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eping is a Scheme implementation of the ICMP ping utility. Although it can be used like an average OS ping utility, eping is intended to be used programmatically (e.g. for gathering statistics, monitoring). It uses raw sockets thus a privileged account must be used.
[procedure] (eping HOST #!key (mode 'probe) (count #f) (timeout 1000) (interval 1000) (ttl 64) (tos 0) (dont-fragment #f) (src-addr #f) (id #f) (seq-start 0) (size 56) (pattern "") (recv-min #f) (lost-max #f) (cons-recv-min #f) (cons-lost-max #f) (msg1 "%i is alive%n") (msg2 "") (dotcols 0) (quiet #t))
HOST can be either an IPv4 address or an hostname: '192.168.1.1 , "192.168.1.1" , 'example.com, "example.com" are all valid hosts.
eping supports four modes of operation: probe (default), stats, dot and mtu.
In this mode eping returns true or false if it considers an host alive or unreachable respectively. The default behavior is to consider an host alive as soon as an echo reply is received. If no reply is received in count attempts, the host is considered unreachable. If not specified, count is 5 by default. Probe mode is the default one so it can be omitted as parameter.
(eping "call-cc.org") ===> #t
The aliveness criteria can be changed through the four parameters recv-min, lost-max, cons-recv-min, cons-lost-max (see "Parameters" section). As soon as one of this conditions is met eping returns the associated boolean value. If no condition is met in count attempts #f is returned.
In non-quiet 'submode' a message is displayed as well.
(eping "call-cc.org" quiet: #f) 22.214.171.124 is alive
The output message can be customized through the msg1 and msg2 parameters.
In stats mode eping returns a vector of statistics #(sent lost rtt-min rtt-avg rtt-max rtt-std). The rtt values are expressed in ms.
(eping "call-cc.org" mode: 'stats) ==> #(5 0 133 134.2 136 0.92)
In non-quiet 'submode' the output resembles a standard ping utility:
(eping "call-cc.org" mode: 'stats quiet: #f) 64 bytes from 126.96.36.199: icmp_seq=0 ttl=52 time=139ms 64 bytes from 188.8.131.52: icmp_seq=1 ttl=52 time=227ms 64 bytes from 184.108.40.206: icmp_seq=2 ttl=52 time=135ms 64 bytes from 220.127.116.11: icmp_seq=3 ttl=52 time=170ms 64 bytes from 18.104.22.168: icmp_seq=4 ttl=52 time=256ms --- call-cc.org ping statistics --- 5 packets transmitted, 5 packets received, 0% packet loss round-trip min/avg/max/stddev = 135.0/185.4/256.0/48.26 ms
Ctrl-\ (SIGQUIT) can be used to print partial statistics without stopping the ping (POSIX platforms only). Ctrl-C can be used to stop and collect the statistics at any moment.
By default 5 packets are sent. The count option can be used to change this value (0 meaning continuos operation).
In this mode eping returns a single character for each echo request:
- [.] Echo reply received
- [!] No response
- [N] Network unreachable
- [H] Host unreachable
- [P] Protocol unreachable
- [F] Packet too big and DF bit set
- [A] Administratively filtered
- [T] Time to live exceeded
- [O] Network/Host unreachable for TOS
- [U] Unreachable (generic error)
(eping "call-cc.org" mode: 'dot quiet: #f timeout: 134 count: 20) ..!...!....!.!!!....
The dotcols parameter can be used to set the number of chars to be printed before a newline. The default behavior (0) inserts a newline only after the last echo request.
(eping "call-cc.org mode": 'dot quiet: #f timeout: 134 count: 20 dotcols: 5) !...! ....! ...!. !....
In quiet 'submode' a string built from the generated characters is returned.
(eping "call-cc.org" mode: 'dot count: 3) "..."
In mtu mode eping attempts to compute the MTU in the path. To speed up the process it is advisable to lower the default 1000ms echo requests interval time (interval option).
(eping "call-cc.org" mode: 'mtu interval: 250) ===> 1492
Lossy links may slow down or even prevent the convergence. The count option can be used to increase the number of attempts (default is 64). If mtu can't be computed #f is returned.
- count The number of echo requests to be sent. The default is 5 for modes other than mtu and 64 for mtu mode. If set to 0 echo requests are sent until a probe condition is met (probe mode), mtu is computed (mtu mode) or SIGINT (Ctrl-C) is received (all modes).
- timeout The amount of time in ms to let pass before considering an host unreachable (default is 1000ms).
- interval The interval in ms between echo requests (default is 1000ms). This value can't be set lower than timeout (this rule is enforced lowering *timeout* in case).
- ttl / tos Respectively the Time To Live and TOS in the IP header.
- dont-fragment Sets the Don't Fragment (DF) flag in the IP header.
- src-addr Binds the ICMP socket to a specific IP address.
- size The ICMP payload size.
- pattern A string used to fill the payload (repeated if necessary).
- id The Identifier field (0-65535). By default it is generated randomly for every invocation of the eping function.
- seq-start The initial sequence of the echo requests (0 by default).
- recv-min Minimum number of received replies before considering an host alive.
- lost-max Maximum number of missed replies before considering an host unreachable.
- cons-recv-min Minimum number of consecutive received replies before considering an host alive.
- cons-lost-max Maximum number of consecutive missed replies before considering an host unreachable.
- msg1 The message displayed when an host is considered alive. The default message is "%i is alive%n" where %i is interpreted as the IP address of the host. Similarly %h is interpreted as the hostname while %n inserts a newline.
- msg2 The message displayed when an host is considered unreachable. By default it is an empty string.
- dotcols In dot mode the number of displayed chars before a newline is inserted. By default (0) a newline is inserted only after the last displayed char.
- quiet By default eping doesn't display anything unless this option is set to #f.
About this egg
- Initial release
Michele La Monaca
Copyright (c) 2013 Michele La Monaca (mikele~lamonaca.net) All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1) Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2) Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3) Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.