// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* xfrm6_output.c - Common IPsec encapsulation code for IPv6.
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* Copyright (C) 2002 USAGI/WIDE Project
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* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <linux/if_ether.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/icmpv6.h>
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#include <linux/netfilter_ipv6.h>
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#include <net/dst.h>
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#include <net/ipv6.h>
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#include <net/ip6_route.h>
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#include <net/xfrm.h>
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int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
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u8 **prevhdr)
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{
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return ip6_find_1stfragopt(skb, prevhdr);
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}
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EXPORT_SYMBOL(xfrm6_find_1stfragopt);
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void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
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{
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struct flowi6 fl6;
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struct sock *sk = skb->sk;
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fl6.flowi6_oif = sk->sk_bound_dev_if;
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fl6.daddr = ipv6_hdr(skb)->daddr;
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ipv6_local_rxpmtu(sk, &fl6, mtu);
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}
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void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
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{
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struct flowi6 fl6;
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const struct ipv6hdr *hdr;
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struct sock *sk = skb->sk;
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hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
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fl6.fl6_dport = inet_sk(sk)->inet_dport;
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fl6.daddr = hdr->daddr;
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ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
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}
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static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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return xfrm_output(sk, skb);
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}
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static int xfrm6_noneed_fragment(struct sk_buff *skb)
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{
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struct frag_hdr *fh;
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u8 prevhdr = ipv6_hdr(skb)->nexthdr;
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if (prevhdr != NEXTHDR_FRAGMENT)
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return 0;
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fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr));
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if (fh->nexthdr == NEXTHDR_ESP || fh->nexthdr == NEXTHDR_AUTH)
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return 1;
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return 0;
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}
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static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct dst_entry *dst = skb_dst(skb);
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struct xfrm_state *x = dst->xfrm;
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unsigned int mtu;
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bool toobig;
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#ifdef CONFIG_NETFILTER
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if (!x) {
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IP6CB(skb)->flags |= IP6SKB_REROUTED;
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return dst_output(net, sk, skb);
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}
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#endif
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if (x->props.mode != XFRM_MODE_TUNNEL)
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goto skip_frag;
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if (skb->protocol == htons(ETH_P_IPV6))
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mtu = ip6_skb_dst_mtu(skb);
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else
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mtu = dst_mtu(skb_dst(skb));
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toobig = skb->len > mtu && !skb_is_gso(skb);
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if (toobig && xfrm6_local_dontfrag(skb->sk)) {
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xfrm6_local_rxpmtu(skb, mtu);
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kfree_skb(skb);
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return -EMSGSIZE;
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} else if (toobig && xfrm6_noneed_fragment(skb)) {
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skb->ignore_df = 1;
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goto skip_frag;
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} else if (!skb->ignore_df && toobig && skb->sk) {
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xfrm_local_error(skb, mtu);
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kfree_skb(skb);
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return -EMSGSIZE;
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}
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if (toobig || dst_allfrag(skb_dst(skb)))
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return ip6_fragment(net, sk, skb,
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__xfrm6_output_finish);
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skip_frag:
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return xfrm_output(sk, skb);
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}
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int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
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net, sk, skb, skb->dev, skb_dst(skb)->dev,
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__xfrm6_output,
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!(IP6CB(skb)->flags & IP6SKB_REROUTED));
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}
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