7 files changed, 40 insertions, 33 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 625c8dda4be7..e8c304e37831 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -111,11 +111,6 @@ ipfrag_low_thresh - INTEGER
 ipfrag_time - INTEGER
         Time in seconds to keep an IP fragment in memory.
 
-ipfrag_secret_interval - INTEGER
-        Regeneration interval (in seconds) of the hash secret (or lifetime
-        for the hash secret) for IP fragments.
-        Default: 600
-
 ipfrag_max_dist - INTEGER
         ipfrag_max_dist is a non-negative integer value which defines the
         maximum "disorder" which is allowed among fragments which share a
@@ -1164,11 +1159,6 @@ ip6frag_low_thresh - INTEGER
 ip6frag_time - INTEGER
         Time in seconds to keep an IPv6 fragment in memory.
 
-ip6frag_secret_interval - INTEGER
-        Regeneration interval (in seconds) of the hash secret (or lifetime
-        for the hash secret) for IPv6 fragments.
-        Default: 600
-
 conf/default/*:
         Change the interface-specific default settings.
 
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 90d21ea62c59..d9cc5bb64854 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -58,11 +58,11 @@ struct inet_frags {
          * Its primarily a rebuild protection rwlock.
          */
         rwlock_t                lock ____cacheline_aligned_in_smp;
-        int                     secret_interval;
-        struct timer_list       secret_timer;
 
         struct work_struct      frags_work;
         unsigned int next_bucket;
+        unsigned long last_rebuild_jiffies;
+        bool rebuild;
 
         /* The first call to hashfn is responsible to initialize
          * rnd. This is best done with net_get_random_once.
diff --git a/net/ieee802154/reassembly.c b/net/ieee802154/reassembly.c
index b4bc7a50eccf..20d219682d84 100644
--- a/net/ieee802154/reassembly.c
+++ b/net/ieee802154/reassembly.c
@@ -419,10 +419,12 @@ static struct ctl_table lowpan_frags_ns_ctl_table[] = {
         { }
 };
 
+/* secret interval has been deprecated */
+static int lowpan_frags_secret_interval_unused;
 static struct ctl_table lowpan_frags_ctl_table[] = {
         {
                 .procname       = "6lowpanfrag_secret_interval",
-                .data           = &lowpan_frags.secret_interval,
+                .data           = &lowpan_frags_secret_interval_unused,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec_jiffies,
@@ -562,7 +564,6 @@ int __init lowpan_net_frag_init(void)
         lowpan_frags.qsize = sizeof(struct frag_queue);
         lowpan_frags.match = lowpan_frag_match;
         lowpan_frags.frag_expire = lowpan_frag_expire;
-        lowpan_frags.secret_interval = 10 * 60 * HZ;
         inet_frags_init(&lowpan_frags);
 
         return ret;
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index 198a5ed7a815..58d4c38534f6 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -28,6 +28,9 @@
 #define INETFRAGS_EVICT_BUCKETS   128
 #define INETFRAGS_EVICT_MAX       512
 
+/* don't rebuild inetfrag table with new secret more often than this */
+#define INETFRAGS_MIN_REBUILD_INTERVAL (5 * HZ)
+
 /* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
  * Value : 0xff if frame should be dropped.
  *         0 or INET_ECN_CE value, to be ORed in to final iph->tos field
@@ -55,16 +58,24 @@ inet_frag_hashfn(const struct inet_frags *f, const struct inet_frag_queue *q)
         return f->hashfn(q) & (INETFRAGS_HASHSZ - 1);
 }
 
-static void inet_frag_secret_rebuild(unsigned long dummy)
+static bool inet_frag_may_rebuild(struct inet_frags *f)
+{
+        return time_after(jiffies,
+               f->last_rebuild_jiffies + INETFRAGS_MIN_REBUILD_INTERVAL);
+}
+
+static void inet_frag_secret_rebuild(struct inet_frags *f)
 {
-        struct inet_frags *f = (struct inet_frags *)dummy;
-        unsigned long now = jiffies;
         int i;
 
         /* Per bucket lock NOT needed here, due to write lock protection */
-        write_lock(&f->lock);
+        write_lock_bh(&f->lock);
+
+        if (!inet_frag_may_rebuild(f))
+                goto out;
 
         get_random_bytes(&f->rnd, sizeof(u32));
+
         for (i = 0; i < INETFRAGS_HASHSZ; i++) {
                 struct inet_frag_bucket *hb;
                 struct inet_frag_queue *q;
@@ -85,9 +96,11 @@ static void inet_frag_secret_rebuild(unsigned long dummy)
                         }
                 }
         }
-        write_unlock(&f->lock);
 
-        mod_timer(&f->secret_timer, now + f->secret_interval);
+        f->rebuild = false;
+        f->last_rebuild_jiffies = jiffies;
+out:
+        write_unlock_bh(&f->lock);
 }
 
 static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
@@ -162,6 +175,8 @@ static void inet_frag_worker(struct work_struct *work)
         f->next_bucket = i;
 
         read_unlock_bh(&f->lock);
+        if (f->rebuild && inet_frag_may_rebuild(f))
+                inet_frag_secret_rebuild(f);
 }
 
 static void inet_frag_schedule_worker(struct inet_frags *f)
@@ -183,11 +198,7 @@ void inet_frags_init(struct inet_frags *f)
                 INIT_HLIST_HEAD(&hb->chain);
         }
         rwlock_init(&f->lock);
-
-        setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
-                        (unsigned long)f);
-        f->secret_timer.expires = jiffies + f->secret_interval;
-        add_timer(&f->secret_timer);
+        f->last_rebuild_jiffies = 0;
 }
 EXPORT_SYMBOL(inet_frags_init);
 
@@ -199,7 +210,6 @@ EXPORT_SYMBOL(inet_frags_init_net);
 
 void inet_frags_fini(struct inet_frags *f)
 {
-        del_timer(&f->secret_timer);
         cancel_work_sync(&f->frags_work);
 }
 EXPORT_SYMBOL(inet_frags_fini);
@@ -399,8 +409,13 @@ struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
 
         if (depth <= INETFRAGS_MAXDEPTH)
                 return inet_frag_create(nf, f, key);
-        else
-                return ERR_PTR(-ENOBUFS);
+
+        if (inet_frag_may_rebuild(f)) {
+                f->rebuild = true;
+                inet_frag_schedule_worker(f);
+        }
+
+        return ERR_PTR(-ENOBUFS);
 }
 EXPORT_SYMBOL(inet_frag_find);
 
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 8fbeee495037..44e591a7e03f 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -720,10 +720,12 @@ static struct ctl_table ip4_frags_ns_ctl_table[] = {
         { }
 };
 
+/* secret interval has been deprecated */
+static int ip4_frags_secret_interval_unused;
 static struct ctl_table ip4_frags_ctl_table[] = {
         {
                 .procname       = "ipfrag_secret_interval",
-                .data           = &ip4_frags.secret_interval,
+                .data           = &ip4_frags_secret_interval_unused,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec_jiffies,
@@ -853,6 +855,5 @@ void __init ipfrag_init(void)
         ip4_frags.qsize = sizeof(struct ipq);
         ip4_frags.match = ip4_frag_match;
         ip4_frags.frag_expire = ip_expire;
-        ip4_frags.secret_interval = 10 * 60 * HZ;
         inet_frags_init(&ip4_frags);
 }
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index fb0f72a0ff31..3b3ef9774cc2 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -669,7 +669,6 @@ int nf_ct_frag6_init(void)
         nf_frags.qsize = sizeof(struct frag_queue);
         nf_frags.match = ip6_frag_match;
         nf_frags.frag_expire = nf_ct_frag6_expire;
-        nf_frags.secret_interval = 10 * 60 * HZ;
         inet_frags_init(&nf_frags);
 
         ret = register_pernet_subsys(&nf_ct_net_ops);
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index af85551682c2..987fea46b915 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -604,10 +604,12 @@ static struct ctl_table ip6_frags_ns_ctl_table[] = {
         { }
 };
 
+/* secret interval has been deprecated */
+static int ip6_frags_secret_interval_unused;
 static struct ctl_table ip6_frags_ctl_table[] = {
         {
                 .procname       = "ip6frag_secret_interval",
-                .data           = &ip6_frags.secret_interval,
+                .data           = &ip6_frags_secret_interval_unused,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec_jiffies,
@@ -737,7 +739,6 @@ int __init ipv6_frag_init(void)
         ip6_frags.qsize = sizeof(struct frag_queue);
         ip6_frags.match = ip6_frag_match;
         ip6_frags.frag_expire = ip6_frag_expire;
-        ip6_frags.secret_interval = 10 * 60 * HZ;
         inet_frags_init(&ip6_frags);
 out:
         return ret;