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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
19void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
20{
21 struct flowi6 fl6;
22 struct sock *sk = skb->sk;
23
24 fl6.flowi6_oif = sk->sk_bound_dev_if;
25 fl6.daddr = ipv6_hdr(skb)->daddr;
26
27 ipv6_local_rxpmtu(sk, &fl6, mtu);
28}
29
30void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
31{
32 struct flowi6 fl6;
33 const struct ipv6hdr *hdr;
34 struct sock *sk = skb->sk;
35
36 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
37 fl6.fl6_dport = inet_sk(sk)->inet_dport;
38 fl6.daddr = hdr->daddr;
39
40 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
41}
42
43static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
44{
45 return xfrm_output(sk, skb);
46}
47
48static int xfrm6_noneed_fragment(struct sk_buff *skb)
49{
50 struct frag_hdr *fh;
51 u8 prevhdr = ipv6_hdr(skb)->nexthdr;
52
53 if (prevhdr != NEXTHDR_FRAGMENT)
54 return 0;
55 fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr));
56 if (fh->nexthdr == NEXTHDR_ESP || fh->nexthdr == NEXTHDR_AUTH)
57 return 1;
58 return 0;
59}
60
61static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
62{
63 struct dst_entry *dst = skb_dst(skb);
64 struct xfrm_state *x = dst->xfrm;
65 unsigned int mtu;
66 bool toobig;
67
68#ifdef CONFIG_NETFILTER
69 if (!x) {
70 IP6CB(skb)->flags |= IP6SKB_REROUTED;
71 return dst_output(net, sk, skb);
72 }
73#endif
74
75 if (x->props.mode != XFRM_MODE_TUNNEL)
76 goto skip_frag;
77
78 if (skb->protocol == htons(ETH_P_IPV6))
79 mtu = ip6_skb_dst_mtu(skb);
80 else
81 mtu = dst_mtu(skb_dst(skb));
82
83 toobig = skb->len > mtu && !skb_is_gso(skb);
84
85 if (toobig && xfrm6_local_dontfrag(skb->sk)) {
86 xfrm6_local_rxpmtu(skb, mtu);
87 kfree_skb(skb);
88 return -EMSGSIZE;
89 } else if (toobig && xfrm6_noneed_fragment(skb)) {
90 skb->ignore_df = 1;
91 goto skip_frag;
92 } else if (!skb->ignore_df && toobig && skb->sk) {
93 xfrm_local_error(skb, mtu);
94 kfree_skb(skb);
95 return -EMSGSIZE;
96 }
97
98 if (toobig)
99 return ip6_fragment(net, sk, skb,
100 __xfrm6_output_finish);
101
102skip_frag:
103 return xfrm_output(sk, skb);
104}
105
106int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
107{
108 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
109 net, sk, skb, skb->dev, skb_dst(skb)->dev,
110 __xfrm6_output,
111 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
112}
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}
28
29EXPORT_SYMBOL(xfrm6_find_1stfragopt);
30
31static int xfrm6_local_dontfrag(struct sk_buff *skb)
32{
33 int proto;
34 struct sock *sk = skb->sk;
35
36 if (sk) {
37 proto = sk->sk_protocol;
38
39 if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
40 return inet6_sk(sk)->dontfrag;
41 }
42
43 return 0;
44}
45
46static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
47{
48 struct flowi6 fl6;
49 struct sock *sk = skb->sk;
50
51 fl6.flowi6_oif = sk->sk_bound_dev_if;
52 fl6.daddr = ipv6_hdr(skb)->daddr;
53
54 ipv6_local_rxpmtu(sk, &fl6, mtu);
55}
56
57static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
58{
59 struct flowi6 fl6;
60 struct sock *sk = skb->sk;
61
62 fl6.fl6_dport = inet_sk(sk)->inet_dport;
63 fl6.daddr = ipv6_hdr(skb)->daddr;
64
65 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
66}
67
68static int xfrm6_tunnel_check_size(struct sk_buff *skb)
69{
70 int mtu, ret = 0;
71 struct dst_entry *dst = skb_dst(skb);
72
73 mtu = dst_mtu(dst);
74 if (mtu < IPV6_MIN_MTU)
75 mtu = IPV6_MIN_MTU;
76
77 if (!skb->local_df && skb->len > mtu) {
78 skb->dev = dst->dev;
79
80 if (xfrm6_local_dontfrag(skb))
81 xfrm6_local_rxpmtu(skb, mtu);
82 else if (skb->sk)
83 xfrm6_local_error(skb, mtu);
84 else
85 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
86 ret = -EMSGSIZE;
87 }
88
89 return ret;
90}
91
92int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
93{
94 int err;
95
96 err = xfrm6_tunnel_check_size(skb);
97 if (err)
98 return err;
99
100 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
101
102 return xfrm6_extract_header(skb);
103}
104
105int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
106{
107 int err;
108
109 err = xfrm_inner_extract_output(x, skb);
110 if (err)
111 return err;
112
113 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
114#ifdef CONFIG_NETFILTER
115 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
116#endif
117
118 skb->protocol = htons(ETH_P_IPV6);
119 skb->local_df = 1;
120
121 return x->outer_mode->output2(x, skb);
122}
123EXPORT_SYMBOL(xfrm6_prepare_output);
124
125int xfrm6_output_finish(struct sk_buff *skb)
126{
127#ifdef CONFIG_NETFILTER
128 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
129#endif
130
131 skb->protocol = htons(ETH_P_IPV6);
132 return xfrm_output(skb);
133}
134
135static int __xfrm6_output(struct sk_buff *skb)
136{
137 struct dst_entry *dst = skb_dst(skb);
138 struct xfrm_state *x = dst->xfrm;
139 int mtu = ip6_skb_dst_mtu(skb);
140
141 if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
142 xfrm6_local_rxpmtu(skb, mtu);
143 return -EMSGSIZE;
144 } else if (!skb->local_df && skb->len > mtu && skb->sk) {
145 xfrm6_local_error(skb, mtu);
146 return -EMSGSIZE;
147 }
148
149 if (x->props.mode == XFRM_MODE_TUNNEL &&
150 ((skb->len > mtu && !skb_is_gso(skb)) ||
151 dst_allfrag(skb_dst(skb)))) {
152 return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);
153 }
154 return x->outer_mode->afinfo->output_finish(skb);
155}
156
157int xfrm6_output(struct sk_buff *skb)
158{
159 return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL,
160 skb_dst(skb)->dev, __xfrm6_output);
161}