View Source snmpa_mpd (snmp v5.15)
Message Processing and Dispatch module for the SNMP agent
The module snmpa_mpd
implements the version independent Message Processing and
Dispatch functionality in SNMP for the agent. It is supposed to be used from a
Network Interface process (Definition of Agent Net if).
DATA TYPES
See the data types in snmpa_conf
.
Summary
Functions
discarded_pdu(Variable) -> void()
Equivalent to generate_msg/6
generate_msg(Vsn, NoteStore, Pdu, MsgData, LocalEngineID, To) -> {ok, PacketsAndAddresses} | {discarded, Reason}
generate_response_msg(Vsn, RePdu, Type, ACMData, LocalEngineID, Log) -> {ok, Packet} | {discarded, Reason}
init(Vsns) -> mpd_state()
process_packet(Packet, From, LocalEngineID, State, NoteStore, Log) -> {ok, Vsn, Pdu, PduMS, ACMData} | {discarded, Reason} | {discovery, DiscoPacket}
process_taddrs(TDests) -> Dests
Functions
discarded_pdu(Variable) -> void()
Increments the variable associated with a discarded pdu. This function can be
used when the net_if process receives a discarded_pdu
message from the agent.
Equivalent to generate_msg/6
generate_msg(Vsn, NoteStore, Pdu, MsgData, LocalEngineID, To) -> {ok, PacketsAndAddresses} | {discarded, Reason}
Generates a possibly encrypted request packet to be sent to the network.
MsgData
is the message specific data used in the SNMP message. This value is
received in a send_pdu
or
send_pdu_req
message from the agent. In
SNMPv1 and SNMPv2c, this message data is the community string. In SNMPv3, it is
the context information.
To
is a list of destination addresses and their corresponding security
parameters. This value is received in the same message from the agent and then
transformed through process_taddrs
before
passed to this function.
Note
Note that the use of the LocalEngineID argument is only intended for special cases, if the agent is to "emulate" multiple EngineIDs! By default, the agent uses the value of
SnmpEngineID
(see SNMP-FRAMEWORK-MIB).
generate_response_msg(Vsn, RePdu, Type, ACMData, Log)
View Source (since OTP R14B)Equivalent to generate_response_msg/6
generate_response_msg(Vsn, RePdu, Type, ACMData, LocalEngineID, Log) -> {ok, Packet} | {discarded, Reason}
Generates a possibly encrypted response packet to be sent to the network. Type
is the #pdu.type
of the original request.
Note
Note that the use of the LocalEngineID argument is only intended for special cases, if the agent is to "emulate" multiple EngineIDs! By default, the agent uses the value of
SnmpEngineID
(see SNMP-FRAMEWORK-MIB).
init(Vsns) -> mpd_state()
This function can be called from the net_if process at start-up. The options list defines which versions to use.
It also initializes some SNMP counters.
process_packet(Packet, From, State, NoteStore, Log)
View Source (since OTP 17.3,OTP R14B)Equivalent to process_packet/6
process_packet(Packet, From, LocalEngineID, State, NoteStore, Log) -> {ok, Vsn, Pdu, PduMS, ACMData} | {discarded, Reason} | {discovery, DiscoPacket}
Processes an incoming packet. Performs authentication and decryption as necessary. The return values should be passed to the agent.
Note
Note that the use of the LocalEngineID argument is only intended for special cases, if the agent is to "emulate" multiple EngineIDs! By default, the agent uses the value of
SnmpEngineID
(see SNMP-FRAMEWORK-MIB).
process_taddrs(TDests) -> Dests
Transforms addresses from internal MIB format to one more useful to Agent Net if.
See also generate_msg
.