2 // Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
3 // Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
4 // Stefan Bund <g0dil@berlios.de>
6 // This program is free software; you can redistribute it and/or modify
7 // it under the terms of the GNU General Public License as published by
8 // the Free Software Foundation; either version 2 of the License, or
9 // (at your option) any later version.
11 // This program is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // You should have received a copy of the GNU General Public License
17 // along with this program; if not, write to the
18 // Free Software Foundation, Inc.,
19 // 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22 \brief Packet public header */
28 #include <boost/operators.hpp>
30 #include "Utils/Exception.hh"
31 #include "Utils/SafeBool.hh"
32 #include "PacketInterpreter.hh"
34 //#include "Packet.mpp"
35 ///////////////////////////////hh.p////////////////////////////////////////
39 /** \defgroup packet_module Packet Handling
41 The basic groundwork of the Packet library is the packet handling:
43 \li The packet classes provide access to a chain of packet headers (more generically called
45 \li They automatically manage the required memory resources and the shared packet data.
47 \section packet_module_chain The Interpreter Chain
49 The central data structure for a packet is the interpreter chain
51 \image html structure.png The Interpreter Chain
53 This image depicts a packet with several headers. Each interpreter is responsible for a
54 specific sub-range of the complete packet. This range always \e includes the packets payload
55 (This is, why we call the data structure interpreter and not header: The interpreter is
56 responsible for interpreting a range of the packet according to a specific protocol), the
57 packet interpreters are nested inside each other.
59 For each interpreter, this structure automatically divides the packet into three areas (each
60 of which are optional): The header, the payload and the trailer. Every packet will have
61 either a header or a payload section while most don't have a trailer.
63 As user of the library you always interact with the chain through one (or more) of the
64 interpreters. The interpreter provides methods to traverse to the following or preceding
65 header (interpreter) and provides two levels of access to the packet data: Generic low-level
66 access in the form of an STL compatible sequence and access to the parsed fields which are
67 provided by the parser associated with the concrete packet type.
69 \section packet_module_management Resource Management
71 The interface to the packet library is provided using a handle class (\ref Packet for
72 generic, protocol agnostic access and \ref ConcretePacket derived from \ref Packet to access
73 a specific protocol). This handle automatically manages the resources associated with the
74 packet (the interpreter chain and the data storage holding the packet data). The resources
75 are automatically released when the last packet handle referencing a specific packet is
78 \implementation The packet chain is provided on two levels: The internal representation \ref
79 PacketInterpreterBase and \ref PacketInterpreter which are referenced by the Handle
80 classes \ref Packet and \ref ConcretePacket. \n
81 The internal representation classes are pertinent in the sense, that they exist
82 regardless of the existence of a handle referencing them (as long as the packet
83 exists). Still the interpreter chain is lazy and packet interpreters beside the first
84 are only created dynamically when accessed (this is implemented in the handle not in the
85 internal representation). \n
86 The packet interpreters make use of a pool allocator. This provides extremely efficient
87 creation and destruction of packet interpreter's and removes the dynamic memory
88 management overhead from the packet interpreter management. The packet implementation
89 class (\ref PacketImpl which holds the packet data itself) however is still dynamically
90 managed (however there is only a single instance for each packet).
93 template <class PackeType> class ConcretePacket;
95 ///\addtogroup packet_module
98 /** \brief Main Packet class
100 Packet is the main externally visible class of the packet library. Packet is a handle into
101 the internal packet representation. From Packet you may access the data of that specific
102 sub-packet/header/interpreter and navigate to the neighboring
103 sub-packets/headers/interpreters.
105 Packet is protocol agnostic. This class only provides non-protocol dependent members. To
106 access the protocol specific features of a packet (like header fields) the ConcretePacket
107 class extending Packet is povided.
109 \section packet_semantics Semantics
111 All operations accessing the data of \c this packet in some way will ignore any preceding
112 packets/headers/interpreters in the chain. It does not matter, whether a given packet is
113 taken from the middle or the beginning of the chain, all operations (except those explicitly
114 accessing the chain of course) should work the same.
116 This especially includes members like clone() or append(): clone() will clone \e only from
117 \c this packet until the end of the chain, append() will append the given packet \e ignoring
118 any possibly preceding packets/headers/interpreters.
120 In the same way, the data() member provides an STL-sequence compatible view of the packet
121 data. This only includes the data which is part of \c this packet including header, trailer
122 \e and payload but \e not the headers or trailers of packets \e before \c this packet in the
123 packet/header/interpreter chain (nonetheless, this data overlaps with the data of other
126 Several members are member templates taking an \a OtherPacket template parameter. This
127 parameter must be the ConcretePacket instantiation associated with some concrete packet type
128 (protocol). For each implemented protocol, typedefs should be provided for these
129 instantiations (Example: \ref EthernetPacket is a typedef for
130 \ref ConcretePacket < \ref EthernetPacketType >).
133 : public SafeBool<Packet>,
134 public boost::equality_comparable<Packet>
137 ///////////////////////////////////////////////////////////////////////////
140 typedef void type; ///< Type of the packet.
141 typedef senf::detail::packet::size_type size_type; ///< Unsigned type to represent packet size
142 typedef PacketInterpreterBase::factory_t factory_t; ///< Packet factory type (see below)
144 /// Special argument flag
145 /** Used in some ConcretePacket constructors */
146 enum NoInit_t { noinit };
148 ///////////////////////////////////////////////////////////////////////////
149 ///\name Structors and default members
152 // default copy constructor
153 // default copy assignment
154 // default destructor
156 Packet(); ///< Create uninitialized packet handle
157 /**< An uninitialized handle is not valid(). It does not
158 allow any operation except assignment and checking for
160 Packet clone() const; ///< Create copy packet
161 /**< clone() will create a complete copy the packet. The
162 returned packet will have the same data and packet
163 chain. It does however not share any data with the
166 // conversion constructors
168 template <class PacketType>
169 Packet(ConcretePacket<PacketType> packet); ///< Copy-construct Packet from ConcretePacket
170 /**< This constructor allows to convert an arbitrary
171 ConcretePacket into a general Packet, loosing the
172 protocol specific interface. */
175 ///////////////////////////////////////////////////////////////////////////
177 ///\name Interpreter chain access
181 ///< Get next packet in chain
182 template <class OtherPacket> OtherPacket next() const;
183 ///< Get next packet of given type in chain
184 /**< \throws InvalidPacketChainException if no such packet
186 template <class OtherPacket> OtherPacket next(NoThrow_t) const;
187 ///< Get next packet of given type in chain
188 /**< \param[in] nothrow This argument always has the value
190 \returns in-valid() packet, if no such packet is found */
191 template <class OtherPacket> OtherPacket findNext() const;
192 ///< Find next packet of given type in chain
193 /**< findNext() is like next(), it will however return \c
194 *this if it is of the given type.
195 \throws InvalidPacketChainException if no such packet
197 template <class OtherPacket> OtherPacket findNext(NoThrow_t) const;
198 ///< Find next packet of given type in chain
199 /**< findNext() is like next(), it will however return \c
200 *this if it is of the given type.
201 \param[in] nothrow This argument always has the value
203 \returns in-valid() packet, if no such packet is found */
207 ///< Get previous packet in chain
208 template <class OtherPacket> OtherPacket prev() const;
209 ///< Get previous packet of given type in chain
210 /**< \throws InvalidPacketChainException if no such packet
212 template <class OtherPacket> OtherPacket prev(NoThrow_t) const;
213 ///< Get previous packet of given type in chain
214 /**< \param[in] nothrow This argument always has the value
216 \returns in-valid() packet, if no such packet is found */
217 template <class OtherPacket> OtherPacket findPrev() const;
218 ///< Find previous packet of given type in chain
219 /**< findPrev() is like prev(), it will however return \c
220 *this if it is of the type
221 \throws InvalidPacketChainException if no such packet
223 template <class OtherPacket> OtherPacket findPrev(NoThrow_t) const;
224 ///< Find previous packet of given type in chain
225 /**< findPrev() is like prev(), it will however return \c
226 *this if it is of the type
227 \param[in] nothrow This argument always has the value
229 \returns in-valid() packet, if no such packet is found */
232 Packet first() const;
233 ///< Return first packet in chain
234 template <class OtherPacket> OtherPacket first() const;
235 ///< Return first packet of given type in chain
236 /**< \throws InvalidPacketChainException if no such packet
238 template <class OtherPacket> OtherPacket first(NoThrow_t) const;
239 ///< Return first packet of given type in chain
240 /**< \param[in] nothrow This argument always has the value
242 \returns in-valid() packet, if no such packet is found */
245 ///< Return last packet in chain
246 template <class OtherPacket> OtherPacket last() const;
247 ///< Return last packet of given type in chain
248 /**< \throws InvalidPacketChainException if no such packet
250 template <class OtherPacket> OtherPacket last(NoThrow_t) const;
251 ///< Return last packet of given type in chain
252 /**< \param[in] nothrow This argument always has the value
254 \returns in-valid() packet, if no such packet is found */
257 template <class OtherPacket> OtherPacket parseNextAs() const;
258 ///< Parse payload as given by \a OtherPacket and add packet
259 /**< parseNextAs() will throw away the packet chain after
260 the current packet if necessary. It will then parse the
261 payload section of \c this packet as given by \a
262 OtherPacket. The new packet is added to the chain after
264 \returns new packet instance sharing the same data and
265 placed after \c this packet in the chain. */
266 Packet parseNextAs(factory_t factory) const;
267 ///< Parse payload as given by \a factory and add packet
268 /**< parseNextAs() will throw away the packet chain after
269 the current packet if necessary. It will then parse the
270 payload section of \c this packet as given by \a
271 OtherPacket. The new packet is added to the chain after
273 \returns new packet instance sharing the same data and
274 placed after \c this packet in the chain. */
275 template <class OtherPacket> bool is() const;
276 ///< Check, whether \c this packet is of the given type
277 template <class OtherPacket> OtherPacket as() const;
278 ///< Cast current packet to the given type
279 /**< This operations returns a handle to the same packet
280 header/interpreter however cast to the given
281 ConcretePacket type. <b>This conversion is
282 unchecked</b>. If the packet really is of a different
283 type, this will wreak havoc with the packet
284 data-structures. You can validate whether the
285 conversion is valid using is(). */
287 Packet append(Packet packet) const; ///< Append the given packet to \c this packet
288 /**< This operation will replace the payload section of \c
289 this packet with \a packet. This operation will replace
290 the packet chain after \c this packet with a clone of
291 \a packet and will replace the raw data of the payload
292 of \c this with the raw data if \a packet.
293 \returns Packet handle to the cloned \a packet, placed
294 after \c this in the packet/header/interpreter
302 PacketData & data() const; ///< Access the packets raw data container
303 size_type size() const; ///< Return size of packet in bytes
304 /**< This size does \e not include the size of any preceding
305 headers/packets/interpreters. It does however include
306 \c this packets payload. */
310 ///\name Other methods
313 bool operator==(Packet other) const; ///< Check for packet identity
314 /**< Two packet handles compare equal if they really are the
315 same packet header in the same packet chain. */
316 bool boolean_test() const; ///< Check, whether the packet is valid()
318 bool valid() const; ///< Check, whether the packet is valid()
319 /**< An in-valid() packet does not allow any operation
320 except checking vor validity and assignment. in-valid()
321 packets serve the same role as 0-pointers. */
324 void finalize() const; ///< Update calculated fields
325 /**< This call will update all calculated fields of the
326 packet after it has been created or changed. This
327 includes checksums, payload size fields or other
328 fields, which can be set from other information in the
329 packet. Each concrete packet type should document,
330 which fields are set by finalize().
332 finalize() will automatically process all
333 packets/headers/interpreters from the end of the chain
334 backwards up to \c this. */
336 void dump(std::ostream & os) const; ///< Write out a printable packet representation
337 /**< This method is provided mostly to help debugging packet
338 problems. Each concrete packet should implement a dump
339 method writing out all fields of the packet in a
340 readable reresentation. dump() will call this member
341 for each packet/header/interpreter in the chain from \c
342 this packet up to the end of the chain. */
344 TypeIdValue typeId() const; ///< Get id of \c this packet
345 /**< This value is used e.g. in the packet registry to
346 associate packet types with other information.
347 \returns A type holding the same information as a
348 type_info object, albeit assignable */
349 factory_t factory() const; ///< Return factory instance of \c this packet
350 /**< The returned factory instance can be used to create new
351 packets of the given type without knowing the concrete
352 type of the packet. The valid may be stored away for
353 later use if needed. */
358 explicit Packet(PacketInterpreterBase::ptr packet);
360 PacketInterpreterBase::ptr ptr() const;
363 Packet checkNext() const;
364 Packet checkLast() const;
366 PacketInterpreterBase::ptr packet_;
368 template <class PacketType>
369 friend class ConcretePacket;
372 /** \brief Protocol specific packet handle
374 The ConcretePacket template class extends Packet to provide protocol/packet type specific
375 aspects. These are packet constructors and access to the parsed packet fields.
377 The \c PacketType template argument to ConcretePacket is a protocol specific and internal
378 policy class which defines the protocol specific behavior. To access a specific type of
379 packet, the library provides corresponding typedefs of ConcretePacket < \a SomePacketType >
380 (e.g. \ref EthernetPacket as typedef for \ref ConcretePacket < \ref EthernetPacketType >).
382 The new members provided by ConcretePacket over packet are mostly comprised of the packet
383 constructors. These come in three major flavors:
385 \li The create() family of constructors will create completely new packets.
386 \li The createAfter() family of constructors will create new packets (with new data for the
387 packet) \e after a given existing packet.
388 \li The createBefore() family of constructors will create new packets (again with new data)
389 \e before a given existing packet.
391 Whereas create() will create a completely new packet with it's own chain and data storage,
392 createAfter() and createBefore() extend a packet with additional
393 headers/interpreters. createAfter() will set the payload of the given packet to the new
394 packet whereas createBefore() will create a new packet with the existing packet as it's
397 createAfter() differs from Packet::parseNextAs() in that the former creates a new packet \e
398 replacing any possibly existing data whereas the latter will interpret the already \e
399 existing data as given by the type argument.
401 \see \ref PacketTypeBase for a specification of the interface to be provided by the \a
402 PacketType policy class.
404 template <class PacketType>
409 ///////////////////////////////////////////////////////////////////////////
412 typedef PacketType type;
414 ///////////////////////////////////////////////////////////////////////////
415 ///\name Structors and default members
418 // default copy constructor
419 // default copy assignment
420 // default destructor
421 // no conversion constructors
423 ConcretePacket(); ///< Create uninitialized packet handle
424 /**< An uninitialized handle is not valid(). It does not
425 allow any operation except assignment and checking for
428 static factory_t factory(); ///< Return factory for packets of specific type
429 /**< This \e static member is like Packet::factory() for a
430 specific packet of type \a PacketType */
432 // Create completely new packet
434 static ConcretePacket create(); ///< Create default initialized packet
435 /**< The packet will be initialized to it's default empty
437 static ConcretePacket create(NoInit_t); ///< Create uninitialized empty packet
438 /**< This will create a completely empty and uninitialized
439 packet with <tt>size() == 0</tt>.
440 \param[in] noinit This parameter must always have the
441 value \c senf::noinit. */
442 static ConcretePacket create(size_type size); ///< Create default initialized packet
443 /**< This member will create a default initialized packet
444 with the given size. If the size parameter is smaller
445 than the minimum allowed packet size an exception will
447 \param[in] size Size of the packet to create in bytes.
448 \throws TruncatedPacketException if \a size is smaller
449 than the smallest permissible size for this type of
451 static ConcretePacket create(size_type size, NoInit_t); ///< Create uninitialized packet
452 /**< Creates an uninitialized (all-zero) packet of the exact
454 \param[in] size Size of the packet to create in bytes
455 \param[in] noinit This parameter must always have the
456 value \c senf::noinit. */
457 template <class ForwardReadableRange>
458 static ConcretePacket create(ForwardReadableRange const & range);
459 ///< Create packet from given data
460 /**< The packet will be created from a copy of the given
461 data. The data from the range will be copied directly
462 into the packet representation. The data will \e not be
463 validated in any way.
465 href="http://www.boost.org/libs/range/index.html">Boost.Range</a>
466 of data to construct packet from. */
468 // Create packet as new packet after a given packet
470 static ConcretePacket createAfter(Packet packet);
471 ///< Create default initialized packet after \a packet
472 /**< The packet will be initialized to it's default empty
473 state. It will be appended as next header/interpreter
474 after \a packet in that packets interpreter chain.
475 \param[in] packet Packet to append new packet to. */
476 static ConcretePacket createAfter(Packet packet, NoInit_t);
477 ///< Create uninitialized empty packet after\a packet
478 /**< This will create a completely empty and uninitialized
479 packet with <tt>size() == 0</tt>. It will be appended
480 as next header/interpreter after \a packet in that
481 packets interpreter chain.
482 \param[in] packet Packet to append new packet to.
483 \param[in] noinit This parameter must always have the
484 value \c senf::noinit. */
485 static ConcretePacket createAfter(Packet packet, size_type size);
486 ///< Create default initializzed packet after \a packet
487 /**< This member will create a default initialized packet
488 with the given size. If the size parameter is smaller
489 than the minimum allowed packet size an exception will
490 be thrown. It will be appended as next
491 header/interpreter after \a packet in that packets
493 \param[in] packet Packet to append new packet to.
494 \param[in] size Size of the packet to create in bytes.
495 \throws TruncatedPacketException if \a size is smaller
496 than the smallest permissible size for this type of
498 static ConcretePacket createAfter(Packet packet, size_type size, NoInit_t);
499 ///< Create uninitialized packet after \a packet
500 /**< Creates an uninitialized (all-zero) packet of the exact
501 given size. It will be appended as next
502 header/interpreter after \a packet in that packets
504 \param[in] packet Packet to append new packet to.
505 \param[in] size Size of the packet to create in bytes
506 \param[in] noinit This parameter must always have the
507 value \c senf::noinit. */
508 template <class ForwardReadableRange>
509 static ConcretePacket createAfter(Packet packet,
510 ForwardReadableRange const & range);
511 ///< Create packet from given data after \a packet
512 /**< The packet will be created from a copy of the given
513 data. The data from the range will be copied directly
514 into the packet representation. The data will \e not be
515 validated in any way. It will be appended as next
516 header/interpreter after \a packet in that packets
518 \param[in] packet Packet to append new packet to.
520 href="http://www.boost.org/libs/range/index.html">Boost.Range</a>
521 of data to construct packet from. */
523 // Create packet as new packet (header) before a given packet
525 static ConcretePacket createBefore(Packet packet);
526 ///< Create default initialized packet before \a packet
527 /**< The packet will be initialized to it's default empty
528 state. It will be prepended as previous
529 header/interpreter before \a packet in that packets
531 \param[in] packet Packet to prepend new packet to. */
532 static ConcretePacket createBefore(Packet packet, NoInit_t);
533 ///< Create uninitialized empty packet before \a packet
534 /**< Creates a completely empty and uninitialized packet. It
535 will be prepended as previous header/interpreter before
536 \a packet in that packets interpreter chain.
537 \param[in] packet Packet to prepend new packet to. */
539 // Create a clone of the current packet
541 ConcretePacket clone() const;
544 ///////////////////////////////////////////////////////////////////////////
548 typename type::parser * operator->() const; ///< Access packet fields
549 /**< This operator allows to access the parsed fields of the
550 packet using the notation <tt>packet->field()</tt>. The
551 fields of the packet are specified by the PacketType's
554 The members are not strictly restricted to simple field
555 access. The parser class may have any member which is
556 needed for full packet access (e.g. checksum validation
558 \see \ref packetparser for the parser interface. */
563 typedef PacketInterpreter<PacketType> interpreter;
565 ConcretePacket(typename interpreter::ptr packet_);
567 typename interpreter::ptr ptr() const;
570 friend class PacketInterpreter<PacketType>;
577 ///////////////////////////////hh.e////////////////////////////////////////
578 #include "Packet.cci"
580 #include "Packet.cti"
587 // c-file-style: "senf"
588 // indent-tabs-mode: nil
589 // ispell-local-dictionary: "american"
590 // compile-command: "scons -u test"
591 // comment-column: 40