epan/dissectors/packet-ieee802a.c

   1 /* packet-ieee802a.c
   2  * Routines for IEEE 802a
   3  *
   4  * Wireshark - Network traffic analyzer
   5  * By Gerald Combs <gerald@wireshark.org>
   6  * Copyright 1998 Gerald Combs
   7  *
   8  * SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #include "config.h"
  12
  13 #include <epan/packet.h>
  14 #include <epan/addr_resolv.h>
  15 #include <epan/etypes.h>
  16
  17 #include "packet-ieee802a.h"
  18
  19 void proto_register_ieee802a(void);
  20 void proto_reg_handoff_ieee802a(void);
  21
  22 static dissector_handle_t ieee802a_handle;
  23
  24 static int proto_ieee802a;
  25 static int hf_ieee802a_oui;
  26 static int hf_ieee802a_pid;
  27
  28 static int ett_ieee802a;
  29
  30 /*
  31  * Hash table for translating OUIs to a dissector table/field info pair;
  32  * the dissector table maps PID values to dissectors, and the field
  33  * corresponds to the PID for that OUI.
  34  */
  35 typedef struct {
  36         dissector_table_t table;
  37         hf_register_info *field_info;
  38 } oui_info_t;
  39
  40 static GHashTable *oui_info_table;
  41
  42 /*
  43  * Add an entry for a new OUI.
  44  */
  45 void
  46 ieee802a_add_oui(uint32_t oui, const char *table_name, const char *table_ui_name,
  47                  hf_register_info *hf_item, const int proto)
  48 {
  49         oui_info_t *new_info;
  50
  51         new_info = g_new(oui_info_t, 1);
  52         new_info->table = register_dissector_table(table_name,
  53             table_ui_name, proto, FT_UINT16, BASE_HEX);
  54         new_info->field_info = hf_item;
  55
  56         /*
  57          * Create the hash table for OUI information, if it doesn't
  58          * already exist.
  59          */
  60         if (oui_info_table == NULL) {
  61                 oui_info_table = g_hash_table_new_full(g_direct_hash,
  62                     g_direct_equal, NULL, g_free);
  63         }
  64         g_hash_table_insert(oui_info_table, GUINT_TO_POINTER(oui), new_info);
  65 }
  66
  67 static int
  68 dissect_ieee802a(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  69 {
  70         proto_tree      *ieee802a_tree;
  71         proto_item      *ti;
  72         tvbuff_t        *next_tvb;
  73         const char      *manuf;
  74         uint32_t                oui32;
  75         uint16_t                pid;
  76         oui_info_t      *oui_info;
  77         dissector_table_t subdissector_table;
  78         int             hf;
  79
  80         col_set_str(pinfo->cinfo, COL_PROTOCOL, "IEEE802a");
  81         col_clear(pinfo->cinfo, COL_INFO);
  82
  83         ti = proto_tree_add_item(tree, proto_ieee802a, tvb, 0, 5, ENC_NA);
  84         ieee802a_tree = proto_item_add_subtree(ti, ett_ieee802a);
  85
  86         proto_tree_add_item_ret_uint(ieee802a_tree, hf_ieee802a_oui, tvb, 0, 3, ENC_BIG_ENDIAN, &oui32);
  87         manuf = uint_get_manuf_name_if_known(oui32);
  88         pid = tvb_get_ntohs(tvb, 3);
  89
  90         col_add_fstr(pinfo->cinfo, COL_INFO, "OUI %s (%s), PID 0x%04X",
  91                 tvb_bytes_to_str_punct(pinfo->pool, tvb, 0, 3, ':'),
  92                 manuf ? manuf : "Unknown", pid);
  93
  94         /*
  95          * Do we have information for this OUI?
  96          */
  97         if (oui_info_table != NULL &&
  98             (oui_info = (oui_info_t *)g_hash_table_lookup(oui_info_table,
  99               GUINT_TO_POINTER(oui32))) != NULL) {
 100                 /*
 101                  * Yes - use it.
 102                  */
 103                 hf = *oui_info->field_info->p_id;
 104                 subdissector_table = oui_info->table;
 105         } else {
 106                 /*
 107                  * No, use hf_ieee802a_pid for the PID and just dissect
 108                  * the payload as data.
 109                  */
 110                 hf = hf_ieee802a_pid;
 111                 subdissector_table = NULL;
 112         }
 113
 114         proto_tree_add_uint(ieee802a_tree, hf, tvb, 3, 2, pid);
 115         next_tvb = tvb_new_subset_remaining(tvb, 5);
 116         if ((subdissector_table == NULL) ||
 117                 /* do lookup with the subdissector table */
 118                 (!dissector_try_uint(subdissector_table, pid, next_tvb, pinfo, tree))) {
 119                         call_data_dissector(next_tvb, pinfo, tree);
 120         }
 121         return tvb_captured_length(tvb);
 122 }
 123
 124 static void
 125 ieee802a_shutdown(void)
 126 {
 127         g_hash_table_destroy(oui_info_table);
 128 }
 129
 130 void
 131 proto_register_ieee802a(void)
 132 {
 133         static hf_register_info hf[] = {
 134                 { &hf_ieee802a_oui,
 135                   { "Organization Code",        "ieee802a.oui", FT_UINT24, BASE_OUI,
 136                     NULL, 0x0, NULL, HFILL }},
 137
 138                 { &hf_ieee802a_pid,
 139                   { "Protocol ID", "ieee802a.pid", FT_UINT16, BASE_HEX,
 140                     NULL, 0x0, NULL, HFILL }}
 141         };
 142         static int *ett[] = {
 143                 &ett_ieee802a,
 144         };
 145
 146         proto_ieee802a = proto_register_protocol("IEEE802a OUI Extended Ethertype", "IEEE802a", "ieee802a");
 147         proto_register_field_array(proto_ieee802a, hf, array_length(hf));
 148         proto_register_subtree_array(ett, array_length(ett));
 149         register_shutdown_routine(ieee802a_shutdown);
 150
 151         ieee802a_handle = register_dissector("ieee802a", dissect_ieee802a, proto_ieee802a);
 152 }
 153
 154 static void
 155 register_hf(void *key _U_, void *value, void *user_data _U_)
 156 {
 157         oui_info_t *info = (oui_info_t *)value;
 158
 159         proto_register_field_array(proto_ieee802a, info->field_info, 1);
 160 }
 161
 162 void
 163 proto_reg_handoff_ieee802a(void)
 164 {
 165         dissector_add_uint("ethertype", ETHERTYPE_IEEE802_OUI_EXTENDED,
 166             ieee802a_handle);
 167
 168         /*
 169          * Register all the fields for PIDs for various OUIs.
 170          */
 171         if (oui_info_table != NULL)
 172                 g_hash_table_foreach(oui_info_table, register_hf, NULL);
 173 }
 174
 175 /*
 176  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 177  *
 178  * Local variables:
 179  * c-basic-offset: 8
 180  * tab-width: 8
 181  * indent-tabs-mode: t
 182  * End:
 183  *
 184  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 185  * :indentSize=8:tabSize=8:noTabs=false:
 186  */