snmp
Interface functions to the SNMP toolkit
The module snmp
contains interface functions to the
SNMP toolkit.
Common Data Types
The following data-types are used in the functions below:
-
datetime() = {date(), time()}
See calendar for more info.
Functions
config() -> ok | {error, Reason}
A simple interactive configuration tool. Simple configuration files can be generated, but more complex configurations still have to be edited manually.
The tool is a textual based tool that asks some questions
and generates sys.config
and *.conf
files.
Note that if the application shall support version 3, then the crypto app must be started before running this function (password generation).
Note also that some of the configuration files for the agent and manager share the same names. This means that they have to be stored in different directories!
start() -> ok | {error, Reason}
start(Type) -> ok | {error, Reason}
Type = start_type()
start_agent() -> ok | {error, Reason}
start_agent(Type) -> ok | {error, Reason}
Type = start_type()
The SNMP application consists of several entities, of which the agent is one. This function starts the agent entity of the application.
Note that the only way to actually start the agent in this way is
to add the agent related config after starting the application (e.g
it cannot be part of the normal application config; sys.config).
This is done by calling:
application:set_env(snmp, agent, Conf)
.
The default value for Type
is normal
.
start_manager() -> ok | {error, Reason}
start_manager(Type) -> ok | {error, Reason}
Type = start_type()
The SNMP application consists of several entities, of which the manager is one. This function starts the manager entity of the application.
Note that the only way to actually start the manager in this way is
to add the manager related config after starting the application (e.g
it cannot be part of the normal application config; sys.config).
This is done by calling:
application:set_env(snmp, manager, Conf)
.
The default value for Type
is normal
.
date_and_time() -> DateAndTime
DateAndTime = [int()]
Returns current date and time as the data type DateAndTime, as specified in RFC1903. This is an OCTET STRING.
date_and_time_to_universal_time_dst(DateAndTime) -> [utc()]
DateAndTime = [int()]
utc() = {{Y,Mo,D},{H,M,S}}
Converts a DateAndTime list to a list of possible universal time(s). The universal time value on the same format as defined in calendar(3).
date_and_time_to_string(DateAndTime) -> string()
date_and_time_to_string(DateAndTime, Validate) -> string()
DateAndTime = [int()]
Validate = fun(Kind, Data) -> boolean()
Converts a DateAndTime list to a printable string, according to the DISPLAY-HINT definition in RFC2579.
The validation fun, Validate
, allows for a more "flexible"
validation of the DateAndTime
argument. Whenever the data
is found to not follow RFC2579, the fun is called to allow a more
"lax" validation.
See the validate_date_and_time/2
function for more info on the Validate
fun.
date_and_time_to_string2(DateAndTime) -> string()
DateAndTime = [int()]
Converts a DateAndTime list to a printable string, according to the DISPLAY-HINT definition in RFC2579, with the extension that it also allows the values "hours from UTC" = 14 together with "minutes from UTC" = 0.
local_time_to_date_and_time_dst(Local) -> [DateAndTime]
Local = {{Y,Mo,D},{H,M,S}}
DateAndTime = [int()]
Converts a local time value to a list of possible DateAndTime list(s). The local time value on the same format as defined in calendar(3).
universal_time_to_date_and_time(UTC) -> DateAndTime
UTC = {{Y,Mo,D},{H,M,S}}
DateAndTime = [int()]
Converts a universal time value to a DateAndTime list. The universal time value on the same format as defined in calendar(3).
validate_date_and_time(DateAndTime) -> bool()
validate_date_and_time(DateAndTime, Validate) -> bool()
DateAndTime = term()
Validate = fun(Kind, Data) -> boolean()
Checks if DateAndTime
is a correct DateAndTime
value, as specified in RFC2579. This function can be used in
instrumentation functions to validate a DateAndTime value.
The validation fun, Validate
, allows for a more "flexible"
validation of the DateAndTime
argument. Whenever the data
is found to not follow RFC2579, the fun is called to allow a more
"lax" validation.
The input to the validation fun looks like this:
Kind Data -------------- ---------------------- year {Year1, Year2} month Month day Day hour Hour minute Minute seconds Seconds deci_seconds DeciSeconds diff [Sign, Hour, Minute] valid_date {Year, Month, Day}
passwd2localized_key(Alg, Passwd, EngineID) -> Key
Alg = algorithm()
algorithm() = md5 | sha
Passwd = string()
EngineID = string()
Key = list()
Generates a key that can be used as an authentication or privacy key using MD5 och SHA. The key is localized for EngineID.
octet_string_to_bits(S) -> Val
Val = bits()
Utility function for converting a value of type
OCTET-STRING
to BITS
.
bits_to_octet_string(B) -> Val
Val = octet_string()
Utility function for converting a value of type BITS
to OCTET-STRING
.
read_mib(FileName) -> {ok, mib()} | {error, Reason}
FileName = string()
mib() = #mib{}
Reason = term()
Read a compiled mib.
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Start) -> ok | {error, Reason}
log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Start, Stop) -> ok | {error, Reason}
LogDir = string()
Mibs = [MibName]
OutFile = string()
MibName = string()
LogName = string()
LogFile = string()
Start = Stop = null | datetime() | {local_time,datetime()} | {universal_time,datetime()}
Reason = term()
Converts an Audit Trail Log to a readable text file, where each item has a trailing TAB character, and any TAB character in the body of an item has been replaced by ESC TAB.
The function can be used on a running system, or by copying the entire log directory and calling this function. SNMP must be running in order to provide MIB information.
LogDir
is the name of the directory where the audit
trail log is stored.
Mibs
is a list of Mibs to be used. The function uses
the information in the Mibs to convert for example object
identifiers to their symbolic name.
OutFile
is the name of the generated text-file.
LogName
is the name of the log,
LogFile
is the name of the log file.
Start
is the start (first) date and time from which
log events will be converted and
Stop
is the stop (last) date and time to which log
events will be converted.
The format of an audit trail log text item is as follows:
Tag Addr - Community [TimeStamp] Vsn
PDU
where Tag
is request
, response
,
report
, trap
or inform
; Addr is
IP:Port
(or comma space separated list of such);
Community
is the community parameter (SNMP version
v1 and v2), or SecLevel:"AuthEngineID":"UserName"
(SNMP v3); TimeStamp
is a date and time stamp,
and Vsn
is the SNMP version. PDU
is a textual
version of the protocol data unit. There is a new line
between Vsn
and PDU
.
change_log_size(LogName, NewSize) -> ok | {error, Reason}
LogName = string()
NewSize = {MaxBytes, MaxFiles}
MaxBytes = integer()
MaxFiles = integer()
Reason = term()
Changes the log size of the Audit Trail Log. The application must be configured to use the audit trail log function. Please refer to disk_log(3) in Kernel Reference Manual for a description of how to change the log size.
The change is permanent, as long as the log is not deleted. That means, the log size is remembered across reboots.
print_version_info() -> void()
print_version_info(Prefix) -> void()
Prefix = string() | integer()
Utility function(s) to produce a formatted printout of the versions
info generated by the versions1
function
This is the same as doing, e.g.:
{ok, V} = snmp:versions1(), snmp:print_versions(V).
versions1() -> {ok, Info} | {error, Reason}
versions2() -> {ok, Info} | {error, Reason}
Info = [info()]
info() = term()
Reason = term()
Utility functions used to retrieve some system and application info.
The difference between the two functions is in how they get
the modules to check. versions1
uses the app-file and
versions2
uses the function application:get_key
.
print_versions(VersionInfo) -> void()
print_versions(Prefix, VersionInfo) -> void()
VersionInfo = [version_info()]
version_info() = term()
Prefix = string() | integer()
Utility function to produce a formatted printout of the versions
info generated by the versions1
and versions2
functions
Example:
{ok, V} = snmp:versions1(), snmp:print_versions(V).
enable_trace() -> void()
Starts a dbg tracer that prints trace events to stdout (using plain io:format after a minor formatting).
disable_trace() -> void()
Stop the tracer.
set_trace(Targets) -> void()
Targets = target() | targets()
target() = module()
module() = atom()
targets() = [target() | {target(), target_options()}]
target_options() = [target_option()]
target_option() = {return_trace, boolean()} | {scope, scope()}
scope() = all_functions | exported_functions | function_name() | {function_name(), function_arity()}
function_name() = atom()
function_arity() = integer() >= 0
This function is used to set up default trace on function(s) for the given module or modules. The scope of the trace will be all exported functions (both the call info and the return value). Timestamp info will also be included.
reset_trace(Targets) -> void()
Targets = module() | modules()
modules() = [module()]
module() = atom()
This function is used to reset (disable) trace for the given module(s).
set_trace(Targets, Opts) -> void()
Targets = target() | targets()
target() = module()
module() = atom()
targets() = [target() | {target(), target_options()}]
target_options() = [target_option()]
target_option() = {return_trace, boolean()} | {scope, scope()}
scope() = all_functions | exported_functions | function_name() | {function_name(), function_arity()}
function_name() = atom()
function_arity() = integer() >= 0
Opts = disable | trace_options()
trace_options() = [trace_option()]
trace_option() = {timestamp, boolean()} | target_option()
This function is used to set up trace on function(s) for the given module or modules.
The example below sets up trace on the exported functions (default)
of module snmp_generic
and all functions of module
snmp_generic_mnesia
. With return values (which is default)
and timestamps in both cases (which is also default):
snmp:enable_trace(), snmp:set_trace([snmp_generic, {snmp_generic_mnesia, [{scope, all_functions}]}]), . . . snmp:set_trace(snmp_generic, disable), . . . snmp:disable_trace(),
See Also
calendar(3)
- config/0
- start/0
- start/1
- start_agent/0
- start_agent/1
- start_manager/0
- start_manager/1
- date_and_time/0
- date_and_time_to_universal_time_dst/1
- date_and_time_to_string/1
- date_and_time_to_string/2
- date_and_time_to_string2/1
- local_time_to_date_and_time_dst/1
- universal_time_to_date_and_time/1
- validate_date_and_time/1
- validate_date_and_time/2
- passwd2localized_key/3
- octet_string_to_bits/1
- bits_to_octet_string/1
- read_mib/1
- log_to_txt/5
- log_to_txt/6
- log_to_txt/7
- change_log_size/2
- print_version_info/0
- print_version_info/1
- versions1/0
- versions2/0
- print_versions/1
- print_versions/2
- enable_trace/0
- disable_trace/0
- set_trace/1
- reset_trace/1
- set_trace/2