pkg/a2s: Remove unused package

1 files changed, 0 insertions, 201 deletions

diff --git a/pkg/a2s/a2s.go b/pkg/a2s/a2s.go
deleted file mode 100644
index 11cfc7c..0000000
--- a/pkg/a2s/a2s.go
+++ /dev/null
@@ -1,201 +0,0 @@
-// Package a2s implements a small portion of the r2 netchannel used by Northstar
-// to probe servers.
-package a2s
-
-import (
-	"bytes"
-	"crypto/aes"
-	"crypto/cipher"
-	"crypto/hmac"
-	"crypto/rand"
-	"crypto/sha256"
-	"encoding/binary"
-	"encoding/json"
-	"errors"
-	"fmt"
-	"net"
-	"net/netip"
-	"os"
-	"time"
-)
-
-const ProbeUID uint64 = 1000000001337
-
-var ErrTimeout = errors.New("connection timed out")
-
-func Probe(addr netip.AddrPort, timeout time.Duration) error {
-	conn, err := net.DialUDP("udp", nil, net.UDPAddrFromAddrPort(addr))
-	if err != nil {
-		return fmt.Errorf("connect to server: %w", err)
-	}
-	defer conn.Close()
-
-	t := time.Now().Add(timeout)
-	conn.SetWriteDeadline(t)
-	conn.SetReadDeadline(t)
-
-	pkt, err := r2cryptoEncrypt(r2encodeGetChallenge(ProbeUID))
-	if err != nil {
-		return fmt.Errorf("encrypt connection packet: %w", err)
-	}
-	if _, err := conn.Write(pkt); err != nil {
-		if errors.Is(err, os.ErrDeadlineExceeded) {
-			err = fmt.Errorf("%w: %v", ErrTimeout, err)
-		}
-		return fmt.Errorf("send connection packet: %w", err)
-	}
-
-	resp := make([]byte, 1500)
-	if n, err := conn.Read(resp); err != nil {
-		if errors.Is(err, os.ErrDeadlineExceeded) {
-			err = fmt.Errorf("%w: %v", ErrTimeout, err)
-		}
-		return fmt.Errorf("receive packet: %w", err)
-	} else {
-		resp = resp[:n]
-	}
-
-	dec, err := r2cryptoDecrypt(resp)
-	if err != nil {
-		return fmt.Errorf("failed to decrypt received packet: %w", err)
-	}
-
-	uid, _, err := r2decodeChallenge(dec)
-	if err != nil {
-		return fmt.Errorf("invalid challenge: %w", err)
-	}
-	if uid != ProbeUID {
-		return fmt.Errorf("invalid challenge")
-	}
-	return nil
-}
-
-func AtlasSigreq1(addr netip.AddrPort, timeout time.Duration, key string, obj any) error {
-	// TODO: unconnected udp for performance
-
-	a := net.UDPAddrFromAddrPort(addr)
-	conn, err := net.DialUDP("udp", nil, a)
-	if err != nil {
-		return err
-	}
-	defer conn.Close()
-
-	t := time.Now().Add(timeout)
-	conn.SetWriteDeadline(t)
-
-	j, err := json.Marshal(obj)
-	if err != nil {
-		return err
-	}
-
-	pkt, err := r2cryptoEncrypt(r2encodeAtlasSigreq1([]byte(key), j))
-	if err != nil {
-		return fmt.Errorf("encrypt packet: %w", err)
-	}
-	if _, err := conn.Write(pkt); err != nil {
-		if errors.Is(err, os.ErrDeadlineExceeded) {
-			err = fmt.Errorf("%w: %v", ErrTimeout, err)
-		}
-		return fmt.Errorf("send packet: %w", err)
-	}
-	return nil
-}
-
-const (
-	r2cryptoNonceSize = 12
-	r2cryptoTagSize   = 16
-	r2cryptoKey       = "X3V.bXCfe3EhN'wb"
-	r2cryptoAAD       = "\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10"
-)
-
-func r2cryptoEncrypt(b []byte) ([]byte, error) {
-	pkt := make([]byte, r2cryptoNonceSize+r2cryptoTagSize+len(b))
-
-	nonce := pkt[:r2cryptoNonceSize]
-	if _, err := rand.Read(nonce); err != nil {
-		return nil, err
-	}
-
-	c, err := aes.NewCipher([]byte(r2cryptoKey))
-	if err != nil {
-		panic(err)
-	}
-
-	a, err := cipher.NewGCMWithTagSize(c, r2cryptoTagSize)
-	if err != nil {
-		panic(err)
-	}
-
-	// Go appends the ciphertext, then the tag to the dest (nonce)
-	tmp := a.Seal(nil, nonce, b, []byte(r2cryptoAAD))
-	copy(pkt[r2cryptoNonceSize:], tmp[len(b):])
-	copy(pkt[r2cryptoNonceSize+r2cryptoTagSize:], tmp)
-	return pkt, nil
-}
-
-func r2cryptoDecrypt(b []byte) ([]byte, error) {
-	if len(b) < r2cryptoNonceSize+r2cryptoTagSize+1 {
-		return nil, fmt.Errorf("packet too small")
-	}
-
-	c, err := aes.NewCipher([]byte(r2cryptoKey))
-	if err != nil {
-		panic(err)
-	}
-
-	a, err := cipher.NewGCMWithTagSize(c, r2cryptoTagSize)
-	if err != nil {
-		panic(err)
-	}
-
-	tmp := make([]byte, len(b)-r2cryptoNonceSize)
-	copy(tmp, b[r2cryptoNonceSize+r2cryptoTagSize:])
-	copy(tmp[len(tmp)-r2cryptoTagSize:], b[r2cryptoNonceSize:])
-
-	if tmp, err = a.Open(tmp[:0], b[:r2cryptoNonceSize], tmp, []byte(r2cryptoAAD)); err != nil {
-		return nil, err
-	}
-	return tmp, nil
-}
-
-func r2encodeGetChallenge(uid uint64) []byte {
-	var b bytes.Buffer
-	binary.Write(&b, binary.LittleEndian, int32(-1))
-	binary.Write(&b, binary.LittleEndian, uint8(72))
-	binary.Write(&b, binary.LittleEndian, []byte("connect\x00"))
-	binary.Write(&b, binary.LittleEndian, uint64(uid))
-	binary.Write(&b, binary.LittleEndian, uint8(2))
-	return b.Bytes()
-}
-
-func r2encodeAtlasSigreq1(key, data []byte) []byte {
-	sig := hmac.New(sha256.New, key)
-	sig.Write(data)
-
-	var b []byte
-	b = append(b, '\xFF', '\xFF', '\xFF', '\xFF') // connectionless: int32(-1)
-	b = append(b, 'T')                            // packet kind
-	b = append(b, "sigreq1\x00"...)               // packet type
-	b = sig.Sum(b)                                // sigreq1 - signature
-	b = append(b, data...)                        // sigreq1 - data
-	return b
-}
-
-func r2decodeChallenge(b []byte) (uint64, int32, error) {
-	var pkt struct {
-		Seq       int32
-		Type      uint8
-		Challenge int32
-		UID       uint64
-	}
-	if err := binary.Read(bytes.NewReader(b), binary.LittleEndian, &pkt); err != nil {
-		return 0, 0, err
-	}
-	if pkt.Seq != -1 {
-		return 0, 0, fmt.Errorf("not a connectionless packet")
-	}
-	if pkt.Type != 73 {
-		return 0, 0, fmt.Errorf("not a challenge response")
-	}
-	return pkt.UID, pkt.Challenge, nil
-}