716 lines
21 KiB
Go
716 lines
21 KiB
Go
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// Copyright 2017 Google, Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree.
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package layers
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"github.com/google/gopacket"
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)
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// OSPFType denotes what kind of OSPF type it is
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type OSPFType uint8
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// Potential values for OSPF.Type.
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const (
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OSPFHello OSPFType = 1
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OSPFDatabaseDescription OSPFType = 2
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OSPFLinkStateRequest OSPFType = 3
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OSPFLinkStateUpdate OSPFType = 4
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OSPFLinkStateAcknowledgment OSPFType = 5
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)
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// LSA Function Codes for LSAheader.LSType
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const (
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RouterLSAtypeV2 = 0x1
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RouterLSAtype = 0x2001
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NetworkLSAtypeV2 = 0x2
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NetworkLSAtype = 0x2002
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SummaryLSANetworktypeV2 = 0x3
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InterAreaPrefixLSAtype = 0x2003
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SummaryLSAASBRtypeV2 = 0x4
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InterAreaRouterLSAtype = 0x2004
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ASExternalLSAtypeV2 = 0x5
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ASExternalLSAtype = 0x4005
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NSSALSAtype = 0x2007
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NSSALSAtypeV2 = 0x7
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LinkLSAtype = 0x0008
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IntraAreaPrefixLSAtype = 0x2009
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)
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// String conversions for OSPFType
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func (i OSPFType) String() string {
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switch i {
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case OSPFHello:
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return "Hello"
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case OSPFDatabaseDescription:
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return "Database Description"
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case OSPFLinkStateRequest:
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return "Link State Request"
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case OSPFLinkStateUpdate:
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return "Link State Update"
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case OSPFLinkStateAcknowledgment:
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return "Link State Acknowledgment"
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default:
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return ""
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}
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}
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// Prefix extends IntraAreaPrefixLSA
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type Prefix struct {
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PrefixLength uint8
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PrefixOptions uint8
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Metric uint16
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AddressPrefix []byte
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}
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// IntraAreaPrefixLSA is the struct from RFC 5340 A.4.10.
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type IntraAreaPrefixLSA struct {
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NumOfPrefixes uint16
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RefLSType uint16
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RefLinkStateID uint32
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RefAdvRouter uint32
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Prefixes []Prefix
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}
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// LinkLSA is the struct from RFC 5340 A.4.9.
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type LinkLSA struct {
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RtrPriority uint8
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Options uint32
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LinkLocalAddress []byte
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NumOfPrefixes uint32
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Prefixes []Prefix
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}
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// ASExternalLSAV2 is the struct from RFC 2328 A.4.5.
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type ASExternalLSAV2 struct {
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NetworkMask uint32
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ExternalBit uint8
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Metric uint32
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ForwardingAddress uint32
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ExternalRouteTag uint32
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}
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// ASExternalLSA is the struct from RFC 5340 A.4.7.
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type ASExternalLSA struct {
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Flags uint8
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Metric uint32
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PrefixLength uint8
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PrefixOptions uint8
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RefLSType uint16
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AddressPrefix []byte
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ForwardingAddress []byte
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ExternalRouteTag uint32
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RefLinkStateID uint32
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}
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// InterAreaRouterLSA is the struct from RFC 5340 A.4.6.
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type InterAreaRouterLSA struct {
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Options uint32
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Metric uint32
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DestinationRouterID uint32
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}
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// InterAreaPrefixLSA is the struct from RFC 5340 A.4.5.
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type InterAreaPrefixLSA struct {
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Metric uint32
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PrefixLength uint8
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PrefixOptions uint8
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AddressPrefix []byte
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}
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// NetworkLSA is the struct from RFC 5340 A.4.4.
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type NetworkLSA struct {
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Options uint32
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AttachedRouter []uint32
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}
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// NetworkLSAV2 is the struct from RFC 2328 A.4.3.
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type NetworkLSAV2 struct {
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NetworkMask uint32
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AttachedRouter []uint32
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}
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// RouterV2 extends RouterLSAV2
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type RouterV2 struct {
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Type uint8
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LinkID uint32
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LinkData uint32
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Metric uint16
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}
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// RouterLSAV2 is the struct from RFC 2328 A.4.2.
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type RouterLSAV2 struct {
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Flags uint8
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Links uint16
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Routers []RouterV2
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}
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// Router extends RouterLSA
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type Router struct {
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Type uint8
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Metric uint16
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InterfaceID uint32
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NeighborInterfaceID uint32
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NeighborRouterID uint32
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}
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// RouterLSA is the struct from RFC 5340 A.4.3.
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type RouterLSA struct {
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Flags uint8
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Options uint32
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Routers []Router
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}
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// LSAheader is the struct from RFC 5340 A.4.2 and RFC 2328 A.4.1.
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type LSAheader struct {
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LSAge uint16
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LSType uint16
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LinkStateID uint32
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AdvRouter uint32
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LSSeqNumber uint32
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LSChecksum uint16
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Length uint16
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LSOptions uint8
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}
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// LSA links LSAheader with the structs from RFC 5340 A.4.
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type LSA struct {
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LSAheader
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Content interface{}
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}
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// LSUpdate is the struct from RFC 5340 A.3.5.
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type LSUpdate struct {
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NumOfLSAs uint32
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LSAs []LSA
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}
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// LSReq is the struct from RFC 5340 A.3.4.
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type LSReq struct {
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LSType uint16
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LSID uint32
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AdvRouter uint32
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}
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// DbDescPkg is the struct from RFC 5340 A.3.3.
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type DbDescPkg struct {
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Options uint32
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InterfaceMTU uint16
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Flags uint16
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DDSeqNumber uint32
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LSAinfo []LSAheader
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}
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// HelloPkg is the struct from RFC 5340 A.3.2.
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type HelloPkg struct {
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InterfaceID uint32
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RtrPriority uint8
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Options uint32
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HelloInterval uint16
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RouterDeadInterval uint32
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DesignatedRouterID uint32
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BackupDesignatedRouterID uint32
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NeighborID []uint32
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}
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// HelloPkgV2 extends the HelloPkg struct with OSPFv2 information
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type HelloPkgV2 struct {
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HelloPkg
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NetworkMask uint32
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}
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// OSPF is a basic OSPF packet header with common fields of Version 2 and Version 3.
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type OSPF struct {
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Version uint8
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Type OSPFType
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PacketLength uint16
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RouterID uint32
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AreaID uint32
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Checksum uint16
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Content interface{}
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}
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//OSPFv2 extend the OSPF head with version 2 specific fields
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type OSPFv2 struct {
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BaseLayer
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OSPF
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AuType uint16
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Authentication uint64
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}
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// OSPFv3 extend the OSPF head with version 3 specific fields
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type OSPFv3 struct {
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BaseLayer
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OSPF
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Instance uint8
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Reserved uint8
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}
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// getLSAsv2 parses the LSA information from the packet for OSPFv2
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func getLSAsv2(num uint32, data []byte) ([]LSA, error) {
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var lsas []LSA
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var i uint32 = 0
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var offset uint32 = 0
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for ; i < num; i++ {
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lstype := uint16(data[offset+3])
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lsalength := binary.BigEndian.Uint16(data[offset+18 : offset+20])
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content, err := extractLSAInformation(lstype, lsalength, data[offset:])
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if err != nil {
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return nil, fmt.Errorf("Could not extract Link State type.")
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}
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lsa := LSA{
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LSAheader: LSAheader{
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LSAge: binary.BigEndian.Uint16(data[offset : offset+2]),
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LSOptions: data[offset+2],
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LSType: lstype,
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LinkStateID: binary.BigEndian.Uint32(data[offset+4 : offset+8]),
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AdvRouter: binary.BigEndian.Uint32(data[offset+8 : offset+12]),
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LSSeqNumber: binary.BigEndian.Uint32(data[offset+12 : offset+16]),
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LSChecksum: binary.BigEndian.Uint16(data[offset+16 : offset+18]),
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Length: lsalength,
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},
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Content: content,
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}
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lsas = append(lsas, lsa)
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offset += uint32(lsalength)
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}
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return lsas, nil
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}
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// extractLSAInformation extracts all the LSA information
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func extractLSAInformation(lstype, lsalength uint16, data []byte) (interface{}, error) {
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if lsalength < 20 {
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return nil, fmt.Errorf("Link State header length %v too short, %v required", lsalength, 20)
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}
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if len(data) < int(lsalength) {
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return nil, fmt.Errorf("Link State header length %v too short, %v required", len(data), lsalength)
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}
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var content interface{}
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switch lstype {
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case RouterLSAtypeV2:
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var routers []RouterV2
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var j uint32
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for j = 24; j < uint32(lsalength); j += 12 {
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if len(data) < int(j+12) {
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return nil, errors.New("LSAtypeV2 too small")
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}
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router := RouterV2{
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LinkID: binary.BigEndian.Uint32(data[j : j+4]),
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LinkData: binary.BigEndian.Uint32(data[j+4 : j+8]),
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Type: uint8(data[j+8]),
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Metric: binary.BigEndian.Uint16(data[j+10 : j+12]),
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}
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routers = append(routers, router)
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}
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if len(data) < 24 {
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return nil, errors.New("LSAtypeV2 too small")
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}
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links := binary.BigEndian.Uint16(data[22:24])
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content = RouterLSAV2{
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Flags: data[20],
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Links: links,
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Routers: routers,
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}
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case NSSALSAtypeV2:
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fallthrough
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case ASExternalLSAtypeV2:
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content = ASExternalLSAV2{
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NetworkMask: binary.BigEndian.Uint32(data[20:24]),
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ExternalBit: data[24] & 0x80,
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Metric: binary.BigEndian.Uint32(data[24:28]) & 0x00FFFFFF,
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ForwardingAddress: binary.BigEndian.Uint32(data[28:32]),
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ExternalRouteTag: binary.BigEndian.Uint32(data[32:36]),
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}
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case NetworkLSAtypeV2:
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var routers []uint32
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var j uint32
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for j = 24; j < uint32(lsalength); j += 4 {
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routers = append(routers, binary.BigEndian.Uint32(data[j:j+4]))
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}
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content = NetworkLSAV2{
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NetworkMask: binary.BigEndian.Uint32(data[20:24]),
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AttachedRouter: routers,
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}
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case RouterLSAtype:
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var routers []Router
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var j uint32
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for j = 24; j < uint32(lsalength); j += 16 {
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router := Router{
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Type: uint8(data[j]),
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Metric: binary.BigEndian.Uint16(data[j+2 : j+4]),
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InterfaceID: binary.BigEndian.Uint32(data[j+4 : j+8]),
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NeighborInterfaceID: binary.BigEndian.Uint32(data[j+8 : j+12]),
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NeighborRouterID: binary.BigEndian.Uint32(data[j+12 : j+16]),
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}
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routers = append(routers, router)
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}
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content = RouterLSA{
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Flags: uint8(data[20]),
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Options: binary.BigEndian.Uint32(data[20:24]) & 0x00FFFFFF,
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Routers: routers,
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}
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case NetworkLSAtype:
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var routers []uint32
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var j uint32
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for j = 24; j < uint32(lsalength); j += 4 {
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routers = append(routers, binary.BigEndian.Uint32(data[j:j+4]))
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}
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content = NetworkLSA{
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Options: binary.BigEndian.Uint32(data[20:24]) & 0x00FFFFFF,
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AttachedRouter: routers,
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}
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case InterAreaPrefixLSAtype:
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content = InterAreaPrefixLSA{
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Metric: binary.BigEndian.Uint32(data[20:24]) & 0x00FFFFFF,
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PrefixLength: uint8(data[24]),
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PrefixOptions: uint8(data[25]),
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AddressPrefix: data[28:uint32(lsalength)],
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}
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case InterAreaRouterLSAtype:
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content = InterAreaRouterLSA{
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Options: binary.BigEndian.Uint32(data[20:24]) & 0x00FFFFFF,
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Metric: binary.BigEndian.Uint32(data[24:28]) & 0x00FFFFFF,
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DestinationRouterID: binary.BigEndian.Uint32(data[28:32]),
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}
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case ASExternalLSAtype:
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fallthrough
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case NSSALSAtype:
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flags := uint8(data[20])
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prefixLen := uint8(data[24]) / 8
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|
var forwardingAddress []byte
|
||
|
|
if (flags & 0x02) == 0x02 {
|
||
|
|
forwardingAddress = data[28+uint32(prefixLen) : 28+uint32(prefixLen)+16]
|
||
|
|
}
|
||
|
|
content = ASExternalLSA{
|
||
|
|
Flags: flags,
|
||
|
|
Metric: binary.BigEndian.Uint32(data[20:24]) & 0x00FFFFFF,
|
||
|
|
PrefixLength: prefixLen,
|
||
|
|
PrefixOptions: uint8(data[25]),
|
||
|
|
RefLSType: binary.BigEndian.Uint16(data[26:28]),
|
||
|
|
AddressPrefix: data[28 : 28+uint32(prefixLen)],
|
||
|
|
ForwardingAddress: forwardingAddress,
|
||
|
|
}
|
||
|
|
case LinkLSAtype:
|
||
|
|
var prefixes []Prefix
|
||
|
|
var prefixOffset uint32 = 44
|
||
|
|
var j uint32
|
||
|
|
numOfPrefixes := binary.BigEndian.Uint32(data[40:44])
|
||
|
|
for j = 0; j < numOfPrefixes; j++ {
|
||
|
|
prefixLen := uint8(data[prefixOffset])
|
||
|
|
prefix := Prefix{
|
||
|
|
PrefixLength: prefixLen,
|
||
|
|
PrefixOptions: uint8(data[prefixOffset+1]),
|
||
|
|
AddressPrefix: data[prefixOffset+4 : prefixOffset+4+uint32(prefixLen)/8],
|
||
|
|
}
|
||
|
|
prefixes = append(prefixes, prefix)
|
||
|
|
prefixOffset = prefixOffset + 4 + uint32(prefixLen)/8
|
||
|
|
}
|
||
|
|
content = LinkLSA{
|
||
|
|
RtrPriority: uint8(data[20]),
|
||
|
|
Options: binary.BigEndian.Uint32(data[20:24]) & 0x00FFFFFF,
|
||
|
|
LinkLocalAddress: data[24:40],
|
||
|
|
NumOfPrefixes: numOfPrefixes,
|
||
|
|
Prefixes: prefixes,
|
||
|
|
}
|
||
|
|
case IntraAreaPrefixLSAtype:
|
||
|
|
var prefixes []Prefix
|
||
|
|
var prefixOffset uint32 = 32
|
||
|
|
var j uint16
|
||
|
|
numOfPrefixes := binary.BigEndian.Uint16(data[20:22])
|
||
|
|
for j = 0; j < numOfPrefixes; j++ {
|
||
|
|
prefixLen := uint8(data[prefixOffset])
|
||
|
|
prefix := Prefix{
|
||
|
|
PrefixLength: prefixLen,
|
||
|
|
PrefixOptions: uint8(data[prefixOffset+1]),
|
||
|
|
Metric: binary.BigEndian.Uint16(data[prefixOffset+2 : prefixOffset+4]),
|
||
|
|
AddressPrefix: data[prefixOffset+4 : prefixOffset+4+uint32(prefixLen)/8],
|
||
|
|
}
|
||
|
|
prefixes = append(prefixes, prefix)
|
||
|
|
prefixOffset = prefixOffset + 4 + uint32(prefixLen)
|
||
|
|
}
|
||
|
|
content = IntraAreaPrefixLSA{
|
||
|
|
NumOfPrefixes: numOfPrefixes,
|
||
|
|
RefLSType: binary.BigEndian.Uint16(data[22:24]),
|
||
|
|
RefLinkStateID: binary.BigEndian.Uint32(data[24:28]),
|
||
|
|
RefAdvRouter: binary.BigEndian.Uint32(data[28:32]),
|
||
|
|
Prefixes: prefixes,
|
||
|
|
}
|
||
|
|
default:
|
||
|
|
return nil, fmt.Errorf("Unknown Link State type.")
|
||
|
|
}
|
||
|
|
return content, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// getLSAs parses the LSA information from the packet for OSPFv3
|
||
|
|
func getLSAs(num uint32, data []byte) ([]LSA, error) {
|
||
|
|
var lsas []LSA
|
||
|
|
var i uint32 = 0
|
||
|
|
var offset uint32 = 0
|
||
|
|
for ; i < num; i++ {
|
||
|
|
var content interface{}
|
||
|
|
lstype := binary.BigEndian.Uint16(data[offset+2 : offset+4])
|
||
|
|
lsalength := binary.BigEndian.Uint16(data[offset+18 : offset+20])
|
||
|
|
|
||
|
|
content, err := extractLSAInformation(lstype, lsalength, data[offset:])
|
||
|
|
if err != nil {
|
||
|
|
return nil, fmt.Errorf("Could not extract Link State type.")
|
||
|
|
}
|
||
|
|
lsa := LSA{
|
||
|
|
LSAheader: LSAheader{
|
||
|
|
LSAge: binary.BigEndian.Uint16(data[offset : offset+2]),
|
||
|
|
LSType: lstype,
|
||
|
|
LinkStateID: binary.BigEndian.Uint32(data[offset+4 : offset+8]),
|
||
|
|
AdvRouter: binary.BigEndian.Uint32(data[offset+8 : offset+12]),
|
||
|
|
LSSeqNumber: binary.BigEndian.Uint32(data[offset+12 : offset+16]),
|
||
|
|
LSChecksum: binary.BigEndian.Uint16(data[offset+16 : offset+18]),
|
||
|
|
Length: lsalength,
|
||
|
|
},
|
||
|
|
Content: content,
|
||
|
|
}
|
||
|
|
lsas = append(lsas, lsa)
|
||
|
|
offset += uint32(lsalength)
|
||
|
|
}
|
||
|
|
return lsas, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// DecodeFromBytes decodes the given bytes into the OSPF layer.
|
||
|
|
func (ospf *OSPFv2) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
|
||
|
|
if len(data) < 24 {
|
||
|
|
return fmt.Errorf("Packet too smal for OSPF Version 2")
|
||
|
|
}
|
||
|
|
|
||
|
|
ospf.Version = uint8(data[0])
|
||
|
|
ospf.Type = OSPFType(data[1])
|
||
|
|
ospf.PacketLength = binary.BigEndian.Uint16(data[2:4])
|
||
|
|
ospf.RouterID = binary.BigEndian.Uint32(data[4:8])
|
||
|
|
ospf.AreaID = binary.BigEndian.Uint32(data[8:12])
|
||
|
|
ospf.Checksum = binary.BigEndian.Uint16(data[12:14])
|
||
|
|
ospf.AuType = binary.BigEndian.Uint16(data[14:16])
|
||
|
|
ospf.Authentication = binary.BigEndian.Uint64(data[16:24])
|
||
|
|
|
||
|
|
switch ospf.Type {
|
||
|
|
case OSPFHello:
|
||
|
|
var neighbors []uint32
|
||
|
|
for i := 44; uint16(i+4) <= ospf.PacketLength; i += 4 {
|
||
|
|
neighbors = append(neighbors, binary.BigEndian.Uint32(data[i:i+4]))
|
||
|
|
}
|
||
|
|
ospf.Content = HelloPkgV2{
|
||
|
|
NetworkMask: binary.BigEndian.Uint32(data[24:28]),
|
||
|
|
HelloPkg: HelloPkg{
|
||
|
|
HelloInterval: binary.BigEndian.Uint16(data[28:30]),
|
||
|
|
Options: uint32(data[30]),
|
||
|
|
RtrPriority: uint8(data[31]),
|
||
|
|
RouterDeadInterval: binary.BigEndian.Uint32(data[32:36]),
|
||
|
|
DesignatedRouterID: binary.BigEndian.Uint32(data[36:40]),
|
||
|
|
BackupDesignatedRouterID: binary.BigEndian.Uint32(data[40:44]),
|
||
|
|
NeighborID: neighbors,
|
||
|
|
},
|
||
|
|
}
|
||
|
|
case OSPFDatabaseDescription:
|
||
|
|
var lsas []LSAheader
|
||
|
|
for i := 32; uint16(i+20) <= ospf.PacketLength; i += 20 {
|
||
|
|
lsa := LSAheader{
|
||
|
|
LSAge: binary.BigEndian.Uint16(data[i : i+2]),
|
||
|
|
LSType: binary.BigEndian.Uint16(data[i+2 : i+4]),
|
||
|
|
LinkStateID: binary.BigEndian.Uint32(data[i+4 : i+8]),
|
||
|
|
AdvRouter: binary.BigEndian.Uint32(data[i+8 : i+12]),
|
||
|
|
LSSeqNumber: binary.BigEndian.Uint32(data[i+12 : i+16]),
|
||
|
|
LSChecksum: binary.BigEndian.Uint16(data[i+16 : i+18]),
|
||
|
|
Length: binary.BigEndian.Uint16(data[i+18 : i+20]),
|
||
|
|
}
|
||
|
|
lsas = append(lsas, lsa)
|
||
|
|
}
|
||
|
|
ospf.Content = DbDescPkg{
|
||
|
|
InterfaceMTU: binary.BigEndian.Uint16(data[24:26]),
|
||
|
|
Options: uint32(data[26]),
|
||
|
|
Flags: uint16(data[27]),
|
||
|
|
DDSeqNumber: binary.BigEndian.Uint32(data[28:32]),
|
||
|
|
LSAinfo: lsas,
|
||
|
|
}
|
||
|
|
case OSPFLinkStateRequest:
|
||
|
|
var lsrs []LSReq
|
||
|
|
for i := 24; uint16(i+12) <= ospf.PacketLength; i += 12 {
|
||
|
|
lsr := LSReq{
|
||
|
|
LSType: binary.BigEndian.Uint16(data[i+2 : i+4]),
|
||
|
|
LSID: binary.BigEndian.Uint32(data[i+4 : i+8]),
|
||
|
|
AdvRouter: binary.BigEndian.Uint32(data[i+8 : i+12]),
|
||
|
|
}
|
||
|
|
lsrs = append(lsrs, lsr)
|
||
|
|
}
|
||
|
|
ospf.Content = lsrs
|
||
|
|
case OSPFLinkStateUpdate:
|
||
|
|
num := binary.BigEndian.Uint32(data[24:28])
|
||
|
|
|
||
|
|
lsas, err := getLSAsv2(num, data[28:])
|
||
|
|
if err != nil {
|
||
|
|
return fmt.Errorf("Cannot parse Link State Update packet: %v", err)
|
||
|
|
}
|
||
|
|
ospf.Content = LSUpdate{
|
||
|
|
NumOfLSAs: num,
|
||
|
|
LSAs: lsas,
|
||
|
|
}
|
||
|
|
case OSPFLinkStateAcknowledgment:
|
||
|
|
var lsas []LSAheader
|
||
|
|
for i := 24; uint16(i+20) <= ospf.PacketLength; i += 20 {
|
||
|
|
lsa := LSAheader{
|
||
|
|
LSAge: binary.BigEndian.Uint16(data[i : i+2]),
|
||
|
|
LSOptions: data[i+2],
|
||
|
|
LSType: uint16(data[i+3]),
|
||
|
|
LinkStateID: binary.BigEndian.Uint32(data[i+4 : i+8]),
|
||
|
|
AdvRouter: binary.BigEndian.Uint32(data[i+8 : i+12]),
|
||
|
|
LSSeqNumber: binary.BigEndian.Uint32(data[i+12 : i+16]),
|
||
|
|
LSChecksum: binary.BigEndian.Uint16(data[i+16 : i+18]),
|
||
|
|
Length: binary.BigEndian.Uint16(data[i+18 : i+20]),
|
||
|
|
}
|
||
|
|
lsas = append(lsas, lsa)
|
||
|
|
}
|
||
|
|
ospf.Content = lsas
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// DecodeFromBytes decodes the given bytes into the OSPF layer.
|
||
|
|
func (ospf *OSPFv3) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
|
||
|
|
|
||
|
|
if len(data) < 16 {
|
||
|
|
return fmt.Errorf("Packet too smal for OSPF Version 3")
|
||
|
|
}
|
||
|
|
|
||
|
|
ospf.Version = uint8(data[0])
|
||
|
|
ospf.Type = OSPFType(data[1])
|
||
|
|
ospf.PacketLength = binary.BigEndian.Uint16(data[2:4])
|
||
|
|
ospf.RouterID = binary.BigEndian.Uint32(data[4:8])
|
||
|
|
ospf.AreaID = binary.BigEndian.Uint32(data[8:12])
|
||
|
|
ospf.Checksum = binary.BigEndian.Uint16(data[12:14])
|
||
|
|
ospf.Instance = uint8(data[14])
|
||
|
|
ospf.Reserved = uint8(data[15])
|
||
|
|
|
||
|
|
switch ospf.Type {
|
||
|
|
case OSPFHello:
|
||
|
|
var neighbors []uint32
|
||
|
|
for i := 36; uint16(i+4) <= ospf.PacketLength; i += 4 {
|
||
|
|
neighbors = append(neighbors, binary.BigEndian.Uint32(data[i:i+4]))
|
||
|
|
}
|
||
|
|
ospf.Content = HelloPkg{
|
||
|
|
InterfaceID: binary.BigEndian.Uint32(data[16:20]),
|
||
|
|
RtrPriority: uint8(data[20]),
|
||
|
|
Options: binary.BigEndian.Uint32(data[21:25]) >> 8,
|
||
|
|
HelloInterval: binary.BigEndian.Uint16(data[24:26]),
|
||
|
|
RouterDeadInterval: uint32(binary.BigEndian.Uint16(data[26:28])),
|
||
|
|
DesignatedRouterID: binary.BigEndian.Uint32(data[28:32]),
|
||
|
|
BackupDesignatedRouterID: binary.BigEndian.Uint32(data[32:36]),
|
||
|
|
NeighborID: neighbors,
|
||
|
|
}
|
||
|
|
case OSPFDatabaseDescription:
|
||
|
|
var lsas []LSAheader
|
||
|
|
for i := 28; uint16(i+20) <= ospf.PacketLength; i += 20 {
|
||
|
|
lsa := LSAheader{
|
||
|
|
LSAge: binary.BigEndian.Uint16(data[i : i+2]),
|
||
|
|
LSType: binary.BigEndian.Uint16(data[i+2 : i+4]),
|
||
|
|
LinkStateID: binary.BigEndian.Uint32(data[i+4 : i+8]),
|
||
|
|
AdvRouter: binary.BigEndian.Uint32(data[i+8 : i+12]),
|
||
|
|
LSSeqNumber: binary.BigEndian.Uint32(data[i+12 : i+16]),
|
||
|
|
LSChecksum: binary.BigEndian.Uint16(data[i+16 : i+18]),
|
||
|
|
Length: binary.BigEndian.Uint16(data[i+18 : i+20]),
|
||
|
|
}
|
||
|
|
lsas = append(lsas, lsa)
|
||
|
|
}
|
||
|
|
ospf.Content = DbDescPkg{
|
||
|
|
Options: binary.BigEndian.Uint32(data[16:20]) & 0x00FFFFFF,
|
||
|
|
InterfaceMTU: binary.BigEndian.Uint16(data[20:22]),
|
||
|
|
Flags: binary.BigEndian.Uint16(data[22:24]),
|
||
|
|
DDSeqNumber: binary.BigEndian.Uint32(data[24:28]),
|
||
|
|
LSAinfo: lsas,
|
||
|
|
}
|
||
|
|
case OSPFLinkStateRequest:
|
||
|
|
var lsrs []LSReq
|
||
|
|
for i := 16; uint16(i+12) <= ospf.PacketLength; i += 12 {
|
||
|
|
lsr := LSReq{
|
||
|
|
LSType: binary.BigEndian.Uint16(data[i+2 : i+4]),
|
||
|
|
LSID: binary.BigEndian.Uint32(data[i+4 : i+8]),
|
||
|
|
AdvRouter: binary.BigEndian.Uint32(data[i+8 : i+12]),
|
||
|
|
}
|
||
|
|
lsrs = append(lsrs, lsr)
|
||
|
|
}
|
||
|
|
ospf.Content = lsrs
|
||
|
|
case OSPFLinkStateUpdate:
|
||
|
|
num := binary.BigEndian.Uint32(data[16:20])
|
||
|
|
lsas, err := getLSAs(num, data[20:])
|
||
|
|
if err != nil {
|
||
|
|
return fmt.Errorf("Cannot parse Link State Update packet: %v", err)
|
||
|
|
}
|
||
|
|
ospf.Content = LSUpdate{
|
||
|
|
NumOfLSAs: num,
|
||
|
|
LSAs: lsas,
|
||
|
|
}
|
||
|
|
|
||
|
|
case OSPFLinkStateAcknowledgment:
|
||
|
|
var lsas []LSAheader
|
||
|
|
for i := 16; uint16(i+20) <= ospf.PacketLength; i += 20 {
|
||
|
|
lsa := LSAheader{
|
||
|
|
LSAge: binary.BigEndian.Uint16(data[i : i+2]),
|
||
|
|
LSType: binary.BigEndian.Uint16(data[i+2 : i+4]),
|
||
|
|
LinkStateID: binary.BigEndian.Uint32(data[i+4 : i+8]),
|
||
|
|
AdvRouter: binary.BigEndian.Uint32(data[i+8 : i+12]),
|
||
|
|
LSSeqNumber: binary.BigEndian.Uint32(data[i+12 : i+16]),
|
||
|
|
LSChecksum: binary.BigEndian.Uint16(data[i+16 : i+18]),
|
||
|
|
Length: binary.BigEndian.Uint16(data[i+18 : i+20]),
|
||
|
|
}
|
||
|
|
lsas = append(lsas, lsa)
|
||
|
|
}
|
||
|
|
ospf.Content = lsas
|
||
|
|
default:
|
||
|
|
}
|
||
|
|
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// LayerType returns LayerTypeOSPF
|
||
|
|
func (ospf *OSPFv2) LayerType() gopacket.LayerType {
|
||
|
|
return LayerTypeOSPF
|
||
|
|
}
|
||
|
|
func (ospf *OSPFv3) LayerType() gopacket.LayerType {
|
||
|
|
return LayerTypeOSPF
|
||
|
|
}
|
||
|
|
|
||
|
|
// NextLayerType returns the layer type contained by this DecodingLayer.
|
||
|
|
func (ospf *OSPFv2) NextLayerType() gopacket.LayerType {
|
||
|
|
return gopacket.LayerTypeZero
|
||
|
|
}
|
||
|
|
func (ospf *OSPFv3) NextLayerType() gopacket.LayerType {
|
||
|
|
return gopacket.LayerTypeZero
|
||
|
|
}
|
||
|
|
|
||
|
|
// CanDecode returns the set of layer types that this DecodingLayer can decode.
|
||
|
|
func (ospf *OSPFv2) CanDecode() gopacket.LayerClass {
|
||
|
|
return LayerTypeOSPF
|
||
|
|
}
|
||
|
|
func (ospf *OSPFv3) CanDecode() gopacket.LayerClass {
|
||
|
|
return LayerTypeOSPF
|
||
|
|
}
|
||
|
|
|
||
|
|
func decodeOSPF(data []byte, p gopacket.PacketBuilder) error {
|
||
|
|
if len(data) < 14 {
|
||
|
|
return fmt.Errorf("Packet too smal for OSPF")
|
||
|
|
}
|
||
|
|
|
||
|
|
switch uint8(data[0]) {
|
||
|
|
case 2:
|
||
|
|
ospf := &OSPFv2{}
|
||
|
|
return decodingLayerDecoder(ospf, data, p)
|
||
|
|
case 3:
|
||
|
|
ospf := &OSPFv3{}
|
||
|
|
return decodingLayerDecoder(ospf, data, p)
|
||
|
|
default:
|
||
|
|
}
|
||
|
|
|
||
|
|
return fmt.Errorf("Unable to determine OSPF type.")
|
||
|
|
}
|