package ifplugo
// This file is part of ifplugo.
//
// ifplugo is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// ifplugo is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with ifplugo; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
/*
#cgo LDFLAGS: -ldaemon
#include <interface.h>
*/
import (
"C"
)
import (
"syscall"
"time"
)
// InterfaceStatus represents the link status of an interface.
type InterfaceStatus int
const (
// InterfaceUnknown represents an interface with no assigned state.
InterfaceUnknown InterfaceStatus = iota
// InterfaceUp represents an interface with a cable connected.
InterfaceUp
// InterfaceDown represents an interface with no cable connected.
InterfaceDown
// InterfaceErr represents an interface with errors querying its status.
InterfaceErr
)
var statusLookup = map[C.interface_status_t]InterfaceStatus{
C.IFSTATUS_UP: InterfaceUp,
C.IFSTATUS_DOWN: InterfaceDown,
C.IFSTATUS_ERR: InterfaceErr,
}
func (s InterfaceStatus) String() string {
switch s {
case InterfaceUp:
return "link"
case InterfaceDown:
return "no link"
case InterfaceErr:
return "error"
default:
return "unknown"
}
}
// GetLinkStatus returns, for a given interface, the corresponding status code
// at the time of the call. If any error was encountered (e.g. invalid
// interface, etc.) we simply return ifplugo.InterfaceErr.
func GetLinkStatus(iface string) (InterfaceStatus, error) {
fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM,
syscall.IPPROTO_IP)
if err != nil {
return InterfaceErr, err
}
defer syscall.Close(fd)
e := C.interface_detect_beat_ethtool(C.int(fd), C.CString(iface))
if e == C.IFSTATUS_ERR {
e = C.interface_detect_beat_mii(C.int(fd), C.CString(iface))
if e == C.IFSTATUS_ERR {
e = C.interface_detect_beat_wlan(C.int(fd), C.CString(iface))
if e == C.IFSTATUS_ERR {
e = C.interface_detect_beat_iff(C.int(fd), C.CString(iface))
}
}
}
return statusLookup[e], nil
}
// LinkStatusMonitor represents a concurrent software component that
// periodically checks a list of given interfaces and returns their link status
// via a specified channel.
type LinkStatusMonitor struct {
PollPeriod time.Duration
LastStatus map[string]InterfaceStatus
OutChan chan LinkStatusSample
CloseChan chan bool
ClosedChan chan bool
Ifaces []string
}
// LinkStatusSample is a single description of the link status at a given time.
// Changed is set to true if the state is different than the previously emitted
// one.
type LinkStatusSample struct {
Ifaces map[string]InterfaceStatus
}
// MakeLinkStatusMonitor creates a new LinkStatusMonitor, polling each interval
// given in pollPeriod for the status information of the interfaces given in
// ifaces and outputting results as a map of interface->status pairs in the
// channel outChan.
func MakeLinkStatusMonitor(pollPeriod time.Duration, ifaces []string,
outChan chan LinkStatusSample) *LinkStatusMonitor {
a := &LinkStatusMonitor{
PollPeriod: pollPeriod,
OutChan: outChan,
CloseChan: make(chan bool),
ClosedChan: make(chan bool),
Ifaces: ifaces,
LastStatus: make(map[string]InterfaceStatus),
}
return a
}
func (a *LinkStatusMonitor) flush() error {
out := LinkStatusSample{
Ifaces: make(map[string]InterfaceStatus),
}
changed := false
for _, iface := range a.Ifaces {
v, err := GetLinkStatus(iface)
if err != nil {
out.Ifaces[iface] = InterfaceUnknown
}
out.Ifaces[iface] = v
if a.LastStatus[iface] != out.Ifaces[iface] {
changed = true
a.LastStatus[iface] = out.Ifaces[iface]
}
}
if changed {
a.OutChan <- out
}
return nil
}
// Run starts watching interfaces in the background.
func (a *LinkStatusMonitor) Run() {
go func() {
i := 0 * time.Second
for {
select {
case <-a.CloseChan:
close(a.ClosedChan)
return
default:
if i >= a.PollPeriod {
a.flush()
i = 0 * time.Second
}
time.Sleep(1 * time.Second)
i += 1 * time.Second
}
}
}()
}
// Stop causes the monitor to cease monitoring interfaces.
func (a *LinkStatusMonitor) Stop() {
close(a.CloseChan)
<-a.ClosedChan
}