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Commit dd767856 authored by Steffen Klassert's avatar Steffen Klassert Committed by David S. Miller
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xfrm6: Don't call icmpv6_send on local error 



Calling icmpv6_send() on a local message size error leads to
an incorrect update of the path mtu. So use xfrm6_local_rxpmtu()
to notify about the pmtu if the IPV6_DONTFRAG socket option is
set on an udp or raw socket, according RFC 3542 and use
ipv6_local_error() otherwise.

Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 299b0767

net/ipv6/xfrm6_output.c

+54 −2
Original line number Diff line number Diff line
@@ -28,6 +28,43 @@ int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb, 


EXPORT_SYMBOL(xfrm6_find_1stfragopt);



static int xfrm6_local_dontfrag(struct sk_buff *skb)

{

	int proto;

	struct sock *sk = skb->sk;



	if (sk) {

		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;

	ipv6_addr_copy(&fl6.daddr, &ipv6_hdr(skb)->daddr);



	ipv6_local_rxpmtu(sk, &fl6, mtu);

}



static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)

{

	struct flowi6 fl6;

	struct sock *sk = skb->sk;



	fl6.fl6_dport = inet_sk(sk)->inet_dport;

	ipv6_addr_copy(&fl6.daddr, &ipv6_hdr(skb)->daddr);



	ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);

}



static int xfrm6_tunnel_check_size(struct sk_buff *skb)

{

	int mtu, ret = 0;
@@ -39,6 +76,12 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb) 


	if (!skb->local_df && skb->len > mtu) {

		skb->dev = dst->dev;



		if (xfrm6_local_dontfrag(skb))

			xfrm6_local_rxpmtu(skb, mtu);

		else if (skb->sk)

			xfrm6_local_error(skb, mtu);

		else

			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

		ret = -EMSGSIZE;

	}
@@ -93,9 +136,18 @@ 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);



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

		xfrm6_local_rxpmtu(skb, mtu);

		return -EMSGSIZE;

	} else if (!skb->local_df && skb->len > mtu && skb->sk) {

		xfrm6_local_error(skb, mtu);

		return -EMSGSIZE;

	}



	if ((x && x->props.mode == XFRM_MODE_TUNNEL) &&

	    ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||

	    ((skb->len > mtu && !skb_is_gso(skb)) ||

		dst_allfrag(skb_dst(skb)))) {

			return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);

	}