From: Igor Ryzhov <iryzhov@nfware.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: Dan Gora <dg@adax.com>, Ferruh Yigit <ferruh.yigit@intel.com>,
dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v2 10/10] kni: add API to set link status on kernel interface
Date: Thu, 30 Aug 2018 12:49:47 +0300 [thread overview]
Message-ID: <CAF+s_Fx=x8wO5Ygxr4sxUj2G1hh+dRyFr7XiwYHL4SUPRNhX4g@mail.gmail.com> (raw)
In-Reply-To: <20180829161043.11bb2434@xeon-e3>
Hi Dan,
We use KNI device exactly the same way you described – with IP addresses,
routing, etc.
And we also faced the same problem of having the actual link status in
Linux kernel.
There is a special callback for link state management in net_device_ops for
soft-devices like KNI called ndo_change_carrier.
Current KNI driver implements it already, you just need to write to
/sys/class/net/<iface>/carrier
to change link status.
Right now we implement it on application side, but I think it'll be good to
have this in rte_kni API.
Here is our implementation:
static int
linux_set_carrier(const char *name, int status)
{
char path[64];
const char *carrier = status ? "1" : "0";
int fd, ret;
sprintf(path, "/sys/devices/virtual/net/%s/carrier", name);
fd = open(path, O_WRONLY);
if (fd == -1) {
return -errno;
}
ret = write(fd, carrier, 2);
if (ret == -1) {
close(fd);
return -errno;
}
close(fd);
return 0;
}
Best regards,
Igor
On Thu, Aug 30, 2018 at 2:10 AM, Stephen Hemminger <
stephen@networkplumber.org> wrote:
> On Wed, 29 Aug 2018 19:41:23 -0300
> Dan Gora <dg@adax.com> wrote:
>
> > On Wed, Aug 29, 2018 at 7:12 PM, Dan Gora <dg@adax.com> wrote:
> > > On Wed, Aug 29, 2018 at 7:00 PM, Stephen Hemminger
> > > <stephen@networkplumber.org> wrote:
> > >>> >> Add a new API function to KNI, rte_kni_update_link() to allow DPDK
> > >>> >> applications to update the link state for the KNI network
> interfaces
> > >>> >> in the linux kernel.
> > >>> >>
> > >>> >> Note that the default carrier state is set to off when the
> interface
> > >>> >> is opened.
> > >>> >>
> > >>> >> Signed-off-by: Dan Gora <dg@adax.com>
> > >>> >
> > >>> > Do you really need a special ioctl for this?
> > >>> > There is already ability to set link state via sysfs or netlink.
> > >>>
> > >>> I think yes.. AFAIK sysfs does not constitute a stable API;
> > >>
> > >> It is a stable API on Linux.
> > >
> >
> > Actually this does not seem to be completely true...
> >
> > From Documentation/admin-guide/sysfs-rules.rst:
> >
> > Rules on how to access information in sysfs
> > ===========================================
> >
> > The kernel-exported sysfs exports internal kernel implementation details
> > and depends on internal kernel structures and layout. It is agreed upon
> > by the kernel developers that the Linux kernel does not provide a stable
> > internal API. Therefore, there are aspects of the sysfs interface that
> > may not be stable across kernel releases.
> >
> > <snip>
> >
> > - devices are only "devices"
> > There is no such thing like class-, bus-, physical devices,
> > interfaces, and such that you can rely on in userspace. Everything is
> > just simply a "device". Class-, bus-, physical, ... types are just
> > kernel implementation details which should not be expected by
> > applications that look for devices in sysfs.
> >
> > The properties of a device are:
> >
> > - devpath (``/devices/pci0000:00/0000:00:1d.1/usb2/2-2/2-2:1.0``)
> > <snip>
> >
> > - kernel name (``sda``, ``tty``, ``0000:00:1f.2``, ...)
> > <snip>
> >
> > - subsystem (``block``, ``tty``, ``pci``, ...)
> > <snip>
> >
> > - driver (``tg3``, ``ata_piix``, ``uhci_hcd``)
> > <snip>
> >
> > - attributes
> > <snip>
> >
> > Everything else is just a kernel driver-core implementation detail
> > that should not be assumed to be stable across kernel releases.
>
> Network device sysfs is stable. No one ever got around to putting it in
> documentation
> I wouldn't worry, once anything in /sys/class/net is added it is not going
> to change without major breakage in many many tools.
>
next prev parent reply other threads:[~2018-08-30 9:49 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-28 22:45 [dpdk-dev] [PATCH 00/10] kni: Interface detach and link status fixes Dan Gora
2018-06-29 1:54 ` Dan Gora
2018-06-29 1:54 ` [dpdk-dev] [PATCH v2 01/10] kni: remove unused variables from struct kni_dev Dan Gora
2018-08-29 10:29 ` Ferruh Yigit
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 02/10] kni: separate releasing netdev from freeing KNI interface Dan Gora
2018-08-29 10:59 ` Ferruh Yigit
2018-09-04 0:20 ` Dan Gora
2018-09-04 0:36 ` Dan Gora
2018-10-10 17:24 ` Ferruh Yigit
2018-10-10 18:18 ` Dan Gora
2018-10-10 22:51 ` Ferruh Yigit
2018-10-10 23:38 ` Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 03/10] kni: don't touch struct kni_dev after freeing Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 04/10] kni: add rte_kni_free to KNI library Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 05/10] kni: don't run rte_kni_handle_request after interface release Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 06/10] kni: increase length of timeout for KNI responses Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 07/10] kni: update kni test for rte_kni_free Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 08/10] kni: add rte_kni_free to KNI example app Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 09/10] kni: add rte_kni_free to KNI vdev driver Dan Gora
2018-06-29 1:55 ` [dpdk-dev] [PATCH v2 10/10] kni: add API to set link status on kernel interface Dan Gora
2018-08-29 11:48 ` Ferruh Yigit
2018-08-29 21:10 ` Dan Gora
2018-08-29 22:01 ` Stephen Hemminger
2018-08-29 15:54 ` Stephen Hemminger
2018-08-29 21:02 ` Dan Gora
2018-08-29 22:00 ` Stephen Hemminger
2018-08-29 22:12 ` Dan Gora
2018-08-29 22:41 ` Dan Gora
2018-08-29 23:10 ` Stephen Hemminger
2018-08-30 9:49 ` Igor Ryzhov [this message]
2018-08-30 10:32 ` Igor Ryzhov
2018-08-30 21:41 ` Dan Gora
2018-08-30 22:09 ` Stephen Hemminger
2018-08-30 22:11 ` Dan Gora
2018-09-04 0:47 ` Dan Gora
2018-09-05 12:57 ` Stephen Hemminger
2018-09-11 21:45 ` Dan Gora
2018-09-11 21:52 ` Stephen Hemminger
2018-09-11 22:07 ` Dan Gora
2018-09-11 23:14 ` Stephen Hemminger
2018-09-12 4:02 ` Jason Wang
2018-09-11 23:14 ` [dpdk-dev] [PATCH 0/2] " Dan Gora
2018-09-11 23:14 ` [dpdk-dev] [PATCH 1/2] " Dan Gora
2018-09-11 23:18 ` Dan Gora
2018-07-20 11:36 ` [dpdk-dev] [PATCH 00/10] kni: Interface detach and link status fixes Ferruh Yigit
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