IPStack/tcp - Added deferred ACK support

diff --git a/KernelLand/Modules/IPStack/tcp.c b/KernelLand/Modules/IPStack/tcp.c
index 71dd4e5..2bb90d1 100644 (file)
--- a/KernelLand/Modules/IPStack/tcp.c
+++ b/KernelLand/Modules/IPStack/tcp.c
@@ -18,7 +18,9 @@
 
 #define TCP_MAX_PACKET_SIZE    1024
 #define TCP_WINDOW_SIZE        0x2000
-#define TCP_RECIEVE_BUFFER_SIZE        0x4000
+#define TCP_RECIEVE_BUFFER_SIZE        0x8000
+#define TCP_DACK_THRESHOLD     4096
+#define TCP_DACK_TIMEOUT       500
 
 // === PROTOTYPES ===
 void   TCP_Initialise(void);
@@ -28,6 +30,7 @@ void  TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 void   TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Header, int Length);
 int    TCP_INT_AppendRecieved(tTCPConnection *Connection, const void *Data, size_t Length);
 void   TCP_INT_UpdateRecievedFromFuture(tTCPConnection *Connection);
+void   TCP_INT_SendACK(tTCPConnection *Connection);
 Uint16 TCP_GetUnusedPort();
  int   TCP_AllocatePort(Uint16 Port);
  int   TCP_DeallocatePort(Uint16 Port);
@@ -331,7 +334,10 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
        // Syncronise sequence values
        if(Header->Flags & TCP_FLAG_SYN) {
                // TODO: What if the packet also has data?
+               if( Connection->LastACKSequence != Connection->NextSequenceRcv )
+                       TCP_INT_SendACK(Connection);
                Connection->NextSequenceRcv = ntohl(Header->SequenceNumber);
+               Connection->LastACKSequence = Connection->NextSequenceRcv;
        }
        
        // Ackowledge a sent packet
@@ -343,6 +349,7 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
        // Get length of data
        dataLen = Length - (Header->DataOffset>>4)*4;
        LOG("dataLen = %i", dataLen);
+//     Log_Debug("TCP", "State %i, dataLen = %x", Connection->State, dataLen);
        
        // 
        // State Machine
@@ -448,6 +455,7 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
                                dataLen
                                );
                        if(rv != 0) {
+                               Log_Notice("TCP", "TCP_INT_AppendRecieved rv %i", rv);
                                break;
                        }
                        LOG("0x%08x += %i", Connection->NextSequenceRcv, dataLen);
@@ -458,19 +466,20 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
                        // all connections on the interface to lag.
                        // - Meh, no real issue, as the cache shouldn't be that large
                        TCP_INT_UpdateRecievedFromFuture(Connection);
-               
-                       // ACK Packet
-                       // TODO: Implement delayed ACK sending
-                       Header->DestPort = Header->SourcePort;
-                       Header->SourcePort = htons(Connection->LocalPort);
-                       Header->AcknowlegementNumber = htonl(Connection->NextSequenceRcv);
-                       Header->SequenceNumber = htonl(Connection->NextSequenceSend);
-                       Header->WindowSize = htons(TCP_WINDOW_SIZE);
-                       Header->Flags &= TCP_FLAG_SYN;  // Eliminate all flags save for SYN
-                       Header->Flags |= TCP_FLAG_ACK;  // Add ACK
-                       LOG("TCP", "Sending ACK for 0x%08x", Connection->NextSequenceRcv);
-                       TCP_SendPacket( Connection, Header, 0, NULL );
-                       //Connection->NextSequenceSend ++;
+
+                       #if 1
+                       // - Only send an ACK if we've had a burst
+                       if( Connection->NextSequenceRcv > (Uint32)(TCP_DACK_THRESHOLD + Connection->LastACKSequence) )
+                       {
+                               TCP_INT_SendACK(Connection);
+                               // - Extend TCP deferred ACK timer
+                               Time_RemoveTimer(Connection->DeferredACKTimer);
+                       }
+                       // - Schedule the deferred ACK timer (if already scheduled, this is a NOP)
+                       Time_ScheduleTimer(Connection->DeferredACKTimer, TCP_DACK_TIMEOUT);
+                       #else
+                       TCP_INT_SendACK(Connection);
+                       #endif
                }
                // Check if the packet is in window
                else if( WrapBetween(Connection->NextSequenceRcv, sequence_num,
@@ -541,7 +550,8 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
                {
                        Log_Log("TCP", "Fully out of sequence packet (0x%08x not between 0x%08x and 0x%08x), dropped",
                                sequence_num, Connection->NextSequenceRcv, Connection->NextSequenceRcv+TCP_WINDOW_SIZE);
-                       // TODO: Spec says we should send an empty ACK with the current state
+                       // Spec says we should send an empty ACK with the current state
+                       TCP_INT_SendACK(Connection);
                }
                break;
        
@@ -781,6 +791,25 @@ void TCP_INT_UpdateRecievedFromFuture(tTCPConnection *Connection)
        #endif
 }
 
+void TCP_INT_SendACK(tTCPConnection *Connection)
+{
+       tTCPHeader      hdr;
+       // ACK Packet
+       hdr.DataOffset = (sizeof(tTCPHeader)/4) << 4;
+       hdr.DestPort = htons(Connection->RemotePort);
+       hdr.SourcePort = htons(Connection->LocalPort);
+       hdr.AcknowlegementNumber = htonl(Connection->NextSequenceRcv);
+       hdr.SequenceNumber = htonl(Connection->NextSequenceSend);
+       hdr.WindowSize = htons(TCP_WINDOW_SIZE);
+       hdr.Flags = TCP_FLAG_ACK;       // TODO: Determine if SYN is wanted too
+       hdr.Checksum = 0;       // TODO: Checksum
+       hdr.UrgentPointer = 0;
+       Log_Debug("TCP", "Sending ACK for 0x%08x", Connection->NextSequenceRcv);
+       TCP_SendPacket( Connection, &hdr, 0, NULL );
+       //Connection->NextSequenceSend ++;
+       Connection->LastACKSequence = Connection->NextSequenceRcv;
+}
+
 /**
  * \fn Uint16 TCP_GetUnusedPort()
  * \brief Gets an unused port and allocates it
@@ -1060,6 +1089,8 @@ tVFS_Node *TCP_Client_Init(tInterface *Interface)
        conn->FuturePacketValidBytes = conn->FuturePacketData + TCP_WINDOW_SIZE;
        #endif
 
+       conn->DeferredACKTimer = Time_AllocateTimer( (void(*)(void*)) TCP_INT_SendACK, conn);
+
        SHORTLOCK(&glTCP_OutbountCons);
        conn->Next = gTCP_OutbountCons;
        gTCP_OutbountCons = conn;
@@ -1337,6 +1368,8 @@ void TCP_Client_Close(tVFS_Node *Node)
                break;
        }
        
+       Time_RemoveTimer(conn->DeferredACKTimer);
+       Time_FreeTimer(conn->DeferredACKTimer);
        free(conn);
        
        LEAVE('-');

diff --git a/KernelLand/Modules/IPStack/tcp.h b/KernelLand/Modules/IPStack/tcp.h
index 6aa404f..2247b90 100644 (file)
--- a/KernelLand/Modules/IPStack/tcp.h
+++ b/KernelLand/Modules/IPStack/tcp.h
@@ -7,6 +7,7 @@
 
 #include "ipstack.h"
 #include <adt.h>       // tRingBuffer
+#include <timers.h>    // tTimer
 
 typedef struct sTCPHeader      tTCPHeader;
 typedef struct sTCPListener    tTCPListener;
@@ -113,7 +114,11 @@ struct sTCPConnection
        
        Uint32  NextSequenceSend;       //!< Next sequence value for outbound packets
        Uint32  NextSequenceRcv;        //!< Next expected sequence value for inbound
-       
+
+       // Deferred ACK handling
+       Uint32  LastACKSequence;
+       tTimer  *DeferredACKTimer;      
+
        #if 0
        /**
         * \brief Non-ACKed packets