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  * $Id$
   8  *
   9  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  26  */
  27
  28 #include "config.h"
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32 #include <epan/to_str.h>
  33
  34 void proto_register_auto_rp(void);
  35 void proto_reg_handoff_auto_rp(void);
  36
  37 static gint proto_auto_rp = -1;
  38 static gint ett_auto_rp = -1;
  39 static gint ett_auto_rp_ver_type = -1;
  40 static gint ett_auto_rp_map = -1;
  41 static gint ett_auto_rp_group = -1;
  42
  43 static gint hf_auto_rp_version = -1;
  44 static gint hf_auto_rp_type = -1;
  45 static gint hf_auto_rp_count = -1;
  46 static gint hf_auto_rp_holdtime = -1;
  47 static gint hf_auto_rp_pim_ver = -1;
  48 static gint hf_auto_rp_rp_addr = -1;
  49 static gint hf_auto_rp_prefix_sgn = -1;
  50 static gint hf_auto_rp_mask_len = -1;
  51 static gint hf_auto_rp_group_prefix = -1;
  52
  53 #define UDP_PORT_PIM_RP_DISC 496
  54
  55 struct auto_rp_fixed_hdr {
  56 #define AUTO_RP_VERSION_MASK 0xf0
  57 #define AUTO_RP_TYPE_MASK    0x0f
  58         guint8  ver_type;       /* pim-autorp-spec01.txt defines version 1+ */
  59         guint8  rp_count;       /* Number of struct auto_rp_maps that follow the this header */
  60         guint16 holdtime;       /* Time in seconds this announcement is valid. 0 equals forever */
  61         guint32 reserved;
  62 };
  63
  64 struct auto_rp_map_hdr {
  65         guint32 rp_address;       /* The unicast IPv4 address of this RP */
  66 #define AUTO_RP_PIM_VER_MASK 0x03
  67         guint8  pim_version;      /* RP's highest PIM version. 2-bit field */
  68         guint8  group_count;      /* Number of encoded group addresses that follow this header */
  69 };
  70
  71 struct auto_rp_enc_grp_hdr {   /* Encoded group address */
  72 #define AUTO_RP_SIGN_MASK 0x01
  73         guint8  prefix_sgn;    /* 0 positive, 1 negative group prefix */
  74         guint8  mask_len;      /* Length of group prefix */
  75         guint32 addr;          /* Group prefix */
  76 };
  77
  78 #define AUTO_RP_VER_1PLUS 1
  79 static const value_string auto_rp_ver_vals[] = {
  80         {AUTO_RP_VER_1PLUS, "1 or 1+"},
  81         {0,                 NULL}
  82 };
  83
  84 #define AUTO_RP_TYPE_ANNOUNCEMENT 1
  85 #define AUTO_RP_TYPE_MAPPING      2
  86 static const value_string auto_rp_type_vals[] = {
  87         {AUTO_RP_TYPE_ANNOUNCEMENT, "RP announcement"},
  88         {AUTO_RP_TYPE_MAPPING,      "RP mapping"},
  89         {0,                         NULL}
  90 };
  91
  92 #define AUTO_RP_PIM_VERSION_UNKNOWN 0x00
  93 #define AUTO_RP_PIM_VERSION_1       0x01
  94 #define AUTO_RP_PIM_VERSION_2       0x02
  95 #define AUTO_RP_PIM_VERSION_DUAL    0x03
  96 static const value_string auto_rp_pim_ver_vals[] = {
  97         {AUTO_RP_PIM_VERSION_UNKNOWN, "Version unknown"},
  98         {AUTO_RP_PIM_VERSION_1,       "Version 1"},
  99         {AUTO_RP_PIM_VERSION_2,       "Version 2"},
 100         {AUTO_RP_PIM_VERSION_DUAL,    "Dual version 1 and 2"},
 101         {0,                           NULL}
 102 };
 103
 104 #define AUTO_RP_GROUP_MASK_SIGN_POS 0
 105 #define AUTO_RP_GROUP_MASK_SIGN_NEG 1
 106 static const value_string auto_rp_mask_sign_vals[] = {
 107         {AUTO_RP_GROUP_MASK_SIGN_POS,  "Positive group prefix"},
 108         {AUTO_RP_GROUP_MASK_SIGN_NEG,  "Negative group prefix"},
 109         {0,                            NULL}
 110 };
 111
 112 static int do_auto_rp_map(tvbuff_t *tvb, int offset, proto_tree *auto_rp_tree);
 113
 114 static void dissect_auto_rp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 115 {
 116         guint8 ver_type, rp_count;
 117
 118         col_set_str(pinfo->cinfo, COL_PROTOCOL, "Auto-RP");
 119         col_clear(pinfo->cinfo, COL_INFO);
 120
 121         ver_type = tvb_get_guint8(tvb, 0);
 122         rp_count = tvb_get_guint8(tvb, 1);
 123         col_add_fstr(pinfo->cinfo, COL_INFO, "%s (v%s) for %u RP%s",
 124                      val_to_str_const(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"),
 125                      val_to_str_const(hi_nibble(ver_type), auto_rp_ver_vals,  "Unknown"),
 126                      rp_count, plurality(rp_count, "", "s"));
 127
 128         if (tree) {
 129                 proto_item *ti, *tv;
 130                 proto_tree *auto_rp_tree, *ver_type_tree;
 131                 int         i, offset;
 132                 guint16     holdtime;
 133
 134                 offset = 0;
 135                 ti = proto_tree_add_item(tree, proto_auto_rp, tvb, offset, -1, ENC_NA);
 136                 auto_rp_tree = proto_item_add_subtree(ti, ett_auto_rp);
 137
 138                 tv = proto_tree_add_text(auto_rp_tree, tvb, offset, 1, "Version: %s, Packet type: %s",
 139                                          val_to_str_const(hi_nibble(ver_type), auto_rp_ver_vals,  "Unknown"),
 140                                          val_to_str_const(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"));
 141                 ver_type_tree = proto_item_add_subtree(tv, ett_auto_rp_ver_type);
 142                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_version, tvb, offset, 1, ver_type);
 143                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_type, tvb, offset, 1, ver_type);
 144                 offset++;
 145
 146                 proto_tree_add_uint(auto_rp_tree, hf_auto_rp_count, tvb, offset, 1, rp_count);
 147                 offset++;
 148
 149                 holdtime = tvb_get_ntohs(tvb, offset);
 150                 proto_tree_add_uint_format_value(auto_rp_tree, hf_auto_rp_holdtime, tvb, offset, 2, holdtime,
 151                                            "%u second%s", holdtime, plurality(holdtime, "", "s"));
 152                 offset+=2;
 153
 154                 proto_tree_add_text(auto_rp_tree, tvb, offset, 4, "Reserved: 0x%x", tvb_get_ntohs(tvb, offset));
 155                 offset+=4;
 156
 157                 for (i = 0; i < rp_count; i++)
 158                         offset = do_auto_rp_map(tvb, offset, auto_rp_tree);
 159
 160                 if (tvb_offset_exists(tvb, offset))
 161                         proto_tree_add_text(tree, tvb, offset, -1, "Trailing junk");
 162         }
 163
 164         return;
 165 }
 166
 167 /*
 168  * Handles one Auto-RP map entry. Returns the new offset.
 169  */
 170 static int do_auto_rp_map(tvbuff_t *tvb, int offset, proto_tree *auto_rp_tree)
 171 {
 172         proto_item *ti;
 173         proto_tree *map_tree;
 174         guint8      group_count;
 175         guint32     rp_addr;    /* In network byte order */
 176         int         i;
 177
 178         rp_addr = tvb_get_ipv4(tvb, offset);
 179         group_count = tvb_get_guint8(tvb, offset + 5);
 180
 181         /* sizeof map header + n * sizeof encoded group addresses */
 182         ti = proto_tree_add_text(auto_rp_tree, tvb, offset, 6 + group_count * 6,
 183                                  "RP %s: %u group%s", ip_to_str((guint8 *)&rp_addr),
 184                                  group_count, plurality(group_count, "", "s"));
 185         map_tree = proto_item_add_subtree(ti, ett_auto_rp_map);
 186
 187         proto_tree_add_ipv4(map_tree, hf_auto_rp_rp_addr, tvb, offset, 4, rp_addr);
 188         offset += 4;
 189         proto_tree_add_uint(map_tree, hf_auto_rp_pim_ver, tvb, offset, 1, tvb_get_guint8(tvb, offset));
 190         offset++;
 191         proto_tree_add_text(map_tree, tvb, offset, 1, "Number of groups this RP maps to: %u", group_count);
 192         offset++;
 193
 194         for (i = 0; i < group_count; i++) {
 195                 proto_item *gi;
 196                 proto_tree *grp_tree;
 197                 guint8      sign, mask_len;
 198                 guint32     group_addr; /* In network byte order */
 199
 200                 sign = tvb_get_guint8(tvb, offset);
 201                 mask_len = tvb_get_guint8(tvb, offset + 1);
 202                 group_addr = tvb_get_ipv4(tvb, offset + 2);
 203                 gi = proto_tree_add_text(map_tree, tvb, offset, 6, "Group %s/%u (%s)",
 204                                          ip_to_str((guint8 *)&group_addr), mask_len,
 205                                          val_to_str_const(sign&AUTO_RP_SIGN_MASK, auto_rp_mask_sign_vals, ""));
 206                 grp_tree = proto_item_add_subtree(gi, ett_auto_rp_group);
 207
 208                 proto_tree_add_uint(grp_tree, hf_auto_rp_prefix_sgn, tvb, offset, 1, sign);
 209                 offset++;
 210                 proto_tree_add_uint(grp_tree, hf_auto_rp_mask_len, tvb, offset, 1, mask_len);
 211                 offset++;
 212                 proto_tree_add_ipv4(grp_tree, hf_auto_rp_group_prefix, tvb, offset, 4, group_addr);
 213                 offset += 4;
 214
 215         }
 216
 217         return offset;
 218 }
 219
 220 void proto_register_auto_rp(void)
 221 {
 222         static hf_register_info hf[] = {
 223                 { &hf_auto_rp_version,
 224                   {"Protocol version", "auto_rp.version",
 225                    FT_UINT8, BASE_DEC, VALS(auto_rp_ver_vals), AUTO_RP_VERSION_MASK,
 226                    "Auto-RP protocol version", HFILL }},
 227
 228                 { &hf_auto_rp_type,
 229                   {"Packet type", "auto_rp.type",
 230                    FT_UINT8, BASE_DEC, VALS(auto_rp_type_vals), AUTO_RP_TYPE_MASK,
 231                    "Auto-RP packet type", HFILL }},
 232
 233                 { &hf_auto_rp_count,
 234                   {"RP count", "auto_rp.rp_count",
 235                    FT_UINT8, BASE_DEC, NULL, 0,
 236                    "The number of RP addresses contained in this message", HFILL }},
 237
 238                 { &hf_auto_rp_holdtime,
 239                   {"Holdtime", "auto_rp.holdtime",
 240                    FT_UINT16, BASE_DEC, NULL, 0,
 241                    "The amount of time in seconds this announcement is valid", HFILL }},
 242
 243                 { &hf_auto_rp_pim_ver,
 244                   {"Version", "auto_rp.pim_ver",
 245                    FT_UINT8, BASE_DEC, VALS(auto_rp_pim_ver_vals), AUTO_RP_PIM_VER_MASK,
 246                    "RP's highest PIM version", HFILL }},
 247
 248                 { &hf_auto_rp_rp_addr,
 249                   {"RP address", "auto_rp.rp_addr",
 250                    FT_IPv4, BASE_NONE, NULL, 0,
 251                    "The unicast IP address of the RP", HFILL }},
 252
 253                 { &hf_auto_rp_prefix_sgn,
 254                   {"Sign", "auto_rp.prefix_sign",
 255                    FT_UINT8, BASE_DEC, VALS(auto_rp_mask_sign_vals), AUTO_RP_SIGN_MASK,
 256                    "Group prefix sign", HFILL }},
 257
 258                 { &hf_auto_rp_mask_len,
 259                   {"Mask length", "auto_rp.mask_len",
 260                    FT_UINT8, BASE_DEC, NULL, 0x0,
 261                    "Length of group prefix", HFILL }},
 262
 263                 { &hf_auto_rp_group_prefix,
 264                   {"Prefix", "auto_rp.group_prefix",
 265                    FT_IPv4, BASE_NONE, NULL, 0,
 266                    "Group prefix", HFILL }}
 267         };
 268
 269         static gint *ett[] = {
 270                 &ett_auto_rp,
 271                 &ett_auto_rp_ver_type,
 272                 &ett_auto_rp_map,
 273                 &ett_auto_rp_group
 274         };
 275
 276         proto_auto_rp = proto_register_protocol("Cisco Auto-RP",
 277                                                 "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         return;
 282 }
 283
 284 void
 285 proto_reg_handoff_auto_rp(void)
 286 {
 287         dissector_handle_t auto_rp_handle;
 288
 289         auto_rp_handle = create_dissector_handle(dissect_auto_rp,
 290                                                  proto_auto_rp);
 291         dissector_add_uint("udp.port", UDP_PORT_PIM_RP_DISC, auto_rp_handle);
 292 }