Ejemplo n.º 1
0
Archivo: res_mgr.go Proyecto: att/tegu
/*
	Executes as a goroutine to drive the reservation manager portion of tegu.
*/
func Res_manager( my_chan chan *ipc.Chmsg, cookie *string ) {

	var (
		inv	*Inventory
		msg	*ipc.Chmsg
		ckptd	string
		last_qcheck	int64 = 0			// time that the last queue check was made to set window
		last_chkpt	int64 = 0			// time that the last checkpoint was written
		retry_chkpt bool = false		// checkpoint needs to be retried because of a timing issue
		queue_gen_type = REQ_GEN_EPQMAP
		alt_table = DEF_ALT_TABLE		// table number where meta marking happens
		all_sys_up	bool = false;		// set when we receive the all_up message; some functions (chkpt) must wait for this
		hto_limit 	int = 3600 * 18		// OVS has a size limit to the hard timeout value, this caps it just under the OVS limit
		res_refresh	int64 = 0			// next time when we must force all reservations to refresh flow-mods (hto_limit nonzero)
		rr_rate		int = 3600			// refresh rate (1 hour)
		favour_v6 bool = true			// favour ipv6 addresses if a host has both defined.
	)

	super_cookie = cookie				// global for all methods

	rm_sheep = bleater.Mk_bleater( 0, os.Stderr )		// allocate our bleater and attach it to the master
	rm_sheep.Set_prefix( "res_mgr" )
	tegu_sheep.Add_child( rm_sheep )					// we become a child so that if the master vol is adjusted we'll react too

	p := cfg_data["default"]["queue_type"]				// lives in default b/c used by fq-mgr too
	if p != nil {
		if *p == "endpoint" {
			queue_gen_type = REQ_GEN_EPQMAP
		} else {
			queue_gen_type = REQ_GEN_QMAP
		}
	}

	p = cfg_data["default"]["alttable"]				// alt table for meta marking
	if p != nil {
		alt_table = clike.Atoi( *p )
	}

	p = cfg_data["default"]["favour_ipv6"]
	if p != nil {
		favour_v6 = *p == "true"
	}

	if cfg_data["resmgr"] != nil {
		cdp := cfg_data["resmgr"]["chkpt_dir"]
		if cdp == nil {
			ckptd = "/var/lib/tegu/resmgr"							// default directory and prefix
		} else {
			ckptd = *cdp + "/resmgr"							// add prefix to directory in config
		}

		p = cfg_data["resmgr"]["verbose"]
		if p != nil {
			rm_sheep.Set_level(  uint( clike.Atoi( *p ) ) )
		}

		/*
		p = cfg_data["resmgr"]["set_vlan"]
		if p != nil {
			set_vlan = *p == "true"
		}
		*/

		p = cfg_data["resmgr"]["super_cookie"]
		if p != nil {
			super_cookie = p
			rm_sheep.Baa( 1, "super-cookie was set from config file" )
		}

		p = cfg_data["resmgr"]["hto_limit"]					// if OVS or whatever has a max timeout we can ensure it's not surpassed
		if p != nil {
			hto_limit = clike.Atoi( *p )
		}

		p = cfg_data["resmgr"]["res_refresh"]				// rate that reservations are refreshed if hto_limit is non-zero
		if p != nil {
			rr_rate = clike.Atoi( *p )
			if rr_rate < 900 {
				if rr_rate < 120 {
					rm_sheep.Baa( 0, "NOTICE: reservation refresh rate in config is insanely low (%ds) and was changed to 1800s", rr_rate )
					rr_rate = 1800
				} else {
					rm_sheep.Baa( 0, "NOTICE: reservation refresh rate in config is too low: %ds", rr_rate )
				}
			}
		}
	}

	send_meta_counter := 200;										// send meta f-mods only now and again
	rm_sheep.Baa( 1, "ovs table number %d used for metadata marking", alt_table )

	res_refresh = time.Now().Unix() + int64( rr_rate )				// set first refresh in an hour (ignored if hto_limit not set
	inv = Mk_inventory( )
	inv.chkpt = chkpt.Mk_chkpt( ckptd, 10, 90 )

	last_qcheck = time.Now().Unix()

	tkl_ch := make( chan *ipc.Chmsg, 5 )								// special, short buffer, channel for tickles allows 5 to queue before blocking sender
	tklr.Add_spot( 2, tkl_ch, REQ_PUSH, nil, ipc.FOREVER )				// push reservations to agent just before they go live
	tklr.Add_spot( 1, tkl_ch, REQ_SETQUEUES, nil, ipc.FOREVER )			// drives us to see if queues need to be adjusted
	tklr.Add_spot( 5, tkl_ch, REQ_RTRY_CHKPT, nil, ipc.FOREVER )		// ensures that we retried any missed checkpoints
	tklr.Add_spot( 60, tkl_ch, REQ_VET_RETRY, nil, ipc.FOREVER )		// run the retry queue if it has size

	go rm_lookup( rmgrlu_ch, inv )

	rm_sheep.Baa( 3, "res_mgr is running  %x", my_chan )
	for {
		select {									// select next ready message on either channel
			case msg = <- tkl_ch:					// msg available on tickle channel
				msg.State = nil						// nil state is OK, no error
				my_chan <- msg;						// just pass it through; tkl_ch has a small buffer (blocks quickly) and this prevents filling the main queue w/ tickles if we get busy	

			case msg = <- my_chan:					// process message from the main channel
				rm_sheep.Baa( 3, "processing message: %d", msg.Msg_type )
				switch msg.Msg_type {
					case REQ_NOOP:			// just ignore

					case REQ_ADD:
						msg.State = inv.Add_res( msg.Req_data )			// add will determine the pledge type and do the right thing
						msg.Response_data = nil


					case REQ_ALLUP:			// signals that all initialisation is complete (chkpting etc. can go)
						all_sys_up = true
						// periodic checkpointing turned off with the introduction of tegu_ha
						//tklr.Add_spot( 180, my_chan, REQ_CHKPT, nil, ipc.FOREVER )		// tickle spot to drive us every 180 seconds to checkpoint

					case REQ_RTRY_CHKPT:									// called to attempt to send a queued checkpoint request
						if all_sys_up {
							if retry_chkpt {
								rm_sheep.Baa( 3, "invoking checkpoint (retry)" )
								retry_chkpt, last_chkpt = inv.write_chkpt( last_chkpt )
							}
						}

					case REQ_CHKPT:											// external thread has requested checkpoint
						if all_sys_up {
							rm_sheep.Baa( 3, "invoking checkpoint" )
							retry_chkpt, last_chkpt = inv.write_chkpt( last_chkpt )
						}

					case REQ_DEL:											// user initiated delete -- requires cookie
						data := msg.Req_data.( []*string )					// assume pointers to name and cookie
						if data[0] != nil  &&  *data[0] == "all" {
							inv.Del_all_res( data[1] )
							msg.State = nil
						} else {
							msg.State = inv.Del_res( data[0], data[1] )
						}

						inv.push_reservations( my_chan, alt_table, int64( hto_limit ), favour_v6 )			// must force a push to push augmented (shortened) reservations
						msg.Response_data = nil

					case REQ_DUPCHECK:
						if msg.Req_data != nil {
							msg.Response_data, msg.State = inv.dup_check(  msg.Req_data.( *gizmos.Pledge ) )
						}

					case REQ_GET:											// user initiated get -- requires cookie
						data := msg.Req_data.( []*string )					// assume pointers to name and cookie
						msg.Response_data, msg.State = inv.Get_res( data[0], data[1] )

					case REQ_LIST:											// list reservations	(for a client)
						msg.Response_data, msg.State = inv.res2json( )

					case REQ_LOAD:								// load from a checkpoint file
						data := msg.Req_data.( *string )		// assume pointers to name and cookie
						msg.State = inv.load_chkpt( data )
						msg.Response_data = nil
						rm_sheep.Baa( 1, "checkpoint file loaded" )

					case REQ_PAUSE:
						msg.State = nil							// right now this cannot fail in ways we know about
						msg.Response_data = ""
						inv.pause_on()
						res_refresh = 0;						// must force a push of everything on next push tickle
						rm_sheep.Baa( 1, "pausing..." )

					case REQ_RESUME:
						msg.State = nil							// right now this cannot fail in ways we know about
						msg.Response_data = ""
						res_refresh = 0;						// must force a push of everything on next push tickle
						inv.pause_off()

					case REQ_SETQUEUES:							// driven about every second to reset the queues if a reservation state has changed
						now := time.Now().Unix()
						if now > last_qcheck  &&  inv.any_concluded( now - last_qcheck ) || inv.any_commencing( now - last_qcheck, 0 ) {
							rm_sheep.Baa( 1, "channel states: rm=%d rmlu=%d fq=%d net=%d agent=%d", len( rmgr_ch ), len( rmgrlu_ch ), len( fq_ch ), len( nw_ch ), len( am_ch ) )
							rm_sheep.Baa( 1, "reservation state change detected, requesting queue map from net-mgr" )
							tmsg := ipc.Mk_chmsg( )
							tmsg.Send_req( nw_ch, my_chan, queue_gen_type, time.Now().Unix(), nil )		// get a queue map; when it arrives we'll push to fqmgr and trigger flow-mod push
						}
						last_qcheck = now

					case REQ_PUSH:								// driven every few seconds to check for need to refresh because of switch max timeout setting
						if hto_limit > 0 {						// if reservation flow-mods are capped with a hard timeout limit
							now := time.Now().Unix()
							if now > res_refresh {
								rm_sheep.Baa( 2, "refreshing all reservations" )
								inv.reset_push()							// reset pushed flag on all reservations to cause active ones to be pushed again
								res_refresh = now + int64( rr_rate )		// push everything again in an hour

								inv.push_reservations( my_chan, alt_table, int64( hto_limit ), favour_v6 )			// force a push of all
							}
						}


					case REQ_PLEDGE_LIST:						// generate a list of pledges that are related to the given VM
						msg.Response_data, msg.State = inv.pledge_list(  msg.Req_data.( *string ) )

					case REQ_SETULCAP:							// user link capacity; expect array of two string pointers (name and value)
						data := msg.Req_data.( []*string )
						inv.add_ulcap( data[0], data[1] )
						retry_chkpt, last_chkpt = inv.write_chkpt( last_chkpt )

					// CAUTION: the requests below come back as asynch responses rather than as initial message
					case REQ_IE_RESERVE:						// an IE reservation failed
						msg.Response_ch = nil					// immediately disable to prevent loop
						inv.failed_push( msg )					// suss out the pledge and mark it unpushed

					case REQ_GEN_QMAP:							// response caries the queue map that now should be sent to fq-mgr to drive a queue update
						fallthrough

					case REQ_GEN_EPQMAP:
						rm_sheep.Baa( 1, "received queue map from network manager" )

						qlist := msg.Response_data.( []string )							// get the qulist map for our use first
						if send_meta_counter >= 200 {
							send_meta_fmods( qlist, alt_table )								// push meta rules
							send_meta_counter = 0
						} else {
							send_meta_counter++
						}

						msg.Response_ch = nil											// immediately disable to prevent loop
						fq_data := make( []interface{}, 1 )
						fq_data[FQ_QLIST] = msg.Response_data
						tmsg := ipc.Mk_chmsg( )
						tmsg.Send_req( fq_ch, nil, REQ_SETQUEUES, fq_data, nil )		// send the queue list to fq manager to deal with

						inv.push_reservations( my_chan, alt_table, int64( hto_limit ), favour_v6 )			// now safe to push reservations if any activated

					case REQ_VET_RETRY:
						if inv != nil && len( inv.retry ) > 0 {
							inv.vet_retries( )
						}

					case REQ_YANK_RES:										// yank a reservation from the inventory returning the pledge and allowing flow-mods to purge
						if msg.Response_ch != nil {
							msg.Response_data, msg.State = inv.yank_res( msg.Req_data.( *string ) )
						}

					/* deprecated -- moved to rm_lookup
					case REQ_GET_MIRRORS:									// user initiated get list of mirrors
						t := inv.Get_mirrorlist()
						msg.Response_data = &t;
					*/

					default:
						rm_sheep.Baa( 0, "WRN: res_mgr: unknown message: %d [TGURMG001]", msg.Msg_type )
						msg.Response_data = nil
						msg.State = fmt.Errorf( "res_mgr: unknown message (%d)", msg.Msg_type )
						msg.Response_ch = nil				// we don't respond to these.
				}	// end main channel case

		}		// end select

		rm_sheep.Baa( 3, "processing message complete: %d", msg.Msg_type )
		if msg.Response_ch != nil {			// if a response channel was provided
			msg.Response_ch <- msg			// send our result back to the requester
		}
	}
}
Ejemplo n.º 2
0
/*
	the main go routine to act on messages sent to our channel. We expect messages from the
	reservation manager, and from a tickler that causes us to evaluate the need to resize
	ovs queues.

	DSCP values:  Dscp values range from 0-64 decimal, but when described on or by
		flow-mods are shifted two bits to the left. The send flow mod function will
		do the needed shifting so all values outside of that one funciton should assume/use
		decimal values in the range of 0-64.

*/
func Fq_mgr(my_chan chan *ipc.Chmsg, sdn_host *string) {

	var (
		uri_prefix   string = ""
		msg          *ipc.Chmsg
		data         []interface{}      // generic list of data on some requests
		fdata        *Fq_req            // flow-mod request data
		qcheck_freq  int64              = 5
		hcheck_freq  int64              = 180
		host_list    *string                            // current set of openstack real hosts
		ip2mac       map[string]*string                 // translation from ip address to mac
		switch_hosts *string                            // from config file and overrides openstack list if given (mostly testing)
		ssq_cmd      *string                            // command string used to set switch queues (from config file)
		send_all     bool               = false         // send all flow-mods; false means send just ingress/egress and not intermediate switch f-mods
		alt_table    int                = DEF_ALT_TABLE // meta data marking table
		phost_suffix *string            = nil           // physical host suffix added to each host name in the list from openstack (config)

		//max_link_used	int64 = 0			// the current maximum link utilisation
	)

	fq_sheep = bleater.Mk_bleater(0, os.Stderr) // allocate our bleater and attach it to the master
	fq_sheep.Set_prefix("fq_mgr")
	tegu_sheep.Add_child(fq_sheep) // we become a child so that if the master vol is adjusted we'll react too

	// -------------- pick up config file data if there --------------------------------
	if *sdn_host == "" { // not supplied on command line, pull from config
		if sdn_host = cfg_data["default"]["sdn_host"]; sdn_host == nil { // no default; when not in config, then it's turned off and we send to agent
			sdn_host = &empty_str
		}
	}

	if cfg_data["default"]["queue_type"] != nil {
		if *cfg_data["default"]["queue_type"] == "endpoint" {
			send_all = false
		} else {
			send_all = true
		}
	}
	if p := cfg_data["default"]["alttable"]; p != nil { // this is the base; we use alt_table to alt_table + (n-1) when we need more than 1 table
		alt_table = clike.Atoi(*p)
	}

	if cfg_data["fqmgr"] != nil { // pick up things in our specific setion
		if dp := cfg_data["fqmgr"]["ssq_cmd"]; dp != nil { // set switch queue command
			ssq_cmd = dp
		}

		/*
			if p := cfg_data["fqmgr"]["default_dscp"]; p != nil {		// this is a single value and should not be confused with the dscp list in the default section of the config
				dscp = clike.Atoi( *p )
			}
		*/

		if p := cfg_data["fqmgr"]["queue_check"]; p != nil { // queue check frequency from the control file
			qcheck_freq = clike.Atoi64(*p)
			if qcheck_freq < 5 {
				qcheck_freq = 5
			}
		}

		if p := cfg_data["fqmgr"]["host_check"]; p != nil { // frequency of checking for new _real_ hosts from openstack
			hcheck_freq = clike.Atoi64(*p)
			if hcheck_freq < 30 {
				hcheck_freq = 30
			}
		}

		if p := cfg_data["fqmgr"]["switch_hosts"]; p != nil {
			switch_hosts = p
		}

		if p := cfg_data["fqmgr"]["verbose"]; p != nil {
			fq_sheep.Set_level(uint(clike.Atoi(*p)))
		}

		if p := cfg_data["fqmgr"]["phost_suffix"]; p != nil { // suffix added to physical host strings for agent commands
			if *p != "" {
				phost_suffix = p
				fq_sheep.Baa(1, "physical host names will be suffixed with: %s", *phost_suffix)
			}
		}
	}
	// ----- end config file munging ---------------------------------------------------

	//tklr.Add_spot( qcheck_freq, my_chan, REQ_SETQUEUES, nil, ipc.FOREVER );  	// tickle us every few seconds to adjust the ovs queues if needed

	if switch_hosts == nil {
		tklr.Add_spot(2, my_chan, REQ_CHOSTLIST, nil, 1)                     // tickle once, very soon after starting, to get a host list
		tklr.Add_spot(hcheck_freq, my_chan, REQ_CHOSTLIST, nil, ipc.FOREVER) // tickles us every once in a while to update host list
		fq_sheep.Baa(2, "host list will be requested from openstack every %ds", hcheck_freq)
	} else {
		host_list = switch_hosts
		fq_sheep.Baa(0, "static host list from config used for setting OVS queues: %s", *host_list)
	}

	if sdn_host != nil && *sdn_host != "" {
		uri_prefix = fmt.Sprintf("http://%s", *sdn_host)
	}

	fq_sheep.Baa(1, "flowmod-queue manager is running, sdn host: %s", *sdn_host)
	for {
		msg = <-my_chan // wait for next message
		msg.State = nil // default to all OK

		fq_sheep.Baa(3, "processing message: %d", msg.Msg_type)
		switch msg.Msg_type {
		case REQ_GEN_FMOD: // generic fmod; just pass it along w/o any special handling
			if msg.Req_data != nil {
				fdata = msg.Req_data.(*Fq_req) // pointer at struct with all of our expected goodies
				send_gfmod_agent(fdata, ip2mac, host_list, phost_suffix)
			}

		case REQ_BWOW_RESERVE: // oneway bandwidth flow-mod generation
			msg.Response_ch = nil          // nothing goes back from this
			fdata = msg.Req_data.(*Fq_req) // pointer at struct with all of the expected goodies
			send_bwow_fmods(fdata, ip2mac, phost_suffix)

		case REQ_BW_RESERVE: // bandwidth endpoint flow-mod creation; single agent script creates all needed fmods
			fdata = msg.Req_data.(*Fq_req) // pointer at struct with all of the expected goodies
			send_bw_fmods(fdata, ip2mac, phost_suffix)
			msg.Response_ch = nil // nothing goes back from this

		case REQ_IE_RESERVE: // proactive ingress/egress reservation flowmod  (this is likely deprecated as of 3/21/2015 -- resmgr invokes the bw_fmods script via agent)
			fdata = msg.Req_data.(*Fq_req) // user view of what the flow-mod should be

			if uri_prefix != "" { // an sdn controller -- skoogi -- is enabled
				msg.State = gizmos.SK_ie_flowmod(&uri_prefix, *fdata.Match.Ip1, *fdata.Match.Ip2, fdata.Expiry, fdata.Espq.Queuenum, fdata.Espq.Switch, fdata.Espq.Port)

				if msg.State == nil { // no error, no response to requestor
					fq_sheep.Baa(2, "proactive reserve successfully sent: uri=%s h1=%s h2=%s exp=%d qnum=%d swid=%s port=%d dscp=%d",
						uri_prefix, fdata.Match.Ip1, fdata.Match.Ip2, fdata.Expiry, fdata.Espq.Queuenum, fdata.Espq.Switch, fdata.Espq.Port)
					msg.Response_ch = nil
				} else {
					// do we need to suss out the id and mark it failed, or set a timer on it,  so as not to flood reqmgr with errors?
					fq_sheep.Baa(1, "ERR: proactive reserve failed: uri=%s h1=%s h2=%s exp=%d qnum=%d swid=%s port=%d  [TGUFQM008]",
						uri_prefix, fdata.Match.Ip1, fdata.Match.Ip2, fdata.Expiry, fdata.Espq.Queuenum, fdata.Espq.Switch, fdata.Espq.Port)
				}
			} else {
				// q-lite now generates one flowmod  in each direction because of the ITONS requirements
				if send_all || fdata.Espq.Queuenum > 1 { // if sending all fmods, or this has a non-intermediate queue
					cdata := fdata.Clone()       // copy so we can alter w/o affecting sender's copy
					if cdata.Espq.Port == -128 { // we'll assume in this case that the switch given is the host name and we need to set the switch to br-int
						swid := "br-int"
						cdata.Swid = &swid
					}

					if cdata.Resub == nil {
						resub_list := ""                         // resub to alternate table to set a meta mark, then to table 0 to hit openstack junk
						if cdata.Single_switch || fdata.Dir_in { // must use the base table for inbound traffic OR same switch traffic (bug 2015/1/26)
							resub_list = fmt.Sprintf("%d 0", alt_table) // base alt_table is for 'local' traffic (trafic that doesn't go through br-rl
						} else {
							resub_list = fmt.Sprintf("%d 0", alt_table+1) // base+1 is for OUTBOUND only traffic that must go through the rate limiting bridge
						}
						cdata.Resub = &resub_list
					}

					meta := "0x00/0x07" // match-value/mask; match only when meta neither of our two bits, nor the agent bit (0x04) are set
					cdata.Match.Meta = &meta

					if fdata.Dir_in { // inbound to this switch we need to revert dscp from our settings to the 'origianal' settings
						if cdata.Single_switch {
							cdata.Match.Dscp = -1 // there is no match if both on same switch
							send_gfmod_agent(cdata, ip2mac, host_list, phost_suffix)
						} else {
							cdata.Match.Dscp = cdata.Dscp // match the dscp that was added on ingress
							if !cdata.Dscp_koe {          // dropping the value on exit
								cdata.Action.Dscp = 0 // set action to turn it off, otherwise we let it ride (no overt action)
							}

							send_gfmod_agent(cdata, ip2mac, host_list, phost_suffix)
						}
					} else { // outbound from this switch set the dscp value specified on the reservation
						cdata.Match.Dscp = -1 // on outbound there is no dscp match, ensure this is off
						if cdata.Single_switch {
							send_gfmod_agent(cdata, ip2mac, host_list, phost_suffix) // in single switch mode there is no dscp value needed
						} else {
							cdata.Action.Dscp = cdata.Dscp // otherwise set the value and send
							send_gfmod_agent(cdata, ip2mac, host_list, phost_suffix)
						}
					}
				}

				msg.Response_ch = nil
			}

		case REQ_ST_RESERVE: // reservation fmods for traffic steering
			msg.Response_ch = nil // for now, nothing goes back
			if msg.Req_data != nil {
				fq_data := msg.Req_data.(*Fq_req) // request data
				if uri_prefix != "" {             // an sdn controller -- skoogi -- is enabled (not supported)
					fq_sheep.Baa(0, "ERR: steering reservations are not supported with skoogi (SDNC); no flow-mods pushed")
				} else {
					send_stfmod_agent(fq_data, ip2mac, host_list)
				}
			} else {
				fq_sheep.Baa(0, "CRI: missing data on st-reserve request to fq-mgr")
			}

		case REQ_SK_RESERVE: // send a reservation to skoogi
			data = msg.Req_data.([]interface{}) // msg data expected to be array of interface: h1, h2, expiry, queue h1/2 must be IP addresses
			if uri_prefix != "" {
				fq_sheep.Baa(2, "msg to reserve: %s %s %s %d %d", uri_prefix, data[0].(string), data[1].(string), data[2].(int64), data[3].(int))
				msg.State = gizmos.SK_reserve(&uri_prefix, data[0].(string), data[1].(string), data[2].(int64), data[3].(int))
			} else {
				fq_sheep.Baa(1, "reservation not sent, no sdn-host defined:  %s %s %s %d %d", uri_prefix, data[0].(string), data[1].(string), data[2].(int64), data[3].(int))
			}

		case REQ_SETQUEUES: // request from reservation manager which indicates something changed and queues need to be reset
			qlist := msg.Req_data.([]interface{})[0].([]string)
			if ssq_cmd != nil {
				adjust_queues(qlist, ssq_cmd, host_list) // if writing to a file and driving a local script
			} else {
				adjust_queues_agent(qlist, host_list, phost_suffix) // if sending json to an agent
			}

		case REQ_CHOSTLIST: // this is tricky as it comes from tickler as a request, and from osifmgr as a response, be careful!
			msg.Response_ch = nil // regardless of source, we should not reply to this request

			if msg.State != nil || msg.Response_data != nil { // response from ostack if with list or error
				if msg.Response_data.(*string) != nil {
					hls := strings.TrimLeft(*(msg.Response_data.(*string)), " \t") // ditch leading whitespace
					hl := &hls
					if *hl != "" {
						host_list = hl // ok to use it
						if phost_suffix != nil {
							fq_sheep.Baa(2, "host list from osif before suffix added: %s", *host_list)
							host_list = add_phost_suffix(host_list, phost_suffix) // in some cases ostack sends foo, but we really need to use foo-suffix (sigh)
						}
						send_hlist_agent(host_list) // send to agent_manager
						fq_sheep.Baa(2, "host list received from osif: %s", *host_list)
					} else {
						fq_sheep.Baa(1, "host list received from osif was discarded: ()")
					}
				} else {
					fq_sheep.Baa(0, "WRN: no  data from openstack; expected host list string  [TGUFQM009]")
				}
			} else {
				req_hosts(my_chan, fq_sheep) // send requests to osif for data
			}

		case REQ_IP2MACMAP: // a new map from osif
			if msg.Req_data != nil {
				newmap := msg.Req_data.(map[string]*string)
				if len(newmap) > 0 {
					ip2mac = newmap // safe to replace
					fq_sheep.Baa(2, "ip2mac translation received from osif: %d elements", len(ip2mac))
				} else {
					if ip2mac != nil {
						fq_sheep.Baa(2, "ip2mac translation received from osif: 0 elements -- kept old table with %d elements", len(ip2mac))
					} else {
						fq_sheep.Baa(2, "ip2mac translation received from osif: 0 elements -- no existing table to keep")
					}
				}
			} else {
				fq_sheep.Baa(0, "WRN: no  data from osif (nil map); expected ip2mac translation map  [TGUFQM010]")
			}
			msg.State = nil // state is always good

		default:
			fq_sheep.Baa(1, "unknown request: %d", msg.Msg_type)
			msg.Response_data = nil
			if msg.Response_ch != nil {
				msg.State = fmt.Errorf("unknown request (%d)", msg.Msg_type)
			}
		}

		fq_sheep.Baa(3, "processing message complete: %d", msg.Msg_type)
		if msg.Response_ch != nil { // if a reqponse channel was provided
			fq_sheep.Baa(3, "sending response: %d", msg.Msg_type)
			msg.Response_ch <- msg // send our result back to the requestor
		}
	}
}