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1/*
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>
5 *
6 * 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
12#include <linux/if_ether.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/skbuff.h>
16#include <linux/icmpv6.h>
17#include <linux/netfilter_ipv6.h>
18#include <net/dst.h>
19#include <net/ipv6.h>
20#include <net/ip6_route.h>
21#include <net/xfrm.h>
22
23int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
24 u8 **prevhdr)
25{
26 return ip6_find_1stfragopt(skb, prevhdr);
27}
28EXPORT_SYMBOL(xfrm6_find_1stfragopt);
29
30static int xfrm6_local_dontfrag(struct sk_buff *skb)
31{
32 int proto;
33 struct sock *sk = skb->sk;
34
35 if (sk) {
36 if (sk->sk_family != AF_INET6)
37 return 0;
38
39 proto = sk->sk_protocol;
40 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;
53 fl6.daddr = ipv6_hdr(skb)->daddr;
54
55 ipv6_local_rxpmtu(sk, &fl6, mtu);
56}
57
58void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
59{
60 struct flowi6 fl6;
61 const struct ipv6hdr *hdr;
62 struct sock *sk = skb->sk;
63
64 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
65 fl6.fl6_dport = inet_sk(sk)->inet_dport;
66 fl6.daddr = hdr->daddr;
67
68 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
69}
70
71static int xfrm6_tunnel_check_size(struct sk_buff *skb)
72{
73 int mtu, ret = 0;
74 struct dst_entry *dst = skb_dst(skb);
75
76 if (skb->ignore_df)
77 goto out;
78
79 mtu = dst_mtu(dst);
80 if (mtu < IPV6_MIN_MTU)
81 mtu = IPV6_MIN_MTU;
82
83 if ((!skb_is_gso(skb) && skb->len > mtu) ||
84 (skb_is_gso(skb) &&
85 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
86 skb->dev = dst->dev;
87 skb->protocol = htons(ETH_P_IPV6);
88
89 if (xfrm6_local_dontfrag(skb))
90 xfrm6_local_rxpmtu(skb, mtu);
91 else if (skb->sk)
92 xfrm_local_error(skb, mtu);
93 else
94 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
95 ret = -EMSGSIZE;
96 }
97out:
98 return ret;
99}
100
101int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
102{
103 int err;
104
105 err = xfrm6_tunnel_check_size(skb);
106 if (err)
107 return err;
108
109 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
110
111 return xfrm6_extract_header(skb);
112}
113
114int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
115{
116 int err;
117
118 err = xfrm_inner_extract_output(x, skb);
119 if (err)
120 return err;
121
122 skb->ignore_df = 1;
123 skb->protocol = htons(ETH_P_IPV6);
124
125 return x->outer_mode->output2(x, skb);
126}
127EXPORT_SYMBOL(xfrm6_prepare_output);
128
129int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
130{
131 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
132
133#ifdef CONFIG_NETFILTER
134 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
135#endif
136
137 return xfrm_output(sk, skb);
138}
139
140static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
141{
142 struct xfrm_state *x = skb_dst(skb)->xfrm;
143
144 return x->outer_mode->afinfo->output_finish(sk, skb);
145}
146
147static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
148{
149 struct dst_entry *dst = skb_dst(skb);
150 struct xfrm_state *x = dst->xfrm;
151 int mtu;
152 bool toobig;
153
154#ifdef CONFIG_NETFILTER
155 if (!x) {
156 IP6CB(skb)->flags |= IP6SKB_REROUTED;
157 return dst_output(net, sk, skb);
158 }
159#endif
160
161 if (x->props.mode != XFRM_MODE_TUNNEL)
162 goto skip_frag;
163
164 if (skb->protocol == htons(ETH_P_IPV6))
165 mtu = ip6_skb_dst_mtu(skb);
166 else
167 mtu = dst_mtu(skb_dst(skb));
168
169 toobig = skb->len > mtu && !skb_is_gso(skb);
170
171 if (toobig && xfrm6_local_dontfrag(skb)) {
172 xfrm6_local_rxpmtu(skb, mtu);
173 return -EMSGSIZE;
174 } else if (!skb->ignore_df && toobig && skb->sk) {
175 xfrm_local_error(skb, mtu);
176 return -EMSGSIZE;
177 }
178
179 if (toobig || dst_allfrag(skb_dst(skb)))
180 return ip6_fragment(net, sk, skb,
181 __xfrm6_output_finish);
182
183skip_frag:
184 return x->outer_mode->afinfo->output_finish(sk, skb);
185}
186
187int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
188{
189 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
190 net, sk, skb, NULL, skb_dst(skb)->dev,
191 __xfrm6_output,
192 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
193}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
4 * Copyright (C) 2002 USAGI/WIDE Project
5 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8#include <linux/if_ether.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/icmpv6.h>
13#include <linux/netfilter_ipv6.h>
14#include <net/dst.h>
15#include <net/ipv6.h>
16#include <net/ip6_route.h>
17#include <net/xfrm.h>
18
19int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
20 u8 **prevhdr)
21{
22 return ip6_find_1stfragopt(skb, prevhdr);
23}
24EXPORT_SYMBOL(xfrm6_find_1stfragopt);
25
26static int xfrm6_local_dontfrag(struct sk_buff *skb)
27{
28 int proto;
29 struct sock *sk = skb->sk;
30
31 if (sk) {
32 if (sk->sk_family != AF_INET6)
33 return 0;
34
35 proto = sk->sk_protocol;
36 if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
37 return inet6_sk(sk)->dontfrag;
38 }
39
40 return 0;
41}
42
43static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
44{
45 struct flowi6 fl6;
46 struct sock *sk = skb->sk;
47
48 fl6.flowi6_oif = sk->sk_bound_dev_if;
49 fl6.daddr = ipv6_hdr(skb)->daddr;
50
51 ipv6_local_rxpmtu(sk, &fl6, mtu);
52}
53
54void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
55{
56 struct flowi6 fl6;
57 const struct ipv6hdr *hdr;
58 struct sock *sk = skb->sk;
59
60 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
61 fl6.fl6_dport = inet_sk(sk)->inet_dport;
62 fl6.daddr = hdr->daddr;
63
64 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
65}
66
67static int xfrm6_tunnel_check_size(struct sk_buff *skb)
68{
69 int mtu, ret = 0;
70 struct dst_entry *dst = skb_dst(skb);
71
72 if (skb->ignore_df)
73 goto out;
74
75 mtu = dst_mtu(dst);
76 if (mtu < IPV6_MIN_MTU)
77 mtu = IPV6_MIN_MTU;
78
79 if ((!skb_is_gso(skb) && skb->len > mtu) ||
80 (skb_is_gso(skb) &&
81 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
82 skb->dev = dst->dev;
83 skb->protocol = htons(ETH_P_IPV6);
84
85 if (xfrm6_local_dontfrag(skb))
86 xfrm6_local_rxpmtu(skb, mtu);
87 else if (skb->sk)
88 xfrm_local_error(skb, mtu);
89 else
90 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
91 ret = -EMSGSIZE;
92 }
93out:
94 return ret;
95}
96
97int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
98{
99 int err;
100
101 err = xfrm6_tunnel_check_size(skb);
102 if (err)
103 return err;
104
105 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
106
107 return xfrm6_extract_header(skb);
108}
109
110int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
111{
112 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
113
114#ifdef CONFIG_NETFILTER
115 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
116#endif
117
118 return xfrm_output(sk, skb);
119}
120
121static int __xfrm6_output_state_finish(struct xfrm_state *x, struct sock *sk,
122 struct sk_buff *skb)
123{
124 const struct xfrm_state_afinfo *afinfo;
125 int ret = -EAFNOSUPPORT;
126
127 rcu_read_lock();
128 afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
129 if (likely(afinfo))
130 ret = afinfo->output_finish(sk, skb);
131 else
132 kfree_skb(skb);
133 rcu_read_unlock();
134
135 return ret;
136}
137
138static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
139{
140 struct xfrm_state *x = skb_dst(skb)->xfrm;
141
142 return __xfrm6_output_state_finish(x, sk, skb);
143}
144
145static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
146{
147 struct dst_entry *dst = skb_dst(skb);
148 struct xfrm_state *x = dst->xfrm;
149 int mtu;
150 bool toobig;
151
152#ifdef CONFIG_NETFILTER
153 if (!x) {
154 IP6CB(skb)->flags |= IP6SKB_REROUTED;
155 return dst_output(net, sk, skb);
156 }
157#endif
158
159 if (x->props.mode != XFRM_MODE_TUNNEL)
160 goto skip_frag;
161
162 if (skb->protocol == htons(ETH_P_IPV6))
163 mtu = ip6_skb_dst_mtu(skb);
164 else
165 mtu = dst_mtu(skb_dst(skb));
166
167 toobig = skb->len > mtu && !skb_is_gso(skb);
168
169 if (toobig && xfrm6_local_dontfrag(skb)) {
170 xfrm6_local_rxpmtu(skb, mtu);
171 kfree_skb(skb);
172 return -EMSGSIZE;
173 } else if (!skb->ignore_df && toobig && skb->sk) {
174 xfrm_local_error(skb, mtu);
175 kfree_skb(skb);
176 return -EMSGSIZE;
177 }
178
179 if (toobig || dst_allfrag(skb_dst(skb)))
180 return ip6_fragment(net, sk, skb,
181 __xfrm6_output_finish);
182
183skip_frag:
184 return __xfrm6_output_state_finish(x, sk, skb);
185}
186
187int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
188{
189 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
190 net, sk, skb, NULL, skb_dst(skb)->dev,
191 __xfrm6_output,
192 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
193}