diff options
Diffstat (limited to 'packet/bgp/validate.go')
| -rw-r--r-- | packet/bgp/validate.go | 61 |
1 files changed, 54 insertions, 7 deletions
diff --git a/packet/bgp/validate.go b/packet/bgp/validate.go index 424047a5..ecc67067 100644 --- a/packet/bgp/validate.go +++ b/packet/bgp/validate.go @@ -3,6 +3,7 @@ package bgp import ( "encoding/binary" "fmt" + "math" "net" "strconv" ) @@ -139,7 +140,7 @@ func ValidateAttribute(a PathAttributeInterface, rfs map[RouteFamily]BGPAddPathM return false, err } case *PathAttributeOrigin: - v := uint8(p.Value[0]) + v := uint8(p.Value) if v != BGP_ORIGIN_ATTR_TYPE_IGP && v != BGP_ORIGIN_ATTR_TYPE_EGP && v != BGP_ORIGIN_ATTR_TYPE_INCOMPLETE { @@ -226,14 +227,14 @@ func ValidateAttribute(a PathAttributeInterface, rfs map[RouteFamily]BGPAddPathM } // validator for PathAttribute -func ValidateFlags(t BGPAttrType, flags BGPAttrFlag) (bool, string) { +func validatePathAttributeFlags(t BGPAttrType, flags BGPAttrFlag) string { /* * RFC 4271 P.17 For well-known attributes, the Transitive bit MUST be set to 1. */ if flags&BGP_ATTR_FLAG_OPTIONAL == 0 && flags&BGP_ATTR_FLAG_TRANSITIVE == 0 { eMsg := fmt.Sprintf("well-known attribute %s must have transitive flag 1", t) - return false, eMsg + return eMsg } /* * RFC 4271 P.17 For well-known attributes and for optional non-transitive attributes, @@ -241,21 +242,67 @@ func ValidateFlags(t BGPAttrType, flags BGPAttrFlag) (bool, string) { */ if flags&BGP_ATTR_FLAG_OPTIONAL == 0 && flags&BGP_ATTR_FLAG_PARTIAL != 0 { eMsg := fmt.Sprintf("well-known attribute %s must have partial bit 0", t) - return false, eMsg + return eMsg } if flags&BGP_ATTR_FLAG_OPTIONAL != 0 && flags&BGP_ATTR_FLAG_TRANSITIVE == 0 && flags&BGP_ATTR_FLAG_PARTIAL != 0 { eMsg := fmt.Sprintf("optional non-transitive attribute %s must have partial bit 0", t) - return false, eMsg + return eMsg } // check flags are correct if f, ok := PathAttrFlags[t]; ok { if f != flags & ^BGP_ATTR_FLAG_EXTENDED_LENGTH & ^BGP_ATTR_FLAG_PARTIAL { eMsg := fmt.Sprintf("flags are invalid. attribute type: %s, expect: %s, actual: %s", t, f, flags) - return false, eMsg + return eMsg } } - return true, "" + return "" +} + +func validateAsPathValueBytes(data []byte) (bool, error) { + eCode := uint8(BGP_ERROR_UPDATE_MESSAGE_ERROR) + eSubCode := uint8(BGP_ERROR_SUB_MALFORMED_AS_PATH) + if len(data)%2 != 0 { + return false, NewMessageError(eCode, eSubCode, nil, "AS PATH length is not odd") + } + + tryParse := func(data []byte, use4byte bool) (bool, error) { + for len(data) > 0 { + if len(data) < 2 { + return false, NewMessageError(eCode, eSubCode, nil, "AS PATH header is short") + } + segType := data[0] + if segType == 0 || segType > 4 { + return false, NewMessageError(eCode, eSubCode, nil, "unknown AS_PATH seg type") + } + asNum := data[1] + data = data[2:] + if asNum == 0 || int(asNum) > math.MaxUint8 { + return false, NewMessageError(eCode, eSubCode, nil, "AS PATH the number of AS is incorrect") + } + segLength := int(asNum) + if use4byte == true { + segLength *= 4 + } else { + segLength *= 2 + } + if int(segLength) > len(data) { + return false, NewMessageError(eCode, eSubCode, nil, "seg length is short") + } + data = data[segLength:] + } + return true, nil + } + _, err := tryParse(data, true) + if err == nil { + return true, nil + } + + _, err = tryParse(data, false) + if err == nil { + return false, nil + } + return false, NewMessageError(eCode, eSubCode, nil, "can't parse AS_PATH") } func ValidateBGPMessage(m *BGPMessage) error { |