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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 Klassertdd767852011-10-11 01:44:30 +000082
83 if (xfrm6_local_dontfrag(skb))
84 xfrm6_local_rxpmtu(skb, mtu);
85 else if (skb->sk)
Hannes Frederic Sowa628e3412013-08-14 13:05:23 +020086 xfrm_local_error(skb, mtu);
Steffen Klassertdd767852011-10-11 01:44:30 +000087 else
88 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 ret = -EMSGSIZE;
90 }
91
92 return ret;
93}
94
Herbert Xu36cf9ac2007-11-13 21:40:52 -080095int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070096{
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 int err;
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +090098
Herbert Xu36cf9ac2007-11-13 21:40:52 -080099 err = xfrm6_tunnel_check_size(skb);
100 if (err)
101 return err;
102
Herbert Xu60d5fcf2007-11-19 18:47:58 -0800103 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
104
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800105 return xfrm6_extract_header(skb);
106}
107
108int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
109{
110 int err;
111
Kazunori MIYAZAWAdf9dcb42008-03-24 14:51:51 -0700112 err = xfrm_inner_extract_output(x, skb);
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800113 if (err)
114 return err;
115
WANG Cong60ff7462014-05-04 16:39:18 -0700116 skb->ignore_df = 1;
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800117
118 return x->outer_mode->output2(x, skb);
119}
120EXPORT_SYMBOL(xfrm6_prepare_output);
121
Steffen Klassert43a4dea2011-05-09 19:36:38 +0000122int xfrm6_output_finish(struct sk_buff *skb)
Herbert Xu09b8f7a2006-06-22 03:08:03 -0700123{
Steffen Klassert55967322014-04-07 08:08:52 +0200124 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
125 skb->protocol = htons(ETH_P_IPV6);
126
Herbert Xu862b82c2007-11-13 21:43:11 -0800127#ifdef CONFIG_NETFILTER
128 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
129#endif
Herbert Xu09b8f7a2006-06-22 03:08:03 -0700130
Herbert Xu862b82c2007-11-13 21:43:11 -0800131 return xfrm_output(skb);
Herbert Xu09b8f7a2006-06-22 03:08:03 -0700132}
133
David Stevensad0081e2010-12-17 11:42:42 +0000134static int __xfrm6_output(struct sk_buff *skb)
135{
136 struct dst_entry *dst = skb_dst(skb);
137 struct xfrm_state *x = dst->xfrm;
Hannes Frederic Sowa5a25cf12013-08-26 12:31:19 +0200138 int mtu;
Hannes Frederic Sowa0ea9d5e2013-08-13 04:35:58 +0200139
Steffen Klassert55967322014-04-07 08:08:52 +0200140#ifdef CONFIG_NETFILTER
141 if (!x) {
142 IP6CB(skb)->flags |= IP6SKB_REROUTED;
143 return dst_output(skb);
144 }
145#endif
146
Hannes Frederic Sowa5a25cf12013-08-26 12:31:19 +0200147 if (skb->protocol == htons(ETH_P_IPV6))
148 mtu = ip6_skb_dst_mtu(skb);
149 else
150 mtu = dst_mtu(skb_dst(skb));
Steffen Klassertdd767852011-10-11 01:44:30 +0000151
152 if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
153 xfrm6_local_rxpmtu(skb, mtu);
154 return -EMSGSIZE;
WANG Cong60ff7462014-05-04 16:39:18 -0700155 } else if (!skb->ignore_df && skb->len > mtu && skb->sk) {
Hannes Frederic Sowa628e3412013-08-14 13:05:23 +0200156 xfrm_local_error(skb, mtu);
Steffen Klassertdd767852011-10-11 01:44:30 +0000157 return -EMSGSIZE;
158 }
David Stevensad0081e2010-12-17 11:42:42 +0000159
Dan Carpenter5b11b2e2012-01-31 21:45:26 +0000160 if (x->props.mode == XFRM_MODE_TUNNEL &&
Steffen Klassertdd767852011-10-11 01:44:30 +0000161 ((skb->len > mtu && !skb_is_gso(skb)) ||
David Stevensad0081e2010-12-17 11:42:42 +0000162 dst_allfrag(skb_dst(skb)))) {
Steffen Klassert43a4dea2011-05-09 19:36:38 +0000163 return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);
David Stevensad0081e2010-12-17 11:42:42 +0000164 }
Steffen Klassert43a4dea2011-05-09 19:36:38 +0000165 return x->outer_mode->afinfo->output_finish(skb);
David Stevensad0081e2010-12-17 11:42:42 +0000166}
167
Eric Dumazetaad88722014-04-15 13:47:15 -0400168int xfrm6_output(struct sock *sk, struct sk_buff *skb)
Patrick McHardy16a66772006-01-06 23:01:48 -0800169{
Steffen Klassert55967322014-04-07 08:08:52 +0200170 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb,
171 NULL, skb_dst(skb)->dev, __xfrm6_output,
172 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
Patrick McHardy16a66772006-01-06 23:01:48 -0800173}