2 * inet fragments management
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: Pavel Emelyanov <xemul@openvz.org>
10 * Started as consolidation of ipv4/ip_fragment.c,
11 * ipv6/reassembly. and ipv6 nf conntrack reassembly
14 #include <linux/list.h>
15 #include <linux/spinlock.h>
16 #include <linux/module.h>
17 #include <linux/timer.h>
19 #include <linux/random.h>
20 #include <linux/skbuff.h>
21 #include <linux/rtnetlink.h>
23 #include <net/inet_frag.h>
25 static void inet_frag_secret_rebuild(unsigned long dummy)
27 struct inet_frags *f = (struct inet_frags *)dummy;
28 unsigned long now = jiffies;
32 get_random_bytes(&f->rnd, sizeof(u32));
33 for (i = 0; i < INETFRAGS_HASHSZ; i++) {
34 struct inet_frag_queue *q;
35 struct hlist_node *p, *n;
37 hlist_for_each_entry_safe(q, p, n, &f->hash[i], list) {
38 unsigned int hval = f->hashfn(q);
43 /* Relink to new hash chain. */
44 hlist_add_head(&q->list, &f->hash[hval]);
48 write_unlock(&f->lock);
50 mod_timer(&f->secret_timer, now + f->ctl->secret_interval);
53 void inet_frags_init(struct inet_frags *f)
57 for (i = 0; i < INETFRAGS_HASHSZ; i++)
58 INIT_HLIST_HEAD(&f->hash[i]);
60 INIT_LIST_HEAD(&f->lru_list);
61 rwlock_init(&f->lock);
63 f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
64 (jiffies ^ (jiffies >> 6)));
66 atomic_set(&f->mem, 0);
68 setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
70 f->secret_timer.expires = jiffies + f->ctl->secret_interval;
71 add_timer(&f->secret_timer);
73 EXPORT_SYMBOL(inet_frags_init);
75 void inet_frags_init_net(struct netns_frags *nf)
79 EXPORT_SYMBOL(inet_frags_init_net);
81 void inet_frags_fini(struct inet_frags *f)
83 del_timer(&f->secret_timer);
85 EXPORT_SYMBOL(inet_frags_fini);
87 static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
91 list_del(&fq->lru_list);
93 write_unlock(&f->lock);
96 void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
98 if (del_timer(&fq->timer))
99 atomic_dec(&fq->refcnt);
101 if (!(fq->last_in & COMPLETE)) {
103 atomic_dec(&fq->refcnt);
104 fq->last_in |= COMPLETE;
108 EXPORT_SYMBOL(inet_frag_kill);
110 static inline void frag_kfree_skb(struct inet_frags *f, struct sk_buff *skb,
114 *work -= skb->truesize;
116 atomic_sub(skb->truesize, &f->mem);
122 void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
127 BUG_TRAP(q->last_in & COMPLETE);
128 BUG_TRAP(del_timer(&q->timer) == 0);
130 /* Release all fragment data. */
133 struct sk_buff *xp = fp->next;
135 frag_kfree_skb(f, fp, work);
141 atomic_sub(f->qsize, &f->mem);
148 EXPORT_SYMBOL(inet_frag_destroy);
150 int inet_frag_evictor(struct inet_frags *f)
152 struct inet_frag_queue *q;
153 int work, evicted = 0;
155 work = atomic_read(&f->mem) - f->ctl->low_thresh;
158 if (list_empty(&f->lru_list)) {
159 read_unlock(&f->lock);
163 q = list_first_entry(&f->lru_list,
164 struct inet_frag_queue, lru_list);
165 atomic_inc(&q->refcnt);
166 read_unlock(&f->lock);
169 if (!(q->last_in & COMPLETE))
170 inet_frag_kill(q, f);
171 spin_unlock(&q->lock);
173 if (atomic_dec_and_test(&q->refcnt))
174 inet_frag_destroy(q, f, &work);
180 EXPORT_SYMBOL(inet_frag_evictor);
182 static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf,
183 struct inet_frag_queue *qp_in, struct inet_frags *f,
184 unsigned int hash, void *arg)
186 struct inet_frag_queue *qp;
188 struct hlist_node *n;
191 write_lock(&f->lock);
193 /* With SMP race we have to recheck hash table, because
194 * such entry could be created on other cpu, while we
195 * promoted read lock to write lock.
197 hlist_for_each_entry(qp, n, &f->hash[hash], list) {
198 if (qp->net == nf && f->match(qp, arg)) {
199 atomic_inc(&qp->refcnt);
200 write_unlock(&f->lock);
201 qp_in->last_in |= COMPLETE;
202 inet_frag_put(qp_in, f);
208 if (!mod_timer(&qp->timer, jiffies + f->ctl->timeout))
209 atomic_inc(&qp->refcnt);
211 atomic_inc(&qp->refcnt);
212 hlist_add_head(&qp->list, &f->hash[hash]);
213 list_add_tail(&qp->lru_list, &f->lru_list);
215 write_unlock(&f->lock);
219 static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
220 struct inet_frags *f, void *arg)
222 struct inet_frag_queue *q;
224 q = kzalloc(f->qsize, GFP_ATOMIC);
228 f->constructor(q, arg);
229 atomic_add(f->qsize, &f->mem);
230 setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
231 spin_lock_init(&q->lock);
232 atomic_set(&q->refcnt, 1);
238 static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
239 struct inet_frags *f, void *arg, unsigned int hash)
241 struct inet_frag_queue *q;
243 q = inet_frag_alloc(nf, f, arg);
247 return inet_frag_intern(nf, q, f, hash, arg);
250 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
251 struct inet_frags *f, void *key, unsigned int hash)
253 struct inet_frag_queue *q;
254 struct hlist_node *n;
257 hlist_for_each_entry(q, n, &f->hash[hash], list) {
258 if (q->net == nf && f->match(q, key)) {
259 atomic_inc(&q->refcnt);
260 read_unlock(&f->lock);
264 read_unlock(&f->lock);
266 return inet_frag_create(nf, f, key, hash);
268 EXPORT_SYMBOL(inet_frag_find);