LXR linux/net/ipv6/xfrm6

   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_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
  86skip_frag:
  87        return xfrm_output(sk, skb);
  88}
  89
  90int 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