138 lines
3.3 KiB
Go
138 lines
3.3 KiB
Go
// Copyright 2017 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package sync
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import (
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"fmt"
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"log"
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"net"
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"time"
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"git.narnian.us/lordwelch/externalip"
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"golang.org/x/time/rate"
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)
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type IPType uint
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const (
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IP4 IPType = 4
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IP6 IPType = 6
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)
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// IPAddressPoller is a poller used to check the value
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// of the current public internet IP address.
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type IPAddressPoller struct {
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channels []chan string
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pollInterval time.Duration
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consensus *externalip.Consensus
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iptype IPType
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limiter *rate.Limiter
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ip net.IP
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}
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func NewIPAddressPoller(iptype IPType, pollInterval time.Duration, consensus *externalip.Consensus) *IPAddressPoller {
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if consensus == nil {
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return &IPAddressPoller{
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pollInterval: pollInterval,
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consensus: externalip.DefaultConsensus(nil, nil),
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iptype: iptype,
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limiter: rate.NewLimiter(rate.Every(5*time.Second), 1),
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}
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}
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return &IPAddressPoller{
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pollInterval: pollInterval,
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consensus: consensus,
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iptype: iptype,
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limiter: rate.NewLimiter(rate.Every(5*time.Second), 1),
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}
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}
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// Channel returns a channel that receives data whenever an
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// IP address value is received.
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func (i *IPAddressPoller) Channel() <-chan string {
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c := make(chan string, 1)
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i.channels = append(i.channels, c)
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return c
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}
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// poll() runs a single polling event and retrieving the internet IP.
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func (i *IPAddressPoller) poll() error {
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var (
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err error
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ip net.IP
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)
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if i.limiter.Allow() {
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ip, err = i.consensus.ExternalIP(uint(i.iptype))
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if err != nil {
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return fmt.Errorf("could not obtain IP address: %w", err)
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}
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if ip.To4() != nil && i.iptype == 6 {
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return nil
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}
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if ip.To4() == nil && i.iptype == 4 {
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return nil
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}
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log.Printf("Found IP %v %v", ip, len(ip))
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i.ip = ip
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} else {
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ip = i.ip
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log.Printf("Using cached IP %v %v", ip, len(ip))
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}
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for _, c := range i.channels {
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select {
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case c <- ip.String():
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default:
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}
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}
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return nil
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}
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// request() makes a request to a URL to get the internet IP address.
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// func html_parser(url string) (string, error) {
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// z := html.NewTokenizer(resp.Body)
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// for {
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// tt := z.Next()
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// switch tt {
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// case html.ErrorToken:
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// return "", z.Err()
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// case html.TextToken:
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// text := strings.Trim(string(z.Text()), " \n\t")
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// if text != "" {
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// ip := ""
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// fmt.Sscanf(text, "Current IP Address: %s", &ip)
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// if ip != "" {
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// return strings.Trim(ip, " \n\t"), nil
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// }
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// }
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// }
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// }
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// }
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// Run starts the main loop for the poller.
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func (i *IPAddressPoller) Run(stopCh <-chan struct{}) error {
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if err := i.poll(); err != nil {
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log.Printf("Error polling for IP: %v", err)
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}
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for {
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select {
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case <-time.After(i.pollInterval):
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if err := i.poll(); err != nil {
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log.Printf("Error polling for IP: %v", err)
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}
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case <-stopCh:
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return nil
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}
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}
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}
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