extend attributes proto for Prefix SID support

Signed-off-by: Serguei Bezverkhi <sbezverk@cisco.com>

1 files changed, 139 insertions, 4 deletions

diff --git a/pkg/packet/bgp/prefix_sid.go b/pkg/packet/bgp/prefix_sid.go
index 7dd90082..a7983bcd 100644
--- a/pkg/packet/bgp/prefix_sid.go
+++ b/pkg/packet/bgp/prefix_sid.go
@@ -5,6 +5,10 @@ import (
 	"encoding/binary"
 	"encoding/json"
 	"fmt"
+	"net"
+
+	"github.com/golang/protobuf/ptypes"
+	api "github.com/osrg/gobgp/api"
 )
 
 const (
@@ -14,9 +18,8 @@ const (
 type TLVType uint8
 
 type TLV struct {
-	Type     TLVType
-	Length   uint16
-	Reserved uint8
+	Type   TLVType
+	Length uint16
 }
 
 func (s *TLV) Len() int {
@@ -391,7 +394,7 @@ func (s *SRv6InformationSubTLV) MarshalJSON() ([]byte, error) {
 
 func (s *SRv6InformationSubTLV) String() string {
 	var buf bytes.Buffer
-	buf.WriteString(fmt.Sprintf("SID: %s ", string(s.SID)))
+	buf.WriteString(fmt.Sprintf("SID: %s ", net.IP(s.SID).To16().String()))
 	buf.WriteString(fmt.Sprintf("Flag: %d ", s.Flags))
 	buf.WriteString(fmt.Sprintf("Endpoint Behavior: %d ", s.EndpointBehavior))
 	for _, tlv := range s.SubSubTLVs {
@@ -540,3 +543,135 @@ func (s *SRv6SIDStructureSubSubTLV) String() string {
 		s.TranspositionOffset,
 	)
 }
+
+func NewPathAttributePrefixSID(psid *api.PrefixSID) (*PathAttributePrefixSID, error) {
+	t := BGP_ATTR_TYPE_PREFIX_SID
+	s := &PathAttributePrefixSID{
+		PathAttribute: PathAttribute{
+			Flags: PathAttrFlags[t],
+			Type:  t,
+		},
+		TLVs: make([]PrefixSIDTLVInterface, 0),
+	}
+	for _, raw := range psid.Tlvs {
+		var tlv ptypes.DynamicAny
+		if err := ptypes.UnmarshalAny(raw, &tlv); err != nil {
+			return nil, err
+		}
+		switch v := tlv.Message.(type) {
+		case *api.SRv6L3ServiceTLV:
+			tlvLength, tlvs, err := UnmarshalSubTLVs(v.SubTlvs)
+			if err != nil {
+				return nil, err
+			}
+			o := &SRv6L3ServiceAttribute{
+				TLV: TLV{
+					Type:   TLVType(5),
+					Length: tlvLength,
+				},
+			}
+			s.PathAttribute.Length += tlvLength
+			// Storing Sub TLVs in a Service TLV
+			o.SubTLVs = append(o.SubTLVs, tlvs...)
+			// Adding Service TLV to Path Attribute TLV slice.
+			s.TLVs = append(s.TLVs, o)
+		default:
+			return nil, fmt.Errorf("unknown or not implemented Prefix SID type: %+v", v)
+		}
+	}
+	// Final Path Attribute Length is 3 bytes of the header and 1 byte Reserved1
+	s.PathAttribute.Length += (3 + 1)
+	return s, nil
+}
+
+func UnmarshalSubTLVs(stlvs map[uint32]*api.SRv6TLV) (uint16, []PrefixSIDTLVInterface, error) {
+	p := make([]PrefixSIDTLVInterface, 0, len(stlvs))
+	l := uint16(0)
+	// v.SubTlvs is a map by sub tlv type and the value is a slice of sub tlvs of the specific type
+	for t, tlv := range stlvs {
+		switch t {
+		case 1:
+			// Sub TLV Type 1 is SRv6 Informational Sub TLV
+			for _, stlvRaw := range tlv.Tlv {
+				// Instantiating Information Sub TLV
+				info := &SRv6InformationSubTLV{
+					SubTLV: SubTLV{
+						Type: SubTLVType(1),
+					},
+					SubSubTLVs: make([]PrefixSIDTLVInterface, 0),
+				}
+				var raw ptypes.DynamicAny
+				if err := ptypes.UnmarshalAny(stlvRaw, &raw); err != nil {
+					return 0, nil, err
+				}
+				infoProto := raw.Message.(*api.SRv6InformationSubTLV)
+				info.SID = make([]byte, len(infoProto.Sid))
+				copy(info.SID, infoProto.Sid)
+				// TODO Once RFC is published add processing of flags
+				info.Flags = 0
+				info.EndpointBehavior = uint16(infoProto.EndpointBehavior)
+				var sstlvslength uint16
+				var sstlvs []PrefixSIDTLVInterface
+				if len(infoProto.SubSubTlvs) != 0 {
+					// Processing Sub Sub TLVs
+					var err error
+					sstlvslength, sstlvs, err = UnmarshalSubSubTLVs(infoProto.SubSubTlvs)
+					if err != nil {
+						return 0, nil, err
+					}
+					info.SubSubTLVs = append(info.SubSubTLVs, sstlvs...)
+				}
+				// SRv6 Information Sub TLV length consists 1 byte Resrved2, 16 bytes SID, 1 byte flags, 2 bytes Endpoint Behavior
+				// 1 byte Reserved3 and length of Sub Sub TLVs
+				info.SubTLV.Length = 1 + 16 + 1 + 2 + 1 + sstlvslength
+				// For total Srv6 Information Sub TLV length, adding 3 bytes of the Sub TLV header
+				l += info.SubTLV.Length + 4
+				p = append(p, info)
+			}
+		default:
+			return 0, nil, fmt.Errorf("unknown or not implemented Prefix SID Sub TLV type: %d", t)
+		}
+	}
+
+	return l, p, nil
+}
+
+func UnmarshalSubSubTLVs(stlvs map[uint32]*api.SRv6TLV) (uint16, []PrefixSIDTLVInterface, error) {
+	p := make([]PrefixSIDTLVInterface, 0)
+	l := uint16(0)
+	// v.SubTlvs is a map by sub tlv type and the value is a slice of sub tlvs of the specific type
+	for t, tlv := range stlvs {
+		switch t {
+		case 1:
+			// Sub Sub TLV Type 1 is SRv6 Structure Sub Sub TLV
+			for _, stlvRaw := range tlv.Tlv {
+				// Instantiating Information Sub TLV
+				structure := &SRv6SIDStructureSubSubTLV{
+					SubSubTLV: SubSubTLV{
+						Type:   SubSubTLVType(1),
+						Length: 6,
+					},
+				}
+				var raw ptypes.DynamicAny
+				if err := ptypes.UnmarshalAny(stlvRaw, &raw); err != nil {
+					return 0, nil, err
+				}
+				structureProto := raw.Message.(*api.SRv6StructureSubSubTLV)
+				structure.LocalBlockLength = uint8(structureProto.LocalBlockLength)
+				structure.LocatorNodeLength = uint8(structureProto.LocalNodeLength)
+				structure.FunctionLength = uint8(structureProto.FunctionLength)
+				structure.ArgumentLength = uint8(structureProto.ArgumentLength)
+				structure.TranspositionLength = uint8(structureProto.TranspositionLength)
+				structure.TranspositionOffset = uint8(structureProto.TranspositionOffset)
+
+				// SRv6 Structure Sub Sub TLV length consists of header 3 bytes, 6 bytes of value
+				l += (3 + 6)
+				p = append(p, structure)
+			}
+		default:
+			return 0, nil, fmt.Errorf("unknown or not implemented Prefix SID Sub TLV type: %d", t)
+		}
+	}
+
+	return l, p, nil
+}