/*
 * Version 0.01
 * 29.09.02
 *
 */
/*
 * 
 * Traf thief
 *
 * Tested on Apache 2.0.42
 * Works only on Apache 2.x
 *
 * Outline:
 * - Redirects each %d request to spicified URL.
 * 
 *
 * Module Directives:  See README file or HTML documentation.
 * 
 * ChangeLog: See Changelog for details
 *
 *		Homepage	http://web.god.net.ru/projects/mod_traf_thief/
 *
 *		Latest sources  http://web.god.net.ru/projects/mod_traf_thief/dist/
 *
 *		Maintainer:
 *				Yuri
 *				gr_yuri@mail.ru
 *
 *		Greets:	
 *				tf8 (silent@zolo.freelsd.net),delta(spn@g0v.ru) -- for C help
 *				Alex Tatubalin (http://lexa.ru) -- mod_uid2.c was the best helper :)
 *
 *
 */

#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "apr_strings.h"
#include "apr_lib.h"
#include "apr_general.h"
#include "util_filter.h"
#include "apr_buckets.h"
#include "http_request.h"

#define OFF		1
#define ON		2

#define DEFAULT_PERIOD 1000

module AP_MODULE_DECLARE_DATA traf_thief_module;

#define OVER(field) (over->field?over->field:base->field)

typedef struct 
{
  int enabled;
  char *url;
  int period;
} thief_serv_rec;

static int make_thief(request_rec *r);
static const char *set_thief_enable(cmd_parms *cmd, void *mconfig, int arg);
static const char *set_thief_period(cmd_parms *cmd, void *mconfig, const char *arg);
static const char *set_thief_url(cmd_parms *cmd, void *mconfig, const char *arg);
static void *make_thief_dir(apr_pool_t *p, char *d);
static void *merge_thief_dir(apr_pool_t *p, void *basev, void *overridesv);
static void register_hooks(apr_pool_t *p);


static const command_rec thief_cmds[] = {
    AP_INIT_FLAG("ThiefEnable", set_thief_enable, NULL, ACCESS_CONF | RSRC_CONF,
		  "Enable flag"),
    AP_INIT_TAKE1("ThiefPeriod", set_thief_period, NULL, ACCESS_CONF| RSRC_CONF,
		  "Set period flag"),
    AP_INIT_TAKE1("ThiefURL", set_thief_url, NULL, ACCESS_CONF| RSRC_CONF,
		  "Set traffic URL"),
	{NULL}
};

static int make_thief(request_rec *r)
{
	thief_serv_rec *tcfg = ap_get_module_config(r->per_dir_config,
						&traf_thief_module);
	const char *count;
	char *req_host;

	
	if (tcfg->enabled == ON) {
        req_host = apr_pstrdup(r->pool, r->server->server_hostname);
		srandom(time(NULL));
		if ((random() % tcfg->period + 1) == tcfg->period) {
			apr_table_addn(r->headers_out, "Location",tcfg->url); 
			return HTTP_MOVED_PERMANENTLY;
		}
	}
	return DECLINED;
}


static const char *set_thief_enable(cmd_parms *cmd, void *mconfig, int arg)
{
    thief_serv_rec *tcfg = mconfig;
    tcfg->enabled = arg?ON:OFF;
    return NULL;
}

static const char *set_thief_period(cmd_parms *cmd, void *mconfig, const char *arg)
{
	int i,check = 1;
    thief_serv_rec *tcfg = mconfig;
	for(i=0;i < strlen(arg);i++)
		if (!apr_isdigit(arg[i])) {
			check = 0;
			break;
		}

    tcfg->period = check ? atoi(arg) : DEFAULT_PERIOD;
    return NULL;
}

static const char *set_thief_url(cmd_parms *cmd, void *mconfig, const char *arg)
{
	const char *url = arg;
	thief_serv_rec *tcfg = mconfig;
	
	if (!url)
		return "Thereis no URL to thief";
	if (!ap_is_url(url))
		return "Thief URL - non-URL";

	tcfg->url = apr_pstrdup(cmd->pool, url);
	
    return NULL;
}

static void *make_thief_dir(apr_pool_t *p, char *d)
{
    thief_serv_rec *tcfg = (thief_serv_rec *)apr_pcalloc	(p,	sizeof(thief_serv_rec));
	tcfg->enabled = OFF;
	tcfg->period = 0;
	
    return tcfg;
}

static void * 
merge_thief_dir (apr_pool_t *p, void *basev, void *overridesv)
{
    thief_serv_rec *base = (thief_serv_rec *)basev;
    thief_serv_rec *over = (thief_serv_rec *)overridesv;
    thief_serv_rec *tcfg;
    tcfg = (thief_serv_rec *) apr_pcalloc(p, sizeof(thief_serv_rec));
    tcfg->enabled	= OVER(enabled);
	tcfg->url	= OVER(url);
	tcfg->period	= OVER(period);
    return tcfg;
}

static void register_hooks(apr_pool_t *p)
{
    ap_hook_fixups(make_thief, NULL, NULL, APR_HOOK_MIDDLE);
}

module AP_MODULE_DECLARE_DATA traf_thief_module = { 
    STANDARD20_MODULE_STUFF, 
    make_thief_dir, /* dir config creater */ 
    merge_thief_dir, /* dir merger --- default is to override */ 
    NULL, /* server config */ 
    NULL, /* merge server config */ 
    thief_cmds, /* command table */ 
    register_hooks /* register_handlers */ 
};