drivers/net/npf/tcp_session.c

   1 /*
   2  * Copyright (c) 2001
   3  *      Politecnico di Torino.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the Politecnico
  13  * di Torino, and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #ifdef WIN32
  23 #include "tme.h"
  24 #include "tcp_session.h"
  25 #endif
  26
  27 #ifdef __FreeBSD
  28
  29 #ifdef _KERNEL
  30 #include <net/tme/tme.h>
  31 #include <net/tme/tcp_session.h>
  32 #else
  33 #include <tme/tme.h>
  34 #include <tme/tcp_session.h>
  35 #endif
  36
  37 #endif
  38
  39 uint32 tcp_session(uint8 *block, uint32 pkt_size, TME_DATA *data, MEM_TYPE *mem_ex, uint8 *mem_data)
  40
  41 {
  42
  43         uint32 next_status;
  44         uint32 direction=ULONG_AT(mem_data,12);
  45         uint8 flags=mem_ex->buffer[25];
  46         tcp_data *session=(tcp_data*)(block+data->key_len*4);
  47
  48         session->last_timestamp=session->timestamp_block;
  49         session->timestamp_block.tv_sec=0x7fffffff;
  50
  51         if (direction==session->direction)
  52         {
  53                 session->pkts_cln_to_srv++;
  54                 session->bytes_cln_to_srv+=pkt_size;
  55         }
  56         else
  57         {
  58                 session->pkts_srv_to_cln++;
  59                 session->bytes_srv_to_cln+=pkt_size;
  60         }
  61         /* we use only thes four flags, we don't need PSH or URG */
  62         flags&=(ACK|FIN|SYN|RST);
  63
  64         switch (session->status)
  65         {
  66         case ERROR_TCP:
  67                 next_status=ERROR_TCP;
  68                 break;
  69
  70         case UNKNOWN:
  71                 if (flags==SYN)
  72                 {
  73                         if (SW_ULONG_AT(mem_ex->buffer,20)!=0)
  74                         {
  75
  76                                 next_status=ERROR_TCP;
  77                                 break;
  78                         }
  79                         next_status=SYN_RCV;
  80                         session->syn_timestamp=session->last_timestamp;
  81
  82                         session->direction=direction;
  83                         session->seq_n_0_cln=SW_ULONG_AT(mem_ex->buffer,16);
  84                 }
  85                 else
  86                         next_status=UNKNOWN;
  87                 break;
  88
  89         case SYN_RCV:
  90                 if ((flags&RST)&&(direction!=session->direction))
  91                 {
  92                         next_status=CLOSED_RST;
  93                         break;
  94                 }
  95                 if ((flags==SYN)&&(direction==session->direction))
  96                 {       /* two syns... */
  97                         next_status=SYN_RCV;
  98                         session->seq_n_0_cln=SW_ULONG_AT(mem_ex->buffer,16);
  99                         break;
 100                 }
 101
 102                 if ((flags==(SYN|ACK))&&(direction!=session->direction))
 103                 {
 104                         if (SW_ULONG_AT(mem_ex->buffer,20)!=session->seq_n_0_cln+1)
 105                         {
 106                                 next_status=ERROR_TCP;
 107                                 break;
 108                         }
 109                         next_status=SYN_ACK_RCV;
 110
 111                         session->syn_ack_timestamp=session->last_timestamp;
 112
 113                         session->seq_n_0_srv=SW_ULONG_AT(mem_ex->buffer,16);
 114                         session->ack_cln=session->seq_n_0_cln+1;
 115                 }
 116                 else
 117                 {
 118                         next_status=ERROR_TCP;
 119                 }
 120                 break;
 121
 122         case SYN_ACK_RCV:
 123                 if ((flags&ACK)&&(flags&RST)&&(direction==session->direction))
 124                 {
 125                         next_status=CLOSED_RST;
 126                         session->ack_srv=SW_ULONG_AT(mem_ex->buffer,20);
 127                         break;
 128                 }
 129
 130                 if ((flags==ACK)&&(!(flags&(SYN|FIN|RST)))&&(direction==session->direction))
 131                 {
 132                         if (SW_ULONG_AT(mem_ex->buffer,20)!=session->seq_n_0_srv+1)
 133                         {
 134                                 next_status=ERROR_TCP;
 135                                 break;
 136                         }
 137                         next_status=ESTABLISHED;
 138                         session->ack_srv=session->seq_n_0_srv+1;
 139                         break;
 140                 }
 141                 if ((flags&ACK)&&(flags&SYN)&&(direction!=session->direction))
 142                 {
 143                         next_status=SYN_ACK_RCV;
 144                         break;
 145                 }
 146
 147                 next_status=ERROR_TCP;
 148                 break;
 149
 150         case ESTABLISHED:
 151                 if (flags&SYN)
 152                 {
 153                         if ((flags&ACK)&&
 154                                 (direction!=session->direction)&&
 155                                 ((session->ack_cln-SW_ULONG_AT(mem_ex->buffer,20))<MAX_WINDOW)
 156                                 )
 157                         {       /* SYN_ACK duplicato */
 158                                 next_status=ESTABLISHED;
 159                                 break;
 160                         }
 161
 162                         if ((!(flags&ACK))&&
 163                                 (direction==session->direction)&&
 164                                 (SW_ULONG_AT(mem_ex->buffer,16)==session->seq_n_0_cln)&&
 165                                 (ULONG_AT(mem_ex->buffer,20)==0)
 166                                 )
 167                         {       /* syn duplicato */
 168                                 next_status=ESTABLISHED;
 169                                 break;
 170                         }
 171
 172                         next_status=ERROR_TCP;
 173                         break;
 174                 }
 175                 if (flags&ACK)
 176                         if (direction==session->direction)
 177                         {
 178                                 uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
 179                                 if (new_ack-session->ack_srv<MAX_WINDOW)
 180                                         session->ack_srv=new_ack;
 181                         }
 182                         else
 183                         {
 184                                 uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
 185                                 if (new_ack-session->ack_cln<MAX_WINDOW)
 186                                         session->ack_cln=new_ack;
 187                         }
 188                 if (flags&RST)
 189                 {
 190                         next_status=CLOSED_RST;
 191                         break;
 192                 }
 193                 if (flags&FIN)
 194                         if (direction==session->direction)
 195                         {   /* an hack to make all things work */
 196                                 session->ack_cln=SW_ULONG_AT(mem_ex->buffer,16);
 197                                 next_status=FIN_CLN_RCV;
 198                                 break;
 199                         }
 200                         else
 201                         {
 202                                 session->ack_srv=SW_ULONG_AT(mem_ex->buffer,16);
 203                                 next_status=FIN_SRV_RCV;
 204                                 break;
 205                         }
 206                 next_status=ESTABLISHED;
 207                 break;
 208
 209         case CLOSED_RST:
 210                 next_status=CLOSED_RST;
 211                 break;
 212
 213         case FIN_SRV_RCV:
 214                 if (flags&SYN)
 215                 {
 216                         next_status=ERROR_TCP;
 217                         break;
 218                 }
 219
 220                 next_status=FIN_SRV_RCV;
 221
 222                 if (flags&ACK)
 223                 {
 224                         uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
 225                         if (direction!=session->direction)
 226                                 if ((new_ack-session->ack_cln)<MAX_WINDOW)
 227                                         session->ack_cln=new_ack;
 228                 }
 229
 230                 if (flags&RST)
 231                         next_status=CLOSED_RST;
 232                 else
 233                         if ((flags&FIN)&&(direction==session->direction))
 234                         {
 235                                 session->ack_cln=SW_ULONG_AT(mem_ex->buffer,16);
 236                                 next_status=CLOSED_FIN;
 237                         }
 238
 239                 break;
 240
 241         case FIN_CLN_RCV:
 242                 if (flags&SYN)
 243                 {
 244                         next_status=ERROR_TCP;
 245                         break;
 246                 }
 247
 248                 next_status=FIN_CLN_RCV;
 249
 250                 if (flags&ACK)
 251                 {
 252                         uint32 new_ack=SW_ULONG_AT(mem_ex->buffer,20);
 253                         if (direction==session->direction)
 254                                 if (new_ack-session->ack_srv<MAX_WINDOW)
 255                                         session->ack_srv=new_ack;
 256                 }
 257
 258                 if (flags&RST)
 259                         next_status=CLOSED_RST;
 260                 else
 261                         if ((flags&FIN)&&(direction!=session->direction))
 262                         {
 263                                 session->ack_srv=SW_ULONG_AT(mem_ex->buffer,16);
 264                                 next_status=CLOSED_FIN;
 265                         }
 266
 267                 break;
 268
 269         case CLOSED_FIN:
 270                         next_status=CLOSED_FIN;
 271                 break;
 272         default:
 273                 next_status=ERROR_TCP;
 274
 275         }
 276
 277         session->status=next_status;
 278
 279         if ((next_status==CLOSED_FIN)||(next_status==UNKNOWN)||(next_status==CLOSED_RST)||(next_status==ERROR_TCP))
 280                 session->timestamp_block=session->last_timestamp;
 281
 282         return TME_SUCCESS;
 283 }
 284