Hi Muraoka, My solution is based on necessity more than RFC due to the limited number of bytes that I receive from the controller. I don't think I ever receive more than 128 bytes. Of which, only 81 bytes are ever sent to dhcy.py. So, I'm basically capturing what I can, since I figured it is better to be able to inspect most of the DHCP header fields rather than none at all. In hindsight, it may be better to throw out the sname as well (for inspections only). The field is still 64 bytes, but I'm only able to catch 40 bytes of it. Unless the useful information is contained in the first 40 bytes, then this solution is not so useful. But, I tried to capture as much information as possible given the buffer length I was receiving. I'm using an Open vSwitch on Mininet for my experiments. I'm not sure how many other SDN switches limit their packet headers to this extent, but I suspect many do.
That Mininet code is available at https://github.com/Ryuretic/RyureticLabs/ as well under mininet/examples/Ryuretic/DHCP_Topo.py. Thanks, Jacob https://www.linkedin.com/in/jacobcox74 -----Original Message----- From: Shinpei Muraoka [mailto:[email protected]] Sent: Thursday, December 22, 2016 12:15 AM To: [email protected] Cc: [email protected] Subject: Re: [Ryu-devel] Trouble parsing DHCP packets Hi, I am thinking of creating a patch using your source code. I have a question for your source code. The size of "sname" and "file" are defined by RFC 2131. ("sname" size is 64 bytes, "file" size is 128 bytes) In your source code there are cases where "sname" is 40 bytes and "file" does not exist. Did you create this code based on what? Also, Where is that case listed in RFC? Regards, Muraoka On 2016年12月22日 06:42, Jacob Cox wrote: > To make this work, I had to modify Ryu’s dhcp.py file. I just placed > my solution on stackoverflow, and I’m placing the complete file on > https://github.com/Ryuretic/RyureticLabs/tree/master/ryu/ryu/app/Ryure > tic/Support_Files shortly. Folks should be able to save their current > dhcp.py file as a backup and save my file to the packets folder. > > > > http://stackoverflow.com/questions/41244431/cant-parse-dhcp-packets-wi > th-ryus-get-protocoldhcp-dhcp/41272226#41272226 > > > > > > Respectfully, > > > > Jacob Cox > > > > > > ---------------------------------------------------------------------- > -------- Developer Access Program for Intel Xeon Phi Processors Access > to Intel Xeon Phi processor-based developer platforms. > With one year of Intel Parallel Studio XE. > Training and support from Colfax. > Order your platform today.http://sdm.link/intel > > > > _______________________________________________ > Ryu-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/ryu-devel > ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today.http://sdm.link/intel _______________________________________________ Ryu-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ryu-devel
