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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_tunnel_check_size(struct sk_buff *skb)
32{
33 int mtu, ret = 0;
34 struct dst_entry *dst = skb_dst(skb);
35
36 mtu = dst_mtu(dst);
37 if (mtu < IPV6_MIN_MTU)
38 mtu = IPV6_MIN_MTU;
39
40 if (!skb->local_df && skb->len > mtu) {
41 skb->dev = dst->dev;
42 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
43 ret = -EMSGSIZE;
44 }
45
46 return ret;
47}
48
49int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
50{
51 int err;
52
53 err = xfrm6_tunnel_check_size(skb);
54 if (err)
55 return err;
56
57 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
58
59 return xfrm6_extract_header(skb);
60}
61
62int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
63{
64 int err;
65
66 err = xfrm_inner_extract_output(x, skb);
67 if (err)
68 return err;
69
70 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
71#ifdef CONFIG_NETFILTER
72 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
73#endif
74
75 skb->protocol = htons(ETH_P_IPV6);
76 skb->local_df = 1;
77
78 return x->outer_mode->output2(x, skb);
79}
80EXPORT_SYMBOL(xfrm6_prepare_output);
81
82int xfrm6_output_finish(struct sk_buff *skb)
83{
84#ifdef CONFIG_NETFILTER
85 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
86#endif
87
88 skb->protocol = htons(ETH_P_IPV6);
89 return xfrm_output(skb);
90}
91
92static int __xfrm6_output(struct sk_buff *skb)
93{
94 struct dst_entry *dst = skb_dst(skb);
95 struct xfrm_state *x = dst->xfrm;
96
97 if ((x && x->props.mode == XFRM_MODE_TUNNEL) &&
98 ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
99 dst_allfrag(skb_dst(skb)))) {
100 return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);
101 }
102 return x->outer_mode->afinfo->output_finish(skb);
103}
104
105int xfrm6_output(struct sk_buff *skb)
106{
107 return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL,
108 skb_dst(skb)->dev, __xfrm6_output);
109}