WIP

aurp/atalk.go

@@ -0,0 +1,17 @@
+package aurp
+
+import "io"
+
+// AppleTalkPacket is for encapsulated AppleTalk traffic.
+type AppleTalkPacket struct {
+	DomainHeader // where PacketTypeAppleTalk
+
+	Data []byte
+}
+
+func (p *AppleTalkPacket) WriteTo(w io.Writer) (int64, error) {
+	a := acc(w)
+	a.writeTo(&p.DomainHeader)
+	a.write(p.Data)
+	return a.ret()
+}

aurp/aurp.go

@@ -8,34 +8,6 @@ import (
 	"io"
 )
 
-// TrHeader represent an AURP-Tr packet header. It includes the domain header.
-type TrHeader struct {
-	DomainHeader
-
-	ConnectionID uint16
-	Sequence     uint16 // Note: 65535 is succeeded by 1, not 0
-}
-
-// WriteTo writes the encoded form of the header to w, including the domain
-// header.
-func (h *TrHeader) WriteTo(w io.Writer) (int64, error) {
-	a := acc(w)
-	a.writeTo(&h.DomainHeader)
-	a.write16(h.ConnectionID)
-	a.write16(h.Sequence)
-	return a.ret()
-}
-
-func parseTrHeader(p []byte) (TrHeader, []byte, error) {
-	if len(p) < 4 {
-		return TrHeader{}, p, fmt.Errorf("insufficient input length %d for tr header", len(p))
-	}
-	return TrHeader{
-		ConnectionID: binary.BigEndian.Uint16(p[:2]),
-		Sequence:     binary.BigEndian.Uint16(p[2:4]),
-	}, p[4:], nil
-}
-
 // Header represents an AURP packet header. It includes the AURP-Tr header,
 // which includes the domain header.
 type Header struct {
@@ -86,16 +58,19 @@ const (
 type RoutingFlag uint16
 
 const (
-	// Open-Req and RI-Req
+	// Open-Req and RI-Req (SUI flags)
 	RoutingFlagSUINA      RoutingFlag = 0x4000
 	RoutingFlagSUINDOrNRC RoutingFlag = 0x2000
 	RoutingFlagSUINDC     RoutingFlag = 0x1000
 	RoutingFlagSUIZC      RoutingFlag = 0x0800
 
+	// The combination of the above four flags (the SUI flags).
+	RoutingFlagAllSUI RoutingFlag = 0x7800
+
 	// RI-Rsp and GDZL-Rsp
 	RoutingFlagLast RoutingFlag = 0x8000
 
-	// Open-Rsp
+	// Open-Rsp (environment flags)
 	RoutingFlagRemappingActive   RoutingFlag = 0x4000
 	RoutingFlagHopCountReduction RoutingFlag = 0x2000
 	RoutingFlagReservedEnv       RoutingFlag = 0x1800
@@ -110,20 +85,6 @@ type Packet interface {
 	io.WriterTo
 }
 
-// AppleTalkPacket is for encapsulated AppleTalk traffic.
-type AppleTalkPacket struct {
-	DomainHeader // where PacketTypeAppleTalk
-
-	Data []byte
-}
-
-func (p *AppleTalkPacket) WriteTo(w io.Writer) (int64, error) {
-	a := acc(w)
-	a.writeTo(&p.DomainHeader)
-	a.write(p.Data)
-	return a.ret()
-}
-
 // ParsePacket parses the body of a UDP packet for a domain header, and then
 // based on the packet type, an AURP-Tr header, an AURP routing header, and
 // then a particular packet type.

aurp/domain.go

@@ -13,7 +13,7 @@ type DomainHeader struct {
 	DestinationDI DomainIdentifier
 	SourceDI      DomainIdentifier
 	Version       uint16     // Should always be 0x0001
-	Reserved      uint16
+	Reserved      uint16     // Should always be 0x0000
 	PacketType    PacketType // 2 = AppleTalk data packet, 3 = AURP packet
 }
 

aurp/open.go

@@ -15,9 +15,6 @@ type OpenReqPacket struct {
 }
 
 func (p *OpenReqPacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeOpenReq
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(p.Version)
@@ -48,9 +45,6 @@ type OpenRspPacket struct {
 }
 
 func (p *OpenRspPacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeOpenRsp
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.RateOrErrCode))

aurp/router_down.go

@@ -13,8 +13,6 @@ type RDPacket struct {
 }
 
 func (p *RDPacket) WriteTo(w io.Writer) (int64, error) {
-	p.CommandCode = CmdCodeRD
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.ErrorCode))

aurp/routing_info.go

@@ -10,12 +10,6 @@ type RIReqPacket struct {
 	Header
 }
 
-func (p *RIReqPacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeRIReq
-	return p.Header.WriteTo(w)
-}
-
 type RIRspPacket struct {
 	Header
 
@@ -23,8 +17,6 @@ type RIRspPacket struct {
 }
 
 func (p *RIRspPacket) WriteTo(w io.Writer) (int64, error) {
-	p.CommandCode = CmdCodeRIRsp
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.writeTo(p.Networks)
@@ -45,11 +37,6 @@ type RIAckPacket struct {
 	Header
 }
 
-func (p *RIAckPacket) WriteTo(w io.Writer) (int64, error) {
-	p.CommandCode = CmdCodeRIAck
-	return p.Header.WriteTo(w)
-}
-
 type RIUpdPacket struct {
 	Header
 
@@ -57,8 +44,6 @@ type RIUpdPacket struct {
 }
 
 func (p *RIUpdPacket) WriteTo(w io.Writer) (int64, error) {
-	p.CommandCode = CmdCodeRIUpd
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.writeTo(p.Events)

aurp/tickle.go

@@ -1,25 +1,9 @@
 package aurp
 
-import "io"
-
 type TicklePacket struct {
 	Header
 }
 
-func (p *TicklePacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeTickle
-	p.Flags = 0
-	return p.Header.WriteTo(w)
-}
-
 type TickleAckPacket struct {
 	Header
 }
-
-func (p *TickleAckPacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeTickleAck
-	p.Flags = 0
-	return p.Header.WriteTo(w)
-}

aurp/transport.go

@@ -0,0 +1,99 @@
+package aurp
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+// TrHeader represent an AURP-Tr packet header. It includes the domain header.
+type TrHeader struct {
+	DomainHeader
+
+	ConnectionID uint16
+	Sequence     uint16
+}
+
+// WriteTo writes the encoded form of the header to w, including the domain
+// header.
+func (h *TrHeader) WriteTo(w io.Writer) (int64, error) {
+	a := acc(w)
+	a.writeTo(&h.DomainHeader)
+	a.write16(h.ConnectionID)
+	a.write16(h.Sequence)
+	return a.ret()
+}
+
+func parseTrHeader(p []byte) (TrHeader, []byte, error) {
+	if len(p) < 4 {
+		return TrHeader{}, p, fmt.Errorf("insufficient input length %d for tr header", len(p))
+	}
+	return TrHeader{
+		ConnectionID: binary.BigEndian.Uint16(p[:2]),
+		Sequence:     binary.BigEndian.Uint16(p[2:4]),
+	}, p[4:], nil
+}
+
+// incSequence increments the sequence number.
+// Note that 0 is special and 65535+1 = 1, according to AURP.
+func (tr *TrHeader) incSequence() {
+	tr.Sequence++
+	if tr.Sequence == 0 {
+		tr.Sequence = 1
+	}
+}
+
+// transaction returns a new TrHeader based on this one, usable for transaction
+// requests or responses.
+func (tr *TrHeader) transaction() TrHeader {
+	return TrHeader{
+		DomainHeader: DomainHeader{
+			DestinationDI: tr.DestinationDI,
+			SourceDI:      tr.SourceDI,
+			Version:       1,
+			Reserved:      0,
+			PacketType:    PacketTypeRouting,
+		},
+		ConnectionID: tr.ConnectionID,
+		Sequence:     0, // Transaction packets all use sequence number 0.
+	}
+}
+
+// DataSender is used to track sender state in a one-way AURP connection.
+// Note that both data senders and data recievers can send packets.
+type DataSender struct {
+	TrHeader
+}
+
+// NewOpenRspPacket returns a new Open-Rsp packet structure.
+func (ds *DataSender) NewOpenRspPacket(envFlags RoutingFlag, rateOrErr int16, opts Options) *OpenRspPacket {
+	return &OpenRspPacket{
+		Header: Header{
+			TrHeader:    ds.transaction(),
+			CommandCode: CmdCodeOpenRsp,
+			Flags:       envFlags,
+		},
+		RateOrErrCode: rateOrErr,
+		Options:       opts,
+	}
+}
+
+// DataReceiver is used to track reciever state in a one-way AURP connection.
+// Note that both data senders and data recievers can send packets.
+type DataReceiver struct {
+	TrHeader
+}
+
+// NewOpenReqPacket returns a new Open-Req packet structure. By default it sets
+// all SUI flags and uses version 1.
+func (dr *DataReceiver) NewOpenReqPacket(opts Options) *OpenReqPacket {
+	return &OpenReqPacket{
+		Header: Header{
+			TrHeader:    dr.transaction(),
+			CommandCode: CmdCodeOpenReq,
+			Flags:       RoutingFlagAllSUI,
+		},
+		Version: 1,
+		Options: opts,
+	}
+}

aurp/zone_info.go

@@ -32,11 +32,6 @@ type ZIReqPacket struct {
 }
 
 func (p *ZIReqPacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeZoneReq
-	p.Flags = 0
-	p.Subcode = SubcodeZoneInfoReq
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.Subcode))
@@ -79,11 +74,6 @@ type ZIRspPacket struct {
 }
 
 func (p *ZIRspPacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeZoneRsp
-	p.Flags = 0
-	// Subcode can vary for this packet type: it's either 1 or 2
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.Subcode))
@@ -109,11 +99,6 @@ type GDZLReqPacket struct {
 }
 
 func (p *GDZLReqPacket) WriteTo(w io.Writer) (int64, error) {
-	p.Sequence = 0
-	p.CommandCode = CmdCodeZoneReq
-	p.Flags = 0
-	p.Subcode = SubcodeGetDomainZoneList
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.Subcode))
@@ -145,11 +130,6 @@ func (p *GDZLRspPacket) WriteTo(w io.Writer) (int64, error) {
 		}
 	}
 
-	p.Sequence = 0
-	p.CommandCode = CmdCodeZoneRsp
-	// Flags is used to distinguish the final response packet, so leave alone
-	p.Subcode = SubcodeGetDomainZoneList
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.Subcode))
@@ -207,11 +187,6 @@ func (p *GZNReqPacket) WriteTo(w io.Writer) (int64, error) {
 		return 0, fmt.Errorf("zone name %q too long", p.ZoneName)
 	}
 
-	p.Sequence = 0
-	p.CommandCode = CmdCodeZoneReq
-	p.Flags = 0
-	p.Subcode = SubcodeGetZonesNet
-
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.Subcode))