source: protocols/oscar/service.c @ 5ffa4f7

/*
 * Group 1.  This is a very special group.  All connections support
 * this group, as it does some particularly good things (like rate limiting).
 */

#include <aim.h>

#include "md5.h"

/* Client Online (group 1, subtype 2) */
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);
                } 
        }

        aim_tx_enqueue(sess, fr);

        return 0;
}

/*
 * Host Online (group 1, type 3)
 * 
 * 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)
{
        guint16 *families;
        int famcount;


        if (!(families = g_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]);
        }

        g_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; 
}

/* Service request (group 1, type 4) */
int aim_reqservice(aim_session_t *sess, aim_conn_t *conn, guint16 serviceid)
{
        return aim_genericreq_s(sess, conn, 0x0001, 0x0004, &serviceid);
}

/* Redirect (group 1, type 5) */
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_readtlvchain(bs);

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

        redir.group = aim_gettlv16(tlvlist, 0x000d, 1);
        redir.ip = aim_gettlv_str(tlvlist, 0x0005, 1);
        redir.cookie = (guint8 *)aim_gettlv_str(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);

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

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

        aim_freetlvchain(&tlvlist);

        return ret;
}

/* Request Rate Information. (group 1, type 6) */
int aim_reqrates(aim_session_t *sess, aim_conn_t *conn)
{
        return aim_genericreq_n(sess, conn, 0x0001, 0x0006);
}

/*
 * OSCAR defines several 'rate classes'.  Each class has seperate
 * 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 = g_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, guint16 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, guint16 group, guint16 type)
{
        struct snacpair *sp, *sp2;

        if (!(sp = g_new0(struct snacpair, 1)))
                return;

        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;
}

/* Rate Parameters (group 1, type 7) */
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;
        guint16 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));

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

        /*
         * Then the members of each class.
         */
        for (i = 0; i < numclasses; i++) {
                guint16 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++) {
                        guint16 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);

        /*
         * Finally, tell the client it's ready to go...
         */
        if ((userfunc = aim_callhandler(sess, rx->conn, AIM_CB_FAM_SPECIAL, AIM_CB_SPECIAL_CONNINITDONE)))
                userfunc(sess, rx);


        return 1;
}

/* Add Rate Parameter (group 1, type 8) */
int aim_rates_addparam(aim_session_t *sess, aim_conn_t *conn)
{
        aim_conn_inside_t *ins = (aim_conn_inside_t *)conn->inside;
        aim_frame_t *fr;        
        aim_snacid_t snacid;
        struct rateclass *rc;

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

        snacid = aim_cachesnac(sess, 0x0001, 0x0008, 0x0000, NULL, 0);
        aim_putsnac(&fr->data, 0x0001, 0x0008, 0x0000, snacid);

        for (rc = ins->rates; rc; rc = rc->next)
                aimbs_put16(&fr->data, rc->classid);

        aim_tx_enqueue(sess, fr);

        return 0;
}

/* Delete Rate Parameter (group 1, type 9) */
int aim_rates_delparam(aim_session_t *sess, aim_conn_t *conn)
{
        aim_conn_inside_t *ins = (aim_conn_inside_t *)conn->inside;
        aim_frame_t *fr;        
        aim_snacid_t snacid;
        struct rateclass *rc;

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

        snacid = aim_cachesnac(sess, 0x0001, 0x0009, 0x0000, NULL, 0);
        aim_putsnac(&fr->data, 0x0001, 0x0009, 0x0000, snacid);

        for (rc = ins->rates; rc; rc = rc->next)
                aimbs_put16(&fr->data, rc->classid);

        aim_tx_enqueue(sess, fr);

        return 0;
}

/* Rate Change (group 1, type 0x0a) */
static int ratechange(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;
        guint16 code, rateclass;
        guint32 currentavg, maxavg, windowsize, clear, alert, limit, disconnect;

        code = aimbs_get16(bs);
        rateclass = aimbs_get16(bs);
        
        windowsize = aimbs_get32(bs);
        clear = aimbs_get32(bs);
        alert = aimbs_get32(bs);
        limit = aimbs_get32(bs);
        disconnect = aimbs_get32(bs);
        currentavg = aimbs_get32(bs);
        maxavg = aimbs_get32(bs);

        if ((userfunc = aim_callhandler(sess, rx->conn, snac->family, snac->subtype)))
                return userfunc(sess, rx, code, rateclass, windowsize, clear, alert, limit, disconnect, currentavg, maxavg);

        return 0;
}

/*
 * How Migrations work.  
 *
 * The server sends a Server Pause message, which the client should respond to 
 * with a Server Pause Ack, which contains the families it needs on this 
 * connection. The server will send a Migration Notice with an IP address, and 
 * then disconnect. Next the client should open the connection and send the 
 * cookie.  Repeat the normal login process and pretend this never happened.
 *
 * The Server Pause contains no data.
 *
 */

/* Service Pause (group 1, type 0x0b) */
static int serverpause(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;

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

        return 0;
}

/*
 * Service Pause Acknowledgement (group 1, type 0x0c)
 *
 * It is rather important that aim_sendpauseack() gets called for the exact
 * same connection that the Server Pause callback was called for, since
 * libfaim extracts the data for the SNAC from the connection structure.
 *
 * Of course, if you don't do that, more bad things happen than just what
 * libfaim can cause.
 *
 */
int aim_sendpauseack(aim_session_t *sess, aim_conn_t *conn)
{
        aim_frame_t *fr;
        aim_snacid_t snacid;
        aim_conn_inside_t *ins = (aim_conn_inside_t *)conn->inside;
        struct snacgroup *sg;

        if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x02, 1024)))
                return -ENOMEM;

        snacid = aim_cachesnac(sess, 0x0001, 0x000c, 0x0000, NULL, 0);
        aim_putsnac(&fr->data, 0x0001, 0x000c, 0x0000, snacid);

        /*
         * This list should have all the groups that the original 
         * Host Online / Server Ready said this host supports.  And 
         * we want them all back after the migration.
         */
        for (sg = ins->groups; sg; sg = sg->next)
                aimbs_put16(&fr->data, sg->group);

        aim_tx_enqueue(sess, fr);

        return 0;
}

/* Service Resume (group 1, type 0x0d) */
static int serverresume(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;

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

        return 0;
}

/* Request self-info (group 1, type 0x0e) */
int aim_reqpersonalinfo(aim_session_t *sess, aim_conn_t *conn)
{
        return aim_genericreq_n(sess, conn, 0x0001, 0x000e);
}

/* Self User Info (group 1, type 0x0f) */
static int selfinfo(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;
        aim_userinfo_t userinfo;

        aim_extractuserinfo(sess, bs, &userinfo);

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

        return 0;
}

/* Evil Notification (group 1, type 0x10) */
static int evilnotify(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;
        guint16 newevil;
        aim_userinfo_t userinfo;

        memset(&userinfo, 0, sizeof(aim_userinfo_t));
        
        newevil = aimbs_get16(bs);

        if (aim_bstream_empty(bs))
                aim_extractuserinfo(sess, bs, &userinfo);

        if ((userfunc = aim_callhandler(sess, rx->conn, snac->family, snac->subtype)))
                return userfunc(sess, rx, newevil, &userinfo);

        return 0;
}

/*
 * Idle Notification (group 1, type 0x11)
 *
 * Should set your current idle time in seconds.  Note that this should
 * never be called consecutively with a non-zero idle time.  That makes
 * OSCAR do funny things.  Instead, just set it once you go idle, and then
 * call it again with zero when you're back.
 *
 */
int aim_bos_setidle(aim_session_t *sess, aim_conn_t *conn, guint32 idletime)
{
        return aim_genericreq_l(sess, conn, 0x0001, 0x0011, &idletime);
}

/*
 * Service Migrate (group 1, type 0x12)
 *
 * This is the final SNAC sent on the original connection during a migration.
 * It contains the IP and cookie used to connect to the new server, and 
 * optionally a list of the SNAC groups being migrated.
 *
 */
static int migrate(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;
        int ret = 0;
        guint16 groupcount, i;
        aim_tlvlist_t *tl;
        char *ip = NULL;
        aim_tlv_t *cktlv;

        /*
         * Apparently there's some fun stuff that can happen right here. The
         * migration can actually be quite selective about what groups it
         * moves to the new server.  When not all the groups for a connection
         * are migrated, or they are all migrated but some groups are moved
         * to a different server than others, it is called a bifurcated 
         * migration.
         *
         * Let's play dumb and not support that.
         *
         */
        groupcount = aimbs_get16(bs);
        for (i = 0; i < groupcount; i++) {
                aimbs_get16(bs);

                imcb_error(sess->aux_data, "bifurcated migration unsupported");
        }

        tl = aim_readtlvchain(bs);

        if (aim_gettlv(tl, 0x0005, 1))
                ip = aim_gettlv_str(tl, 0x0005, 1);

        cktlv = aim_gettlv(tl, 0x0006, 1);

        if ((userfunc = aim_callhandler(sess, rx->conn, snac->family, snac->subtype)))
                ret = userfunc(sess, rx, ip, cktlv ? cktlv->value : NULL);

        aim_freetlvchain(&tl);
        g_free(ip);

        return ret;
}

/* Message of the Day (group 1, type 0x13) */
static int motd(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;
        char *msg = NULL;
        int ret = 0;
        aim_tlvlist_t *tlvlist;
        guint16 id;

        /*
         * Code.
         *
         * Valid values:
         *   1 Mandatory upgrade
         *   2 Advisory upgrade
         *   3 System bulletin
         *   4 Nothing's wrong ("top o the world" -- normal)
         *   5 Lets-break-something. 
         *
         */
        id = aimbs_get16(bs);

        /* 
         * TLVs follow 
         */
        tlvlist = aim_readtlvchain(bs);

        msg = aim_gettlv_str(tlvlist, 0x000b, 1);

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

        g_free(msg);

        aim_freetlvchain(&tlvlist);

        return ret;
}

/* 
 * Set privacy flags (group 1, type 0x14)
 *
 * Normally 0x03.
 *
 *  Bit 1:  Allows other AIM users to see how long you've been idle.
 *  Bit 2:  Allows other AIM users to see how long you've been a member.
 *
 */
int aim_bos_setprivacyflags(aim_session_t *sess, aim_conn_t *conn, guint32 flags)
{
        return aim_genericreq_l(sess, conn, 0x0001, 0x0014, &flags);
}

/*
 * No-op (group 1, type 0x16)
 *
 * WinAIM sends these every 4min or so to keep the connection alive.  Its not 
 * real necessary.
 *
 */
int aim_nop(aim_session_t *sess, aim_conn_t *conn)
{
        return aim_genericreq_n(sess, conn, 0x0001, 0x0016);
}

/* 
 * Set client versions (group 1, subtype 0x17) 
 *
 * If you've seen the clientonline/clientready SNAC you're probably 
 * wondering what the point of this one is.  And that point seems to be
 * that the versions in the client online SNAC are sent too late for the
 * server to be able to use them to change the protocol for the earlier
 * login packets (client versions are sent right after Host Online is 
 * received, but client online versions aren't sent until quite a bit later).
 * We can see them already making use of this by changing the format of
 * the rate information based on what version of group 1 we advertise here.
 *
 */
int aim_setversions(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, 0x0017, 0x0000, NULL, 0);
        aim_putsnac(&fr->data, 0x0001, 0x0017, 0x0000, snacid);

        /*
         * Send only the 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);
                }
        }

        aim_tx_enqueue(sess, fr);

        return 0;
}

/* Host versions (group 1, subtype 0x18) */
static int hostversions(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        guint8 *versions;

        /* This is frivolous. (Thank you SmarterChild.) */
        aim_bstream_empty(bs); /* == vercount * 4 */
        versions = aimbs_getraw(bs, aim_bstream_empty(bs));
        g_free(versions);

        /*
         * Now request rates.
         */
        aim_reqrates(sess, rx->conn);

        return 1;
}

/* 
 * Subtype 0x001e - Extended Status
 *
 * Sets your ICQ status (available, away, do not disturb, etc.)
 *
 * These are the same TLVs seen in user info.  You can 
 * also set 0x0008 and 0x000c.
 */
int aim_setextstatus(aim_session_t *sess, aim_conn_t *conn, guint32 status)
{
        aim_frame_t *fr;
        aim_snacid_t snacid;
        aim_tlvlist_t *tl = NULL;
        guint32 data;
        struct im_connection *ic = sess ? sess->aux_data : NULL;

        data = AIM_ICQ_STATE_HIDEIP | status; /* yay for error checking ;^) */
        
        if (ic && set_getbool(&ic->acc->set, "web_aware"))
                data |= AIM_ICQ_STATE_WEBAWARE;

        aim_addtlvtochain32(&tl, 0x0006, data); /* tlvlen */

        if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x02, 10 + 8)))
                return -ENOMEM;

        snacid = aim_cachesnac(sess, 0x0001, 0x001e, 0x0000, NULL, 0);
        aim_putsnac(&fr->data, 0x0001, 0x001e, 0x0000, snacid);
        
        aim_writetlvchain(&fr->data, &tl);
        aim_freetlvchain(&tl);
        
        aim_tx_enqueue(sess, fr);

        return 0;
}

/*
 * Starting this past week (26 Mar 2001, say), AOL has started sending
 * this nice little extra SNAC.  AFAIK, it has never been used until now.
 *
 * The request contains eight bytes.  The first four are an offset, the
 * second four are a length.
 *
 * The offset is an offset into aim.exe when it is mapped during execution
 * on Win32.  So far, AOL has only been requesting bytes in static regions
 * of memory.  (I won't put it past them to start requesting data in
 * less static regions -- regions that are initialized at run time, but still
 * before the client recieves this request.)
 *
 * When the client recieves the request, it adds it to the current ds
 * (0x00400000) and dereferences it, copying the data into a buffer which
 * it then runs directly through the MD5 hasher.  The 16 byte output of
 * the hash is then sent back to the server.
 *
 * If the client does not send any data back, or the data does not match
 * the data that the specific client should have, the client will get the
 * following message from "AOL Instant Messenger":
 *    "You have been disconnected from the AOL Instant Message Service (SM) 
 *     for accessing the AOL network using unauthorized software.  You can
 *     download a FREE, fully featured, and authorized client, here 
 *     http://www.aol.com/aim/download2.html"
 * The connection is then closed, recieving disconnect code 1, URL
 * http://www.aim.aol.com/errors/USER_LOGGED_OFF_NEW_LOGIN.html.  
 *
 * Note, however, that numerous inconsistencies can cause the above error, 
 * not just sending back a bad hash.  Do not immediatly suspect this code
 * if you get disconnected.  AOL and the open/free software community have
 * played this game for a couple years now, generating the above message
 * on numerous ocassions.
 *
 * Anyway, neener.  We win again.
 *
 */
/* Client verification (group 1, subtype 0x1f) */
static int memrequest(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{
        aim_rxcallback_t userfunc;
        guint32 offset, len;
        aim_tlvlist_t *list;
        char *modname;

        offset = aimbs_get32(bs);
        len = aimbs_get32(bs);
        list = aim_readtlvchain(bs);

        modname = aim_gettlv_str(list, 0x0001, 1);

        if ((userfunc = aim_callhandler(sess, rx->conn, snac->family, snac->subtype)))
                return userfunc(sess, rx, offset, len, modname);

        g_free(modname);
        aim_freetlvchain(&list);

        return 0;
}

/* Client verification reply (group 1, subtype 0x20) */
int aim_sendmemblock(aim_session_t *sess, aim_conn_t *conn, guint32 offset, guint32 len, const guint8 *buf, guint8 flag)
{
        aim_frame_t *fr;
        aim_snacid_t snacid;

        if (!sess || !conn)
                return -EINVAL;

        if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x02, 10+2+16)))
                return -ENOMEM;

        snacid = aim_cachesnac(sess, 0x0001, 0x0020, 0x0000, NULL, 0);

        aim_putsnac(&fr->data, 0x0001, 0x0020, 0x0000, snacid);
        aimbs_put16(&fr->data, 0x0010); /* md5 is always 16 bytes */

        if ((flag == AIM_SENDMEMBLOCK_FLAG_ISHASH) && buf && (len == 0x10)) { /* we're getting a hash */

                aimbs_putraw(&fr->data, buf, 0x10); 

        } else if (buf && (len > 0)) { /* use input buffer */
                md5_state_t state;
                md5_byte_t digest[0x10];

                md5_init(&state);       
                md5_append(&state, (const md5_byte_t *)buf, len);
                md5_finish(&state, digest);

                aimbs_putraw(&fr->data, (guint8 *)digest, 0x10);

        } else if (len == 0) { /* no length, just hash NULL (buf is optional) */
                md5_state_t state;
                guint8 nil = '\0';
                md5_byte_t digest[0x10];

                /*
                 * These MD5 routines are stupid in that you have to have
                 * at least one append.  So thats why this doesn't look 
                 * real logical.
                 */
                md5_init(&state);
                md5_append(&state, (const md5_byte_t *)&nil, 0);
                md5_finish(&state, digest);

                aimbs_putraw(&fr->data, (guint8 *)digest, 0x10);

        } else {

                /* 
                 * This data is correct for AIM 3.5.1670.
                 *
                 * Using these blocks is as close to "legal" as you can get
                 * without using an AIM binary.
                 *
                 */
                if ((offset == 0x03ffffff) && (len == 0x03ffffff)) {

#if 1 /* with "AnrbnrAqhfzcd" */
                        aimbs_put32(&fr->data, 0x44a95d26);
                        aimbs_put32(&fr->data, 0xd2490423);
                        aimbs_put32(&fr->data, 0x93b8821f);
                        aimbs_put32(&fr->data, 0x51c54b01);
#else /* no filename */
                        aimbs_put32(&fr->data, 0x1df8cbae);
                        aimbs_put32(&fr->data, 0x5523b839);
                        aimbs_put32(&fr->data, 0xa0e10db3);
                        aimbs_put32(&fr->data, 0xa46d3b39);
#endif

/* len can't be 0 here anyway...
                } else if ((offset == 0x00001000) && (len == 0x00000000)) {

                        aimbs_put32(&fr->data, 0xd41d8cd9);
                        aimbs_put32(&fr->data, 0x8f00b204);
                        aimbs_put32(&fr->data, 0xe9800998);
                        aimbs_put32(&fr->data, 0xecf8427e);
*/
                } else
                        imcb_error(sess->aux_data, "Warning: unknown hash request");

        }

        aim_tx_enqueue(sess, fr);

        return 0;
}

static int snachandler(aim_session_t *sess, aim_module_t *mod, aim_frame_t *rx, aim_modsnac_t *snac, aim_bstream_t *bs)
{

        if (snac->subtype == 0x0003)
                return hostonline(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x0005)
                return redirect(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x0007)
                return rateresp(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x000a)
                return ratechange(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x000b)
                return serverpause(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x000d)
                return serverresume(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x000f)
                return selfinfo(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x0010)
                return evilnotify(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x0012)
                return migrate(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x0013)
                return motd(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x0018)
                return hostversions(sess, mod, rx, snac, bs);
        else if (snac->subtype == 0x001f)
                return memrequest(sess, mod, rx, snac, bs);

        return 0;
}

int general_modfirst(aim_session_t *sess, aim_module_t *mod)
{

        mod->family = 0x0001;
        mod->version = 0x0003;
        mod->toolid = 0x0110;
        mod->toolversion = 0x0629;
        mod->flags = 0;
        strncpy(mod->name, "general", sizeof(mod->name));
        mod->snachandler = snachandler;

        return 0;
}