Jacek's Status Report #8 of 13

[Jacek Wielemborek <d33tah () gmail com>]

Hello,

This is my report for week 8 of "Nsock-based port scanning"
Google Summer of Code project.

Accomplishments:

* Reworked send_next_probes, implemented per-host congestion control,
added more debug output and fixed another bug in the congestion control
subsystem,

* Experimented a lot with the congestion control system:
 -> Analyzed Nmap's odd behavior while -p- scanning scanme.nmap.org and
    8.8.8.8,
 -> Created a script that tests how my code behaves compared to the SVN
    trunk on networks with packet loss. The script uses "scanning" and
    "scanned" VMs - "scanned" just responds with SYN+ACK to every SYN,
    while "scanning" VM uses Linux "netem" functionality to simulate
    packet loss. Then, both timing and detected open ports count is
    compared,

* Modified Nsock to enable connection lingering and --ttl support,

* Added -e support,

* Made my code more object-oriented, hopefully making it easier to build
a port-scanning framework in the future,

* Added early timeouts support. Before, my code detected drops only when
connect() finally led to ETIMEDOUT. After this change, Nmap's RTT
calculation code is used and we disconnect and signal a drop when a
timeout should happen anyway. This change was not tested yet,

* Had a meeting with my mentor, in which he explained me how timeouts
work in Nmap and how this relates to its congestion control subsystem.
We also talked this project's future - we both agreed that it will be
impossible to complete this project by the end of Google Summer of Code.
We discussed various options for plans for the remaining few weeks; I'll
probably write more about this later.

Priorities:

* Investigate why my code is slower and sometimes detects less ports
compared to the SVN trunk when --max-send-delay is set to 0,

* Keep working on the regression testing program.

Yours,
Jacek Wielemborek

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