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 <ohartm...@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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