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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <string.h>
  33 #include <glib.h>
  34 #include <epan/packet.h>
  35 #include <epan/addr_resolv.h>
  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         if (check_col(pinfo->cinfo, COL_INFO))
 120                 col_clear(pinfo->cinfo, COL_INFO);
 121
 122         ver_type = tvb_get_guint8(tvb, 0);
 123         rp_count = tvb_get_guint8(tvb, 1);
 124         if (check_col(pinfo->cinfo, COL_INFO))
 125                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s (v%s) for %u RP%s",
 126                              val_to_str(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"),
 127                              val_to_str(hi_nibble(ver_type), auto_rp_ver_vals, "Unknown"),
 128                              rp_count, plurality(rp_count, "", "s"));
 129
 130         if (tree) {
 131                 proto_item *ti, *tv;
 132                 proto_tree *auto_rp_tree, *ver_type_tree;
 133                 int i, offset;
 134                 guint16 holdtime;
 135
 136                 offset = 0;
 137                 ti = proto_tree_add_item(tree, proto_auto_rp, tvb, offset, -1, FALSE);
 138                 auto_rp_tree = proto_item_add_subtree(ti, ett_auto_rp);
 139
 140                 tv = proto_tree_add_text(auto_rp_tree, tvb, offset, 1, "Version: %s, Packet type: %s",
 141                                          val_to_str(hi_nibble(ver_type), auto_rp_ver_vals, "Unknown"),
 142                                          val_to_str(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"));
 143                 ver_type_tree = proto_item_add_subtree(tv, ett_auto_rp_ver_type);
 144                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_version, tvb, offset, 1, ver_type);
 145                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_type, tvb, offset, 1, ver_type);
 146                 offset++;
 147
 148                 proto_tree_add_uint(auto_rp_tree, hf_auto_rp_count, tvb, offset, 1, rp_count);
 149                 offset++;
 150
 151                 holdtime = tvb_get_ntohs(tvb, offset);
 152                 proto_tree_add_uint_format_value(auto_rp_tree, hf_auto_rp_holdtime, tvb, offset, 2, holdtime,
 153                                            "%u second%s", holdtime, plurality(holdtime, "", "s"));
 154                 offset+=2;
 155
 156                 proto_tree_add_text(auto_rp_tree, tvb, offset, 4, "Reserved: 0x%x", tvb_get_ntohs(tvb, offset));
 157                 offset+=4;
 158
 159                 for (i = 0; i < rp_count; i++)
 160                         offset = do_auto_rp_map(tvb, offset, auto_rp_tree);
 161
 162                 if (tvb_offset_exists(tvb, offset))
 163                         proto_tree_add_text(tree, tvb, offset, -1, "Trailing junk");
 164         }
 165
 166         return;
 167 }
 168
 169 void proto_register_auto_rp(void)
 170 {
 171         static hf_register_info hf[] = {
 172                 { &hf_auto_rp_version,
 173                   {"Protocol version", "auto_rp.version",
 174                    FT_UINT8, BASE_DEC, VALS(auto_rp_ver_vals), AUTO_RP_VERSION_MASK,
 175                    "Auto-RP protocol version", HFILL }},
 176
 177                 { &hf_auto_rp_type,
 178                   {"Packet type", "auto_rp.type",
 179                    FT_UINT8, BASE_DEC, VALS(auto_rp_type_vals), AUTO_RP_TYPE_MASK,
 180                    "Auto-RP packet type", HFILL }},
 181
 182                 { &hf_auto_rp_count,
 183                   {"RP count", "auto_rp.rp_count",
 184                    FT_UINT8, BASE_DEC, NULL, 0,
 185                    "The number of RP addresses contained in this message", HFILL }},
 186
 187                 { &hf_auto_rp_holdtime,
 188                   {"Holdtime", "auto_rp.holdtime",
 189                    FT_UINT16, BASE_DEC, NULL, 0,
 190                    "The amount of time in seconds this announcement is valid", HFILL }},
 191
 192                 { &hf_auto_rp_pim_ver,
 193                   {"Version", "auto_rp.pim_ver",
 194                    FT_UINT8, BASE_DEC, VALS(auto_rp_pim_ver_vals), AUTO_RP_PIM_VER_MASK,
 195                    "RP's highest PIM version", HFILL }},
 196
 197                 { &hf_auto_rp_rp_addr,
 198                   {"RP address", "auto_rp.rp_addr",
 199                    FT_IPv4, BASE_NONE, NULL, 0,
 200                    "The unicast IP address of the RP", HFILL }},
 201
 202                 { &hf_auto_rp_prefix_sgn,
 203                   {"Sign", "auto_rp.prefix_sign",
 204                    FT_UINT8, BASE_DEC, VALS(auto_rp_mask_sign_vals), AUTO_RP_SIGN_MASK,
 205                    "Group prefix sign", HFILL }},
 206
 207                 { &hf_auto_rp_mask_len,
 208                   {"Mask length", "auto_rp.mask_len",
 209                    FT_UINT8, BASE_DEC, NULL, 0x0,
 210                    "Length of group prefix", HFILL }},
 211
 212                 { &hf_auto_rp_group_prefix,
 213                   {"Prefix", "auto_rp.group_prefix",
 214                    FT_IPv4, BASE_NONE, NULL, 0,
 215                    "Group prefix", HFILL }}
 216         };
 217
 218         static gint *ett[] = {
 219                 &ett_auto_rp,
 220                 &ett_auto_rp_ver_type,
 221                 &ett_auto_rp_map,
 222                 &ett_auto_rp_group
 223         };
 224
 225         proto_auto_rp = proto_register_protocol("Cisco Auto-RP",
 226             "Auto-RP", "auto_rp");
 227         proto_register_field_array(proto_auto_rp, hf, array_length(hf));
 228         proto_register_subtree_array(ett, array_length(ett));
 229
 230         return;
 231 }
 232
 233 void
 234 proto_reg_handoff_auto_rp(void)
 235 {
 236         dissector_handle_t auto_rp_handle;
 237
 238         auto_rp_handle = create_dissector_handle(dissect_auto_rp,
 239             proto_auto_rp);
 240         dissector_add("udp.port", UDP_PORT_PIM_RP_DISC, auto_rp_handle);
 241 }
 242
 243 /*
 244  * Handles one Auto-RP map entry. Returns the new offset.
 245  */
 246 static int do_auto_rp_map(tvbuff_t *tvb, int offset, proto_tree *auto_rp_tree)
 247 {
 248         proto_item *ti;
 249         proto_tree *map_tree;
 250         guint8 group_count;
 251         guint32 rp_addr;      /* In network byte order */
 252         int i;
 253
 254         rp_addr = tvb_get_ipv4(tvb, offset);
 255         group_count = tvb_get_guint8(tvb, offset + 5);
 256
 257                                /* sizeof map header + n * sizeof encoded group addresses */
 258         ti = proto_tree_add_text(auto_rp_tree, tvb, offset, 6 + group_count * 6,
 259                                  "RP %s: %u group%s", ip_to_str((void *)&rp_addr),
 260                                  group_count, plurality(group_count, "", "s"));
 261         map_tree = proto_item_add_subtree(ti, ett_auto_rp_map);
 262
 263         proto_tree_add_ipv4(map_tree, hf_auto_rp_rp_addr, tvb, offset, 4, rp_addr);
 264         offset += 4;
 265         proto_tree_add_uint(map_tree, hf_auto_rp_pim_ver, tvb, offset, 1, tvb_get_guint8(tvb, offset));
 266         offset++;
 267         proto_tree_add_text(map_tree, tvb, offset, 1, "Number of groups this RP maps to: %u", group_count);
 268         offset++;
 269
 270         for (i = 0; i < group_count; i++) {
 271                 proto_item *gi;
 272                 proto_tree *grp_tree;
 273                 guint8 sign, mask_len;
 274                 guint32 group_addr;     /* In network byte order */
 275
 276                 sign = tvb_get_guint8(tvb, offset);
 277                 mask_len = tvb_get_guint8(tvb, offset + 1);
 278                 group_addr = tvb_get_ipv4(tvb, offset + 2);
 279                 gi = proto_tree_add_text(map_tree, tvb, offset, 6, "Group %s/%u (%s)",
 280                                          ip_to_str((void *)&group_addr), mask_len,
 281                                          val_to_str(sign&AUTO_RP_SIGN_MASK, auto_rp_mask_sign_vals, ""));
 282                 grp_tree = proto_item_add_subtree(gi, ett_auto_rp_group);
 283
 284                 proto_tree_add_uint(grp_tree, hf_auto_rp_prefix_sgn, tvb, offset, 1, sign);
 285                 offset++;
 286                 proto_tree_add_uint(grp_tree, hf_auto_rp_mask_len, tvb, offset, 1, mask_len);
 287                 offset++;
 288                 proto_tree_add_ipv4(grp_tree, hf_auto_rp_group_prefix, tvb, offset, 4, group_addr);
 289                 offset += 4;
 290
 291         }
 292
 293         return offset;
 294 }