From 779fe3d42bb1095970b164804e4269cfe776fc58 Mon Sep 17 00:00:00 2001
From: Vivek Jain <jain.vivek.anand@gmail.com>
Date: Sat, 19 Jun 2021 03:45:27 +0000
Subject: [PATCH] tcp: trace BBR mode using literal array

---
 src/internet/model/tcp-bbr.cc | 26 +++++++-------------------
 src/internet/model/tcp-bbr.h  | 11 +++++------
 2 files changed, 12 insertions(+), 25 deletions(-)

diff --git a/src/internet/model/tcp-bbr.cc b/src/internet/model/tcp-bbr.cc
index 6cb5339ae..86cba43ac 100644
--- a/src/internet/model/tcp-bbr.cc
+++ b/src/internet/model/tcp-bbr.cc
@@ -130,6 +130,12 @@ TcpBbr::TcpBbr (const TcpBbr &sock)
   NS_LOG_FUNCTION (this);
 }
 
+const char* const
+TcpBbr::BbrModeName[BBR_PROBE_RTT + 1] =
+{
+  "BBR_STARTUP", "BBR_DRAIN", "BBR_PROBE_BW", "BBR_PROBE_RTT"
+};
+
 void
 TcpBbr::SetStream (uint32_t stream)
 {
@@ -637,29 +643,11 @@ TcpBbr::UpdateControlParameters (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpR
   SetCwnd (tcb, rs);
 }
 
-std::string
-TcpBbr::WhichState (BbrMode_t mode) const
-{
-  switch (mode)
-    {
-    case 0:
-      return "BBR_STARTUP";
-    case 1:
-      return "BBR_DRAIN";
-    case 2:
-      return "BBR_PROBE_BW";
-    case 3:
-      return "BBR_PROBE_RTT";
-    }
-  NS_ASSERT (false);
-  return "";
-}
-
 void
 TcpBbr::SetBbrState (BbrMode_t mode)
 {
   NS_LOG_FUNCTION (this << mode);
-  NS_LOG_DEBUG (Simulator::Now () << " Changing from " << WhichState (m_state) << " to " << WhichState (mode));
+  NS_LOG_DEBUG (Simulator::Now () << " Changing from " << BbrModeName[m_state] << " to " << BbrModeName[mode]);
   m_state = mode;
 }
 
diff --git a/src/internet/model/tcp-bbr.h b/src/internet/model/tcp-bbr.h
index 61a1dea48..fee091312 100644
--- a/src/internet/model/tcp-bbr.h
+++ b/src/internet/model/tcp-bbr.h
@@ -78,6 +78,11 @@ public:
                          uint32_t>
   MaxBandwidthFilter_t;
 
+  /**
+   * \brief Literal names of BBR mode for use in log messages
+   */
+  static const char* const BbrModeName[BBR_PROBE_RTT + 1];
+
   /**
    * Assign a fixed random variable stream number to the random variables
    * used by this model.
@@ -316,12 +321,6 @@ protected:
    */
   void SetBbrState (BbrMode_t state);
 
-  /**
-   * \brief Maps mode into string.
-   * \return string translation of mode value.
-   */
-  std::string WhichState (BbrMode_t state) const;
-
   /**
   * \brief Find Cwnd increment based on ack aggregation.
   * \return uint32_t aggregate cwnd.