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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
3 * Copyright (C) 2002 USAGI/WIDE Project
4 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +09005 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
Herbert Xu406ef772007-10-08 17:16:30 -070012#include <linux/if_ether.h>
Herbert Xu36cf9ac2007-11-13 21:40:52 -080013#include <linux/kernel.h>
14#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/skbuff.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/icmpv6.h>
Patrick McHardy16a66772006-01-06 23:01:48 -080017#include <linux/netfilter_ipv6.h>
Herbert Xu36cf9ac2007-11-13 21:40:52 -080018#include <net/dst.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <net/ipv6.h>
David Stevensad0081e2010-12-17 11:42:42 +000020#include <net/ip6_route.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <net/xfrm.h>
22
Masahide NAKAMURAaee5adb2006-08-23 17:57:28 -070023int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
24 u8 **prevhdr)
25{
26 return ip6_find_1stfragopt(skb, prevhdr);
27}
YOSHIFUJI Hideaki71590392007-02-22 22:05:40 +090028EXPORT_SYMBOL(xfrm6_find_1stfragopt);
29
Steffen Klassertdd767852011-10-11 01:44:30 +000030static int xfrm6_local_dontfrag(struct sk_buff *skb)
31{
32 int proto;
33 struct sock *sk = skb->sk;
34
35 if (sk) {
Hannes Frederic Sowa628e3412013-08-14 13:05:23 +020036 if (sk->sk_family != AF_INET6)
37 return 0;
Steffen Klassertdd767852011-10-11 01:44:30 +000038
Hannes Frederic Sowa628e3412013-08-14 13:05:23 +020039 proto = sk->sk_protocol;
Steffen Klassertdd767852011-10-11 01:44:30 +000040 if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
41 return inet6_sk(sk)->dontfrag;
42 }
43
44 return 0;
45}
46
47static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
48{
49 struct flowi6 fl6;
50 struct sock *sk = skb->sk;
51
52 fl6.flowi6_oif = sk->sk_bound_dev_if;
Alexey Dobriyan4e3fd7a2011-11-21 03:39:03 +000053 fl6.daddr = ipv6_hdr(skb)->daddr;
Steffen Klassertdd767852011-10-11 01:44:30 +000054
55 ipv6_local_rxpmtu(sk, &fl6, mtu);
56}
57
Hannes Frederic Sowa628e3412013-08-14 13:05:23 +020058void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
Steffen Klassertdd767852011-10-11 01:44:30 +000059{
60 struct flowi6 fl6;
Hannes Frederic Sowa5d0ff542013-08-18 13:46:57 +020061 const struct ipv6hdr *hdr;
Steffen Klassertdd767852011-10-11 01:44:30 +000062 struct sock *sk = skb->sk;
63
Hannes Frederic Sowa5d0ff542013-08-18 13:46:57 +020064 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
Steffen Klassertdd767852011-10-11 01:44:30 +000065 fl6.fl6_dport = inet_sk(sk)->inet_dport;
Hannes Frederic Sowa5d0ff542013-08-18 13:46:57 +020066 fl6.daddr = hdr->daddr;
Steffen Klassertdd767852011-10-11 01:44:30 +000067
68 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
69}
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071static int xfrm6_tunnel_check_size(struct sk_buff *skb)
72{
73 int mtu, ret = 0;
Eric Dumazetadf30902009-06-02 05:19:30 +000074 struct dst_entry *dst = skb_dst(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76 mtu = dst_mtu(dst);
77 if (mtu < IPV6_MIN_MTU)
78 mtu = IPV6_MIN_MTU;
79
WANG Cong60ff7462014-05-04 16:39:18 -070080 if (!skb->ignore_df && skb->len > mtu) {
Herbert Xu180e4252005-05-23 13:11:07 -070081 skb->dev = dst->dev;
Steffen Klassertca064bd2015-10-19 10:30:05 +020082 skb->protocol = htons(ETH_P_IPV6);
Steffen Klassertdd767852011-10-11 01:44:30 +000083
84 if (xfrm6_local_dontfrag(skb))
85 xfrm6_local_rxpmtu(skb, mtu);
86 else if (skb->sk)
Hannes Frederic Sowa628e3412013-08-14 13:05:23 +020087 xfrm_local_error(skb, mtu);
Steffen Klassertdd767852011-10-11 01:44:30 +000088 else
89 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 ret = -EMSGSIZE;
91 }
92
93 return ret;
94}
95
Herbert Xu36cf9ac2007-11-13 21:40:52 -080096int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070097{
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 int err;
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +090099
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800100 err = xfrm6_tunnel_check_size(skb);
101 if (err)
102 return err;
103
Herbert Xu60d5fcf2007-11-19 18:47:58 -0800104 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
105
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800106 return xfrm6_extract_header(skb);
107}
108
109int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
110{
111 int err;
112
Kazunori MIYAZAWAdf9dcb42008-03-24 14:51:51 -0700113 err = xfrm_inner_extract_output(x, skb);
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800114 if (err)
115 return err;
116
WANG Cong60ff7462014-05-04 16:39:18 -0700117 skb->ignore_df = 1;
Steffen Klassert044a8322015-01-12 13:38:49 +0100118 skb->protocol = htons(ETH_P_IPV6);
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800119
120 return x->outer_mode->output2(x, skb);
121}
122EXPORT_SYMBOL(xfrm6_prepare_output);
123
David Miller7026b1d2015-04-05 22:19:04 -0400124int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
Herbert Xu09b8f7a2006-06-22 03:08:03 -0700125{
Steffen Klassert55967322014-04-07 08:08:52 +0200126 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
Steffen Klassert55967322014-04-07 08:08:52 +0200127
Herbert Xu862b82c2007-11-13 21:43:11 -0800128#ifdef CONFIG_NETFILTER
129 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
130#endif
Herbert Xu09b8f7a2006-06-22 03:08:03 -0700131
David Miller7026b1d2015-04-05 22:19:04 -0400132 return xfrm_output(sk, skb);
Herbert Xu09b8f7a2006-06-22 03:08:03 -0700133}
134
Eric W. Biederman7d8c6e32015-06-12 22:12:04 -0500135static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
136{
137 struct xfrm_state *x = skb_dst(skb)->xfrm;
Eric W. Biedermanb1842ff2015-10-01 11:41:42 -0500138
Eric W. Biederman7d8c6e32015-06-12 22:12:04 -0500139 return x->outer_mode->afinfo->output_finish(sk, skb);
140}
141
Eric W. Biederman0c4b51f2015-09-15 20:04:18 -0500142static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
David Stevensad0081e2010-12-17 11:42:42 +0000143{
144 struct dst_entry *dst = skb_dst(skb);
145 struct xfrm_state *x = dst->xfrm;
Hannes Frederic Sowa5a25cf12013-08-26 12:31:19 +0200146 int mtu;
Herbert Xu93efac32015-09-04 13:21:06 +0800147 bool toobig;
Hannes Frederic Sowa0ea9d5e2013-08-13 04:35:58 +0200148
Steffen Klassert55967322014-04-07 08:08:52 +0200149#ifdef CONFIG_NETFILTER
150 if (!x) {
151 IP6CB(skb)->flags |= IP6SKB_REROUTED;
Eric W. Biederman13206b62015-10-07 16:48:35 -0500152 return dst_output(net, sk, skb);
Steffen Klassert55967322014-04-07 08:08:52 +0200153 }
154#endif
155
Herbert Xu93efac32015-09-04 13:21:06 +0800156 if (x->props.mode != XFRM_MODE_TUNNEL)
157 goto skip_frag;
158
Hannes Frederic Sowa5a25cf12013-08-26 12:31:19 +0200159 if (skb->protocol == htons(ETH_P_IPV6))
160 mtu = ip6_skb_dst_mtu(skb);
161 else
162 mtu = dst_mtu(skb_dst(skb));
Steffen Klassertdd767852011-10-11 01:44:30 +0000163
Herbert Xu93efac32015-09-04 13:21:06 +0800164 toobig = skb->len > mtu && !skb_is_gso(skb);
165
166 if (toobig && xfrm6_local_dontfrag(skb)) {
Steffen Klassertdd767852011-10-11 01:44:30 +0000167 xfrm6_local_rxpmtu(skb, mtu);
168 return -EMSGSIZE;
Herbert Xu93efac32015-09-04 13:21:06 +0800169 } else if (!skb->ignore_df && toobig && skb->sk) {
Hannes Frederic Sowa628e3412013-08-14 13:05:23 +0200170 xfrm_local_error(skb, mtu);
Steffen Klassertdd767852011-10-11 01:44:30 +0000171 return -EMSGSIZE;
172 }
David Stevensad0081e2010-12-17 11:42:42 +0000173
Herbert Xu93efac32015-09-04 13:21:06 +0800174 if (toobig || dst_allfrag(skb_dst(skb)))
Eric W. Biederman7d8c6e32015-06-12 22:12:04 -0500175 return ip6_fragment(net, sk, skb,
176 __xfrm6_output_finish);
Herbert Xu93efac32015-09-04 13:21:06 +0800177
178skip_frag:
David Miller7026b1d2015-04-05 22:19:04 -0400179 return x->outer_mode->afinfo->output_finish(sk, skb);
David Stevensad0081e2010-12-17 11:42:42 +0000180}
181
Eric W. Biedermanede20592015-10-07 16:48:47 -0500182int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
Patrick McHardy16a66772006-01-06 23:01:48 -0800183{
Eric W. Biederman29a26a52015-09-15 20:04:16 -0500184 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
185 net, sk, skb, NULL, skb_dst(skb)->dev,
186 __xfrm6_output,
Steffen Klassert55967322014-04-07 08:08:52 +0200187 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
Patrick McHardy16a66772006-01-06 23:01:48 -0800188}