# snmp

### MODULE

snmp

### MODULE SUMMARY

Interface functions to the SNMP toolkit

### DESCRIPTION

The module `snmp` contains interface functions to the SNMP toolkit.

### Common Data Types

The following datatypes are used in the functions below:

- `oid() = [byte()]`

The `oid()` type is used to represent an ASN.1 OBJECT IDENTIFIER.

### EXPORTS

`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}`

Types:

`Type = start_type()`

Starts the SNMP application.

See application for more info.

`start_agent() -> ok | {error, Reason}`
`start_agent(Type) -> ok | {error, Reason}`

Types:

`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}`

Types:

`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`.

`versions1() -> {ok, Info} | {error, Reason}`
`versions2() -> {ok, Info} | {error, Reason}`

Types:

`Info = [info()]`
`info() = term()`
`Reason = term()`

Utility functions used to retreive 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_version_info() -> void()`
`print_version_info(Prefix) -> void()`

Types:

`Prefix = string() | integer()`

Utility function(s) to produce a formated 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).

`print_versions(VersionInfo) -> void()`
`print_versions(Prefix, VersionInfo) -> void()`

Types:

`VersionInfo = [version_info()]`
`version_info() = term()`
`Prefix = string() | integer()`

Utility function to produce a formated printout of the versions info generated by the `versions1` and `versions2` functions

Example:

               {ok, V} = snmp:versions1(),
               snmp:print_versions(V).

`date_and_time() -> DateAndTime`

Types:

`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()]`

Types:

`DateAndTime = [int()]`
`utc() = {{Y,Mo,D},{H,M,S}}`

Converts a DateAndTime list to a list of possible universal time(s). The unversal time value on the same format as defined in calendar(3).

`date_and_time_to_string(DateAndTime) -> string()`

Types:

`DateAndTime = [int()]`

Converts a DateAndTime list to a printable string, according to the DISPLAY-HINT definition in RFC1903.

`local_time_to_date_and_time_dst(Local) -> [DateAndTime]`

Types:

`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`

Types:

`UTC = {{Y,Mo,D},{H,M,S}}`
`DateAndTime = [int()]`

Converts a universal time value to a DateAndTime list. The unversal time value on the same format as defined in calendar(3).

`validate_date_and_time(DateAndTime) -> bool()`

Types:

`DateAndTime = term()`

Checks if `DateAndTime` is a correct DateAndTime value, as specified in RFC1903. This function can be used in instrumentation functions to validate a DateAndTime value.

`passwd2localized_key(Alg, Passwd, EngineID) -> Key`

Types:

`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.

`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}`

Types:

`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 textfile. `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}`

Types:

`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 remebered across reboots.

### See Also

calendar(3)

### AUTHORS

Martin Björklund - support@erlang.ericsson.se
Klas Eriksson - support@erlang.ericsson.se

snmp 4.9.3
Copyright © 1991-2007 Ericsson AB