This source file includes following definitions.
- flow_offload_fill_dir
- flow_offload_alloc
- flow_offload_fixup_tcp
- nf_flow_timeout_delta
- flow_offload_fixup_ct_timeout
- flow_offload_fixup_ct_state
- flow_offload_fixup_ct
- flow_offload_free
- flow_offload_hash
- flow_offload_hash_obj
- flow_offload_hash_cmp
- flow_offload_add
- nf_flow_has_expired
- flow_offload_del
- flow_offload_teardown
- flow_offload_lookup
- nf_flow_table_iterate
- nf_flow_offload_gc_step
- nf_flow_offload_work_gc
- nf_flow_nat_port_tcp
- nf_flow_nat_port_udp
- nf_flow_nat_port
- nf_flow_snat_port
- nf_flow_dnat_port
- nf_flow_table_init
- nf_flow_table_do_cleanup
- nf_flow_table_iterate_cleanup
- nf_flow_table_cleanup
- nf_flow_table_free
1
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/netfilter.h>
6 #include <linux/rhashtable.h>
7 #include <linux/netdevice.h>
8 #include <net/ip.h>
9 #include <net/ip6_route.h>
10 #include <net/netfilter/nf_tables.h>
11 #include <net/netfilter/nf_flow_table.h>
12 #include <net/netfilter/nf_conntrack.h>
13 #include <net/netfilter/nf_conntrack_core.h>
14 #include <net/netfilter/nf_conntrack_l4proto.h>
15 #include <net/netfilter/nf_conntrack_tuple.h>
16
17 struct flow_offload_entry {
18 struct flow_offload flow;
19 struct nf_conn *ct;
20 struct rcu_head rcu_head;
21 };
22
23 static DEFINE_MUTEX(flowtable_lock);
24 static LIST_HEAD(flowtables);
25
26 static void
27 flow_offload_fill_dir(struct flow_offload *flow, struct nf_conn *ct,
28 struct nf_flow_route *route,
29 enum flow_offload_tuple_dir dir)
30 {
31 struct flow_offload_tuple *ft = &flow->tuplehash[dir].tuple;
32 struct nf_conntrack_tuple *ctt = &ct->tuplehash[dir].tuple;
33 struct dst_entry *other_dst = route->tuple[!dir].dst;
34 struct dst_entry *dst = route->tuple[dir].dst;
35
36 ft->dir = dir;
37
38 switch (ctt->src.l3num) {
39 case NFPROTO_IPV4:
40 ft->src_v4 = ctt->src.u3.in;
41 ft->dst_v4 = ctt->dst.u3.in;
42 ft->mtu = ip_dst_mtu_maybe_forward(dst, true);
43 break;
44 case NFPROTO_IPV6:
45 ft->src_v6 = ctt->src.u3.in6;
46 ft->dst_v6 = ctt->dst.u3.in6;
47 ft->mtu = ip6_dst_mtu_forward(dst);
48 break;
49 }
50
51 ft->l3proto = ctt->src.l3num;
52 ft->l4proto = ctt->dst.protonum;
53 ft->src_port = ctt->src.u.tcp.port;
54 ft->dst_port = ctt->dst.u.tcp.port;
55
56 ft->iifidx = other_dst->dev->ifindex;
57 ft->dst_cache = dst;
58 }
59
60 struct flow_offload *
61 flow_offload_alloc(struct nf_conn *ct, struct nf_flow_route *route)
62 {
63 struct flow_offload_entry *entry;
64 struct flow_offload *flow;
65
66 if (unlikely(nf_ct_is_dying(ct) ||
67 !atomic_inc_not_zero(&ct->ct_general.use)))
68 return NULL;
69
70 entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
71 if (!entry)
72 goto err_ct_refcnt;
73
74 flow = &entry->flow;
75
76 if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst))
77 goto err_dst_cache_original;
78
79 if (!dst_hold_safe(route->tuple[FLOW_OFFLOAD_DIR_REPLY].dst))
80 goto err_dst_cache_reply;
81
82 entry->ct = ct;
83
84 flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_ORIGINAL);
85 flow_offload_fill_dir(flow, ct, route, FLOW_OFFLOAD_DIR_REPLY);
86
87 if (ct->status & IPS_SRC_NAT)
88 flow->flags |= FLOW_OFFLOAD_SNAT;
89 if (ct->status & IPS_DST_NAT)
90 flow->flags |= FLOW_OFFLOAD_DNAT;
91
92 return flow;
93
94 err_dst_cache_reply:
95 dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst);
96 err_dst_cache_original:
97 kfree(entry);
98 err_ct_refcnt:
99 nf_ct_put(ct);
100
101 return NULL;
102 }
103 EXPORT_SYMBOL_GPL(flow_offload_alloc);
104
105 static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
106 {
107 tcp->state = TCP_CONNTRACK_ESTABLISHED;
108 tcp->seen[0].td_maxwin = 0;
109 tcp->seen[1].td_maxwin = 0;
110 }
111
112 #define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT (120 * HZ)
113 #define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT (30 * HZ)
114
115 static inline __s32 nf_flow_timeout_delta(unsigned int timeout)
116 {
117 return (__s32)(timeout - (u32)jiffies);
118 }
119
120 static void flow_offload_fixup_ct_timeout(struct nf_conn *ct)
121 {
122 const struct nf_conntrack_l4proto *l4proto;
123 int l4num = nf_ct_protonum(ct);
124 unsigned int timeout;
125
126 l4proto = nf_ct_l4proto_find(l4num);
127 if (!l4proto)
128 return;
129
130 if (l4num == IPPROTO_TCP)
131 timeout = NF_FLOWTABLE_TCP_PICKUP_TIMEOUT;
132 else if (l4num == IPPROTO_UDP)
133 timeout = NF_FLOWTABLE_UDP_PICKUP_TIMEOUT;
134 else
135 return;
136
137 if (nf_flow_timeout_delta(ct->timeout) > (__s32)timeout)
138 ct->timeout = nfct_time_stamp + timeout;
139 }
140
141 static void flow_offload_fixup_ct_state(struct nf_conn *ct)
142 {
143 if (nf_ct_protonum(ct) == IPPROTO_TCP)
144 flow_offload_fixup_tcp(&ct->proto.tcp);
145 }
146
147 static void flow_offload_fixup_ct(struct nf_conn *ct)
148 {
149 flow_offload_fixup_ct_state(ct);
150 flow_offload_fixup_ct_timeout(ct);
151 }
152
153 void flow_offload_free(struct flow_offload *flow)
154 {
155 struct flow_offload_entry *e;
156
157 dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
158 dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
159 e = container_of(flow, struct flow_offload_entry, flow);
160 if (flow->flags & FLOW_OFFLOAD_DYING)
161 nf_ct_delete(e->ct, 0, 0);
162 nf_ct_put(e->ct);
163 kfree_rcu(e, rcu_head);
164 }
165 EXPORT_SYMBOL_GPL(flow_offload_free);
166
167 static u32 flow_offload_hash(const void *data, u32 len, u32 seed)
168 {
169 const struct flow_offload_tuple *tuple = data;
170
171 return jhash(tuple, offsetof(struct flow_offload_tuple, dir), seed);
172 }
173
174 static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
175 {
176 const struct flow_offload_tuple_rhash *tuplehash = data;
177
178 return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, dir), seed);
179 }
180
181 static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
182 const void *ptr)
183 {
184 const struct flow_offload_tuple *tuple = arg->key;
185 const struct flow_offload_tuple_rhash *x = ptr;
186
187 if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, dir)))
188 return 1;
189
190 return 0;
191 }
192
193 static const struct rhashtable_params nf_flow_offload_rhash_params = {
194 .head_offset = offsetof(struct flow_offload_tuple_rhash, node),
195 .hashfn = flow_offload_hash,
196 .obj_hashfn = flow_offload_hash_obj,
197 .obj_cmpfn = flow_offload_hash_cmp,
198 .automatic_shrinking = true,
199 };
200
201 int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
202 {
203 int err;
204
205 flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
206
207 err = rhashtable_insert_fast(&flow_table->rhashtable,
208 &flow->tuplehash[0].node,
209 nf_flow_offload_rhash_params);
210 if (err < 0)
211 return err;
212
213 err = rhashtable_insert_fast(&flow_table->rhashtable,
214 &flow->tuplehash[1].node,
215 nf_flow_offload_rhash_params);
216 if (err < 0) {
217 rhashtable_remove_fast(&flow_table->rhashtable,
218 &flow->tuplehash[0].node,
219 nf_flow_offload_rhash_params);
220 return err;
221 }
222
223 return 0;
224 }
225 EXPORT_SYMBOL_GPL(flow_offload_add);
226
227 static inline bool nf_flow_has_expired(const struct flow_offload *flow)
228 {
229 return nf_flow_timeout_delta(flow->timeout) <= 0;
230 }
231
232 static void flow_offload_del(struct nf_flowtable *flow_table,
233 struct flow_offload *flow)
234 {
235 struct flow_offload_entry *e;
236
237 rhashtable_remove_fast(&flow_table->rhashtable,
238 &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
239 nf_flow_offload_rhash_params);
240 rhashtable_remove_fast(&flow_table->rhashtable,
241 &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
242 nf_flow_offload_rhash_params);
243
244 e = container_of(flow, struct flow_offload_entry, flow);
245 clear_bit(IPS_OFFLOAD_BIT, &e->ct->status);
246
247 if (nf_flow_has_expired(flow))
248 flow_offload_fixup_ct(e->ct);
249 else if (flow->flags & FLOW_OFFLOAD_TEARDOWN)
250 flow_offload_fixup_ct_timeout(e->ct);
251
252 flow_offload_free(flow);
253 }
254
255 void flow_offload_teardown(struct flow_offload *flow)
256 {
257 struct flow_offload_entry *e;
258
259 flow->flags |= FLOW_OFFLOAD_TEARDOWN;
260
261 e = container_of(flow, struct flow_offload_entry, flow);
262 flow_offload_fixup_ct_state(e->ct);
263 }
264 EXPORT_SYMBOL_GPL(flow_offload_teardown);
265
266 struct flow_offload_tuple_rhash *
267 flow_offload_lookup(struct nf_flowtable *flow_table,
268 struct flow_offload_tuple *tuple)
269 {
270 struct flow_offload_tuple_rhash *tuplehash;
271 struct flow_offload *flow;
272 struct flow_offload_entry *e;
273 int dir;
274
275 tuplehash = rhashtable_lookup(&flow_table->rhashtable, tuple,
276 nf_flow_offload_rhash_params);
277 if (!tuplehash)
278 return NULL;
279
280 dir = tuplehash->tuple.dir;
281 flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
282 if (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN))
283 return NULL;
284
285 e = container_of(flow, struct flow_offload_entry, flow);
286 if (unlikely(nf_ct_is_dying(e->ct)))
287 return NULL;
288
289 return tuplehash;
290 }
291 EXPORT_SYMBOL_GPL(flow_offload_lookup);
292
293 static int
294 nf_flow_table_iterate(struct nf_flowtable *flow_table,
295 void (*iter)(struct flow_offload *flow, void *data),
296 void *data)
297 {
298 struct flow_offload_tuple_rhash *tuplehash;
299 struct rhashtable_iter hti;
300 struct flow_offload *flow;
301 int err = 0;
302
303 rhashtable_walk_enter(&flow_table->rhashtable, &hti);
304 rhashtable_walk_start(&hti);
305
306 while ((tuplehash = rhashtable_walk_next(&hti))) {
307 if (IS_ERR(tuplehash)) {
308 if (PTR_ERR(tuplehash) != -EAGAIN) {
309 err = PTR_ERR(tuplehash);
310 break;
311 }
312 continue;
313 }
314 if (tuplehash->tuple.dir)
315 continue;
316
317 flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
318
319 iter(flow, data);
320 }
321 rhashtable_walk_stop(&hti);
322 rhashtable_walk_exit(&hti);
323
324 return err;
325 }
326
327 static void nf_flow_offload_gc_step(struct flow_offload *flow, void *data)
328 {
329 struct nf_flowtable *flow_table = data;
330 struct flow_offload_entry *e;
331
332 e = container_of(flow, struct flow_offload_entry, flow);
333 if (nf_flow_has_expired(flow) || nf_ct_is_dying(e->ct) ||
334 (flow->flags & (FLOW_OFFLOAD_DYING | FLOW_OFFLOAD_TEARDOWN)))
335 flow_offload_del(flow_table, flow);
336 }
337
338 static void nf_flow_offload_work_gc(struct work_struct *work)
339 {
340 struct nf_flowtable *flow_table;
341
342 flow_table = container_of(work, struct nf_flowtable, gc_work.work);
343 nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
344 queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
345 }
346
347 static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
348 __be16 port, __be16 new_port)
349 {
350 struct tcphdr *tcph;
351
352 if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
353 skb_try_make_writable(skb, thoff + sizeof(*tcph)))
354 return -1;
355
356 tcph = (void *)(skb_network_header(skb) + thoff);
357 inet_proto_csum_replace2(&tcph->check, skb, port, new_port, true);
358
359 return 0;
360 }
361
362 static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
363 __be16 port, __be16 new_port)
364 {
365 struct udphdr *udph;
366
367 if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
368 skb_try_make_writable(skb, thoff + sizeof(*udph)))
369 return -1;
370
371 udph = (void *)(skb_network_header(skb) + thoff);
372 if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
373 inet_proto_csum_replace2(&udph->check, skb, port,
374 new_port, true);
375 if (!udph->check)
376 udph->check = CSUM_MANGLED_0;
377 }
378
379 return 0;
380 }
381
382 static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
383 u8 protocol, __be16 port, __be16 new_port)
384 {
385 switch (protocol) {
386 case IPPROTO_TCP:
387 if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0)
388 return NF_DROP;
389 break;
390 case IPPROTO_UDP:
391 if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0)
392 return NF_DROP;
393 break;
394 }
395
396 return 0;
397 }
398
399 int nf_flow_snat_port(const struct flow_offload *flow,
400 struct sk_buff *skb, unsigned int thoff,
401 u8 protocol, enum flow_offload_tuple_dir dir)
402 {
403 struct flow_ports *hdr;
404 __be16 port, new_port;
405
406 if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
407 skb_try_make_writable(skb, thoff + sizeof(*hdr)))
408 return -1;
409
410 hdr = (void *)(skb_network_header(skb) + thoff);
411
412 switch (dir) {
413 case FLOW_OFFLOAD_DIR_ORIGINAL:
414 port = hdr->source;
415 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
416 hdr->source = new_port;
417 break;
418 case FLOW_OFFLOAD_DIR_REPLY:
419 port = hdr->dest;
420 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
421 hdr->dest = new_port;
422 break;
423 default:
424 return -1;
425 }
426
427 return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
428 }
429 EXPORT_SYMBOL_GPL(nf_flow_snat_port);
430
431 int nf_flow_dnat_port(const struct flow_offload *flow,
432 struct sk_buff *skb, unsigned int thoff,
433 u8 protocol, enum flow_offload_tuple_dir dir)
434 {
435 struct flow_ports *hdr;
436 __be16 port, new_port;
437
438 if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
439 skb_try_make_writable(skb, thoff + sizeof(*hdr)))
440 return -1;
441
442 hdr = (void *)(skb_network_header(skb) + thoff);
443
444 switch (dir) {
445 case FLOW_OFFLOAD_DIR_ORIGINAL:
446 port = hdr->dest;
447 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port;
448 hdr->dest = new_port;
449 break;
450 case FLOW_OFFLOAD_DIR_REPLY:
451 port = hdr->source;
452 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port;
453 hdr->source = new_port;
454 break;
455 default:
456 return -1;
457 }
458
459 return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
460 }
461 EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
462
463 int nf_flow_table_init(struct nf_flowtable *flowtable)
464 {
465 int err;
466
467 INIT_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
468
469 err = rhashtable_init(&flowtable->rhashtable,
470 &nf_flow_offload_rhash_params);
471 if (err < 0)
472 return err;
473
474 queue_delayed_work(system_power_efficient_wq,
475 &flowtable->gc_work, HZ);
476
477 mutex_lock(&flowtable_lock);
478 list_add(&flowtable->list, &flowtables);
479 mutex_unlock(&flowtable_lock);
480
481 return 0;
482 }
483 EXPORT_SYMBOL_GPL(nf_flow_table_init);
484
485 static void nf_flow_table_do_cleanup(struct flow_offload *flow, void *data)
486 {
487 struct net_device *dev = data;
488 struct flow_offload_entry *e;
489
490 e = container_of(flow, struct flow_offload_entry, flow);
491
492 if (!dev) {
493 flow_offload_teardown(flow);
494 return;
495 }
496 if (net_eq(nf_ct_net(e->ct), dev_net(dev)) &&
497 (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
498 flow->tuplehash[1].tuple.iifidx == dev->ifindex))
499 flow_offload_dead(flow);
500 }
501
502 static void nf_flow_table_iterate_cleanup(struct nf_flowtable *flowtable,
503 struct net_device *dev)
504 {
505 nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
506 flush_delayed_work(&flowtable->gc_work);
507 }
508
509 void nf_flow_table_cleanup(struct net_device *dev)
510 {
511 struct nf_flowtable *flowtable;
512
513 mutex_lock(&flowtable_lock);
514 list_for_each_entry(flowtable, &flowtables, list)
515 nf_flow_table_iterate_cleanup(flowtable, dev);
516 mutex_unlock(&flowtable_lock);
517 }
518 EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
519
520 void nf_flow_table_free(struct nf_flowtable *flow_table)
521 {
522 mutex_lock(&flowtable_lock);
523 list_del(&flow_table->list);
524 mutex_unlock(&flowtable_lock);
525 cancel_delayed_work_sync(&flow_table->gc_work);
526 nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
527 nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
528 rhashtable_destroy(&flow_table->rhashtable);
529 }
530 EXPORT_SYMBOL_GPL(nf_flow_table_free);
531
532 MODULE_LICENSE("GPL");
533 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");