service.c

oscar message protocol stack

/*
 * Family 0x0001 - This is a very special group.  All connections support
 * this group, as it does some particularly good things (like rate limiting).
 */

#define FAIM_INTERNAL
#define FAIM_NEED_CONN_INTERNAL
#include <aim.h>

#include "md5.h"

/* Subtype 0x0002 - Client Online */
faim_export int aim_clientready(aim_session_t *sess, aim_conn_t *conn)
{
	aim_conn_inside_t *ins = (aim_conn_inside_t *)conn->inside;
	struct snacgroup *sg;
	aim_frame_t *fr;
	aim_snacid_t snacid;

	if (!ins)
		return -EINVAL;

	if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x02, 1152)))
		return -ENOMEM;

	snacid = aim_cachesnac(sess, 0x0001, 0x0002, 0x0000, NULL, 0);
	aim_putsnac(&fr->data, 0x0001, 0x0002, 0x0000, snacid);

	/*
	 * Send only the tool versions that the server cares about (that it
	 * marked as supporting in the server ready SNAC).  
	 */
	for (sg = ins->groups; sg; sg = sg->next) {
		aim_module_t *mod;

		if ((mod = aim__findmodulebygroup(sess, sg->group))) {
			aimbs_put16(&fr->data, mod->family);
			aimbs_put16(&fr->data, mod->version);
			aimbs_put16(&fr->data, mod->toolid);
			aimbs_put16(&fr->data, mod->toolversion);
		} else
			faimdprintf(sess, 1, "aim_clientready: server supports group 0x%04x but we don't!\n", sg->group);
	}

	aim_tx_enqueue(sess, fr);

	return 0;
}

/*
 * Subtype 0x0003 - Host Online
 * 
 * See comments in conn.c about how the group associations are supposed
 * to work, and how they really work.
 *
 * This info probably doesn't even need to make it to the client.
 *
 * We don't actually call the client here.  This starts off the connection
 * initialization routine required by all AIM connections.  The next time
 * the client is called is the CONNINITDONE callback, which should be 
 * shortly after the rate information is acknowledged.
 * 
 */
static int hostonline(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
	fu16_t *families;
	int famcount;


	if (!(families = malloc(aim_bstream_empty(bs))))
		return 0;

	for (famcount = 0; aim_bstream_empty(bs); famcount++) {
		families[famcount] = aimbs_get16(bs);
		aim_conn_addgroup(rx->conn, families[famcount]);
	}

	free(families);


	/*
	 * Next step is in the Host Versions handler.
	 *
	 * Note that we must send this before we request rates, since
	 * the format of the rate information depends on the versions we
	 * give it.
	 *
	 */
	aim_setversions(sess, rx->conn);

	return 1; 
}

/* Subtype 0x0004 - Service request */
faim_export int aim_reqservice(aim_session_t *sess, aim_conn_t *conn, fu16_t serviceid)
{
	return aim_genericreq_s(sess, conn, 0x0001, 0x0004, &serviceid);
}

/*
 * Join a room of name roomname.  This is the first step to joining an 
 * already created room.  It's basically a Service Request for 
 * family 0x000e, with a little added on to specify the exchange and room 
 * name.
 */
faim_export int aim_chat_join(aim_session_t *sess, aim_conn_t *conn, fu16_t exchange, const char *roomname, fu16_t instance)
{
	aim_frame_t *fr;
	aim_snacid_t snacid;
	aim_tlvlist_t *tl = NULL;
	struct chatsnacinfo csi;
	
	if (!sess || !conn || !roomname || !strlen(roomname))
		return -EINVAL;

	if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x02, 512)))
		return -ENOMEM;

	memset(&csi, 0, sizeof(csi));
	csi.exchange = exchange;
	strncpy(csi.name, roomname, sizeof(csi.name));
	csi.instance = instance;

	snacid = aim_cachesnac(sess, 0x0001, 0x0004, 0x0000, &csi, sizeof(csi));
	aim_putsnac(&fr->data, 0x0001, 0x0004, 0x0000, snacid);

	/*
	 * Requesting service chat (0x000e)
	 */
	aimbs_put16(&fr->data, 0x000e);

	aim_tlvlist_add_chatroom(&tl, 0x0001, exchange, roomname, instance);
	aim_tlvlist_write(&fr->data, &tl);
	aim_tlvlist_free(&tl);

	aim_tx_enqueue(sess, fr);

	return 0; 
}

/* Subtype 0x0005 - Redirect */
static int redirect(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
	struct aim_redirect_data redir;
	aim_rxcallback_t userfunc;
	aim_tlvlist_t *tlvlist;
	aim_snac_t *origsnac = NULL;
	int ret = 0;

	memset(&redir, 0, sizeof(redir));

	tlvlist = aim_tlvlist_read(bs);

	if (!aim_tlv_gettlv(tlvlist, 0x000d, 1) ||
			!aim_tlv_gettlv(tlvlist, 0x0005, 1) ||
			!aim_tlv_gettlv(tlvlist, 0x0006, 1)) {
		aim_tlvlist_free(&tlvlist);
		return 0;
	}

	redir.group = aim_tlv_get16(tlvlist, 0x000d, 1);
	redir.ip = aim_tlv_getstr(tlvlist, 0x0005, 1);
	redir.cookielen = aim_tlv_gettlv(tlvlist, 0x0006, 1)->length;
	redir.cookie = aim_tlv_getstr(tlvlist, 0x0006, 1);

	/* Fetch original SNAC so we can get csi if needed */
	origsnac = aim_remsnac(sess, snac->id);

	if ((redir.group == AIM_CONN_TYPE_CHAT) && origsnac) {
		struct chatsnacinfo *csi = (struct chatsnacinfo *)origsnac->data;

		redir.chat.exchange = csi->exchange;
		redir.chat.room = csi->name;
		redir.chat.instance = csi->instance;
	}

	if ((userfunc = aim_callhandler(sess, rx->conn, snac->family, snac->subtype)))
		ret = userfunc(sess, rx, &redir);

	free((void *)redir.ip);
	free((void *)redir.cookie);

	if (origsnac)
		free(origsnac->data);
	free(origsnac);

	aim_tlvlist_free(&tlvlist);

	return ret;
}

/* Subtype 0x0006 - Request Rate Information. */
faim_internal int aim_reqrates(aim_session_t *sess, aim_conn_t *conn)
{
	return aim_genericreq_n_snacid(sess, conn, 0x0001, 0x0006);
}

/*
 * OSCAR defines several 'rate classes'.  Each class has separate
 * rate limiting properties (limit level, alert level, disconnect
 * level, etc), and a set of SNAC family/type pairs associated with
 * it.  The rate classes, their limiting properties, and the definitions
 * of which SNACs are belong to which class, are defined in the
 * Rate Response packet at login to each host.  
 *
 * Logically, all rate offenses within one class count against further
 * offenses for other SNACs in the same class (ie, sending messages
 * too fast will limit the number of user info requests you can send,
 * since those two SNACs are in the same rate class).
 *
 * Since the rate classes are defined dynamically at login, the values
 * below may change. But they seem to be fairly constant.
 *
 * Currently, BOS defines five rate classes, with the commonly used
 * members as follows...
 *
 *  Rate class 0x0001:
 *  	- Everything thats not in any of the other classes
 *
 *  Rate class 0x0002:
 * 	- Buddy list add/remove
 *	- Permit list add/remove
 *	- Deny list add/remove
 *
 *  Rate class 0x0003:
 *	- User information requests
 *	- Outgoing ICBMs
 *
 *  Rate class 0x0004:
 *	- A few unknowns: 2/9, 2/b, and f/2
 *
 *  Rate class 0x0005:
 *	- Chat room create
 *	- Outgoing chat ICBMs
 *
 * The only other thing of note is that class 5 (chat) has slightly looser
 * limiting properties than class 3 (normal messages).  But thats just a 
 * small bit of trivia for you.
 *
 * The last thing that needs to be learned about the rate limiting
 * system is how the actual numbers relate to the passing of time.  This
 * seems to be a big mystery.
 * 
 */

static void rc_addclass(struct rateclass **head, struct rateclass *inrc)
{
	struct rateclass *rc, *rc2;

	if (!(rc = malloc(sizeof(struct rateclass))))
		return;

	memcpy(rc, inrc, sizeof(struct rateclass));
	rc->next = NULL;

	for (rc2 = *head; rc2 && rc2->next; rc2 = rc2->next)
		;

	if (!rc2)
		*head = rc;
	else
		rc2->next = rc;

	return;
}

static struct rateclass *rc_findclass(struct rateclass **head, fu16_t id)
{
	struct rateclass *rc;

	for (rc = *head; rc; rc = rc->next) {
		if (rc->classid == id)
			return rc;
	}

	return NULL;
}

static void rc_addpair(struct rateclass *rc, fu16_t group, fu16_t type)
{
	struct snacpair *sp, *sp2;

	if (!(sp = malloc(sizeof(struct snacpair))))
		return;
	memset(sp, 0, sizeof(struct snacpair));

	sp->group = group;
	sp->subtype = type;
	sp->next = NULL;

	for (sp2 = rc->members; sp2 && sp2->next; sp2 = sp2->next)
		;

	if (!sp2)
		rc->members = sp;
	else
		sp2->next = sp;

	return;
}

/* Subtype 0x0007 - Rate Parameters */
static int rateresp(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
	aim_conn_inside_t *ins = (aim_conn_inside_t *)rx->conn->inside;
	fu16_t numclasses, i;
	aim_rxcallback_t userfunc;


	/*
	 * First are the parameters for each rate class.
	 */
	numclasses = aimbs_get16(bs);
	for (i = 0; i < numclasses; i++) {
		struct rateclass rc;

		memset(&rc, 0, sizeof(struct rateclass));

		rc.classid = aimbs_get16(bs);
		rc.windowsize = aimbs_get32(bs);
		rc.clear = aimbs_get32(bs);
		rc.alert = aimbs_get32(bs);
		rc.limit = aimbs_get32(bs);
		rc.disconnect = aimbs_get32(bs);
		rc.current = aimbs_get32(bs);
		rc.max = aimbs_get32(bs);

		/*
		 * The server will send an extra five bytes of parameters
		 * depending on the version we advertised in 1/17.  If we
		 * didn't send 1/17 (evil!), then this will crash and you
		 * die, as it will default to the old version but we have 
		 * the new version hardcoded here. 
		 */
		if (mod->version >= 3)
			aimbs_getrawbuf(bs, rc.unknown, sizeof(rc.unknown));

		faimdprintf(sess, 1, "--- Adding rate class %d to connection type %d: window size = %ld, clear = %ld, alert = %ld, limit = %ld, disconnect = %ld, current = %ld, max = %ld\n", rx->conn->type, rc.classid, rc.windowsize, rc.clear, rc.alert, rc.limit, rc.disconnect, rc.current, rc.max);

		rc_addclass(&ins->rates, &rc);
	}

	/*
	 * Then the members of each class.
	 */
	for (i = 0; i < numclasses; i++) {
		fu16_t classid, count;
		struct rateclass *rc;
		int j;

		classid = aimbs_get16(bs);
		count = aimbs_get16(bs);

		rc = rc_findclass(&ins->rates, classid);

		for (j = 0; j < count; j++) {
			fu16_t group, subtype;

			group = aimbs_get16(bs);
			subtype = aimbs_get16(bs);

			if (rc)
				rc_addpair(rc, group, subtype);
		}
	}

	/*
	 * We don't pass the rate information up to the client, as it really
	 * doesn't care.  The information is stored in the connection, however
	 * so that we can do more fun stuff later (not really).
	 */

	/*
	 * Last step in the conn init procedure is to acknowledge that we
	 * agree to these draconian limitations.
	 */
	aim_rates_addparam(sess, rx->conn);