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xfrm: introduce helper for safe determination of mtu

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skb->sk socket can be of AF_INET or AF_INET6 address family. Thus we
always have to make sure we a referring to the correct interpretation
of skb->sk.

We only depend on header defines to query the mtu, so we don't introduce
a new dependency to ipv6 by this change.

Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Hannes Frederic Sowa 2013-08-13 04:35:58 +02:00 committed by Steffen Klassert
parent 628e341f31
commit 0ea9d5e3e0
5 changed files with 25 additions and 12 deletions
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8
include/net/route.h
View File

@ -317,4 +317,12 @@ static inline int ip4_dst_hoplimit(const struct dst_entry *dst)
return hoplimit;
}
static inline int ip_skb_dst_mtu(struct sk_buff *skb)
{
struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL;
return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ?
skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
}
#endif /* _ROUTE_H */

12
include/net/xfrm.h
View File

@ -20,6 +20,7 @@
#include <net/route.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#include <net/flow.h>
#include <linux/interrupt.h>
@ -1723,4 +1724,15 @@ static inline int xfrm_mark_put(struct sk_buff *skb, const struct xfrm_mark *m)
return ret;
}
static inline int xfrm_skb_dst_mtu(struct sk_buff *skb)
{
struct sock *sk = skb->sk;
if (sk && sk->sk_family == AF_INET6)
return ip6_skb_dst_mtu(skb);
else if (sk && sk->sk_family == AF_INET)
return ip_skb_dst_mtu(skb);
return dst_mtu(skb_dst(skb));
}
#endif /* _NET_XFRM_H */

8
net/ipv4/ip_output.c
View File

@ -211,14 +211,6 @@ static inline int ip_finish_output2(struct sk_buff *skb)
return -EINVAL;
}
static inline int ip_skb_dst_mtu(struct sk_buff *skb)
{
struct inet_sock *inet = skb->sk ? inet_sk(skb->sk) : NULL;
return (inet && inet->pmtudisc == IP_PMTUDISC_PROBE) ?
skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
}
static int ip_finish_output(struct sk_buff *skb)
{
#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)

4
net/ipv4/xfrm4_output.c
View File

@ -21,7 +21,6 @@
static int xfrm4_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
struct dst_entry *dst;
if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
goto out;
@ -29,8 +28,7 @@ static int xfrm4_tunnel_check_size(struct sk_buff *skb)
if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df)
goto out;
dst = skb_dst(skb);
mtu = dst_mtu(dst);
mtu = xfrm_skb_dst_mtu(skb);
if (skb->len > mtu) {
if (skb->sk)
xfrm_local_error(skb, mtu);

5
net/ipv6/xfrm6_output.c
View File

@ -138,7 +138,10 @@ static int __xfrm6_output(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct xfrm_state *x = dst->xfrm;
int mtu = ip6_skb_dst_mtu(skb);
int mtu = xfrm_skb_dst_mtu(skb);
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
xfrm6_local_rxpmtu(skb, mtu);