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> |
5a0e3ad6 | 7 | #include <linux/gfp.h> |
020b4c12 | 8 | #include <net/route.h> |
3e3850e9 PM |
9 | #include <net/xfrm.h> |
10 | #include <net/ip.h> | |
c01cd429 | 11 | #include <net/netfilter/nf_queue.h> |
020b4c12 HW |
12 | |
13 | /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ | |
3db05fea | 14 | int ip_route_me_harder(struct sk_buff *skb, unsigned addr_type) |
020b4c12 | 15 | { |
adf30907 | 16 | struct net *net = dev_net(skb_dst(skb)->dev); |
3db05fea | 17 | const struct iphdr *iph = ip_hdr(skb); |
020b4c12 | 18 | struct rtable *rt; |
9d6ec938 | 19 | struct flowi4 fl4 = {}; |
7fee226a | 20 | unsigned long orefdst; |
020b4c12 | 21 | unsigned int hh_len; |
c68b8b68 | 22 | unsigned int type; |
020b4c12 | 23 | |
b21f8901 | 24 | type = inet_addr_type(net, iph->saddr); |
86b08d86 KK |
25 | if (skb->sk && inet_sk(skb->sk)->transparent) |
26 | type = RTN_LOCAL; | |
b4c4ed17 | 27 | if (addr_type == RTN_UNSPEC) |
c68b8b68 | 28 | addr_type = type; |
b4c4ed17 | 29 | |
020b4c12 | 30 | /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause |
6e23ae2a | 31 | * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook. |
020b4c12 | 32 | */ |
b4c4ed17 | 33 | if (addr_type == RTN_LOCAL) { |
9d6ec938 | 34 | fl4.daddr = iph->daddr; |
c68b8b68 | 35 | if (type == RTN_LOCAL) |
9d6ec938 DM |
36 | fl4.saddr = iph->saddr; |
37 | fl4.flowi4_tos = RT_TOS(iph->tos); | |
38 | fl4.flowi4_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0; | |
39 | fl4.flowi4_mark = skb->mark; | |
40 | fl4.flowi4_flags = skb->sk ? inet_sk_flowi_flags(skb->sk) : 0; | |
41 | rt = ip_route_output_key(net, &fl4); | |
b23dd4fe | 42 | if (IS_ERR(rt)) |
020b4c12 HW |
43 | return -1; |
44 | ||
45 | /* Drop old route. */ | |
adf30907 | 46 | skb_dst_drop(skb); |
d8d1f30b | 47 | skb_dst_set(skb, &rt->dst); |
020b4c12 HW |
48 | } else { |
49 | /* non-local src, find valid iif to satisfy | |
50 | * rp-filter when calling ip_route_input. */ | |
9d6ec938 DM |
51 | fl4.daddr = iph->saddr; |
52 | rt = ip_route_output_key(net, &fl4); | |
b23dd4fe | 53 | if (IS_ERR(rt)) |
020b4c12 HW |
54 | return -1; |
55 | ||
7fee226a | 56 | orefdst = skb->_skb_refdst; |
3db05fea | 57 | if (ip_route_input(skb, iph->daddr, iph->saddr, |
d8d1f30b CG |
58 | RT_TOS(iph->tos), rt->dst.dev) != 0) { |
59 | dst_release(&rt->dst); | |
020b4c12 HW |
60 | return -1; |
61 | } | |
d8d1f30b | 62 | dst_release(&rt->dst); |
7fee226a | 63 | refdst_drop(orefdst); |
020b4c12 | 64 | } |
e905a9ed | 65 | |
adf30907 | 66 | if (skb_dst(skb)->error) |
020b4c12 HW |
67 | return -1; |
68 | ||
3e3850e9 | 69 | #ifdef CONFIG_XFRM |
3db05fea | 70 | if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) && |
9d6ec938 | 71 | xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) { |
adf30907 ED |
72 | struct dst_entry *dst = skb_dst(skb); |
73 | skb_dst_set(skb, NULL); | |
9d6ec938 | 74 | dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), skb->sk, 0); |
452edd59 | 75 | if (IS_ERR(dst)) |
3e3850e9 | 76 | return -1; |
adf30907 ED |
77 | skb_dst_set(skb, dst); |
78 | } | |
3e3850e9 PM |
79 | #endif |
80 | ||
020b4c12 | 81 | /* Change in oif may mean change in hh_len. */ |
adf30907 | 82 | hh_len = skb_dst(skb)->dev->hard_header_len; |
3db05fea HX |
83 | if (skb_headroom(skb) < hh_len && |
84 | pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC)) | |
2ca7b0ac | 85 | return -1; |
020b4c12 HW |
86 | |
87 | return 0; | |
88 | } | |
89 | EXPORT_SYMBOL(ip_route_me_harder); | |
2cc7d573 | 90 | |
ee68cea2 | 91 | #ifdef CONFIG_XFRM |
3db05fea | 92 | int ip_xfrm_me_harder(struct sk_buff *skb) |
ee68cea2 PM |
93 | { |
94 | struct flowi fl; | |
95 | unsigned int hh_len; | |
96 | struct dst_entry *dst; | |
97 | ||
3db05fea | 98 | if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) |
ee68cea2 | 99 | return 0; |
3db05fea | 100 | if (xfrm_decode_session(skb, &fl, AF_INET) < 0) |
ee68cea2 PM |
101 | return -1; |
102 | ||
adf30907 | 103 | dst = skb_dst(skb); |
ee68cea2 PM |
104 | if (dst->xfrm) |
105 | dst = ((struct xfrm_dst *)dst)->route; | |
106 | dst_hold(dst); | |
107 | ||
452edd59 DM |
108 | dst = xfrm_lookup(dev_net(dst->dev), dst, &fl, skb->sk, 0); |
109 | if (IS_ERR(dst)) | |
ee68cea2 PM |
110 | return -1; |
111 | ||
adf30907 ED |
112 | skb_dst_drop(skb); |
113 | skb_dst_set(skb, dst); | |
ee68cea2 PM |
114 | |
115 | /* Change in oif may mean change in hh_len. */ | |
adf30907 | 116 | hh_len = skb_dst(skb)->dev->hard_header_len; |
3db05fea HX |
117 | if (skb_headroom(skb) < hh_len && |
118 | pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC)) | |
2ca7b0ac | 119 | return -1; |
ee68cea2 PM |
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 | 136 | u_int8_t tos; |
5f145e44 | 137 | u_int32_t mark; |
2cc7d573 HW |
138 | }; |
139 | ||
02f014d8 PM |
140 | static void nf_ip_saveroute(const struct sk_buff *skb, |
141 | struct nf_queue_entry *entry) | |
2cc7d573 | 142 | { |
02f014d8 | 143 | struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
2cc7d573 | 144 | |
02f014d8 | 145 | if (entry->hook == NF_INET_LOCAL_OUT) { |
eddc9ec5 | 146 | const struct iphdr *iph = ip_hdr(skb); |
2cc7d573 HW |
147 | |
148 | rt_info->tos = iph->tos; | |
149 | rt_info->daddr = iph->daddr; | |
150 | rt_info->saddr = iph->saddr; | |
5f145e44 | 151 | rt_info->mark = skb->mark; |
2cc7d573 HW |
152 | } |
153 | } | |
154 | ||
02f014d8 PM |
155 | static int nf_ip_reroute(struct sk_buff *skb, |
156 | const struct nf_queue_entry *entry) | |
2cc7d573 | 157 | { |
02f014d8 | 158 | const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
2cc7d573 | 159 | |
02f014d8 | 160 | if (entry->hook == NF_INET_LOCAL_OUT) { |
3db05fea | 161 | const struct iphdr *iph = ip_hdr(skb); |
2cc7d573 | 162 | |
f64f9e71 JP |
163 | if (!(iph->tos == rt_info->tos && |
164 | skb->mark == rt_info->mark && | |
165 | iph->daddr == rt_info->daddr && | |
166 | iph->saddr == rt_info->saddr)) | |
3db05fea | 167 | return ip_route_me_harder(skb, RTN_UNSPEC); |
2cc7d573 HW |
168 | } |
169 | return 0; | |
170 | } | |
171 | ||
b51655b9 | 172 | __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook, |
422c346f PM |
173 | unsigned int dataoff, u_int8_t protocol) |
174 | { | |
eddc9ec5 | 175 | const struct iphdr *iph = ip_hdr(skb); |
b51655b9 | 176 | __sum16 csum = 0; |
422c346f PM |
177 | |
178 | switch (skb->ip_summed) { | |
84fa7933 | 179 | case CHECKSUM_COMPLETE: |
6e23ae2a | 180 | if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) |
422c346f | 181 | break; |
d3bc23e7 | 182 | if ((protocol == 0 && !csum_fold(skb->csum)) || |
422c346f | 183 | !csum_tcpudp_magic(iph->saddr, iph->daddr, |
e905a9ed | 184 | skb->len - dataoff, protocol, |
422c346f PM |
185 | skb->csum)) { |
186 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
187 | break; | |
188 | } | |
189 | /* fall through */ | |
190 | case CHECKSUM_NONE: | |
191 | if (protocol == 0) | |
192 | skb->csum = 0; | |
193 | else | |
194 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, | |
195 | skb->len - dataoff, | |
196 | protocol, 0); | |
197 | csum = __skb_checksum_complete(skb); | |
198 | } | |
199 | return csum; | |
200 | } | |
422c346f PM |
201 | EXPORT_SYMBOL(nf_ip_checksum); |
202 | ||
d63a6507 PM |
203 | static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook, |
204 | unsigned int dataoff, unsigned int len, | |
205 | u_int8_t protocol) | |
206 | { | |
207 | const struct iphdr *iph = ip_hdr(skb); | |
208 | __sum16 csum = 0; | |
209 | ||
210 | switch (skb->ip_summed) { | |
211 | case CHECKSUM_COMPLETE: | |
212 | if (len == skb->len - dataoff) | |
213 | return nf_ip_checksum(skb, hook, dataoff, protocol); | |
214 | /* fall through */ | |
215 | case CHECKSUM_NONE: | |
216 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol, | |
217 | skb->len - dataoff, 0); | |
218 | skb->ip_summed = CHECKSUM_NONE; | |
c86ee67c | 219 | return __skb_checksum_complete_head(skb, dataoff + len); |
d63a6507 PM |
220 | } |
221 | return csum; | |
222 | } | |
223 | ||
1841a4c7 PM |
224 | static int nf_ip_route(struct dst_entry **dst, struct flowi *fl) |
225 | { | |
9d6ec938 | 226 | struct rtable *rt = ip_route_output_key(&init_net, &fl->u.ip4); |
b23dd4fe DM |
227 | if (IS_ERR(rt)) |
228 | return PTR_ERR(rt); | |
229 | *dst = &rt->dst; | |
230 | return 0; | |
1841a4c7 PM |
231 | } |
232 | ||
1e796fda | 233 | static const struct nf_afinfo nf_ip_afinfo = { |
d63a6507 PM |
234 | .family = AF_INET, |
235 | .checksum = nf_ip_checksum, | |
236 | .checksum_partial = nf_ip_checksum_partial, | |
237 | .route = nf_ip_route, | |
238 | .saveroute = nf_ip_saveroute, | |
239 | .reroute = nf_ip_reroute, | |
240 | .route_key_size = sizeof(struct ip_rt_info), | |
2cc7d573 HW |
241 | }; |
242 | ||
65b4b4e8 | 243 | static int ipv4_netfilter_init(void) |
2cc7d573 | 244 | { |
bce8032e | 245 | return nf_register_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
246 | } |
247 | ||
65b4b4e8 | 248 | static void ipv4_netfilter_fini(void) |
2cc7d573 | 249 | { |
bce8032e | 250 | nf_unregister_afinfo(&nf_ip_afinfo); |
2cc7d573 HW |
251 | } |
252 | ||
65b4b4e8 AM |
253 | module_init(ipv4_netfilter_init); |
254 | module_exit(ipv4_netfilter_fini); | |
4f536522 PM |
255 | |
256 | #ifdef CONFIG_SYSCTL | |
257 | struct ctl_path nf_net_ipv4_netfilter_sysctl_path[] = { | |
f8572d8f EB |
258 | { .procname = "net", }, |
259 | { .procname = "ipv4", }, | |
260 | { .procname = "netfilter", }, | |
4f536522 PM |
261 | { } |
262 | }; | |
263 | EXPORT_SYMBOL_GPL(nf_net_ipv4_netfilter_sysctl_path); | |
264 | #endif /* CONFIG_SYSCTL */ |