In a program I'm writing I have a network namespace with a virtual (TAP) network interface assigned to it. I would like it so that the interface is automatically destroyed when the namespace is destroyed (ie. when the last process in the namespace exits). I can't see any way to implement this..

I believe (although I can't find the relevant documentation right now) that when a namespace is destroyed all its interfaces are moved to the root namespace. If this is the case, is there anyway to detect when a namespace is moved so that I can close it manually? Alternatively, is there a way to detect when a namespace is destroyed? How about just when a process exits? Basically I'm looking for any event the Linux kernel can give me that I can use to implement what I want.

The only way I can see of doing this is using inotify on the one of the directories under /proc or /sys, but that seems really hacky and racy. Does linuxquestions have any better ideas?

I have not written any network namespace aware programs, but as no one else has stepped up I'll try to get things moving for you.

First off, when asking programming questions it is always helpful to others to mention the language you are using, and the OS and/or distro you are working with. Different languages will have differing support functions and libs available which will affect the replies you may receive - especially true of networking applications. Early on, different distros offered differing support for network namespaces, or none at all, but I am not sure how that may have changed in the past few years.

Looking for online help I found plenty of resources available, some of which may surely have the answer you want. One of the best I think after a quick browse was thie OpenStack article: Network Namespaces. Use your search engine of choice to find others.

Finally, if you do not receive useful replies in the Programming forum, you might want to have your question moved to the Netowrking forum. If you want to have it moved simply click the Report button at bottom of your post and ask a moderator to do that for you.

Good luck!