SnmpKit.SnmpSim.BulkOperations (snmpkit v0.6.4)

Efficient GETBULK implementation for SNMPv2c. Handles non-repeaters, max-repetitions, and response size management.

GETBULK is a powerful SNMP operation that retrieves multiple variables in a single request. It's particularly useful for retrieving large tables like interface statistics.

Algorithm

  1. Process first N variable bindings as non-repeaters (like GETNEXT)
  2. For remaining variable bindings, repeat up to max-repetitions times
  3. Respect UDP packet size limits (typically 1472 bytes for Ethernet)
  4. Return tooBig error if response would exceed limits

Summary

Functions

estimate_response_size(varbinds)

Calculate estimated response size for a list of variable bindings. Used for response size management.

handle_bulk_request(oid_tree, non_repeaters, max_repetitions, varbinds)

Handle a GETBULK request with proper non-repeaters and max-repetitions processing.

optimize_bulk_response(results, max_size \\ 1400)

Optimize bulk response to fit within UDP packet size limits. Estimates response size and truncates if necessary.

process_interface_table(oid_tree, table_oid, max_repetitions)

Process an interface table bulk request efficiently. Optimized for common SNMP table walking operations.

Functions

estimate_response_size(varbinds)

Calculate estimated response size for a list of variable bindings. Used for response size management.

Examples

size = SnmpKit.SnmpSim.BulkOperations.estimate_response_size(varbinds)

handle_bulk_request(oid_tree, non_repeaters, max_repetitions, varbinds)

Handle a GETBULK request with proper non-repeaters and max-repetitions processing.

Parameters

  • oid_tree: The OID tree to query
  • non_repeaters: Number of variables to treat as non-repeating (GETNEXT only)
  • max_repetitions: Maximum number of repetitions for repeating variables
  • varbinds: List of starting OIDs for the bulk operation

Returns

  • {:ok, result_varbinds}: Successful bulk operation results
  • {:error, :too_big}: Response would exceed UDP size limits
  • {:error, reason}: Other error conditions

Examples

varbinds = [{"1.3.6.1.2.1.2.2.1.1", nil}, {"1.3.6.1.2.1.2.2.1.2", nil}]
{:ok, results} = SnmpKit.SnmpSim.BulkOperations.handle_bulk_request(
  tree, 0, 10, varbinds
)

optimize_bulk_response(results, max_size \\ 1400)

Optimize bulk response to fit within UDP packet size limits. Estimates response size and truncates if necessary.

Parameters

  • results: List of {oid, value, behavior} tuples
  • max_size: Maximum response size in bytes (default: 1400)

Returns

  • {:ok, optimized_results}: Results that fit within size limit
  • {:error, :too_big}: Even minimal response exceeds size limit

Examples

{:ok, optimized} = SnmpKit.SnmpSim.BulkOperations.optimize_bulk_response(results, 1400)

process_interface_table(oid_tree, table_oid, max_repetitions)

Process an interface table bulk request efficiently. Optimized for common SNMP table walking operations.

Examples

{:ok, results} = SnmpKit.SnmpSim.BulkOperations.process_interface_table(
  tree, "1.3.6.1.2.1.2.2.1", 10
)