[PATCH] aoe: improve allowed interfaces configuration

  "cat /dev/etherd/err" blocks, waiting for error diagnostic output,

  like any retransmitted packets.

  The /dev/etherd/interfaces special file is obsoleted by the

  aoe_iflist boot option and module option (and its sysfs entry

  described in the next section).

  "echo eth2 eth4 > /dev/etherd/interfaces" tells the aoe driver to

  limit ATA over Ethernet traffic to eth2 and eth4.  AoE traffic from

  untrusted networks should be ignored as a matter of security.

      e4.7            eth1              up

      e4.8            eth1              up

      e4.9            eth1              up

  Use /sys/module/aoe/parameters/aoe_iflist (or better, the driver

  option discussed below) instead of /dev/etherd/interfaces to limit

  AoE traffic to the network interfaces in the given

  whitespace-separated list.  Unlike the old character device, the

  sysfs entry can be read from as well as written to.

  It's helpful to trigger discovery after setting the list of allowed

  interfaces.  If your distro provides an aoe-discover script, you can

  use that.  Otherwise, you can directly use the /dev/etherd/discover

  file described above.

DRIVER OPTIONS

  There is a boot option for the built-in aoe driver and a

  corresponding module parameter, aoe_iflist.  Without this option,

  all network interfaces may be used for ATA over Ethernet.  Here is a

  usage example for the module parameter.

    modprobe aoe_iflist="eth1 eth3"

#include <linux/hdreg.h>

#include <linux/blkdev.h>

#include <linux/netdevice.h>

#include <linux/moduleparam.h>

#include "aoe.h"

#define NECODES 5

};

static char aoe_iflist[IFLISTSZ];

module_param_string(aoe_iflist, aoe_iflist, IFLISTSZ, 0600);

MODULE_PARM_DESC(aoe_iflist, "aoe_iflist=\"dev1 [dev2 ...]\"\n");

#ifndef MODULE

static int __init aoe_iflist_setup(char *str)

{

	strncpy(aoe_iflist, str, IFLISTSZ);

	aoe_iflist[IFLISTSZ - 1] = '\0';

	return 1;

}

__setup("aoe_iflist=", aoe_iflist_setup);

#endif

int

is_aoe_netif(struct net_device *ifp)

	if (aoe_iflist[0] == '\0')

		return 1;

	for (p = aoe_iflist; *p; p = q + strspn(q, WHITESPACE)) {

	p = aoe_iflist + strspn(aoe_iflist, WHITESPACE);

	for (; *p; p = q + strspn(q, WHITESPACE)) {

		q = p + strcspn(p, WHITESPACE);

		if (q != p)

			len = q - p;