/* packet-rip.c

 * Routines for RIPv1 and RIPv2 packet disassembly

 * RFC1058 (STD 34), RFC1388, RFC1723, RFC2453 (STD 56)

 * (c) Copyright Hannes R. Boehm <hannes@boehm.org>

 *

 * RFC2082 ( Keyed Message Digest Algorithm )

 *   Emanuele Caratti  <wiz@iol.it>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/expert.h>

#include <epan/prefs.h>

#include <epan/to_str.h>

#define UDP_PORT_RIP    520

#define RIPv1   1

#define RIPv2   2

void proto_register_rip(void);

void proto_reg_handoff_rip(void);

static const value_string version_vals[] = {

    { RIPv1, "RIPv1" },

    { RIPv2, "RIPv2" },

    { 0, NULL }

};

static const value_string command_vals[] = {

    { 1, "Request" },

    { 2, "Response" },

    { 3, "Traceon" },

    { 4, "Traceoff" },

    { 5, "Vendor specific (Sun)" },

    { 0, NULL }

};

#define AFVAL_UNSPEC    0

#define AFVAL_IP        2

static const value_string family_vals[] = {

    { AFVAL_UNSPEC, "Unspecified" },

    { AFVAL_IP,     "IP" },

    { 0, NULL }

};

#define AUTH_IP_ROUTE           1

#define AUTH_PASSWORD           2

#define AUTH_KEYED_MSG_DIGEST   3

static const value_string rip_auth_type[] = {

    { AUTH_IP_ROUTE,         "IP Route" },

    { AUTH_PASSWORD,         "Simple Password" },

    { AUTH_KEYED_MSG_DIGEST, "Keyed Message Digest" },

    { 0, NULL }

};

#define RIP_HEADER_LENGTH 4

#define RIP_ENTRY_LENGTH 20

#define MD5_AUTH_DATA_LEN 16

static bool pref_display_routing_domain;

static dissector_handle_t rip_handle;

static int proto_rip;

static int hf_rip_auth;

static int hf_rip_auth_data_len;

static int hf_rip_auth_passwd;

static int hf_rip_auth_seq_num;

static int hf_rip_authentication_data;

static int hf_rip_command;

static int hf_rip_digest_offset;

static int hf_rip_family;

static int hf_rip_ip;

static int hf_rip_key_id;

static int hf_rip_metric;

static int hf_rip_netmask;

static int hf_rip_next_hop;

static int hf_rip_route_tag;

static int hf_rip_routing_domain;

static int hf_rip_version;

static int hf_rip_zero_padding;

static int ett_rip;

static int ett_rip_vec;

static int ett_auth_vec;

static expert_field ei_rip_unknown_address_family;

static void dissect_unspec_rip_vektor(tvbuff_t *tvb, int offset, uint8_t version,

    proto_tree *tree);

static void dissect_ip_rip_vektor(tvbuff_t *tvb, packet_info *pinfo, int offset, uint8_t version,

    proto_tree *tree);

static unsigned dissect_rip_authentication(tvbuff_t *tvb, packet_info* pinfo, int offset,

    proto_tree *tree);

static int

dissect_rip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

    int         offset      = 0;

    proto_tree *rip_tree    = NULL;

    proto_item *ti;

    uint8_t     command;

    uint8_t     version;

    uint16_t    family;

    unsigned    trailer_len = 0;

    bool        is_md5_auth = false;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "RIP");

    col_clear(pinfo->cinfo, COL_INFO);

    command = tvb_get_uint8(tvb, 0);

    version = tvb_get_uint8(tvb, 1);

    col_set_str(pinfo->cinfo, COL_PROTOCOL,

                    val_to_str_const(version, version_vals, "RIP"));

    col_add_str(pinfo->cinfo, COL_INFO,

                    val_to_str(pinfo->pool, command, command_vals, "Unknown command (%u)"));

    ti = proto_tree_add_item(tree, proto_rip, tvb, 0, -1, ENC_NA);

    rip_tree = proto_item_add_subtree(ti, ett_rip);

    proto_tree_add_uint(rip_tree, hf_rip_command, tvb, 0, 1, command);

    proto_tree_add_uint(rip_tree, hf_rip_version, tvb, 1, 1, version);

    if (version == RIPv2 && pref_display_routing_domain == true)

        proto_tree_add_item(rip_tree, hf_rip_routing_domain, tvb, 2, 2,

                    ENC_BIG_ENDIAN);

    /* skip header */

    offset = RIP_HEADER_LENGTH;

    /* zero or more entries */

    while (tvb_reported_length_remaining(tvb, offset) > trailer_len ) {

        family = tvb_get_ntohs(tvb, offset);

        switch (family) {

        case AFVAL_UNSPEC: /* Unspecified */

            /*

                * There should be one entry in the request, and a metric

                * of infinity, meaning "show the entire routing table".

                */

            dissect_unspec_rip_vektor(tvb, offset, version, rip_tree);

            break;

        case AFVAL_IP: /* IP */

            dissect_ip_rip_vektor(tvb, pinfo, offset, version, rip_tree);

            break;

        case 0xFFFF:

            if( offset == RIP_HEADER_LENGTH ) {

                    trailer_len=dissect_rip_authentication(tvb, pinfo, offset, rip_tree);

                    is_md5_auth = true;

            break;

            }

            if(is_md5_auth && tvb_reported_length_remaining(tvb, offset) == 20)

                    break;

            /* Intentional fall through */ /* auth Entry MUST be the first! */

        default:

            proto_tree_add_expert_format(rip_tree, pinfo, &ei_rip_unknown_address_family, tvb, offset,

                            RIP_ENTRY_LENGTH, "Unknown address family %u", family);

            break;

        }

        offset += RIP_ENTRY_LENGTH;

    }

    return tvb_captured_length(tvb);

}

static void

dissect_unspec_rip_vektor(tvbuff_t *tvb, int offset, uint8_t version,

                      proto_tree *tree)

{

    proto_tree *rip_vektor_tree;

    uint32_t    metric;

    metric = tvb_get_ntohl(tvb, offset+16);

    rip_vektor_tree = proto_tree_add_subtree_format(tree, tvb, offset,

                             RIP_ENTRY_LENGTH, ett_rip_vec, NULL, "Address not specified, Metric: %u",

                             metric);

    proto_tree_add_item(rip_vektor_tree, hf_rip_family, tvb, offset, 2, ENC_BIG_ENDIAN);

    if (version == RIPv2) {

        proto_tree_add_item(rip_vektor_tree, hf_rip_route_tag, tvb, offset+2, 2,

                        ENC_BIG_ENDIAN);

        proto_tree_add_item(rip_vektor_tree, hf_rip_netmask, tvb, offset+8, 4,

                            ENC_BIG_ENDIAN);

        proto_tree_add_item(rip_vektor_tree, hf_rip_next_hop, tvb, offset+12, 4,

                            ENC_BIG_ENDIAN);

    }

    proto_tree_add_uint(rip_vektor_tree, hf_rip_metric, tvb,

                        offset+16, 4, metric);

}

static void

dissect_ip_rip_vektor(tvbuff_t *tvb, packet_info *pinfo, int offset, uint8_t version,

                      proto_tree *tree)

{

    proto_tree *rip_vektor_tree;

    uint32_t    metric;

    metric = tvb_get_ntohl(tvb, offset+16);

    rip_vektor_tree = proto_tree_add_subtree_format(tree, tvb, offset,

                             RIP_ENTRY_LENGTH, ett_rip_vec, NULL, "IP Address: %s, Metric: %u",

                             tvb_ip_to_str(pinfo->pool, tvb, offset+4), metric);

    proto_tree_add_item(rip_vektor_tree, hf_rip_family, tvb, offset, 2, ENC_BIG_ENDIAN);

    if (version == RIPv2) {

        proto_tree_add_item(rip_vektor_tree, hf_rip_route_tag, tvb, offset+2, 2,

                        ENC_BIG_ENDIAN);

    }

    proto_tree_add_item(rip_vektor_tree, hf_rip_ip, tvb, offset+4, 4, ENC_BIG_ENDIAN);

    if (version == RIPv2) {

        proto_tree_add_item(rip_vektor_tree, hf_rip_netmask, tvb, offset+8, 4,

                            ENC_BIG_ENDIAN);

        proto_tree_add_item(rip_vektor_tree, hf_rip_next_hop, tvb, offset+12, 4,

                            ENC_BIG_ENDIAN);

    }

    proto_tree_add_uint(rip_vektor_tree, hf_rip_metric, tvb,

                        offset+16, 4, metric);

}

static unsigned

dissect_rip_authentication(tvbuff_t *tvb, packet_info* pinfo, int offset, proto_tree *tree)

{

    proto_tree *rip_authentication_tree;

    uint16_t    authtype;

    uint32_t    digest_off, auth_data_len;

    auth_data_len = 0;

    authtype = tvb_get_ntohs(tvb, offset + 2);

    rip_authentication_tree = proto_tree_add_subtree_format(tree, tvb, offset, RIP_ENTRY_LENGTH,

                        ett_rip_vec, NULL, "Authentication: %s", val_to_str(pinfo->pool, authtype, rip_auth_type, "Unknown (%u)" ) );

    proto_tree_add_uint(rip_authentication_tree, hf_rip_auth, tvb, offset+2, 2,

                authtype);

    switch ( authtype ) {

    case AUTH_PASSWORD: /* Plain text password */

        proto_tree_add_item(rip_authentication_tree, hf_rip_auth_passwd,

                        tvb, offset+4, 16, ENC_ASCII);

        break;

    case AUTH_KEYED_MSG_DIGEST: /* Keyed MD5 rfc 2082 */

        digest_off = tvb_get_ntohs( tvb, offset+4 );

        proto_tree_add_item( rip_authentication_tree, hf_rip_digest_offset, tvb, offset+4, 2, ENC_BIG_ENDIAN);

        proto_tree_add_item( rip_authentication_tree, hf_rip_key_id, tvb, offset+6, 1, ENC_NA);

        auth_data_len = tvb_get_uint8( tvb, offset+7 );

        proto_tree_add_item( rip_authentication_tree, hf_rip_auth_data_len, tvb, offset+7, 1, ENC_NA);

        proto_tree_add_item( rip_authentication_tree, hf_rip_auth_seq_num, tvb, offset+8, 4, ENC_BIG_ENDIAN);

        proto_tree_add_item( rip_authentication_tree, hf_rip_zero_padding, tvb, offset+12, 8, ENC_ASCII);

        rip_authentication_tree = proto_tree_add_subtree( rip_authentication_tree, tvb, offset-4+digest_off,

                        MD5_AUTH_DATA_LEN+4, ett_auth_vec, NULL, "Authentication Data Trailer" );

        proto_tree_add_item( rip_authentication_tree, hf_rip_authentication_data, tvb, offset-4+digest_off+4,

                        MD5_AUTH_DATA_LEN, ENC_NA);

        break;

    }

    return auth_data_len;

}

void

proto_register_rip(void)

{

    static hf_register_info hf[] = {

        { &hf_rip_command,

            { "Command", "rip.command",

              FT_UINT8, BASE_DEC, VALS(command_vals), 0,

              "What type of RIP Command is this", HFILL }

        },

        { &hf_rip_version,

            { "Version", "rip.version",

              FT_UINT8, BASE_DEC, VALS(version_vals), 0,

              "Version of the RIP protocol", HFILL }

        },

        { &hf_rip_routing_domain,

            { "Routing Domain", "rip.routing_domain",

              FT_UINT16, BASE_DEC, NULL, 0,

              "RIPv2 Routing Domain", HFILL }

        },

        { &hf_rip_ip,

            { "IP Address", "rip.ip",

              FT_IPv4, BASE_NONE, NULL, 0,

              NULL, HFILL }

        },

        { &hf_rip_netmask,

            { "Netmask", "rip.netmask",

              FT_IPv4, BASE_NETMASK, NULL, 0,

              NULL, HFILL }

        },

        { &hf_rip_next_hop,

            { "Next Hop", "rip.next_hop",

              FT_IPv4, BASE_NONE, NULL, 0,

              "Next Hop router for this route", HFILL }

        },

        { &hf_rip_metric,

            { "Metric", "rip.metric",

              FT_UINT16, BASE_DEC, NULL, 0,

              "Metric for this route", HFILL }

        },

        { &hf_rip_auth,

            { "Authentication type", "rip.auth.type",

              FT_UINT16, BASE_DEC, VALS(rip_auth_type), 0,

              "Type of authentication", HFILL }

        },

        { &hf_rip_auth_passwd,

            { "Password", "rip.auth.passwd",

              FT_STRING, BASE_NONE, NULL, 0,

              "Authentication password", HFILL }

        },

        { &hf_rip_family,

            { "Address Family", "rip.family",

              FT_UINT16, BASE_DEC, VALS(family_vals), 0,

              NULL, HFILL }

        },

        { &hf_rip_route_tag,

            { "Route Tag", "rip.route_tag",

              FT_UINT16, BASE_DEC, NULL, 0,

              NULL, HFILL }

        },

        { &hf_rip_zero_padding,

            { "Zero adding", "rip.zero_padding",

              FT_STRING, BASE_NONE, NULL, 0,

              "Authentication password", HFILL }

        },

        { &hf_rip_digest_offset,

            { "Digest Offset", "rip.digest_offset",

              FT_UINT16, BASE_DEC, NULL, 0,

              NULL, HFILL }

        },

        { &hf_rip_key_id,

            { "Key ID", "rip.key_id",

              FT_UINT8, BASE_DEC, NULL, 0,

              NULL, HFILL }

        },

        { &hf_rip_auth_data_len,

            { "Auth Data Len", "rip.auth_data_len",

              FT_UINT8, BASE_DEC, NULL, 0,

              NULL, HFILL }

        },

        { &hf_rip_auth_seq_num,

            { "Seq num", "rip.seq_num",

              FT_UINT32, BASE_DEC, NULL, 0,

              NULL, HFILL }

        },

        { &hf_rip_authentication_data,

            { "Authentication Data", "rip.authentication_data",

              FT_BYTES, BASE_NONE, NULL, 0,

              NULL, HFILL }

        },

    };

    static int *ett[] = {

        &ett_rip,

        &ett_rip_vec,

        &ett_auth_vec,

    };

    static ei_register_info ei[] = {

        { &ei_rip_unknown_address_family, { "rip.unknown_address_family", PI_PROTOCOL, PI_WARN, "Unknown address family", EXPFILL }},

    };

    expert_module_t* expert_rip;

    module_t *rip_module;

    proto_rip = proto_register_protocol("Routing Information Protocol", "RIP", "rip");

    proto_register_field_array(proto_rip, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    expert_rip = expert_register_protocol(proto_rip);

    expert_register_field_array(expert_rip, ei, array_length(ei));

    rip_module = prefs_register_protocol(proto_rip, NULL);

    prefs_register_bool_preference(rip_module, "display_routing_domain", "Display Routing Domain field", "Display the third and forth bytes of the RIPv2 header as the Routing Domain field (introduced in RFC 1388 [January 1993] and obsolete as of RFC 1723 [November 1994])", &pref_display_routing_domain);

    rip_handle = register_dissector("rip", dissect_rip, proto_rip);

}

void

proto_reg_handoff_rip(void)

{

    dissector_add_uint_with_preference("udp.port", UDP_PORT_RIP, rip_handle);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local variables:

 * c-basic-offset: 4

 * tab-width: 8

 * indent-tabs-mode: nil

 * End:

 *

 * vi: set shiftwidth=4 tabstop=8 expandtab:

 * :indentSize=4:tabSize=8:noTabs=true:

 */