In tcp_usr_shutdown() and tcp_usr_send(), I missed converting NULL checks for the tcpcb, previously used to detect complete disconnection, with INP_DROPPED checks.  Correct that, preventing shutdown() from improperly generating a TCP segment with destination IP and port of 0.0.0.0:0.
In tcp_usr_shutdown() and tcp_usr_send(), I missed converting NULL
checks for the tcpcb, previously used to detect complete disconnection,
with INP_DROPPED checks.  Correct that, preventing shutdown() from
improperly generating a TCP segment with destination IP and port of
0.0.0.0:0.

PR:		kern/132050
Reported by:	david gueluy <david.gueluy at netasq.com>
MFC after:	3 weeks

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase