LXR linux/net/ipv6/xfrm6

   1/*
   2 * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
   3 * Copyright (C) 2002 USAGI/WIDE Project
   4 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12#include <linux/if_ether.h>
  13#include <linux/kernel.h>
  14#include <linux/module.h>
  15#include <linux/skbuff.h>
  16#include <linux/icmpv6.h>
  17#include <linux/netfilter_ipv6.h>
  18#include <net/dst.h>
  19#include <net/ipv6.h>
  20#include <net/ip6_route.h>
  21#include <net/xfrm.h>
  22
  23int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
  24                          u8 **prevhdr)
  25{
  26        return ip6_find_1stfragopt(skb, prevhdr);
  27}
  28
  29EXPORT_SYMBOL(xfrm6_find_1stfragopt);
  30
  31static int xfrm6_local_dontfrag(struct sk_buff *skb)
  32{
  33        int proto;
  34        struct sock *sk = skb->sk;
  35
  36        if (sk) {
  37                if (sk->sk_family != AF_INET6)
  38                        return 0;
  39
  40                proto = sk->sk_protocol;
  41                if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
  42                        return inet6_sk(sk)->dontfrag;
  43        }
  44
  45        return 0;
  46}
  47
  48static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
  49{
  50        struct flowi6 fl6;
  51        struct sock *sk = skb->sk;
  52
  53        fl6.flowi6_oif = sk->sk_bound_dev_if;
  54        fl6.daddr = ipv6_hdr(skb)->daddr;
  55
  56        ipv6_local_rxpmtu(sk, &fl6, mtu);
  57}
  58
  59void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
  60{
  61        struct flowi6 fl6;
  62        const struct ipv6hdr *hdr;
  63        struct sock *sk = skb->sk;
  64
  65        hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
  66        fl6.fl6_dport = inet_sk(sk)->inet_dport;
  67        fl6.daddr = hdr->daddr;
  68
  69        ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
  70}
  71
  72static int xfrm6_tunnel_check_size(struct sk_buff *skb)
  73{
  74        int mtu, ret = 0;
  75        struct dst_entry *dst = skb_dst(skb);
  76
  77        mtu = dst_mtu(dst);
  78        if (mtu < IPV6_MIN_MTU)
  79                mtu = IPV6_MIN_MTU;
  80
  81        if (!skb->local_df && skb->len > mtu) {
  82                skb->dev = dst->dev;
  83
  84                if (xfrm6_local_dontfrag(skb))
  85                        xfrm6_local_rxpmtu(skb, mtu);
  86                else if (skb->sk)
  87                        xfrm_local_error(skb, mtu);
  88                else
  89                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
  90                ret = -EMSGSIZE;
  91        }
  92
  93        return ret;
  94}
  95
  96int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
  97{
  98        int err;
  99
 100        err = xfrm6_tunnel_check_size(skb);
 101        if (err)
 102                return err;
 103
 104        XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
 105
 106        return xfrm6_extract_header(skb);
 107}
 108
 109int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 110{
 111        int err;
 112
 113        err = xfrm_inner_extract_output(x, skb);
 114        if (err)
 115                return err;
 116
 117        memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 118#ifdef CONFIG_NETFILTER
 119        IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
 120#endif
 121
 122        skb->protocol = htons(ETH_P_IPV6);
 123        skb->local_df = 1;
 124
 125        return x->outer_mode->output2(x, skb);
 126}
 127EXPORT_SYMBOL(xfrm6_prepare_output);
 128
 129int xfrm6_output_finish(struct sk_buff *skb)
 130{
 131#ifdef CONFIG_NETFILTER
 132        IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
 133#endif
 134
 135        skb->protocol = htons(ETH_P_IPV6);
 136        return xfrm_output(skb);
 137}
 138
 139static int __xfrm6_output(struct sk_buff *skb)
 140{
 141        struct dst_entry *dst = skb_dst(skb);
 142        struct xfrm_state *x = dst->xfrm;
 143        int mtu;
 144
 145        if (skb->protocol == htons(ETH_P_IPV6))
 146                mtu = ip6_skb_dst_mtu(skb);
 147        else
 148                mtu = dst_mtu(skb_dst(skb));
 149
 150        if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
 151                xfrm6_local_rxpmtu(skb, mtu);
 152                return -EMSGSIZE;
 153        } else if (!skb->local_df && skb->len > mtu && skb->sk) {
 154                xfrm_local_error(skb, mtu);
 155                return -EMSGSIZE;
 156        }
 157
 158        if (x->props.mode == XFRM_MODE_TUNNEL &&
 159            ((skb->len > mtu && !skb_is_gso(skb)) ||
 160                dst_allfrag(skb_dst(skb)))) {
 161                        return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);
 162        }
 163        return x->outer_mode->afinfo->output_finish(skb);
 164}
 165
 166int xfrm6_output(struct sk_buff *skb)
 167{
 168        return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL,
 169                       skb_dst(skb)->dev, __xfrm6_output);
 170}
 171