oconnor@SCCGATE.SCC.COM (Michael J. O'Connor) (03/16/88)
When our stock SMI DDN gateway attempted to forward IP-grams containing RR or LSRR options, it would crash. Our box is a 3/260 running SOS 3.5 and acts as a gateway between our local ethernet-based network and the ARPANET. We have only been able to test this behavior on outgoing packets, but if we are correct in our diagnosis, the problem should occur when the box attempts to forward any IP-option bearing packets in either direction. According to the engineer assigned to our service request, Sun has assigned the problem bug number 1008944 but will not supply a fix for 3.n SOS. He stated that the problem should be fixed in 4.0 SOS which will be distributed later in 1988. Based on a report from Allison Mankin of MITRE, that the crashing is caused by a previously reported typo in ip_stripoption(), I have patched our binary in an attempt to reverse the effects of the typo. The patch has been working now for a little over 2 weeks. Working in the sense that our machine no longer crashes when forwarding IPgrams which contain options. I have yet to verify what is going out the other interface. If anyone else is affected by this, and the legal boys allow it, I am willing to supply the binary patch. It only consists of modifying a register value in 2 consecutive instructions. Mike
kwe@bu-cs.BU.EDU (kwe@bu-it.bu.edu (Kent W. England)) (03/18/88)
In article <8803151852.AA12900@sccgate.scc.com> oconnor@SCCGATE.SCC.COM (Michael J. O'Connor) writes: >When our stock SMI DDN gateway attempted to forward IP-grams containing RR or >LSRR options, it would crash. Our box is a 3/260 running SOS 3.5 and acts as >a gateway between our local ethernet-based network and the ARPANET. > >Based on a report from Allison Mankin of MITRE, that the crashing is caused by >a previously reported typo in ip_stripoption(), I have patched our binary in an >attempt to reverse the effects of the typo. The patch has been working now for >a little over 2 weeks. It seems that IP RR and LSRR options will crash a lot of gateways. I would like to hear from others how widespread the problem is (other known implementation failures) and what they think the utility of RR and LSRR is for debugging and network management. Seems to me that record route and loose source routing options would be extremely useful for checking router tables without actually doing a netstat or equivalent. However, if there are too many routers that crash or don't record themselves or follow the route request, then such an option is unusable. I have never read a conversation on this in tcp-ip. Anyone able to make use of IP route options? If so, how useful is it?
oconnor@SCCGATE.SCC.COM (Michael J. O'Connor) (03/19/88)
Maybe I should have worded it differently. It's my contention that a Sun gateway running a version of SOS earlier than 4.0 can crash when it attempts to forward any option bearing datagram not just the record route types. The only option generating software that I have access to is the Ping with RR and LSRR which was described in this forum a month or so ago. People were crashing our gateway every time they tried to send one of those packets through our SMI box. Excuse my pontificating, but it is the presence of IP-options that is optional not the implementation. I don't have a copy of the Mil-Std handy but my copy of the RFC states "Every internet module must be able to act on every option." I just don't think that crashing was the act that the authors had in mind. The part that still irritates me is SMI's attitude that this is a bug that I should be able to live with until they release SOS 4.0. On top of that there is the rumor that the Sunlink DDN package will not be updated until well after the 4.0 release. If true, that means our gateway will be the last machine upgradable to SOS 4.0. Mike
S72TDAN@TOWSONVX.BITNET (DAN) (03/19/88)
I'M NOT TOO SURE ON HOW TO SEND A MAIL MESSAGE SO I'M DOING IT THIS WAY.
PLEASE UNSUSCRIBE ME FROM LIST TCP-IP.cpw%sneezy@LANL.GOV (C. Philip Wood) (03/19/88)
I have found IP options and ICMP functions useful. I also feel that if they crash gateways, then the gateway should be replaced darned quick. I also think that users planning on joining or doing an Internet should become familiar with RFC1009 which explicitly states that Record Route, Loose and Strict Source Route,among the others, are required for gateways. OPTION does not mean its up to the discretion of the Vendor, only that it may or may not be in an IP header! We are planning to use the IP Security Option, or son of ... You bet the IP options are important. A vendor who's product does not work correctly will not be looked on kindly from here. cornett philip wood (cpw@lanl.gov) Los Alamos National Laboratory
GRAVES@MATHOM.CISCO.COM (Bill Graves) (03/19/88)
IP options are not optional for IP Gateways! -------