packet: add ValidateUpdateMsg

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

1 files changed, 98 insertions, 1 deletions

diff --git a/packet/validate.go b/packet/validate.go
index e3ddf58b..5711a91b 100644
--- a/packet/validate.go
+++ b/packet/validate.go
@@ -1,9 +1,107 @@
 package bgp
 
 import (
+	"github.com/osrg/gobgp/config"
 	"strconv"
 )
 
+// Validator for BGPUpdate
+func ValidateUpdateMsg(m *BGPUpdate) (bool, error) {
+	eCode := uint8(BGP_ERROR_UPDATE_MESSAGE_ERROR)
+	eSubCodeAttrList := uint8(BGP_ERROR_SUB_MALFORMED_ATTRIBUTE_LIST)
+	eSubCodeFlagsError := uint8(BGP_ERROR_SUB_ATTRIBUTE_FLAGS_ERROR)
+	eSubCodeInvalidNetField := uint8(BGP_ERROR_SUB_INVALID_NETWORK_FIELD)
+	eSubCodeMissing := uint8(BGP_ERROR_SUB_MISSING_WELL_KNOWN_ATTRIBUTE)
+
+	seen := make(map[BGPAttrType]PathAttributeInterface)
+	// check path attribute
+	for _, a := range m.PathAttributes {
+
+		// check attribute flags
+		ok, eMsg := ValidateFlags(a.getType(), a.getFlags())
+		if !ok {
+			data, _ := a.Serialize()
+			return false, NewMessageError(eCode, eSubCodeFlagsError, data, eMsg)
+		}
+
+		// check duplication
+		if _, ok := seen[a.getType()]; !ok {
+			seen[a.getType()] = a
+		} else {
+			eMsg := "the path attribute apears twice. Type : " + strconv.Itoa(int(a.getType()))
+			return false, NewMessageError(eCode, eSubCodeAttrList, nil, eMsg)
+		}
+
+		// check specific path attribute
+		ok, e := ValidateAttribute(a)
+		if !ok {
+			return false, e
+		}
+	}
+
+	// check the existence of well-known mandatory attributes
+	exist := func(attrs []BGPAttrType) (bool, BGPAttrType) {
+		for _, attr := range attrs {
+			_, ok := seen[attr]
+			if !ok {
+				return false, attr
+			}
+		}
+		return true, 0
+	}
+	mandatory := []BGPAttrType{BGP_ATTR_TYPE_ORIGIN, BGP_ATTR_TYPE_AS_PATH, BGP_ATTR_TYPE_NEXT_HOP}
+	if ok, t := exist(mandatory); !ok {
+		eMsg := "well-known mandatory attributes are not present. type : " + strconv.Itoa(int(t))
+		data := []byte{byte(t)}
+		return false, NewMessageError(eCode, eSubCodeMissing, data, eMsg)
+	}
+
+	// check NLRI
+	for _, n := range m.NLRI {
+		if n.Prefix.To4() == nil {
+			eMsg := "invalid nlri"
+			return false, NewMessageError(eCode, eSubCodeInvalidNetField, nil, eMsg)
+		}
+	}
+
+	return true, nil
+}
+
+func ValidateAttribute(a PathAttributeInterface) (bool, error) {
+
+	eCode := uint8(BGP_ERROR_UPDATE_MESSAGE_ERROR)
+	eSubCodeBadOrigin := uint8(BGP_ERROR_SUB_INVALID_ORIGIN_ATTRIBUTE)
+	eSubCodeBadNextHop := uint8(BGP_ERROR_SUB_INVALID_NEXT_HOP_ATTRIBUTE)
+	eSubCodeUnknown := uint8(BGP_ERROR_SUB_UNRECOGNIZED_WELL_KNOWN_ATTRIBUTE)
+
+	switch p := a.(type) {
+	case *PathAttributeOrigin:
+		v := uint8(p.Value[0])
+		if v != config.BGP_ORIGIN_ATTR_TYPE_IGP &&
+			v != config.BGP_ORIGIN_ATTR_TYPE_EGP &&
+			v != config.BGP_ORIGIN_ATTR_TYPE_INCOMPLETE {
+			eMsg := "invalid origin attribute. value : " + strconv.Itoa(int(v))
+			return false, NewMessageError(eCode, eSubCodeBadOrigin, nil, eMsg)
+		}
+	case *PathAttributeNextHop:
+		//check IP address syntax
+		if p.Value.To4() == nil {
+			eMsg := "invalid nexthop address"
+			data, _ := a.Serialize()
+			return false, NewMessageError(eCode, eSubCodeBadNextHop, data, eMsg)
+		}
+	case *PathAttributeUnknown:
+		if p.getFlags()&BGP_ATTR_FLAG_OPTIONAL == 0 {
+			eMsg := "unrecognized well-known attribute"
+			data, _ := a.Serialize()
+			return false, NewMessageError(eCode, eSubCodeUnknown, data, eMsg)
+		}
+	}
+
+	return true, nil
+
+}
+
 // validator for PathAttribute
 func ValidateFlags(t BGPAttrType, flags uint8) (bool, string) {
 
@@ -28,7 +126,6 @@ func ValidateFlags(t BGPAttrType, flags uint8) (bool, string) {
 	}
 
 	// check flags are correct
-
 	if f, ok := pathAttrFlags[t]; ok {
 		if f != flags {
 			eMsg := "flags are invalid. attribtue type : " + strconv.Itoa(int(t))