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packet-sna.c

/* packet-sna.c
 * Routines for SNA
 * Gilbert Ramirez <gram@alumni.rice.edu>
 * Jochen Friedrich <jochen@scram.de>
 *
 * $Id: packet-sna.c 13366 2005-02-09 23:38:00Z lroland $
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <glib.h>
#include <epan/packet.h>
#include "llcsaps.h"
#include "ppptypes.h"
#include <epan/sna-utils.h>
#include <epan/charsets.h>
#include <epan/prefs.h>
#include <epan/reassemble.h>

/*
 * http://www.wanresources.com/snacell.html
 * ftp://ftp.software.ibm.com/networking/pub/standards/aiw/formats/
 *
 */

static int proto_sna = -1;
static int proto_sna_xid = -1;
static int hf_sna_th = -1;
static int hf_sna_th_0 = -1;
static int hf_sna_th_fid = -1;
static int hf_sna_th_mpf = -1;
static int hf_sna_th_odai = -1;
static int hf_sna_th_efi = -1;
static int hf_sna_th_daf = -1;
static int hf_sna_th_oaf = -1;
static int hf_sna_th_snf = -1;
static int hf_sna_th_dcf = -1;
static int hf_sna_th_lsid = -1;
static int hf_sna_th_tg_sweep = -1;
static int hf_sna_th_er_vr_supp_ind = -1;
static int hf_sna_th_vr_pac_cnt_ind = -1;
static int hf_sna_th_ntwk_prty = -1;
static int hf_sna_th_tgsf = -1;
static int hf_sna_th_mft = -1;
static int hf_sna_th_piubf = -1;
static int hf_sna_th_iern = -1;
static int hf_sna_th_nlpoi = -1;
static int hf_sna_th_nlp_cp = -1;
static int hf_sna_th_ern = -1;
static int hf_sna_th_vrn = -1;
static int hf_sna_th_tpf = -1;
static int hf_sna_th_vr_cwi = -1;
static int hf_sna_th_tg_nonfifo_ind = -1;
static int hf_sna_th_vr_sqti = -1;
static int hf_sna_th_tg_snf = -1;
static int hf_sna_th_vrprq = -1;
static int hf_sna_th_vrprs = -1;
static int hf_sna_th_vr_cwri = -1;
static int hf_sna_th_vr_rwi = -1;
static int hf_sna_th_vr_snf_send = -1;
static int hf_sna_th_dsaf = -1;
static int hf_sna_th_osaf = -1;
static int hf_sna_th_snai = -1;
static int hf_sna_th_def = -1;
static int hf_sna_th_oef = -1;
static int hf_sna_th_sa = -1;
static int hf_sna_th_cmd_fmt = -1;
static int hf_sna_th_cmd_type = -1;
static int hf_sna_th_cmd_sn = -1;

static int hf_sna_nlp_nhdr = -1;
static int hf_sna_nlp_nhdr_0 = -1;
static int hf_sna_nlp_sm = -1;
static int hf_sna_nlp_tpf = -1;
static int hf_sna_nlp_nhdr_1 = -1;
static int hf_sna_nlp_ft = -1;
static int hf_sna_nlp_tspi = -1;
static int hf_sna_nlp_slowdn1 = -1;
static int hf_sna_nlp_slowdn2 = -1;
static int hf_sna_nlp_fra = -1;
static int hf_sna_nlp_anr = -1;
static int hf_sna_nlp_frh = -1;
static int hf_sna_nlp_thdr = -1;
static int hf_sna_nlp_tcid = -1;
static int hf_sna_nlp_thdr_8 = -1;
static int hf_sna_nlp_setupi = -1;
static int hf_sna_nlp_somi = -1;
static int hf_sna_nlp_eomi = -1;
static int hf_sna_nlp_sri = -1;
static int hf_sna_nlp_rasapi = -1;
static int hf_sna_nlp_retryi = -1;
static int hf_sna_nlp_thdr_9 = -1;
static int hf_sna_nlp_lmi = -1;
static int hf_sna_nlp_cqfi = -1;
static int hf_sna_nlp_osi = -1;
static int hf_sna_nlp_offset = -1;
static int hf_sna_nlp_dlf = -1;
static int hf_sna_nlp_bsn = -1;
static int hf_sna_nlp_opti_len = -1;
static int hf_sna_nlp_opti_type = -1;
static int hf_sna_nlp_opti_0d_version = -1;
static int hf_sna_nlp_opti_0d_4 = -1;
static int hf_sna_nlp_opti_0d_target = -1;
static int hf_sna_nlp_opti_0d_arb = -1;
static int hf_sna_nlp_opti_0d_reliable = -1;
static int hf_sna_nlp_opti_0d_dedicated = -1;
static int hf_sna_nlp_opti_0e_stat = -1;
static int hf_sna_nlp_opti_0e_gap = -1;
static int hf_sna_nlp_opti_0e_idle = -1;
static int hf_sna_nlp_opti_0e_nabsp = -1;
static int hf_sna_nlp_opti_0e_sync = -1;
static int hf_sna_nlp_opti_0e_echo = -1;
static int hf_sna_nlp_opti_0e_rseq = -1;
static int hf_sna_nlp_opti_0e_abspbeg = -1;
static int hf_sna_nlp_opti_0e_abspend = -1;
static int hf_sna_nlp_opti_0f_bits = -1;
static int hf_sna_nlp_opti_10_tcid = -1;
static int hf_sna_nlp_opti_12_sense = -1;
static int hf_sna_nlp_opti_14_si_len = -1;
static int hf_sna_nlp_opti_14_si_key = -1;
static int hf_sna_nlp_opti_14_si_2 = -1;
static int hf_sna_nlp_opti_14_si_refifo = -1;
static int hf_sna_nlp_opti_14_si_mobility = -1;
static int hf_sna_nlp_opti_14_si_dirsearch = -1;
static int hf_sna_nlp_opti_14_si_limitres = -1;
static int hf_sna_nlp_opti_14_si_ncescope = -1;
static int hf_sna_nlp_opti_14_si_mnpsrscv = -1;
static int hf_sna_nlp_opti_14_si_maxpsize = -1;
static int hf_sna_nlp_opti_14_si_switch = -1;
static int hf_sna_nlp_opti_14_si_alive = -1;
static int hf_sna_nlp_opti_14_rr_len = -1;
static int hf_sna_nlp_opti_14_rr_key = -1;
static int hf_sna_nlp_opti_14_rr_2 = -1;
static int hf_sna_nlp_opti_14_rr_bfe = -1;
static int hf_sna_nlp_opti_14_rr_num = -1;
static int hf_sna_nlp_opti_22_2 = -1;
static int hf_sna_nlp_opti_22_type = -1;
static int hf_sna_nlp_opti_22_raa = -1;
static int hf_sna_nlp_opti_22_parity = -1;
static int hf_sna_nlp_opti_22_arb = -1;
static int hf_sna_nlp_opti_22_3 = -1;
static int hf_sna_nlp_opti_22_ratereq = -1;
static int hf_sna_nlp_opti_22_raterep = -1;
static int hf_sna_nlp_opti_22_field1 = -1;
static int hf_sna_nlp_opti_22_field2 = -1;
static int hf_sna_nlp_opti_22_field3 = -1;
static int hf_sna_nlp_opti_22_field4 = -1;

static int hf_sna_rh = -1;
static int hf_sna_rh_0 = -1;
static int hf_sna_rh_1 = -1;
static int hf_sna_rh_2 = -1;
static int hf_sna_rh_rri = -1;
static int hf_sna_rh_ru_category = -1;
static int hf_sna_rh_fi = -1;
static int hf_sna_rh_sdi = -1;
static int hf_sna_rh_bci = -1;
static int hf_sna_rh_eci = -1;
static int hf_sna_rh_dr1 = -1;
static int hf_sna_rh_lcci = -1;
static int hf_sna_rh_dr2 = -1;
static int hf_sna_rh_eri = -1;
static int hf_sna_rh_rti = -1;
static int hf_sna_rh_rlwi = -1;
static int hf_sna_rh_qri = -1;
static int hf_sna_rh_pi = -1;
static int hf_sna_rh_bbi = -1;
static int hf_sna_rh_ebi = -1;
static int hf_sna_rh_cdi = -1;
static int hf_sna_rh_csi = -1;
static int hf_sna_rh_edi = -1;
static int hf_sna_rh_pdi = -1;
static int hf_sna_rh_cebi = -1;
/*static int hf_sna_ru = -1;*/

static int hf_sna_gds = -1;
static int hf_sna_gds_len = -1;
static int hf_sna_gds_type = -1;
static int hf_sna_gds_cont = -1;

static int hf_sna_xid = -1;
static int hf_sna_xid_0 = -1;
static int hf_sna_xid_id = -1;
static int hf_sna_xid_format = -1;
static int hf_sna_xid_type = -1;
static int hf_sna_xid_len = -1;
static int hf_sna_xid_idblock = -1;
static int hf_sna_xid_idnum = -1;
static int hf_sna_xid_3_8 = -1;
static int hf_sna_xid_3_init_self = -1;
static int hf_sna_xid_3_stand_bind = -1;
static int hf_sna_xid_3_gener_bind = -1;
static int hf_sna_xid_3_recve_bind = -1;
static int hf_sna_xid_3_actpu = -1;
static int hf_sna_xid_3_nwnode = -1;
static int hf_sna_xid_3_cp = -1;
static int hf_sna_xid_3_cpcp = -1;
static int hf_sna_xid_3_state = -1;
static int hf_sna_xid_3_nonact = -1;
static int hf_sna_xid_3_cpchange = -1;
static int hf_sna_xid_3_10 = -1;
static int hf_sna_xid_3_asend_bind = -1;
static int hf_sna_xid_3_arecv_bind = -1;
static int hf_sna_xid_3_quiesce = -1;
static int hf_sna_xid_3_pucap = -1;
static int hf_sna_xid_3_pbn = -1;
static int hf_sna_xid_3_pacing = -1;
static int hf_sna_xid_3_11 = -1;
static int hf_sna_xid_3_tgshare = -1;
static int hf_sna_xid_3_dedsvc = -1;
static int hf_sna_xid_3_12 = -1;
static int hf_sna_xid_3_negcsup = -1;
static int hf_sna_xid_3_negcomp = -1;
static int hf_sna_xid_3_15 = -1;
static int hf_sna_xid_3_partg = -1;
static int hf_sna_xid_3_dlur = -1;
static int hf_sna_xid_3_dlus = -1;
static int hf_sna_xid_3_exbn = -1;
static int hf_sna_xid_3_genodai = -1;
static int hf_sna_xid_3_branch = -1;
static int hf_sna_xid_3_brnn = -1;
static int hf_sna_xid_3_tg = -1;
static int hf_sna_xid_3_dlc = -1;
static int hf_sna_xid_3_dlen = -1;

static int hf_sna_control_len = -1;
static int hf_sna_control_key = -1;
static int hf_sna_control_hprkey = -1;
static int hf_sna_control_05_delay = -1;
static int hf_sna_control_05_type = -1;
static int hf_sna_control_05_ptp = -1;
static int hf_sna_control_0e_type = -1;
static int hf_sna_control_0e_value = -1;

static gint ett_sna = -1;
static gint ett_sna_th = -1;
static gint ett_sna_th_fid = -1;
static gint ett_sna_nlp_nhdr = -1;
static gint ett_sna_nlp_nhdr_0 = -1;
static gint ett_sna_nlp_nhdr_1 = -1;
static gint ett_sna_nlp_thdr = -1;
static gint ett_sna_nlp_thdr_8 = -1;
static gint ett_sna_nlp_thdr_9 = -1;
static gint ett_sna_nlp_opti_un = -1;
static gint ett_sna_nlp_opti_0d = -1;
static gint ett_sna_nlp_opti_0d_4 = -1;
static gint ett_sna_nlp_opti_0e = -1;
static gint ett_sna_nlp_opti_0e_stat = -1;
static gint ett_sna_nlp_opti_0e_absp = -1;
static gint ett_sna_nlp_opti_0f = -1;
static gint ett_sna_nlp_opti_10 = -1;
static gint ett_sna_nlp_opti_12 = -1;
static gint ett_sna_nlp_opti_14 = -1;
static gint ett_sna_nlp_opti_14_si = -1;
static gint ett_sna_nlp_opti_14_si_2 = -1;
static gint ett_sna_nlp_opti_14_rr = -1;
static gint ett_sna_nlp_opti_14_rr_2 = -1;
static gint ett_sna_nlp_opti_22 = -1;
static gint ett_sna_nlp_opti_22_2 = -1;
static gint ett_sna_nlp_opti_22_3 = -1;
static gint ett_sna_rh = -1;
static gint ett_sna_rh_0 = -1;
static gint ett_sna_rh_1 = -1;
static gint ett_sna_rh_2 = -1;
static gint ett_sna_gds = -1;
static gint ett_sna_xid_0 = -1;
static gint ett_sna_xid_id = -1;
static gint ett_sna_xid_3_8 = -1;
static gint ett_sna_xid_3_10 = -1;
static gint ett_sna_xid_3_11 = -1;
static gint ett_sna_xid_3_12 = -1;
static gint ett_sna_xid_3_15 = -1;
static gint ett_sna_control_un = -1;
static gint ett_sna_control_05 = -1;
static gint ett_sna_control_05hpr = -1;
static gint ett_sna_control_05hpr_type = -1;
static gint ett_sna_control_0e = -1;

static dissector_handle_t data_handle;

/* Defragment fragmented SNA BIUs*/
static gboolean sna_defragment = FALSE;
static GHashTable *sna_fragment_table = NULL;
static GHashTable *sna_reassembled_table = NULL;

/* Format Identifier */
static const value_string sna_th_fid_vals[] = {
      { 0x0,      "SNA device <--> Non-SNA Device" },
      { 0x1,      "Subarea Nodes, without ER or VR" },
      { 0x2,      "Subarea Node <--> PU2" },
      { 0x3,      "Subarea Node or SNA host <--> Subarea Node" },
      { 0x4,      "Subarea Nodes, supporting ER and VR" },
      { 0x5,      "HPR RTP endpoint nodes" },
      { 0xa,      "HPR NLP Frame Routing" },
      { 0xb,      "HPR NLP Frame Routing" },
      { 0xc,      "HPR NLP Automatic Network Routing" },
      { 0xd,      "HPR NLP Automatic Network Routing" },
      { 0xf,      "Adjaced Subarea Nodes, supporting ER and VR" },
      { 0x0,      NULL }
};

/* Mapping Field */
#define MPF_MIDDLE_SEGMENT  0
#define MPF_LAST_SEGMENT    1
#define MPF_FIRST_SEGMENT   2
#define MPF_WHOLE_BIU       3

static const value_string sna_th_mpf_vals[] = {
      { MPF_MIDDLE_SEGMENT,   "Middle segment of a BIU" },
      { MPF_LAST_SEGMENT,     "Last segment of a BIU" },
      { MPF_FIRST_SEGMENT,    "First segment of a BIU" },
      { MPF_WHOLE_BIU,        "Whole BIU" },
      { 0,   NULL }
};

/* Expedited Flow Indicator */
static const value_string sna_th_efi_vals[] = {
      { 0, "Normal Flow" },
      { 1, "Expedited Flow" },
      { 0x0,      NULL }
};

/* Request/Response Indicator */
static const value_string sna_rh_rri_vals[] = {
      { 0, "Request" },
      { 1, "Response" },
      { 0x0,      NULL }
};

/* Request/Response Unit Category */
static const value_string sna_rh_ru_category_vals[] = {
      { 0, "Function Management Data (FMD)" },
      { 1, "Network Control (NC)" },
      { 2, "Data Flow Control (DFC)" },
      { 3, "Session Control (SC)" },
      { 0x0,      NULL }
};

/* Format Indicator */
static const true_false_string sna_rh_fi_truth =
      { "FM Header", "No FM Header" };

/* Sense Data Included */
static const true_false_string sna_rh_sdi_truth =
      { "Included", "Not Included" };

/* Begin Chain Indicator */
static const true_false_string sna_rh_bci_truth =
      { "First in Chain", "Not First in Chain" };

/* End Chain Indicator */
static const true_false_string sna_rh_eci_truth =
      { "Last in Chain", "Not Last in Chain" };

/* Lengith-Checked Compression Indicator */
static const true_false_string sna_rh_lcci_truth =
      { "Compressed", "Not Compressed" };

/* Response Type Indicator */
static const true_false_string sna_rh_rti_truth =
      { "Negative", "Positive" };

/* Queued Response Indicator */
static const true_false_string sna_rh_qri_truth =
      { "Enqueue response in TC queues", "Response bypasses TC queues" };

/* Code Selection Indicator */
static const value_string sna_rh_csi_vals[] = {
      { 0, "EBCDIC" },
      { 1, "ASCII" },
      { 0x0,      NULL }
};

/* TG Sweep */
static const value_string sna_th_tg_sweep_vals[] = {
      { 0, "This PIU may overtake any PU ahead of it." },
      { 1, "This PIU does not ovetake any PIU ahead of it." },
      { 0x0,      NULL }
};

/* ER_VR_SUPP_IND */
static const value_string sna_th_er_vr_supp_ind_vals[] = {
      { 0, "Each node supports ER and VR protocols" },
      { 1, "Includes at least one node that does not support ER and VR"
          " protocols"  },
      { 0x0,      NULL }
};

/* VR_PAC_CNT_IND */
static const value_string sna_th_vr_pac_cnt_ind_vals[] = {
      { 0, "Pacing count on the VR has not reached 0" },
      { 1, "Pacing count on the VR has reached 0" },
      { 0x0,      NULL }
};

/* NTWK_PRTY */
static const value_string sna_th_ntwk_prty_vals[] = {
      { 0, "PIU flows at a lower priority" },
      { 1, "PIU flows at network priority (highest transmission priority)" },
      { 0x0,      NULL }
};

/* TGSF */
static const value_string sna_th_tgsf_vals[] = {
      { 0, "Not segmented" },
      { 1, "Last segment" },
      { 2, "First segment" },
      { 3, "Middle segment" },
      { 0x0,      NULL }
};

/* PIUBF */
static const value_string sna_th_piubf_vals[] = {
      { 0, "Single PIU frame" },
      { 1, "Last PIU of a multiple PIU frame" },
      { 2, "First PIU of a multiple PIU frame" },
      { 3, "Middle PIU of a multiple PIU frame" },
      { 0x0,      NULL }
};

/* NLPOI */
static const value_string sna_th_nlpoi_vals[] = {
      { 0, "NLP starts within this FID4 TH" },
      { 1, "NLP byte 0 starts after RH byte 0 following NLP C/P pad" },
      { 0x0,      NULL }
};

/* TPF */
static const value_string sna_th_tpf_vals[] = {
      { 0, "Low Priority" },
      { 1, "Medium Priority" },
      { 2, "High Priority" },
      { 3, "Network Priority" },
      { 0x0,      NULL }
};

/* VR_CWI */
static const value_string sna_th_vr_cwi_vals[] = {
      { 0, "Increment window size" },
      { 1, "Decrement window size" },
      { 0x0,      NULL }
};

/* TG_NONFIFO_IND */
static const true_false_string sna_th_tg_nonfifo_ind_truth =
      { "TG FIFO is not required", "TG FIFO is required" };

/* VR_SQTI */
static const value_string sna_th_vr_sqti_vals[] = {
      { 0, "Non-sequenced, Non-supervisory" },
      { 1, "Non-sequenced, Supervisory" },
      { 2, "Singly-sequenced" },
      { 0x0,      NULL }
};

/* VRPRQ */
static const true_false_string sna_th_vrprq_truth = {
      "VR pacing request is sent asking for a VR pacing response",
      "No VR pacing response is requested",
};

/* VRPRS */
static const true_false_string sna_th_vrprs_truth = {
      "VR pacing response is sent in response to a VRPRQ bit set",
      "No pacing response sent",
};

/* VR_CWRI */
static const value_string sna_th_vr_cwri_vals[] = {
      { 0, "Increment window size by 1" },
      { 1, "Decrement window size by 1" },
      { 0x0,      NULL }
};

/* VR_RWI */
static const true_false_string sna_th_vr_rwi_truth = {
      "Reset window size to the minimum specified in NC_ACTVR",
      "Do not reset window size",
};

/* Switching Mode */
static const value_string sna_nlp_sm_vals[] = {
      { 5, "Function routing" },
      { 6, "Automatic network routing" },
      { 0x0,      NULL }
};

static const true_false_string sna_nlp_tspi_truth =
      { "Time sensitive", "Not time sensitive" };

static const true_false_string sna_nlp_slowdn1_truth =
      { "Minor congestion", "No minor congestion" };

static const true_false_string sna_nlp_slowdn2_truth =
      { "Major congestion", "No major congestion" };

/* Function Type */
static const value_string sna_nlp_ft_vals[] = {
      { 0x10, "LDLC" },
      { 0x0,      NULL }
};

static const value_string sna_nlp_frh_vals[] = {
      { 0x03, "XID complete request" },
      { 0x04, "XID complete response" },
      { 0x0,      NULL }
};

static const true_false_string sna_nlp_setupi_truth =
      { "Connection setup segment present", "Connection setup segment not"
          " present" };

static const true_false_string sna_nlp_somi_truth =
      { "Start of message", "Not start of message" };

static const true_false_string sna_nlp_eomi_truth =
      { "End of message", "Not end of message" };

static const true_false_string sna_nlp_sri_truth =
      { "Status requested", "No status requested" };

static const true_false_string sna_nlp_rasapi_truth =
      { "Reply as soon as possible", "No need to reply as soon as possible" };

static const true_false_string sna_nlp_retryi_truth =
      { "Undefined", "Sender will retransmit" };

static const true_false_string sna_nlp_lmi_truth =
      { "Last message", "Not last message" };

static const true_false_string sna_nlp_cqfi_truth =
      { "CQFI included", "CQFI not included" };

static const true_false_string sna_nlp_osi_truth =
      { "Optional segments present", "No optional segments present" };

static const value_string sna_xid_3_state_vals[] = {
      { 0x00, "Exchange state indicators not supported" },
      { 0x01, "Negotiation-proceeding exchange" },
      { 0x02, "Prenegotiation exchange" },
      { 0x03, "Nonactivation exchange" },
      { 0x0, NULL }
};

static const value_string sna_xid_3_branch_vals[] = {
      { 0x00, "Sender does not support branch extender" },
      { 0x01, "TG is branch uplink" },
      { 0x02, "TG is branch downlink" },
      { 0x03, "TG is neither uplink nor downlink" },
      { 0x0, NULL }
};

static const value_string sna_xid_type_vals[] = {
      { 0x01, "T1 node" },
      { 0x02, "T2.0 or T2.1 node" },
      { 0x03, "Reserved" },
      { 0x04, "T4 or T5 node" },
      { 0x0, NULL }
};

static const value_string sna_nlp_opti_vals[] = {
      { 0x0d, "Connection Setup Segment" },
      { 0x0e, "Status Segment" },
      { 0x0f, "Client Out Of Band Bits Segment" },
      { 0x10, "Connection Identifier Exchange Segment" },
      { 0x12, "Connection Fault Segment" },
      { 0x14, "Switching Information Segment" },
      { 0x22, "Adaptive Rate-Based Segment" },
      { 0x0, NULL }
};

static const value_string sna_nlp_opti_0d_version_vals[] = {
      { 0x0101, "Version 1.1" },
      { 0x0, NULL }
};

static const value_string sna_nlp_opti_0f_bits_vals[] = {
      { 0x0001, "Request Deactivation" },
      { 0x8000, "Reply - OK" },
      { 0x8004, "Reply - Reject" },
      { 0x0, NULL }
};

static const value_string sna_nlp_opti_22_type_vals[] = {
      { 0x00, "Setup" },
      { 0x01, "Rate Reply" },
      { 0x02, "Rate Request" },
      { 0x03, "Rate Request/Rate Reply" },
      { 0x0, NULL }
};

static const value_string sna_nlp_opti_22_raa_vals[] = {
      { 0x00, "Normal" },
      { 0x01, "Restraint" },
      { 0x02, "Slowdown1" },
      { 0x03, "Slowdown2" },
      { 0x04, "Critical" },
      { 0x0, NULL }
};

static const value_string sna_nlp_opti_22_arb_vals[] = {
      { 0x00, "Base Mode ARB" },
      { 0x01, "Responsive Mode ARB" },
      { 0x0, NULL }
};

/* GDS Variable Type */
static const value_string sna_gds_var_vals[] = {
      { 0x1210, "Change Number Of Sessions" },
      { 0x1211, "Exchange Log Name" },
      { 0x1212, "Control Point Management Services Unit" },
      { 0x1213, "Compare States" },
      { 0x1214, "LU Names Position" },
      { 0x1215, "LU Name" },
      { 0x1217, "Do Know" },
      { 0x1218, "Partner Restart" },
      { 0x1219, "Don't Know" },
      { 0x1220, "Sign-Off" },
      { 0x1221, "Sign-On" },
      { 0x1222, "SNMP-over-SNA" },
      { 0x1223, "Node Address Service" },
      { 0x12C1, "CP Capabilities" },
      { 0x12C2, "Topology Database Update" },
      { 0x12C3, "Register Resource" },
      { 0x12C4, "Locate" },
      { 0x12C5, "Cross-Domain Initiate" },
      { 0x12C9, "Delete Resource" },
      { 0x12CA, "Find Resource" },
      { 0x12CB, "Found Resource" },
      { 0x12CC, "Notify" },
      { 0x12CD, "Initiate-Other Cross-Domain" },
      { 0x12CE, "Route Setup" },
      { 0x12E1, "Error Log" },
      { 0x12F1, "Null Data" },
      { 0x12F2, "User Control Date" },
      { 0x12F3, "Map Name" },
      { 0x12F4, "Error Data" },
      { 0x12F6, "Authentication Token Data" },
      { 0x12F8, "Service Flow Authentication Token Data" },
      { 0x12FF, "Application Data" },
      { 0x1310, "MDS Message Unit" },
      { 0x1311, "MDS Routing Information" },
      { 0x1500, "FID2 Encapsulation" },
      { 0x0,    NULL }
};

/* Control Vector Type */
static const value_string sna_control_vals[] = {
      { 0x00,   "SSCP-LU Session Capabilities Control Vector" },
      { 0x01,   "Date-Time Control Vector" },
      { 0x02,   "Subarea Routing Control Vector" },
      { 0x03,   "SDLC Secondary Station Control Vector" },
      { 0x04,   "LU Control Vector" },
      { 0x05,   "Channel Control Vector" },
      { 0x06,   "Cross-Domain Resource Manager (CDRM) Control Vector" },
      { 0x07,   "PU FMD-RU-Usage Control Vector" },
      { 0x08,   "Intensive Mode Control Vector" },
      { 0x09,   "Activation Request / Response Sequence Identifier Control"
          " Vector" },
      { 0x0a,   "User Request Correlator Control Vector" },
      { 0x0b,   "SSCP-PU Session Capabilities Control Vector" },
      { 0x0c,   "LU-LU Session Capabilities Control Vector" },
      { 0x0d,   "Mode / Class-of-Service / Virtual-Route-Identifier List"
          " Control Vector" },
      { 0x0e,   "Network Name Control Vector" },
      { 0x0f,   "Link Capabilities and Status Control Vector" },
      { 0x10,   "Product Set ID Control Vector" },
      { 0x11,   "Load Module Correlation Control Vector" },
      { 0x12,   "Network Identifier Control Vector" },
      { 0x13,   "Gateway Support Capabilities Control Vector" },
      { 0x14,   "Session Initiation Control Vector" },
      { 0x15,   "Network-Qualified Address Pair Control Vector" },
      { 0x16,   "Names Substitution Control Vector" },
      { 0x17,   "SSCP Identifier Control Vector" },
      { 0x18,   "SSCP Name Control Vector" },
      { 0x19,   "Resource Identifier Control Vector" },
      { 0x1a,   "NAU Address Control Vector" },
      { 0x1b,   "VRID List Control Vector" },
      { 0x1c,   "Network-Qualified Name Pair Control Vector" },
      { 0x1e,   "VR-ER Mapping Data Control Vector" },
      { 0x1f,   "ER Configuration Control Vector" },
      { 0x23,   "Local-Form Session Identifier Control Vector" },
      { 0x24,   "IPL Load Module Request Control Vector" },
      { 0x25,   "Security ID Control Control Vector" },
      { 0x26,   "Network Connection Endpoint Identifier Control Vector" },
      { 0x27,   "XRF Session Activation Control Vector" },
      { 0x28,   "Related Session Identifier Control Vector" },
      { 0x29,   "Session State Data Control Vector" },
      { 0x2a,   "Session Information Control Vector" },
      { 0x2b,   "Route Selection Control Vector" },
      { 0x2c,   "COS/TPF Control Vector" },
      { 0x2d,   "Mode Control Vector" },
      { 0x2f,   "LU Definition Control Vector" },
      { 0x30,   "Assign LU Characteristics Control Vector" },
      { 0x31,   "BIND Image Control Vector" },
      { 0x32,   "Short-Hold Mode Control Vector" },
      { 0x33,   "ENCP Search Control Control Vector" },
      { 0x34,   "LU Definition Override Control Vector" },
      { 0x35,   "Extended Sense Data Control Vector" },
      { 0x36,   "Directory Error Control Vector" },
      { 0x37,   "Directory Entry Correlator Control Vector" },
      { 0x38,   "Short-Hold Mode Emulation Control Vector" },
      { 0x39,   "Network Connection Endpoint (NCE) Instance Identifier"
          " Control Vector" },
      { 0x3a,   "Route Status Data Control Vector" },
      { 0x3b,   "VR Congestion Data Control Vector" },
      { 0x3c,   "Associated Resource Entry Control Vector" },
      { 0x3d,   "Directory Entry Control Vector" },
      { 0x3e,   "Directory Entry Characteristic Control Vector" },
      { 0x3f,   "SSCP (SLU) Capabilities Control Vector" },
      { 0x40,   "Real Associated Resource Control Vector" },
      { 0x41,   "Station Parameters Control Vector" },
      { 0x42,   "Dynamic Path Update Data Control Vector" },
      { 0x43,   "Extended SDLC Station Control Vector" },
      { 0x44,   "Node Descriptor Control Vector" },
      { 0x45,   "Node Characteristics Control Vector" },
      { 0x46,   "TG Descriptor Control Vector" },
      { 0x47,   "TG Characteristics Control Vector" },
      { 0x48,   "Topology Resource Descriptor Control Vector" },
      { 0x49,   "Multinode Persistent Sessions (MNPS) LU Names Control"
          " Vector" },
      { 0x4a,   "Real Owning Control Point Control Vector" },
      { 0x4b,   "RTP Transport Connection Identifier Control Vector" },
      { 0x51,   "DLUR/S Capabilities Control Vector" },
      { 0x52,   "Primary Send Pacing Window Size Control Vector" },
      { 0x56,   "Call Security Verification Control Vector" },
      { 0x57,   "DLC Connection Data Control Vector" },
      { 0x59,   "Installation-Defined CDINIT Data Control Vector" },
      { 0x5a,   "Session Services Extension Support Control Vector" },
      { 0x5b,   "Interchange Node Support Control Vector" },
      { 0x5c,   "APPN Message Transport Control Vector" },
      { 0x5d,   "Subarea Message Transport Control Vector" },
      { 0x5e,   "Related Request Control Vector" },
      { 0x5f,   "Extended Fully Qualified PCID Control Vector" },
      { 0x60,   "Fully Qualified PCID Control Vector" },
      { 0x61,   "HPR Capabilities Control Vector" },
      { 0x62,   "Session Address Control Vector" },
      { 0x63,   "Cryptographic Key Distribution Control Vector" },
      { 0x64,   "TCP/IP Information Control Vector" },
      { 0x65,   "Device Characteristics Control Vector" },
      { 0x66,   "Length-Checked Compression Control Vector" },
      { 0x67,   "Automatic Network Routing (ANR) Path Control Vector" },
      { 0x68,   "XRF/Session Cryptography Control Vector" },
      { 0x69,   "Switched Parameters Control Vector" },
      { 0x6a,   "ER Congestion Data Control Vector" },
      { 0x71,   "Triple DES Cryptography Key Continuation Control Vector" },
      { 0xfe,   "Control Vector Keys Not Recognized" },
      { 0x0,    NULL }
};

static const value_string sna_control_hpr_vals[] = {
      { 0x00,   "Node Identifier Control Vector" },
      { 0x03,   "Network ID Control Vector" },
      { 0x05,   "Network Address Control Vector" },
      { 0x0,    NULL }
};

static const value_string sna_control_0e_type_vals[] = {
      { 0xF1,   "PU Name" },
      { 0xF3,   "LU Name" },
      { 0xF4,   "CP Name" },
      { 0xF5,   "SSCP Name" },
      { 0xF6,   "NNCP Name" },
      { 0xF7,   "Link Station Name" },
      { 0xF8,   "CP Name of CP(PLU)" },
      { 0xF9,   "CP Name of CP(SLU)" },
      { 0xFA,   "Generic Name" },
      { 0x0,    NULL }
};

/* Values to direct the top-most dissector what to dissect
 * after the TH. */
enum next_dissection_enum {
    stop_here,
    rh_only,
    everything
};

enum parse {
    LT,
    KL
};

typedef enum next_dissection_enum next_dissection_t;

static void dissect_xid (tvbuff_t*, packet_info*, proto_tree*, proto_tree*);
static void dissect_fid (tvbuff_t*, packet_info*, proto_tree*, proto_tree*);
static void dissect_nlp (tvbuff_t*, packet_info*, proto_tree*, proto_tree*);
static void dissect_gds (tvbuff_t*, packet_info*, proto_tree*, proto_tree*);
static void dissect_rh (tvbuff_t*, int, proto_tree*);
static void dissect_control(tvbuff_t*, int, int, proto_tree*, int, enum parse);

/* --------------------------------------------------------------------
 * Chapter 2 High-Performance Routing (HPR) Headers
 * --------------------------------------------------------------------
 */

static void
dissect_optional_0d(tvbuff_t *tvb, proto_tree *tree)
{
      int         bits, offset, len, pad;
      proto_tree  *sub_tree;
      proto_item  *sub_ti = NULL;

      if (!tree)
            return;

      proto_tree_add_item(tree, hf_sna_nlp_opti_0d_version, tvb, 2, 2, FALSE);
      bits = tvb_get_guint8(tvb, 4);

      sub_ti = proto_tree_add_uint(tree, hf_sna_nlp_opti_0d_4,
          tvb, 4, 1, bits);
      sub_tree = proto_item_add_subtree(sub_ti, 
          ett_sna_nlp_opti_0d_4);

      proto_tree_add_boolean(sub_tree, hf_sna_nlp_opti_0d_target,
          tvb, 4, 1, bits);
      proto_tree_add_boolean(sub_tree, hf_sna_nlp_opti_0d_arb,
          tvb, 4, 1, bits);
      proto_tree_add_boolean(sub_tree, hf_sna_nlp_opti_0d_reliable,
          tvb, 4, 1, bits);
      proto_tree_add_boolean(sub_tree, hf_sna_nlp_opti_0d_dedicated,
          tvb, 4, 1, bits);

      proto_tree_add_text(tree, tvb, 5, 3, "Reserved");

      offset = 8;

      while (tvb_offset_exists(tvb, offset)) {
            len = tvb_get_guint8(tvb, offset+0);
            if (len) {
                  dissect_control(tvb, offset, len, tree, 1, LT);
                  pad = (len+3) & 0xfffc;
                  if (pad > len)
                        proto_tree_add_text(tree, tvb, offset+len,
                            pad-len, "Padding");
                  offset += pad;
            } else {
                  /* Avoid endless loop */
                  return;
            }
      }
}

static void
dissect_optional_0e(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      int         bits, offset;
      proto_tree  *sub_tree;
      proto_item  *sub_ti = NULL;

      bits = tvb_get_guint8(tvb, 2);
      offset = 20;

      if (tree) {
            sub_ti = proto_tree_add_item(tree, hf_sna_nlp_opti_0e_stat,
                tvb, 2, 1, FALSE);
            sub_tree = proto_item_add_subtree(sub_ti, 
                ett_sna_nlp_opti_0e_stat);

            proto_tree_add_boolean(sub_tree, hf_sna_nlp_opti_0e_gap,
                tvb, 2, 1, bits);
            proto_tree_add_boolean(sub_tree, hf_sna_nlp_opti_0e_idle,
                tvb, 2, 1, bits);
            proto_tree_add_item(tree, hf_sna_nlp_opti_0e_nabsp,
                tvb, 3, 1, FALSE);
            proto_tree_add_item(tree, hf_sna_nlp_opti_0e_sync,
                tvb, 4, 2, FALSE);
            proto_tree_add_item(tree, hf_sna_nlp_opti_0e_echo,
                tvb, 6, 2, FALSE);
            proto_tree_add_item(tree, hf_sna_nlp_opti_0e_rseq,
                tvb, 8, 4, FALSE);
            proto_tree_add_text(tree, tvb, 12, 8, "Reserved");

            if (tvb_offset_exists(tvb, offset))
                  call_dissector(data_handle,
                      tvb_new_subset(tvb, 4, -1, -1), pinfo, tree);
      }
      if (bits & 0x40) {
            if (check_col(pinfo->cinfo, COL_INFO))
                  col_add_str(pinfo->cinfo, COL_INFO,
                      "HPR Idle Message");
      } else {
            if (check_col(pinfo->cinfo, COL_INFO))
                  col_add_str(pinfo->cinfo, COL_INFO,
                      "HPR Status Message");
      }
}

static void
dissect_optional_0f(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      if (!tree)
            return;

      proto_tree_add_item(tree, hf_sna_nlp_opti_0f_bits, tvb, 2, 2, FALSE);
      if (tvb_offset_exists(tvb, 4))
            call_dissector(data_handle,
                tvb_new_subset(tvb, 4, -1, -1), pinfo, tree);
}

static void
dissect_optional_10(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      if (!tree)
            return;

      proto_tree_add_text(tree, tvb, 2, 2, "Reserved");
      proto_tree_add_item(tree, hf_sna_nlp_opti_10_tcid, tvb, 4, 8, FALSE);
      if (tvb_offset_exists(tvb, 12))
            call_dissector(data_handle,
                tvb_new_subset(tvb, 12, -1, -1), pinfo, tree);
}

static void
dissect_optional_12(tvbuff_t *tvb, proto_tree *tree)
{
      if (!tree)
            return;

      proto_tree_add_text(tree, tvb, 2, 2, "Reserved");
      proto_tree_add_item(tree, hf_sna_nlp_opti_12_sense, tvb, 4, -1, FALSE);
}

static void
dissect_optional_14(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      proto_tree  *sub_tree, *bf_tree;
      proto_item  *sub_item, *bf_item;
      int         len, pad, type, bits, offset, num, sublen;

      if (!tree)
            return;

      proto_tree_add_text(tree, tvb, 2, 2, "Reserved");

      offset = 4;

      len = tvb_get_guint8(tvb, offset);
      type = tvb_get_guint8(tvb, offset+1);

      if ((type != 0x83) || (len <= 16)) {
            /* Invalid */
            call_dissector(data_handle,
                tvb_new_subset(tvb, offset, -1, -1), pinfo, tree);
            return;
      }
      sub_item = proto_tree_add_text(tree, tvb, offset, len,
          "Switching Information Control Vector");
      sub_tree = proto_item_add_subtree(sub_item, ett_sna_nlp_opti_14_si);

      proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_14_si_len,
          tvb, offset, 1, len);
      proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_14_si_key,
          tvb, offset+1, 1, type);
      
      bits = tvb_get_guint8(tvb, offset+2);
      bf_item = proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_14_si_2,
          tvb, offset+2, 1, bits);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_opti_14_si_2);

      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_14_si_refifo,
          tvb, offset+2, 1, bits);
      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_14_si_mobility,
          tvb, offset+2, 1, bits);
      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_14_si_dirsearch,
          tvb, offset+2, 1, bits);
      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_14_si_limitres,
          tvb, offset+2, 1, bits);
      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_14_si_ncescope,
          tvb, offset+2, 1, bits);
      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_14_si_mnpsrscv,
          tvb, offset+2, 1, bits);

      proto_tree_add_text(sub_tree, tvb, offset+3, 1, "Reserved");
      proto_tree_add_item(sub_tree, hf_sna_nlp_opti_14_si_maxpsize,
          tvb, offset+4, 4, FALSE);
      proto_tree_add_item(sub_tree, hf_sna_nlp_opti_14_si_switch,
          tvb, offset+8, 4, FALSE);
      proto_tree_add_item(sub_tree, hf_sna_nlp_opti_14_si_alive,
          tvb, offset+12, 4, FALSE);

      dissect_control(tvb, offset+16, len-16, sub_tree, 1, LT);

      pad = (len+3) & 0xfffc;
      if (pad > len)
            proto_tree_add_text(sub_tree, tvb, offset+len, pad-len,
                "Padding");
      offset += pad;

      len = tvb_get_guint8(tvb, offset);
      type = tvb_get_guint8(tvb, offset+1);

      if ((type != 0x85) || ( len < 4))  {
            /* Invalid */
            call_dissector(data_handle,
                tvb_new_subset(tvb, offset, -1, -1), pinfo, tree);
            return;
      }
      sub_item = proto_tree_add_text(tree, tvb, offset, len,
          "Return Route TG Descriptor Control Vector");
      sub_tree = proto_item_add_subtree(sub_item, ett_sna_nlp_opti_14_rr);

      proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_14_rr_len,
          tvb, offset, 1, len);
      proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_14_rr_key,
          tvb, offset+1, 1, type);
      
      bits = tvb_get_guint8(tvb, offset+2);
      bf_item = proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_14_rr_2,
          tvb, offset+2, 1, bits);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_opti_14_rr_2);

      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_14_rr_bfe,
          tvb, offset+2, 1, bits);

      num = tvb_get_guint8(tvb, offset+3);

      proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_14_rr_num,
          tvb, offset+3, 1, num);

      offset += 4;

      while (num) {
            sublen = tvb_get_guint8(tvb, offset);
            if (sublen) {
                  dissect_control(tvb, offset, sublen, sub_tree, 1, LT);
            } else {
                  /* Invalid */
                  call_dissector(data_handle,
                      tvb_new_subset(tvb, offset, -1, -1), pinfo, tree);
                  return;
            }
            /* No padding here */
            offset += sublen;
            num--;
      }
}

static void
dissect_optional_22(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      int         bits, type;

      if (!tree)
            return;

      bits = tvb_get_guint8(tvb, 2);
      type = (bits & 0xc0) >> 6;

      bf_item = proto_tree_add_uint(tree, hf_sna_nlp_opti_22_2,
          tvb, 2, 1, bits);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_opti_22_2);

      proto_tree_add_uint(bf_tree, hf_sna_nlp_opti_22_type,
          tvb, 2, 1, bits);
      proto_tree_add_uint(bf_tree, hf_sna_nlp_opti_22_raa,
          tvb, 2, 1, bits);
      proto_tree_add_boolean(bf_tree, hf_sna_nlp_opti_22_parity,
          tvb, 2, 1, bits);
      proto_tree_add_uint(bf_tree, hf_sna_nlp_opti_22_arb,
          tvb, 2, 1, bits);

      bits = tvb_get_guint8(tvb, 3);

      bf_item = proto_tree_add_uint(tree, hf_sna_nlp_opti_22_3,
          tvb, 3, 1, bits);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_opti_22_3);

      proto_tree_add_uint(bf_tree, hf_sna_nlp_opti_22_ratereq,
          tvb, 3, 1, bits);
      proto_tree_add_uint(bf_tree, hf_sna_nlp_opti_22_raterep,
          tvb, 3, 1, bits);

      proto_tree_add_item(tree, hf_sna_nlp_opti_22_field1,
          tvb, 4, 4, FALSE);
      proto_tree_add_item(tree, hf_sna_nlp_opti_22_field2,
          tvb, 8, 4, FALSE);

      if (type == 0) {
            proto_tree_add_item(tree, hf_sna_nlp_opti_22_field3,
                tvb, 12, 4, FALSE);
            proto_tree_add_item(tree, hf_sna_nlp_opti_22_field4,
                tvb, 16, 4, FALSE);

            if (tvb_offset_exists(tvb, 20))
                  call_dissector(data_handle,
                      tvb_new_subset(tvb, 20, -1, -1), pinfo, tree);
      } else {
            if (tvb_offset_exists(tvb, 12))
                  call_dissector(data_handle,
                      tvb_new_subset(tvb, 12, -1, -1), pinfo, tree);
      }
}

static void
dissect_optional(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      proto_tree  *sub_tree;
      proto_item  *sub_item;
      int         offset, type, len;
      gint        ett;

      sub_tree = NULL;

      offset = 0;

      while (tvb_offset_exists(tvb, offset)) {
            len = tvb_get_guint8(tvb, offset);
            type = tvb_get_guint8(tvb, offset+1);

            /* Prevent loop for invalid crap in packet */
            if (len == 0) {
                  if (tree)
                        call_dissector(data_handle,
                            tvb_new_subset(tvb, offset,
                            -1, -1), pinfo, tree);
                  return;
            }
                  
            ett = ett_sna_nlp_opti_un;
            if(type == 0x0d) ett = ett_sna_nlp_opti_0d;
            if(type == 0x0e) ett = ett_sna_nlp_opti_0e;
            if(type == 0x0f) ett = ett_sna_nlp_opti_0f;
            if(type == 0x10) ett = ett_sna_nlp_opti_10;
            if(type == 0x12) ett = ett_sna_nlp_opti_12;
            if(type == 0x14) ett = ett_sna_nlp_opti_14;
            if(type == 0x22) ett = ett_sna_nlp_opti_22;
            if (tree) {
                  sub_item = proto_tree_add_text(tree, tvb,
                      offset, len << 2,
                      val_to_str(type, sna_nlp_opti_vals,
                      "Unknown Segment Type"));
                  sub_tree = proto_item_add_subtree(sub_item, ett);
                  proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_len,
                      tvb, offset, 1, len);
                  proto_tree_add_uint(sub_tree, hf_sna_nlp_opti_type,
                      tvb, offset+1, 1, type);
            }
            switch(type) {
                  case 0x0d:
                        dissect_optional_0d(tvb_new_subset(tvb, offset,
                            len << 2, -1), sub_tree);
                        break;
                  case 0x0e:
                        dissect_optional_0e(tvb_new_subset(tvb, offset,
                            len << 2, -1), pinfo, sub_tree);
                        break;
                  case 0x0f:
                        dissect_optional_0f(tvb_new_subset(tvb, offset,
                            len << 2, -1), pinfo, sub_tree);
                        break;
                  case 0x10:
                        dissect_optional_10(tvb_new_subset(tvb, offset,
                            len << 2, -1), pinfo, sub_tree);
                        break;
                  case 0x12:
                        dissect_optional_12(tvb_new_subset(tvb, offset,
                            len << 2, -1), sub_tree);
                        break;
                  case 0x14:
                        dissect_optional_14(tvb_new_subset(tvb, offset,
                            len << 2, -1), pinfo, sub_tree);
                        break;
                  case 0x22:
                        dissect_optional_22(tvb_new_subset(tvb, offset,
                            len << 2, -1), pinfo, sub_tree);
                        break;
                  default:
                        call_dissector(data_handle,
                            tvb_new_subset(tvb, offset,
                            len << 2, -1), pinfo, sub_tree);
            }
            offset += (len << 2);
      }
}

static void
dissect_nlp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
    proto_tree *parent_tree)
{
      proto_tree  *nlp_tree, *bf_tree;
      proto_item  *nlp_item, *bf_item, *h_item;
      guint8            nhdr_0, nhdr_1, nhdr_x, thdr_8, thdr_9, fid;
      guint32           thdr_len, thdr_dlf;
      guint16           subindex;

      int index = 0, counter = 0;

      nlp_tree = NULL;
      nlp_item = NULL;

      nhdr_0 = tvb_get_guint8(tvb, index);
      nhdr_1 = tvb_get_guint8(tvb, index+1);

      if (check_col(pinfo->cinfo, COL_INFO))
            col_add_str(pinfo->cinfo, COL_INFO, "HPR NLP Packet");

      if (tree) {
            /* Don't bother setting length. We'll set it later after we
             * find the lengths of NHDR */
            nlp_item = proto_tree_add_item(tree, hf_sna_nlp_nhdr, tvb,
                index, -1, FALSE);
            nlp_tree = proto_item_add_subtree(nlp_item, ett_sna_nlp_nhdr);

            bf_item = proto_tree_add_uint(nlp_tree, hf_sna_nlp_nhdr_0, tvb,
                index, 1, nhdr_0);
            bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_nhdr_0);

            proto_tree_add_uint(bf_tree, hf_sna_nlp_sm, tvb, index, 1,
                nhdr_0);
            proto_tree_add_uint(bf_tree, hf_sna_nlp_tpf, tvb, index, 1,
                nhdr_0);

            bf_item = proto_tree_add_uint(nlp_tree, hf_sna_nlp_nhdr_1, tvb,
                index+1, 1, nhdr_1);
            bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_nhdr_1);

            proto_tree_add_uint(bf_tree, hf_sna_nlp_ft, tvb,
                index+1, 1, nhdr_1);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_tspi, tvb,
                index+1, 1, nhdr_1);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_slowdn1, tvb,
                index+1, 1, nhdr_1);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_slowdn2, tvb,
                index+1, 1, nhdr_1);
      }
      /* ANR or FR lists */

      index += 2;
      counter = 0;

      if ((nhdr_0 & 0xe0) == 0xa0) {
            do {
                  nhdr_x = tvb_get_guint8(tvb, index + counter);
                  counter ++;
            } while (nhdr_x != 0xff);
            if (tree)
                  h_item = proto_tree_add_item(nlp_tree, 
                      hf_sna_nlp_fra, tvb, index, counter, FALSE);
            index += counter;
            if (tree)
                  proto_tree_add_text(nlp_tree, tvb, index, 1,
                      "Reserved");
            index++;

            if (tree)
                  proto_item_set_len(nlp_item, index);

            if ((nhdr_1 & 0xf0) == 0x10) {
                  nhdr_x = tvb_get_guint8(tvb, index);
                  if (tree)
                        proto_tree_add_uint(tree, hf_sna_nlp_frh, 
                            tvb, index, 1, nhdr_x);
                  index ++;

                  if (tvb_offset_exists(tvb, index))
                        call_dissector(data_handle,
                              tvb_new_subset(tvb, index, -1, -1),
                              pinfo, parent_tree);
                  return;
            }
      }
      if ((nhdr_0 & 0xe0) == 0xc0) {
            do {
                  nhdr_x = tvb_get_guint8(tvb, index + counter);
                  counter ++;
            } while (nhdr_x != 0xff);
            if (tree)
                  h_item = proto_tree_add_item(nlp_tree, hf_sna_nlp_anr, 
                      tvb, index, counter, FALSE);
            index += counter;

            if (tree)
                  proto_tree_add_text(nlp_tree, tvb, index, 1,
                      "Reserved");
            index++;

            if (tree)
                  proto_item_set_len(nlp_item, index);
      }

      thdr_8 = tvb_get_guint8(tvb, index+8);
      thdr_9 = tvb_get_guint8(tvb, index+9);
      thdr_len = tvb_get_ntohs(tvb, index+10);
      thdr_dlf = tvb_get_ntohl(tvb, index+12);

      if (tree) {
            nlp_item = proto_tree_add_item(tree, hf_sna_nlp_thdr, tvb, 
                index, thdr_len << 2, FALSE);
            nlp_tree = proto_item_add_subtree(nlp_item, ett_sna_nlp_thdr);

            proto_tree_add_item(nlp_tree, hf_sna_nlp_tcid, tvb,
                index, 8, FALSE);
            bf_item = proto_tree_add_uint(nlp_tree, hf_sna_nlp_thdr_8, tvb,
                index+8, 1, thdr_8);
            bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_thdr_8);

            proto_tree_add_boolean(bf_tree, hf_sna_nlp_setupi, tvb,
                index+8, 1, thdr_8);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_somi, tvb, index+8,
                1, thdr_8);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_eomi, tvb, index+8,
                1, thdr_8);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_sri, tvb, index+8,
                1, thdr_8);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_rasapi, tvb,
                index+8, 1, thdr_8);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_retryi, tvb,
                index+8, 1, thdr_8);

            bf_item = proto_tree_add_uint(nlp_tree, hf_sna_nlp_thdr_9, tvb,
                index+9, 1, thdr_9);
            bf_tree = proto_item_add_subtree(bf_item, ett_sna_nlp_thdr_9);

            proto_tree_add_boolean(bf_tree, hf_sna_nlp_lmi, tvb, index+9,
                1, thdr_9);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_cqfi, tvb, index+9,
                1, thdr_9);
            proto_tree_add_boolean(bf_tree, hf_sna_nlp_osi, tvb, index+9,
                1, thdr_9);

            proto_tree_add_uint(nlp_tree, hf_sna_nlp_offset, tvb, index+10,
                2, thdr_len);
            proto_tree_add_uint(nlp_tree, hf_sna_nlp_dlf, tvb, index+12,
                4, thdr_dlf);
            proto_tree_add_item(nlp_tree, hf_sna_nlp_bsn, tvb, index+16,
                4, FALSE);
      }
      subindex = 20;

      if (((thdr_9 & 0x18) == 0x08) && ((thdr_len << 2) > subindex)) {
            counter = tvb_get_guint8(tvb, index + subindex);
            if (tvb_get_guint8(tvb, index+subindex+1) == 5)
                  dissect_control(tvb, index + subindex, counter+2, nlp_tree, 1, LT);
            else
                  call_dissector(data_handle,
                      tvb_new_subset(tvb, index + subindex, counter+2,
                      -1), pinfo, nlp_tree);

            subindex += (counter+2);
      }
      if ((thdr_9 & 0x04) && ((thdr_len << 2) > subindex))
            dissect_optional(
                tvb_new_subset(tvb, index + subindex,
                (thdr_len << 2) - subindex, -1),
                pinfo, nlp_tree);

      index += (thdr_len << 2);
      if (((thdr_8 & 0x20) == 0) && thdr_dlf) {
            if (check_col(pinfo->cinfo, COL_INFO))
                  col_add_str(pinfo->cinfo, COL_INFO, "HPR Fragment");
            if (tvb_offset_exists(tvb, index)) {
                  call_dissector(data_handle,
                      tvb_new_subset(tvb, index, -1, -1), pinfo,
                      parent_tree);
            }
            return;
      }
      if (tvb_offset_exists(tvb, index)) {
            /* Transmission Header Format Identifier */
            fid = hi_nibble(tvb_get_guint8(tvb, index));
            if (fid == 5) /* Only FID5 allowed for HPR */
                  dissect_fid(tvb_new_subset(tvb, index, -1, -1), pinfo,
                      tree, parent_tree);
            else {
                  if (tvb_get_ntohs(tvb, index+2) == 0x12ce) {
                        /* Route Setup */
                        if (check_col(pinfo->cinfo, COL_INFO))
                              col_add_str(pinfo->cinfo, COL_INFO,
                                  "HPR Route Setup");
                        dissect_gds(tvb_new_subset(tvb, index, -1, -1),
                            pinfo, tree, parent_tree);
                  } else
                        call_dissector(data_handle, 
                            tvb_new_subset(tvb, index, -1, -1),
                            pinfo, parent_tree);
            }
      }
}

/* --------------------------------------------------------------------
 * Chapter 3 Exchange Identification (XID) Information Fields
 * --------------------------------------------------------------------
 */

static void
dissect_xid1(tvbuff_t *tvb, proto_tree *tree)
{
      if (!tree)
            return;

      proto_tree_add_text(tree, tvb, 0, 2, "Reserved");

}

static void
dissect_xid2(tvbuff_t *tvb, proto_tree *tree)
{
      guint       dlen, offset;

      if (!tree)
            return;

      dlen = tvb_get_guint8(tvb, 0);

      offset = dlen;

      while (tvb_offset_exists(tvb, offset)) {
            dlen = tvb_get_guint8(tvb, offset+1);
            dissect_control(tvb, offset, dlen+2, tree, 0, KL);
            offset += (dlen + 2);
      }
}

static void
dissect_xid3(tvbuff_t *tvb, proto_tree *tree)
{
      proto_tree  *sub_tree;
      proto_item  *sub_ti = NULL;
      guint       val, dlen, offset;

      if (!tree)
            return;

      proto_tree_add_text(tree, tvb, 0, 2, "Reserved");

      val = tvb_get_ntohs(tvb, 2);

      sub_ti = proto_tree_add_uint(tree, hf_sna_xid_3_8, tvb,
          2, 2, val);
      sub_tree = proto_item_add_subtree(sub_ti, ett_sna_xid_3_8);

      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_init_self, tvb, 2, 2,
          val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_stand_bind, tvb, 2, 2,
          val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_gener_bind, tvb, 2, 2,
          val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_recve_bind, tvb, 2, 2,
          val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_actpu, tvb, 2, 2, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_nwnode, tvb, 2, 2, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_cp, tvb, 2, 2, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_cpcp, tvb, 2, 2, val);
      proto_tree_add_uint(sub_tree, hf_sna_xid_3_state, tvb, 2, 2, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_nonact, tvb, 2, 2, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_cpchange, tvb, 2, 2,
          val);

      val = tvb_get_guint8(tvb, 4);

      sub_ti = proto_tree_add_uint(tree, hf_sna_xid_3_10, tvb,
          4, 1, val);
      sub_tree = proto_item_add_subtree(sub_ti, ett_sna_xid_3_10);

      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_asend_bind, tvb, 4, 1,
          val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_arecv_bind, tvb, 4, 1,
          val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_quiesce, tvb, 4, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_pucap, tvb, 4, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_pbn, tvb, 4, 1, val);
      proto_tree_add_uint(sub_tree, hf_sna_xid_3_pacing, tvb, 4, 1, val);

      val = tvb_get_guint8(tvb, 5);

      sub_ti = proto_tree_add_uint(tree, hf_sna_xid_3_11, tvb,
          5, 1, val);
      sub_tree = proto_item_add_subtree(sub_ti, ett_sna_xid_3_11);

      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_tgshare, tvb, 5, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_dedsvc, tvb, 5, 1, val);

      val = tvb_get_guint8(tvb, 6);

      sub_ti = proto_tree_add_item(tree, hf_sna_xid_3_12, tvb,
          6, 1, FALSE);
      sub_tree = proto_item_add_subtree(sub_ti, ett_sna_xid_3_12);

      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_negcsup, tvb, 6, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_negcomp, tvb, 6, 1, val);

      proto_tree_add_text(tree, tvb, 7, 2, "Reserved");

      val = tvb_get_guint8(tvb, 9);

      sub_ti = proto_tree_add_item(tree, hf_sna_xid_3_15, tvb,
          9, 1, FALSE);
      sub_tree = proto_item_add_subtree(sub_ti, ett_sna_xid_3_15);

      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_partg, tvb, 9, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_dlur, tvb, 9, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_dlus, tvb, 9, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_exbn, tvb, 9, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_genodai, tvb, 9, 1, val);
      proto_tree_add_uint(sub_tree, hf_sna_xid_3_branch, tvb, 9, 1, val);
      proto_tree_add_boolean(sub_tree, hf_sna_xid_3_brnn, tvb, 9, 1, val);

      proto_tree_add_item(tree, hf_sna_xid_3_tg, tvb, 10, 1, FALSE);
      proto_tree_add_item(tree, hf_sna_xid_3_dlc, tvb, 11, 1, FALSE);

      dlen = tvb_get_guint8(tvb, 12);

      proto_tree_add_uint(tree, hf_sna_xid_3_dlen, tvb, 12, 1, dlen);

      /* FIXME: DLC Dependent Data Go Here */

      offset = 12 + dlen;

      while (tvb_offset_exists(tvb, offset)) {
            dlen = tvb_get_guint8(tvb, offset+1);
            dissect_control(tvb, offset, dlen+2, tree, 0, KL);
            offset += (dlen+2);
      }
}

static void
dissect_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
    proto_tree *parent_tree)
{
      proto_tree  *sub_tree;
      proto_item  *sub_ti = NULL;
      int         format, type, len;
      guint32           id;

      len = tvb_get_guint8(tvb, 1);
      type = tvb_get_guint8(tvb, 0);
      id = tvb_get_ntohl(tvb, 2);
      format = hi_nibble(type);

      /* Summary information */
      if (check_col(pinfo->cinfo, COL_INFO))
            col_add_fstr(pinfo->cinfo, COL_INFO,
                "SNA XID Format:%d Type:%s", format,
                val_to_str(lo_nibble(type), sna_xid_type_vals,
                "Unknown Type"));

      if (tree) {
            sub_ti = proto_tree_add_item(tree, hf_sna_xid_0, tvb,
                0, 1, FALSE);
            sub_tree = proto_item_add_subtree(sub_ti, ett_sna_xid_0);

            proto_tree_add_uint(sub_tree, hf_sna_xid_format, tvb, 0, 1,
                type);
            proto_tree_add_uint(sub_tree, hf_sna_xid_type, tvb, 0, 1,
                type);

            proto_tree_add_uint(tree, hf_sna_xid_len, tvb, 1, 1, len);

            sub_ti = proto_tree_add_item(tree, hf_sna_xid_id, tvb,
                2, 4, FALSE);
            sub_tree = proto_item_add_subtree(sub_ti, ett_sna_xid_id);

            proto_tree_add_uint(sub_tree, hf_sna_xid_idblock, tvb, 2, 4,
                id);
            proto_tree_add_uint(sub_tree, hf_sna_xid_idnum, tvb, 2, 4,
                id);

            switch(format) {
                  case 0:
                        break;
                  case 1:
                        dissect_xid1(tvb_new_subset(tvb, 6, len-6, -1),
                            tree);
                        break;
                  case 2:
                        dissect_xid2(tvb_new_subset(tvb, 6, len-6, -1),
                            tree);
                        break;
                  case 3:
                        dissect_xid3(tvb_new_subset(tvb, 6, len-6, -1),
                            tree);
                        break;
                  default:
                        /* external standards organizations */
                        call_dissector(data_handle,
                            tvb_new_subset(tvb, 6, len-6, -1),
                            pinfo, tree);
            }
      }

      if (format == 0)
            len = 6;

      if (tvb_offset_exists(tvb, len))
            call_dissector(data_handle,
                tvb_new_subset(tvb, len, -1, -1), pinfo, parent_tree);
}

/* --------------------------------------------------------------------
 * Chapter 4 Transmission Headers (THs)
 * --------------------------------------------------------------------
 */

#define RH_LEN    3

static unsigned int
mpf_value(guint8 th_byte)
{
      return (th_byte & 0x0c) >> 2;
}

#define FIRST_FRAG_NUMBER     0
#define MIDDLE_FRAG_NUMBER    1
#define LAST_FRAG_NUMBER      2

/* FID2 is defragged by sequence. The weird thing is that we have neither
 * absolute sequence numbers, nor byte offets. Other FIDs have byte offsets
 * (the DCF field), but not FID2. The only thing we have to go with is "FIRST",
 * "MIDDLE", or "LAST". If the BIU is split into 3 frames, then everything is
 * fine, * "FIRST", "MIDDLE", and "LAST" map nicely onto frag-number 0, 1,
 * and 2. However, if the BIU is split into 2 frames, then we only have
 * "FIRST" and "LAST", and the mapping *should* be frag-number 0 and 1,
 * *NOT* 0 and 2.
 *
 * The SNA docs say "FID2 PIUs cannot be blocked because there is no DCF in the
 * TH format for deblocking" (note on Figure 4-2 in the IBM SNA documention,
 * see the FTP URL in the comment near the top of this file). I *think*
 * this means that the fragmented frames cannot arrive out of order.
 * Well, I *want* it to mean this, because w/o this limitation, if you
 * get a "FIRST" frame and a "LAST" frame, how long should you wait to
 * see if a "MIDDLE" frame every arrives????? Thus, if frames *have* to
 * arrive in order, then we're saved.
 *
 * The problem then boils down to figuring out if "LAST" means frag-number 1
 * (in the case of a BIU split into 2 frames) or frag-number 2
 * (in the case of a BIU split into 3 frames).
 *
 * Assuming fragmented FID2 BIU frames *do* arrive in order, the obvious
 * way to handle the mapping of "LAST" to either frag-number 1 or
 * frag-number 2 is to keep a hash which tracks the frames seen, etc.
 * This consumes resources. A trickier way, but a way which works, is to
 * always map the "LAST" BIU segment to frag-number 2. Here's the trickery:
 * if we add frag-number 2, which we know to be the "LAST" BIU segment,
 * and the reassembly code tells us that the the BIU is still not reassmebled,
 * then, owing to the, ahem, /fact/, that fragmented BIU segments arrive
 * in order :), we know that 1) "FIRST" did come, and 2) there's no "MIDDLE",
 * because this BIU was fragmented into 2 frames, not 3. So, we'll be
 * tricky and add a zero-length "MIDDLE" BIU frame (i.e, frag-number 1)
 * to complete the reassembly.
 */
static tvbuff_t*
defragment_by_sequence(packet_info *pinfo, tvbuff_t *tvb, int offset, int mpf,
    int id)
{
      fragment_data *fd_head;
      int frag_number = -1;
      int more_frags = TRUE;
      tvbuff_t *rh_tvb = NULL;
      gint frag_len;

      /* Determine frag_number and more_frags */
      switch(mpf) {
            case MPF_WHOLE_BIU:
                  /* nothing */
                  break;
            case MPF_FIRST_SEGMENT:
                  frag_number = FIRST_FRAG_NUMBER;
                  break;
            case MPF_MIDDLE_SEGMENT:
                  frag_number = MIDDLE_FRAG_NUMBER;
                  break;
            case MPF_LAST_SEGMENT:
                  frag_number = LAST_FRAG_NUMBER;
                  more_frags = FALSE;
                  break;
            default:
                  g_assert_not_reached();
      }

      /* If sna_defragment is on, and this is a fragment.. */
      if (frag_number > -1) {
            /* XXX - check length ??? */
            frag_len = tvb_reported_length_remaining(tvb, offset);
            if (tvb_bytes_exist(tvb, offset, frag_len)) {
                  fd_head = fragment_add_seq(tvb, offset, pinfo, id,
                      sna_fragment_table, frag_number, frag_len,
                      more_frags);

                  /* We added the LAST segment and reassembly didn't
                   * complete. Insert a zero-length MIDDLE segment to
                   * turn a 2-frame BIU-fragmentation into a 3-frame
                   * BIU-fragmentation (empty middle frag).
                     * See above long comment about this trickery. */

                  if (mpf == MPF_LAST_SEGMENT && !fd_head) {
                        fd_head = fragment_add_seq(tvb, offset, pinfo,
                            id, sna_fragment_table,
                            MIDDLE_FRAG_NUMBER, 0, TRUE);
                  }

                  if (fd_head != NULL) {
                        /* We have the complete reassembled payload. */
                        rh_tvb = tvb_new_real_data(fd_head->data,
                            fd_head->len, fd_head->len);

                        /* Add the tvbuff to the chain of tvbuffs
                         * so that it will get cleaned up too. */
                        tvb_set_child_real_data_tvbuff(tvb, rh_tvb);

                        /* Add the defragmented data to the data
                         * source list. */
                        add_new_data_source(pinfo, rh_tvb,
                            "Reassembled SNA BIU");
                  }
            }
      }
      return rh_tvb;
}

#define SNA_FID01_ADDR_LEN    2

/* FID Types 0 and 1 */
static int
dissect_fid0_1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      guint8            th_0;
      const guint8      *ptr;

      const int bytes_in_header = 10;

      if (tree) {
            /* Byte 0 */
            th_0 = tvb_get_guint8(tvb, 0);
            bf_item = proto_tree_add_uint(tree, hf_sna_th_0, tvb, 0, 1,
                th_0);
            bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

            proto_tree_add_uint(bf_tree, hf_sna_th_fid, tvb, 0, 1, th_0);
            proto_tree_add_uint(bf_tree, hf_sna_th_mpf, tvb, 0, 1, th_0);
            proto_tree_add_uint(bf_tree, hf_sna_th_efi, tvb, 0, 1, th_0);

            /* Byte 1 */
            proto_tree_add_text(tree, tvb, 1, 1, "Reserved");

            /* Bytes 2-3 */
            proto_tree_add_item(tree, hf_sna_th_daf, tvb, 2, 2, FALSE);
      }

      /* Set DST addr */
      ptr = tvb_get_ptr(tvb, 2, SNA_FID01_ADDR_LEN);
      SET_ADDRESS(&pinfo->net_dst, AT_SNA, SNA_FID01_ADDR_LEN, ptr);
      SET_ADDRESS(&pinfo->dst, AT_SNA, SNA_FID01_ADDR_LEN, ptr);

      if (tree)
            proto_tree_add_item(tree, hf_sna_th_oaf, tvb, 4, 2, FALSE);

      /* Set SRC addr */
      ptr = tvb_get_ptr(tvb, 4, SNA_FID01_ADDR_LEN);
      SET_ADDRESS(&pinfo->net_src, AT_SNA, SNA_FID01_ADDR_LEN, ptr);
      SET_ADDRESS(&pinfo->src, AT_SNA, SNA_FID01_ADDR_LEN, ptr);

      /* If we're not filling a proto_tree, return now */
      if (tree)
            return bytes_in_header;

      proto_tree_add_item(tree, hf_sna_th_snf, tvb, 6, 2, FALSE);
      proto_tree_add_item(tree, hf_sna_th_dcf, tvb, 8, 2, FALSE);

      return bytes_in_header;
}

#define SNA_FID2_ADDR_LEN     1

/* FID Type 2 */
static int
dissect_fid2(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
        tvbuff_t **rh_tvb_ptr, next_dissection_t *continue_dissecting)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      guint8            th_0=0, daf=0, oaf=0;
      const guint8      *ptr;
      unsigned int      mpf, id;

      const int bytes_in_header = 6;

      th_0 = tvb_get_guint8(tvb, 0);
      mpf = mpf_value(th_0);

      if (tree) {
            daf = tvb_get_guint8(tvb, 2);
            oaf = tvb_get_guint8(tvb, 3);

            /* Byte 0 */
            bf_item = proto_tree_add_uint(tree, hf_sna_th_0, tvb, 0, 1,
                th_0);
            bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

            proto_tree_add_uint(bf_tree, hf_sna_th_fid, tvb, 0, 1, th_0);
            proto_tree_add_uint(bf_tree, hf_sna_th_mpf, tvb, 0, 1, th_0);
            proto_tree_add_uint(bf_tree, hf_sna_th_odai,tvb, 0, 1, th_0);
            proto_tree_add_uint(bf_tree, hf_sna_th_efi, tvb, 0, 1, th_0);


            /* Byte 1 */
            proto_tree_add_text(tree, tvb, 1, 1, "Reserved");

            /* Byte 2 */
            proto_tree_add_uint_format(tree, hf_sna_th_daf, tvb, 2, 1, daf,
                "Destination Address Field: 0x%02x", daf);
      }

      /* Set DST addr */
      ptr = tvb_get_ptr(tvb, 2, SNA_FID2_ADDR_LEN);
      SET_ADDRESS(&pinfo->net_dst, AT_SNA, SNA_FID2_ADDR_LEN, ptr);
      SET_ADDRESS(&pinfo->dst, AT_SNA, SNA_FID2_ADDR_LEN, ptr);

      if (tree) {
            /* Byte 3 */
            proto_tree_add_uint_format(tree, hf_sna_th_oaf, tvb, 3, 1, oaf,
                "Origin Address Field: 0x%02x", oaf);
      }

      /* Set SRC addr */
      ptr = tvb_get_ptr(tvb, 3, SNA_FID2_ADDR_LEN);
      SET_ADDRESS(&pinfo->net_src, AT_SNA, SNA_FID2_ADDR_LEN, ptr);
      SET_ADDRESS(&pinfo->src, AT_SNA, SNA_FID2_ADDR_LEN, ptr);

      id = tvb_get_ntohs(tvb, 4);
      if (tree)
            proto_tree_add_uint(tree, hf_sna_th_snf, tvb, 4, 2, id);

      if (mpf != MPF_WHOLE_BIU && !sna_defragment) {
            if (mpf == MPF_FIRST_SEGMENT) {
                  *continue_dissecting = rh_only;
            } else {
                  *continue_dissecting = stop_here;
            }

      }
      else if (sna_defragment) {
            *rh_tvb_ptr = defragment_by_sequence(pinfo, tvb,
                bytes_in_header, mpf, id);
      }

      return bytes_in_header;
}

/* FID Type 3 */
static int
dissect_fid3(tvbuff_t *tvb, proto_tree *tree)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      guint8            th_0;

      const int bytes_in_header = 2;

      /* If we're not filling a proto_tree, return now */
      if (!tree)
            return bytes_in_header;

      th_0 = tvb_get_guint8(tvb, 0);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_uint(tree, hf_sna_th_0, tvb, 0, 1, th_0);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      proto_tree_add_uint(bf_tree, hf_sna_th_fid, tvb, 0, 1, th_0);
      proto_tree_add_uint(bf_tree, hf_sna_th_mpf, tvb, 0, 1, th_0);
      proto_tree_add_uint(bf_tree, hf_sna_th_efi, tvb, 0, 1, th_0);

      proto_tree_add_item(tree, hf_sna_th_lsid, tvb, 1, 1, FALSE);

      return bytes_in_header;
}

static int
dissect_fid4(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      int         offset = 0;
      guint8            th_byte, mft;
      guint16           th_word;
      guint16           def, oef;
      guint32           dsaf, osaf;
      static struct sna_fid_type_4_addr src, dst;

      const int bytes_in_header = 26;

      /* If we're not filling a proto_tree, return now */
      if (!tree)
            return bytes_in_header;

      th_byte = tvb_get_guint8(tvb, offset);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_uint(tree, hf_sna_th_0, tvb, offset,
          1, th_byte);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      /* Byte 0 */
      proto_tree_add_uint(bf_tree, hf_sna_th_fid, tvb,
          offset, 1, th_byte);
      proto_tree_add_uint(bf_tree, hf_sna_th_tg_sweep, tvb,
          offset, 1, th_byte);
      proto_tree_add_uint(bf_tree, hf_sna_th_er_vr_supp_ind, tvb,
          offset, 1, th_byte);
      proto_tree_add_uint(bf_tree, hf_sna_th_vr_pac_cnt_ind, tvb,
          offset, 1, th_byte);
      proto_tree_add_uint(bf_tree, hf_sna_th_ntwk_prty, tvb,
          offset, 1, th_byte);

      offset += 1;
      th_byte = tvb_get_guint8(tvb, offset);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_text(tree, tvb, offset, 1,
          "Transmision Header Byte 1");
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      /* Byte 1 */
      proto_tree_add_uint(bf_tree, hf_sna_th_tgsf, tvb, offset, 1,
          th_byte);
      proto_tree_add_boolean(bf_tree, hf_sna_th_mft, tvb, offset, 1,
          th_byte);
      proto_tree_add_uint(bf_tree, hf_sna_th_piubf, tvb, offset, 1,
          th_byte);

      mft = th_byte & 0x04;
      offset += 1;
      th_byte = tvb_get_guint8(tvb, offset);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_text(tree, tvb, offset, 1,
          "Transmision Header Byte 2");
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      /* Byte 2 */
      if (mft) {
            proto_tree_add_uint(bf_tree, hf_sna_th_nlpoi, tvb,
                offset, 1, th_byte);
            proto_tree_add_uint(bf_tree, hf_sna_th_nlp_cp, tvb,
                offset, 1, th_byte);
      } else {
            proto_tree_add_uint(bf_tree, hf_sna_th_iern, tvb,
                offset, 1, th_byte);
      }
      proto_tree_add_uint(bf_tree, hf_sna_th_ern, tvb, offset, 1,
          th_byte);

      offset += 1;
      th_byte = tvb_get_guint8(tvb, offset);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_text(tree, tvb, offset, 1,
          "Transmision Header Byte 3");
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      /* Byte 3 */
      proto_tree_add_uint(bf_tree, hf_sna_th_vrn, tvb, offset, 1,
          th_byte);
      proto_tree_add_uint(bf_tree, hf_sna_th_tpf, tvb, offset, 1,
          th_byte);

      offset += 1;
      th_word = tvb_get_ntohs(tvb, offset);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_text(tree, tvb, offset, 2,
          "Transmision Header Bytes 4-5");
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      /* Bytes 4-5 */
      proto_tree_add_uint(bf_tree, hf_sna_th_vr_cwi, tvb,
          offset, 2, th_word);
      proto_tree_add_boolean(bf_tree, hf_sna_th_tg_nonfifo_ind, tvb,
          offset, 2, th_word);
      proto_tree_add_uint(bf_tree, hf_sna_th_vr_sqti, tvb,
          offset, 2, th_word);

      /* I'm not sure about byte-order on this one... */
      proto_tree_add_uint(bf_tree, hf_sna_th_tg_snf, tvb,
          offset, 2, th_word);

      offset += 2;
      th_word = tvb_get_ntohs(tvb, offset);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_text(tree, tvb, offset, 2,
          "Transmision Header Bytes 6-7");
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      /* Bytes 6-7 */
      proto_tree_add_boolean(bf_tree, hf_sna_th_vrprq, tvb, offset,
          2, th_word);
      proto_tree_add_boolean(bf_tree, hf_sna_th_vrprs, tvb, offset,
          2, th_word);
      proto_tree_add_uint(bf_tree, hf_sna_th_vr_cwri, tvb, offset,
          2, th_word);
      proto_tree_add_boolean(bf_tree, hf_sna_th_vr_rwi, tvb, offset,
          2, th_word);

      /* I'm not sure about byte-order on this one... */
      proto_tree_add_uint(bf_tree, hf_sna_th_vr_snf_send, tvb,
          offset, 2, th_word);

      offset += 2;

      dsaf = tvb_get_ntohl(tvb, 8);
      /* Bytes 8-11 */
      proto_tree_add_uint(tree, hf_sna_th_dsaf, tvb, offset, 4, dsaf);

      offset += 4;

      osaf = tvb_get_ntohl(tvb, 12);
      /* Bytes 12-15 */
      proto_tree_add_uint(tree, hf_sna_th_osaf, tvb, offset, 4, osaf);

      offset += 4;
      th_byte = tvb_get_guint8(tvb, offset);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_text(tree, tvb, offset, 2,
          "Transmision Header Byte 16");
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      /* Byte 16 */
      proto_tree_add_boolean(tree, hf_sna_th_snai, tvb, offset, 1, th_byte);

      /* We luck out here because in their infinite wisdom the SNA
       * architects placed the MPF and EFI fields in the same bitfield
       * locations, even though for FID4 they're not in byte 0.
       * Thank you IBM! */
      proto_tree_add_uint(tree, hf_sna_th_mpf, tvb, offset, 1, th_byte);
      proto_tree_add_uint(tree, hf_sna_th_efi, tvb, offset, 1, th_byte);

      offset += 2;
      /* 1 for byte 16, 1 for byte 17 which is reserved */

      def = tvb_get_ntohs(tvb, 18);
      /* Bytes 18-25 */
      proto_tree_add_uint(tree, hf_sna_th_def, tvb, offset, 2, def);

      /* Addresses in FID 4 are discontiguous, sigh */
      dst.saf = dsaf;
      dst.ef = def;
      SET_ADDRESS(&pinfo->net_dst, AT_SNA, SNA_FID_TYPE_4_ADDR_LEN,
          (guint8* )&dst);
      SET_ADDRESS(&pinfo->dst, AT_SNA, SNA_FID_TYPE_4_ADDR_LEN,
          (guint8 *)&dst);

      oef = tvb_get_ntohs(tvb, 20);
      proto_tree_add_uint(tree, hf_sna_th_oef, tvb, offset+2, 2, oef);

      /* Addresses in FID 4 are discontiguous, sigh */
      src.saf = osaf;
      src.ef = oef;
      SET_ADDRESS(&pinfo->net_src, AT_SNA, SNA_FID_TYPE_4_ADDR_LEN,
          (guint8 *)&src);
      SET_ADDRESS(&pinfo->src, AT_SNA, SNA_FID_TYPE_4_ADDR_LEN,
          (guint8 *)&src);

      proto_tree_add_item(tree, hf_sna_th_snf, tvb, offset+4, 2, FALSE);
      proto_tree_add_item(tree, hf_sna_th_dcf, tvb, offset+6, 2, FALSE);

      return bytes_in_header;
}

/* FID Type 5 */
static int
dissect_fid5(tvbuff_t *tvb, proto_tree *tree)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      guint8            th_0;

      const int bytes_in_header = 12;

      /* If we're not filling a proto_tree, return now */
      if (!tree)
            return bytes_in_header;

      th_0 = tvb_get_guint8(tvb, 0);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_uint(tree, hf_sna_th_0, tvb, 0, 1, th_0);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      proto_tree_add_uint(bf_tree, hf_sna_th_fid, tvb, 0, 1, th_0);
      proto_tree_add_uint(bf_tree, hf_sna_th_mpf, tvb, 0, 1, th_0);
      proto_tree_add_uint(bf_tree, hf_sna_th_efi, tvb, 0, 1, th_0);

      proto_tree_add_text(tree, tvb, 1, 1, "Reserved");
      proto_tree_add_item(tree, hf_sna_th_snf, tvb, 2, 2, FALSE);

      proto_tree_add_item(tree, hf_sna_th_sa, tvb, 4, 8, FALSE);

      return bytes_in_header;

}

/* FID Type f */
static int
dissect_fidf(tvbuff_t *tvb, proto_tree *tree)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      guint8            th_0;

      const int bytes_in_header = 26;

      /* If we're not filling a proto_tree, return now */
      if (!tree)
            return bytes_in_header;

      th_0 = tvb_get_guint8(tvb, 0);

      /* Create the bitfield tree */
      bf_item = proto_tree_add_uint(tree, hf_sna_th_0, tvb, 0, 1, th_0);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_th_fid);

      proto_tree_add_uint(bf_tree, hf_sna_th_fid, tvb, 0, 1, th_0);
      proto_tree_add_text(tree, tvb, 1, 1, "Reserved");

      proto_tree_add_item(tree, hf_sna_th_cmd_fmt, tvb,  2, 1, FALSE);
      proto_tree_add_item(tree, hf_sna_th_cmd_type, tvb, 3, 1, FALSE);
      proto_tree_add_item(tree, hf_sna_th_cmd_sn, tvb,   4, 2, FALSE);

      /* Yup, bytes 6-23 are reserved! */
      proto_tree_add_text(tree, tvb, 6, 18, "Reserved");

      proto_tree_add_item(tree, hf_sna_th_dcf, tvb, 24, 2, FALSE);

      return bytes_in_header;
}

static void
dissect_fid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
    proto_tree *parent_tree)
{

      proto_tree  *th_tree = NULL, *rh_tree = NULL;
      proto_item  *th_ti = NULL, *rh_ti = NULL;
      guint8            th_fid;
      int         th_header_len = 0;
      int         offset, rh_offset;
      tvbuff_t    *rh_tvb = NULL;
      next_dissection_t continue_dissecting = everything;

      /* Transmission Header Format Identifier */
      th_fid = hi_nibble(tvb_get_guint8(tvb, 0));

      /* Summary information */
      if (check_col(pinfo->cinfo, COL_INFO))
            col_add_str(pinfo->cinfo, COL_INFO,
                val_to_str(th_fid, sna_th_fid_vals, "Unknown FID: %01x"));

      if (tree) {
            /* --- TH --- */
            /* Don't bother setting length. We'll set it later after we
             * find the length of TH */
            th_ti = proto_tree_add_item(tree, hf_sna_th, tvb,  0, -1,
                FALSE);
            th_tree = proto_item_add_subtree(th_ti, ett_sna_th);
      }

      /* Get size of TH */
      switch(th_fid) {
            case 0x0:
            case 0x1:
                  th_header_len = dissect_fid0_1(tvb, pinfo, th_tree);
                  break;
            case 0x2:
                  th_header_len = dissect_fid2(tvb, pinfo, th_tree,
                      &rh_tvb, &continue_dissecting);
                  break;
            case 0x3:
                  th_header_len = dissect_fid3(tvb, th_tree);
                  break;
            case 0x4:
                  th_header_len = dissect_fid4(tvb, pinfo, th_tree);
                  break;
            case 0x5:
                  th_header_len = dissect_fid5(tvb, th_tree);
                  break;
            case 0xf:
                  th_header_len = dissect_fidf(tvb, th_tree);
                  break;
            default:
                  call_dissector(data_handle,
                      tvb_new_subset(tvb, 1, -1, -1), pinfo, parent_tree);
                  return;
      }

      offset = th_header_len;

      /* Short-circuit ? */
      if (continue_dissecting == stop_here) {
            if (tree) {
                  proto_tree_add_text(tree, tvb, offset, -1,
                      "BIU segment data");
            }
            return;
      }

      /* If the FID dissector function didn't create an rh_tvb, then we just
       * use the rest of our tvbuff as the rh_tvb. */
      if (!rh_tvb)
            rh_tvb = tvb_new_subset(tvb, offset, -1, -1);
      rh_offset = 0;

      /* Process the rest of the SNA packet, starting with RH */
      if (tree) {
            proto_item_set_len(th_ti, th_header_len);

            /* --- RH --- */
            rh_ti = proto_tree_add_item(tree, hf_sna_rh, rh_tvb, rh_offset,
                RH_LEN, FALSE);
            rh_tree = proto_item_add_subtree(rh_ti, ett_sna_rh);
            dissect_rh(rh_tvb, rh_offset, rh_tree);
      }

      rh_offset += RH_LEN;

      if (tvb_offset_exists(rh_tvb, rh_offset)) {
            /* Short-circuit ? */
            if (continue_dissecting == rh_only) {
                  if (tree)
                        proto_tree_add_text(tree, rh_tvb, rh_offset, -1,
                            "BIU segment data");
                  return;
            }

            call_dissector(data_handle, 
                tvb_new_subset(rh_tvb, rh_offset, -1, -1), 
                pinfo, parent_tree);
      }
}

/* --------------------------------------------------------------------
 * Chapter 5 Request/Response Headers (RHs)
 * --------------------------------------------------------------------
 */

static void
dissect_rh(tvbuff_t *tvb, int offset, proto_tree *tree)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      gboolean    is_response;
      guint8            rh_0, rh_1, rh_2;

      if (!tree)
            return;

      /* Create the bitfield tree for byte 0*/
      rh_0 = tvb_get_guint8(tvb, offset);
      is_response = (rh_0 & 0x80);

      bf_item = proto_tree_add_uint(tree, hf_sna_rh_0, tvb, offset, 1, rh_0);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_rh_0);

      proto_tree_add_uint(bf_tree, hf_sna_rh_rri, tvb, offset, 1, rh_0);
      proto_tree_add_uint(bf_tree, hf_sna_rh_ru_category, tvb, offset, 1,
          rh_0);
      proto_tree_add_boolean(bf_tree, hf_sna_rh_fi, tvb, offset, 1, rh_0);
      proto_tree_add_boolean(bf_tree, hf_sna_rh_sdi, tvb, offset, 1, rh_0);
      proto_tree_add_boolean(bf_tree, hf_sna_rh_bci, tvb, offset, 1, rh_0);
      proto_tree_add_boolean(bf_tree, hf_sna_rh_eci, tvb, offset, 1, rh_0);

      offset += 1;
      rh_1 = tvb_get_guint8(tvb, offset);

      /* Create the bitfield tree for byte 1*/
      bf_item = proto_tree_add_uint(tree, hf_sna_rh_1, tvb, offset, 1, rh_1);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_rh_1);

      proto_tree_add_boolean(bf_tree, hf_sna_rh_dr1, tvb,  offset, 1, rh_1);

      if (!is_response)
            proto_tree_add_boolean(bf_tree, hf_sna_rh_lcci, tvb, offset, 1,
                rh_1);

      proto_tree_add_boolean(bf_tree, hf_sna_rh_dr2, tvb,  offset, 1, rh_1);

      if (is_response) {
            proto_tree_add_boolean(bf_tree, hf_sna_rh_rti, tvb,  offset, 1,
                rh_1);
      } else {
            proto_tree_add_boolean(bf_tree, hf_sna_rh_eri, tvb,  offset, 1,
                rh_1);
            proto_tree_add_boolean(bf_tree, hf_sna_rh_rlwi, tvb, offset, 1,
                rh_1);
      }

      proto_tree_add_boolean(bf_tree, hf_sna_rh_qri, tvb, offset, 1, rh_1);
      proto_tree_add_boolean(bf_tree, hf_sna_rh_pi, tvb,  offset, 1, rh_1);

      offset += 1;
      rh_2 = tvb_get_guint8(tvb, offset);

      /* Create the bitfield tree for byte 2*/
      bf_item = proto_tree_add_uint(tree, hf_sna_rh_2, tvb, offset, 1, rh_2);

      if (!is_response) {
            bf_tree = proto_item_add_subtree(bf_item, ett_sna_rh_2);

            proto_tree_add_boolean(bf_tree, hf_sna_rh_bbi, tvb,  offset, 1,
                rh_2);
            proto_tree_add_boolean(bf_tree, hf_sna_rh_ebi, tvb,  offset, 1,
                rh_2);
            proto_tree_add_boolean(bf_tree, hf_sna_rh_cdi, tvb,  offset, 1,
                rh_2);
            proto_tree_add_uint(bf_tree, hf_sna_rh_csi, tvb,  offset, 1,
                rh_2);
            proto_tree_add_boolean(bf_tree, hf_sna_rh_edi, tvb,  offset, 1,
                rh_2);
            proto_tree_add_boolean(bf_tree, hf_sna_rh_pdi, tvb,  offset, 1,
                rh_2);
            proto_tree_add_boolean(bf_tree, hf_sna_rh_cebi, tvb, offset, 1,
                rh_2);
      }

      /* XXX - check for sdi. If TRUE, the next 4 bytes will be sense data */
}

/* --------------------------------------------------------------------
 * Chapter 6 Request/Response Units (RUs)
 * --------------------------------------------------------------------
 */

/* --------------------------------------------------------------------
 * Chapter 9 Common Fields
 * --------------------------------------------------------------------
 */

static void
dissect_control_05hpr(tvbuff_t *tvb, proto_tree *tree, int hpr,
    enum parse parse)
{
      proto_tree  *bf_tree;
      proto_item  *bf_item;
      guint8            type;
      guint16           offset, len, pad;

      if (!tree)
            return;

      type = tvb_get_guint8(tvb, 2);

      bf_item = proto_tree_add_uint(tree, hf_sna_control_05_type, tvb,
          2, 1, type);
      bf_tree = proto_item_add_subtree(bf_item, ett_sna_control_05hpr_type);

      proto_tree_add_boolean(bf_tree, hf_sna_control_05_ptp, tvb, 2, 1, type);
      proto_tree_add_text(tree, tvb, 3, 1, "Reserved");

      offset = 4;

      while (tvb_offset_exists(tvb, offset)) {
            if (parse == LT) {
                  len = tvb_get_guint8(tvb, offset+0);
            } else {
                  len = tvb_get_guint8(tvb, offset+1);
            }
            if (len) {
                  dissect_control(tvb, offset, len, tree, hpr, parse);
                  pad = (len+3) & 0xfffc;
                  if (pad > len)
                        proto_tree_add_text(tree, tvb, offset+len,
                            pad-len, "Padding");
                  offset += pad;
            } else {
                  return;
            }
      }
}

static void
dissect_control_05(tvbuff_t *tvb, proto_tree *tree)
{
      if(!tree)
            return;

      proto_tree_add_item(tree, hf_sna_control_05_delay, tvb, 2, 2, FALSE);
}

static void
dissect_control_0e(tvbuff_t *tvb, proto_tree *tree)
{
      gint  len;
      guint8      *buf;

      if (!tree)
            return;

      proto_tree_add_item(tree, hf_sna_control_0e_type, tvb, 2, 1, FALSE);

      len = tvb_reported_length_remaining(tvb, 3);
      if (len <= 0)
            return;

      buf = tvb_get_string(tvb, 3, len);
      EBCDIC_to_ASCII(buf, len);
      proto_tree_add_string(tree, hf_sna_control_0e_value, tvb, 3, len, buf);
      g_free(buf);
}

static void
dissect_control(tvbuff_t *parent_tvb, int offset, int control_len,
    proto_tree *tree, int hpr, enum parse parse)
{
      tvbuff_t    *tvb;
      gint        length, reported_length;
      proto_tree  *sub_tree;
      proto_item  *sub_item;
      int         len, key;
      gint        ett;

      length = tvb_length_remaining(parent_tvb, offset);
      reported_length = tvb_reported_length_remaining(parent_tvb, offset);
      if (control_len < length)
            length = control_len;
      if (control_len < reported_length)
            reported_length = control_len;
      tvb = tvb_new_subset(parent_tvb, offset, length, reported_length);

      sub_tree = NULL;

      if (parse == LT) {
            len = tvb_get_guint8(tvb, 0);
            key = tvb_get_guint8(tvb, 1);
      } else {
            key = tvb_get_guint8(tvb, 0);
            len = tvb_get_guint8(tvb, 1);
      }
      ett = ett_sna_control_un;

      if (tree) {
            if (key == 5) {
                   if (hpr) ett = ett_sna_control_05hpr;
                   else ett = ett_sna_control_05;
            }
            if (key == 0x0e) ett = ett_sna_control_0e;

            if (((key == 0) || (key == 3) || (key == 5)) && hpr)
                  sub_item = proto_tree_add_text(tree, tvb, 0, -1,
                      val_to_str(key, sna_control_hpr_vals,
                      "Unknown Control Vector"));
            else
                  sub_item = proto_tree_add_text(tree, tvb, 0, -1,
                      val_to_str(key, sna_control_vals,
                      "Unknown Control Vector"));
            sub_tree = proto_item_add_subtree(sub_item, ett);
            if (parse == LT) {
                  proto_tree_add_uint(sub_tree, hf_sna_control_len,
                      tvb, 0, 1, len);
                  if (((key == 0) || (key == 3) || (key == 5)) && hpr)
                        proto_tree_add_uint(sub_tree,
                            hf_sna_control_hprkey, tvb, 1, 1, key);
                  else
                        proto_tree_add_uint(sub_tree,
                            hf_sna_control_key, tvb, 1, 1, key);
            } else {
                  if (((key == 0) || (key == 3) || (key == 5)) && hpr)
                        proto_tree_add_uint(sub_tree,
                            hf_sna_control_hprkey, tvb, 0, 1, key);
                  else
                        proto_tree_add_uint(sub_tree,
                            hf_sna_control_key, tvb, 0, 1, key);
                  proto_tree_add_uint(sub_tree, hf_sna_control_len,
                      tvb, 1, 1, len);
            }
      }
      switch(key) {
            case 0x05:
                  if (hpr)
                        dissect_control_05hpr(tvb, sub_tree, hpr,
                            parse);
                  else
                        dissect_control_05(tvb, sub_tree);
                  break;
            case 0x0e:
                  dissect_control_0e(tvb, sub_tree);
                  break;
      }
}

/* --------------------------------------------------------------------
 * Chapter 11 Function Management (FM) Headers
 * --------------------------------------------------------------------
 */

/* --------------------------------------------------------------------
 * Chapter 12 Presentation Services (PS) Headers
 * --------------------------------------------------------------------
 */

/* --------------------------------------------------------------------
 * Chapter 13 GDS Variables
 * --------------------------------------------------------------------
 */

static void
dissect_gds(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, 
    proto_tree *parent_tree)
{
      guint16           length;
      guint16           type;
      int         cont;
      int         offset;
      proto_tree  *gds_tree;
      proto_item  *gds_item;

      offset = 0;
      cont   = 1;
      type   = tvb_get_ntohs(tvb, offset+2);

      while (cont) {
            length = tvb_get_ntohs(tvb, offset) & 0x7fff;
            cont   = (tvb_get_ntohs(tvb, offset) & 0x8000) ? 1 : 0;
            type   = tvb_get_ntohs(tvb, offset+2);

            if (length < 2 ) /* escape sequence ? */
                  return;
            if (tree) {
                  gds_item = proto_tree_add_item(tree, hf_sna_gds, tvb,
                      offset, length, FALSE);
                  gds_tree = proto_item_add_subtree(gds_item,
                      ett_sna_gds);

                  proto_tree_add_uint(gds_tree, hf_sna_gds_len, tvb,
                      offset, 2, length);
                  proto_tree_add_boolean(gds_tree, hf_sna_gds_cont, tvb,
                      offset, 2, cont);
                  proto_tree_add_uint(gds_tree, hf_sna_gds_type, tvb,
                      offset+2, 2, type);
            }
            offset += length;
      }
      if (tvb_offset_exists(tvb, offset))
            call_dissector(data_handle,
                tvb_new_subset(tvb, offset, -1, -1), pinfo, parent_tree);
}

/* --------------------------------------------------------------------
 * General stuff
 * --------------------------------------------------------------------
 */

static void
dissect_sna(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      guint8            fid;
      proto_tree  *sna_tree = NULL;
      proto_item  *sna_ti = NULL;

      if (check_col(pinfo->cinfo, COL_PROTOCOL))
            col_set_str(pinfo->cinfo, COL_PROTOCOL, "SNA");
      if (check_col(pinfo->cinfo, COL_INFO))
            col_clear(pinfo->cinfo, COL_INFO);

      /* SNA data should be printed in EBCDIC, not ASCII */
      pinfo->fd->flags.encoding = CHAR_EBCDIC;

      if (tree) {

            /* Don't bother setting length. We'll set it later after we find
             * the lengths of TH/RH/RU */
            sna_ti = proto_tree_add_item(tree, proto_sna, tvb, 0, -1,
                FALSE);
            sna_tree = proto_item_add_subtree(sna_ti, ett_sna);
      }

      /* Transmission Header Format Identifier */
      fid = hi_nibble(tvb_get_guint8(tvb, 0));
      switch(fid) {
            case 0xa:   /* HPR Network Layer Packet */
            case 0xb:
            case 0xc:
            case 0xd:
                  dissect_nlp(tvb, pinfo, sna_tree, tree);
                  break;
            default:
                  dissect_fid(tvb, pinfo, sna_tree, tree);
      }
}

static void
dissect_sna_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
      proto_tree  *sna_tree = NULL;
      proto_item  *sna_ti = NULL;

      if (check_col(pinfo->cinfo, COL_PROTOCOL))
            col_set_str(pinfo->cinfo, COL_PROTOCOL, "SNA");
      if (check_col(pinfo->cinfo, COL_INFO))
            col_clear(pinfo->cinfo, COL_INFO);

      /* SNA data should be printed in EBCDIC, not ASCII */
      pinfo->fd->flags.encoding = CHAR_EBCDIC;

      if (tree) {

            /* Don't bother setting length. We'll set it later after we find
             * the lengths of XID */
            sna_ti = proto_tree_add_item(tree, proto_sna_xid, tvb, 0, -1,
                FALSE);
            sna_tree = proto_item_add_subtree(sna_ti, ett_sna);
      }
      dissect_xid(tvb, pinfo, sna_tree, tree);
}

static void
sna_init(void)
{
      fragment_table_init(&sna_fragment_table);
      reassembled_table_init(&sna_reassembled_table);
}


void
proto_register_sna(void)
{
        static hf_register_info hf[] = {
                { &hf_sna_th,
                { "Transmission Header", "sna.th", FT_NONE, BASE_NONE,
                 NULL, 0x0, "", HFILL }},

                { &hf_sna_th_0,
                { "Transmission Header Byte 0", "sna.th.0", FT_UINT8, BASE_HEX,
                NULL, 0x0,
                "TH Byte 0", HFILL }},

                { &hf_sna_th_fid,
                { "Format Identifer", "sna.th.fid", FT_UINT8, BASE_HEX,
                VALS(sna_th_fid_vals), 0xf0, "", HFILL }},

                { &hf_sna_th_mpf,
                { "Mapping Field", "sna.th.mpf", FT_UINT8,
                BASE_DEC, VALS(sna_th_mpf_vals), 0x0c, "", HFILL }},

            { &hf_sna_th_odai,
            { "ODAI Assignment Indicator", "sna.th.odai", FT_UINT8,
                BASE_DEC, NULL, 0x02, "", HFILL }},

                { &hf_sna_th_efi,
                { "Expedited Flow Indicator", "sna.th.efi", FT_UINT8,
                BASE_DEC, VALS(sna_th_efi_vals), 0x01, "", HFILL }},

                { &hf_sna_th_daf,
                { "Destination Address Field", "sna.th.daf", FT_UINT16,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_th_oaf,
                { "Origin Address Field", "sna.th.oaf", FT_UINT16, BASE_HEX,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_th_snf,
                { "Sequence Number Field", "sna.th.snf", FT_UINT16, BASE_DEC,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_th_dcf,
                { "Data Count Field", "sna.th.dcf", FT_UINT16, BASE_DEC,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_th_lsid,
                { "Local Session Identification", "sna.th.lsid", FT_UINT8,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_th_tg_sweep,
                { "Transmission Group Sweep", "sna.th.tg_sweep", FT_UINT8,
                BASE_DEC, VALS(sna_th_tg_sweep_vals), 0x08, "", HFILL }},

                { &hf_sna_th_er_vr_supp_ind,
                { "ER and VR Support Indicator", "sna.th.er_vr_supp_ind",
                FT_UINT8, BASE_DEC, VALS(sna_th_er_vr_supp_ind_vals),
                0x04, "", HFILL }},

                { &hf_sna_th_vr_pac_cnt_ind,
                { "Virtual Route Pacing Count Indicator",
                "sna.th.vr_pac_cnt_ind", FT_UINT8, BASE_DEC,
                VALS(sna_th_vr_pac_cnt_ind_vals), 0x02, "", HFILL }},

                { &hf_sna_th_ntwk_prty,
                { "Network Priority", "sna.th.ntwk_prty", FT_UINT8, BASE_DEC,
                VALS(sna_th_ntwk_prty_vals), 0x01, "", HFILL }},

                { &hf_sna_th_tgsf,
                { "Transmission Group Segmenting Field", "sna.th.tgsf",
                FT_UINT8, BASE_HEX, VALS(sna_th_tgsf_vals), 0xc0,
                "", HFILL }},

                { &hf_sna_th_mft,
                { "MPR FID4 Type", "sna.th.mft", FT_BOOLEAN, BASE_NONE,
                NULL, 0x04, "", HFILL }},

                { &hf_sna_th_piubf,
                { "PIU Blocking Field", "sna.th.piubf", FT_UINT8, BASE_HEX,
                VALS(sna_th_piubf_vals), 0x03, "", HFILL }},

                { &hf_sna_th_iern,
                { "Initial Explicit Route Number", "sna.th.iern", FT_UINT8,
                BASE_DEC, NULL, 0xf0, "", HFILL }},

                { &hf_sna_th_nlpoi,
                { "NLP Offset Indicator", "sna.th.nlpoi", FT_UINT8, BASE_DEC,
                VALS(sna_th_nlpoi_vals), 0x80, "", HFILL }},

                { &hf_sna_th_nlp_cp,
                { "NLP Count or Padding", "sna.th.nlp_cp", FT_UINT8, BASE_DEC,
                NULL, 0x70, "", HFILL }},

                { &hf_sna_th_ern,
                { "Explicit Route Number", "sna.th.ern", FT_UINT8, BASE_DEC,
                NULL, 0x0f, "", HFILL }},

                { &hf_sna_th_vrn,
                { "Virtual Route Number", "sna.th.vrn", FT_UINT8, BASE_DEC,
                NULL, 0xf0, "", HFILL }},

                { &hf_sna_th_tpf,
                { "Transmission Priority Field", "sna.th.tpf", FT_UINT8,
                BASE_HEX, VALS(sna_th_tpf_vals), 0x03, "", HFILL }},

                { &hf_sna_th_vr_cwi,
                { "Virtual Route Change Window Indicator", "sna.th.vr_cwi",
                FT_UINT16, BASE_DEC, VALS(sna_th_vr_cwi_vals), 0x8000,
                "Change Window Indicator", HFILL }},

                { &hf_sna_th_tg_nonfifo_ind,
                { "Transmission Group Non-FIFO Indicator",
                "sna.th.tg_nonfifo_ind", FT_BOOLEAN, 16,
                TFS(&sna_th_tg_nonfifo_ind_truth), 0x4000, "", HFILL }},

                { &hf_sna_th_vr_sqti,
                { "Virtual Route Sequence and Type Indicator", "sna.th.vr_sqti",
                FT_UINT16, BASE_HEX, VALS(sna_th_vr_sqti_vals), 0x3000,
                "Route Sequence and Type", HFILL }},

                { &hf_sna_th_tg_snf,
                { "Transmission Group Sequence Number Field", "sna.th.tg_snf",
                FT_UINT16, BASE_DEC, NULL, 0x0fff, "", HFILL }},

                { &hf_sna_th_vrprq,
                { "Virtual Route Pacing Request", "sna.th.vrprq", FT_BOOLEAN,
                16, TFS(&sna_th_vrprq_truth), 0x8000, "", HFILL }},

                { &hf_sna_th_vrprs,
                { "Virtual Route Pacing Response", "sna.th.vrprs", FT_BOOLEAN,
                16, TFS(&sna_th_vrprs_truth), 0x4000, "", HFILL }},

                { &hf_sna_th_vr_cwri,
                { "Virtual Route Change Window Reply Indicator",
                "sna.th.vr_cwri", FT_UINT16, BASE_DEC,
                VALS(sna_th_vr_cwri_vals), 0x2000, "", HFILL }},

                { &hf_sna_th_vr_rwi,
                { "Virtual Route Reset Window Indicator", "sna.th.vr_rwi",
                FT_BOOLEAN, 16, TFS(&sna_th_vr_rwi_truth), 0x1000,
                "", HFILL }},

                { &hf_sna_th_vr_snf_send,
                { "Virtual Route Send Sequence Number Field",
                "sna.th.vr_snf_send", FT_UINT16, BASE_DEC, NULL, 0x0fff,
                "Send Sequence Number Field", HFILL }},

                { &hf_sna_th_dsaf,
                { "Destination Subarea Address Field", "sna.th.dsaf",
                FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_th_osaf,
                { "Origin Subarea Address Field", "sna.th.osaf", FT_UINT32,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_th_snai,
                { "SNA Indicator", "sna.th.snai", FT_BOOLEAN, 8, NULL, 0x10,
                "Used to identify whether the PIU originated or is destined"
                " for an SNA or non-SNA device.", HFILL }},

                { &hf_sna_th_def,
                { "Destination Element Field", "sna.th.def", FT_UINT16,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_th_oef,
                { "Origin Element Field", "sna.th.oef", FT_UINT16, BASE_HEX,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_th_sa,
                { "Session Address", "sna.th.sa", FT_BYTES, BASE_HEX,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_th_cmd_fmt,
                { "Command Format", "sna.th.cmd_fmt", FT_UINT8, BASE_HEX,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_th_cmd_type,
                { "Command Type", "sna.th.cmd_type", FT_UINT8, BASE_HEX,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_th_cmd_sn,
                { "Command Sequence Number", "sna.th.cmd_sn", FT_UINT16,
                BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_nhdr,
                { "Network Layer Packet Header", "sna.nlp.nhdr", FT_NONE,
                BASE_NONE, NULL, 0x0, "NHDR", HFILL }},

                { &hf_sna_nlp_nhdr_0,
                { "Network Layer Packet Header Byte 0",     "sna.nlp.nhdr.0",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_nhdr_1,
                { "Network Layer Packet Header Byte 1", "sna.nlp.nhdr.1",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_sm,
                { "Switching Mode Field", "sna.nlp.nhdr.sm", FT_UINT8,
                BASE_HEX, VALS(sna_nlp_sm_vals), 0xe0, "", HFILL }},

                { &hf_sna_nlp_tpf,
                { "Transmission Priority Field", "sna.nlp.nhdr.tpf", FT_UINT8,
                BASE_HEX, VALS(sna_th_tpf_vals), 0x06, "", HFILL }},

                { &hf_sna_nlp_ft,
                { "Function Type", "sna.nlp.nhdr.ft", FT_UINT8, BASE_HEX,
                VALS(sna_nlp_ft_vals), 0xF0, "", HFILL }},

                { &hf_sna_nlp_tspi,
                { "Time Sensitive Packet Indicator", "sna.nlp.nhdr.tspi",
                FT_BOOLEAN, 8, TFS(&sna_nlp_tspi_truth), 0x08, "", HFILL }},

                { &hf_sna_nlp_slowdn1,
                { "Slowdown 1", "sna.nlp.nhdr.slowdn1", FT_BOOLEAN, 8,
                TFS(&sna_nlp_slowdn1_truth), 0x04, "", HFILL }},

                { &hf_sna_nlp_slowdn2,
                { "Slowdown 2", "sna.nlp.nhdr.slowdn2", FT_BOOLEAN, 8,
                TFS(&sna_nlp_slowdn2_truth), 0x02, "", HFILL }},

                { &hf_sna_nlp_fra,
                { "Function Routing Address Entry", "sna.nlp.nhdr.fra",
                FT_BYTES, BASE_NONE, NULL, 0, "", HFILL }},

                { &hf_sna_nlp_anr,
                { "Automatic Network Routing Entry", "sna.nlp.nhdr.anr",
                FT_BYTES, BASE_HEX, NULL, 0, "", HFILL }},

                { &hf_sna_nlp_frh,
                { "Transmission Priority Field", "sna.nlp.frh", FT_UINT8,
                BASE_HEX, VALS(sna_nlp_frh_vals), 0, "", HFILL }},

                { &hf_sna_nlp_thdr,
                { "RTP Transport Header", "sna.nlp.thdr", FT_NONE, BASE_NONE,
                NULL, 0x0, "THDR", HFILL }},

                { &hf_sna_nlp_tcid,
                { "Transport Connection Identifier", "sna.nlp.thdr.tcid",
                FT_BYTES, BASE_HEX, NULL, 0x0, "TCID", HFILL }},

                { &hf_sna_nlp_thdr_8,
                { "RTP Transport Packet Header Byte 8", "sna.nlp.thdr.8",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_setupi,
                { "Setup Indicator", "sna.nlp.thdr.setupi", FT_BOOLEAN, 8,
                TFS(&sna_nlp_setupi_truth), 0x40, "", HFILL }},

                { &hf_sna_nlp_somi,
                { "Start Of Message Indicator", "sna.nlp.thdr.somi",
                FT_BOOLEAN, 8, TFS(&sna_nlp_somi_truth), 0x20, "", HFILL }},

                { &hf_sna_nlp_eomi,
                { "End Of Message Indicator", "sna.nlp.thdr.eomi", FT_BOOLEAN,
                8, TFS(&sna_nlp_eomi_truth), 0x10, "", HFILL }},

                { &hf_sna_nlp_sri,
                { "Session Request Indicator", "sna.nlp.thdr.sri", FT_BOOLEAN,
                8, TFS(&sna_nlp_sri_truth), 0x08, "", HFILL }},

                { &hf_sna_nlp_rasapi,
                { "Reply ASAP Indicator", "sna.nlp.thdr.rasapi", FT_BOOLEAN,
                8, TFS(&sna_nlp_rasapi_truth), 0x04, "", HFILL }},

                { &hf_sna_nlp_retryi,
                { "Retry Indicator", "sna.nlp.thdr.retryi", FT_BOOLEAN,
                8, TFS(&sna_nlp_retryi_truth), 0x02, "", HFILL }},

                { &hf_sna_nlp_thdr_9,
                { "RTP Transport Packet Header Byte 9", "sna.nlp.thdr.9",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_lmi,
                { "Last Message Indicator", "sna.nlp.thdr.lmi", FT_BOOLEAN,
                8, TFS(&sna_nlp_lmi_truth), 0x80, "", HFILL }},

                { &hf_sna_nlp_cqfi,
                { "Connection Qualifyer Field Indicator", "sna.nlp.thdr.cqfi",
                FT_BOOLEAN, 8, TFS(&sna_nlp_cqfi_truth), 0x08, "", HFILL }},

                { &hf_sna_nlp_osi,
                { "Optional Segments Present Indicator", "sna.nlp.thdr.osi",
                FT_BOOLEAN, 8, TFS(&sna_nlp_osi_truth), 0x04, "", HFILL }},

                { &hf_sna_nlp_offset,
                { "Data Offset/4", "sna.nlp.thdr.offset", FT_UINT16, BASE_HEX,
                NULL, 0x0, "Data Offset in Words", HFILL }},

                { &hf_sna_nlp_dlf,
                { "Data Length Field", "sna.nlp.thdr.dlf", FT_UINT32, BASE_HEX,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_bsn,
                { "Byte Sequence Number", "sna.nlp.thdr.bsn", FT_UINT32,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_len,
                { "Optional Segment Length/4", "sna.nlp.thdr.optional.len",
                FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_type,
                { "Optional Segment Type", "sna.nlp.thdr.optional.type",
                FT_UINT8, BASE_HEX, VALS(sna_nlp_opti_vals), 0x0, "",
                HFILL }},

                { &hf_sna_nlp_opti_0d_version,
                { "Version", "sna.nlp.thdr.optional.0d.version",
                FT_UINT16, BASE_HEX, VALS(sna_nlp_opti_0d_version_vals),
                0, "", HFILL }},

                { &hf_sna_nlp_opti_0d_4,
                { "Connection Setup Byte 4", "sna.nlp.thdr.optional.0e.4",
                FT_UINT8, BASE_HEX, NULL, 0, "", HFILL }},

                { &hf_sna_nlp_opti_0d_target,
                { "Target Resource ID Present",
                "sna.nlp.thdr.optional.0d.target",
                FT_BOOLEAN, 8, NULL, 0x80, "", HFILL }},

                { &hf_sna_nlp_opti_0d_arb,
                { "ARB Flow Control", "sna.nlp.thdr.optional.0d.arb",
                FT_BOOLEAN, 8, NULL, 0x10, "", HFILL }},

                { &hf_sna_nlp_opti_0d_reliable,
                { "Reliable Connection", "sna.nlp.thdr.optional.0d.reliable",
                FT_BOOLEAN, 8, NULL, 0x08, "", HFILL }},

                { &hf_sna_nlp_opti_0d_dedicated,
                { "Dedicated RTP Connection",
                "sna.nlp.thdr.optional.0d.dedicated",
                FT_BOOLEAN, 8, NULL, 0x04, "", HFILL }},

                { &hf_sna_nlp_opti_0e_stat,
                { "Status", "sna.nlp.thdr.optional.0e.stat",
                FT_UINT8, BASE_HEX, NULL, 0, "", HFILL }},

                { &hf_sna_nlp_opti_0e_gap,
                { "Gap Detected", "sna.nlp.thdr.optional.0e.gap",
                FT_BOOLEAN, 8, NULL, 0x80, "", HFILL }},

                { &hf_sna_nlp_opti_0e_idle,
                { "RTP Idle Packet", "sna.nlp.thdr.optional.0e.idle",
                FT_BOOLEAN, 8, NULL, 0x40, "", HFILL }},

                { &hf_sna_nlp_opti_0e_nabsp,
                { "Number Of ABSP", "sna.nlp.thdr.optional.0e.nabsp",
                FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_0e_sync,
                { "Status Report Number", "sna.nlp.thdr.optional.0e.sync",
                FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_0e_echo,
                { "Status Acknowledge Number", "sna.nlp.thdr.optional.0e.echo",
                FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_0e_rseq,
                { "Received Sequence Number", "sna.nlp.thdr.optional.0e.rseq",
                FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_0e_abspbeg,
                { "ABSP Begin", "sna.nlp.thdr.optional.0e.abspbeg",
                FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_0e_abspend,
                { "ABSP End", "sna.nlp.thdr.optional.0e.abspend",
                FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_0f_bits,
                { "Client Bits", "sna.nlp.thdr.optional.0f.bits",
                FT_UINT8, BASE_HEX, VALS(sna_nlp_opti_0f_bits_vals),
                0x0, "", HFILL }},

                { &hf_sna_nlp_opti_10_tcid,
                { "Transport Connection Identifier",
                "sna.nlp.thdr.optional.10.tcid",
                FT_BYTES, BASE_HEX, NULL, 0x0, "TCID", HFILL }},

                { &hf_sna_nlp_opti_12_sense,
                { "Sense Data", "sna.nlp.thdr.optional.12.sense",
                FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_len,
                { "Length", "sna.nlp.thdr.optional.14.si.len",
                FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_key,
                { "Key", "sna.nlp.thdr.optional.14.si.key",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_2,
                { "Switching Information Byte 2",
                "sna.nlp.thdr.optional.14.si.2",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_refifo,
                { "Resequencing (REFIFO) Indicator",
                "sna.nlp.thdr.optional.14.si.refifo",
                FT_BOOLEAN, 8, NULL, 0x80, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_mobility,
                { "Mobility Indicator",
                "sna.nlp.thdr.optional.14.si.mobility",
                FT_BOOLEAN, 8, NULL, 0x40, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_dirsearch,
                { "Directory Search Required on Path Switch Indicator",
                "sna.nlp.thdr.optional.14.si.dirsearch",
                FT_BOOLEAN, 8, NULL, 0x20, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_limitres,
                { "Limited Resource Link Indicator",
                "sna.nlp.thdr.optional.14.si.limitres",
                FT_BOOLEAN, 8, NULL, 0x10, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_ncescope,
                { "NCE Scope Indicator",
                "sna.nlp.thdr.optional.14.si.ncescope",
                FT_BOOLEAN, 8, NULL, 0x08, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_mnpsrscv,
                { "MNPS RSCV Retention Indicator",
                "sna.nlp.thdr.optional.14.si.mnpsrscv",
                FT_BOOLEAN, 8, NULL, 0x04, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_maxpsize,
                { "Maximum Packet Size On Return Path",
                "sna.nlp.thdr.optional.14.si.maxpsize",
                FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_switch,
                { "Path Switch Time", "sna.nlp.thdr.optional.14.si.switch",
                FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_si_alive,
                { "RTP Alive Timer", "sna.nlp.thdr.optional.14.si.alive",
                FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_rr_len,
                { "Length", "sna.nlp.thdr.optional.14.rr.len",
                FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_rr_key,
                { "Key", "sna.nlp.thdr.optional.14.rr.key",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_rr_2,
                { "Return Route TG Descriptor Byte 2",
                "sna.nlp.thdr.optional.14.rr.2",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_14_rr_bfe,
                { "BF Entry Indicator",
                "sna.nlp.thdr.optional.14.rr.bfe",
                FT_BOOLEAN, 8, NULL, 0x80, "", HFILL }},

                { &hf_sna_nlp_opti_14_rr_num,
                { "Number Of TG Control Vectors",
                "sna.nlp.thdr.optional.14.rr.num",
                FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_22_2,
                { "Adaptive Rate Based Segment Byte 2",
                "sna.nlp.thdr.optional.22.2",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_22_type,
                { "Message Type",
                "sna.nlp.thdr.optional.22.type",
                FT_UINT8, BASE_HEX,
                VALS(sna_nlp_opti_22_type_vals), 0xc0, "", HFILL }},

                { &hf_sna_nlp_opti_22_raa,
                { "Rate Adjustment Action",
                "sna.nlp.thdr.optional.22.raa",
                FT_UINT8, BASE_HEX,
                VALS(sna_nlp_opti_22_raa_vals), 0x38, "", HFILL }},

                { &hf_sna_nlp_opti_22_parity,
                { "Parity Indicator",
                "sna.nlp.thdr.optional.22.parity",
                FT_BOOLEAN, 8, NULL, 0x04, "", HFILL }},

                { &hf_sna_nlp_opti_22_arb,
                { "ARB Mode",
                "sna.nlp.thdr.optional.22.arb",
                FT_UINT8, BASE_HEX,
                VALS(sna_nlp_opti_22_arb_vals), 0x03, "", HFILL }},

                { &hf_sna_nlp_opti_22_3,
                { "Adaptive Rate Based Segment Byte 3",
                "sna.nlp.thdr.optional.22.3",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_22_ratereq,
                { "Rate Request Correlator",
                "sna.nlp.thdr.optional.22.ratereq",
                FT_UINT8, BASE_DEC, NULL, 0xf0, "", HFILL }},

                { &hf_sna_nlp_opti_22_raterep,
                { "Rate Reply Correlator",
                "sna.nlp.thdr.optional.22.raterep",
                FT_UINT8, BASE_DEC, NULL, 0x0f, "", HFILL }},

                { &hf_sna_nlp_opti_22_field1,
                { "Field 1", "sna.nlp.thdr.optional.22.field1",
                FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_22_field2,
                { "Field 2", "sna.nlp.thdr.optional.22.field2",
                FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_22_field3,
                { "Field 3", "sna.nlp.thdr.optional.22.field3",
                FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_nlp_opti_22_field4,
                { "Field 4", "sna.nlp.thdr.optional.22.field4",
                FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_rh,
                { "Request/Response Header", "sna.rh", FT_NONE, BASE_NONE,
                NULL, 0x0, "", HFILL }},

                { &hf_sna_rh_0,
                { "Request/Response Header Byte 0", "sna.rh.0", FT_UINT8,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_rh_1,
                { "Request/Response Header Byte 1", "sna.rh.1", FT_UINT8,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_rh_2,
                { "Request/Response Header Byte 2", "sna.rh.2", FT_UINT8,
                BASE_HEX, NULL, 0x0, "", HFILL }},

                { &hf_sna_rh_rri,
                { "Request/Response Indicator", "sna.rh.rri", FT_UINT8,
                BASE_DEC, VALS(sna_rh_rri_vals), 0x80, "", HFILL }},

                { &hf_sna_rh_ru_category,
                { "Request/Response Unit Category", "sna.rh.ru_category",
                FT_UINT8, BASE_HEX, VALS(sna_rh_ru_category_vals), 0x60,
                "", HFILL }},

            { &hf_sna_rh_fi,
            { "Format Indicator", "sna.rh.fi", FT_BOOLEAN, 8,
                TFS(&sna_rh_fi_truth), 0x08, "", HFILL }},

            { &hf_sna_rh_sdi,
            { "Sense Data Included", "sna.rh.sdi", FT_BOOLEAN, 8,
                TFS(&sna_rh_sdi_truth), 0x04, "", HFILL }},

            { &hf_sna_rh_bci,
            { "Begin Chain Indicator", "sna.rh.bci", FT_BOOLEAN, 8,
                TFS(&sna_rh_bci_truth), 0x02, "", HFILL }},

            { &hf_sna_rh_eci,
            { "End Chain Indicator", "sna.rh.eci", FT_BOOLEAN, 8,
                TFS(&sna_rh_eci_truth), 0x01, "", HFILL }},

            { &hf_sna_rh_dr1,
            { "Definite Response 1 Indicator", "sna.rh.dr1", FT_BOOLEAN,
                8, NULL, 0x80, "", HFILL }},

            { &hf_sna_rh_lcci,
            { "Length-Checked Compression Indicator", "sna.rh.lcci",
                FT_BOOLEAN, 8, TFS(&sna_rh_lcci_truth), 0x40, "", HFILL }},

            { &hf_sna_rh_dr2,
            { "Definite Response 2 Indicator", "sna.rh.dr2", FT_BOOLEAN,
                8, NULL, 0x20, "", HFILL }},

            { &hf_sna_rh_eri,
            { "Exception Response Indicator", "sna.rh.eri", FT_BOOLEAN,
                8, NULL, 0x10, "", HFILL }},

            { &hf_sna_rh_rti,
            { "Response Type Indicator", "sna.rh.rti", FT_BOOLEAN,
                8, TFS(&sna_rh_rti_truth), 0x10, "", HFILL }},

            { &hf_sna_rh_rlwi,
            { "Request Larger Window Indicator", "sna.rh.rlwi", FT_BOOLEAN,
                8, NULL, 0x04, "", HFILL }},

            { &hf_sna_rh_qri,
            { "Queued Response Indicator", "sna.rh.qri", FT_BOOLEAN,
                8, TFS(&sna_rh_qri_truth), 0x02, "", HFILL }},

            { &hf_sna_rh_pi,
            { "Pacing Indicator", "sna.rh.pi", FT_BOOLEAN,
                8, NULL, 0x01, "", HFILL }},

            { &hf_sna_rh_bbi,
            { "Begin Bracket Indicator", "sna.rh.bbi", FT_BOOLEAN,
                8, NULL, 0x80, "", HFILL }},

            { &hf_sna_rh_ebi,
            { "End Bracket Indicator", "sna.rh.ebi", FT_BOOLEAN,
                8, NULL, 0x40, "", HFILL }},

            { &hf_sna_rh_cdi,
            { "Change Direction Indicator", "sna.rh.cdi", FT_BOOLEAN,
                8, NULL, 0x20, "", HFILL }},

            { &hf_sna_rh_csi,
            { "Code Selection Indicator", "sna.rh.csi", FT_UINT8, BASE_DEC,
                VALS(sna_rh_csi_vals), 0x08, "", HFILL }},

            { &hf_sna_rh_edi,
            { "Enciphered Data Indicator", "sna.rh.edi", FT_BOOLEAN, 8,
                NULL, 0x04, "", HFILL }},

            { &hf_sna_rh_pdi,
            { "Padded Data Indicator", "sna.rh.pdi", FT_BOOLEAN, 8, NULL,
                0x02, "", HFILL }},

            { &hf_sna_rh_cebi,
            { "Conditional End Bracket Indicator", "sna.rh.cebi",
                FT_BOOLEAN, 8, NULL, 0x01, "", HFILL }},

/*          { &hf_sna_ru,
            { "Request/Response Unit", "sna.ru", FT_NONE, BASE_NONE,
                NULL, 0x0, "", HFILL }},*/

            { &hf_sna_gds,
            { "GDS Variable", "sna.gds", FT_NONE, BASE_NONE, NULL, 0x0,
                "", HFILL }},

            { &hf_sna_gds_len,
            { "GDS Variable Length", "sna.gds.len", FT_UINT16, BASE_DEC,
                NULL, 0x7fff, "", HFILL }},

            { &hf_sna_gds_cont,
            { "Continuation Flag", "sna.gds.cont", FT_BOOLEAN, 16, NULL,
                0x8000, "", HFILL }},

            { &hf_sna_gds_type,
            { "Type of Variable", "sna.gds.type", FT_UINT16, BASE_HEX,
                VALS(sna_gds_var_vals), 0x0, "", HFILL }},

            { &hf_sna_xid,
            { "XID", "sna.xid", FT_NONE, BASE_NONE, NULL, 0x0,
                "XID Frame", HFILL }},

            { &hf_sna_xid_0,
            { "XID Byte 0", "sna.xid.0", FT_UINT8, BASE_HEX, NULL, 0x0,
                "", HFILL }},

            { &hf_sna_xid_format,
            { "XID Format", "sna.xid.format", FT_UINT8, BASE_DEC, NULL,
                0xf0, "", HFILL }},

            { &hf_sna_xid_type,
            { "XID Type", "sna.xid.type", FT_UINT8, BASE_DEC,
                VALS(sna_xid_type_vals), 0x0f, "", HFILL }},

            { &hf_sna_xid_len,
            { "XID Length", "sna.xid.len", FT_UINT8, BASE_DEC, NULL, 0x0,
                "", HFILL }},

            { &hf_sna_xid_id,
            { "Node Identification", "sna.xid.id", FT_UINT32, BASE_HEX,
                NULL, 0x0, "", HFILL }},

            { &hf_sna_xid_idblock,
            { "ID Block", "sna.xid.idblock", FT_UINT32, BASE_HEX, NULL, 
                0xfff00000, "", HFILL }},

            { &hf_sna_xid_idnum,
            { "ID Number", "sna.xid.idnum", FT_UINT32, BASE_HEX, NULL,
                0x0fffff, "", HFILL }},

            { &hf_sna_xid_3_8,
            { "Characteristics of XID sender", "sna.xid.type3.8", FT_UINT16,
                BASE_HEX, NULL, 0x0, "", HFILL }},

            { &hf_sna_xid_3_init_self,
            { "INIT-SELF support", "sna.xid.type3.initself",
                FT_BOOLEAN, 16, NULL, 0x8000, "", HFILL }},

            { &hf_sna_xid_3_stand_bind,
            { "Stand-Alone BIND Support", "sna.xid.type3.stand_bind",
                FT_BOOLEAN, 16, NULL, 0x4000, "", HFILL }},

            { &hf_sna_xid_3_gener_bind,
            { "Whole BIND PIU generated indicator",
                "sna.xid.type3.gener_bind", FT_BOOLEAN, 16, NULL, 0x2000,
                "Whole BIND PIU generated", HFILL }},

            { &hf_sna_xid_3_recve_bind,
            { "Whole BIND PIU required indicator",
                "sna.xid.type3.recve_bind", FT_BOOLEAN, 16, NULL, 0x1000,
                "Whole BIND PIU required", HFILL }},

            { &hf_sna_xid_3_actpu,
            { "ACTPU suppression indicator", "sna.xid.type3.actpu",
                FT_BOOLEAN, 16, NULL, 0x0080, "", HFILL }},

            { &hf_sna_xid_3_nwnode,
            { "Sender is network node", "sna.xid.type3.nwnode",
                FT_BOOLEAN, 16, NULL, 0x0040, "", HFILL }},

            { &hf_sna_xid_3_cp,
            { "Control Point Services", "sna.xid.type3.cp",
                FT_BOOLEAN, 16, NULL, 0x0020, "", HFILL }},

            { &hf_sna_xid_3_cpcp,
            { "CP-CP session support", "sna.xid.type3.cpcp",
                FT_BOOLEAN, 16, NULL, 0x0010, "", HFILL }},

            { &hf_sna_xid_3_state,
            { "XID exchange state indicator", "sna.xid.type3.state",
                FT_UINT16, BASE_HEX, VALS(sna_xid_3_state_vals),
                0x000c, "", HFILL }},

            { &hf_sna_xid_3_nonact,
            { "Nonactivation Exchange", "sna.xid.type3.nonact",
                FT_BOOLEAN, 16, NULL, 0x0002, "", HFILL }},

            { &hf_sna_xid_3_cpchange,
            { "CP name change support", "sna.xid.type3.cpchange",
                FT_BOOLEAN, 16, NULL, 0x0001, "", HFILL }},

            { &hf_sna_xid_3_10,
            { "XID Type 3 Byte 10", "sna.xid.type3.10", FT_UINT8, BASE_HEX,
                NULL, 0x0, "", HFILL }},

            { &hf_sna_xid_3_asend_bind,
            { "Adaptive BIND pacing support as sender",
                "sna.xid.type3.asend_bind", FT_BOOLEAN, 8, NULL, 0x80,
                "Pacing support as sender", HFILL }},

            { &hf_sna_xid_3_arecv_bind,
            { "Adaptive BIND pacing support as receiver",
                "sna.xid.type3.asend_recv", FT_BOOLEAN, 8, NULL, 0x40,
                "Pacing support as receive", HFILL }},

            { &hf_sna_xid_3_quiesce,
            { "Quiesce TG Request",
                "sna.xid.type3.quiesce", FT_BOOLEAN, 8, NULL, 0x20,
                "", HFILL }},

            { &hf_sna_xid_3_pucap,
            { "PU Capabilities",
                "sna.xid.type3.pucap", FT_BOOLEAN, 8, NULL, 0x10,
                "", HFILL }},

            { &hf_sna_xid_3_pbn,
            { "Peripheral Border Node",
                "sna.xid.type3.pbn", FT_BOOLEAN, 8, NULL, 0x08,
                "", HFILL }},

            { &hf_sna_xid_3_pacing,
            { "Qualifier for adaptive BIND pacing support",
                "sna.xid.type3.pacing", FT_UINT8, BASE_HEX, NULL, 0x03,
                "", HFILL }},

            { &hf_sna_xid_3_11,
            { "XID Type 3 Byte 11", "sna.xid.type3.11", FT_UINT8, BASE_HEX,
                NULL, 0x0, "", HFILL }},

            { &hf_sna_xid_3_tgshare,
            { "TG Sharing Prohibited Indicator",
                "sna.xid.type3.tgshare", FT_BOOLEAN, 8, NULL, 0x40,
                "", HFILL }},

            { &hf_sna_xid_3_dedsvc,
            { "Dedicated SVC Idicator",
                "sna.xid.type3.dedsvc", FT_BOOLEAN, 8, NULL, 0x20,
                "", HFILL }},

            { &hf_sna_xid_3_12,
            { "XID Type 3 Byte 12", "sna.xid.type3.12", FT_UINT8, BASE_HEX,
                NULL, 0x0, "", HFILL }},

            { &hf_sna_xid_3_negcsup,
            { "Negotiation Complete Supported",
                "sna.xid.type3.negcsup", FT_BOOLEAN, 8, NULL, 0x80,
                "", HFILL }},

            { &hf_sna_xid_3_negcomp,
            { "Negotiation Complete",
                "sna.xid.type3.negcomp", FT_BOOLEAN, 8, NULL, 0x40,
                "", HFILL }},

            { &hf_sna_xid_3_15,
            { "XID Type 3 Byte 15", "sna.xid.type3.15", FT_UINT8, BASE_HEX,
                NULL, 0x0, "", HFILL }},

            { &hf_sna_xid_3_partg,
            { "Parallel TG Support",
                "sna.xid.type3.partg", FT_BOOLEAN, 8, NULL, 0x80,
                "", HFILL }},

            { &hf_sna_xid_3_dlur,
            { "Dependent LU Requester Indicator",
                "sna.xid.type3.dlur", FT_BOOLEAN, 8, NULL, 0x40,
                "", HFILL }},

            { &hf_sna_xid_3_dlus,
            { "DLUS Served LU Registration Indicator",
                "sna.xid.type3.dlus", FT_BOOLEAN, 8, NULL, 0x20,
                "", HFILL }},

            { &hf_sna_xid_3_exbn,
            { "Extended HPR Border Node",
                "sna.xid.type3.exbn", FT_BOOLEAN, 8, NULL, 0x10,
                "", HFILL }},

            { &hf_sna_xid_3_genodai,
            { "Generalized ODAI Usage Option",
                "sna.xid.type3.genodai", FT_BOOLEAN, 8, NULL, 0x08,
                "", HFILL }},

            { &hf_sna_xid_3_branch,
            { "Branch Indicator", "sna.xid.type3.branch",
                FT_UINT8, BASE_HEX, VALS(sna_xid_3_branch_vals),
                0x06, "", HFILL }},

            { &hf_sna_xid_3_brnn,
            { "Option Set 1123 Indicator",
                "sna.xid.type3.brnn", FT_BOOLEAN, 8, NULL, 0x01,
                "", HFILL }},

            { &hf_sna_xid_3_tg,
            { "XID TG", "sna.xid.type3.tg", FT_UINT8, BASE_HEX, NULL, 0x0,
                "", HFILL }},

            { &hf_sna_xid_3_dlc,
            { "XID DLC", "sna.xid.type3.dlc", FT_UINT8, BASE_HEX, NULL, 0x0,
                "", HFILL }},

            { &hf_sna_xid_3_dlen,
            { "DLC Dependent Section Length", "sna.xid.type3.dlen",
                FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_control_len,
                { "Control Vector Length", "sna.control.len",
                FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},

                { &hf_sna_control_key,
                { "Control Vector Key", "sna.control.key",
                FT_UINT8, BASE_HEX, VALS(sna_control_vals), 0x0, "",
                HFILL }},

                { &hf_sna_control_hprkey,
                { "Control Vector HPR Key", "sna.control.hprkey",
                FT_UINT8, BASE_HEX, VALS(sna_control_hpr_vals), 0x0, "",
                HFILL }},
      
                { &hf_sna_control_05_delay,
                { "Channel Delay", "sna.control.05.delay",
                FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL }},
      
                { &hf_sna_control_05_type,
                { "Network Address Type", "sna.control.05.type",
                FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }},
      
                { &hf_sna_control_05_ptp,
                { "Point-to-point", "sna.control.05.ptp",
                FT_BOOLEAN, 8, NULL, 0x80, "", HFILL }},
      
                { &hf_sna_control_0e_type,
                { "Type", "sna.control.0e.type",
                FT_UINT8, BASE_HEX, VALS(sna_control_0e_type_vals),
                0, "", HFILL }},
      
                { &hf_sna_control_0e_value,
                { "Value", "sna.control.0e.value",
                FT_STRING, BASE_NONE, NULL, 0, "", HFILL }},
        };
      static gint *ett[] = {
            &ett_sna,
            &ett_sna_th,
            &ett_sna_th_fid,
            &ett_sna_nlp_nhdr,
            &ett_sna_nlp_nhdr_0,
            &ett_sna_nlp_nhdr_1,
            &ett_sna_nlp_thdr,
            &ett_sna_nlp_thdr_8,
            &ett_sna_nlp_thdr_9,
            &ett_sna_nlp_opti_un,
            &ett_sna_nlp_opti_0d,
            &ett_sna_nlp_opti_0d_4,
            &ett_sna_nlp_opti_0e,
            &ett_sna_nlp_opti_0e_stat,
            &ett_sna_nlp_opti_0e_absp,
            &ett_sna_nlp_opti_0f,
            &ett_sna_nlp_opti_10,
            &ett_sna_nlp_opti_12,
            &ett_sna_nlp_opti_14,
            &ett_sna_nlp_opti_14_si,
            &ett_sna_nlp_opti_14_si_2,
            &ett_sna_nlp_opti_14_rr,
            &ett_sna_nlp_opti_14_rr_2,
            &ett_sna_nlp_opti_22,
            &ett_sna_nlp_opti_22_2,
            &ett_sna_nlp_opti_22_3,
            &ett_sna_rh,
            &ett_sna_rh_0,
            &ett_sna_rh_1,
            &ett_sna_rh_2,
            &ett_sna_gds,
            &ett_sna_xid_0,
            &ett_sna_xid_id,
            &ett_sna_xid_3_8,
            &ett_sna_xid_3_10,
            &ett_sna_xid_3_11,
            &ett_sna_xid_3_12,
            &ett_sna_xid_3_15,
            &ett_sna_control_un,
            &ett_sna_control_05,
            &ett_sna_control_05hpr,
            &ett_sna_control_05hpr_type,
            &ett_sna_control_0e,
      };
      module_t *sna_module;

      proto_sna = proto_register_protocol("Systems Network Architecture",
          "SNA", "sna");
      proto_register_field_array(proto_sna, hf, array_length(hf));
      proto_register_subtree_array(ett, array_length(ett));
      register_dissector("sna", dissect_sna, proto_sna);

      proto_sna_xid = proto_register_protocol(
          "Systems Network Architecture XID", "SNA XID", "sna_xid");
      register_dissector("sna_xid", dissect_sna_xid, proto_sna_xid);

      /* Register configuration options */
      sna_module = prefs_register_protocol(proto_sna, NULL);
      prefs_register_bool_preference(sna_module, "defragment",
            "Reassemble fragmented BIUs",
            "Whether fragmented BIUs should be reassembled",
            &sna_defragment);
}

void
proto_reg_handoff_sna(void)
{
      dissector_handle_t sna_handle;
      dissector_handle_t sna_xid_handle;

      sna_handle = find_dissector("sna");
      sna_xid_handle = find_dissector("sna_xid");
      dissector_add("llc.dsap", SAP_SNA_PATHCTRL, sna_handle);
      dissector_add("llc.dsap", SAP_SNA1, sna_handle);
      dissector_add("llc.dsap", SAP_SNA2, sna_handle);
      dissector_add("llc.dsap", SAP_SNA3, sna_handle);
      dissector_add("llc.xid_dsap", SAP_SNA_PATHCTRL, sna_xid_handle);
      dissector_add("llc.xid_dsap", SAP_SNA1, sna_xid_handle);
      dissector_add("llc.xid_dsap", SAP_SNA2, sna_xid_handle);
      dissector_add("llc.xid_dsap", SAP_SNA3, sna_xid_handle);
      /* RFC 2043 */
      dissector_add("ppp.protocol", PPP_SNA, sna_handle);
      data_handle = find_dissector("data");

      register_init_routine(sna_init);
}

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