[IPSEC]: Add XFRM_STATE_NOPMTUDISC flag

This patch adds the flag XFRM_STATE_NOPMTUDISC for xfrm states.  It is
similar to the nopmtudisc on IPIP/GRE tunnels.  It only has an effect
on IPv4 tunnel mode states.  For these states, it will ensure that the
DF flag is always cleared.

This is primarily useful to work around ICMP blackholes.

In future this flag could also allow a larger MTU to be set within the
tunnel just like IPIP/GRE tunnels.  This could be useful for short haul
tunnels where temporary fragmentation outside the tunnel is desired over
smaller fragments inside the tunnel.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: James Morris <jmorris@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2005-06-20 13:21:43 -07:00 committed by David S. Miller
parent d094cd83c0
commit dd87147eed
5 changed files with 21 additions and 2 deletions

View file

@ -196,6 +196,7 @@ struct xfrm_usersa_info {
__u8 flags;
#define XFRM_STATE_NOECN 1
#define XFRM_STATE_DECAP_DSCP 2
#define XFRM_STATE_NOPMTUDISC 4
};
struct xfrm_usersa_id {