[src/trunk]: src/sys/netipsec Limit the number of mbufs queued for deferred k...

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e460d48c41c1
branches:  trunk
changeset: 355672:e460d48c41c1
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Wed Aug 09 08:30:54 2017 +0000

description:
Limit the number of mbufs queued for deferred key_sendup_mbuf

It's easy to be queued hundreds of mbufs on the list under heavy
network load.

diffstat:

 sys/netipsec/key.c |  24 ++++++++++++++++++------
 1 files changed, 18 insertions(+), 6 deletions(-)

diffs (91 lines):

diff -r 8ff9980df8b3 -r e460d48c41c1 sys/netipsec/key.c
--- a/sys/netipsec/key.c        Wed Aug 09 06:19:56 2017 +0000
+++ b/sys/netipsec/key.c        Wed Aug 09 08:30:54 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: key.c,v 1.221 2017/08/09 06:04:41 ozaki-r Exp $        */
+/*     $NetBSD: key.c,v 1.222 2017/08/09 08:30:54 ozaki-r Exp $        */
 /*     $FreeBSD: src/sys/netipsec/key.c,v 1.3.2.3 2004/02/14 22:23:23 bms Exp $        */
 /*     $KAME: key.c,v 1.191 2001/06/27 10:46:49 sakane Exp $   */
 
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: key.c,v 1.221 2017/08/09 06:04:41 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: key.c,v 1.222 2017/08/09 08:30:54 ozaki-r Exp $");
 
 /*
  * This code is referd to RFC 2367
@@ -735,7 +735,7 @@
 static struct mbuf *key_getprop (const struct secasindex *);
 
 static int key_acquire (const struct secasindex *, struct secpolicy *);
-static void key_acquire_sendup_mbuf_later(struct mbuf *);
+static int key_acquire_sendup_mbuf_later(struct mbuf *);
 static void key_acquire_sendup_pending_mbuf(void);
 #ifndef IPSEC_NONBLOCK_ACQUIRE
 static struct secacq *key_newacq (const struct secasindex *);
@@ -6656,8 +6656,7 @@
         *
         * So defer key_sendup_mbuf to the timer.
         */
-       key_acquire_sendup_mbuf_later(result);
-       return 0;
+       return key_acquire_sendup_mbuf_later(result);
 
  fail:
        if (result)
@@ -6666,6 +6665,8 @@
 }
 
 static struct mbuf *key_acquire_mbuf_head = NULL;
+static unsigned key_acquire_mbuf_count = 0;
+#define KEY_ACQUIRE_MBUF_MAX   10
 
 static void
 key_acquire_sendup_pending_mbuf(void)
@@ -6684,6 +6685,7 @@
                                prev->m_nextpkt = NULL;
                        if (m == key_acquire_mbuf_head)
                                key_acquire_mbuf_head = NULL;
+                       key_acquire_mbuf_count--;
                        break;
                }
                prev = m;
@@ -6694,6 +6696,7 @@
        if (m == NULL)
                return;
 
+       m->m_nextpkt = NULL;
        error = key_sendup_mbuf(NULL, m, KEY_SENDUP_REGISTERED);
        if (error != 0)
                IPSECLOG(LOG_WARNING, "key_sendup_mbuf failed (error=%d)\n",
@@ -6703,18 +6706,27 @@
                goto again;
 }
 
-static void
+static int
 key_acquire_sendup_mbuf_later(struct mbuf *m)
 {
 
        mutex_enter(&key_misc.lock);
+       /* Avoid queuing too much mbufs */
+       if (key_acquire_mbuf_count >= KEY_ACQUIRE_MBUF_MAX) {
+               mutex_exit(&key_misc.lock);
+               m_freem(m);
+               return ENOBUFS; /* XXX */
+       }
        /* Enqueue mbuf at the head of the list */
        m->m_nextpkt = key_acquire_mbuf_head;
        key_acquire_mbuf_head = m;
+       key_acquire_mbuf_count++;
        mutex_exit(&key_misc.lock);
 
        /* Kick the timer */
        key_timehandler(NULL);
+
+       return 0;
 }
 
 #ifndef IPSEC_NONBLOCK_ACQUIRE