ipv4: Create probe timer for tcp PMTU as per RFC4821

As per RFC4821 7.3.  Selecting Probe Size, a probe timer should
be armed once probing has converged. Once this timer expired,
probing again to take advantage of any path PMTU change. The
recommended probing interval is 10 minutes per RFC1981. Probing
interval could be sysctled by sysctl_tcp_probe_interval.

Eric Dumazet suggested to implement pseudo timer based on 32bits
jiffies tcp_time_stamp instead of using classic timer for such
rare event.

Signed-off-by: Fan Du <fan.du@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 5976bdecf58b..b9a6b0a94cc6 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -126,6 +126,8 @@ struct inet_connection_sock {
 
                 /* Information on the current probe. */
                 int               probe_size;
+
+                u32               probe_timestamp;
         } icsk_mtup;
         u32                       icsk_ca_priv[16];
         u32                       icsk_user_timeout;