epan/dissectors/packet-pw-oam.c

   1 /* packet-pw-oam.c
   2  *
   3  * Routines for Pseudowire Status for static pseudowires : RFC 6478
   4  *
   5  * (c) Copyright 2012, Krishnamurthy Mayya <krishnamurthymayya@gmail.com>
   6  *                     Nikitha Malgi <nikitha01@gmail.com>
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * SPDX-License-Identifier: GPL-2.0-or-later
  13  */
  14
  15 #include "config.h"
  16 #include <epan/packet.h>
  17 #include "packet-mpls.h"
  18
  19 void proto_register_pw_oam(void);
  20 void proto_reg_handoff_pw_oam(void);
  21
  22 static dissector_handle_t pw_oam_handle;
  23
  24 /* MPLS-TP FM protocol specific variables */
  25 static int proto_pw_oam;
  26 static int ett_pw_oam;
  27 static int ett_pw_oam_flags;
  28 static int ett_pw_oam_tlv_tree;
  29
  30 static int hf_pw_oam_tlv_reserved;
  31 static int hf_pw_oam_tlv_type;
  32 static int hf_pw_oam_total_tlv_len;
  33 static int hf_pw_oam_code;
  34 static int hf_pw_oam_flags;
  35 static int hf_pw_oam_flags_a;
  36 static int hf_pw_oam_refresh_timer;
  37 static int hf_pw_oam_tlv_len;
  38
  39 static const value_string pw_oam_code[] = {
  40   {0x00000002, "Local Attachment Circuit(ingress) Receive Fault"},
  41   {0x00000004, "Local Attachment Circuit(egress) Transmit Fault"},
  42   {0x00000020, "PW Forwarding Standby"},
  43   {0x00000040, "Request Switchover to this PW"},
  44   {0, NULL}
  45 };
  46
  47 /* PW-Status TLV dissector */
  48 static void
  49 dissect_pw_status_tlv (tvbuff_t *tvb, proto_tree *tree, int offset)
  50 {
  51   proto_item *ti;
  52   proto_tree *pw_oam_tlv_tree;
  53
  54
  55   ti = proto_tree_add_protocol_format (tree, proto_pw_oam, tvb, offset, 8,
  56                                        "Pseudo-Wire Status TLV");
  57
  58
  59   if (!tree)
  60     return;
  61
  62   pw_oam_tlv_tree = proto_item_add_subtree (ti, ett_pw_oam_tlv_tree);
  63
  64   proto_tree_add_item (pw_oam_tlv_tree, hf_pw_oam_tlv_reserved, tvb, offset,
  65                                     2, ENC_BIG_ENDIAN);
  66   proto_tree_add_item (pw_oam_tlv_tree, hf_pw_oam_tlv_type, tvb, offset,
  67                                     2, ENC_BIG_ENDIAN);
  68   offset = offset + 2;
  69
  70   proto_tree_add_item (pw_oam_tlv_tree, hf_pw_oam_tlv_len, tvb, offset,
  71                                     2, ENC_BIG_ENDIAN);
  72   offset = offset + 2;
  73   proto_tree_add_item (pw_oam_tlv_tree, hf_pw_oam_code, tvb, offset,
  74                                     4, ENC_BIG_ENDIAN);
  75   /*offset = offset + 4;*/
  76
  77   return ;
  78 }
  79
  80 /* Dissector for PW OAM protocol: RFC 6478 */
  81 static int
  82 dissect_pw_oam(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  83 {
  84   proto_item  *ti = NULL, *ti_flags = NULL;
  85   proto_tree  *pw_oam_tree = NULL, *pw_oam_flags = NULL;
  86
  87   uint8_t offset        = 0;
  88   uint16_t pw_tlv_type   = 0;
  89
  90   col_set_str(pinfo->cinfo, COL_PROTOCOL, "PW OAM");
  91   col_clear(pinfo->cinfo, COL_INFO);
  92
  93   if (!tree)
  94     return tvb_captured_length(tvb);
  95
  96   ti = proto_tree_add_item(tree, proto_pw_oam, tvb, 0, -1, ENC_NA);
  97
  98   pw_oam_tree = proto_item_add_subtree (ti, ett_pw_oam);
  99
 100   /* Refresh-Timer field */
 101   proto_tree_add_item (pw_oam_tree, hf_pw_oam_refresh_timer, tvb, offset,
 102                        2, ENC_BIG_ENDIAN);
 103   offset = offset + 2;
 104
 105   /* Total-TLV length */
 106   proto_tree_add_item (pw_oam_tree, hf_pw_oam_total_tlv_len, tvb, offset,
 107                        1, ENC_BIG_ENDIAN);
 108   offset = offset + 1;
 109
 110   /* Flags field */
 111   ti_flags = proto_tree_add_item (pw_oam_tree, hf_pw_oam_flags, tvb,
 112                                   offset, 1, ENC_BIG_ENDIAN);
 113   pw_oam_flags = proto_item_add_subtree(ti_flags, ett_pw_oam_flags);
 114   proto_tree_add_item (pw_oam_flags, hf_pw_oam_flags_a, tvb, offset, 1, ENC_BIG_ENDIAN);
 115
 116   offset = offset + 1;
 117   pw_tlv_type = tvb_get_ntohs (tvb, offset);
 118
 119   /* TLVs  */
 120   switch (pw_tlv_type)
 121     {
 122       /* The switch cases below have to be based on the LDP-name space.
 123           http://www.iana.org/assignments/ldp-namespaces/ldp-namespaces.xml */
 124
 125       case 0x096A: /* PW-Status TLV */
 126         dissect_pw_status_tlv (tvb, tree, offset);
 127         break;
 128
 129       default:
 130         break;
 131     }
 132
 133   return tvb_captured_length(tvb);
 134 }
 135
 136 void
 137 proto_register_pw_oam(void)
 138 {
 139   static hf_register_info hf[] = {
 140
 141     {&hf_pw_oam_refresh_timer,
 142       {"Refresh-Timer", "pw_oam.refresh-timer", FT_UINT16,
 143         BASE_HEX, NULL, 0x0, NULL, HFILL }},
 144
 145     {&hf_pw_oam_total_tlv_len,
 146       {"TLV Length", "pw_oam.total-tlv-len", FT_UINT8,
 147         BASE_HEX, NULL, 0x0, NULL, HFILL }},
 148
 149     {&hf_pw_oam_flags,
 150       {"Flags", "pw_oam.flags", FT_UINT8,
 151         BASE_HEX, NULL, 0x0, "OAM Flags", HFILL }},
 152
 153     {&hf_pw_oam_flags_a,
 154       {"Acknowledgement", "pw_oam.flags_a",
 155         FT_BOOLEAN, 8, NULL, 0x80, "ACK bit", HFILL}
 156     },
 157
 158     {&hf_pw_oam_tlv_reserved,
 159       {"Reserved", "pw_oam.tlv-reserved",
 160         FT_UINT16, BASE_HEX, NULL, 0xC000, NULL, HFILL}
 161     },
 162
 163     {&hf_pw_oam_tlv_type,
 164       {"TLV Type", "pw_oam.tlv-type",
 165         FT_UINT16, BASE_HEX, NULL, 0x3FFF, NULL, HFILL}
 166     },
 167
 168     {&hf_pw_oam_tlv_len,
 169       {"TLV Length", "pw_oam.tlv-len",
 170         FT_UINT16, BASE_HEX, NULL, 0x00, NULL, HFILL}
 171     },
 172
 173     {&hf_pw_oam_code,
 174       {"Status code", "pw_oam.code", FT_UINT32,
 175         BASE_HEX, VALS(pw_oam_code), 0x0, "PW Status Code", HFILL }
 176     },
 177
 178   };
 179
 180   static int *ett[] = {
 181     &ett_pw_oam,
 182     &ett_pw_oam_tlv_tree,
 183     &ett_pw_oam_flags,
 184   };
 185
 186   proto_pw_oam =
 187     proto_register_protocol("Pseudo-Wire OAM", "PW-OAM "
 188         "Pseudo-Wire OAM Protocol",
 189         "pw_oam");
 190
 191   proto_register_field_array (proto_pw_oam, hf, array_length(hf));
 192   proto_register_subtree_array (ett, array_length(ett));
 193
 194   pw_oam_handle = register_dissector ("pw_oam",  dissect_pw_oam, proto_pw_oam);
 195 }
 196
 197 void
 198 proto_reg_handoff_pw_oam(void)
 199 {
 200   dissector_add_uint("pwach.channel_type", PW_ACH_TYPE_PW_OAM, pw_oam_handle);
 201 }
 202
 203 /*
 204  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 205  *
 206  * Local variables:
 207  * c-basic-offset: 2
 208  * tab-width: 8
 209  * indent-tabs-mode: nil
 210  * End:
 211  *
 212  * vi: set shiftwidth=2 tabstop=8 expandtab:
 213  * :indentSize=2:tabSize=8:noTabs=true:
 214  */