% run this through LaTeX with the appropriate wrapper \ifpractical \dotopic{BUILDING AN OSI APPLICATION} \else \dotopic{IMPLEMENTING NEW SERVICES} \fi \begin{bwslide} \part* {OUTLINE}\bf \begin{description} \item[PART I:] A MODEL FOR DISTRIBUTED APPLICATIONS \item[PART II:] THE RO-NOTATION \item[PART III:] STATIC FACILITIES \item[PART IV:] DYNAMIC FACILITIES \ifpractical \item[PART V:] EXTRA FOR EXPERTS! \fi \end{description} \end{bwslide} \begin{bwslide} \ctitle {A BIG ACKNOWLEDGEMENT} \begin{nrtc} \item THIS PART OF THE TALK IS BASED ON AN EARLIER PRESENTATION \begin{quote} BUILDING DISTRIBUTION APPLICATIONS IN AN OSI FRAMEWORK \end{quote} \item WHICH RECEIVED REVIEW FROM A LOT OF INDIVIDUALS \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {INTRODUCTION} \begin{nrtc} \item LOOSELY COUPLED SYSTEMS THAT ARE BUILT USING REMOTE PROCEDURE CALLS (RPC) ARE GAINING POPULARITY, e.g., NFS \item THE OSI REMOTE OPERATIONS CONCEPT IS INTENDED TO PROVIDE THIS FUNCTIONALITY FOR: \begin{nrtc} \item MESSAGING \item DIRECTORY SERVICES \item NETWORK MANAGEMENT \item REMOTE DATABASE ACCESS \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {MOTIVATION} \begin{nrtc} \item MANY FEEL THAT THIS CAPABILITY MAY BE A KEY FACTOR IN THE OVERALL SUCCESS OF OSI STANDARDIZATION \item BUT, REMOTE OPERATIONS ARE SUFFICIENTLY GENERAL TO REQUIRE ADDITIONAL DISCIPLINE, BEYOND THE OSI STANDARDS, FOR THEIR USE AS AN RPC MECHANISM \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {THE APPLICATIONS COOKBOOK} \begin{nrtc} \item THE SET OF RULES AND LOCAL IMPLEMENTATION DECISIONS PLACED ON REMOTE OPERATIONS TO MAKE THE PROBLEM MANAGEABLE: \begin{nrtc} \item LANGUAGE BINDINGS (``C'') \item TOOLS FOR AUTOMATICALLY GENERATING PARTS OF THE PROGRAMS WHICH USE REMOTE OPERATIONS \item A RUN-TIME ENVIRONMENT AND SOME BOILERPLATE \item CONVENTIONS FOR NAMING AND ADDRESSING SERVICES AND ENTITIES \end{nrtc} \item A (SMALL) PART OF THE ISODE \begin{nrtc} \item VOLUME 4 OF THE USER'S MANUAL \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {FOREWORD} \begin{quote}\em ``$\ldots$ The term `holistic' refers to my conviction that what we are concerned with here is the fundamental interconnectedness of all things. I do not concern myself with such petty things as fingerprint powder, telltale pieces of pocket fluff and inane footprints. I see the solution to each problem as being detectable in the pattern and web of the whole. The connections between causes and effects are often much more subtle and complex than we with our rough and ready understanding of the physical world might naturally suppose, Mrs.~Rawlinson. ``Let me give you an example. If you go to an acupuncturist with a toothache he sticks a needle instead into your thigh. Do you know why he does that, Mrs.~Rawlinson? ``No, neither do I, Mrs.~Rawlinson, but we intend to find out$\ldots$'' \end{quote} \raggedright ---DOUGLAS ADAMS, \em Dirk Gently's Holistic Detective Agency (1987) \end{bwslide} \begin{bwslide} \part {A MODEL FOR DISTRIBUTED APPLICATIONS}\bf \begin{nrtc} \item ABSTRACT DATA TYPES \item OPERATIONS \item RELIABILITY CHARACTERISTICS \item IN PERSPECTIVE \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {USE OF REMOTE OPERATIONS IN OSI} \begin{nrtc} \item {}[ECMA~TR/31] PRESENTS A METHOD FOR USING REMOTE OPERATIONS TO: \begin{nrtc} \item SPECIFY THE EXTERNALLY VISIBLE CHARACTERISTICS NEEDED FOR INTERCONNECTION \item WHILE AVOIDING UNNECESSARY CONSTRAINTS UPON THE INTERNAL DESIGN OF THE SYSTEMS TO BE INTERCONNECTED \end{nrtc} \item ALTHOUGH THE LATTER HALF OF THIS DOCUMENT (THE PROTOCOL) IS NOW OBSOLETE, THE FIRST FOUR SECTIONS (THE METHOD) ARE QUITE RELEVANT \item {}[ECMA~TR/31] IS BASED ON [X.410], WE TERM THIS ``OLD-STYLE'' ROS \item {}[ISO~9072] IS THE NEWER JOINT ISO/CCITT WORK, WE TERM THIS ``NEW-STYLE'' ROS \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {A BIT OF HISTORY} \begin{nrtc} \item XEROX's COURIER WAS THE FIRST WELL-KNOWN SYSTEM TO USE THIS APPROACH \item BUT EVEN IN THE EARLY 70's, SIMILAR IDEAS WERE BEING EXPLORED ELSEWHERE (e.g., MIT) \item TODAY, ONC (SUN's RPC) AND DECORUM (APOLLO's NCS) ARE CONTINUING IN THIS VEIN \end{nrtc} \end{bwslide} \begin{bwslide} \part* {ABSTRACT DATA TYPES}\bf \begin{nrtc} \item REMOTE OPERATIONS ARE A MECHANISM BY WHICH LOOSELY COUPLED SYSTEMS INTERACT \item BUT, REMOTE OPERATIONS ARE ONLY ONE PART OF A LARGER PICTURE HOWEVER \item THE FUNDAMENTAL CONCEPT IS THAT OF THE \emph{ABSTRACT DATA TYPE} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {ABSTRACT DATA TYPES} \begin{nrtc} \item PUT SIMPLY, AN ABSTRACT DATA TYPE DEFINES BOTH \begin{nrtc} \item THE DATA STRUCTURE CONTAINED IN AN OBJECT (SYNTAX), AND \item HOW THAT DATA IS INTERPRETED (SEMANTICS) \end{nrtc} \item THIS IS HARDLY A NEW CONCEPT \begin{nrtc} \item e.g., SMALLTALK, SIMULA, and so on \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PROPERTIES OF ABSTRACT DATA TYPES:\\ REPRESENTATION} \begin{nrtc} \item DATA STRUCTURES IN PROGRAMMING LANGUAGES HAVE A \emph{CONCRETE} REPRESENTATION \begin{nrtc} \item WHICH IS DEFINED BY THE PROGRAMMING LANGUAGE AND THE UNDERLYING HARDWARE \item e.g., BYTE-ORDERING, WORD SIZE, etc. \end{nrtc} \item THE CORRESPONDING ABSTRACT DATA TYPE IS DEFINED IN AN IMPLEMENTATION-INDEPENDENT FASHION \begin{nrtc} \item TERMED THE \emph{ABSTRACT SYNTAX} \end{nrtc} \item AN APPLICATION CAN EXPECT THIS TO BEHAVE CONSISTENTLY REGARDLESS OF THE HARDWARE ON WHICH IT IS RUNNING \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {REPRESENTATION: EXAMPLE\\ ABSTRACT SYNTAX} \vskip.15in \begin{verbatim} Mail-Address ::= SEQUENCE { local GraphicString, domain GraphicString, options BITSTRING { default-local(0), default-host(1) } DEFAULT { default-local, default-host } } \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {REPRESENTATION: EXAMPLE\\ CONCRETE SYNTAX} \vskip.15in \begin{verbatim} struct mail_address { char *local; char *domain; unsigned char options; #define default_local 0x01 #define default_host 0x02 }; \end{verbatim} \begin{nrtc} \item PLUS HARDWARE, COMPILER, etc. \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PROPERTIES OF ABSTRACT DATA TYPES:\\ SERIALIZATION} \begin{nrtc} \item ABSTRACT TRANSFER NOTATION: \begin{nrtc} \item A WELL-DEFINED SET OF RULES USED TO DEFINE HOW ABSTRACT DATA TYPES ARE TRANSMITTED THROUGH THE NETWORK \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {SERIALIZATION (cont.)} \begin{nrtc} \item CONCEPTUALLY, TWO MAPPINGS OCCUR \item FIRST, THE DATA STRUCTURE IS MAPPED TO THE ABSTRACT SYNTAX FOR ITS CORRESPONDING ABSTRACT DATA TYPE \begin{nrtc} \item THIS IS A LOCAL ISSUE \end{nrtc} \item SECOND, THE ABSTRACT SYNTAX IS MAPPED TO THE TRANSFER SYNTAX, A STREAM OF OCTETS \begin{nrtc} \item THE ABSTRACT TRANSFER NOTATION IS USUALLY THE BASIC ENCODING RULES \item OTHER POSSIBILITIES INCLUDE COMPRESSION, ENCRYPTION, etc. \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PROPERTIES OF ABSTRACT DATA TYPES:\\ OPERATIONS} \begin{nrtc} \item ACCESS TO AN ABSTRACT DATA TYPE IS DEFINED BY A SET OF PRIMITIVE ACTIONS \item EACH PRIMITIVE ACTION IS TERMED AN \emph{OPERATION} \item THIS SET OF OPERATIONS DEFINES THE COMPLETE BEHAVIOR OF AN ABSTRACT DATA TYPE \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {OBJECT MODEL} \begin{nrtc} \item SINCE OPERATIONS INTRODUCE A LEVEL OF INDIRECTION, USING ABSTRACT DATA TYPES RATHER THAN CONCRETE DATA STUCTURES PERMITS ACCESS TO DATA STRUCTURES WITHOUT REGARD TO THEIR ACTUAL IMPLEMENTATION \item OPERATIONS ARE SAID TO BE \emph{TOTAL}, AS THE NORMAL OUTCOME (RESULT), AND THE EXCEPTION OUTCOMES (THE ERRORS) ARE WELL-DEFINED AND UNAMBIGUOUS \end{nrtc} \end{bwslide} \begin{bwslide} \part* {OPERATIONS}\bf \begin{nrtc} \item IN ITS PRIMITIVE FORM, AN \emph{OPERATION} IS A SIMPLE REQUEST/REPLY INTERACTION \item A \emph{INVOCATION} GENERATES ONE OF THREE OUTCOMES: \begin{nrtc} \item A \emph{RESULT}, IF THE OPERATION SUCCEEDS; \item AN \emph{ERROR}, IF THE OPERATION FAILED; or, \item A \emph{REJECTION}, IF THE OPERATION WAS NOT PERFORMED \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {NOTE DIFFERENCE BETWEEN} \begin{nrtc} \item SERVICES: \begin{nrtc} \item CONSUMER/PROVIDER \end{nrtc} \item OPERATIONS: \begin{nrtc} \item INVOKER/PERFORMER \end{nrtc} \item ASSOCIATIONS: \begin{nrtc} \item INITIATOR/RESPONDER \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PROPERTIES OF OPERATIONS:\\ INVOCATIONS} \begin{nrtc} \item THE OPERATION IS \emph{INVOKED} WHEN IT IS REQUESTED \item AN INVOCATION CONSISTS OF: \begin{nrtc} \item AN \emph{OPERATION NUMBER} IDENTIFYING THE OPERATION REQUESTED \item AN ARBITRARILY COMPLEX \emph{ARGUMENT} \item AN \emph{INVOCATION IDENTIFIER} DISTINGUISHING THIS INVOCATION FROM PREVIOUS INVOCATIONS \item (POSSIBLY) A \emph{LINKED-INVOCATION IDENTIFIER} \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {LINKED INVOCATIONS} \begin{nrtc} \item INTRODUCED IN THE NEWER JOINT ISO/CCITT WORK \item SOMETIMES REFERRED TO AS A ``CALLBACK'' OR A ``REMOTE UPCALL'' \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {ONE USE OF LINKED INVOCATIONS} \begin{nrtc} \item SUPPOSE YOU WANT AN OPERATION THAT RETURNS MULTIPLE RESULTS \item DEFINE THE OPERATION TO HAVE A LINKED OPERATION WITH \begin{nrtc} \item ARGUMENT: A PARTIAL RESULT \end{nrtc} \item HERE'S HOW IT WORKS: \begin{nrtc} \item CONSUMER INVOKES OPERATION \item AS EACH PARTIAL RESULT IS COMPUTED,\\ PROVIDER INVOKES LINKED OPERATION \item WHEN LAST PARTIAL RESULT READY,\\ PROVIDER RETURNS THIS AS A RESULT \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PROPERTIES OF OPERATIONS:\\ RESULTS} \begin{nrtc} \item IF THE OPERATION SUCCEEDS, THEN A RESULT IS RETURNED \item A RESULT CONSISTS OF: \begin{nrtc} \item AN INVOCATION IDENTIFIER CORRESPONDING TO THE OPERATION WHICH SUCCEEDED \item (POSSIBLY) AN ARBITRARILY COMPLEX \emph{RESULT} \end{nrtc} \item ACTUALLY, A RESULT MAY BE \emph{OPTIONALLY} RETURNED ON SUCCESS \begin{nrtc} \item (A BAD IDEA) \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PROPERTIES OF OPERATIONS:\\ ERRORS} \begin{nrtc} \item IF THE OPERATION FAILS, THEN AN ERROR IS RETURNED \item AN ERROR CONSISTS OF: \begin{nrtc} \item AN INVOCATION IDENTIFIER CORRESPONDING TO THE OPERATION WHICH FAILED \item AN \emph{ERROR NUMBER} IDENTIFYING THE ERROR ENCOUNTERED \item (POSSIBLY) AN ARBITRARILY COMPLEX \emph{PARAMETER} \end{nrtc} \item NOTE THAT ERRORS DO NOT NECESSARILY INDICATE BAD BEHAVIOR! \begin{nrtc} \item THEY CAN OCCUR AS A PART OF CORRECT AND NORMAL OPERATIONS \item HENCE, THINK OF THEM AS EXCEPTIONS \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PROPERTIES OF OPERATIONS:\\ REJECTIONS} \begin{nrtc} \item IF THE OPERATION CAN NOT BE PERFORMED, THEN A REJECTION IS RETURNED \item A REJECTION CONSISTS OF: \begin{nrtc} \item AN INVOCATION IDENTIFIER CORRESPONDING TO THE OPERATION WHICH WAS REJECTED \item A \emph{REASON} EXPLAINING WHY THE OPERATION WAS REJECTED \begin{nrtc} \item e.g., MISTYPED PARAMETERS \end{nrtc} \end{nrtc} \item SOME REJECTIONS ARE USER-INITIATED, OTHERS ARE PROVIDER-INITIATED \end{nrtc} \end{bwslide} \begin{bwslide} \part* {RELIABILITY CHARACTERISTICS}\bf \begin{nrtc} \item UNCERTAINTY DURING EXECUTION OF OPERATIONS IS ALWAYS PRESENT \item THIS IS PARTICULARLY TROUBLESOME IF THE NETWORK ``BREAKS'' AFTER A REQUEST IS RECEIVED BY THE PERFORMER BUT BEFORE THE INVOKER RECEIVES THE REPLY \item ONE SCHEME OF CLASSIFYING THE RELIABILITY REQUIREMENTS OF AN OPERATION IS: \begin{nrtc} \item EXACTLY ONCE \item AT LEAST ONCE (IDEMPOTENT) \item AT MOST ONCE \end{nrtc} \item IMPLEMENTING THESE SEMANTICS IS THE RESPONSBILITY OF THE ROS-USER \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {RELIABILITY CHARACTERISTIC:\\ EXACTLY ONCE} \begin{nrtc} \item PERFORMER \begin{nrtc} \item KEEPS TRACK OF THE INVOCATION IDENTIFIERS OF ALL PERFORMED OPERATIONS \item WHEN PROCESSING AN INVOCATION, IF AN INVOCATION IDENTIFIER IS REPEATED, REJECT THE OPERATION \end{nrtc} \item INVOKER \begin{nrtc} \item REPEATEDLY INVOKES THE OPERATION USING THE SAME INVOCATION IDENTIFIER UNTIL EITHER \item A CONFIRMATION (RESULT OR ERROR) IS RECEIVED, OR \item A REJECTION (DUPLICATE OPERATION) IS RECEIVED \end{nrtc} \item A ROS BUG: REJECTION DOES NOT INCLUDE THE VALUE OF THE PREVIOUS RESULT! \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {RELIABILITY CHARACTERISTIC:\\ AT LEAST ONCE} \begin{nrtc} \item PERFORMER \begin{nrtc} \item KEEPS NO INFORMATION REGARDING PREVIOUSLY PERFORMED OPERATIONS \end{nrtc} \item INVOKER \begin{nrtc} \item REPEATEDLY INVOKES THE OPERATION \begin{nrtc} \item (WITH ANY INVOCATION IDENTIFIER) \end{nrtc} UNTIL A CONFIRMATION (RESULT OR ERROR) IS RECEIVED \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {RELIABILITY CHARACTERISTIC:\\ AT MOST ONCE} \begin{nrtc} \item PERFORMER \begin{nrtc} \item KEEPS NO INFORMATION REGARDING PREVIOUSLY PERFORMED OPERATIONS \end{nrtc} \item INVOKER \begin{nrtc} \item INVOKES THE OPERATION \begin{nrtc} \item (WITH ANY INVOCATION IDENTIFIER) \end{nrtc} EXACTLY ONCE \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {AN EXAMPLE (cont.)} \vskip.15in \begin{verbatim} int op_EVAL_evalOperation (sd, in, out, rsp, roi) int sd; struct type_EVAL_EvalObject* in; caddr_t *out; int *rsp; struct RoSAPindication *roi; \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {AN EXAMPLE (cont.)} \vskip.15in \begin{verbatim} struct type_EVAL_Service__Requirements { struct type_EVAL_Versions *version; struct type_EVAL_Credentials *credentials; struct member_EVAL_0 { struct type_EVAL_Extension *Extension; struct member_EVAL_0 *next; } *extensions; }; \end{verbatim} \end{bwslide} \begin{bwslide} \part {THE RO-NOTATION}\bf \begin{nrtc} \item USE ASN.1 MACROS TO DEFINE APPLICATION PROTOCOL \begin{nrtc} \item APPLICATION CONTEXTS \item PARAMETERS NEEDED FOR BINDING AND INVOCATION \end{nrtc} \item A STANDARD SET OF MACROS, THE \emph{RO-NOTATION}, IS DEFINED FOR THIS PURPOSE \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {AN ANNOTATED EXAMPLE} \hrule\vskip.15in \begin{tgrind}\scriptsize \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-15\relax \end{tgrind} \end{bwslide} \begin{bwslide} \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-16\relax \end{tgrind} \end{bwslide} \begin{bwslide} \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-17\relax \end{tgrind} \end{bwslide} \begin{bwslide} \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-18\relax \end{tgrind} \end{bwslide} \begin{bwslide} \begin{tgrind}\scriptsize \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-19\relax \end{tgrind} \end{bwslide} \begin{bwslide} \begin{tgrind}\scriptsize \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-20\relax \end{tgrind} \end{bwslide} \begin{bwslide} \begin{tgrind}\scriptsize \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-21\relax \end{tgrind} \end{bwslide} \begin{bwslide} \begin{tgrind}\scriptsize \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-22\relax \end{tgrind} \end{bwslide} \begin{bwslide} \part {STATIC FACILITIES}\bf \begin{nrtc} \item STUB GENERATOR \item STRUCTURE GENERATOR \item ELEMENT PARSER \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {STATIC FACILITIES\\ OVERVIEW} \vskip.15in \diagram[p]{figureB-1} \end{bwslide} \begin{bwslide} \part* {STUB GENERATOR}\bf \begin{nrtc} \item WHAT WE WOULD LIKE: MAGIC! \item WHAT WE REALLY GET: HARD WORK. \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {CONCEPT: STUBS} \begin{nrtc} \item A PROCEDURE WHICH IS CALLED LOCALLY BUT EXECUTES REMOTELY \item IN OUR CONTEXT, A SYNCHRONOUS STUB: \begin{nrtc} \item INVOKES THE OPERATION \item AWAITS A RESPONSE \item RETURNS A RESULT OR ERROR \end{nrtc} \item AN ASYNCHRONOUS STUB: \begin{nrtc} \item INVOKES THE OPERATION, AND EVENTUALLY \item DISPATCHES A RESULT OR ERROR HANDLER \end{nrtc} \item WHAT TO DO ABOUT REJECTIONS, NETWORK PROBLEMS, etc.? \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {ROSY} \begin{nrtc} \item REMOTE OPERATIONS STUB-GENERATOR (YACC-BASED) \item INPUT: \begin{nrtc} \item A RO SPEC \end{nrtc} \item OUTPUT: \begin{nrtc} \item AN ASN.1 SPEC \item STUB DEFINITIONS FOR C \item C DATA STRUCTURES FOR RUN-TIME ENVIRONMENT \item STUB DEFINITIONS FOR LINT \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ EVAL SERVICE}\small \vskip.15in \begin{verbatim} % rosy eval.ry EVAL operations: evalOperation read write EVAL errors: evalError endOfInput EVAL types: EvalObject Service-Requirements Versions Service-Diagnostic Diagnostic-Reason ServiceProblem SecurityProblem \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ STUB DEFINITIONS FOR C}\small \vskip.15in \begin{verbatim} #define operation_EVAL_evalOperation 0 #define stub_EVAL_evalOperation(sd,id,in,rfx,efx,class,roi)\ RyStub ((sd), table_EVAL_Operations,\ operation_EVAL_evalOperation, (id), NULLIP,\ (caddr_t) (in), (rfx), (efx), (class), (roi)) #define op_EVAL_evalOperation(sd,in,out,rsp,roi)\ RyOperation ((sd), table_EVAL_Operations,\ operation_EVAL_evalOperation,\ (caddr_t) (in), (out), (rsp), (roi)) #define error_EVAL_evalError 0 \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ C DATA STRUCTURES FOR\\ RUN-TIME ENVIRONMENT}\small \vskip.15in \begin{verbatim} struct RyOperation table_EVAL_Operations[] = { /* OPERATION evalOperation */ "evalOperation", operation_EVAL_evalOperation, encode_EVAL_evalOperation_argument, decode_EVAL_evalOperation_argument, free_EVAL_evalOperation_argument, 1, encode_EVAL_evalOperation_result, decode_EVAL_evalOperation_result, free_EVAL_evalOperation_result, errors_EVAL_evalOperation, ... NULL }; \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ C DATA STRUCTURES FOR\\ RUN-TIME ENVIRONMENT\\ (cont.)} \small \vskip.15in \begin{verbatim} static struct RyError *errors_EVAL_evalOperation[] = { &table_EVAL_Errors[0] }; \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ C DATA STRUCTURES FOR\\ RUN-TIME ENVIRONMENT\\ (cont.)} \small \vskip.15in \begin{verbatim} struct RyError table_EVAL_Errors[] = { /* ERROR evalError */ "evalError", error_EVAL_evalError, encode_EVAL_evalError_parameter, decode_EVAL_evalError_parameter, free_EVAL_evalError_parameter, ... NULL }; \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ STUB DEFINITIONS FOR LINT}\small \vskip.15in \begin{verbatim} int stub_EVAL_evalOperation (sd, id, in, rfx, efx, class, roi) int sd, id, class; struct type_EVAL_EvalObject* in; IFP rfx, efx; struct RoSAPindication *roi; { return RyStub (sd, table_EVAL_Operations, operation_EVAL_evalOperation, id, NULLIP, (caddr_t) in, rfx, efx, class, roi); } \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ STUB DEFINITIONS FOR LINT (cont.)}\small \vskip.15in \begin{verbatim} int op_EVAL_evalOperation (sd, in, out, rsp, roi) int sd; struct type_EVAL_EvalObject* in; caddr_t *out; int *rsp; struct RoSAPindication *roi; { return RyOperation (sd, table_EVAL_Operations, operation_EVAL_evalOperation, (caddr_t) in, out, rsp, roi); } \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {ROSY LIMITATIONS} \begin{nrtc} \item SOMEWHAT LIMITED IN THE FRONT-END, CURRENTLY RECOGNIZES ONLY \begin{nrtc} \item \verb"OPERATION" AND \verb"ERROR" MACROS \end{nrtc} \item BUT DOESN'T KNOW ABOUT \verb"OBJECT IDENTIFIER" NOTATION FOR OPERATION CODES \item AND IGNORES THE \verb"LINKED" CLAUSE IN OPERATIONS \end{nrtc} \end{bwslide} \begin{bwslide} \part* {STRUCTURE GENERATOR}\bf \begin{nrtc} \item WHAT WE WOULD LIKE: MAGIC! \item WHAT WE REALLY GET: HARD WORK. \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {SERIALIZING DATA STRUCTURES} \begin{nrtc} \item THE BASIC ENCODING RULES SAY HOW TO MAP THE ABSTRACT SYNTAX TO THE TRANSFER SYNTAX \item HOW TO MAP DATA STRUCTURES (CONCRETE STRUCTURE) TO THE ABSTRACT SYNTAX? \begin{nrtc} \item \verb"struct { ... }" $\rightarrow$ \verb"ServiceRequirements" \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {A SOLUTION} \begin{nrtc} \item GENERATE C STRUCTURES DIRECTLY FROM ABSTRACT SYNTAX \item GENERATE TRANSLATOR TO DO THE MAPPING \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {SIMPLE TYPES} \begin{nrtc} \item \verb"BOOLEAN" $\rightarrow$ \verb"char" \item \verb"INTEGER" $\rightarrow$ \verb"int", e.g., \begin{nrtc} \item \verb"typedef long integer;" \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {SIMPLE TYPES (cont.)} \begin{nrtc} \item FOR RANGE-LIMITED INTEGERs, SYMBOLIC VALUES ARE DEFINED AS WELL \small\begin{verbatim} SecurityProblem ::= INTEGER { inappropriateAuthentication(1), invalidCredentials(2), ... } struct type_EVAL_SecurityProblem { integer parm; #define int_EVAL_SecurityProblem_inappropriateAuthentication 1 #define int_EVAL_SecurityProblem_invalidCredentials 2 ... }; \end{verbatim} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {SIMPLE TYPES (cont.)} \begin{nrtc} \item \verb"BIT STRING" $\rightarrow$ \verb"struct PElement" \begin{verbatim} Versions ::= BIT STRING { version-1(0), ... } #define type_EVAL_Versions PElement #define bits_EVAL_Versions "\020\01version-1 ..." #define bit_EVAL_Versions_version__1 0 #define free_EVAL_Versions pe_free \end{verbatim} \item \verb"OCTET STRING" $\rightarrow$ \verb"struct qbuf" \item \verb"OBJECT IDENTIFIER" $\rightarrow$ \verb"struct OIDentifier" \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {COMPLEX TYPES:\\ SEQUENCE OF} \begin{nrtc} \item A LINKED LIST WITH SOME GENERATED NAMES \begin{verbatim} SEQUENCE OF Versions struct element_EVAL_0 { struct type_EVAL_Versions *Versions; struct element_EVAL_0 *next; } *versions; \end{verbatim} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {COMPLEX TYPES:\\ SEQUENCE/SET} \begin{nrtc} \item A ``SIMPLE'' STRUCTURE USING TAGS FOR NAMES,\\ WHENEVER POSSIBLE \begin{verbatim} Service-Requirements ::= SEQUENCE { version[0] Versions, credentials[1] Credentials OPTIONAL, ... } struct type_EVAL_Service__Requirements { struct type_EVAL_Versions *version; struct type_EVAL_Credentials *credentials; ... }; \end{verbatim} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {COMPLEX TYPES:\\ CHOICE} \begin{nrtc} \item A STRUCTURE WITH A TAG AND A UNION \small\begin{verbatim} Diagnostic-Reason ::= CHOICE { serviceError[1] ServiceProblem, securityError[2] SecurityProblem } struct type_EVAL_Diagnostic__Reason { int offset; #define type_EVAL_Diagnostic__Reason_serviceError 1 #define type_EVAL_Diagnostic__Reason_securityError 2 union { struct type_EVAL_ServiceProblem *serviceError; struct type_EVAL_SecurityProblem *securityError; } un; }; \end{verbatim} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {DEFAULT/OPTIONAL} \begin{nrtc} \item A VERY SLICK FACILITY WOULD BE TO SUPPORT THE \verb"DEFAULT" AND \verb"OPTIONAL" CLAUSES FOR COMPLEX TYPES \item BUT, IMPLEMENTATION IS PROBLEMATIC: \begin{nrtc} \item NEED ASN.1 VALUE PARSING IN FRONT-END \item NEED EXTENSIVE SYMBOL TABLE SEMANTICS IN BACK-END \end{nrtc} \item SO, A SIMPLE APPROACH IS TAKEN \begin{nrtc} \item SCALARS ARE HANDLED DIRECTLY: \begin{nrtc} \item BOOLEANS, INTEGERS \end{nrtc} \item NON-SCALARS ARE EXAMINED FOR INEQUALITY TO \verb"NULL" \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {HEURISTICS} \begin{nrtc} \item IF ONLY ONE MEMBER IN CONSTRUCTOR, PULL IT UP \begin{verbatim} ErrorInfo ::= SEQUENCE { errorStatus[0] IMPLICIT ErrorStatus } \end{verbatim} \verb"ErrorInfo" $\rightarrow$ \verb"struct type_EVAL_ErrorStatus" \item TRY TO USE TAGS FOR STRUCTURE NAMES, WHENEVER POSSIBLE \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {POSY} \begin{nrtc} \item PEPY OPTIONAL STRUCTURE-GENERATOR (YACC-BASED) \item INPUT: \begin{nrtc} \item AN ASN.1 SPEC \end{nrtc} \item OUTPUT: \begin{nrtc} \item AN AUGMENTED ASN.1 SPEC \item C STRUCTURE DEFINITIONS \item ``FREE'' ROUTINES \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ EVAL SERVICE}\small \vskip.15in \begin{verbatim} % posy -f -h -o eval-asn.py eval.py EVAL types: EvalObject Service-Requirements Versions Service-Diagnostic Diagnostic-Reason ServiceProblem SecurityProblem \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ C STRUCTURE DEFINITIONS}\scriptsize \vskip.15in \begin{verbatim} Service-Requirements ::= SEQUENCE { version[0] Versions, credentials[1] Credentials OPTIONAL, extensions[2] SET OF Extension OPTIONAL } struct type_EVAL_Service__Requirements { struct type_EVAL_Versions *version; struct type_EVAL_Credentials *credentials; struct member_EVAL_0 { struct type_EVAL_Extension *Extension; struct member_EVAL_0 *next; } *extensions; }; \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ ``FREE'' ROUTINES}\small \vskip.15in \begin{verbatim} free_EVAL_Service__Diagnostic (arg) struct type_EVAL_Service__Diagnostic *arg; { struct element_EVAL_0 *versions, versions_next; if (arg == NULL) return; for (versions = arg -> versions; versions; versions = versions_next) { versions_next = versions -> next; free_EVAL_Versions (versions -> Versions); free ((char *) versions); } arg -> versions = NULL; ... free ((char *) arg); } #define free_EVAL_Versions pe_free \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {POSY LIMITATIONS} \begin{nrtc} \item STEMS FROM A LACK OF INTELLIGENCE WHEN DEALING WITH COMPLEX ASN.1 VALUE NOTATION: \begin{nrtc} \item USES ``NULL INEQUALITY'' RULE FOR \verb"OPTIONAL" \item HANDLES \verb"DEFAULT" ONLY FOR SCALARS \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \part* {ELEMENT PARSER}\bf \begin{nrtc} \item WE NOW KNOW ABOUT \begin{nrtc} \item DATA STRUCTURES\ \ \verb"struct { ... }" \item ABSTRACT SYNTAX\ \ \verb"ServiceRequirements" \item TRANSFER SYNTAX\ \ \verb"1f8a ..." \end{nrtc} \item THE \emph{PRESENTATION ELEMENT} TIES THESE TOGETHER \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PRESENTATION ELEMENTS} \begin{nrtc} \item AN INTERNAL FORM FOR AN INSTANCE OF A TYPE DESCRIBED BY ABSTRACT SYNTAX \item CAN REPRESENT ANY ASN.1 TYPE AS EITHER \begin{nrtc} \item A STRING OF OCTETS OR BITS \item A LINKED-LIST OF PRESENTATION ELEMENTS \end{nrtc} \item THE CONCEPTUAL MAPPING IS: \begin{nrtc} \item \verb"struct { ... }" $\rightarrow$ \verb"ServiceRequirements" \end{nrtc} \item THE ACTUAL MAPPING IS: \begin{nrtc} \item \verb"struct { ... }" $\rightarrow$ \verb"struct PElement" \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PEPY} \begin{nrtc} \item PRESENTATION ELEMENT PARSER (YACC-BASED) \item INPUT: \begin{nrtc} \item AN AUGMENTED ASN.1 SPEC \end{nrtc} \item OUTPUT: \begin{nrtc} \item AN ENCODER \item A DECODER \item A PRETTY-PRINTER \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE:\\ EVAL SERVICE}\small \vskip.15in \begin{verbatim} % pepy eval-asn.py EVAL encode none none: EvalObject Service-Requirements Versions Service-Diagnostic Diagnostic-Reason ServiceProblem SecurityProblem EVAL none decode none: EvalObject Service-Requirements Versions Service-Diagnostic Diagnostic-Reason ServiceProblem SecurityProblem \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {STATIC FACILITIES:\\ REVIEW} \vskip.15in \diagram[p]{figureB-1} \end{bwslide} \begin{bwslide} \ctitle {NEW DEVELOPMENT:\\ PEPSY} \begin{nrtc} \item PEPY WRITES LL(1) C ROUTINES \begin{nrtc} \item STRAIGHT-FORWARD TO IMPLEMENT\\ BUT LARGE CODE SIZE \end{nrtc} \item NEW WORK HAS RESULTED IN A COMPILER THAT PRODUCES \begin{nrtc} \item C STRUCTURE DEFINITIONS (LIKE POSY) \item COMPILED TABLES \item AN LL(1) INTERPRETER \end{nrtc} CALLED PEPSY \item RESULT IS SMALLER CODE AND FASTER COMPILES \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {EXAMPLE: PEPSY} \vskip.15in \begin{quote}\small\begin{verbatim} % rosy -pepsy eval.ry EVAL operations: evalOperation read write EVAL errors: evalError endOfInput EVAL types: EvalObject Service-Requirements Versions Service-Diagnostic Diagnostic-Reason ServiceProblem SecurityProblem % pepsy -A -f -h eval.py EVAL types: EvalObject Service-Requirements Versions Service-Diagnostic Diagnostic-Reason ServiceProblem SecurityProblem % cc -c EVAL_tables.c ... \end{verbatim}\end{quote} \end{bwslide} \begin{bwslide} \ctitle {STATIC FACILITIES:\\ PEPSY} \vskip.15in \diagram[p]{figureB-23} \end{bwslide} \begin{bwslide} \part {DYNAMIC FACILITIES}\bf \begin{nrtc} \item RUN-TIME ENVIRONMENT \item BOILERPLATE FOR INVOKERS \item BOILERPLATE FOR PERFORMERS \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {DYNAMIC FACILITIES\\ OVERVIEW} \vskip.15in \diagram[p]{figureB-2} \end{bwslide} \begin{bwslide} \part* {RUN-TIME ENVIRONMENT}\bf \begin{nrtc} \item RUN-TIME ENVIRONMENT RESPONSIBLE FOR ``CIVILIZING'' REMOTE OPERATIONS SERVICE \item IMPORTANT TRADE-OFF: \begin{nrtc} \item FLEXIBILITY FOR SIMPLICITY \end{nrtc} \item IN \emph{THE COOKBOOK}, \verb"ROSYLIB" IMPLEMENTS THE RUN-TIME ENVIRONMENT \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {DATA STRUCTURES} \begin{nrtc} \item RECALL THAT ROSY GENERATES TABLES IN ADDITION TO STUBS \item FOR EACH OPERATION, A TABLE IS DEFINED CONTAINING: \begin{nrtc} \item NAME AND NUMBER OF OPERATION \item ARGUMENT ENCODE/DECODE/FREE ROUTINES \item RESULT ENCODE/DECODE/FREE ROUTINES \item ERROR TABLE \end{nrtc} \end{nrtc}\small \begin{verbatim} ... /* OPERATION evalOperation */ "evalOperation", operation_EVAL_evalOperation, encode_EVAL_evalOperation_argument, decode_EVAL_evalOperation_argument, free_EVAL_evalOperation_argument, 1, encode_EVAL_evalOperation_result, decode_EVAL_evalOperation_result, free_EVAL_evalOperation_result, errors_EVAL_evalOperation, ... \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {DATA STRUCTURES (cont.)} \begin{nrtc} \item FOR EACH ERROR, A TABLE IS DEFINED CONTAINING: \begin{nrtc} \item NAME AND NUMBER OF ERROR \item PARAMETER ENCODE/DECODE/FREE ROUTINES \end{nrtc} \end{nrtc}\small \begin{verbatim} ... /* ERROR evalError */ "evalError", error_EVAL_evalError, encode_EVAL_evalError_parameter, decode_EVAL_evalError_parameter, free_EVAL_evalError_parameter, ... \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {A TABLE-DRIVEN APPROACH} \begin{nrtc} \item RUN-TIME ENVIRONMENT SHOULD BE GENERALIZED TO WORK WITH THE LARGEST POSSIBLE SET OF APPLICATIONS USING REMOTE OPERATIONS \item A TABLE-DRIVEN APPROACH PERMITS US TO DECOUPLE OPERATION-SPECIFIC INFORMATION \begin{nrtc} \item WHAT ARGUMENTS REPRESENTED, HOW THEY ARE ENCODED, etc. \end{nrtc} FROM OPERATION-GENERIC INFORMATION \begin{nrtc} \item THE OPERATION TAKES ARGUMENTS WHICH MUST BE ENCODED, etc. \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {STUBS REVISITED} \begin{nrtc} \item STUBS DEFINED BY ROSY CALL EITHER THE \verb"RyOperation" OR THE \verb"RyStub" ROUTINE \item THE \verb"RyOperation" ROUTINE IMPLEMENTS A ``POLICY'' \begin{nrtc} \item OPERATION CLASS: SYNCHRONOUS \item INVOCATION IDENTIFIER: UNIQUE NUMBER \item LINKED-INVOCATION ID: NONE \item PRIORITY: NONE \end{nrtc} \item THE \verb"RyStub" ROUTINE IMPLEMENTS A LESS RESTRICTIVE POLICY: \begin{nrtc} \item USER SELECTS OPERATION CLASS AND INVOCATION IDENTIFIER \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {ASYNCHRONOUS STUBS} \begin{nrtc} \item RECALL {\small \begin{verbatim} #define stub_EVAL_evalOperation(sd,id,in,rfx,efx,class,roi)\ RyStub ((sd), table_EVAL_Operations,\ operation_EVAL_evalOperation, (id), NULLIP,\ (caddr_t) (in), (rfx), (efx), (class), (roi)) \end{verbatim}} \item THE MEANING OF THE PARAMETERS: \begin{nrtc} \item \verb"sd": ASSOCIATION-DESCRIPTOR \item \verb"id": INVOCATION IDENTIFIER \item \verb"in": ARGUMENT FOR OPERATION \item \verb"rfx": DISPATCH ROUTINE FOR RESULT \item \verb"efx": DISPATCH ROUTINE FOR ERRORS OR REJECTIONS \item \verb"class": (A)SYNCHRONOUS \item \verb"roi": LOCAL SERVICE INTERFACE INFORMATION \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {INSIDE RYSTUB} \begin{nrtc} \item RUDIMENTARY PARAMETER CHECK \item BUILD PRESENTATION ELEMENT FOR ARGUMENT \item BUILD \emph{ACTIVATION BLOCK} \item ISSUE RO-INVOKE.REQUEST \item IF ASYNCHRONOUS, RETURN \item LOOP, WAITING FOR ANY RESPONSE: \begin{nrtc} \item RO-INVOKE.INDICATION: \begin{nrtc} \item PUSH ACTIVATION BLOCK FOR DISPATCHING OPERATION \end{nrtc} \item RO-RESULT, ERROR, OR REJECTION.INDICATION: \begin{nrtc} \item PARSE OPERATION RESULT OR ERROR PARAMETER AND CALL DISPATCH ROUTINE \begin{verbatim} result = (*fnx) (sd, id, reason, value, roi); \end{verbatim} \item IF RESPONSE WAS FOR US, RETURN \end{nrtc} \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {SYNCHRONOUS STUBS} \begin{nrtc} \item RECALL \begin{verbatim} #define op_EVAL_evalOperation(sd,in,out,rsp,roi)\ RyOperation ((sd), table_EVAL_Operations,\ operation_EVAL_evalOperation,\ (caddr_t) (in), (out), (rsp), (roi)) \end{verbatim} \item THE MEANING OF THE PARAMETERS: \begin{nrtc} \item \verb"sd": ASSOCIATION-DESCRIPTOR \item \verb"in": ARGUMENT FOR OPERATION \item \verb"out": RESULT FOR OPERATION OR PARAMETER FOR ERROR \item \verb"rsp": TELLS HOW TO INTERPRET \verb"out" \item \verb"roi": REJECTION INFORMATION FOR OPERATION \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {INSIDE RYOPERATION} \begin{nrtc} \item RUDIMENTARY PARAMETER CHECK \item BUILD PRESENTATION ELEMENT FOR ARGUMENT \item BUILD \emph{ACTIVATION BLOCK} \item ISSUE RO-INVOKE.REQUEST \item LOOP, WAITING FOR SOME RESPONSE: \begin{nrtc} \item RO-INVOKE.INDICATION: \begin{nrtc} \item PUSH ACTIVATION BLOCK FOR DISPATCHING OPERATION \end{nrtc} \item RO-RESULT, ERROR, OR REJECTION.INDICATION: \begin{nrtc} \item IF FOR US: PARSE OPERATION RESULT OR ERROR PARAMETER AND RETURN \item IF NOT FOR US: STUFF INFORMATION INTO CORRESPONDING ACTIVATION BLOCK \end{nrtc} \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PERFORMERS} \begin{nrtc} \item REGISTER A DISPATCH ROUTINE FOR EACH OPERATION USING \verb"RyDispatch" \begin{verbatim} RyDispatch (sd, ryo, op, fnx, roi) \end{verbatim} \item THE MEANING OF THE PARAMETERS: \begin{nrtc} \item \verb"sd": ASSOCIATION-DESCRIPTOR \item \verb"ryo": OPERATION TABLE \item \verb"op": OPERATION NUMBER \item \verb"fnx": DISPATCH ROUTINE \item \verb"roi": FAILURE INDICATOR \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {OPERATION DISPATCH} \begin{nrtc} \item WHILE WAITING FOR ``SOMETHING TO HAPPEN'', A RO-INVOKE.INDICATION CAUSES AN ACTIVATION BLOCK TO BE PUSHED \item THE PRESENTATION ELEMENT FOR THE ARGUMENT IS PARSED INTO A STRUCTURE AND THE DISPATCH ROUTINE IS CALLED: \begin{verbatim} result = (*fnx) (sd, ryo, rox, arg, roi) \end{verbatim} \item DISPATCH ROUTINE HAS THREE OPTIONS \begin{nrtc} \item \verb"RyDsResult": TO RETURN A RESULT \item \verb"RyDsError": TO RETURN AN ERROR \item \verb"RyDsUReject": TO REJECT AN OPERATION \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {CLEAN-UP} \begin{nrtc} \item WHEN AN ASSOCIATION IS ABORTED (e.g., DUE TO NETWORK FAILURE), SOMETHING MUST BE DONE WITH ACTIVATION BLOCKS \item IDEALLY, WOULD LIKE TO: \begin{nrtc} \item RETAIN THIS STATE, \item RE-ESTABLISH THE ASSOCIATION, AND \item CONTINUE WHERE WE LEFT OFF \end{nrtc} \item NO SUCH LUCK, ACTIVATION BLOCKS ARE FLUSHED! \begin{nrtc} \item A LOT OF HARD ISSUES NEED TO BE RESOLVED IN ORDER TO DO THE ``RIGHT THING'' \item ACTUALLY, FOR ASYNCHRONOUS INVOCATIONS, A REJECTION IS PASSED UP \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \part* {BOILERPLATE FOR INVOKERS}\bf \begin{nrtc} \item THE PROBLEM WITH BOILERPLATE IS THAT IT'S BORING \item SO, WE'LL CONSIDER ONLY THE HIGHLIGHTS \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {INVOKING AN OPERATION} \begin{nrtc} \item ALTHOUGH \emph{THE COOKBOOK} TRIED TO MAKE THINGS SIMPLE, CALLING A STUB IS NOT EASY \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {ASYNCHRONOUS INVOCATION}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-3\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {ASYNCHRONOUS INVOCATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-4\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {ASYNCHRONOUS INVOCATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-5\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {ASYNCHRONOUS INVOCATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-6\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {ASYNCHRONOUS INVOCATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-7\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {SIMPLIFIED ASYNCHRONOUS INVOCATION}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-8\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {SYNCHRONOUS INVOCATION}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-9\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {SYNCHRONOUS INVOCATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-10\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {SYNCHRONOUS INVOCATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-11\relax \end{tgrind} \end{bwslide} \begin{bwslide} \part* {BOILERPLATE FOR PERFORMERS}\bf \begin{nrtc} \item THE PROBLEM WITH BOILERPLATE IS THAT IT'S BORING \item SO, WE'LL CONSIDER ONLY THE HIGHLIGHTS \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PERFORMING AN OPERATION} \begin{nrtc} \item WHEN AN ACTIVATION BLOCK IS PUSHED, THE DISPATCH ROUTINE IS CALLED \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {PERFORMING AN OPERATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-12\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {PERFORMING AN OPERATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-13\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {PERFORMING AN OPERATION (cont.)}\small \hrule\vskip.15in \begin{tgrind} \let\linebox=\relax \def\_{\ifstring{\char'137}\else\underline{\ }\fi} \input figureB-14\relax \end{tgrind} \end{bwslide} \begin{bwslide} \ctitle {DYNAMIC FACILITIES:\\ REVIEW} \vskip.15in \diagram[p]{figureB-2} \end{bwslide} \ifpractical \let\foo=\relax \else \begin{bwslide} \ctitle {FOR FURTHER READING} \begin{nrtc} \item Volume 4: The Applications Cookbook \item The Applications Cookbook\\ Julian P.~Onions and Marshall T.~Rose\\ Proceedings, Fourth International Symposium on Computer Message Systems, September, 1988 \end{nrtc} \end{bwslide} \let\foo=\endinput \fi \foo \begin{bwslide} \part {EXTRA FOR EXPERTS!}\bf \begin{nrtc} \item THESE TOOLS CAN BE GENERALIZED FOR OTHER APPLICATION ENVIRONMENTS \item NEVER CONFUSE PROGRAMMATIC INTERFACES WITH USER INTERFACES \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {NETWORK MANAGEMENT} \begin{nrtc} \item SUPPOSE YOU HAVE A SIMPLE NETWORK MANAGEMENT PROTOCOL WITH OPERATIONS TO \begin{nrtc} \item GET A VARIABLE \item GET A ROW IN A TABLE \end{nrtc} \item AND YOU WANT TO PROTOTYPE MANGEMENT APPLICATIONS \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {TWO THINGS ARE NEEDED} \begin{nrtc} \item AN APPLICATIONS FRAMEWORK FOR THE USER \item AUTOMATIC GENERATION OF NETWORK MANAGEMENT PDUs \begin{nrtc} \item AND THE GLUE BETWEEN THEM \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {APPLICATIONS FRAMEWORK:\\ AWK} \begin{nrtc} \item A PATTERN SCANNING AND PROCESSING LANGUAGE \item USEFUL FOR PROTOTYPING TEXT-HANDLING APPLICATIONS \item INTERPRETIVE LANGUAGE \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {AUTOMATIC GENERATION OF\\ NETWORK MANAGEMENT PDUs:\\ THE COOKBOOK} \begin{nrtc} \item USE PEPSY TO DEFINE AND IMPLEMENT API FOR LOW-LEVEL PROTOCOL INTERACTIONS \begin{nrtc} \item IF MANAGEMENT PROTOCOL WAS CMIP, THEN COULD USE ROSY TOO \end{nrtc} \item NOW JUST MODIFY AWK A BIT$\ldots$ \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {MODIFICATIONS TO AWK:\\ VARIABLES} \begin{nrtc} \item IN FRONT-END, WHEN VARIABLES ARE USED, SEE IF THEY ARE DEFINED IN THE MANAGEMENT INFORMATION BASE \item FOR SIMPLE VARIABLES: \begin{verbatim} sysDescr sysDescr[value] \end{verbatim} \item FOR TABULAR VARIABLES: \begin{verbatim} ifDescr[value] for (i in ifDescr) print "%d: %s", ifIndex, ifDescr; \end{verbatim} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {MODIFICATIONS TO AWK:\\ VARIABLES (cont.)} \begin{nrtc} \item WHEN VARIABLE APPEARS IN AN ``RVALUE'', USE MANAGEMENT PROTOCOL TO RETRIEVE VALUE \item ADD A FEW NEW VARIABLES TO HELP OUT \begin{nrtc} \item e.g., AGENT ADDRESS \end{nrtc} \item ONLY TRICKY PART: WHEN TRAVERSING TABLE, RETRIEVE EACH ROW IN ONE OPERATION \begin{nrtc} \item REDUCES NETWORK TRAFFIC \item REDUCES CHANCE OF INCONSISTENT VIEWS \end{nrtc} \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {MODIFICATIONS TO AWK:\\ DATA TYPING} \begin{nrtc} \item INTEGER: number \item OCTET STRING: string (\verb|"%02x: ... :%02x"|) \item OBJECT IDENTIFIER: string (\verb|"%u. ... .%u"|) \item and so on$\ldots$ \end{nrtc} \end{bwslide} \begin{bwslide} \ctitle {AN EXAMPLE} \vspace{0.5in} \smaller \begin{verbatim} printf "Routing tables\n"; printf "%-15s %-15s %-8s %-6s %-10s %s\n", "Destination", "Gateway", hasunix ? "Flags" : "Type", "Refcnt", "Use", "Interface"; \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {AN EXAMPLE (cont.)} \vspace{0.5in} \smaller \begin{verbatim} didone = 0; for (i in ipRouteDest) { didone = 1; printf "%-15s %-15s %-8s %-6s %-10s %s (#%d)\n", ipRouteDest == "0.0.0.0" ? "default" : ipRouteDest, ipRouteNextHop, hasunix ? rt_flags(unixIpRouteFlags[i]) \ : rt_type(ipRouteType), hasunix ? unixIpRouteRefCnt[i] : "", hasunix ? unixIpRouteUses[i] : "", ifDescr[ipRouteIfIndex], ipRouteIfIndex; } if (!didone && DIAGNOSTIC) printf "ipRoutingTable: %s\n", DIAGNOSTIC; \end{verbatim} \end{bwslide} \begin{bwslide} \ctitle {AN EXAMPLE (cont.)} \vspace{0.5in} \smaller \begin{verbatim} % gawk -f mib.routes Routing tables Destination Gateway Flags Refcnt Use Interface default 192.52.180.3 UG 5 63813 le0 (#1) 127.0.0.0 127.0.0.1 U 22 31804 lo0 (#2) 192.52.180.0 192.52.180.1 U 7 167235 le0 (#1) \end{verbatim} \end{bwslide}