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psthru.plm
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PSTHRU.PLM - Documentation for PSTHRU
Page 2
Copyright (C) 1982
Digital Equipment Corporation, Maynard, Massachusetts,
U.S.A.
This software is furnished under a license and may be used
and copied only in accordance with the terms of such license
and with the inclusion of the above copyright notice. This
software or any other copies thereof may not be provided or
otherwise made available to any other person. No title to
and ownership of the software is hereby transferred.
The information in this software is subject to change
without notice and should not be construed as a commitment
by Digital Equipment Corporation.
Digital assumes no responsibility for the use or reliability
of its software on equipment which is not supplied by
Digital.
PSTHRU.PLM Page 3
General information
I. General information
PSTHRU is a program which allows connects to be made
from any accessable DECnet-10 or ANF-10 node through the
host node to any other DECnet-10 or ANF-10 node which is
visible to the host node. The links need not be homogenous.
PSTHRU runs completely asynchronously and handles all
incoming connects to the PSTHRU object (object 123 decimal
for DECnet-10 or 173 octal for ANF-10). Only one job need
be run per installation unless link quotas are such that one
job cannot handle the required number of links. One channel
(of the appropriate type) is required for each side of a
link (total of two channels per link).
PSTHRU should be started up via SYSJOB.INI. If it is
not logged in, then it will log in to [2,5]. It is
recommended that it be run under [1,2], although no
privileges are required unless the log file (see below) is
to be written to an area to which only [1,2] has file
access.
If the PATHological name PSTLOG exits and logging
support is enabled, PSTHRU will log all connections,
rejections, failures, and disconnects in the specified file.
If the specification is undefined and logging is enabled,
then one message will be sent to ORION stating PSTHRU's
inability to set logging.
PSTHRU is written to run under TOPS-10 7.02 monitors.
DECnet support is required only if the DECnet interface is
desired. The MACSYM universal file is required for the
BEGSTR/ENDSTR macros.
Known restrictions:
1. ANF-10 supports only 32-bit modes (byte mode; I/O
mode 3). This is true both for heterogenous and
homogenous connects. This restriction is to
provide a common "known" mode for communicating
through the PSTHRU task to maintain correct
resolution and byte counts.
2. ANF-10 links take precedence over DECnet links when
ambiguity is present (i.e. the same node name in
both networks and the requested connection object
exists on the ANF node).
3. Error messages are always a la' DECnet style, even
if DECnet support is not build in.
II. Assembly instructions
PSTHRU.PLM Page 4
Assembly instructions
Feature tests:
1. FTDECNET: if on (-1), include DECnet-10 support
code. If off (0) do not. One of FTDECNET or
FTANF10 must be on.
2. FTANF10: if on (-1) include ANF-10 support code.
If off (0), do not. One of FTDECNET or FTANF10
must be on.
3. FTDEBUG: if on (-1) include a few extra
consistency checks.
4. FTLOG: if on (-1) include support for producing
log files.
5. FTDETACH: if on (-1), then DETach from the
terminal on which the program is started. This
feature should be turned off only for debugging
purposes.
The default list of feature tests is to have FTDECNET,
FTANF10, FTDETACH, and FTLOG all turned on and FTDEBUG
turned off.
Required files:
PSTHRU.MAC
UUOSYM.UNV
MACTEN.UNV
MACSYM.UNV
NETPRM.UNV
JOBDAT.UNV
Assembly instructions:
.LOAD PSTHRU
.SSAVE
There are a few additional assembly parameters which
may also be changed:
1. BUFNUM (default=6): This is the number of message
buffers built at initialization time. The list
will be expanded as is necessary, but buffers are
never returned to the free core list (only to the
free buffer list).
2. BUFSIZ (default=100): This is the data size of a
buffer for input. Messages larger than this will
be fragmented. This is the size of the data
portion of the buffer only and does not include any
overhead words (currently there are three
additional words).
PSTHRU.PLM Page 5
Assembly instructions
3. QUEMAX (default=20): This parameter dictates the
maximum number of buffers which may be queued up
for writing on one side of a link. The absolute
maximum number is also governed by the MAXRED
parameter and is equal to QUEMAX+MAXRED. At this
point no data available interrupts will be
acknowledged on the read side of the link until the
write side's queue is empty. Note that this
restriction is held only as long as the link
remains in RN state. This is so that if the read
side of the link is just slow and the write side is
trying to disconnect, it will be able to.
4. MAXRED (default=10): This is the maximum number of
buffers which will be read on a read request if
infinited data were available. See the
documentation on QUEMAX for other effects of this
parameter.
5. QUMLEN (default=132): This is the maximum length
of any error message which will be sent to the
operator.
PSTHRU.PLM Page 6
Edit history
III. Edit history
1. (1) Design and implement original features.
2. (2) Fix core allocation bug for one word
3. (3) Fix bug where a NSP returns no data, but there is
more to be read. This could cause a hang after such.
4. (4) Fix NPDSTR: doing a HLRI instead of a HRLI and
CPYOBJ doing a HRLI T3,(POINT 8,,) instead of HRLI
T3,(POINT 8,,35). Symptom: causes connections to be
made with junk object names (format type 1).
5. (5) Change dump area to XPN:
6. (6) Change default buffer size from 100 to 200 (octal)
7. (7) Update for new DNET. UUO.
8. (10) Make DECnet Send/Read Normal/Interrupt ABORT
stopcodes instead of INFO. Make ABORT stopcodes work
better.
9. (11) Range check the size of fields in access control
information
10. (12) Make sure there's a <NUL> at the end of the string
for the QUEUE. UUO so that the message sent to ORION
doesn't have old garbage in it. Clean up DIE; remove a
HALT that can't be executed and zero out the PPN and
access stuff field of the LOOKUP block (which are the
PPN and reserved fields of the SAVE. block) before each
LOOKUP.
11. (13) Edit 11 wasn't complete - changing SOSLE to SOSL
causes a bit spray because a core block is allocated and
pointed to before we decide the string is terminated.
Change it back to a SOSLE and then check to be sure the
last character is a quote, eating one more and checking
it if it is not.
12. (14) Make NPD object numbers read octal instead of
decimal.
13. (15) Don't assume "last link" just because access
control info is given; this allows users to specify
access control info for the PSTHRU they want to connect
to (it will have meaning for DECnet at least).
14. (16) ANFEOF must clear T2 if it doesn't call ANFRD so we
won't think there are any buffers to deallocate.
PSTHRU.PLM Page 7
Edit history
IV. Architecture philosophies
This section deals with the various implementation
decisions that were made in creating the PSTHRU interface.
As was mentioned earlier, all connections are made in
32-bit mode. This decision was made to provide (also as
mentioned earlier) a standard connect mode which would
maintain proper resolution and byte size. As you might also
guess, it's due to ease of programming due to the DECnet
interface which is byte oriented.
ANF connections take precedence over DECnet
connections: this is in conformance with the behaviour of
SET HOSTES.
Note also that PSTHRU declares itself to the next
succeeding part of the link as whatever it was connected to
with. This is in conformance to the behaviour of PSTHRU
objects on other systems.
Below is a quote from the NFT program, reproduced here
for your edification, which describes the philosophy of the
ANF interface:
As ANF-10 basically doesn't support any of the
"wonderous" errata of DECnet such as user-id, password,
ad nauseum, the TSK. monitor call was invented to give
the user fuller control over the network logical link.
In particular, in conjunction with versions 3 and later
of the DECnet Compatible Port (in the DN8x), the
"network process descriptor" was made available to the
"user" in order to encode all that stuff in such a way
that the DCP can convert it into something the DECnet
side understood. The result is a very arcane NPD
string (for which honesty requires that I not claim any
credit) given to the TSK. in the active and passive
init functions. The form of that NPD string, for the
first time anywhere ever put in writing, is:
<0> ;leading null byte
DST ;"destination" process identifier
<0> ;punctuation byte
SRC ;"source" process identifier
<0> ;punctuation byte
USERID ;user id string
<0> ;punctuation byte
PASSWORD ;password string for user id
<0> ;punctuation byte
ACCOUNT ;account string for user id
<0> ;punctuation byte
OPTDATA ;"optional user data" a la DECnet connect init
<0> ;punctuation byte
DST and SRC both are one of the following forms:
PSTHRU.PLM Page 8
Architecture philosphies
OBJ ;format 0: DECnet object type
OBJ.NAM ;format 1: DECnet object type and task name
; note the "." punctuation character
OBJ is the object type as an ASCII octal number - e.g.,
"21" for DAP. NAM, USERID, PASSWORD, ACCOUNT, and
OPTDATA are all "ASCII" character strings - i.e., 7-bit
bytes (with no nulls).
PSTHRU.PLM Page 9
Architecture philosphies
V. Program messages and stop codes
PSTHRU is built to notify the operator about various
problems which can occur. These are listed below in detail.
In general, most messages are accompanied by a STOPCD
dump. The program dumps on its default path (usually
[1,2]). The name of the first dump file is PSDMP.EXE. If
creating a new dump would overwrite a previous dump, then
the last SIXBIT character of the name will be incremented by
one until a unique name is found. The increment process
will continue through the next high order letters if that is
necessary. Thus, the second dump to be written would have
the name PSDMP!.EXE. Each STOPCD dump is accompanied by a
message to the operator which will also appear in ORION's
log file.
If any UUO necessary for the dump fails during stopcode
processing, then the program will halt and have to be dumped
and restarted manually.
Five types of STOPCDs are recognized:
1. STOP - The problem is a serious system failure and
the program will not continue. This usually occurs
if some UUO fails which never should. The program
will not try to reload itself due to the fact that
the failure probably won't go away.
2. RELOAD - A serious internal error occured, but it
is probably the fault of the PSTHRU program itself.
The program will reload, which will cause all
existing links to be aborted.
3. ABORT - The current link in which this problem
occured will be aborted. PSTHRU continues after
the link is aborted.
4. INFO - Something happened which may be worth
knowing about, but is probably not serious. PSTHRU
continues from the dump point as if nothing
happened.
5. NODUMP - Something happened which may be worth
knowing about, but it's not even serious enough to
warrant a dump file. PSTHRU continues normally.
The following is a list of the stopcodes which can occur.
1. Message: "Can't get core for initial buffers"
Type: STOP
PSTHRU.PLM Page 10
Program messages and stop codes
The CORE UUO to set up the initial BUFNUM buffers
failed.
2. Message: "Can't initialize PSISER"
Type: STOP
The PIINI. UUO to set up the priority software
interrupt system failed. See AC T1 for the error code.
3. Message: "Can't set up PSISER for NSP."
Type: STOP
The PISYS. UUO to add NSP. conditions to the priority
software interrupt system failed. Error code in T1.
4. Message: "Can't set initial DECnet link up"
Type: INFO
Routine DCNENT does an ENTER PASSIVE function to set up
a DECnet link. It returned non-skip, which means the
function failed. Error code to the NSP. UUO in T1. Note
that PSTHRU will not be accepting any DECnet connects if
this error occurs.
5. Message: "Can't set initial ANF link up"
Type: INFO
Routine ANFENT does an ENTER PASSIVE function to set up
an ANF link. It returned non-skip, which means the function
failed.
6. Message: "DEBRK. not implemented"
Type: STOP
A DEBRK. UUO failed with the non-skip return.
7. Message: "DECnet REJECT failed"
Type: INFO
A NSP. function to reject an incoming connect failed.
PSTHRU should only be trying to reject a connection if it
could not create an additional channel to have an
ever-present channel in connect wait, or if accepting the
connection failed. Error code for the NSP. UUO in T1.
8. Message: "DECnet Read Disconnect Information failed" Type:
Info
The .NSFRD function failed. Error code in T1.
9. Message: "DECnet RELEASE failed"
Type: INFO
PSTHRU.PLM Page 11
Program messages and stop codes
The .NSFRL function failed. Usually this means the
channel was already gone. Error code in T1.
10. Message: "Link isn't DECnet or ANF"
Type: RELOAD
PSTHRU can't determine whether a link is of type DECnet
or ANF. This implies the internal data base has been
trashed.
11. Message: "ANF RELEASE failed"
Type: INFO
A FILOP. to release an ANF channel failed. Probably
the channel was already released. The error code is in T1.
12. Message: "Can't turn PSISER on"
Type: STOP
A PISYS. UUO to turn the priority software interrupt
system back on failed. Error code in T1.
13. Message: "Can't turn PSISER off"
Type: STOP
A PISYS. UUO to turn the priority software interrupt
system off failed. Error code in T1.
14. Message: "DECnet READ NORMAL failed"
Type: ABORT
A NSP. function to read normal data from a DECnet link
failed. The error code is in T1. Data may have been lost.
15. Message: "DECnet READ INTERRRUPT failed"
Type: ABORT
A NSP. UUO to read interrupt data failed. Error code
in T3. Some data may have been lost.
16. Message: "DECnet buffer queued for write twice"
Type: RELOAD
The same buffer was queued for write twice on a given
link. This only occurs under FTDEBUG.
17. Message: "DECnet SEND INTERRUPT failed"
Type: ABORT
A NSP. function to send interrupt data failed. The
error code is in T1. Some data may be lost.
PSTHRU.PLM Page 12
Program messages and stop codes
18. Message: "DECnet SEND NORMAL failed"
Type: ABORT
The NSP. UUO to send normal data failed. Error code in
T1. Some data may have been lost.
19. Message: "Can't put TSK. link into IDLE state"
Type: INFO
The TSK. function to set a TSK link into idle state
failed. The error code is in T1. Actually, this can occur
under normal circumstances if the other side released the
link already.
20. Message: "I/O error on TSK. link"
Type: ABORT
A TSK link suffered an I/O error.
21. Message: "Can't add DECnet channel to the PI system"
Type: INFO
Routine DNPION which does the NSP. UUO to add a DECnet
channel to the priority software interrupt system didn't
skip. Note that the affected link half is probably dead.
22. Message: "Can't add ANF channel to the PI system"
Type: INFO
ANPION, which does the appropriate PISYS. UUO to add a
new ANF channel to the priority software interrupt system,
failed and didn't skip. Note that the affected link half is
probably dead.
23. Message: "Couldn't open log file, logging turned OFF"
Type: NODUMP
PSTHRU couldn't open the log file. This usually means
the appropriate logical name, PSTLOG, hasn't been defined.
Logging of events will not occur.
24. Message: "Logging output failed"
Type: INFO
An OUT UUO to the log file failed. The log file will
be closed.
25. Message: "CORE UUO failed"
Type: RELOAD
A CORE UUO to create more free core or buffers failed.
PSTHRU.PLM Page 13
Program messages and stop codes
26. Message: "Returning junk core block"
Type: RELOAD
This is only enabled under FTDEBUG. The core
de-allocator was called with either a base address of zero
or a length of zero to return to the free core pool.