Refactor timers

include/udx.h

@@ -216,6 +216,15 @@ struct udx_socket_s {
 #define UDX_CA_RECOVERY 2
 #define UDX_CA_LOSS     3
 
+typedef enum {
+  UDX_TIMER_NONE,
+  UDX_TIMER_RTO,
+  UDX_TIMER_RACK_REO,
+  UDX_TIMER_TLP,
+  UDX_TIMER_ZWP,
+  UDX_TIMER_KEEPALIVE
+} udx_stream_timer_type_t;
+
 struct udx_stream_s {
   uint32_t local_id; // must be first entry, so its compat with the cirbuf
   uint32_t remote_id;
@@ -293,6 +302,8 @@ struct udx_stream_s {
   uint32_t rate_interval_ms;       // saved rate sample: time elapsed
   bool rate_sample_is_app_limited; // saved rate sample: app limited?
 
+  udx_stream_timer_type_t pending_timer;
+  uint64_t next_rto_ts; // todo: remove this, calculate from oldest packet (head) in rtx queue
   uint32_t srtt;
   uint32_t rttvar;
   uint32_t rto;
@@ -360,12 +371,8 @@ struct udx_stream_s {
   bool tlp_permitted;   // if set, srtt has been updated since the last tlp
   uint32_t tlp_end_seq; // seq at time of tlp sent. invalid if tlp_inflight is not set
 
-  // optimize: use one timer and a action (RTO, RACK_REO, TLP) variable
-  int nrefs;
-  uv_timer_t rto_timer;
-  uv_timer_t rack_reo_timer;
-  uv_timer_t tlp_and_keepalive_timer;
-  uv_timer_t zwp_timer;
+  int nrefs;        // # of libuv handles open (2 timer, 1 prepare)
+  uv_timer_t timer; // RTO, RACK_REO,TLP, ZWP and keepalive timer. stream.pending_timer tells which is currently set (if any)
   uv_timer_t refill_pacing_timer;
 
   size_t inflight;