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: packet-auto_rp.c,v 1.21 2002/08/02 23:35:47 jmayer Exp $
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@ethereal.com>
  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/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         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 119                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "Auto-RP");
 120         if (check_col(pinfo->cinfo, COL_INFO))
 121                 col_clear(pinfo->cinfo, COL_INFO);
 122
 123         ver_type = tvb_get_guint8(tvb, 0);
 124         rp_count = tvb_get_guint8(tvb, 1);
 125         if (check_col(pinfo->cinfo, COL_INFO))
 126                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s (v%s) for %u RP%s",
 127                              val_to_str(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"),
 128                              val_to_str(hi_nibble(ver_type), auto_rp_ver_vals, "Unknown"),
 129                              rp_count, plurality(rp_count, "", "s"));
 130
 131         if (tree) {
 132                 proto_item *ti, *tv;
 133                 proto_tree *auto_rp_tree, *ver_type_tree;
 134                 int i, offset;
 135                 guint16 holdtime;
 136
 137                 offset = 0;
 138                 ti = proto_tree_add_item(tree, proto_auto_rp, tvb, offset, -1, FALSE);
 139                 auto_rp_tree = proto_item_add_subtree(ti, ett_auto_rp);
 140
 141                 tv = proto_tree_add_text(auto_rp_tree, tvb, offset, 1, "Version: %s, Packet type: %s",
 142                                          val_to_str(hi_nibble(ver_type), auto_rp_ver_vals, "Unknown"),
 143                                          val_to_str(lo_nibble(ver_type), auto_rp_type_vals, "Unknown"));
 144                 ver_type_tree = proto_item_add_subtree(tv, ett_auto_rp_ver_type);
 145                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_version, tvb, offset, 1, ver_type);
 146                 proto_tree_add_uint(ver_type_tree, hf_auto_rp_type, tvb, offset, 1, ver_type);
 147                 offset++;
 148
 149                 proto_tree_add_uint(auto_rp_tree, hf_auto_rp_count, tvb, offset, 1, rp_count);
 150                 offset++;
 151
 152                 holdtime = tvb_get_ntohs(tvb, offset);
 153                 proto_tree_add_uint_format(auto_rp_tree, hf_auto_rp_holdtime, tvb, offset, 2, holdtime,
 154                                            "Holdtime: %u second%s", holdtime, plurality(holdtime, "", "s"));
 155                 offset+=2;
 156
 157                 proto_tree_add_text(auto_rp_tree, tvb, offset, 4, "Reserved: 0x%x", tvb_get_ntohs(tvb, offset));
 158                 offset+=4;
 159
 160                 for (i = 0; i < rp_count; i++)
 161                         offset = do_auto_rp_map(tvb, offset, auto_rp_tree);
 162
 163                 if (tvb_offset_exists(tvb, offset))
 164                         proto_tree_add_text(tree, tvb, offset, -1, "Trailing junk");
 165         }
 166
 167         return;
 168 }
 169
 170 void proto_register_auto_rp(void)
 171 {
 172         static hf_register_info hf[] = {
 173                 { &hf_auto_rp_version,
 174                   {"Protocol version", "auto_rp.version",
 175                    FT_UINT8, BASE_DEC, VALS(auto_rp_ver_vals), AUTO_RP_VERSION_MASK,
 176                    "Auto-RP protocol version", HFILL }},
 177
 178                 { &hf_auto_rp_type,
 179                   {"Packet type", "auto_rp.type",
 180                    FT_UINT8, BASE_DEC, VALS(auto_rp_type_vals), AUTO_RP_TYPE_MASK,
 181                    "Auto-RP packet type", HFILL }},
 182
 183                 { &hf_auto_rp_count,
 184                   {"RP count", "auto_rp.rp_count",
 185                    FT_UINT8, BASE_DEC, NULL, 0,
 186                    "The number of RP addresses contained in this message", HFILL }},
 187
 188                 { &hf_auto_rp_holdtime,
 189                   {"Holdtime", "auto_rp.holdtime",
 190                    FT_UINT16, BASE_DEC, NULL, 0,
 191                    "The amount of time in seconds this announcement is valid", HFILL }},
 192
 193                 { &hf_auto_rp_pim_ver,
 194                   {"Version", "auto_rp.pim_ver",
 195                    FT_UINT8, BASE_DEC, VALS(auto_rp_pim_ver_vals), AUTO_RP_PIM_VER_MASK,
 196                    "RP's highest PIM version", HFILL }},
 197
 198                 { &hf_auto_rp_rp_addr,
 199                   {"RP address", "auto_rp.rp_addr",
 200                    FT_IPv4, 0, NULL, 0,
 201                    "The unicast IP address of the RP", HFILL }},
 202
 203                 { &hf_auto_rp_prefix_sgn,
 204                   {"Sign", "auto_rp.prefix_sign",
 205                    FT_UINT8, BASE_DEC, VALS(auto_rp_mask_sign_vals), AUTO_RP_SIGN_MASK,
 206                    "Group prefix sign", HFILL }},
 207
 208                 { &hf_auto_rp_mask_len,
 209                   {"Mask length", "auto_rp.mask_len",
 210                    FT_UINT8, BASE_BIN, NULL, 0x0,
 211                    "Length of group prefix", HFILL }},
 212
 213                 { &hf_auto_rp_group_prefix,
 214                   {"Prefix", "auto_rp.group_prefix",
 215                    FT_IPv4, 0, NULL, 0,
 216                    "Group prefix", HFILL }}
 217         };
 218
 219         static gint *ett[] = {
 220                 &ett_auto_rp,
 221                 &ett_auto_rp_ver_type,
 222                 &ett_auto_rp_map,
 223                 &ett_auto_rp_group
 224         };
 225
 226         proto_auto_rp = proto_register_protocol("Cisco Auto-RP",
 227             "Auto-RP", "auto_rp");
 228         proto_register_field_array(proto_auto_rp, hf, array_length(hf));
 229         proto_register_subtree_array(ett, array_length(ett));
 230
 231         return;
 232 }
 233
 234 void
 235 proto_reg_handoff_auto_rp(void)
 236 {
 237         dissector_handle_t auto_rp_handle;
 238
 239         auto_rp_handle = create_dissector_handle(dissect_auto_rp,
 240             proto_auto_rp);
 241         dissector_add("udp.port", UDP_PORT_PIM_RP_DISC, auto_rp_handle);
 242 }
 243
 244 /*
 245  * Handles one Auto-RP map entry. Returns the new offset.
 246  */
 247 static int do_auto_rp_map(tvbuff_t *tvb, int offset, proto_tree *auto_rp_tree)
 248 {
 249         proto_item *ti;
 250         proto_tree *map_tree;
 251         guint8 group_count;
 252         guint32 rp_addr;      /* In network byte order */
 253         int i;
 254
 255         tvb_memcpy(tvb, (guint8 *)&rp_addr, offset, 4);
 256         group_count = tvb_get_guint8(tvb, offset + 5);
 257
 258                                /* sizeof map header + n * sizeof encoded group addresses */
 259         ti = proto_tree_add_text(auto_rp_tree, tvb, offset, 6 + group_count * 6,
 260                                  "RP %s: %u group%s", ip_to_str((void *)&rp_addr),
 261                                  group_count, plurality(group_count, "", "s"));
 262         map_tree = proto_item_add_subtree(ti, ett_auto_rp_map);
 263
 264         proto_tree_add_ipv4(map_tree, hf_auto_rp_rp_addr, tvb, offset, 4, rp_addr);
 265         offset += 4;
 266         proto_tree_add_uint(map_tree, hf_auto_rp_pim_ver, tvb, offset, 1, tvb_get_guint8(tvb, offset));
 267         offset++;
 268         proto_tree_add_text(map_tree, tvb, offset, 1, "Number of groups this RP maps to: %u", group_count);
 269         offset++;
 270
 271         for (i = 0; i < group_count; i++) {
 272                 proto_item *gi;
 273                 proto_tree *grp_tree;
 274                 guint8 sign, mask_len;
 275                 guint32 group_addr;     /* In network byte order */
 276
 277                 sign = tvb_get_guint8(tvb, offset);
 278                 mask_len = tvb_get_guint8(tvb, offset + 1);
 279                 tvb_memcpy(tvb, (guint8 *)&group_addr, offset + 2, 4);
 280                 gi = proto_tree_add_text(map_tree, tvb, offset, 6, "Group %s/%u (%s)",
 281                                          ip_to_str((void *)&group_addr), mask_len,
 282                                          val_to_str(sign&AUTO_RP_SIGN_MASK, auto_rp_mask_sign_vals, ""));
 283                 grp_tree = proto_item_add_subtree(gi, ett_auto_rp_group);
 284
 285                 proto_tree_add_uint(grp_tree, hf_auto_rp_prefix_sgn, tvb, offset, 1, sign);
 286                 offset++;
 287                 proto_tree_add_uint(grp_tree, hf_auto_rp_mask_len, tvb, offset, 1, mask_len);
 288                 offset++;
 289                 proto_tree_add_ipv4(grp_tree, hf_auto_rp_group_prefix, tvb, offset, 4, group_addr);
 290                 offset += 4;
 291
 292         }
 293
 294         return offset;
 295 }