/src/wireshark/epan/dissectors/packet-pppoe.c

Source
/* packet-pppoe.c
 * Routines for PPP Over Ethernet (PPPoE) packet disassembly (RFC2516)
 * Up to date with http://www.iana.org/assignments/pppoe-parameters (2008-04-30)
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <epan/packet.h>
#include <epan/etypes.h>
#include <epan/prefs.h>
#include <epan/expert.h>
#include <wiretap/wtap.h>
#include "packet-ppp.h"


void proto_register_pppoed(void);
void proto_reg_handoff_pppoed(void);
void proto_register_pppoes(void);
void proto_register_pppoe(void);
void proto_reg_handoff_pppoes(void);

static dissector_handle_t pppoed_handle;
static dissector_handle_t pppoes_handle;

static int proto_pppoed;

/* Common to session and discovery protocols */
static int hf_pppoe_version;
static int hf_pppoe_type;
static int hf_pppoe_code;
static int hf_pppoe_session_id;
static int hf_pppoe_payload_length;

/* Discovery protocol fields */
static int hf_pppoed_tags;
static int hf_pppoed_tag;
static int hf_pppoed_tag_length;
static int hf_pppoed_tag_length_8;
static int hf_pppoed_tag_unknown_data;
static int hf_pppoed_tag_service_name;
static int hf_pppoed_tag_ac_name;
static int hf_pppoed_tag_host_uniq;
static int hf_pppoed_tag_ac_cookie;
static int hf_pppoed_tag_vendor_id;
static int hf_pppoed_tag_vendor_unspecified;
static int hf_pppoed_tag_vspec_tags;
static int hf_pppoed_tag_vspec_tag;
static int hf_pppoed_tag_vspec_circuit_id;
static int hf_pppoed_tag_vspec_remote_id;
static int hf_pppoed_tag_vspec_act_data_rate_up;
static int hf_pppoed_tag_vspec_act_data_rate_down;
static int hf_pppoed_tag_vspec_min_data_rate_up;
static int hf_pppoed_tag_vspec_min_data_rate_down;
static int hf_pppoed_tag_vspec_attainable_data_rate_up;
static int hf_pppoed_tag_vspec_attainable_data_rate_down;
static int hf_pppoed_tag_vspec_max_data_rate_up;
static int hf_pppoed_tag_vspec_max_data_rate_down;
static int hf_pppoed_tag_vspec_min_data_rate_up_lp;
static int hf_pppoed_tag_vspec_min_data_rate_down_lp;
static int hf_pppoed_tag_vspec_max_int_delay_up;
static int hf_pppoed_tag_vspec_act_int_delay_up;
static int hf_pppoed_tag_vspec_max_int_delay_down;
static int hf_pppoed_tag_vspec_act_int_delay_down;
static int hf_pppoed_tag_vspec_access_loop_encapsulation;
static int hf_pppoed_tag_vspec_access_loop_encap_data_link;
static int hf_pppoed_tag_vspec_access_loop_encap_encap_1;
static int hf_pppoed_tag_vspec_access_loop_encap_encap_2;
static int hf_pppoed_tag_credits;
static int hf_pppoed_tag_credits_fcn;
static int hf_pppoed_tag_credits_bcn;
static int hf_pppoed_tag_metrics;
static int hf_pppoed_tag_metrics_r;
static int hf_pppoed_tag_metrics_rlq;
static int hf_pppoed_tag_metrics_resource;
static int hf_pppoed_tag_metrics_latency;
static int hf_pppoed_tag_metrics_curr_drate;
static int hf_pppoed_tag_metrics_max_drate;
static int hf_pppoed_tag_mdr_units;
static int hf_pppoed_tag_cdr_units;
static int hf_pppoed_tag_seq_num;
static int hf_pppoed_tag_cred_scale;
static int hf_pppoed_tag_relay_session_id;
static int hf_pppoed_tag_hurl;
static int hf_pppoed_tag_motm;
static int hf_pppoed_tag_max_payload;
static int hf_pppoed_tag_ip_route_add;
static int hf_pppoed_tag_service_name_error;
static int hf_pppoed_tag_ac_system_error;
static int hf_pppoed_tag_generic_error;

/* Session protocol fields */
static int hf_pppoes_tags;
/* static int hf_pppoes_tag; */
/* static int hf_pppoes_tag_credits; */
static int hf_pppoes_tag_credits_fcn;
static int hf_pppoes_tag_credits_bcn;

/* Session protocol fields */

static int ett_pppoed;
static int ett_pppoed_tags;
static int ett_pppoed_tag_vspec_dslf_access_loop_encaps;

static int proto_pppoes;

static int ett_pppoes;
static int ett_pppoes_tags;

static expert_field ei_pppoe_payload_length;
static expert_field ei_pppoe_tag_length;

/* PPPoE parent fields */

static int proto_pppoe;
static int ett_pppoe;


/* Handle for calling for ppp dissector to handle session data */
static dissector_handle_t ppp_handle;


/* Preference for showing discovery tag values and lengths */
static bool global_pppoe_show_tags_and_lengths;


#define PPPOE_CODE_SESSION    0x00
#define PPPOE_CODE_PADO       0x07
#define PPPOE_CODE_PADI       0x09
#define PPPOE_CODE_PADG       0x0a
#define PPPOE_CODE_PADC       0x0b
#define PPPOE_CODE_PADQ       0x0c
#define PPPOE_CODE_PADR       0x19
#define PPPOE_CODE_PADS       0x65
#define PPPOE_CODE_PADT       0xa7
#define PPPOE_CODE_PADM       0xd3
#define PPPOE_CODE_PADN       0xd4

#define PPPOE_TAG_EOL         0x0000
#define PPPOE_TAG_SVC_NAME    0x0101
#define PPPOE_TAG_AC_NAME     0x0102
#define PPPOE_TAG_HOST_UNIQ   0x0103
#define PPPOE_TAG_AC_COOKIE   0x0104
#define PPPOE_TAG_VENDOR      0x0105
#define PPPOE_TAG_CREDITS     0x0106
#define PPPOE_TAG_METRICS     0x0107
#define PPPOE_TAG_SEQ_NUM     0x0108
#define PPPOE_TAG_CRED_SCALE  0x0109
#define PPPOE_TAG_RELAY_ID    0x0110
#define PPPOE_TAG_HURL        0x0111
#define PPPOE_TAG_MOTM        0x0112
#define PPPOE_TAG_MAX_PAYLD   0x0120
#define PPPOE_TAG_IP_RT_ADD   0x0121
#define PPPOE_TAG_SVC_ERR     0x0201
#define PPPOE_TAG_AC_ERR      0x0202
#define PPPOE_TAG_GENERIC_ERR 0x0203

#define PPPOE_VENDOR_ID_DSLF  3561

#define PPPOE_TAG_VSPEC_DSLF_CIRCUIT_ID                0x01
#define PPPOE_TAG_VSPEC_DSLF_REMOTE_ID                 0x02
#define PPPOE_TAG_VSPEC_DSLF_ACT_DATA_RATE_UP          0x81
#define PPPOE_TAG_VSPEC_DSLF_ACT_DATA_RATE_DOWN        0x82
#define PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_UP          0x83
#define PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_DOWN        0x84
#define PPPOE_TAG_VSPEC_DSLF_ATTAINABLE_DATA_RATE_UP   0x85
#define PPPOE_TAG_VSPEC_DSLF_ATTAINABLE_DATA_RATE_DOWN 0x86
#define PPPOE_TAG_VSPEC_DSLF_MAX_DATA_RATE_UP          0x87
#define PPPOE_TAG_VSPEC_DSLF_MAX_DATA_RATE_DOWN        0x88
#define PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_UP_LP       0x89
#define PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_DOWN_LP     0x8a
#define PPPOE_TAG_VSPEC_DSLF_MAX_INT_DELAY_UP          0x8b
#define PPPOE_TAG_VSPEC_DSLF_ACT_INT_DELAY_UP          0x8c
#define PPPOE_TAG_VSPEC_DSLF_MAX_INT_DELAY_DOWN        0x8d
#define PPPOE_TAG_VSPEC_DSLF_ACT_INT_DELAY_DOWN        0x8e
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAPSULATION 0x90

#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_DATA_LINK_ATM 0x00
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_DATA_LINK_ETH 0x01

#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_NA                0x00
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_UNTAGGED_ETH      0x01
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_SINGLE_TAGGED_ETH 0x02
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_DOUBLE_TAGGED_ETH 0x03

#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_NA                             0x00
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_PPPOA_LLC                      0x01
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_PPPOA_NULL                     0x02
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_IPOA_LLC                       0x03
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_IPOA_NULL                      0x04
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_LLC_WITH_FCS     0x05
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_LLC_WITHOUT_FCS  0x06
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_NULL_WITH_FCS    0x07
#define PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_NULL_WITHOUT_FCS 0x08

#define PPPOE_CDR_MASK        0x0006
#define PPPOE_MDR_MASK        0x0018
#define PPPOE_RCV_ONLY_MASK   0x0001

#define PPPOE_SCALE_KBPS      0x00
#define PPPOE_SCALE_MBPS      0x01
#define PPPOE_SCALE_GBPS      0x02
#define PPPOE_SCALE_TBPS      0x03


static const value_string code_vals[] = {
  {PPPOE_CODE_SESSION, "Session Data"                             },
  {PPPOE_CODE_PADO, "Active Discovery Offer (PADO)"               },
  {PPPOE_CODE_PADI, "Active Discovery Initiation (PADI)"          },
  {PPPOE_CODE_PADG, "Active Discovery Session-Grant (PADG)"       },
  {PPPOE_CODE_PADC, "Active Discovery Session-Credit Resp.(PADC)" },
  {PPPOE_CODE_PADQ, "Active Discovery Quality (PADQ)"             },
  {PPPOE_CODE_PADR, "Active Discovery Request (PADR)"             },
  {PPPOE_CODE_PADS, "Active Discovery Session-confirmation (PADS)"},
  {PPPOE_CODE_PADT, "Active Discovery Terminate (PADT)"           },
  {PPPOE_CODE_PADM, "Active Discovery Message (PADM)"             },
  {PPPOE_CODE_PADN, "Active Discovery Network (PADN)"             },
  {0,               NULL                                          }
};


static const value_string tag_vals[] = {
  {PPPOE_TAG_EOL,        "End-Of-List"       },
  {PPPOE_TAG_SVC_NAME,   "Service-Name"      },
  {PPPOE_TAG_AC_NAME,    "AC-Name"           },
  {PPPOE_TAG_HOST_UNIQ,  "Host-Uniq"         },
  {PPPOE_TAG_AC_COOKIE,  "AC-Cookie"         },
  {PPPOE_TAG_VENDOR,     "Vendor-Specific"   },
  {PPPOE_TAG_CREDITS,    "Credits"           },
  {PPPOE_TAG_METRICS,    "Metrics"           },
  {PPPOE_TAG_SEQ_NUM,    "Sequence Number"    },
  {PPPOE_TAG_CRED_SCALE, "Credit Scale Factor"},
  {PPPOE_TAG_RELAY_ID,   "Relay-Session-Id"  },
  {PPPOE_TAG_HURL,       "HURL"              },
  {PPPOE_TAG_MOTM,       "MOTM"              },
  {PPPOE_TAG_MAX_PAYLD,  "PPP-Max-Payload"   },
  {PPPOE_TAG_IP_RT_ADD,  "IP Route Add"      },
  {PPPOE_TAG_SVC_ERR,    "Service-Name-Error"},
  {PPPOE_TAG_AC_ERR,     "AC-System-Error"   },
  {PPPOE_TAG_GENERIC_ERR,"Generic-Error"     },
  {0,                    NULL                }
};

static const value_string vspec_tag_vals[] = {
  {PPPOE_TAG_VSPEC_DSLF_CIRCUIT_ID,                "Circuit-ID"                    },
  {PPPOE_TAG_VSPEC_DSLF_REMOTE_ID,                 "Remote-ID"                     },
  {PPPOE_TAG_VSPEC_DSLF_ACT_DATA_RATE_UP,          "Actual-Data-Rate-Up"           },
  {PPPOE_TAG_VSPEC_DSLF_ACT_DATA_RATE_DOWN,        "Actual-Data-Rate-Down"         },
  {PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_UP,          "Min-Data-Rate-Up"              },
  {PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_DOWN,        "Min-Data-Rate-Down"            },
  {PPPOE_TAG_VSPEC_DSLF_ATTAINABLE_DATA_RATE_UP,   "Attainable-Data-Rate-Up"       },
  {PPPOE_TAG_VSPEC_DSLF_ATTAINABLE_DATA_RATE_DOWN, "Attainable-Data-Rate-Down"     },
  {PPPOE_TAG_VSPEC_DSLF_MAX_DATA_RATE_UP,          "Max-Data-Rate-Up"              },
  {PPPOE_TAG_VSPEC_DSLF_MAX_DATA_RATE_DOWN,        "Max-Data-Rate-Down"            },
  {PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_UP_LP,       "Min-Data-Rate-Up-Low-Power"    },
  {PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_DOWN_LP,     "Min-Data-Rate-Down-Low-Power"  },
  {PPPOE_TAG_VSPEC_DSLF_MAX_INT_DELAY_UP,          "Max-Interleaving-Delay-Up"     },
  {PPPOE_TAG_VSPEC_DSLF_ACT_INT_DELAY_UP,          "Actual-Interleaving-Delay-Up"  },
  {PPPOE_TAG_VSPEC_DSLF_MAX_INT_DELAY_DOWN,        "Max-Interleaving-Delay-Down"   },
  {PPPOE_TAG_VSPEC_DSLF_ACT_INT_DELAY_DOWN,        "Actual-Interleaving-Delay-Down"},
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAPSULATION, "Access-Loop-Encapsulation"     },
  {0,                                              NULL                            }
};

static const value_string vspec_tag_dslf_access_loop_encap_data_link_vals[] = {
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_DATA_LINK_ATM, "ATM AAL5"},
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_DATA_LINK_ETH, "Ethernet"},
  {0,                                                     NULL     }
};

static const value_string vspec_tag_dslf_access_loop_encap_encap_1_vals[] = {
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_NA,                "NA"                    },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_UNTAGGED_ETH,      "Untagged Ethernet"     },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_SINGLE_TAGGED_ETH, "Single-tagged Ethernet"},
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_1_DOUBLE_TAGGED_ETH, "Double-tagged Ethernet"},
  {0,                                                     NULL                                }
};

static const value_string vspec_tag_dslf_access_loop_encap_encap_2_vals[] = {
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_NA,                            "NA"                             },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_PPPOA_LLC,                     "PPPoA LLC"                      },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_PPPOA_NULL,                    "PPPoA Null"                     },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_IPOA_LLC,                      "IPoA LLC"                       },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_IPOA_NULL,                     "IPoA Null"                      },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_LLC_WITH_FCS,    "Ethernet over AAL5 LLC w FCS"   },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_LLC_WITHOUT_FCS, "Ethernet over AAL5 LLC w/o FCS" },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_NULL_WITH_FCS,   "Ethernet over AAL5 Null w FCS"  },
  {PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAP_ENCAPS_2_ETH_OVER_AAL5_NULL_WITHOUT_FCS,"Ethernet over AAL5 Null w/o FCS"},
  {0,                                                     NULL                               }
};

static const value_string datarate_scale_vals[] = {
  {PPPOE_SCALE_KBPS,  "kilobits per second"},
  {PPPOE_SCALE_MBPS,  "megabits per second"},
  {PPPOE_SCALE_GBPS,  "gigabits per second"},
  {PPPOE_SCALE_TBPS,  "terabits per second"},
  {0,     NULL         }
};


#define CASE_VSPEC_DSLF_TAG_UINT(tag_name, relation, length, hf_var) case tag_name: \
    if (!(poe_tag_length relation length)) { \
      expert_add_info_format(pinfo, pppoe_tree, &ei_pppoe_tag_length, \
      "%s: Wrong length: %u (expected %s %d)", \
      val_to_str_const(poe_tag, vspec_tag_vals, "Unknown"), poe_tag_length, #relation, length); \
    } else { \
      proto_tree_add_item(pppoe_tree, hf_var, tvb, \
        tagstart+2, poe_tag_length, ENC_BIG_ENDIAN); \
    } \
  break;

#define CASE_VSPEC_DSLF_TAG_STRING(tag_name, relation, length, hf_var) case tag_name: \
    if (!(poe_tag_length relation length)) { \
      expert_add_info_format(pinfo, pppoe_tree, &ei_pppoe_tag_length, \
      "%s: Wrong length: %u (expected %s %d)", \
      val_to_str_const(poe_tag, vspec_tag_vals, "Unknown"), poe_tag_length, #relation, length); \
    } else { \
      proto_tree_add_item(pppoe_tree, hf_var, tvb, \
        tagstart+2, poe_tag_length, ENC_ASCII|ENC_NA); \
    } \
  break;

/* Dissect Vendor-Specific Tags introduced by the DSLF */
static void
dissect_pppoe_subtags_dslf(tvbuff_t *tvb, packet_info *pinfo _U_, int offset, proto_tree *tree,
         int payload_length)
{
  uint8_t poe_tag;
  uint8_t poe_tag_length;
  int tagstart;

  proto_tree  *pppoe_tree, *ti, *encaps_tree;

  /* Start Decoding Here. */
  /* Create tags subtree */
  ti = proto_tree_add_item(tree, hf_pppoed_tag_vspec_tags, tvb, offset, payload_length, ENC_NA);
  pppoe_tree = proto_item_add_subtree(ti, ett_pppoed_tags);

  tagstart = offset;

  /* Loop until all data seen or End-Of-List tag found */
  while (tagstart <= offset + payload_length-2)
  {
    poe_tag = tvb_get_uint8(tvb, tagstart);
    poe_tag_length = tvb_get_uint8(tvb, tagstart + 1);

    /* Tag value and data length */
    if (global_pppoe_show_tags_and_lengths)
    {
      proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vspec_tag, tvb, tagstart, 1, ENC_BIG_ENDIAN);
      proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length_8, tvb, tagstart+1, 1, ENC_BIG_ENDIAN);
    }

    /* Show tag data */
    switch (poe_tag)
    {
      CASE_VSPEC_DSLF_TAG_STRING(PPPOE_TAG_VSPEC_DSLF_CIRCUIT_ID, <=, 63,
          hf_pppoed_tag_vspec_circuit_id)
      CASE_VSPEC_DSLF_TAG_STRING(PPPOE_TAG_VSPEC_DSLF_REMOTE_ID, <=, 63,
          hf_pppoed_tag_vspec_remote_id)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_ACT_DATA_RATE_UP, ==, 4,
          hf_pppoed_tag_vspec_act_data_rate_up)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_ACT_DATA_RATE_DOWN, ==, 4,
          hf_pppoed_tag_vspec_act_data_rate_down)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_UP, ==, 4,
          hf_pppoed_tag_vspec_min_data_rate_up)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_DOWN, ==, 4,
          hf_pppoed_tag_vspec_min_data_rate_down)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_ATTAINABLE_DATA_RATE_UP, ==, 4,
          hf_pppoed_tag_vspec_attainable_data_rate_up)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_ATTAINABLE_DATA_RATE_DOWN, ==, 4,
          hf_pppoed_tag_vspec_attainable_data_rate_down)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MAX_DATA_RATE_UP, ==, 4,
          hf_pppoed_tag_vspec_max_data_rate_up)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MAX_DATA_RATE_DOWN, ==, 4,
          hf_pppoed_tag_vspec_max_data_rate_down)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_UP_LP, ==, 4,
          hf_pppoed_tag_vspec_min_data_rate_up_lp)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MIN_DATA_RATE_DOWN_LP, ==, 4,
          hf_pppoed_tag_vspec_min_data_rate_down_lp)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MAX_INT_DELAY_UP, ==, 4,
          hf_pppoed_tag_vspec_max_int_delay_up)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_ACT_INT_DELAY_UP, ==, 4,
          hf_pppoed_tag_vspec_act_int_delay_up)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_MAX_INT_DELAY_DOWN, ==, 4,
          hf_pppoed_tag_vspec_max_int_delay_down)
      CASE_VSPEC_DSLF_TAG_UINT(PPPOE_TAG_VSPEC_DSLF_ACT_INT_DELAY_DOWN, ==, 4,
          hf_pppoed_tag_vspec_act_int_delay_down)
      case PPPOE_TAG_VSPEC_DSLF_ACCESS_LOOP_ENCAPSULATION:
        ti = proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vspec_access_loop_encapsulation, tvb,
            tagstart+2, 3, ENC_NA);
        if (poe_tag_length != 3) {
          expert_add_info_format(pinfo, ti, &ei_pppoe_tag_length, "%s: Wrong length: %u (expected 3)", val_to_str_const(poe_tag, vspec_tag_vals, "Unknown"), poe_tag_length);
        }
        encaps_tree = proto_item_add_subtree(ti, ett_pppoed_tag_vspec_dslf_access_loop_encaps);
        proto_tree_add_item(encaps_tree, hf_pppoed_tag_vspec_access_loop_encap_data_link,
            tvb, tagstart+2, 1, ENC_BIG_ENDIAN);
        proto_tree_add_item(encaps_tree, hf_pppoed_tag_vspec_access_loop_encap_encap_1,
            tvb, tagstart+3, 1, ENC_BIG_ENDIAN);
        proto_tree_add_item(encaps_tree, hf_pppoed_tag_vspec_access_loop_encap_encap_2,
            tvb, tagstart+4, 1, ENC_BIG_ENDIAN);

        break;
      default:
        if (poe_tag_length > 0 )
        {
          /* Presumably unknown tag;
             show tag value if we didn't do it above */
          if (!global_pppoe_show_tags_and_lengths)
          {
            proto_tree_add_item(pppoe_tree, hf_pppoed_tag, tvb, tagstart, 1, ENC_BIG_ENDIAN);
            proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length_8, tvb, tagstart+1, 1, ENC_BIG_ENDIAN);
          }
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_unknown_data, tvb,
              tagstart+2, poe_tag_length, ENC_NA);
        }
    }

    tagstart += (2 + poe_tag_length);
  }
}


/* Dissect discovery protocol tags */
static void
dissect_pppoe_tags(tvbuff_t *tvb, packet_info *pinfo, int offset, proto_tree *tree,
       int payload_length)
{
  uint16_t poe_tag;
  uint16_t poe_tag_length;
  int tagstart;
  uint16_t poe_rsv = 0;

  proto_tree  *pppoe_tree;
  proto_item  *ti;
  proto_item  *pppoe_tree_tag_length_item = NULL;

  /* Start Decoding Here. */
  /* Create tags subtree */
  ti = proto_tree_add_item(tree, hf_pppoed_tags, tvb, offset, payload_length-6, ENC_NA);
  pppoe_tree = proto_item_add_subtree(ti, ett_pppoed_tags);

  tagstart = offset;

  /* Loop until all data seen or End-Of-List tag found */
  while (tagstart <= payload_length-2)
  {
    poe_tag = tvb_get_ntohs(tvb, tagstart);
    poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2);

    /* Tag value and data length */
    if (global_pppoe_show_tags_and_lengths)
    {
      proto_tree_add_item(pppoe_tree, hf_pppoed_tag, tvb, tagstart, 2, ENC_BIG_ENDIAN);
      pppoe_tree_tag_length_item =
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length, tvb, tagstart+2, 2, ENC_BIG_ENDIAN);
    }

    /* Show tag data */
    switch (poe_tag)
    {
      case PPPOE_TAG_SVC_NAME:
        if (poe_tag_length > 0)
        {
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_service_name, tvb,
                  tagstart+4, poe_tag_length, ENC_ASCII);
        }
        break;
      case PPPOE_TAG_AC_NAME:
        {
        const uint8_t* str;
        proto_tree_add_item_ret_string(pppoe_tree, hf_pppoed_tag_ac_name, tvb,
                tagstart+4, poe_tag_length, ENC_ASCII|ENC_NA, pinfo->pool, &str);
        /* Show AC-Name in info column */
        col_append_fstr(pinfo->cinfo, COL_INFO, " AC-Name='%s'", str);
        }
        break;
      case PPPOE_TAG_HOST_UNIQ:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_host_uniq, tvb,
                tagstart+4, poe_tag_length, ENC_NA);
        break;
      case PPPOE_TAG_AC_COOKIE:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_cookie, tvb,
                tagstart+4, poe_tag_length, ENC_NA);
        break;
      case PPPOE_TAG_VENDOR:
        if (poe_tag_length >= 4)
        {
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vendor_id, tvb,
                    tagstart+4, 4, ENC_BIG_ENDIAN);
        }
        if (poe_tag_length > 4)
        {
          uint32_t vendor_id = tvb_get_ntohl(tvb, tagstart+4);
          switch (vendor_id)
          {
            case PPPOE_VENDOR_ID_DSLF:
              dissect_pppoe_subtags_dslf(tvb,pinfo,tagstart+4+4,pppoe_tree,poe_tag_length-4);
              break;
            default:
              proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vendor_unspecified, tvb,
                      tagstart+4+4, poe_tag_length-4, ENC_NA);

          }
        }
        break;
      case PPPOE_TAG_CREDITS:
        if (poe_tag_length == 4)
        {
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits_fcn, tvb,
                  tagstart+4, 2, ENC_BIG_ENDIAN);
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits_bcn, tvb,
                  tagstart+6, 2, ENC_BIG_ENDIAN);
        } else {
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits, tvb,
                  tagstart+4, poe_tag_length, ENC_NA);
        }
        break;
      case PPPOE_TAG_METRICS:
        if (poe_tag_length == 10)
        {
          poe_rsv = tvb_get_ntohs(tvb, tagstart+4);

          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_mdr_units, tvb,
                  tagstart+4, 2, ENC_BIG_ENDIAN);
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_cdr_units, tvb,
                  tagstart+4, 2, ENC_BIG_ENDIAN);
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_r, tvb,
                  tagstart+4, 2, ENC_BIG_ENDIAN);
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_rlq, tvb,
                  tagstart+6, 1, ENC_BIG_ENDIAN);
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_resource, tvb,
                  tagstart+7, 1, ENC_BIG_ENDIAN);
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_latency, tvb,
                  tagstart+8, 2, ENC_BIG_ENDIAN);

          /* CDR */
          ti = proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_curr_drate, tvb,
                 tagstart+10, 2, ENC_BIG_ENDIAN);

          switch ((poe_rsv & PPPOE_CDR_MASK) >> 1)
          {
            case (PPPOE_SCALE_KBPS):
              proto_item_append_text(ti, " kbps");
              break;
            case (PPPOE_SCALE_MBPS):
              proto_item_append_text(ti, " mbps");
              break;
            case (PPPOE_SCALE_GBPS):
              proto_item_append_text(ti, " gbps");
              break;
            case (PPPOE_SCALE_TBPS):
              proto_item_append_text(ti, " tbps");
              break;
          }

          /* MDR */
          ti = proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_max_drate, tvb,
                  tagstart+12, 2, ENC_BIG_ENDIAN);

          switch ((poe_rsv & PPPOE_MDR_MASK) >> 3)
          {
            case (PPPOE_SCALE_KBPS):
              proto_item_append_text(ti, " kbps");
              break;
            case (PPPOE_SCALE_MBPS):
              proto_item_append_text(ti, " mbps");
              break;
            case (PPPOE_SCALE_GBPS):
              proto_item_append_text(ti, " gbps");
              break;
            case (PPPOE_SCALE_TBPS):
              proto_item_append_text(ti, " tbps");
              break;
          }

        } else {
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics, tvb,
                  tagstart+4, poe_tag_length, ENC_NA);
        }
        break;
      case PPPOE_TAG_SEQ_NUM:
        if (poe_tag_length == 2) {
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_seq_num, tvb,
                  tagstart+4, poe_tag_length, ENC_BIG_ENDIAN);
        } else {
          if (global_pppoe_show_tags_and_lengths) {
            proto_item_append_text(pppoe_tree_tag_length_item, " [Wrong: should be 2]");
          }

          proto_tree_add_expert_format(pppoe_tree, pinfo, &ei_pppoe_tag_length, tvb, tagstart+4, poe_tag_length,
                "Sequence Number tag: Wrong length: %u (expected 2)", poe_tag_length);
        }
        break;
      case PPPOE_TAG_CRED_SCALE:
        if (poe_tag_length == 2) {
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_cred_scale, tvb,
                  tagstart+4, poe_tag_length, ENC_BIG_ENDIAN);
        } else {
          if (global_pppoe_show_tags_and_lengths) {
            proto_item_append_text(pppoe_tree_tag_length_item, " [Wrong: should be 2]");
          }
          proto_tree_add_expert_format(pppoe_tree, pinfo, &ei_pppoe_tag_length, tvb, tagstart+4, poe_tag_length,
                "Credit Scale Factor tag: Wrong length: %u (expected 2)", poe_tag_length);
        }
        break;
      case PPPOE_TAG_RELAY_ID:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_relay_session_id, tvb,
                tagstart+4, poe_tag_length, ENC_NA);
        break;
      case PPPOE_TAG_HURL:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_hurl, tvb,
                tagstart+4, poe_tag_length, ENC_NA);
        break;
      case PPPOE_TAG_MOTM:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_motm, tvb,
                tagstart+4, poe_tag_length, ENC_NA);
        break;
      case PPPOE_TAG_MAX_PAYLD:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_max_payload, tvb,
                tagstart+4, poe_tag_length, ENC_NA);
        break;
      case PPPOE_TAG_IP_RT_ADD:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ip_route_add, tvb,
                tagstart+4, poe_tag_length, ENC_NA);
        break;

      /* These error tag values should be interpreted as a utf-8 unterminated
         strings. */
      case PPPOE_TAG_SVC_ERR:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_service_name_error, tvb,
                tagstart+4, poe_tag_length, ENC_ASCII);
        break;
      case PPPOE_TAG_AC_ERR:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_system_error, tvb,
                tagstart+4, poe_tag_length, ENC_ASCII);
        break;
      case PPPOE_TAG_GENERIC_ERR:
        proto_tree_add_item(pppoe_tree, hf_pppoed_tag_generic_error, tvb,
                tagstart+4, poe_tag_length, ENC_ASCII);
        break;

      /* Get out if see end-of-list tag */
      case PPPOE_TAG_EOL:
        return;

      default:
        if (poe_tag_length > 0 )
        {
          /* Presumably unknown tag;
             show tag value if we didn't
             do it above */
          if (!global_pppoe_show_tags_and_lengths)
          {
            proto_tree_add_item(pppoe_tree, hf_pppoed_tag, tvb, tagstart, 2, ENC_BIG_ENDIAN);
            proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length, tvb, tagstart+2, 2, ENC_BIG_ENDIAN);
          }
          proto_tree_add_item(pppoe_tree, hf_pppoed_tag_unknown_data, tvb,
              tagstart+2, poe_tag_length, ENC_NA);
        }
    }

    tagstart += (4 + poe_tag_length);
  }
}


/* Discovery protocol, i.e. PPP session not yet established */
static int dissect_pppoed(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
  uint8_t pppoe_code;
  uint16_t reported_payload_length;

  proto_tree  *pppoe_tree = NULL;
  proto_item  *ti;

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

  /* Start Decoding Here. */
  pppoe_code = tvb_get_uint8(tvb, 1);

  col_append_str(pinfo->cinfo, COL_INFO, val_to_str_const(pppoe_code, code_vals, "Unknown"));

  /* Read length of payload */
  reported_payload_length = tvb_get_ntohs(tvb, 4);

  if (tree)
  {
    ti = proto_tree_add_item(tree, proto_pppoed, tvb, 0, reported_payload_length+6, ENC_NA);
    pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);

    /* Dissect fixed fields */
    proto_tree_add_item(pppoe_tree, hf_pppoe_version, tvb, 0, 1, ENC_BIG_ENDIAN);
    proto_tree_add_item(pppoe_tree, hf_pppoe_type, tvb, 0, 1, ENC_BIG_ENDIAN);
    proto_tree_add_item(pppoe_tree, hf_pppoe_code, tvb, 1, 1, ENC_BIG_ENDIAN);
    proto_tree_add_item(pppoe_tree, hf_pppoe_session_id, tvb, 2, 2, ENC_BIG_ENDIAN);
    proto_tree_add_item(pppoe_tree, hf_pppoe_payload_length, tvb, 4, 2, ENC_BIG_ENDIAN);
  }

  /* Now dissect any tags */
  if (reported_payload_length > 0)
  {
    dissect_pppoe_tags(tvb, pinfo, 6, pppoe_tree, 6+reported_payload_length);
  }

  return tvb_captured_length(tvb);
}

void proto_register_pppoed(void)
{
  static hf_register_info hf[] =
  {
    /* Discovery tag fields */
    { &hf_pppoed_tags,
      { "PPPoE Tags", "pppoed.tags", FT_NONE, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag,
      { "Tag", "pppoed.tag", FT_UINT16, BASE_HEX,
         VALS(tag_vals), 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_length,
      { "Tag Length", "pppoed.tag_length", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_length_8,
      { "Tag Length", "pppoed.tag_length_8", FT_UINT8, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_unknown_data,
      { "Unknown Data", "pppoed.tag.unknown_data", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_service_name,
      { "Service-Name", "pppoed.tags.service_name", FT_STRING, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_ac_name,
      { "AC-Name", "pppoed.tags.ac_name", FT_STRING, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_host_uniq,
      { "Host-Uniq", "pppoed.tags.host_uniq", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_ac_cookie,
      { "AC-Cookie", "pppoed.tags.ac_cookie", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_vendor_id,
      { "Vendor id", "pppoed.tags.vendor_id", FT_UINT32, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_vendor_unspecified,
      { "Vendor unspecified", "pppoed.tags.vendor_unspecified", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_vspec_tags,
      { "Vendor Specific PPPoE Tags", "pppoed.tags.vendorspecific.tags", FT_NONE, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_vspec_tag,
      { "Tag", "pppoed.tags.vendorspecific.tag", FT_UINT8, BASE_HEX,
         VALS(vspec_tag_vals), 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_vspec_circuit_id,
            { "Circuit ID", "pppoed.tags.circuit_id", FT_STRING, BASE_NONE,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_remote_id,
            { "Remote ID", "pppoed.tags.remote_id", FT_STRING, BASE_NONE,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_act_data_rate_up,
            { "Actual Data Rate Upstream", "pppoed.tags.act_data_rate_up", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_act_data_rate_down,
            { "Actual Data Rate Downstream", "pppoed.tags.act_data_rate_down", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_min_data_rate_up,
            { "Minimum Data Rate Upstream", "pppoed.tags.min_data_rate_up", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_min_data_rate_down,
            { "Minimum Data Rate Downstream", "pppoed.tags.min_data_rate_down", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_attainable_data_rate_up,
            { "Attainable DataRate Upstream", "pppoed.tags.attainable_data_rate_up", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_attainable_data_rate_down,
            { "Attainable DataRate Downstream", "pppoed.tags.attainable_data_rate_down", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_max_data_rate_up,
            { "Maximum Data Rate Upstream", "pppoed.tags.max_data_rate_up", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_max_data_rate_down,
            { "Maximum Data Rate Downstream", "pppoed.tags.max_data_rate_down", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_min_data_rate_up_lp,
            { "Min DataRate Upstream in low power state", "pppoed.tags.min_data_rate_up_lp", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_min_data_rate_down_lp,
            { "Minimum Data Rate Downstream in low power state", "pppoed.tags.min_data_rate_down_lp", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_max_int_delay_up,
            { "Max Interleaving Delay Upstream", "pppoed.tags.max_int_delay_up", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_act_int_delay_up,
            { "Actual Interleaving Delay Upstream", "pppoed.tags.act_int_delay_up", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_max_int_delay_down,
            { "Maximum Interleaving Delay Downstream", "pppoed.tags.max_int_delay_down", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_act_int_delay_down,
            { "Actual Interleaving Delay Downstream", "pppoed.tags.act_int_delay_down", FT_UINT32, BASE_DEC,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_access_loop_encapsulation,
            { "Access-Loop-Encapsulation", "pppoed.tags.access_loop_encap", FT_NONE, BASE_NONE,
                     NULL, 0x0, NULL, HFILL
            }
    },
    { &hf_pppoed_tag_vspec_access_loop_encap_data_link,
      { "Data link", "pppoed.tags.access_loop_encap.data_link", FT_UINT8, BASE_HEX,
         VALS(vspec_tag_dslf_access_loop_encap_data_link_vals), 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_vspec_access_loop_encap_encap_1,
      { "Encaps 1", "pppoed.tags.access_loop_encap.encap_1", FT_UINT8, BASE_HEX,
         VALS(vspec_tag_dslf_access_loop_encap_encap_1_vals), 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_vspec_access_loop_encap_encap_2,
      { "Encaps 2", "pppoed.tags.access_loop_encap.encap_2", FT_UINT8, BASE_HEX,
         VALS(vspec_tag_dslf_access_loop_encap_encap_2_vals), 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_credits,
      { "Credits", "pppoed.tags.credits", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_credits_fcn,
      { "FCN", "pppoed.tags.credits.fcn", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_credits_bcn,
      { "BCN", "pppoed.tags.credits.bcn", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_metrics,
      { "Metrics", "pppoed.tags.metrics", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_metrics_r,
      { "Receive Only", "pppoed.tags.metrics.r", FT_BOOLEAN, 16,
         NULL, PPPOE_RCV_ONLY_MASK, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_mdr_units,
      { "MDR Units", "pppoed.tags.metrics.mdr_units", FT_UINT16, BASE_HEX,
         VALS(datarate_scale_vals), PPPOE_MDR_MASK, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_cdr_units,
      { "CDR Units", "pppoed.tags.metrics.cdr_units", FT_UINT16, BASE_HEX,
         VALS(datarate_scale_vals), PPPOE_CDR_MASK, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_metrics_rlq,
      { "Relative Link Quality", "pppoed.tags.metrics.rlq", FT_UINT8, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_metrics_resource,
      { "Resource", "pppoed.tags.metrics.resource", FT_UINT8, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_metrics_latency,
      { "Latency", "pppoed.tags.metrics.latency", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_metrics_curr_drate,
      { "Curr. datarate", "pppoed.tags.metrics.curr_drate", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_metrics_max_drate,
      { "Max. datarate", "pppoed.tags.metrics.max_drate", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_seq_num,
      { "Sequence Number", "pppoed.tags.seq_num", FT_UINT16, BASE_HEX,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_cred_scale,
      { "Credit Scale Factor", "pppoed.tags.credit_scale", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_relay_session_id,
      { "Relay-Session-Id", "pppoed.tags.relay_session_id", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_hurl,
      { "HURL", "pppoed.tags.hurl", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_motm,
      { "MOTM", "pppoed.tags.motm", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_max_payload,
      { "PPP-Max-Payload", "pppoed.tags.max_payload", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_ip_route_add,
      { "IP Route Add", "pppoed.tags.ip_route_add", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_service_name_error,
      { "Service-Name-Error", "pppoed.tags.service_name_error", FT_STRING, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_ac_system_error,
      { "AC-System-Error", "pppoed.tags.ac_system_error", FT_STRING, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoed_tag_generic_error,
      { "Generic-Error", "pppoed.tags.generic_error", FT_STRING, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    }
  };

  static int *ett[] = {
    &ett_pppoed,
    &ett_pppoed_tags,
    &ett_pppoed_tag_vspec_dslf_access_loop_encaps
  };

  module_t *pppoed_module;

  /* Register protocol and fields */
  proto_pppoed = proto_register_protocol("PPP-over-Ethernet Discovery",
                                         "PPPoED", "pppoed");
  proto_register_subtree_array(ett, array_length(ett));
  proto_register_field_array(proto_pppoed, hf, array_length(hf));

  /* Register dissector handle */
  pppoed_handle = register_dissector("pppoed", dissect_pppoed, proto_pppoed);

  /* Preference setting */
  pppoed_module = prefs_register_protocol(proto_pppoed, NULL);
  prefs_register_bool_preference(pppoed_module, "show_tags_and_lengths",
                                 "Show tag values and lengths",
                                 "Show values of tags and lengths of data fields",
                                 &global_pppoe_show_tags_and_lengths);
}

void proto_reg_handoff_pppoed(void)
{
  dissector_add_uint("ethertype", ETHERTYPE_PPPOED, pppoed_handle);
}


/* Session protocol, i.e. PPP session established */
static int dissect_pppoes(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
  uint8_t pppoe_code;
  uint16_t reported_payload_length;
  uint16_t poe_tag_length;
  int     actual_payload_length;
  int     length, reported_length;
  int     credit_offset = 0, tagstart = 0;
  uint16_t cp_code;

  proto_tree  *pppoe_tree;
  proto_item  *ti = NULL;
  tvbuff_t    *next_tvb;

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

  /* Start Decoding Here. */
  pppoe_code = tvb_get_uint8(tvb, 1);

  col_set_str(pinfo->cinfo, COL_INFO,
                 val_to_str_const(pppoe_code, code_vals, "Unknown"));

  reported_payload_length = tvb_get_ntohs(tvb, 4);
  actual_payload_length = tvb_reported_length_remaining(tvb, 6);

  ti = proto_tree_add_item(tree, proto_pppoes, tvb, 0, 6, ENC_NA);
  pppoe_tree = proto_item_add_subtree(ti, ett_pppoe);

  proto_tree_add_item(pppoe_tree, hf_pppoe_version, tvb, 0, 1, ENC_BIG_ENDIAN);
  proto_tree_add_item(pppoe_tree, hf_pppoe_type, tvb, 0, 1, ENC_BIG_ENDIAN);
  proto_tree_add_item(pppoe_tree, hf_pppoe_code, tvb, 1, 1, ENC_BIG_ENDIAN);
  proto_tree_add_item(pppoe_tree, hf_pppoe_session_id, tvb, 2, 2, ENC_BIG_ENDIAN);
  ti = proto_tree_add_item(pppoe_tree, hf_pppoe_payload_length, tvb, 4, 2, ENC_BIG_ENDIAN);


  if (PPPOE_TAG_CREDITS == tvb_get_ntohs(tvb, 6))
  {
    tagstart = 6;
    poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2);

    /* Create tags subtree */
    ti = proto_tree_add_item(pppoe_tree, hf_pppoes_tags, tvb, tagstart, 8, ENC_NA);
    pppoe_tree = proto_item_add_subtree(ti, ett_pppoes_tags);

    /* Show tag data */
    if (poe_tag_length == 4)
    {
      proto_tree_add_item(pppoe_tree, hf_pppoes_tag_credits_fcn, tvb,
        tagstart+4, 2, ENC_BIG_ENDIAN);
      proto_tree_add_item(pppoe_tree, hf_pppoes_tag_credits_bcn, tvb,
        tagstart+6, 2, ENC_BIG_ENDIAN);
    } else {
      proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits, tvb,
        tagstart+4, poe_tag_length, ENC_NA);
    }

    credit_offset = 8;
  }

  /*
   * The only reason why the payload length from the header
   * should differ from the remaining data in the packet
   * would be if the total packet length, including Ethernet
   * CRC, were < 64 bytes, so that padding was required.
   *
   * That means that you have 14 bytes of Ethernet header,
   * 4 bytes of FCS, and fewer than 46 bytes of PPPoE packet.
   *
   * If that's not the case, we report a difference between
   * the payload length in the packet, and the amount of
   * data following the PPPoE header, as an error.
   */
  if (tvb_reported_length(tvb) > 46) {
    /*
     * Be forgiving about a possible trailing FCS.
     *
     * XXX - this dissector currently doesn't know
     * whether any extra data past the end of the PPP
     * payload is an FCS or not.
     *
     * If we know that we have an FCS, or that we don't
     * have an FCS, we should have been handed a tvbuff
     * without the FCS, and we should just do the strict
     * length check.
     *
     * If we don't know whether we have an FCS, then:
     *
     *   if this isn't over Ethernet - the "E" in "PPPoE"
     *   nonwithstanding, it can also run on top of 802.11,
     *   for example - there's no trailer, so any data
     *   past the payload length is either an FCS or
     *   bogus;
     *
     *   if this is over Ethernet, there shouldn't be
     *   a trailer, as the packet is long enough not to
     *   require a trailer, as per the above;
     *
     * so perhaps we should assume that if we have exactly
     * 4 bytes of extra information, it's an FCS, otherwise
     * it's not.
     *
     * Perhaps we need to have a routine to call to
     * do all the length checking, etc., and call it
     * from here and from other dissectors where the
     * protocol has a length field, or have a way to
     * tell the dissector that called us which field
     * has the length field and have *that* dissector
     * do the length checking and add the expert info
     * to the length field, *after* it does all the
     * FCS heuristics.
     */

    /* retrieve the control protocol code if it's there */
    cp_code = tvb_get_ntohs(tvb, 6);
    /*
     * The session payload length expressly does not include pad bytes
     * when LCP or IPCP or IPv6CP are present, so avoid the spurious error message
     */
    if ((cp_code != PPP_LCP) && (cp_code != PPP_IPCP) && (cp_code != PPP_IPV6CP) &&
      (reported_payload_length != actual_payload_length) &&
      ((reported_payload_length + 4) != actual_payload_length)) {
      proto_item_append_text(ti, " [incorrect, should be %u]",
        actual_payload_length);
      expert_add_info_format(pinfo, ti, &ei_pppoe_payload_length, "Possible bad payload length %u != %u", reported_payload_length, actual_payload_length);
    }
  }

  /*
   * Construct a tvbuff containing the PPP packet.
   */
  length = tvb_captured_length_remaining(tvb, 6);
  reported_length = tvb_reported_length_remaining(tvb, 6);
  DISSECTOR_ASSERT(length >= 0);
  DISSECTOR_ASSERT(reported_length >= 0);
  if (length > reported_length)
    length = reported_length;
  if ((unsigned)length > reported_payload_length)
    length = reported_payload_length;
  if ((unsigned)reported_length > reported_payload_length)
    reported_length = reported_payload_length;
  next_tvb = tvb_new_subset_length_caplen(tvb,(6 + credit_offset),
        (length - credit_offset),
        (reported_length - credit_offset));
  call_dissector(ppp_handle,next_tvb,pinfo,tree);
  return tvb_captured_length(tvb);
}

void proto_register_pppoes(void)
{

  static hf_register_info hf[] =
  {
    { &hf_pppoes_tags,
      { "PPPoE Tags", "pppoes.tags", FT_NONE, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
#if 0
    { &hf_pppoes_tag,
      { "Tag", "pppoes.tag", FT_UINT16, BASE_HEX,
         VALS(tag_vals), 0x0, NULL, HFILL
      }
    },
#endif
#if 0
    { &hf_pppoes_tag_credits,
      { "Credits", "pppoes.tags.credits", FT_BYTES, BASE_NONE,
         NULL, 0x0, NULL, HFILL
      }
    },
#endif
    { &hf_pppoes_tag_credits_fcn,
      { "FCN", "pppoes.tags.credits.fcn", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoes_tag_credits_bcn,
      { "BCN", "pppoes.tags.credits.bcn", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    }
  };

  static int *ett[] = {
    &ett_pppoes,
    &ett_pppoes_tags
  };

  /* Register protocol */
  proto_pppoes = proto_register_protocol("PPP-over-Ethernet Session", "PPPoES", "pppoes");

  proto_register_subtree_array(ett, array_length(ett));
  proto_register_field_array(proto_pppoes, hf, array_length(hf));

  pppoes_handle = register_dissector("pppoes", dissect_pppoes, proto_pppoes);
}

void proto_register_pppoe(void)
{
  static hf_register_info hf[] =
  {
    /* These fields common to discovery and session protocols */
    { &hf_pppoe_version,
      { "Version", "pppoe.version", FT_UINT8, BASE_DEC,
         NULL, 0xf0, NULL, HFILL
      }
    },
    { &hf_pppoe_type,
      { "Type", "pppoe.type", FT_UINT8, BASE_DEC,
         NULL, 0x0f, NULL, HFILL
      }
    },
    { &hf_pppoe_code,
      { "Code", "pppoe.code", FT_UINT8, BASE_HEX,
         VALS(code_vals), 0x0, NULL, HFILL
      }
    },
    { &hf_pppoe_session_id,
      { "Session ID", "pppoe.session_id", FT_UINT16, BASE_HEX,
         NULL, 0x0, NULL, HFILL
      }
    },
    { &hf_pppoe_payload_length,
      { "Payload Length", "pppoe.payload_length", FT_UINT16, BASE_DEC,
         NULL, 0x0, NULL, HFILL
      }
    }
  };

  static int *ett[] = {
    &ett_pppoe
  };

  static ei_register_info ei[] = {
    { &ei_pppoe_tag_length, { "pppoed.tag_length.invalid", PI_MALFORMED, PI_WARN, "Wrong length", EXPFILL }},
    { &ei_pppoe_payload_length, { "pppoe.payload_length.bad", PI_MALFORMED, PI_WARN, "Possible bad payload length", EXPFILL }},
  };

  expert_module_t* expert_pppoe;

  /* Register protocol */
  proto_pppoe = proto_register_protocol("PPP-over-Ethernet", "PPPoE", "pppoe");

  proto_register_subtree_array(ett, array_length(ett));
  proto_register_field_array(proto_pppoe, hf, array_length(hf));
  expert_pppoe = expert_register_protocol(proto_pppoe);
  expert_register_field_array(expert_pppoe, ei, array_length(ei));

}

void proto_reg_handoff_pppoes(void)
{
  dissector_add_uint("ethertype", ETHERTYPE_PPPOES, pppoes_handle);
  dissector_add_uint("wtap_encap", WTAP_ENCAP_PPP_ETHER, pppoes_handle);

  /* Get a handle for the PPP dissector */
  ppp_handle = find_dissector_add_dependency("ppp", proto_pppoes);
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */

Coverage Report

Created: 2025-12-27 06:52