10.2;dtcb (dump tcp control blocks), revision 2.0, 89/03/31
dtcb (dump tcp control blocks) -dump contents of tcp control blocks
usage: /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. 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.
Obtain the address of the tcb to be dumped by using the netstat -A
command. The tcb is listed under the column headed with PCB. Obtain the
ucb for a socket by executing the dtcb command on the socket's tcb.
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 e9064d4
############################################
---------- TCB at e9064d4 UCB at e90786c:
lport 0 fport 0
t_state ESTAB
irs 24A3A08B rcv_urp 24A3A08B rcv_urg 24A3A08C rcv_nxt 24A3A0A6
rcv_end 00000000
iss 251A4222 seq_fin 251A4222 snd_end 251A42B8 snd_urp 00000000
snd_lst 251A42B8
snd_nxt 251A42B8 snd_una 251A42B8 snd_wl 24A3A0A6 snd_hi 251A42B8
rex_val 251A42B8 rtl_val 251A42B8 xmt_val 251A429B
tcb flags:
SYN_ACKED SYN_RCVD
snd_wnd 9116 maxseg 1420 xmtime 3 rxtct 0
timers:
INIT 0 REXMT 0 REXMTTL 0 PERSIST 0 FINACK 0
t_rcv_next E9064D4 t_rcv_prev E9064D4
---------- UCB at e90786c TCB at e9064d4:
local 192.9.99.4.21 host 192.9.99.3.1026
uc_snd 9116 uc_ssize 0 uc_rcv 9116 uc_rsize 0
uc_shead 0 uc_stail 0 uc_rhead 0 uc_rtail 0
uc_srcif itr0 uc_refcnt 0
uc_qhead 0 uc_gway 0
uc_q0 0
uc_q 0
uc_xflag (0001): ULINKED
uc_iostate (2000): IS_CONNECTED
uc_status (0000):
uc_flags (0002): UTCP
uc_options (0104): SO_REUSEADDR SO_OOBINLINE
uc_error 0 uc_xstat 0 uc_backlog 0
oobmark 0 oobcnt 0