Document packet limiter and add quick reference for server-side

counterparts.

1 files changed, 17 insertions, 3 deletions

diff --git a/src/net/packetlimiter.cpp b/src/net/packetlimiter.cpp
index b99081714..92640bc99 100644
--- a/src/net/packetlimiter.cpp
+++ b/src/net/packetlimiter.cpp
@@ -33,13 +33,21 @@
 
 #include "debug.h"
 
+// Client-side packet limiter
+// The time limits here are all in units of 10ms (SDL timer tick).
+// See MILLISECONDS_IN_A_TICK.
+
 struct PacketLimit final
 {
     A_DEFAULT_COPY(PacketLimit)
 
+    // timer tick of the first packet in a burst
     int lastTime;
+    // number of basic ticks in one packet burst
     int timeLimit;
+    // number of packets inside an active packet burst
     int cnt;
+    // max number of packets allowed inside a packet burst
     int cntLimit;
 };
 
@@ -53,6 +61,13 @@ void PacketLimiter::initPacketLimiter()
     // here i setting packet limits. but current server is broken,
     // and this limits may not help.
 
+    // see also: server-side logic in:
+    // TMWA: src/map/clif.cpp (clif_check_packet_flood)
+    // Herc: src/map/clif.c (clif_parse)
+    //       src/common/socket.c (do_sockets(func_parse))
+    //         (herc has no per-packet limits, just a per-connection
+    //         fairness system.)
+
     mPacketLimits[CAST_SIZE(
         PacketType::PACKET_CHAT)].timeLimit = 10 + 5;
     mPacketLimits[CAST_SIZE(
@@ -268,10 +283,9 @@ bool PacketLimiter::checkPackets(const PacketTypeT type)
     const int cntLimit = limit.cntLimit;
 
     if (lastTime > tick_time)
-    {
+    { // integer wrap-around check
 //        instance()->mPacketLimits[type].lastTime = time;
 //        instance()->mPacketLimits[type].cnt = 0;
-
         return true;
     }
     else if (lastTime + timeLimit > time)
@@ -308,7 +322,7 @@ bool PacketLimiter::limitPackets(const PacketTypeT type)
     const int cntLimit = pack.cntLimit;
 
     if (lastTime > tick_time)
-    {
+    { // integer wrap-around check
         pack.lastTime = time;
         pack.cnt = 0;
         return true;