Added device disovery (based on mDNS)

client.go

@@ -14,7 +14,7 @@ import (
 
 const (
 	DefaultTimeout    = 10 * time.Second
-	DefaultPort       = "6053"
+	DefaultPort       = 6053
 	defaultClientInfo = "maze.io go/esphome"
 )
 

cmd/client.go

@@ -5,7 +5,7 @@ import (
 	"net"
 	"os"
 
-	"maze.io/esphome"
+	"maze.io/x/esphome"
 )
 
 const (

cmd/esphome-discover/main.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"log"
+
+	"maze.io/x/esphome"
+)
+
+func main() {
+	devices := make(chan *esphome.Device, 32)
+	go dump(devices)
+
+	if err := esphome.Discover(devices); err != nil {
+		log.Fatalln("discovery failed:", err)
+	}
+}
+
+func dump(devices <-chan *esphome.Device) {
+	for device := range devices {
+		log.Printf("discovered %s on %s (version %s)",
+			device.Name, device.Addr(), device.Version)
+	}
+}

discover.go

@@ -0,0 +1,365 @@
+package esphome
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"strconv"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/miekg/dns"
+)
+
+const (
+	DefaultMDNSService = "_esphomelib._tcp"
+	DefaultMDNSDomain  = "local"
+	DefaultMDNSTimeout = 5 * time.Second
+
+	mDNSIP4               = "224.0.0.251"
+	mDNSIP6               = "ff02::fb"
+	mDNSPort              = 5353
+	forceUnicastResponses = false
+)
+
+var (
+	mDNSAddr4 = &net.UDPAddr{IP: net.ParseIP(mDNSIP4), Port: mDNSPort}
+	mDNSAddr6 = &net.UDPAddr{IP: net.ParseIP(mDNSIP6), Port: mDNSPort}
+)
+
+type Device struct {
+	Name    string
+	Host    string
+	Port    int
+	IP      net.IP
+	IP6     net.IP
+	Version string
+
+	sent bool
+}
+
+// Addr returns the device API address.
+func (d *Device) Addr() string {
+	if d.IP6 != nil {
+		return (&net.TCPAddr{IP: d.IP6, Port: d.Port}).String()
+	} else if d.IP != nil {
+		return (&net.TCPAddr{IP: d.IP, Port: d.Port}).String()
+	}
+	return net.JoinHostPort(d.Host, strconv.Itoa(d.Port))
+}
+
+func (d *Device) complete() bool {
+	return d.Host != "" && (d.IP != nil || d.IP6 != nil)
+}
+
+func Discover(devices chan<- *Device) error {
+	return DiscoverService(devices, DefaultMDNSService, DefaultMDNSDomain, DefaultMDNSTimeout)
+}
+
+func DiscoverService(devices chan<- *Device, service, domain string, timeout time.Duration) error {
+	c, err := newmDNSClient()
+	if err != nil {
+		return err
+	}
+	defer c.Close()
+
+	return c.query(devices, service, domain, timeout)
+}
+
+type mDNSClient struct {
+	// Unicast
+	uc4, uc6 *net.UDPConn
+
+	// Multicast
+	mc4, mc6 *net.UDPConn
+
+	closed   int32
+	closedCh chan struct{}
+}
+
+func newmDNSClient() (*mDNSClient, error) {
+	uc4, _ := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0})
+	uc6, _ := net.ListenUDP("udp6", &net.UDPAddr{IP: net.IPv6zero, Port: 0})
+	if uc4 == nil && uc6 == nil {
+		return nil, errors.New("esphome: failed to bind to any unicast UDP port")
+	}
+
+	mc4, _ := net.ListenMulticastUDP("udp4", nil, mDNSAddr4)
+	mc6, _ := net.ListenMulticastUDP("udp6", nil, mDNSAddr6)
+	if uc4 == nil && uc6 == nil {
+		if uc4 != nil {
+			_ = uc4.Close()
+		}
+		if uc6 != nil {
+			_ = uc6.Close()
+		}
+		return nil, errors.New("esphome: failed to bind to any multicast TCP port")
+	}
+
+	return &mDNSClient{
+		uc4:      uc4,
+		uc6:      uc6,
+		mc4:      mc4,
+		mc6:      mc6,
+		closedCh: make(chan struct{}),
+	}, nil
+}
+
+func (c *mDNSClient) Close() error {
+	if !atomic.CompareAndSwapInt32(&c.closed, 0, 1) {
+		// something else already closed it
+		return nil
+	}
+	close(c.closedCh)
+	if c.uc4 != nil {
+		_ = c.uc4.Close()
+	}
+	if c.uc6 != nil {
+		_ = c.uc6.Close()
+	}
+	if c.mc4 != nil {
+		_ = c.mc4.Close()
+	}
+	if c.mc6 != nil {
+		_ = c.mc6.Close()
+	}
+
+	return nil
+}
+
+/*
+query performs mDNS service discovery:
+
+  client:  question _esphomelib._tcp.local. IN PTR?
+  servers: response _esphomelib._tcp.local. IN PTR  <hostname>._esphomelib._tcp.local
+         <hostname>._esphomelib._tcp.local. IN SRV  <hostname>.local. <port> 0 0
+         <hostname>._esphomelib._tcp.local. IN TXT  <record>*
+                          <hostname>.local. IN A    <ipv4 address>
+                          <hostname>.local. IN AAAA <ipv6 address>
+*/
+func (c *mDNSClient) query(devices chan<- *Device, service, domain string, timeout time.Duration) error {
+	// Create the service name
+	addr := fmt.Sprintf("%s.%s", strings.Trim(service, "."), strings.Trim(domain, "."))
+
+	// Start listening for response packets
+	var (
+		ctx, cancel = context.WithTimeout(context.Background(), timeout)
+		msgs        = make(chan *dns.Msg, 32)
+	)
+	defer cancel()
+	go c.recv(ctx, c.uc4, msgs)
+	go c.recv(ctx, c.uc6, msgs)
+	go c.recv(ctx, c.mc4, msgs)
+	go c.recv(ctx, c.mc6, msgs)
+
+	q := new(dns.Msg)
+	q.SetQuestion(addr+".", dns.TypePTR)
+	// RFC 6762, section 18.12.  Repurposing of Top Bit of qclass in Question
+	// Section
+	//
+	// In the Question Section of a Multicast DNS query, the top bit of the qclass
+	// field is used to indicate that unicast responses are preferred for this
+	// particular question.  (See Section 5.4.)
+	q.Question[0].Qclass |= 1 << 15
+	q.RecursionDesired = false
+	if err := c.send(q); err != nil {
+		return err
+	}
+
+	var partial = make(map[string]*Device)
+	for ctx.Err() == nil {
+		select {
+		case replies := <-msgs:
+			var d *Device
+			for _, a := range append(replies.Answer, replies.Extra...) {
+				switch rr := a.(type) {
+				case *dns.PTR:
+					d = c.parsePTR(addr, partial, rr)
+				case *dns.SRV:
+					d = c.parseSRV(addr, partial, rr)
+				case *dns.A:
+					d = c.parseA(domain, partial, rr)
+				case *dns.AAAA:
+					d = c.parseAAAA(domain, partial, rr)
+				case *dns.TXT:
+					d = c.parseTXT(addr, partial, rr)
+				}
+			}
+
+			if d == nil {
+				continue
+			}
+
+			if d.complete() {
+				//log.Printf("complete device: %#+v", d)
+				if !d.sent {
+					select {
+					case devices <- d:
+					default:
+					}
+					d.sent = true
+				}
+			}
+
+		case <-ctx.Done():
+			return nil
+		}
+	}
+
+	return ctx.Err()
+}
+
+func (c *mDNSClient) parsePTR(addr string, partial map[string]*Device, rr *dns.PTR) *Device {
+	// _esphomelib._tcp.local. IN PTR  <hostname>._esphomelib._tcp.local
+	index := strings.IndexByte(rr.Ptr, '.')
+	if index == -1 {
+		return nil
+	}
+
+	hostname := rr.Ptr[:index]
+	if !strings.EqualFold(strings.Trim(rr.Hdr.Name, "."), addr) {
+		return nil
+	}
+
+	return ensureDevice(partial, hostname)
+}
+
+func (c *mDNSClient) parseSRV(addr string, partial map[string]*Device, rr *dns.SRV) *Device {
+	// <hostname>._esphomelib._tcp.local. IN SRV  <hostname>.local. <port> 0 0
+	index := strings.IndexByte(rr.Hdr.Name, '.')
+	if index == -1 {
+		return nil
+	}
+
+	hostname, suffix := rr.Hdr.Name[:index], strings.Trim(rr.Hdr.Name[index+1:], ".")
+	if !strings.EqualFold(suffix, addr) {
+		log.Printf("%q != %q", suffix, addr)
+		return nil
+	}
+
+	d := ensureDevice(partial, hostname)
+	d.Host = rr.Target
+	d.Port = int(rr.Port)
+	return d
+}
+
+func (c *mDNSClient) parseTXT(addr string, partial map[string]*Device, rr *dns.TXT) *Device {
+	// <hostname>._esphomelib._tcp.local. IN TXT  <record>*
+	index := strings.IndexByte(rr.Hdr.Name, '.')
+	if index == -1 {
+		return nil
+	}
+
+	hostname, suffix := rr.Hdr.Name[:index], strings.Trim(rr.Hdr.Name[index+1:], ".")
+	if !strings.EqualFold(suffix, addr) {
+		log.Printf("%q != %q", suffix, addr)
+		return nil
+
+	}
+
+	d := ensureDevice(partial, hostname)
+	for _, t := range rr.Txt {
+		if i := strings.IndexByte(t, '='); i > -1 {
+			switch t[:i] {
+			case "address":
+				d.Host = t[i+1:]
+			case "version":
+				d.Version = t[i+1:]
+			}
+		}
+	}
+	return d
+}
+
+func (c *mDNSClient) parseA(domain string, partial map[string]*Device, rr *dns.A) *Device {
+	// <hostname>.local. IN A    <ipv4 address>
+	index := strings.IndexByte(rr.Hdr.Name, '.')
+	if index == -1 {
+		return nil
+	}
+
+	hostname, suffix := rr.Hdr.Name[:index], strings.Trim(rr.Hdr.Name[index+1:], ".")
+	if !strings.EqualFold(suffix, domain) {
+		log.Printf("%q != %q", suffix, domain)
+		return nil
+	}
+
+	d := ensureDevice(partial, hostname)
+	d.IP = rr.A
+	return d
+}
+
+func (c *mDNSClient) parseAAAA(domain string, partial map[string]*Device, rr *dns.AAAA) *Device {
+	// <hostname>.local. IN AAAA <ipv6 address>
+	index := strings.IndexByte(rr.Hdr.Name, '.')
+	if index == -1 {
+		return nil
+	}
+
+	hostname, suffix := rr.Hdr.Name[:index], strings.Trim(rr.Hdr.Name[index+1:], ".")
+	if !strings.EqualFold(suffix, domain) {
+		log.Printf("%q != %q", suffix, domain)
+		return nil
+	}
+
+	d := ensureDevice(partial, hostname)
+	d.IP6 = rr.AAAA
+	return d
+}
+
+func ensureDevice(partial map[string]*Device, name string) *Device {
+	name = strings.Trim(name, ".")
+	if d, ok := partial[name]; ok {
+		return d
+	}
+
+	d := &Device{Name: name, Port: DefaultPort}
+	partial[name] = d
+	return d
+}
+
+func ensureDeviceAlias(partial map[string]*Device, src, dst string) {
+	partial[dst] = ensureDevice(partial, src)
+}
+
+func (c *mDNSClient) recv(ctx context.Context, l *net.UDPConn, msgCh chan *dns.Msg) {
+	if l == nil {
+		return
+	}
+
+	buf := make([]byte, 65536)
+	for ctx.Err() == nil {
+		n, err := l.Read(buf)
+		if err != nil {
+			continue
+		}
+		msg := new(dns.Msg)
+		if err := msg.Unpack(buf[:n]); err != nil {
+			continue
+		}
+		select {
+		case msgCh <- msg:
+		case <-ctx.Done():
+			return
+		}
+	}
+}
+
+func (c *mDNSClient) send(q *dns.Msg) error {
+	buf, err := q.Pack()
+	if err != nil {
+		return err
+	}
+
+	if c.uc4 != nil {
+		c.uc4.WriteToUDP(buf, mDNSAddr4)
+	}
+	if c.uc6 != nil {
+		c.uc6.WriteToUDP(buf, mDNSAddr6)
+	}
+
+	return nil
+}

go.mod

@@ -2,4 +2,10 @@ module maze.io/x/esphome
 
 go 1.13
 
-require github.com/golang/protobuf v1.3.2
+require (
+	github.com/golang/protobuf v1.3.2
+	github.com/miekg/dns v1.1.27
+	golang.org/x/crypto v0.0.0-20200117160349-530e935923ad // indirect
+	golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa // indirect
+	golang.org/x/sys v0.0.0-20200124204421-9fbb57f87de9 // indirect
+)

go.sum

@@ -1,2 +1,27 @@
 github.com/golang/protobuf v1.3.2 h1:6nsPYzhq5kReh6QImI3k5qWzO4PEbvbIW2cwSfR/6xs=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/miekg/dns v1.1.27 h1:aEH/kqUzUxGJ/UHcEKdJY+ugH6WEzsEBBSPa8zuy1aM=
+github.com/miekg/dns v1.1.27/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20200117160349-530e935923ad h1:Jh8cai0fqIK+f6nG0UgPW5wFk8wmiMhM3AyciDBdtQg=
+golang.org/x/crypto v0.0.0-20200117160349-530e935923ad/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20190923162816-aa69164e4478 h1:l5EDrHhldLYb3ZRHDUhXF7Om7MvYXnkV9/iQNo1lX6g=
+golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa h1:F+8P+gmewFQYRk6JoLQLwjBCTu3mcIURZfNkVweuRKA=
+golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe h1:6fAMxZRR6sl1Uq8U61gxU+kPTs2tR8uOySCbBP7BN/M=
+golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200124204421-9fbb57f87de9 h1:1/DFK4b7JH8DmkqhUk48onnSfrPzImPoVxuomtbT2nk=
+golang.org/x/sys v0.0.0-20200124204421-9fbb57f87de9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=