epan/xdlc.h

   1 /* xdlc.h
   2  * Define *DLC frame types, and routine to dissect the control field of
   3  * a *DLC frame.
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #ifndef __XDLC_H__
  13 #define __XDLC_H__
  14
  15 #include "ws_symbol_export.h"
  16
  17 /** @file
  18  * Define *DLC frame types, and routine to dissect the control field of
  19  * a *DLC frame.
  20  */
  21 /*
  22  * Low-order bits of first (extended) or only (basic) octet of control
  23  * field, specifying the frame type.
  24  */
  25 #define XDLC_I_MASK             0x01    /**< Mask to test for I or not I */
  26 #define XDLC_I                  0x00    /**< Information frames */
  27 #define XDLC_S_U_MASK           0x03    /**< Mask to test for S or U */
  28 #define XDLC_S                  0x01    /**< Supervisory frames */
  29 #define XDLC_U                  0x03    /**< Unnumbered frames */
  30
  31 /*
  32  * N(S) and N(R) fields, in basic and extended operation.
  33  */
  34 #define XDLC_N_R_MASK           0xE0    /**< basic */
  35 #define XDLC_N_R_SHIFT          5
  36 #define XDLC_N_R_EXT_MASK       0xFE00  /**< extended */
  37 #define XDLC_N_R_EXT_SHIFT      9
  38 #define XDLC_N_S_MASK           0x0E    /**< basic */
  39 #define XDLC_N_S_SHIFT          1
  40 #define XDLC_N_S_EXT_MASK       0x00FE  /**< extended */
  41 #define XDLC_N_S_EXT_SHIFT      1
  42
  43 /*
  44  * Poll/Final bit, in basic and extended operation.
  45  */
  46 #define XDLC_P_F                0x10    /**< basic */
  47 #define XDLC_P_F_EXT    0x0100  /**< extended */
  48
  49 /*
  50  * S-format frame types.
  51  */
  52 #define XDLC_S_FTYPE_MASK       0x0C
  53 #define XDLC_RR                 0x00    /**< Receiver ready */
  54 #define XDLC_RNR                0x04    /**< Receiver not ready */
  55 #define XDLC_REJ                0x08    /**< Reject */
  56 #define XDLC_SREJ               0x0C    /**< Selective reject */
  57
  58 /*
  59  * U-format modifiers.
  60  */
  61 #define XDLC_U_MODIFIER_MASK    0xEC
  62 #define XDLC_UI         0x00    /**< Unnumbered Information */
  63 #define XDLC_UP         0x20    /**< Unnumbered Poll */
  64 #define XDLC_DISC       0x40    /**< Disconnect (command) */
  65 #define XDLC_RD         0x40    /**< Request Disconnect (response) */
  66 #define XDLC_UA         0x60    /**< Unnumbered Acknowledge */
  67 #define XDLC_SNRM       0x80    /**< Set Normal Response Mode */
  68 #define XDLC_TEST       0xE0    /**< Test */
  69 #define XDLC_SIM        0x04    /**< Set Initialization Mode (command) */
  70 #define XDLC_RIM        0x04    /**< Request Initialization Mode (response) */
  71 #define XDLC_FRMR       0x84    /**< Frame reject */
  72 #define XDLC_CFGR       0xC4    /**< Configure */
  73 #define XDLC_SARM       0x0C    /**< Set Asynchronous Response Mode (command) */
  74 #define XDLC_DM         0x0C    /**< Disconnected mode (response) */
  75 #define XDLC_SABM       0x2C    /**< Set Asynchronous Balanced Mode */
  76 #define XDLC_SARME      0x4C    /**< Set Asynchronous Response Mode Extended */
  77 #define XDLC_SABME      0x6C    /**< Set Asynchronous Balanced Mode Extended */
  78 #define XDLC_RESET      0x8C    /**< Reset */
  79 #define XDLC_XID        0xAC    /**< Exchange identification */
  80 #define XDLC_SNRME      0xCC    /**< Set Normal Response Mode Extended */
  81 #define XDLC_BCN        0xEC    /**< Beacon */
  82
  83 /**
  84  * This macro takes the control field of an xDLC frame, as returned by
  85  * "get_xdlc_control()" or "dissect_xdlc_control()", and evaluates to
  86  * true if the frame is an "information" frame and false if it isn't.
  87  * Note that frames other than information frames can have data in them,
  88  * e.g. TEST frames.
  89  */
  90 #define XDLC_IS_INFORMATION(control) \
  91         (((control) & XDLC_I_MASK) == XDLC_I || (control) == (XDLC_UI|XDLC_U))
  92
  93 /**
  94  * This macro takes the control field of an xDLC frame, and a flag saying
  95  * whether we're doing basic or extended operation, and evaluates to
  96  * the length of that field (if it's an Unnumbered frame, or we're not
  97  * in extended mode, it's 1 byte long, otherwise it's 2 bytes long).
  98  */
  99 #define XDLC_CONTROL_LEN(control, is_extended) \
 100         ((((control) & XDLC_S_U_MASK) == XDLC_U || !(is_extended)) ? 1 : 2)
 101
 102 /**
 103  * Structure containing pointers to hf_ values for various subfields of
 104  * the control field.
 105  */
 106 typedef struct {
 107         int     *hf_xdlc_n_r;
 108         int     *hf_xdlc_n_s;
 109         int     *hf_xdlc_p;
 110         int     *hf_xdlc_f;
 111         int     *hf_xdlc_s_ftype;
 112         int     *hf_xdlc_u_modifier_cmd;
 113         int     *hf_xdlc_u_modifier_resp;
 114         int     *hf_xdlc_ftype_i;
 115         int     *hf_xdlc_ftype_s_u;
 116 } xdlc_cf_items;
 117
 118 extern const value_string ftype_vals[];
 119 extern const value_string stype_vals[];
 120 extern const value_string modifier_vals_cmd[];
 121 extern const value_string modifier_vals_resp[];
 122
 123 extern int get_xdlc_control(const uint8_t *pd, int offset, bool is_extended);
 124
 125 WS_DLL_PUBLIC int dissect_xdlc_control(tvbuff_t *tvb, int offset, packet_info *pinfo,
 126   proto_tree *xdlc_tree, int hf_xdlc_control, int ett_xdlc_control,
 127   const xdlc_cf_items *cf_items_nonext, const xdlc_cf_items *cf_items_ext,
 128   const value_string *u_modifier_short_vals_cmd,
 129   const value_string *u_modifier_short_vals_resp, bool is_response,
 130   bool is_extended, bool append_info);
 131
 132 #endif