Modules/IPStack - TCP RST for non-SYN packets to listening socket

diff --git a/KernelLand/Modules/IPStack/hwaddr_cache.c b/KernelLand/Modules/IPStack/hwaddr_cache.c
index 1a4f420..ab33e01 100644 (file)
--- a/KernelLand/Modules/IPStack/hwaddr_cache.c
+++ b/KernelLand/Modules/IPStack/hwaddr_cache.c
@@ -4,7 +4,7 @@
  * hwaddr_resolution.c
  * - Resolution/caching of hardware addresses
  */
-#define DEBUG  1
+#define DEBUG  0
 #include "ipstack.h"
 #include "icmp.h"
 #include "include/adapters_int.h"

diff --git a/KernelLand/Modules/IPStack/tcp.c b/KernelLand/Modules/IPStack/tcp.c
index 291f80b..17f24f8 100644 (file)
--- a/KernelLand/Modules/IPStack/tcp.c
+++ b/KernelLand/Modules/IPStack/tcp.c
@@ -135,7 +135,7 @@ void TCP_int_SendPacket(tInterface *Interface, const void *Dest, tTCPHeader *Hea
                        Uint32  buf[3];
                        buf[0] = ((tIPv4*)Interface->Address)->L;
                        buf[1] = ((tIPv4*)Dest)->L;
-                       buf[2] = (htons(packlen)<<16) | (6<<8) | 0;
+                       buf[2] = htonl( (packlen) | (IP4PROT_TCP<<16) | (0<<24) );
                        checksum[0] = htons( ~IPv4_Checksum(buf, sizeof(buf)) );        // Partial checksum
                }
                // - Combine checksums
@@ -150,7 +150,7 @@ void TCP_int_SendPacket(tInterface *Interface, const void *Dest, tTCPHeader *Hea
                        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
@@ -159,6 +159,27 @@ void TCP_int_SendPacket(tInterface *Interface, const void *Dest, tTCPHeader *Hea
        }
 }
 
+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
@@ -235,12 +256,21 @@ 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
                
@@ -252,6 +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;
@@ -315,23 +346,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
        // If not a RST, send a RST
        if( !(hdr->Flags & TCP_FLAG_RST) )
        {
-               tTCPHeader      out_hdr = {0};
-               
-               out_hdr.DataOffset = (sizeof(out_hdr)/4) << 4;
-               out_hdr.DestPort = hdr->SourcePort;
-               out_hdr.SourcePort = hdr->DestPort;
-       
-               size_t  data_len = Length - (hdr->DataOffset>>4)*4;
-               out_hdr.AcknowlegementNumber = htonl( ntohl(hdr->SequenceNumber) + data_len );
-               if( hdr->Flags & TCP_FLAG_ACK ) {
-                       out_hdr.Flags = TCP_FLAG_RST;
-                       out_hdr.SequenceNumber = hdr->AcknowlegementNumber;
-               }
-               else {
-                       out_hdr.Flags = TCP_FLAG_RST|TCP_FLAG_ACK;
-                       out_hdr.SequenceNumber = 0;
-               }
-               TCP_int_SendPacket(Interface, Address, &out_hdr, 0, NULL);
+               TCP_int_SendRSTTo(Interface, Address, Length, hdr);
        }
 }