jamal <hadi@xxxxxxxxxx> writes:
> On Mon, 2010-02-22 at 15:17 -0800, Eric W. Biederman wrote:
>
>> What I am thinking is:
>>
>> "ip ns <name> route add blah" is:
>> fd = open("/var/run/netns/<name>");
>> sys_setns(fd); /* Like unshare but takes an existing namespace */
>> /* Then the rest of the existing ip command */
>
> The other two below make some sense; For the above:
> Does the point after sys_setns(fd) allow me to do io inside
> ns <name>? Can i do open() and get a fd from ns <name>?
Yes. My intention is that current->nsproxy->net_ns be changed.
We can already change it in unshare so this is feasible.
>> "ip ns list" is:
>> dfd = open("/var/run/netns", O_DIRECTORY);
>> getdents(dfd, buf, count);
>>
>> "ip ns new <name>" is:
>> unshare(CLONE_NEWNS);
>> fd = nsfd(NETNS);
>> mkdir("/var/run/netns/<name>");
>> mount("none", "/var/run/netns/<name>", "ns", 0, fd);
>>
>> Using unix domain names means that which namespaces you see is under
>> control of userspace. Which allows for nested containers (something I
>> use today), and ultimately container migration.
>
> The only problem that i see is events are not as nice. I take it i am
> going to get something like an inotify when a new namespace is created?
Yes. Inotify would at the very least see that mkdir. You could also
use poll on /proc/mounts to see the set of mounts change.
>> Using genetlink userspace doesn't result in a nestable implementation
>> unless I introduce yet another namespace, ugh.
>
> Is it not just a naming convention that you are dealing with?
> Example in your scheme above a nested namespace shows up as:
> /var/run/netns/<name>/<nestedname>, no?
No. More like:
For the outer namespace:
/var/run/netns/<name>
For the inner namespace:
/some/random/fs/path/to/a/chroot/var/run/netns/<name>
For a doubly nested scenario:
/some/random/fs/path/to/a/chroot/some/other/random/fs/path/to/another/chroot/var/run/netns/<name>
Since I would be using mount namespaces instead of chroot it is not
strictly required that the fs paths nest at all.
Eric
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
