[NET]: Convert init_timer into setup_timer
[linux-2.6.git] / net / ipv4 / inet_fragment.c
1 /*
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>
19 #include <linux/random.h>
20 #include <linux/skbuff.h>
21 #include <linux/rtnetlink.h>
22
23 #include <net/inet_frag.h>
24
25 static 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
53 void 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
69         setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
70                         (unsigned long)f);
71         f->secret_timer.expires = jiffies + f->ctl->secret_interval;
72         add_timer(&f->secret_timer);
73 }
74 EXPORT_SYMBOL(inet_frags_init);
75
76 void inet_frags_fini(struct inet_frags *f)
77 {
78         del_timer(&f->secret_timer);
79 }
80 EXPORT_SYMBOL(inet_frags_fini);
81
82 static 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
91 void 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
103 EXPORT_SYMBOL(inet_frag_kill);
104
105 static 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
117 void 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
138         if (f->destructor)
139                 f->destructor(q);
140         kfree(q);
141
142 }
143 EXPORT_SYMBOL(inet_frag_destroy);
144
145 int 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 }
175 EXPORT_SYMBOL(inet_frag_evictor);
176
177 static struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
178                 struct inet_frags *f, unsigned int hash, void *arg)
179 {
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) {
192                 if (f->match(qp, arg)) {
193                         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 }
212
213 static struct inet_frag_queue *inet_frag_alloc(struct inet_frags *f, void *arg)
214 {
215         struct inet_frag_queue *q;
216
217         q = kzalloc(f->qsize, GFP_ATOMIC);
218         if (q == NULL)
219                 return NULL;
220
221         f->constructor(q, arg);
222         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 }
229
230 static struct inet_frag_queue *inet_frag_create(struct inet_frags *f,
231                 void *arg, unsigned int hash)
232 {
233         struct inet_frag_queue *q;
234
235         q = inet_frag_alloc(f, arg);
236         if (q == NULL)
237                 return NULL;
238
239         return inet_frag_intern(q, f, hash, arg);
240 }
241
242 struct 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 }
260 EXPORT_SYMBOL(inet_frag_find);