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> |
2ca7b0ac | 6 | #include <linux/skbuff.h> |
020b4c12 | 7 | #include <net/route.h> |
3e3850e9 PM |
8 | #include <net/xfrm.h> |
9 | #include <net/ip.h> | |
c01cd429 | 10 | #include <net/netfilter/nf_queue.h> |
020b4c12 HW |
11 | |
12 | /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ | |
3db05fea | 13 | int ip_route_me_harder(struct sk_buff *skb, unsigned addr_type) |
020b4c12 | 14 | { |
3db05fea | 15 | const struct iphdr *iph = ip_hdr(skb); |
020b4c12 HW |
16 | struct rtable *rt; |
17 | struct flowi fl = {}; | |
18 | struct dst_entry *odst; | |
19 | unsigned int hh_len; | |
c68b8b68 | 20 | unsigned int type; |
020b4c12 | 21 | |
6b175b26 | 22 | type = inet_addr_type(&init_net, iph->saddr); |
b4c4ed17 | 23 | if (addr_type == RTN_UNSPEC) |
c68b8b68 | 24 | addr_type = type; |
b4c4ed17 | 25 | |
020b4c12 | 26 | /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause |
6e23ae2a | 27 | * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook. |
020b4c12 | 28 | */ |
b4c4ed17 | 29 | if (addr_type == RTN_LOCAL) { |
020b4c12 | 30 | fl.nl_u.ip4_u.daddr = iph->daddr; |
c68b8b68 PM |
31 | if (type == RTN_LOCAL) |
32 | fl.nl_u.ip4_u.saddr = iph->saddr; | |
020b4c12 | 33 | fl.nl_u.ip4_u.tos = RT_TOS(iph->tos); |
3db05fea HX |
34 | fl.oif = skb->sk ? skb->sk->sk_bound_dev_if : 0; |
35 | fl.mark = skb->mark; | |
020b4c12 HW |
36 | if (ip_route_output_key(&rt, &fl) != 0) |
37 | return -1; | |
38 | ||
39 | /* Drop old route. */ | |
3db05fea HX |
40 | dst_release(skb->dst); |
41 | skb->dst = &rt->u.dst; | |
020b4c12 HW |
42 | } else { |
43 | /* non-local src, find valid iif to satisfy | |
44 | * rp-filter when calling ip_route_input. */ | |
45 | fl.nl_u.ip4_u.daddr = iph->saddr; | |
46 | if (ip_route_output_key(&rt, &fl) != 0) | |
47 | return -1; | |
48 | ||
3db05fea HX |
49 | odst = skb->dst; |
50 | if (ip_route_input(skb, iph->daddr, iph->saddr, | |
020b4c12 HW |
51 | RT_TOS(iph->tos), rt->u.dst.dev) != 0) { |
52 | dst_release(&rt->u.dst); | |
53 | return -1; | |
54 | } | |
55 | dst_release(&rt->u.dst); | |
56 | dst_release(odst); | |
57 | } | |
e905a9ed | 58 | |
3db05fea | 59 | if (skb->dst->error) |
020b4c12 HW |
60 | return -1; |
61 | ||
3e3850e9 | 62 | #ifdef CONFIG_XFRM |
3db05fea HX |
63 | if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) && |
64 | xfrm_decode_session(skb, &fl, AF_INET) == 0) | |
65 | if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0)) | |
3e3850e9 PM |
66 | return -1; |
67 | #endif | |
68 | ||
020b4c12 | 69 | /* Change in oif may mean change in hh_len. */ |
3db05fea HX |
70 | hh_len = skb->dst->dev->hard_header_len; |
71 | if (skb_headroom(skb) < hh_len && | |
72 | pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC)) | |
2ca7b0ac | 73 | return -1; |
020b4c12 HW |
74 | |
75 | return 0; | |
76 | } | |
77 | EXPORT_SYMBOL(ip_route_me_harder); | |
2cc7d573 | 78 | |
ee68cea2 | 79 | #ifdef CONFIG_XFRM |
3db05fea | 80 | int ip_xfrm_me_harder(struct sk_buff *skb) |
ee68cea2 PM |
81 | { |
82 | struct flowi fl; | |
83 | unsigned int hh_len; | |
84 | struct dst_entry *dst; | |
85 | ||
3db05fea | 86 | if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) |
ee68cea2 | 87 | return 0; |
3db05fea | 88 | if (xfrm_decode_session(skb, &fl, AF_INET) < 0) |
ee68cea2 PM |
89 | return -1; |
90 | ||
3db05fea | 91 | dst = skb->dst; |
ee68cea2 PM |
92 | if (dst->xfrm) |
93 | dst = ((struct xfrm_dst *)dst)->route; | |
94 | dst_hold(dst); | |
95 | ||
3db05fea | 96 | if (xfrm_lookup(&dst, &fl, skb->sk, 0) < 0) |
ee68cea2 PM |
97 | return -1; |
98 | ||
3db05fea HX |
99 | dst_release(skb->dst); |
100 | skb->dst = dst; | |
ee68cea2 PM |
101 | |
102 | /* Change in oif may mean change in hh_len. */ | |
3db05fea HX |
103 | hh_len = skb->dst->dev->hard_header_len; |
104 | if (skb_headroom(skb) < hh_len && | |
105 | pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC)) | |
2ca7b0ac | 106 | return -1; |
ee68cea2 PM |
107 | return 0; |
108 | } | |
109 | EXPORT_SYMBOL(ip_xfrm_me_harder); | |
110 | #endif | |
111 | ||
eb9c7ebe PM |
112 | void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); |
113 | EXPORT_SYMBOL(ip_nat_decode_session); | |
114 | ||
2cc7d573 HW |
115 | /* |
116 | * Extra routing may needed on local out, as the QUEUE target never | |
117 | * returns control to the table. | |
118 | */ | |
119 | ||
120 | struct ip_rt_info { | |
59b8bfd8 AV |
121 | __be32 daddr; |
122 | __be32 saddr; | |
2cc7d573 HW |
123 | u_int8_t tos; |
124 | }; | |
125 | ||
02f014d8 PM |
126 | static void nf_ip_saveroute(const struct sk_buff *skb, |
127 | struct nf_queue_entry *entry) | |
2cc7d573 | 128 | { |
02f014d8 | 129 | struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
2cc7d573 | 130 | |
02f014d8 | 131 | if (entry->hook == NF_INET_LOCAL_OUT) { |
eddc9ec5 | 132 | const struct iphdr *iph = ip_hdr(skb); |
2cc7d573 HW |
133 | |
134 | rt_info->tos = iph->tos; | |
135 | rt_info->daddr = iph->daddr; | |
136 | rt_info->saddr = iph->saddr; | |
137 | } | |
138 | } | |
139 | ||
02f014d8 PM |
140 | static int nf_ip_reroute(struct sk_buff *skb, |
141 | const struct nf_queue_entry *entry) | |
2cc7d573 | 142 | { |
02f014d8 | 143 | const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
2cc7d573 | 144 | |
02f014d8 | 145 | if (entry->hook == NF_INET_LOCAL_OUT) { |
3db05fea | 146 | const struct iphdr *iph = ip_hdr(skb); |
2cc7d573 HW |
147 | |
148 | if (!(iph->tos == rt_info->tos | |
149 | && iph->daddr == rt_info->daddr | |
150 | && iph->saddr == rt_info->saddr)) | |
3db05fea | 151 | return ip_route_me_harder(skb, RTN_UNSPEC); |
2cc7d573 HW |
152 | } |
153 | return 0; | |
154 | } | |
155 | ||
b51655b9 | 156 | __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook, |
422c346f PM |
157 | unsigned int dataoff, u_int8_t protocol) |
158 | { | |
eddc9ec5 | 159 | const struct iphdr *iph = ip_hdr(skb); |
b51655b9 | 160 | __sum16 csum = 0; |
422c346f PM |
161 | |
162 | switch (skb->ip_summed) { | |
84fa7933 | 163 | case CHECKSUM_COMPLETE: |
6e23ae2a | 164 | if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) |
422c346f | 165 | break; |
d3bc23e7 | 166 | if ((protocol == 0 && !csum_fold(skb->csum)) || |
422c346f | 167 | !csum_tcpudp_magic(iph->saddr, iph->daddr, |
e905a9ed | 168 | skb->len - dataoff, protocol, |
422c346f PM |
169 | skb->csum)) { |
170 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
171 | break; | |
172 | } | |
173 | /* fall through */ | |
174 | case CHECKSUM_NONE: | |
175 | if (protocol == 0) | |
176 | skb->csum = 0; | |
177 | else | |
178 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, | |
179 | skb->len - dataoff, | |
180 | protocol, 0); | |
181 | csum = __skb_checksum_complete(skb); | |
182 | } | |
183 | return csum; | |
184 | } | |
185 | ||
186 | EXPORT_SYMBOL(nf_ip_checksum); | |
187 | ||
1841a4c7 PM |
188 | static int nf_ip_route(struct dst_entry **dst, struct flowi *fl) |
189 | { | |
190 | return ip_route_output_key((struct rtable **)dst, fl); | |
191 | } | |
192 | ||
1e796fda | 193 | static const struct nf_afinfo nf_ip_afinfo = { |
bce8032e | 194 | .family = AF_INET, |
422c346f | 195 | .checksum = nf_ip_checksum, |
1841a4c7 | 196 | .route = nf_ip_route, |
bce8032e PM |
197 | .saveroute = nf_ip_saveroute, |
198 | .reroute = nf_ip_reroute, | |
199 | .route_key_size = sizeof(struct ip_rt_info), | |
2cc7d573 HW |
200 | }; |
201 | ||
65b4b4e8 | 202 | static int ipv4_netfilter_init(void) |
2cc7d573 | 203 | { |
bce8032e | 204 | return nf_register_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
205 | } |
206 | ||
65b4b4e8 | 207 | static void ipv4_netfilter_fini(void) |
2cc7d573 | 208 | { |
bce8032e | 209 | nf_unregister_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
210 | } |
211 | ||
65b4b4e8 AM |
212 | module_init(ipv4_netfilter_init); |
213 | module_exit(ipv4_netfilter_fini); | |
4f536522 PM |
214 | |
215 | #ifdef CONFIG_SYSCTL | |
216 | struct ctl_path nf_net_ipv4_netfilter_sysctl_path[] = { | |
217 | { .procname = "net", .ctl_name = CTL_NET, }, | |
218 | { .procname = "ipv4", .ctl_name = NET_IPV4, }, | |
219 | { .procname = "netfilter", .ctl_name = NET_IPV4_NETFILTER, }, | |
220 | { } | |
221 | }; | |
222 | EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path); | |
223 | #endif /* CONFIG_SYSCTL */ |