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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#include <linux/slab.h>
23
24#include <net/sock.h>
25#include <net/inet_frag.h>
26#include <net/inet_ecn.h>
27
28
29
30
31
32const u8 ip_frag_ecn_table[16] = {
33
34 [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = INET_ECN_CE,
35 [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
36 [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = INET_ECN_CE,
37
38
39 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff,
40 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff,
41 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff,
42 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
43 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff,
44 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff,
45 [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
46};
47EXPORT_SYMBOL(ip_frag_ecn_table);
48
49static void inet_frag_secret_rebuild(unsigned long dummy)
50{
51 struct inet_frags *f = (struct inet_frags *)dummy;
52 unsigned long now = jiffies;
53 int i;
54
55
56 write_lock(&f->lock);
57
58 get_random_bytes(&f->rnd, sizeof(u32));
59 for (i = 0; i < INETFRAGS_HASHSZ; i++) {
60 struct inet_frag_bucket *hb;
61 struct inet_frag_queue *q;
62 struct hlist_node *n;
63
64 hb = &f->hash[i];
65 hlist_for_each_entry_safe(q, n, &hb->chain, list) {
66 unsigned int hval = f->hashfn(q);
67
68 if (hval != i) {
69 struct inet_frag_bucket *hb_dest;
70
71 hlist_del(&q->list);
72
73
74 hb_dest = &f->hash[hval];
75 hlist_add_head(&q->list, &hb_dest->chain);
76 }
77 }
78 }
79 write_unlock(&f->lock);
80
81 mod_timer(&f->secret_timer, now + f->secret_interval);
82}
83
84void inet_frags_init(struct inet_frags *f)
85{
86 int i;
87
88 for (i = 0; i < INETFRAGS_HASHSZ; i++) {
89 struct inet_frag_bucket *hb = &f->hash[i];
90
91 spin_lock_init(&hb->chain_lock);
92 INIT_HLIST_HEAD(&hb->chain);
93 }
94 rwlock_init(&f->lock);
95
96 setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
97 (unsigned long)f);
98 f->secret_timer.expires = jiffies + f->secret_interval;
99 add_timer(&f->secret_timer);
100}
101EXPORT_SYMBOL(inet_frags_init);
102
103void inet_frags_init_net(struct netns_frags *nf)
104{
105 nf->nqueues = 0;
106 init_frag_mem_limit(nf);
107 INIT_LIST_HEAD(&nf->lru_list);
108 spin_lock_init(&nf->lru_lock);
109}
110EXPORT_SYMBOL(inet_frags_init_net);
111
112void inet_frags_fini(struct inet_frags *f)
113{
114 del_timer(&f->secret_timer);
115}
116EXPORT_SYMBOL(inet_frags_fini);
117
118void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f)
119{
120 nf->low_thresh = 0;
121
122 local_bh_disable();
123 inet_frag_evictor(nf, f, true);
124 local_bh_enable();
125}
126EXPORT_SYMBOL(inet_frags_exit_net);
127
128static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
129{
130 struct inet_frag_bucket *hb;
131 unsigned int hash;
132
133 read_lock(&f->lock);
134 hash = f->hashfn(fq);
135 hb = &f->hash[hash];
136
137 spin_lock(&hb->chain_lock);
138 hlist_del(&fq->list);
139 spin_unlock(&hb->chain_lock);
140
141 read_unlock(&f->lock);
142 inet_frag_lru_del(fq);
143}
144
145void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
146{
147 if (del_timer(&fq->timer))
148 atomic_dec(&fq->refcnt);
149
150 if (!(fq->last_in & INET_FRAG_COMPLETE)) {
151 fq_unlink(fq, f);
152 atomic_dec(&fq->refcnt);
153 fq->last_in |= INET_FRAG_COMPLETE;
154 }
155}
156EXPORT_SYMBOL(inet_frag_kill);
157
158static inline void frag_kfree_skb(struct netns_frags *nf, struct inet_frags *f,
159 struct sk_buff *skb)
160{
161 if (f->skb_free)
162 f->skb_free(skb);
163 kfree_skb(skb);
164}
165
166void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
167 int *work)
168{
169 struct sk_buff *fp;
170 struct netns_frags *nf;
171 unsigned int sum, sum_truesize = 0;
172
173 WARN_ON(!(q->last_in & INET_FRAG_COMPLETE));
174 WARN_ON(del_timer(&q->timer) != 0);
175
176
177 fp = q->fragments;
178 nf = q->net;
179 if (fp) {
180 do {
181 struct sk_buff *xp = fp->next;
182
183 sum_truesize += fp->truesize;
184 frag_kfree_skb(nf, f, fp);
185 fp = xp;
186 } while (fp);
187 } else {
188 sum_truesize = inet_frag_rbtree_purge(&q->rb_fragments);
189 }
190 sum = sum_truesize + f->qsize;
191 if (work)
192 *work -= sum;
193 sub_frag_mem_limit(q, sum);
194
195 if (f->destructor)
196 f->destructor(q);
197 kfree(q);
198
199}
200EXPORT_SYMBOL(inet_frag_destroy);
201
202int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force)
203{
204 struct inet_frag_queue *q;
205 int work, evicted = 0;
206
207 if (!force) {
208 if (frag_mem_limit(nf) <= nf->high_thresh)
209 return 0;
210 }
211
212 work = frag_mem_limit(nf) - nf->low_thresh;
213 while (work > 0 || force) {
214 spin_lock(&nf->lru_lock);
215
216 if (list_empty(&nf->lru_list)) {
217 spin_unlock(&nf->lru_lock);
218 break;
219 }
220
221 q = list_first_entry(&nf->lru_list,
222 struct inet_frag_queue, lru_list);
223 atomic_inc(&q->refcnt);
224
225 list_del_init(&q->lru_list);
226
227 spin_unlock(&nf->lru_lock);
228
229 spin_lock(&q->lock);
230 if (!(q->last_in & INET_FRAG_COMPLETE))
231 inet_frag_kill(q, f);
232 spin_unlock(&q->lock);
233
234 if (atomic_dec_and_test(&q->refcnt))
235 inet_frag_destroy(q, f, &work);
236 evicted++;
237 }
238
239 return evicted;
240}
241EXPORT_SYMBOL(inet_frag_evictor);
242
243static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf,
244 struct inet_frag_queue *qp_in, struct inet_frags *f,
245 void *arg)
246{
247 struct inet_frag_bucket *hb;
248 struct inet_frag_queue *qp;
249 unsigned int hash;
250
251 read_lock(&f->lock);
252
253
254
255
256
257 hash = f->hashfn(qp_in);
258 hb = &f->hash[hash];
259 spin_lock(&hb->chain_lock);
260
261#ifdef CONFIG_SMP
262
263
264
265
266 hlist_for_each_entry(qp, &hb->chain, list) {
267 if (qp->net == nf && f->match(qp, arg)) {
268 atomic_inc(&qp->refcnt);
269 spin_unlock(&hb->chain_lock);
270 read_unlock(&f->lock);
271 qp_in->last_in |= INET_FRAG_COMPLETE;
272 inet_frag_put(qp_in, f);
273 return qp;
274 }
275 }
276#endif
277 qp = qp_in;
278 if (!mod_timer(&qp->timer, jiffies + nf->timeout))
279 atomic_inc(&qp->refcnt);
280
281 atomic_inc(&qp->refcnt);
282 hlist_add_head(&qp->list, &hb->chain);
283 inet_frag_lru_add(nf, qp);
284 spin_unlock(&hb->chain_lock);
285 read_unlock(&f->lock);
286
287 return qp;
288}
289
290static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
291 struct inet_frags *f, void *arg)
292{
293 struct inet_frag_queue *q;
294
295 q = kzalloc(f->qsize, GFP_ATOMIC);
296 if (q == NULL)
297 return NULL;
298
299 q->net = nf;
300 f->constructor(q, arg);
301 add_frag_mem_limit(q, f->qsize);
302
303 setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
304 spin_lock_init(&q->lock);
305 atomic_set(&q->refcnt, 1);
306 INIT_LIST_HEAD(&q->lru_list);
307
308 return q;
309}
310
311static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
312 struct inet_frags *f, void *arg)
313{
314 struct inet_frag_queue *q;
315
316 q = inet_frag_alloc(nf, f, arg);
317 if (q == NULL)
318 return NULL;
319
320 return inet_frag_intern(nf, q, f, arg);
321}
322
323struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
324 struct inet_frags *f, void *key, unsigned int hash)
325 __releases(&f->lock)
326{
327 struct inet_frag_bucket *hb;
328 struct inet_frag_queue *q;
329 int depth = 0;
330
331 hb = &f->hash[hash];
332
333 spin_lock(&hb->chain_lock);
334 hlist_for_each_entry(q, &hb->chain, list) {
335 if (q->net == nf && f->match(q, key)) {
336 atomic_inc(&q->refcnt);
337 spin_unlock(&hb->chain_lock);
338 read_unlock(&f->lock);
339 return q;
340 }
341 depth++;
342 }
343 spin_unlock(&hb->chain_lock);
344 read_unlock(&f->lock);
345
346 if (depth <= INETFRAGS_MAXDEPTH)
347 return inet_frag_create(nf, f, key);
348 else
349 return ERR_PTR(-ENOBUFS);
350}
351EXPORT_SYMBOL(inet_frag_find);
352
353void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
354 const char *prefix)
355{
356 static const char msg[] = "inet_frag_find: Fragment hash bucket"
357 " list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
358 ". Dropping fragment.\n";
359
360 if (PTR_ERR(q) == -ENOBUFS)
361 LIMIT_NETDEBUG(KERN_WARNING "%s%s", prefix, msg);
362}
363EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);
364
