From: Justin Pettit <jpettit@nicira.com>
Date: Thu, 15 Nov 2012 22:27:28 +0000 (-0800)
Subject: netdev-linux: "Down" tap devices before setting hw addr.
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?p=openvswitch;a=commitdiff_plain;h=7eb1bd81120806b4189e860b2a6468925d8e7bba

netdev-linux: "Down" tap devices before setting hw addr.

On Linux, it is not possible to set the mac address on "up" tap
interfaces.  This commit temporarily "down"s the interface so the
address can be set for the netdev_linux_set_etheraddr() call.

Signed-off-by: Justin Pettit <jpettit@nicira.com>
---

diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 0460c069..b8139682 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -1028,6 +1028,7 @@ netdev_linux_set_etheraddr(struct netdev *netdev_,
     struct netdev_dev_linux *netdev_dev =
                                 netdev_dev_linux_cast(netdev_get_dev(netdev_));
     int error;
+    bool up_again = false;
 
     if (netdev_dev->cache_valid & VALID_ETHERADDR) {
         if (netdev_dev->ether_addr_error) {
@@ -1039,6 +1040,15 @@ netdev_linux_set_etheraddr(struct netdev *netdev_,
         netdev_dev->cache_valid &= ~VALID_ETHERADDR;
     }
 
+    /* Tap devices must be brought down before setting the address. */
+    if (!strcmp(netdev_get_type(netdev_), "tap")) {
+        enum netdev_flags flags;
+
+        if (!netdev_get_flags(netdev_, &flags) && (flags & NETDEV_UP)) {
+            netdev_turn_flags_off(netdev_, NETDEV_UP, false);
+            up_again = true;
+        }
+    }
     error = set_etheraddr(netdev_get_name(netdev_), mac);
     if (!error || error == ENODEV) {
         netdev_dev->ether_addr_error = error;
@@ -1048,6 +1058,10 @@ netdev_linux_set_etheraddr(struct netdev *netdev_,
         }
     }
 
+    if (up_again) {
+        netdev_turn_flags_on(netdev_, NETDEV_UP, false);
+    }
+
     return error;
 }