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Diffstat (limited to 'pkg/packet/bgp/bgp.go')
-rw-r--r--pkg/packet/bgp/bgp.go107
1 files changed, 101 insertions, 6 deletions
diff --git a/pkg/packet/bgp/bgp.go b/pkg/packet/bgp/bgp.go
index 84604312..f72a3706 100644
--- a/pkg/packet/bgp/bgp.go
+++ b/pkg/packet/bgp/bgp.go
@@ -31,7 +31,8 @@ import (
)
type MarshallingOption struct {
- AddPath map[RouteFamily]BGPAddPathMode
+ AddPath map[RouteFamily]BGPAddPathMode
+ Attributes map[BGPAttrType]bool
}
func IsAddPathEnabled(decode bool, f RouteFamily, options []*MarshallingOption) bool {
@@ -49,6 +50,18 @@ func IsAddPathEnabled(decode bool, f RouteFamily, options []*MarshallingOption)
}
return false
}
+func IsAttributePresent(attr BGPAttrType, options []*MarshallingOption) bool {
+ for _, opt := range options {
+ if opt == nil {
+ continue
+ }
+ if o := opt.Attributes; o != nil {
+ _, ok := o[attr]
+ return ok
+ }
+ }
+ return false
+}
const (
AFI_IP = 1
@@ -1588,9 +1601,17 @@ type MPLSLabelStack struct {
Labels []uint32
}
-func (l *MPLSLabelStack) DecodeFromBytes(data []byte) error {
+func (l *MPLSLabelStack) DecodeFromBytes(data []byte, options ...*MarshallingOption) error {
labels := []uint32{}
foundBottom := false
+ bottomExpected := true
+ if IsAttributePresent(BGP_ATTR_TYPE_PREFIX_SID, options) {
+ // If Update carries Prefix SID attribute then there is no a label stack,
+ // but just 3 bytes which are used to carry the lower portion of Prefix SID.
+ // There is no bottom stack indication in this case. Once 3 bytes are stored
+ // breaking out of the loop.
+ bottomExpected = false
+ }
for len(data) >= 3 {
label := uint32(data[0])<<16 | uint32(data[1])<<8 | uint32(data[2])
if label == WITHDRAW_LABEL || label == ZERO_LABEL {
@@ -1599,6 +1620,11 @@ func (l *MPLSLabelStack) DecodeFromBytes(data []byte) error {
}
data = data[3:]
labels = append(labels, label>>4)
+ if !bottomExpected {
+ // Faking found bottom.
+ foundBottom = true
+ break
+ }
if label&1 == 1 {
foundBottom = true
break
@@ -1613,7 +1639,7 @@ func (l *MPLSLabelStack) DecodeFromBytes(data []byte) error {
return nil
}
-func (l *MPLSLabelStack) Serialize() ([]byte, error) {
+func (l *MPLSLabelStack) Serialize(options ...*MarshallingOption) ([]byte, error) {
buf := make([]byte, len(l.Labels)*3)
for i, label := range l.Labels {
if label == WITHDRAW_LABEL {
@@ -1624,6 +1650,13 @@ func (l *MPLSLabelStack) Serialize() ([]byte, error) {
buf[i*3+1] = byte((label >> 8) & 0xff)
buf[i*3+2] = byte(label & 0xff)
}
+ if IsAttributePresent(BGP_ATTR_TYPE_PREFIX_SID, options) {
+ // If Update carries Prefix SID attribute then there is no a label stack,
+ // but just 3 bytes which are used to carry the lower portion of Prefix SID.
+ // No need BoS bit set
+ return buf, nil
+ }
+
buf[len(buf)-1] |= 1
return buf, nil
}
@@ -1721,7 +1754,7 @@ func (l *LabeledVPNIPAddrPrefix) DecodeFromBytes(data []byte, options ...*Marsha
}
l.Length = uint8(data[0])
data = data[1:]
- l.Labels.DecodeFromBytes(data)
+ l.Labels.DecodeFromBytes(data, options...)
if int(l.Length)-8*(l.Labels.Len()) < 0 {
l.Labels.Labels = []uint32{}
}
@@ -1746,7 +1779,7 @@ func (l *LabeledVPNIPAddrPrefix) Serialize(options ...*MarshallingOption) ([]byt
}
}
buf = append(buf, l.Length)
- lbuf, err := l.Labels.Serialize()
+ lbuf, err := l.Labels.Serialize(options...)
if err != nil {
return nil, err
}
@@ -8480,6 +8513,7 @@ var PathAttrFlags map[BGPAttrType]BGPAttrFlag = map[BGPAttrType]BGPAttrFlag{
BGP_ATTR_TYPE_AIGP: BGP_ATTR_FLAG_OPTIONAL,
BGP_ATTR_TYPE_LARGE_COMMUNITY: BGP_ATTR_FLAG_TRANSITIVE | BGP_ATTR_FLAG_OPTIONAL,
BGP_ATTR_TYPE_LS: BGP_ATTR_FLAG_OPTIONAL,
+ BGP_ATTR_TYPE_PREFIX_SID: BGP_ATTR_FLAG_TRANSITIVE | BGP_ATTR_FLAG_OPTIONAL,
}
// getPathAttrFlags returns BGP Path Attribute flags value from its type and
@@ -9515,6 +9549,7 @@ type PathAttributeMpReachNLRI struct {
}
func (p *PathAttributeMpReachNLRI) DecodeFromBytes(data []byte, options ...*MarshallingOption) error {
+
value, err := p.PathAttribute.DecodeFromBytes(data, options...)
if err != nil {
return err
@@ -12325,6 +12360,56 @@ func NewPathAttributeUnknown(flags BGPAttrFlag, typ BGPAttrType, value []byte) *
}
}
+// BGPUpdateAttributes defines a map with a key as bgp attribute type
+// and value as bool. Value set to true indicates that the attribute specified by the key
+// exists in the bgp update.
+type BGPUpdateAttributes struct {
+ Attribute map[BGPAttrType]bool
+}
+
+func GetBGPUpdateAttributes(data []byte) map[BGPAttrType]bool {
+ m := make(map[BGPAttrType]bool)
+ for p := 0; p < len(data); {
+ flag := data[p]
+ p++
+ if p < len(data) {
+ t := data[p]
+ m[BGPAttrType(t)] = true
+ } else {
+ break
+ }
+ p++
+ var l uint16
+ // Checking for Extened
+ if flag&0x10 == 0x10 {
+ if p+2 <= len(data) {
+ l = binary.BigEndian.Uint16(data[p : p+2])
+ } else {
+ break
+ }
+ p += 2
+ } else {
+ if p < len(data) {
+ l = uint16(data[p])
+ p++
+ } else {
+ break
+ }
+ }
+ p += int(l)
+ }
+ return m
+}
+
+func GetBGPUpdateAttributesFromMsg(msg *BGPUpdate) map[BGPAttrType]bool {
+ m := make(map[BGPAttrType]bool)
+ for _, p := range msg.PathAttributes {
+ m[p.GetType()] = true
+ }
+
+ return m
+}
+
func GetPathAttribute(data []byte) (PathAttributeInterface, error) {
if len(data) < 2 {
eCode := uint8(BGP_ERROR_UPDATE_MESSAGE_ERROR)
@@ -12440,6 +12525,11 @@ func (msg *BGPUpdate) DecodeFromBytes(data []byte, options ...*MarshallingOption
if len(data) < int(msg.TotalPathAttributeLen) {
return NewMessageError(eCode, eSubCode, nil, "path total attribute length exceeds message length")
}
+ attributes := GetBGPUpdateAttributes(data)
+ o := MarshallingOption{
+ Attributes: attributes,
+ }
+ options = append(options, &o)
msg.PathAttributes = []PathAttributeInterface{}
for pathlen := msg.TotalPathAttributeLen; pathlen > 0; {
@@ -12457,7 +12547,6 @@ func (msg *BGPUpdate) DecodeFromBytes(data []byte, options ...*MarshallingOption
if err != nil {
return err
}
-
err = p.DecodeFromBytes(data, options...)
if err != nil {
e = err.(*MessageError)
@@ -12519,6 +12608,11 @@ func (msg *BGPUpdate) Serialize(options ...*MarshallingOption) ([]byte, error) {
msg.WithdrawnRoutesLen = uint16(len(wbuf) - 2)
binary.BigEndian.PutUint16(wbuf, msg.WithdrawnRoutesLen)
+ attributes := GetBGPUpdateAttributesFromMsg(msg)
+ o := MarshallingOption{
+ Attributes: attributes,
+ }
+ options = append(options, &o)
pbuf := make([]byte, 2)
for _, p := range msg.PathAttributes {
onepbuf, err := p.Serialize(options...)
@@ -12538,6 +12632,7 @@ func (msg *BGPUpdate) Serialize(options ...*MarshallingOption) ([]byte, error) {
}
buf = append(buf, nbuf...)
}
+
return buf, nil
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-15 04:47:59 +0000