solar-toolkit/main.go

115 lines
2.4 KiB
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package main
import (
"bufio"
"encoding/binary"
"encoding/hex"
"flag"
"fmt"
"io"
"log"
"net"
"os"
"strings"
)
const (
readBufSizeBytes = 4_096
)
func main() {
var ipAddr string
flag.StringVar(&ipAddr, "ipaddr", "", "IP address/port")
flag.Parse()
if ipAddr == "" {
flag.Usage()
os.Exit(1)
}
fmt.Println("ipAddr", ipAddr)
conn, err := net.Dial("udp", ipAddr)
if err != nil {
log.Fatalf("error dialing: %s", err)
}
defer conn.Close()
resp, err := sendAA55Command(conn, "010200", "0182")
if err != nil {
log.Fatalf("error sending command: %s", err)
}
modelName := strings.TrimSpace(string(resp[12:22]))
serialNum := string(resp[38:54])
log.Printf("modelName = %q, serialNum = %q\n", modelName, serialNum)
}
func sendAA55Command(conn io.ReadWriter, payload, expectedResponseType string) ([]byte, error) {
bytes, err := hex.DecodeString("AA55C07F" + payload)
if err != nil {
return nil, fmt.Errorf("error decoding hex string: %s", err)
}
bytes = append(bytes, checksum(bytes)...)
_, err = fmt.Fprint(conn, string(bytes))
if err != nil {
return nil, fmt.Errorf("error writing to socket: %s", err)
}
log.Printf("sent data to socket: %X", bytes)
p := make([]byte, readBufSizeBytes)
n, err := bufio.NewReader(conn).Read(p)
if err != nil {
return nil, fmt.Errorf("error reading from socket: %s", err)
}
return validateResponse(p[:n], expectedResponseType)
}
const (
aa55ResponseLengthIndex = 6
aa55ResponseLengthOffset = 9
)
func validateResponse(p []byte, expectedResponseType string) ([]byte, error) {
if len(p) < 8 {
return nil, fmt.Errorf("response truncated")
}
expectedLen := int(p[aa55ResponseLengthIndex] + aa55ResponseLengthOffset)
if len(p) != expectedLen {
return nil, fmt.Errorf("unexpected response length %d (expected %d)", len(p), expectedLen)
}
responseType := hex.EncodeToString(p[4:6])
if responseType != expectedResponseType {
return nil, fmt.Errorf("unexpected response type `%s` (expected `%s`)", responseType, expectedResponseType)
}
var s uint16
for _, b := range p[:len(p)-2] {
s += uint16(b)
}
expSum := binary.BigEndian.Uint16(p[len(p)-2:])
if s != expSum {
return nil, fmt.Errorf("invalid response checksum %d (expected %d)", s, expSum)
}
return p, nil
}
func checksum(p []byte) []byte {
var v uint16
for _, byte := range p {
v += uint16(byte)
}
c := make([]byte, 4)
binary.BigEndian.PutUint16(c, v)
return c
}