Files
go2rtc/pkg/hap/client.go
2023-12-30 20:43:40 +03:00

370 lines
7.9 KiB
Go

package hap
import (
"bufio"
"bytes"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"io"
"net"
"net/http"
"net/url"
"strings"
"time"
"github.com/AlexxIT/go2rtc/pkg/hap/chacha20poly1305"
"github.com/AlexxIT/go2rtc/pkg/hap/curve25519"
"github.com/AlexxIT/go2rtc/pkg/hap/ed25519"
"github.com/AlexxIT/go2rtc/pkg/hap/hkdf"
"github.com/AlexxIT/go2rtc/pkg/hap/secure"
"github.com/AlexxIT/go2rtc/pkg/hap/tlv8"
"github.com/AlexxIT/go2rtc/pkg/mdns"
)
const (
ConnDialTimeout = time.Second * 3
ConnDeadline = time.Second * 3
)
// Client for HomeKit. DevicePublic can be null.
type Client struct {
DeviceAddress string // including port
DeviceID string // aka. Accessory
DevicePublic []byte
ClientID string // aka. Controller
ClientPrivate []byte
OnEvent func(res *http.Response)
//Output func(msg any)
Conn net.Conn
reader *bufio.Reader
res chan *http.Response
err error
}
func NewClient(rawURL string) (*Client, error) {
u, err := url.Parse(rawURL)
if err != nil {
return nil, err
}
query := u.Query()
c := &Client{
DeviceAddress: u.Host,
DeviceID: query.Get("device_id"),
DevicePublic: DecodeKey(query.Get("device_public")),
ClientID: query.Get("client_id"),
ClientPrivate: DecodeKey(query.Get("client_private")),
}
return c, nil
}
func (c *Client) ClientPublic() []byte {
return c.ClientPrivate[32:]
}
func (c *Client) URL() string {
return fmt.Sprintf(
"homekit://%s?device_id=%s&device_public=%16x&client_id=%s&client_private=%32x",
c.DeviceAddress, c.DeviceID, c.DevicePublic, c.ClientID, c.ClientPrivate,
)
}
func (c *Client) DeviceHost() string {
if i := strings.IndexByte(c.DeviceAddress, ':'); i > 0 {
return c.DeviceAddress[:i]
}
return c.DeviceAddress
}
func (c *Client) Dial() (err error) {
if len(c.ClientID) == 0 || len(c.ClientPrivate) == 0 {
return errors.New("hap: can't dial witout client_id or client_private")
}
// update device address (host and/or port) before dial
_ = mdns.QueryOrDiscovery(c.DeviceHost(), mdns.ServiceHAP, func(entry *mdns.ServiceEntry) bool {
if entry.Complete() && entry.Info["id"] == c.DeviceID {
c.DeviceAddress = entry.Addr()
return true
}
return false
})
if c.Conn, err = net.DialTimeout("tcp", c.DeviceAddress, ConnDialTimeout); err != nil {
return
}
c.reader = bufio.NewReader(c.Conn)
// STEP M1: send our session public to device
sessionPublic, sessionPrivate := curve25519.GenerateKeyPair()
// 1. Send sessionPublic
plainM1 := struct {
PublicKey string `tlv8:"3"`
State byte `tlv8:"6"`
}{
PublicKey: string(sessionPublic),
State: StateM1,
}
res, err := c.Post(PathPairVerify, MimeTLV8, tlv8.MarshalReader(plainM1))
if err != nil {
return
}
// STEP M2: unpack deviceID from response
var cipherM2 struct {
PublicKey string `tlv8:"3"`
EncryptedData string `tlv8:"5"`
State byte `tlv8:"6"`
}
if err = tlv8.UnmarshalReader(res.Body, &cipherM2); err != nil {
return err
}
if cipherM2.State != StateM2 {
return newResponseError(plainM1, cipherM2)
}
// 1. generate session shared key
sessionShared, err := curve25519.SharedSecret(sessionPrivate, []byte(cipherM2.PublicKey))
if err != nil {
return
}
sessionKey, err := hkdf.Sha512(
sessionShared, "Pair-Verify-Encrypt-Salt", "Pair-Verify-Encrypt-Info",
)
if err != nil {
return
}
// 2. decrypt M2 response with session key
b, err := chacha20poly1305.Decrypt(sessionKey, "PV-Msg02", []byte(cipherM2.EncryptedData))
if err != nil {
return
}
// 3. unpack payload from TLV8
var plainM2 struct {
Identifier string `tlv8:"1"`
Signature string `tlv8:"10"`
}
if err = tlv8.Unmarshal(b, &plainM2); err != nil {
return
}
// 4. verify signature for M2 response with device public
// device session + device id + our session
if c.DevicePublic != nil {
b = Append(cipherM2.PublicKey, plainM2.Identifier, sessionPublic)
if !ed25519.ValidateSignature(c.DevicePublic, b, []byte(plainM2.Signature)) {
return errors.New("hap: ValidateSignature")
}
}
// STEP M3: send our clientID to device
// 1. generate signature with our private key
// (our session + our ID + device session)
b = Append(sessionPublic, c.ClientID, cipherM2.PublicKey)
if b, err = ed25519.Signature(c.ClientPrivate, b); err != nil {
return
}
// 2. generate payload
plainM3 := struct {
Identifier string `tlv8:"1"`
Signature string `tlv8:"10"`
}{
Identifier: c.ClientID,
Signature: string(b),
}
if b, err = tlv8.Marshal(plainM3); err != nil {
return
}
// 4. encrypt payload with session key
if b, err = chacha20poly1305.Encrypt(sessionKey, "PV-Msg03", b); err != nil {
return
}
// 4. generate request
cipherM3 := struct {
EncryptedData string `tlv8:"5"`
State byte `tlv8:"6"`
}{
State: StateM3,
EncryptedData: string(b),
}
if res, err = c.Post(PathPairVerify, MimeTLV8, tlv8.MarshalReader(cipherM3)); err != nil {
return
}
// STEP M4. Read response
var plainM4 struct {
State byte `tlv8:"6"`
}
if err = tlv8.UnmarshalReader(res.Body, &plainM4); err != nil {
return
}
if plainM4.State != StateM4 {
return newResponseError(cipherM3, plainM4)
}
// like tls.Client wrapper over net.Conn
if c.Conn, err = secure.Client(c.Conn, sessionShared, true); err != nil {
return
}
// new reader for new conn
c.reader = bufio.NewReader(c.Conn)
return
}
func (c *Client) Close() error {
if c.Conn == nil {
return nil
}
return c.Conn.Close()
}
func (c *Client) eventsReader() {
c.res = make(chan *http.Response)
for {
var res *http.Response
if res, c.err = ReadResponse(c.reader, nil); c.err != nil {
break
}
var body []byte
if body, c.err = io.ReadAll(res.Body); c.err != nil {
break
}
res.Body = io.NopCloser(bytes.NewReader(body))
if res.Proto != ProtoEvent {
c.res <- res
} else if c.OnEvent != nil {
c.OnEvent(res)
}
}
close(c.res)
}
func (c *Client) GetAccessories() ([]*Accessory, error) {
res, err := c.Get(PathAccessories)
if err != nil {
return nil, err
}
var v JSONAccessories
if err = json.NewDecoder(res.Body).Decode(&v); err != nil {
return nil, err
}
return v.Value, nil
}
func (c *Client) GetFirstAccessory() (*Accessory, error) {
accs, err := c.GetAccessories()
if err != nil {
return nil, err
}
if len(accs) == 0 {
return nil, errors.New("hap: GetAccessories zero answer")
}
return accs[0], nil
}
func (c *Client) GetCharacters(query string) ([]JSONCharacter, error) {
res, err := c.Get(PathCharacteristics + "?id=" + query)
if err != nil {
return nil, err
}
data, err := io.ReadAll(res.Body)
if err != nil {
return nil, err
}
var v JSONCharacters
if err = json.Unmarshal(data, &v); err != nil {
return nil, err
}
return v.Value, nil
}
func (c *Client) GetCharacter(char *Character) error {
query := fmt.Sprintf("%d.%d", DeviceAID, char.IID)
chars, err := c.GetCharacters(query)
if err != nil {
return err
}
char.Value = chars[0].Value
return nil
}
func (c *Client) PutCharacters(characters ...*Character) error {
var v JSONCharacters
for i, char := range characters {
v.Value = append(v.Value, JSONCharacter{
AID: 1,
IID: char.IID,
Value: char.Value,
})
characters[i] = char
}
body, err := json.Marshal(v)
if err != nil {
return err
}
res, err := c.Put(PathCharacteristics, MimeJSON, bytes.NewReader(body))
if err != nil {
return err
}
_, _ = io.ReadAll(res.Body) // important to "clear" body
return nil
}
func (c *Client) GetImage(width, height int) ([]byte, error) {
s := fmt.Sprintf(
`{"image-width":%d,"image-height":%d,"resource-type":"image","reason":0}`,
width, height,
)
res, err := c.Post(PathResource, MimeJSON, bytes.NewBufferString(s))
if err != nil {
return nil, err
}
return io.ReadAll(res.Body)
}
func (c *Client) LocalIP() string {
if c.Conn == nil {
return ""
}
addr := c.Conn.LocalAddr().(*net.TCPAddr)
return addr.IP.String()
}
func DecodeKey(s string) []byte {
if s == "" {
return nil
}
data, err := hex.DecodeString(s)
if err != nil {
return nil
}
return data
}