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Put the bridge mac inheritance behind a sysctl with the default off as this

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still needs all the edge cases fixed.

Submitted by:	Eygene Ryabinkin
This commit is contained in:
Andrew Thompson 2008-09-08 03:28:26 +00:00
parent a2a72fd640
commit 6945d73b44
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=182862
2 changed files with 23 additions and 2 deletions
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16
share/man/man4/if_bridge.4
View File

@ -92,6 +92,22 @@ the same link addresses.
The address can be changed by assigning the desired link address using
.Xr ifconfig 8 .
.Pp
If
.Xr sysctl 8
node
.Va net.link.bridge.inherit_mac
has non-zero value, newly created bridge will inherit MAC address
from its first member instead of choosing random link-level address.
This will provide more predictable bridge MAC without any
additional configuration, but currently this feature is known
to break some L2 protocols, for example PPPoE that is provided
by
.Xr ng_pppoe 4
and
.Xr ppp 8 .
Now this feature is considered as experimental and is turned off
by-default.
.Pp
A bridge can be used to provide several services, such as a simple
802.11-to-Ethernet bridge for wireless hosts, and traffic isolation.
.Pp

9
sys/net/if_bridge.c
View File

@ -347,6 +347,7 @@ static int pfil_ipfw_arp = 0; /* layer2 filter with ipfw */
static int pfil_local_phys = 0; /* run pfil hooks on the physical interface for
locally destined packets */
static int log_stp = 0; /* log STP state changes */
static int bridge_inherit_mac = 0; /* share MAC with first bridge member */
SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_onlyip, CTLFLAG_RW,
&pfil_onlyip, 0, "Only pass IP packets when pfil is enabled");
SYSCTL_INT(_net_link_bridge, OID_AUTO, ipfw_arp, CTLFLAG_RW,
@ -360,6 +361,9 @@ SYSCTL_INT(_net_link_bridge, OID_AUTO, pfil_local_phys, CTLFLAG_RW,
"Packet filter on the physical interface for locally destined packets");
SYSCTL_INT(_net_link_bridge, OID_AUTO, log_stp, CTLFLAG_RW,
&log_stp, 0, "Log STP state changes");
SYSCTL_INT(_net_link_bridge, OID_AUTO, inherit_mac, CTLFLAG_RW,
&bridge_inherit_mac, 0,
"Inherit MAC address from the first bridge member");
struct bridge_control {
int (*bc_func)(struct bridge_softc *, void *);
@ -923,7 +927,8 @@ bridge_delete_member(struct bridge_softc *sc, struct bridge_iflist *bif,
* the mac address of the bridge to the address of the next member, or
* to its default address if no members are left.
*/
if (!memcmp(IF_LLADDR(sc->sc_ifp), IF_LLADDR(ifs), ETHER_ADDR_LEN)) {
if (bridge_inherit_mac &&
!memcmp(IF_LLADDR(sc->sc_ifp), IF_LLADDR(ifs), ETHER_ADDR_LEN)) {
if (LIST_EMPTY(&sc->sc_iflist))
bcopy(sc->sc_defaddr,
IF_LLADDR(sc->sc_ifp), ETHER_ADDR_LEN);
@ -1030,7 +1035,7 @@ bridge_ioctl_add(struct bridge_softc *sc, void *arg)
* member and the MAC address of the bridge has not been changed from
* the default randomly generated one.
*/
if (LIST_EMPTY(&sc->sc_iflist) &&
if (bridge_inherit_mac && LIST_EMPTY(&sc->sc_iflist) &&
!memcmp(IF_LLADDR(sc->sc_ifp), sc->sc_defaddr, ETHER_ADDR_LEN))
bcopy(IF_LLADDR(ifs), IF_LLADDR(sc->sc_ifp), ETHER_ADDR_LEN);