED) && | |
61 | xfrm_decode_session(*pskb, &fl, AF_INET) == 0) | |
62 | if (xfrm_lookup(&(*pskb)->dst, &fl, (*pskb)->sk, 0)) | |
63 | return -1; | |
64 | #endif | |
65 | ||
020b4c12 HW |
66 | /* Change in oif may mean change in hh_len. */ |
67 | hh_len = (*pskb)->dst->dev->hard_header_len; | |
68 | if (skb_headroom(*pskb) < hh_len) { | |
69 | struct sk_buff *nskb; | |
70 | ||
71 | nskb = skb_realloc_headroom(*pskb, hh_len); | |
72 | if (!nskb) | |
73 | return -1; | |
74 | if ((*pskb)->sk) | |
75 | skb_set_owner_w(nskb, (*pskb)->sk); | |
76 | kfree_skb(*pskb); | |
77 | *pskb = nskb; | |
78 | } | |
79 | ||
80 | return 0; | |
81 | } | |
82 | EXPORT_SYMBOL(ip_route_me_harder); | |
2cc7d573 | 83 | |
ee68cea2 PM |
84 | #ifdef CONFIG_XFRM |
85 | int ip_xfrm_me_harder(struct sk_buff **pskb) | |
86 | { | |
87 | struct flowi fl; | |
88 | unsigned int hh_len; | |
89 | struct dst_entry *dst; | |
90 | ||
91 | if (IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED) | |
92 | return 0; | |
93 | if (xfrm_decode_session(*pskb, &fl, AF_INET) < 0) | |
94 | return -1; | |
95 | ||
96 | dst = (*pskb)->dst; | |
97 | if (dst->xfrm) | |
98 | dst = ((struct xfrm_dst *)dst)->route; | |
99 | dst_hold(dst); | |
100 | ||
101 | if (xfrm_lookup(&dst, &fl, (*pskb)->sk, 0) < 0) | |
102 | return -1; | |
103 | ||
104 | dst_release((*pskb)->dst); | |
105 | (*pskb)->dst = dst; | |
106 | ||
107 | /* Change in oif may mean change in hh_len. */ | |
108 | hh_len = (*pskb)->dst->dev->hard_header_len; | |
109 | if (skb_headroom(*pskb) < hh_len) { | |
110 | struct sk_buff *nskb; | |
111 | ||
112 | nskb = skb_realloc_headroom(*pskb, hh_len); | |
113 | if (!nskb) | |
114 | return -1; | |
115 | if ((*pskb)->sk) | |
116 | skb_set_owner_w(nskb, (*pskb)->sk); | |
117 | kfree_skb(*pskb); | |
118 | *pskb = nskb; | |
119 | } | |
120 | return 0; | |
121 | } | |
122 | EXPORT_SYMBOL(ip_xfrm_me_harder); | |
123 | #endif | |
124 | ||
eb9c7ebe PM |
125 | void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); |
126 | EXPORT_SYMBOL(ip_nat_decode_session); | |
127 | ||
2cc7d573 HW |
128 | /* |
129 | * Extra routing may needed on local out, as the QUEUE target never | |
130 | * returns control to the table. | |
131 | */ | |
132 | ||
133 | struct ip_rt_info { | |
59b8bfd8 AV |
134 | __be32 daddr; |
135 | __be32 saddr; | |
2cc7d573 HW |
136 | u_int8_t tos; |
137 | }; | |
138 | ||
bce8032e | 139 | static void nf_ip_saveroute(const struct sk_buff *skb, struct nf_info *info) |
2cc7d573 HW |
140 | { |
141 | struct ip_rt_info *rt_info = nf_info_reroute(info); | |
142 | ||
143 | if (info->hook == NF_IP_LOCAL_OUT) { | |
144 | const struct iphdr *iph = skb->nh.iph; | |
145 | ||
146 | rt_info->tos = iph->tos; | |
147 | rt_info->daddr = iph->daddr; | |
148 | rt_info->saddr = iph->saddr; | |
149 | } | |
150 | } | |
151 | ||
bce8032e | 152 | static int nf_ip_reroute(struct sk_buff **pskb, const struct nf_info *info) |
2cc7d573 HW |
153 | { |
154 | const struct ip_rt_info *rt_info = nf_info_reroute(info); | |
155 | ||
156 | if (info->hook == NF_IP_LOCAL_OUT) { | |
157 | struct iphdr *iph = (*pskb)->nh.iph; | |
158 | ||
159 | if (!(iph->tos == rt_info->tos | |
160 | && iph->daddr == rt_info->daddr | |
161 | && iph->saddr == rt_info->saddr)) | |
b4c4ed17 | 162 | return ip_route_me_harder(pskb, RTN_UNSPEC); |
2cc7d573 HW |
163 | } |
164 | return 0; | |
165 | } | |
166 | ||
422c346f PM |
167 | unsigned int nf_ip_checksum(struct sk_buff *skb, unsigned int hook, |
168 | unsigned int dataoff, u_int8_t protocol) | |
169 | { | |
170 | struct iphdr *iph = skb->nh.iph; | |
171 | unsigned int csum = 0; | |
172 | ||
173 | switch (skb->ip_summed) { | |
84fa7933 | 174 | case CHECKSUM_COMPLETE: |
422c346f PM |
175 | if (hook != NF_IP_PRE_ROUTING && hook != NF_IP_LOCAL_IN) |
176 | break; | |
177 | if ((protocol == 0 && !(u16)csum_fold(skb->csum)) || | |
178 | !csum_tcpudp_magic(iph->saddr, iph->daddr, | |
179 | skb->len - dataoff, protocol, | |
180 | skb->csum)) { | |
181 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
182 | break; | |
183 | } | |
184 | /* fall through */ | |
185 | case CHECKSUM_NONE: | |
186 | if (protocol == 0) | |
187 | skb->csum = 0; | |
188 | else | |
189 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, | |
190 | skb->len - dataoff, | |
191 | protocol, 0); | |
192 | csum = __skb_checksum_complete(skb); | |
193 | } | |
194 | return csum; | |
195 | } | |
196 | ||
197 | EXPORT_SYMBOL(nf_ip_checksum); | |
198 | ||
bce8032e PM |
199 | static struct nf_afinfo nf_ip_afinfo = { |
200 | .family = AF_INET, | |
422c346f | 201 | .checksum = nf_ip_checksum, |
bce8032e PM |
202 | .saveroute = nf_ip_saveroute, |
203 | .reroute = nf_ip_reroute, | |
204 | .route_key_size = sizeof(struct ip_rt_info), | |
2cc7d573 HW |
205 | }; |
206 | ||
65b4b4e8 | 207 | static int ipv4_netfilter_init(void) |
2cc7d573 | 208 | { |
bce8032e | 209 | return nf_register_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
210 | } |
211 | ||
65b4b4e8 | 212 | static void ipv4_netfilter_fini(void) |
2cc7d573 | 213 | { |
bce8032e | 214 | nf_unregister_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
215 | } |
216 | ||
65b4b4e8 AM |
217 | module_init(ipv4_netfilter_init); |
218 | module_exit(ipv4_netfilter_fini); |