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watcher.go
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watcher.go
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// Copyright (C) 2015 John Howard Palevich. All Rights Reserved.
package watcher
import (
"log"
"net"
"time"
"github.com/jackpal/SeattleSnowman/db"
"github.com/jackpal/SeattleSnowman/router"
)
// Internal implementation of the Watcher.
type firewallUpdater struct {
db db.DB
calendar db.Calendar
firewall router.Firewall
addressGroup string
goodUntil time.Time
}
func (f *firewallUpdater) getBlockList() (blocked []db.DeviceIP, goodUntil time.Time, err error) {
return db.GetBlockList(f.db, f.calendar, time.Now())
}
func (f *firewallUpdater) updateFirewall() (newWakeTime bool, err error) {
blocked, goodUntil, err := f.getBlockList()
log.Printf("updateFirewall(%v) goodUntil %s",
blocked, goodUntil.Format(time.Kitchen))
if err != nil {
return
}
newWakeTime = !f.goodUntil.Equal(goodUntil)
f.goodUntil = goodUntil
var ips router.IPs
for _, deviceIP := range blocked {
ips = append(ips, net.IP(deviceIP))
}
log.Printf("new blocklist: %v", ips)
err = f.firewall.SetAddressGroup(f.addressGroup, ips)
return
}
type Watcher struct {
db db.DB
wi *firewallUpdater
commands chan func(*firewallUpdater)
timeout chan bool
}
func NewWatcher(db db.DB, calendar db.Calendar, firewall router.Firewall,
addressGroup string) (w *Watcher) {
return &Watcher{
db,
&firewallUpdater{db, calendar, firewall, addressGroup, time.Time{}},
make(chan func(*firewallUpdater), 1),
make(chan bool, 1),
}
}
func (w *Watcher) pingFirewall() {
w.commands <- func(wi *firewallUpdater) {
oldWakeTime := wi.goodUntil
_, err := wi.updateFirewall()
if err != nil {
log.Printf("Error updating firewall: %v", err)
}
w.maybeScheduleTimeout(oldWakeTime, w.wi.goodUntil)
}
}
func (w *Watcher) pingIfNoError(errIn error) (err error) {
err = errIn
if err == nil {
w.pingFirewall()
}
return
}
func (w *Watcher) AddDevices(devices []db.Device) (err error) {
err = w.pingIfNoError(w.db.AddAll(devices))
return
}
func (w *Watcher) AddDevice(device db.Device) (err error) {
err = w.pingIfNoError(w.db.Add(device))
return
}
func (w *Watcher) ModifyActiveUntil(ip db.DeviceIP, delta time.Duration) (err error) {
err = w.pingIfNoError(w.db.ModifyActiveUntil(ip, delta, time.Now()))
return
}
func (w *Watcher) SetActiveUntil(ip db.DeviceIP, activeUntil time.Time) (err error) {
err = w.pingIfNoError(w.db.SetActiveUntil(ip, activeUntil))
return
}
func (w *Watcher) maybeScheduleTimeout(oldWakeTime time.Time, wakeTime time.Time) {
if !wakeTime.IsZero() &&
(oldWakeTime.IsZero() || wakeTime.Before(oldWakeTime)) {
sleepTime := wakeTime.Sub(time.Now())
go func() {
time.Sleep(sleepTime)
w.timeout <- true
}()
}
}
func (w *Watcher) Close() (err error) {
close(w.commands)
return
}
func (w *Watcher) State() (state []db.Device, err error) {
state, err = w.db.All()
if err != nil {
return
}
// To simplify UI, treat all times before now as zero.
state = zeroTimesBefore(state, time.Now())
return
}
func zeroTimesBefore(state []db.Device, t time.Time) (stateZ []db.Device) {
for _, d := range state {
activeUntil := d.ActiveUntil
if !activeUntil.IsZero() && activeUntil.Before(t) {
d.ActiveUntil = time.Time{}
}
stateZ = append(stateZ, d)
}
return
}
func (w *Watcher) BlockList() (blockList []db.DeviceIP, goodUntil time.Time, err error) {
return w.wi.getBlockList()
}
func (w *Watcher) Start() (err error) {
go w.loop()
return
}
func (w *Watcher) loop() {
w.updateFirewall()
for {
select {
case command := <-w.commands:
command(w.wi)
case <-w.timeout:
w.updateFirewall()
}
}
}
func (w *Watcher) updateFirewall() {
oldWakeTime := w.wi.goodUntil
w.wi.updateFirewall()
w.maybeScheduleTimeout(oldWakeTime, w.wi.goodUntil)
}