1 files changed, 174 insertions, 0 deletions

diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
new file mode 100644
index 000000000000..484cf512858f
--- /dev/null
+++ b/net/ipv4/inet_fragment.c
@@ -0,0 +1,174 @@
+/*
+ * inet fragments management
+ *
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ *
+ *              Authors:        Pavel Emelyanov <xemul@openvz.org>
+ *                              Started as consolidation of ipv4/ip_fragment.c,
+ *                              ipv6/reassembly. and ipv6 nf conntrack reassembly
+ */
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/random.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+
+#include <net/inet_frag.h>
+
+static void inet_frag_secret_rebuild(unsigned long dummy)
+{
+        struct inet_frags *f = (struct inet_frags *)dummy;
+        unsigned long now = jiffies;
+        int i;
+
+        write_lock(&f->lock);
+        get_random_bytes(&f->rnd, sizeof(u32));
+        for (i = 0; i < INETFRAGS_HASHSZ; i++) {
+                struct inet_frag_queue *q;
+                struct hlist_node *p, *n;
+
+                hlist_for_each_entry_safe(q, p, n, &f->hash[i], list) {
+                        unsigned int hval = f->hashfn(q);
+
+                        if (hval != i) {
+                                hlist_del(&q->list);
+
+                                /* Relink to new hash chain. */
+                                hlist_add_head(&q->list, &f->hash[hval]);
+                        }
+                }
+        }
+        write_unlock(&f->lock);
+
+        mod_timer(&f->secret_timer, now + f->ctl->secret_interval);
+}
+
+void inet_frags_init(struct inet_frags *f)
+{
+        int i;
+
+        for (i = 0; i < INETFRAGS_HASHSZ; i++)
+                INIT_HLIST_HEAD(&f->hash[i]);
+
+        INIT_LIST_HEAD(&f->lru_list);
+        rwlock_init(&f->lock);
+
+        f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
+                                   (jiffies ^ (jiffies >> 6)));
+
+        f->nqueues = 0;
+        atomic_set(&f->mem, 0);
+
+        init_timer(&f->secret_timer);
+        f->secret_timer.function = inet_frag_secret_rebuild;
+        f->secret_timer.data = (unsigned long)f;
+        f->secret_timer.expires = jiffies + f->ctl->secret_interval;
+        add_timer(&f->secret_timer);
+}
+EXPORT_SYMBOL(inet_frags_init);
+
+void inet_frags_fini(struct inet_frags *f)
+{
+        del_timer(&f->secret_timer);
+}
+EXPORT_SYMBOL(inet_frags_fini);
+
+static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
+{
+        write_lock(&f->lock);
+        hlist_del(&fq->list);
+        list_del(&fq->lru_list);
+        f->nqueues--;
+        write_unlock(&f->lock);
+}
+
+void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
+{
+        if (del_timer(&fq->timer))
+                atomic_dec(&fq->refcnt);
+
+        if (!(fq->last_in & COMPLETE)) {
+                fq_unlink(fq, f);
+                atomic_dec(&fq->refcnt);
+                fq->last_in |= COMPLETE;
+        }
+}
+
+EXPORT_SYMBOL(inet_frag_kill);
+
+static inline void frag_kfree_skb(struct inet_frags *f, struct sk_buff *skb,
+                                                int *work)
+{
+        if (work)
+                *work -= skb->truesize;
+
+        atomic_sub(skb->truesize, &f->mem);
+        if (f->skb_free)
+                f->skb_free(skb);
+        kfree_skb(skb);
+}
+
+void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
+                                        int *work)
+{
+        struct sk_buff *fp;
+
+        BUG_TRAP(q->last_in & COMPLETE);
+        BUG_TRAP(del_timer(&q->timer) == 0);
+
+        /* Release all fragment data. */
+        fp = q->fragments;
+        while (fp) {
+                struct sk_buff *xp = fp->next;
+
+                frag_kfree_skb(f, fp, work);
+                fp = xp;
+        }
+
+        if (work)
+                *work -= f->qsize;
+        atomic_sub(f->qsize, &f->mem);
+
+        f->destructor(q);
+
+}
+EXPORT_SYMBOL(inet_frag_destroy);
+
+int inet_frag_evictor(struct inet_frags *f)
+{
+        struct inet_frag_queue *q;
+        int work, evicted = 0;
+
+        work = atomic_read(&f->mem) - f->ctl->low_thresh;
+        while (work > 0) {
+                read_lock(&f->lock);
+                if (list_empty(&f->lru_list)) {
+                        read_unlock(&f->lock);
+                        break;
+                }
+
+                q = list_first_entry(&f->lru_list,
+                                struct inet_frag_queue, lru_list);
+                atomic_inc(&q->refcnt);
+                read_unlock(&f->lock);
+
+                spin_lock(&q->lock);
+                if (!(q->last_in & COMPLETE))
+                        inet_frag_kill(q, f);
+                spin_unlock(&q->lock);
+
+                if (atomic_dec_and_test(&q->refcnt))
+                        inet_frag_destroy(q, f, &work);
+                evicted++;
+        }
+
+        return evicted;
+}
+EXPORT_SYMBOL(inet_frag_evictor);