151 lines
3.4 KiB
Go
151 lines
3.4 KiB
Go
package lockserver
|
||
|
||
import (
|
||
"bufio"
|
||
"fmt"
|
||
"net"
|
||
"time"
|
||
|
||
log "github.com/sirupsen/logrus"
|
||
)
|
||
|
||
const (
|
||
STX = 0x02 // Start of Text
|
||
ETX = 0x03 // End of Text
|
||
ENQ = 0x05 // Enquiry from host
|
||
ACK = 0x06 // Positive response
|
||
NAK = 0x15 // Negative response
|
||
separator = 0xB3 // '│' character in ASCII (179 decimal)
|
||
)
|
||
|
||
// calculateLRC computes the Longitudinal Redundancy Check over data
|
||
func calculateLRC(data []byte) byte {
|
||
var lrc byte
|
||
for _, b := range data {
|
||
lrc ^= b
|
||
}
|
||
return lrc
|
||
}
|
||
|
||
// BuildCommand assembles the SALTO frame with fields #0–#10, STX/ETX and LRC
|
||
func (lock *SaltoLockServer) BuildCommand(req DoorCardRequest, checkIn, checkOut time.Time) error {
|
||
// helper: hh[mm]DDMMYY
|
||
fmtStamp := func(t time.Time) string {
|
||
return fmt.Sprintf("%02d%02d%02d%02d%02d",
|
||
t.Hour(), t.Minute(), t.Day(), int(t.Month()), t.Year()%100)
|
||
}
|
||
start := fmtStamp(checkIn)
|
||
expiry := fmtStamp(checkOut)
|
||
|
||
// command type
|
||
cmd := "CN"
|
||
if req.FollowStr == "1" {
|
||
cmd = "CC"
|
||
}
|
||
|
||
// fields 0–10
|
||
fields := []string{
|
||
cmd,
|
||
lock.encoderAddr,
|
||
"E",
|
||
req.RoomField,
|
||
"", // optional field 4
|
||
"", // 5
|
||
"", // 6
|
||
"", // 7
|
||
"", // 8
|
||
start,
|
||
expiry,
|
||
}
|
||
|
||
// build payload between STX and ETX
|
||
body := []byte{STX}
|
||
for _, f := range fields {
|
||
body = append(body, separator)
|
||
body = append(body, []byte(f)...)
|
||
}
|
||
body = append(body, separator)
|
||
body = append(body, ETX)
|
||
|
||
// append LRC (XOR of everything after STX through ETX)
|
||
lrc := calculateLRC(body[1:])
|
||
body = append(body, lrc)
|
||
|
||
lock.command = body
|
||
return nil
|
||
}
|
||
|
||
// LockSequence performs the full ENQ/ACK handshake and command exchange
|
||
func (lock *SaltoLockServer) LockSequence(conn net.Conn) error {
|
||
const timeout = 10 * time.Second
|
||
|
||
reader := bufio.NewReader(conn)
|
||
|
||
// 1. Send ENQ
|
||
if _, err := conn.Write([]byte{ENQ}); err != nil {
|
||
return fmt.Errorf("failed to send ENQ: %w", err)
|
||
}
|
||
|
||
// 2. Expect ACK
|
||
conn.SetReadDeadline(time.Now().Add(timeout))
|
||
b, err := reader.ReadByte()
|
||
if err != nil {
|
||
return fmt.Errorf("error awaiting ACK to ENQ: %w", err)
|
||
}
|
||
if b != ACK {
|
||
return fmt.Errorf("expected ACK after ENQ, got 0x%X", b)
|
||
}
|
||
|
||
// 3. Send the command frame
|
||
if _, err := conn.Write(lock.command); err != nil {
|
||
return fmt.Errorf("failed to send command frame: %w", err)
|
||
}
|
||
|
||
// 4. Expect ACK to command
|
||
conn.SetReadDeadline(time.Now().Add(timeout))
|
||
b, err = reader.ReadByte()
|
||
if err != nil {
|
||
return fmt.Errorf("error awaiting ACK to command: %w", err)
|
||
}
|
||
if b == NAK {
|
||
return fmt.Errorf("command rejected (NAK)")
|
||
} else if b != ACK {
|
||
return fmt.Errorf("expected ACK to command, got 0x%X", b)
|
||
}
|
||
|
||
// 5. Read response: expect STX
|
||
conn.SetReadDeadline(time.Now().Add(timeout))
|
||
b, err = reader.ReadByte()
|
||
if err != nil {
|
||
return fmt.Errorf("error reading response STX: %w", err)
|
||
}
|
||
if b != STX {
|
||
return fmt.Errorf("expected STX at response start, got 0x%X", b)
|
||
}
|
||
|
||
// 6. Read until ETX
|
||
var resp []byte
|
||
for {
|
||
conn.SetReadDeadline(time.Now().Add(timeout))
|
||
c, err := reader.ReadByte()
|
||
if err != nil {
|
||
return fmt.Errorf("error reading response body: %w", err)
|
||
}
|
||
resp = append(resp, c)
|
||
if c == ETX {
|
||
break
|
||
}
|
||
}
|
||
|
||
// 7. (Optional) Read LRC or final CR
|
||
conn.SetReadDeadline(time.Now().Add(timeout))
|
||
if lrc, err := reader.ReadByte(); err == nil {
|
||
resp = append(resp, lrc)
|
||
} else {
|
||
log.Warnf("LockSequence: failed to read trailing LRC/CR: %v", err)
|
||
}
|
||
|
||
log.Infof("LockSequence: received response: % X", resp)
|
||
return nil
|
||
}
|