Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
os
linux
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 sk_buff *skb)
24{
25 const struct ipv6hdr *iph = ipv6_hdr(skb);
26 struct sock *sk = sk_to_full_sk(skb->sk);
27 unsigned int hh_len;
28 struct dst_entry *dst;
29 int strict = (ipv6_addr_type(&iph->daddr) &
30 (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
31 struct flowi6 fl6 = {
32 .flowi6_oif = sk && sk->sk_bound_dev_if ? sk->sk_bound_dev_if :
33 strict ? skb_dst(skb)->dev->ifindex : 0,
34 .flowi6_mark = skb->mark,
35 .flowi6_uid = sock_net_uid(net, sk),
36 .daddr = iph->daddr,
37 .saddr = iph->saddr,
38 };
39 int err;
40
41 dst = ip6_route_output(net, sk, &fl6);
42 err = dst->error;
43 if (err) {
44 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
45 net_dbg_ratelimited("ip6_route_me_harder: No more route\n");
46 dst_release(dst);
47 return err;
48 }
49
50 /* Drop old route. */
51 skb_dst_drop(skb);
52
53 skb_dst_set(skb, dst);
54
55#ifdef CONFIG_XFRM
56 if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
57 xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
58 skb_dst_set(skb, NULL);
59 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
60 if (IS_ERR(dst))
61 return PTR_ERR(dst);
62 skb_dst_set(skb, dst);
63 }
64#endif
65
66 /* Change in oif may mean change in hh_len. */
67 hh_len = skb_dst(skb)->dev->hard_header_len;
68 if (skb_headroom(skb) < hh_len &&
69 pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
70 0, GFP_ATOMIC))
71 return -ENOMEM;
72
73 return 0;
74}
75EXPORT_SYMBOL(ip6_route_me_harder);
76
77static int nf_ip6_reroute(struct sk_buff *skb,
78 const struct nf_queue_entry *entry)
79{
80 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
81
82 if (entry->state.hook == NF_INET_LOCAL_OUT) {
83 const struct ipv6hdr *iph = ipv6_hdr(skb);
84 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
85 !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
86 skb->mark != rt_info->mark)
87 return ip6_route_me_harder(entry->state.net, skb);
88 }
89 return 0;
90}
91
92int __nf_ip6_route(struct net *net, struct dst_entry **dst,
93 struct flowi *fl, bool strict)
94{
95 static const struct ipv6_pinfo fake_pinfo;
96 static const struct inet_sock fake_sk = {
97 /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */
98 .sk.sk_bound_dev_if = 1,
99 .pinet6 = (struct ipv6_pinfo *) &fake_pinfo,
100 };
101 const void *sk = strict ? &fake_sk : NULL;
102 struct dst_entry *result;
103 int err;
104
105 result = ip6_route_output(net, sk, &fl->u.ip6);
106 err = result->error;
107 if (err)
108 dst_release(result);
109 else
110 *dst = result;
111 return err;
112}
113EXPORT_SYMBOL_GPL(__nf_ip6_route);
114
115int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
116 struct nf_bridge_frag_data *data,
117 int (*output)(struct net *, struct sock *sk,
118 const struct nf_bridge_frag_data *data,
119 struct sk_buff *))
120{
121 int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
122 struct ip6_frag_state state;
123 u8 *prevhdr, nexthdr = 0;
124 unsigned int mtu, hlen;
125 int hroom, err = 0;
126 __be32 frag_id;
127
128 err = ip6_find_1stfragopt(skb, &prevhdr);
129 if (err < 0)
130 goto blackhole;
131 hlen = err;
132 nexthdr = *prevhdr;
133
134 mtu = skb->dev->mtu;
135 if (frag_max_size > mtu ||
136 frag_max_size < IPV6_MIN_MTU)
137 goto blackhole;
138
139 mtu = frag_max_size;
140 if (mtu < hlen + sizeof(struct frag_hdr) + 8)
141 goto blackhole;
142 mtu -= hlen + sizeof(struct frag_hdr);
143
144 frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
145 &ipv6_hdr(skb)->saddr);
146
147 if (skb->ip_summed == CHECKSUM_PARTIAL &&
148 (err = skb_checksum_help(skb)))
149 goto blackhole;
150
151 hroom = LL_RESERVED_SPACE(skb->dev);
152 if (skb_has_frag_list(skb)) {
153 unsigned int first_len = skb_pagelen(skb);
154 struct ip6_fraglist_iter iter;
155 struct sk_buff *frag2;
156
157 if (first_len - hlen > mtu ||
158 skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))
159 goto blackhole;
160
161 if (skb_cloned(skb))
162 goto slow_path;
163
164 skb_walk_frags(skb, frag2) {
165 if (frag2->len > mtu ||
166 skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))
167 goto blackhole;
168
169 /* Partially cloned skb? */
170 if (skb_shared(frag2))
171 goto slow_path;
172 }
173
174 err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,
175 &iter);
176 if (err < 0)
177 goto blackhole;
178
179 for (;;) {
180 /* Prepare header of the next frame,
181 * before previous one went down.
182 */
183 if (iter.frag)
184 ip6_fraglist_prepare(skb, &iter);
185
186 err = output(net, sk, data, skb);
187 if (err || !iter.frag)
188 break;
189
190 skb = ip6_fraglist_next(&iter);
191 }
192
193 kfree(iter.tmp_hdr);
194 if (!err)
195 return 0;
196
197 kfree_skb_list(iter.frag);
198 return err;
199 }
200slow_path:
201 /* This is a linearized skbuff, the original geometry is lost for us.
202 * This may also be a clone skbuff, we could preserve the geometry for
203 * the copies but probably not worth the effort.
204 */
205 ip6_frag_init(skb, hlen, mtu, skb->dev->needed_tailroom,
206 LL_RESERVED_SPACE(skb->dev), prevhdr, nexthdr, frag_id,
207 &state);
208
209 while (state.left > 0) {
210 struct sk_buff *skb2;
211
212 skb2 = ip6_frag_next(skb, &state);
213 if (IS_ERR(skb2)) {
214 err = PTR_ERR(skb2);
215 goto blackhole;
216 }
217
218 err = output(net, sk, data, skb2);
219 if (err)
220 goto blackhole;
221 }
222 consume_skb(skb);
223 return err;
224
225blackhole:
226 kfree_skb(skb);
227 return 0;
228}
229EXPORT_SYMBOL_GPL(br_ip6_fragment);
230
231static const struct nf_ipv6_ops ipv6ops = {
232#if IS_MODULE(CONFIG_IPV6)
233 .chk_addr = ipv6_chk_addr,
234 .route_me_harder = ip6_route_me_harder,
235 .dev_get_saddr = ipv6_dev_get_saddr,
236 .route = __nf_ip6_route,
237#if IS_ENABLED(CONFIG_SYN_COOKIES)
238 .cookie_init_sequence = __cookie_v6_init_sequence,
239 .cookie_v6_check = __cookie_v6_check,
240#endif
241#endif
242 .route_input = ip6_route_input,
243 .fragment = ip6_fragment,
244 .reroute = nf_ip6_reroute,
245#if IS_MODULE(CONFIG_IPV6) && IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
246 .br_defrag = nf_ct_frag6_gather,
247#endif
248#if IS_MODULE(CONFIG_IPV6)
249 .br_fragment = br_ip6_fragment,
250#endif
251};
252
253int __init ipv6_netfilter_init(void)
254{
255 RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops);
256 return 0;
257}
258
259/* This can be called from inet6_init() on errors, so it cannot
260 * be marked __exit. -DaveM
261 */
262void ipv6_netfilter_fini(void)
263{
264 RCU_INIT_POINTER(nf_ipv6_ops, NULL);
265}