AmneziaWG v1.5 (#84)

device/awg/awg.go

@@ -0,0 +1,144 @@
+package awg
+
+import (
+	"bytes"
+	"fmt"
+	"slices"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/tevino/abool"
+)
+
+type aSecCfgType struct {
+	IsSet                      bool
+	JunkPacketCount            int
+	JunkPacketMinSize          int
+	JunkPacketMaxSize          int
+	InitHeaderJunkSize         int
+	ResponseHeaderJunkSize     int
+	CookieReplyHeaderJunkSize  int
+	TransportHeaderJunkSize    int
+	InitPacketMagicHeader      uint32
+	ResponsePacketMagicHeader  uint32
+	UnderloadPacketMagicHeader uint32
+	TransportPacketMagicHeader uint32
+	// InitPacketMagicHeader      Limit
+	// ResponsePacketMagicHeader  Limit
+	// UnderloadPacketMagicHeader Limit
+	// TransportPacketMagicHeader Limit
+}
+
+type Limit struct {
+	Min        uint32
+	Max        uint32
+	HeaderType uint32
+}
+
+func NewLimit(min, max, headerType uint32) (Limit, error) {
+	if min > max {
+		return Limit{}, fmt.Errorf("min (%d) cannot be greater than max (%d)", min, max)
+	}
+
+	return Limit{
+		Min:        min,
+		Max:        max,
+		HeaderType: headerType,
+	}, nil
+}
+
+func ParseMagicHeader(key, value string, defaultHeaderType uint32) (Limit, error) {
+	// tempAwg.ASecCfg.InitPacketMagicHeader, err = awg.NewLimit(uint32(initPacketMagicHeaderMin), uint32(initPacketMagicHeaderMax), DNewLimit(min, max, headerType)efaultMessageInitiationType)
+	// var min, max, headerType uint32
+	// _, err := fmt.Sscanf(value, "%d-%d:%d", &min, &max, &headerType)
+	// if err != nil {
+	// 	return Limit{}, fmt.Errorf("invalid magic header format: %s", value)
+	// }
+
+	limits := strings.Split(value, "-")
+	if len(limits) != 2 {
+		return Limit{}, fmt.Errorf("invalid format for key: %s; %s", key, value)
+	}
+
+	min, err := strconv.ParseUint(limits[0], 10, 32)
+	if err != nil {
+		return Limit{}, fmt.Errorf("parse min key: %s; value: ; %w", key, limits[0], err)
+	}
+
+	max, err := strconv.ParseUint(limits[1], 10, 32)
+	if err != nil {
+		return Limit{}, fmt.Errorf("parse max key: %s; value: ; %w", key, limits[0], err)
+	}
+
+	limit, err := NewLimit(uint32(min), uint32(max), defaultHeaderType)
+	if err != nil {
+		return Limit{}, fmt.Errorf("new lmit key: %s; value: ; %w", key, limits[0], err)
+	}
+
+	return limit, nil
+}
+
+type Limits []Limit
+
+func NewLimits(limits []Limit) Limits {
+	slices.SortFunc(limits, func(a, b Limit) int {
+		if a.Min < b.Min {
+			return -1
+		} else if a.Min > b.Min {
+			return 1
+		}
+		return 0
+	})
+
+	return Limits(limits)
+}
+
+type Protocol struct {
+	IsASecOn abool.AtomicBool
+	// TODO: revision the need of the mutex
+	ASecMux     sync.RWMutex
+	ASecCfg     aSecCfgType
+	JunkCreator junkCreator
+
+	HandshakeHandler SpecialHandshakeHandler
+}
+
+func (protocol *Protocol) CreateInitHeaderJunk() ([]byte, error) {
+	return protocol.createHeaderJunk(protocol.ASecCfg.InitHeaderJunkSize)
+}
+
+func (protocol *Protocol) CreateResponseHeaderJunk() ([]byte, error) {
+	return protocol.createHeaderJunk(protocol.ASecCfg.ResponseHeaderJunkSize)
+}
+
+func (protocol *Protocol) CreateCookieReplyHeaderJunk() ([]byte, error) {
+	return protocol.createHeaderJunk(protocol.ASecCfg.CookieReplyHeaderJunkSize)
+}
+
+func (protocol *Protocol) CreateTransportHeaderJunk(packetSize int) ([]byte, error) {
+	return protocol.createHeaderJunk(protocol.ASecCfg.TransportHeaderJunkSize, packetSize)
+}
+
+func (protocol *Protocol) createHeaderJunk(junkSize int, optExtraSize ...int) ([]byte, error) {
+	extraSize := 0
+	if len(optExtraSize) == 1 {
+		extraSize = optExtraSize[0]
+	}
+
+	var junk []byte
+	protocol.ASecMux.RLock()
+	if junkSize != 0 {
+		buf := make([]byte, 0, junkSize+extraSize)
+		writer := bytes.NewBuffer(buf[:0])
+		err := protocol.JunkCreator.AppendJunk(writer, junkSize)
+		if err != nil {
+			protocol.ASecMux.RUnlock()
+			return nil, err
+		}
+		junk = writer.Bytes()
+	}
+	protocol.ASecMux.RUnlock()
+
+	return junk, nil
+}