/**
* The Missing (TCP_KEEPINTVL and TCP_KEEPCNT) SO_KEEPALIVE socket option setters and getters for Node using
* ffi-napi module.
*
* Note: For methods provided by this module to work you must enable SO_KEEPALIVE and set the TCP_KEEPIDLE options for
* socket using Net.Socket-s built in method socket.setKeepAlive([enable][, initialDelay]) !
*
* @author George Kotchlamazashvili <georgedot@gmail.com>
*
* @example <caption>CommonJS</caption>
* require('net-keepalive')
*
* @example <caption>ES Modules</caption>
* import * as NetKeepalive from 'net-keepalive'
*
* @module net-keepalive
* @since v0.1.0
*/
'use strict'
const Assert = require('assert'),
Net = require('net'),
OS = require('os'),
Constants = require('./constants'),
Ref = require('ref-napi'),
FFIBindings = require('./ffi-bindings')
const _isSocket = (socket) => socket instanceof Net.Socket
const _getSocketFD = (socket) => {
const fd = socket._handle != null ? socket._handle.fd : undefined
if (OS.platform() !== 'win32') {
Assert(fd && fd !== -1, 'Unable to get socket fd')
}
return fd
}
/**
* Sets the TCP_KEEPINTVL value for specified socket.
*
* Note: The msec will be rounded towards the closest integer
*
* @since v0.1.0
* @param {Net.Socket} socket to set the value for
* @param {number} msecs to wait in-between probes
*
* @returns {boolean} <code>true</code> on success
*
* @example <caption>Set interval in-between probes to 1 second (<code>1000</code> milliseconds) for socket <code>s</code></caption>
* NetKeepAlive.setKeepAliveInterval(s, 1000)
*
* @throws {AssertionError} setKeepAliveInterval requires two arguments
* @throws {AssertionError} setKeepAliveInterval expects an instance of socket as its first argument
* @throws {AssertionError} setKeepAliveInterval requires msec to be a Number
* @throws {ErrnoException|Error} Unexpected error
*/
module.exports.setKeepAliveInterval = function setKeepAliveInterval(
socket,
msecs
) {
Assert.strictEqual(
arguments.length,
2,
'setKeepAliveInterval requires two arguments'
)
Assert(
_isSocket(socket),
'setKeepAliveInterval expects an instance of socket as its first argument'
)
Assert.strictEqual(
msecs != null ? msecs.constructor : void 0,
Number,
'setKeepAliveInterval requires msec to be a Number'
)
const fd = _getSocketFD(socket),
seconds = ~~(msecs / 1000),
intvlVal = Ref.alloc('int', seconds),
intvlValLn = intvlVal.type.size
return FFIBindings.setsockopt(
fd,
Constants.SOL_TCP,
Constants.TCP_KEEPINTVL,
intvlVal,
intvlValLn
)
}
/**
* Returns the TCP_KEEPINTVL value for specified socket.
*
* @since v1.1.0
* @param {Net.Socket} socket to check the value for
*
* @returns {number} interval (ms) in-between probes
*
* @example <caption>Get the current interval in-between probes for socket <code>s</code></caption>
* NetKeepAlive.getKeepAliveInterval(s) // returns 1000 based on setter example
*
* @throws {AssertionError} getKeepAliveInterval requires one arguments
* @throws {AssertionError} getKeepAliveInterval expects an instance of socket as its first argument
* @throws {ErrnoException|Error} Unexpected error
*/
module.exports.getKeepAliveInterval = function getKeepAliveInterval(socket) {
Assert.strictEqual(
arguments.length,
1,
'getKeepAliveInterval requires one arguments'
)
Assert(
_isSocket(socket),
'getKeepAliveInterval expects an instance of socket as its first argument'
)
const fd = _getSocketFD(socket),
intvlVal = Ref.alloc(Ref.types.uint32),
intvlValLn = Ref.alloc(Ref.types.uint32, intvlVal.type.size)
FFIBindings.getsockopt(
fd,
Constants.SOL_TCP,
Constants.TCP_KEEPINTVL,
intvlVal,
intvlValLn
)
return intvlVal.deref() * 1000
}
/**
* Sets the TCP_KEEPCNT value for specified socket.
*
* @since v0.1.0
* @param {Net.Socket} socket to set the value for
* @param {number} cnt number of probes to send
*
* @returns {boolean} <code>true</code> on success
*
*
* @example <caption>Set number of probes to send to 1 for socket <code>s</code></caption>
* NetKeepAlive.setKeepAliveProbes(s, 1)
*
* @throws {AssertionError} setKeepAliveProbes requires two arguments
* @throws {AssertionError} setKeepAliveProbes expects an instance of socket as its first argument
* @throws {AssertionError} setKeepAliveProbes requires cnt to be a Number
* @throws {ErrnoException|Error} Unexpected error
*/
module.exports.setKeepAliveProbes = function setKeepAliveProbes(socket, cnt) {
Assert.strictEqual(
arguments.length,
2,
'setKeepAliveProbes requires two arguments'
)
Assert(
_isSocket(socket),
'setKeepAliveProbes expects an instance of socket as its first argument'
)
Assert.strictEqual(
cnt != null ? cnt.constructor : void 0,
Number,
'setKeepAliveProbes requires cnt to be a Number'
)
const fd = _getSocketFD(socket),
count = ~~cnt,
cntVal = Ref.alloc('int', count),
cntValLn = cntVal.type.size
return FFIBindings.setsockopt(
fd,
Constants.SOL_TCP,
Constants.TCP_KEEPCNT,
cntVal,
cntValLn
)
}
/**
* Returns the TCP_KEEPCNT value for specified socket.
*
* @since v1.1.0
* @param {Net.Socket} socket to check the value for
*
* @returns {number} number of probes to send
*
* @example <caption>Get the current number of probes to send for socket <code>s</code></caption>
* NetKeepAlive.getKeepAliveProbes(s) // returns 1 based on setter example
*
* @throws {AssertionError} getKeepAliveProbes requires one arguments
* @throws {AssertionError} getKeepAliveProbes expects an instance of socket as its first argument
* @throws {ErrnoException|Error} Unexpected error
*/
module.exports.getKeepAliveProbes = function getKeepAliveProbes(socket) {
Assert.strictEqual(
arguments.length,
1,
'getKeepAliveProbes requires one arguments'
)
Assert(
_isSocket(socket),
'getKeepAliveProbes expects an instance of socket as its first argument'
)
const fd = _getSocketFD(socket),
cntVal = Ref.alloc(Ref.types.int),
cntValLn = Ref.alloc(Ref.types.int, cntVal.type.size)
FFIBindings.getsockopt(
fd,
Constants.SOL_TCP,
Constants.TCP_KEEPCNT,
cntVal,
cntValLn
)
return cntVal.deref()
}
/**
* Sets the TCP_USER_TIMEOUT (TCP_RXT_CONNDROPTIME on `darwin`) value for specified socket.
*
* Notes:
* * This method is only supported on `linux` and `darwin`, will throw on `freebsd`.
* * The msec will be rounded towards the closest integer.
* * When used with the TCP keepalive options, will override them.
*
* @see {@link https://man7.org/linux/man-pages/man7/tcp.7.html|tcp(7):TCP_USER_TIMEOUT }
*
* @since v1.4.0
* @param {Net.Socket} socket to set the value for
* @param {number} msecs to wait for unacknowledged data before closing the connection
*
* @returns {boolean} <code>true</code> on success
*
* @example <caption>Set user timeout to 30 seconds (<code>30000</code> milliseconds) for socket <code>s</code></caption>
* NetKeepAlive.setUserTimeout(s, 30000)
*
* @throws {AssertionError} setUserTimeout requires two arguments
* @throws {AssertionError} setUserTimeout called on unsupported platform
* @throws {AssertionError} setUserTimeout expects an instance of socket as its first argument
* @throws {AssertionError} setUserTimeout requires msec to be a Number
* @throws {ErrnoException|Error} Unexpected error
*/
module.exports.setUserTimeout = function setUserTimeout(socket, msecs) {
Assert.strictEqual(
arguments.length,
2,
'setUserTimeout requires two arguments'
)
Assert(
Constants.TCP_USER_TIMEOUT != null,
'setUserTimeout called on unsupported platform'
)
Assert(
_isSocket(socket),
'setUserTimeout expects an instance of socket as its first argument'
)
Assert.strictEqual(
msecs != null ? msecs.constructor : void 0,
Number,
'setUserTimeout requires msec to be a Number'
)
const fd = _getSocketFD(socket),
msecInt = ~~msecs,
msecVal = Ref.alloc('int', msecInt),
msecValLn = msecVal.type.size
return FFIBindings.setsockopt(
fd,
Constants.SOL_TCP,
Constants.TCP_USER_TIMEOUT,
msecVal,
msecValLn
)
}
/**
* Returns the TCP_USER_TIMEOUT value for specified socket.
*
* Note: This method is only supported on `linux`, will throw on `darwin` and `freebsd`.
*
* @since v1.4.0
* @param {Net.Socket} socket to check the value for
*
* @returns {number} msecs to wait for unacknowledged data before closing the connection
*
* @example <caption>Get the current user timeout for socket <code>s</code></caption>
* NetKeepAlive.getUserTimeout(s) // returns 30000 based on setter example
*
* @throws {AssertionError} getUserTimeout requires one arguments
* @throws {AssertionError} getUserTimeout called on unsupported platform
* @throws {AssertionError} getUserTimeout expects an instance of socket as its first argument
* @throws {ErrnoException|Error} Unexpected error
*/
module.exports.getUserTimeout = function getUserTimeout(socket) {
Assert.strictEqual(
arguments.length,
1,
'getUserTimeout requires one arguments'
)
Assert(
Constants.TCP_USER_TIMEOUT != null,
'getUserTimeout called on unsupported platform'
)
Assert(
_isSocket(socket),
'getUserTimeout expects an instance of socket as its first argument'
)
const fd = _getSocketFD(socket),
msecVal = Ref.alloc(Ref.types.uint32),
msecValLn = Ref.alloc(Ref.types.uint32, msecVal.type.size)
FFIBindings.getsockopt(
fd,
Constants.SOL_TCP,
Constants.TCP_USER_TIMEOUT,
msecVal,
msecValLn
)
return msecVal.deref()
}
Source