[TCP]: MTU probing

Implementation of packetization layer path mtu discovery for TCP, based on
the internet-draft currently found at
<http://www.ietf.org/internet-drafts/draft-ietf-pmtud-method-05.txt>.

Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index fa587c94e9d..b3abe33f4e5 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -72,6 +72,7 @@ struct inet_connection_sock_af_ops {
  * @icsk_probes_out:       unanswered 0 window probes
  * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
  * @icsk_ack:              Delayed ACK control data
+ * @icsk_mtup;             MTU probing control data
  */
 struct inet_connection_sock {
         /* inet_sock has to be the first member! */
@@ -104,6 +105,18 @@ struct inet_connection_sock {
                 __u16             last_seg_size; /* Size of last incoming segment          */
                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */ 
         } icsk_ack;
+        struct {
+                int               enabled;
+
+                /* Range of MTUs to search */
+                int               search_high;
+                int               search_low;
+
+                /* Information on the current probe. */
+                int               probe_size;
+                __u32             probe_seq_start;
+                __u32             probe_seq_end;
+        } icsk_mtup;
         u32                       icsk_ca_priv[16];
 #define ICSK_CA_PRIV_SIZE       (16 * sizeof(u32))
 };