arXiv:1705.08708v1 [cs.NI] 24 May 2017 oig .. [ C.2.6 toring; Networks Communication Networks aeoisadSbetDescriptors Subject and Categories into ASN.1 from definitions generation MIB Lisp. “code Common SNMP the compiling especially detai on package, implementation approach SNMP the and and design ASN.1 native the Lisp the then and uc uoilof tutorial quick a whic projects. implemented, related other also an for useful are and be package package would runtime networking and UDP compiler portable ASN.1 general an opment, 5 09 abig,Msahsts S,p.1–10. pp. USA, Massachusetts, Li Cambridge, International 2009, the 25, of Proceedings ILC’09, from Reprinted 1 tnad;D34[ D.3.4 Standards; hpbtenLs n NPhvntbe tde nuhdurin enough studied years. been 20 haven’t rel past SNMP the and However, Lisp rem not. between other or ship monitor Lisp-based to either mo are need be which may systems need who Lispers may there’re which and tored, applications commun Lisp-based Lisp large In today. there’re network fo used Internet-based widely of is management (SNMP) Protocol Management Network Simple Abstract Keywords Terms General generation ewr aaeetadSM tef u h otimportant, most SNMP implement the to prove: But to tries itself. project SNMP this researc and for platform management flexible SNMP-based network a side, any also through server It’s remote applicatio system. on from management based and monitored Lisp peers, be Common could SNMP into which remote capability query side SNMP to brings client it used On be protocol. can SNMP it the implemented which package include CL http://common-lisp.net/project/cl-net-snmp - nti ae,teato rtitoue h NPpooo a protocol SNMP the introduces first author the paper, this In The ifrn rmohreitSM rjcso omnLisp, Common on projects SNMP exist other from Different NET CL - SNMPv3 SNMP :NtokPooosApiain;C23[ C.2.3 Protocols—Applications; Network ]: - NET ip NP ASN.1 SNMP, Lisp, optrCmuiainNetworks Computer-Communication scerytree nfl NPpooo support protocol SNMP full on targeted clearly is - SNMP agae,NtokManagement Network Languages, n evrsd ok(gn) uigtedevel- the During (agent). work server-side and CL rgamn Languages Programming . - 1 NET rjc a eeoe e omnLisp Common new a developed has project :NtokOeain—ewr moni- Operations—Network Network ]: omnLs stems tlanguage fit most the is Lisp Common - SNMP nbt letadsre sides, server and client both on .. 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SourceForge.net SEQUENCE SNMPv1 hr’eams 0 projects 300 almost there’re , n l NPpro- SNMP all and , SNMPv1 [6], SNMPv2c and rganized efacto de called y nslated ,from t, packet n a ing rma- by n One SN- N.1 op- ing [7] ee P) n- e- m ly ht P, d - . ular languages like Java, Python or C#, there’re often several sim- 2. CL-NET-SNMP Tutorial ilar projects existing in competition. And there’s at least one lan- 2.1 Client-side SNMP guage, Erlang, which ships full SNMP support (more than 60,000 lines of code) with the language itself 2. J. Schonwalder wrote a The client-side API of SNMP package is quite straight-forward. good summary [J. Schonwalder (2002)] which mentioned various The central object which operated by almost all client functions open source SNMP library/tools for different languages. is the “SNMP session”. To query a remote SNMP peer, a session On the other side, the relationship between Common Lisp and object should be created first. ASN.1/SNMP haven’t been studied enough before. There’re some As SNMP protocol has three versions (SNMPv1, SNMPv2c similarities between ASN.1 and Common Lisp. First, the most and SNMPv3), correspondingly, we have three session classes: important ASN.1 aggregate type SEQUENCE can be directly mapped v1-session, v2c-session and v3-session. The entry API of to Common Lisp lists, the both are generalized lists which could client-side SNMP is the function snmp:open-session, which cre- contain any object. Second, ASN.1 lexical tokens like multi-line ates a new SNMP session: strings, comments, and the number representation are almost the snmp:open-session (host &key port version community same as those in Common Lisp. Later will show, by making some user auth priv) necessary changes to CL readtables, the Lisp reader could directly read ASN.1 definitions into Lisp tokens. For SNMP itself, there’re 2.1.1 SNMPv1 and SNMPv2c also some connection between its design and Lisp, especially the To create a SNMPv1 or SNMPv2c session, only keywords port, design of “GetNextRequestPDU” [14], it’s just like the Common version and community are needed. Suppose we have a SNMP Lisp function cdr and later will show that the implementation of server whose host name is "binghe-debian.local", which is this PDU has almost just used the function cdr. running a Net-SNMP agent on default port 161, its SNMP commu- For Common Lisp, before 2007, two SNMP projects have been nity is , and the SNMP protocol is SNMPv2c, then the 3 "public" in existence. Simon Leinen’s SYSMAN is the first Lisp-SNMP so- following form will create a new session and assign it to a variable lution which supports client side SNMPv1/SNMPv2c and server s1: side agent on Symbolics Lisp Machine. It’s a pure lisp implemen- tation, but is not being maintained anymore, and doesn’t support > (setf s1 (snmp:open-session "binghe-debian.local" the new protocol SNMPv3. During 2006, Larry Valkama wrote two :port 161 SNMP client packages 4, both of which are not pure lisp: one is a :version :v2c FFI wrapper to Net-SNMP library, and the other works by captur- :community "public")) ing outputs of Net-SNMP’s common-line utilities. #
2 preparing all OID instances before the actual query work would > (snmp:with-open-session increase the performance. The function asn.1:oid is used for this (s "binghe-debian.local" translation: :version :v3 :user "readonly" :auth ’(:md5 "ABCDEFGHABCDEFGH")) > (asn.1:oid "sysName.0") (snmp:snmp-get s "sysDescr.0")) #
3 (|ifOperStatus| :type integer) cast (0.0.0.0) address. At current stage, no access control9 is (|ifLastChange| :type |TimeTicks|) implemented and only SNMPv1/SNMPv2c are supported. We can ... use the SNMP client API to query it: (|ifSpecific| :type object-id))) > (setf snmp:*default-snmp-port* 8161) These code could be compiled and loaded with SNMP package, and 8161 dynamic loading MIB files should be possible: most Common Lisp platform supports defining new CLOS classes even after delivery. > (snmp:snmp-get "localhost" "sysDescr.0") Once the structure of MIB tables are known, rest work will be quite "LispWorks Personal Edition 5.1.1 on easy. A query on all interfaces information is like this: binghe-mac.people.163.org" Here we changed the default SNMP port to make things easier. Or > (snmp:snmp-select "ifTable" we can use command-line utilities from Net-SNMP project: :from "binghe-debian.local") (#
Above function will open a new Lisp thread which acts as a SNMP 9 The access control protocol used by SNMP is called View-based Access server. By default, the SNMP server listens on port 8161 and wild- Control Model (VACM) [13].
4 LispWorks 5.1.1 on binghe-debian.local To use above two macros for user-defined MIB nodes, named OID nodes must be defined first, like above “sysDescr” or “sysORUp- The agent parameter in above snmp:def-scalar-variable Time”. There are two ways to achieve the goal: define a MIB file in form is used to refer to current SNMP agent instance, which can be ASN.1 syntax and use the ASN.1 compiler from ASN.1 package to used to access the status of current agent. For example: translate it into LISP source code, or directly write the Lisp version (def-scalar-variable "snmpInPkts" (agent) of the MIB definition: (counter32 (slot-value agent ’in-pkts))) (defoid |lispFeatureName| (|lispFeatureEntry| 2) When “snmpInPkts.0” is queried, the slot value in-pkts of current (:type ’object-type) agent instance will be coerced into ASN.1 Counter32 type and 10 (:syntax ’|DisplayString|) returned. (:max-access ’|read-only|) A MIB Table can be defined as per column. For example, to (:status ’|current|) define a column from “sysORUpTime.1” to “sysORUpTime.9”, we (:description have three ways: "The string name of each element in *features*.")) (def-listy-mib-table "sysORUpTime" (agent ids) (if (null ids) At compile-time, above definitions then will be translated into ’((1) (2) (3) (4) (5) (6) (7) (8) (9)) following form: (timeticks 0))) (IN-PACKAGE "ASN.1/LISP-MIB") (def-listy-mib-table "sysORUpTime" (agent ids) (if (null ids) (PROGN ’(1 2 3 4 5 6 7 8 9) (DEFVAR |lispFeatureName| (timeticks 0))) (OR (ENSURE-OID |lispFeatureEntry| 2) (MAKE-INSTANCE ’OBJECT-ID (def-listy-mib-table "sysORUpTime" (agent ids) :NAME ’|lispFeatureName| (if (null ids) :VALUE 2 9 :PARENT |lispFeatureEntry| (timeticks 0))) :MODULE *CURRENT-MODULE* :TYPE ’OBJECT-TYPE The ids parameter means the rest OID components when a :SYNTAX ’|DisplayString| query gets to current base OID (“sysORUpTime” here). You can :MAX-ACCESS ’|read-only| treat the snmp:def-listy-mib-table body as an ordinary func- :STATUS ’|current| tion body. When it’s called by an ids argument as nil, it should :DESCRIPTION return all its valid children to the SNMP agent. A list ’((1) "The string name of each element in *features*."))) (2) (3) (4) (5) (6) (7) (8) (9)) means each valid rest (EVAL-WHEN (:LOAD-TOPLEVEL :EXECUTE) OID has only one element. For the first child, it’s just the num- (ASN.1::REGISTER-OID ber “1”. When a child has rest OID as only one element, the (SYMBOL-NAME ’|lispFeatureName|) long list can be simplified into ’(1 2 3 4 5 6 7 8 9), which ’|lispFeatureName|))) just means “sysORUpTime.1”, “sysORUpTime.2”, ... “sysORUp- Time.9”. And, when all the children have a single number and they The low-level function snmp:register-variable is used by are consistent (from 1 to N), the list can be again simplified into snmp:def-scalar-variable and snmp:def-listy-mib-table. just one number “9” which also means from 1 to 9, then (1) to Above definitions for “sysDescr” will be macro-expanded into: (9). For dynamic MIB tables, just let the form (as a function) returns (IN-PACKAGE "SNMP") an dynamic list when ids given nil will work, like this one: (PROGN (def-listy-mib-table "lispFeatureName" (agent ids) (DEFUN |ASN.1/SNMPv2-MIB|::|sysDescr| (let* ((features *features*) (AGENT &OPTIONAL #:G1290) (number-of-features (DECLARE (IGNORABLE AGENT)) (list-length features))) (IF (NULL #:G1290) (if (null ids) 0 number-of-features (FORMAT NIL (when (plusp (car ids)) "~A ~A on ~A" (->string (nth (mod (1- (car ids)) (LISP-IMPLEMENTATION-TYPE) number-of-features) (LISP-IMPLEMENTATION-VERSION) features)))))) (MACHINE-INSTANCE)))) (EVAL-WHEN (:LOAD-TOPLEVEL :EXECUTE) Above “lispFeatureName” can return all elements of *features* (REGISTER-VARIABLE in current Lisp system as ASN.1 OCTET STRING. Every time it’s (OID "sysDescr") called, the number-of-features will be calculated. It’s not quite #’|ASN.1/SNMPv2-MIB|::|sysDescr|))) optimized here. If you want faster reply, the list count progress should be defined outside of the function and as a cache to the ac- Besides, snmp:register-variable has some additional key- tual value, and a separate thread may be used to update all these words, which can be used explicitly to define MIB nodes in SNMP parameter values on schedule. agent other than the default. It’s possible to run multiple different SNMP agents simultaneously, but more codes are needed. You even 10 This variable has’t been actually used in current version. cannot use snmp:enable-snmp-service here.
5 3. LISP-MIB lisp (31609) common-lisp (1) Though just registering an OID node or sub-tree in SNMP server lispSystem (1) will fit the goal for querying information from remote SNMP peers, lispImplementationType (1) if there’s no coordination on places, conflict would happen and in- lispImplementationVersion (2) formation defined by different SNMP vendors would be impossible lispLongSiteName (3) to live together. SNMP community spend so much time on how to lispShortSiteName (4) define a common framework to hold all variables from SNMP ven- lispMachineInstance (5) dors, that is the MIB (Management Information Base)[15]. lispMachineType (6) Another side: a SNMP server running in Lisp image should lispMachineVersion (7) be possible to reply the status of Lisp system itself, for example, lispSoftwareType (8) the most basically, implementation type and version, which can lispSoftwareVersion (9) be returned by standard functions. ANSI Common Lisp has also lispInternalRealTime (10) defined some status functions of the Lisp system itself (i.e. the lispInternalRunTime (11) internal run time and real time), useful constants (i.e. internal- lispInternalTimeUnitsPerSecond (12) time-units-per-second), and special variables (*read-eval*, lispUniversalTime (13) *print-circle*, ...) All these information plus implementation- lispFeatureTable (14) specific data maybe useful to monitor and just query from outside lispPackageTable (15) world. For popular Lisp packages and some small applications lispModuleTable (16) which have their own status and parameters, the requirement for lispConstants (2) MIB sub-tree should also be considered. lispMostPositiveShortFloat (1) There’s one place in MIB tree which just is left for SNMP lispLeastPositiveShortFloat (2) vendors: the “enterprises” node11. Since there’s no Lisp-related 12 lispLeastPositiveNormalizedShortFloat (3) MIB registered before, A new enterprise number from IANA has ... been registered: 31609 (lisp), which allocated to the LISP-MIB. lispPackages (3) The root of LISP-MIB is “enterprises.lisp” (31609). Its two cl-net-snmp (1) children are “common-lisp” and “scheme”. clNetSnmpObjects (1) In “common-lisp” node, there’re four common children at clNetSnmpEnumerations (2) present: clNetSnmpAgentOIDs (1) • lispSystem, the summary information of current Lisp system. clNetSnmpAgent (1) • clNetSnmpAgentLispWorks (5) lispConstants, constants of limits of number-types. clNetSnmpAgentCMUCL (6) • lispPackages, information store for lisp packages (utilities). ... • lispApplications, information store for lisp applications. cl-http (2) ... Other children of “common-lisp” node are reserved for Common lispApplications (4) Lisp implementations. Implementation-specific variables should be lispworks (5) put there. cmucl (6) The framework of LISP-MIB13 is shown in Figure 1. sbcl (7) clozure (8) 4. Implementation details allegro (9) scl (10) 4.1 Portable UDP Networking ... There’s few portable UDP networking packages in Common Lisp scheme (2) community, partly because UDP applications is rare. One UNIX derived systems, the IOlib 14 package is a good choice for portable Figure 1. LISP-MIB networking: it exports the POSIX compatibility layer through CFFI 15 and has a high-level networking package (net.sockets) and a I/O multiplex package (io.multiplex). However, due to its heavily USOCKET is much simpler than IOlib. It tries to use network- dependence on foreign function interface (FFI) and C code, it will ing APIs which each supported CL implementations already have, be a bit hard to deliver applications into single standalone execu- and add foreign functions (as Lisp code) through FFI interface tions on commercial Common Lisp platforms such as LispWorks. of their own when necessary. So there’s no dependency on CFFI 16 After some investigation, the USOCKET project was been chosen and any other C code (except on ECL, its FFI interface need to extend the support on UDP/IP, because USOCKET already has a C code as embeddable). The USOCKET project also has a high- very nice networking API framework. level wait-for-input function which work in front of UNIX system call select() or other similar funtions, so users can use 11 iso.org.dod.internet.private.enterprises (OID: 1.3.6.1.4.1) wait-for-input) to swap multiple UDP messages from multiple 12 http://www.iana.org/assignments/enterprise-numbers sockets simultaneously in one thread. 13 The MIB definition of LISP-MIB and other LISP-*-MIBs in An USOCKET-UDP 17 sub-project has been written for the ASN.1 can be found in CL-NET-SNMP’s Subversion repository: SNMP package, it implements additional API which is suggested https://cl-net-snmp.svn.sourceforge.net/svnroot/cl-net- by Erik Huelsmann, the USOCKET maintainer. The new functions snmp/snmp/trunk/asn1/lisp socket-send and socket-receive can be used to operate on 14 http://common-lisp.net/project/iolib a new class of socket called datagram-usocket. USOCKET-UDP 15 http://common-lisp.net/project/cffi 16 http://common-lisp.net/project/usocket 17 http://common-lisp.net/projects/cl-net-snmp/usocket.html
6 Table 1. ASN.1 to Common Lisp Type Mapping 4.2.1 BER support ASN.1 Type Common Lisp Type The BER (Basic Encoding Rule) [3] is essential to implement OBJECT IDENTIFIER ASN.1:OBJECT-ID SNMP because it makes the connection between ASN.1 object INTEGER CL:INTEGER and actual networking packets. BER encodes every ASN.1 ob- NULL CL:NULL ject into three parts: type, length and value (TLV). The cor- SEQUENCE CL:SEQUENCE responding API funtions for BER support in ASN.1 package OCTET STRING CL:STRING are asn.1:ber-encode and asn.1:ber-decode. The function IPADDRESS ASN.1:IPADDRESS asn.1:ber-encode accepts any Lisp object and try to encode it COUNTER32 ASN.1:COUNTER32 into a vector of octets according to BER, and asn.1:ber-decode COUNTER64 ASN.1:COUNTER64 accepts a sequence of octets or any octet stream and try to de- GAUGE ASN.1:GAUGE code into correspond Lisp object. For example, an integer 10000 TIMETICKS ASN.1:TIMETICKS can be encoded into four bytes: 2, 2, 39 and 16, of which the first OPAQUE ASN.1:OPAQUE “2” means ASN.1 type INTEGER, the second “2” means following part has two bytes, and 39 and 16 mean the actual value is 10000 (39 ∗ 256 + 16 = 10000): depends on USOCKET 0.4.x, with the first 0.4.0 released on Oct 28, > (asn.1:ber-encode 10000) 2008. Erik also accepted me to the USOCKET team, which the next #(2 2 39 16) major release will contain the UDP support. Another issue in UDP network programming is that user code > (asn.1:ber-decode #(2 2 39 16)) may deal with packet loss, because UDP is not reliable. A simple 10000 way to handle it is used by Net-SNMP project: define a maximum retry time and a timeout value, and resend messages on timeout. Another typical example is the encoding of an ASN.1 SEQUENCE. CL-NET-SNMP adopted a more complicated model, it used an “auto This type is usually used to implement structure in other languages. retransmit” approach [4] which usually used in TCP networking: The elements of an ASN.1 SEQUENCE can be anything include the timeout value is not fixed but calculated by actual message SEQUENCE. For example, a sequence which contains another se- round-trip time (RTT). The maximum retry time is still a fix num- quence which contains an integer 100, a string “abc”, and a NULL ber, as the timeout value being a range (default is 2 60 seconds). A data can be expressed into #(#(100 "abc" nil)) in Common new high-level socket-sync function has been defined to do this Lisp according to our language mapping design. It can be encoded automatically. and decoded correctly: > (asn.1:ber-encode #(#(100 "abc" nil))) 4.2 ASN.1 to Common Lisp language mapping #(48 12 48 10 2 1 100 4 3 97 98 99 5 0) ASN.1 (Abstract Syntax Notation One) [2] is an international stan- dard which aims at specifying data used in telecommunication > (asn.1:ber-decode *) protocols. For more details on ASN.1 and its history, see Olivier #(#(100 "abc" NIL)) Dubuisson’s famous book [1]. The type byte of sequence is 48. Three elements in inner se- SNMP highly depends on ASN.1: SNMP MIB (Management quence can be seen as encoded bytes: #(2 1 100) (integer 100), Information Base) [15] is full defined in SMI (Structure Manage- #(4 3 97 98 99) (string "abc"), and #(5 0) (nil). ment Information) language, a subset of ASN.1; The most ba- Both ASN.1:BER-ENCODE and ASN.1:BER-DECODE are CLOS- sic data type in SNMP, object identifier (OID), is just a standard based generic functions. ASN.1:BER-ENCODE dispatches on Com- ASN.1 type; all data in SNMP message are enclosed as an ASN.1 mon Lisp types, for example the INTEGER: SEQUENCE which is then encoded by BER (Basic Encode Rule) as one of encoding/decoding methods for ASN.1. (defmethod ber-encode ((value integer)) In ASN.1 package, the ASN.1 SEQUENCE type is generally (multiple-value-bind (v l) mapped to Common Lisp sequence, which has two subtypes: (ber-encode-integer value) vector and list. There’s only one exception: the empty ASN.1 (concatenate ’vector SEQUENCE is mapped into empty vector #() instead of nil, the (ber-encode-type 0 0 +asn-integer+) empty list. That’s because nil is already mapped to ASN.1 type (ber-encode-length l) NULL, which is also the only valid element of this type. v))) There’re other ASN.1 primitive types such as all kinds of strings The method (METHOD ASN.1:BER-ENCODE (INTEGER)) gen- and numbers which are used by SNMP and they’re mapped into erates a vector containing type bytes, length bytes and encoding correspond Common Lisp types. Table 1 shows most of these type bytes of the integer. When decoding on integers, generic function mapping the ASN.1 package currently supports. Some ASN.1 types 18 ASN.1:BER-DECODE accepts sequences or streams which contain are mapped into CLOS classes. data, and then call ASN.1:BER-DECODE-VALUE which dispatches In current released CL-NET-SNMP versions, ASN.1 module is on keywords (:integer here): not supported. That is: all MIB definitions are compiled into Com- mon Lisp code in package ASN.1. This may cause symbol clash. (defmethod ber-decode ((value sequence)) Recently this issue has been solved, now ASN.1 modules are di- (let ((stream (make-instance ’ber-stream rectly mapped into Common Lisp packages as their original mod- :sequence value))) ule names. (ber-decode stream)))
18 In CL-NET-SNMP 5.x, strings and integers are just mapped into CL types (defmethod ber-decode ((stream stream)) string and integer. To support SMI textual conventions (TC, see [9]), (multiple-value-bind (type type-bytes) more complex mapping is needed. This will be done in next major CL-NET- (ber-decode-type stream) SNMP version. (multiple-value-bind (length length-bytes)
7 Table 2. Different ways to represent OID “sysDescr.0” (defclass object-id (asn.1-type) ((name :type symbol (asn.1:oid "sysDescr.0") :reader oid-name (asn.1:oid "SNMPv2-MIB::sysDescr.0") :initarg :name) (asn.1:oid "system.sysDescr.0") (value :type integer (asn.1:oid "1.3.6.1.2.1.1.1.0") :reader oid-value (asn.1:oid ".1.3.6.1.2.1.1.1.0") :initarg :value) (asn.1:oid "0.1.3.6.1.2.1.1.1.0") (type :type oid-type (asn.1:oid #(1 3 6 1 2 1 1 1 0)) :reader oid-type (asn.1:oid ’(1 3 6 1 2 1 1 1 0)) :initarg :type) (asn.1:oid (list (asn.1:oid "sysDescr") 0)) (syntax :type oid-syntax (asn.1:oid (list |SNMPv2-MIB|::|sysDescr| 0)) :reader oid-syntax :initarg :syntax) (max-access :type access (ber-decode-length stream) :reader oid-max-access (if type :initarg :max-access) (ber-decode-value stream type length) (status :type status ;; When unknown type detected, recover the :reader oid-status ;; whole data into an ASN.1 RAW object. :initarg :status) (ber-decode-value (description :type string stream type :reader oid-description (cons length :initarg :description) (append type-bytes length-bytes))))))) (module :type symbol :reader oid-module (defmethod ber-decode-value ((stream stream) :initarg :module) (type (eql :integer)) (parent :type object-id length) :reader oid-parent (declare (type fixnum length) (ignore type)) :initarg :parent) (ber-decode-integer-value stream length)) (children :type hash-table :accessor oid-children This BER engine in ASN.1 packages is extensible. That’s the :initform (make-hash-table))) biggest difference from other existing BER engines for Common (:documentation "OBJECT IDENTIFIER")) Lisp which can be found in SYSMAN and TRIVIAL-LDAP.The first value returned by asn.1:ber-decode-type comes from a hash- Figure 2. The definition of asn.1:object-id class table asn.1::*ber-dispatch-table*, and all ASN.1 types are registered into this hash-table: Table 3. Internal structure of OBJECT-ID instance (defun install-asn.1-type (type class p/c tags) Slot Value (setf (gethash (list class p/c tags) children #
8 DESCRIPTION 7. Retrieve the variable bindings list from the pdu slot in above "A textual description of the entity. message instances. This value should include the full 8. Generate return values from above variable bindings list. name and version identification of the system’s hardware type, software Though there’re many steps on processing SNMP operations [11], operating-system, the core function, snmp::snmp-request, which do most steps in and networking software." above and it’s quite simple. The source code is shown in Figure 3. ::= { system 1 } In Table 3, the value of slot parent is another OID instance, 5. Future Work which is stored in variable |SNMPv2-MIB|::|system|: There’s still lots of work to do. On ASN.1 side, the SMIv2 Textual Convention (TC) [9] haven’t been implemented. This part of work > (asn.1:oid-parent |SNMPv2-MIB|::|sysDescr|) will give a better representation on strings and numbers used in #
6. Decode the response packet and create a new message instance 20 from the decode result and the old message instance. http://www.msi.co.jp/~fremlin/projects/snmp-async/ 21 http://www.lispworks.com/products/capi.html 19 http://method-combination.net/lisp/ironclad/ 22 http://www.intel.com/design/servers/ipmi/
9 (defmethod snmp-request ((session session) (request symbol) (bindings list) &key context) (when bindings (let ((vb (mapcar #’(lambda (x) (if (consp x) (list (oid (first x)) (second x)) (list (oid x) nil))) bindings))) ;; Get a report first if the session is new created. (when (and (= (version-of session) +snmp-version-3+) (need-report-p session)) (snmp-report session :context context)) (let ((message (make-instance (gethash (type-of session) *session->message*) :session session :context (or context *default-context*) :pdu (make-instance request :variable-bindings vb)))) (let ((reply (send-snmp-message session message))) (when reply (map ’list #’(lambda (x) (coerce x ’list)) (variable-bindings-of (pdu-of reply)))))))))
(defun snmp-get (session bindings &key context) (let ((result (mapcar #’second (snmp-request session ’get-request-pdu bindings :context context)))) (if (consp bindings) result (car result))))
Figure 3. The core SNMP function: snmp-request
• GBBopen Project23 (Daniel D. Corkill), [8] K. McCloghrie, D. Perkins, J. Schonwalder, et al. Structure of Management Information Version 2 (SMIv2). RFC 2578, April 1999. • IRONCLAD Project (Nathan Froyd), • 24 [9] K. McCloghrie, D. Perkins, J. Schonwalder, et al. Textual Conven- LispWorks . tions for SMIv2. RFC 2579, April 1999. Special thanks to Mathematical Systems Inc. (MSI) 25 for the [10] D. Harrington, R. Presuhn and B. Wijnen. An Architecture adoption of CL-NET-SNMP in their enterprise projects, with bugfix for Describing Simple Network Management Protocol (SNMP) and new feature suggestion. Management Frameworks. RFC 3411, December 2002. [11] J. Case, D. Harrington, R. Presuhn and B. Wijnen. Message Processing and Dispatching for the Simple Network Management References Protocol (SNMP) RFC 3412, December 2002. [J. Schonwalder (2002)] J. Schonwalder. Evolution of Open Source SNMP [12] U. Blumenthal and B. Wijnen. User-based Security Model (USM) for Tools. In Proc. SANE 2002 Conference, April 29 2002. version 3 of the Simple Network Management Protocol (SNMPv3). RFC 3414, December 2002. [W. Yeong (1990)] W. Yeong. SNMP Query Language. Technical Report 90-03-31-1, Performance Systems International, March 1990. [13] B. Wijnen, R. Presuhn, and K. McCloghrie. View-based Access Control Model (VACM) for the Simple Network Management [1] O. Dubuisson. ASN.1—Communication between heterogeneous Protocol (SNMP). RFC 3415, December 2002. systems. Morgan Kaufmann, 2000. [14] R. Presuhn, J. Case, K. McCloghrie, M .Rose and S. Waldbusser. [2] Abstract Syntax Notation One (ASN.1) Specification of Basic Version 2 of the Protocol Operations for the Simple Network Notation. ITU-T Rec. X.680 (2002) — ISO/IEC 8824-1:2002. Management Protocol (SNMP). RFC 3416, December 2002. [3] ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), [15] R. Presuhn, J. Case, K. McCloghrie, M. Rose, and S. Waldbusser. Canonical Encoding Rules (CER) and Distinguished Encoding Rules Management Information Base (MIB) for the Simple Network (DER). ITU-T Rec. X.690 (2002) — ISO/IEC 8825-1:2002. Management Protocol (SNMP). RFC 3418, December 2002. [4] V. Jacobson. Congestion avoidance and control. In Proceedings of [16] K. Zeilenga, Ed. Lightweight Directory Access Protocol (LDAP): SIGCOMM ’88, 1988. Technical Specification Road Map RFC 4510, June 2006. [5] J. Postel. User Datagram Protocol. RFC 768, 28 August 1980. [6] J. Case, M. Fedor, M. Schoffstall and J. Davin. A Simple Network Management Protocol (SNMP). RFC 1157, May 1990. [7] J. Case, K. McCloghrie, M. Rose, and S. Waldbusser. Introduction to Community-based SNMPv2. RFC 1901, January 1996.
23 http://gbbopen.org 24 http://www.lispworks.com 25 http://www.msi.co.jp
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