forked from osmocom/wireshark
355 lines
12 KiB
C
355 lines
12 KiB
C
/* packet-vrrp.c
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* Routines for the Virtual Router Redundancy Protocol (VRRP)
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*
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* VRRPv2: RFC3768 (superseeding RFC2338)
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* VRRPv3: RFC5798
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*
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* Heikki Vatiainen <hessu@cs.tut.fi>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/ipproto.h>
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#include <epan/in_cksum.h>
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#include <epan/expert.h>
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#include <epan/prefs.h>
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void proto_register_vrrp(void);
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void proto_reg_handoff_vrrp(void);
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static gint proto_vrrp = -1;
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static gint ett_vrrp = -1;
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static gint ett_vrrp_ver_type = -1;
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static gint hf_vrrp_ver_type = -1;
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static gint hf_vrrp_version = -1;
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static gint hf_vrrp_type = -1;
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static gint hf_vrrp_virt_rtr_id = -1;
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static gint hf_vrrp_prio = -1;
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static gint hf_vrrp_addr_count = -1;
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static gint hf_vrrp_checksum = -1;
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static gint hf_vrrp_checksum_status = -1;
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static gint hf_vrrp_auth_type = -1;
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static gint hf_vrrp_adver_int = -1;
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static gint hf_vrrp_reserved_mbz = -1;
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static gint hf_vrrp_short_adver_int = -1;
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static gint hf_vrrp_ip = -1;
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static gint hf_vrrp_ip6 = -1;
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static gint hf_vrrp_auth_string = -1;
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static gint hf_vrrp_md5_auth_data = -1;
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static gboolean g_vrrp_v3_checksum_as_in_v2 = FALSE;
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static expert_field ei_vrrp_checksum = EI_INIT;
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#define VRRP_VERSION_MASK 0xf0
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#define VRRP_TYPE_MASK 0x0f
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#define VRRP_AUTH_DATA_LEN 8
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#define VRRP_TYPE_ADVERTISEMENT 1
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static const value_string vrrp_type_vals[] = {
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{VRRP_TYPE_ADVERTISEMENT, "Advertisement"},
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{0, NULL}
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};
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#define VRRP_AUTH_TYPE_NONE 0
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#define VRRP_AUTH_TYPE_SIMPLE_TEXT 1
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#define VRRP_AUTH_TYPE_IP_AUTH_HDR 2
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#define VRRP_AUTH_TYPE_IP_MD5 254
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static const value_string vrrp_auth_vals[] = {
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{VRRP_AUTH_TYPE_NONE, "No Authentication"},
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{VRRP_AUTH_TYPE_SIMPLE_TEXT, "Simple Text Authentication [RFC 2338] / Reserved [RFC 3768]"},
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{VRRP_AUTH_TYPE_IP_AUTH_HDR, "IP Authentication Header [RFC 2338] / Reserved [RFC 3768]"},
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{VRRP_AUTH_TYPE_IP_MD5, "Cisco VRRP MD5 authentication"},
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{0, NULL}
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};
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#define VRRP_PRIORITY_MASTER_STOPPING 0
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/* Values between 1 and 254 inclusive are for backup VRRP routers */
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#define VRRP_PRIORITY_DEFAULT 100
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#define VRRP_PRIORITY_OWNER 255
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static const value_string vrrp_prio_vals[] = {
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{VRRP_PRIORITY_MASTER_STOPPING, "Current Master has stopped participating in VRRP"},
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{VRRP_PRIORITY_DEFAULT, "Default priority for a backup VRRP router"},
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{VRRP_PRIORITY_OWNER, "This VRRP router owns the virtual router's IP address(es)"},
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{0, NULL }
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};
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static int
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dissect_vrrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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int offset = 0;
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gint vrrp_len;
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guint8 ver_type;
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vec_t cksum_vec[4];
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guint32 phdr[2];
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gboolean is_ipv6;
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proto_item *ti, *tv;
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proto_tree *vrrp_tree, *ver_type_tree;
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guint8 priority, addr_count = 0, auth_type = VRRP_AUTH_TYPE_NONE;
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guint16 computed_cksum = 0;
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is_ipv6 = (pinfo->src.type == AT_IPv6);
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "VRRP");
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col_clear(pinfo->cinfo, COL_INFO);
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ver_type = tvb_get_guint8(tvb, 0);
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col_add_fstr(pinfo->cinfo, COL_INFO, "Announcement (v%u)",
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hi_nibble(ver_type));
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ti = proto_tree_add_item(tree, proto_vrrp, tvb, 0, -1, ENC_NA);
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vrrp_tree = proto_item_add_subtree(ti, ett_vrrp);
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priority = tvb_get_guint8(tvb, 2);
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addr_count = tvb_get_guint8(tvb, 3);
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tv = proto_tree_add_uint_format(vrrp_tree, hf_vrrp_ver_type,
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tvb, offset, 1, ver_type,
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"Version %u, Packet type %u (%s)",
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hi_nibble(ver_type), lo_nibble(ver_type),
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val_to_str_const(lo_nibble(ver_type), vrrp_type_vals, "Unknown"));
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ver_type_tree = proto_item_add_subtree(tv, ett_vrrp_ver_type);
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if(ver_type_tree){
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proto_tree_add_uint(ver_type_tree, hf_vrrp_version, tvb,
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offset, 1, ver_type);
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proto_tree_add_uint(ver_type_tree, hf_vrrp_type, tvb, offset, 1, ver_type);
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offset += 1;
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proto_tree_add_item(vrrp_tree, hf_vrrp_virt_rtr_id, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset += 1;
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proto_tree_add_uint_format(vrrp_tree, hf_vrrp_prio, tvb, offset, 1, priority, "Priority: %u (%s)",
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priority,
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val_to_str_const(priority, vrrp_prio_vals, "Non-default backup priority"));
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offset += 1;
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proto_tree_add_uint(vrrp_tree, hf_vrrp_addr_count, tvb,
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offset, 1, addr_count);
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offset += 1;
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switch(hi_nibble(ver_type)) {
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case 3:
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/* 4 bits reserved (mbz) + 12 bits interval */
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proto_tree_add_item(vrrp_tree, hf_vrrp_reserved_mbz, tvb, offset, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(vrrp_tree, hf_vrrp_short_adver_int, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset += 2;
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break;
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case 2:
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default:
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/* 1 byte auth type + 1 byte interval */
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auth_type = tvb_get_guint8(tvb, offset);
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proto_tree_add_item(vrrp_tree, hf_vrrp_auth_type, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset += 1;
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proto_tree_add_item(vrrp_tree, hf_vrrp_adver_int, tvb, offset, 1, ENC_BIG_ENDIAN);
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offset += 1;
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break;
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}
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}else{
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offset += 6;
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}
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vrrp_len = (gint)tvb_reported_length(tvb);
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if (!pinfo->fragmented && (gint)tvb_captured_length(tvb) >= vrrp_len) {
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/* The packet isn't part of a fragmented datagram
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and isn't truncated, so we can checksum it. */
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switch(hi_nibble(ver_type)) {
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case 3:
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if((g_vrrp_v3_checksum_as_in_v2 == FALSE)||(pinfo->src.type == AT_IPv6)){
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/* Set up the fields of the pseudo-header. */
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SET_CKSUM_VEC_PTR(cksum_vec[0], (const guint8 *)pinfo->src.data, pinfo->src.len);
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SET_CKSUM_VEC_PTR(cksum_vec[1], (const guint8 *)pinfo->dst.data, pinfo->dst.len);
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phdr[0] = g_htonl(vrrp_len);
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phdr[1] = g_htonl(IP_PROTO_VRRP);
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SET_CKSUM_VEC_PTR(cksum_vec[2], (const guint8 *)&phdr, 8);
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SET_CKSUM_VEC_TVB(cksum_vec[3], tvb, 0, vrrp_len);
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computed_cksum = in_cksum(cksum_vec, 4);
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break;
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}
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/* FALL THROUGH */
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case 2:
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default:
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SET_CKSUM_VEC_TVB(cksum_vec[0], tvb, 0, vrrp_len);
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computed_cksum = in_cksum(&cksum_vec[0], 1);
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break;
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}
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proto_tree_add_checksum(vrrp_tree, tvb, offset, hf_vrrp_checksum, hf_vrrp_checksum_status, &ei_vrrp_checksum, pinfo, computed_cksum,
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ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_IN_CKSUM);
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} else {
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proto_tree_add_checksum(vrrp_tree, tvb, offset, hf_vrrp_checksum, hf_vrrp_checksum_status, &ei_vrrp_checksum, pinfo, 0,
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ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
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}
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offset += 2;
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while (addr_count > 0) {
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if (is_ipv6) {
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proto_tree_add_item(vrrp_tree, hf_vrrp_ip6, tvb, offset, 16, ENC_NA);
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offset += 16;
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} else {
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proto_tree_add_item(vrrp_tree, hf_vrrp_ip, tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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}
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addr_count--;
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}
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if (auth_type == VRRP_AUTH_TYPE_SIMPLE_TEXT) {
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proto_tree_add_item(vrrp_tree, hf_vrrp_auth_string, tvb, offset, VRRP_AUTH_DATA_LEN, ENC_ASCII|ENC_NA);
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offset += VRRP_AUTH_DATA_LEN;
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} else if (auth_type == VRRP_AUTH_TYPE_IP_MD5) {
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if (vrrp_len - offset >= 16) {
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proto_tree_add_item(vrrp_tree, hf_vrrp_md5_auth_data, tvb, vrrp_len - 16, 16, ENC_NA);
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}
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}
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return offset;
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}
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void proto_register_vrrp(void)
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{
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static hf_register_info hf[] = {
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{ &hf_vrrp_ver_type,
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{"VRRP message version and type", "vrrp.typever",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"VRRP version and type", HFILL }},
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{ &hf_vrrp_version,
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{"VRRP protocol version", "vrrp.version",
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FT_UINT8, BASE_DEC, NULL, VRRP_VERSION_MASK,
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"VRRP version", HFILL }},
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{ &hf_vrrp_type,
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{"VRRP packet type", "vrrp.type",
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FT_UINT8, BASE_DEC, VALS(vrrp_type_vals), VRRP_TYPE_MASK,
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"VRRP type", HFILL }},
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{ &hf_vrrp_virt_rtr_id,
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{"Virtual Rtr ID", "vrrp.virt_rtr_id",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Virtual router this packet is reporting status for", HFILL }},
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{ &hf_vrrp_prio,
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{"Priority", "vrrp.prio",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Sending VRRP router's priority for the virtual router", HFILL }},
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{ &hf_vrrp_addr_count,
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{"Addr Count", "vrrp.addr_count",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"The number of addresses contained in this VRRP advertisement", HFILL }},
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{ &hf_vrrp_checksum,
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{ "Checksum", "vrrp.checksum",
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FT_UINT16, BASE_HEX, NULL, 0x0,
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"Used to detect data corruption in the VRRP message", HFILL }},
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{ &hf_vrrp_checksum_status,
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{ "Checksum Status", "vrrp.checksum.status",
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FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
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NULL, HFILL }},
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{ &hf_vrrp_auth_type,
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{"Auth Type", "vrrp.auth_type",
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FT_UINT8, BASE_DEC, VALS(vrrp_auth_vals), 0x0,
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"The authentication method being utilized", HFILL }},
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{ &hf_vrrp_adver_int,
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{"Adver Int", "vrrp.adver_int",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Time interval (in seconds) between ADVERTISEMENTS", HFILL }},
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{ &hf_vrrp_reserved_mbz,
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{"Reserved", "vrrp.reserved_mbz",
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FT_UINT8, BASE_DEC, NULL, 0xF0,
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"Must be zero", HFILL }},
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{ &hf_vrrp_short_adver_int,
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{"Adver Int", "vrrp.short_adver_int",
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FT_UINT16, BASE_DEC, NULL, 0x0FFF,
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"Time interval (in centiseconds) between ADVERTISEMENTS", HFILL }},
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{ &hf_vrrp_ip,
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{"IP Address", "vrrp.ip_addr",
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FT_IPv4, BASE_NONE, NULL, 0x0,
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"IP address associated with the virtual router", HFILL }},
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{ &hf_vrrp_ip6,
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{"IPv6 Address", "vrrp.ipv6_addr",
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FT_IPv6, BASE_NONE, NULL, 0x0,
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"IPv6 address associated with the virtual router", HFILL }},
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{ &hf_vrrp_auth_string,
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{"Authentication String", "vrrp.auth_string",
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FT_STRING, BASE_NONE, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_vrrp_md5_auth_data,
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{"MD5 Authentication Data", "vrrp.md5_auth_data",
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FT_BYTES, BASE_NONE, NULL, 0x0,
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"MD5 digest string is contained.", HFILL }},
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};
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static gint *ett[] = {
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&ett_vrrp,
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&ett_vrrp_ver_type
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};
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static ei_register_info ei[] = {
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{ &ei_vrrp_checksum, { "vrrp.checksum_bad.expert", PI_CHECKSUM, PI_WARN, "Bad checksum", EXPFILL }},
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};
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expert_module_t* expert_vrrp;
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module_t *vrrp_module;
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proto_vrrp = proto_register_protocol("Virtual Router Redundancy Protocol",
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"VRRP", "vrrp");
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proto_register_field_array(proto_vrrp, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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expert_vrrp = expert_register_protocol(proto_vrrp);
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expert_register_field_array(expert_vrrp, ei, array_length(ei));
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vrrp_module = prefs_register_protocol(proto_vrrp, NULL);
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prefs_register_bool_preference(vrrp_module, "v3_checksum_as_in_v2",
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"Calculate V3 checksum as in V2 for IPv4 packets",
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"There is some ambiguity on how to calculate V3 checksums"
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"As in V3 will use a pseudo header(which may only be implemented for IPv6 by some manufacturers)",
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&g_vrrp_v3_checksum_as_in_v2);
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}
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void
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proto_reg_handoff_vrrp(void)
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{
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dissector_handle_t vrrp_handle;
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vrrp_handle = create_dissector_handle(dissect_vrrp, proto_vrrp);
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dissector_add_uint("ip.proto", IP_PROTO_VRRP, vrrp_handle);
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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