source: protocols/oscar/conn.c @ 650d2b4

/*
 * conn.c
 *
 * Does all this gloriously nifty connection handling stuff...
 *
 */

#include <aim.h> 
#include "sock.h"

static int aim_logoff(aim_session_t *sess);

/*
 * In OSCAR, every connection has a set of SNAC groups associated
 * with it.  These are the groups that you can send over this connection
 * without being guarenteed a "Not supported" SNAC error.  
 *
 * The grand theory of things says that these associations transcend 
 * what libfaim calls "connection types" (conn->type).  You can probably
 * see the elegance here, but since I want to revel in it for a bit, you 
 * get to hear it all spelled out.
 *
 * So let us say that you have your core BOS connection running.  One
 * of your modules has just given you a SNAC of the group 0x0004 to send
 * you.  Maybe an IM destined for some twit in Greenland.  So you start
 * at the top of your connection list, looking for a connection that 
 * claims to support group 0x0004.  You find one.  Why, that neat BOS
 * connection of yours can do that.  So you send it on its way.
 *
 * Now, say, that fellow from Greenland has friends and they all want to
 * meet up with you in a lame chat room.  This has landed you a SNAC
 * in the family 0x000e and you have to admit you're a bit lost.  You've
 * searched your connection list for someone who wants to make your life
 * easy and deliver this SNAC for you, but there isn't one there.
 *
 * Here comes the good bit.  Without even letting anyone know, particularly
 * the module that decided to send this SNAC, and definitly not that twit
 * in Greenland, you send out a service request.  In this request, you have
 * marked the need for a connection supporting group 0x000e.  A few seconds
 * later, you receive a service redirect with an IP address and a cookie in
 * it.  Great, you say.  Now I have something to do.  Off you go, making
 * that connection.  One of the first things you get from this new server
 * is a message saying that indeed it does support the group you were looking
 * for.  So you continue and send rate confirmation and all that.  
 * 
 * Then you remember you had that SNAC to send, and now you have a means to
 * do it, and you do, and everyone is happy.  Except the Greenlander, who is
 * still stuck in the bitter cold.
 *
 * Oh, and this is useful for building the Migration SNACs, too.  In the
 * future, this may help convince me to implement rate limit mitigation
 * for real.  We'll see.
 *
 * Just to make me look better, I'll say that I've known about this great
 * scheme for quite some time now.  But I still haven't convinced myself
 * to make libfaim work that way.  It would take a fair amount of effort,
 * and probably some client API changes as well.  (Whenever I don't want
 * to do something, I just say it would change the client API.  Then I 
 * instantly have a couple of supporters of not doing it.)
 *
 * Generally, addgroup is only called by the internal handling of the
 * server ready SNAC.  So if you want to do something before that, you'll
 * have to be more creative.  That is done rather early, though, so I don't
 * think you have to worry about it.  Unless you're me.  I care deeply
 * about such inane things.
 *
 */
void aim_conn_addgroup(aim_conn_t *conn, guint16 group)
{
        aim_conn_inside_t *ins = (aim_conn_inside_t *)conn->inside;
        struct snacgroup *sg;

        if (!(sg = g_malloc(sizeof(struct snacgroup))))
                return;

        sg->group = group;

        sg->next = ins->groups;
        ins->groups = sg;

        return;
}

aim_conn_t *aim_conn_findbygroup(aim_session_t *sess, guint16 group)
{
        aim_conn_t *cur;

        for (cur = sess->connlist; cur; cur = cur->next) {
                aim_conn_inside_t *ins = (aim_conn_inside_t *)cur->inside;
                struct snacgroup *sg;

                for (sg = ins->groups; sg; sg = sg->next) {
                        if (sg->group == group)
                                return cur;
                }
        }

        return NULL;
}

static void connkill_snacgroups(struct snacgroup **head)
{
        struct snacgroup *sg;

        for (sg = *head; sg; ) {
                struct snacgroup *tmp;

                tmp = sg->next;
                g_free(sg);
                sg = tmp;
        }

        *head = NULL;

        return;
}

static void connkill_rates(struct rateclass **head)
{
        struct rateclass *rc;

        for (rc = *head; rc; ) {
                struct rateclass *tmp;
                struct snacpair *sp;

                tmp = rc->next;

                for (sp = rc->members; sp; ) {
                        struct snacpair *tmpsp;

                        tmpsp = sp->next;
                        g_free(sp);
                        sp = tmpsp;
                }
                g_free(rc);

                rc = tmp;
        }

        *head = NULL;

        return;
}

static void connkill_real(aim_session_t *sess, aim_conn_t **deadconn)
{

        aim_rxqueue_cleanbyconn(sess, *deadconn);
        aim_tx_cleanqueue(sess, *deadconn);

        if ((*deadconn)->fd != -1) 
                aim_conn_close(*deadconn);

        /*
         * XXX ->priv should never be touched by the library. I know
         * it used to be, but I'm getting rid of all that.  Use
         * ->internal instead.
         */
        if ((*deadconn)->priv)
                g_free((*deadconn)->priv);

        /*
         * This will free ->internal if it necessary...
         */
        if ((*deadconn)->type == AIM_CONN_TYPE_CHAT)
                aim_conn_kill_chat(sess, *deadconn);

        if ((*deadconn)->inside) {
                aim_conn_inside_t *inside = (aim_conn_inside_t *)(*deadconn)->inside;

                connkill_snacgroups(&inside->groups);
                connkill_rates(&inside->rates);

                g_free(inside);
        }

        g_free(*deadconn);
        *deadconn = NULL;

        return;
}

/**
 * aim_connrst - Clears out connection list, killing remaining connections.
 * @sess: Session to be cleared
 *
 * Clears out the connection list and kills any connections left.
 *
 */
static void aim_connrst(aim_session_t *sess)
{

        if (sess->connlist) {
                aim_conn_t *cur = sess->connlist, *tmp;

                while (cur) {
                        tmp = cur->next;
                        aim_conn_close(cur);
                        connkill_real(sess, &cur);
                        cur = tmp;
                }
        }

        sess->connlist = NULL;

        return;
}

/**
 * aim_conn_init - Reset a connection to default values.
 * @deadconn: Connection to be reset
 *
 * Initializes and/or resets a connection structure.
 *
 */
static void aim_conn_init(aim_conn_t *deadconn)
{

        if (!deadconn)
                return;

        deadconn->fd = -1;
        deadconn->subtype = -1;
        deadconn->type = -1;
        deadconn->seqnum = 0;
        deadconn->lastactivity = 0;
        deadconn->forcedlatency = 0;
        deadconn->handlerlist = NULL;
        deadconn->priv = NULL;
        memset(deadconn->inside, 0, sizeof(aim_conn_inside_t));

        return;
}

/**
 * aim_conn_getnext - Gets a new connection structure.
 * @sess: Session
 *
 * Allocate a new empty connection structure.
 *
 */
static aim_conn_t *aim_conn_getnext(aim_session_t *sess)
{
        aim_conn_t *newconn;

        if (!(newconn = g_new0(aim_conn_t,1)))  
                return NULL;

        if (!(newconn->inside = g_new0(aim_conn_inside_t,1))) {
                g_free(newconn);
                return NULL;
        }

        aim_conn_init(newconn);

        newconn->next = sess->connlist;
        sess->connlist = newconn;

        return newconn;
}

/**
 * aim_conn_kill - Close and free a connection.
 * @sess: Session for the connection
 * @deadconn: Connection to be freed
 *
 * Close, clear, and free a connection structure. Should never be
 * called from within libfaim.
 *
 */
void aim_conn_kill(aim_session_t *sess, aim_conn_t **deadconn)
{
        aim_conn_t *cur, **prev;

        if (!deadconn || !*deadconn)    
                return;

        for (prev = &sess->connlist; (cur = *prev); ) {
                if (cur == *deadconn) {
                        *prev = cur->next;
                        break;
                }
                prev = &cur->next;
        }

        if (!cur)
                return; /* oops */

        connkill_real(sess, &cur);

        return;
}

/**
 * aim_conn_close - Close a connection
 * @deadconn: Connection to close
 *
 * Close (but not free) a connection.
 *
 * This leaves everything untouched except for clearing the 
 * handler list and setting the fd to -1 (used to recognize
 * dead connections).  It will also remove cookies if necessary.
 *
 */
void aim_conn_close(aim_conn_t *deadconn)
{

        if (deadconn->fd >= 3)
                closesocket(deadconn->fd);
        deadconn->fd = -1;
        if (deadconn->handlerlist)
                aim_clearhandlers(deadconn);

        return;
}

/**
 * aim_getconn_type - Find a connection of a specific type
 * @sess: Session to search
 * @type: Type of connection to look for
 *
 * Searches for a connection of the specified type in the 
 * specified session.  Returns the first connection of that
 * type found.
 *
 * XXX except for RENDEZVOUS, all uses of this should be removed and
 * use aim_conn_findbygroup() instead.
 */
aim_conn_t *aim_getconn_type(aim_session_t *sess, int type)
{
        aim_conn_t *cur;

        for (cur = sess->connlist; cur; cur = cur->next) {
                if ((cur->type == type) && 
                                !(cur->status & AIM_CONN_STATUS_INPROGRESS))
                        break;
        }

        return cur;
}

aim_conn_t *aim_getconn_type_all(aim_session_t *sess, int type)
{
        aim_conn_t *cur;

        for (cur = sess->connlist; cur; cur = cur->next) {
                if (cur->type == type)
                        break;
        }

        return cur;
}

/**
 * aim_newconn - Open a new connection
 * @sess: Session to create connection in
 * @type: Type of connection to create
 * @dest: Host to connect to (in "host:port" syntax)
 *
 * Opens a new connection to the specified dest host of specified
 * type, using the proxy settings if available.  If @host is %NULL,
 * the connection is allocated and returned, but no connection 
 * is made.
 *
 * FIXME: Return errors in a more sane way.
 *
 */
aim_conn_t *aim_newconn(aim_session_t *sess, int type, const char *dest)
{
        aim_conn_t *connstruct;
        guint16 port = AIM_LOGIN_PORT;
        char *host;
        int i;

        if (!(connstruct = aim_conn_getnext(sess)))
                return NULL;

        connstruct->sessv = (void *)sess;
        connstruct->type = type;

        if (!dest) { /* just allocate a struct */
                connstruct->fd = -1;
                connstruct->status = 0;
                return connstruct;
        }

        /* 
         * As of 23 Jul 1999, AOL now sends the port number, preceded by a 
         * colon, in the BOS redirect.  This fatally breaks all previous 
         * libfaims.  Bad, bad AOL.
         *
         * We put this here to catch every case. 
         *
         */

        for(i = 0; i < (int)strlen(dest); i++) {
                if (dest[i] == ':') {
                        port = atoi(&(dest[i+1]));
                        break;
                }
        }

        host = (char *)g_malloc(i+1);
        strncpy(host, dest, i);
        host[i] = '\0';

        connstruct->fd = proxy_connect(host, port, NULL, NULL);

        g_free(host);

        return connstruct;
}

/**
 * aim_conn_setlatency - Set a forced latency value for connection
 * @conn: Conn to set latency for
 * @newval: Number of seconds to force between transmits
 *
 * Causes @newval seconds to be spent between transmits on a connection.
 *
 * This is my lame attempt at overcoming not understanding the rate
 * limiting. 
 *
 * XXX: This should really be replaced with something that scales and
 * backs off like the real rate limiting does.
 *
 */
int aim_conn_setlatency(aim_conn_t *conn, int newval)
{

        if (!conn)
                return -1;

        conn->forcedlatency = newval;
        conn->lastactivity = 0; /* reset this just to make sure */

        return 0;
}

/**
 * aim_session_init - Initializes a session structure
 * @sess: Session to initialize
 * @flags: Flags to use. Any of %AIM_SESS_FLAGS %OR'd together.
 * @debuglevel: Level of debugging output (zero is least)
 *
 * Sets up the initial values for a session.
 *
 */
void aim_session_init(aim_session_t *sess, guint32 flags, int debuglevel)
{

        if (!sess)
                return;

        memset(sess, 0, sizeof(aim_session_t));
        aim_connrst(sess);
        sess->queue_outgoing = NULL;
        sess->queue_incoming = NULL;
        aim_initsnachash(sess);
        sess->msgcookies = NULL;
        sess->snacid_next = 0x00000001;

        sess->flags = 0;

        sess->modlistv = NULL;

        sess->ssi.received_data = 0;
        sess->ssi.waiting_for_ack = 0;
        sess->ssi.holding_queue = NULL;
        sess->ssi.revision = 0;
        sess->ssi.items = NULL;
        sess->ssi.timestamp = (time_t)0;

        sess->locate.userinfo = NULL;
        sess->locate.torequest = NULL;
        sess->locate.requested = NULL;
        sess->locate.waiting_for_response = FALSE;

        sess->icq_info = NULL;
        sess->authinfo = NULL;
        sess->emailinfo = NULL;
        sess->oft_info = NULL;


        /*
         * Default to SNAC login unless XORLOGIN is explicitly set.
         */
        if (!(flags & AIM_SESS_FLAGS_XORLOGIN))
                sess->flags |= AIM_SESS_FLAGS_SNACLOGIN;
        sess->flags |= flags;

        /*
         * This must always be set.  Default to the queue-based
         * version for back-compatibility.  
         */
        aim_tx_setenqueue(sess, AIM_TX_QUEUED, NULL);


        /*
         * Register all the modules for this session...
         */
        aim__registermodule(sess, misc_modfirst); /* load the catch-all first */
        aim__registermodule(sess, general_modfirst);
        aim__registermodule(sess, locate_modfirst);
        aim__registermodule(sess, buddylist_modfirst);
        aim__registermodule(sess, msg_modfirst);
        aim__registermodule(sess, admin_modfirst);
        aim__registermodule(sess, bos_modfirst);
        aim__registermodule(sess, search_modfirst);
        aim__registermodule(sess, stats_modfirst);
        aim__registermodule(sess, chatnav_modfirst);
        aim__registermodule(sess, chat_modfirst);
        /* missing 0x0f - 0x12 */
        aim__registermodule(sess, ssi_modfirst);
        /* missing 0x14 */
        aim__registermodule(sess, icq_modfirst);
        /* missing 0x16 */
        aim__registermodule(sess, auth_modfirst);

        return;
}

/**
 * aim_session_kill - Deallocate a session
 * @sess: Session to kill
 *
 */
void aim_session_kill(aim_session_t *sess)
{
        aim_cleansnacs(sess, -1);

        aim_logoff(sess);

        aim__shutdownmodules(sess);

        return;
}

/*
 * XXX this is nearly as ugly as proxyconnect().
 */
int aim_conn_completeconnect(aim_session_t *sess, aim_conn_t *conn)
{
        fd_set fds, wfds;
        struct timeval tv;
        int res, error = ETIMEDOUT;
        aim_rxcallback_t userfunc;

        if (!conn || (conn->fd == -1))
                return -1;

        if (!(conn->status & AIM_CONN_STATUS_INPROGRESS))
                return -1;

        FD_ZERO(&fds);
        FD_SET(conn->fd, &fds);
        FD_ZERO(&wfds);
        FD_SET(conn->fd, &wfds);
        tv.tv_sec = 0;
        tv.tv_usec = 0;

        if ((res = select(conn->fd+1, &fds, &wfds, NULL, &tv)) == -1) {
                error = errno;
                aim_conn_close(conn);
                errno = error;
                return -1;
        } else if (res == 0) {
                return 0; /* hasn't really completed yet... */
        } 

        if (FD_ISSET(conn->fd, &fds) || FD_ISSET(conn->fd, &wfds)) {
                unsigned int len = sizeof(error);

                if (getsockopt(conn->fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0)
                        error = errno;
        }

        if (error) {
                aim_conn_close(conn);
                errno = error;
                return -1;
        }

        sock_make_blocking(conn->fd);

        conn->status &= ~AIM_CONN_STATUS_INPROGRESS;

        if ((userfunc = aim_callhandler(sess, conn, AIM_CB_FAM_SPECIAL, AIM_CB_SPECIAL_CONNCOMPLETE)))
                userfunc(sess, NULL, conn);

        /* Flush out the queues if there was something waiting for this conn  */
        aim_tx_flushqueue(sess);

        return 0;
}

aim_session_t *aim_conn_getsess(aim_conn_t *conn)
{

        if (!conn)
                return NULL;

        return (aim_session_t *)conn->sessv;
}

/*
 * aim_logoff()
 *
 * Closes -ALL- open connections.
 *
 */
static int aim_logoff(aim_session_t *sess)
{

        aim_connrst(sess);  /* in case we want to connect again */

        return 0;

}

/*
 * aim_flap_nop()
 *
 * No-op.  WinAIM 4.x sends these _every minute_ to keep
 * the connection alive.  
 */
int aim_flap_nop(aim_session_t *sess, aim_conn_t *conn)
{
        aim_frame_t *fr;

        if (!(fr = aim_tx_new(sess, conn, AIM_FRAMETYPE_FLAP, 0x05, 0)))
                return -ENOMEM;

        aim_tx_enqueue(sess, fr);

        return 0;
}