[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#783160: ax25-tools: The most part of IP-over-AX25 outbound packets (e.g. ICMP requests) are sent duplicated



Package: ax25-tools

Version: 0.0.10-rc2+cvs20120204-3

Justification: renders package unusable

Severity: grave

 

Dear Maintainer,

 

   * What led up to the situation?

 

During a simple IP-over-AX25 activity (1200 baud) I found  high number of TCP errors (duplicated, out of sequence…). The detailed analysis shows that the most part of packet are sent twice.

In the attachment you can find a “sniffing” pcap file showing a simple case of an ICMP request.

The problem affects Wheezie versions both on 32 and 64bits machines and also over Raspbian.

In the attachment you will see two sniffing files related to the same simple ICMP exchange (one hop) : 7 pings of 100 bytes (less then the MTU, that is 256) spaced of 10 sec (-i 10 -s 100).

What I found strange it’s that each ping seems to be duplicated in two requests (same checksum both at IP and TCP level) : for example (see “ax0”) frame 1 and frame 2 , frames 5 and 6, frames 9 and 20 and so on.

The effects are :

 

Ø  That the ICMP seems unable to match request and answer

Ø  That a multiple useless transmissions are generated (there are a huge number of duplicated and out-of-order TCP packets in a real transmission, FTP or telnet…)

Ø  I’m afraid also that the stack incorrectly calculated window and smoothed average bit rate (but not sure)

 

 

   * What exactly did you do (or not do) that was effective (or

     ineffective)?

 

I’m working with the default settings.

Using alternative ax25 stack (Lin-BPQ) on the same machines show a normal situation (ICMP request not duplicated)

 

 

-- System Information:

Debian Release: 7.8

  APT prefers stable-updates

  APT policy: (500, 'stable-updates'), (500, 'stable')

Architecture: i386 (i686) (but also on 64bits or Raspbian machine)

 

Kernel: Linux 3.2.0-4-486

Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)

Shell: /bin/sh linked to /bin/dash

 

Versions of packages ax25-tools depends on:

ii  libax25  0.0.12-rc2+cvs20120204-2

ii  libc6    2.13-38+deb7u8

ii  zlib1g   1:1.2.7.dfsg-13

 

ax25-tools recommends no packages.

 

Versions of packages ax25-tools suggests:

pn  ax25-apps  <none>

pn  talkd      <none>

 

-- no debconf information

 

Regards, 73

Ugo


Reply to: