111 lines
2.7 KiB
Go
111 lines
2.7 KiB
Go
package ssdp
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import (
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"bytes"
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"fmt"
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"net"
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"github.com/koron/go-ssdp/internal/multicast"
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)
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// AnnounceAlive sends ssdp:alive message.
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// location should be a string or a ssdp.LocationProvider.
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func AnnounceAlive(nt, usn string, location interface{}, server string, maxAge int, localAddr string) error {
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locProv, err := toLocationProvider(location)
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if err != nil {
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return err
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}
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// dial multicast UDP packet.
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conn, err := multicast.Listen(&multicast.AddrResolver{Addr: localAddr})
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if err != nil {
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return err
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}
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defer conn.Close()
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// build and send message.
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addr, err := multicast.SendAddr()
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if err != nil {
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return err
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}
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msg := &aliveDataProvider{
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host: addr,
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nt: nt,
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usn: usn,
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location: locProv,
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server: server,
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maxAge: maxAge,
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}
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if _, err := conn.WriteTo(msg, addr); err != nil {
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return err
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}
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return nil
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}
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type aliveDataProvider struct {
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host net.Addr
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nt string
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usn string
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location LocationProvider
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server string
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maxAge int
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}
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func (p *aliveDataProvider) Bytes(ifi *net.Interface) []byte {
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return buildAlive(p.host, p.nt, p.usn, p.location.Location(nil, ifi), p.server, p.maxAge)
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}
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var _ multicast.DataProvider = (*aliveDataProvider)(nil)
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func buildAlive(raddr net.Addr, nt, usn, location, server string, maxAge int) []byte {
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// bytes.Buffer#Write() is never fail, so we can omit error checks.
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b := new(bytes.Buffer)
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b.WriteString("NOTIFY * HTTP/1.1\r\n")
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fmt.Fprintf(b, "HOST: %s\r\n", raddr.String())
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fmt.Fprintf(b, "NT: %s\r\n", nt)
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fmt.Fprintf(b, "NTS: %s\r\n", "ssdp:alive")
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fmt.Fprintf(b, "USN: %s\r\n", usn)
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if location != "" {
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fmt.Fprintf(b, "LOCATION: %s\r\n", location)
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}
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if server != "" {
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fmt.Fprintf(b, "SERVER: %s\r\n", server)
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}
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fmt.Fprintf(b, "CACHE-CONTROL: max-age=%d\r\n", maxAge)
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b.WriteString("\r\n")
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return b.Bytes()
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}
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// AnnounceBye sends ssdp:byebye message.
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func AnnounceBye(nt, usn, localAddr string) error {
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// dial multicast UDP packet.
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conn, err := multicast.Listen(&multicast.AddrResolver{Addr: localAddr})
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if err != nil {
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return err
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}
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defer conn.Close()
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// build and send message.
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addr, err := multicast.SendAddr()
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if err != nil {
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return err
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}
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msg, err := buildBye(addr, nt, usn)
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if err != nil {
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return err
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}
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if _, err := conn.WriteTo(multicast.BytesDataProvider(msg), addr); err != nil {
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return err
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}
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return nil
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}
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func buildBye(raddr net.Addr, nt, usn string) ([]byte, error) {
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b := new(bytes.Buffer)
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// FIXME: error should be checked.
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b.WriteString("NOTIFY * HTTP/1.1\r\n")
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fmt.Fprintf(b, "HOST: %s\r\n", raddr.String())
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fmt.Fprintf(b, "NT: %s\r\n", nt)
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fmt.Fprintf(b, "NTS: %s\r\n", "ssdp:byebye")
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fmt.Fprintf(b, "USN: %s\r\n", usn)
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b.WriteString("\r\n")
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return b.Bytes(), nil
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}
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