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path: root/epan/dfilter/semcheck.c
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/*
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 2001 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <string.h>

#include "dfilter-int.h"
#include "semcheck.h"
#include "syntax-tree.h"
#include "sttype-range.h"
#include "sttype-test.h"
#include "sttype-set.h"
#include "sttype-function.h"

#include <epan/exceptions.h>
#include <epan/packet.h>

#ifdef DEBUG_dfilter
#include <wsutil/ws_printf.h> /* ws_debug_printf */
#endif

#include <ftypes/ftypes-int.h>

/* Enable debug logging by defining AM_CFLAGS
 * so that it contains "-DDEBUG_dfilter".
 * Usage: DebugLog(("Error: string=%s\n", str)); */

#ifdef DEBUG_dfilter
#define DebugLog(x) \
	ws_debug_printf("%s:%u: ", __FILE__, __LINE__); \
	ws_debug_printf x; \
	fflush(stdout)
#else
#define DebugLog(x) ;
#endif

static void
semcheck(dfwork_t *dfw, stnode_t *st_node, GPtrArray *deprecated);

static stnode_t*
check_param_entity(dfwork_t *dfw, stnode_t *st_node);

typedef gboolean (*FtypeCanFunc)(enum ftenum);

/* Compares to ftenum_t's and decides if they're
 * compatible or not (if they're the same basic type) */
static gboolean
compatible_ftypes(ftenum_t a, ftenum_t b)
{
	switch (a) {
		case FT_NONE:
		case FT_PROTOCOL:
		case FT_FLOAT:		/* XXX - should be able to compare with INT */
		case FT_DOUBLE:		/* XXX - should be able to compare with INT */
		case FT_ABSOLUTE_TIME:
		case FT_RELATIVE_TIME:
		case FT_IEEE_11073_SFLOAT:
		case FT_IEEE_11073_FLOAT:
		case FT_IPv4:
		case FT_IPv6:
		case FT_IPXNET:
		case FT_INT40:		/* XXX - should be able to compare with INT */
		case FT_UINT40:		/* XXX - should be able to compare with INT */
		case FT_INT48:		/* XXX - should be able to compare with INT */
		case FT_UINT48:		/* XXX - should be able to compare with INT */
		case FT_INT56:		/* XXX - should be able to compare with INT */
		case FT_UINT56:		/* XXX - should be able to compare with INT */
		case FT_INT64:		/* XXX - should be able to compare with INT */
		case FT_UINT64:		/* XXX - should be able to compare with INT */
		case FT_EUI64:		/* XXX - should be able to compare with INT */
			return a == b;

		case FT_ETHER:
		case FT_BYTES:
		case FT_UINT_BYTES:
		case FT_GUID:
		case FT_OID:
		case FT_AX25:
		case FT_VINES:
		case FT_FCWWN:
		case FT_REL_OID:
		case FT_SYSTEM_ID:

			return (b == FT_ETHER || b == FT_BYTES || b == FT_UINT_BYTES || b == FT_GUID || b == FT_OID || b == FT_AX25 || b == FT_VINES || b == FT_FCWWN || b == FT_REL_OID || b == FT_SYSTEM_ID);

		case FT_BOOLEAN:
		case FT_FRAMENUM:
		case FT_CHAR:
		case FT_UINT8:
		case FT_UINT16:
		case FT_UINT24:
		case FT_UINT32:
		case FT_INT8:
		case FT_INT16:
		case FT_INT24:
		case FT_INT32:
			switch (b) {
				case FT_BOOLEAN:
				case FT_FRAMENUM:
				case FT_CHAR:
				case FT_UINT8:
				case FT_UINT16:
				case FT_UINT24:
				case FT_UINT32:
				case FT_INT8:
				case FT_INT16:
				case FT_INT24:
				case FT_INT32:
					return TRUE;
				default:
					return FALSE;
			}

		case FT_STRING:
		case FT_STRINGZ:
		case FT_UINT_STRING:
		case FT_STRINGZPAD:
			switch (b) {
				case FT_STRING:
				case FT_STRINGZ:
				case FT_UINT_STRING:
				case FT_STRINGZPAD:
					return TRUE;
				default:
					return FALSE;
			}

		case FT_PCRE:
		case FT_NUM_TYPES:
			g_assert_not_reached();
	}

	g_assert_not_reached();
	return FALSE;
}

/* Gets an fvalue from a string, and sets the error message on failure. */
static fvalue_t*
dfilter_fvalue_from_unparsed(dfwork_t *dfw, ftenum_t ftype, const char *s, gboolean allow_partial_value)
{
	/*
	 * Don't set the error message if it's already set.
	 */
	return fvalue_from_unparsed(ftype, s, allow_partial_value,
	    dfw->error_message == NULL ? &dfw->error_message : NULL);
}

/* Gets an fvalue from a string, and sets the error message on failure. */
static fvalue_t*
dfilter_fvalue_from_string(dfwork_t *dfw, ftenum_t ftype, const char *s)
{
	return fvalue_from_string(ftype, s,
	    dfw->error_message == NULL ? &dfw->error_message : NULL);
}

/* Creates a FT_UINT32 fvalue with a given value. */
static fvalue_t*
mk_uint32_fvalue(guint32 val)
{
	fvalue_t *fv;

	fv = fvalue_new(FT_UINT32);
	fvalue_set_uinteger(fv, val);

	return fv;
}

/* Creates a FT_UINT64 fvalue with a given value. */
static fvalue_t*
mk_uint64_fvalue(guint64 val)
{
	fvalue_t *fv;

	fv = fvalue_new(FT_UINT64);
	fvalue_set_uinteger64(fv, val);

	return fv;
}

/* Try to make an fvalue from a string using a value_string or true_false_string.
 * This works only for ftypes that are integers. Returns the created fvalue_t*
 * or NULL if impossible. */
static fvalue_t*
mk_fvalue_from_val_string(dfwork_t *dfw, header_field_info *hfinfo, char *s)
{
	static const true_false_string  default_tf = { "True", "False" };
	const true_false_string		*tf = &default_tf;

	/* Early return? */
	switch(hfinfo->type) {
		case FT_NONE:
		case FT_PROTOCOL:
		case FT_FLOAT:
		case FT_DOUBLE:
		case FT_IEEE_11073_SFLOAT:
		case FT_IEEE_11073_FLOAT:
		case FT_ABSOLUTE_TIME:
		case FT_RELATIVE_TIME:
		case FT_IPv4:
		case FT_IPv6:
		case FT_IPXNET:
		case FT_AX25:
		case FT_VINES:
		case FT_FCWWN:
		case FT_ETHER:
		case FT_BYTES:
		case FT_UINT_BYTES:
		case FT_STRING:
		case FT_STRINGZ:
		case FT_UINT_STRING:
		case FT_STRINGZPAD:
		case FT_EUI64:
		case FT_PCRE:
		case FT_GUID:
		case FT_OID:
		case FT_REL_OID:
		case FT_SYSTEM_ID:
		case FT_FRAMENUM: /* hfinfo->strings contains ft_framenum_type_t, not strings */
			return NULL;

		case FT_BOOLEAN:
		case FT_CHAR:
		case FT_UINT8:
		case FT_UINT16:
		case FT_UINT24:
		case FT_UINT32:
		case FT_UINT40:
		case FT_UINT48:
		case FT_UINT56:
		case FT_UINT64:
		case FT_INT8:
		case FT_INT16:
		case FT_INT24:
		case FT_INT32:
		case FT_INT40:
		case FT_INT48:
		case FT_INT56:
		case FT_INT64:
			break;

		case FT_NUM_TYPES:
			g_assert_not_reached();
	}

	/* TRUE/FALSE *always* exist for FT_BOOLEAN. */
	if (hfinfo->type == FT_BOOLEAN) {
		if (hfinfo->strings) {
			tf = (const true_false_string *)hfinfo->strings;
		}

		if (g_ascii_strcasecmp(s, tf->true_string) == 0) {
			return mk_uint64_fvalue(TRUE);
		}
		else if (g_ascii_strcasecmp(s, tf->false_string) == 0) {
			return mk_uint64_fvalue(FALSE);
		}
		else {
			/*
			 * Prefer this error message to whatever error message
			 * has already been set.
			 */
			g_free(dfw->error_message);
			dfw->error_message = NULL;
			dfilter_fail(dfw, "\"%s\" cannot be found among the possible values for %s.",
				s, hfinfo->abbrev);
			return NULL;
		}
	}

	/* Do val_strings exist? */
	if (!hfinfo->strings) {
		dfilter_fail(dfw, "%s cannot accept strings as values.",
				hfinfo->abbrev);
		return NULL;
	}

	/* Reset the error message, since *something* interesting will happen,
	 * and the error message will be more interesting than any error message
	 * I happen to have now. */
	g_free(dfw->error_message);
	dfw->error_message = NULL;

	if (hfinfo->display & BASE_RANGE_STRING) {
		dfilter_fail(dfw, "\"%s\" cannot accept [range] strings as values.",
				hfinfo->abbrev);
	}
	else if (hfinfo->display & BASE_VAL64_STRING) {
		const val64_string *vals = (const val64_string *)hfinfo->strings;

		while (vals->strptr != NULL) {
			if (g_ascii_strcasecmp(s, vals->strptr) == 0) {
				return mk_uint64_fvalue(vals->value);
			}
			vals++;
		}
		dfilter_fail(dfw, "\"%s\" cannot be found among the possible values for %s.",
				s, hfinfo->abbrev);
	}
	else if (hfinfo->display == BASE_CUSTOM) {
		/*  If a user wants to match against a custom string, we would
		 *  somehow have to have the integer value here to pass it in
		 *  to the custom-display function.  But we don't have an
		 *  integer, we have the string they're trying to match.
		 *  -><-
		 */
		dfilter_fail(dfw, "\"%s\" cannot accept [custom] strings as values.",
				hfinfo->abbrev);
	}
	else {
		const value_string *vals = (const value_string *)hfinfo->strings;
		if (hfinfo->display & BASE_EXT_STRING)
			vals = VALUE_STRING_EXT_VS_P((const value_string_ext *) vals);

		while (vals->strptr != NULL) {
			if (g_ascii_strcasecmp(s, vals->strptr) == 0) {
				return mk_uint32_fvalue(vals->value);
			}
			vals++;
		}
		dfilter_fail(dfw, "\"%s\" cannot be found among the possible values for %s.",
				s, hfinfo->abbrev);
	}
	return NULL;
}

static gboolean
is_bytes_type(enum ftenum type)
{
	switch(type) {
		case FT_AX25:
		case FT_VINES:
		case FT_FCWWN:
		case FT_ETHER:
		case FT_BYTES:
		case FT_UINT_BYTES:
		case FT_IPv6:
		case FT_GUID:
		case FT_OID:
		case FT_REL_OID:
		case FT_SYSTEM_ID:
			return TRUE;

		case FT_NONE:
		case FT_PROTOCOL:
		case FT_FLOAT:
		case FT_DOUBLE:
		case FT_IEEE_11073_SFLOAT:
		case FT_IEEE_11073_FLOAT:
		case FT_ABSOLUTE_TIME:
		case FT_RELATIVE_TIME:
		case FT_IPv4:
		case FT_IPXNET:
		case FT_STRING:
		case FT_STRINGZ:
		case FT_UINT_STRING:
		case FT_STRINGZPAD:
		case FT_BOOLEAN:
		case FT_FRAMENUM:
		case FT_CHAR:
		case FT_UINT8:
		case FT_UINT16:
		case FT_UINT24:
		case FT_UINT32:
		case FT_UINT40:
		case FT_UINT48:
		case FT_UINT56:
		case FT_UINT64:
		case FT_INT8:
		case FT_INT16:
		case FT_INT24:
		case FT_INT32:
		case FT_INT40:
		case FT_INT48:
		case FT_INT56:
		case FT_INT64:
		case FT_PCRE:
		case FT_EUI64:
			return FALSE;

		case FT_NUM_TYPES:
			g_assert_not_reached();
	}

	g_assert_not_reached();
	return FALSE;
}

/* Check the semantics of an existence test. */
static void
check_exists(dfwork_t *dfw, stnode_t *st_arg1)
{
#ifdef DEBUG_dfilter
	static guint i = 0;
#endif

	DebugLog(("   4 check_exists() [%u]\n", i++));
	switch (stnode_type_id(st_arg1)) {
		case STTYPE_FIELD:
			/* This is OK */
			break;
		case STTYPE_STRING:
		case STTYPE_CHARCONST:
		case STTYPE_UNPARSED:
			dfilter_fail(dfw, "\"%s\" is neither a field nor a protocol name.",
					(char *)stnode_data(st_arg1));
			THROW(TypeError);
			break;

		case STTYPE_RANGE:
			/*
			 * XXX - why not?  Shouldn't "eth[3:2]" mean
			 * "check whether the 'eth' field is present and
			 * has at least 2 bytes starting at an offset of
			 * 3"?
			 */
			dfilter_fail(dfw, "You cannot test whether a range is present.");
			THROW(TypeError);
			break;

		case STTYPE_FUNCTION:
			/* XXX - Maybe we should change functions so they can return fields,
			 * in which case the 'exist' should be fine. */
			dfilter_fail(dfw, "You cannot test whether a function is present.");
			THROW(TypeError);
			break;

		case STTYPE_UNINITIALIZED:
		case STTYPE_TEST:
		case STTYPE_INTEGER:
		case STTYPE_FVALUE:
		case STTYPE_SET:
		case STTYPE_NUM_TYPES:
			g_assert_not_reached();
	}
}

struct check_drange_sanity_args {
	dfwork_t		*dfw;
	stnode_t		*st;
	gboolean		err;
};

/* Q: Where are sttype_range_drange() and sttype_range_entity() defined?
 *
 * A: Those functions are defined by macros in epan/dfilter/sttype-range.h
 *
 *    The macro which creates them, STTYPE_ACCESSOR, is defined in
 *    epan/dfilter/syntax-tree.h.
 *
 * From http://www.wireshark.org/lists/ethereal-dev/200308/msg00070.html
 */

static void
check_drange_node_sanity(gpointer data, gpointer user_data)
{
	drange_node*		drnode = (drange_node*)data;
	struct check_drange_sanity_args *args = (struct check_drange_sanity_args*)user_data;
	gint			start_offset, end_offset, length;
	stnode_t                *entity;
	header_field_info	*hfinfo;

	switch (drange_node_get_ending(drnode)) {

	case DRANGE_NODE_END_T_LENGTH:
		length = drange_node_get_length(drnode);
		if (length <= 0) {
			if (!args->err) {
				args->err = TRUE;
				start_offset = drange_node_get_start_offset(drnode);
				entity = sttype_range_entity(args->st);
				if (entity && stnode_type_id(entity) == STTYPE_FIELD) {
					hfinfo = (header_field_info *)stnode_data(entity);

					dfilter_fail(args->dfw, "Range %d:%d specified for \"%s\" isn't valid, "
						"as length %d isn't positive",
						start_offset, length,
						hfinfo->abbrev,
						length);
				} else
					dfilter_fail(args->dfw, "Range %d:%d isn't valid, "
						"as length %d isn't positive",
						start_offset, length,
						length);
			}
		}
		break;

	case DRANGE_NODE_END_T_OFFSET:
		/*
		 * Make sure the start offset isn't beyond the end
		 * offset.  This applies to negative offsets too.
		 */

		/* XXX - [-ve - +ve] is probably pathological, but isn't
		 * disallowed.
		 * [+ve - -ve] is probably pathological too, and happens to be
		 * disallowed.
		 */
		start_offset = drange_node_get_start_offset(drnode);
		end_offset = drange_node_get_end_offset(drnode);
		if (start_offset > end_offset) {
			if (!args->err) {
				args->err = TRUE;
				entity = sttype_range_entity(args->st);
				if (entity && stnode_type_id(entity) == STTYPE_FIELD) {
					hfinfo = (header_field_info *)stnode_data(entity);

					dfilter_fail(args->dfw, "Range %d-%d specified for \"%s\" isn't valid, "
						"as %d is greater than %d",
						start_offset, end_offset,
						hfinfo->abbrev,
						start_offset, end_offset);

				} else
					dfilter_fail(args->dfw, "Range %d-%d isn't valid, "
						"as %d is greater than %d",
						start_offset, end_offset,
						start_offset, end_offset);
			}
		}
		break;

	case DRANGE_NODE_END_T_TO_THE_END:
		break;

	case DRANGE_NODE_END_T_UNINITIALIZED:
	default:
		g_assert_not_reached();
	}
}

static void
check_drange_sanity(dfwork_t *dfw, stnode_t *st)
{
	struct check_drange_sanity_args	args;

	args.dfw = dfw;
	args.st = st;
	args.err = FALSE;

	drange_foreach_drange_node(sttype_range_drange(st),
	    check_drange_node_sanity, &args);

	if (args.err) {
		THROW(TypeError);
	}
}

static stnode_t *
convert_to_bytes(stnode_t *arg)
{
	stnode_t      *new_st;
	drange_node   *rn;

	new_st = stnode_new(STTYPE_RANGE, NULL);

	rn = drange_node_new();
	drange_node_set_start_offset(rn, 0);
	drange_node_set_to_the_end(rn);
	/* new_st is owner of arg in this step */
	sttype_range_set1(new_st, arg, rn);

	return new_st;
}

static void
check_function(dfwork_t *dfw, stnode_t *st_node)
{
	df_func_def_t *funcdef;
	GSList        *params;
	guint          iparam;
	guint          nparams;

	funcdef  = sttype_function_funcdef(st_node);
	params   = sttype_function_params(st_node);
	nparams  = g_slist_length(params);

	if (nparams < funcdef->min_nargs) {
		dfilter_fail(dfw, "Function %s needs at least %u arguments.",
			funcdef->name, funcdef->min_nargs);
		THROW(TypeError);
	} else if (nparams > funcdef->max_nargs) {
		dfilter_fail(dfw, "Function %s can only accept %u arguments.",
			funcdef->name, funcdef->max_nargs);
		THROW(TypeError);
	}

	iparam = 0;
	while (params) {
		params->data = check_param_entity(dfw, (stnode_t *)params->data);
		funcdef->semcheck_param_function(dfw, iparam, (stnode_t *)params->data);
		params = params->next;
		iparam++;
	}
}

/* Convert a character constant to a 1-byte BYTE_STRING containing the
 * character. */
static fvalue_t *
charconst_to_bytes(dfwork_t *dfw, char *s, gboolean allow_partial_value)
{
	fvalue_t *fvalue;

	fvalue = dfilter_fvalue_from_unparsed(dfw, FT_CHAR, s, allow_partial_value);
	if (fvalue) {
		char *temp_string;
		/* It's valid. Create a 1-byte BYTE_STRING from its value. */
		temp_string = g_strdup_printf("%02x", fvalue->value.uinteger);
		FVALUE_FREE(fvalue);
		fvalue = dfilter_fvalue_from_unparsed(dfw, FT_BYTES, temp_string, allow_partial_value);
		g_free(temp_string);
	}
	return (fvalue);
}

/* If the LHS of a relation test is a FIELD, run some checks
 * and possibly some modifications of syntax tree nodes. */
static void
check_relation_LHS_FIELD(dfwork_t *dfw, const char *relation_string,
		FtypeCanFunc can_func, gboolean allow_partial_value,
		stnode_t *st_node, stnode_t *st_arg1, stnode_t *st_arg2)
{
	stnode_t		*new_st;
	sttype_id_t		type2;
	header_field_info	*hfinfo1, *hfinfo2;
	df_func_def_t		*funcdef;
	ftenum_t		ftype1, ftype2;
	fvalue_t		*fvalue;
	char			*s;

	type2 = stnode_type_id(st_arg2);

	hfinfo1 = (header_field_info*)stnode_data(st_arg1);
	ftype1 = hfinfo1->type;

	if (stnode_type_id(st_node) == STTYPE_TEST) {
		DebugLog(("    5 check_relation_LHS_FIELD(%s)\n", relation_string));
	} else {
		DebugLog(("     6 check_relation_LHS_FIELD(%s)\n", relation_string));
	}

	if (!can_func(ftype1)) {
		dfilter_fail(dfw, "%s (type=%s) cannot participate in '%s' comparison.",
				hfinfo1->abbrev, ftype_pretty_name(ftype1),
				relation_string);
		THROW(TypeError);
	}

	if (type2 == STTYPE_FIELD) {
		hfinfo2 = (header_field_info*)stnode_data(st_arg2);
		ftype2 = hfinfo2->type;

		if (!compatible_ftypes(ftype1, ftype2)) {
			dfilter_fail(dfw, "%s and %s are not of compatible types.",
					hfinfo1->abbrev, hfinfo2->abbrev);
			THROW(TypeError);
		}
		/* Do this check even though you'd think that if
		 * they're compatible, then can_func() would pass. */
		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "%s (type=%s) cannot participate in specified comparison.",
					hfinfo2->abbrev, ftype_pretty_name(ftype2));
			THROW(TypeError);
		}
	}
	else if (type2 == STTYPE_STRING || type2 == STTYPE_UNPARSED ||
	         type2 == STTYPE_CHARCONST) {
		s = (char *)stnode_data(st_arg2);
		if (strcmp(relation_string, "matches") == 0) {
			/* Convert to a FT_PCRE */
			if (type2 == STTYPE_STRING)
				fvalue = dfilter_fvalue_from_string(dfw, FT_PCRE, s);
			else
				fvalue = dfilter_fvalue_from_unparsed(dfw, FT_PCRE, s, FALSE);
		} else {
			/* Skip incompatible fields */
			while (hfinfo1->same_name_prev_id != -1 &&
					((type2 == STTYPE_STRING && ftype1 != FT_STRING && ftype1!= FT_STRINGZ) ||
					(type2 != STTYPE_STRING && (ftype1 == FT_STRING || ftype1== FT_STRINGZ)))) {
				hfinfo1 = proto_registrar_get_nth(hfinfo1->same_name_prev_id);
				ftype1 = hfinfo1->type;
			}

			if (type2 == STTYPE_STRING)
				fvalue = dfilter_fvalue_from_string(dfw, ftype1, s);
			else if (type2 == STTYPE_CHARCONST &&
			    strcmp(relation_string, "contains") == 0) {
				/* The RHS should be FT_BYTES, but a character
				 * is just a one-byte byte string. */
				fvalue = charconst_to_bytes(dfw, s, allow_partial_value);
			} else
				fvalue = dfilter_fvalue_from_unparsed(dfw, ftype1, s, allow_partial_value);

			/*
			 * If this is a character constant, just report the
			 * error, don't try to treat it as a string from
			 * a value_string table.
			 */
			if (!fvalue && type2 != STTYPE_CHARCONST) {
				/* check value_string */
				fvalue = mk_fvalue_from_val_string(dfw, hfinfo1, s);

				/*
				 * Ignore previous errors if this can be mapped
				 * to an item from value_string.
				 */
				if (fvalue && dfw->error_message) {
					g_free(dfw->error_message);
					dfw->error_message = NULL;
				}
			}
		}

		if (!fvalue) {
			THROW(TypeError);
		}

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		if (stnode_type_id(st_node) == STTYPE_TEST) {
			sttype_test_set2_args(st_node, st_arg1, new_st);
		} else {
			/* Replace STTYPE_UNPARSED element by resolved value. */
			sttype_set_replace_element(st_node, st_arg2, new_st);
		}
		stnode_free(st_arg2);
	}
	else if (type2 == STTYPE_RANGE) {
		check_drange_sanity(dfw, st_arg2);
		if (!is_bytes_type(ftype1)) {
			if (!ftype_can_slice(ftype1)) {
				dfilter_fail(dfw, "\"%s\" is a %s and cannot be converted into a sequence of bytes.",
						hfinfo1->abbrev,
						ftype_pretty_name(ftype1));
				THROW(TypeError);
			}

			/* Convert entire field to bytes */
			new_st = convert_to_bytes(st_arg1);

			sttype_test_set2_args(st_node, new_st, st_arg2);
		}
	}
	else if (type2 == STTYPE_FUNCTION) {
		funcdef = sttype_function_funcdef(st_arg2);
		ftype2 = funcdef->retval_ftype;

		if (!compatible_ftypes(ftype1, ftype2)) {
			dfilter_fail(dfw, "%s (type=%s) and return value of %s() (type=%s) are not of compatible types.",
					hfinfo1->abbrev, ftype_pretty_name(ftype1),
					funcdef->name, ftype_pretty_name(ftype2));
			THROW(TypeError);
		}

		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "return value of %s() (type=%s) cannot participate in specified comparison.",
					funcdef->name, ftype_pretty_name(ftype2));
			THROW(TypeError);
		}

		check_function(dfw, st_arg2);
	}
	else if (type2 == STTYPE_SET) {
		GSList *nodelist;
		/* A set should only ever appear on RHS of 'in' operation */
		if (strcmp(relation_string, "in") != 0) {
			g_assert_not_reached();
		}
		/* Attempt to interpret one element of the set at a time. Each
		 * element is represented by two items in the list, the element
		 * value and NULL. Both will be replaced by a lower and upper
		 * value if the element is a range. */
		nodelist = (GSList*)stnode_data(st_arg2);
		while (nodelist) {
			stnode_t *node = (stnode_t*)nodelist->data;
			/* Don't let a range on the RHS affect the LHS field. */
			if (stnode_type_id(node) == STTYPE_RANGE) {
				dfilter_fail(dfw, "A range may not appear inside a set.");
				THROW(TypeError);
				break;
			}

			nodelist = g_slist_next(nodelist);
			g_assert(nodelist);
			stnode_t *node_right = (stnode_t *)nodelist->data;
			if (node_right) {
				/* range type, check if comparison is possible. */
				if (!ftype_can_ge(ftype1)) {
					dfilter_fail(dfw, "%s (type=%s) cannot participate in '%s' comparison.",
							hfinfo1->abbrev, ftype_pretty_name(ftype1),
							">=");
					THROW(TypeError);
				}
				check_relation_LHS_FIELD(dfw, ">=", ftype_can_ge,
						allow_partial_value, st_arg2, st_arg1, node);
				check_relation_LHS_FIELD(dfw, "<=", ftype_can_le,
						allow_partial_value, st_arg2, st_arg1, node_right);
			} else {
				check_relation_LHS_FIELD(dfw, "==", can_func,
						allow_partial_value, st_arg2, st_arg1, node);
			}
			nodelist = g_slist_next(nodelist);
		}
	}
	else {
		g_assert_not_reached();
	}
}

static void
check_relation_LHS_STRING(dfwork_t *dfw, const char* relation_string,
		FtypeCanFunc can_func, gboolean allow_partial_value _U_,
		stnode_t *st_node,
		stnode_t *st_arg1, stnode_t *st_arg2)
{
	stnode_t		*new_st;
	sttype_id_t		type2;
	header_field_info	*hfinfo2;
	df_func_def_t		*funcdef;
	ftenum_t		ftype2;
	fvalue_t		*fvalue;
	char			*s;

	type2 = stnode_type_id(st_arg2);

	DebugLog(("    5 check_relation_LHS_STRING()\n"));

	if (type2 == STTYPE_FIELD) {
		hfinfo2 = (header_field_info*)stnode_data(st_arg2);
		ftype2 = hfinfo2->type;

		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "%s (type=%s) cannot participate in '%s' comparison.",
					hfinfo2->abbrev, ftype_pretty_name(ftype2),
					relation_string);
			THROW(TypeError);
		}

		s = (char*)stnode_data(st_arg1);
		fvalue = dfilter_fvalue_from_string(dfw, ftype2, s);
		if (!fvalue) {
			/* check value_string */
			fvalue = mk_fvalue_from_val_string(dfw, hfinfo2, s);
			if (!fvalue) {
				THROW(TypeError);
			}
		}

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, new_st, st_arg2);
		stnode_free(st_arg1);
	}
	else if (type2 == STTYPE_STRING || type2 == STTYPE_UNPARSED ||
	         type2 == STTYPE_CHARCONST) {
		/* Well now that's silly... */
		dfilter_fail(dfw, "Neither \"%s\" nor \"%s\" are field or protocol names.",
				(char *)stnode_data(st_arg1),
				(char *)stnode_data(st_arg2));
		THROW(TypeError);
	}
	else if (type2 == STTYPE_RANGE) {
		check_drange_sanity(dfw, st_arg2);
		s = (char*)stnode_data(st_arg1);
		fvalue = dfilter_fvalue_from_string(dfw, FT_BYTES, s);
		if (!fvalue) {
			THROW(TypeError);
		}
		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, new_st, st_arg2);
		stnode_free(st_arg1);
	}
	else if (type2 == STTYPE_FUNCTION) {
		funcdef = sttype_function_funcdef(st_arg2);
		ftype2  = funcdef->retval_ftype;

		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "Return value of function %s (type=%s) cannot participate in '%s' comparison.",
				funcdef->name, ftype_pretty_name(ftype2),
				relation_string);
			THROW(TypeError);
		}

		s = (char*)stnode_data(st_arg1);
		fvalue = dfilter_fvalue_from_string(dfw, ftype2, s);
		if (!fvalue) {
			THROW(TypeError);
		}

		check_function(dfw, st_arg2);

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, new_st, st_arg2);
		stnode_free(st_arg1);
	}
	else if (type2 == STTYPE_SET) {
		dfilter_fail(dfw, "Only a field may be tested for membership in a set.");
		THROW(TypeError);
	}
	else {
		g_assert_not_reached();
	}
}

static void
check_relation_LHS_UNPARSED(dfwork_t *dfw, const char* relation_string,
		FtypeCanFunc can_func, gboolean allow_partial_value,
		stnode_t *st_node,
		stnode_t *st_arg1, stnode_t *st_arg2)
{
	stnode_t		*new_st;
	sttype_id_t		type2;
	header_field_info	*hfinfo2;
	df_func_def_t		*funcdef;
	ftenum_t		ftype2;
	fvalue_t		*fvalue;
	char			*s;

	type2 = stnode_type_id(st_arg2);

	DebugLog(("    5 check_relation_LHS_UNPARSED()\n"));

	if (type2 == STTYPE_FIELD) {
		hfinfo2 = (header_field_info*)stnode_data(st_arg2);
		ftype2 = hfinfo2->type;

		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "%s (type=%s) cannot participate in '%s' comparison.",
					hfinfo2->abbrev, ftype_pretty_name(ftype2),
					relation_string);
			THROW(TypeError);
		}

		s = (char*)stnode_data(st_arg1);
		fvalue = dfilter_fvalue_from_unparsed(dfw, ftype2, s, allow_partial_value);
		if (!fvalue) {
			/* check value_string */
			fvalue = mk_fvalue_from_val_string(dfw, hfinfo2, s);
			if (!fvalue) {
				THROW(TypeError);
			}
		}

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, new_st, st_arg2);
		stnode_free(st_arg1);
	}
	else if (type2 == STTYPE_STRING || type2 == STTYPE_UNPARSED ||
	         type2 == STTYPE_CHARCONST) {
		/* Well now that's silly... */
		dfilter_fail(dfw, "Neither \"%s\" nor \"%s\" are field or protocol names.",
				(char *)stnode_data(st_arg1),
				(char *)stnode_data(st_arg2));
		THROW(TypeError);
	}
	else if (type2 == STTYPE_RANGE) {
		check_drange_sanity(dfw, st_arg2);
		s = (char*)stnode_data(st_arg1);
		fvalue = dfilter_fvalue_from_unparsed(dfw, FT_BYTES, s, allow_partial_value);
		if (!fvalue) {
			THROW(TypeError);
		}
		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, new_st, st_arg2);
		stnode_free(st_arg1);
	}
	else if (type2 == STTYPE_FUNCTION) {
		funcdef = sttype_function_funcdef(st_arg2);
		ftype2  = funcdef->retval_ftype;

		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "return value of function %s() (type=%s) cannot participate in '%s' comparison.",
					funcdef->name, ftype_pretty_name(ftype2), relation_string);
			THROW(TypeError);
		}

		s =  (char*)stnode_data(st_arg1);
		fvalue = dfilter_fvalue_from_unparsed(dfw, ftype2, s, allow_partial_value);

		if (!fvalue) {
			THROW(TypeError);
		}

		check_function(dfw, st_arg2);

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, new_st, st_arg2);
		stnode_free(st_arg1);
	}
	else if (type2 == STTYPE_SET) {
		dfilter_fail(dfw, "Only a field may be tested for membership in a set.");
		THROW(TypeError);
	}
	else {
		g_assert_not_reached();
	}
}

static void
check_relation_LHS_RANGE(dfwork_t *dfw, const char *relation_string,
		FtypeCanFunc can_func _U_,
		gboolean allow_partial_value,
		stnode_t *st_node,
		stnode_t *st_arg1, stnode_t *st_arg2)
{
	stnode_t		*new_st;
	sttype_id_t		type2;
	stnode_t		*entity1;
	header_field_info	*hfinfo1, *hfinfo2;
	ftenum_t		ftype1, ftype2;
	fvalue_t		*fvalue;
	char			*s;
	int                     len_range;

	DebugLog(("    5 check_relation_LHS_RANGE(%s)\n", relation_string));

	type2 = stnode_type_id(st_arg2);
	entity1 = sttype_range_entity(st_arg1);
	if (entity1 && stnode_type_id(entity1) == STTYPE_FIELD) {
		hfinfo1 = (header_field_info *)stnode_data(entity1);
		ftype1 = hfinfo1->type;

		if (!ftype_can_slice(ftype1)) {
			dfilter_fail(dfw, "\"%s\" is a %s and cannot be sliced into a sequence of bytes.",
					hfinfo1->abbrev, ftype_pretty_name(ftype1));
			THROW(TypeError);
		}
	} else if (entity1 && stnode_type_id(entity1) == STTYPE_FUNCTION) {
		df_func_def_t *funcdef = sttype_function_funcdef(entity1);
		ftype1 = funcdef->retval_ftype;

		if (!ftype_can_slice(ftype1)) {
			dfilter_fail(dfw, "Return value of function \"%s\" is a %s and cannot be converted into a sequence of bytes.",
					funcdef->name, ftype_pretty_name(ftype1));
			THROW(TypeError);
		}

		check_function(dfw, entity1);

	} else {
		if (entity1 == NULL) {
			dfilter_fail(dfw, "Range is not supported, details: " G_STRLOC " entity: NULL");
		} else {
			dfilter_fail(dfw, "Range is not supported, details: " G_STRLOC " entity: %p of type %d",
					(void *)entity1, stnode_type_id(entity1));
		}
		THROW(TypeError);
	}

	check_drange_sanity(dfw, st_arg1);

	if (type2 == STTYPE_FIELD) {
		DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_FIELD)\n"));
		hfinfo2 = (header_field_info*)stnode_data(st_arg2);
		ftype2 = hfinfo2->type;

		if (!is_bytes_type(ftype2)) {
			if (!ftype_can_slice(ftype2)) {
				dfilter_fail(dfw, "\"%s\" is a %s and cannot be converted into a sequence of bytes.",
						hfinfo2->abbrev,
						ftype_pretty_name(ftype2));
				THROW(TypeError);
			}

			/* Convert entire field to bytes */
			new_st = convert_to_bytes(st_arg2);

			sttype_test_set2_args(st_node, st_arg1, new_st);
		}
	}
	else if (type2 == STTYPE_STRING) {
		DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_STRING)\n"));
		s = (char*)stnode_data(st_arg2);
		if (strcmp(relation_string, "matches") == 0) {
			/* Convert to a FT_PCRE */
			fvalue = dfilter_fvalue_from_string(dfw, FT_PCRE, s);
		} else {
			fvalue = dfilter_fvalue_from_string(dfw, FT_BYTES, s);
		}
		if (!fvalue) {
			DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_STRING): Could not convert from string!\n"));
			THROW(TypeError);
		}
		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, st_arg1, new_st);
		stnode_free(st_arg2);
	}
	else if (type2 == STTYPE_UNPARSED) {
		DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_UNPARSED)\n"));
		s = (char*)stnode_data(st_arg2);
		len_range = drange_get_total_length(sttype_range_drange(st_arg1));
		if (strcmp(relation_string, "matches") == 0) {
			/* Convert to a FT_PCRE */
			fvalue = dfilter_fvalue_from_unparsed(dfw, FT_PCRE, s, FALSE);
		}

		/* The RHS should be FT_BYTES. However, there is a special case where
		 * the range slice on the LHS is one byte long. In that case, it is natural
		 * for the user to specify a normal hex integer on the RHS, with the "0x"
		 * notation, as in "slice[0] == 0x10". We can't allow this for any
		 * slices that are longer than one byte, because then we'd have to know
		 * which endianness the byte string should be in. */
		else if (len_range == 1 && strlen(s) == 4 && strncmp(s, "0x", 2) == 0) {
		    /* Even if the RHS string starts with "0x", it still could fail to
		     * be an integer.  Try converting it here. */
		    fvalue = dfilter_fvalue_from_unparsed(dfw, FT_UINT8, s, allow_partial_value);
		    if (fvalue) {
			FVALUE_FREE(fvalue);
			/* The value doees indeed fit into 8 bits. Create a BYTE_STRING
			 * from it. Since we know that the last 2 characters are a valid
			 * hex string, just use those directly. */
			fvalue = dfilter_fvalue_from_unparsed(dfw, FT_BYTES, s+2, allow_partial_value);
		    }
		}
		else {
		    fvalue = dfilter_fvalue_from_unparsed(dfw, FT_BYTES, s, allow_partial_value);
		}
		if (!fvalue) {
			DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_UNPARSED): Could not convert from string!\n"));
			THROW(TypeError);
		}
		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, st_arg1, new_st);
		stnode_free(st_arg2);
	}
	else if (type2 == STTYPE_CHARCONST) {
		DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_CHARCONST)\n"));
		s = (char*)stnode_data(st_arg2);
		if (strcmp(relation_string, "matches") == 0) {
			/* Convert to a FT_PCRE */
			fvalue = dfilter_fvalue_from_unparsed(dfw, FT_PCRE, s, FALSE);
		} else {
			/* The RHS should be FT_BYTES, but a character is just a
			 * one-byte byte string. */
			fvalue = charconst_to_bytes(dfw, s, allow_partial_value);
		}
		if (!fvalue) {
			DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_UNPARSED): Could not convert from string!\n"));
			THROW(TypeError);
		}
		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, st_arg1, new_st);
		stnode_free(st_arg2);
	}
	else if (type2 == STTYPE_RANGE) {
		DebugLog(("    5 check_relation_LHS_RANGE(type2 = STTYPE_RANGE)\n"));
		check_drange_sanity(dfw, st_arg2);
	}
	else if (type2 == STTYPE_FUNCTION) {
		df_func_def_t *funcdef = sttype_function_funcdef(st_arg2);
		ftype2  = funcdef->retval_ftype;

		if (!is_bytes_type(ftype2)) {
			if (!ftype_can_slice(ftype2)) {
				dfilter_fail(dfw, "Return value of function \"%s\" is a %s and cannot be converted into a sequence of bytes.",
					funcdef->name,
					ftype_pretty_name(ftype2));
				THROW(TypeError);
			}

			/* Convert function result to bytes */
			new_st = convert_to_bytes(st_arg2);

			sttype_test_set2_args(st_node, st_arg1, new_st);
		}

		check_function(dfw, st_arg2);
	}
	else if (type2 == STTYPE_SET) {
		dfilter_fail(dfw, "Only a field may be tested for membership in a set.");
		THROW(TypeError);
	}
	else {
		g_assert_not_reached();
	}
}

static stnode_t*
check_param_entity(dfwork_t *dfw, stnode_t *st_node)
{
	sttype_id_t		e_type;
	stnode_t		*new_st;
	fvalue_t		*fvalue;
	char *s;

	e_type = stnode_type_id(st_node);
	/* If there's an unparsed string, change it to an FT_STRING */
	if (e_type == STTYPE_UNPARSED || e_type == STTYPE_CHARCONST) {
		s = (char*)stnode_data(st_node);
		fvalue = dfilter_fvalue_from_unparsed(dfw, FT_STRING, s, FALSE);
		if (!fvalue) {
			THROW(TypeError);
		}

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		stnode_free(st_node);
		return new_st;
	}
	return st_node;
}


/* If the LHS of a relation test is a FUNCTION, run some checks
 * and possibly some modifications of syntax tree nodes. */
static void
check_relation_LHS_FUNCTION(dfwork_t *dfw, const char *relation_string,
		FtypeCanFunc can_func,
		gboolean allow_partial_value,
		stnode_t *st_node, stnode_t *st_arg1, stnode_t *st_arg2)
{
	stnode_t		*new_st;
	sttype_id_t		type2;
	header_field_info	*hfinfo2;
	ftenum_t		ftype1, ftype2;
	fvalue_t		*fvalue;
	char			*s;
	df_func_def_t   *funcdef;
	df_func_def_t   *funcdef2;
	/* GSList          *params; */

	check_function(dfw, st_arg1);
	type2 = stnode_type_id(st_arg2);

	funcdef = sttype_function_funcdef(st_arg1);
	ftype1 = funcdef->retval_ftype;

	/* params = */sttype_function_params(st_arg1);  /* XXX: is this done for the side-effect ? */

	DebugLog(("    5 check_relation_LHS_FUNCTION(%s)\n", relation_string));

	if (!can_func(ftype1)) {
		dfilter_fail(dfw, "Function %s (type=%s) cannot participate in '%s' comparison.",
				funcdef->name, ftype_pretty_name(ftype1),
				relation_string);
		THROW(TypeError);
	}

	if (type2 == STTYPE_FIELD) {
		hfinfo2 = (header_field_info*)stnode_data(st_arg2);
		ftype2 = hfinfo2->type;

		if (!compatible_ftypes(ftype1, ftype2)) {
			dfilter_fail(dfw, "Function %s and %s are not of compatible types.",
					funcdef->name, hfinfo2->abbrev);
			THROW(TypeError);
		}
		/* Do this check even though you'd think that if
		 * they're compatible, then can_func() would pass. */
		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "%s (type=%s) cannot participate in specified comparison.",
					hfinfo2->abbrev, ftype_pretty_name(ftype2));
			THROW(TypeError);
		}
	}
	else if (type2 == STTYPE_STRING) {
		s = (char*)stnode_data(st_arg2);
		if (strcmp(relation_string, "matches") == 0) {
			/* Convert to a FT_PCRE */
			fvalue = dfilter_fvalue_from_string(dfw, FT_PCRE, s);
		} else {
			fvalue = dfilter_fvalue_from_string(dfw, ftype1, s);
		}
		if (!fvalue) {
			THROW(TypeError);
		}

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, st_arg1, new_st);
		stnode_free(st_arg2);
	}
	else if (type2 == STTYPE_UNPARSED || type2 == STTYPE_CHARCONST) {
		s = (char*)stnode_data(st_arg2);
		if (strcmp(relation_string, "matches") == 0) {
			/* Convert to a FT_PCRE */
			fvalue = dfilter_fvalue_from_unparsed(dfw, FT_PCRE, s, FALSE);
		} else {
			fvalue = dfilter_fvalue_from_unparsed(dfw, ftype1, s, allow_partial_value);
		}
		if (!fvalue) {
			THROW(TypeError);
		}

		new_st = stnode_new(STTYPE_FVALUE, fvalue);
		sttype_test_set2_args(st_node, st_arg1, new_st);
		stnode_free(st_arg2);
	}
	else if (type2 == STTYPE_RANGE) {
		check_drange_sanity(dfw, st_arg2);
		if (!is_bytes_type(ftype1)) {
			if (!ftype_can_slice(ftype1)) {
				dfilter_fail(dfw, "Function \"%s\" is a %s and cannot be converted into a sequence of bytes.",
						funcdef->name,
						ftype_pretty_name(ftype1));
				THROW(TypeError);
			}

			/* Convert function result to bytes */
			new_st = convert_to_bytes(st_arg1);

			sttype_test_set2_args(st_node, new_st, st_arg2);
		}
	}
	else if (type2 == STTYPE_FUNCTION) {
		funcdef2 = sttype_function_funcdef(st_arg2);
		ftype2 = funcdef2->retval_ftype;

		if (!compatible_ftypes(ftype1, ftype2)) {
			dfilter_fail(dfw, "Return values of function %s (type=%s) and function %s (type=%s) are not of compatible types.",
				     funcdef->name, ftype_pretty_name(ftype1), funcdef2->name, ftype_pretty_name(ftype2));
			THROW(TypeError);
		}

		/* Do this check even though you'd think that if
		 * they're compatible, then can_func() would pass. */
		if (!can_func(ftype2)) {
			dfilter_fail(dfw, "Return value of %s (type=%s) cannot participate in specified comparison.",
				     funcdef2->name, ftype_pretty_name(ftype2));
			THROW(TypeError);
		}

		check_function(dfw, st_arg2);
	}
	else if (type2 == STTYPE_SET) {
		dfilter_fail(dfw, "Only a field may be tested for membership in a set.");
		THROW(TypeError);
	}
	else {
		g_assert_not_reached();
	}
}


/* Check the semantics of any relational test. */
static void
check_relation(dfwork_t *dfw, const char *relation_string,
		gboolean allow_partial_value,
		FtypeCanFunc can_func, stnode_t *st_node,
		stnode_t *st_arg1, stnode_t *st_arg2)
{
#ifdef DEBUG_dfilter
	static guint i = 0;
#endif
header_field_info   *hfinfo;

	DebugLog(("   4 check_relation(\"%s\") [%u]\n", relation_string, i++));

	/* Protocol can only be on LHS (for "contains" or "matches" operators).
	 * Check to see if protocol is on RHS.  This catches the case where the
	 * user has written "fc" on the RHS, probably intending a byte value
	 * rather than the fibre channel protocol.
	 */

	if (stnode_type_id(st_arg2) == STTYPE_FIELD) {
		hfinfo = (header_field_info*)stnode_data(st_arg2);
		if (hfinfo->type == FT_PROTOCOL) {
			dfilter_fail(dfw, "Protocol (\"%s\") cannot appear on right-hand side of comparison.", hfinfo->abbrev);
			THROW(TypeError);
		}
	}

	switch (stnode_type_id(st_arg1)) {
		case STTYPE_FIELD:
			check_relation_LHS_FIELD(dfw, relation_string, can_func,
					allow_partial_value, st_node, st_arg1, st_arg2);
			break;
		case STTYPE_STRING:
			check_relation_LHS_STRING(dfw, relation_string, can_func,
					allow_partial_value, st_node, st_arg1, st_arg2);
			break;
		case STTYPE_RANGE:
			check_relation_LHS_RANGE(dfw, relation_string, can_func,
					allow_partial_value, st_node, st_arg1, st_arg2);
			break;
		case STTYPE_UNPARSED:
		case STTYPE_CHARCONST:
			check_relation_LHS_UNPARSED(dfw, relation_string, can_func,
					allow_partial_value, st_node, st_arg1, st_arg2);
			break;
		case STTYPE_FUNCTION:
			check_relation_LHS_FUNCTION(dfw, relation_string, can_func,
					allow_partial_value, st_node, st_arg1, st_arg2);
			break;

		case STTYPE_UNINITIALIZED:
		case STTYPE_TEST:
		case STTYPE_INTEGER:
		case STTYPE_FVALUE:
		case STTYPE_SET:
		default:
			g_assert_not_reached();
	}
}

/* Check the semantics of any type of TEST */
static void
check_test(dfwork_t *dfw, stnode_t *st_node, GPtrArray *deprecated)
{
	test_op_t		st_op, st_arg_op;
	stnode_t		*st_arg1, *st_arg2;
#ifdef DEBUG_dfilter
	static guint i = 0;
#endif

	DebugLog(("  3 check_test(stnode_t *st_node = %p) [%u]\n", st_node, i));

	sttype_test_get(st_node, &st_op, &st_arg1, &st_arg2);

	switch (st_op) {
		case TEST_OP_UNINITIALIZED:
			g_assert_not_reached();
			break;

		case TEST_OP_EXISTS:
			check_exists(dfw, st_arg1);
			break;

		case TEST_OP_NOT:
			semcheck(dfw, st_arg1, deprecated);
			break;

		case TEST_OP_AND:
		case TEST_OP_OR:
			if (stnode_type_id(st_arg1) == STTYPE_TEST) {
				sttype_test_get(st_arg1, &st_arg_op, NULL, NULL);
				if (st_arg_op == TEST_OP_AND || st_arg_op == TEST_OP_OR) {
					if (st_op != st_arg_op && !st_arg1->inside_brackets)
						g_ptr_array_add(deprecated, g_strdup("suggest parentheses around '&&' within '||'"));
				}
			}

			if (stnode_type_id(st_arg2) == STTYPE_TEST) {
				sttype_test_get(st_arg2, &st_arg_op, NULL, NULL);
				if (st_arg_op == TEST_OP_AND || st_arg_op == TEST_OP_OR) {
					if (st_op != st_arg_op && !st_arg2->inside_brackets)
						g_ptr_array_add(deprecated, g_strdup("suggest parentheses around '&&' within '||'"));
				}
			}

			semcheck(dfw, st_arg1, deprecated);
			semcheck(dfw, st_arg2, deprecated);
			break;

		case TEST_OP_EQ:
			check_relation(dfw, "==", FALSE, ftype_can_eq, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_NE:
			check_relation(dfw, "!=", FALSE, ftype_can_ne, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_GT:
			check_relation(dfw, ">", FALSE, ftype_can_gt, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_GE:
			check_relation(dfw, ">=", FALSE, ftype_can_ge, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_LT:
			check_relation(dfw, "<", FALSE, ftype_can_lt, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_LE:
			check_relation(dfw, "<=", FALSE, ftype_can_le, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_BITWISE_AND:
			check_relation(dfw, "&", FALSE, ftype_can_bitwise_and, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_CONTAINS:
			check_relation(dfw, "contains", TRUE, ftype_can_contains, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_MATCHES:
			check_relation(dfw, "matches", TRUE, ftype_can_matches, st_node, st_arg1, st_arg2);
			break;
		case TEST_OP_IN:
			/* Use the ftype_can_eq as the items in the set are evaluated using the
			 * semantics of equality. */
			check_relation(dfw, "in", FALSE, ftype_can_eq, st_node, st_arg1, st_arg2);
			break;

		default:
			g_assert_not_reached();
	}
	DebugLog(("  3 check_test(stnode_t *st_node = %p) [%u] - End\n", st_node, i++));
}


/* Check the entire syntax tree. */
static void
semcheck(dfwork_t *dfw, stnode_t *st_node, GPtrArray *deprecated)
{
#ifdef DEBUG_dfilter
	static guint i = 0;
#endif
	DebugLog((" 2 semcheck(stnode_t *st_node = %p) [%u]\n", st_node, i++));
	/* The parser assures that the top-most syntax-tree
	 * node will be a TEST node, no matter what. So assert that. */
	switch (stnode_type_id(st_node)) {
		case STTYPE_TEST:
			check_test(dfw, st_node, deprecated);
			break;
		default:
			g_assert_not_reached();
	}
}


/* Check the syntax tree for semantic errors, and convert
 * some of the nodes into the form they need to be in order to
 * later generate the DFVM bytecode. */
gboolean
dfw_semcheck(dfwork_t *dfw, GPtrArray *deprecated)
{
	volatile gboolean ok_filter = TRUE;
#ifdef DEBUG_dfilter
	static guint i = 0;
#endif

	DebugLog(("1 dfw_semcheck(dfwork_t *dfw = %p) [%u]\n", dfw, i));
	/* Instead of having to check for errors at every stage of
	 * the semantic-checking, the semantic-checking code will
	 * throw an exception if a problem is found. */
	TRY {
		semcheck(dfw, dfw->st_root, deprecated);
	}
	CATCH(TypeError) {
		ok_filter = FALSE;
	}
	ENDTRY;

	DebugLog(("1 dfw_semcheck(dfwork_t *dfw = %p) [%u] - Returns %d\n",
				dfw, i++,ok_filter));
	return ok_filter;
}

/*
 * Editor modelines  -  http://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:
 */