4 // Fraunhofer Institute for Open Communication Systems (FOKUS)
5 // Competence Center NETwork research (NET), St. Augustin, GERMANY
6 // Stefan Bund <g0dil@berlios.de>
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 2 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the
20 // Free Software Foundation, Inc.,
21 // 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24 \brief Packet public header */
30 #include <boost/operators.hpp>
31 #include <boost/utility.hpp>
32 #include <boost/type_traits/is_integral.hpp>
33 #include "../Utils/Exception.hh"
34 #include "../Utils/Tags.hh"
35 #include "../Utils/safe_bool.hh"
36 #include "PacketInterpreter.hh"
38 //#include "Packet.mpp"
39 ///////////////////////////////hh.p////////////////////////////////////////
43 /** \defgroup packet_module Packet Handling
45 The basic groundwork of the %Packet library is the packet handling:
47 \li The packet classes provide access to a chain of packet headers (more generically called
49 \li They automatically manage the required memory resources and the shared packet data.
51 \section packet_module_chain The Interpreter Chain
53 The central data structure for a packet is the interpreter chain
55 \image html structure.png The Interpreter Chain
57 This image depicts a packet with several headers. Each interpreter is responsible for a
58 specific sub-range of the complete packet. This range always \e includes the packets payload
59 (This is, why we call the data structure interpreter and not header: The interpreter is
60 responsible for interpreting a range of the packet according to a specific protocol), the
61 packet interpreters are nested inside each other.
63 For each interpreter, this structure automatically divides the packet into three areas (each
64 of which are optional): The header, the payload and the trailer. Every packet will have
65 either a header or a payload section while most don't have a trailer.
67 As user of the library you always interact with the chain through one (or more) of the
68 interpreters. The interpreter provides methods to traverse to the following or preceding
69 header (interpreter) and provides two levels of access to the packet data: Generic low-level
70 access in the form of an STL compatible sequence and access to the parsed fields which are
71 provided by the parser associated with the concrete packet type.
73 \section packet_module_management Resource Management
75 The interface to the packet library is provided using a handle class (\ref Packet for
76 generic, protocol agnostic access and \ref ConcretePacket derived from \ref Packet to access
77 a specific protocol). This handle automatically manages the resources associated with the
78 packet (the interpreter chain and the data storage holding the packet data). The resources
79 are automatically released when the last packet handle referencing a specific packet is
82 \implementation The packet chain is provided on two levels: The internal representation \ref
83 PacketInterpreterBase and \ref PacketInterpreter which are referenced by the Handle
84 classes \ref Packet and \ref ConcretePacket. \n
85 The internal representation classes are pertinent in the sense, that they exist
86 regardless of the existence of a handle referencing them (as long as the packet
87 exists). Still the interpreter chain is lazy and packet interpreters beside the first
88 are only created dynamically when accessed (this is implemented in the handle not in the
89 internal representation). \n
90 The packet interpreters make use of a pool allocator. This provides extremely efficient
91 creation and destruction of packet interpreter's and removes the dynamic memory
92 management overhead from the packet interpreter management. The packet implementation
93 class (\ref PacketImpl which holds the packet data itself) however is still dynamically
94 managed (however there is only a single instance for each packet).
97 template <class PackeType> class ConcretePacket;
99 ///\addtogroup packet_module
102 /** \brief Main %Packet class
104 %Packet is the main externally visible class of the packet library. %Packet is a handle into
105 the internal packet representation. From %Packet you may access the data of that specific
106 sub-packet/header/interpreter and navigate to the neighboring
107 sub-packets/headers/interpreters.
109 %Packet is protocol agnostic. This class only provides non-protocol dependent members. To
110 access the protocol specific features of a packet (like header fields) the ConcretePacket
111 class extending %Packet is provided.
113 \section packet_semantics Semantics
115 All operations accessing the data of \c this packet in some way will ignore any preceding
116 packets/headers/interpreters in the chain. It does not matter, whether a given packet is
117 taken from the middle or the beginning of the chain, all operations (except those explicitly
118 accessing the chain of course) should work the same.
120 This especially includes members like clone() or append(): clone() will clone \e only from
121 \c this packet until the end of the chain, append() will append the given packet \e ignoring
122 any possibly preceding packets/headers/interpreters.
124 In the same way, the data() member provides an STL-sequence compatible view of the packet
125 data. This only includes the data which is part of \c this packet including header, trailer
126 \e and payload but \e not the headers or trailers of packets \e before \c this packet in the
127 packet/header/interpreter chain (nonetheless, this data overlaps with the data of other
130 Several members are member templates taking an \a OtherPacket template parameter. This
131 parameter must be the ConcretePacket instantiation associated with some concrete packet type
132 (protocol). For each implemented protocol, typedefs should be provided for these
133 instantiations (Example: \ref EthernetPacket is a typedef for
134 \ref ConcretePacket < \ref EthernetPacketType >).
137 \ref ConcretePacket for the %type specific interface\n
138 \ref PacketData for the sequence interface\n
139 \ref packetparser for a specification of the parser interface
142 : public safe_bool<Packet>,
143 public boost::equality_comparable<Packet>
146 ///////////////////////////////////////////////////////////////////////////
149 typedef void type; ///< Type of the packet.
150 typedef senf::detail::packet::size_type size_type;
151 ///< Unsigned type to represent packet size
152 typedef PacketInterpreterBase::factory_t factory_t; ///< Packet factory type (see below)
154 ///////////////////////////////////////////////////////////////////////////
155 ///\name Structors and default members
158 // default copy constructor
159 // default copy assignment
160 // default destructor
162 Packet(); ///< Create uninitialized packet handle
163 /**< An uninitialized handle is in - valid(). It does not
164 allow any operation except assignment and checking for
166 Packet clone() const; ///< Create copy packet
167 /**< clone() will create a complete copy of \c this
168 packet. The returned packet will have the same data and
169 packet chain. It does however not share any data with
170 the original packet. */
172 // conversion constructors
174 template <class PacketType>
175 Packet(ConcretePacket<PacketType> packet); ///< Copy-construct Packet from ConcretePacket
176 /**< This constructor allows to convert an arbitrary
177 ConcretePacket into a general Packet, loosing the
178 protocol specific interface. */
181 ///////////////////////////////////////////////////////////////////////////
183 ///\name Interpreter chain access
187 ///< Get next packet in chain
188 /**< \throws InvalidPacketChainException if no next packet
190 Packet next(NoThrow_t) const;
191 ///< Get next packet in chain
192 /**< \returns in - valid() packet if no next packet
194 template <class OtherPacket> OtherPacket next() const;
195 ///< Get next packet in chain and cast to \a OtherPacket
196 /**< \throws std::bad_cast if the next() packet is not of
198 \throws InvalidPacketChainException if no next packet
200 template <class OtherPacket> OtherPacket next(NoThrow_t) const;
201 ///< Get next packet in chain and cast to \a OtherPacket
202 /**< \throws std::bad_cast if the next() packet is not of
204 \returns in - valid() packet if no next packet
206 template <class OtherPacket> OtherPacket find() const;
207 ///< Search chain forward for packet of type \a OtherPacket
208 /**< The search will start with the current packet.
209 \throws InvalidPacketChainException if no packet of
210 type \a OtherPacket can be found. */
211 template <class OtherPacket> OtherPacket find(NoThrow_t) const;
212 ///< Search chain forward for packet of type \a OtherPacket
213 /**< The search will start with the current packet.
214 \returns in - valid() packet if no packet of type \a
215 OtherPacket can be found. */
218 ///< Get previous packet in chain
219 /**< \throws InvalidPacketChainException if no previous
221 Packet prev(NoThrow_t) const;
222 ///< Get previous packet in chain
223 /**< \returns in - valid() packet if no previous packet
225 template <class OtherPacket> OtherPacket prev() const;
226 ///< Get previous packet in chain and cast to \a OtherPacket
227 /**< \throws std::bad_cast, if the previous packet is not of
229 \throws InvalidPacketChainException if no previous
231 template <class OtherPacket> OtherPacket prev(NoThrow_t) const;
232 ///< Get previous packet in chain and cast to \a OtherPacket
233 /**< \throws std::bad_cast, if the previous packet is not of
235 \returns in - valid() packet if no previous packet
237 template <class OtherPacket> OtherPacket rfind() const;
238 ///< Search chain backwards for packet of type \a OtherPacket
239 /**< The search will start with the current packet.
240 \throws InvalidPacketChainException if no packet of
241 type \a OtherPacket can be found. */
242 template <class OtherPacket> OtherPacket rfind(NoThrow_t) const;
243 ///< Search chain backwards for packet of type \a OtherPacket
244 /**< The search will start with the current packet.
245 \returns in - valid() packet if no packet of type \a
246 OtherPacket can be found. */
249 Packet first() const;
250 ///< Return first packet in chain
251 template <class OtherPacket> OtherPacket first() const;
252 ///< Return first packet in chain and cast
253 /**< \throws std::bad_cast if the first() packet is not of
254 type \a OtherPacket */
257 ///< Return last packet in chain
258 template <class OtherPacket> OtherPacket last() const;
259 ///< Return last packet in chain and cast
260 /**< \throws std::bad_cast if the last() packet is not of
261 type \a OtherPacket */
264 template <class OtherPacket> OtherPacket parseNextAs() const;
265 ///< Interpret payload of \c this as \a OtherPacket
266 /**< parseNextAs() will throw away the packet chain after
267 the current packet if necessary. It will then parse the
268 payload section of \c this packet as given by \a
269 OtherPacket. The new packet is added to the chain after
271 \returns new packet instance sharing the same data and
272 placed after \c this packet in the chain. */
273 Packet parseNextAs(factory_t factory) const;
274 ///< Interpret payload of \c this as \a factory type packet
275 /**< parseNextAs() will throw away the packet chain after
276 the current packet if necessary. It will then parse the
277 payload section of \c this packet as given by \a
278 factory. The new packet is added to the chain after
280 \returns new packet instance sharing the same data and
281 placed after \c this packet in the chain. */
283 template <class OtherPacket> bool is() const;
284 ///< Check, whether \c this packet is of the given type
285 template <class OtherPacket> OtherPacket as() const;
286 ///< Cast current packet to the given type
287 /**< This operations returns a handle to the same packet
288 header/interpreter however cast to the given
290 \throws std::bad_cast if the current packet is not of
291 type \a OtherPacket */
293 Packet append(Packet packet) const; ///< Append the given packet to \c this packet
294 /**< This operation will replace the payload section of \c
295 this packet with \a packet. This operation will replace
296 the packet chain after \c this packet with a clone of
297 \a packet and will replace the raw data of the payload
298 of \c this with the raw data of \a packet. \c this
299 packet will not share any date with \a packet.
300 \returns Packet handle to the cloned \a packet, placed
301 after \c this in the packet/header/interpreter
309 PacketData & data() const; ///< Access the packets raw data container
310 size_type size() const; ///< Return size of packet in bytes
311 /**< This size does \e not include the size of any preceding
312 headers/packets/interpreters. It does however include
313 \c this packets payload. */
320 template <class Annotation>
321 Annotation & annotation(); ///< Get packet annotation
322 /**< This member will retrieve an arbitrary packet
323 annotation. Every annotation is identified by a unique
324 \a Annotation type. This type should \e always be a \c
328 struct MyAnnotation {
332 senf::Packet p (...);
334 p.annotation<MyAnnotation>().value = 1;
337 Annotations are shared by all headers / interpreters
338 within a single packet chain.
340 If an annotation is \e not a POD type (more
341 specifically, if it's constructor or destructor is not
342 trivial), the \a Annotation type \e must inherit from
343 senf::ComplexAnnotation. Failing to follow this rule
344 will result in undefined behavior and will probably
345 lead to a program crash.
348 struct MyStringAnnotation : senf::ComplexAnnotation {
353 \implementation The annotation system is implemented
354 quite efficiently since annotations are stored
355 within a packet embedded vector of fixed size (the
356 size is determined automatically at runtime by the
357 number of different annotations
358 used). Additionally, non-complex small annotations
359 require no additional memory management (\c new /
362 \idea Pool the annotation vectors: In the destructor
363 swap the vector into a vector graveyard (swapping
364 two vectors is an O(1) no allocation operation). In
365 the constructor, if there is a vector in the
366 graveyard, swap it in from there. Of course, it
367 would be better to do away with the vector and just
368 allocate the space together with the packet but
369 that looks quite complicated to do ... especially
370 considering that the packetimpl itself uses a pool.
375 ///\name Other methods
378 bool operator==(Packet other) const; ///< Check for packet identity
379 /**< Two packet handles compare equal if they really are the
380 same packet header in the same packet chain. */
381 bool boolean_test() const; ///< Check, whether the packet is valid()
383 bool valid() const; ///< Check, whether the packet is valid()
384 /**< An in - valid() packet does not allow any operation
385 except checking for validity and assignment. in -
386 valid() packets serve the same role as 0-pointers.
388 This is an alias for boolean_test() which is called
389 when using a packet in a boolean context. */
391 void finalizeThis(); ///< Update calculated fields
392 /**< The finalize() fammily of members will update
393 calculated packet fields: checksums, size fields and so
394 on. This includes any field, which can be set from
395 other information in the packet. Each concrete packet
396 type should document, which fields are set by
399 finalizeThis() will \e only process the current
400 header. Even if only changing fields in this protocol,
401 depending on the protocol it may not be enough to
402 finalize this header only. See the packet type
405 template <class Other>
406 void finalizeTo(); ///< Update calculated fields
407 /**< The finalize() fammily of members will update
408 calculated packet fields: checksums, size fields and so
409 on. This includes any field, which can be set from
410 other information in the packet. Each concrete packet
411 type should document, which fields are set by
414 finalizeTo() will automatically process all
415 packets/headers/interpreters from the \e first
416 occurrence of packet type \a Other (beginning at \c
417 this packet searching forward towards deeper nested
418 packets) backwards up to \c this.
420 This call is equivalent to
422 p.finalizeTo(p.next<Other>())
425 void finalizeTo(Packet other); ///< Update calculated fields
426 /**< The finalize() fammily of members will update
427 calculated packet fields: checksums, size fields and so
428 on. This includes any field, which can be set from
429 other information in the packet. Each concrete packet
430 type should document, which fields are set by
433 finalizeTo(other) will automatically process all
434 packets/headers/interpreters beginning at \a other
435 backwards towards outer packets up to \c this. */
437 void finalizeAll(); ///< Update calculated fields
438 /**< The finalize() fammily of members will update
439 calculated packet fields: checksums, size fields and so
440 on. This includes any field, which can be set from
441 other information in the packet. Each concrete packet
442 type should document, which fields are set by
445 finalizeAll() will automatically process all
446 packets/headers/interpreters from the end of the chain
447 (the most inner packet) backwards up to \c this.
449 This call is equivalent to
451 p.finalizeTo(p.last())
454 Beware, that finalizeAll() will \e not finalize any
455 headers before \c this, it will \e only process inner
458 void dump(std::ostream & os) const; ///< Write out a printable packet representation
459 /**< This method is provided mostly to help debugging packet
460 problems. Each concrete packet should implement a dump
461 method writing out all fields of the packet in a
462 readable representation. dump() will call this member
463 for each packet/header/interpreter in the chain from \c
464 this packet up to the end of the chain. */
466 TypeIdValue typeId() const; ///< Get id of \c this packet
467 /**< This value is used e.g. in the packet registry to
468 associate packet types with other information.
469 \returns A type holding the same information as a
470 type_info object, albeit assignable */
471 factory_t factory() const; ///< Return factory instance of \c this packet
472 /**< The returned factory instance can be used to create new
473 packets of the given type without knowing the concrete
474 type of the packet. The value may be stored away for
475 later use if needed. */
480 explicit Packet(PacketInterpreterBase::ptr packet);
482 PacketInterpreterBase::ptr ptr() const;
485 Packet checkNext() const;
486 Packet checkLast() const;
488 PacketInterpreterBase::ptr packet_;
490 template <class PacketType>
491 friend class ConcretePacket;
492 friend class PacketParserBase;
495 /** \brief Protocol specific packet handle
497 The ConcretePacket template class extends Packet to provide protocol/packet type specific
498 aspects. These are packet constructors and access to the parsed packet fields.
500 The \c PacketType template argument to ConcretePacket is a protocol specific and internal
501 policy class which defines the protocol specific behavior. To access a specific type of
502 packet, the library provides corresponding typedefs of ConcretePacket < \a SomePacketType >
503 (e.g. \ref EthernetPacket as typedef for \ref ConcretePacket < \ref EthernetPacketType >).
505 The new members provided by ConcretePacket over packet are mostly comprised of the packet
506 constructors. These come in three major flavors:
508 \li The create() family of constructors will create completely new packets.
509 \li The createAfter() family of constructors will create new packets (with new data for the
510 packet) \e after a given existing packet.
511 \li The createBefore() family of constructors will create new packets (again with new data)
512 \e before a given existing packet.
514 Whereas create() will create a completely new packet with it's own chain and data storage,
515 createAfter() and createBefore() extend a packet with additional
516 headers/interpreters. createAfter() will set the payload of the given packet to the new
517 packet whereas createBefore() will create a new packet with the existing packet as it's
520 createAfter() differs from Packet::parseNextAs() in that the former creates a new packet \e
521 replacing any possibly existing data whereas the latter will interpret the already \e
522 existing data as given by the type argument.
524 \see \ref PacketTypeBase for a specification of the interface to be provided by the \a
525 PacketType policy class.
527 template <class PacketType>
532 ///////////////////////////////////////////////////////////////////////////
535 typedef PacketType type;
536 typedef typename PacketType::parser Parser;
538 ///////////////////////////////////////////////////////////////////////////
539 ///\name Structors and default members
542 // default copy constructor
543 // default copy assignment
544 // default destructor
545 // no conversion constructors
547 ConcretePacket(); ///< Create uninitialized packet handle
548 /**< An uninitialized handle is not valid(). It does not
549 allow any operation except assignment and checking for
552 static factory_t factory(); ///< Return factory for packets of specific type
553 /**< This \e static member is like Packet::factory() for a
554 specific packet of type \a PacketType */
556 // Create completely new packet
558 static ConcretePacket create(); ///< Create default initialized packet
559 /**< The packet will be initialized to it's default empty
561 static ConcretePacket create(senf::NoInit_t); ///< Create uninitialized empty packet
562 /**< This will create a completely empty and uninitialized
563 packet with <tt>size() == 0</tt>.
564 \param[in] senf::noinit This parameter must always have the
565 value \c senf::noinit. */
566 static ConcretePacket create(size_type size); ///< Create default initialized packet
567 /**< This member will create a default initialized packet
568 with the given size. If the size parameter is smaller
569 than the minimum allowed packet size an exception will
571 \param[in] size Size of the packet to create in bytes.
572 \throws TruncatedPacketException if \a size is smaller
573 than the smallest permissible size for this type of
575 static ConcretePacket create(size_type size, senf::NoInit_t);
576 ///< Create uninitialized packet
577 /**< Creates an uninitialized (all-zero) packet of the exact
579 \param[in] size Size of the packet to create in bytes
580 \param[in] senf::noinit This parameter must always have the
581 value \c senf::noinit. */
583 template <class ForwardReadableRange>
584 static ConcretePacket create(
585 ForwardReadableRange const & range,
586 typename boost::disable_if< boost::is_integral<ForwardReadableRange> >::type * = 0);
588 template <class ForwardReadableRange>
589 static ConcretePacket create(ForwardReadableRange const & range);
590 ///< Create packet from given data
591 /**< The packet will be created from a copy of the given
592 data. The data from the range will be copied directly
593 into the packet representation. The data will \e not be
594 validated in any way.
596 href="http://www.boost.org/libs/range/index.html">Boost.Range</a>
597 of data to construct packet from. */
600 // Create packet as new packet after a given packet
602 static ConcretePacket createAfter(Packet packet);
603 ///< Create default initialized packet after \a packet
604 /**< The packet will be initialized to it's default empty
605 state. It will be appended as next header/interpreter
606 after \a packet in that packets interpreter chain.
607 \param[in] packet Packet to append new packet to. */
608 static ConcretePacket createAfter(Packet packet, senf::NoInit_t);
609 ///< Create uninitialized empty packet after\a packet
610 /**< This will create a completely empty and uninitialized
611 packet with <tt>size() == 0</tt>. It will be appended
612 as next header/interpreter after \a packet in that
613 packets interpreter chain.
614 \param[in] packet Packet to append new packet to.
615 \param[in] senf::noinit This parameter must always have the
616 value \c senf::noinit. */
617 static ConcretePacket createAfter(Packet packet, size_type size);
618 ///< Create default initialized packet after \a packet
619 /**< This member will create a default initialized packet
620 with the given size. If the size parameter is smaller
621 than the minimum allowed packet size an exception will
622 be thrown. It will be appended as next
623 header/interpreter after \a packet in that packets
625 \param[in] packet Packet to append new packet to.
626 \param[in] size Size of the packet to create in bytes.
627 \throws TruncatedPacketException if \a size is smaller
628 than the smallest permissible size for this type of
630 static ConcretePacket createAfter(Packet packet, size_type size, senf::NoInit_t);
631 ///< Create uninitialized packet after \a packet
632 /**< Creates an uninitialized (all-zero) packet of the exact
633 given size. It will be appended as next
634 header/interpreter after \a packet in that packets
636 \param[in] packet Packet to append new packet to.
637 \param[in] size Size of the packet to create in bytes
638 \param[in] senf::noinit This parameter must always have the
639 value \c senf::noinit. */
641 template <class ForwardReadableRange>
642 static ConcretePacket createAfter(
644 ForwardReadableRange const & range,
645 typename boost::disable_if< boost::is_integral<ForwardReadableRange> >::type * = 0);
647 template <class ForwardReadableRange>
648 static ConcretePacket createAfter(Packet packet,
649 ForwardReadableRange const & range);
650 ///< Create packet from given data after \a packet
651 /**< The packet will be created from a copy of the given
652 data. The data from the range will be copied directly
653 into the packet representation. The data will \e not be
654 validated in any way. It will be appended as next
655 header/interpreter after \a packet in that packets
657 \param[in] packet Packet to append new packet to.
659 href="http://www.boost.org/libs/range/index.html">Boost.Range</a>
660 of data to construct packet from. */
663 // Create packet as new packet (header) before a given packet
665 static ConcretePacket createBefore(Packet packet);
666 ///< Create default initialized packet before \a packet
667 /**< The packet will be initialized to it's default empty
668 state. It will be prepended as previous
669 header/interpreter before \a packet in that packets
671 \param[in] packet Packet to prepend new packet to. */
672 static ConcretePacket createBefore(Packet packet, senf::NoInit_t);
673 ///< Create uninitialized empty packet before \a packet
674 /**< Creates a completely empty and uninitialized packet. It
675 will be prepended as previous header/interpreter before
676 \a packet in that packets interpreter chain.
677 \param[in] packet Packet to prepend new packet to. */
679 // Create a clone of the current packet
681 ConcretePacket clone() const;
684 ///////////////////////////////////////////////////////////////////////////
688 Parser * operator->() const; ///< Access packet fields
689 /**< This operator allows to access the parsed fields of the
690 packet using the notation <tt>packet->field()</tt>. The
691 fields of the packet are specified by the PacketType's
694 The members are not strictly restricted to simple field
695 access. The parser class may have any member which is
696 needed for full packet access (e.g. checksum validation
698 \see \ref packetparser for the parser interface. */
700 Parser parser() const; ///< Access packet field parser directly
701 /**< Access the parser of the packet. This is the same
702 object returned by the operator->() operator. The
703 operator however does not allow to access this object
704 itself, only it's members.
705 \see \ref packetparser for the parser interface */
710 typedef PacketInterpreter<PacketType> interpreter;
712 ConcretePacket(typename interpreter::ptr packet_);
714 typename interpreter::ptr ptr() const;
717 friend class PacketInterpreter<PacketType>;
724 ///////////////////////////////hh.e////////////////////////////////////////
726 #if !defined(HH_Packets__decls_) && !defined(HH_Packet_i_)
728 #include "Packet.cci"
730 #include "Packet.cti"
737 // c-file-style: "senf"
738 // indent-tabs-mode: nil
739 // ispell-local-dictionary: "american"
740 // compile-command: "scons -u test"
741 // comment-column: 40