Modules/IPStack - TCP RST for non-SYN packets to listening socket
[tpg/acess2.git] / KernelLand / Modules / IPStack / tcp.c
index 4ef4bb3..17f24f8 100644 (file)
@@ -26,6 +26,7 @@
 void   TCP_Initialise(void);
 void   TCP_StartConnection(tTCPConnection *Conn);
 void   TCP_SendPacket(tTCPConnection *Conn, tTCPHeader *Header, size_t DataLen, const void *Data);
+void   TCP_int_SendPacket(tInterface *Interface, const void *Dest, tTCPHeader *Header, size_t Length, const void *Data);
 void   TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer);
 void   TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Header, int Length);
 int    TCP_INT_AppendRecieved(tTCPConnection *Connection, const void *Data, size_t Length);
@@ -100,6 +101,11 @@ void TCP_Initialise(void)
  * \param Data Packet data (cast as a TCP Header)
  */
 void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, const void *Data )
+{
+       TCP_int_SendPacket(Conn->Interface, &Conn->RemoteIP, Header, Length, Data);
+}
+
+void TCP_int_SendPacket(tInterface *Interface, const void *Dest, tTCPHeader *Header, size_t Length, const void *Data )
 {
        tIPStackBuffer  *buffer;
        Uint16  checksum[3];
@@ -111,8 +117,8 @@ void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, co
        IPStack_Buffer_AppendSubBuffer(buffer, sizeof(*Header), 0, Header, NULL, NULL);
 
        LOG("Sending %i+%i to %s:%i", sizeof(*Header), Length,
-               IPStack_PrintAddress(Conn->Interface->Type, &Conn->RemoteIP),
-               Conn->RemotePort
+               IPStack_PrintAddress(Interface->Type, Dest),
+               ntohs(Header->RemotePort)
                );
 
        Header->Checksum = 0;
@@ -121,38 +127,59 @@ void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, co
        
        // TODO: Fragment packet
        
-       switch( Conn->Interface->Type )
+       switch( Interface->Type )
        {
        case 4:
                // Get IPv4 pseudo-header checksum
                {
                        Uint32  buf[3];
-                       buf[0] = ((tIPv4*)Conn->Interface->Address)->L;
-                       buf[1] = Conn->RemoteIP.v4.L;
-                       buf[2] = (htons(packlen)<<16) | (6<<8) | 0;
+                       buf[0] = ((tIPv4*)Interface->Address)->L;
+                       buf[1] = ((tIPv4*)Dest)->L;
+                       buf[2] = htonl( (packlen) | (IP4PROT_TCP<<16) | (0<<24) );
                        checksum[0] = htons( ~IPv4_Checksum(buf, sizeof(buf)) );        // Partial checksum
                }
                // - Combine checksums
                Header->Checksum = htons( IPv4_Checksum(checksum, sizeof(checksum)) );
-               IPv4_SendPacket(Conn->Interface, Conn->RemoteIP.v4, IP4PROT_TCP, 0, buffer);
+               IPv4_SendPacket(Interface, *(tIPv4*)Dest, IP4PROT_TCP, 0, buffer);
                break;
                
        case 6:
                // Append IPv6 Pseudo Header
                {
                        Uint32  buf[4+4+1+1];
-                       memcpy(buf, Conn->Interface->Address, 16);
-                       memcpy(&buf[4], &Conn->RemoteIP, 16);
+                       memcpy(buf, Interface->Address, 16);
+                       memcpy(&buf[4], Dest, 16);
                        buf[8] = htonl(packlen);
-                       buf[9] = htonl(6);
+                       buf[9] = htonl(IP4PROT_TCP);
                        checksum[0] = htons( ~IPv4_Checksum(buf, sizeof(buf)) );        // Partial checksum
                }
                Header->Checksum = htons( IPv4_Checksum(checksum, sizeof(checksum)) );  // Combine the two
-               IPv6_SendPacket(Conn->Interface, Conn->RemoteIP.v6, IP4PROT_TCP, Length, Data);
+               IPv6_SendPacket(Interface, *(tIPv6*)Dest, IP4PROT_TCP, buffer);
                break;
        }
 }
 
+void TCP_int_SendRSTTo(tInterface *Interface, void *Address, size_t Length, const tTCPHeader *Header)
+{
+       tTCPHeader      out_hdr = {0};
+       
+       out_hdr.DataOffset = (sizeof(out_hdr)/4) << 4;
+       out_hdr.DestPort = Header->SourcePort;
+       out_hdr.SourcePort = Header->DestPort;
+
+       size_t  data_len = Length - (Header->DataOffset>>4)*4;
+       out_hdr.AcknowlegementNumber = htonl( ntohl(Header->SequenceNumber) + data_len );
+       if( Header->Flags & TCP_FLAG_ACK ) {
+               out_hdr.Flags = TCP_FLAG_RST;
+               out_hdr.SequenceNumber = Header->AcknowlegementNumber;
+       }
+       else {
+               out_hdr.Flags = TCP_FLAG_RST|TCP_FLAG_ACK;
+               out_hdr.SequenceNumber = 0;
+       }
+       TCP_int_SendPacket(Interface, Address, &out_hdr, 0, NULL);
+}
+
 /**
  * \brief Handles a packet from the IP Layer
  * \param Interface    Interface the packet arrived from
@@ -163,8 +190,6 @@ void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, co
 void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer)
 {
        tTCPHeader      *hdr = Buffer;
-       tTCPListener    *srv;
-       tTCPConnection  *conn;
 
        #if TCP_DEBUG
        Log_Log("TCP", "TCP_GetPacket: <Local>:%i from [%s]:%i, Flags = %s%s%s%s%s%s%s%s",
@@ -195,7 +220,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
        }
 
        // Check Servers
-       for( srv = gTCP_Listeners; srv; srv = srv->Next )
+       for( tTCPListener *srv = gTCP_Listeners; srv; srv = srv->Next )
        {
                // Check if the server is active
                if(srv->Port == 0)      continue;
@@ -206,7 +231,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                
                Log_Log("TCP", "TCP_GetPacket: Matches server %p", srv);
                // Is this in an established connection?
-               for( conn = srv->Connections; conn; conn = conn->Next )
+               for( tTCPConnection *conn = srv->Connections; conn; conn = conn->Next )
                {
                        // Check that it is coming in on the same interface
                        if(conn->Interface != Interface)        continue;
@@ -231,16 +256,25 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                        return;
                }
 
-               Log_Log("TCP", "TCP_GetPacket: Opening Connection");
-               // Open a new connection (well, check that it's a SYN)
-               if(hdr->Flags != TCP_FLAG_SYN) {
-                       Log_Log("TCP", "TCP_GetPacket: Packet is not a SYN");
+               
+               if( hdr->Flags & TCP_FLAG_RST ) {
+                       LOG("RST, ignore");
+                       return ;
+               }
+               else if( hdr->Flags & TCP_FLAG_ACK ) {
+                       LOG("ACK, send RST");
+                       TCP_int_SendRSTTo(Interface, Address, Length, hdr);
                        return ;
                }
+               else if( !(hdr->Flags & TCP_FLAG_SYN) ) {
+                       LOG("Other, ignore");
+                       return ;
+               }
+               Log_Log("TCP", "TCP_GetPacket: Opening Connection");
                
                // TODO: Check for halfopen max
                
-               conn = TCP_int_CreateConnection(Interface, TCP_ST_SYN_RCVD);
+               tTCPConnection *conn = TCP_int_CreateConnection(Interface, TCP_ST_SYN_RCVD);
                conn->LocalPort = srv->Port;
                conn->RemotePort = ntohs(hdr->SourcePort);
                
@@ -248,6 +282,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                {
                case 4: conn->RemoteIP.v4 = *(tIPv4*)Address;   break;
                case 6: conn->RemoteIP.v6 = *(tIPv6*)Address;   break;
+               default:        ASSERTC(Interface->Type,==,4);  return;
                }
                
                conn->NextSequenceRcv = ntohl( hdr->SequenceNumber ) + 1;
@@ -288,7 +323,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 
        // Check Open Connections
        {
-               for( conn = gTCP_OutbountCons; conn; conn = conn->Next )
+               for( tTCPConnection *conn = gTCP_OutbountCons; conn; conn = conn->Next )
                {
                        // Check that it is coming in on the same interface
                        if(conn->Interface != Interface)        continue;
@@ -308,6 +343,11 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
        }
        
        Log_Log("TCP", "TCP_GetPacket: No Match");
+       // If not a RST, send a RST
+       if( !(hdr->Flags & TCP_FLAG_RST) )
+       {
+               TCP_int_SendRSTTo(Interface, Address, Length, hdr);
+       }
 }
 
 /**

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