xfrm6_output.c
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/*
* 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>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#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>
int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
u8 **prevhdr)
{
return ip6_find_1stfragopt(skb, prevhdr);
}
EXPORT_SYMBOL(xfrm6_find_1stfragopt);
static int xfrm6_local_dontfrag(struct sk_buff *skb)
{
int proto;
struct sock *sk = skb->sk;
if (sk) {
if (sk->sk_family != AF_INET6)
return 0;
proto = sk->sk_protocol;
if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
return inet6_sk(sk)->dontfrag;
}
return 0;
}
static 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_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
struct dst_entry *dst = skb_dst(skb);
mtu = dst_mtu(dst);
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
if (!skb->ignore_df && skb->len > mtu) {
skb->dev = dst->dev;
skb->protocol = htons(ETH_P_IPV6);
if (xfrm6_local_dontfrag(skb))
xfrm6_local_rxpmtu(skb, mtu);
else if (skb->sk)
xfrm_local_error(skb, mtu);
else
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
ret = -EMSGSIZE;
}
return ret;
}
int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
err = xfrm6_tunnel_check_size(skb);
if (err)
return err;
XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
return xfrm6_extract_header(skb);
}
int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
err = xfrm_inner_extract_output(x, skb);
if (err)
return err;
skb->ignore_df = 1;
skb->protocol = htons(ETH_P_IPV6);
return x->outer_mode->output2(x, skb);
}
EXPORT_SYMBOL(xfrm6_prepare_output);
int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
{
memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
#ifdef CONFIG_NETFILTER
IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
#endif
return xfrm_output(sk, skb);
}
static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct xfrm_state *x = skb_dst(skb)->xfrm;
return x->outer_mode->afinfo->output_finish(sk, skb);
}
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;
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)) {
xfrm6_local_rxpmtu(skb, mtu);
return -EMSGSIZE;
} else if (!skb->ignore_df && toobig && skb->sk) {
xfrm_local_error(skb, mtu);
return -EMSGSIZE;
}
if (toobig || dst_allfrag(skb_dst(skb)))
return ip6_fragment(net, sk, skb,
__xfrm6_output_finish);
skip_frag:
return x->outer_mode->afinfo->output_finish(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, NULL, skb_dst(skb)->dev,
__xfrm6_output,
!(IP6CB(skb)->flags & IP6SKB_REROUTED));
}