1 // SPDX-License-Identifier: GPL-2.0-or-later
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>
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>
16 #include <net/ip6_route.h>
19 int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
22 return ip6_find_1stfragopt(skb, prevhdr);
24 EXPORT_SYMBOL(xfrm6_find_1stfragopt);
26 void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
29 struct sock *sk = skb->sk;
31 fl6.flowi6_oif = sk->sk_bound_dev_if;
32 fl6.daddr = ipv6_hdr(skb)->daddr;
34 ipv6_local_rxpmtu(sk, &fl6, mtu);
37 void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
40 const struct ipv6hdr *hdr;
41 struct sock *sk = skb->sk;
43 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
44 fl6.fl6_dport = inet_sk(sk)->inet_dport;
45 fl6.daddr = hdr->daddr;
47 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
50 static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
52 return xfrm_output(sk, skb);
55 static int xfrm6_noneed_fragment(struct sk_buff *skb)
58 u8 prevhdr = ipv6_hdr(skb)->nexthdr;
60 if (prevhdr != NEXTHDR_FRAGMENT)
62 fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr));
63 if (fh->nexthdr == NEXTHDR_ESP || fh->nexthdr == NEXTHDR_AUTH)
68 static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
70 struct dst_entry *dst = skb_dst(skb);
71 struct xfrm_state *x = dst->xfrm;
75 #ifdef CONFIG_NETFILTER
77 IP6CB(skb)->flags |= IP6SKB_REROUTED;
78 return dst_output(net, sk, skb);
82 if (x->props.mode != XFRM_MODE_TUNNEL)
85 if (skb->protocol == htons(ETH_P_IPV6))
86 mtu = ip6_skb_dst_mtu(skb);
88 mtu = dst_mtu(skb_dst(skb));
90 toobig = skb->len > mtu && !skb_is_gso(skb);
92 if (toobig && xfrm6_local_dontfrag(skb->sk)) {
93 xfrm6_local_rxpmtu(skb, mtu);
96 } else if (toobig && xfrm6_noneed_fragment(skb)) {
99 } else if (!skb->ignore_df && toobig && skb->sk) {
100 xfrm_local_error(skb, mtu);
105 if (toobig || dst_allfrag(skb_dst(skb)))
106 return ip6_fragment(net, sk, skb,
107 __xfrm6_output_finish);
110 return xfrm_output(sk, skb);
113 int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
115 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
116 net, sk, skb, skb->dev, skb_dst(skb)->dev,
118 !(IP6CB(skb)->flags & IP6SKB_REROUTED));