[dpdk-dev] [PATCH v3 6/8] net/vdev_netvsc: skip routed netvsc probing

[Matan Azrad]

Hi Stephan

From: Stephen Hemminger, Tuesday, January 9, 2018 8:51 PM
> To: Matan Azrad <matan at mellanox.com>
> Cc: Ferruh Yigit <ferruh.yigit at intel.com>; Thomas Monjalon
> <thomas at monjalon.net>; dev at dpdk.org; Raslan Darawsheh
> <rasland at mellanox.com>
> Subject: Re: [PATCH v3 6/8] net/vdev_netvsc: skip routed netvsc probing
> 
> On Tue,  9 Jan 2018 14:47:31 +0000
> Matan Azrad <matan at mellanox.com> wrote:
> 
> > NetVSC netdevices which are already routed should not be probed
> > because they are used for management purposes by the HyperV.
> >
> > prevent routed netvsc devices probing.
> >
> > Signed-off-by: Raslan Darawsheh <rasland at mellanox.com>
> > Signed-off-by: Matan Azrad <matan at mellanox.com>
> > ---
> >  doc/guides/nics/vdev_netvsc.rst       |  2 +-
> >  drivers/net/vdev_netvsc/vdev_netvsc.c | 46
> > +++++++++++++++++++++++++++++++++++
> >  2 files changed, 47 insertions(+), 1 deletion(-)
> >
> > diff --git a/doc/guides/nics/vdev_netvsc.rst
> > b/doc/guides/nics/vdev_netvsc.rst index fde1fb8..f779862 100644
> > --- a/doc/guides/nics/vdev_netvsc.rst
> > +++ b/doc/guides/nics/vdev_netvsc.rst
> > @@ -87,4 +87,4 @@ The following device parameters are supported:
> >    MAC address.
> >
> >  Not specifying either ``iface`` or ``mac`` makes this driver attach
> > itself to -all NetVSC interfaces found on the system.
> > +all unrouted NetVSC interfaces found on the system.
> > diff --git a/drivers/net/vdev_netvsc/vdev_netvsc.c
> > b/drivers/net/vdev_netvsc/vdev_netvsc.c
> > index 3d8895b..4295b92 100644
> > --- a/drivers/net/vdev_netvsc/vdev_netvsc.c
> > +++ b/drivers/net/vdev_netvsc/vdev_netvsc.c
> > @@ -38,6 +38,7 @@
> >  #define VDEV_NETVSC_PROBE_MS 1000
> >
> >  #define NETVSC_CLASS_ID "{f8615163-df3e-46c5-913f-f2d2f965ed0e}"
> > +#define NETVSC_MAX_ROUTE_LINE_SIZE 300
> >
> >  #define DRV_LOG(level, ...) \
> >  	rte_log(RTE_LOG_ ## level, \
> > @@ -192,6 +193,44 @@ static LIST_HEAD(, vdev_netvsc_ctx)
> > vdev_netvsc_ctx_list =  }
> >
> >  /**
> > + * Determine if a network interface has a route.
> > + *
> > + * @param[in] name
> > + *   Network device name.
> > + *
> > + * @return
> > + *   A nonzero value when interface has an route. In case of error,
> > + *   rte_errno is updated and 0 returned.
> > + */
> > +static int
> > +vdev_netvsc_has_route(const char *name) {
> > +	FILE *fp;
> > +	int ret = 0;
> > +	char route[NETVSC_MAX_ROUTE_LINE_SIZE];
> > +	char *netdev;
> > +
> > +	fp = fopen("/proc/net/route", "r");
> > +	if (!fp) {
> > +		rte_errno = errno;
> > +		return 0;
> > +	}
> > +	while (fgets(route, NETVSC_MAX_ROUTE_LINE_SIZE, fp) != NULL) {
> > +		netdev = strtok(route, "\t");
> > +		if (strcmp(netdev, name) == 0) {
> > +			ret = 1;
> > +			break;
> > +		}
> > +		/* Move file pointer to the next line. */
> > +		while (strchr(route, '\n') == NULL &&
> > +		       fgets(route, NETVSC_MAX_ROUTE_LINE_SIZE, fp) !=
> NULL)
> > +			;
> > +	}
> > +	fclose(fp);
> > +	return ret;
> > +}
> 
> In many ways /proc/net/route is legacy intervace.
> And system may have 1 M routes.
> 
> Maybe there is faster way to do this with netlink by looking to see if there is
> an address associated with the interface.

Actually this is control path, we don't care about performance very much.
But I can get other idea here, Do you have suggestion?

Thanks!