Source: ../../ospf/packet.hh
|
|
|
|
// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// vim:set sts=4 ts=8:
// Copyright (c) 2001-2007 International Computer Science Institute
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software")
// to deal in the Software without restriction, subject to the conditions
// listed in the XORP LICENSE file. These conditions include: you must
// preserve this copyright notice, and you cannot mention the copyright
// holders in advertising related to the Software without their permission.
// The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
// notice is a summary of the XORP LICENSE file; the license in that file is
// legally binding.
// $XORP: xorp/ospf/packet.hh,v 1.39 2007/02/16 22:46:41 pavlin Exp $
#ifndef __OSPF_PACKET_HH__
#define __OSPF_PACKET_HH__
/**
* All packet decode routines must inherit from this interface.
* Also provides some utility routines to perform common packet processing.
*/
class Packet {
public:
static const size_t STANDARD_HEADER_V2 = 24;
static const size_t STANDARD_HEADER_V3 = 16;
static const size_t CHECKSUM_OFFSET = 12;
// OSPFv2 only.
static const size_t AUTH_TYPE_OFFSET = 14;
static const size_t AUTH_PAYLOAD_OFFSET = 16;
static const size_t AUTH_PAYLOAD_SIZE = 8;
Packet(OspfTypes::Version version)
: _version(version), _auth_type(0), _instance_id(0)
{
memset(&_auth[0], 0, sizeof(_auth));
}
virtual ~Packet()
{}
/**
* Decode standard header.
*
* Used by the derived classes to extract the standard header and
* options field.
*
* @param len if the frame is larger than what is specified by the
* header length field drop the length down to the header length.
*
* @return the offset where the specific header starts.
*/
size_t decode_standard_header(uint8_t *ptr, size_t& len) throw(InvalidPacket);
/**
* Decode the packet.
* The returned packet must be free'd.
*/
virtual Packet *decode(uint8_t *ptr, size_t len)
const throw(InvalidPacket) = 0;
/**
* Encode standard header.
*
* Used by the derived classes to put the standard header in the
* packet. Which includes the checksum so all other fields should
* already be in the packet.
*
* @param ptr location to start writing header.
* @param len size of the buffer.
* @return The offset that the header has been written to. Returns
* 0 on failure, such as the buffer is too small.
*/
size_t encode_standard_header(uint8_t *ptr, size_t len);
/**
* Encode the packet.
*
* @param pkt vector into which the packet should be placed.
* @return true if the encoding suceeded.
*/
virtual bool encode(vector<uint8_t>& pkt) = 0;
/**
* Store the original packet, required for authentication.
*/
void store(uint8_t *ptr, size_t len) {
_pkt.resize(len);
memcpy(&_pkt[0], ptr, len);
}
/**
* Get a reference to the original packet data, required for
* authentication.
*/
vector<uint8_t>& get() {
return _pkt;
}
/**
* @return The version this packet represents.
*/
OspfTypes::Version get_version() const { return _version; }
/**
* It is the responsibilty of the derived type to return this
* information.
* @return The type this packet represents.
*/
virtual OspfTypes::Type get_type() const = 0;
/**
* Get the Router ID.
*/
OspfTypes::RouterID get_router_id() const { return _router_id; }
/**
* Set the Router ID.
*/
void set_router_id(OspfTypes::RouterID id) { _router_id = id; }
/**
* Get the Area ID.
*/
OspfTypes::AreaID get_area_id() const { return _area_id; }
/**
* Set the Area ID.
*/
void set_area_id(OspfTypes::AreaID id) { _area_id = id; }
/**
* Get the Auth Type.
*/
uint16_t get_auth_type() const { return _auth_type; }
/**
* Set the Auth Type.
*/
void set_auth_type(uint16_t auth_type) { _auth_type = auth_type; }
/**
* Get the Instance ID.
*/
uint8_t get_instance_id() const {
XLOG_ASSERT(OspfTypes::V3 == get_version());
return _instance_id;
}
/**
* Set the Instance ID.
*/
void set_instance_id(uint8_t instance_id) {
XLOG_ASSERT(OspfTypes::V3 == get_version());
_instance_id = instance_id;
}
/**
* @return the standard header length for this version of OSPF.
*/
inline size_t
get_standard_header_length() {
switch(_version) {
case OspfTypes::V2:
return STANDARD_HEADER_V2;
break;
case OspfTypes::V3:
return STANDARD_HEADER_V3;
break;
}
XLOG_UNREACHABLE();
return 0;
}
/**
* Decode Point.
*
* If a packet is being decoded the standard header has already been
* processed. This method returns the offset at which the specific
* data starts.
*
* @return The offset at which a derived class should start decoding.
*/
size_t decode_point() const;
/**
* Generate a printable representation of the standard header.
* Used by the derived classes implementing str().
*/
string standard() const;
/**
* Generate a printable representation of the packet.
*/
virtual string str() const = 0;
private:
const OspfTypes::Version _version;
vector<uint8_t> _pkt; // Raw packet
/**
* Set to true when the standard header fields are set.
*/
bool _valid;
/**
* Standard header.
* Version and Type information are constant so therefore not present.
*/
OspfTypes::RouterID _router_id;
OspfTypes::AreaID _area_id;
OspfTypes::AuType _auth_type; // OSPFv2 Only
uint8_t _auth[AUTH_PAYLOAD_SIZE]; // OSPFv2 Only
uint8_t _instance_id; // OSPFv3 Only
};
/**
* Packet byte streams are decoded through this class.
*/
class PacketDecoder {
public:
~PacketDecoder();
/**
* Register the packet/decode routines
*
* @param packet decoder
*/
void register_decoder(Packet *packet);
#if 0
/**
* Register the packet/decode routines
*
* @param packet decoder
* @param version OSPF version of the decoder
* @param type of decoder
*/
void register_decoder(Packet *packet,
OspfTypes::Version version,
OspfTypes::Type type);
#endif
/**
* Decode byte stream.
*
* @param ptr to data packet
* @param length of data packet
*
* @return a packet structure, which must be free'd
*/
Packet *decode(uint8_t *ptr, size_t len) throw(InvalidPacket);
private:
map<OspfTypes::Type , Packet *> _ospfv2; // OSPFv2 Packet decoders
map<OspfTypes::Type , Packet *> _ospfv3; // OSPFv3 Packet decoders
};
/**
* Hello packet
*/
class HelloPacket : public Packet {
public:
static const size_t MINIMUM_LENGTH = 20; // The minumum length
// of a hello packet.
// The same for OSPFv2
// and OSPFv3. How did
// that happen?
HelloPacket(OspfTypes::Version version)
: Packet(version), _network_mask(0), _interface_id(0),
_hello_interval(0), _options(0), _router_priority(0),
_router_dead_interval(0)
{}
OspfTypes::Type get_type() const { return 1; }
Packet *decode(uint8_t *ptr, size_t len) const throw(InvalidPacket);
/**
* Encode the packet.
*
* @param pkt vector into which the packet should be placed.
* @return true if the encoding succeeded.
*/
bool encode(vector<uint8_t>& pkt);
// Network Mask.
void set_network_mask(uint32_t network_mask) {
XLOG_ASSERT(OspfTypes::V2 == get_version());
_network_mask = network_mask;
}
uint32_t get_network_mask() const {
XLOG_ASSERT(OspfTypes::V2 == get_version());
return _network_mask;
}
// Interface ID.
void set_interface_id(uint32_t interface_id) {
XLOG_ASSERT(OspfTypes::V3 == get_version());
_interface_id = interface_id;
}
uint32_t get_interface_id() const {
XLOG_ASSERT(OspfTypes::V3 == get_version());
return _interface_id;
}
// Hello Interval.
void set_hello_interval(uint16_t hello_interval) {
_hello_interval = hello_interval;
}
uint16_t get_hello_interval() const {
return _hello_interval;
}
// Options.
void set_options(uint32_t options) {
switch(get_version()) {
case OspfTypes::V2:
if (options > 0xff)
XLOG_WARNING("Attempt to set %#x in an 8 bit field",
options);
_options = options & 0xff;
break;
case OspfTypes::V3:
if (options > 0xffffff)
XLOG_WARNING("Attempt to set %#x in a 24 bit field",
options);
_options = options & 0xffffff;
break;
}
}
uint32_t get_options() const {
return _options;
}
// Router Priority.
void set_router_priority(uint8_t router_priority) {
_router_priority = router_priority;
}
uint8_t get_router_priority() const {
return _router_priority;
}
// Router Dead Interval.
void set_router_dead_interval(uint32_t router_dead_interval) {
switch(get_version()) {
case OspfTypes::V2:
_router_dead_interval = router_dead_interval;
break;
case OspfTypes::V3:
if ( router_dead_interval > 0xffff)
XLOG_WARNING("Attempt to set %#x in a 16 bit field",
router_dead_interval);
_router_dead_interval = router_dead_interval & 0xffff;
break;
}
}
uint32_t get_router_dead_interval() const {
return _router_dead_interval;
}
// Designated Router
void set_designated_router(OspfTypes::RouterID dr) {
_dr = dr;
}
OspfTypes::RouterID get_designated_router() const {
return _dr;
}
// Backup Designated Router
void set_backup_designated_router(OspfTypes::RouterID bdr) {
_bdr = bdr;
}
OspfTypes::RouterID get_backup_designated_router() const {
return _bdr;
}
list<OspfTypes::RouterID>& get_neighbours() {
return _neighbours;
}
/**
* Generate a printable representation of the packet.
*/
string str() const;
private:
uint32_t _network_mask; // OSPF V2 Only
uint32_t _interface_id; // OSPF V3 Only
uint16_t _hello_interval;
uint32_t _options; // Large enough to accomodate V2 and V3 options
uint8_t _router_priority; // Router Priority.
uint32_t _router_dead_interval; // In seconds.
OspfTypes::RouterID _dr; // Designated router.
OspfTypes::RouterID _bdr; // Backup Designated router.
list<OspfTypes::RouterID> _neighbours; // Router IDs of neighbours.
};
/**
* Database Description Packet
*/
class DataDescriptionPacket : public Packet {
public:
DataDescriptionPacket(OspfTypes::Version version)
: Packet(version), _interface_mtu(0), _options(0),
_i_bit(false), _m_bit(false), _ms_bit(false), _DD_seqno(0)
{}
OspfTypes::Type get_type() const { return 2; }
size_t minimum_length() const {
switch(get_version()) {
case OspfTypes::V2:
return 8;
break;
case OspfTypes::V3:
return 12;
break;
}
XLOG_UNREACHABLE();
return 0;
}
Packet *decode(uint8_t *ptr, size_t len) const throw(InvalidPacket);
/**
* Encode the packet.
*
* @param pkt vector into which the packet should be placed.
* @return true if the encoding suceeded.
*/
bool encode(vector<uint8_t>& pkt);
// Interface MTU
void set_interface_mtu(uint16_t mtu) {
_interface_mtu = mtu;
}
uint16_t get_interface_mtu() const {
return _interface_mtu;
}
// Options.
void set_options(uint32_t options) {
switch(get_version()) {
case OspfTypes::V2:
if (options > 0xff)
XLOG_WARNING("Attempt to set %#x in an 8 bit field",
options);
_options = options & 0xff;
break;
case OspfTypes::V3:
if (options > 0xffffff)
XLOG_WARNING("Attempt to set %#x in a 24 bit field",
options);
_options = options & 0xffffff;
break;
}
}
uint32_t get_options() const {
return _options;
}
// Init bit.
void set_i_bit(bool bit) {
_i_bit = bit;
}
bool get_i_bit() const {
return _i_bit;
}
// More bit.
void set_m_bit(bool bit) {
_m_bit = bit;
}
bool get_m_bit() const {
return _m_bit;
}
// Master/Slave bit
void set_ms_bit(bool bit) {
_ms_bit = bit;
}
bool get_ms_bit() const {
return _ms_bit;
}
// Database description sequence number.
void set_dd_seqno(uint32_t seqno) {
_DD_seqno = seqno;
}
uint32_t get_dd_seqno() const {
return _DD_seqno;
}
list<Lsa_header>& get_lsa_headers() {
return _lsa_headers;
}
/**
* Generate a printable representation of the packet.
*/
string str() const;
private:
uint16_t _interface_mtu;
uint32_t _options; // Large enough to accomodate V2 and V3 options
bool _i_bit; // The init bit.
bool _m_bit; // The more bit.
bool _ms_bit; // The Master/Slave bit.
uint32_t _DD_seqno; // Database description sequence number.
list<Lsa_header> _lsa_headers;
};
/**
* Link State Request Packet
*/
class LinkStateRequestPacket : public Packet {
public:
LinkStateRequestPacket(OspfTypes::Version version)
: Packet(version)
{}
OspfTypes::Type get_type() const { return 3; }
Packet *decode(uint8_t *ptr, size_t len) const throw(InvalidPacket);
/**
* Encode the packet.
*
* @param pkt vector into which the packet should be placed.
* @return true if the encoding succeeded.
*/
bool encode(vector<uint8_t>& pkt);
list<Ls_request>& get_ls_request() {
return _ls_request;
}
/**
* Generate a printable representation of the packet.
*/
string str() const;
private:
list<Ls_request> _ls_request;
};
/**
* Link State Update Packet
*/
class LinkStateUpdatePacket : public Packet {
public:
LinkStateUpdatePacket(OspfTypes::Version version, LsaDecoder& lsa_decoder)
: Packet(version), _lsa_decoder(lsa_decoder)
{}
OspfTypes::Type get_type() const { return 4; }
Packet *decode(uint8_t *ptr, size_t len) const throw(InvalidPacket);
/**
* Encode the packet.
*
* @param pkt vector into which the packet should be placed.
* @return true if the encoding succeeded.
*/
bool encode(vector<uint8_t>& pkt);
/**
* Encode the packet.
*
* @param pkt vector into which the packet should be placed.
* @param inftransdelay add this delay to the age field of each LSA.
* @return true if the encoding succeeded.
*/
bool encode(vector<uint8_t>& pkt, uint16_t inftransdelay);
list<Lsa::LsaRef>& get_lsas() {
return _lsas;
}
/**
* Generate a printable representation of the packet.
*/
string str() const;
private:
LsaDecoder& _lsa_decoder; // LSA decoders.
// The packet contains a field with the number of LSAs that it
// contains there is no point in storing it.
list<Lsa::LsaRef> _lsas; // The list of LSAs in the packet.
};
/**
* Link State Acknowledgement Packet
*/
class LinkStateAcknowledgementPacket : public Packet {
public:
LinkStateAcknowledgementPacket(OspfTypes::Version version)
: Packet(version)
{}
OspfTypes::Type get_type() const { return 5; }
Packet *decode(uint8_t *ptr, size_t len) const throw(InvalidPacket);
/**
* Encode the packet.
*
* @param pkt vector into which the packet should be placed.
* @return true if the encoding succeeded.
*/
bool encode(vector<uint8_t>& pkt);
list<Lsa_header>& get_lsa_headers() {
return _lsa_headers;
}
/**
* Generate a printable representation of the packet.
*/
string str() const;
private:
list<Lsa_header> _lsa_headers;
};
/**
* The definitive list of packets. All decoder lists should be primed
* using this function.
*/
inline
void
initialise_packet_decoder(OspfTypes::Version version,
PacketDecoder& packet_decoder,
LsaDecoder& lsa_decoder)
{
packet_decoder.register_decoder(new HelloPacket(version));
packet_decoder.register_decoder(new DataDescriptionPacket(version));
packet_decoder.register_decoder(new LinkStateUpdatePacket(version,
lsa_decoder));
packet_decoder.register_decoder(new LinkStateRequestPacket(version));
packet_decoder.
register_decoder(new LinkStateAcknowledgementPacket(version));
}
/**
* Helper class to manipulate the options field in packets and LSAs.
*/
class Options {
public:
static const uint32_t V6_bit = 0x1;
static const uint32_t E_bit = 0x2;
static const uint32_t MC_bit = 0x4;
static const uint32_t N_bit = 0x8;
static const uint32_t P_bit = N_bit;
static const uint32_t R_bit = 0x10;
static const uint32_t EA_bit = 0x10;
static const uint32_t DC_bit = 0x20;
Options(OspfTypes::Version version, uint32_t options)
: _version(version), _options(options)
{
}
void set_bit(bool set, uint32_t bit) {
if (set)
_options |= bit;
else
_options &= ~bit;
}
bool get_bit(uint32_t bit) const { return _options & bit ? true : false; }
void set_v6_bit(bool set) {
XLOG_ASSERT(OspfTypes::V3 == _version);
set_bit(set, V6_bit);
}
bool get_v6_bit() const {
XLOG_ASSERT(OspfTypes::V3 == _version);
return get_bit(V6_bit);
}
void set_e_bit(bool set) { set_bit(set, E_bit); }
bool get_e_bit() const { return get_bit(E_bit); }
void set_mc_bit(bool set) { set_bit(set, MC_bit); }
bool get_mc_bit() const { return get_bit(MC_bit); }
void set_n_bit(bool set) { set_bit(set, N_bit); }
bool get_n_bit() const { return get_bit(N_bit); }
void set_p_bit(bool set) { set_n_bit(set); }
bool get_p_bit() const { return get_n_bit(); }
void set_r_bit(bool set) {
XLOG_ASSERT(OspfTypes::V3 == _version);
set_bit(set, R_bit);
}
bool get_r_bit() const {
XLOG_ASSERT(OspfTypes::V3 == _version);
return get_bit(R_bit);
}
void set_ea_bit(bool set) {
XLOG_ASSERT(OspfTypes::V2 == _version);
set_bit(set, EA_bit);
}
bool get_ea_bit() const {
XLOG_ASSERT(OspfTypes::V2 == _version);
return get_bit(EA_bit);
}
void set_dc_bit(bool set) { set_bit(set, DC_bit); }
bool get_dc_bit() const { return get_bit(DC_bit); }
uint32_t get_options() { return _options; }
string pp_bool(bool val) const { return val ? "1" : "0"; }
string str() const {
string out;
switch(_version) {
case OspfTypes::V2:
out = "DC: " + pp_bool(get_dc_bit());
out += " EA: " + pp_bool(get_ea_bit());
out += " N/P: " + pp_bool(get_n_bit());
out += " MC: " + pp_bool(get_mc_bit());
out += " E: " + pp_bool(get_e_bit());
break;
case OspfTypes::V3:
out = "DC: " + pp_bool(get_dc_bit());
out += " R: " + pp_bool(get_r_bit());
out += " N: " + pp_bool(get_n_bit());
out += " MC: " + pp_bool(get_mc_bit());
out += " E: " + pp_bool(get_e_bit());
out += " V6: " + pp_bool(get_v6_bit());
break;
}
return out;
}
private:
OspfTypes::Version _version;
uint32_t _options;
};
/**
* Verify the checksum of an IPv6 PDU, throw an exception if the
* checksum doesn't match.
*
* In IPv6 the payload is not checksummed it is up to the protocol to
* checksum its own payload. The checksum includes a pseduo header
* that is described in RFC 2460 section 8.1
*
* @param src Source address of packet.
* @param dst Destination address of packet.
* @param data pointer to payload.
* @param len length of payload.
* @param checksum_offset offset of checksum in the payload.
* @param protocol protocol number.
*/
template <typename A>
void
ipv6_checksum_verify(const A& src, const A& dst,
const uint8_t *data, size_t len,
size_t checksum_offset, uint8_t protocol)
throw(InvalidPacket);
/**
* Compute the IPv6 checksum and apply it to the packet provided. If
* the checksum_offset is outside the packet then an exception is thrown.
*
* In IPv6 the payload is not checksummed it is up to the protocol to
* checksum its own payload. The checksum includes a pseduo header
* that is described in RFC 2460 section 8.1
*
* @param src Source address of packet.
* @param dst Destination address of packet.
* @param data pointer to payload.
* @param len length of payload.
* @param checksum_offset offset of checksum in the payload.
* @param protocol protocol number.
*/
template <typename A>
void
ipv6_checksum_apply(const A& src, const A& dst,
uint8_t *data, size_t len,
size_t checksum_offset, uint8_t protocol)
throw(InvalidPacket);
#endif // __OSPF_PACKET_HH__
Generated by: pavlin on possum.icir.org on Wed Mar 21 11:23:58 2007, using kdoc $.
