⟦036036dec⟧

TextFile

/* conn_select.c - tidy connection mesh and choose next activity */

#ifndef lint
static char *rcsid = "$Header: /f/osi/quipu/RCS/conn_select.c,v 6.0 89/03/18 23:41:10 mrose Rel $";
#endif

/*
 * $Header: /f/osi/quipu/RCS/conn_select.c,v 6.0 89/03/18 23:41:10 mrose Rel $
 *
 *
 * $Log:	conn_select.c,v $
 * Revision 6.0  89/03/18  23:41:10  mrose
 * Release 5.0
 * 
 */

/*
 *                                NOTICE
 *
 *    Acquisition, use, and distribution of this module and related
 *    materials are subject to the restrictions of a license agreement.
 *    Consult the Preface in the User's Manual for the full terms of
 *    this agreement.
 *
 */


#include "quipu/util.h"
#include "quipu/connection.h"

extern LLog * log_dsap;
extern time_t	conn_timeout;
extern time_t	time();

/*
* New strategy is to,
* do any activity for a connection with state INIT,
* extract any connection with state FAIL,
* select any activity for the DSA with the following priority:
*       priority as given for state OPEN,
*       priority plus highest priority for state EXIT.
*/

int             conn_select(act_p)
register        struct activity **act_p;
{
    int                   priority;
    int                   action;
    struct connection   * cn;
    struct connection   **cn_last;
    struct activity     * tk;
    struct activity     * on;
    time_t		  time_now;
    char		  no_block;

    DLOG (log_dsap,LLOG_TRACE, ("conn_select"));
    /*
    * Default action is to await network activity.
    * Active read and write ad's are set as the connection mesh is scanned.
    */
    no_block = FALSE;
    action = ACTIVITY_NET_WAIT;
    priority = 0;
    (* act_p) = NULLACTIVITY;
    id_st.nads = 0;
    FD_ZERO(&id_st.iads);
    FD_ZERO(&id_st.wads);
    cn_last = &(id_st.connlist);
    time_now = time((time_t *) 0);

    /*
    * Check existing connections for higher priority action.
    * Set up association descriptors.
    */
    for(cn=id_st.connlist; cn!=NULLCONN; cn=(*cn_last))
    {
	DLOG (log_dsap,LLOG_DEBUG, ("Checking cn with ad = %d", cn->cn_ad));
	conn_log(cn);

	if(cn->cn_state == CN_STATE_INIT)
	{
	    cn->cn_last_used = time_now;
	    if(cn->cn_init_act.ia_class == ACTIVITY_NET_SEND)
	    {
		net_send_init_request(cn);
	    }

	    if(cn->cn_init_act.ia_class == ACTIVITY_NET_WAIT)
	    {
		if((cn->cn_tasklist != NULLACTIVITY)
		  && (cn->cn_tasklist->act_class == ACTIVITY_COLLATE))
		{ /* Remote compare in bind needs collating */
		    dsa_collate(cn->cn_tasklist);

		    if(cn->cn_init_act.ia_class == ACTIVITY_COLLATE)
		    { /* Remote compare completed */
			dsa_bind_collate(cn);
		    }
		    else
		    { /* Do not block when compare has been referred */
			no_block = TRUE;
		    }
		}
	    }
	}

	if(cn->cn_state == CN_STATE_OPEN)
	{
	    struct activity	* next_on;

	    for(tk=cn->cn_tasklist; tk!=NULLACTIVITY; tk=tk->tk_next)
	    {
		if(tk->act_class == ACTIVITY_NET_WAIT)
		    continue;
		if(tk->act_class == ACTIVITY_NET_SEND)
		{
		    net_send_open_response(tk);
		    continue;
		}
		if(tk->act_prio > priority)
		{
		    (*act_p) = tk;
		    action = tk->act_class;
		    priority = tk->act_prio;
		}
	    }

	    for(on=cn->cn_operlist; on!=NULLACTIVITY; on=next_on)
	    {
		next_on = on->on_next_conn;
		if(on->on_task == NULLACTIVITY)
		{
		    LLOG(log_dsap, LLOG_DEBUG, ("Watch out for memory twists"));
		    oper_conn_extract(on);
		    act_free(on);
		}
		else
		{
		    if(on->act_class == ACTIVITY_NET_SEND)
		    {
			net_send_ro_invoke(on);
		    }
		}
	    }

	    if(cn->cn_initiator == INITIATED_BY_THIS)
	    {
		if((cn->cn_operlist == NULLACTIVITY) &&
		   (cn->cn_tasklist == NULLACTIVITY))
		{
		    /*
		    *  Should do some timing out here with hooks so that the
		    *  network doesn't block while a connection is timing out.
		    */
		    no_block = TRUE;
		    LLOG(log_dsap, LLOG_TRACE, ("timeout = %ld, last_used = %ld, time_now = %ld", conn_timeout, cn->cn_last_used, time_now));
		    if((time_now - cn->cn_last_used) > conn_timeout)
		    {
			LLOG(log_dsap, LLOG_NOTICE, ("Timing out connection"));
			cn->cn_state = CN_STATE_EXIT;
			cn->cn_exit_act.exit_act_class = ACTIVITY_DSA_WORK;
		    }
		}
		else
		{
		    cn->cn_last_used = time_now;
		}
	    }
	}

	if(cn->cn_state == CN_STATE_EXIT)
	{
	    for(tk=cn->cn_tasklist; tk!=NULLACTIVITY; tk=tk->tk_next)
	    {
		if(tk->act_class == ACTIVITY_NET_WAIT)
		    continue;
		if(tk->act_class == ACTIVITY_NET_SEND)
		{
		    net_send_open_response(tk);
		    continue;
		}
		if((tk->act_prio + DSA_MAX_PRIO) > priority)
		{
		    (*act_p) = tk;
		    action = tk->act_class;
		    priority = tk->act_prio + DSA_MAX_PRIO;
		}
	    }

	    if(cn->cn_tasklist == NULLACTIVITY)
	    {
		if(cn->cn_exit_act.exit_act_class == ACTIVITY_DSA_WORK)
		{
		    if(cn->cn_initiator == INITIATED_BY_THIS)
			dsa_work_exit_request(cn);
		    else
			dsa_work_exit_response(cn);
		}

		if(cn->cn_initiator == INITIATED_BY_THIS)
		    net_send_ac_finish(cn);
		else
		    net_send_ac_exit(cn);
	    }
	}

	if(cn->cn_state == CN_STATE_FAIL)
	{
	    for(on=cn->cn_operlist; on!=NULLACTIVITY; on=on->on_next_conn)
	    {
		on->act_class = ACTIVITY_COLLATE;
	        on->act_type = ACT_TYPE_RESP;
		on->act_resp.resp_type = RESP_TYPE_REJ;
		if(on->on_task == NULLACTIVITY)
		{
		    DLOG(log_dsap, LLOG_DEBUG, ("Task already collated!"));
		}
		else
		{
		    on->on_task->act_class = ACTIVITY_COLLATE;
		}
	    }
	    (*cn_last) = cn->cn_next;
	    if(cn->cn_ad != 0)
		net_send_abort(cn);
	    conn_extract(cn);
	}
	else
	{
	    cn_last = &(cn->cn_next);
	    if((cn->cn_state == CN_STATE_INIT)
		&& (cn->cn_init_act.ia_class == ACTIVITY_NET_WAIT)
		&& (cn->cn_init_act.ia_type == ACT_TYPE_REQ))
	    {
		FD_SET(cn->cn_ad, &id_st.wads);
	    }
	    else
	    {
	        FD_SET(cn->cn_ad, &id_st.iads);
	    }
	    if(id_st.nads <= cn->cn_ad)
		id_st.nads = cn->cn_ad + 1;
	}
    } /* for each connection */

    if((priority == 0) && no_block)
    { /* Poll the network unless something else comes up */
	action = ACTIVITY_NET_WAIT;
	(*act_p) = (struct activity *) -1;
    }
    DLOG (log_dsap,LLOG_TRACE, ("Action selected: %d; has priority %d.", action, priority));
    return(action);
} /* conn_select() */
DataMuseum.dk

DKUUG/EUUG Conference tapes

⟦036036dec⟧ TextFile

Derivation

TextFile
