1BER(3) User Contributed Perl Documentation BER(3)
2
6 BER - Basic Encoding Rules (BER) of Abstract Syntax Notation One
7 (ASN.1)
8
10 use BER;
11 $encoded = encode_sequence (encode_int (123), encode_string ("foo"));
12 ($i, $s) = decode_by_template ($encoded, "%{%i%s");
13 # $i will now be 123, $s the string "foo".
14
16 This is a simple library to encode and decode data using the Basic
17 Encoding Rules (BER) of Abstract Syntax Notation One (ASN.1). It does
18 not claim to be a complete implementation of the standard, but
19 implements enough of the BER standard to encode and decode SNMP
20 messages.
21
23 $pretty_print_timeticks (default: 1)
24 If non-zero (the default), "pretty_print" will convert TimeTicks to
25 "human readable" strings containing days, hours, minutes and seconds.
26 If the variable is zero, "pretty_print" will simply return an unsigned
28 integer representing hundredths of seconds. If you prefer this, bind
29 $pretty_print_timeticks to zero.
30 $errmsg - error message from last failed operation.
32 When they encounter errors, the routines in this module will generally
33 return "undef") and leave an informative error message in $errmsg).
34
36 encode_int_0() - encode the integer 0.
37 This is functionally identical to encode_int(0).
38 encode_int() - encode an integer using the generic "integer" type tag.
40 encode_uinteger32() - encode an integer using the SNMP UInteger32 tag.
41 encode_counter32() - encode an integer using the SNMP Counter32 tag.
42 encode_counter64() - encode an integer using the SNMP Counter64 tag.
43 encode_gauge32() - encode an integer using the SNMP Gauge32 tag.
44 encode_oid() - encode an object ID, passed as a list of sub-IDs.
45 $encoded = encode_oid (1,3,6,1,...);
46 encode_null() - encode a null object.
48 This is used e.g. in binding lists for variables that don't have a
49 value (yet)
50 encode_sequence()
52 encode_tagged_sequence()
53 $encoded = encode_sequence (encoded1, encoded2, ...);
54 $encoded = encode_tagged_sequence (tag, encoded1, encoded2, ...);
55 Take already encoded values, and extend them to an encoded sequence.
57 "encoded_sequence" uses the generic sequence tag, while with
58 "encode_tagged_sequence" you can specify your own tag.
59 encode_string() - encode a Perl string as an OCTET STRING.
61 encode_ip_address() - encode an IPv4 address.
62 This can either be passed as a four-octet sequence in network byte
63 order, or as a text string in dotted-quad notation, e.g. "192.0.2.234".
64 encode_timeticks() - encode an integer as a "TimeTicks" object.
66 The integer should count hundredths of a second since the epoch defined
67 by "sysUpTime.0".
68 pretty_print() - convert an encoded byte sequence into human-readable form.
70 This function can be extended by registering pretty-printing methods
71 for specific type codes. Most BER type codes used in SNMP already have
72 such methods pre-registered by default. See "register_pretty_printer"
73 for how new methods can be added.
74 hex_string() - convert OCTET STRING to hexadecimal notation.
76 hex_string_of_type() - convert octet string to hex, and check type against
77 given tag.
78 decode_by_template() - decode complex object according to a template.
79 ($var1, ...) = decode_by_template ($pdu, $template, ...);
80 The template can contain various %X directives. Some directives
82 consume additional arguments following the template itself. Most
83 directives will cause values to be returned. The values are returned
84 as a sequence in the order of the directives that generated them.
85 %{ - decode sequence.
87 This doesn't assign any return value, just checks and skips the
88 tag/length fields of the sequence. By default, the tag should be
89 the generic sequence tag, but a tag can also be specified in the
90 directive. The directive can either specify the tag as a prefix,
91 e.g. "%99{" will require a sequence tag of 99, or if the directive
92 is given as "%*{", the tag will be taken from the next argument.
93 %s - decode string
95 %i - decode integer
96 %u - decode unsigned integer
97 %O - decode Object ID (OID)
98 %A - decode IPv4 address
99 %@ - assigns the remaining undecoded part of the PDU to the next return
100 value.
101 decode_sequence() - Split sequence into components.
103 ($first, $rest) = decode_sequence ($pdu);
104 Checks whether the PDU has a sequence type tag and a plausible length
106 field. Splits the initial element off the list, and returns both this
107 and the remainder of the PDU.
108 register_pretty_printer() - register pretty-printing methods for typecodes.
110 This function takes a hashref that specifies functions to call when the
111 specified value type is being printed. It returns the number of
112 functions that were registered.
113
115 Created by: Simon Leinen <simon.leinen@switch.ch>
116 Contributions and fixes by:
118 Andrzej Tobola <san@iem.pw.edu.pl>: Added long String decode
120 Tobias Oetiker <tobi@oetiker.ch>: Added 5 Byte Integer decode ...
121 Dave Rand <dlr@Bungi.com>: Added "SysUpTime" decode
122 Philippe Simonet <sip00@vg.swissptt.ch>: Support larger subids
123 Yufang HU <yhu@casc.com>: Support even larger subids
124 Mike Mitchell <Mike.Mitchell@sas.com>: New generalized encode_int()
125 Mike Diehn <mdiehn@mindspring.net>: encode_ip_address()
126 Rik Hoorelbeke <rik.hoorelbeke@pandora.be>: encode_oid() fix
127 Brett T Warden <wardenb@eluminant.com>: pretty "UInteger32"
128 Bert Driehuis <driehuis@playbeing.org>: Handle SNMPv2 exception codes
129 Jakob Ilves (/IlvJa) <jakob.ilves@oracle.com>: PDU decoding
130 Jan Kasprzak <kas@informatics.muni.cz>: Fix for PDU syntax check
131 Milen Pavlov <milen@batmbg.com>: Recognize variant length for ints
132
134 Copyright (c) 1995-2009, Simon Leinen.
135 This program is free software; you can redistribute it under the
137 "Artistic License 2.0" included in this distribution (file "Artistic").
138perl v5.38.0 2023-07-21 BER(3)