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/* packet-http-urlencoded.c
 * Routines for dissection of HTTP urlecncoded form, based on packet-text-media.c (C) Olivier Biot, 2004.
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * 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.
 */

#define NEW_PROTO_TREE_API

#include "config.h"

#include <epan/packet.h>
#include <wsutil/str_util.h>

#include "packet-http.h"

void proto_register_http_urlencoded(void);
void proto_reg_handoff_http_urlencoded(void);

static dissector_handle_t form_urlencoded_handle;

static header_field_info *hfi_urlencoded = NULL;

#define URLENCODED_HFI_INIT HFI_INIT(proto_urlencoded)

static header_field_info hfi_form_key URLENCODED_HFI_INIT =
        { "Key", "urlencoded-form.key", FT_STRINGZ, BASE_NONE, NULL, 0x0, NULL, HFILL };

static header_field_info hfi_form_value URLENCODED_HFI_INIT =
        { "Value", "urlencoded-form.value", FT_STRINGZ, BASE_NONE, NULL, 0x0, NULL, HFILL };

static gint ett_form_urlencoded = -1;
static gint ett_form_keyvalue = -1;

static int
get_form_key_value(tvbuff_t *tvb, char **ptr, int offset, char stop)
{
        const int orig_offset = offset;
        char *tmp;
        int len;

        len = 0;
        while (tvb_reported_length_remaining(tvb, offset) > 0) {
                guint8 ch;

                ch = tvb_get_guint8(tvb, offset);
                if (!ch)
                        return -1;
                if (ch == stop)
                        break;
                if (ch == '%') {
                        offset++;
                        ch = tvb_get_guint8(tvb, offset);
                        if (ws_xton(ch) == -1)
                                return -1;

                        offset++;
                        ch = tvb_get_guint8(tvb, offset);
                        if (ws_xton(ch) == -1)
                                return -1;
                }

                len++;
                offset++;
        }

        *ptr = tmp = (char*)wmem_alloc(wmem_packet_scope(), len + 1);
        tmp[len] = '\0';

        len = 0;
        offset = orig_offset;
        while (tvb_reported_length_remaining(tvb, offset) > 0) {
                guint8 ch;

                ch = tvb_get_guint8(tvb, offset);
                if (!ch)
                        return -1;
                if (ch == stop)
                        break;

                if (ch == '%') {
                        guint8 ch1, ch2;

                        offset++;
                        ch1 = tvb_get_guint8(tvb, offset);

                        offset++;
                        ch2 = tvb_get_guint8(tvb, offset);

                        tmp[len] = ws_xton(ch1) << 4 | ws_xton(ch2);

                } else if (ch == '+')
                        tmp[len] = ' ';
                else
                        tmp[len] = ch;

                len++;
                offset++;
        }

        return offset;
}


static int
dissect_form_urlencoded(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
        proto_tree      *url_tree;
        proto_tree      *sub;
        proto_item      *ti;
        gint            offset = 0, next_offset;
        const char      *data_name;
        http_message_info_t *message_info;

        data_name = pinfo->match_string;
        if (! (data_name && data_name[0])) {
                /*
                 * No information from "match_string"
                 */
                message_info = (http_message_info_t *)data;
                if (message_info == NULL) {
                        /*
                         * No information from dissector data
                         */
                        data_name = NULL;
                } else {
                        data_name = message_info->media_str;
                        if (! (data_name && data_name[0])) {
                                /*
                                 * No information from dissector data
                                 */
                                data_name = NULL;
                        }
                }
        }

        if (data_name)
                col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "(%s)", data_name);

        ti = proto_tree_add_item(tree, hfi_urlencoded, tvb, 0, -1, ENC_NA);
        if (data_name)
                proto_item_append_text(ti, ": %s", data_name);
        url_tree = proto_item_add_subtree(ti, ett_form_urlencoded);

        while (tvb_reported_length_remaining(tvb, offset) > 0) {
                const int start_offset = offset;
                char *key, *value;

                sub = proto_tree_add_subtree(url_tree, tvb, offset, 0, ett_form_keyvalue, &ti, "Form item");

                next_offset = get_form_key_value(tvb, &key, offset, '=');
                if (next_offset == -1)
                        break;
                proto_tree_add_string(sub, &hfi_form_key, tvb, offset, next_offset - offset, key);
                proto_item_append_text(sub, ": \"%s\"", key);

                offset = next_offset+1;

                next_offset = get_form_key_value(tvb, &value, offset, '&');
                if (next_offset == -1)
                        break;
                proto_tree_add_string(sub, &hfi_form_value, tvb, offset, next_offset - offset, value);
                proto_item_append_text(sub, " = \"%s\"", value);

                offset = next_offset+1;

                proto_item_set_len(ti, offset - start_offset);
        }

        return tvb_captured_length(tvb);
}

void
proto_register_http_urlencoded(void)
{
#ifndef HAVE_HFI_SECTION_INIT
        static header_field_info *hfi[] = {
                &hfi_form_key,
                &hfi_form_value,
        };
#endif

        static gint *ett[] = {
                &ett_form_urlencoded,
                &ett_form_keyvalue
        };

        int proto_urlencoded;

        proto_urlencoded = proto_register_protocol("HTML Form URL Encoded", "URL Encoded Form Data", "urlencoded-form");
        hfi_urlencoded = proto_registrar_get_nth(proto_urlencoded);

        form_urlencoded_handle = register_dissector("urlencoded-form", dissect_form_urlencoded, proto_urlencoded);

        proto_register_fields(proto_urlencoded, hfi, array_length(hfi));
        proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_http_urlencoded(void)
{
        dissector_add_string("media_type", "application/x-www-form-urlencoded", form_urlencoded_handle);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */