im.c

oscar message protocol stack

	int i;
	fu8_t ck[8];

	if (!sess || !(conn = aim_conn_findbygroup(sess, 0x0004)) || !sn)
		return -EINVAL;

	for (i = 0; i < 8; i++)
		ck[i] = (fu8_t)rand();

	if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x02, 10+8+2+1+strlen(sn) + 4+0x5e + 4)))
		return -ENOMEM;

	snacid = aim_cachesnac(sess, 0x0004, 0x0006, 0x0000, NULL, 0);
	aim_putsnac(&fr->data, 0x0004, 0x0006, 0x0000, snacid);

	/* ICBM header */
	aim_im_puticbm(&fr->data, ck, 0x0002, sn);

	/* TLV t(0005) - Encompasses almost everything below. */
	aimbs_put16(&fr->data, 0x0005); /* T */
	aimbs_put16(&fr->data, 0x005e); /* L */
	{ /* V */
		aimbs_put16(&fr->data, 0x0000);

		/* Cookie */
		aimbs_putraw(&fr->data, ck, 8);

		/* Put the 16 byte server relay capability */
		aim_putcap(&fr->data, AIM_CAPS_ICQSERVERRELAY);

		/* TLV t(000a) */
		aimbs_put16(&fr->data, 0x000a);
		aimbs_put16(&fr->data, 0x0002);
		aimbs_put16(&fr->data, 0x0001);

		/* TLV t(000f) */
		aimbs_put16(&fr->data, 0x000f);
		aimbs_put16(&fr->data, 0x0000);

		/* TLV t(2711) */
		aimbs_put16(&fr->data, 0x2711);
		aimbs_put16(&fr->data, 0x0036);
		{ /* V */
			aimbs_putle16(&fr->data, 0x001b); /* L */
			aimbs_putle16(&fr->data, 0x0008); /* XXX - Protocol version */
			aim_putcap(&fr->data, AIM_CAPS_EMPTY);
			aimbs_putle16(&fr->data, 0x0000); /* Unknown */
			aimbs_putle16(&fr->data, 0x0003); /* Client features? */
			aimbs_putle16(&fr->data, 0x0000); /* Unknown */
			aimbs_putle8(&fr->data, 0x00); /* Unkizown */
			aimbs_putle16(&fr->data, 0xffff); /* Sequence number?  XXX - This should decrement by 1 with each request */

			aimbs_putle16(&fr->data, 0x000e); /* L */
			aimbs_putle16(&fr->data, 0xffff); /* Sequence number?  XXX - This should decrement by 1 with each request */
			aimbs_putle32(&fr->data, 0x00000000); /* Unknown */
			aimbs_putle32(&fr->data, 0x00000000); /* Unknown */
			aimbs_putle32(&fr->data, 0x00000000); /* Unknown */

			/* The type of status message being requested */
			if (type & AIM_ICQ_STATE_CHAT)
				aimbs_putle16(&fr->data, 0x03ec);
			else if(type & AIM_ICQ_STATE_DND)
				aimbs_putle16(&fr->data, 0x03eb);
			else if(type & AIM_ICQ_STATE_OUT)
				aimbs_putle16(&fr->data, 0x03ea);
			else if(type & AIM_ICQ_STATE_BUSY)
				aimbs_putle16(&fr->data, 0x03e9);
			else if(type & AIM_ICQ_STATE_AWAY)
				aimbs_putle16(&fr->data, 0x03e8);

			aimbs_putle16(&fr->data, 0x0000); /* Status? */
			aimbs_putle16(&fr->data, 0x0001); /* Priority of this message? */
			aimbs_putle16(&fr->data, 0x0001); /* L */
			aimbs_putle8(&fr->data, 0x00); /* String of length L */
		} /* End TLV t(2711) */
	} /* End TLV t(0005) */

	/* TLV t(0003) */
	aimbs_put16(&fr->data, 0x0003);
	aimbs_put16(&fr->data, 0x0000);

	aim_tx_enqueue(sess, fr);

	return 0;
}

/**
 * Subtype 0x0006 - Send an ICQ-esque ICBM.
 *
 * This can be used to send an ICQ authorization reply (deny or grant).  It is the "old way."  
 * The new way is to use SSI.  I like the new way a lot better.  This seems like such a hack, 
 * mostly because it's in network byte order.  Figuring this stuff out sometimes takes a while, 
 * but thats ok, because it gives me time to try to figure out what kind of drugs the AOL people 
 * were taking when they merged the two protocols.
 *
 * @param sn The destination screen name.
 * @param type The type of message.  0x0007 for authorization denied.  0x0008 for authorization granted.
 * @param message The message you want to send, it should be null terminated.
 * @return Return 0 if no errors, otherwise return the error number.
 */
faim_export int aim_im_sendch4(aim_session_t *sess, char *sn, fu16_t type, fu8_t *message)
{
	aim_conn_t *conn;
	aim_frame_t *fr;
	aim_snacid_t snacid;
	int i;
	char ck[8];

	if (!sess || !(conn = aim_conn_findbygroup(sess, 0x0002)))
		return -EINVAL;

	if (!sn || !type || !message)
		return -EINVAL;

	if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x02, 10+8+3+strlen(sn)+12+strlen(message)+1+4)))
		return -ENOMEM;

	snacid = aim_cachesnac(sess, 0x0004, 0x0006, 0x0000, NULL, 0);
	aim_putsnac(&fr->data, 0x0004, 0x0006, 0x0000, snacid);

	/* Cookie */
	for (i=0; i<8; i++)
		ck[i] = (fu8_t)rand();

	/* ICBM header */
	aim_im_puticbm(&fr->data, ck, 0x0004, sn);

	/*
	 * TLV t(0005)
	 *
	 * ICQ data (the UIN and the message).
	 */
	aimbs_put16(&fr->data, 0x0005);
	aimbs_put16(&fr->data, 4 + 2+2+strlen(message)+1);

	/*
	 * Your UIN
	 */
	aimbs_putle32(&fr->data, atoi(sess->sn));

	/*
	 * TLV t(type) l(strlen(message)+1) v(message+NULL)
	 */
	aimbs_putle16(&fr->data, type);
	aimbs_putle16(&fr->data, strlen(message)+1);
	aimbs_putraw(&fr->data, message, strlen(message)+1);

	/*
	 * TLV t(0006) l(0000) v()
	 */
	aimbs_put16(&fr->data, 0x0006);
	aimbs_put16(&fr->data, 0x0000);

	aim_tx_enqueue(sess, fr);

	return 0;
}

/*
 * XXX - I don't see when this would ever get called...
 */
static int outgoingim(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
	int i, ret = 0;
	aim_rxcallback_t userfunc;
	fu8_t cookie[8];
	fu16_t channel;
	aim_tlvlist_t *tlvlist;
	char *sn;
	int snlen;
	fu16_t icbmflags = 0;
	fu8_t flag1 = 0, flag2 = 0;
	fu8_t *msg = NULL;
	aim_tlv_t *msgblock;

	/* ICBM Cookie. */
	for (i = 0; i < 8; i++)
		cookie[i] = aimbs_get8(bs);

	/* Channel ID */
	channel = aimbs_get16(bs);

	if (channel != 0x01) {
		faimdprintf(sess, 0, "icbm: ICBM recieved on unsupported channel.  Ignoring. (chan = %04x)\n", channel);
		return 0;
	}

	snlen = aimbs_get8(bs);
	sn = aimbs_getstr(bs, snlen);

	tlvlist = aim_tlvlist_read(bs);

	if (aim_tlv_gettlv(tlvlist, 0x0003, 1))
		icbmflags |= AIM_IMFLAGS_ACK;
	if (aim_tlv_gettlv(tlvlist, 0x0004, 1))
		icbmflags |= AIM_IMFLAGS_AWAY;

	if ((msgblock = aim_tlv_gettlv(tlvlist, 0x0002, 1))) {
		aim_bstream_t mbs;
		int featurelen, msglen;

		aim_bstream_init(&mbs, msgblock->value, msgblock->length);

		aimbs_get8(&mbs);
		aimbs_get8(&mbs);
		for (featurelen = aimbs_get16(&mbs); featurelen; featurelen--)
			aimbs_get8(&mbs);
		aimbs_get8(&mbs);
		aimbs_get8(&mbs);

		msglen = aimbs_get16(&mbs) - 4; /* final block length */

		flag1 = aimbs_get16(&mbs);
		flag2 = aimbs_get16(&mbs);

		msg = aimbs_getstr(&mbs, msglen);
	}

	if ((userfunc = aim_callhandler(sess, rx->conn, snac->family, snac->subtype)))
		ret = userfunc(sess, rx, channel, sn, msg, icbmflags, flag1, flag2);

	free(sn);
	aim_tlvlist_free(&tlvlist);

	return ret;
}

/*
 * Ahh, the joys of nearly ridiculous over-engineering.
 *
 * Not only do AIM ICBM's support multiple channels.  Not only do they
 * support multiple character sets.  But they support multiple character 
 * sets / encodings within the same ICBM.
 *
 * These multipart messages allow for complex space savings techniques, which
 * seem utterly unnecessary by today's standards.  In fact, there is only
 * one client still in popular use that still uses this method: AOL for the
 * Macintosh, Version 5.0.  Obscure, yes, I know.  
 *
 * In modern (non-"legacy") clients, if the user tries to send a character
 * that is not ISO-8859-1 or ASCII, the client will send the entire message
 * as UNICODE, meaning that every character in the message will occupy the
 * full 16 bit UNICODE field, even if the high order byte would be zero.
 * Multipart messages prevent this wasted space by allowing the client to
 * only send the characters in UNICODE that need to be sent that way, and
 * the rest of the message can be sent in whatever the native character 
 * set is (probably ASCII).
 *
 * An important note is that sections will be displayed in the order that
 * they appear in the ICBM.  There is no facility for merging or rearranging
 * sections at run time.  So if you have, say, ASCII then UNICODE then ASCII,
 * you must supply two ASCII sections with a UNICODE in the middle, and incur
 * the associated overhead.
 *
 * Normally I would have laughed and given a firm 'no' to supporting this
 * seldom-used feature, but something is attracting me to it.  In the future,
 * it may be possible to abuse this to send mixed-media messages to other
 * open source clients (like encryption or something) -- see faimtest for
 * examples of how to do this.
 *
 * I would definitely recommend avoiding this feature unless you really
 * know what you are doing, and/or you have something neat to do with it.
 *
 */
faim_export int aim_mpmsg_init(aim_session_t *sess, aim_mpmsg_t *mpm)
{

	memset(mpm, 0, sizeof(aim_mpmsg_t));

	return 0;
}

static int mpmsg_addsection(aim_session_t *sess, aim_mpmsg_t *mpm, fu16_t charset, fu16_t charsubset, fu8_t *data, fu16_t datalen)
{
	aim_mpmsg_section_t *sec; 
	
	if (!(sec = malloc(sizeof(aim_mpmsg_section_t))))
		return -1;

	sec->charset = charset;
	sec->charsubset = charsubset;
	sec->data = data;
	sec->datalen = datalen;
	sec->next = NULL;

	if (!mpm->parts)
		mpm->parts = sec;
	else {
		aim_mpmsg_section_t *cur;

		for (cur = mpm->parts; cur->next; cur = cur->next)
			;
		cur->next = sec;
	}

	mpm->numparts++;

	return 0;
}

faim_export int aim_mpmsg_addraw(aim_session_t *sess, aim_mpmsg_t *mpm, fu16_t charset, fu16_t charsubset, const fu8_t *data, fu16_t datalen)
{
	fu8_t *dup;

	if (!(dup = malloc(datalen)))
		return -1;
	memcpy(dup, data, datalen);

	if (mpmsg_addsection(sess, mpm, charset, charsubset, dup, datalen) == -1) {
		free(dup);
		return -1;
	}

	return 0;
}

/* XXX - should provide a way of saying ISO-8859-1 specifically */
faim_export int aim_mpmsg_addascii(aim_session_t *sess, aim_mpmsg_t *mpm, const char *ascii)
{
	fu8_t *dup;

	if (!(dup = strdup(ascii))) 
		return -1;

	if (mpmsg_addsection(sess, mpm, 0x0000, 0x0000, dup, strlen(ascii)) == -1) {
		free(dup);
		return -1;
	}

	return 0;
}

faim_export int aim_mpmsg_addunicode(aim_session_t *sess, aim_mpmsg_t *mpm, const fu16_t *unicode, fu16_t unicodelen)
{
	fu8_t *buf;
	aim_bstream_t bs;
	int i;

	if (!(buf = malloc(unicodelen * 2)))
		return -1;

	aim_bstream_init(&bs, buf, unicodelen * 2);

	/* We assume unicode is in /host/ byte order -- convert to network */
	for (i = 0; i < unicodelen; i++)
		aimbs_put16(&bs, unicode[i]);

	if (mpmsg_addsection(sess, mpm, 0x0002, 0x0000, buf, aim_bstream_curpos(&bs)) == -1) {
		free(buf);
		return -1;
	}
	
	return 0;
}

faim_export void aim_mpmsg_free(aim_session_t *sess, aim_mpmsg_t *mpm)
{
	aim_mpmsg_section_t *cur;

	for (cur = mpm->parts; cur; ) {
		aim_mpmsg_section_t *tmp;
		
		tmp = cur->next;
		free(cur->data);
		free(cur);
		cur = tmp;
	}
	
	mpm->numparts = 0;
	mpm->parts = NULL;

	return;
}

/*
 * Start by building the multipart structures, then pick the first 
 * human-readable section and stuff it into args->msg so no one gets
 * suspicious.
 *
 */
static int incomingim_ch1_parsemsgs(aim_session_t *sess, fu8_t *data, int len, struct aim_incomingim_ch1_args *args)
{
	/* Should this be ASCII -> UNICODE -> Custom */
	static const fu16_t charsetpri[] = {
		AIM_CHARSET_ASCII, /* ASCII first */
		AIM_CHARSET_CUSTOM, /* then ISO-8859-1 */
		AIM_CHARSET_UNICODE, /* UNICODE as last resort */
	};
	static const int charsetpricount = 3;
	int i;
	aim_bstream_t mbs;
	aim_mpmsg_section_t *sec;

	aim_bstream_init(&mbs, data, len);

	while (aim_bstream_empty(&mbs)) {
		fu16_t msglen, flag1, flag2;
		fu8_t *msgbuf;

		aimbs_get8(&mbs); /* 01 */
		aimbs_get8(&mbs); /* 01 */

		/* Message string length, including character set info. */
		msglen = aimbs_get16(&mbs);

		/* Character set info */
		flag1 = aimbs_get16(&mbs);
		flag2 = aimbs_get16(&mbs);

		/* Message. */
		msglen -= 4;

		/*
		 * For now, we don't care what the encoding is.  Just copy
		 * it into a multipart struct and deal with it later. However,
		 * always pad the ending with a NULL.  This makes it easier
		 * to treat ASCII sections as strings.  It won't matter for
		 * UNICODE or binary data, as you should never read past
		 * the specified data length, which will not include the pad.
		 *
		 * XXX - There's an API bug here.  For sending, the UNICODE is
		 * given in host byte order (aim_mpmsg_addunicode), but here
		 * the received messages are given in network byte order.
		 *
		 */
		msgbuf = aimbs_getstr(&mbs, msglen);
		mpmsg_addsection(sess, &args->mpmsg, flag1, flag2, msgbuf, msglen);

	} /* while */

	args->icbmflags |= AIM_IMFLAGS_MULTIPART; /* always set */

	/*
	 * Clients that support multiparts should never use args->msg, as it
	 * will point to an arbitrary section.
	 *
	 * Here, we attempt to provide clients that do not support multipart
	 * messages with something to look at -- hopefully a human-readable
	 * string.  But, failing that, a UNICODE message, or nothing at all.
	 *
	 * Which means that even if args->msg is NULL, it does not mean the
	 * message was blank.
	 *
	 */
	for (i = 0; i < charsetpricount; i++) {
		for (sec = args->mpmsg.parts; sec; sec = sec->next) {

			if (sec->charset != charsetpri[i])
				continue;

			/* Great. We found one.  Fill it in. */
			args->charset = sec->charset;
			args->charsubset = sec->charsubset;

			/* Set up the simple flags */
			if (args->charsubset == 0x0000)
				; /* standard subencoding? */
			else if (args->charsubset == 0x000b)
				args->icbmflags |= AIM_IMFLAGS_SUBENC_MACINTOSH;
			else if (args->charsubset == 0xffff)
				; /* no subencoding */

			args->msg = sec->data;
			args->msglen = sec->datalen;