Re: binding UDP port 0 with SO_REUSEADDR

On Thu, 2012-08-02 at 18:33 +0200, Tobias S. Josefowitz wrote:

Hi again,

I need to say, after looking at "my" socket(7),

       SO_REUSEADDR
              Indicates  that  the rules used in validating addresses supplied
              in a bind(2) call should allow reuse of  local  addresses.   For
              AF_INET  sockets  this means that a socket may bind, except when
              there is an active listening socket bound to the address.   When
              the listening socket is bound to INADDR_ANY with a specific port
              then it is not possible to bind  to  this  port  for  any  local
              address.  Argument is an integer boolean flag.

I think the surprise-factor of the bind-0-behaviour even increased for
me. Is there a specific reason for handing out used ports when binding
port 0 with REUSEADDR?

There is no concept of listening sockets for UDP.

This documentation applies for TCP, and makes no sense for UDP.

There is no value using 'port 0' and REUSEADDR on UDP, really.