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Create new in6_purgeifaddr() which purges bound ifa prefix if

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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
This commit is contained in:
Alexander V. Chernikov 2021-01-13 00:18:00 +00:00
parent da8cc827ae
commit f9e0752e35
3 changed files with 33 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/net/if.c
View File

@ -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;
}

53
sys/netinet6/in6.c
View File

@ -696,31 +696,10 @@ in6_control(struct socket *so, u_long cmd, caddr_t data,
}
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)
{

1
sys/netinet6/in6_var.h
View File

@ -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 *);