forked from osrg/gobgp
/
vpls.go
208 lines (183 loc) · 6.32 KB
/
vpls.go
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package bgp
import (
"encoding/binary"
"encoding/json"
"fmt"
)
// VPLSNLRI represents an NLRI for VPLS, as defined in [RFC 4761, section 3.2.2].
//
// Path Attribute - MP_REACH_NLRI
// Flags: 0x90, Optional, Extended-Length, Non-transitive, Complete
// Type Code: MP_REACH_NLRI (14)
// Length: 28
// Address family identifier (AFI): Layer-2 VPN (25)
// Subsequent address family identifier (SAFI): VPLS (65)
// Next hop: 192.0.2.7
// IPv4 Address: 192.0.2.7
// Number of Subnetwork points of attachment (SNPA): 0
// Network Layer Reachability Information (NLRI)
// Length: 17
// RD: 65017:104
// CE-ID: 1
// Label Block Offset: 1
// Label Block Size: 8
// Label Block Base: 800000 (bottom)
//
// [RFC 4761, section 3.2.2]: https://www.rfc-editor.org/rfc/rfc4761.html#section-3.2.2.
type VPLSNLRI struct {
PrefixDefault
VEID uint16
VEBlockOffset uint16
VEBlockSize uint16
LabelBlockBase uint32
rd RouteDistinguisherInterface
}
func (n *VPLSNLRI) DecodeFromBytes(data []byte, options ...*MarshallingOption) error {
/*
RFC6074 Section 7 BGP-AD and VPLS-BGP Interoperability
Both BGP-AD and VPLS-BGP [RFC4761] use the same AFI/SAFI. In order
for both BGP-AD and VPLS-BGP to co-exist, the NLRI length must be
used as a demultiplexer.
The BGP-AD NLRI has an NLRI length of 12 bytes, containing only an
8-byte RD and a 4-byte VSI-ID. VPLS-BGP [RFC4761] uses a 17-byte
NLRI length. Therefore, implementations of BGP-AD must ignore NLRI
that are greater than 12 bytes.
*/
length := int(binary.BigEndian.Uint16(data[0:2]))
if len(data) < length+2 {
return NewMessageError(BGP_ERROR_UPDATE_MESSAGE_ERROR, BGP_ERROR_SUB_MALFORMED_ATTRIBUTE_LIST, nil, "Not all VPLS NLRI bytes available")
}
if length == 12 { // BGP-AD
// BGP-AD is not supported yet
return nil
}
// VPLS-BGP
n.rd = GetRouteDistinguisher(data[2:10])
n.VEID = binary.BigEndian.Uint16(data[10:12])
n.VEBlockOffset = binary.BigEndian.Uint16(data[12:14])
n.VEBlockSize = binary.BigEndian.Uint16(data[14:16])
labelBlockBase := uint32(data[16])<<16 | uint32(data[17])<<8 | uint32(data[18])
n.LabelBlockBase = labelBlockBase >> 4
return nil
}
func (n *VPLSNLRI) Serialize(options ...*MarshallingOption) ([]byte, error) {
buf := make([]byte, 16)
labelBaseBuf := make([]byte, 3)
binary.BigEndian.PutUint16(buf[0:2], 17)
rdbuf, err := n.rd.Serialize()
if err != nil {
return nil, err
}
copy(buf[2:10], rdbuf[:8])
binary.BigEndian.PutUint16(buf[10:12], n.VEID)
binary.BigEndian.PutUint16(buf[12:14], n.VEBlockOffset)
binary.BigEndian.PutUint16(buf[14:16], n.VEBlockSize)
labelBlockBase := n.LabelBlockBase << 4
labelBaseBuf[0] = byte((labelBlockBase >> 16) & 0xff)
labelBaseBuf[1] = byte((labelBlockBase >> 8) & 0xff)
labelBaseBuf[2] = byte(labelBlockBase & 0xff)
return append(buf, labelBaseBuf...), nil
}
func (n *VPLSNLRI) AFI() uint16 {
return AFI_L2VPN
}
func (n *VPLSNLRI) SAFI() uint8 {
return SAFI_VPLS
}
func (n *VPLSNLRI) Len(options ...*MarshallingOption) int {
// Length (2) + Route Distinguisher (8) + VE ID (2) + VE Block Offset (2)
// + VE Block Size (2) + Label Block Base (3)
return 19
}
func (n *VPLSNLRI) String() string {
return fmt.Sprintf("%s:%d:%d (Block Size: %d, Label Block Base: %d)", n.rd, n.VEID, n.VEBlockOffset, n.VEBlockSize, n.LabelBlockBase)
}
func (n *VPLSNLRI) MarshalJSON() ([]byte, error) {
return json.Marshal(struct {
RD RouteDistinguisherInterface `json:"rd"`
VEID uint16 `json:"id"`
VEBlockOffset uint16 `json:"blockoffset"`
VEBlockSize uint16 `json:"blocksize"`
LabelBlockBase uint32 `json:"labelblockbase"`
}{
RD: n.rd,
VEID: n.VEID,
VEBlockOffset: n.VEBlockOffset,
VEBlockSize: n.VEBlockSize,
LabelBlockBase: n.LabelBlockBase,
})
}
func (n *VPLSNLRI) RD() RouteDistinguisherInterface {
return n.rd
}
func (l *VPLSNLRI) Flat() map[string]string {
return map[string]string{}
}
func NewVPLSNLRI(rd RouteDistinguisherInterface, id uint16, blockOffset uint16, blockSize uint16, labelBlockBase uint32) *VPLSNLRI {
return &VPLSNLRI{
rd: rd,
VEID: id,
VEBlockOffset: blockOffset,
VEBlockSize: blockSize,
LabelBlockBase: labelBlockBase,
}
}
// VPLSExtended repsents BGP VPLS Extended Community as described in [RFC 4761, section 3.2.4].
//
// Path Attribute - EXTENDED_COMMUNITIES
// Flags: 0xc0, Optional, Transitive, Complete
// Type Code: EXTENDED_COMMUNITIES (16)
// Length: 16
// Carried extended communities: (2 communities)
// Route Target: 65017:104 [Transitive 2-Octet AS-Specific]
// Layer2 Info: [Generic Transitive Experimental Use]
// Type: Generic Transitive Experimental Use (0x80)
// Subtype (Experimental): Layer2 Info (0x0a)
// Encaps Type: VPLS (19)
// Control Flags: 0x00
// Layer-2 MTU: 0
//
// [RFC 4761, section 3.2.4]: https://www.rfc-editor.org/rfc/rfc4761.html#section-3.2.4
type VPLSExtended struct {
SubType ExtendedCommunityAttrSubType
ControlFlags uint8
MTU uint16
}
func (e *VPLSExtended) Serialize() ([]byte, error) {
buf := make([]byte, 8)
buf[0] = byte(EC_TYPE_GENERIC_TRANSITIVE_EXPERIMENTAL)
buf[1] = byte(EC_SUBTYPE_L2_INFO)
buf[2] = byte(LAYER2ENCAPSULATION_TYPE_VPLS)
buf[3] = byte(e.ControlFlags)
binary.BigEndian.PutUint16(buf[4:6], e.MTU)
// 6-8: reserved, but Juniper says this is "site preference"
return buf, nil
}
func (e *VPLSExtended) String() string {
return fmt.Sprintf("encaps: VPLS, control flags:0x%x, mtu: %d", e.ControlFlags, e.MTU)
}
func (e *VPLSExtended) MarshalJSON() ([]byte, error) {
t, s := e.GetTypes()
return json.Marshal(struct {
Type ExtendedCommunityAttrType `json:"type"`
Subtype ExtendedCommunityAttrSubType `json:"subtype"`
Value string `json:"value"`
}{
Type: t,
Subtype: s,
Value: e.String(),
})
}
func (e *VPLSExtended) GetTypes() (ExtendedCommunityAttrType, ExtendedCommunityAttrSubType) {
return EC_TYPE_GENERIC_TRANSITIVE_EXPERIMENTAL, EC_SUBTYPE_L2_INFO
}
func (e *VPLSExtended) Flat() map[string]string {
return map[string]string{}
}
func NewVPLSExtended(flags uint8, mtu uint16) *VPLSExtended {
return &VPLSExtended{
SubType: EC_SUBTYPE_L2_INFO,
ControlFlags: flags,
MTU: mtu,
}
}