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