HACK: 2nd try to match RowsetProperties

[wireshark-wip.git] / epan / dissectors / packet-ftp.c

/* packet-ftp.c
 * Routines for ftp packet dissection
 * Copyright 1999, Richard Sharpe <rsharpe@ns.aus.com>
 * Copyright 2001, Juan Toledo <toledo@users.sourceforge.net> (Passive FTP)
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * Copied from packet-pop.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#include <string.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/strutil.h>
#include <epan/conversation.h>
#include <epan/expert.h>
#include <epan/wmem/wmem.h>

#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>     /* needed to define AF_ values on UNIX */
#endif
#ifdef HAVE_WINSOCK2_H
#include <winsock2.h>       /* needed to define AF_ values on Windows */
#endif
#ifdef NEED_INET_V6DEFS_H
#include "wsutil/inet_v6defs.h" /* if not a *NIX system */
#endif



static int proto_ftp = -1;
static int proto_ftp_data = -1;
static int hf_ftp_response = -1;
static int hf_ftp_request = -1;
static int hf_ftp_request_command = -1;
static int hf_ftp_request_arg = -1;
static int hf_ftp_response_code = -1;
static int hf_ftp_response_arg = -1;
static int hf_ftp_pasv_ip = -1 ;
static int hf_ftp_pasv_port = -1;
static int hf_ftp_pasv_nat = -1;
static int hf_ftp_active_ip = -1;
static int hf_ftp_active_port = -1;
static int hf_ftp_active_nat = -1;
static int hf_ftp_eprt_af = -1;
static int hf_ftp_eprt_ip = -1;
static int hf_ftp_eprt_ipv6 = -1;
static int hf_ftp_eprt_port = -1;
static int hf_ftp_epsv_ip = -1;
static int hf_ftp_epsv_ipv6 = -1;
static int hf_ftp_epsv_port = -1;

static gint ett_ftp = -1;
static gint ett_ftp_reqresp = -1;

static expert_field ei_ftp_eprt_args_invalid = EI_INIT;
static expert_field ei_ftp_epsv_args_invalid = EI_INIT;

static dissector_handle_t ftpdata_handle;

#define TCP_PORT_FTPDATA        20
#define TCP_PORT_FTP            21

static const value_string response_table[] = {
    { 110, "Restart marker reply" },
    { 120, "Service ready in nnn minutes" },
    { 125, "Data connection already open; transfer starting" },
    { 150, "File status okay; about to open data connection" },
    { 200, "Command okay" },
    { 202, "Command not implemented, superfluous at this site" },
    { 211, "System status, or system help reply" },
    { 212, "Directory status" },
    { 213, "File status" },
    { 214, "Help message" },
    { 215, "NAME system type" },
    { 220, "Service ready for new user" },
    { 221, "Service closing control connection" },
    { 225, "Data connection open; no transfer in progress" },
    { 226, "Closing data connection" },
    { 227, "Entering Passive Mode" },
    { 229, "Entering Extended Passive Mode" },
    { 230, "User logged in, proceed" },
    { 232, "User logged in, authorized by security data exchange" },
    { 234, "Security data exchange complete" },
    { 235, "Security data exchange completed successfully" },
    { 250, "Requested file action okay, completed" },
    { 257, "PATHNAME created" },
    { 331, "User name okay, need password" },
    { 332, "Need account for login" },
    { 334, "Requested security mechanism is ok" },
    { 335, "Security data is acceptable, more is required" },
    { 336, "Username okay, need password. Challenge is ..." },
    { 350, "Requested file action pending further information" },
    { 421, "Service not available, closing control connection" },
    { 425, "Can't open data connection" },
    { 426, "Connection closed; transfer aborted" },
    { 431, "Need some unavailable resource to process security" },
    { 450, "Requested file action not taken" },
    { 451, "Requested action aborted: local error in processing" },
    { 452, "Requested action not taken. Insufficient storage space in system" },
    { 500, "Syntax error, command unrecognized" },
    { 501, "Syntax error in parameters or arguments" },
    { 502, "Command not implemented" },
    { 503, "Bad sequence of commands" },
    { 504, "Command not implemented for that parameter" },
    { 522, "Network protocol not supported" },
    { 530, "Not logged in" },
    { 532, "Need account for storing files" },
    { 533, "Command protection level denied for policy reasons" },
    { 534, "Request denied for policy reasons" },
    { 535, "Failed security check (hash, sequence, etc)" },
    { 536, "Requested PROT level not supported by mechanism" },
    { 537, "Command protection level not supported by security mechanism" },
    { 550, "Requested action not taken: File unavailable" },
    { 551, "Requested action aborted: page type unknown" },
    { 552, "Requested file action aborted: Exceeded storage allocation" },
    { 553, "Requested action not taken: File name not allowed" },
    { 631, "Integrity protected reply" },
    { 632, "Confidentiality and integrity protected reply" },
    { 633, "Confidentiality protected reply" },
    { 0,   NULL }
};
static value_string_ext response_table_ext = VALUE_STRING_EXT_INIT(response_table);

#define EPRT_AF_IPv4 1
#define EPRT_AF_IPv6 2
static const value_string eprt_af_vals[] = {
    { EPRT_AF_IPv4, "IPv4" },
    { EPRT_AF_IPv6, "IPv6" },
    { 0, NULL }
};


/*
 * Parse the address and port information in a PORT command or in the
 * response to a PASV command.  Return TRUE if we found an address and
 * port, and supply the address and port; return FALSE if we didn't find
 * them.
 *
 * We ignore the IP address in the reply, and use the address from which
 * the request came.
 *
 * XXX - are there cases where they differ?  What if the FTP server is
 * behind a NAT box, so that the address it puts into the reply isn't
 * the address at which you should contact it?  Do all NAT boxes detect
 * FTP PASV replies and rewrite the address?  (I suspect not.)
 *
 * RFC 959 doesn't say much about the syntax of the 227 reply.
 *
 * A proposal from Dan Bernstein at
 *
 *  http://cr.yp.to/ftp/retr.html
 *
 * "recommend[s] that clients use the following strategy to parse the
 * response line: look for the first digit after the initial space; look
 * for the fourth comma after that digit; read two (possibly negative)
 * integers, separated by a comma; the TCP port number is p1*256+p2, where
 * p1 is the first integer modulo 256 and p2 is the second integer modulo
 * 256."
 *
 * wget 1.5.3 looks for a digit, although it doesn't handle negative
 * integers.
 *
 * The FTP code in the source of the cURL library, at
 *
 *  http://curl.haxx.se/lxr/source/lib/ftp.c
 *
 * says that cURL "now scans for a sequence of six comma-separated numbers
 * and will take them as IP+port indicators"; it loops, doing "sscanf"s
 * looking for six numbers separated by commas, stepping the start pointer
 * in the scanf one character at a time - i.e., it tries rather exhaustively.
 *
 * An optimization would be to scan for a digit, and start there, and if
 * the scanf doesn't find six values, scan for the next digit and try
 * again; this will probably succeed on the first try.
 *
 * The cURL code also says that "found reply-strings include":
 *
 *  "227 Entering Passive Mode (127,0,0,1,4,51)"
 *  "227 Data transfer will passively listen to 127,0,0,1,4,51"
 *  "227 Entering passive mode. 127,0,0,1,4,51"
 *
 * so it appears that you can't assume there are parentheses around
 * the address and port number.
 */
static gboolean
parse_port_pasv(const guchar *line, int linelen, guint32 *ftp_ip, guint16 *ftp_port,
    guint32 *pasv_offset, guint *ftp_ip_len, guint *ftp_port_len)
{
    char     *args;
    char     *p;
    guchar    c;
    int       i;
    int       ip_address[4], port[2];
    gboolean  ret = FALSE;

    /*
     * Copy the rest of the line into a null-terminated buffer.
     */
    args = wmem_strndup(wmem_packet_scope(), line, linelen);
    p = args;

    for (;;) {
        /*
         * Look for a digit.
         */
        while ((c = *p) != '\0' && !isdigit(c))
            p++;

        if (*p == '\0') {
            /*
             * We ran out of text without finding anything.
             */
            break;
        }

        /*
         * See if we have six numbers.
         */
        i = sscanf(p, "%d,%d,%d,%d,%d,%d",
            &ip_address[0], &ip_address[1], &ip_address[2], &ip_address[3],
            &port[0], &port[1]);
        if (i == 6) {
            /*
             * We have a winner!
             */
            *ftp_port = ((port[0] & 0xFF)<<8) | (port[1] & 0xFF);
            *ftp_ip = g_htonl((ip_address[0] << 24) | (ip_address[1] <<16) | (ip_address[2] <<8) | ip_address[3]);
            *pasv_offset = (guint32)(p - args);
            *ftp_port_len = (port[0] < 10 ? 1 : (port[0] < 100 ? 2 : 3 )) + 1 +
                            (port[1] < 10 ? 1 : (port[1] < 100 ? 2 : 3 ));
            *ftp_ip_len = (ip_address[0] < 10 ? 1 : (ip_address[0] < 100 ? 2 : 3)) + 1 +
                          (ip_address[1] < 10 ? 1 : (ip_address[1] < 100 ? 2 : 3)) + 1 +
                          (ip_address[2] < 10 ? 1 : (ip_address[2] < 100 ? 2 : 3)) + 1 +
                          (ip_address[3] < 10 ? 1 : (ip_address[3] < 100 ? 2 : 3));
            ret = TRUE;
            break;
        }

        /*
         * Well, that didn't work.  Skip the first number we found,
         * and keep trying.
         */
        while ((c = *p) != '\0' && isdigit(c))
            p++;
    }

    return ret;
}

static gboolean
isvalid_rfc2428_delimiter(const guchar c)
{
    /* RFC2428 sect. 2 states rules for a valid delimiter */
    static const gchar forbidden[] = {"0123456789abcdef.:"};
    if (c < 33 || c > 126)
        return FALSE;
    else if (strchr(forbidden, tolower(c)))
        return FALSE;
    else
        return TRUE;
}


/*
 * RFC2428 states...
 *
 *     AF Number   Protocol
 *     ---------   --------
 *     1           Internet Protocol, Version 4
 *     2           Internet Protocol, Version 6
 *
 *     AF Number   Address Format      Example
 *     ---------   --------------      -------
 *     1           dotted decimal      132.235.1.2
 *     2           IPv6 string         1080::8:800:200C:417A
 *                 representations
 *                 defined in
 *
 *     The following are sample EPRT commands:
 *          EPRT |1|132.235.1.2|6275|
 *          EPRT |2|1080::8:800:200C:417A|5282|
 *
 *     The first command specifies that the server should use IPv4 to open a
 *     data connection to the host "132.235.1.2" on TCP port 6275.  The
 *     second command specifies that the server should use the IPv6 network
 *     protocol and the network address "1080::8:800:200C:417A" to open a
 *     TCP data connection on port 5282.
 *
 * ... which means in fact that RFC2428 is capable to handle both,
 * IPv4 and IPv6 so we have to care about the address family and properly
 * act depending on it.
 *
 */
static gboolean
parse_eprt_request(const guchar* line, gint linelen, guint32 *eprt_af,
        guint32 *eprt_ip, guint16 *eprt_ipv6, guint16 *ftp_port,
        guint32 *eprt_ip_len, guint32 *ftp_port_len)
{
    gint      delimiters_seen = 0;
    gchar     delimiter;
    gint      fieldlen;
    gchar    *field;
    gint      n;
    gint      lastn;
    char     *args, *p;
    gboolean  ret = TRUE;


    /* line contains the EPRT parameters, we need at least the 4 delimiters */
    if (!line || linelen<4)
        return FALSE;

    /* Copy the rest of the line into a null-terminated buffer. */
    args = wmem_strndup(wmem_packet_scope(), line, linelen);
    p = args;

    /*
     * RFC2428 sect. 2 states ...
     *
     *     The EPRT command keyword MUST be followed by a single space (ASCII
     *     32). Following the space, a delimiter character (<d>) MUST be
     *     specified.
     *
     * ... the preceding <space> is already stripped so we know that the first
     * character must be the delimiter and has just to be checked to be valid.
     */
    if (!isvalid_rfc2428_delimiter(*p))
        return FALSE;  /* EPRT command does not follow a vaild delimiter;
                        * malformed EPRT command - immediate escape */

    delimiter = *p;
    /* Validate that the delimiter occurs 4 times in the string */
    for (n = 0; n < linelen; n++) {
        if (*(p+n) == delimiter)
            delimiters_seen++;
    }
    if (delimiters_seen != 4)
        return FALSE; /* delimiter doesn't occur 4 times
                       * probably no EPRT request - immediate escape */

    /* we know that the first character is a delimiter... */
    delimiters_seen = 1;
    lastn = 0;
    /* ... so we can start searching from the 2nd onwards */
    for (n=1; n < linelen; n++) {

        if (*(p+n) != delimiter)
            continue;

        /* we found a delimiter */
        delimiters_seen++;

        fieldlen = n - lastn - 1;
        if (fieldlen<=0)
            return FALSE; /* all fields must have data in them */
        field =  p + lastn + 1;

        if (delimiters_seen == 2) {     /* end of address family field */
            gchar *af_str;
            af_str = wmem_strndup(wmem_packet_scope(), field, fieldlen);
            *eprt_af = atoi(af_str);
        }
        else if (delimiters_seen == 3) {/* end of IP address field */
            gchar *ip_str;
            ip_str = wmem_strndup(wmem_packet_scope(), field, fieldlen);

            if (*eprt_af == EPRT_AF_IPv4) {
                if (inet_pton(AF_INET, ip_str, eprt_ip) > 0)
                   ret = TRUE;
                else
                   ret = FALSE;
            }
            else if (*eprt_af == EPRT_AF_IPv6) {
                if (inet_pton(AF_INET6, ip_str, eprt_ipv6) > 0)
                   ret = TRUE;
                else
                   ret = FALSE;
            }
            else
                return FALSE; /* invalid/unknown address family */

            *eprt_ip_len = fieldlen;
        }
        else if (delimiters_seen == 4) {/* end of port field */
            gchar *pt_str;
            pt_str = wmem_strndup(wmem_packet_scope(), field, fieldlen);

            *ftp_port = atoi(pt_str);
            *ftp_port_len = fieldlen;
        }

        lastn = n;
    }

    return ret;
}

/*
 * RFC2428 states ....
 *
 *   The first two fields contained in the parenthesis MUST be blank. The
 *   third field MUST be the string representation of the TCP port number
 *   on which the server is listening for a data connection.
 *
 *   The network protocol used by the data connection will be the same network
 *   protocol used by the control connection. In addition, the network
 *   address used to establish the data connection will be the same
 *   network address used for the control connection.
 *
 *   An example response    string follows:
 *
 *       Entering Extended Passive Mode (|||6446|)
 *
 * ... which in fact means that again both address families IPv4 and IPv6
 * are supported. But gladly it's not necessary to parse because it doesn't
 * occur in EPSV responses. We can leverage ftp_ip_address which is
 * protocol independent and already set.
 *
 */
static gboolean
parse_extended_pasv_response(const guchar *line, gint linelen, guint16 *ftp_port,
        guint *pasv_offset, guint *ftp_port_len)
{
    gint       n;
    gchar     *args;
    gchar     *p;
    gchar     *e;
    guchar     c;
    gboolean   ret             = FALSE;
    gboolean   delimiters_seen = FALSE;

    /*
     * Copy the rest of the line into a null-terminated buffer.
     */
    args = wmem_strndup(wmem_packet_scope(), line, linelen);
    p = args;

    /*
     * Look for ( <d> <d> <d>
       (Try to cope with '(' in description)
     */
    for (; !delimiters_seen;) {
        guchar delimiter = '\0';
        while ((c = *p) != '\0' && (c != '('))
            p++;

        if (*p == '\0') {
            return FALSE;
        }

        /* Skip '(' */
        p++;

        /* Make sure same delimiter is used 3 times */
        for (n=0; n<3; n++) {
            if ((c = *p) != '\0') {
                if (delimiter == '\0' && isvalid_rfc2428_delimiter(c)) {
                    delimiter = c;
                }
                if (c != delimiter) {
                    break;
                }
            p++;
            }
            else {
                break;
            }
        }
        delimiters_seen = TRUE;
    }

    /*
     * Should now be at digits.
     */
    if (*p != '\0') {
        /*
         * We didn't run out of text without finding anything.
         */
        *ftp_port = atoi(p);
        *pasv_offset = (guint32)(p - args);

        ret = TRUE;

        /* get port string length */
        if ((e=strchr(p,')')) == NULL) {
            ret = FALSE;
        }
        else {
            *ftp_port_len = (guint)(--e - p);
        }
    }

    return ret;
}


static void
dissect_ftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    gboolean        is_request;
    proto_tree     *ftp_tree          = NULL;
    proto_tree     *reqresp_tree      = NULL;
    proto_item     *ti, *hidden_item;
    gint            offset;
    const guchar   *line;
    guint32         code;
    gchar           code_str[4];
    gboolean        is_port_request   = FALSE;
    gboolean        is_eprt_request   = FALSE;
    gboolean        is_pasv_response  = FALSE;
    gboolean        is_epasv_response = FALSE;
    gint            next_offset;
    int             linelen;
    int             tokenlen          = 0;
    const guchar   *next_token;
    guint32         pasv_ip;
    guint32         pasv_offset;
    guint32         ftp_ip;
    guint32         ftp_ip_len;
    guint32         eprt_offset;
    guint32         eprt_af           = 0;
    guint32         eprt_ip;
    guint16         eprt_ipv6[8];
    guint32         eprt_ip_len       = 0;
    guint16         ftp_port;
    guint32         ftp_port_len;
    address         ftp_ip_address;
    gboolean        ftp_nat;
    conversation_t *conversation;

    ftp_ip_address = pinfo->src;

    if (pinfo->match_uint == pinfo->destport)
        is_request = TRUE;
    else
        is_request = FALSE;

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

    /*
     * Find the end of the first line.
     *
     * Note that "tvb_find_line_end()" will return a value that is
     * not longer than what's in the buffer, so the "tvb_get_ptr()"
     * call won't throw an exception.
     */
    linelen = tvb_find_line_end(tvb, 0, -1, &next_offset, FALSE);
    line    = tvb_get_ptr(tvb, 0, linelen);

    /*
     * Put the first line from the buffer into the summary
     * (but leave out the line terminator).
     */
    col_add_fstr(pinfo->cinfo, COL_INFO, "%s: %s",
        is_request ? "Request" : "Response",
        format_text(line, linelen));

    ti = proto_tree_add_item(tree, proto_ftp, tvb, 0, -1, ENC_NA);
    ftp_tree = proto_item_add_subtree(ti, ett_ftp);

    if (is_request) {
        hidden_item = proto_tree_add_boolean(ftp_tree,
                hf_ftp_request, tvb, 0, 0, TRUE);
        PROTO_ITEM_SET_HIDDEN(hidden_item);
        hidden_item = proto_tree_add_boolean(ftp_tree,
                hf_ftp_response, tvb, 0, 0, FALSE);
        PROTO_ITEM_SET_HIDDEN(hidden_item);
    } else {
        hidden_item = proto_tree_add_boolean(ftp_tree,
                hf_ftp_request, tvb, 0, 0, FALSE);
        PROTO_ITEM_SET_HIDDEN(hidden_item);
        hidden_item = proto_tree_add_boolean(ftp_tree,
                hf_ftp_response, tvb, 0, 0, TRUE);
        PROTO_ITEM_SET_HIDDEN(hidden_item);
    }

    /* Put the line into the protocol tree. */
    ti = proto_tree_add_text(ftp_tree, tvb, 0, next_offset, "%s",
            tvb_format_text(tvb, 0, next_offset));
    reqresp_tree = proto_item_add_subtree(ti, ett_ftp_reqresp);

    if (is_request) {
        /*
         * Extract the first token, and, if there is a first
         * token, add it as the request.
         */
        tokenlen = get_token_len(line, line + linelen, &next_token);
        if (tokenlen != 0) {
            proto_tree_add_item(reqresp_tree, hf_ftp_request_command,
                    tvb, 0, tokenlen, ENC_ASCII|ENC_NA);
            if (strncmp(line, "PORT", tokenlen) == 0)
                is_port_request = TRUE;
            /*
             * EPRT request command, as per RFC 2428
             */
            else if (strncmp(line, "EPRT", tokenlen) == 0)
                is_eprt_request = TRUE;
        }
    } else {
        /*
         * This is a response; the response code is 3 digits,
         * followed by a space or hyphen, possibly followed by
         * text.
         *
         * If the line doesn't start with 3 digits, it's part of
         * a continuation.
         *
         * XXX - keep track of state in the first pass, and
         * treat non-continuation lines not beginning with digits
         * as errors?
         */
        if (linelen >= 3 && isdigit(line[0]) && isdigit(line[1])
            && isdigit(line[2])) {
            /*
             * One-line reply, or first or last line
             * of a multi-line reply.
             */
            tvb_get_nstringz0(tvb, 0, sizeof(code_str), code_str);
            code = (guint32)strtoul(code_str, NULL, 10);

            proto_tree_add_uint(reqresp_tree,
                    hf_ftp_response_code, tvb, 0, 3, code);

            /*
             * See if it's a passive-mode response.
             *
             * XXX - does anybody do FOOBAR, as per RFC
             * 1639, or has that been supplanted by RFC 2428?
             */
            if (code == 227)
                is_pasv_response = TRUE;

            /*
             * Responses to EPSV command, as per RFC 2428
             */
            if (code == 229)
                is_epasv_response = TRUE;

            /*
             * Skip the 3 digits and, if present, the
             * space or hyphen.
             */
            if (linelen >= 4)
                next_token = line + 4;
            else
                next_token = line + linelen;
        } else {
            /*
             * Line doesn't start with 3 digits; assume it's
             * a line in the middle of a multi-line reply.
             */
            next_token = line;
        }
    }

    offset   = (gint) (next_token - line);
    linelen -= (int) (next_token - line);
    line     = next_token;

    /*
     * Add the rest of the first line as request or
     * reply data.
     */
    if (linelen != 0) {
        if (is_request) {
            proto_tree_add_item(reqresp_tree,
                    hf_ftp_request_arg, tvb, offset,
                    linelen, ENC_ASCII|ENC_NA);
        } else {
            proto_tree_add_item(reqresp_tree,
                    hf_ftp_response_arg, tvb, offset,
                    linelen, ENC_ASCII|ENC_NA);
        }
    }
    offset = next_offset;

    /*
     * If this is a PORT request or a PASV response, handle it.
     */
    if (is_port_request) {
        if (parse_port_pasv(line, linelen, &ftp_ip, &ftp_port, &pasv_offset, &ftp_ip_len, &ftp_port_len)) {
            proto_tree_add_ipv4(reqresp_tree, hf_ftp_active_ip,
                    tvb, pasv_offset + (tokenlen+1) , ftp_ip_len, ftp_ip);
            proto_tree_add_uint(reqresp_tree, hf_ftp_active_port,
                    tvb, pasv_offset + 1 + (tokenlen+1) + ftp_ip_len, ftp_port_len, ftp_port);
            SET_ADDRESS(&ftp_ip_address, AT_IPv4, 4, (const guint8 *)&ftp_ip);
            ftp_nat = !ADDRESSES_EQUAL(&pinfo->src, &ftp_ip_address);
            if (ftp_nat) {
                proto_tree_add_boolean(reqresp_tree, hf_ftp_active_nat,
                        tvb, 0, 0, ftp_nat);
            }
        }
    }

    if (is_pasv_response) {
        if (linelen != 0) {
            /*
             * This frame contains a PASV response; set up a
             * conversation for the data.
             */
            if (parse_port_pasv(line, linelen, &pasv_ip, &ftp_port, &pasv_offset, &ftp_ip_len, &ftp_port_len)) {
                proto_tree_add_ipv4(reqresp_tree, hf_ftp_pasv_ip,
                        tvb, pasv_offset + 4, ftp_ip_len, pasv_ip);
                proto_tree_add_uint(reqresp_tree, hf_ftp_pasv_port,
                        tvb, pasv_offset + 4 + 1 + ftp_ip_len, ftp_port_len, ftp_port);
                SET_ADDRESS(&ftp_ip_address, AT_IPv4, 4,
                    (const guint8 *)&pasv_ip);
                ftp_nat = !ADDRESSES_EQUAL(&pinfo->src, &ftp_ip_address);
                if (ftp_nat) {
                    proto_tree_add_boolean(reqresp_tree, hf_ftp_pasv_nat,
                            tvb, 0, 0, ftp_nat);
                }

                /*
                 * We use "ftp_ip_address", so that if
                 * we're NAT'd we look for the un-NAT'd
                 * connection.
                 *
                 * XXX - should this call to
                 * "find_conversation()" just use
                 * "ftp_ip_address" and "server_port", and
                 * wildcard everything else?
                 */
                conversation = find_conversation(pinfo->fd->num, &ftp_ip_address,
                    &pinfo->dst, PT_TCP, ftp_port, 0,
                    NO_PORT_B);
                if (conversation == NULL) {
                    /*
                     * XXX - should this call to "conversation_new()"
                     * just use "ftp_ip_address" and "server_port",
                     * and wildcard everything else?
                     *
                     * XXX - what if we did find a conversation?  As
                     * we create it only on the first pass through the
                     * packets, if we find one, it's presumably an
                     * unrelated conversation.  Should we remove the
                     * old one from the hash table and put this one in
                     * its place?  Can the conversation code handle
                     * conversations not in the hash table?  Or should
                     * we make conversations support start and end
                     * frames, as circuits do, and treat this as an
                     * indication that one conversation was closed and
                     * a new one was opened?
                     */
                    conversation = conversation_new(
                        pinfo->fd->num, &ftp_ip_address, &pinfo->dst,
                        PT_TCP, ftp_port, 0, NO_PORT2);
                    conversation_set_dissector(conversation, ftpdata_handle);
                }
            }
        }
    }

    if (is_eprt_request) {
        /*
         * RFC2428 - sect. 2
         * This frame contains a EPRT request; let's dissect it and set up a
         * conversation for the data connection.
         */
        if (parse_eprt_request(line, linelen,
                    &eprt_af, &eprt_ip, eprt_ipv6, &ftp_port,
                    &eprt_ip_len, &ftp_port_len)) {

            /* since parse_eprt_request() returned TRUE,
               we know that we have a valid address family */
            eprt_offset = tokenlen + 1 + 1;  /* token, space, 1st delimiter */
            proto_tree_add_uint(reqresp_tree, hf_ftp_eprt_af, tvb,
                    eprt_offset, 1, eprt_af);
            eprt_offset += 1 + 1; /* addr family, 2nd delimiter */

            if (eprt_af == EPRT_AF_IPv4) {
                proto_tree_add_ipv4(reqresp_tree, hf_ftp_eprt_ip,
                        tvb, eprt_offset, eprt_ip_len, eprt_ip);
                SET_ADDRESS(&ftp_ip_address, AT_IPv4, 4,
                        (const guint8 *)&eprt_ip);
            }
            else if (eprt_af == EPRT_AF_IPv6) {
                proto_tree_add_ipv6(reqresp_tree, hf_ftp_eprt_ipv6,
                        tvb, eprt_offset, eprt_ip_len, (const guint8 *)eprt_ipv6);
                SET_ADDRESS(&ftp_ip_address, AT_IPv6, 16,
                        (const guint8 *)&eprt_ipv6);
            }
            eprt_offset += eprt_ip_len + 1; /* addr, 3rd delimiter */

            proto_tree_add_uint(reqresp_tree, hf_ftp_eprt_port,
                    tvb, eprt_offset, ftp_port_len, ftp_port);

            /* Find/create conversation for data */
            conversation = find_conversation(pinfo->fd->num,
                    &pinfo->src, &ftp_ip_address,
                    PT_TCP, ftp_port, 0, NO_PORT_B);
            if (conversation == NULL) {
                conversation = conversation_new(
                        pinfo->fd->num, &pinfo->src, &ftp_ip_address,
                        PT_TCP, ftp_port, 0, NO_PORT2);
                conversation_set_dissector(conversation,
                        ftpdata_handle);
            }
        }
        else {
            proto_item *item;
            item = proto_tree_add_text(reqresp_tree,
                    tvb, offset - linelen - 1, linelen, "Invalid EPRT arguments");
            expert_add_info(pinfo, item, &ei_ftp_eprt_args_invalid);
        }
    }

    if (is_epasv_response) {
        if (linelen != 0) {
            proto_item *addr_it;
            /*
             * RFC2428 - sect. 3
             * This frame contains an  EPSV response; set up a
             * conversation for the data.
             */
            if (parse_extended_pasv_response(line, linelen,
                        &ftp_port, &pasv_offset, &ftp_port_len)) {
                /* Add IP address and port number to tree */

                if (ftp_ip_address.type == AT_IPv4) {
                    guint32 addr;
                    memcpy(&addr, ftp_ip_address.data, 4);
                    addr_it = proto_tree_add_ipv4(reqresp_tree,
                            hf_ftp_epsv_ip, tvb, 0, 0, addr);
                    PROTO_ITEM_SET_GENERATED(addr_it);
                }
                else if (ftp_ip_address.type == AT_IPv6) {
                    addr_it = proto_tree_add_ipv6(reqresp_tree,
                            hf_ftp_epsv_ipv6, tvb, 0, 0,
                            (guint8*)ftp_ip_address.data);
                    PROTO_ITEM_SET_GENERATED(addr_it);
                }

                proto_tree_add_uint(reqresp_tree,
                        hf_ftp_epsv_port, tvb, pasv_offset + 4,
                        ftp_port_len, ftp_port);

                /* Find/create conversation for data */
                conversation = find_conversation(pinfo->fd->num, &ftp_ip_address,
                                                 &pinfo->dst, PT_TCP, ftp_port, 0,
                                                 NO_PORT_B);
                if (conversation == NULL) {
                    conversation = conversation_new(
                        pinfo->fd->num, &ftp_ip_address, &pinfo->dst,
                        PT_TCP, ftp_port, 0, NO_PORT2);
                    conversation_set_dissector(conversation,
                        ftpdata_handle);
                }
            }
            else {
                proto_item *item;
                item = proto_tree_add_text(reqresp_tree,
                        tvb, offset - linelen - 1, linelen, "Invalid EPSV arguments");
                expert_add_info(pinfo, item, &ei_ftp_epsv_args_invalid);
            }
        }
    }

    /*
     * Show the rest of the request or response as text,
     * a line at a time.
     * XXX - only if there's a continuation indicator?
     */
    while (tvb_offset_exists(tvb, offset)) {
        /*
         * Find the end of the line.
         */
        tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);

        /*
         * Put this line.
         */
        proto_tree_add_text(ftp_tree, tvb, offset,
                next_offset - offset, "%s",
                tvb_format_text(tvb, offset, next_offset - offset));
        offset = next_offset;
    }
}

static void
dissect_ftpdata(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    proto_item *ti;
    int         data_length;
    gboolean    is_text = TRUE;
    gint        check_chars, i;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "FTP-DATA");

    col_add_fstr(pinfo->cinfo, COL_INFO, "FTP Data: %u bytes",
        tvb_reported_length(tvb));

    data_length = tvb_length(tvb);

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

    /* Check the first few chars to see whether it looks like a text file or not */
    check_chars = MIN(10, data_length);
    for (i=0; i < check_chars; i++) {
        if (!isprint(tvb_get_guint8(tvb, i))) {
            is_text = FALSE;
            break;
        }
    }

    if (is_text) {
        /* Show as string, but don't format more text than will be displayed */
        proto_item_append_text(ti, " (%s)", tvb_format_text(tvb, 0, MIN(data_length, ITEM_LABEL_LENGTH)));
    }
    else {
        /* Assume binary, just show the number of bytes */
        proto_item_append_text(ti, " (%u bytes data)", data_length);
    }
}

void
proto_register_ftp(void)
{
    static hf_register_info hf[] = {
        { &hf_ftp_response,
          { "Response",           "ftp.response",
            FT_BOOLEAN, BASE_NONE, NULL, 0x0,
            "TRUE if FTP response", HFILL }},

        { &hf_ftp_request,
          { "Request",            "ftp.request",
            FT_BOOLEAN, BASE_NONE, NULL, 0x0,
            "TRUE if FTP request", HFILL }},

        { &hf_ftp_request_command,
          { "Request command",    "ftp.request.command",
            FT_STRING,  BASE_NONE, NULL, 0x0,
            NULL, HFILL }},

        { &hf_ftp_request_arg,
          { "Request arg",        "ftp.request.arg",
            FT_STRING,  BASE_NONE, NULL, 0x0,
            NULL, HFILL }},

        { &hf_ftp_response_code,
          { "Response code",      "ftp.response.code",
            FT_UINT32,   BASE_DEC|BASE_EXT_STRING, &response_table_ext, 0x0,
            NULL, HFILL }},

        { &hf_ftp_response_arg,
          { "Response arg",      "ftp.response.arg",
            FT_STRING,  BASE_NONE, NULL, 0x0,
            NULL, HFILL }},

        { &hf_ftp_pasv_ip,
          { "Passive IP address", "ftp.passive.ip",
            FT_IPv4, BASE_NONE, NULL,0x0,
            "Passive IP address (check NAT)", HFILL}},

        { &hf_ftp_pasv_port,
          { "Passive port", "ftp.passive.port",
            FT_UINT16, BASE_DEC, NULL,0x0,
            "Passive FTP server port", HFILL }},

        { &hf_ftp_pasv_nat,
          {"Passive IP NAT", "ftp.passive.nat",
           FT_BOOLEAN, BASE_NONE, NULL, 0x0,
           "NAT is active SIP and passive IP different", HFILL }},

        { &hf_ftp_active_ip,
          { "Active IP address", "ftp.active.cip",
            FT_IPv4, BASE_NONE, NULL, 0x0,
            "Active FTP client IP address", HFILL }},

        { &hf_ftp_active_port,
          {"Active port", "ftp.active.port",
           FT_UINT16, BASE_DEC, NULL, 0x0,
           "Active FTP client port", HFILL }},

        { &hf_ftp_active_nat,
          { "Active IP NAT", "ftp.active.nat",
            FT_BOOLEAN, BASE_NONE, NULL, 0x0,
            "NAT is active", HFILL}},

        { &hf_ftp_eprt_af,
          { "Extended active address family", "ftp.eprt.af",
            FT_UINT8, BASE_DEC, VALS(eprt_af_vals), 0,
            NULL, HFILL }},

        { &hf_ftp_eprt_ip,
          { "Extended active IP address", "ftp.eprt.ip",
            FT_IPv4, BASE_NONE, NULL, 0,
            "Extended active FTP client IPv4 address", HFILL }},

        { &hf_ftp_eprt_ipv6,
          { "Extended active IPv6 address", "ftp.eprt.ipv6",
            FT_IPv6, BASE_NONE, NULL, 0,
            "Extended active FTP client IPv6 address", HFILL }},

        { &hf_ftp_eprt_port,
          { "Extended active port", "ftp.eprt.port",
            FT_UINT16, BASE_DEC, NULL, 0,
            "Extended active FTP client listener port", HFILL }},

        { &hf_ftp_epsv_ip,
          { "Extended passive IPv4 address", "ftp.epsv.ip",
            FT_IPv4, BASE_NONE, NULL, 0,
            "Extended passive FTP server IPv4 address", HFILL }},

        { &hf_ftp_epsv_ipv6,
          { "Extended passive IPv6 address", "ftp.epsv.ipv6",
            FT_IPv6, BASE_NONE, NULL, 0,
            "Extended passive FTP server IPv6 address", HFILL }},

        { &hf_ftp_epsv_port,
          { "Extended passive port", "ftp.epsv.port",
            FT_UINT16, BASE_DEC, NULL, 0,
            "Extended passive FTP server port", HFILL }}

    };
    static gint *ett[] = {
        &ett_ftp,
        &ett_ftp_reqresp
    };

    static ei_register_info ei[] = {
        { &ei_ftp_eprt_args_invalid, { "ftp.eprt.args_invalid", PI_MALFORMED, PI_WARN, "EPRT arguments must have the form: |<family>|<addr>|<port>|", EXPFILL }},
        { &ei_ftp_epsv_args_invalid, { "ftp.epsv.args_invalid", PI_MALFORMED, PI_WARN, "EPSV arguments must have the form (|||<port>|)", EXPFILL }},
    };

    expert_module_t* expert_ftp;

    proto_ftp = proto_register_protocol("File Transfer Protocol (FTP)", "FTP", "ftp");

    register_dissector("ftp", dissect_ftp, proto_ftp);
    proto_ftp_data = proto_register_protocol("FTP Data", "FTP-DATA", "ftp-data");
    register_dissector("ftp-data", dissect_ftpdata, proto_ftp_data);
    proto_register_field_array(proto_ftp, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
    expert_ftp = expert_register_protocol(proto_ftp);
    expert_register_field_array(expert_ftp, ei, array_length(ei));
}

void
proto_reg_handoff_ftp(void)
{
    dissector_handle_t ftp_handle;

    ftpdata_handle = find_dissector("ftp-data");
    dissector_add_uint("tcp.port", TCP_PORT_FTPDATA, ftpdata_handle);
    ftp_handle = find_dissector("ftp");
    dissector_add_uint("tcp.port", TCP_PORT_FTP, ftp_handle);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 4
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=4 tabstop=4 expandtab:
 * :indentSize=4:tabSize=4:noTabs=true:
 */