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Commit | Line | Data |
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1 | /* | |
2 | * IPv6 specific functions of netfilter core | |
3 | * | |
4 | * Rusty Russell (C) 2000 -- This code is GPL. | |
5 | * Patrick McHardy (C) 2006-2012 | |
6 | */ | |
7 | #include <linux/kernel.h> | |
8 | #include <linux/init.h> | |
9 | #include <linux/ipv6.h> | |
10 | #include <linux/netfilter.h> | |
11 | #include <linux/netfilter_ipv6.h> | |
12 | #include <linux/export.h> | |
13 | #include <net/addrconf.h> | |
14 | #include <net/dst.h> | |
15 | #include <net/ipv6.h> | |
16 | #include <net/ip6_route.h> | |
17 | #include <net/xfrm.h> | |
18 | #include <net/ip6_checksum.h> | |
19 | #include <net/netfilter/nf_queue.h> | |
20 | ||
21 | int ip6_route_me_harder(struct net *net, struct sk_buff *skb) | |
22 | { | |
23 | const struct ipv6hdr *iph = ipv6_hdr(skb); | |
24 | unsigned int hh_len; | |
25 | struct dst_entry *dst; | |
26 | struct flowi6 fl6 = { | |
27 | .flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0, | |
28 | .flowi6_mark = skb->mark, | |
29 | .flowi6_uid = sock_net_uid(net, skb->sk), | |
30 | .daddr = iph->daddr, | |
31 | .saddr = iph->saddr, | |
32 | }; | |
33 | int err; | |
34 | ||
35 | dst = ip6_route_output(net, skb->sk, &fl6); | |
36 | err = dst->error; | |
37 | if (err) { | |
38 | IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); | |
39 | net_dbg_ratelimited("ip6_route_me_harder: No more route\n"); | |
40 | dst_release(dst); | |
41 | return err; | |
42 | } | |
43 | ||
44 | /* Drop old route. */ | |
45 | skb_dst_drop(skb); | |
46 | ||
47 | skb_dst_set(skb, dst); | |
48 | ||
49 | #ifdef CONFIG_XFRM | |
50 | if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && | |
51 | xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) { | |
52 | skb_dst_set(skb, NULL); | |
53 | dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), skb->sk, 0); | |
54 | if (IS_ERR(dst)) | |
55 | return PTR_ERR(dst); | |
56 | skb_dst_set(skb, dst); | |
57 | } | |
58 | #endif | |
59 | ||
60 | /* Change in oif may mean change in hh_len. */ | |
61 | hh_len = skb_dst(skb)->dev->hard_header_len; | |
62 | if (skb_headroom(skb) < hh_len && | |
63 | pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)), | |
64 | 0, GFP_ATOMIC)) | |
65 | return -ENOMEM; | |
66 | ||
67 | return 0; | |
68 | } | |
69 | EXPORT_SYMBOL(ip6_route_me_harder); | |
70 | ||
71 | /* | |
72 | * Extra routing may needed on local out, as the QUEUE target never | |
73 | * returns control to the table. | |
74 | */ | |
75 | ||
76 | struct ip6_rt_info { | |
77 | struct in6_addr daddr; | |
78 | struct in6_addr saddr; | |
79 | u_int32_t mark; | |
80 | }; | |
81 | ||
82 | static void nf_ip6_saveroute(const struct sk_buff *skb, | |
83 | struct nf_queue_entry *entry) | |
84 | { | |
85 | struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); | |
86 | ||
87 | if (entry->state.hook == NF_INET_LOCAL_OUT) { | |
88 | const struct ipv6hdr *iph = ipv6_hdr(skb); | |
89 | ||
90 | rt_info->daddr = iph->daddr; | |
91 | rt_info->saddr = iph->saddr; | |
92 | rt_info->mark = skb->mark; | |
93 | } | |
94 | } | |
95 | ||
96 | static int nf_ip6_reroute(struct net *net, struct sk_buff *skb, | |
97 | const struct nf_queue_entry *entry) | |
98 | { | |
99 | struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry); | |
100 | ||
101 | if (entry->state.hook == NF_INET_LOCAL_OUT) { | |
102 | const struct ipv6hdr *iph = ipv6_hdr(skb); | |
103 | if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) || | |
104 | !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) || | |
105 | skb->mark != rt_info->mark) | |
106 | return ip6_route_me_harder(net, skb); | |
107 | } | |
108 | return 0; | |
109 | } | |
110 | ||
111 | static int nf_ip6_route(struct net *net, struct dst_entry **dst, | |
112 | struct flowi *fl, bool strict) | |
113 | { | |
114 | static const struct ipv6_pinfo fake_pinfo; | |
115 | static const struct inet_sock fake_sk = { | |
116 | /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */ | |
117 | .sk.sk_bound_dev_if = 1, | |
118 | .pinet6 = (struct ipv6_pinfo *) &fake_pinfo, | |
119 | }; | |
120 | const void *sk = strict ? &fake_sk : NULL; | |
121 | struct dst_entry *result; | |
122 | int err; | |
123 | ||
124 | result = ip6_route_output(net, sk, &fl->u.ip6); | |
125 | err = result->error; | |
126 | if (err) | |
127 | dst_release(result); | |
128 | else | |
129 | *dst = result; | |
130 | return err; | |
131 | } | |
132 | ||
133 | __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook, | |
134 | unsigned int dataoff, u_int8_t protocol) | |
135 | { | |
136 | const struct ipv6hdr *ip6h = ipv6_hdr(skb); | |
137 | __sum16 csum = 0; | |
138 | ||
139 | switch (skb->ip_summed) { | |
140 | case CHECKSUM_COMPLETE: | |
141 | if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) | |
142 | break; | |
143 | if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, | |
144 | skb->len - dataoff, protocol, | |
145 | csum_sub(skb->csum, | |
146 | skb_checksum(skb, 0, | |
147 | dataoff, 0)))) { | |
148 | skb->ip_summed = CHECKSUM_UNNECESSARY; | |
149 | break; | |
150 | } | |
151 | /* fall through */ | |
152 | case CHECKSUM_NONE: | |
153 | skb->csum = ~csum_unfold( | |
154 | csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, | |
155 | skb->len - dataoff, | |
156 | protocol, | |
157 | csum_sub(0, | |
158 | skb_checksum(skb, 0, | |
159 | dataoff, 0)))); | |
160 | csum = __skb_checksum_complete(skb); | |
161 | } | |
162 | return csum; | |
163 | } | |
164 | EXPORT_SYMBOL(nf_ip6_checksum); | |
165 | ||
166 | static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook, | |
167 | unsigned int dataoff, unsigned int len, | |
168 | u_int8_t protocol) | |
169 | { | |
170 | const struct ipv6hdr *ip6h = ipv6_hdr(skb); | |
171 | __wsum hsum; | |
172 | __sum16 csum = 0; | |
173 | ||
174 | switch (skb->ip_summed) { | |
175 | case CHECKSUM_COMPLETE: | |
176 | if (len == skb->len - dataoff) | |
177 | return nf_ip6_checksum(skb, hook, dataoff, protocol); | |
178 | /* fall through */ | |
179 | case CHECKSUM_NONE: | |
180 | hsum = skb_checksum(skb, 0, dataoff, 0); | |
181 | skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr, | |
182 | &ip6h->daddr, | |
183 | skb->len - dataoff, | |
184 | protocol, | |
185 | csum_sub(0, hsum))); | |
186 | skb->ip_summed = CHECKSUM_NONE; | |
187 | return __skb_checksum_complete_head(skb, dataoff + len); | |
188 | } | |
189 | return csum; | |
190 | }; | |
191 | ||
192 | static const struct nf_ipv6_ops ipv6ops = { | |
193 | .chk_addr = ipv6_chk_addr, | |
194 | .route_input = ip6_route_input, | |
195 | .fragment = ip6_fragment | |
196 | }; | |
197 | ||
198 | static const struct nf_afinfo nf_ip6_afinfo = { | |
199 | .family = AF_INET6, | |
200 | .checksum = nf_ip6_checksum, | |
201 | .checksum_partial = nf_ip6_checksum_partial, | |
202 | .route = nf_ip6_route, | |
203 | .saveroute = nf_ip6_saveroute, | |
204 | .reroute = nf_ip6_reroute, | |
205 | .route_key_size = sizeof(struct ip6_rt_info), | |
206 | }; | |
207 | ||
208 | int __init ipv6_netfilter_init(void) | |
209 | { | |
210 | RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops); | |
211 | return nf_register_afinfo(&nf_ip6_afinfo); | |
212 | } | |
213 | ||
214 | /* This can be called from inet6_init() on errors, so it cannot | |
215 | * be marked __exit. -DaveM | |
216 | */ | |
217 | void ipv6_netfilter_fini(void) | |
218 | { | |
219 | RCU_INIT_POINTER(nf_ipv6_ops, NULL); | |
220 | nf_unregister_afinfo(&nf_ip6_afinfo); | |
221 | } |