1 files changed, 361 insertions, 0 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
new file mode 100644
index 00000000000..3b01959bf4b
--- /dev/null
+++ b/net/ipv4/inet_fragment.c
@@ -0,0 +1,361 @@
+/*
+ * 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);
+
+static void inet_frag_secret_rebuild(unsigned long dummy)
+{
+	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);
+
+	get_random_bytes(&f->rnd, sizeof(u32));
+	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
+		struct inet_frag_bucket *hb;
+		struct inet_frag_queue *q;
+		struct hlist_node *n;
+
+		hb = &f->hash[i];
+		hlist_for_each_entry_safe(q, n, &hb->chain, list) {
+			unsigned int hval = f->hashfn(q);
+
+			if (hval != i) {
+				struct inet_frag_bucket *hb_dest;
+
+				hlist_del(&q->list);
+
+				/* Relink to new hash chain. */
+				hb_dest = &f->hash[hval];
+				hlist_add_head(&q->list, &hb_dest->chain);
+			}
+		}
+	}
+	write_unlock(&f->lock);
+
+	mod_timer(&f->secret_timer, now + f->secret_interval);
+}
+
+void inet_frags_init(struct inet_frags *f)
+{
+	int i;
+
+	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
+		struct inet_frag_bucket *hb = &f->hash[i];
+
+		spin_lock_init(&hb->chain_lock);
+		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);
+}
+EXPORT_SYMBOL(inet_frags_init);
+
+void inet_frags_init_net(struct netns_frags *nf)
+{
+	nf->nqueues = 0;
+	init_frag_mem_limit(nf);
+	INIT_LIST_HEAD(&nf->lru_list);
+	spin_lock_init(&nf->lru_lock);
+}
+EXPORT_SYMBOL(inet_frags_init_net);
+
+void inet_frags_fini(struct inet_frags *f)
+{
+	del_timer(&f->secret_timer);
+}
+EXPORT_SYMBOL(inet_frags_fini);
+
+void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f)
+{
+	nf->low_thresh = 0;
+
+	local_bh_disable();
+	inet_frag_evictor(nf, f, true);
+	local_bh_enable();
+
+	percpu_counter_destroy(&nf->mem);
+}
+EXPORT_SYMBOL(inet_frags_exit_net);
+
+static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
+{
+	struct inet_frag_bucket *hb;
+	unsigned int hash;
+
+	read_lock(&f->lock);
+	hash = f->hashfn(fq);
+	hb = &f->hash[hash];
+
+	spin_lock(&hb->chain_lock);
+	hlist_del(&fq->list);
+	spin_unlock(&hb->chain_lock);
+
+	read_unlock(&f->lock);
+	inet_frag_lru_del(fq);
+}
+
+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 & INET_FRAG_COMPLETE)) {
+		fq_unlink(fq, f);
+		atomic_dec(&fq->refcnt);
+		fq->last_in |= INET_FRAG_COMPLETE;
+	}
+}
+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);
+}
+
+void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
+					int *work)
+{
+	struct sk_buff *fp;
+	struct netns_frags *nf;
+	unsigned int sum, sum_truesize = 0;
+
+	WARN_ON(!(q->last_in & INET_FRAG_COMPLETE));
+	WARN_ON(del_timer(&q->timer) != 0);
+
+	/* Release all fragment data. */
+	fp = q->fragments;
+	nf = q->net;
+	while (fp) {
+		struct sk_buff *xp = fp->next;
+
+		sum_truesize += fp->truesize;
+		frag_kfree_skb(nf, f, fp);
+		fp = xp;
+	}
+	sum = sum_truesize + f->qsize;
+	if (work)
+		*work -= sum;
+	sub_frag_mem_limit(q, sum);
+
+	if (f->destructor)
+		f->destructor(q);
+	kfree(q);
+
+}
+EXPORT_SYMBOL(inet_frag_destroy);
+
+int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force)
+{
+	struct inet_frag_queue *q;
+	int work, evicted = 0;
+
+	if (!force) {
+		if (frag_mem_limit(nf) <= nf->high_thresh)
+			return 0;
+	}
+
+	work = frag_mem_limit(nf) - nf->low_thresh;
+	while (work > 0 || force) {
+		spin_lock(&nf->lru_lock);
+
+		if (list_empty(&nf->lru_list)) {
+			spin_unlock(&nf->lru_lock);
+			break;
+		}
+
+		q = list_first_entry(&nf->lru_list,
+				struct inet_frag_queue, lru_list);
+		atomic_inc(&q->refcnt);
+		/* Remove q from list to avoid several CPUs grabbing it */
+		list_del_init(&q->lru_list);
+
+		spin_unlock(&nf->lru_lock);
+
+		spin_lock(&q->lock);
+		if (!(q->last_in & INET_FRAG_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);
+
+static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf,
+		struct inet_frag_queue *qp_in, struct inet_frags *f,
+		void *arg)
+{
+	struct inet_frag_bucket *hb;
+	struct inet_frag_queue *qp;
+	unsigned int hash;
+
+	read_lock(&f->lock); /* Protects against hash rebuild */
+	/*
+	 * While we stayed w/o the lock other CPU could update
+	 * the rnd seed, so we need to re-calculate the hash
+	 * chain. Fortunatelly the qp_in can be used to get one.
+	 */
+	hash = f->hashfn(qp_in);
+	hb = &f->hash[hash];
+	spin_lock(&hb->chain_lock);
+
+#ifdef CONFIG_SMP
+	/* With SMP race we have to recheck hash table, because
+	 * such entry could be created on other cpu, while we
+	 * released the hash bucket lock.
+	 */
+	hlist_for_each_entry(qp, &hb->chain, list) {
+		if (qp->net == nf && f->match(qp, arg)) {
+			atomic_inc(&qp->refcnt);
+			spin_unlock(&hb->chain_lock);
+			read_unlock(&f->lock);
+			qp_in->last_in |= INET_FRAG_COMPLETE;
+			inet_frag_put(qp_in, f);
+			return qp;
+		}
+	}
+#endif
+	qp = qp_in;
+	if (!mod_timer(&qp->timer, jiffies + nf->timeout))
+		atomic_inc(&qp->refcnt);
+
+	atomic_inc(&qp->refcnt);
+	hlist_add_head(&qp->list, &hb->chain);
+	inet_frag_lru_add(nf, qp);
+	spin_unlock(&hb->chain_lock);
+	read_unlock(&f->lock);
+
+	return qp;
+}
+
+static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
+		struct inet_frags *f, void *arg)
+{
+	struct inet_frag_queue *q;
+
+	q = kzalloc(f->qsize, GFP_ATOMIC);
+	if (q == NULL)
+		return NULL;
+
+	q->net = nf;
+	f->constructor(q, arg);
+	add_frag_mem_limit(q, f->qsize);
+
+	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
+	spin_lock_init(&q->lock);
+	atomic_set(&q->refcnt, 1);
+	INIT_LIST_HEAD(&q->lru_list);
+
+	return q;
+}
+
+static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
+		struct inet_frags *f, void *arg)
+{
+	struct inet_frag_queue *q;
+
+	q = inet_frag_alloc(nf, f, arg);
+	if (q == NULL)
+		return NULL;
+
+	return inet_frag_intern(nf, q, f, arg);
+}
+
+struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
+		struct inet_frags *f, void *key, unsigned int hash)
+	__releases(&f->lock)
+{
+	struct inet_frag_bucket *hb;
+	struct inet_frag_queue *q;
+	int depth = 0;
+
+	hb = &f->hash[hash];
+
+	spin_lock(&hb->chain_lock);
+	hlist_for_each_entry(q, &hb->chain, list) {
+		if (q->net == nf && f->match(q, key)) {
+			atomic_inc(&q->refcnt);
+			spin_unlock(&hb->chain_lock);
+			read_unlock(&f->lock);
+			return q;
+		}
+		depth++;
+	}
+	spin_unlock(&hb->chain_lock);
+	read_unlock(&f->lock);
+
+	if (depth <= INETFRAGS_MAXDEPTH)
+		return inet_frag_create(nf, f, key);
+	else
+		return ERR_PTR(-ENOBUFS);
+}
+EXPORT_SYMBOL(inet_frag_find);
+
+void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
+				   const char *prefix)
+{
+	static const char msg[] = "inet_frag_find: Fragment hash bucket"
+		" list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
+		". Dropping fragment.\n";
+
+	if (PTR_ERR(q) == -ENOBUFS)
+		LIMIT_NETDEBUG(KERN_WARNING "%s%s", prefix, msg);
+}
+EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);