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Handle single-OID queries in snmpGet method
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For "SNMPv1 NoSuchName", use the regular snmpGet method with a block
size of 1. Modified handling of NoSuchName error when blockSize == 1.

Keep track of the number of OIDs results have been returned for, the
final length of msg.varbinds is less than oids.length if some OIDs
can't be found. Call processVarbinds when the number of results matches
the number of OIDs, regardless of whether this particular (final) query
yielded data.

Removed snmpGetIndividualOids method.
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Sverre Johan Tøvik committed Mar 17, 2022
1 parent 028a46f commit a610e30
Showing 1 changed file with 25 additions and 46 deletions.
71 changes: 25 additions & 46 deletions gapit-snmp.js
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Original file line number Diff line number Diff line change
Expand Up @@ -588,42 +588,6 @@ 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.tuneSnmpBlockSize = function (host, community, oids, msg, blockSize) {
getSession(host, community, node.version, node.timeout).get(oids.slice(0, blockSize), function (error, varbinds) {
if (error) {
Expand All @@ -644,7 +608,8 @@ module.exports = function (RED) {
// 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);
Expand Down Expand Up @@ -675,20 +640,29 @@ module.exports = function (RED) {
}

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
// 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);
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
Expand All @@ -706,14 +680,19 @@ module.exports = function (RED) {
else {
// add results for this block to msg.varbinds
msg.varbinds.push(... blockVarbinds);
}

// if all varbinds have been returned, process
if (msg.varbinds.length === oids.length) {
if (blockSize != oids.length) {
console.debug("Got results for all OID block queries, processing");
// 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);
}
node.processVarbinds(msg, msg.varbinds);
}
});
}
Expand Down

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