net-ping
This module implements ICMP Echo (ping) support for Node.js.
This module is installed using node package manager (npm):
npm install net-ping
It is loaded using the require()
function:
var ping = require ("net-ping");
A ping session can then be created to ping or trace route to many hosts:
var session = ping.createSession ();
session.pingHost (target, function (error, target) {
if (error)
console.log (target + ": " + error.toString ());
else
console.log (target + ": Alive");
});
Network Protocol Support
This module supports IPv4 using the ICMP, and IPv6 using the ICMPv6.
Error Handling
Each request exposed by this module requires one or more mandatory callback
functions. Callback functions are typically provided an error
argument.
All errors are sub-classes of the Error
class. For timed out errors the
error passed to the callback function will be an instance of the
ping.RequestTimedOutError
class, with the exposed message
attribute set
to Request timed out
.
This makes it easy to determine if a host responded, a time out occurred, or whether an error response was received:
session.pingHost ("1.2.3.4", function (error, target) {
if (error)
if (error instanceof ping.RequestTimedOutError)
console.log (target + ": Not alive");
else
console.log (target + ": " + error.toString ());
else
console.log (target + ": Alive");
});
In addition to the the ping.RequestTimedOutError
class, the following errors
are also exported by this module to wrap ICMP error responses:
DestinationUnreachableError
PacketTooBigError
ParameterProblemError
RedirectReceivedError
SourceQuenchError
TimeExceededError
These errors are typically reported by hosts other than the intended target.
In all cases each class exposes a source
attribute which will specify the
host who reported the error (which could be the intended target). This will
also be included in the errors message
attribute, i.e.:
$ sudo node example/ping-ttl.js 1 192.168.2.10 192.168.2.20 192.168.2.30
192.168.2.10: Alive
192.168.2.20: TimeExceededError: Time exceeded (source=192.168.1.1)
192.168.2.30: Not alive
The Session
class will emit an error
event for any other error not
directly associated with a request. This is typically an instance of the
Error
class with the errors message
attribute specifying the reason.
Packet Size
By default ICMP echo request packets sent by this module are 16 bytes in size. Some implementations cannot cope with such small ICMP echo requests. For example, some implementations will return an ICMP echo reply, but will include an incorrect ICMP checksum.
This module exposes a packetSize
option to the createSession()
method which
specifies how big ICMP echo request packets should be:
var session = ping.createSession ({packetSize: 64});
Round Trip Times
Some callbacks used by methods exposed by this module provide two instances of
the JavaScript Date
class specifying when the first ping was sent for a
request, and when a request completed.
These parameters are typically named sent
and rcvd
, and are provided to
help round trip time calculation.
A request can complete in one of two ways. In the first, a ping response is
received and rcvd - sent
will yield the round trip time for the request in
milliseconds.
In the second, no ping response is received resulting in a request time out.
In this case rcvd - sent
will yield the total time spent waiting for each
retry to timeout if any. For example, if the retries
option to the
createSession()
method was specified as 2
and timeout
as 2000
then
rcvd - sent
will yield more than 6000
milliseconds.
Although this module provides instances of the Date
class to help round trip
time calculation the dates and times represented in each instance should not be
considered 100% accurate.
Environmental conditions can affect when a date and time is actually calculated, e.g. garbage collection introducing a delay or the receipt of many packets at once. There are also a number of functions through which received packets must pass, which can also introduce a slight variable delay.
Throughout development experience has shown that, in general the smaller the round trip time the less accurate it will be - but the information is still useful nonetheless.
Constants
The following sections describe constants exported and used by this module.
ping.NetworkProtocol
This object contains constants which can be used for the networkProtocol
option to the createSession()
function exposed by this module. This option
specifies the IP protocol version to use when creating the raw socket.
The following constants are defined in this object:
IPv4
- IPv4 protocolIPv6
- IPv6 protocol
Using This Module
The Session
class is used to issue ping and trace route requests to many
hosts. This module exports the createSession()
function which is used to
create instances of the Session
class.
ping.createSession ([options])
The createSession()
function instantiates and returns an instance of the
Session
class:
// Default options
var options = {
networkProtocol: ping.NetworkProtocol.IPv4,
packetSize: 16,
retries: 1,
sessionId: (process.pid % 65535),
timeout: 2000,
ttl: 128
};
var session = ping.createSession (options);
The optional options
parameter is an object, and can contain the following
items:
networkProtocol
- Either the constantping.NetworkProtocol.IPv4
or the constantping.NetworkProtocol.IPv6
, defaults to the constantping.NetworkProtocol.IPv4
packetSize
- How many bytes each ICMP echo request packet should be, defaults to16
, if the value specified is less that12
then the value12
will be used (8 bytes are required for the ICMP packet itself, then 4 bytes are required to encode a unique session ID in the request and response packets)retries
- Number of times to re-send a ping requests, defaults to1
sessionId
- A unique ID used to identify request and response packets sent by this instance of theSession
class, valid numbers are in the range of1
to65535
, defaults to the value ofprocess.pid % 65535
timeout
- Number of milliseconds to wait for a response before re-trying or failing, defaults to2000
ttl
- Value to use for the IP header time to live field, defaults to128
After creating the ping Session
object an underlying raw socket will be
created. If the underlying raw socket cannot be opened an exception with be
thrown. The error will be an instance of the Error
class.
Seperate instances of the Session
class must be created for IPv4 and IPv6.
session.on ("close", callback)
The close
event is emitted by the session when the underlying raw socket
is closed.
No arguments are passed to the callback.
The following example prints a message to the console when the underlying raw socket is closed:
session.on ("close", function () {
console.log ("socket closed");
});
session.on ("error", callback)
The error
event is emitted by the session when the underlying raw socket
emits an error.
The following arguments will be passed to the callback
function:
error
- An instance of theError
class, the exposedmessage
attribute will contain a detailed error message.
The following example prints a message to the console when an error occurs with the underlying raw socket, the session is then closed:
session.on ("error", function (error) {
console.log (error.toString ());
session.close ();
});
session.close ()
The close()
method closes the underlying raw socket, and cancels all
outstanding requsts.
The calback function for each outstanding ping requests will be called. The
error parameter will be an instance of the Error
class, and the message
attribute set to Socket forcibly closed
.
The sessoin can be re-used simply by submitting more ping requests, a new raw socket will be created to serve the new ping requests. This is a way in which to clear outstanding requests.
The following example submits a ping request and prints the target which successfully responded first, and then closes the session which will clear the other outstanding ping requests.
var targets = ["1.1.1.1", "2.2.2.2", "3.3.3.3"];
for (var i = 0; i < targets.length; i++) {
session.pingHost (targets[i], function (error, target) {
if (! error) {
console.log (target);
session.close ();
}
});
}
session.getSocket ()
The getSocket()
method returns the underlying raw socket used by the session.
This class is an instance of the Socket
class exposed by the
raw-socket module. This can be used to modify properties of the
raw socket, such as specifying which network interface ICMP messages should be
sent from.
In the following example the network interface from which to send ICMP messages is set:
var raw = require("raw-socket") // Required for access to constants
var level = raw.SocketLevel.SOL_SOCKET
var option = raw.SocketOption.SO_BINDTODEVICE
var iface = Buffer.from("eth0")
session.getSocket().setOption(level, option, iface, iface.length)
session.pingHost (target, callback)
The pingHost()
method sends a ping request to a remote host.
The target
parameter is the dotted quad formatted IP address of the target
host for IPv4 sessions, or the compressed formatted IP address of the target
host for IPv6 sessions.
The callback
function is called once the ping requests is complete. The
following arguments will be passed to the callback
function:
error
- Instance of theError
class or a sub-class, ornull
if no error occurredtarget
- The target parameter as specified in the request still be the target host and NOT the responding gatewaysent
- An instance of theDate
class specifying when the first ping was sent for this request (refer to the Round Trip Time section for more information)rcvd
- An instance of theDate
class specifying when the request completed (refer to the Round Trip Time section for more information)
The following example sends a ping request to a remote host:
var target = "fe80::a00:27ff:fe2a:3427";
session.pingHost (target, function (error, target, sent, rcvd) {
var ms = rcvd - sent;
if (error)
console.log (target + ": " + error.toString ());
else
console.log (target + ": Alive (ms=" + ms + ")");
});
session.traceRoute (target, ttlOrOptions, feedCallback, doneCallback)
The traceRoute()
method provides similar functionality to the trace route
utility typically provided with most networked operating systems.
The target
parameter is the dotted quad formatted IP address of the target
host for IPv4 sessions, or the compressed formatted IP address of the target
host for IPv6 sessions. The optional ttlOrOptions
parameter can be either a
number which specifies the maximum number of hops used by the trace route,
which defaults to the ttl
options parameter as defined by the
createSession()
method, or an object which can contain the following
parameters:
ttl
- The maximum number of hops used by the trace route, defaults to thettl
options parameter as defined by thecreateSession()
methodmaxHopTimeouts
- The maximum number of hop timeouts that should occur, defaults to3
startTtl
- Starting ttl for the trace route, defaults to1
Some hosts do not respond to ping requests when the time to live is 0
, that
is they will not send back an time exceeded error response. Instead of
stopping the trace route at the first time out this method will move on to the
next hop, by increasing the time to live by 1. It will do this 2 times by
default, meaning that a trace route will continue until the target host
responds or at most 3 request time outs are experienced. The maxHopTimeouts
option above can be used to control how many hop timeouts can occur.
Each requst is subject to the retries
and timeout
option parameters to the
createSession()
method. That is, requests will be retried per hop as per
these parameters.
This method will not call a single callback once the trace route is complete.
Instead the feedCallback
function will be called each time a ping response is
received or a time out occurs. The following arguments will be passed to the
feedCallback
function:
error
- Instance of theError
class or a sub-class, ornull
if no error occurredtarget
- The target parameter as specified in the requestttl
- The time to live used in the request which triggered this respinsesent
- An instance of theDate
class specifying when the first ping was sent for this request (refer to the Round Trip Time section for more information)rcvd
- An instance of theDate
class specifying when the request completed (refer to the Round Trip Time section for more information)
Once a ping response has been received from the target, or more than three
request timed out errors are experienced, the doneCallback
function will be
called. The following arguments will be passed to the doneCallback
function:
error
- Instance of theError
class or a sub-class, ornull
if no error occurredtarget
- The target parameter as specified in the request
Once the doneCallback
function has been called the request is complete and
the requestCallback
function will no longer be called.
If the feedCallback
function returns a true value when called the trace route
will stop and the doneCallback
will be called.
The following example initiates a trace route to a remote host:
function doneCb (error, target) {
if (error)
console.log (target + ": " + error.toString ());
else
console.log (target + ": Done");
}
function feedCb (error, target, ttl, sent, rcvd) {
var ms = rcvd - sent;
if (error) {
if (error instanceof ping.TimeExceededError) {
console.log (target + ": " + error.source + " (ttl="
+ ttl + " ms=" + ms +")");
} else {
console.log (target + ": " + error.toString ()
+ " (ttl=" + ttl + " ms=" + ms +")");
}
} else {
console.log (target + ": " + target + " (ttl=" + ttl
+ " ms=" + ms +")");
}
}
session.traceRoute ("192.168.10.10", 10, feedCb, doneCb);
Example Programs
Example programs are included under the modules example
directory.
Bugs & Known Issues
None, yet!
Bug reports should be sent to stephen.vickers.sv@gmail.com.
Changes
Version 1.0.0 - 03/02/2013
- Initial release
Version 1.0.1 - 04/02/2013
- Minor corrections to the README.md
- Add note to README.md about error handling
- Timed out errors are now instances of the
ping.RequestTimedOutError
object
Version 1.0.2 - 11/02/2013
- The RequestTimedOutError class is not being exported
Version 1.1.0 - 13/02/2013
- Support IPv6
Version 1.1.1 - 15/02/2013
- The
ping.Session.close()
method was not undefining the sessions raw socket after closing - Return self from the
pingHost()
method to chain method calls
Version 1.1.2 - 04/03/2013
- Use the
raw.Socket.pauseRecv()
andraw.Socket.resumeRecv()
methods instead of closing a socket when there are no more outstanding requests
Version 1.1.3 - 07/03/2013
- Sessions were limited to sending 65535 ping requests
Version 1.1.4 - 09/04/2013
- Add the
packetSize
option to thecreateSession()
method to specify how many bytes each ICMP echo request packet should be
Version 1.1.5 - 17/05/2013
- Incorrectly parsing ICMP error responses resulting in responses matching the wrong request
- Use a unique session ID per instance of the
Session
class to identify requests and responses sent by a session - Added the (internal)
_debugRequest()
and_debugResponse()
methods, and the_debug
option to thecreateSession()
method - Added example programs
ping-ttl.js
andping6-ttl.js
- Use MIT license instead of GPL
Version 1.1.6 - 17/05/2013
- Session IDs are now 2 bytes (previously 1 byte), and request IDs are also now 2 bytes (previously 3 bytes)
- Each ICMP error response now has an associated error class (e.g. the
Time exceeded
response maps onto theping.TimeExceededError
class) - Call request callbacks with an error when there are no free request IDs because of too many outstanding requests
Version 1.1.7 - 19/05/2013
- Added the
traceRoute()
method - Added the
ttl
option parameter to thecreateSession()
method, and updated the example programsping-ttl.js
andping6-ttl.js
to use it - Response callback for
pingHost()
now includes two instances of theDate
class to specify when a request was sent and a response received
Version 1.1.8 - 01/07/2013
- Use
raw.Socket.createChecksum()
instead of automatic checksum generation
Version 1.1.9 - 01/07/2013
- Use
raw.Socket.writeChecksum()
instead of manually rendering checksums
Version 1.1.10 - 02/04/2014
- Echo requests sent by this module are processed like responses when sent to
the
127.0.0.1
and::1
addresses
Version 1.1.11 - 12/08/2014
- Cannot specify the
retries
parameter for theSession
class as0
- Added example program
ping-retries-0.js
Version 1.1.12 - 22/09/2015
- Host repository on GitHub
Version 1.2.0 - 29/02/2016
- Wrong callback called in the
traceRoute()
method when a session ID cannot be generated - Renamed the optional
ttl
parameter to thetraceRoute()
method tottlOrOptions
, and it is still optional - Permit users to control the number of permitted hop timeouts for the
traceRoute()
method, added themaxHopTimeouts
parameter to thetraceRoute()
methods options - The
traceRoute()
method can start its trace at a higher ttl, added thestartTtl
parameter to thetraceRoute()
methods options - The
_expandConstantObject()
function was declaring variables with global scope
Version 1.2.1 - 14/07/2017
- Document the
Socket.getSocket()
method
Roadmap
Suggestions and requirements should be sent to stephen.vickers.sv@gmail.com.
License
Copyright (c) 2013 Stephen Vickers
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Author
Stephen Vickers stephen.vickers.sv@gmail.com