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[/] [or1k_soc_on_altera_embedded_dev_kit/] [tags/] [linux-2.6/] [linux-2.6.24_or32_unified_v2.3/] [net/] [ipv4/] [inet_fragment.c] - Blame information for rev 8

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Line No. Rev Author Line
1 3 xianfeng 
/*
2 
 * inet fragments management
3 
 *
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 *              This program is free software; you can redistribute it and/or
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 *              modify it under the terms of the GNU General Public License
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 *              as published by the Free Software Foundation; either version
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 *              2 of the License, or (at your option) any later version.
8 
 *
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 *              Authors:        Pavel Emelyanov <xemul@openvz.org>
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 *                              Started as consolidation of ipv4/ip_fragment.c,
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 *                              ipv6/reassembly. and ipv6 nf conntrack reassembly
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 */
13 
 
14 
#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <linux/timer.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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#include <linux/skbuff.h>
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#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;
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        unsigned long now = jiffies;
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        int i;
30 
 
31 
        write_lock(&f->lock);
32 
        get_random_bytes(&f->rnd, sizeof(u32));
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        for (i = 0; i < INETFRAGS_HASHSZ; i++) {
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                struct inet_frag_queue *q;
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                struct hlist_node *p, *n;
36 
 
37 
                hlist_for_each_entry_safe(q, p, n, &f->hash[i], list) {
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                        unsigned int hval = f->hashfn(q);
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40 
                        if (hval != i) {
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                                hlist_del(&q->list);
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43 
                                /* Relink to new hash chain. */
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                                hlist_add_head(&q->list, &f->hash[hval]);
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                        }
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                }
47 
        }
48 
        write_unlock(&f->lock);
49 
 
50 
        mod_timer(&f->secret_timer, now + f->ctl->secret_interval);
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}
52 
 
53 
void inet_frags_init(struct inet_frags *f)
54 
{
55 
        int i;
56 
 
57 
        for (i = 0; i < INETFRAGS_HASHSZ; i++)
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                INIT_HLIST_HEAD(&f->hash[i]);
59 
 
60 
        INIT_LIST_HEAD(&f->lru_list);
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        rwlock_init(&f->lock);
62 
 
63 
        f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
64 
                                   (jiffies ^ (jiffies >> 6)));
65 
 
66 
        f->nqueues = 0;
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        atomic_set(&f->mem, 0);
68 
 
69 
        init_timer(&f->secret_timer);
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        f->secret_timer.function = inet_frag_secret_rebuild;
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        f->secret_timer.data = (unsigned long)f;
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        f->secret_timer.expires = jiffies + f->ctl->secret_interval;
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        add_timer(&f->secret_timer);
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}
75 
EXPORT_SYMBOL(inet_frags_init);
76 
 
77 
void inet_frags_fini(struct inet_frags *f)
78 
{
79 
        del_timer(&f->secret_timer);
80 
}
81 
EXPORT_SYMBOL(inet_frags_fini);
82 
 
83 
static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
84 
{
85 
        write_lock(&f->lock);
86 
        hlist_del(&fq->list);
87 
        list_del(&fq->lru_list);
88 
        f->nqueues--;
89 
        write_unlock(&f->lock);
90 
}
91 
 
92 
void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
93 
{
94 
        if (del_timer(&fq->timer))
95 
                atomic_dec(&fq->refcnt);
96 
 
97 
        if (!(fq->last_in & COMPLETE)) {
98 
                fq_unlink(fq, f);
99 
                atomic_dec(&fq->refcnt);
100 
                fq->last_in |= COMPLETE;
101 
        }
102 
}
103 
 
104 
EXPORT_SYMBOL(inet_frag_kill);
105 
 
106 
static inline void frag_kfree_skb(struct inet_frags *f, struct sk_buff *skb,
107 
                                                int *work)
108 
{
109 
        if (work)
110 
                *work -= skb->truesize;
111 
 
112 
        atomic_sub(skb->truesize, &f->mem);
113 
        if (f->skb_free)
114 
                f->skb_free(skb);
115 
        kfree_skb(skb);
116 
}
117 
 
118 
void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
119 
                                        int *work)
120 
{
121 
        struct sk_buff *fp;
122 
 
123 
        BUG_TRAP(q->last_in & COMPLETE);
124 
        BUG_TRAP(del_timer(&q->timer) == 0);
125 
 
126 
        /* Release all fragment data. */
127 
        fp = q->fragments;
128 
        while (fp) {
129 
                struct sk_buff *xp = fp->next;
130 
 
131 
                frag_kfree_skb(f, fp, work);
132 
                fp = xp;
133 
        }
134 
 
135 
        if (work)
136 
                *work -= f->qsize;
137 
        atomic_sub(f->qsize, &f->mem);
138 
 
139 
        if (f->destructor)
140 
                f->destructor(q);
141 
        kfree(q);
142 
 
143 
}
144 
EXPORT_SYMBOL(inet_frag_destroy);
145 
 
146 
int inet_frag_evictor(struct inet_frags *f)
147 
{
148 
        struct inet_frag_queue *q;
149 
        int work, evicted = 0;
150 
 
151 
        work = atomic_read(&f->mem) - f->ctl->low_thresh;
152 
        while (work > 0) {
153 
                read_lock(&f->lock);
154 
                if (list_empty(&f->lru_list)) {
155 
                        read_unlock(&f->lock);
156 
                        break;
157 
                }
158 
 
159 
                q = list_first_entry(&f->lru_list,
160 
                                struct inet_frag_queue, lru_list);
161 
                atomic_inc(&q->refcnt);
162 
                read_unlock(&f->lock);
163 
 
164 
                spin_lock(&q->lock);
165 
                if (!(q->last_in & COMPLETE))
166 
                        inet_frag_kill(q, f);
167 
                spin_unlock(&q->lock);
168 
 
169 
                if (atomic_dec_and_test(&q->refcnt))
170 
                        inet_frag_destroy(q, f, &work);
171 
                evicted++;
172 
        }
173 
 
174 
        return evicted;
175 
}
176 
EXPORT_SYMBOL(inet_frag_evictor);
177 
 
178 
static struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
179 
                struct inet_frags *f, unsigned int hash, void *arg)
180 
{
181 
        struct inet_frag_queue *qp;
182 
#ifdef CONFIG_SMP
183 
        struct hlist_node *n;
184 
#endif
185 
 
186 
        write_lock(&f->lock);
187 
#ifdef CONFIG_SMP
188 
        /* With SMP race we have to recheck hash table, because
189 
         * such entry could be created on other cpu, while we
190 
         * promoted read lock to write lock.
191 
         */
192 
        hlist_for_each_entry(qp, n, &f->hash[hash], list) {
193 
                if (f->match(qp, arg)) {
194 
                        atomic_inc(&qp->refcnt);
195 
                        write_unlock(&f->lock);
196 
                        qp_in->last_in |= COMPLETE;
197 
                        inet_frag_put(qp_in, f);
198 
                        return qp;
199 
                }
200 
        }
201 
#endif
202 
        qp = qp_in;
203 
        if (!mod_timer(&qp->timer, jiffies + f->ctl->timeout))
204 
                atomic_inc(&qp->refcnt);
205 
 
206 
        atomic_inc(&qp->refcnt);
207 
        hlist_add_head(&qp->list, &f->hash[hash]);
208 
        list_add_tail(&qp->lru_list, &f->lru_list);
209 
        f->nqueues++;
210 
        write_unlock(&f->lock);
211 
        return qp;
212 
}
213 
 
214 
static struct inet_frag_queue *inet_frag_alloc(struct inet_frags *f, void *arg)
215 
{
216 
        struct inet_frag_queue *q;
217 
 
218 
        q = kzalloc(f->qsize, GFP_ATOMIC);
219 
        if (q == NULL)
220 
                return NULL;
221 
 
222 
        f->constructor(q, arg);
223 
        atomic_add(f->qsize, &f->mem);
224 
        setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
225 
        spin_lock_init(&q->lock);
226 
        atomic_set(&q->refcnt, 1);
227 
 
228 
        return q;
229 
}
230 
 
231 
static struct inet_frag_queue *inet_frag_create(struct inet_frags *f,
232 
                void *arg, unsigned int hash)
233 
{
234 
        struct inet_frag_queue *q;
235 
 
236 
        q = inet_frag_alloc(f, arg);
237 
        if (q == NULL)
238 
                return NULL;
239 
 
240 
        return inet_frag_intern(q, f, hash, arg);
241 
}
242 
 
243 
struct inet_frag_queue *inet_frag_find(struct inet_frags *f, void *key,
244 
                unsigned int hash)
245 
{
246 
        struct inet_frag_queue *q;
247 
        struct hlist_node *n;
248 
 
249 
        read_lock(&f->lock);
250 
        hlist_for_each_entry(q, n, &f->hash[hash], list) {
251 
                if (f->match(q, key)) {
252 
                        atomic_inc(&q->refcnt);
253 
                        read_unlock(&f->lock);
254 
                        return q;
255 
                }
256 
        }
257 
        read_unlock(&f->lock);
258 
 
259 
        return inet_frag_create(f, key, hash);
260 
}
261 
EXPORT_SYMBOL(inet_frag_find);

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