git: f9e0752e3573 - main - Create new in6_purgeifaddr() which purges bound ifa prefix if it gets unused.

[Alexander V. Chernikov]

The branch main has been updated by melifaro:

URL: https://cgit.FreeBSD.org/src/commit/?id=f9e0752e3573e0b60e578e58ee2eac3d42ff533a

commit f9e0752e3573e0b60e578e58ee2eac3d42ff533a
Author:     Alexander V. Chernikov <melifaro at FreeBSD.org>
AuthorDate: 2021-01-13 00:18:00 +0000
Commit:     Alexander V. Chernikov <melifaro at FreeBSD.org>
CommitDate: 2021-01-17 20:32:25 +0000

    Create new in6_purgeifaddr() which purges bound ifa prefix if
     it gets unused.
    
    Currently if_purgeifaddrs() uses in6_purgeaddr() to remove IPv6
     ifaddrs. in6_purgeaddr() does not trrigger prefix removal if
     number of linked ifas goes to 0, as this is a low-level function.
     As a result, if_purgeifaddrs() purges all IPv4/IPv6 addresses but
     keeps corresponding IPv6 prefixes.
    
    Fix this by creating higher-level wrapper which handles unused
     prefix usecase and use it in if_purgeifaddrs().
    
    Differential revision:  https://reviews.freebsd.org/D28128
---
 sys/net/if.c           |  2 +-
 sys/netinet6/in6.c     | 53 +++++++++++++++++++++++++++++---------------------
 sys/netinet6/in6_var.h |  1 +
 3 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index 68ed4cf65dc1..74fdd066fd2d 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1077,7 +1077,7 @@ if_purgeaddrs(struct ifnet *ifp)
 #endif /* INET */
 #ifdef INET6
 		if (ifa->ifa_addr->sa_family == AF_INET6) {
-			in6_purgeaddr(ifa);
+			in6_purgeifaddr((struct in6_ifaddr *)ifa);
 			/* ifp_addrhead is already updated */
 			continue;
 		}
diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index b42cc16cdb6f..48fa8dd2efc6 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -696,31 +696,10 @@ aifaddr_out:
 	}
 
 	case SIOCDIFADDR_IN6:
-	{
-		struct nd_prefix *pr;
-
-		/*
-		 * If the address being deleted is the only one that owns
-		 * the corresponding prefix, expire the prefix as well.
-		 * XXX: theoretically, we don't have to worry about such
-		 * relationship, since we separate the address management
-		 * and the prefix management.  We do this, however, to provide
-		 * as much backward compatibility as possible in terms of
-		 * the ioctl operation.
-		 * Note that in6_purgeaddr() will decrement ndpr_addrcnt.
-		 */
-		pr = ia->ia6_ndpr;
-		in6_purgeaddr(&ia->ia_ifa);
-		if (pr != NULL && pr->ndpr_addrcnt == 0) {
-			ND6_WLOCK();
-			nd6_prefix_unlink(pr, NULL);
-			ND6_WUNLOCK();
-			nd6_prefix_del(pr);
-		}
+		in6_purgeifaddr(ia);
 		EVENTHANDLER_INVOKE(ifaddr_event_ext, ifp, &ia->ia_ifa,
 		    IFADDR_EVENT_DEL);
 		break;
-	}
 
 	default:
 		if (ifp->if_ioctl == NULL) {
@@ -1364,6 +1343,36 @@ in6_purgeaddr(struct ifaddr *ifa)
 	in6_unlink_ifa(ia, ifp);
 }
 
+/*
+ * Removes @ia from the corresponding interfaces and unlinks corresponding
+ *  prefix if no addresses are using it anymore.
+ */
+void
+in6_purgeifaddr(struct in6_ifaddr *ia)
+{
+	struct nd_prefix *pr;
+
+	/*
+	 * If the address being deleted is the only one that owns
+	 * the corresponding prefix, expire the prefix as well.
+	 * XXX: theoretically, we don't have to worry about such
+	 * relationship, since we separate the address management
+	 * and the prefix management.  We do this, however, to provide
+	 * as much backward compatibility as possible in terms of
+	 * the ioctl operation.
+	 * Note that in6_purgeaddr() will decrement ndpr_addrcnt.
+	 */
+	pr = ia->ia6_ndpr;
+	in6_purgeaddr(&ia->ia_ifa);
+	if (pr != NULL && pr->ndpr_addrcnt == 0) {
+		ND6_WLOCK();
+		nd6_prefix_unlink(pr, NULL);
+		ND6_WUNLOCK();
+		nd6_prefix_del(pr);
+	}
+}
+
+
 static void
 in6_unlink_ifa(struct in6_ifaddr *ia, struct ifnet *ifp)
 {
diff --git a/sys/netinet6/in6_var.h b/sys/netinet6/in6_var.h
index f5e6a931ae64..5f4364c6fba0 100644
--- a/sys/netinet6/in6_var.h
+++ b/sys/netinet6/in6_var.h
@@ -887,6 +887,7 @@ int	in6_update_ifa(struct ifnet *, struct in6_aliasreq *,
 void	in6_prepare_ifra(struct in6_aliasreq *, const struct in6_addr *,
 	const struct in6_addr *);
 void	in6_purgeaddr(struct ifaddr *);
+void	in6_purgeifaddr(struct in6_ifaddr *);
 int	in6if_do_dad(struct ifnet *);
 void	in6_savemkludge(struct in6_ifaddr *);
 void	*in6_domifattach(struct ifnet *);