Re: [PATCH net-next] sctp: Don't lookup dst if transport dst is still valid

[Vlad Yasevich <vyasevich@gmail.com>]

On 08/01/2013 10:45 PM, Fan Du wrote:
> When sctp sits on IPv6, sctp_transport_dst_check pass cookie as ZERO,
> as a result ip6_dst_check always fail out. This behaviour makes
> transport->dst useless, because every sctp_packet_transmit must look
> for valid dst.
>
> Add a dst_cookie into sctp_transport, and set the cookie whenever we
> get new dst for sctp_transport. So dst validness could be checked
> against it.
>
> Since I have split genid for IPv4 and IPv6, also delete/add IPv6 address
> will also bump IPv6 genid. So issues we discussed in:
> http://marc.info/?l=linux-netdev&m=137404469219410&w=4
> have all been sloved for this patch.
>
> Signed-off-by: Fan Du <fan.du@windriver.com>

Acked-by: Vlad Yasevich <vyasevich@gmail.com>

-vlad

> ---
>   include/net/sctp/sctp.h    |    2 +-
>   include/net/sctp/structs.h |    1 +
>   net/sctp/ipv6.c            |    2 +-
>   3 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
> index 554cf88..cb28df9 100644
> --- a/include/net/sctp/sctp.h
> +++ b/include/net/sctp/sctp.h
> @@ -613,7 +613,7 @@ static inline void sctp_v4_map_v6(union sctp_addr *addr)
>    */
>   static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
>   {
> -	if (t->dst && !dst_check(t->dst, 0)) {
> +	if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
>   		dst_release(t->dst);
>   		t->dst = NULL;
>   	}
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index 75c4c16..c0f4e29 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -946,6 +946,7 @@ struct sctp_transport {
>   	__u64 hb_nonce;
>
>   	struct rcu_head rcu;
> +	u32 dst_cookie;
>   };
>
>   struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index 85d688f..5a9402e 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -351,7 +351,7 @@ out:
>
>   		rt = (struct rt6_info *)dst;
>   		t->dst = dst;
> -
> +		t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
>   		pr_debug("rt6_dst:%pI6 rt6_src:%pI6\n", &rt->rt6i_dst.addr,
>   			 &fl6->saddr);
>   	} else {
>