sys/netinet6: Fix ABI breakage introduced with RFC 7217 support

commit 31ec8b6407fdd5a87d70265762457c67ce618283 added a `dad_failures`
variable to `struct nd_ifinfo`, which broke the netowrking ABI.

This commit fixes it by moving such variable to `struct in6_ifextra`
which is not a public interface, while `struct nd_ifinfo` is back
in its original state.

Thanks to kib, markj and glebious for their help and suggestions
in solving this problem.

Reported by:	"Herbert J. Skuhra" <herbert@gojira.at>
Tested by:	"Herbert J. Skuhra" <herbert@gojira.at>
Approved by:	glebius
Fixes:		31ec8b6407fdd5a87d70265762457c67ce618283

7 files changed, 10 insertions, 10 deletions

diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index 4f756a75fac7..8ef755e2dc0a 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -2604,6 +2604,8 @@ in6_domifattach(struct ifnet *ifp)
 	COUNTER_ARRAY_ALLOC(ext->icmp6_ifstat,
 	    sizeof(struct icmp6_ifstat) / sizeof(uint64_t), M_WAITOK);
 
+	ext->dad_failures = counter_u64_alloc(M_WAITOK);
+
 	ext->nd_ifinfo = nd6_ifattach(ifp);
 	ext->scope6_id = scope6_ifattach(ifp);
 	ext->lltable = in6_lltattach(ifp);
@@ -2639,6 +2641,7 @@ in6_domifdetach(struct ifnet *ifp, void *aux)
 	COUNTER_ARRAY_FREE(ext->icmp6_ifstat,
 	    sizeof(struct icmp6_ifstat) / sizeof(uint64_t));
 	free(ext->icmp6_ifstat, M_IFADDR);
+	counter_u64_free(ext->dad_failures);
 	free(ext, M_IFADDR);
 }
 
diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index 57fe12a1c93b..4fde346fb691 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -377,7 +377,7 @@ in6_get_stableifid(struct ifnet *ifp, struct in6_addr *in6, int prefixlen)
 	}
 	hostuuid_len = strlen(hostuuid);
 
-	dad_failures = counter_u64_fetch(ND_IFINFO(ifp)->dad_failures);
+	dad_failures = counter_u64_fetch(DAD_FAILURES(ifp));
 
 	/*
 	 * RFC 7217 section 7
diff --git a/sys/netinet6/in6_var.h b/sys/netinet6/in6_var.h
index e5ab83e6a2a1..e511ead24f08 100644
--- a/sys/netinet6/in6_var.h
+++ b/sys/netinet6/in6_var.h
@@ -106,9 +106,11 @@ struct in6_ifextra {
 	struct scope6_id *scope6_id;
 	struct lltable *lltable;
 	struct mld_ifsoftc *mld_ifinfo;
+	counter_u64_t dad_failures;	/* DAD failures when using RFC 7217 stable addresses */
 };
 
 #define	LLTABLE6(ifp)	(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->lltable)
+#define	DAD_FAILURES(ifp)	(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->dad_failures)
 
 #ifdef _KERNEL
 
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 938d411711f0..00df5efcef92 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -329,8 +329,6 @@ nd6_ifattach(struct ifnet *ifp)
 		nd->flags |= ND6_IFF_STABLEADDR;
 	}
 
-	nd->dad_failures = counter_u64_alloc(M_WAITOK);
-
 	return nd;
 }
 
@@ -350,8 +348,6 @@ nd6_ifdetach(struct ifnet *ifp, struct nd_ifinfo *nd)
 	}
 	NET_EPOCH_EXIT(et);
 
-	counter_u64_free(nd->dad_failures);
-
 	free(nd, M_IP6NDP);
 }
 
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index 1de2a77ddf6d..5fe027ac5e7c 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -76,7 +76,6 @@ struct nd_ifinfo {
 	u_int8_t randomseed0[8]; /* upper 64 bits of MD5 digest */
 	u_int8_t randomseed1[8]; /* lower 64 bits (usually the EUI64 IFID) */
 	u_int8_t randomid[8];	/* current random ID */
-	counter_u64_t dad_failures;	/* DAD failures when using RFC 7217 stable addresses */
 };
 
 #define ND6_IFF_PERFORMNUD	0x1
diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
index 76b1fd86ee08..cc17b4e1a402 100644
--- a/sys/netinet6/nd6_nbr.c
+++ b/sys/netinet6/nd6_nbr.c
@@ -1473,7 +1473,7 @@ nd6_dad_timer(void *arg)
 			if ((ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) == 0) {
 				ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
 				if ((ND_IFINFO(ifp)->flags & ND6_IFF_STABLEADDR) && !(ia->ia6_flags & IN6_IFF_TEMPORARY))
-					counter_u64_zero(ND_IFINFO(ifp)->dad_failures);
+					counter_u64_zero(DAD_FAILURES(ifp));
 			}
 
 			nd6log((LOG_DEBUG,
@@ -1522,10 +1522,10 @@ nd6_dad_duplicated(struct ifaddr *ifa, struct dadq *dp)
 	 * More addresses will be generated as long as retries are not exhausted.
 	 */
 	if ((ND_IFINFO(ifp)->flags & ND6_IFF_STABLEADDR) && !(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
-		uint64_t dad_failures = counter_u64_fetch(ND_IFINFO(ifp)->dad_failures);
+		uint64_t dad_failures = counter_u64_fetch(DAD_FAILURES(ifp));
 
 		if (dad_failures <= V_ip6_stableaddr_maxretries) {
-			counter_u64_add(ND_IFINFO(ifp)->dad_failures, 1);
+			counter_u64_add(DAD_FAILURES(ifp), 1);
 			/* if retries exhausted, output an informative error message */
 			if (dad_failures == V_ip6_stableaddr_maxretries)
 				log(LOG_ERR, "%s: manual intervention required, consider disabling \"stableaddr\" on the interface"
diff --git a/sys/netinet6/nd6_rtr.c b/sys/netinet6/nd6_rtr.c
index 01623a4506be..78dc55dd292f 100644
--- a/sys/netinet6/nd6_rtr.c
+++ b/sys/netinet6/nd6_rtr.c
@@ -1757,7 +1757,7 @@ prelist_update(struct nd_prefixctl *new, struct nd_defrouter *dr,
 		 * to fail and no further retries should happen.
 		 */
 		if (ND_IFINFO(ifp)->flags & ND6_IFF_STABLEADDR &&
-		    counter_u64_fetch(ND_IFINFO(ifp)->dad_failures) <= V_ip6_stableaddr_maxretries &&
+		    counter_u64_fetch(DAD_FAILURES(ifp)) <= V_ip6_stableaddr_maxretries &&
 		    ifa6->ia6_flags & (IN6_IFF_DUPLICATED | IN6_IFF_TEMPORARY))
 			continue;