diff options
Diffstat (limited to 'vendor/github.com/google/gopacket/layers/vrrp.go')
| -rw-r--r-- | vendor/github.com/google/gopacket/layers/vrrp.go | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/vendor/github.com/google/gopacket/layers/vrrp.go b/vendor/github.com/google/gopacket/layers/vrrp.go new file mode 100644 index 0000000..ffaafe6 --- /dev/null +++ b/vendor/github.com/google/gopacket/layers/vrrp.go @@ -0,0 +1,156 @@ +// Copyright 2016 Google, Inc. All rights reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the LICENSE file in the root of the source +// tree. + +package layers + +import ( + "encoding/binary" + "errors" + "net" + + "github.com/google/gopacket" +) + +/* + This layer provides decoding for Virtual Router Redundancy Protocol (VRRP) v2. + https://tools.ietf.org/html/rfc3768#section-5 + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |Version| Type | Virtual Rtr ID| Priority | Count IP Addrs| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Auth Type | Adver Int | Checksum | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | IP Address (1) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | . | + | . | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | IP Address (n) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Authentication Data (1) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Authentication Data (2) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +*/ + +type VRRPv2Type uint8 +type VRRPv2AuthType uint8 + +const ( + VRRPv2Advertisement VRRPv2Type = 0x01 // router advertisement +) + +// String conversions for VRRP message types +func (v VRRPv2Type) String() string { + switch v { + case VRRPv2Advertisement: + return "VRRPv2 Advertisement" + default: + return "" + } +} + +const ( + VRRPv2AuthNoAuth VRRPv2AuthType = 0x00 // No Authentication + VRRPv2AuthReserved1 VRRPv2AuthType = 0x01 // Reserved field 1 + VRRPv2AuthReserved2 VRRPv2AuthType = 0x02 // Reserved field 2 +) + +func (v VRRPv2AuthType) String() string { + switch v { + case VRRPv2AuthNoAuth: + return "No Authentication" + case VRRPv2AuthReserved1: + return "Reserved" + case VRRPv2AuthReserved2: + return "Reserved" + default: + return "" + } +} + +// VRRPv2 represents an VRRP v2 message. +type VRRPv2 struct { + BaseLayer + Version uint8 // The version field specifies the VRRP protocol version of this packet (v2) + Type VRRPv2Type // The type field specifies the type of this VRRP packet. The only type defined in v2 is ADVERTISEMENT + VirtualRtrID uint8 // identifies the virtual router this packet is reporting status for + Priority uint8 // specifies the sending VRRP router's priority for the virtual router (100 = default) + CountIPAddr uint8 // The number of IP addresses contained in this VRRP advertisement. + AuthType VRRPv2AuthType // identifies the authentication method being utilized + AdverInt uint8 // The Advertisement interval indicates the time interval (in seconds) between ADVERTISEMENTS. The default is 1 second + Checksum uint16 // used to detect data corruption in the VRRP message. + IPAddress []net.IP // one or more IP addresses associated with the virtual router. Specified in the CountIPAddr field. +} + +// LayerType returns LayerTypeVRRP for VRRP v2 message. +func (v *VRRPv2) LayerType() gopacket.LayerType { return LayerTypeVRRP } + +func (v *VRRPv2) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error { + + v.BaseLayer = BaseLayer{Contents: data[:len(data)]} + v.Version = data[0] >> 4 // high nibble == VRRP version. We're expecting v2 + + v.Type = VRRPv2Type(data[0] & 0x0F) // low nibble == VRRP type. Expecting 1 (advertisement) + if v.Type != 1 { + // rfc3768: A packet with unknown type MUST be discarded. + return errors.New("Unrecognized VRRPv2 type field.") + } + + v.VirtualRtrID = data[1] + v.Priority = data[2] + + v.CountIPAddr = data[3] + if v.CountIPAddr < 1 { + return errors.New("VRRPv2 number of IP addresses is not valid.") + } + + v.AuthType = VRRPv2AuthType(data[4]) + v.AdverInt = uint8(data[5]) + v.Checksum = binary.BigEndian.Uint16(data[6:8]) + + // populate the IPAddress field. The number of addresses is specified in the v.CountIPAddr field + // offset references the starting byte containing the list of ip addresses + offset := 8 + for i := uint8(0); i < v.CountIPAddr; i++ { + v.IPAddress = append(v.IPAddress, data[offset:offset+4]) + offset += 4 + } + + // any trailing packets here may be authentication data and *should* be ignored in v2 as per RFC + // + // 5.3.10. Authentication Data + // + // The authentication string is currently only used to maintain + // backwards compatibility with RFC 2338. It SHOULD be set to zero on + // transmission and ignored on reception. + return nil +} + +// CanDecode specifies the layer type in which we are attempting to unwrap. +func (v *VRRPv2) CanDecode() gopacket.LayerClass { + return LayerTypeVRRP +} + +// NextLayerType specifies the next layer that should be decoded. VRRP does not contain any further payload, so we set to 0 +func (v *VRRPv2) NextLayerType() gopacket.LayerType { + return gopacket.LayerTypeZero +} + +// The VRRP packet does not include payload data. Setting byte slice to nil +func (v *VRRPv2) Payload() []byte { + return nil +} + +// decodeVRRP will parse VRRP v2 +func decodeVRRP(data []byte, p gopacket.PacketBuilder) error { + if len(data) < 8 { + return errors.New("Not a valid VRRP packet. Packet length is too small.") + } + v := &VRRPv2{} + return decodingLayerDecoder(v, data, p) +} |