Currently if you try to configure the same IPv6 address twice via the
SIOCAIFADDR_IN6 ioctl(2) the kernel will return EEXIST and the address
will be unset:
# ifconfig vether0 inet6 2001::1
# ifconfig vether0 inet6 2001::1
ifconfig: SIOCAIFADDR: File exists
Diff below fixes that by not inserting the local route if we're "just"
updating an existing address. sebastia@ confirmed it fixes his use
case, so I'm looking for oks.
Index: netinet6/in6.c
===================================================================
RCS file: /cvs/src/sys/netinet6/in6.c,v
retrieving revision 1.181
diff -u -p -r1.181 in6.c
--- netinet6/in6.c 3 Dec 2015 13:13:42 -0000 1.181
+++ netinet6/in6.c 18 Dec 2015 09:27:18 -0000
@@ -444,7 +444,7 @@ in6_control(struct socket *so, u_long cm
case SIOCAIFADDR_IN6:
{
- int plen, error = 0;
+ int plen, error = 0, newifaddr = 0;
/* reject read-only flags */
if ((ifra->ifra_flags & IN6_IFF_DUPLICATED) != 0 ||
@@ -454,12 +454,15 @@ in6_control(struct socket *so, u_long cm
return (EINVAL);
}
+ if (ia6 == NULL)
+ newifaddr = 1;
+
/*
* Make the address tentative before joining multicast
* addresses, so that corresponding MLD responses would
* not have a tentative source address.
*/
- if ((ia6 == NULL) && in6if_do_dad(ifp))
+ if (newifaddr && in6if_do_dad(ifp))
ifra->ifra_flags |= IN6_IFF_TENTATIVE;
/*
@@ -477,8 +480,9 @@ in6_control(struct socket *so, u_long cm
splx(s);
if (error != 0)
return (error);
- if ((ia6 = in6ifa_ifpwithaddr(ifp, &ifra->ifra_addr.sin6_addr))
- == NULL) {
+
+ ia6 = in6ifa_ifpwithaddr(ifp, &ifra->ifra_addr.sin6_addr);
+ if (ia6 == NULL) {
/*
* this can happen when the user specify the 0 valid
* lifetime.
@@ -489,6 +493,9 @@ in6_control(struct socket *so, u_long cm
/* Perform DAD, if needed. */
if (ia6->ia6_flags & IN6_IFF_TENTATIVE)
nd6_dad_start(&ia6->ia_ifa);
+
+ if (!newifaddr)
+ break;
plen = in6_mask2len(&ia6->ia_prefixmask.sin6_addr, NULL);
if ((ifp->if_flags & IFF_LOOPBACK) || plen == 128) {
