talkd

[Mateus Cordeiro Inssa]

David S. Miller writes:
 >    From: Mateus Cordeiro Inssa <mateus en ifnet.com.br>
 >    Date:   Sun, 30 Jan 2000 00:40:40 -0200 (BRDT)
 > 
 >      I saw this messages too and what I discovered was:
 > 
 >    1) Create an udp socket and bind it to a port and INADDR_ANY
 >    2) Send a mensage to this socket from localhost
 >    3) The first recvfrom returns the sockaddr with address (IP) equal 0
 >    (not 127.0.0.1 or ethernet address) and replying to this request with
 >    this sockaddr causes that printk .
 >    4) Next recvfrom returns sockaddr right.
 > 
 > In #3 an error was returned, and when an error occurs the contents
 > of the sockaddr you pass in is undefined on returned.  This should
 > be the only way you could see the behavior you describe.

  I'm not sure, but it seemed full of zeroes.

 > The IP address being zero supports this fact.
 > 
 > So the code in question should have checked the error return
 > from the recvmsg call at #3.  I bet this application puts
 > the socket in non-blocking mode too.

  Of course the application check for errors, but the error always
occur in the first recvfrom. The application doesn't change any
socket property, so I assume it is on blocking mode.
  The sequence is: socket, bind, select,recvfrom. No one uses any
extra param.

 > 
 > Later,
 > David S. Miller
 > davem en redhat.com

Mateus Cordeiro Inssa
---------------------
Linux User: 76186  Kernel: 2.3.40
ICQ (Licq): 15243895
---------------------
mateus en ifnet.com.br
mateus en cwb.fnn.net

Mon Jan 31 09:13:54 BRDT 2000

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