git: cf275806b6ed - main - nd6: Fix delayed NA for proxy addresses
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Date: Thu, 02 Apr 2026 11:11:49 UTC
The branch main has been updated by pouria:
URL: https://cgit.FreeBSD.org/src/commit/?id=cf275806b6eddd66a3d82be56b3672dc5afab525
commit cf275806b6eddd66a3d82be56b3672dc5afab525
Author: Pouria Mousavizadeh Tehrani <pouria@FreeBSD.org>
AuthorDate: 2026-03-13 14:25:01 +0000
Commit: Pouria Mousavizadeh Tehrani <pouria@FreeBSD.org>
CommitDate: 2026-04-02 11:11:26 +0000
nd6: Fix delayed NA for proxy addresses
Delayed proxy addresses need special handling, since
they can use link-local ifa as their source address and
have different link-layer data in their response.
Fixes: f37fbe30f559
Reviewed by: glebius, markj
Differential Revision: https://reviews.freebsd.org/D55850
---
sys/netinet6/nd6.h | 1 +
sys/netinet6/nd6_nbr.c | 72 ++++++++++++++++++++++++++++++++++++--------------
2 files changed, 53 insertions(+), 20 deletions(-)
diff --git a/sys/netinet6/nd6.h b/sys/netinet6/nd6.h
index 70cd6dfbdb62..8c069c294593 100644
--- a/sys/netinet6/nd6.h
+++ b/sys/netinet6/nd6.h
@@ -156,6 +156,7 @@ struct in6_ndifreq {
#define ND6_QUEUE_FLAG_NEWGUA 0x01 /* new global unicast address event */
#define ND6_QUEUE_FLAG_LLADDR 0x02 /* link-layer address change event */
#define ND6_QUEUE_FLAG_ANYCAST 0x04 /* delay NA for anycast address */
+#define ND6_QUEUE_FLAG_PROXY 0x08 /* delay NA for proxy address */
/* GRAND specific flags */
#define ND6_QUEUE_GRAND_MASK (ND6_QUEUE_FLAG_NEWGUA|ND6_QUEUE_FLAG_LLADDR)
diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
index 44677a9637bd..c345e96f8d3f 100644
--- a/sys/netinet6/nd6_nbr.c
+++ b/sys/netinet6/nd6_nbr.c
@@ -98,7 +98,8 @@ static void nd6_na_output_fib(struct ifnet *, const struct in6_addr *,
const struct in6_addr *, u_long, int, struct sockaddr *, u_int);
static void nd6_ns_output_fib(struct ifnet *, const struct in6_addr *,
const struct in6_addr *, const struct in6_addr *, uint8_t *, u_int);
-static void nd6_queue_add(struct ifaddr *, struct in6_addr *, int, uint32_t);
+static void nd6_queue_add(struct ifaddr *, struct in6_addr *,
+ struct in6_addr *, struct sockaddr_dl *, int, uint32_t);
static struct ifaddr *nd6_proxy_fill_sdl(struct ifnet *,
const struct in6_addr *, struct sockaddr_dl *);
@@ -124,10 +125,12 @@ SYSCTL_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_ONLINKNSRFC4861,
struct nd_queue {
TAILQ_ENTRY(nd_queue) ndq_list;
- struct ifaddr *ndq_ifa;
- struct in6_addr ndq_daddr;
- uint32_t ndq_flags;
- struct callout ndq_callout;
+ struct ifaddr *ndq_ifa;
+ struct in6_addr ndq_daddr;
+ struct in6_addr ndq_taddr;
+ struct sockaddr_dl ndq_sdl;
+ uint32_t ndq_flags;
+ struct callout ndq_callout;
};
/*
@@ -148,7 +151,8 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
union nd_opts ndopts;
char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
char *lladdr;
- int anycast, lladdrlen, proxy, rflag, tentative, tlladdr;
+ int lladdrlen, rflag, tentative, tlladdr;
+ uint32_t dflags;
ifa = NULL;
@@ -276,10 +280,10 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
/* (2) check. */
- proxy = 0;
+ dflags = 0;
if (ifa == NULL) {
if ((ifa = nd6_proxy_fill_sdl(ifp, &taddr6, &proxydl)) != NULL)
- proxy = 1;
+ dflags |= ND6_QUEUE_FLAG_PROXY;
}
if (ifa == NULL) {
/*
@@ -289,8 +293,9 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
*/
goto freeit;
}
+ if ((((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST) != 0)
+ dflags |= ND6_QUEUE_FLAG_ANYCAST;
myaddr6 = *IFA_IN6(ifa);
- anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
goto freeit;
@@ -341,7 +346,7 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
* Link-Layer Address option is not included, the Override flag SHOULD
* be set to zero. Otherwise, the Override flag SHOULD be set to one.
*/
- if (anycast == 0 && proxy == 0 && (tlladdr & ND6_NA_OPT_LLA) != 0)
+ if (dflags == 0 && (tlladdr & ND6_NA_OPT_LLA) != 0)
rflag |= ND_NA_FLAG_OVERRIDE;
/*
* If the source address is unspecified address, entries must not
@@ -362,12 +367,11 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
* be delayed by a random time between 0 and MAX_ANYCAST_DELAY_TIME
* to reduce the probability of network congestion.
*/
- if (anycast == 0)
- nd6_na_output_fib(ifp, &saddr6, &taddr6, rflag, tlladdr,
- proxy ? (struct sockaddr *)&proxydl : NULL, M_GETFIB(m));
+ if (dflags == 0)
+ nd6_na_output_fib(ifp, &saddr6, &taddr6, rflag, tlladdr, NULL, M_GETFIB(m));
else
- nd6_queue_add(ifa, &saddr6, arc4random() %
- (MAX_ANYCAST_DELAY_TIME * hz), ND6_QUEUE_FLAG_ANYCAST);
+ nd6_queue_add(ifa, &saddr6, &taddr6, &proxydl, arc4random() %
+ (MAX_ANYCAST_DELAY_TIME * hz), dflags);
freeit:
if (ifa != NULL)
ifa_free(ifa);
@@ -1672,10 +1676,12 @@ nd6_queue_timer(void *arg)
struct nd_queue *ndq = arg;
struct ifaddr *ifa = ndq->ndq_ifa;
struct ifnet *ifp;
- struct in6_addr daddr;
+ struct in6_addr daddr, taddr;
+ struct sockaddr_dl sdl;
struct epoch_tracker et;
int delay, tlladdr;
u_long flags;
+ bool proxy;
KASSERT(ifa != NULL, ("ND6 queue entry %p with no address", ndq));
@@ -1684,6 +1690,7 @@ nd6_queue_timer(void *arg)
NET_EPOCH_ENTER(et);
daddr = ndq->ndq_daddr;
+ taddr = ndq->ndq_taddr;
tlladdr = ND6_NA_OPT_LLA;
flags = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
if ((ifp->if_inet6->nd_flags & ND6_IFF_ACCEPT_RTADV) != 0 && V_ip6_norbit_raif)
@@ -1711,6 +1718,13 @@ nd6_queue_timer(void *arg)
/* anycast advertisement delay rule (RFC 4861 7.2.7, SHOULD) */
if ((ndq->ndq_flags & ND6_QUEUE_FLAG_ANYCAST) != 0)
flags |= ND_NA_FLAG_SOLICITED;
+ /* proxy advertisement delay rule (RFC 4861 7.2.8, SHOULD) */
+ proxy = false;
+ if ((ndq->ndq_flags & ND6_QUEUE_FLAG_PROXY) != 0) {
+ flags |= ND_NA_FLAG_SOLICITED;
+ sdl = ndq->ndq_sdl;
+ proxy = true;
+ }
/*
* if it was GRAND, wait at least a RetransTimer
@@ -1724,16 +1738,23 @@ nd6_queue_timer(void *arg)
nd6_queue_rel(ndq);
if (__predict_true(in6_setscope(&daddr, ifp, NULL) == 0))
- nd6_na_output_fib(ifp, &daddr, IFA_IN6(ifa), flags, tlladdr,
- NULL, ifp->if_fib);
+ nd6_na_output_fib(ifp, &daddr, &taddr, flags, tlladdr,
+ proxy ? (struct sockaddr *)&sdl : NULL, ifp->if_fib);
NET_EPOCH_EXIT(et);
CURVNET_RESTORE();
}
+/*
+ * Queue a delayed IPv6 Neighbor Advertisement.
+ *
+ * daddr: destination address (who the NA is sent to)
+ * taddr: target address being advertised (used for proxy NAs)
+ * sdl: link-layer address (used for proxy NAs)
+ */
static void
nd6_queue_add(struct ifaddr *ifa, struct in6_addr *daddr,
- int delay, uint32_t flags)
+ struct in6_addr *taddr, struct sockaddr_dl *sdl, int delay, uint32_t flags)
{
struct nd_queue *ndq = NULL;
struct ifnet *ifp;
@@ -1775,6 +1796,17 @@ nd6_queue_add(struct ifaddr *ifa, struct in6_addr *daddr,
}
memcpy(&ndq->ndq_daddr, daddr, sizeof(struct in6_addr));
+ /*
+ * For proxy NAs, the target address (taddr) being advertised differs from
+ * the interface address (ifa), so we must explicitly store both the proxy
+ * target address and its link-layer address (sdl).
+ * For non-proxy NAs, use the interface address (ifa) itself as the target.
+ */
+ if ((flags & ND6_QUEUE_FLAG_PROXY) != 0) {
+ memcpy(&ndq->ndq_taddr, taddr, sizeof(struct in6_addr));
+ memcpy(&ndq->ndq_sdl, sdl, sizeof(struct sockaddr_dl));
+ } else
+ memcpy(&ndq->ndq_taddr, IFA_IN6(ifa), sizeof(struct in6_addr));
ndq->ndq_flags = flags;
nd6log((LOG_DEBUG, "%s: delay IPv6 NA for %s\n", if_name(ifp),
@@ -1842,7 +1874,7 @@ nd6_grand_start(struct ifaddr *ifa, uint32_t flags)
daddr = in6addr_linklocal_allnodes;
delay = ext->nd_retrans * hz / 1000;
- nd6_queue_add(ifa, &daddr, count * delay, flags);
+ nd6_queue_add(ifa, &daddr, NULL, NULL, count * delay, flags);
}
/*