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
xfrm6_local_rxpmtu(struct sk_buff * skb,u32 mtu)19 void 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
xfrm6_local_error(struct sk_buff * skb,u32 mtu)30 void 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
__xfrm6_output_finish(struct net * net,struct sock * sk,struct sk_buff * skb)43 static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
44 {
45 return xfrm_output(sk, skb);
46 }
47
__xfrm6_output(struct net * net,struct sock * sk,struct sk_buff * skb)48 static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
49 {
50 struct dst_entry *dst = skb_dst(skb);
51 struct xfrm_state *x = dst->xfrm;
52 unsigned int mtu;
53 bool toobig;
54
55 #ifdef CONFIG_NETFILTER
56 if (!x) {
57 IP6CB(skb)->flags |= IP6SKB_REROUTED;
58 return dst_output(net, sk, skb);
59 }
60 #endif
61
62 if (x->props.mode != XFRM_MODE_TUNNEL)
63 goto skip_frag;
64
65 if (skb->protocol == htons(ETH_P_IPV6))
66 mtu = ip6_skb_dst_mtu(skb);
67 else
68 mtu = dst_mtu(skb_dst(skb));
69
70 toobig = skb->len > mtu && !skb_is_gso(skb);
71
72 if (toobig && xfrm6_local_dontfrag(skb->sk)) {
73 xfrm6_local_rxpmtu(skb, mtu);
74 kfree_skb(skb);
75 return -EMSGSIZE;
76 } else if (!skb->ignore_df && toobig && skb->sk) {
77 xfrm_local_error(skb, mtu);
78 kfree_skb(skb);
79 return -EMSGSIZE;
80 }
81
82 if (toobig || dst_allfrag(skb_dst(skb)))
83 return ip6_fragment(net, sk, skb,
84 __xfrm6_output_finish);
85
86 skip_frag:
87 return xfrm_output(sk, skb);
88 }
89
xfrm6_output(struct net * net,struct sock * sk,struct sk_buff * skb)90 int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
91 {
92 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
93 net, sk, skb, skb->dev, skb_dst(skb)->dev,
94 __xfrm6_output,
95 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
96 }
97