Date: Mon, 23 Jul 2018 07:11:58 +0000 (UTC) From: Eugene Grosbein <eugen@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r336628 - head/sys/net Message-ID: <201807230711.w6N7BwOj095904@repo.freebsd.org>
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Author: eugen Date: Mon Jul 23 07:11:58 2018 New Revision: 336628 URL: https://svnweb.freebsd.org/changeset/base/336628 Log: epair(4): make sure we do not duplicate MAC addresses in case of reused if_index. PR: 229957 Tested by: O. Hartmann <ohartmann@walstatt.org> Approved by: avg (mentor) Modified: head/sys/net/if_epair.c Modified: head/sys/net/if_epair.c ============================================================================== --- head/sys/net/if_epair.c Mon Jul 23 06:38:48 2018 (r336627) +++ head/sys/net/if_epair.c Mon Jul 23 07:11:58 2018 (r336628) @@ -107,6 +107,7 @@ static int epair_clone_create(struct if_clone *, char static int epair_clone_destroy(struct if_clone *, struct ifnet *); static const char epairname[] = "epair"; +static unsigned int next_index = 0; /* Netisr related definitions and sysctl. */ static struct netisr_handler epair_nh = { @@ -843,12 +844,22 @@ epair_clone_create(struct if_clone *ifc, char *name, s /* * Calculate the etheraddr hashing the hostid and the - * interface index. The result would be hopefully unique + * interface index. The result would be hopefully unique. + * Note that the "a" component of an epair instance may get moved + * to a different VNET after creation. In that case its index + * will be freed and the index can get reused by new epair instance. + * Make sure we do not create same etheraddr again. */ getcredhostid(curthread->td_ucred, (unsigned long *)&hostid); if (hostid == 0) arc4rand(&hostid, sizeof(hostid), 0); - key[0] = (uint32_t)ifp->if_index; + + if (ifp->if_index > next_index) + next_index = ifp->if_index; + else + next_index++; + + key[0] = (uint32_t)next_index; key[1] = (uint32_t)(hostid & 0xffffffff); key[2] = (uint32_t)((hostid >> 32) & 0xfffffffff); hash = jenkins_hash32(key, 3, 0);
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