1 files changed, 233 insertions, 0 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
new file mode 100644
index 000000000000..c03e5f5859e1
--- /dev/null
+++ b/net/ipv4/inet_fragment.c
@@ -0,0 +1,233 @@
+/*
+ * 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 <linux/slab.h>
+
+#include <net/sock.h>
+#include <net/inet_frag.h>
+#include <net/inet_ecn.h>
+
+/* 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
+ */
+const u8 ip_frag_ecn_table[16] = {
+	/* at least one fragment had CE, and others ECT_0 or ECT_1 */
+	[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0]			= INET_ECN_CE,
+	[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1]			= INET_ECN_CE,
+	[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1]	= INET_ECN_CE,
+
+	/* invalid combinations : drop frame */
+	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff,
+	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff,
+	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff,
+	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
+	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff,
+	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff,
+	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
+};
+EXPORT_SYMBOL(ip_frag_ecn_table);
+
+int inet_frags_init(struct inet_frags *f)
+{
+	f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0,
+					    NULL);
+	if (!f->frags_cachep)
+		return -ENOMEM;
+
+	return 0;
+}
+EXPORT_SYMBOL(inet_frags_init);
+
+void inet_frags_fini(struct inet_frags *f)
+{
+	/* We must wait that all inet_frag_destroy_rcu() have completed. */
+	rcu_barrier();
+
+	kmem_cache_destroy(f->frags_cachep);
+	f->frags_cachep = NULL;
+}
+EXPORT_SYMBOL(inet_frags_fini);
+
+static void inet_frags_free_cb(void *ptr, void *arg)
+{
+	struct inet_frag_queue *fq = ptr;
+
+	/* If we can not cancel the timer, it means this frag_queue
+	 * is already disappearing, we have nothing to do.
+	 * Otherwise, we own a refcount until the end of this function.
+	 */
+	if (!del_timer(&fq->timer))
+		return;
+
+	spin_lock_bh(&fq->lock);
+	if (!(fq->flags & INET_FRAG_COMPLETE)) {
+		fq->flags |= INET_FRAG_COMPLETE;
+		atomic_dec(&fq->refcnt);
+	}
+	spin_unlock_bh(&fq->lock);
+
+	inet_frag_put(fq);
+}
+
+void inet_frags_exit_net(struct netns_frags *nf)
+{
+	nf->high_thresh = 0; /* prevent creation of new frags */
+
+	rhashtable_free_and_destroy(&nf->rhashtable, inet_frags_free_cb, NULL);
+}
+EXPORT_SYMBOL(inet_frags_exit_net);
+
+void inet_frag_kill(struct inet_frag_queue *fq)
+{
+	if (del_timer(&fq->timer))
+		atomic_dec(&fq->refcnt);
+
+	if (!(fq->flags & INET_FRAG_COMPLETE)) {
+		struct netns_frags *nf = fq->net;
+
+		fq->flags |= INET_FRAG_COMPLETE;
+		rhashtable_remove_fast(&nf->rhashtable, &fq->node, nf->f->rhash_params);
+		atomic_dec(&fq->refcnt);
+	}
+}
+EXPORT_SYMBOL(inet_frag_kill);
+
+static inline void frag_kfree_skb(struct netns_frags *nf, struct inet_frags *f,
+				  struct sk_buff *skb)
+{
+	if (f->skb_free)
+		f->skb_free(skb);
+	kfree_skb(skb);
+}
+
+static void inet_frag_destroy_rcu(struct rcu_head *head)
+{
+	struct inet_frag_queue *q = container_of(head, struct inet_frag_queue,
+						 rcu);
+	struct inet_frags *f = q->net->f;
+
+	if (f->destructor)
+		f->destructor(q);
+	kmem_cache_free(f->frags_cachep, q);
+}
+
+void inet_frag_destroy(struct inet_frag_queue *q)
+{
+	struct sk_buff *fp;
+	struct netns_frags *nf;
+	unsigned int sum, sum_truesize = 0;
+	struct inet_frags *f;
+
+	WARN_ON(!(q->flags & INET_FRAG_COMPLETE));
+	WARN_ON(del_timer(&q->timer) != 0);
+
+	/* Release all fragment data. */
+	fp = q->fragments;
+	nf = q->net;
+	f = nf->f;
+	if (fp) {
+		do {
+			struct sk_buff *xp = fp->next;
+
+			sum_truesize += fp->truesize;
+			frag_kfree_skb(nf, f, fp);
+			fp = xp;
+		} while (fp);
+	} else {
+		sum_truesize = inet_frag_rbtree_purge(&q->rb_fragments);
+	}
+	sum = sum_truesize + f->qsize;
+
+	call_rcu(&q->rcu, inet_frag_destroy_rcu);
+
+	sub_frag_mem_limit(nf, sum);
+}
+EXPORT_SYMBOL(inet_frag_destroy);
+
+static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
+					       struct inet_frags *f,
+					       void *arg)
+{
+	struct inet_frag_queue *q;
+
+	if (!nf->high_thresh || frag_mem_limit(nf) > nf->high_thresh)
+		return NULL;
+
+	q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC);
+	if (!q)
+		return NULL;
+
+	q->net = nf;
+	f->constructor(q, arg);
+	add_frag_mem_limit(nf, f->qsize);
+
+	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
+	spin_lock_init(&q->lock);
+	atomic_set(&q->refcnt, 3);
+
+	return q;
+}
+
+static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
+						void *arg,
+						struct inet_frag_queue **prev)
+{
+	struct inet_frags *f = nf->f;
+	struct inet_frag_queue *q;
+
+	q = inet_frag_alloc(nf, f, arg);
+	if (!q) {
+		*prev = ERR_PTR(-ENOMEM);
+		return NULL;
+	}
+	mod_timer(&q->timer, jiffies + nf->timeout);
+
+	*prev = rhashtable_lookup_get_insert_key(&nf->rhashtable, &q->key,
+						 &q->node, f->rhash_params);
+	if (*prev) {
+		q->flags |= INET_FRAG_COMPLETE;
+		inet_frag_kill(q);
+		inet_frag_destroy(q);
+		return NULL;
+	}
+	return q;
+}
+EXPORT_SYMBOL(inet_frag_create);
+
+/* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */
+struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, void *key)
+{
+	struct inet_frag_queue *fq = NULL, *prev;
+
+	rcu_read_lock();
+	prev = rhashtable_lookup(&nf->rhashtable, key, nf->f->rhash_params);
+	if (!prev)
+		fq = inet_frag_create(nf, key, &prev);
+	if (prev && !IS_ERR(prev)) {
+		fq = prev;
+		if (!atomic_inc_not_zero(&fq->refcnt))
+			fq = NULL;
+	}
+	rcu_read_unlock();
+	return fq;
+}
+EXPORT_SYMBOL(inet_frag_find);