epan/dfilter/gencode.c

   1 /*
   2  * $Id: gencode.c,v 1.4 2001/12/18 19:09:06 gram Exp $
   3  *
   4  * Ethereal - Network traffic analyzer
   5  * By Gerald Combs <gerald@zing.org>
   6  * Copyright 2001 Gerald Combs
   7  *
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version 2
  12  * of the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  22  */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include "config.h"
  26 #endif
  27
  28 #include "dfilter-int.h"
  29 #include "dfvm.h"
  30 #include "syntax-tree.h"
  31 #include "sttype-range.h"
  32 #include "sttype-test.h"
  33 #include "ftypes/ftypes.h"
  34 #include "gdebug.h"
  35
  36 static void
  37 gencode(dfwork_t *dfw, stnode_t *st_node);
  38
  39 static void
  40 dfw_append_insn(dfwork_t *dfw, dfvm_insn_t *insn)
  41 {
  42         insn->id = dfw->next_insn_id;
  43         dfw->next_insn_id++;
  44         g_ptr_array_add(dfw->insns, insn);
  45 }
  46
  47 /* returns register number */
  48 static int
  49 dfw_append_read_tree(dfwork_t *dfw, int field_id)
  50 {
  51         dfvm_insn_t     *insn;
  52         dfvm_value_t    *val1, *val2;
  53         int             reg = -1;
  54
  55         /* Keep track of which registers
  56          * were used for which field_id's so that we
  57          * can re-use registers. */
  58         reg = GPOINTER_TO_UINT(
  59                         g_hash_table_lookup(dfw->loaded_fields,
  60                         GINT_TO_POINTER(field_id)));
  61         if (reg) {
  62                 /* Reg's are stored in has as reg+1, so
  63                  * that the non-existence of a field_id in
  64                  * the hash, or 0, can be differentiated from
  65                  * a field_id being loaded into register #0. */
  66                 reg--;
  67         }
  68         else {
  69                 reg = dfw->next_register++;
  70                 g_hash_table_insert(dfw->loaded_fields,
  71                         GUINT_TO_POINTER(field_id),
  72                         GUINT_TO_POINTER(reg + 1));
  73
  74         /* Record the FIELD_ID in hash of interesting fields. */
  75         g_hash_table_insert(dfw->interesting_fields,
  76             GINT_TO_POINTER(field_id), GUINT_TO_POINTER(TRUE));
  77         }
  78
  79         insn = dfvm_insn_new(READ_TREE);
  80         val1 = dfvm_value_new(FIELD_ID);
  81         val1->value.numeric = field_id;
  82         val2 = dfvm_value_new(REGISTER);
  83         val2->value.numeric = reg;
  84
  85         insn->arg1 = val1;
  86         insn->arg2 = val2;
  87         dfw_append_insn(dfw, insn);
  88
  89         return reg;
  90 }
  91
  92 /* returns register number */
  93 static int
  94 dfw_append_put_fvalue(dfwork_t *dfw, fvalue_t *fv)
  95 {
  96         dfvm_insn_t     *insn;
  97         dfvm_value_t    *val1, *val2;
  98         int             reg;
  99
 100         insn = dfvm_insn_new(PUT_FVALUE);
 101         val1 = dfvm_value_new(FVALUE);
 102         val1->value.fvalue = fv;
 103         val2 = dfvm_value_new(REGISTER);
 104         reg = dfw->next_register++;
 105         val2->value.numeric = reg;
 106         insn->arg1 = val1;
 107         insn->arg2 = val2;
 108         dfw_append_insn(dfw, insn);
 109
 110         return reg;
 111 }
 112
 113 /* returns register number */
 114 static int
 115 dfw_append_mk_range(dfwork_t *dfw, stnode_t *node)
 116 {
 117         int                     hf_reg, reg;
 118         header_field_info       *hfinfo;
 119         dfvm_insn_t             *insn;
 120         dfvm_value_t            *val;
 121
 122         hfinfo = sttype_range_hfinfo(node);
 123         hf_reg = dfw_append_read_tree(dfw, hfinfo->id);
 124
 125         insn = dfvm_insn_new(MK_RANGE);
 126
 127         val = dfvm_value_new(REGISTER);
 128         val->value.numeric = hf_reg;
 129         insn->arg1 = val;
 130
 131         val = dfvm_value_new(REGISTER);
 132         reg =dfw->next_register++;
 133         val->value.numeric = reg;
 134         insn->arg2 = val;
 135
 136         val = dfvm_value_new(DRANGE);
 137         val->value.drange = sttype_range_drange(node);
 138         insn->arg3 = val;
 139
 140         sttype_range_remove_drange(node);
 141
 142         dfw_append_insn(dfw, insn);
 143
 144         return reg;
 145 }
 146
 147
 148 static void
 149 gen_relation(dfwork_t *dfw, dfvm_opcode_t op, stnode_t *st_arg1, stnode_t *st_arg2)
 150 {
 151         sttype_id_t     type1, type2;
 152         dfvm_insn_t     *insn;
 153         dfvm_value_t    *val1, *val2;
 154         dfvm_value_t    *jmp1 = NULL, *jmp2 = NULL;
 155         int             reg1 = -1, reg2 = -1;
 156         header_field_info       *hfinfo;
 157
 158         type1 = stnode_type_id(st_arg1);
 159         type2 = stnode_type_id(st_arg2);
 160
 161         if (type1 == STTYPE_FIELD) {
 162                 hfinfo = stnode_data(st_arg1);
 163                 reg1 = dfw_append_read_tree(dfw, hfinfo->id);
 164
 165                 insn = dfvm_insn_new(IF_FALSE_GOTO);
 166                 jmp1 = dfvm_value_new(INSN_NUMBER);
 167                 insn->arg1 = jmp1;
 168                 dfw_append_insn(dfw, insn);
 169         }
 170         else if (type1 == STTYPE_FVALUE) {
 171                 reg1 = dfw_append_put_fvalue(dfw, stnode_data(st_arg1));
 172         }
 173         else if (type1 == STTYPE_RANGE) {
 174                 reg1 = dfw_append_mk_range(dfw, st_arg1);
 175         }
 176         else {
 177                 g_assert_not_reached();
 178         }
 179
 180         if (type2 == STTYPE_FIELD) {
 181                 hfinfo = stnode_data(st_arg2);
 182                 reg2 = dfw_append_read_tree(dfw, hfinfo->id);
 183
 184                 insn = dfvm_insn_new(IF_FALSE_GOTO);
 185                 jmp2 = dfvm_value_new(INSN_NUMBER);
 186                 insn->arg1 = jmp2;
 187                 dfw_append_insn(dfw, insn);
 188         }
 189         else if (type2 == STTYPE_FVALUE) {
 190                 reg2 = dfw_append_put_fvalue(dfw, stnode_data(st_arg2));
 191         }
 192         else {
 193                 g_assert_not_reached();
 194         }
 195
 196         insn = dfvm_insn_new(op);
 197         val1 = dfvm_value_new(REGISTER);
 198         val1->value.numeric = reg1;
 199         val2 = dfvm_value_new(REGISTER);
 200         val2->value.numeric = reg2;
 201         insn->arg1 = val1;
 202         insn->arg2 = val2;
 203         dfw_append_insn(dfw, insn);
 204
 205         if (jmp1) {
 206                 jmp1->value.numeric = dfw->next_insn_id;
 207         }
 208
 209         if (jmp2) {
 210                 jmp2->value.numeric = dfw->next_insn_id;
 211         }
 212 }
 213
 214
 215 static void
 216 gen_test(dfwork_t *dfw, stnode_t *st_node)
 217 {
 218         test_op_t       st_op;
 219         stnode_t        *st_arg1, *st_arg2;
 220         dfvm_value_t    *val1;
 221         dfvm_insn_t     *insn;
 222
 223         header_field_info       *hfinfo;
 224
 225         sttype_test_get(st_node, &st_op, &st_arg1, &st_arg2);
 226
 227         switch (st_op) {
 228                 case TEST_OP_UNINITIALIZED:
 229                         g_assert_not_reached();
 230                         break;
 231
 232                 case TEST_OP_EXISTS:
 233                         val1 = dfvm_value_new(FIELD_ID);
 234                         hfinfo = stnode_data(st_arg1);
 235                         val1->value.numeric = hfinfo->id;
 236                         insn = dfvm_insn_new(CHECK_EXISTS);
 237                         insn->arg1 = val1;
 238                         dfw_append_insn(dfw, insn);
 239
 240             /* Record the FIELD_ID in hash of interesting fields. */
 241             g_hash_table_insert(dfw->interesting_fields,
 242                 GINT_TO_POINTER(hfinfo->id), GUINT_TO_POINTER(TRUE));
 243
 244                         break;
 245
 246                 case TEST_OP_NOT:
 247                         gencode(dfw, st_arg1);
 248                         insn = dfvm_insn_new(NOT);
 249                         dfw_append_insn(dfw, insn);
 250                         break;
 251
 252                 case TEST_OP_AND:
 253                         gencode(dfw, st_arg1);
 254
 255                         insn = dfvm_insn_new(IF_FALSE_GOTO);
 256                         val1 = dfvm_value_new(INSN_NUMBER);
 257                         insn->arg1 = val1;
 258                         dfw_append_insn(dfw, insn);
 259
 260                         gencode(dfw, st_arg2);
 261                         val1->value.numeric = dfw->next_insn_id;
 262                         break;
 263
 264                 case TEST_OP_OR:
 265                         gencode(dfw, st_arg1);
 266
 267                         insn = dfvm_insn_new(IF_TRUE_GOTO);
 268                         val1 = dfvm_value_new(INSN_NUMBER);
 269                         insn->arg1 = val1;
 270                         dfw_append_insn(dfw, insn);
 271
 272                         gencode(dfw, st_arg2);
 273                         val1->value.numeric = dfw->next_insn_id;
 274                         break;
 275
 276                 case TEST_OP_EQ:
 277                         gen_relation(dfw, ANY_EQ, st_arg1, st_arg2);
 278                         break;
 279
 280                 case TEST_OP_NE:
 281                         gen_relation(dfw, ANY_NE, st_arg1, st_arg2);
 282                         break;
 283
 284                 case TEST_OP_GT:
 285                         gen_relation(dfw, ANY_GT, st_arg1, st_arg2);
 286                         break;
 287
 288                 case TEST_OP_GE:
 289                         gen_relation(dfw, ANY_GE, st_arg1, st_arg2);
 290                         break;
 291
 292                 case TEST_OP_LT:
 293                         gen_relation(dfw, ANY_LT, st_arg1, st_arg2);
 294                         break;
 295
 296                 case TEST_OP_LE:
 297                         gen_relation(dfw, ANY_LE, st_arg1, st_arg2);
 298                         break;
 299         }
 300 }
 301
 302 static void
 303 gencode(dfwork_t *dfw, stnode_t *st_node)
 304 {
 305         const char      *name;
 306
 307         name = stnode_type_name(st_node);
 308
 309         switch (stnode_type_id(st_node)) {
 310                 case STTYPE_TEST:
 311                         gen_test(dfw, st_node);
 312                         break;
 313                 default:
 314                         g_assert_not_reached();
 315         }
 316 }
 317
 318
 319 void
 320 dfw_gencode(dfwork_t *dfw)
 321 {
 322         dfw->insns = g_ptr_array_new();
 323         dfw->loaded_fields = g_hash_table_new(g_direct_hash, g_direct_equal);
 324         dfw->interesting_fields = g_hash_table_new(g_direct_hash, g_direct_equal);
 325         gencode(dfw, dfw->st_root);
 326         dfw_append_insn(dfw, dfvm_insn_new(RETURN));
 327 }
 328
 329
 330
 331 typedef struct {
 332     int i;
 333     int *fields;
 334 } hash_key_iterator;
 335
 336 static void
 337 get_hash_key(gpointer key, gpointer value, gpointer user_data)
 338 {
 339     int field_id = GPOINTER_TO_INT(key);
 340     hash_key_iterator *hki = user_data;
 341
 342     hki->fields[hki->i] = field_id;
 343     hki->i++;
 344 }
 345
 346 int*
 347 dfw_interesting_fields(dfwork_t *dfw, int *caller_num_fields)
 348 {
 349     int num_fields = g_hash_table_size(dfw->interesting_fields);
 350
 351     hash_key_iterator hki;
 352
 353     if (num_fields == 0) {
 354         *caller_num_fields = 0;
 355         return NULL;
 356     }
 357
 358     hki.fields = g_new(int, num_fields);
 359     hki.i = 0;
 360
 361     g_hash_table_foreach(dfw->interesting_fields, get_hash_key, &hki);
 362     *caller_num_fields = num_fields;
 363     return hki.fields;
 364 }