Source: ../../libxipc/finder_msg.hh
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// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// Copyright (c) 2001-2003 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/libxipc/finder_msg.hh,v 1.3 2003/03/10 23:20:23 hodson Exp $
#ifndef __IPC_FINDER_MSG_HH__
#define __IPC_FINDER_MSG_HH__
#include <list>
#include <string>
#include "libxorp/xorp.h"
#include "libxorp/exceptions.hh"
#include "libxorp/callback.hh"
#include "hmac.hh"
/**
* @short Base class for Finder Protocol messages.
*
* Provides the functionality common to all message types: sequencing,
* source identifier, authentication, and rendering.
*/
struct FinderMessage {
FinderMessage(uint32_t src, uint32_t seq, const string& name)
: _src(src), _seq(seq), _name(name) {}
virtual ~FinderMessage() {}
typedef ref_ptr<FinderMessage> RefPtr;
/**
* Create a string containing ascii packet data.
*/
const string render() const;
/**
* Create a string containing ascii packet data that includes an
* authentication header.
*
* @param h header authentication object.
*/
const string render_signed(const HMAC& h) const;
/**
* @return source identifier of message.
*/
inline uint32_t srcid() const { return _src; }
/**
* @return sequence number of message.
*/
inline uint32_t seqno() const { return _seq; }
/**
* set sequence number of message.
*/
inline void set_seqno(uint32_t s) { _seq = s; }
/**
* @return message name (i.e. 'hello', 'bye')
*/
inline const string& name() const { return _name; }
protected:
/**
* @return HMAC signature of message header.
*/
const string render_signature(const HMAC& h, const string& msg_header)
const;
/**
* @return Ascii representation of header.
*/
const string render_header(size_t payload_bytes) const;
/**
* FinderMessage sub-classes must implement this method.
*
* @return Ascii representation of data associated with packet.
*/
virtual const string render_payload() const = 0;
protected:
uint32_t _src;
uint32_t _seq;
string _name;
};
/**
* Exception class thrown by FinderMessage parsing routines when
* things go wrong.
*/
class BadFinderMessage : public XorpException {
public:
BadFinderMessage(const char* file, size_t line, const string& why)
: XorpException("BadFinderMessage", file, line), _why(why) {}
const string why() const {
return (_why.empty()) ? string("Not Specified") : _why;
}
protected:
const string _why;
};
/**
* FinderParselet is the base class for mini-parsers that handle the
* payload data of Finder messages. They parse the payload of the
* particular message type they understand and then call a user
* specified callback.
*/
struct FinderParselet {
/**
* Construct a payload parser.
* @param name the message type understood by the parser.
*/
FinderParselet(const string& name) : _name(name) {}
virtual ~FinderParselet() {}
/**
* Parse payload of message.
*
* @param src Source identifier taken from common message header.
* @param seq Sequence number taken from common message header.
* @param b Buffer that contains data to be parsed.
* @param bpos position that payload parsing should be commenced from.
* This value should be updated to point to the last character parsed.
*/
virtual void parse(uint32_t src, uint32_t seq, const string& b,
string::const_iterator& bpos) const
throw (BadFinderMessage) = 0;
/**
* @return name of message type understood by parselet.
*/
const string name() const { return _name; }
protected:
string _name;
};
/**
* Parser of finder messages. Parses common header and passes payload
* data to registered ParsingElements that invoke user callbacks when
* packets of given type arrive.
*
* Sub-parsers are added with the @ref add method.
* add takes a ParsingElement as an argument. These are
* created by helper functions like hello_notifier, eg:
*
<pre>
void hello_handler(const FinderHello& msg) {
... do something with hello message
}
FinderParser fp;
fp.add(hello_notifier(callback(hello_handler)));
</pre>
*/
struct FinderParser {
typedef ref_ptr<const FinderParselet> ParsingElement;
typedef list<ParsingElement> PEList;
/**
* Attempts to determine if the supplied string looks like a
* FinderMessage header.
* @param header candidate finder message header.
* @returns header size if valid, 0 if there is no enough data to
* determine if it is a valid header. Throws an exception is data
* does not look like a FinderMessage header.
*/
static ssize_t peek_header_bytes(const string& header)
throw (BadFinderMessage);
/**
* @return maximum header size (actually size can be certain not
* a valid header).
*/
static size_t max_header_bytes();
/**
* @returns the size of the payload data.
*/
static size_t peek_payload_bytes(const string& header)
throw (BadFinderMessage);
/**
* Parses message and calls callbacks if message type has a
* registered notifier.
*
* @param buf buffer to be parsed.
* @param buf_pos starting position of parsing. Updated to point to
* end of parsing upon return.
*/
inline size_t
parse(const string& buf, string::const_iterator& buf_pos) const
throw (BadFinderMessage) {
return parse(0, buf, buf_pos);
}
/**
* Parses a message using HMAC and calls callbacks if message type
* has a registered notifier.
*
* @param h HMAC instance to be used to check header authentication.
* @param buf buffer to be parsed.
* @param buf_pos starting position of parsing. Updated to point
* to end of parsing upon return.
*/
inline size_t
parse_signed(const HMAC& h, const string& buf,
string::const_iterator& buf_pos) const
throw (BadFinderMessage) {
return parse(&h, buf, buf_pos);
}
/**
* Parses a message using HMAC and calls callbacks if message type
* has a registered notifier.
*
* @param h pointer to HMAC to be used to check header authentication.
* @param buf buffer to be parsed.
* @param buf_pos starting position of parsing. Updated to point
* to end of parsing upon return.
*/
size_t parse(const HMAC* h, const string& b, string::const_iterator& bp)
const throw (BadFinderMessage);
/**
* Add user callback for a particular message type. Used in
* conjunction with ParsingElement generating functions (ie
* @ref notifier and it similarly named brethren).
*/
bool add(const ParsingElement& pe);
protected:
static bool parse_header(string::const_iterator& buffer_pos,
uint32_t& major,
uint32_t& minor,
uint32_t& src,
uint32_t& seq,
uint32_t& payload_bytes,
string& msgname);
bool parse_payload(uint32_t src,
uint32_t seq,
const string& msgname,
const string& buf,
string::const_iterator& buf_pos) const;
inline bool parse_signature(const HMAC* h,
const string& header,
const string& b,
string::const_iterator& bp) const;
PEList _parsers;
};
// ----------------------------------------------------------------------------
/**
* HELLO message.
*/
struct FinderHello : public FinderMessage {
FinderHello(uint32_t src, uint32_t seq) : FinderMessage(src, seq, "hello") {}
const string render_payload() const;
};
/**
* HELLO message parser.
*/
struct FinderHelloParser : public FinderParselet {
typedef XorpCallback1<void, const FinderHello&>::RefPtr Callback;
FinderHelloParser(const Callback& cb)
: FinderParselet("hello"), _cb(cb) {}
void parse(uint32_t src, uint32_t seq,
const string&, string::const_iterator&) const
throw (BadFinderMessage);
protected:
Callback _cb;
};
/**
* ParsingElement generating function to hook user callbacks when
* HELLO messages are received. Used in conjunction with
* @ref FinderParser::add.
*/
inline FinderParser::ParsingElement
hello_notifier(const FinderHelloParser::Callback& cb)
{
return FinderParser::ParsingElement(new FinderHelloParser(cb));
}
// ----------------------------------------------------------------------------
/**
* BYE Mesasge.
*/
struct FinderBye : public FinderMessage {
FinderBye(uint32_t src, uint32_t seq) : FinderMessage(src, seq, "bye") {}
const string render_payload() const;
};
/**
* BYE Message Parser.
*/
struct FinderByeParser : public FinderParselet {
typedef XorpCallback1<void, const FinderBye&>::RefPtr Callback;
FinderByeParser(const Callback& cb)
: FinderParselet("bye"), _cb(cb) {}
void parse(uint32_t src, uint32_t seq,
const string&, string::const_iterator&) const
throw (BadFinderMessage);
protected:
Callback _cb;
};
/**
* ParsingElement generating function to hook user callbacks when
* BYE messages are received. Used in conjunction with
* @ref FinderParser::add.
*/
inline FinderParser::ParsingElement
bye_notifier(const FinderByeParser::Callback& cb)
{
return FinderParser::ParsingElement(new FinderByeParser(cb));
}
// ----------------------------------------------------------------------------
/**
* ACK Mesasge.
*/
struct FinderAck : public FinderMessage {
FinderAck(uint32_t src, uint32_t seq, uint32_t acking_no)
: FinderMessage(src, seq, "ack"), _ack(acking_no) {}
const string render_payload() const;
protected:
uint32_t _ack;
};
/**
* ACK Message Parser.
*/
struct FinderAckParser : public FinderParselet {
typedef XorpCallback1<void, const FinderAck&>::RefPtr Callback;
FinderAckParser(const Callback& cb) : FinderParselet("ack"), _cb(cb) {}
void parse(uint32_t src, uint32_t seq,
const string& buf, string::const_iterator& buf_pos) const
throw (BadFinderMessage);
protected:
Callback _cb;
};
/**
* ParsingElement generating function to hook user callbacks when
* ACK messages are received. Used in conjunction with
* @ref FinderParser::add.
*/
inline FinderParser::ParsingElement
ack_notifier(const FinderAckParser::Callback& cb)
{
return FinderParser::ParsingElement(new FinderAckParser(cb));
}
// ----------------------------------------------------------------------------
/**
* ASSOCIATE Mesasge.
*/
struct FinderAssociate : public FinderMessage {
FinderAssociate(uint32_t src,
uint32_t seq,
const string& t_and_m, // target and method
const string& a) // associated value
: FinderMessage(src, seq, "associate"), _t_and_m(t_and_m), _a(a) {}
const string render_payload() const;
protected:
const string _t_and_m;
const string _a;
};
/**
* ASSOCIATE Message Parser.
*/
struct FinderAssociateParser : public FinderParselet {
typedef XorpCallback1<void, const FinderAssociate&>::RefPtr Callback;
FinderAssociateParser(const Callback& cb)
: FinderParselet("associate"), _cb(cb) {}
void parse(uint32_t src, uint32_t seqno,
const string&, string::const_iterator&) const
throw (BadFinderMessage);
protected:
Callback _cb;
};
/**
* ParsingElement generating function to hook user callbacks when
* ASSOCIATE messages are received. Used in conjunction with
* @ref FinderParser::add.
*/
inline FinderParser::ParsingElement
associate_notifier(const FinderAssociateParser::Callback& cb)
{
return FinderParser::ParsingElement(new FinderAssociateParser(cb));
}
// ----------------------------------------------------------------------------
/**
* QUESTION Mesasge.
*/
struct FinderQuestion : public FinderMessage {
FinderQuestion(uint32_t src, uint32_t seq, const string& target_and_method) :
FinderMessage(src, seq, "question"), _t_m(target_and_method) {}
const string render_payload() const;
protected:
const string _t_m;
};
/**
* QUESTION Message Parser.
*/
struct FinderQuestionParser : FinderParselet {
typedef XorpCallback1<void, const FinderQuestion&>::RefPtr Callback;
FinderQuestionParser(const Callback& cb)
: FinderParselet("question"), _cb(cb) {}
void parse(uint32_t src, uint32_t seqno,
const string& buf, string::const_iterator& buf_pos) const
throw (BadFinderMessage);
protected:
Callback _cb;
};
/**
* ParsingElement generating function to hook user callbacks when
* QUESTION messages are received. Used in conjunction with
* @ref FinderParser::add.
*/
inline FinderParser::ParsingElement
question_notifier(const FinderQuestionParser::Callback& cb)
{
return FinderParser::ParsingElement(new FinderQuestionParser(cb));
}
// ----------------------------------------------------------------------------
/**
* ANSWER Mesasge.
*/
struct FinderAnswer : public FinderMessage {
FinderAnswer(uint32_t src, uint32_t seq, const string& target_and_method) :
FinderMessage(src, seq, "answer"), _t_m(target_and_method) {}
protected:
const string _t_m;
};
/**
* ANSWER Message Parser.
*/
struct FinderAnswerParser : FinderParselet {
typedef XorpCallback1<void, const FinderAnswer&>::RefPtr Callback;
FinderAnswerParser(const Callback& cb)
: FinderParselet("answer"), _cb(cb) {}
void parse(uint32_t src, uint32_t seqno,
const string& buf, string::const_iterator& buf_pos) const
throw (BadFinderMessage);
protected:
Callback _cb;
};
/**
* ParsingElement generating function to hook user callbacks when
* ANSWER messages are received. Used in conjunction with
* @ref FinderParser::add.
*/
inline FinderParser::ParsingElement
answer_notifier(const FinderAnswerParser::Callback& cb)
{
return FinderParser::ParsingElement(new FinderAnswerParser(cb));
}
#endif // __IPC_FINDER_MSG_HH__
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