Hello Guy, I am using asn1 BER encoding at the sending side. And It is hard to figure it out what exactly is the length byte. I have read the hexdump for some different messages, they are varying.
I might be trying your suggestion when I get time. But thanks anyway. Zongjun On 9/27/07, Guy Harris <[EMAIL PROTECTED]> wrote: > > > On Sep 27, 2007, at 4:30 PM, Zongjun wrote: > > > I could have 30 different kinds of messages and I just can't know > > the fix length. However, using tcp_dissect_pdus you have to give the > > fix length. > > No. > > Using tcp_dissect_pdus() you have to give: > > 1) a fixed minimum length, which: > > includes all the data necessary to determine the message > length; > > is no longer than the shortest message length; > > 2) a routine that, given the minimum length worth of data, > determines > the message length. > > What determines the message length in your protocol? > > Is there a message length field in all messages, at the same offset > from the beginning of the message in all messages? If so, then the > minimum length is the length of the message length field plus the > length of the data preceding the message length field. > > If not, is there a message type field in all messages, at the same > offset from the beginning of the message in all messages, and can the > length of the message be determined from the value of the message type > field? If so, then the minimum length is the length of the message > type field plus the length of the data preceding the message length > field. > > If not, what else is used to determine the length of the message? > _______________________________________________ > Wireshark-dev mailing list > [email protected] > http://www.wireshark.org/mailman/listinfo/wireshark-dev > -- Thanks, Zongjun
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