forked from osmocom/wireshark
709 lines
14 KiB
C
709 lines
14 KiB
C
/*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 2001 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include "dfvm.h"
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#include <ftypes/ftypes.h>
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#include <wsutil/ws_assert.h>
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dfvm_insn_t*
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dfvm_insn_new(dfvm_opcode_t op)
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{
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dfvm_insn_t *insn;
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insn = g_new(dfvm_insn_t, 1);
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insn->op = op;
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insn->arg1 = NULL;
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insn->arg2 = NULL;
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insn->arg3 = NULL;
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insn->arg4 = NULL;
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return insn;
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}
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static void
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dfvm_value_free(dfvm_value_t *v)
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{
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switch (v->type) {
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case FVALUE:
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fvalue_free(v->value.fvalue);
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break;
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case DRANGE:
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drange_free(v->value.drange);
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break;
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case PCRE:
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ws_regex_free(v->value.pcre);
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break;
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default:
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/* nothing */
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;
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}
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g_free(v);
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}
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dfvm_value_t*
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dfvm_value_ref(dfvm_value_t *v)
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{
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if (v == NULL)
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return NULL;
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v->ref_count++;
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return v;
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}
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void
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dfvm_value_unref(dfvm_value_t *v)
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{
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ws_assert(v);
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v->ref_count--;
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if (v->ref_count > 0)
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return;
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dfvm_value_free(v);
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}
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void
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dfvm_insn_free(dfvm_insn_t *insn)
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{
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if (insn->arg1) {
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dfvm_value_unref(insn->arg1);
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}
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if (insn->arg2) {
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dfvm_value_unref(insn->arg2);
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}
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if (insn->arg3) {
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dfvm_value_unref(insn->arg3);
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}
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if (insn->arg4) {
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dfvm_value_unref(insn->arg4);
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}
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g_free(insn);
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}
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dfvm_value_t*
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dfvm_value_new(dfvm_value_type_t type)
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{
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dfvm_value_t *v;
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v = g_new(dfvm_value_t, 1);
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v->type = type;
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v->ref_count = 0;
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return v;
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}
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dfvm_value_t*
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dfvm_value_new_fvalue(fvalue_t *fv)
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{
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dfvm_value_t *v = dfvm_value_new(FVALUE);
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v->value.fvalue = fv;
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return v;
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}
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dfvm_value_t*
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dfvm_value_new_hfinfo(header_field_info *hfinfo)
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{
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dfvm_value_t *v = dfvm_value_new(HFINFO);
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v->value.hfinfo = hfinfo;
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return v;
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}
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dfvm_value_t*
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dfvm_value_new_register(int reg)
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{
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dfvm_value_t *v = dfvm_value_new(REGISTER);
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v->value.numeric = reg;
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return v;
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}
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dfvm_value_t*
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dfvm_value_new_drange(drange_t *dr)
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{
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dfvm_value_t *v = dfvm_value_new(DRANGE);
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v->value.drange = dr;
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return v;
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}
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dfvm_value_t*
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dfvm_value_new_funcdef(df_func_def_t *funcdef)
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{
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dfvm_value_t *v = dfvm_value_new(FUNCTION_DEF);
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v->value.funcdef = funcdef;
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return v;
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}
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dfvm_value_t*
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dfvm_value_new_pcre(ws_regex_t *re)
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{
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dfvm_value_t *v = dfvm_value_new(PCRE);
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v->value.pcre = re;
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return v;
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}
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char *
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dfvm_value_tostr(dfvm_value_t *v)
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{
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char *s, *aux;
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if (!v)
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return NULL;
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switch (v->type) {
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case HFINFO:
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s = ws_strdup(v->value.hfinfo->abbrev);
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break;
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case FVALUE:
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aux = fvalue_to_debug_repr(NULL, v->value.fvalue);
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s = ws_strdup_printf("%s <%s>",
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aux, fvalue_type_name(v->value.fvalue));
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g_free(aux);
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break;
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case DRANGE:
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s = drange_tostr(v->value.drange);
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break;
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case PCRE:
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s = ws_strdup(ws_regex_pattern(v->value.pcre));
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break;
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case REGISTER:
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s = ws_strdup_printf("reg#%u", v->value.numeric);
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break;
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case FUNCTION_DEF:
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s = ws_strdup(v->value.funcdef->name);
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break;
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default:
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s = ws_strdup("FIXME");
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}
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return s;
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}
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void
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dfvm_dump(FILE *f, dfilter_t *df)
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{
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int id, length;
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dfvm_insn_t *insn;
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dfvm_value_t *arg1, *arg2, *arg3, *arg4;
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char *arg1_str, *arg2_str, *arg3_str, *arg4_str;
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fprintf(f, "Instructions:\n");
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length = df->insns->len;
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for (id = 0; id < length; id++) {
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insn = g_ptr_array_index(df->insns, id);
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arg1 = insn->arg1;
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arg2 = insn->arg2;
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arg3 = insn->arg3;
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arg4 = insn->arg4;
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arg1_str = dfvm_value_tostr(arg1);
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arg2_str = dfvm_value_tostr(arg2);
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arg3_str = dfvm_value_tostr(arg3);
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arg4_str = dfvm_value_tostr(arg4);
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switch (insn->op) {
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case CHECK_EXISTS:
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fprintf(f, "%05d CHECK_EXISTS\t%s\n",
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id, arg1_str);
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break;
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case READ_TREE:
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fprintf(f, "%05d READ_TREE\t\t%s -> %s\n",
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id, arg1_str, arg2_str);
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break;
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case CALL_FUNCTION:
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fprintf(f, "%05d CALL_FUNCTION\t%s(",
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id, arg1_str);
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if (arg3_str) {
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fprintf(f, "%s", arg3_str);
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}
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if (arg4_str) {
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fprintf(f, ", %s", arg4_str);
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}
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fprintf(f, ") -> %s\n", arg2_str);
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break;
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case MK_RANGE:
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arg3 = insn->arg3;
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fprintf(f, "%05d MK_RANGE\t\t%s[%s] -> %s\n",
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id, arg1_str, arg2_str, arg3_str);
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break;
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case ALL_EQ:
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fprintf(f, "%05d ALL_EQ\t\t%s === %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_EQ:
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fprintf(f, "%05d ANY_EQ\t\t%s == %s\n",
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id, arg1_str, arg2_str);
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break;
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case ALL_NE:
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fprintf(f, "%05d ALL_NE\t\t%s != %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_NE:
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fprintf(f, "%05d ANY_NE\t\t%s !== %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_GT:
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fprintf(f, "%05d ANY_GT\t\t%s > %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_GE:
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fprintf(f, "%05d ANY_GE\t\t%s >= %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_LT:
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fprintf(f, "%05d ANY_LT\t\t%s < %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_LE:
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fprintf(f, "%05d ANY_LE\t\t%s <= %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_BITWISE_AND:
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fprintf(f, "%05d ANY_BITWISE_AND\t%s & %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_CONTAINS:
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fprintf(f, "%05d ANY_CONTAINS\t%s contains %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_MATCHES:
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fprintf(f, "%05d ANY_MATCHES\t%s matches %s\n",
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id, arg1_str, arg2_str);
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break;
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case ANY_IN_RANGE:
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fprintf(f, "%05d ANY_IN_RANGE\t%s in { %s .. %s }\n",
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id, arg1_str, arg2_str, arg3_str);
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break;
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case NOT:
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fprintf(f, "%05d NOT\n", id);
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break;
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case RETURN:
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fprintf(f, "%05d RETURN\n", id);
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break;
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case IF_TRUE_GOTO:
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fprintf(f, "%05d IF_TRUE_GOTO\t%u\n",
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id, arg1->value.numeric);
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break;
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case IF_FALSE_GOTO:
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fprintf(f, "%05d IF_FALSE_GOTO\t%u\n",
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id, arg1->value.numeric);
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break;
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}
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g_free(arg1_str);
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g_free(arg2_str);
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g_free(arg3_str);
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g_free(arg4_str);
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}
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}
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/* Reads a field from the proto_tree and loads the fvalues into a register,
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* if that field has not already been read. */
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static gboolean
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read_tree(dfilter_t *df, proto_tree *tree,
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dfvm_value_t *arg1, dfvm_value_t *arg2)
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{
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GPtrArray *finfos;
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field_info *finfo;
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int i, len;
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GSList *fvalues = NULL;
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gboolean found_something = FALSE;
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header_field_info *hfinfo = arg1->value.hfinfo;
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int reg = arg2->value.numeric;
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/* Already loaded in this run of the dfilter? */
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if (df->attempted_load[reg]) {
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if (df->registers[reg]) {
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return TRUE;
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}
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else {
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return FALSE;
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}
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}
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df->attempted_load[reg] = TRUE;
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while (hfinfo) {
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finfos = proto_get_finfo_ptr_array(tree, hfinfo->id);
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if ((finfos == NULL) || (g_ptr_array_len(finfos) == 0)) {
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hfinfo = hfinfo->same_name_next;
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continue;
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}
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else {
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found_something = TRUE;
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}
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len = finfos->len;
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for (i = 0; i < len; i++) {
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finfo = g_ptr_array_index(finfos, i);
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fvalues = g_slist_prepend(fvalues, &finfo->value);
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}
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hfinfo = hfinfo->same_name_next;
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}
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if (!found_something) {
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return FALSE;
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}
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df->registers[reg] = fvalues;
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// These values are referenced only, do not try to free it later.
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df->owns_memory[reg] = FALSE;
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return TRUE;
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}
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enum match_how {
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MATCH_ANY,
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MATCH_ALL
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};
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typedef gboolean (*DFVMCompareFunc)(const fvalue_t*, const fvalue_t*);
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static gboolean
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cmp_test(enum match_how how, DFVMCompareFunc match_func,
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GSList *arg1, GSList *arg2)
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{
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GSList *list1, *list2;
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gboolean want_all = (how == MATCH_ALL);
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gboolean want_any = (how == MATCH_ANY);
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gboolean have_match;
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list1 = arg1;
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while (list1) {
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list2 = arg2;
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while (list2) {
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have_match = match_func(list1->data, list2->data);
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if (want_all && !have_match) {
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return FALSE;
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}
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else if (want_any && have_match) {
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return TRUE;
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}
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list2 = g_slist_next(list2);
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}
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list1 = g_slist_next(list1);
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}
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/* want_all || !want_any */
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return want_all;
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}
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/* cmp(A) <=> cmp(a1) OR cmp(a2) OR cmp(a3) OR ... */
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static gboolean
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any_test(dfilter_t *df, DFVMCompareFunc cmp,
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dfvm_value_t *arg1, dfvm_value_t *arg2)
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{
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ws_assert(arg1->type == REGISTER);
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GSList *list1 = df->registers[arg1->value.numeric];
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if (arg2->type == REGISTER) {
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return cmp_test(MATCH_ANY, cmp, list1, df->registers[arg2->value.numeric]);
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}
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if (arg2->type == FVALUE) {
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GSList list2;
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list2.data = arg2->value.fvalue;
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list2.next = NULL;
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return cmp_test(MATCH_ANY, cmp, list1, &list2);
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}
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ws_assert_not_reached();
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}
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/* cmp(A) <=> cmp(a1) AND cmp(a2) AND cmp(a3) AND ... */
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static gboolean
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all_test(dfilter_t *df, DFVMCompareFunc cmp,
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dfvm_value_t *arg1, dfvm_value_t *arg2)
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{
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ws_assert(arg1->type == REGISTER);
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GSList *list1 = df->registers[arg1->value.numeric];
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if (arg2->type == REGISTER) {
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return cmp_test(MATCH_ALL, cmp, list1, df->registers[arg2->value.numeric]);
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}
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if (arg2->type == FVALUE) {
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GSList list2;
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list2.data = arg2->value.fvalue;
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list2.next = NULL;
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return cmp_test(MATCH_ALL, cmp, list1, &list2);
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}
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ws_assert_not_reached();
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}
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static gboolean
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any_matches(dfilter_t *df, dfvm_value_t *arg1, dfvm_value_t *arg2)
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{
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GSList *list1 = df->registers[arg1->value.numeric];
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ws_regex_t *re = arg2->value.pcre;
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while (list1) {
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if (fvalue_matches(list1->data, re)) {
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return TRUE;
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}
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list1 = g_slist_next(list1);
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}
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return FALSE;
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}
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static gboolean
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any_in_range(dfilter_t *df, dfvm_value_t *arg1,
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dfvm_value_t *arg_low, dfvm_value_t *arg_high)
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{
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GSList *list1 = df->registers[arg1->value.numeric];
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fvalue_t *low = arg_low->value.fvalue;
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fvalue_t *high = arg_high->value.fvalue;
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while (list1) {
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if (fvalue_ge(list1->data, low) &&
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fvalue_le(list1->data, high)) {
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return TRUE;
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}
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list1 = g_slist_next(list1);
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}
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return FALSE;
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}
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static void
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free_owned_register(gpointer data, gpointer user_data _U_)
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{
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fvalue_free(data);
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}
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/* Clear registers that were populated during evaluation.
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* If we created the values, then these will be freed as well. */
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static void
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free_register_overhead(dfilter_t* df)
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{
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guint i;
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for (i = 0; i < df->num_registers; i++) {
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df->attempted_load[i] = FALSE;
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if (df->registers[i]) {
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if (df->owns_memory[i]) {
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g_slist_foreach(df->registers[i], free_owned_register, NULL);
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df->owns_memory[i] = FALSE;
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}
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g_slist_free(df->registers[i]);
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df->registers[i] = NULL;
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}
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}
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}
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/* Takes the list of fvalue_t's in a register, uses fvalue_slice()
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* to make a new list of fvalue_t's (which are ranges, or byte-slices),
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* and puts the new list into a new register. */
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static void
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mk_range(dfilter_t *df, dfvm_value_t *from_arg, dfvm_value_t *to_arg,
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dfvm_value_t *drange_arg)
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{
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GSList *from_list, *to_list;
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fvalue_t *old_fv, *new_fv;
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to_list = NULL;
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from_list = df->registers[from_arg->value.numeric];
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drange_t *drange = drange_arg->value.drange;
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while (from_list) {
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old_fv = from_list->data;
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new_fv = fvalue_slice(old_fv, drange);
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/* Assert here because semcheck.c should have
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* already caught the cases in which a slice
|
|
* cannot be made. */
|
|
ws_assert(new_fv);
|
|
to_list = g_slist_prepend(to_list, new_fv);
|
|
|
|
from_list = g_slist_next(from_list);
|
|
}
|
|
|
|
df->registers[to_arg->value.numeric] = to_list;
|
|
df->owns_memory[to_arg->value.numeric] = TRUE;
|
|
}
|
|
|
|
static gboolean
|
|
call_function(dfilter_t *df, dfvm_value_t *arg1, dfvm_value_t *arg2,
|
|
dfvm_value_t *arg3, dfvm_value_t *arg4)
|
|
{
|
|
df_func_def_t *funcdef;
|
|
GSList *param1 = NULL;
|
|
GSList *param2 = NULL;
|
|
GSList *retval = NULL;
|
|
gboolean accum;
|
|
|
|
funcdef = arg1->value.funcdef;
|
|
if (arg3) {
|
|
param1 = df->registers[arg3->value.numeric];
|
|
}
|
|
if (arg4) {
|
|
param2 = df->registers[arg4->value.numeric];
|
|
}
|
|
accum = funcdef->function(param1, param2, &retval);
|
|
|
|
df->registers[arg2->value.numeric] = retval;
|
|
// functions create a new value, so own it.
|
|
df->owns_memory[arg2->value.numeric] = TRUE;
|
|
return accum;
|
|
}
|
|
|
|
gboolean
|
|
dfvm_apply(dfilter_t *df, proto_tree *tree)
|
|
{
|
|
int id, length;
|
|
gboolean accum = TRUE;
|
|
dfvm_insn_t *insn;
|
|
dfvm_value_t *arg1;
|
|
dfvm_value_t *arg2;
|
|
dfvm_value_t *arg3 = NULL;
|
|
dfvm_value_t *arg4 = NULL;
|
|
header_field_info *hfinfo;
|
|
|
|
ws_assert(tree);
|
|
|
|
length = df->insns->len;
|
|
|
|
for (id = 0; id < length; id++) {
|
|
|
|
AGAIN:
|
|
insn = g_ptr_array_index(df->insns, id);
|
|
arg1 = insn->arg1;
|
|
arg2 = insn->arg2;
|
|
arg3 = insn->arg3;
|
|
arg4 = insn->arg4;
|
|
|
|
switch (insn->op) {
|
|
case CHECK_EXISTS:
|
|
hfinfo = arg1->value.hfinfo;
|
|
while(hfinfo) {
|
|
accum = proto_check_for_protocol_or_field(tree,
|
|
hfinfo->id);
|
|
if (accum) {
|
|
break;
|
|
}
|
|
else {
|
|
hfinfo = hfinfo->same_name_next;
|
|
}
|
|
}
|
|
break;
|
|
|
|
case READ_TREE:
|
|
accum = read_tree(df, tree, arg1, arg2);
|
|
break;
|
|
|
|
case CALL_FUNCTION:
|
|
accum = call_function(df, arg1, arg2, arg3, arg4);
|
|
break;
|
|
|
|
case MK_RANGE:
|
|
mk_range(df, arg1, arg2, arg3);
|
|
break;
|
|
|
|
case ALL_EQ:
|
|
accum = all_test(df, fvalue_eq, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_EQ:
|
|
accum = any_test(df, fvalue_eq, arg1, arg2);
|
|
break;
|
|
|
|
case ALL_NE:
|
|
accum = all_test(df, fvalue_ne, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_NE:
|
|
accum = any_test(df, fvalue_ne, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_GT:
|
|
accum = any_test(df, fvalue_gt, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_GE:
|
|
accum = any_test(df, fvalue_ge, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_LT:
|
|
accum = any_test(df, fvalue_lt, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_LE:
|
|
accum = any_test(df, fvalue_le, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_BITWISE_AND:
|
|
accum = any_test(df, fvalue_bitwise_and, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_CONTAINS:
|
|
accum = any_test(df, fvalue_contains, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_MATCHES:
|
|
accum = any_matches(df, arg1, arg2);
|
|
break;
|
|
|
|
case ANY_IN_RANGE:
|
|
accum = any_in_range(df, arg1, arg2, arg3);
|
|
break;
|
|
|
|
case NOT:
|
|
accum = !accum;
|
|
break;
|
|
|
|
case RETURN:
|
|
free_register_overhead(df);
|
|
return accum;
|
|
|
|
case IF_TRUE_GOTO:
|
|
if (accum) {
|
|
id = arg1->value.numeric;
|
|
goto AGAIN;
|
|
}
|
|
break;
|
|
|
|
case IF_FALSE_GOTO:
|
|
if (!accum) {
|
|
id = arg1->value.numeric;
|
|
goto AGAIN;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
ws_assert_not_reached();
|
|
}
|
|
|
|
/*
|
|
* Editor modelines - https://www.wireshark.org/tools/modelines.html
|
|
*
|
|
* Local variables:
|
|
* c-basic-offset: 8
|
|
* tab-width: 8
|
|
* indent-tabs-mode: t
|
|
* End:
|
|
*
|
|
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
|
|
* :indentSize=8:tabSize=8:noTabs=false:
|
|
*/
|