blob: 737910767ff1a3aac8440043bd33d7f6a0c45bee [file] [log] [blame]
Pavel Emelyanov7eb95152007-10-15 02:31:52 -07001/*
2 * inet fragments management
3 *
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.
8 *
9 * Authors: Pavel Emelyanov <xemul@openvz.org>
10 * Started as consolidation of ipv4/ip_fragment.c,
11 * ipv6/reassembly. and ipv6 nf conntrack reassembly
12 */
13
14#include <linux/list.h>
15#include <linux/spinlock.h>
16#include <linux/module.h>
17#include <linux/timer.h>
18#include <linux/mm.h>
Pavel Emelyanov321a3a92007-10-15 02:38:08 -070019#include <linux/random.h>
Pavel Emelyanov1e4b8282007-10-15 02:39:14 -070020#include <linux/skbuff.h>
21#include <linux/rtnetlink.h>
Pavel Emelyanov7eb95152007-10-15 02:31:52 -070022
23#include <net/inet_frag.h>
24
Pavel Emelyanov321a3a92007-10-15 02:38:08 -070025static void inet_frag_secret_rebuild(unsigned long dummy)
26{
27 struct inet_frags *f = (struct inet_frags *)dummy;
28 unsigned long now = jiffies;
29 int i;
30
31 write_lock(&f->lock);
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;
36
37 hlist_for_each_entry_safe(q, p, n, &f->hash[i], list) {
38 unsigned int hval = f->hashfn(q);
39
40 if (hval != i) {
41 hlist_del(&q->list);
42
43 /* Relink to new hash chain. */
44 hlist_add_head(&q->list, &f->hash[hval]);
45 }
46 }
47 }
48 write_unlock(&f->lock);
49
50 mod_timer(&f->secret_timer, now + f->ctl->secret_interval);
51}
52
Pavel Emelyanov7eb95152007-10-15 02:31:52 -070053void inet_frags_init(struct inet_frags *f)
54{
55 int i;
56
57 for (i = 0; i < INETFRAGS_HASHSZ; i++)
58 INIT_HLIST_HEAD(&f->hash[i]);
59
60 INIT_LIST_HEAD(&f->lru_list);
61 rwlock_init(&f->lock);
62
63 f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
64 (jiffies ^ (jiffies >> 6)));
65
66 f->nqueues = 0;
67 atomic_set(&f->mem, 0);
68
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -080069 setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
70 (unsigned long)f);
Pavel Emelyanov321a3a92007-10-15 02:38:08 -070071 f->secret_timer.expires = jiffies + f->ctl->secret_interval;
72 add_timer(&f->secret_timer);
Pavel Emelyanov7eb95152007-10-15 02:31:52 -070073}
74EXPORT_SYMBOL(inet_frags_init);
75
76void inet_frags_fini(struct inet_frags *f)
77{
Pavel Emelyanov321a3a92007-10-15 02:38:08 -070078 del_timer(&f->secret_timer);
Pavel Emelyanov7eb95152007-10-15 02:31:52 -070079}
80EXPORT_SYMBOL(inet_frags_fini);
Pavel Emelyanov277e6502007-10-15 02:37:18 -070081
82static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
83{
84 write_lock(&f->lock);
85 hlist_del(&fq->list);
86 list_del(&fq->lru_list);
87 f->nqueues--;
88 write_unlock(&f->lock);
89}
90
91void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
92{
93 if (del_timer(&fq->timer))
94 atomic_dec(&fq->refcnt);
95
96 if (!(fq->last_in & COMPLETE)) {
97 fq_unlink(fq, f);
98 atomic_dec(&fq->refcnt);
99 fq->last_in |= COMPLETE;
100 }
101}
102
103EXPORT_SYMBOL(inet_frag_kill);
Pavel Emelyanov1e4b8282007-10-15 02:39:14 -0700104
105static inline void frag_kfree_skb(struct inet_frags *f, struct sk_buff *skb,
106 int *work)
107{
108 if (work)
109 *work -= skb->truesize;
110
111 atomic_sub(skb->truesize, &f->mem);
112 if (f->skb_free)
113 f->skb_free(skb);
114 kfree_skb(skb);
115}
116
117void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
118 int *work)
119{
120 struct sk_buff *fp;
121
122 BUG_TRAP(q->last_in & COMPLETE);
123 BUG_TRAP(del_timer(&q->timer) == 0);
124
125 /* Release all fragment data. */
126 fp = q->fragments;
127 while (fp) {
128 struct sk_buff *xp = fp->next;
129
130 frag_kfree_skb(f, fp, work);
131 fp = xp;
132 }
133
134 if (work)
135 *work -= f->qsize;
136 atomic_sub(f->qsize, &f->mem);
137
Pavel Emelyanovc9547702007-10-17 19:48:26 -0700138 if (f->destructor)
139 f->destructor(q);
140 kfree(q);
Pavel Emelyanov1e4b8282007-10-15 02:39:14 -0700141
142}
143EXPORT_SYMBOL(inet_frag_destroy);
Pavel Emelyanov8e7999c2007-10-15 02:40:06 -0700144
145int inet_frag_evictor(struct inet_frags *f)
146{
147 struct inet_frag_queue *q;
148 int work, evicted = 0;
149
150 work = atomic_read(&f->mem) - f->ctl->low_thresh;
151 while (work > 0) {
152 read_lock(&f->lock);
153 if (list_empty(&f->lru_list)) {
154 read_unlock(&f->lock);
155 break;
156 }
157
158 q = list_first_entry(&f->lru_list,
159 struct inet_frag_queue, lru_list);
160 atomic_inc(&q->refcnt);
161 read_unlock(&f->lock);
162
163 spin_lock(&q->lock);
164 if (!(q->last_in & COMPLETE))
165 inet_frag_kill(q, f);
166 spin_unlock(&q->lock);
167
168 if (atomic_dec_and_test(&q->refcnt))
169 inet_frag_destroy(q, f, &work);
170 evicted++;
171 }
172
173 return evicted;
174}
175EXPORT_SYMBOL(inet_frag_evictor);
Pavel Emelyanov2588fe12007-10-17 19:44:34 -0700176
Pavel Emelyanovc6fda282007-10-17 19:46:47 -0700177static struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
Pavel Emelyanov48d60052007-10-17 19:47:56 -0700178 struct inet_frags *f, unsigned int hash, void *arg)
Pavel Emelyanov2588fe12007-10-17 19:44:34 -0700179{
180 struct inet_frag_queue *qp;
181#ifdef CONFIG_SMP
182 struct hlist_node *n;
183#endif
184
185 write_lock(&f->lock);
186#ifdef CONFIG_SMP
187 /* With SMP race we have to recheck hash table, because
188 * such entry could be created on other cpu, while we
189 * promoted read lock to write lock.
190 */
191 hlist_for_each_entry(qp, n, &f->hash[hash], list) {
Pavel Emelyanov48d60052007-10-17 19:47:56 -0700192 if (f->match(qp, arg)) {
Pavel Emelyanov2588fe12007-10-17 19:44:34 -0700193 atomic_inc(&qp->refcnt);
194 write_unlock(&f->lock);
195 qp_in->last_in |= COMPLETE;
196 inet_frag_put(qp_in, f);
197 return qp;
198 }
199 }
200#endif
201 qp = qp_in;
202 if (!mod_timer(&qp->timer, jiffies + f->ctl->timeout))
203 atomic_inc(&qp->refcnt);
204
205 atomic_inc(&qp->refcnt);
206 hlist_add_head(&qp->list, &f->hash[hash]);
207 list_add_tail(&qp->lru_list, &f->lru_list);
208 f->nqueues++;
209 write_unlock(&f->lock);
210 return qp;
211}
Pavel Emelyanove521db92007-10-17 19:45:23 -0700212
Pavel Emelyanovc6fda282007-10-17 19:46:47 -0700213static struct inet_frag_queue *inet_frag_alloc(struct inet_frags *f, void *arg)
Pavel Emelyanove521db92007-10-17 19:45:23 -0700214{
215 struct inet_frag_queue *q;
216
217 q = kzalloc(f->qsize, GFP_ATOMIC);
218 if (q == NULL)
219 return NULL;
220
Pavel Emelyanovc6fda282007-10-17 19:46:47 -0700221 f->constructor(q, arg);
Pavel Emelyanove521db92007-10-17 19:45:23 -0700222 atomic_add(f->qsize, &f->mem);
223 setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
224 spin_lock_init(&q->lock);
225 atomic_set(&q->refcnt, 1);
226
227 return q;
228}
Pavel Emelyanovc6fda282007-10-17 19:46:47 -0700229
Pavel Emelyanovabd65232007-10-17 19:47:21 -0700230static struct inet_frag_queue *inet_frag_create(struct inet_frags *f,
231 void *arg, unsigned int hash)
Pavel Emelyanovc6fda282007-10-17 19:46:47 -0700232{
233 struct inet_frag_queue *q;
234
235 q = inet_frag_alloc(f, arg);
236 if (q == NULL)
237 return NULL;
238
Pavel Emelyanov48d60052007-10-17 19:47:56 -0700239 return inet_frag_intern(q, f, hash, arg);
Pavel Emelyanovc6fda282007-10-17 19:46:47 -0700240}
Pavel Emelyanovabd65232007-10-17 19:47:21 -0700241
242struct inet_frag_queue *inet_frag_find(struct inet_frags *f, void *key,
243 unsigned int hash)
244{
245 struct inet_frag_queue *q;
246 struct hlist_node *n;
247
248 read_lock(&f->lock);
249 hlist_for_each_entry(q, n, &f->hash[hash], list) {
250 if (f->match(q, key)) {
251 atomic_inc(&q->refcnt);
252 read_unlock(&f->lock);
253 return q;
254 }
255 }
256 read_unlock(&f->lock);
257
258 return inet_frag_create(f, key, hash);
259}
260EXPORT_SYMBOL(inet_frag_find);