1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 3ba8b074612f..a778ee024590 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -104,6 +104,7 @@ enum {
 #define TCP_MD5SIG              14      /* TCP MD5 Signature (RFC2385) */
 #define TCP_COOKIE_TRANSACTIONS 15      /* TCP Cookie Transactions */
 #define TCP_THIN_LINEAR_TIMEOUTS 16      /* Use linear timeouts for thin streams*/
+#define TCP_THIN_DUPACK         17      /* Fast retrans. after 1 dupack */
 
 /* for TCP_INFO socket option */
 #define TCPI_OPT_TIMESTAMPS     1
@@ -343,7 +344,8 @@ struct tcp_sock {
         u8      frto_counter;   /* Number of new acks after RTO */
         u8      nonagle     : 4,/* Disable Nagle algorithm?             */
                 thin_lto    : 1,/* Use linear timeouts for thin streams */
-                unused      : 3;
+                thin_dupack : 1,/* Fast retransmit on first dupack      */
+                unused      : 2;
 
 /* RTT measurement */
         u32     srtt;           /* smoothed round trip time << 3        */