Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * INETPEER - A storage for permanent information about peers | |
3 | * | |
4 | * This source is covered by the GNU GPL, the same as all kernel sources. | |
5 | * | |
1da177e4 LT |
6 | * Authors: Andrey V. Savochkin <saw@msu.ru> |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/types.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/interrupt.h> | |
13 | #include <linux/spinlock.h> | |
14 | #include <linux/random.h> | |
1da177e4 LT |
15 | #include <linux/timer.h> |
16 | #include <linux/time.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/net.h> | |
20380731 | 20 | #include <net/ip.h> |
1da177e4 LT |
21 | #include <net/inetpeer.h> |
22 | ||
23 | /* | |
24 | * Theory of operations. | |
25 | * We keep one entry for each peer IP address. The nodes contains long-living | |
26 | * information about the peer which doesn't depend on routes. | |
27 | * At this moment this information consists only of ID field for the next | |
28 | * outgoing IP packet. This field is incremented with each packet as encoded | |
29 | * in inet_getid() function (include/net/inetpeer.h). | |
30 | * At the moment of writing this notes identifier of IP packets is generated | |
31 | * to be unpredictable using this code only for packets subjected | |
32 | * (actually or potentially) to defragmentation. I.e. DF packets less than | |
33 | * PMTU in size uses a constant ID and do not use this code (see | |
34 | * ip_select_ident() in include/net/ip.h). | |
35 | * | |
36 | * Route cache entries hold references to our nodes. | |
37 | * New cache entries get references via lookup by destination IP address in | |
38 | * the avl tree. The reference is grabbed only when it's needed i.e. only | |
39 | * when we try to output IP packet which needs an unpredictable ID (see | |
40 | * __ip_select_ident() in net/ipv4/route.c). | |
41 | * Nodes are removed only when reference counter goes to 0. | |
42 | * When it's happened the node may be removed when a sufficient amount of | |
43 | * time has been passed since its last use. The less-recently-used entry can | |
44 | * also be removed if the pool is overloaded i.e. if the total amount of | |
45 | * entries is greater-or-equal than the threshold. | |
46 | * | |
47 | * Node pool is organised as an AVL tree. | |
48 | * Such an implementation has been chosen not just for fun. It's a way to | |
49 | * prevent easy and efficient DoS attacks by creating hash collisions. A huge | |
50 | * amount of long living nodes in a single hash slot would significantly delay | |
51 | * lookups performed with disabled BHs. | |
52 | * | |
53 | * Serialisation issues. | |
aa1039e7 ED |
54 | * 1. Nodes may appear in the tree only with the pool lock held. |
55 | * 2. Nodes may disappear from the tree only with the pool lock held | |
1da177e4 LT |
56 | * AND reference count being 0. |
57 | * 3. Nodes appears and disappears from unused node list only under | |
58 | * "inet_peer_unused_lock". | |
59 | * 4. Global variable peer_total is modified under the pool lock. | |
60 | * 5. struct inet_peer fields modification: | |
61 | * avl_left, avl_right, avl_parent, avl_height: pool lock | |
d71209de | 62 | * unused: unused node list lock |
1da177e4 LT |
63 | * refcnt: atomically against modifications on other CPU; |
64 | * usually under some other lock to prevent node disappearing | |
65 | * dtime: unused node list lock | |
66 | * v4daddr: unchangeable | |
67 | * ip_id_count: idlock | |
68 | */ | |
69 | ||
e18b890b | 70 | static struct kmem_cache *peer_cachep __read_mostly; |
1da177e4 LT |
71 | |
72 | #define node_height(x) x->avl_height | |
d6cc1d64 ED |
73 | |
74 | #define peer_avl_empty ((struct inet_peer *)&peer_fake_node) | |
75 | static const struct inet_peer peer_fake_node = { | |
76 | .avl_left = peer_avl_empty, | |
77 | .avl_right = peer_avl_empty, | |
1da177e4 LT |
78 | .avl_height = 0 |
79 | }; | |
d6cc1d64 ED |
80 | |
81 | static struct { | |
82 | struct inet_peer *root; | |
aa1039e7 | 83 | spinlock_t lock; |
d6cc1d64 ED |
84 | int total; |
85 | } peers = { | |
86 | .root = peer_avl_empty, | |
aa1039e7 | 87 | .lock = __SPIN_LOCK_UNLOCKED(peers.lock), |
d6cc1d64 ED |
88 | .total = 0, |
89 | }; | |
1da177e4 LT |
90 | #define PEER_MAXDEPTH 40 /* sufficient for about 2^27 nodes */ |
91 | ||
1da177e4 | 92 | /* Exported for sysctl_net_ipv4. */ |
243bbcaa | 93 | int inet_peer_threshold __read_mostly = 65536 + 128; /* start to throw entries more |
1da177e4 | 94 | * aggressively at this stage */ |
243bbcaa ED |
95 | int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec */ |
96 | int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min */ | |
97 | int inet_peer_gc_mintime __read_mostly = 10 * HZ; | |
98 | int inet_peer_gc_maxtime __read_mostly = 120 * HZ; | |
1da177e4 | 99 | |
d6cc1d64 ED |
100 | static struct { |
101 | struct list_head list; | |
102 | spinlock_t lock; | |
103 | } unused_peers = { | |
104 | .list = LIST_HEAD_INIT(unused_peers.list), | |
105 | .lock = __SPIN_LOCK_UNLOCKED(unused_peers.lock), | |
106 | }; | |
1da177e4 LT |
107 | |
108 | static void peer_check_expire(unsigned long dummy); | |
8d06afab | 109 | static DEFINE_TIMER(peer_periodic_timer, peer_check_expire, 0, 0); |
1da177e4 | 110 | |
1da177e4 LT |
111 | |
112 | /* Called from ip_output.c:ip_init */ | |
113 | void __init inet_initpeers(void) | |
114 | { | |
115 | struct sysinfo si; | |
116 | ||
117 | /* Use the straight interface to information about memory. */ | |
118 | si_meminfo(&si); | |
119 | /* The values below were suggested by Alexey Kuznetsov | |
120 | * <kuznet@ms2.inr.ac.ru>. I don't have any opinion about the values | |
121 | * myself. --SAW | |
122 | */ | |
123 | if (si.totalram <= (32768*1024)/PAGE_SIZE) | |
124 | inet_peer_threshold >>= 1; /* max pool size about 1MB on IA32 */ | |
125 | if (si.totalram <= (16384*1024)/PAGE_SIZE) | |
126 | inet_peer_threshold >>= 1; /* about 512KB */ | |
127 | if (si.totalram <= (8192*1024)/PAGE_SIZE) | |
128 | inet_peer_threshold >>= 2; /* about 128KB */ | |
129 | ||
130 | peer_cachep = kmem_cache_create("inet_peer_cache", | |
131 | sizeof(struct inet_peer), | |
aa1039e7 | 132 | 0, SLAB_PANIC, |
20c2df83 | 133 | NULL); |
1da177e4 | 134 | |
1da177e4 LT |
135 | /* All the timers, started at system startup tend |
136 | to synchronize. Perturb it a bit. | |
137 | */ | |
138 | peer_periodic_timer.expires = jiffies | |
139 | + net_random() % inet_peer_gc_maxtime | |
140 | + inet_peer_gc_maxtime; | |
141 | add_timer(&peer_periodic_timer); | |
142 | } | |
143 | ||
144 | /* Called with or without local BH being disabled. */ | |
145 | static void unlink_from_unused(struct inet_peer *p) | |
146 | { | |
d6cc1d64 ED |
147 | if (!list_empty(&p->unused)) { |
148 | spin_lock_bh(&unused_peers.lock); | |
149 | list_del_init(&p->unused); | |
150 | spin_unlock_bh(&unused_peers.lock); | |
151 | } | |
1da177e4 LT |
152 | } |
153 | ||
243bbcaa ED |
154 | /* |
155 | * Called with local BH disabled and the pool lock held. | |
243bbcaa | 156 | */ |
d9319100 | 157 | #define lookup(_daddr, _stack) \ |
1da177e4 LT |
158 | ({ \ |
159 | struct inet_peer *u, **v; \ | |
aa1039e7 ED |
160 | \ |
161 | stackptr = _stack; \ | |
162 | *stackptr++ = &peers.root; \ | |
d6cc1d64 | 163 | for (u = peers.root; u != peer_avl_empty; ) { \ |
243bbcaa | 164 | if (_daddr == u->v4daddr) \ |
1da177e4 | 165 | break; \ |
243bbcaa | 166 | if ((__force __u32)_daddr < (__force __u32)u->v4daddr) \ |
1da177e4 LT |
167 | v = &u->avl_left; \ |
168 | else \ | |
169 | v = &u->avl_right; \ | |
aa1039e7 | 170 | *stackptr++ = v; \ |
1da177e4 LT |
171 | u = *v; \ |
172 | } \ | |
173 | u; \ | |
174 | }) | |
175 | ||
aa1039e7 ED |
176 | /* |
177 | * Called with rcu_read_lock_bh() | |
178 | * Because we hold no lock against a writer, its quite possible we fall | |
179 | * in an endless loop. | |
180 | * But every pointer we follow is guaranteed to be valid thanks to RCU. | |
181 | * We exit from this function if number of links exceeds PEER_MAXDEPTH | |
182 | */ | |
183 | static struct inet_peer *lookup_rcu_bh(__be32 daddr) | |
184 | { | |
185 | struct inet_peer *u = rcu_dereference_bh(peers.root); | |
186 | int count = 0; | |
187 | ||
188 | while (u != peer_avl_empty) { | |
189 | if (daddr == u->v4daddr) { | |
190 | if (unlikely(!atomic_inc_not_zero(&u->refcnt))) | |
191 | u = NULL; | |
192 | return u; | |
193 | } | |
194 | if ((__force __u32)daddr < (__force __u32)u->v4daddr) | |
195 | u = rcu_dereference_bh(u->avl_left); | |
196 | else | |
197 | u = rcu_dereference_bh(u->avl_right); | |
198 | if (unlikely(++count == PEER_MAXDEPTH)) | |
199 | break; | |
200 | } | |
201 | return NULL; | |
202 | } | |
203 | ||
204 | /* Called with local BH disabled and the pool lock held. */ | |
1da177e4 LT |
205 | #define lookup_rightempty(start) \ |
206 | ({ \ | |
207 | struct inet_peer *u, **v; \ | |
208 | *stackptr++ = &start->avl_left; \ | |
209 | v = &start->avl_left; \ | |
210 | for (u = *v; u->avl_right != peer_avl_empty; ) { \ | |
211 | v = &u->avl_right; \ | |
212 | *stackptr++ = v; \ | |
213 | u = *v; \ | |
214 | } \ | |
215 | u; \ | |
216 | }) | |
217 | ||
aa1039e7 | 218 | /* Called with local BH disabled and the pool lock held. |
1da177e4 | 219 | * Variable names are the proof of operation correctness. |
aa1039e7 ED |
220 | * Look into mm/map_avl.c for more detail description of the ideas. |
221 | */ | |
1da177e4 LT |
222 | static void peer_avl_rebalance(struct inet_peer **stack[], |
223 | struct inet_peer ***stackend) | |
224 | { | |
225 | struct inet_peer **nodep, *node, *l, *r; | |
226 | int lh, rh; | |
227 | ||
228 | while (stackend > stack) { | |
229 | nodep = *--stackend; | |
230 | node = *nodep; | |
231 | l = node->avl_left; | |
232 | r = node->avl_right; | |
233 | lh = node_height(l); | |
234 | rh = node_height(r); | |
235 | if (lh > rh + 1) { /* l: RH+2 */ | |
236 | struct inet_peer *ll, *lr, *lrl, *lrr; | |
237 | int lrh; | |
238 | ll = l->avl_left; | |
239 | lr = l->avl_right; | |
240 | lrh = node_height(lr); | |
241 | if (lrh <= node_height(ll)) { /* ll: RH+1 */ | |
242 | node->avl_left = lr; /* lr: RH or RH+1 */ | |
243 | node->avl_right = r; /* r: RH */ | |
244 | node->avl_height = lrh + 1; /* RH+1 or RH+2 */ | |
245 | l->avl_left = ll; /* ll: RH+1 */ | |
246 | l->avl_right = node; /* node: RH+1 or RH+2 */ | |
247 | l->avl_height = node->avl_height + 1; | |
248 | *nodep = l; | |
249 | } else { /* ll: RH, lr: RH+1 */ | |
250 | lrl = lr->avl_left; /* lrl: RH or RH-1 */ | |
251 | lrr = lr->avl_right; /* lrr: RH or RH-1 */ | |
252 | node->avl_left = lrr; /* lrr: RH or RH-1 */ | |
253 | node->avl_right = r; /* r: RH */ | |
254 | node->avl_height = rh + 1; /* node: RH+1 */ | |
255 | l->avl_left = ll; /* ll: RH */ | |
256 | l->avl_right = lrl; /* lrl: RH or RH-1 */ | |
257 | l->avl_height = rh + 1; /* l: RH+1 */ | |
258 | lr->avl_left = l; /* l: RH+1 */ | |
259 | lr->avl_right = node; /* node: RH+1 */ | |
260 | lr->avl_height = rh + 2; | |
261 | *nodep = lr; | |
262 | } | |
263 | } else if (rh > lh + 1) { /* r: LH+2 */ | |
264 | struct inet_peer *rr, *rl, *rlr, *rll; | |
265 | int rlh; | |
266 | rr = r->avl_right; | |
267 | rl = r->avl_left; | |
268 | rlh = node_height(rl); | |
269 | if (rlh <= node_height(rr)) { /* rr: LH+1 */ | |
270 | node->avl_right = rl; /* rl: LH or LH+1 */ | |
271 | node->avl_left = l; /* l: LH */ | |
272 | node->avl_height = rlh + 1; /* LH+1 or LH+2 */ | |
273 | r->avl_right = rr; /* rr: LH+1 */ | |
274 | r->avl_left = node; /* node: LH+1 or LH+2 */ | |
275 | r->avl_height = node->avl_height + 1; | |
276 | *nodep = r; | |
277 | } else { /* rr: RH, rl: RH+1 */ | |
278 | rlr = rl->avl_right; /* rlr: LH or LH-1 */ | |
279 | rll = rl->avl_left; /* rll: LH or LH-1 */ | |
280 | node->avl_right = rll; /* rll: LH or LH-1 */ | |
281 | node->avl_left = l; /* l: LH */ | |
282 | node->avl_height = lh + 1; /* node: LH+1 */ | |
283 | r->avl_right = rr; /* rr: LH */ | |
284 | r->avl_left = rlr; /* rlr: LH or LH-1 */ | |
285 | r->avl_height = lh + 1; /* r: LH+1 */ | |
286 | rl->avl_right = r; /* r: LH+1 */ | |
287 | rl->avl_left = node; /* node: LH+1 */ | |
288 | rl->avl_height = lh + 2; | |
289 | *nodep = rl; | |
290 | } | |
291 | } else { | |
292 | node->avl_height = (lh > rh ? lh : rh) + 1; | |
293 | } | |
294 | } | |
295 | } | |
296 | ||
aa1039e7 | 297 | /* Called with local BH disabled and the pool lock held. */ |
1da177e4 LT |
298 | #define link_to_pool(n) \ |
299 | do { \ | |
300 | n->avl_height = 1; \ | |
301 | n->avl_left = peer_avl_empty; \ | |
302 | n->avl_right = peer_avl_empty; \ | |
aa1039e7 | 303 | smp_wmb(); /* lockless readers can catch us now */ \ |
1da177e4 LT |
304 | **--stackptr = n; \ |
305 | peer_avl_rebalance(stack, stackptr); \ | |
d6cc1d64 | 306 | } while (0) |
1da177e4 | 307 | |
aa1039e7 ED |
308 | static void inetpeer_free_rcu(struct rcu_head *head) |
309 | { | |
310 | kmem_cache_free(peer_cachep, container_of(head, struct inet_peer, rcu)); | |
311 | } | |
312 | ||
1da177e4 LT |
313 | /* May be called with local BH enabled. */ |
314 | static void unlink_from_pool(struct inet_peer *p) | |
315 | { | |
316 | int do_free; | |
317 | ||
318 | do_free = 0; | |
319 | ||
aa1039e7 | 320 | spin_lock_bh(&peers.lock); |
1da177e4 | 321 | /* Check the reference counter. It was artificially incremented by 1 |
aa1039e7 ED |
322 | * in cleanup() function to prevent sudden disappearing. If we can |
323 | * atomically (because of lockless readers) take this last reference, | |
324 | * it's safe to remove the node and free it later. | |
325 | */ | |
326 | if (atomic_cmpxchg(&p->refcnt, 1, 0) == 1) { | |
1da177e4 LT |
327 | struct inet_peer **stack[PEER_MAXDEPTH]; |
328 | struct inet_peer ***stackptr, ***delp; | |
243bbcaa | 329 | if (lookup(p->v4daddr, stack) != p) |
1da177e4 LT |
330 | BUG(); |
331 | delp = stackptr - 1; /* *delp[0] == p */ | |
332 | if (p->avl_left == peer_avl_empty) { | |
333 | *delp[0] = p->avl_right; | |
334 | --stackptr; | |
335 | } else { | |
336 | /* look for a node to insert instead of p */ | |
337 | struct inet_peer *t; | |
338 | t = lookup_rightempty(p); | |
09a62660 | 339 | BUG_ON(*stackptr[-1] != t); |
1da177e4 LT |
340 | **--stackptr = t->avl_left; |
341 | /* t is removed, t->v4daddr > x->v4daddr for any | |
342 | * x in p->avl_left subtree. | |
343 | * Put t in the old place of p. */ | |
344 | *delp[0] = t; | |
345 | t->avl_left = p->avl_left; | |
346 | t->avl_right = p->avl_right; | |
347 | t->avl_height = p->avl_height; | |
09a62660 | 348 | BUG_ON(delp[1] != &p->avl_left); |
1da177e4 LT |
349 | delp[1] = &t->avl_left; /* was &p->avl_left */ |
350 | } | |
351 | peer_avl_rebalance(stack, stackptr); | |
d6cc1d64 | 352 | peers.total--; |
1da177e4 LT |
353 | do_free = 1; |
354 | } | |
aa1039e7 | 355 | spin_unlock_bh(&peers.lock); |
1da177e4 LT |
356 | |
357 | if (do_free) | |
aa1039e7 | 358 | call_rcu_bh(&p->rcu, inetpeer_free_rcu); |
1da177e4 LT |
359 | else |
360 | /* The node is used again. Decrease the reference counter | |
361 | * back. The loop "cleanup -> unlink_from_unused | |
362 | * -> unlink_from_pool -> putpeer -> link_to_unused | |
363 | * -> cleanup (for the same node)" | |
364 | * doesn't really exist because the entry will have a | |
aa1039e7 ED |
365 | * recent deletion time and will not be cleaned again soon. |
366 | */ | |
1da177e4 LT |
367 | inet_putpeer(p); |
368 | } | |
369 | ||
370 | /* May be called with local BH enabled. */ | |
371 | static int cleanup_once(unsigned long ttl) | |
372 | { | |
d71209de | 373 | struct inet_peer *p = NULL; |
1da177e4 LT |
374 | |
375 | /* Remove the first entry from the list of unused nodes. */ | |
d6cc1d64 ED |
376 | spin_lock_bh(&unused_peers.lock); |
377 | if (!list_empty(&unused_peers.list)) { | |
d71209de PE |
378 | __u32 delta; |
379 | ||
d6cc1d64 | 380 | p = list_first_entry(&unused_peers.list, struct inet_peer, unused); |
d71209de PE |
381 | delta = (__u32)jiffies - p->dtime; |
382 | ||
4663afe2 | 383 | if (delta < ttl) { |
1da177e4 | 384 | /* Do not prune fresh entries. */ |
d6cc1d64 | 385 | spin_unlock_bh(&unused_peers.lock); |
1da177e4 LT |
386 | return -1; |
387 | } | |
d71209de PE |
388 | |
389 | list_del_init(&p->unused); | |
390 | ||
1da177e4 LT |
391 | /* Grab an extra reference to prevent node disappearing |
392 | * before unlink_from_pool() call. */ | |
393 | atomic_inc(&p->refcnt); | |
394 | } | |
d6cc1d64 | 395 | spin_unlock_bh(&unused_peers.lock); |
1da177e4 LT |
396 | |
397 | if (p == NULL) | |
398 | /* It means that the total number of USED entries has | |
399 | * grown over inet_peer_threshold. It shouldn't really | |
400 | * happen because of entry limits in route cache. */ | |
401 | return -1; | |
402 | ||
403 | unlink_from_pool(p); | |
404 | return 0; | |
405 | } | |
406 | ||
407 | /* Called with or without local BH being disabled. */ | |
53576d9b | 408 | struct inet_peer *inet_getpeer(__be32 daddr, int create) |
1da177e4 | 409 | { |
aa1039e7 | 410 | struct inet_peer *p; |
1da177e4 LT |
411 | struct inet_peer **stack[PEER_MAXDEPTH], ***stackptr; |
412 | ||
aa1039e7 ED |
413 | /* Look up for the address quickly, lockless. |
414 | * Because of a concurrent writer, we might not find an existing entry. | |
415 | */ | |
416 | rcu_read_lock_bh(); | |
417 | p = lookup_rcu_bh(daddr); | |
418 | rcu_read_unlock_bh(); | |
419 | ||
420 | if (p) { | |
421 | /* The existing node has been found. | |
422 | * Remove the entry from unused list if it was there. | |
423 | */ | |
424 | unlink_from_unused(p); | |
425 | return p; | |
426 | } | |
1da177e4 | 427 | |
aa1039e7 ED |
428 | /* retry an exact lookup, taking the lock before. |
429 | * At least, nodes should be hot in our cache. | |
430 | */ | |
431 | spin_lock_bh(&peers.lock); | |
432 | p = lookup(daddr, stack); | |
1da177e4 | 433 | if (p != peer_avl_empty) { |
aa1039e7 ED |
434 | atomic_inc(&p->refcnt); |
435 | spin_unlock_bh(&peers.lock); | |
1da177e4 LT |
436 | /* Remove the entry from unused list if it was there. */ |
437 | unlink_from_unused(p); | |
438 | return p; | |
439 | } | |
aa1039e7 ED |
440 | p = create ? kmem_cache_alloc(peer_cachep, GFP_ATOMIC) : NULL; |
441 | if (p) { | |
442 | p->v4daddr = daddr; | |
443 | atomic_set(&p->refcnt, 1); | |
444 | atomic_set(&p->rid, 0); | |
445 | atomic_set(&p->ip_id_count, secure_ip_id(daddr)); | |
446 | p->tcp_ts_stamp = 0; | |
447 | INIT_LIST_HEAD(&p->unused); | |
448 | ||
449 | ||
450 | /* Link the node. */ | |
451 | link_to_pool(p); | |
452 | peers.total++; | |
453 | } | |
454 | spin_unlock_bh(&peers.lock); | |
1da177e4 | 455 | |
d6cc1d64 | 456 | if (peers.total >= inet_peer_threshold) |
1da177e4 LT |
457 | /* Remove one less-recently-used entry. */ |
458 | cleanup_once(0); | |
459 | ||
1da177e4 LT |
460 | return p; |
461 | } | |
462 | ||
463 | /* Called with local BH disabled. */ | |
464 | static void peer_check_expire(unsigned long dummy) | |
465 | { | |
4663afe2 | 466 | unsigned long now = jiffies; |
1da177e4 LT |
467 | int ttl; |
468 | ||
d6cc1d64 | 469 | if (peers.total >= inet_peer_threshold) |
1da177e4 LT |
470 | ttl = inet_peer_minttl; |
471 | else | |
472 | ttl = inet_peer_maxttl | |
473 | - (inet_peer_maxttl - inet_peer_minttl) / HZ * | |
d6cc1d64 | 474 | peers.total / inet_peer_threshold * HZ; |
4663afe2 ED |
475 | while (!cleanup_once(ttl)) { |
476 | if (jiffies != now) | |
477 | break; | |
478 | } | |
1da177e4 LT |
479 | |
480 | /* Trigger the timer after inet_peer_gc_mintime .. inet_peer_gc_maxtime | |
481 | * interval depending on the total number of entries (more entries, | |
482 | * less interval). */ | |
d6cc1d64 | 483 | if (peers.total >= inet_peer_threshold) |
1344a416 DJ |
484 | peer_periodic_timer.expires = jiffies + inet_peer_gc_mintime; |
485 | else | |
486 | peer_periodic_timer.expires = jiffies | |
487 | + inet_peer_gc_maxtime | |
488 | - (inet_peer_gc_maxtime - inet_peer_gc_mintime) / HZ * | |
d6cc1d64 | 489 | peers.total / inet_peer_threshold * HZ; |
1da177e4 LT |
490 | add_timer(&peer_periodic_timer); |
491 | } | |
4663afe2 ED |
492 | |
493 | void inet_putpeer(struct inet_peer *p) | |
494 | { | |
d6cc1d64 ED |
495 | local_bh_disable(); |
496 | ||
497 | if (atomic_dec_and_lock(&p->refcnt, &unused_peers.lock)) { | |
498 | list_add_tail(&p->unused, &unused_peers.list); | |
4663afe2 | 499 | p->dtime = (__u32)jiffies; |
d6cc1d64 | 500 | spin_unlock(&unused_peers.lock); |
4663afe2 | 501 | } |
d6cc1d64 ED |
502 | |
503 | local_bh_enable(); | |
4663afe2 | 504 | } |