pri_event *pri_read_event(struct pri *pri)
{
        char buf[1024];
        int res;
        res = pri->read_func ? pri->read_func(pri, buf, sizeof(buf)) : 0;
        /* this check should be at some routine in q921.c */
        /* at least 4 bytes of Q921 and at check buf[4] for Q931 Network packet */
        if (res < 5 || ((int)buf[4] != 8)) {
                return NULL;
        }
        res = q931_read_event(pri, (q931_h*)(buf + 4), res - 4 - 2 /* remove 4 bytes of Q921 h and 2 of CRC */);
        if (res == -1) {
                return NULL;
        }
        if (res & Q931_RES_HAVEEVENT) {
                return &pri->ev;
        }
        return NULL;
}
 
/* here we trust receiving q931 only (no maintenance or anything else)*/
int q931_read_event(struct pri *ctrl, q931_h *h, int len)
{
        q931_mh *mh;
        q931_call *c;
        int cref;
        int missingmand;
 
        //q931_dump(ctrl, h, len, 0);
 
        mh = (q931_mh *)(h->contents + h->crlen);
 
        cref = q931_cr(h);
 
        c = q931_getcall(ctrl, cref & 0x7FFF);
        if (!c) {
                pri_error(ctrl, "Unable to locate call %d\n", cref);
                return -1;
        }
 
        if (prepare_to_handle_q931_message(ctrl, mh, c)) {
                return 0;
        }
 
        missingmand = 0;
        if (q931_process_ies(ctrl, h, len, mh, c, &missingmand)) {
                return -1;
        }
 
        return post_handle_q931_message(ctrl, mh, c, missingmand, 0);
}

        if (i->tappingpeer) {
                struct dahdi_confinfo dahdic = { 0, };
                /* create the mixing conference
                 * some DAHDI_SETCONF interface rules to keep in mind
                 * confno == -1 means create new conference with the given confmode
                 * confno and confmode == 0 means remove the channel from its conference */
                dahdic.chan = 0; /* means use current channel (the one the fd belongs to)*/
                dahdic.confno = -1; /* -1 means create new conference */
                dahdic.confmode = DAHDI_CONF_CONFMON | DAHDI_CONF_LISTENER | DAHDI_CONF_PSEUDO_LISTENER;
                fd = dahdi_open("/dev/dahdi/pseudo");
                if (fd < 0 || ioctl(fd, DAHDI_SETCONF, &dahdic)) {
                        ast_log(LOG_ERROR, "Unable to create dahdi conference for tapping\n");
                        ast_hangup(tmp);
                        i->owner = NULL;
                        return NULL;
                }
                i->tappingconf = dahdic.confno;
                i->tappingfd = fd;
 
                /* add both parties to the conference */
                dahdic.chan = 0;
                dahdic.confno = i->tappingconf;
                dahdic.confmode = DAHDI_CONF_CONF | DAHDI_CONF_TALKER;
                if (ioctl(i->subs[SUB_REAL].dfd, DAHDI_SETCONF, &dahdic)) {
                        ast_log(LOG_ERROR, "Unable to add chan to conference for tapping devices: %s\n", strerror(errno));
                        ast_hangup(tmp);
                        i->owner = NULL;
                        return NULL;
                }
                dahdic.chan = 0;
                dahdic.confno = i->tappingconf;
                dahdic.confmode = DAHDI_CONF_CONF | DAHDI_CONF_TALKER;
                if (ioctl(i->tappingpeer->subs[SUB_REAL].dfd, DAHDI_SETCONF, &dahdic)) {
                        ast_log(LOG_ERROR, "Unable to add peer chan to conference for tapping devices: %s\n", strerror(errno));
                        ast_hangup(tmp);
                        i->owner = NULL;
                        return NULL;
                }
                ast_log(LOG_DEBUG, "Created tapping conference %d with fd %d between dahdi chans %d and %d for ast channel %s\n",
                                i->tappingconf,
                                i->tappingfd,
                                i->channel,
                                i->tappingpeer->channel,
                                tmp->name);
                i->tappingpeer->owner = i->owner;
       }

                /* from now on, reading from the conference has the mix of both tapped channels, we can now launch the pbx thread */
                if (ast_pbx_start(c) != AST_PBX_SUCCESS) {
                        ast_log(LOG_ERROR, "Failed to launch PBX thread for passive channel %s\n", c->name);
                        ast_hangup(c);
                }
                break;

       /* if we have a tap peer we must read the mixed audio */
        if (p->tappingpeer) {
                /* passive channel reading */
                /* first read from the 2 involved dahdi channels just to consume their frames */
                res = read(p->subs[idx].dfd, readbuf, p->subs[idx].linear ? READ_SIZE * 2 : READ_SIZE);
                CHECK_READ_RESULT(res);
                res = read(p->tappingpeer->subs[idx].dfd, readbuf, p->subs[idx].linear ? READ_SIZE * 2 : READ_SIZE);
                CHECK_READ_RESULT(res);
                /* now read the mixed audio that will be returned to the core */
                res = read(p->tappingfd, readbuf, p->subs[idx].linear ? READ_SIZE * 2 : READ_SIZE);
        } else {
                /* no tapping peer, normal reading */
                res = read(p->subs[idx].dfd, readbuf, p->subs[idx].linear ? READ_SIZE * 2 : READ_SIZE);
        }

[from-pstn]
exten => s,1,Answer()
;exten => s,n,Dial(SIP/moy)
exten => s,n,Record(advanced-recording%d:wav)
exten => s,n,Hangup()
exten => _X.,1,Goto(s,1)