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7eb95156 PE |
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> | |
321a3a99 | 19 | #include <linux/random.h> |
1e4b8287 PE |
20 | #include <linux/skbuff.h> |
21 | #include <linux/rtnetlink.h> | |
7eb95156 PE |
22 | |
23 | #include <net/inet_frag.h> | |
24 | ||
321a3a99 PE |
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 | ||
7eb95156 PE |
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 | ||
321a3a99 PE |
69 | init_timer(&f->secret_timer); |
70 | f->secret_timer.function = inet_frag_secret_rebuild; | |
71 | f->secret_timer.data = (unsigned long)f; | |
72 | f->secret_timer.expires = jiffies + f->ctl->secret_interval; | |
73 | add_timer(&f->secret_timer); | |
7eb95156 PE |
74 | } |
75 | EXPORT_SYMBOL(inet_frags_init); | |
76 | ||
77 | void inet_frags_fini(struct inet_frags *f) | |
78 | { | |
321a3a99 | 79 | del_timer(&f->secret_timer); |
7eb95156 PE |
80 | } |
81 | EXPORT_SYMBOL(inet_frags_fini); | |
277e650d PE |
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); | |
1e4b8287 PE |
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 | f->destructor(q); | |
140 | ||
141 | } | |
142 | EXPORT_SYMBOL(inet_frag_destroy); | |
8e7999c4 PE |
143 | |
144 | int inet_frag_evictor(struct inet_frags *f) | |
145 | { | |
146 | struct inet_frag_queue *q; | |
147 | int work, evicted = 0; | |
148 | ||
149 | work = atomic_read(&f->mem) - f->ctl->low_thresh; | |
150 | while (work > 0) { | |
151 | read_lock(&f->lock); | |
152 | if (list_empty(&f->lru_list)) { | |
153 | read_unlock(&f->lock); | |
154 | break; | |
155 | } | |
156 | ||
157 | q = list_first_entry(&f->lru_list, | |
158 | struct inet_frag_queue, lru_list); | |
159 | atomic_inc(&q->refcnt); | |
160 | read_unlock(&f->lock); | |
161 | ||
162 | spin_lock(&q->lock); | |
163 | if (!(q->last_in & COMPLETE)) | |
164 | inet_frag_kill(q, f); | |
165 | spin_unlock(&q->lock); | |
166 | ||
167 | if (atomic_dec_and_test(&q->refcnt)) | |
168 | inet_frag_destroy(q, f, &work); | |
169 | evicted++; | |
170 | } | |
171 | ||
172 | return evicted; | |
173 | } | |
174 | EXPORT_SYMBOL(inet_frag_evictor); | |
2588fe1d PE |
175 | |
176 | struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in, | |
177 | struct inet_frags *f, unsigned int hash) | |
178 | { | |
179 | struct inet_frag_queue *qp; | |
180 | #ifdef CONFIG_SMP | |
181 | struct hlist_node *n; | |
182 | #endif | |
183 | ||
184 | write_lock(&f->lock); | |
185 | #ifdef CONFIG_SMP | |
186 | /* With SMP race we have to recheck hash table, because | |
187 | * such entry could be created on other cpu, while we | |
188 | * promoted read lock to write lock. | |
189 | */ | |
190 | hlist_for_each_entry(qp, n, &f->hash[hash], list) { | |
191 | if (f->equal(qp, qp_in)) { | |
192 | atomic_inc(&qp->refcnt); | |
193 | write_unlock(&f->lock); | |
194 | qp_in->last_in |= COMPLETE; | |
195 | inet_frag_put(qp_in, f); | |
196 | return qp; | |
197 | } | |
198 | } | |
199 | #endif | |
200 | qp = qp_in; | |
201 | if (!mod_timer(&qp->timer, jiffies + f->ctl->timeout)) | |
202 | atomic_inc(&qp->refcnt); | |
203 | ||
204 | atomic_inc(&qp->refcnt); | |
205 | hlist_add_head(&qp->list, &f->hash[hash]); | |
206 | list_add_tail(&qp->lru_list, &f->lru_list); | |
207 | f->nqueues++; | |
208 | write_unlock(&f->lock); | |
209 | return qp; | |
210 | } | |
211 | EXPORT_SYMBOL(inet_frag_intern); | |
e521db9d PE |
212 | |
213 | struct inet_frag_queue *inet_frag_alloc(struct inet_frags *f) | |
214 | { | |
215 | struct inet_frag_queue *q; | |
216 | ||
217 | q = kzalloc(f->qsize, GFP_ATOMIC); | |
218 | if (q == NULL) | |
219 | return NULL; | |
220 | ||
221 | atomic_add(f->qsize, &f->mem); | |
222 | setup_timer(&q->timer, f->frag_expire, (unsigned long)q); | |
223 | spin_lock_init(&q->lock); | |
224 | atomic_set(&q->refcnt, 1); | |
225 | ||
226 | return q; | |
227 | } | |
228 | EXPORT_SYMBOL(inet_frag_alloc); |