Re: problem with maddr Via parameter

Thanks for the careful analysis. I will look into this problem ( seems
like it ought to be easy to fix) and commit a fix soon.

Ranga


On 9/7/06, Barton, Jim <[email protected]> wrote:
> I came across an apparent bug in the nist-sip stack dealing with the
> maddr Via parameter. I encountered a exception when doing a
> ServerTransaction.sendResponse() on a received response. The stack trace
> (sorry -- didn't save) showed that the exception was caused by cast
> problem in Via.getMaddr().  I verified that that request did indeed
> contain a maddr Via parameter; although the maddr appeared to me to be a
> valid IP address.
>
> After looking through gov/nist/javax/sip/header/Via.java I discovered
> that that the Via class is somewhat schizophrenic about the type of
> object stored within the parameters collection for the maddr. There is
> method Via.getMaddr() that assumes the maddr in the parameters
> collection is a Host object. It directly casts the object to Host with
> no further checking. This was the direct cause of the exception. There
> is also another method Via.getmaddr() that assumes that the maddr is
> stored as a String within parameters.
>
> With some debugging I verified that the maddr is actually stored by the
> parser as a String, which should cause any later call of Via.getMaddr()
> to throw a cast exception. (setMaddr() will actually create and store an
> maddr as a host -- but the parser does not call this method).
>
> I am able to readily reproduce this problem in the 'simplecallsetup'
> example by simply adding:
>
> viaHeader.setMAddr("224.1.1.1");
>
> following the creation of the ViaHeader for the INVITE.  No changes are
> needed to the 'shootme' application. The shootist has no problem sending
> that INVITE. The shootme has no problem initially processing the INVITE;
> but later gets the bad cast exception when doing a sendResponse() on
> that INVITE.
>
> Jim Barton
>
>
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>


-- 
M. Ranganathan
"There are two ways to write error-free programs; only the third one
works." --  Alan Perlis