This is the second issue; the information below is the start of what has been collected here. It is expected that more information will be collected in the next few weeks, and that information will be forwarded when/if it becomes available. ===================================================== -- part 1 ===================================================== This information came via several people, most of whom snet this exact message (probably from their news archives from before we joined the net): I am posting this over the network because I believe that others are interested in knowing the protocols of UUCP. Below is listed all the information that I have acquired to date. This includes the initial handshaking phase, though not the login phase. It also doesn't include information about the data transfer protocol for non-packet networks (the -G option left off the uucico command line). But, just hold on - I am working on that stuff. For a point of information : the slave is the UUCP site being dialed, and the master is the one doing the calling up. The protocols listed in the handshaking and termination phase are independent of any UUCP site : it is universal. The stuff in the work phase depends on the specific protocol chosen. The concepts in the work phase are independent of protocol, ie. the sequences are the same. It is just the lower level stuff that changes from protocol to protocol. I have access only to level g and will document it as I begin to understand it. Most of the stuff you see here is gotten from the debug phase of the current BSD UUCP system. I hope this is useful. Maybe this will get some of the real 'brains' in UUCP to get off their duffs and provide some real detail. In any case, if you have any questions please feel free to contact me. I will post any questions and answers over the network. Chuck Wegrzyn {allegra,decvax,ihnp4}!encore!wegrzyn (617) 237-1022 UUCP Handshake Phase ==================== Master Slave ------ ----- <----- \020Shere\0 (1) (2) \020S \0 -----> <----- \020RLCK\0 (3) \020RCB\0 \020ROK\0 \020RBADSEQ\0 <----- \020P\0 (4) (5) \020U\0 -----> \020UN\0 (6) ... (0) This communication happens outside of the packet communication that is supported. If the -G flag is sent on the uucico line, all communications will occur without the use of the packet simulation software. The communication at this level is just the characters listed above. (1) The slave sends the sequence indicated, while the master waits for the message. (2) The slave waits for the master to send a response message. The message is composed of the master's name and some optional switches. The switch field can include the following -g (set by the -G switch on the master's uucico command line. Indicates that communication occurs over a packet switch net.) -xN (set by the -x switch on the master's uucico command line. The number N is the debug level desired.) -QM (M is really a sequence number for the communication.) Each switch is separated from the others by a 'blank' character. (3) The slave will send one of the many responses. The meanings appear to be : RLCK This message implies that a 'lock' failure occurred: a file called LCK..mastername couldn't be created since one already exists. This seems to imply that the master is already in communication with the slave. RCB This message will be sent out if the slave requires a call back to the master - the slave will not accept a call from the master but will call the master instead. ROK This message will be returned if the sequence number that was sent in the message, attached to the -Q switch, from the master is the same as that computed on the slave. RBADSEQ Happens if the sequence numbers do not match. (Notes on the sequence number - if a machine does not keep sequence numbers, the value is set to 0. If no -Q switch is given in the master's line, the sequence number is defaulted to 0. The sequence file, SQFILE, has the format /-: where is the name of a master and is the previous sequence number. If the field is not present, or if it is greater than 9998, it is set to 0. The field is an ascii representation of the number. The stuff after the is the time the sequence number was last changed, this information doesn't seem important.) (4) The slave sends a message that identifies all the protocols that it supports. It seems that BSD supports 'g' as the normal case. Some sites, such as Allegra, support 'e' and 'g', and a few sites support 'f' as well. I have no information about these protocols. The exact message sent might look like \020Pefg\0 where efg indicates that this slave supports the e,f and g protocols. (5) The slave waits for a response from the master with the chosen protocol. If the master has a protocol that is in common the master will send the message \020U\0 where is the protocol (letter) chosen. If no protocol is in common, the master will send the message \020UN\0 (6) At this point both the slave and master agree to use the designated protocol. The first thing that now happens is that the master checks for work. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ UUCP Work Phase =============== Master Slave ------ ----- (a) Master has UUCP Work (1) X file1 file2 -----> <----- XN (2) XY When the master wants the slave to do a 'uux' command it sends the X message. If the slave can't or won't do it, the slave will send an XN message. Otherwise it will send an XY message. (b) Master wants to send a file (1) S file1 file2 user options -----> <----- SN2 (2) SN4 SY <---- ----> (3) <----- CY (4) CN5 If the master wishes to send a file to the slave, it will send a S message to the slave. If the slave can or will do the transfer, it sends a SY message. If the slave has a problem creating work files, it sends a SN4 message. If the target file can't be created (because of priv's etc) it sends a SN2 message. The file1 argument is the source file, and file2 is the (almost) target filename. If file2 is a directory, then the target filename is composed of file2 concatenated with the "last" part of the file1 argument. Note, if the file2 argument begins with X, the request is targeted to UUX and not the normal send. The user argument indicates who, if anyone, is to be notified if the file has been copied. This user must be on the slave system. I am not sure what the options argument does. After the data has been exchanged the slave will send one of two messages to the master. A CY message indicates that every- thing is ok. The message CN5 indicates that the slave had some problem moving the file to it's permanent location. This is not the same as a problem during the exchange of data : this causes the slave to terminate operation. (c) Master wishes to receive a file. (1) R file1 file2 user -----> <----- RN2 (2) RY mode (3) <---- ----> (4) CY -----> CN5 If the master wishes the slave to send a file, the master sends a R message. If the slave has the file and can send it, the slave will respond with the RY message. If the slave can't find the file, or won't send it the RN2 message is sent. It doesn't appear that the 'mode' field of the RY message is used. The argument file1 is the file to transfer, unless it is a directory. In this case the file to be transferred is built of a concatenation of file1 with the "last" part of the file2 argument. If anything goes wrong with the data transfer, it results in both the slave and the master terminating. After the data has been transferred, the master will send an acknowledgement to the slave. If the transfer and copy to the destination file has been successful, the master will send the CY message. Otherwise it will send the CN5 message. (d) Master has no work, or no more work. (1) H -----> <----- HY (2) HN (3) HY -----> <---- HY (4) (5) ... The transfer of control is initiated with the master sending a H message. This message tells the slave that the master has no work, and the slave should look for work. If the slave has no work it will respond with the HY message. This will tell the master to send an HY message, and turn off the selected protocol. When the HY message is received by the slave, it turns off the selected protocol as well. Both the master and slave enter the UUCP termination phase. If the slave does have work, it sends the HN message to the master. At this point, the slave becomes the master. After the master receives the HN message, it becomes the slave. The whole sequence of sending work starts over again. Note, the transmission of HN doesn't force the master to send any other H messages : it waits for stuff from the new master. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ UUCP Termination Sequence ========================= Master Slave ------ ----- (1) \020OOOOOO\0 -----> <----- \020OOOOOOO\0 (2) At this point all conversation has completed normally. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ UUCP Data Transfers =================== After the initial handshake the systems send messages in one of two styles : packet and not packet. A Packet protocol is just raw data transfers : there is no protocol or acknowledgements; this appears to assume that the lower level is a packet network of some type. If the style is not Packet, then extra work is done. I am still working on this stuff. ===================================================== -- part 2 ===================================================== ** summary of UUCP packets ** (this is much like part 1, but shortened and compared against a live UUCP ~uucp_adm/uucico) note that all transmissions end with a null, not shown here (master) (slave) ... dials up ... Shere says "hello" S says who he is | ROK says ok to talk | RLCK says locked out | RCB says will call back | RBADSEQ says bad seq num P what protocols he has U | which to use UN | use none, hang up packet driver is turned on at this time, if not told otherwise -- if master has work -- to sned file to slave... S request to sned file | SY ok -- i'll take it | SN2 not permitted | SN4 can't make workfile the file is transmitted | CY finished OK | CN5 can't move into place to recv file from slave... R request to recv file | RY ok -- here is prot mode | RN2 not permitted file is transmitted CY | worked CN5 | can't move into place to do UUX on slave... X request to exec file | XY ok -- will do | XN nopers to indicate that he has no more work... H no more work | HN reverse roles | HY no work here either to accept slave's claim of no more work... HY agrees to hang up the rest of the hang-up is done OUTSIDE of packet driver OOOOOO signs off (6*'O') OOOOOOO signs off (7*'O') If the slave has work, then the roles are reversed, and the session proceeds from the label 'loop1' above. The system which was the slave is now the master, and the old master is just the slave. The which follow the system name for the start-up sequence include: -g don't use packet driver (command line -G) -xN debug level (command line -Xn) -QN seq number (if systems use this) The filenames for should be complete filenames with path information; otherwise they are assumed to be in /usr/spool/uucp. The filenames for should be either complete filenames or directory names. If directory names are used, then the final componant of is appended to form the complete filename. The 'X' command to do UUX on a slave is more than a little unclear. It doesn't seem to work here, but that may be a microsoft "feature". Protocol "g", which seems to be the one most commonly used, is supposed to be a slightly munged version of level 2 of X.25; an article was just posted in net.unix-wizards (which you probably have already seen) to this effect. The article didn't provide any details on the protocol, but merely mentioned the modifications. The "packet" mode, with no protocol, does not work under microsoft implementations, and may have *lots* of trouble working anywhere else as well. It evidently requires that zero-length reads happen every so often to delimit things, such as files being transferred. This of course can't happen without the packet driver, which was long gone by the time sys-3 or sys-5 or came along. ********************************** ** end of issue #2 **********************************