epan/dfilter/gencode.c

   1 /*
   2  * $Id: gencode.c,v 1.10 2003/06/13 10:03:25 guy Exp $
   3  *
   4  * Ethereal - Network traffic analyzer
   5  * By Gerald Combs <gerald@ethereal.com>
   6  * Copyright 2001 Gerald Combs
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21  */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include "dfilter-int.h"
  28 #include "dfvm.h"
  29 #include "syntax-tree.h"
  30 #include "sttype-range.h"
  31 #include "sttype-test.h"
  32 #include "ftypes/ftypes.h"
  33 #include <epan/gdebug.h>
  34
  35 static void
  36 gencode(dfwork_t *dfw, stnode_t *st_node);
  37
  38 static void
  39 dfw_append_insn(dfwork_t *dfw, dfvm_insn_t *insn)
  40 {
  41         insn->id = dfw->next_insn_id;
  42         dfw->next_insn_id++;
  43         g_ptr_array_add(dfw->insns, insn);
  44 }
  45
  46 /* returns register number */
  47 static int
  48 dfw_append_read_tree(dfwork_t *dfw, header_field_info *hfinfo)
  49 {
  50         dfvm_insn_t     *insn;
  51         dfvm_value_t    *val1, *val2;
  52         int             reg = -1;
  53         gboolean        added_new_hfinfo = FALSE;
  54
  55         /* Rewind to find the first field of this name. */
  56         while (hfinfo->same_name_prev) {
  57                 hfinfo = hfinfo->same_name_prev;
  58         }
  59
  60         /* Keep track of which registers
  61          * were used for which hfinfo's so that we
  62          * can re-use registers. */
  63         reg = GPOINTER_TO_UINT(
  64                         g_hash_table_lookup(dfw->loaded_fields, hfinfo));
  65         if (reg) {
  66                 /* Reg's are stored in has as reg+1, so
  67                  * that the non-existence of a hfinfo in
  68                  * the hash, or 0, can be differentiated from
  69                  * a hfinfo being loaded into register #0. */
  70                 reg--;
  71         }
  72         else {
  73                 reg = dfw->next_register++;
  74                 g_hash_table_insert(dfw->loaded_fields,
  75                         hfinfo, GUINT_TO_POINTER(reg + 1));
  76
  77                 added_new_hfinfo = TRUE;
  78         }
  79
  80         insn = dfvm_insn_new(READ_TREE);
  81         val1 = dfvm_value_new(HFINFO);
  82         val1->value.hfinfo = hfinfo;
  83         val2 = dfvm_value_new(REGISTER);
  84         val2->value.numeric = reg;
  85
  86         insn->arg1 = val1;
  87         insn->arg2 = val2;
  88         dfw_append_insn(dfw, insn);
  89
  90         if (added_new_hfinfo) {
  91                 while (hfinfo) {
  92                         /* Record the FIELD_ID in hash of interesting fields. */
  93                         g_hash_table_insert(dfw->interesting_fields,
  94                             GINT_TO_POINTER(hfinfo->id),
  95                             GUINT_TO_POINTER(TRUE));
  96                         hfinfo = hfinfo->same_name_next;
  97                 }
  98         }
  99
 100         return reg;
 101 }
 102
 103 /* returns register number */
 104 static int
 105 dfw_append_put_fvalue(dfwork_t *dfw, fvalue_t *fv)
 106 {
 107         dfvm_insn_t     *insn;
 108         dfvm_value_t    *val1, *val2;
 109         int             reg;
 110
 111         insn = dfvm_insn_new(PUT_FVALUE);
 112         val1 = dfvm_value_new(FVALUE);
 113         val1->value.fvalue = fv;
 114         val2 = dfvm_value_new(REGISTER);
 115         reg = dfw->next_register++;
 116         val2->value.numeric = reg;
 117         insn->arg1 = val1;
 118         insn->arg2 = val2;
 119         dfw_append_insn(dfw, insn);
 120
 121         return reg;
 122 }
 123
 124 /* returns register number */
 125 static int
 126 dfw_append_mk_range(dfwork_t *dfw, stnode_t *node)
 127 {
 128         int                     hf_reg, reg;
 129         header_field_info       *hfinfo;
 130         dfvm_insn_t             *insn;
 131         dfvm_value_t            *val;
 132
 133         hfinfo = sttype_range_hfinfo(node);
 134         hf_reg = dfw_append_read_tree(dfw, hfinfo);
 135
 136         insn = dfvm_insn_new(MK_RANGE);
 137
 138         val = dfvm_value_new(REGISTER);
 139         val->value.numeric = hf_reg;
 140         insn->arg1 = val;
 141
 142         val = dfvm_value_new(REGISTER);
 143         reg =dfw->next_register++;
 144         val->value.numeric = reg;
 145         insn->arg2 = val;
 146
 147         val = dfvm_value_new(DRANGE);
 148         val->value.drange = sttype_range_drange(node);
 149         insn->arg3 = val;
 150
 151         sttype_range_remove_drange(node);
 152
 153         dfw_append_insn(dfw, insn);
 154
 155         return reg;
 156 }
 157
 158
 159 static void
 160 gen_relation(dfwork_t *dfw, dfvm_opcode_t op, stnode_t *st_arg1, stnode_t *st_arg2)
 161 {
 162         sttype_id_t     type1, type2;
 163         dfvm_insn_t     *insn;
 164         dfvm_value_t    *val1, *val2;
 165         dfvm_value_t    *jmp1 = NULL, *jmp2 = NULL;
 166         int             reg1 = -1, reg2 = -1;
 167         header_field_info       *hfinfo;
 168
 169         type1 = stnode_type_id(st_arg1);
 170         type2 = stnode_type_id(st_arg2);
 171
 172         if (type1 == STTYPE_FIELD) {
 173                 hfinfo = stnode_data(st_arg1);
 174                 reg1 = dfw_append_read_tree(dfw, hfinfo);
 175
 176                 insn = dfvm_insn_new(IF_FALSE_GOTO);
 177                 jmp1 = dfvm_value_new(INSN_NUMBER);
 178                 insn->arg1 = jmp1;
 179                 dfw_append_insn(dfw, insn);
 180         }
 181         else if (type1 == STTYPE_FVALUE) {
 182                 reg1 = dfw_append_put_fvalue(dfw, stnode_data(st_arg1));
 183         }
 184         else if (type1 == STTYPE_RANGE) {
 185                 reg1 = dfw_append_mk_range(dfw, st_arg1);
 186         }
 187         else {
 188                 g_assert_not_reached();
 189         }
 190
 191         if (type2 == STTYPE_FIELD) {
 192                 hfinfo = stnode_data(st_arg2);
 193                 reg2 = dfw_append_read_tree(dfw, hfinfo);
 194
 195                 insn = dfvm_insn_new(IF_FALSE_GOTO);
 196                 jmp2 = dfvm_value_new(INSN_NUMBER);
 197                 insn->arg1 = jmp2;
 198                 dfw_append_insn(dfw, insn);
 199         }
 200         else if (type2 == STTYPE_FVALUE) {
 201                 reg2 = dfw_append_put_fvalue(dfw, stnode_data(st_arg2));
 202         }
 203         else if (type2 == STTYPE_RANGE) {
 204                 reg2 = dfw_append_mk_range(dfw, st_arg2);
 205         }
 206         else {
 207                 g_assert_not_reached();
 208         }
 209
 210         insn = dfvm_insn_new(op);
 211         val1 = dfvm_value_new(REGISTER);
 212         val1->value.numeric = reg1;
 213         val2 = dfvm_value_new(REGISTER);
 214         val2->value.numeric = reg2;
 215         insn->arg1 = val1;
 216         insn->arg2 = val2;
 217         dfw_append_insn(dfw, insn);
 218
 219         if (jmp1) {
 220                 jmp1->value.numeric = dfw->next_insn_id;
 221         }
 222
 223         if (jmp2) {
 224                 jmp2->value.numeric = dfw->next_insn_id;
 225         }
 226 }
 227
 228
 229 static void
 230 gen_test(dfwork_t *dfw, stnode_t *st_node)
 231 {
 232         test_op_t       st_op;
 233         stnode_t        *st_arg1, *st_arg2;
 234         dfvm_value_t    *val1;
 235         dfvm_insn_t     *insn;
 236
 237         header_field_info       *hfinfo;
 238
 239         sttype_test_get(st_node, &st_op, &st_arg1, &st_arg2);
 240
 241         switch (st_op) {
 242                 case TEST_OP_UNINITIALIZED:
 243                         g_assert_not_reached();
 244                         break;
 245
 246                 case TEST_OP_EXISTS:
 247                         val1 = dfvm_value_new(HFINFO);
 248                         hfinfo = stnode_data(st_arg1);
 249
 250                         /* Rewind to find the first field of this name. */
 251                         while (hfinfo->same_name_prev) {
 252                                 hfinfo = hfinfo->same_name_prev;
 253                         }
 254                         val1->value.hfinfo = hfinfo;
 255                         insn = dfvm_insn_new(CHECK_EXISTS);
 256                         insn->arg1 = val1;
 257                         dfw_append_insn(dfw, insn);
 258
 259                         /* Record the FIELD_ID in hash of interesting fields. */
 260                         while (hfinfo) {
 261                                 g_hash_table_insert(dfw->interesting_fields,
 262                                         GINT_TO_POINTER(hfinfo->id),
 263                                         GUINT_TO_POINTER(TRUE));
 264                                 hfinfo = hfinfo->same_name_next;
 265                         }
 266
 267                         break;
 268
 269                 case TEST_OP_NOT:
 270                         gencode(dfw, st_arg1);
 271                         insn = dfvm_insn_new(NOT);
 272                         dfw_append_insn(dfw, insn);
 273                         break;
 274
 275                 case TEST_OP_AND:
 276                         gencode(dfw, st_arg1);
 277
 278                         insn = dfvm_insn_new(IF_FALSE_GOTO);
 279                         val1 = dfvm_value_new(INSN_NUMBER);
 280                         insn->arg1 = val1;
 281                         dfw_append_insn(dfw, insn);
 282
 283                         gencode(dfw, st_arg2);
 284                         val1->value.numeric = dfw->next_insn_id;
 285                         break;
 286
 287                 case TEST_OP_OR:
 288                         gencode(dfw, st_arg1);
 289
 290                         insn = dfvm_insn_new(IF_TRUE_GOTO);
 291                         val1 = dfvm_value_new(INSN_NUMBER);
 292                         insn->arg1 = val1;
 293                         dfw_append_insn(dfw, insn);
 294
 295                         gencode(dfw, st_arg2);
 296                         val1->value.numeric = dfw->next_insn_id;
 297                         break;
 298
 299                 case TEST_OP_EQ:
 300                         gen_relation(dfw, ANY_EQ, st_arg1, st_arg2);
 301                         break;
 302
 303                 case TEST_OP_NE:
 304                         gen_relation(dfw, ANY_NE, st_arg1, st_arg2);
 305                         break;
 306
 307                 case TEST_OP_GT:
 308                         gen_relation(dfw, ANY_GT, st_arg1, st_arg2);
 309                         break;
 310
 311                 case TEST_OP_GE:
 312                         gen_relation(dfw, ANY_GE, st_arg1, st_arg2);
 313                         break;
 314
 315                 case TEST_OP_LT:
 316                         gen_relation(dfw, ANY_LT, st_arg1, st_arg2);
 317                         break;
 318
 319                 case TEST_OP_LE:
 320                         gen_relation(dfw, ANY_LE, st_arg1, st_arg2);
 321                         break;
 322         }
 323 }
 324
 325 static void
 326 gencode(dfwork_t *dfw, stnode_t *st_node)
 327 {
 328         const char      *name;
 329
 330         name = stnode_type_name(st_node);
 331
 332         switch (stnode_type_id(st_node)) {
 333                 case STTYPE_TEST:
 334                         gen_test(dfw, st_node);
 335                         break;
 336                 default:
 337                         g_assert_not_reached();
 338         }
 339 }
 340
 341
 342 void
 343 dfw_gencode(dfwork_t *dfw)
 344 {
 345         dfw->insns = g_ptr_array_new();
 346         dfw->loaded_fields = g_hash_table_new(g_direct_hash, g_direct_equal);
 347         dfw->interesting_fields = g_hash_table_new(g_direct_hash, g_direct_equal);
 348         gencode(dfw, dfw->st_root);
 349         dfw_append_insn(dfw, dfvm_insn_new(RETURN));
 350 }
 351
 352
 353
 354 typedef struct {
 355     int i;
 356     int *fields;
 357 } hash_key_iterator;
 358
 359 static void
 360 get_hash_key(gpointer key, gpointer value _U_, gpointer user_data)
 361 {
 362     int field_id = GPOINTER_TO_INT(key);
 363     hash_key_iterator *hki = user_data;
 364
 365     hki->fields[hki->i] = field_id;
 366     hki->i++;
 367 }
 368
 369 int*
 370 dfw_interesting_fields(dfwork_t *dfw, int *caller_num_fields)
 371 {
 372     int num_fields = g_hash_table_size(dfw->interesting_fields);
 373
 374     hash_key_iterator hki;
 375
 376     if (num_fields == 0) {
 377         *caller_num_fields = 0;
 378         return NULL;
 379     }
 380
 381     hki.fields = g_new(int, num_fields);
 382     hki.i = 0;
 383
 384     g_hash_table_foreach(dfw->interesting_fields, get_hash_key, &hki);
 385     *caller_num_fields = num_fields;
 386     return hki.fields;
 387 }