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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/netfilter/nf_queue.h>
19#include <net/netfilter/nf_conntrack_bridge.h>
20#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
21#include "../bridge/br_private.h"
22
23int ip6_route_me_harder(struct net *net, struct sock *sk_partial, struct sk_buff *skb)
24{
25 const struct ipv6hdr *iph = ipv6_hdr(skb);
26 struct sock *sk = sk_to_full_sk(sk_partial);
27 struct net_device *dev = skb_dst(skb)->dev;
28 struct flow_keys flkeys;
29 unsigned int hh_len;
30 struct dst_entry *dst;
31 int strict = (ipv6_addr_type(&iph->daddr) &
32 (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
33 struct flowi6 fl6 = {
34 .flowi6_l3mdev = l3mdev_master_ifindex(dev),
35 .flowi6_mark = skb->mark,
36 .flowi6_uid = sock_net_uid(net, sk),
37 .daddr = iph->daddr,
38 .saddr = iph->saddr,
39 .flowlabel = ip6_flowinfo(iph),
40 };
41 int err;
42
43 if (sk && sk->sk_bound_dev_if)
44 fl6.flowi6_oif = sk->sk_bound_dev_if;
45 else if (strict)
46 fl6.flowi6_oif = dev->ifindex;
47
48 fib6_rules_early_flow_dissect(net, skb, &fl6, &flkeys);
49 dst = ip6_route_output(net, sk, &fl6);
50 err = dst->error;
51 if (err) {
52 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
53 net_dbg_ratelimited("ip6_route_me_harder: No more route\n");
54 dst_release(dst);
55 return err;
56 }
57
58 /* Drop old route. */
59 skb_dst_drop(skb);
60
61 skb_dst_set(skb, dst);
62
63#ifdef CONFIG_XFRM
64 if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
65 xfrm_decode_session(net, skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
66 skb_dst_set(skb, NULL);
67 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
68 if (IS_ERR(dst))
69 return PTR_ERR(dst);
70 skb_dst_set(skb, dst);
71 }
72#endif
73
74 /* Change in oif may mean change in hh_len. */
75 hh_len = skb_dst(skb)->dev->hard_header_len;
76 if (skb_headroom(skb) < hh_len &&
77 pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
78 0, GFP_ATOMIC))
79 return -ENOMEM;
80
81 return 0;
82}
83EXPORT_SYMBOL(ip6_route_me_harder);
84
85static int nf_ip6_reroute(struct sk_buff *skb,
86 const struct nf_queue_entry *entry)
87{
88 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
89
90 if (entry->state.hook == NF_INET_LOCAL_OUT) {
91 const struct ipv6hdr *iph = ipv6_hdr(skb);
92 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
93 !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
94 skb->mark != rt_info->mark)
95 return ip6_route_me_harder(entry->state.net, entry->state.sk, skb);
96 }
97 return 0;
98}
99
100int __nf_ip6_route(struct net *net, struct dst_entry **dst,
101 struct flowi *fl, bool strict)
102{
103 static const struct ipv6_pinfo fake_pinfo;
104 static const struct inet_sock fake_sk = {
105 /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */
106 .sk.sk_bound_dev_if = 1,
107 .pinet6 = (struct ipv6_pinfo *) &fake_pinfo,
108 };
109 const void *sk = strict ? &fake_sk : NULL;
110 struct dst_entry *result;
111 int err;
112
113 result = ip6_route_output(net, sk, &fl->u.ip6);
114 err = result->error;
115 if (err)
116 dst_release(result);
117 else
118 *dst = result;
119 return err;
120}
121EXPORT_SYMBOL_GPL(__nf_ip6_route);
122
123int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
124 struct nf_bridge_frag_data *data,
125 int (*output)(struct net *, struct sock *sk,
126 const struct nf_bridge_frag_data *data,
127 struct sk_buff *))
128{
129 int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
130 u8 tstamp_type = skb->tstamp_type;
131 ktime_t tstamp = skb->tstamp;
132 struct ip6_frag_state state;
133 u8 *prevhdr, nexthdr = 0;
134 unsigned int mtu, hlen;
135 int hroom, err = 0;
136 __be32 frag_id;
137
138 err = ip6_find_1stfragopt(skb, &prevhdr);
139 if (err < 0)
140 goto blackhole;
141 hlen = err;
142 nexthdr = *prevhdr;
143
144 mtu = skb->dev->mtu;
145 if (frag_max_size > mtu ||
146 frag_max_size < IPV6_MIN_MTU)
147 goto blackhole;
148
149 mtu = frag_max_size;
150 if (mtu < hlen + sizeof(struct frag_hdr) + 8)
151 goto blackhole;
152 mtu -= hlen + sizeof(struct frag_hdr);
153
154 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
155 &ipv6_hdr(skb)->saddr);
156
157 if (skb->ip_summed == CHECKSUM_PARTIAL &&
158 (err = skb_checksum_help(skb)))
159 goto blackhole;
160
161 hroom = LL_RESERVED_SPACE(skb->dev);
162 if (skb_has_frag_list(skb)) {
163 unsigned int first_len = skb_pagelen(skb);
164 struct ip6_fraglist_iter iter;
165 struct sk_buff *frag2;
166
167 if (first_len - hlen > mtu ||
168 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
169 goto blackhole;
170
171 if (skb_cloned(skb))
172 goto slow_path;
173
174 skb_walk_frags(skb, frag2) {
175 if (frag2->len > mtu ||
176 skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))
177 goto blackhole;
178
179 /* Partially cloned skb? */
180 if (skb_shared(frag2))
181 goto slow_path;
182 }
183
184 err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
185 &iter);
186 if (err < 0)
187 goto blackhole;
188
189 for (;;) {
190 /* Prepare header of the next frame,
191 * before previous one went down.
192 */
193 if (iter.frag)
194 ip6_fraglist_prepare(skb, &iter);
195
196 skb_set_delivery_time(skb, tstamp, tstamp_type);
197 err = output(net, sk, data, skb);
198 if (err || !iter.frag)
199 break;
200
201 skb = ip6_fraglist_next(&iter);
202 }
203
204 kfree(iter.tmp_hdr);
205 if (!err)
206 return 0;
207
208 kfree_skb_list(iter.frag);
209 return err;
210 }
211slow_path:
212 /* This is a linearized skbuff, the original geometry is lost for us.
213 * This may also be a clone skbuff, we could preserve the geometry for
214 * the copies but probably not worth the effort.
215 */
216 ip6_frag_init(skb, hlen, mtu, skb->dev->needed_tailroom,
217 LL_RESERVED_SPACE(skb->dev), prevhdr, nexthdr, frag_id,
218 &state);
219
220 while (state.left > 0) {
221 struct sk_buff *skb2;
222
223 skb2 = ip6_frag_next(skb, &state);
224 if (IS_ERR(skb2)) {
225 err = PTR_ERR(skb2);
226 goto blackhole;
227 }
228
229 skb_set_delivery_time(skb2, tstamp, tstamp_type);
230 err = output(net, sk, data, skb2);
231 if (err)
232 goto blackhole;
233 }
234 consume_skb(skb);
235 return err;
236
237blackhole:
238 kfree_skb(skb);
239 return 0;
240}
241EXPORT_SYMBOL_GPL(br_ip6_fragment);
242
243static const struct nf_ipv6_ops ipv6ops = {
244#if IS_MODULE(CONFIG_IPV6)
245 .chk_addr = ipv6_chk_addr,
246 .route_me_harder = ip6_route_me_harder,
247 .dev_get_saddr = ipv6_dev_get_saddr,
248 .route = __nf_ip6_route,
249#if IS_ENABLED(CONFIG_SYN_COOKIES)
250 .cookie_init_sequence = __cookie_v6_init_sequence,
251 .cookie_v6_check = __cookie_v6_check,
252#endif
253#endif
254 .route_input = ip6_route_input,
255 .fragment = ip6_fragment,
256 .reroute = nf_ip6_reroute,
257#if IS_MODULE(CONFIG_IPV6)
258 .br_fragment = br_ip6_fragment,
259#endif
260};
261
262int __init ipv6_netfilter_init(void)
263{
264 RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops);
265 return 0;
266}
267
268/* This can be called from inet6_init() on errors, so it cannot
269 * be marked __exit. -DaveM
270 */
271void ipv6_netfilter_fini(void)
272{
273 RCU_INIT_POINTER(nf_ipv6_ops, NULL);
274}
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
14int 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}
52EXPORT_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
59struct ip6_rt_info {
60 struct in6_addr daddr;
61 struct in6_addr saddr;
62 u_int32_t mark;
63};
64
65static 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
79static 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
94static 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
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}
147EXPORT_SYMBOL(nf_ip6_checksum);
148
149static __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
175static 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
185int __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 */
193void ipv6_netfilter_fini(void)
194{
195 nf_unregister_afinfo(&nf_ip6_afinfo);
196}