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On the first loop for generating a bridge MAC address use the local

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hostid, this gives a good chance of keeping the same address over
reboots. This is intended to help IPV6 and similar which generate
their addresses from the mac.

PR:		kern/160300
Submitted by:	mdodd
Approved by:	re (kib)
This commit is contained in:
Andrew Thompson 2011-09-04 22:06:32 +00:00
parent 9f39e22e6d
commit 0fe082e7d5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=225380
1 changed files with 21 additions and 6 deletions
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27
sys/net/if_bridge.c
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@ -85,6 +85,7 @@ __FBSDID("$FreeBSD$");
#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 +561,8 @@ bridge_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
struct bridge_softc *sc, *sc2;
struct ifnet *bifp, *ifp;
int retry;
int fb, retry;
unsigned long hostid;
sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
ifp = sc->sc_ifp = if_alloc(IFT_ETHER);
@ -593,17 +595,30 @@ bridge_clone_create(struct if_clone *ifc, int unit, caddr_t params)
IFQ_SET_READY(&ifp->if_snd);
/*
* Generate a random ethernet address with a locally administered
* address.
* Generate an ethernet address with a locally administered address.
*
* Since we are using random ethernet addresses for the bridge, it is
* possible that we might have address collisions, so make sure that
* this hardware address isn't already in use on another bridge.
* The first try uses the hostid and falls back to arc4rand().
*/
fb = 0;
getcredhostid(curthread->td_ucred, &hostid);
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 || hostid == 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 */
} else {
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) {