Memory usage of nmap

["Sina Bahram" <sbahram () nc rr com>]

Hi all,

I have noticed something while running nmap 3.94 alpha 3 on xp with sp2.

If you do a ping scan of a number of hosts ... Let us say

a.b.c.*

Nmap will cruise along at some memory usage ... Let's say x, but then as
soon as it finds some hosts, this memory usage increases by 10% or so ...
Then it never goes back down

So for example, we could scan

a.b.*.*

Let's say though that we already know that a.b.1.1,100-104 are the only
hosts up ... It'll be scanning along at this memory usage x ... Ten suddenly
bam! Up to 30% memory usage increase, as compared to 10% in the 255 IP
example ...

Then let's try a really huge range ...

a.*.*.*

This is interesting ... So what happens now is that you'll be going right
along at some memory usage X and then suddenly a sharp drop ... Then a surge
back up, but to less than what you were at before; however, steadily (slow
but surely) increasing in 4 byte chunks ...

I'm not saying there's a memory leak, ... It does look like a malloc/new
that never gets free/deleted, but I also can think of several other things
such as the use of some vector based class that could cause this?

Any ideas, and also have other people noticed this behavior?

By the way, the reason I bring it up is because I jumped from around 9mb of
mem usage to around 13mb or so memory usage ...

Take care,
Sina



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