Hi,
In ARP we have a queue of packets that should be sent after name
resolution. In ND6 we only hold a single packet. I would like to
unify the logic. As a bonus we limit the mbufs and get MP safe
mbuf queue.
The new function if_mqoutput() has common code for ARP and ND6.
ln_saddr6 holds the source address of the requesting packet. That
seems easier than fiddling with mbuf queue in nd6_ns_output().
ok?
bluhm
Index: net/if.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/if.c,v
retrieving revision 1.685
diff -u -p -r1.685 if.c
--- net/if.c 7 Mar 2023 20:09:48 -0000 1.685
+++ net/if.c 2 Apr 2023 22:37:23 -0000
@@ -753,6 +753,27 @@ if_enqueue_ifq(struct ifnet *ifp, struct
}
void
+if_mqoutput(struct ifnet *ifp, struct mbuf_queue *mq, unsigned int *total,
+ struct sockaddr *dst, struct rtentry *rt)
+{
+ struct mbuf_list ml;
+ struct mbuf *m;
+ unsigned int len;
+
+ mq_delist(mq, &ml);
+ len = ml_len(&ml);
+ while ((m = ml_dequeue(&ml)) != NULL)
+ ifp->if_output(ifp, m, rt_key(rt), rt);
+
+ /* XXXSMP we also discard if other CPU enqueues */
+ if (mq_len(mq) > 0) {
+ /* mbuf is back in queue. Discard. */
+ atomic_sub_int(total, len + mq_purge(mq));
+ } else
+ atomic_sub_int(total, len);
+}
+
+void
if_input(struct ifnet *ifp, struct mbuf_list *ml)
{
ifiq_input(&ifp->if_rcv, ml);
Index: net/if_var.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/if_var.h,v
retrieving revision 1.122
diff -u -p -r1.122 if_var.h
--- net/if_var.h 23 Nov 2022 14:50:59 -0000 1.122
+++ net/if_var.h 2 Apr 2023 22:37:23 -0000
@@ -320,6 +320,8 @@ extern struct ifnet_head ifnetlist;
void if_start(struct ifnet *);
int if_enqueue(struct ifnet *, struct mbuf *);
int if_enqueue_ifq(struct ifnet *, struct mbuf *);
+void if_mqoutput(struct ifnet *, struct mbuf_queue *, unsigned int *,
+ struct sockaddr *, struct rtentry *);
void if_input(struct ifnet *, struct mbuf_list *);
void if_vinput(struct ifnet *, struct mbuf *);
void if_input_process(struct ifnet *, struct mbuf_list *);
Index: netinet/if_ether.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/if_ether.c,v
retrieving revision 1.258
diff -u -p -r1.258 if_ether.c
--- netinet/if_ether.c 8 Mar 2023 04:43:08 -0000 1.258
+++ netinet/if_ether.c 2 Apr 2023 22:37:23 -0000
@@ -653,10 +653,7 @@ arpcache(struct ifnet *ifp, struct ether
struct in_addr *spa = (struct in_addr *)ea->arp_spa;
char addr[INET_ADDRSTRLEN];
struct ifnet *rifp;
- struct mbuf_list ml;
- struct mbuf *m;
time_t uptime;
- unsigned int len;
int changed = 0;
KERNEL_ASSERT_LOCKED();
@@ -729,16 +726,7 @@ arpcache(struct ifnet *ifp, struct ether
la->la_asked = 0;
la->la_refreshed = 0;
- mq_delist(&la->la_mq, &ml);
- len = ml_len(&ml);
- while ((m = ml_dequeue(&ml)) != NULL)
- ifp->if_output(ifp, m, rt_key(rt), rt);
- /* XXXSMP we discard if other CPU enqueues */
- if (mq_len(&la->la_mq) > 0) {
- /* mbuf is back in queue. Discard. */
- atomic_sub_int(&la_hold_total, len + mq_purge(&la->la_mq));
- } else
- atomic_sub_int(&la_hold_total, len);
+ if_mqoutput(ifp, &la->la_mq, &la_hold_total, rt_key(rt), rt);
return (0);
}
Index: netinet6/nd6.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/nd6.c,v
retrieving revision 1.268
diff -u -p -r1.268 nd6.c
--- netinet6/nd6.c 31 Mar 2023 19:43:32 -0000 1.268
+++ netinet6/nd6.c 3 Apr 2023 09:35:39 -0000
@@ -87,6 +87,7 @@ int nd6_debug = 0;
TAILQ_HEAD(llinfo_nd6_head, llinfo_nd6) nd6_list;
struct pool nd6_pool; /* pool for llinfo_nd6 structures */
int nd6_inuse;
+int ln_hold_total; /* [a] packets currently in the nd6 queue */
void nd6_timer(void *);
void nd6_slowtimo(void *);
@@ -300,26 +301,33 @@ nd6_llinfo_timer(struct rtentry *rt)
nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000);
nd6_ns_output(ifp, NULL, &dst->sin6_addr, ln, 0);
} else {
- struct mbuf *m = ln->ln_hold;
- if (m) {
- ln->ln_hold = NULL;
+ struct mbuf_list ml;
+ struct mbuf *m;
+ unsigned int len;
+
+ mq_delist(&ln->ln_mq, &ml);
+ len = ml_len(&ml);
+ while ((m = ml_dequeue(&ml)) != NULL) {
/*
* Fake rcvif to make the ICMP error
* more helpful in diagnosing for the
* receiver.
- * XXX: should we consider
- * older rcvif?
+ * XXX: should we consider older rcvif?
*/
m->m_pkthdr.ph_ifidx = rt->rt_ifidx;
icmp6_error(m, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_ADDR, 0);
- if (ln->ln_hold == m) {
- /* m is back in ln_hold. Discard. */
- m_freem(ln->ln_hold);
- ln->ln_hold = NULL;
- }
}
+
+ /* XXXSMP we also discard if other CPU enqueues */
+ if (mq_len(&ln->ln_mq) > 0) {
+ /* mbuf is back in queue. Discard. */
+ atomic_sub_int(&ln_hold_total,
+ len + mq_purge(&ln->ln_mq));
+ } else
+ atomic_sub_int(&ln_hold_total, len);
+
nd6_free(rt);
ln = NULL;
}
@@ -613,9 +621,8 @@ nd6_invalidate(struct rtentry *rt)
struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo;
struct sockaddr_dl *sdl = satosdl(rt->rt_gateway);
- m_freem(ln->ln_hold);
+ atomic_sub_int(&ln_hold_total, mq_purge(&ln->ln_mq));
sdl->sdl_alen = 0;
- ln->ln_hold = NULL;
ln->ln_state = ND6_LLINFO_INCOMPLETE;
ln->ln_asked = 0;
}
@@ -800,6 +807,7 @@ nd6_rtrequest(struct ifnet *ifp, int req
log(LOG_DEBUG, "%s: pool get failed\n", __func__);
break;
}
+ mq_init(&ln->ln_mq, LN_HOLD_QUEUE, IPL_SOFTNET);
nd6_inuse++;
ln->ln_rt = rt;
/* this is required for "ndp" command. - shin */
@@ -921,7 +929,7 @@ nd6_rtrequest(struct ifnet *ifp, int req
rt->rt_expire = 0;
rt->rt_llinfo = NULL;
rt->rt_flags &= ~RTF_LLINFO;
- m_freem(ln->ln_hold);
+ atomic_sub_int(&ln_hold_total, mq_purge(&ln->ln_mq));
pool_put(&nd6_pool, ln);
break;
@@ -1125,21 +1133,8 @@ fail:
* meaningless.
*/
nd6_llinfo_settimer(ln, nd6_gctimer);
-
- if (ln->ln_hold) {
- struct mbuf *n = ln->ln_hold;
- ln->ln_hold = NULL;
- /*
- * we assume ifp is not a p2p here, so just
- * set the 2nd argument as the 1st one.
- */
- ifp->if_output(ifp, n, rt_key(rt), rt);
- if (ln->ln_hold == n) {
- /* n is back in ln_hold. Discard. */
- m_freem(ln->ln_hold);
- ln->ln_hold = NULL;
- }
- }
+ if_mqoutput(ifp, &ln->ln_mq, &ln_hold_total,
+ rt_key(rt), rt);
} else if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
/* probe right away */
nd6_llinfo_settimer(ln, 0);
@@ -1328,13 +1323,23 @@ nd6_resolve(struct ifnet *ifp, struct rt
/*
* There is a neighbor cache entry, but no ethernet address
- * response yet. Replace the held mbuf (if any) with this
- * latest one.
+ * response yet. Insert mbuf in hold queue if below limit.
+ * If above the limit free the queue without queuing the new packet.
*/
if (ln->ln_state == ND6_LLINFO_NOSTATE)
ln->ln_state = ND6_LLINFO_INCOMPLETE;
- m_freem(ln->ln_hold);
- ln->ln_hold = m;
+ /* source address of prompting packet is needed by nd6_ns_output() */
+ if (m->m_len >= sizeof(struct ip6_hdr)) {
+ memcpy(&ln->ln_saddr6, &mtod(m, struct ip6_hdr *)->ip6_src,
+ sizeof(ln->ln_saddr6));
+ }
+ if (atomic_inc_int_nv(&ln_hold_total) <= LN_HOLD_TOTAL) {
+ if (mq_push(&ln->ln_mq, m) != 0)
+ atomic_dec_int(&ln_hold_total);
+ } else {
+ atomic_sub_int(&ln_hold_total, mq_purge(&ln->ln_mq) + 1);
+ m_freem(m);
+ }
/*
* If there has been no NS for the neighbor after entering the
Index: netinet6/nd6.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/nd6.h,v
retrieving revision 1.95
diff -u -p -r1.95 nd6.h
--- netinet6/nd6.h 6 Jan 2023 14:35:34 -0000 1.95
+++ netinet6/nd6.h 2 Apr 2023 22:37:23 -0000
@@ -81,12 +81,17 @@ struct in6_ndireq {
struct llinfo_nd6 {
TAILQ_ENTRY(llinfo_nd6) ln_list;
struct rtentry *ln_rt;
- struct mbuf *ln_hold; /* last packet until resolved/timeout */
+ struct mbuf_queue ln_mq; /* hold packets until resolved */
+ struct in6_addr ln_saddr6; /* source of prompting packet */
long ln_asked; /* number of queries already sent for addr */
int ln_byhint; /* # of times we made it reachable by UL hint */
short ln_state; /* reachability state */
short ln_router; /* 2^0: ND6 router bit */
};
+#define LN_HOLD_QUEUE 10
+#define LN_HOLD_TOTAL 100
+
+extern int ln_hold_total;
#define ND6_LLINFO_PERMANENT(n) ((n)->ln_rt->rt_expire == 0)
Index: netinet6/nd6_nbr.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/nd6_nbr.c,v
retrieving revision 1.143
diff -u -p -r1.143 nd6_nbr.c
--- netinet6/nd6_nbr.c 31 Mar 2023 19:43:33 -0000 1.143
+++ netinet6/nd6_nbr.c 2 Apr 2023 22:37:23 -0000
@@ -451,23 +451,14 @@ nd6_ns_output(struct ifnet *ifp, const s
* - if taddr is link local saddr6 must be link local as well
* Otherwise, we perform the source address selection as usual.
*/
- struct ip6_hdr *hip6; /* hold ip6 */
- struct in6_addr *saddr6;
+ if (ln != NULL)
+ src_sa.sin6_addr = ln->ln_saddr6;
+
+ if (!IN6_IS_ADDR_LINKLOCAL(taddr6) ||
+ IN6_IS_ADDR_UNSPECIFIED(&src_sa.sin6_addr) ||
+ IN6_IS_ADDR_LINKLOCAL(&src_sa.sin6_addr) ||
+ !in6ifa_ifpwithaddr(ifp, &src_sa.sin6_addr)) {
- if (ln && ln->ln_hold) {
- hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
- if (sizeof(*hip6) <= ln->ln_hold->m_len) {
- saddr6 = &hip6->ip6_src;
- if (saddr6 && IN6_IS_ADDR_LINKLOCAL(taddr6) &&
- !IN6_IS_ADDR_LINKLOCAL(saddr6))
- saddr6 = NULL;
- } else
- saddr6 = NULL;
- } else
- saddr6 = NULL;
- if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
- src_sa.sin6_addr = *saddr6;
- else {
struct rtentry *rt;
rt = rtalloc(sin6tosa(&dst_sa), RT_RESOLVE,
@@ -832,20 +823,7 @@ nd6_na_input(struct mbuf *m, int off, in
}
rt->rt_flags &= ~RTF_REJECT;
ln->ln_asked = 0;
- if (ln->ln_hold) {
- struct mbuf *n = ln->ln_hold;
- ln->ln_hold = NULL;
- /*
- * we assume ifp is not a loopback here, so just set the 2nd
- * argument as the 1st one.
- */
- ifp->if_output(ifp, n, rt_key(rt), rt);
- if (ln->ln_hold == n) {
- /* n is back in ln_hold. Discard. */
- m_freem(ln->ln_hold);
- ln->ln_hold = NULL;
- }
- }
+ if_mqoutput(ifp, &ln->ln_mq, &ln_hold_total, rt_key(rt), rt);
freeit:
rtfree(rt);
