Adding upstream version 4.2.2.upstream/4.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 756 insertions, 0 deletions

diff --git a/epan/expert.c b/epan/expert.c
new file mode 100644
index 00000000..a4ea386e
--- /dev/null
+++ b/epan/expert.c
@@ -0,0 +1,756 @@
+/* expert.c
+ * Collecting Expert information.
+ *
+ * Implemented as a tap named "expert".
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+#define WS_LOG_DOMAIN LOG_DOMAIN_EPAN
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "packet.h"
+#include "expert.h"
+#include "uat.h"
+#include "prefs.h"
+#include <epan/prefs-int.h>
+#include <epan/wmem_scopes.h>
+#include "tap.h"
+
+#include <wsutil/str_util.h>
+#include <wsutil/wslog.h>
+
+/* proto_expert cannot be static because it's referenced in the
+ * print routines
+ */
+int proto_expert              = -1;
+
+static int proto_malformed    = -1;
+
+static int expert_tap         = -1;
+static int highest_severity   =  0;
+
+static int ett_expert         = -1;
+static int ett_subexpert      = -1;
+
+static int hf_expert_msg      = -1;
+static int hf_expert_group    = -1;
+static int hf_expert_severity = -1;
+
+struct expert_module
+{
+	const char *proto_name;
+	int         proto_id;      /* Cache this for registering hfs */
+};
+
+/* List which stores protocols and expert_info that have been registered */
+typedef struct _gpa_expertinfo_t {
+	guint32             len;
+	guint32             allocated_len;
+	expert_field_info **ei;
+} gpa_expertinfo_t;
+static gpa_expertinfo_t gpa_expertinfo;
+
+/* Hash table of abbreviations and IDs */
+static GHashTable *gpa_name_map = NULL;
+
+/* Deregistered expert infos */
+static GPtrArray *deregistered_expertinfos = NULL;
+
+const value_string expert_group_vals[] = {
+	{ PI_CHECKSUM,          "Checksum" },
+	{ PI_SEQUENCE,          "Sequence" },
+	{ PI_RESPONSE_CODE,     "Response" },
+	{ PI_REQUEST_CODE,      "Request" },
+	{ PI_UNDECODED,         "Undecoded" },
+	{ PI_REASSEMBLE,        "Reassemble" },
+	{ PI_MALFORMED,         "Malformed" },
+	{ PI_DEBUG,             "Debug" },
+	{ PI_PROTOCOL,          "Protocol" },
+	{ PI_SECURITY,          "Security" },
+	{ PI_COMMENTS_GROUP,    "Comment" },
+	{ PI_DECRYPTION,        "Decryption" },
+	{ PI_ASSUMPTION,        "Assumption" },
+	{ PI_DEPRECATED,        "Deprecated" },
+	{ 0, NULL }
+};
+
+const value_string expert_severity_vals[] = {
+	{ PI_ERROR,             "Error" },
+	{ PI_WARN,              "Warning" },
+	{ PI_NOTE,              "Note" },
+	{ PI_CHAT,              "Chat" },
+	{ PI_COMMENT,           "Comment" },
+	{ 0, NULL }
+};
+
+/* Possible values for a checksum evaluation */
+const value_string expert_checksum_vals[] = {
+	{ EXPERT_CHECKSUM_DISABLED,   "Disabled"  },
+	{ EXPERT_CHECKSUM_UNKNOWN,    "Unknown"  },
+	{ EXPERT_CHECKSUM_GOOD,       "Good"  },
+	{ EXPERT_CHECKSUM_BAD,        "Bad" },
+	{ 0,        NULL }
+};
+
+static expert_field_info *expert_registrar_get_byname(const char *field_name);
+
+/*----------------------------------------------------------------------------*/
+/* UAT for customizing severity levels.                                       */
+/*----------------------------------------------------------------------------*/
+typedef struct
+{
+	char    *field;
+	guint32  severity;
+} expert_level_entry_t;
+
+static expert_level_entry_t *uat_expert_entries = NULL;
+static guint expert_level_entry_count = 0;
+/* Array of field names currently in UAT */
+static GArray *uat_saved_fields = NULL;
+
+UAT_CSTRING_CB_DEF(uat_expert_entries, field, expert_level_entry_t)
+UAT_VS_DEF(uat_expert_entries, severity, expert_level_entry_t, guint32, PI_ERROR, "Error")
+
+static bool uat_expert_update_cb(void *r, char **err)
+{
+	expert_level_entry_t *rec = (expert_level_entry_t *)r;
+
+	if (expert_registrar_get_byname(rec->field) == NULL) {
+		*err = ws_strdup_printf("Expert Info field doesn't exist: %s", rec->field);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+static void *uat_expert_copy_cb(void *n, const void *o, size_t siz _U_)
+{
+	expert_level_entry_t       *new_record = (expert_level_entry_t*)n;
+	const expert_level_entry_t *old_record = (const expert_level_entry_t *)o;
+
+	new_record->field = g_strdup(old_record->field);
+
+	new_record->severity = old_record->severity;
+
+	return new_record;
+}
+
+static void uat_expert_free_cb(void*r)
+{
+	expert_level_entry_t *rec = (expert_level_entry_t *)r;
+
+	g_free(rec->field);
+}
+
+static void uat_expert_post_update_cb(void)
+{
+	guint              i;
+	expert_field_info *field;
+
+	/* Reset any of the previous list of expert info fields to their original severity */
+	for ( i = 0 ; i < uat_saved_fields->len; i++ ) {
+		field = g_array_index(uat_saved_fields, expert_field_info*, i);
+		if (field != NULL) {
+			field->severity = field->orig_severity;
+		}
+	}
+
+	g_array_set_size(uat_saved_fields, 0);
+
+	for (i = 0; i < expert_level_entry_count; i++)
+	{
+		field = expert_registrar_get_byname(uat_expert_entries[i].field);
+		if (field != NULL)
+		{
+			field->severity = uat_expert_entries[i].severity;
+			g_array_append_val(uat_saved_fields, field);
+		}
+	}
+}
+
+#define EXPERT_REGISTRAR_GET_NTH(eiindex, expinfo)                                               \
+	if((guint)eiindex >= gpa_expertinfo.len && wireshark_abort_on_dissector_bug)   \
+		ws_error("Unregistered expert info! index=%d", eiindex);                          \
+	DISSECTOR_ASSERT_HINT((guint)eiindex < gpa_expertinfo.len, "Unregistered expert info!"); \
+	DISSECTOR_ASSERT_HINT(gpa_expertinfo.ei[eiindex] != NULL, "Unregistered expert info!");	\
+	expinfo = gpa_expertinfo.ei[eiindex];
+
+void
+expert_packet_init(void)
+{
+	module_t *module_expert;
+	uat_t    *expert_uat;
+
+	static hf_register_info hf[] = {
+		{ &hf_expert_msg,
+			{ "Message", "_ws.expert.message", FT_STRING, BASE_NONE, NULL, 0, "Wireshark expert information", HFILL }
+		},
+		{ &hf_expert_group,
+			{ "Group", "_ws.expert.group", FT_UINT32, BASE_NONE, VALS(expert_group_vals), 0, "Wireshark expert group", HFILL }
+		},
+		{ &hf_expert_severity,
+			{ "Severity level", "_ws.expert.severity", FT_UINT32, BASE_NONE, VALS(expert_severity_vals), 0, "Wireshark expert severity level", HFILL }
+		}
+	};
+	static gint *ett[] = {
+		&ett_expert,
+		&ett_subexpert
+	};
+
+	/* UAT for overriding severity levels */
+	static uat_field_t custom_expert_fields[] = {
+		UAT_FLD_CSTRING(uat_expert_entries, field, "Field name", "Expert Info filter name"),
+		UAT_FLD_VS(uat_expert_entries, severity, "Severity", expert_severity_vals, "Custom severity level"),
+		UAT_END_FIELDS
+	};
+
+	if (expert_tap == -1) {
+		expert_tap = register_tap("expert");
+	}
+
+	if (proto_expert == -1) {
+		proto_expert = proto_register_protocol("Expert Info", "Expert", "_ws.expert");
+		proto_register_field_array(proto_expert, hf, array_length(hf));
+		proto_register_subtree_array(ett, array_length(ett));
+		proto_set_cant_toggle(proto_expert);
+
+		module_expert = prefs_register_protocol(proto_expert, NULL);
+		//Since "expert" is really a pseudo protocol, it shouldn't be
+		//categorized with other "real" protocols when it comes to
+		//preferences.  Since it's just a UAT, don't bury it in
+		//with the other protocols
+		module_expert->use_gui = FALSE;
+
+		expert_uat = uat_new("Expert Info Severity Level Configuration",
+			sizeof(expert_level_entry_t),
+			"expert_severity",
+			TRUE,
+			(void **)&uat_expert_entries,
+			&expert_level_entry_count,
+			UAT_AFFECTS_DISSECTION,
+			NULL,
+			uat_expert_copy_cb,
+			uat_expert_update_cb,
+			uat_expert_free_cb,
+			uat_expert_post_update_cb,
+			NULL,
+			custom_expert_fields);
+
+		prefs_register_uat_preference(module_expert,
+			"expert_severity_levels",
+			"Severity Level Configuration",
+			"A table that overrides Expert Info field severity levels to user configured levels",
+			expert_uat);
+
+	}
+
+	highest_severity = 0;
+
+	proto_malformed = proto_get_id_by_filter_name("_ws.malformed");
+}
+
+void
+expert_init(void)
+{
+	gpa_expertinfo.len           = 0;
+	gpa_expertinfo.allocated_len = 0;
+	gpa_expertinfo.ei            = NULL;
+	gpa_name_map                 = g_hash_table_new_full(g_str_hash, g_str_equal, NULL, NULL);
+	uat_saved_fields             = g_array_new(FALSE, FALSE, sizeof(expert_field_info*));
+	deregistered_expertinfos     = g_ptr_array_new();
+}
+
+void
+expert_packet_cleanup(void)
+{
+}
+
+void
+expert_cleanup(void)
+{
+	if (gpa_expertinfo.allocated_len) {
+		gpa_expertinfo.len           = 0;
+		gpa_expertinfo.allocated_len = 0;
+		g_free(gpa_expertinfo.ei);
+		gpa_expertinfo.ei          = NULL;
+	}
+
+	/* Free the abbrev/ID GTree */
+	if (gpa_name_map) {
+		g_hash_table_destroy(gpa_name_map);
+		gpa_name_map = NULL;
+	}
+
+	/* Free the UAT saved fields */
+	if (uat_saved_fields) {
+		g_array_free(uat_saved_fields, TRUE);
+		uat_saved_fields = NULL;
+	}
+
+	if (deregistered_expertinfos) {
+		g_ptr_array_free(deregistered_expertinfos, TRUE);
+		deregistered_expertinfos = NULL;
+	}
+}
+
+
+int
+expert_get_highest_severity(void)
+{
+	return highest_severity;
+}
+
+void
+expert_update_comment_count(guint64 count)
+{
+	if (count==0 && highest_severity==PI_COMMENT)
+		highest_severity = 0;
+}
+
+expert_module_t *expert_register_protocol(int id)
+{
+	expert_module_t *module;
+	protocol_t      *protocol;
+
+	protocol = find_protocol_by_id(id);
+
+	module = wmem_new(wmem_epan_scope(), expert_module_t);
+	module->proto_id = id;
+	module->proto_name = proto_get_protocol_short_name(protocol);
+
+	return module;
+}
+
+void
+expert_deregister_expertinfo (const char *abbrev)
+{
+	expert_field_info *expinfo = (expert_field_info*)g_hash_table_lookup(gpa_name_map, abbrev);
+	if (expinfo) {
+		g_ptr_array_add(deregistered_expertinfos, gpa_expertinfo.ei[expinfo->id]);
+		g_hash_table_steal(gpa_name_map, abbrev);
+	}
+}
+
+void
+expert_deregister_protocol (expert_module_t *module)
+{
+	wmem_free(wmem_epan_scope(), module);
+}
+
+static void
+free_deregistered_expertinfo (gpointer data, gpointer user_data _U_)
+{
+	expert_field_info *expinfo = (expert_field_info *) data;
+	gpa_expertinfo.ei[expinfo->id] = NULL; /* Invalidate this id */
+}
+
+void
+expert_free_deregistered_expertinfos (void)
+{
+	g_ptr_array_foreach(deregistered_expertinfos, free_deregistered_expertinfo, NULL);
+	g_ptr_array_free(deregistered_expertinfos, TRUE);
+	deregistered_expertinfos = g_ptr_array_new();
+}
+
+static int
+expert_register_field_init(expert_field_info *expinfo, expert_module_t *module)
+{
+	/* Check for valid group and severity vals */
+	switch (expinfo->group) {
+		case PI_CHECKSUM:
+		case PI_SEQUENCE:
+		case PI_RESPONSE_CODE:
+		case PI_REQUEST_CODE:
+		case PI_UNDECODED:
+		case PI_REASSEMBLE:
+		case PI_MALFORMED:
+		case PI_DEBUG:
+		case PI_PROTOCOL:
+		case PI_SECURITY:
+		case PI_COMMENTS_GROUP:
+		case PI_DECRYPTION:
+		case PI_ASSUMPTION:
+		case PI_DEPRECATED:
+			break;
+		default:
+			REPORT_DISSECTOR_BUG("Expert info for %s has invalid group=0x%08x\n", expinfo->name, expinfo->group);
+	}
+	switch (expinfo->severity) {
+		case PI_COMMENT:
+		case PI_CHAT:
+		case PI_NOTE:
+		case PI_WARN:
+		case PI_ERROR:
+			break;
+		default:
+			REPORT_DISSECTOR_BUG("Expert info for %s has invalid severity=0x%08x\n", expinfo->name, expinfo->severity);
+	}
+
+	expinfo->protocol      = module->proto_name;
+
+	/* if we always add and never delete, then id == len - 1 is correct */
+	if (gpa_expertinfo.len >= gpa_expertinfo.allocated_len) {
+		if (!gpa_expertinfo.ei) {
+			gpa_expertinfo.allocated_len = PRE_ALLOC_EXPERT_FIELDS_MEM;
+			gpa_expertinfo.ei = (expert_field_info **)g_malloc(sizeof(expert_field_info *)*PRE_ALLOC_EXPERT_FIELDS_MEM);
+		} else {
+			gpa_expertinfo.allocated_len += 1000;
+			gpa_expertinfo.ei = (expert_field_info **)g_realloc(gpa_expertinfo.ei,
+						   sizeof(expert_field_info *)*gpa_expertinfo.allocated_len);
+		}
+	}
+	gpa_expertinfo.ei[gpa_expertinfo.len] = expinfo;
+	gpa_expertinfo.len++;
+	expinfo->id = gpa_expertinfo.len - 1;
+	/* Save the original severity so it can be restored by the UAT */
+	expinfo->orig_severity = expinfo->severity;
+
+	/* save field name for lookup */
+	g_hash_table_insert(gpa_name_map, (gpointer) (expinfo->name), expinfo);
+
+	return expinfo->id;
+}
+
+
+/* for use with static arrays only, since we don't allocate our own copies
+of the expert_field_info struct contained within the exp_register_info struct */
+void
+expert_register_field_array(expert_module_t *module, ei_register_info *exp, const int num_records)
+{
+	int		  i;
+	ei_register_info *ptr = exp;
+
+	for (i = 0; i < num_records; i++, ptr++) {
+		/*
+		 * Make sure we haven't registered this yet.
+		 * Most fields have variables associated with them
+		 * that are initialized to -1; some have array elements,
+		 * or possibly uninitialized variables, so we also allow
+		 * 0 (which is unlikely to be the field ID we get back
+		 * from "expert_register_field_init()").
+		 */
+		if (ptr->ids->ei != -1 && ptr->ids->ei != 0) {
+			fprintf(stderr,
+				"Duplicate field detected in call to expert_register_field_array: '%s' is already registered, name=%s\n",
+				ptr->eiinfo.summary, ptr->eiinfo.name);
+			return;
+		}
+
+		/* Register the field with the experts */
+		ptr->ids->ei = expert_register_field_init(&ptr->eiinfo, module);
+
+		/* Register with the header field info, so it's display filterable */
+		ptr->eiinfo.hf_info.p_id = &ptr->ids->hf;
+		ptr->eiinfo.hf_info.hfinfo.name = ptr->eiinfo.summary;
+		ptr->eiinfo.hf_info.hfinfo.abbrev = ptr->eiinfo.name;
+
+		proto_register_field_array(module->proto_id, &ptr->eiinfo.hf_info, 1);
+	}
+}
+
+/* Finds a record in the expert array by name.
+ * For the moment, this function is only used "internally"
+ * but may find a reason to be exported
+ */
+static expert_field_info *
+expert_registrar_get_byname(const char *field_name)
+{
+	expert_field_info *hfinfo;
+
+	if (!field_name)
+		return NULL;
+
+	hfinfo = (expert_field_info*)g_hash_table_lookup(gpa_name_map, field_name);
+
+	return hfinfo;
+}
+
+/**
+ * Get summary text of an expert_info field.
+ * This is intended for use in expert_add_info_format or proto_tree_add_expert_format
+ * to get the "base" string to then append additional information
+ */
+const gchar* expert_get_summary(expert_field *eiindex)
+{
+	expert_field_info *eiinfo;
+
+	/* Look up the item */
+	EXPERT_REGISTRAR_GET_NTH(eiindex->ei, eiinfo);
+
+	return eiinfo->summary;
+}
+
+/** clear flags according to the mask and set new flag values */
+#define FI_REPLACE_FLAGS(fi, mask, flags_in) { \
+	(fi->flags = (fi)->flags & ~(mask)); \
+	(fi->flags = (fi)->flags | (flags_in)); \
+}
+
+/* set's the PI_ flags to a protocol item
+ * (and its parent items till the toplevel) */
+static void
+expert_set_item_flags(proto_item *pi, const int group, const guint severity)
+{
+	if (pi != NULL && PITEM_FINFO(pi) != NULL && (severity >= FI_GET_FLAG(PITEM_FINFO(pi), PI_SEVERITY_MASK))) {
+		FI_REPLACE_FLAGS(PITEM_FINFO(pi), PI_GROUP_MASK, group);
+		FI_REPLACE_FLAGS(PITEM_FINFO(pi), PI_SEVERITY_MASK, severity);
+
+		/* propagate till toplevel item */
+		pi = proto_item_get_parent(pi);
+		expert_set_item_flags(pi, group, severity);
+	}
+}
+
+static proto_tree*
+expert_create_tree(proto_item *pi, int group, int severity, const char *msg)
+{
+	proto_tree *tree;
+	proto_item *ti;
+
+	tree = proto_item_add_subtree(pi, ett_expert);
+	ti = proto_tree_add_protocol_format(tree, proto_expert, NULL, 0, 0, "Expert Info (%s/%s): %s",
+					    val_to_str(severity, expert_severity_vals, "Unknown (%u)"),
+					    val_to_str(group, expert_group_vals, "Unknown (%u)"),
+					    msg);
+	proto_item_set_generated(ti);
+
+	if (group == PI_MALFORMED) {
+		/* Add hidden malformed protocol filter */
+		proto_item *malformed_ti = proto_tree_add_item(tree, proto_malformed, NULL, 0, 0, ENC_NA);
+		proto_item_set_hidden(malformed_ti);
+	}
+
+	return proto_item_add_subtree(ti, ett_subexpert);
+}
+
+static proto_tree*
+expert_set_info_vformat(packet_info *pinfo, proto_item *pi, int group, int severity, int hf_index, gboolean use_vaformat,
+			const char *format, va_list ap)
+{
+	char           formatted[ITEM_LABEL_LENGTH];
+	int            pos;
+	int            tap;
+	expert_info_t *ei;
+	proto_tree    *tree;
+	proto_item    *ti;
+
+	if (pinfo == NULL && pi && pi->tree_data) {
+		pinfo = PTREE_DATA(pi)->pinfo;
+	}
+
+	/* if this packet isn't loaded because of a read filter, don't output anything */
+	if (pinfo == NULL || pinfo->num == 0) {
+		return NULL;
+	}
+
+	if (severity > highest_severity) {
+		highest_severity = severity;
+	}
+
+	/* XXX: can we get rid of these checks and make them programming errors instead now? */
+	if (pi != NULL && PITEM_FINFO(pi) != NULL) {
+		expert_set_item_flags(pi, group, severity);
+	}
+
+	if ((pi == NULL) || (PITEM_FINFO(pi) == NULL) ||
+		((guint)severity >= FI_GET_FLAG(PITEM_FINFO(pi), PI_SEVERITY_MASK))) {
+		col_add_str(pinfo->cinfo, COL_EXPERT, val_to_str(severity, expert_severity_vals, "Unknown (%u)"));
+	}
+
+	if (use_vaformat) {
+		pos = vsnprintf(formatted, ITEM_LABEL_LENGTH, format, ap);
+	} else {
+		pos = (int)g_strlcpy(formatted, format, ITEM_LABEL_LENGTH);
+	}
+
+	/* Both vsnprintf and g_strlcpy return the number of bytes attempted
+         * to write.
+         */
+        if (pos >= ITEM_LABEL_LENGTH) {
+		/* Truncation occured. It might have split a UTF-8 character. */
+		ws_utf8_truncate(formatted, ITEM_LABEL_LENGTH - 1);
+	}
+
+	tree = expert_create_tree(pi, group, severity, formatted);
+
+	if (hf_index == -1) {
+		/* If no filterable expert info, just add the message */
+		ti = proto_tree_add_string(tree, hf_expert_msg, NULL, 0, 0, formatted);
+		proto_item_set_generated(ti);
+	} else {
+		/* If filterable expert info, hide the "generic" form of the message,
+		   and generate the formatted filterable expert info */
+		ti = proto_tree_add_none_format(tree, hf_index, NULL, 0, 0, "%s", formatted);
+		proto_item_set_generated(ti);
+		ti = proto_tree_add_string(tree, hf_expert_msg, NULL, 0, 0, formatted);
+		proto_item_set_hidden(ti);
+	}
+
+	ti = proto_tree_add_uint_format_value(tree, hf_expert_severity, NULL, 0, 0, severity,
+					      "%s", val_to_str_const(severity, expert_severity_vals, "Unknown"));
+	proto_item_set_generated(ti);
+	ti = proto_tree_add_uint_format_value(tree, hf_expert_group, NULL, 0, 0, group,
+					      "%s", val_to_str_const(group, expert_group_vals, "Unknown"));
+	proto_item_set_generated(ti);
+
+	tap = have_tap_listener(expert_tap);
+
+	if (!tap)
+		return tree;
+
+	ei = wmem_new(pinfo->pool, expert_info_t);
+
+	ei->packet_num  = pinfo->num;
+	ei->group       = group;
+	ei->severity    = severity;
+	ei->hf_index    = hf_index;
+	ei->protocol    = pinfo->current_proto;
+	ei->summary     = wmem_strdup(pinfo->pool, formatted);
+
+	/* if we have a proto_item (not a faked item), set expert attributes to it */
+	if (pi != NULL && PITEM_FINFO(pi) != NULL) {
+		ei->pitem = pi;
+	}
+	/* XXX: remove this because we don't have an internal-only function now? */
+	else {
+		ei->pitem = NULL;
+	}
+
+	tap_queue_packet(expert_tap, pinfo, ei);
+	return tree;
+}
+
+/* Helper function for expert_add_info() to work around compiler's special needs on ARM */
+static inline proto_tree*
+expert_add_info_internal(packet_info *pinfo, proto_item *pi, expert_field *expindex, ...)
+{
+	/* the va_list is ignored */
+	va_list            unused;
+	expert_field_info *eiinfo;
+	proto_tree        *tree;
+
+	/* Look up the item */
+	EXPERT_REGISTRAR_GET_NTH(expindex->ei, eiinfo);
+
+	va_start(unused, expindex);
+	tree = expert_set_info_vformat(pinfo, pi, eiinfo->group, eiinfo->severity, *eiinfo->hf_info.p_id, FALSE, eiinfo->summary, unused);
+	va_end(unused);
+	return tree;
+}
+
+proto_item *
+expert_add_info(packet_info *pinfo, proto_item *pi, expert_field *expindex)
+{
+	proto_tree        *tree;
+	tree = expert_add_info_internal(pinfo, pi, expindex);
+	return (proto_item *)tree;
+}
+
+proto_item *
+expert_add_info_format(packet_info *pinfo, proto_item *pi, expert_field *expindex, const char *format, ...)
+{
+	va_list            ap;
+	expert_field_info *eiinfo;
+	proto_tree        *tree;
+
+	/* Look up the item */
+	EXPERT_REGISTRAR_GET_NTH(expindex->ei, eiinfo);
+
+	va_start(ap, format);
+	tree = expert_set_info_vformat(pinfo, pi, eiinfo->group, eiinfo->severity, *eiinfo->hf_info.p_id, TRUE, format, ap);
+	va_end(ap);
+	return (proto_item *)tree;
+}
+
+/* Helper function for expert_add_expert() to work around compiler's special needs on ARM */
+static inline proto_item *
+proto_tree_add_expert_internal(proto_tree *tree, packet_info *pinfo, expert_field *expindex,
+		tvbuff_t *tvb, gint start, gint length, ...)
+{
+	expert_field_info *eiinfo;
+	proto_item        *ti;
+	gint               item_length, captured_length;
+	va_list            unused;
+
+	/* Look up the item */
+	EXPERT_REGISTRAR_GET_NTH(expindex->ei, eiinfo);
+
+	/* Make sure this doesn't throw an exception when adding the item */
+	item_length = length;
+	captured_length = tvb_captured_length_remaining(tvb, start);
+	if (captured_length < 0)
+		item_length = 0;
+	else if (captured_length < item_length)
+		item_length = captured_length;
+	ti = proto_tree_add_text_internal(tree, tvb, start, item_length, "%s", eiinfo->summary);
+	va_start(unused, length);
+	expert_set_info_vformat(pinfo, ti, eiinfo->group, eiinfo->severity, *eiinfo->hf_info.p_id, FALSE, eiinfo->summary, unused);
+	va_end(unused);
+
+	/* But make sure it throws an exception *after* adding the item */
+	if (length != -1) {
+		tvb_ensure_bytes_exist(tvb, start, length);
+	}
+	return ti;
+}
+
+proto_item *
+proto_tree_add_expert(proto_tree *tree, packet_info *pinfo, expert_field *expindex,
+		tvbuff_t *tvb, gint start, gint length)
+{
+	return proto_tree_add_expert_internal(tree, pinfo, expindex, tvb, start, length);
+}
+
+proto_item *
+proto_tree_add_expert_format(proto_tree *tree, packet_info *pinfo, expert_field *expindex,
+		tvbuff_t *tvb, gint start, gint length, const char *format, ...)
+{
+	va_list            ap;
+	expert_field_info *eiinfo;
+	gint               item_length, captured_length;
+	proto_item        *ti;
+
+	/* Look up the item */
+	EXPERT_REGISTRAR_GET_NTH(expindex->ei, eiinfo);
+
+	/* Make sure this doesn't throw an exception when adding the item */
+	item_length = length;
+	captured_length = tvb_captured_length_remaining(tvb, start);
+	if (captured_length < 0)
+		item_length = 0;
+	else if (captured_length < item_length)
+		item_length = captured_length;
+	va_start(ap, format);
+	ti = proto_tree_add_text_valist_internal(tree, tvb, start, item_length, format, ap);
+	va_end(ap);
+
+	va_start(ap, format);
+	expert_set_info_vformat(pinfo, ti, eiinfo->group, eiinfo->severity, *eiinfo->hf_info.p_id, TRUE, format, ap);
+	va_end(ap);
+
+	/* But make sure it throws an exception *after* adding the item */
+	if (length != -1) {
+		tvb_ensure_bytes_exist(tvb, start, length);
+	}
+	return ti;
+}
+
+/*
+ * 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:
+ */