/* packet-opsi.c
 * Routines for OPSI protocol dissection
 * Copyright 2004, Laurent Rabret (France Telecom R&D) <laurent.rabret@i.hate.spams.org>
 *
 * 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"

#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>

#include "packet-tcp.h"

void proto_register_opsi(void);
void proto_reg_handoff_opsi(void);

static dissector_handle_t opsi_handle;

/* TCP destination port dedicated to the OPSI protocol */
#define TCP_PORT_OPSI		4002 /* Not IANA registered */

/* Information position in OPSI header */
#define MAJOR_VERSION_OFFSET	0
#define MINOR_VERSION_OFFSET	1
#define CODE_OFFSET		2
#define HOOK_ID_OFFSET		3
#define PACKET_LENGTH_OFFSET	4
#define SESSION_OFFSET		6

#define HEADER_LENGTH		8


/* Valid OPSI code values */
#define DISCOVER_REQUEST	1
#define DISCOVER_RESPONSE	2
#define SERVICE_REQUEST 	3
#define SERVICE_ACCEPT		4
#define SERVICE_REJECT		5
#define	TERMINATE_REQUEST	6

/* Internal structure to dissect attributes */
typedef struct {
	uint16_t		 attribute_type;	/* attribute code */
	const char	*tree_text;             /* text for fold out */
	int		*tree_id;               /* id for add_item */
	int             *hf_type_attribute;	/* id for search option */
	void		(*dissect)(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item,
				   int* hfValue, int offset, int length);
} opsi_attribute_handle_t;


/* Attributes codes */
#define USER_NAME_ATTRIBUTE		 1
#define USER_PASSWD_ATTRIBUTE		 2
#define CHAP_PASSWD_ATTRIBUTE		 3
#define NAS_IP_ADDRESS_ATTRIBUTE	 4
#define NAS_PORT_ATTRIBUTE		 5
#define SERVICE_TYPE_ATTRIBUTE		 6
#define FRAMED_PROTOCOL_ATTRIBUTE	 7
#define FRAMED_ADDRESS_ATTRIBUTE	 8
#define FRAMED_NETMASK_ATTRIBUTE	 9
#define FRAMED_ROUTING_ATTRIBUTE	10
#define FRAMED_FILTER_ATTRIBUTE		11
#define FRAMED_MTU_ATTRIBUTE		12
#define FRAMED_COMPRESSION_ATTRIBUTE	13
#define CALLED_STATION_ID_ATTRIBUTE	30
#define CALLING_STATION_ID_ATTRIBUTE	31
#define NAS_IDENTIFIER			32
#define ACCOUNTING_40_ATTRIBUTE		40
#define ACCOUNTING_41_ATTRIBUTE		41
#define ACCOUNTING_42_ATTRIBUTE		42
#define ACCOUNTING_43_ATTRIBUTE		43
#define ACCOUNTING_SESSION_ID_ATTRIBUTE	44
#define ACCOUNTING_45_ATTRIBUTE		45
#define ACCOUNTING_46_ATTRIBUTE		46
#define ACCOUNTING_47_ATTRIBUTE		47
#define ACCOUNTING_48_ATTRIBUTE		48
#define ACCOUNTING_49_ATTRIBUTE		49
#define ACCOUNTING_50_ATTRIBUTE		50
#define ACCOUNTING_51_ATTRIBUTE		51
#define ACCOUNTING_52_ATTRIBUTE		52
#define ACCOUNTING_53_ATTRIBUTE		53
#define ACCOUNTING_54_ATTRIBUTE		54
#define ACCOUNTING_55_ATTRIBUTE		55
#define ACCOUNTING_56_ATTRIBUTE		56
#define ACCOUNTING_57_ATTRIBUTE		57
#define ACCOUNTING_58_ATTRIBUTE		58
#define ACCOUNTING_59_ATTRIBUTE		59
#define CHAP_CHALLENGE_ATTRIBUTE	60
#define NAS_PORT_TYPE_ATTRIBUTE		61
#define DESIGNATION_NUMBER_ATTRIBUTE	77
#define NAS_PORT_ID_ATTRIBUTE		87

#define SMC_AAAID_ATTRIBUTE		651
#define SMC_VPNID_ATTRIBUTE		652
#define SMC_VPNNAME_ATTRIBUTE		653
#define SMC_RANID_ATTRIBUTE		654
#define SMC_RANIP_ATTRIBUTE		655
#define SMC_RANNAME_ATTRIBUTE		656
#define SMC_POPID_ATTRIBUTE		657
#define SMC_POPNAME_ATTRIBUTE		658
#define SMC_SMCID_ATTRIBUTE		659
#define SMC_RECEIVE_TIME_ATTRIBUTE	660
#define SMC_STAT_TIME_ATTRIBUTE		661

#define OPSI_FLAGS_ATTRIBUTE		674
#define OPSI_APPLICATION_NAME_ATTRIBUTE	675

/*
 * Published API functions.  NOTE, "local" API functions
 * only valid from the packet-opsi file.
 */
static void decode_string_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length);
static void decode_ipv4_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length);
static void decode_longint_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length);
static void decode_value_string_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length);
static void decode_time_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length);
/******* *******/

/* Initialize the protocol and registered fields */
static int proto_opsi;
static int hf_opsi_major_version;
static int hf_opsi_minor_version;
static int hf_opsi_opcode;
static int hf_opsi_hook_id;
static int hf_opsi_length;
static int hf_opsi_session_id;
static int hf_user_name_att;
static int hf_password_att;
static int hf_chap_password_att;
static int hf_nas_ip_add_att;
static int hf_nas_port_att;
static int hf_service_type_att;
static int hf_framed_protocol_att;
static int hf_framed_address_att;
static int hf_framed_netmask_att;
static int hf_framed_routing_att;
static int hf_framed_filter_att;
static int hf_framed_mtu_att;
static int hf_framed_compression_att;
static int hf_called_station_att;
static int hf_calling_station_att;
static int hf_nas_identifier_att;
static int hf_accounting_att;
static int hf_acct_session_id_att;
static int hf_chap_challenge_att;
static int hf_nas_port_type_att;
static int hf_designation_num_att;
static int hf_nas_port_id_att;
static int hf_smc_aaa_id_att;
static int hf_smc_vpn_id_att;
static int hf_smc_vpn_name_att;
static int hf_smc_ran_id_att;
static int hf_smc_ran_ip_att;
static int hf_smc_ran_name_att;
static int hf_smc_pop_id_att;
static int hf_smc_pop_name_att;
static int hf_smc_id_att;
static int hf_smc_receive_time_att;
static int hf_smc_stat_time_att;
static int hf_opsi_flags_att;
static int hf_opsi_application_name_att;
static int hf_opsi_attribute_length;

/* Initialize the subtree pointers */
static int ett_opsi;
static int ett_opsi_user_name;
static int ett_opsi_user_password;
static int ett_opsi_chap_password;
static int ett_opsi_nas_ip_address;
static int ett_opsi_nas_port;
static int ett_opsi_service_type;
static int ett_opsi_framed_protocol;
static int ett_opsi_framed_address;
static int ett_opsi_framed_netmask;
static int ett_opsi_framed_routing;
static int ett_opsi_framed_filter;
static int ett_opsi_framed_mtu;
static int ett_opsi_framed_compression;
static int ett_opsi_called_station_id;
static int ett_opsi_calling_station_id;
static int ett_opsi_nas_identifier;
static int ett_opsi_accounting;
static int ett_opsi_acct_session_id;
static int ett_opsi_chap_challenge;
static int ett_opsi_nas_port_type;
static int ett_opsi_designation_number;
static int ett_opsi_nas_port_id;
static int ett_opsi_smc_aaa_id;
static int ett_opsi_smc_vpn_id;
static int ett_opsi_smc_vpn_name;
static int ett_opsi_smc_ran_id;
static int ett_opsi_smc_ran_ip;
static int ett_opsi_smc_ran_name;
static int ett_opsi_smc_pop_id;
static int ett_opsi_smc_pop_name;
static int ett_opsi_smc_id;
static int ett_opsi_smc_receive_time;
static int ett_opsi_smc_stat_time;
static int ett_opsi_flags;
static int ett_opsi_application_name;

static expert_field ei_opsi_unknown_attribute;
static expert_field ei_opsi_short_attribute;
static expert_field ei_opsi_short_frame;

/* Code mapping */
static const value_string opsi_opcode[] = {
	{ DISCOVER_REQUEST,  "Discover Request" },
	{ DISCOVER_RESPONSE, "Discover Response" },
	{ SERVICE_REQUEST,   "Service Request" },
	{ SERVICE_ACCEPT,    "Service Accept" },
	{ SERVICE_REJECT,    "Service Reject" },
	{ TERMINATE_REQUEST, "Terminate Request" },
	{ 0, NULL }
};

static const value_string opsi_service_type_code[] = {
	{ 1, "Login" },
	{ 2, "Framed" },
	{ 3, "Callback Login" },
	{ 4, "Callback Framed" },
	{ 5, "Outbound" },
	{ 6, "Administrative" },
	{ 7, "NAS Prompt" },
	{ 8, "Authenticate Only" },
	{ 9, "Callback NAS Prompt" },
	{ 0, NULL }
};

static const value_string opsi_framed_protocol_code[] = {
	{   1, "PPP" },
	{   2, "SLIP" },
	{   3, "AppleTalk Remote Access Protocol (ARAP)" },
	{   4, "Gandalf proprietary SingleLink/MultiLink protocol" },
	{   5, "Xylogics proprietary IPX/SLIP" },
	{ 255, "Ascend ARA" },
	{ 256, "MPP" },
	{ 257, "EURAW" },
	{ 258, "EUUI" },
	{ 259, "X25" },
	{ 260, "COMB" },
	{ 261, "FR" },
	{ 262, "MP" },
	{ 263, "FR-CIR"},
	{ 0, NULL }
};

static const value_string opsi_framed_routing_code[] = {
	{ 0, "None" },
	{ 1, "Broadcast" },
	{ 2, "Listen" },
	{ 3, "Broadcast-Listen" },
	{ 4, "Broadcast V2" },
	{ 5, "Listen V2" },
	{ 6, "Broadcast-Listen V2" },
	{ 0, NULL },
};

static const value_string opsi_framed_compression_code[] = {
	{ 0, "None" },
	{ 1, "Van Jacobsen TCP/IP" },
	{ 2, "IPX header compression" },
	{ 0, NULL }
};

static const value_string opsi_nas_port_type_code[] = {
	{   0, "Async" },
	{   1, "Sync" },
	{   2, "ISDN Sync" },
	{   3, "ISDN Async V.120" },
	{   4, "ISDN Async V.110" },
	{   5, "Virtual" },
	{   6, "PIAFS" },
	{   7, "HDLC Clear Channel" },
	{   8, "X.25" },
	{   9, "X.75" },
	{  10, "G.3 Fax" },
	{  11, "SDSL - Symmetric DSL" },
	{  12, "ADSL-CAP - Asymmetric DSL, Carrierless Amplitude Phase Modulation" },
	{  13, "ADSL-DMT - Asymmetric DSL, Discrete Multi-Tone" },
	{  14, "IDSL - ISDN Digital Subscriber Line" },
	{  15, "Ethernet" },
	{  16, "xDSL - Digital Subscriber Line of unknown type" },
	{  17, "Cable" },
	{  18, "Wireless - Other" },
	{  19, "Wireless - IEEE 802.11" },
	{ 201, "Voice over IP" },
	{ 0, NULL }
};


/* Structure used to decode OPSI frame attributes	*/
/* CAUTION : it is compulsory to sort this array	*/
/* (first argument of the opsi_attribute_handle_t)	*/
/* in ascending order 					*/
/*							*/
static const opsi_attribute_handle_t opsi_attributes[] = {
	{ USER_NAME_ATTRIBUTE,		  /* 1 */
	"User name attribute",		   &ett_opsi_user_name, &hf_user_name_att, decode_string_attribute },
	{ USER_PASSWD_ATTRIBUTE,	  /* 2 */
	"User password attribute" ,	   &ett_opsi_user_password, &hf_password_att, decode_string_attribute },
	{ CHAP_PASSWD_ATTRIBUTE,	  /* 3 */
	"CHAP password attribute",	   &ett_opsi_chap_password, &hf_chap_password_att, decode_string_attribute },
	{ NAS_IP_ADDRESS_ATTRIBUTE,	  /* 4 */
	"NAS IP address attribute",	   &ett_opsi_nas_ip_address, &hf_nas_ip_add_att, decode_ipv4_attribute },
	{NAS_PORT_ATTRIBUTE,		  /* 5 */
	"NAS port attribute",		   &ett_opsi_nas_port, &hf_nas_port_att, decode_longint_attribute },
	{SERVICE_TYPE_ATTRIBUTE,	  /* 6 */
	"Service type attribute",	   &ett_opsi_service_type, &hf_service_type_att, decode_value_string_attribute },
	{FRAMED_PROTOCOL_ATTRIBUTE,	  /* 7 */
	"Framed protocol attribute",	   &ett_opsi_framed_protocol, &hf_framed_protocol_att, decode_value_string_attribute },
	{FRAMED_ADDRESS_ATTRIBUTE,	  /* 8 */
	"Framed address attribute",	   &ett_opsi_framed_address, &hf_framed_address_att, decode_ipv4_attribute },
	{FRAMED_NETMASK_ATTRIBUTE,	  /* 9 */
	"Framed netmask attribute",	   &ett_opsi_framed_netmask, &hf_framed_netmask_att, decode_ipv4_attribute },
	{FRAMED_ROUTING_ATTRIBUTE,	  /* 10 */
	"Framed routing attribute",	   &ett_opsi_framed_routing, &hf_framed_routing_att, decode_value_string_attribute },
	{FRAMED_FILTER_ATTRIBUTE,	  /* 11 */
	"Framed filter attribute",	   &ett_opsi_framed_filter, &hf_framed_filter_att, decode_string_attribute },
	{FRAMED_MTU_ATTRIBUTE,		  /* 12 */
	"Framed MTU attribute",		   &ett_opsi_framed_mtu, &hf_framed_mtu_att, decode_longint_attribute },
	{FRAMED_COMPRESSION_ATTRIBUTE,	  /* 13 */
	"Framed compression attribute",	   &ett_opsi_framed_compression, &hf_framed_compression_att, decode_value_string_attribute },
	{CALLED_STATION_ID_ATTRIBUTE,	  /* 30 */
	"Called station ID attribute",	   &ett_opsi_called_station_id, &hf_called_station_att, decode_string_attribute },
	{CALLING_STATION_ID_ATTRIBUTE,	  /* 31 */
	"Calling station ID attribute",	   &ett_opsi_calling_station_id, &hf_calling_station_att, decode_string_attribute },
	{NAS_IDENTIFIER,		  /* 32 */
	"NAS Identifier attribute",	   &ett_opsi_nas_identifier, &hf_nas_identifier_att, decode_string_attribute },
	{ACCOUNTING_40_ATTRIBUTE,	  /* 40 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_41_ATTRIBUTE,	  /* 41 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_42_ATTRIBUTE,	  /* 42 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_43_ATTRIBUTE,	  /* 43 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_SESSION_ID_ATTRIBUTE, /* 44 */
	"Accounting session ID attribute", &ett_opsi_acct_session_id, &hf_acct_session_id_att, decode_string_attribute },
	{ACCOUNTING_45_ATTRIBUTE,	  /* 45 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_46_ATTRIBUTE,	  /* 46 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_47_ATTRIBUTE,	  /* 47 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_48_ATTRIBUTE,	  /* 48 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_49_ATTRIBUTE,	  /* 49 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_50_ATTRIBUTE,	  /* 50 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_51_ATTRIBUTE,	  /* 51 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_52_ATTRIBUTE,	  /* 52 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_53_ATTRIBUTE,	  /* 53 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_54_ATTRIBUTE,	  /* 54 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_55_ATTRIBUTE,	  /* 55 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_56_ATTRIBUTE,	  /* 56 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_57_ATTRIBUTE,	  /* 57 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_58_ATTRIBUTE,	  /* 58 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{ACCOUNTING_59_ATTRIBUTE,	  /* 59 */
	"Accounting attribute",		   &ett_opsi_accounting, &hf_accounting_att, decode_string_attribute },
	{CHAP_CHALLENGE_ATTRIBUTE,	  /* 60 */
	"CHAP challenge",		   &ett_opsi_chap_challenge, &hf_chap_challenge_att, decode_string_attribute },
	{NAS_PORT_TYPE_ATTRIBUTE,	  /* 61 */
	"NAS port type attribute",	   &ett_opsi_nas_port_type, &hf_nas_port_type_att, decode_value_string_attribute },
	{DESIGNATION_NUMBER_ATTRIBUTE,	  /* 77 */
	"Designation number attribute",	   &ett_opsi_designation_number, &hf_designation_num_att, decode_string_attribute },
	{NAS_PORT_ID_ATTRIBUTE,		  /* 87 */
	"NAS port ID attribute",	   &ett_opsi_nas_port_id, &hf_nas_port_id_att, decode_string_attribute },
	{SMC_AAAID_ATTRIBUTE,		  /* 651 */
	"SMC AAA ID attribute",		   &ett_opsi_smc_aaa_id, &hf_smc_aaa_id_att, decode_longint_attribute },
	{SMC_VPNID_ATTRIBUTE,		  /* 652 */
	"SMC VPN ID attribute",		   &ett_opsi_smc_vpn_id, &hf_smc_vpn_id_att, decode_longint_attribute },
	{SMC_VPNNAME_ATTRIBUTE,		  /* 653 */
	"SMC VPN name attribute",	   &ett_opsi_smc_vpn_name, &hf_smc_vpn_name_att, decode_string_attribute },
	{SMC_RANID_ATTRIBUTE,		  /* 654 */
	"SMC RAN ID attribute",		   &ett_opsi_smc_ran_id, &hf_smc_ran_id_att, decode_longint_attribute },
	{SMC_RANIP_ATTRIBUTE,		  /* 655 */
	"SMC RAN IP attribute",		   &ett_opsi_smc_ran_ip, &hf_smc_ran_ip_att, decode_ipv4_attribute },
	{SMC_RANNAME_ATTRIBUTE,		  /* 656 */
	"SMC RAN name attribute",	   &ett_opsi_smc_ran_name, &hf_smc_ran_name_att, decode_string_attribute },
	{SMC_POPID_ATTRIBUTE,		  /* 657 */
	"SMC POP ID attribute",		   &ett_opsi_smc_pop_id, &hf_smc_pop_id_att, decode_longint_attribute },
	{SMC_POPNAME_ATTRIBUTE,		  /* 658 */
	"SMC POP name attribute",	   &ett_opsi_smc_pop_name, &hf_smc_pop_name_att, decode_string_attribute },
	{SMC_SMCID_ATTRIBUTE,		  /* 659 */
	"SMC ID attribute",		   &ett_opsi_smc_id, &hf_smc_id_att, decode_longint_attribute },
	{SMC_RECEIVE_TIME_ATTRIBUTE,	  /* 660 */
	"SMC receive time attribute",	   &ett_opsi_smc_receive_time, &hf_smc_receive_time_att, decode_time_attribute },
	{SMC_STAT_TIME_ATTRIBUTE,	  /* 661 */
	"SMC stat time attribute",	   &ett_opsi_smc_stat_time, &hf_smc_stat_time_att, decode_longint_attribute },
	{OPSI_FLAGS_ATTRIBUTE,		  /* 674 */
	"OPSI flags attribute",		   &ett_opsi_flags, &hf_opsi_flags_att, decode_longint_attribute },
	{OPSI_APPLICATION_NAME_ATTRIBUTE, /* 675 */
	"OPSI application name attribute", &ett_opsi_application_name, &hf_opsi_application_name_att, decode_string_attribute },

};

/* Desegmentation of OPSI (over TCP) */
static bool opsi_desegment = true;

static void
decode_string_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length)
{
	if (length < 4) {
		expert_add_info(pinfo, item, &ei_opsi_short_attribute);
		return;
	}

	proto_tree_add_item(tree, *hfValue, tvb, offset+4, length-4, ENC_ASCII|ENC_NA);
}


static void
decode_ipv4_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length)
{
	if (length < 8) {
		expert_add_info(pinfo, item, &ei_opsi_short_attribute);
		return;
	}
	proto_tree_add_item(tree, *hfValue, tvb, offset+4, 4, ENC_BIG_ENDIAN);
}

static void
decode_longint_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length)
{
	if (length < 8) {
		expert_add_info(pinfo, item, &ei_opsi_short_attribute);
		return;
	}
	proto_tree_add_item(tree, *hfValue, tvb, offset+4, 4, ENC_BIG_ENDIAN);
}

static void
decode_value_string_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length)
{
	if (length < 8) {
		expert_add_info(pinfo, item, &ei_opsi_short_attribute);
		return;
	}
	proto_tree_add_item(tree, *hfValue, tvb, offset+4, 4, ENC_BIG_ENDIAN);
}

static void
decode_time_attribute(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_item *item, int* hfValue, int offset, int length)
{
	if (length < 8) {
		expert_add_info(pinfo, item, &ei_opsi_short_attribute);
		return;
	}
	proto_tree_add_item(tree, *hfValue, tvb, offset+4, 4, ENC_TIME_SECS|ENC_BIG_ENDIAN);
}

/****************************************************************************/
/********** End of attribute decoding ***************************************/
/****************************************************************************/

/* To find the correct size of the PDU. Needed by the desegmentation feature*/
static unsigned
get_opsi_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
{
	/*
	 * Get the length of the OPSI packet.
	 * We are guaranteed there're enough chars in tvb in order to
	 * extract the length value. No exception thrown !!
	 */
	return tvb_get_ntohs(tvb, offset + 4);
}

static int
opsi_attribute_compar(const void *key, const void *member)
{
	return *(const int *)key - ((const opsi_attribute_handle_t *)member)->attribute_type;
}

static void
dissect_attributes(tvbuff_t *tvb, packet_info *pinfo, proto_tree *opsi_tree, int offset, int length)
{
	int attribute_type;
	int attribute_length;
	proto_item *ti;
	proto_tree *ntree = NULL;

	while (length >= 4) {
		const opsi_attribute_handle_t *attr;
		attribute_type 		= tvb_get_ntohs(tvb, offset);
		attribute_length 	= tvb_get_ntohs(tvb, offset+2);
		if (attribute_length > length) break;
		/* We perform a standard log(n) lookup */

		attr = bsearch(&attribute_type, opsi_attributes, array_length(opsi_attributes), sizeof opsi_attributes[0], opsi_attribute_compar);
		if (attr == NULL) {
			proto_tree_add_expert_format(opsi_tree, pinfo, &ei_opsi_unknown_attribute, tvb, offset, attribute_length,
										"Unknown attribute (%d)", attribute_type);
		} else {
			ntree = proto_tree_add_subtree_format(opsi_tree, tvb, offset, attribute_length, *attr->tree_id, &ti,
								"%s (%d)", attr->tree_text, attribute_type);
			proto_tree_add_item(ntree, hf_opsi_attribute_length, tvb, offset+2, 2, ENC_BIG_ENDIAN);
			attr->dissect(tvb, pinfo, ntree, ti, attr->hf_type_attribute, offset, attribute_length);
		}
		if (attribute_length < 4) {
			/* Length must be at least 4, for the type and length. */
			break;
		}
		offset += attribute_length;
		length -= attribute_length;
	}
	if (length) {
		proto_tree_add_expert_remaining(opsi_tree, pinfo, &ei_opsi_short_frame, tvb, offset);
	}
}

static int
dissect_opsi_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
	proto_item *ti;
	proto_tree *opsi_tree;

	col_set_str(pinfo->cinfo, COL_PROTOCOL, "OPSI");
	col_clear(pinfo->cinfo, COL_INFO);

	col_append_sep_str(pinfo->cinfo, COL_INFO, ", ",
		val_to_str(pinfo->pool, tvb_get_uint8(tvb, CODE_OFFSET), opsi_opcode,
			"<Unknown opcode %d>"));
	col_set_fence(pinfo->cinfo, COL_INFO);

	ti = proto_tree_add_item(tree, proto_opsi, tvb, 0, -1, ENC_NA);
	opsi_tree = proto_item_add_subtree(ti, ett_opsi);

	if (opsi_tree) {
		proto_tree_add_item(opsi_tree, hf_opsi_major_version, tvb, MAJOR_VERSION_OFFSET, 1, ENC_BIG_ENDIAN);
		proto_tree_add_item(opsi_tree, hf_opsi_minor_version, tvb, MINOR_VERSION_OFFSET, 1, ENC_BIG_ENDIAN);
		proto_tree_add_item(opsi_tree, hf_opsi_opcode, tvb, CODE_OFFSET, 1, ENC_BIG_ENDIAN);
		proto_tree_add_item(opsi_tree, hf_opsi_hook_id, tvb, HOOK_ID_OFFSET, 1, ENC_BIG_ENDIAN);
		proto_tree_add_item(opsi_tree, hf_opsi_length, tvb, PACKET_LENGTH_OFFSET, 2, ENC_BIG_ENDIAN);
		proto_tree_add_item(opsi_tree, hf_opsi_session_id, tvb, SESSION_OFFSET, 2, ENC_BIG_ENDIAN);
	}

	dissect_attributes(tvb, pinfo, opsi_tree, HEADER_LENGTH, MIN(((int)tvb_reported_length(tvb)-HEADER_LENGTH), (tvb_get_ntohs(tvb, PACKET_LENGTH_OFFSET)-HEADER_LENGTH)));
	return tvb_reported_length(tvb);
}


static int
dissect_opsi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
	/* We should minimally grab the header */
	tcp_dissect_pdus(tvb, pinfo, tree, opsi_desegment, HEADER_LENGTH, get_opsi_pdu_len,
		dissect_opsi_pdu, data);
	return tvb_reported_length(tvb);
}


void
proto_register_opsi(void)
{

/* Setup list of header fields  See Section 1.6.1 for details*/
	static hf_register_info hf[] = {
		{ &hf_opsi_major_version,
			{ "Major version",           "opsi.major",
			FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }
		},
		{ &hf_opsi_minor_version,
			{ "Minor version",           "opsi.minor",
			FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }
		},
		{ &hf_opsi_opcode,
		        { "Operation code",		"opsi.opcode",
		        FT_UINT8, BASE_DEC, VALS(opsi_opcode), 0x0,
		        NULL, HFILL }
		},
		{ &hf_opsi_hook_id,
			{ "Hook ID",			"opsi.hook",
			FT_UINT8, BASE_DEC, NULL, 0x0,
			NULL, HFILL }
		},
		{ &hf_opsi_length,
			{ "Message length",		"opsi.length",
			FT_UINT16, BASE_DEC, NULL, 0x0,
			NULL, HFILL }
		},
		{ &hf_opsi_session_id,
			{ "Session ID",			"opsi.session_id",
			FT_UINT16, BASE_DEC, NULL, 0x0,
			NULL, HFILL }
		},
		{ &hf_user_name_att,
			{ "User name",			"opsi.attr.user_name",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_password_att,
			{ "User password",		"opsi.attr.password",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_chap_password_att,
			{ "CHAP password attribute",	"opsi.attr.chap_password",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_nas_ip_add_att,
			{ "NAS IP address",		"opsi.attr.nas_ip_addr",
			FT_IPv4, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_nas_port_att,
			{ "NAS port",			"opsi.attr.nas_port",
			FT_UINT32, BASE_HEX, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_service_type_att,
		        { "Service type",		"opsi.attr.service_type",
			FT_UINT32, BASE_DEC, VALS(opsi_service_type_code), 0x0,
			NULL, HFILL }
		},
		{ &hf_framed_protocol_att,
			{ "Framed protocol",		"opsi.attr.framed_protocol",
			FT_UINT32, BASE_DEC, VALS(opsi_framed_protocol_code), 0x0,
			NULL, HFILL }
		},
		{ &hf_framed_address_att,
			{ "Framed address",		"opsi.attr.framed_address",
			FT_IPv4, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_framed_netmask_att,
			{ "Framed netmask",		"opsi.attr.framed_netmask",
			FT_IPv4, BASE_NETMASK, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_framed_routing_att,
			{ "Framed routing",		"opsi.attr.framed_routing",
			FT_UINT32, BASE_DEC, VALS(opsi_framed_routing_code), 0x0,
			NULL, HFILL }
		},
		{ &hf_framed_filter_att,
			{ "Framed filter",		"opsi.attr.framed_filter",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_framed_mtu_att,
			{ "Framed MTU",		"opsi.attr.framed_mtu",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_framed_compression_att,
			{ "Framed compression",		"opsi.attr.framed_compression",
			FT_UINT32, BASE_DEC, VALS(opsi_framed_compression_code), 0x0,
			NULL, HFILL }
		},
		{ &hf_called_station_att,
			{ "Called station ID",		"opsi.attr.called_station_id",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_calling_station_att,
			{ "Calling station ID",		"opsi.attr.calling_station_id",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_nas_identifier_att,
			{ "NAS ID",			"opsi.attr.nas_id",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_accounting_att,
			{ "Accounting",			"opsi.attr.accounting",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_acct_session_id_att,
			{ "Accounting session ID",	"opsi.attr.acct.session_id",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_chap_challenge_att,
			{ "CHAP challenge",		"opsi.attr.chap_challenge",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_nas_port_type_att,
			{ "NAS port type",		"opsi.attr.nas_port_type",
			FT_UINT32, BASE_DEC, VALS(opsi_nas_port_type_code), 0x0,
			NULL, HFILL }
		},
		{ &hf_designation_num_att,
			{ "Designation number",		"opsi.attr.designation_number",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_nas_port_id_att,
			{ "NAS port ID", 		"opsi.attr.nas_port_id",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_aaa_id_att,
			{ "SMC AAA ID",			"opsi.attr.smc_aaa_id",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_vpn_id_att,
			{ "SMC VPN ID",			"opsi.attr.smc_vpn_id",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_vpn_name_att,
			{ "SMC VPN name",		"opsi.attr.smc_vpn_name",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_ran_id_att,
			{ "SMC RAN ID",			"opsi.attr.smc_ran_id",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_ran_ip_att,
			{ "SMC RAN IP address",		"opsi.attr.smc_ran_ip",
			FT_IPv4, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_ran_name_att,
			{ "SMC RAN name",		"opsi.attr.smc_ran_name",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_pop_id_att,
			{ "SMC POP id",			"opsi.attr.smc_pop_id",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_pop_name_att,
			{ "SMC POP name",		"opsi.attr.smc_pop_name",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_id_att,
			{ "SMC ID",			"opsi.attr.smc_id",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_receive_time_att,
			{ "SMC receive time",		"opsi.attr.smc_receive_time",
			FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_smc_stat_time_att,
			{ "SMC stat time",		"opsi.attr.smc_stat_time",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_opsi_flags_att,
			{ "OPSI flags",			"opsi.attr.flags",
			FT_UINT32, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_opsi_application_name_att,
			{ "OPSI application name",	"opsi.attr.application_name",
			FT_STRING, BASE_NONE, NULL, 0x00,
			NULL, HFILL }
		},
		{ &hf_opsi_attribute_length,
			{ "Length",	"opsi.attr_length",
			FT_UINT16, BASE_DEC, NULL, 0x00,
			NULL, HFILL }
		},
	};

/* Setup protocol subtree array */
	static int *ett[] = {
		&ett_opsi,
		&ett_opsi_user_name,
		&ett_opsi_user_password,
		&ett_opsi_chap_password,
		&ett_opsi_nas_ip_address,
		&ett_opsi_nas_port,
		&ett_opsi_service_type,
		&ett_opsi_framed_protocol,
		&ett_opsi_framed_address,
		&ett_opsi_framed_netmask,
		&ett_opsi_framed_routing,
		&ett_opsi_framed_filter,
		&ett_opsi_framed_mtu,
		&ett_opsi_framed_compression,
		&ett_opsi_called_station_id,
		&ett_opsi_calling_station_id,
		&ett_opsi_nas_identifier,
		&ett_opsi_accounting,
		&ett_opsi_acct_session_id,
		&ett_opsi_chap_challenge,
		&ett_opsi_nas_port_type,
		&ett_opsi_designation_number,
		&ett_opsi_nas_port_id,
		&ett_opsi_smc_aaa_id,
		&ett_opsi_smc_vpn_id,
		&ett_opsi_smc_vpn_name,
		&ett_opsi_smc_ran_id,
		&ett_opsi_smc_ran_ip,
		&ett_opsi_smc_ran_name,
		&ett_opsi_smc_pop_id,
		&ett_opsi_smc_pop_name,
		&ett_opsi_smc_id,
		&ett_opsi_smc_receive_time,
		&ett_opsi_smc_stat_time,
		&ett_opsi_flags,
		&ett_opsi_application_name,
	};

	static ei_register_info ei[] = {
		{ &ei_opsi_unknown_attribute, { "opsi.attr_unknown", PI_PROTOCOL, PI_WARN, "Unknown attribute", EXPFILL }},
		{ &ei_opsi_short_attribute, { "opsi.attr_too_short", PI_MALFORMED, PI_WARN, "Too short attribute!", EXPFILL }},
		{ &ei_opsi_short_frame, { "opsi.short_frame", PI_MALFORMED, PI_WARN, "Short frame", EXPFILL }},
	};

/* For desegmentation / reassembly */
	module_t *opsi_module;
	expert_module_t* expert_opsi;

/* Register the protocol name and description */
	proto_opsi = proto_register_protocol("Open Policy Service Interface", "OPSI", "opsi");

/* Required function calls to register the header fields and subtrees used */
	proto_register_field_array(proto_opsi, hf, array_length(hf));
	proto_register_subtree_array(ett, array_length(ett));
	expert_opsi = expert_register_protocol(proto_opsi);
	expert_register_field_array(expert_opsi, ei, array_length(ei));

/* We activate the desegmentation / reassembly feature */
	opsi_module = prefs_register_protocol(proto_opsi, NULL);
	prefs_register_bool_preference(opsi_module, "desegment_opsi_messages",
		"Reassemble OPSI messages spanning multiple TCP segments",
		"Whether the OPSI dissector should desegment all messages spanning multiple TCP segments",
		&opsi_desegment);

/* Register the dissector */
	opsi_handle = register_dissector("opsi", dissect_opsi, proto_opsi);
}


void
proto_reg_handoff_opsi(void)
{
	dissector_add_uint_with_preference("tcp.port", TCP_PORT_OPSI, opsi_handle);
}

/*
 * 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:
 */
