Skip to content

Commit

Permalink
Merge pull request #6 from gapitio/feature/snmp-get-by-block
Browse files Browse the repository at this point in the history 
Feature/snmp get by block
  • Loading branch information
@sverre
sverre authored Mar 18, 2022
2 parents e89c02e + a610e30 commit 48a5789
Showing 1 changed file with 93 additions and 42 deletions.
135 changes: 93 additions & 42 deletions gapit-snmp.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -256,6 +256,7 @@ module.exports = function (RED) {

function GapitSnmpNode(config) {
RED.nodes.createNode(this, config);
this.blockTuningSteps = 10;
this.config = config;
this.multi_device_separator = ";";
this.version = (config.version === "2c") ? snmp.Version2c : snmp.Version1;
Expand Down Expand Up @@ -427,7 +428,6 @@ module.exports = function (RED) {
msg.db_tags = node.db_tags;
msg.custom_tags = node.custom_tags;
msg.tagname_device_name = node.tagname_device_name;
msg.varbinds = varbinds;
msg.oid_value_map = oid_value_map;
msg.gapit_results = gapit_results;
node.send(msg);
Expand Down Expand Up @@ -588,65 +588,116 @@ module.exports = function (RED) {
return oids;
}

this.snmpGetIndividualOids = function (host, community, oids, msg) {
// Query OIDs individually
// Workaround for SNMPv1 queries failing if one or more OIDS
// don't exist.

msg.v1QueryCount = oids.length;
msg.v1ResponseCount = 0;
msg.v1Varbinds = Array();
for (const oid of oids) {
console.debug(`SNMPv1 single-OID query for '${oid}'`);
getSession(host, community, node.version, node.timeout).get([oid], function (singleQueryError, singleQueryVarbinds) {
msg.v1ResponseCount += 1;
console.debug(`Got SNMPv1 single-OID response #${msg.v1ResponseCount} of ${msg.v1QueryCount}`);
if (singleQueryError) {
if((singleQueryError.name == "RequestFailedError") && (singleQueryError.status == snmp.ErrorStatus.NoSuchName)) {
node.warn(`SNMPv1 single-OID query: OID '${oid}' is not present`);
node.addNonExistentOid(oid);
}
else {
node.error(`SNMPv1 single-OID request error: ${singleQueryError.toString()}`);
}
}
else {
console.debug(`Got result for SNMPv1 single-OID query for OID '${oid}'`);
msg.v1Varbinds.push(singleQueryVarbinds[0]);
}
if (msg.v1ResponseCount === msg.v1QueryCount) {
console.debug("Got responses for all SNMPv1 single-OID queries, processing results");
node.processVarbinds(msg, msg.v1Varbinds);
}
});

node.persistNonExistentOids();
}
}

this.snmpGet = function (host, community, oids, msg) {
getSession(host, community, node.version, node.timeout).get(oids, function (error, varbinds) {
this.tuneSnmpBlockSize = function (host, community, oids, msg, blockSize) {
getSession(host, community, node.version, node.timeout).get(oids.slice(0, blockSize), function (error, varbinds) {
if (error) {
// error object has .name, .message and, optionally, .status
// error.status is only set for RequestFailed, so check
// that it's this error before checking the value of .status
if((error.name == "RequestFailedError") && (error.status == snmp.ErrorStatus.NoSuchName)) {
if ((error.name == "RequestFailedError") && (error.status == snmp.ErrorStatus.TooBig)) {
// Adjust blockSize down one level, try again.
blockSize = blockSize - node.blockTuningSteps;
node.warn(`Still tooBig, trying again with ${blockSize} OIDs`);
node.tuneSnmpBlockSize(host, community, oids, msg, blockSize);
}
else if ((error.name == "RequestFailedError") && (error.status == snmp.ErrorStatus.NoSuchName)) {
// As soon as tooBig is no longer triggered, this error
// may occur.
//
// SNMPv1 NoSuchName
// A single "missing" OID causes an SNMPv1 query to fail,
// query OIDs one by one as a workaround
node.warn("SNMPv1 NoSuchName, will query all OIDs individually");
node.snmpGetIndividualOids(host, community, oids, msg);
node.getBlockSize = 1;
node.snmpGet(host, community, oids, msg);
}
else {
node.error("Request error: " + error.toString(), msg);
}
}
else {
node.processVarbinds(msg, varbinds);
console.info(`Found working block size to work around SNMP tooBig error: ${blockSize} OIDs`);
node.getBlockSize = blockSize;
node.snmpGet(host, community, oids, msg);
}
});
}

this.snmpGet = function (host, community, oids, msg) {
let blockSize = 0;
if (node.getBlockSize !== undefined) {
blockSize = node.getBlockSize;
console.debug(`Querying OIDs in blocks of ${blockSize}, total number of OIDs is ${oids.length}`);
// For testing, remove always-failing (in simulator) oid from list.
// let simFailingOidIndex = oids.indexOf("1.3.6.1.4.1.534.1.9.7.0.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2.1.2")
// if (simFailingOidIndex != -1) {
// oids.splice(simFailingOidIndex, 1);
// }
}
else {
blockSize = oids.length;
console.debug("Querying all OIDs in a single request");
}

msg.varbinds = Array();
msg.totalBlockResponseCount = 0;

for (let blockStart = 0; blockStart < oids.length; blockStart=blockStart+blockSize) {
let oidBlock = oids.slice(blockStart, blockStart+blockSize);
getSession(host, community, node.version, node.timeout).get(oidBlock, function (error, blockVarbinds) {
msg.totalBlockResponseCount += oidBlock.length;
if (error) {
// error object has .name, .message and, optionally, .status
// error.status is only set for RequestFailed, so check
// that it's this error before checking the value of .status
if ((error.name == "RequestFailedError") && (error.status == snmp.ErrorStatus.NoSuchName)) {
// SNMPv1 NoSuchName
if (blockSize > 1) {
// A single "missing" OID causes an SNMPv1 query to fail,
// query OIDs one by one as a workaround
node.warn("SNMPv1 NoSuchName, will query all OIDs individually");
node.getBlockSize = 1;
node.snmpGet(host, community, oids, msg);
}
else {
node.warn(`SNMPv1 single-OID query: OID '${oidBlock[0]}' is not present`);
node.addNonExistentOid(oidBlock[0]);
}
}
else if ((error.name == "RequestFailedError") && (error.status == snmp.ErrorStatus.TooBig)) {
// SNMP tooBig -- too many OIDs for a single request
// The request must be broken into several smaller requests.
// Set an initial bulk size, then let tuneSnmpBlockSize()
// handle further adjustments.
let blockSize = oids.length - node.blockTuningSteps - (oids.length % node.blockTuningSteps);
node.warn(`SNMP tooBig error, divide into multiple requests for blocks of OIDS, first attempt: ${blockSize} OIDs`);
node.tuneSnmpBlockSize(host, community, oids, msg, blockSize);
}
else {
node.error("Request error: " + error.toString(), msg);
}
}
else {
// add results for this block to msg.varbinds
msg.varbinds.push(... blockVarbinds);
}

// if all queries have returned, and at least one had data, process
if (msg.totalBlockResponseCount === oids.length && msg.varbinds.length > 0) {
if (blockSize != oids.length) {
console.debug("Got results for all OID block queries, processing");
// clear 1-block if set (SNMPv1 NoSuchName)
if (node.getBlockSize !== undefined && node.getBlockSize == 1) {
console.debug("Clearing get block size of 1, assumed set for SNMPv1 NoSuchName");
delete(node.getBlockSize);
}
}
node.processVarbinds(msg, msg.varbinds);
}
});
}
}

this.on("input", function (msg) {
node.readNonExistentOids();

Expand Down

0 comments on commit 48a5789

Please sign in to comment.