Date: Mon, 29 Aug 2011 22:59:23 GMT From: "Matthew N. Dodd" <mdodd@FreeBSD.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/160300: bridge(4) should attempt to use a static MAC address. Message-ID: <201108292259.p7TMxN0n046541@freefall.freebsd.org> Resent-Message-ID: <201108292300.p7TN0KYX046685@freefall.freebsd.org>
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>Number: 160300
>Category: kern
>Synopsis: bridge(4) should attempt to use a static MAC address.
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Mon Aug 29 23:00:19 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:
>Release:
>Organization:
>Environment:
System: FreeBSD neo-sasami.jurai.net 8.2-STABLE FreeBSD 8.2-STABLE #5 r224868M: Mon Aug 15 21:36:11 EDT 2011 root@neo-sasami.jurai.net:/vol/raid/svn/stable8/sys/i386/compile/DL380G3 i386
Description:
bridge(4) uses a random number function to generate it's MAC
address. This causes issues with IPv6.
<precise description of the problem (multiple lines)>
>Description:
Submitter-Id: current-users
Originator: Matthew N. Dodd
Release: FreeBSD 8.2-STABLE i386
>How-To-Repeat:
>Fix:
Use the Hostid and interface unit number to generate a
MAC address and fall-back to the random number generator
on conflict.
Index: if_bridge.c
===================================================================
--- if_bridge.c (revision 224868)
+++ if_bridge.c (working copy)
@@ -85,6 +85,7 @@
#include <sys/malloc.h>
#include <sys/protosw.h>
#include <sys/systm.h>
+#include <sys/jail.h>
#include <sys/time.h>
#include <sys/socket.h> /* for net/if.h */
#include <sys/sockio.h>
@@ -560,7 +561,7 @@
{
struct bridge_softc *sc, *sc2;
struct ifnet *bifp, *ifp;
- int retry;
+ int fb, retry;
sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
@@ -600,10 +601,24 @@
* possible that we might have address collisions, so make sure that
* this hardware address isn't already in use on another bridge.
*/
+ fb = 0;
for (retry = 1; retry != 0;) {
- arc4rand(sc->sc_defaddr, ETHER_ADDR_LEN, 1);
- sc->sc_defaddr[0] &= ~1; /* clear multicast bit */
- sc->sc_defaddr[0] |= 2; /* set the LAA bit */
+ if (fb) {
+ arc4rand(sc->sc_defaddr, ETHER_ADDR_LEN, 1);
+ sc->sc_defaddr[0] &= ~1;/* clear multicast bit */
+ sc->sc_defaddr[0] |= 2; /* set the LAA bit */
+ } else {
+ unsigned long hostid;
+ getcredhostid(curthread->td_ucred, &hostid);
+ sc->sc_defaddr[0] = 0x2;
+ sc->sc_defaddr[1] = (hostid >> 24) & 0xff;
+ sc->sc_defaddr[2] = (hostid >> 16) & 0xff;
+ sc->sc_defaddr[3] = (hostid >> 8 ) & 0xff;
+ sc->sc_defaddr[4] = hostid & 0xff;
+ sc->sc_defaddr[5] = ifp->if_dunit & 0xff;
+ }
+
+ fb = 1;
retry = 0;
mtx_lock(&bridge_list_mtx);
LIST_FOREACH(sc2, &bridge_list, sc_list) {
>Release-Note:
>Audit-Trail:
>Unformatted:
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