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diff --git a/usr.bin/telnet/README b/usr.bin/telnet/README new file mode 100644 index 0000000..086c88f --- /dev/null +++ b/usr.bin/telnet/README @@ -0,0 +1,566 @@ + + +This is a distribution of both client and server telnet. These programs +have been compiled on: + telnet telnetd + BSD 4.3 Reno X X + UNICOS 5.1 X X + UNICOS 6.0 X X + UNICOS 6.1 X X + UNICOS 7.0 X X + SunOs 3.5 X X (no linemode in server) + SunOs 4.1 X X (no linemode in server) + DYNIX V3.0.17.9 X X (no linemode in server) + Ultrix 3.1 X X (no linemode in server) + Ultrix 4.0 X X (no linemode in server) + +In addition, previous versions have been compiled on the following +machines, but were not available for testing this version. + telnet telnetd + SunOs 4.0.3c X X (no linemode in server) + BSD 4.3 X X (no linemode in server) + DYNIX V3.0.12 X X (no linemode in server) + +Februrary 22, 1991: + + Features: + + This version of telnet/telnetd has support for both + the AUTHENTICATION and ENCRYPTION options. The + AUTHENTICATION option is fairly well defined, and + an option number has been assigned to it. The + ENCRYPTION option is still in a state of flux; an + option number has NOT been assigned to it yet. + The code is provided in this release for experimental + and testing purposes. + + The telnet "send" command can now be used to send + do/dont/will/wont commands, with any telnet option + name. The rules for when do/dont/will/wont are sent + are still followed, so just because the user requests + that one of these be sent doesn't mean that it will + be sent... + + The telnet "getstatus" command no longer requires + that option printing be enabled to see the response + to the "DO STATUS" command. + + A -n flag has been added to telnetd to disable + keepalives. + + A new telnet command, "auth" has been added (if + AUTHENTICATE is defined). It has four sub-commands, + "status", "debug", "disable", "enable" and "help". + + A new telnet command, "encrypt" has been added (if + ENCRYPT is defined). It has many sub-commands: + "enable", "type", "start", "stop", "input", + "-input", "output", "-output", "status", "auto", + "verbose", "debug", and "help". + + An "rlogin" interface has been added. If the program + is named "rlogin", or the "-r" flag is given, then + an rlogin type of interface will be used. + ~. Terminates the session + ~<susp> Suspend the session + ~^] Escape to telnet command mode + ~~ Pass through the ~. + BUG: If you type the rlogin escape character + in the middle of a line while in rlogin + mode, you cannot erase it or any characters + before it. Hopefully this can be fixed + in a future release... + + General changes: + + A "libtelnet.a" has now been created. This libraray + contains code that is common to both telnet and + telnetd. This is also where library routines that + are needed, but are not in the standard C library, + are placed. + + The makefiles have been re-done. All of the site + specific configuration information has now been put + into a single "Config.generic" file, in the top level + directory. Changing this one file will take care of + all three subdirectories. Also, to add a new/local + definition, a "Config.local" file may be created + at the top level; if that file exists, the subdirectories + will use that file instead of "Config.generic". + + Many 1-2 line functions in commands.c have been + removed, and just inserted in-line, or replaced + with a macro. + + Bug Fixes: + + The non-termio code in both telnet and telnetd was + setting/clearing CTLECH in the sg_flags word. This + was incorrect, and has been changed to set/clear the + LCTLECH bit in the local mode word. + + The SRCRT #define has been removed. If IP_OPTIONS + and IPPROTO_IP are defined on the system, then the + source route code is automatically enabled. + + The NO_GETTYTAB #define has been removed; there + is a compatability routine that can be built into + libtelnet to achive the same results. + + The server, telnetd, has been switched to use getopt() + for parsing the argument list. + + The code for getting the input/output speeds via + cfgetispeed()/cfgetospeed() was still not quite + right in telnet. Posix says if the ispeed is 0, + then it is really equal to the ospeed. + + The suboption processing code in telnet now has + explicit checks to make sure that we received + the entire suboption (telnetd was already doing this). + + The telnet code for processing the terminal type + could cause a core dump if an existing connection + was closed, and a new connection opened without + exiting telnet. + + Telnetd was doing a TCSADRAIN when setting the new + terminal settings; This is not good, because it means + that the tcsetattr() will hang waiting for output to + drain, and telnetd is the only one that will drain + the output... The fix is to use TCSANOW which does + not wait. + + Telnetd was improperly setting/clearing the ISTRIP + flag in the c_lflag field, it should be using the + c_iflag field. + + When the child process of telnetd was opening the + slave side of the pty, it was re-setting the EXTPROC + bit too early, and some of the other initialization + code was wiping it out. This would cause telnetd + to go out of linemode and into single character mode. + + One instance of leaving linemode in telnetd forgot + to send a WILL ECHO to the client, the net result + would be that the user would see double character + echo. + + If the MODE was being changed several times very + quickly, telnetd could get out of sync with the + state changes and the returning acks; and wind up + being left in the wrong state. + +September 14, 1990: + + Switch the client to use getopt() for parsing the + argument list. The 4.3Reno getopt.c is included for + systems that don't have getopt(). + + Use the posix _POSIX_VDISABLE value for what value + to use when disabling special characters. If this + is undefined, it defaults to 0x3ff. + + For non-termio systems, TIOCSETP was being used to + change the state of the terminal. This causes the + input queue to be flushed, which we don't want. This + is now changed to TIOCSETN. + + Take out the "#ifdef notdef" around the code in the + server that generates a "sync" when the pty oputput + is flushed. The potential problem is that some older + telnet clients may go into an infinate loop when they + receive a "sync", if so, the server can be compiled + with "NO_URGENT" defined. + + Fix the client where it was setting/clearing the OPOST + bit in the c_lflag field, not the c_oflag field. + + Fix the client where it was setting/clearing the ISTRIP + bit in the c_lflag field, not the c_iflag field. (On + 4.3Reno, this is the ECHOPRT bit in the c_lflag field.) + The client also had its interpretation of WILL BINARY + and DO BINARY reversed. + + Fix a bug in client that would cause a core dump when + attempting to remove the last environment variable. + + In the client, there were a few places were switch() + was being passed a character, and if it was a negative + value, it could get sign extended, and not match + the 8 bit case statements. The fix is to and the + switch value with 0xff. + + Add a couple more printoption() calls in the client, I + don't think there are any more places were a telnet + command can be received and not printed out when + "options" is on. + + A new flag has been added to the client, "-a". Currently, + this just causes the USER name to be sent across, in + the future this may be used to signify that automatic + authentication is requested. + + The USER variable is now only sent by the client if + the "-a" or "-l user" options are explicity used, or + if the user explicitly asks for the "USER" environment + variable to be exported. In the server, if it receives + the "USER" environment variable, it won't print out the + banner message, so that only "Password:" will be printed. + This makes the symantics more like rlogin, and should be + more familiar to the user. (People are not used to + getting a banner message, and then getting just a + "Password:" prompt.) + + Re-vamp the code for starting up the child login + process. The code was getting ugly, and it was + hard to tell what was really going on. What we + do now is after the fork(), in the child: + 1) make sure we have no controlling tty + 2) open and initialize the tty + 3) do a setsid()/setpgrp() + 4) makes the tty our controlling tty. + On some systems, #2 makes the tty our controlling + tty, and #4 is a no-op. The parent process does + a gets rid of any controlling tty after the child + is fork()ed. + + Use the strdup() library routine in telnet, instead + of the local savestr() routine. If you don't have + strdup(), you need to define NO_STRDUP. + + Add support for ^T (SIGINFO/VSTATUS), found in the + 4.3Reno distribution. This maps to the AYT character. + You need a 4-line bugfix in the kernel to get this + to work properly: + + > *** tty_pty.c.ORG Tue Sep 11 09:41:53 1990 + > --- tty_pty.c Tue Sep 11 17:48:03 1990 + > *************** + > *** 609,613 **** + > if ((tp->t_lflag&NOFLSH) == 0) + > ttyflush(tp, FREAD|FWRITE); + > ! pgsignal(tp->t_pgrp, *(unsigned int *)data); + > return(0); + > } + > --- 609,616 ---- + > if ((tp->t_lflag&NOFLSH) == 0) + > ttyflush(tp, FREAD|FWRITE); + > ! pgsignal(tp->t_pgrp, *(unsigned int *)data, 1); + > ! if ((*(unsigned int *)data == SIGINFO) && + > ! ((tp->t_lflag&NOKERNINFO) == 0)) + > ! ttyinfo(tp); + > return(0); + > } + + The client is now smarter when setting the telnet escape + character; it only sets it to one of VEOL and VEOL2 if + one of them is undefined, and the other one is not already + defined to the telnet escape character. + + Handle TERMIOS systems that have seperate input and output + line speed settings imbedded in the flags. + + Many other minor bug fixes. + +June 20, 1990: + Re-organize makefiles and source tree. The telnet/Source + directory is now gone, and all the source that was in + telnet/Source is now just in the telnet directory. + + Seperate makefile for each system are now gone. There + are two makefiles, Makefile and Makefile.generic. + The "Makefile" has the definitions for the various + system, and "Makefile.generic" does all the work. + There is a variable called "WHAT" that is used to + specify what to make. For example, in the telnet + directory, you might say: + make 4.4bsd WHAT=clean + to clean out the directory. + + Add support for the ENVIRON and XDISPLOC options. + In order for the server to work, login has to have + the "-p" option to preserve environment variables. + + Add the SOFT_TAB and LIT_ECHO modes in the LINEMODE support. + + Add the "-l user" option to command line and open command + (This is passed through the ENVIRON option). + + Add the "-e" command line option, for setting the escape + character. + + Add the "-D", diagnostic, option to the server. This allows + the server to print out debug information, which is very + useful when trying to debug a telnet that doesn't have any + debugging ability. + + Turn off the literal next character when not in LINEMODE. + + Don't recognize ^Y locally, just pass it through. + + Make minor modifications for Sun4.0 and Sun4.1 + + Add support for both FORW1 and FORW2 characters. The + telnet escpape character is set to whichever of the + two is not being used. If both are in use, the escape + character is not set, so when in linemode the user will + have to follow the escape character with a <CR> or <EOF) + to get it passed through. + + Commands can now be put in single and double quotes, and + a backslash is now an escape character. This is needed + for allowing arbitrary strings to be assigned to environment + variables. + + Switch telnetd to use macros like telnet for keeping + track of the state of all the options. + + Fix telnetd's processing of options so that we always do + the right processing of the LINEMODE option, regardless + of who initiates the request to turn it on. Also, make + sure that if the other side went "WILL ECHO" in response + to our "DO ECHO", that we send a "DONT ECHO" to get the + option turned back off! + + Fix the TERMIOS setting of the terminal speed to handle both + BSD's seperate fields, and the SYSV method of CBAUD bits. + + Change how we deal with the other side refusing to enable + an option. The sequence used to be: send DO option; receive + WONT option; send DONT option. Now, the sequence is: send + DO option; receive WONT option. Both should be valid + according to the spec, but there has been at least one + client implementation of telnet identified that can get + really confused by this. (The exact sequence, from a trace + on the server side, is (numbers are number of responses that + we expect to get after that line...): + + send WILL ECHO 1 (initial request) + send WONT ECHO 2 (server is changing state) + recv DO ECHO 1 (first reply, ok. expect DONT ECHO next) + send WILL ECHO 2 (server changes state again) + recv DONT ECHO 1 (second reply, ok. expect DO ECHO next) + recv DONT ECHO 0 (third reply, wrong answer. got DONT!!!) + *** send WONT ECHO (send WONT to acknowledge the DONT) + send WILL ECHO 1 (ask again to enable option) + recv DO ECHO 0 + + recv DONT ECHO 0 + send WONT ECHO 1 + recv DONT ECHO 0 + recv DO ECHO 1 + send WILL ECHO 0 + (and the last 5 lines loop forever) + + The line with the "***" is last of the WILL/DONT/WONT sequence. + The change to the server to not generate that makes this same + example become: + + send will ECHO 1 + send wont ECHO 2 + recv do ECHO 1 + send will ECHO 2 + recv dont ECHO 1 + recv dont ECHO 0 + recv do ECHO 1 + send will ECHO 0 + + There is other option negotiation going on, and not sending + the third part changes some of the timings, but this specific + example no longer gets stuck in a loop. The "telnet.state" + file has been modified to reflect this change to the algorithm. + + A bunch of miscellaneous bug fixes and changes to make + lint happier. + + This version of telnet also has some KERBEROS stuff in + it. This has not been tested, it uses an un-authorized + telnet option number, and uses an out-of-date version + of the (still being defined) AUTHENTICATION option. + There is no support for this code, do not enable it. + + +March 1, 1990: +CHANGES/BUGFIXES SINCE LAST RELEASE: + Some support for IP TOS has been added. Requires that the + kernel support the IP_TOS socket option (currently this + is only in UNICOS 6.0). + + Both telnet and telnetd now use the cc_t typedef. typedefs are + included for systems that don't have it (in termios.h). + + SLC_SUSP was not supported properly before. It is now. + + IAC EOF was not translated properly in telnetd for SYSV_TERMIO + when not in linemode. It now saves a copy of the VEOF character, + so that when ICANON is turned off and we can't trust it anymore + (because it is now the VMIN character) we use the saved value. + + There were two missing "break" commands in the linemode + processing code in telnetd. + + Telnetd wasn't setting the kernel window size information + properly. It was using the rows for both rows and columns... + +Questions/comments go to + David Borman + Cray Research, Inc. + 655F Lone Oak Drive + Eagan, MN 55123 + dab@cray.com. + +README: You are reading it. + +Config.generic: + This file contains all the OS specific definitions. It + has pre-definitions for many common system types, and is + in standard makefile fromat. See the comments at the top + of the file for more information. + +Config.local: + This is not part of the distribution, but if this file exists, + it is used instead of "Config.generic". This allows site + specific configuration without having to modify the distributed + "Config.generic" file. + +kern.diff: + This file contains the diffs for the changes needed for the + kernel to support LINEMODE is the server. These changes are + for a 4.3BSD system. You may need to make some changes for + your particular system. + + There is a new bit in the terminal state word, TS_EXTPROC. + When this bit is set, several aspects of the terminal driver + are disabled. Input line editing, character echo, and + mapping of signals are all disabled. This allows the telnetd + to turn of these functions when in linemode, but still keep + track of what state the user wants the terminal to be in. + + New ioctl()s: + + TIOCEXT Turn on/off the TS_EXTPROC bit + TIOCGSTATE Get t_state of tty to look at TS_EXTPROC bit + TIOCSIG Generate a signal to processes in the + current process group of the pty. + + There is a new mode for packet driver, the TIOCPKT_IOCTL bit. + When packet mode is turned on in the pty, and the TS_EXTPROC + bit is set, then whenever the state of the pty is changed, the + next read on the master side of the pty will have the TIOCPKT_IOCTL + bit set, and the data will contain the following: + struct xx { + struct sgttyb a; + struct tchars b; + struct ltchars c; + int t_state; + int t_flags; + } + This allows the process on the server side of the pty to know + when the state of the terminal has changed, and what the new + state is. + + However, if you define USE_TERMIO or SYSV_TERMIO, the code will + expect that the structure returned in the TIOCPKT_IOCTL is + the termio/termios structure. + +stty.diff: + This file contains the changes needed for the stty(1) program + to report on the current status of the TS_EXTPROC bit. It also + allows the user to turn on/off the TS_EXTPROC bit. This is useful + because it allows the user to say "stty -extproc", and the + LINEMODE option will be automatically disabled, and saying "stty + extproc" will re-enable the LINEMODE option. + +telnet.state: + Both the client and server have code in them to deal + with option negotiation loops. The algorithm that is + used is described in this file. + +tmac.doc: + Macros for use in formatting the man pages on non-4.3Reno + systems. + +telnet: + This directory contains the client code. No kernel changes are + needed to use this code. + +telnetd: + This directory contains the server code. If LINEMODE or KLUDGELINEMODE + are defined, then the kernel modifications listed above are needed. + +libtelnet: + This directory contains code that is common to both the client + and the server. + +arpa: + This directory has a new <arpa/telnet.h> + + +The following TELNET options are supported: + + LINEMODE: + The LINEMODE option is supported as per RFC1116. The + FORWARDMASK option is not currently supported. + + BINARY: The client has the ability to turn on/off the BINARY + option in each direction. Turning on BINARY from + server to client causes the LITOUT bit to get set in + the terminal driver on both ends, turning on BINARY + from the client to the server causes the PASS8 bit + to get set in the terminal driver on both ends. + + TERMINAL-TYPE: + This is supported as per RFC1091. On the server side, + when a terminal type is received, termcap/terminfo + is consulted to determine if it is a known terminal + type. It keeps requesting terminal types until it + gets one that it recongnizes, or hits the end of the + list. The server side looks up the entry in the + termcap/terminfo data base, and generates a list of + names which it then passes one at a time to each + request for a terminal type, duplicating the last + entry in the list before cycling back to the beginning. + + NAWS: The Negotiate about Window Size, as per RFC 1073. + + TERMINAL-SPEED: + Implemented as per RFC 1079 + + TOGGLE-FLOW-CONTROL: + Implemented as per RFC 1080 + + TIMING-MARK: + As per RFC 860 + + SGA: As per RFC 858 + + ECHO: As per RFC 857 + + STATUS: + The server will send its current status upon + request. It does not ask for the clients status. + The client will request the servers current status + from the "send getstatus" command. + + ENVIRON: + This option is currently being defined by the IETF + Telnet Working Group, and an RFC has not yet been + issued, but should be in the near future... + + X-DISPLAY-LOCATION: + This functionality can be done through the ENVIRON + option, it is added here for completeness. + + AUTHENTICATION: + This option is currently being defined by the IETF + Telnet Working Group, and an RFC has not yet been + issued. The basic framework is pretty much decided, + but the definitions for the specific authentication + schemes is still in a state of flux. + + ENCRYPT: + This option is currently being defined by the IETF + Telnet Working Group, and an RFC has not yet been + issued. The draft RFC is still in a state of flux, + so this code may change in the future. |
