epan/dissectors/packet-auto_rp.c

   1 /* packet-auto_rp.c
   2  * Routines for the Cisco Auto-RP protocol
   3  * ftp://ftpeng.cisco.com/ftp/ipmulticast/specs/pim-autorp-spec01.txt
   4  *
   5  * Heikki Vatiainen <hessu@cs.tut.fi>
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * SPDX-License-Identifier: GPL-2.0-or-later
  12  */
  13
  14 #include "config.h"
  15
  16 #include <epan/packet.h>
  17 #include <epan/to_str.h>
  18
  19 #include <wsutil/str_util.h>
  20
  21 void proto_register_auto_rp(void);
  22 void proto_reg_handoff_auto_rp(void);
  23
  24 static dissector_handle_t auto_rp_handle;
  25
  26 static int proto_auto_rp;
  27 static int ett_auto_rp;
  28 static int ett_auto_rp_ver_type;
  29 static int ett_auto_rp_map;
  30 static int ett_auto_rp_group;
  31
  32 static int hf_auto_rp_version;
  33 static int hf_auto_rp_type;
  34 static int hf_auto_rp_count;
  35 static int hf_auto_rp_holdtime;
  36 static int hf_auto_rp_pim_ver;
  37 static int hf_auto_rp_rp_addr;
  38 static int hf_auto_rp_prefix_sgn;
  39 static int hf_auto_rp_mask_len;
  40 static int hf_auto_rp_group_prefix;
  41 static int hf_auto_rp_reserved;
  42 static int hf_auto_rp_trailing_junk;
  43 static int hf_auto_rp_group_num;
  44
  45 #define UDP_PORT_PIM_RP_DISC 496
  46
  47 struct auto_rp_fixed_hdr {
  48 #define AUTO_RP_VERSION_MASK 0xf0
  49 #define AUTO_RP_TYPE_MASK    0x0f
  50         uint8_t ver_type;       /* pim-autorp-spec01.txt defines version 1+ */
  51         uint8_t rp_count;       /* Number of struct auto_rp_maps that follow the this header */
  52         uint16_t holdtime;       /* Time in seconds this announcement is valid. 0 equals forever */
  53         uint32_t reserved;
  54 };
  55
  56 struct auto_rp_map_hdr {
  57         uint32_t rp_address;       /* The unicast IPv4 address of this RP */
  58 #define AUTO_RP_PIM_VER_MASK 0x03
  59         uint8_t pim_version;      /* RP's highest PIM version. 2-bit field */
  60         uint8_t group_count;      /* Number of encoded group addresses that follow this header */
  61 };
  62
  63 struct auto_rp_enc_grp_hdr {   /* Encoded group address */
  64 #define AUTO_RP_SIGN_MASK 0x01
  65         uint8_t prefix_sgn;    /* 0 positive, 1 negative group prefix */
  66         uint8_t mask_len;      /* Length of group prefix */
  67         uint32_t addr;          /* Group prefix */
  68 };
  69
  70 #define AUTO_RP_VER_1PLUS 1
  71 static const value_string auto_rp_ver_vals[] = {
  72         {AUTO_RP_VER_1PLUS, "1 or 1+"},
  73         {0,                 NULL}
  74 };
  75
  76 #define AUTO_RP_TYPE_ANNOUNCEMENT 1
  77 #define AUTO_RP_TYPE_MAPPING      2
  78 static const value_string auto_rp_type_vals[] = {
  79         {AUTO_RP_TYPE_ANNOUNCEMENT, "RP announcement"},
  80         {AUTO_RP_TYPE_MAPPING,      "RP mapping"},
  81         {0,                         NULL}
  82 };
  83
  84 #define AUTO_RP_PIM_VERSION_UNKNOWN 0x00
  85 #define AUTO_RP_PIM_VERSION_1       0x01
  86 #define AUTO_RP_PIM_VERSION_2       0x02
  87 #define AUTO_RP_PIM_VERSION_DUAL    0x03
  88 static const value_string auto_rp_pim_ver_vals[] = {
  89         {AUTO_RP_PIM_VERSION_UNKNOWN, "Version unknown"},
  90         {AUTO_RP_PIM_VERSION_1,       "Version 1"},
  91         {AUTO_RP_PIM_VERSION_2,       "Version 2"},
  92         {AUTO_RP_PIM_VERSION_DUAL,    "Dual version 1 and 2"},
  93         {0,                           NULL}
  94 };
  95
  96 #define AUTO_RP_GROUP_MASK_SIGN_POS 0
  97 #define AUTO_RP_GROUP_MASK_SIGN_NEG 1
  98 static const value_string auto_rp_mask_sign_vals[] = {
  99         {AUTO_RP_GROUP_MASK_SIGN_POS,  "Positive group prefix"},
 100         {AUTO_RP_GROUP_MASK_SIGN_NEG,  "Negative group prefix"},
 101         {0,                            NULL}
 102 };
 103
 104 static int do_auto_rp_map(wmem_allocator_t *scope, tvbuff_t *tvb, int offset, proto_tree *auto_rp_tree);
 105
 106 static int dissect_auto_rp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 107 {
 108         uint8_t ver_type, rp_count;
 109
 110         col_set_str(pinfo->cinfo, COL_PROTOCOL, "Auto-RP");
 111         col_clear(pinfo->cinfo, COL_INFO);
 112
 113         ver_type = tvb_get_uint8(tvb, 0);
 114         rp_count = tvb_get_uint8(tvb, 1);
 115         col_add_fstr(pinfo->cinfo, COL_INFO, "%s (v%s) for %u RP%s",
 116                      val_to_str_const(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"),
 117                      val_to_str_const(hi_nibble(ver_type), auto_rp_ver_vals,  "Unknown"),
 118                      rp_count, plurality(rp_count, "", "s"));
 119
 120         if (tree) {
 121                 proto_item *ti;
 122                 proto_tree *auto_rp_tree, *ver_type_tree;
 123                 int         i, offset;
 124                 uint16_t    holdtime;
 125
 126                 offset = 0;
 127                 ti = proto_tree_add_item(tree, proto_auto_rp, tvb, offset, -1, ENC_NA);
 128                 auto_rp_tree = proto_item_add_subtree(ti, ett_auto_rp);
 129
 130                 ver_type_tree = proto_tree_add_subtree_format(auto_rp_tree, tvb, offset, 1,
 131                                          ett_auto_rp_ver_type, NULL, "Version: %s, Packet type: %s",
 132                                          val_to_str_const(hi_nibble(ver_type), auto_rp_ver_vals,  "Unknown"),
 133                                          val_to_str_const(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"));
 134                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_version, tvb, offset, 1, ver_type);
 135                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_type, tvb, offset, 1, ver_type);
 136                 offset++;
 137
 138                 proto_tree_add_uint(auto_rp_tree, hf_auto_rp_count, tvb, offset, 1, rp_count);
 139                 offset++;
 140
 141                 holdtime = tvb_get_ntohs(tvb, offset);
 142                 proto_tree_add_uint_format_value(auto_rp_tree, hf_auto_rp_holdtime, tvb, offset, 2, holdtime,
 143                                            "%u second%s", holdtime, plurality(holdtime, "", "s"));
 144                 offset+=2;
 145
 146                 proto_tree_add_item(auto_rp_tree, hf_auto_rp_reserved, tvb, offset, 4, ENC_BIG_ENDIAN);
 147                 offset+=4;
 148
 149                 for (i = 0; i < rp_count; i++)
 150                         offset = do_auto_rp_map(pinfo->pool, tvb, offset, auto_rp_tree);
 151
 152                 if (tvb_reported_length_remaining(tvb, offset) > 0)
 153                         proto_tree_add_item(tree, hf_auto_rp_trailing_junk, tvb, offset, -1, ENC_NA);
 154         }
 155
 156         return tvb_captured_length(tvb);
 157 }
 158
 159 /*
 160  * Handles one Auto-RP map entry. Returns the new offset.
 161  */
 162 static int do_auto_rp_map(wmem_allocator_t *scope, tvbuff_t *tvb, int offset, proto_tree *auto_rp_tree)
 163 {
 164         proto_tree *map_tree;
 165         uint8_t     group_count;
 166         int         i;
 167
 168         group_count = tvb_get_uint8(tvb, offset + 5);
 169
 170         /* sizeof map header + n * sizeof encoded group addresses */
 171         map_tree = proto_tree_add_subtree_format(auto_rp_tree, tvb, offset, 6 + group_count * 6,
 172                                  ett_auto_rp_map, NULL,
 173                                  "RP %s: %u group%s", tvb_ip_to_str(scope, tvb, offset),
 174                                  group_count, plurality(group_count, "", "s"));
 175
 176         proto_tree_add_item(map_tree, hf_auto_rp_rp_addr, tvb, offset, 4, ENC_BIG_ENDIAN);
 177         offset += 4;
 178         proto_tree_add_item(map_tree, hf_auto_rp_pim_ver, tvb, offset, 1, ENC_BIG_ENDIAN);
 179         offset++;
 180         proto_tree_add_uint(map_tree, hf_auto_rp_group_num, tvb, offset, 1, group_count);
 181         offset++;
 182
 183         for (i = 0; i < group_count; i++) {
 184                 proto_tree *grp_tree;
 185                 uint8_t     sign, mask_len;
 186
 187                 sign = tvb_get_uint8(tvb, offset);
 188                 mask_len = tvb_get_uint8(tvb, offset + 1);
 189                 grp_tree = proto_tree_add_subtree_format(map_tree, tvb, offset, 6,
 190                                          ett_auto_rp_group, NULL, "Group %s/%u (%s)",
 191                                          tvb_ip_to_str(scope, tvb, offset + 2), mask_len,
 192                                          val_to_str_const(sign&AUTO_RP_SIGN_MASK, auto_rp_mask_sign_vals, ""));
 193
 194                 proto_tree_add_uint(grp_tree, hf_auto_rp_prefix_sgn, tvb, offset, 1, sign);
 195                 offset++;
 196                 proto_tree_add_uint(grp_tree, hf_auto_rp_mask_len, tvb, offset, 1, mask_len);
 197                 offset++;
 198                 proto_tree_add_item(grp_tree, hf_auto_rp_group_prefix, tvb, offset, 4, ENC_BIG_ENDIAN);
 199                 offset += 4;
 200
 201         }
 202
 203         return offset;
 204 }
 205
 206 void proto_register_auto_rp(void)
 207 {
 208         static hf_register_info hf[] = {
 209                 { &hf_auto_rp_version,
 210                   {"Protocol version", "auto_rp.version",
 211                    FT_UINT8, BASE_DEC, VALS(auto_rp_ver_vals), AUTO_RP_VERSION_MASK,
 212                    "Auto-RP protocol version", HFILL }},
 213
 214                 { &hf_auto_rp_type,
 215                   {"Packet type", "auto_rp.type",
 216                    FT_UINT8, BASE_DEC, VALS(auto_rp_type_vals), AUTO_RP_TYPE_MASK,
 217                    "Auto-RP packet type", HFILL }},
 218
 219                 { &hf_auto_rp_count,
 220                   {"RP count", "auto_rp.rp_count",
 221                    FT_UINT8, BASE_DEC, NULL, 0,
 222                    "The number of RP addresses contained in this message", HFILL }},
 223
 224                 { &hf_auto_rp_group_num,
 225                   {"Number of groups this RP maps to", "auto_rp.group_num",
 226                    FT_UINT8, BASE_DEC, NULL, 0,
 227                    NULL, HFILL }},
 228
 229                 { &hf_auto_rp_holdtime,
 230                   {"Holdtime", "auto_rp.holdtime",
 231                    FT_UINT16, BASE_DEC, NULL, 0,
 232                    "The amount of time in seconds this announcement is valid", HFILL }},
 233
 234                 { &hf_auto_rp_pim_ver,
 235                   {"Version", "auto_rp.pim_ver",
 236                    FT_UINT8, BASE_DEC, VALS(auto_rp_pim_ver_vals), AUTO_RP_PIM_VER_MASK,
 237                    "RP's highest PIM version", HFILL }},
 238
 239                 { &hf_auto_rp_rp_addr,
 240                   {"RP address", "auto_rp.rp_addr",
 241                    FT_IPv4, BASE_NONE, NULL, 0,
 242                    "The unicast IP address of the RP", HFILL }},
 243
 244                 { &hf_auto_rp_prefix_sgn,
 245                   {"Sign", "auto_rp.prefix_sign",
 246                    FT_UINT8, BASE_DEC, VALS(auto_rp_mask_sign_vals), AUTO_RP_SIGN_MASK,
 247                    "Group prefix sign", HFILL }},
 248
 249                 { &hf_auto_rp_mask_len,
 250                   {"Mask length", "auto_rp.mask_len",
 251                    FT_UINT8, BASE_DEC, NULL, 0x0,
 252                    "Length of group prefix", HFILL }},
 253
 254                 { &hf_auto_rp_group_prefix,
 255                   {"Prefix", "auto_rp.group_prefix",
 256                    FT_IPv4, BASE_NONE, NULL, 0,
 257                    "Group prefix", HFILL }},
 258
 259                 { &hf_auto_rp_reserved,
 260                   {"Reserved", "auto_rp.reserved",
 261                    FT_UINT32, BASE_HEX, NULL, 0,
 262                    NULL, HFILL }},
 263
 264                 { &hf_auto_rp_trailing_junk,
 265                   {"Trailing junk", "auto_rp.trailing_junk",
 266                    FT_BYTES, BASE_NONE, NULL, 0,
 267                    NULL, HFILL }},
 268         };
 269
 270         static int *ett[] = {
 271                 &ett_auto_rp,
 272                 &ett_auto_rp_ver_type,
 273                 &ett_auto_rp_map,
 274                 &ett_auto_rp_group
 275         };
 276
 277         proto_auto_rp = proto_register_protocol("Cisco Auto-RP", "Auto-RP", "auto_rp");
 278         proto_register_field_array(proto_auto_rp, hf, array_length(hf));
 279         proto_register_subtree_array(ett, array_length(ett));
 280
 281         auto_rp_handle = register_dissector("auto_rp", dissect_auto_rp, proto_auto_rp);
 282 }
 283
 284 void
 285 proto_reg_handoff_auto_rp(void)
 286 {
 287         dissector_add_uint_with_preference("udp.port", UDP_PORT_PIM_RP_DISC, auto_rp_handle);
 288 }
 289
 290 /*
 291  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 292  *
 293  * Local variables:
 294  * c-basic-offset: 8
 295  * tab-width: 8
 296  * indent-tabs-mode: nil
 297  * End:
 298  *
 299  * vi: set shiftwidth=8 tabstop=8 expandtab:
 300  * :indentSize=8:tabSize=8:noTabs=true:
 301  */