tcp: improve timestamp rtt accuracy

[vpp.git] / src / vnet / tcp / tcp_types.h

diff --git a/src/vnet/tcp/tcp_types.h b/src/vnet/tcp/tcp_types.h
index 3cf4e9e..d7bcac5 100644 (file)
--- a/src/vnet/tcp/tcp_types.h
+++ b/src/vnet/tcp/tcp_types.h
@@ -22,10 +22,14 @@
 #include <vnet/session/transport.h>
 #include <vppinfra/tw_timer_16t_2w_512sl.h>
 
-#define TCP_TICK 0.001                 /**< TCP tick period (s) */
-#define THZ (u32) (1/TCP_TICK)         /**< TCP tick frequency */
-#define TCP_TSTAMP_RESOLUTION TCP_TICK /**< Time stamp resolution */
-#define TCP_PAWS_IDLE 24 * 24 * 60 * 60 * THZ /**< 24 days */
+#define TCP_TICK 0.000001                      /**< TCP tick period (s) */
+#define THZ (u32) (1/TCP_TICK)                 /**< TCP tick frequency */
+
+#define TCP_TSTP_TICK 0.001                    /**< Timestamp tick (s) */
+#define TCP_TSTP_HZ (u32) (1/TCP_TSTP_TICK)    /**< Timestamp freq */
+#define TCP_PAWS_IDLE (24 * 86400 * TCP_TSTP_HZ)/**< 24 days */
+#define TCP_TSTP_TO_HZ (u32) (TCP_TSTP_TICK * THZ)
+
 #define TCP_FIB_RECHECK_PERIOD 1 * THZ /**< Recheck every 1s */
 #define TCP_MAX_OPTION_SPACE 40
 #define TCP_CC_DATA_SZ 24
@@ -355,7 +359,7 @@ typedef struct _tcp_connection
   /* RTT and RTO */
   u32 rto;             /**< Retransmission timeout */
   u32 rto_boff;                /**< Index for RTO backoff */
-  u32 srtt;            /**< Smoothed RTT */
+  u32 srtt;            /**< Smoothed RTT measured in @ref TCP_TICK */
   u32 rttvar;          /**< Smoothed mean RTT difference. Approximates variance */
   u32 rtt_seq;         /**< Sequence number for tracked ACK */
   f64 rtt_ts;          /**< Timestamp for tracked ACK */