lguest: don't set MAC address for guest unless specified

This shows up when trying to bridge:
	tap0: received packet with  own address as source address

As Max Krasnyansky points out, there's no reason to give the guest the
same mac address as the TUN device.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Max Krasnyansky <maxk@qualcomm.com>

diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index b88b0ea..6554148 100644 (file)
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -1447,21 +1447,6 @@ static void configure_device(int fd, const char *tapif, u32 ipaddr)
                err(1, "Bringing interface %s up", tapif);
 }
 
-static void get_mac(int fd, const char *tapif, unsigned char hwaddr[6])
-{
-       struct ifreq ifr;
-
-       memset(&ifr, 0, sizeof(ifr));
-       strcpy(ifr.ifr_name, tapif);
-
-       /* SIOC stands for Socket I/O Control.  G means Get (vs S for Set
-        * above).  IF means Interface, and HWADDR is hardware address.
-        * Simple! */
-       if (ioctl(fd, SIOCGIFHWADDR, &ifr) != 0)
-               err(1, "getting hw address for %s", tapif);
-       memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, 6);
-}
-
 static int get_tun_device(char tapif[IFNAMSIZ])
 {
        struct ifreq ifr;
@@ -1531,11 +1516,8 @@ static void setup_tun_net(char *arg)
        p = strchr(arg, ':');
        if (p) {
                str2mac(p+1, conf.mac);
+               add_feature(dev, VIRTIO_NET_F_MAC);
                *p = '\0';
-       } else {
-               p = arg + strlen(arg);
-               /* None supplied; query the randomly assigned mac. */
-               get_mac(ipfd, tapif, conf.mac);
        }
 
        /* arg is now either an IP address or a bridge name */
@@ -1547,13 +1529,10 @@ static void setup_tun_net(char *arg)
        /* Set up the tun device. */
        configure_device(ipfd, tapif, ip);
 
-       /* Tell Guest what MAC address to use. */
-       add_feature(dev, VIRTIO_NET_F_MAC);
        add_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY);
        /* Expect Guest to handle everything except UFO */
        add_feature(dev, VIRTIO_NET_F_CSUM);
        add_feature(dev, VIRTIO_NET_F_GUEST_CSUM);
-       add_feature(dev, VIRTIO_NET_F_MAC);
        add_feature(dev, VIRTIO_NET_F_GUEST_TSO4);
        add_feature(dev, VIRTIO_NET_F_GUEST_TSO6);
        add_feature(dev, VIRTIO_NET_F_GUEST_ECN);