174 lines
3.2 KiB
Go
174 lines
3.2 KiB
Go
package ssdp
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"net"
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"net/http"
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"sync"
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)
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// Monitor monitors SSDP's alive and byebye messages.
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type Monitor struct {
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alive AliveHandler
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bye ByeHandler
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conn net.PacketConn
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wg sync.WaitGroup
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}
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// NewMonitor creates a new Monitor.
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func NewMonitor(alive AliveHandler, bye ByeHandler) (*Monitor, error) {
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if alive == nil {
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alive = nullAlive
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}
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if bye == nil {
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bye = nullBye
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}
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conn, err := multicastListen("0.0.0.0:1900")
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if err != nil {
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return nil, err
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}
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logf("monitoring on %s", conn.LocalAddr().String())
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m := &Monitor{
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alive: alive,
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bye: bye,
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conn: conn,
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}
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m.wg.Add(1)
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go func() {
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m.serve()
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m.wg.Done()
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}()
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return m, nil
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}
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func (m *Monitor) serve() error {
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buf := make([]byte, 65535)
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for {
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n, addr, err := m.conn.ReadFrom(buf)
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if err != nil {
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if err == io.EOF {
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return nil
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}
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return err
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}
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msg := make([]byte, n)
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copy(msg, buf[:n])
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go m.handleRaw(addr, msg)
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}
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}
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func (m *Monitor) handleRaw(addr net.Addr, raw []byte) error {
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req, err := http.ReadRequest(bufio.NewReader(bytes.NewReader(raw)))
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if err != nil {
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return err
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}
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switch nts := req.Header.Get("NTS"); nts {
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case "ssdp:alive":
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if req.Method != "NOTIFY" {
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return fmt.Errorf("unexpected method for %q: %s", "ssdp:alive", req.Method)
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}
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m.alive(&Alive{
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From: addr,
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Type: req.Header.Get("NT"),
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USN: req.Header.Get("USN"),
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Location: req.Header.Get("LOCATION"),
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Server: req.Header.Get("SERVER"),
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rawHeader: req.Header,
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})
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case "ssdp:byebye":
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if req.Method != "NOTIFY" {
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return fmt.Errorf("unexpected method for %q: %s", "ssdp:byebye", req.Method)
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}
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m.bye(&Bye{
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From: addr,
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Type: req.Header.Get("NT"),
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USN: req.Header.Get("USN"),
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rawHeader: req.Header,
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})
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default:
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return fmt.Errorf("unknown NTS: %s", nts)
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}
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return nil
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}
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// Close closes monitoring.
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func (m *Monitor) Close() error {
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if m.conn != nil {
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m.conn.Close()
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m.conn = nil
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m.wg.Wait()
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}
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return nil
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}
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// Alive represents SSDP's ssdp:alive message.
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type Alive struct {
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// From is a sender of this message
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From net.Addr
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// Type is a property of "NT"
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Type string
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// USN is a property of "USN"
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USN string
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// Location is a property of "LOCATION"
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Location string
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// Server is a property of "SERVER"
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Server string
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rawHeader http.Header
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maxAge *int
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}
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// Header returns all properties in response of search.
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func (m *Alive) Header() http.Header {
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return m.rawHeader
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}
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// MaxAge extracts "max-age" value from "CACHE-CONTROL" property.
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func (m *Alive) MaxAge() int {
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if m.maxAge == nil {
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m.maxAge = new(int)
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*m.maxAge = extractMaxAge(m.rawHeader.Get("CACHE-CONTROL"), -1)
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}
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return *m.maxAge
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}
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// AliveHandler is handler of Alive message.
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type AliveHandler func(*Alive)
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func nullAlive(*Alive) {
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// nothing to do.
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}
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// Bye represents SSDP's ssdp:byebye message.
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type Bye struct {
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// From is a sender of this message
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From net.Addr
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// Type is a property of "NT"
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Type string
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// USN is a property of "USN"
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USN string
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rawHeader http.Header
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}
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// Header returns all properties in response of search.
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func (m *Bye) Header() http.Header {
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return m.rawHeader
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}
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// ByeHandler is handler of Bye message.
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type ByeHandler func(*Bye)
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func nullBye(*Bye) {
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// nothing to do.
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}
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