The Q bit in X.25 doesn't mean "this is QLLC traffic", it's just a "this
packet is special" indication. Have the X.25 dissector pass as the
"private_data" pointer a pointer to a gboolean indicating whether the Q
bit was set or not. Replace the "decode non-Q-bit traffic as SNA"
option with a "decode traffic as QLLC/SNA if we didn't see the Call
Request packet and thus don't know what it is" option, which hands
traffic to the QLLC dissector for that traffic. Have the QLLC dissector
hand traffic to the SNA dissector if the Q bit isn't set.
Arrange that we determine whether the Q bit is set regardless of whether
we're building the protocol tree or not.
If we don't just dissect traffic as QLLC/SNA if we didn't see the Call
Request packet, check not only for 0x45 (as an indication that it's
probably IP), check also for NLPID_ISO8473_CLNP and treat that as an
indication that it's probably OSI CLNP.
svn path=/trunk/; revision=6854
Guy Harris