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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* xfrm6_output.c - Common IPsec encapsulation code for IPv6.
* Copyright (C) 2002 USAGI/WIDE Project
* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmpv6.h>
#include <linux/netfilter_ipv6.h>
#include <net/dst.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/xfrm.h>
void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
{
struct flowi6 fl6;
struct sock *sk = skb->sk;
fl6.flowi6_oif = sk->sk_bound_dev_if;
fl6.daddr = ipv6_hdr(skb)->daddr;
ipv6_local_rxpmtu(sk, &fl6, mtu);
}
void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
{
struct flowi6 fl6;
const struct ipv6hdr *hdr;
struct sock *sk = skb->sk;
hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
fl6.fl6_dport = inet_sk(sk)->inet_dport;
fl6.daddr = hdr->daddr;
ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
}
static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
return xfrm_output(sk, skb);
}
static int xfrm6_noneed_fragment(struct sk_buff *skb)
{
struct frag_hdr *fh;
u8 prevhdr = ipv6_hdr(skb)->nexthdr;
if (prevhdr != NEXTHDR_FRAGMENT)
return 0;
fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr));
if (fh->nexthdr == NEXTHDR_ESP || fh->nexthdr == NEXTHDR_AUTH)
return 1;
return 0;
}
static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct xfrm_state *x = dst->xfrm;
unsigned int mtu;
bool toobig;
#ifdef CONFIG_NETFILTER
if (!x) {
IP6CB(skb)->flags |= IP6SKB_REROUTED;
return dst_output(net, sk, skb);
}
#endif
if (x->props.mode != XFRM_MODE_TUNNEL)
goto skip_frag;
if (skb->protocol == htons(ETH_P_IPV6))
mtu = ip6_skb_dst_mtu(skb);
else
mtu = dst_mtu(skb_dst(skb));
toobig = skb->len > mtu && !skb_is_gso(skb);
if (toobig && xfrm6_local_dontfrag(skb->sk)) {
xfrm6_local_rxpmtu(skb, mtu);
kfree_skb(skb);
return -EMSGSIZE;
} else if (toobig && xfrm6_noneed_fragment(skb)) {
skb->ignore_df = 1;
goto skip_frag;
} else if (!skb->ignore_df && toobig && skb->sk) {
xfrm_local_error(skb, mtu);
kfree_skb(skb);
return -EMSGSIZE;
}
if (toobig || dst_allfrag(skb_dst(skb)))
return ip6_fragment(net, sk, skb,
__xfrm6_output_finish);
skip_frag:
return xfrm_output(sk, skb);
}
int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
net, sk, skb, skb->dev, skb_dst(skb)->dev,
__xfrm6_output,
!(IP6CB(skb)->flags & IP6SKB_REROUTED));
}
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