/* packet-whois.c

 * Routines for whois dissection (see https://tools.ietf.org/html/rfc3912)

 * Copyright 2013, Christopher Maynard <Christopher.Maynard@gtech.com>

 *

 * 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/conversation.h>

#include <epan/expert.h>

#include "packet-tcp.h"

#define WHOIS_PORT      43  /* This is the registered IANA port (nicname) */

void proto_register_whois(void);

void proto_reg_handoff_whois(void);

static dissector_handle_t whois_handle;

static int proto_whois;

static int hf_whois_query;

static int hf_whois_answer;

static int hf_whois_answer_in;

static int hf_whois_answer_to;

static int hf_whois_response_time;

static expert_field ei_whois_nocrlf;

static expert_field ei_whois_encoding;

static int ett_whois;

typedef struct _whois_transaction_t {

    uint32_t req_frame;

    uint32_t rep_frame;

    nstime_t req_time;

    char*  query;

} whois_transaction_t;

static int

dissect_whois(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

    void *data)

{

    proto_item          *ti, *expert_ti;

    proto_tree          *whois_tree;

    conversation_t      *conversation;

    whois_transaction_t *whois_trans;

    bool                 is_query;

    unsigned             len;

    struct tcpinfo      *tcpinfo = (struct tcpinfo*)data;

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

    if (pinfo->destport == WHOIS_PORT) {

        is_query = true;

        col_set_str(pinfo->cinfo, COL_INFO, "Query");

    } else {

        is_query = false;

        col_set_str(pinfo->cinfo, COL_INFO, "Answer");

    }

    conversation = find_or_create_conversation(pinfo);

    whois_trans = (whois_transaction_t *)conversation_get_proto_data(conversation, proto_whois);

    if (whois_trans == NULL) {

        unsigned linelen;

        whois_trans = wmem_new0(wmem_file_scope(), whois_transaction_t);

        /*

         * Find the end of the first line.

         */

        tvb_find_line_end_remaining(tvb, 0, &linelen, NULL);

        whois_trans->query = (char*)tvb_get_string_enc(wmem_file_scope(), tvb, 0, linelen, ENC_ASCII|ENC_NA);

        conversation_add_proto_data(conversation, proto_whois, whois_trans);

    }

    if (whois_trans->query) {

        col_append_str(pinfo->cinfo, COL_INFO, ": ");

        col_append_str(pinfo->cinfo, COL_INFO, whois_trans->query);

    }

    len = tvb_reported_length(tvb);

    if (!PINFO_FD_VISITED(pinfo)) {

        if (pinfo->can_desegment) {

            if (is_query) {

                if ((len < 2) || (tvb_memeql(tvb, len - 2, (const uint8_t*)"\r\n", 2))) {

                    pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;

                    pinfo->desegment_offset = 0;

                    return -1;

                } else {

                    whois_trans->req_frame = pinfo->num;

                    whois_trans->req_time = pinfo->abs_ts;

                }

            } else if (!(tcpinfo && (IS_TH_FIN(tcpinfo->flags) || tcpinfo->is_reassembled))) {

                /* If this is the FIN (or already desegmented, as with an out

                 * of order segment received after FIN) go ahead and dissect

                 * on the first pass.

                 */

                pinfo->desegment_len = DESEGMENT_UNTIL_FIN;

                pinfo->desegment_offset = 0;

                return -1;

            }

        }

    } else if (is_query && (whois_trans->req_frame == 0)) {

        whois_trans->req_frame = pinfo->num;

        whois_trans->req_time = pinfo->abs_ts;

    }

    if (!is_query && (whois_trans->rep_frame == 0)) {

        /* By comparing whois_trans->rep_frame to 0, if reassembly is turned

         * on, whois_trans->rep_frame will be assigned to the reassembled frame

         * number, and if reassembly is turned off, whois_trans->rep_frame will

         * be assigned to the first frame number of the response.  This seems

         * to match other protocols' behavior.  The alternative is:

         *      if (pinfo->num > whois_trans->rep_frame)

         * which will give us the same frame number either way.

         */

        whois_trans->rep_frame = pinfo->num;

    }

    ti = proto_tree_add_protocol_format(tree, proto_whois, tvb, 0, -1,

        "WHOIS: %s", is_query ? "Query" : "Answer");

    whois_tree = proto_item_add_subtree(ti, ett_whois);

    /*

     * XXX - WHOIS, as RFC 3912 says, "has no mechanism for indicating

     * the character set in use."  We assume UTF-8, which is backwards

     * compatible with ASCII; if somebody wants to support WHOIS requests

     * or responses in other encodings, they should add a preference.

     * (Show Packet Bytes works well enough for many use cases.)

     * Some servers do use other character encodings;

     * e.g., in 2022 RIPE still uses ISO-8859-1.

     */

    if (is_query) {

        expert_ti = proto_tree_add_item(whois_tree, hf_whois_query, tvb, 0, -1, ENC_ASCII);

        if ((len < 2) || (tvb_memeql(tvb, len - 2, (const uint8_t*)"\r\n", 2))) {

            /*

             * From RFC3912, section 2:

             * All requests are terminated with ASCII CR and then ASCII LF.

             */

            expert_add_info(pinfo, expert_ti, &ei_whois_nocrlf);

        }

        if (tree && whois_trans->rep_frame) {

            ti = proto_tree_add_uint(whois_tree, hf_whois_answer_in,

                tvb, 0, 0, whois_trans->rep_frame);

            proto_item_set_generated(ti);

        }

    } else if (tree && whois_trans->rep_frame) {

        /*

         * If we know the request frame, show it and the time delta between

         * the request and the response.

         */

        if (whois_trans->req_frame) {

            nstime_t ns;

            ti = proto_tree_add_uint(whois_tree, hf_whois_answer_to,

                tvb, 0, 0, whois_trans->req_frame);

            proto_item_set_generated(ti);

            if (pinfo->num == whois_trans->rep_frame) {

                nstime_delta(&ns, &pinfo->abs_ts, &whois_trans->req_time);

                ti = proto_tree_add_time(whois_tree, hf_whois_response_time, tvb, 0, 0, &ns);

                proto_item_set_generated(ti);

            }

        }

        /*

         * Show the response as text, a line at a time.

         */

        unsigned offset = 0, next_offset;

        while (tvb_offset_exists(tvb, offset)) {

            /*

             * Find the end of the line.

             */

            tvb_find_line_end_remaining(tvb, offset, NULL, &next_offset);

            /*

             * Put this line.

             */

            proto_tree_add_item(whois_tree, hf_whois_answer, tvb, offset,

                next_offset - offset, ENC_UTF_8);

            offset = next_offset;

        }

        proto_tree_add_expert_remaining(whois_tree, pinfo, &ei_whois_encoding, tvb, 0);

    }

    return tvb_captured_length(tvb);

}

void

proto_register_whois(void)

{

    expert_module_t *expert_whois;

    static hf_register_info hf[] = {

        { &hf_whois_query,

            { "Query", "whois.query", FT_STRING, BASE_NONE, NULL, 0x0,

              NULL, HFILL }

        },

        { &hf_whois_answer,

            { "Answer", "whois.answer", FT_STRING, BASE_NONE, NULL, 0x0,

              NULL, HFILL }

        },

        { &hf_whois_answer_in,

            { "Answer In", "whois.answer_in", FT_FRAMENUM, BASE_NONE, FRAMENUM_TYPE(FT_FRAMENUM_RESPONSE),

              0x0, "The answer to this WHOIS query is in this frame",

              HFILL }

        },

        { &hf_whois_answer_to,

            { "Query In", "whois.answer_to", FT_FRAMENUM, BASE_NONE, FRAMENUM_TYPE(FT_FRAMENUM_REQUEST),

              0x0, "This is the answer to the WHOIS query in this frame",

              HFILL }

        },

        { &hf_whois_response_time,

            { "Response Time", "whois.response_time", FT_RELATIVE_TIME,

              BASE_NONE, NULL, 0x0,

              "The time between the Query and the Answer", HFILL }

        }

    };

    static int *ett[] = {

        &ett_whois

    };

    static ei_register_info ei[] = {

        { &ei_whois_nocrlf,

            { "whois.nocrlf", PI_MALFORMED, PI_WARN, "Missing <CR><LF>", EXPFILL}

        },

        { &ei_whois_encoding,

            { "whois.encoding", PI_ASSUMPTION, PI_CHAT, "WHOIS has no mechanism to indicate encoding (RFC 3912), assuming UTF-8", EXPFILL}

        }

    };

    proto_whois = proto_register_protocol("whois", "WHOIS", "whois");

    proto_register_field_array(proto_whois, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    expert_whois = expert_register_protocol(proto_whois);

    expert_register_field_array(expert_whois, ei, array_length(ei));

    whois_handle = register_dissector("whois", dissect_whois, proto_whois);

}

void

proto_reg_handoff_whois(void)

{

    dissector_add_uint_with_preference("tcp.port", WHOIS_PORT, whois_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:

 */