DTCB(8) Domain/OS BSD DTCB(8)
NAME
dtcb - dump contents of tcp control blocks
SYNOPSIS
/etc/dtcb [-f] [[-t]
[<tcb addr>|-a ] |-u
[<ucb_addr> | -a ]]
DESCRIPTION
The command dtcb dumps the contents of the tcp control blocks associated
with a particular tcp connection. The address of the tcb to be dumped
may be obtained using the netstat program. Two control blocks are
dumped: the ucb (user control block) which contains the send and receive
queues and user-related flags, and the tcb (tcp control block) which
contains the connection sequence numbers, state, flags, and out-of-
sequence queues.
OPTIONS
-f Force output if tcpd not running.
-t <tcb_addr> Hexadecimal address of a tcb or, if not supplied, all
tcbs.
-u <ucb_addr> Hexadecimal address of a ucb or, if not supplied, all
ucbs.
-a All (both tcb's and ucb's for each socket).
EXAMPLES
The dump of a tcp control block for a listening ftp connection might look
like this:
$ /etc/dtcb -t 1A9A50
ucb at 0x1A99C4:
local 0.0.0.0 lport 21
host 0.0.0.0 fport 0
uc_snd 8192 uc_ssize 0 uc_rcv 8192 uc_rsize 0
uc_shead 0 uc_stail 0 uc_rhead 0 uc_rtail 0
xflag:
UREUSEADDR UCANACCEPT
iostate:
status:
UCLOSED
flags:
UTCP
oobmark 0 oobcnt 0
TCB at 0x1A9A50:
lport 0x0 fport 0x0
t_state LISTEN
irs 00000000 rcv_urp 00000000 rcv_urg 00000000 rcv_nxt 00000000
rcv_end 00000000
iss 1E3202D4 seq_fin 1E3202D4 snd_end 1E3202D4
snd_urp 00000000 snd_lst 00000000
snd_nxt 1E3202D4 snd_una 1E3202D4 snd_wl 00000000
snd_hi 1E3202D4
rex_val 00000000 rtl_val 00000000 xmt_val 00000000
flags:
snd_wnd 0 maxseg 0 xmtime 2 rxtct 0
timers:
INIT 0 REXMT 0 REXMTTL 0 PERSIST 0 FINACK 0
t_rcv_next 1A9A50 t_rcv_prev 1A9A50