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Commit 0ea9d5e3 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by Steffen Klassert
Browse files

xfrm: introduce helper for safe determination of mtu 



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: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent 628e341f

include/net/route.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -317,4 +317,12 @@ static inline int ip4_dst_hoplimit(const struct dst_entry *dst) 
	return hoplimit;

	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 */
 
#endif	/* _ROUTE_H */

include/net/xfrm.h

+12 −0
Original line number Original line Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <net/route.h>

#include <net/route.h>

#include <net/ipv6.h>

#include <net/ipv6.h>

#include <net/ip6_fib.h>

#include <net/ip6_fib.h>

#include <net/ip6_route.h>

#include <net/flow.h>

#include <net/flow.h>





#include <linux/interrupt.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;

	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 */
 
#endif	/* _NET_XFRM_H */

net/ipv4/ip_output.c

+0 −8
Original line number Original line Diff line number Diff line
@@ -211,14 +211,6 @@ static inline int ip_finish_output2(struct sk_buff *skb) 
	return -EINVAL;

	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)

static int ip_finish_output(struct sk_buff *skb)

{

{

#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)

#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)

net/ipv4/xfrm4_output.c

+1 −3
Original line number Original line Diff line number Diff line
@@ -21,7 +21,6 @@ 
static int xfrm4_tunnel_check_size(struct sk_buff *skb)

static int xfrm4_tunnel_check_size(struct sk_buff *skb)

{

{

	int mtu, ret = 0;

	int mtu, ret = 0;

	struct dst_entry *dst;





	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)

	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)

		goto out;

		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)

	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df)

		goto out;

		goto out;





	dst = skb_dst(skb);

	mtu = xfrm_skb_dst_mtu(skb);

	mtu = dst_mtu(dst);

	if (skb->len > mtu) {

	if (skb->len > mtu) {

		if (skb->sk)

		if (skb->sk)

			xfrm_local_error(skb, mtu);

			xfrm_local_error(skb, mtu);

net/ipv6/xfrm6_output.c

+4 −1
Original line number Original line Diff line number Diff line
@@ -138,7 +138,10 @@ static int __xfrm6_output(struct sk_buff *skb) 
{

{

	struct dst_entry *dst = skb_dst(skb);

	struct dst_entry *dst = skb_dst(skb);

	struct xfrm_state *x = dst->xfrm;

	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)) {

	if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {

		xfrm6_local_rxpmtu(skb, mtu);

		xfrm6_local_rxpmtu(skb, mtu);