Hi, i'm fairly new to newlisp so I thought i''d make a script to validate if a list of anonymous proxy servers in a file are connectable (seems easy enough), but my script seems to stall on the ones that aren't. Here's my code:
(define (check-list file)
(set 'in-file (open file "read"))
(while
(read-line in-file)
(check-state (current-line))
)
(close in-file)
)
(define (check-state server)
(if
(= (net-connect server 8080) nil)
(println (current-line) " is NOT online")
(println (current-line) " is online")
)
)
(check-list "servers.txt")
(exit)
Is there some way to set like a timeout limit on the net-connect so it doesn't hang for ever on the ones that aren't connectable?
i.e. So it can scan a list of ips and quickly tell which are useable.
Hi,
This question has been asked before:
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http://www.alh.net/newlisp/phpbb/viewtopic.php?t=685
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Maybe it's better to perform a 'ping' first, to check if the proxyserver is online. If the proxyserver is out of your network segment and not routed then even the ping will not return.
Peter
How about calling "nmap" with list of hosts/ports and parsing it's output.
Yes, nmap isn't part of newLisp, but instead it designed to scan ports ;-)
The code will looks like "Get a list of local IPs" in "code snippets" page
The ones that arn't connectable will directly return 'nil and wont
hang the session. Those who can will return a handle, but a handle does
not say its accessable..!
this is quick enough.. not too fast but it works..without hangs..
http://www.nodep.nl/downloads/newlisp/portscan.lsp
Try to send someting or read someting for the handle with a (net-select..)
Norman.
well, first off, thanks for the replys. But I still haven't quite got the solution i'm looking for working. From your replys i'm assuming my best bet is to use threads for each connection (so I can continue to check the rest without waiting for timeouts)
or use net-select. But I can't seem to get net-select to work the way it says in the manual.
This is my little script updated from the last version, trying to implement the net-select function.
(define (check-list file)
(set 'in-file (open file "read"))
(while
(read-line in-file)
(check-state (current-line))
)
(close in-file)
)
(define (check-state server)
(if (= (net-lookup server) nil)
(println (current-line) " does not resolve.")
(begin
(set 'sock (net-connect server 8080))
(if (= (net-select sock "write" 1000) nil)
(begin
(println (current-line) " is not connectable on port 8080.")
(net-close sock))
(begin
(println (current-line) " connection made.")
(net-close sock))
)
)
)
)
(if (= (main-args 2) nil)
(begin
(println "Please supply a proxy list as a argument.")
(exit)
)
)
(check-list (main-args 2))
(exit)
from reading the manaul net-select looks like it should return either true or nil after the 1000 mili-seconds. Am I mistaken or am I using net-select the wrong way?
what is the advantage of this script?
net-connect is bloking either, so, if port is filtered out by "drop" policy (as usual :) it will not return anything until long timeout.
So, if U still want to use net-connect, threads will be a good choice.
btw, nil in newLisp is equivalent of "false", and
(if (= (net-lookup server) nil) ...
is equivalent to
(if (net-lookup server) ...
Quote from: "Dmi"
btw, nil in newLisp is equivalent of "false", and
(if (= (net-lookup server) nil) ...
is equivalent to
(if (net-lookup server) ...
(if (net-lookip server))
isn't equivalent to
(if (= (net-lookup server) nil).
perhaps you mean !=
And newdep suggested using net-select, which seems like the easier route. That's why I decided to try and use it.
... about nil: of course !=
about select: net-select operates on descriptor, given from net-connect (or net-listen, but it's not our case).
It's in your code:
(if (= (net-select sock "write" 1000) nil)
But net-connect blocks on filtered ports (I just have checked for that).
So, net-select runs always _after_ net-connect, and after it's timeout.
ohhhhh. hehe Dmi. I understand now. Thanks for clearing that up. :)
A net-select on a net-connect is always true for "r" "w" "a" on a opened socket! That wont help in this case..
Norman.