Re: Networking Patches

Alan Cox (alan@cymru.net)
Thu, 6 Jun 1996 10:00:18 +0100 (BST)


> Please give more safety margin for vger delays. I got this on Thursday.
> Unless you mean "next Thursday" :-).

This thursday

> Especially CONFIG_INET_PCTCP and CONFIG_NO_PATH_MTU_DISCOVERY - so that
> you don't have to recompile after you discover some broken software in
> use on the network.

Ok added to the fun ideas for 2.1 queue

> available). There are no more bridges on this network, just this one.
> Any chances that it will work? What are the problems should I expect?
> Or am I better off using PCbridge for DOS? (the Linux box is needed
> there anyway for other reasons, so it would be better to make it work
> as a bridge too)

PCbridge and kbridge are nice, and run on an old 286 even. The current
bridge code doesnt seem to want to work properly. I've got to set up a
home network bridged to track it down and that will be after 2.0.

> I often get the IPX network number collision messages on the console.
> This happens on three completely different novell networks so I don't
> believe they are all misconfigured - maybe change the priority of
> the messages so they don't show up on the console but only in syslog.

There was a fix for some of this in .10 or so where it used to do very
stupid things with network 0 (claiming it collided) and not realising
0 is "this network". The other problem is people using the same network
number of all the media types which is wrong.

> I think there is a potential memory leak in net/core/net_alias.c
> (net_alias_dev_create) if the first kmalloc succeeds but the second
> one fails (won't free memory allocated by the first).

Will check tonight

> get_empty_filp() should reserve a few last files (tunable?) for the
> superuser - otherwise a simple denial of service is possible. Just
> fork 4 processes, have each of them try to open 256 file descriptors
> - and almost everything stops working. No heavy swapping necessary.

Not a bad idea. Linus ?

> Sometimes I get "deleted inode XX has zero dtime" from e2fsck even
> though the system was shut down cleanly. Is this something to
> worry about? I saw this in early 1.1.x days for the first time,
> and it's still there...

Pass

> The kmalloc return value not checked for NULL in net/unix/af_unix.c
> (unix_copyrights, unix_attach_fds). If it fails - oops.

GFP_KERNEL never fails. If it does a lot of the machine breaks. The
fact its checked is more history than anything else.

Alan