[irc/rqf/shadowircd.git] / extensions / ip_cloaking.c

/* $Id: ip_cloaking.c 3526 2007-07-06 07:56:14Z nenolod $ */

#include "stdinc.h"
#include "modules.h"
#include "hook.h"
#include "client.h"
#include "ircd.h"
#include "send.h"
#include "s_conf.h"
#include "s_user.h"
#include "s_serv.h"
#include "tools.h"
#include "numeric.h"

/* if you're modifying this module, you'll probably to change this */
#define KEY 0x13748cfa

static int
_modinit(void)
{
	/* add the usermode to the available slot */
	user_modes['h'] = find_umode_slot();
	construct_umodebuf();

	return 0;
}

static void
_moddeinit(void)
{
	/* disable the umode and remove it from the available list */
	user_modes['h'] = 0;
	construct_umodebuf();
}

static void check_umode_change(void *data);
static void check_new_user(void *data);
mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
	{ "umode_changed", (hookfn) check_umode_change },
	{ "new_local_user", (hookfn) check_new_user },
	{ NULL, NULL }
};

DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
			ip_cloaking_hfnlist, "$Revision: 3526 $");

static void
distribute_hostchange(struct Client *client)
{
	if (irccmp(client->host, client->orighost))
		sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :is now your hidden host",
			client->host);
	else
		sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :hostname reset",
			client->host);

	sendto_server(NULL, NULL,
		CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
		use_id(&me), use_id(client), client->host);
	sendto_server(NULL, NULL,
		CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
		use_id(&me), use_id(client), client->host);
	sendto_server(NULL, NULL,
		NOCAPS, CAP_TS6, ":%s ENCAP * CHGHOST %s :%s",
		me.name, client->name, client->host);
	if (irccmp(client->host, client->orighost))
		SetDynSpoof(client);
	else
		ClearDynSpoof(client);
}

#define Nval 0x8c3a48ac
#define HOSTLEN 63
#define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */

static inline unsigned int
get_string_entropy(const char *inbuf)
{
	unsigned int accum = 1;

	while(*inbuf != '\0')
		accum += *inbuf++;

	return accum;
}

/* calls get_string_entropy() and toasts it against INITDATA */
static inline unsigned int
get_string_weighted_entropy(const char *inbuf)
{
	static int base_entropy = 0;
        unsigned int accum = get_string_entropy(inbuf);

	/* initialize the algorithm if it is not yet ready */
	if (base_entropy == 0)
		base_entropy = get_string_entropy(INITDATA);

        return (Nval * accum) ^ base_entropy;
}

static void
do_host_cloak_ip(const char *inbuf, char *outbuf)
{
	char *tptr;
	unsigned int accum = get_string_weighted_entropy(inbuf);
	char buf[HOSTLEN];

	strncpy(buf, inbuf, HOSTLEN);
	tptr = strrchr(buf, '.');

	if (tptr == NULL)
	{
		strncpy(outbuf, inbuf, HOSTLEN);
		return;
	}

	*tptr++ = '\0';

	snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum);
}

static void
do_host_cloak_host(const char *inbuf, char *outbuf)
{
	char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
	char *tptr;
	unsigned int accum = get_string_weighted_entropy(inbuf);

	strncpy(outbuf, inbuf, HOSTLEN);

	/* pass 1: scramble first section of hostname using base26 
	 * alphabet toasted against the weighted entropy of the string.
	 *
	 * numbers are not changed at this time, only letters.
	 */
	for (tptr = outbuf; *tptr != '\0'; tptr++)
	{
		if (*tptr == '.')
			break;

		if (isdigit(*tptr) || *tptr == '-')
			continue;

		*tptr = b26_alphabet[(*tptr * accum) % 26];
	}

	/* pass 2: scramble each number in the address */
	for (tptr = outbuf; *tptr != '\0'; tptr++)
	{
		if (isdigit(*tptr))
		{
			*tptr = 48 + ((*tptr * accum) % 10);
		}
	}	
}

static void
check_umode_change(void *vdata)
{
	hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
	struct Client *source_p = data->client;

	if (!MyClient(source_p))
		return;

	/* didn't change +h umode, we don't need to do anything */
	if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
		return;

	if (source_p->umodes & user_modes['h'])
	{
		if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
		{
			source_p->umodes &= ~user_modes['h'];
			return;
		}
		if (strcmp(source_p->host, source_p->localClient->mangledhost))
		{
			strlcpy(source_p->host, source_p->localClient->mangledhost, HOSTLEN);
			distribute_hostchange(source_p);
		}
		else /* not really nice, but we need to send this numeric here */
			sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
				source_p->host);
	}
	else if (!(source_p->umodes & user_modes['h']))
	{
		if (source_p->localClient->mangledhost != NULL &&
				!strcmp(source_p->host, source_p->localClient->mangledhost))
		{
			strlcpy(source_p->host, source_p->orighost, HOSTLEN);
			distribute_hostchange(source_p);
		}
	}
}

static void
check_new_user(void *vdata)
{
	struct Client *source_p = (void *)vdata;

	if (IsIPSpoof(source_p))
	{
		source_p->umodes &= ~user_modes['h'];
		return;
	}
	source_p->localClient->mangledhost = MyMalloc(HOSTLEN);
	if (!irccmp(source_p->orighost, source_p->sockhost))
		do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
	else
		do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
	if (IsDynSpoof(source_p))
		source_p->umodes &= ~user_modes['h'];
	if (source_p->umodes & user_modes['h'])
	{
		strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
		if (irccmp(source_p->host, source_p->orighost))
			SetDynSpoof(source_p);
	}
}
Commit	Line	Data
b076458c	1	/* $Id: ip_cloaking.c 3526 2007-07-06 07:56:14Z nenolod $ */
212380e3	2
	3	#include "stdinc.h"
	4	#include "modules.h"
	5	#include "hook.h"
	6	#include "client.h"
	7	#include "ircd.h"
	8	#include "send.h"
	9	#include "s_conf.h"
	10	#include "s_user.h"
	11	#include "s_serv.h"
	12	#include "tools.h"
	13	#include "numeric.h"
	14
	15	/* if you're modifying this module, you'll probably to change this */
	16	#define KEY 0x13748cfa
	17
	18	static int
	19	_modinit(void)
	20	{
	21	/* add the usermode to the available slot */
	22	user_modes['h'] = find_umode_slot();
	23	construct_umodebuf();
	24
	25	return 0;
	26	}
	27
	28	static void
	29	_moddeinit(void)
	30	{
	31	/* disable the umode and remove it from the available list */
	32	user_modes['h'] = 0;
	33	construct_umodebuf();
	34	}
	35
	36	static void check_umode_change(void *data);
	37	static void check_new_user(void *data);
	38	mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
	39	{ "umode_changed", (hookfn) check_umode_change },
	40	{ "new_local_user", (hookfn) check_new_user },
	41	{ NULL, NULL }
	42	};
	43
	44	DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
b076458c	45	ip_cloaking_hfnlist, "$Revision: 3526 $");
212380e3	46
	47	static void
	48	distribute_hostchange(struct Client *client)
	49	{
	50	if (irccmp(client->host, client->orighost))
	51	sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :is now your hidden host",
	52	client->host);
	53	else
	54	sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :hostname reset",
	55	client->host);
	56
	57	sendto_server(NULL, NULL,
	58	CAP_EUID \| CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
	59	use_id(&me), use_id(client), client->host);
	60	sendto_server(NULL, NULL,
	61	CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
	62	use_id(&me), use_id(client), client->host);
	63	sendto_server(NULL, NULL,
	64	NOCAPS, CAP_TS6, ":%s ENCAP * CHGHOST %s :%s",
	65	me.name, client->name, client->host);
	66	if (irccmp(client->host, client->orighost))
	67	SetDynSpoof(client);
	68	else
	69	ClearDynSpoof(client);
	70	}
	71
762cc38c	72	#define Nval 0x8c3a48ac
	73	#define HOSTLEN 63
	74	#define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */
	75
	76	static inline unsigned int
	77	get_string_entropy(const char *inbuf)
	78	{
	79	unsigned int accum = 1;
	80
	81	while(*inbuf != '\0')
	82	accum += *inbuf++;
	83
	84	return accum;
	85	}
	86
	87	/* calls get_string_entropy() and toasts it against INITDATA */
	88	static inline unsigned int
	89	get_string_weighted_entropy(const char *inbuf)
	90	{
	91	static int base_entropy = 0;
	92	unsigned int accum = get_string_entropy(inbuf);
	93
	94	/* initialize the algorithm if it is not yet ready */
	95	if (base_entropy == 0)
	96	base_entropy = get_string_entropy(INITDATA);
	97
	98	return (Nval * accum) ^ base_entropy;
	99	}
	100
212380e3	101	static void
762cc38c	102	do_host_cloak_ip(const char inbuf, char outbuf)
212380e3	103	{
762cc38c	104	char *tptr;
	105	unsigned int accum = get_string_weighted_entropy(inbuf);
	106	char buf[HOSTLEN];
	107
	108	strncpy(buf, inbuf, HOSTLEN);
	109	tptr = strrchr(buf, '.');
514235a7	110
514235a7	111	if (tptr == NULL)
b076458c	112	{
b076458c	113	strncpy(outbuf, inbuf, HOSTLEN);
514235a7	114	return;
b076458c	115	}
514235a7	116
762cc38c	117	*tptr++ = '\0';
212380e3	118
762cc38c	119	snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum);
	120	}
	121
	122	static void
	123	do_host_cloak_host(const char inbuf, char outbuf)
	124	{
	125	char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
	126	char *tptr;
	127	unsigned int accum = get_string_weighted_entropy(inbuf);
	128
	129	strncpy(outbuf, inbuf, HOSTLEN);
	130
	131	/* pass 1: scramble first section of hostname using base26
	132	* alphabet toasted against the weighted entropy of the string.
	133	*
	134	* numbers are not changed at this time, only letters.
	135	*/
	136	for (tptr = outbuf; *tptr != '\0'; tptr++)
212380e3	137	{
762cc38c	138	if (*tptr == '.')
	139	break;
	140
	141	if (isdigit(tptr) \|\| tptr == '-')
	142	continue;
	143
	144	tptr = b26_alphabet[(tptr * accum) % 26];
212380e3	145	}
762cc38c	146
	147	/* pass 2: scramble each number in the address */
	148	for (tptr = outbuf; *tptr != '\0'; tptr++)
	149	{
	150	if (isdigit(*tptr))
	151	{
	152	tptr = 48 + ((tptr * accum) % 10);
	153	}
	154	}
212380e3	155	}
	156
	157	static void
	158	check_umode_change(void *vdata)
	159	{
	160	hook_data_umode_changed data = (hook_data_umode_changed )vdata;
	161	struct Client *source_p = data->client;
	162
	163	if (!MyClient(source_p))
	164	return;
	165
	166	/* didn't change +h umode, we don't need to do anything */
	167	if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
	168	return;
	169
	170	if (source_p->umodes & user_modes['h'])
	171	{
	172	if (IsIPSpoof(source_p) \|\| source_p->localClient->mangledhost == NULL \|\| (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
	173	{
	174	source_p->umodes &= ~user_modes['h'];
	175	return;
	176	}
	177	if (strcmp(source_p->host, source_p->localClient->mangledhost))
	178	{
	179	strlcpy(source_p->host, source_p->localClient->mangledhost, HOSTLEN);
	180	distribute_hostchange(source_p);
	181	}
	182	else /* not really nice, but we need to send this numeric here */
	183	sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
	184	source_p->host);
	185	}
	186	else if (!(source_p->umodes & user_modes['h']))
	187	{
	188	if (source_p->localClient->mangledhost != NULL &&
	189	!strcmp(source_p->host, source_p->localClient->mangledhost))
	190	{
	191	strlcpy(source_p->host, source_p->orighost, HOSTLEN);
	192	distribute_hostchange(source_p);
	193	}
	194	}
	195	}
	196
	197	static void
	198	check_new_user(void *vdata)
	199	{
	200	struct Client source_p = (void )vdata;
	201
	202	if (IsIPSpoof(source_p))
	203	{
	204	source_p->umodes &= ~user_modes['h'];
	205	return;
	206	}
	207	source_p->localClient->mangledhost = MyMalloc(HOSTLEN);
	208	if (!irccmp(source_p->orighost, source_p->sockhost))
762cc38c	209	do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
212380e3	210	else
762cc38c	211	do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
212380e3	212	if (IsDynSpoof(source_p))
	213	source_p->umodes &= ~user_modes['h'];
	214	if (source_p->umodes & user_modes['h'])
	215	{
	216	strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
	217	if (irccmp(source_p->host, source_p->orighost))
	218	SetDynSpoof(source_p);
	219	}
	220	}