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4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Convert::BER::XS ':all'; |
7 | use Convert::BER::XS ':all'; |
8 | |
8 | |
9 | my $ber = ber_decode $buf |
9 | my $ber = ber_decode $buf, $Convert::BER::XS::SNMP_PROFILE |
10 | or die "unable to decode SNMP message"; |
10 | or die "unable to decode SNMP message"; |
11 | |
11 | |
12 | # The above results in a data structure consisting of |
12 | # The above results in a data structure consisting of |
13 | # (class, tag, # constructed, data) |
13 | # (class, tag, # constructed, data) |
14 | # tuples. Below is such a message, SNMPv1 trap |
14 | # tuples. Below is such a message, SNMPv1 trap |
15 | # with a Cisco mac change notification. |
15 | # with a Cisco mac change notification. |
16 | # Did you know that Cisco is in the news almost |
16 | # Did you know that Cisco is in the news almost |
17 | # every week because # of some backdoor password |
17 | # every week because of some backdoor password |
18 | # or other extremely stupid security bug? |
18 | # or other extremely stupid security bug? |
19 | |
19 | |
20 | [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, |
20 | [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, |
21 | [ |
21 | [ |
22 | [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1 |
22 | [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 0 ], # snmp version 1 |
23 | [ ASN_UNIVERSAL, 4, 0, "public" ], # community |
23 | [ ASN_UNIVERSAL, 4, 0, "public" ], # community |
24 | [ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU |
24 | [ ASN_CONTEXT, 4, 1, # CHOICE, constructed - trap PDU |
25 | [ |
25 | [ |
26 | [ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid |
26 | [ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.2" ], # enterprise oid |
27 | [ ASN_APPLICATION, 0, 0, "\x0a\x00\x00\x01" ], # SNMP IpAddress, 10.0.0.1 |
27 | [ ASN_APPLICATION, SNMP_IPADDRESS, 0, "10.0.0.1" ], # SNMP IpAddress |
28 | [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 6 ], # generic trap |
28 | [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 6 ], # generic trap |
29 | [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 1 ], # specific trap |
29 | [ ASN_UNIVERSAL, ASN_INTEGER32, 0, 1 ], # specific trap |
30 | [ ASN_APPLICATION, ASN_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks |
30 | [ ASN_APPLICATION, SNMP_TIMETICKS, 0, 1817903850 ], # SNMP TimeTicks |
31 | [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist |
31 | [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # the varbindlist |
32 | [ |
32 | [ |
33 | [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair |
33 | [ ASN_UNIVERSAL, ASN_SEQUENCE, 1, # a single varbind, "key value" pair |
34 | [ |
34 | [ |
35 | [ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ], |
35 | [ ASN_UNIVERSAL, ASN_OBJECT_IDENTIFIER, 0, "1.3.6.1.4.1.9.9.215.1.1.8.1.2.1" ], |
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62 | ) { |
62 | ) { |
63 | ... and so on |
63 | ... and so on |
64 | |
64 | |
65 | # finally, let's encode it again and hope it results in the same bit pattern |
65 | # finally, let's encode it again and hope it results in the same bit pattern |
66 | |
66 | |
67 | my $buf = ber_encode $ber; |
67 | my $buf = ber_encode $ber, $Convert::BER::XS::SNMP_PROFILE; |
68 | |
68 | |
69 | =head1 DESCRIPTION |
69 | =head1 DESCRIPTION |
70 | |
70 | |
71 | WARNING: Before release 1.0, the API is not considered stable in any way. |
71 | WARNING: Before release 1.0, the API is not considered stable in any way. |
72 | |
72 | |
73 | This module implements a I<very> low level BER/DER en-/decoder. |
73 | This module implements a I<very> low level BER/DER en-/decoder. |
74 | |
74 | |
75 | If is tuned for low memory and high speed, while still maintaining some |
75 | It is tuned for low memory and high speed, while still maintaining some |
76 | level of user-friendlyness. |
76 | level of user-friendlyness. |
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77 | |
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78 | =head2 EXPORT TAGS AND CONSTANTS |
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79 | |
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80 | By default this module doesn't export any symbols, but if you don't want |
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81 | to break your keyboard, editor or eyesight with extremely long names, I |
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82 | recommend importing the C<:all> tag. Still, you can selectively import |
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83 | things. |
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84 | |
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85 | =over |
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86 | |
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87 | =item C<:all> |
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88 | |
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89 | All of the below. Really. Recommended for at least first steps, or if you |
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90 | don't care about a few kilobytes of wasted memory (and namespace). |
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91 | |
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92 | =item C<:const> |
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93 | |
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94 | All of the strictly ASN.1-related constants defined by this module, the |
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95 | same as C<:const_asn :const_index>. Notably, this does not contain |
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96 | C<:const_ber_type> and C<:const_snmp>. |
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97 | |
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98 | A good set to get everything you need to decode and match BER data would be |
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99 | C<:decode :const>. |
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100 | |
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101 | =item C<:const_index> |
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102 | |
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103 | The BER tuple array index constants: |
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104 | |
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105 | BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA |
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106 | |
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107 | =item C<:const_asn> |
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108 | |
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109 | ASN class values (these are C<0>, C<1>, C<2> and C<3>, respectively - |
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110 | exactly thw two topmost bits from the identifier octet shifted 6 bits to |
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111 | the right): |
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112 | |
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113 | ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE |
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114 | |
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115 | ASN tag values (some of which are aliases, such as C<ASN_OID>). Their |
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116 | numerical value corresponds exactly to the numbers used in BER/X.690. |
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117 | |
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118 | ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER |
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119 | ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED |
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120 | ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING |
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121 | ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING |
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122 | ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING |
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123 | ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING |
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124 | |
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125 | =item C<:const_ber_type> |
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126 | |
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127 | The BER type constants, explained in the PROFILES section. |
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128 | |
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129 | BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT |
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130 | BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL |
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131 | BER_TYPE_IPADDRESS BER_TYPE_CROAK |
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132 | |
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133 | =item C<:const_snmp> |
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134 | |
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135 | Constants only relevant to SNMP. These are the tag values used by SNMP in |
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136 | the C<ASN_APPLICATION> namespace and have the exact numerical value as in |
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137 | BER/RFC 2578. |
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138 | |
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139 | SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64 |
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140 | |
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141 | =item C<:decode> |
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142 | |
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143 | C<ber_decode> and the match helper functions: |
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144 | |
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145 | ber_decode ber_is ber_is_seq ber_is_i32 ber_is_oid |
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146 | |
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147 | =item C<:encode> |
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148 | |
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149 | C<ber_encode> and the construction helper functions: |
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150 | |
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151 | ber_encode ber_i32 |
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152 | |
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153 | =back |
77 | |
154 | |
78 | =head2 ASN.1/BER/DER/... BASICS |
155 | =head2 ASN.1/BER/DER/... BASICS |
79 | |
156 | |
80 | ASN.1 is a strange language that can be used to describe protocols and |
157 | ASN.1 is a strange language that can be used to describe protocols and |
81 | data structures. It supports various mappings to JSON, XML, but most |
158 | data structures. It supports various mappings to JSON, XML, but most |
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92 | and also have a flag that says whether a value consists of subvalues (is |
169 | and also have a flag that says whether a value consists of subvalues (is |
93 | "constructed") or not (is "primitive"). |
170 | "constructed") or not (is "primitive"). |
94 | |
171 | |
95 | Tags are simple integers, and ASN.1 defines a somewhat weird assortment of |
172 | Tags are simple integers, and ASN.1 defines a somewhat weird assortment of |
96 | those - for example, you have 32 bit signed integers and 16(!) different |
173 | those - for example, you have 32 bit signed integers and 16(!) different |
97 | string types, but there is no unsigned32 type for example. Different |
174 | string types, but there is no Unsigned32 type for example. Different |
98 | applications work around this in different ways, for example, SNMP defines |
175 | applications work around this in different ways, for example, SNMP defines |
99 | application-specific Gauge32, Counter32 and Unsigned32, which are mapped |
176 | application-specific Gauge32, Counter32 and Unsigned32, which are mapped |
100 | to two different tags: you can distinguish between Counter32 and the |
177 | to two different tags: you can distinguish between Counter32 and the |
101 | others, but not between Gause32 and Unsigned32, without the ASN.1 schema. |
178 | others, but not between Gause32 and Unsigned32, without the ASN.1 schema. |
102 | |
179 | |
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106 | |
183 | |
107 | This module represents every BER value as a 4-element tuple (actually an |
184 | This module represents every BER value as a 4-element tuple (actually an |
108 | array-reference): |
185 | array-reference): |
109 | |
186 | |
110 | [CLASS, TAG, CONSTRUCTED, DATA] |
187 | [CLASS, TAG, CONSTRUCTED, DATA] |
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188 | |
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189 | For example: |
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190 | |
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191 | [ASN_UNIVERSAL, ASN_INTEGER32, 0, 177] # the integer 177 |
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192 | [ASN_UNIVERSAL, ASN_OCTET_STRING, 0, "john"] # the string "john" |
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193 | [ASN_UNIVERSAL, ASN_OID, 0, "1.3.6.133"] # some OID |
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194 | [ASN_UNIVERSAL, ASN_SEQUENCE, 1, [ [ASN_UNIVERSAL... # a sequencE |
111 | |
195 | |
112 | To avoid non-descriptive hardcoded array index numbers, this module |
196 | To avoid non-descriptive hardcoded array index numbers, this module |
113 | defines symbolic constants to access these members: C<BER_CLASS>, |
197 | defines symbolic constants to access these members: C<BER_CLASS>, |
114 | C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>. |
198 | C<BER_TAG>, C<BER_CONSTRUCTED> and C<BER_DATA>. |
115 | |
199 | |
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294 | $VERSION = 0.8; |
378 | $VERSION = 0.8; |
295 | XSLoader::load __PACKAGE__, $VERSION; |
379 | XSLoader::load __PACKAGE__, $VERSION; |
296 | } |
380 | } |
297 | |
381 | |
298 | our %EXPORT_TAGS = ( |
382 | our %EXPORT_TAGS = ( |
299 | const => [qw( |
383 | const_index => [qw( |
300 | BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA |
384 | BER_CLASS BER_TAG BER_CONSTRUCTED BER_DATA |
301 | |
385 | )], |
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386 | const_asn => [qw( |
302 | ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER |
387 | ASN_BOOLEAN ASN_INTEGER32 ASN_BIT_STRING ASN_OCTET_STRING ASN_NULL ASN_OBJECT_IDENTIFIER |
303 | ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED |
388 | ASN_OBJECT_DESCRIPTOR ASN_OID ASN_EXTERNAL ASN_REAL ASN_SEQUENCE ASN_ENUMERATED |
304 | ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING |
389 | ASN_EMBEDDED_PDV ASN_UTF8_STRING ASN_RELATIVE_OID ASN_SET ASN_NUMERIC_STRING |
305 | ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING |
390 | ASN_PRINTABLE_STRING ASN_TELETEX_STRING ASN_T61_STRING ASN_VIDEOTEX_STRING ASN_IA5_STRING |
306 | ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING |
391 | ASN_ASCII_STRING ASN_UTC_TIME ASN_GENERALIZED_TIME ASN_GRAPHIC_STRING ASN_VISIBLE_STRING |
307 | ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING |
392 | ASN_ISO646_STRING ASN_GENERAL_STRING ASN_UNIVERSAL_STRING ASN_CHARACTER_STRING ASN_BMP_STRING |
308 | |
393 | |
309 | ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE |
394 | ASN_UNIVERSAL ASN_APPLICATION ASN_CONTEXT ASN_PRIVATE |
310 | |
395 | )], |
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396 | const_ber_type => [qw( |
311 | BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT |
397 | BER_TYPE_BYTES BER_TYPE_UTF8 BER_TYPE_UCS2 BER_TYPE_UCS4 BER_TYPE_INT |
312 | BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL |
398 | BER_TYPE_OID BER_TYPE_RELOID BER_TYPE_NULL BER_TYPE_BOOL BER_TYPE_REAL |
313 | BER_TYPE_IPADDRESS BER_TYPE_CROAK |
399 | BER_TYPE_IPADDRESS BER_TYPE_CROAK |
314 | )], |
400 | )], |
315 | const_snmp => [qw( |
401 | const_snmp => [qw( |
316 | SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64 |
402 | SNMP_IPADDRESS SNMP_COUNTER32 SNMP_UNSIGNED32 SNMP_TIMETICKS SNMP_OPAQUE SNMP_COUNTER64 |
317 | )], |
403 | )], |
318 | encode => [qw( |
404 | decode => [qw( |
319 | ber_decode |
405 | ber_decode |
320 | ber_is ber_is_seq ber_is_i32 ber_is_oid |
406 | ber_is ber_is_seq ber_is_i32 ber_is_oid |
321 | )], |
407 | )], |
322 | decode => [qw( |
408 | encode => [qw( |
323 | ber_encode |
409 | ber_encode |
324 | ber_i32 |
410 | ber_i32 |
325 | )], |
411 | )], |
326 | ); |
412 | ); |
327 | |
413 | |
328 | our @EXPORT_OK = map @$_, values %EXPORT_TAGS; |
414 | our @EXPORT_OK = map @$_, values %EXPORT_TAGS; |
329 | |
415 | |
330 | $EXPORT_TAGS{all} = \@EXPORT_OK; |
416 | $EXPORT_TAGS{all} = \@EXPORT_OK; |
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417 | $EXPORT_TAGS{const} = [map @{ $EXPORT_TAGS{$_} }, qw(const_index const_asn)]; |
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418 | use Data::Dump; ddx \%EXPORT_TAGS; |
331 | |
419 | |
332 | =head1 PROFILES |
420 | =head1 PROFILES |
333 | |
421 | |
334 | While any BER data can be correctly encoded and decoded out of the box, it |
422 | While any BER data can be correctly encoded and decoded out of the box, it |
335 | can be inconvenient to have to manually decode some values into a "better" |
423 | can be inconvenient to have to manually decode some values into a "better" |
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480 | =cut |
568 | =cut |
481 | |
569 | |
482 | our $DEFAULT_PROFILE = new Convert::BER::XS::Profile; |
570 | our $DEFAULT_PROFILE = new Convert::BER::XS::Profile; |
483 | our $SNMP_PROFILE = new Convert::BER::XS::Profile; |
571 | our $SNMP_PROFILE = new Convert::BER::XS::Profile; |
484 | |
572 | |
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573 | # additional SNMP application types |
485 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); |
574 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_IPADDRESS , BER_TYPE_IPADDRESS); |
486 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); |
575 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_COUNTER32 , BER_TYPE_INT); |
487 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); |
576 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_UNSIGNED32, BER_TYPE_INT); |
488 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); |
577 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_TIMETICKS , BER_TYPE_INT); |
489 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS); |
578 | $SNMP_PROFILE->set (ASN_APPLICATION, SNMP_OPAQUE , BER_TYPE_IPADDRESS); |
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491 | |
580 | |
492 | $DEFAULT_PROFILE->_set_default; |
581 | $DEFAULT_PROFILE->_set_default; |
493 | |
582 | |
494 | 1; |
583 | 1; |
495 | |
584 | |
496 | =head2 LIMITATIONS |
585 | =head2 LIMITATIONS/NOTES |
497 | |
586 | |
498 | This module can only en-/decode 64 bit signed and unsigned integers, and |
587 | This module can only en-/decode 64 bit signed and unsigned integers, and |
499 | only when your perl supports those. |
588 | only when your perl supports those. |
500 | |
589 | |
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590 | This module does not generally care about ranges, i.e. it will happily |
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591 | de-/encode 64 bit integers into an C<ASN_INTEGER32> value, or a negative |
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592 | number into an C<SNMP_COUNTER64>. |
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593 | |
501 | OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is |
594 | OBJECT IDENTIFIEERs cannot have unlimited length, although the limit is |
502 | much larger than e.g. the one imposed by SNMP or other protocols. |
595 | much larger than e.g. the one imposed by SNMP or other protocols,a nd is |
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596 | about 4kB. |
503 | |
597 | |
504 | REAL values are not supported and will croak. |
598 | REAL values are not supported and will currently croak. |
505 | |
599 | |
506 | This module has undergone little to no testing so far. |
600 | This module has undergone little to no testing so far. |
507 | |
601 | |
508 | =head2 ITHREADS SUPPORT |
602 | =head2 ITHREADS SUPPORT |
509 | |
603 | |