xref: /linux/net/openvswitch/conntrack.c (revision daaa7d647f81f3f1494d9a9029d611b666d63181)
1 /*
2  * Copyright (c) 2015 Nicira, Inc.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of version 2 of the GNU General Public
6  * License as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful, but
9  * WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11  * General Public License for more details.
12  */
13 
14 #include <linux/module.h>
15 #include <linux/openvswitch.h>
16 #include <net/ip.h>
17 #include <net/netfilter/nf_conntrack_core.h>
18 #include <net/netfilter/nf_conntrack_helper.h>
19 #include <net/netfilter/nf_conntrack_labels.h>
20 #include <net/netfilter/nf_conntrack_zones.h>
21 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
22 
23 #include "datapath.h"
24 #include "conntrack.h"
25 #include "flow.h"
26 #include "flow_netlink.h"
27 
28 struct ovs_ct_len_tbl {
29 	size_t maxlen;
30 	size_t minlen;
31 };
32 
33 /* Metadata mark for masked write to conntrack mark */
34 struct md_mark {
35 	u32 value;
36 	u32 mask;
37 };
38 
39 /* Metadata label for masked write to conntrack label. */
40 struct md_labels {
41 	struct ovs_key_ct_labels value;
42 	struct ovs_key_ct_labels mask;
43 };
44 
45 /* Conntrack action context for execution. */
46 struct ovs_conntrack_info {
47 	struct nf_conntrack_helper *helper;
48 	struct nf_conntrack_zone zone;
49 	struct nf_conn *ct;
50 	u8 commit : 1;
51 	u16 family;
52 	struct md_mark mark;
53 	struct md_labels labels;
54 };
55 
56 static u16 key_to_nfproto(const struct sw_flow_key *key)
57 {
58 	switch (ntohs(key->eth.type)) {
59 	case ETH_P_IP:
60 		return NFPROTO_IPV4;
61 	case ETH_P_IPV6:
62 		return NFPROTO_IPV6;
63 	default:
64 		return NFPROTO_UNSPEC;
65 	}
66 }
67 
68 /* Map SKB connection state into the values used by flow definition. */
69 static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo)
70 {
71 	u8 ct_state = OVS_CS_F_TRACKED;
72 
73 	switch (ctinfo) {
74 	case IP_CT_ESTABLISHED_REPLY:
75 	case IP_CT_RELATED_REPLY:
76 	case IP_CT_NEW_REPLY:
77 		ct_state |= OVS_CS_F_REPLY_DIR;
78 		break;
79 	default:
80 		break;
81 	}
82 
83 	switch (ctinfo) {
84 	case IP_CT_ESTABLISHED:
85 	case IP_CT_ESTABLISHED_REPLY:
86 		ct_state |= OVS_CS_F_ESTABLISHED;
87 		break;
88 	case IP_CT_RELATED:
89 	case IP_CT_RELATED_REPLY:
90 		ct_state |= OVS_CS_F_RELATED;
91 		break;
92 	case IP_CT_NEW:
93 	case IP_CT_NEW_REPLY:
94 		ct_state |= OVS_CS_F_NEW;
95 		break;
96 	default:
97 		break;
98 	}
99 
100 	return ct_state;
101 }
102 
103 static u32 ovs_ct_get_mark(const struct nf_conn *ct)
104 {
105 #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
106 	return ct ? ct->mark : 0;
107 #else
108 	return 0;
109 #endif
110 }
111 
112 static void ovs_ct_get_labels(const struct nf_conn *ct,
113 			      struct ovs_key_ct_labels *labels)
114 {
115 	struct nf_conn_labels *cl = ct ? nf_ct_labels_find(ct) : NULL;
116 
117 	if (cl) {
118 		size_t len = cl->words * sizeof(long);
119 
120 		if (len > OVS_CT_LABELS_LEN)
121 			len = OVS_CT_LABELS_LEN;
122 		else if (len < OVS_CT_LABELS_LEN)
123 			memset(labels, 0, OVS_CT_LABELS_LEN);
124 		memcpy(labels, cl->bits, len);
125 	} else {
126 		memset(labels, 0, OVS_CT_LABELS_LEN);
127 	}
128 }
129 
130 static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state,
131 				const struct nf_conntrack_zone *zone,
132 				const struct nf_conn *ct)
133 {
134 	key->ct.state = state;
135 	key->ct.zone = zone->id;
136 	key->ct.mark = ovs_ct_get_mark(ct);
137 	ovs_ct_get_labels(ct, &key->ct.labels);
138 }
139 
140 /* Update 'key' based on skb->nfct. If 'post_ct' is true, then OVS has
141  * previously sent the packet to conntrack via the ct action.
142  */
143 static void ovs_ct_update_key(const struct sk_buff *skb,
144 			      struct sw_flow_key *key, bool post_ct)
145 {
146 	const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
147 	enum ip_conntrack_info ctinfo;
148 	struct nf_conn *ct;
149 	u8 state = 0;
150 
151 	ct = nf_ct_get(skb, &ctinfo);
152 	if (ct) {
153 		state = ovs_ct_get_state(ctinfo);
154 		if (!nf_ct_is_confirmed(ct))
155 			state |= OVS_CS_F_NEW;
156 		if (ct->master)
157 			state |= OVS_CS_F_RELATED;
158 		zone = nf_ct_zone(ct);
159 	} else if (post_ct) {
160 		state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID;
161 	}
162 	__ovs_ct_update_key(key, state, zone, ct);
163 }
164 
165 void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key)
166 {
167 	ovs_ct_update_key(skb, key, false);
168 }
169 
170 int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb)
171 {
172 	if (nla_put_u32(skb, OVS_KEY_ATTR_CT_STATE, key->ct.state))
173 		return -EMSGSIZE;
174 
175 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
176 	    nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, key->ct.zone))
177 		return -EMSGSIZE;
178 
179 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
180 	    nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, key->ct.mark))
181 		return -EMSGSIZE;
182 
183 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
184 	    nla_put(skb, OVS_KEY_ATTR_CT_LABELS, sizeof(key->ct.labels),
185 		    &key->ct.labels))
186 		return -EMSGSIZE;
187 
188 	return 0;
189 }
190 
191 static int ovs_ct_set_mark(struct sk_buff *skb, struct sw_flow_key *key,
192 			   u32 ct_mark, u32 mask)
193 {
194 #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
195 	enum ip_conntrack_info ctinfo;
196 	struct nf_conn *ct;
197 	u32 new_mark;
198 
199 
200 	/* The connection could be invalid, in which case set_mark is no-op. */
201 	ct = nf_ct_get(skb, &ctinfo);
202 	if (!ct)
203 		return 0;
204 
205 	new_mark = ct_mark | (ct->mark & ~(mask));
206 	if (ct->mark != new_mark) {
207 		ct->mark = new_mark;
208 		nf_conntrack_event_cache(IPCT_MARK, ct);
209 		key->ct.mark = new_mark;
210 	}
211 
212 	return 0;
213 #else
214 	return -ENOTSUPP;
215 #endif
216 }
217 
218 static int ovs_ct_set_labels(struct sk_buff *skb, struct sw_flow_key *key,
219 			     const struct ovs_key_ct_labels *labels,
220 			     const struct ovs_key_ct_labels *mask)
221 {
222 	enum ip_conntrack_info ctinfo;
223 	struct nf_conn_labels *cl;
224 	struct nf_conn *ct;
225 	int err;
226 
227 	/* The connection could be invalid, in which case set_label is no-op.*/
228 	ct = nf_ct_get(skb, &ctinfo);
229 	if (!ct)
230 		return 0;
231 
232 	cl = nf_ct_labels_find(ct);
233 	if (!cl) {
234 		nf_ct_labels_ext_add(ct);
235 		cl = nf_ct_labels_find(ct);
236 	}
237 	if (!cl || cl->words * sizeof(long) < OVS_CT_LABELS_LEN)
238 		return -ENOSPC;
239 
240 	err = nf_connlabels_replace(ct, (u32 *)labels, (u32 *)mask,
241 				    OVS_CT_LABELS_LEN / sizeof(u32));
242 	if (err)
243 		return err;
244 
245 	ovs_ct_get_labels(ct, &key->ct.labels);
246 	return 0;
247 }
248 
249 /* 'skb' should already be pulled to nh_ofs. */
250 static int ovs_ct_helper(struct sk_buff *skb, u16 proto)
251 {
252 	const struct nf_conntrack_helper *helper;
253 	const struct nf_conn_help *help;
254 	enum ip_conntrack_info ctinfo;
255 	unsigned int protoff;
256 	struct nf_conn *ct;
257 
258 	ct = nf_ct_get(skb, &ctinfo);
259 	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
260 		return NF_ACCEPT;
261 
262 	help = nfct_help(ct);
263 	if (!help)
264 		return NF_ACCEPT;
265 
266 	helper = rcu_dereference(help->helper);
267 	if (!helper)
268 		return NF_ACCEPT;
269 
270 	switch (proto) {
271 	case NFPROTO_IPV4:
272 		protoff = ip_hdrlen(skb);
273 		break;
274 	case NFPROTO_IPV6: {
275 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
276 		__be16 frag_off;
277 		int ofs;
278 
279 		ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
280 				       &frag_off);
281 		if (ofs < 0 || (frag_off & htons(~0x7)) != 0) {
282 			pr_debug("proto header not found\n");
283 			return NF_ACCEPT;
284 		}
285 		protoff = ofs;
286 		break;
287 	}
288 	default:
289 		WARN_ONCE(1, "helper invoked on non-IP family!");
290 		return NF_DROP;
291 	}
292 
293 	return helper->help(skb, protoff, ct, ctinfo);
294 }
295 
296 /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
297  * value if 'skb' is freed.
298  */
299 static int handle_fragments(struct net *net, struct sw_flow_key *key,
300 			    u16 zone, struct sk_buff *skb)
301 {
302 	struct ovs_skb_cb ovs_cb = *OVS_CB(skb);
303 	int err;
304 
305 	if (key->eth.type == htons(ETH_P_IP)) {
306 		enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
307 
308 		memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
309 		err = ip_defrag(net, skb, user);
310 		if (err)
311 			return err;
312 
313 		ovs_cb.mru = IPCB(skb)->frag_max_size;
314 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
315 	} else if (key->eth.type == htons(ETH_P_IPV6)) {
316 		enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
317 
318 		memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
319 		err = nf_ct_frag6_gather(net, skb, user);
320 		if (err)
321 			return err;
322 
323 		key->ip.proto = ipv6_hdr(skb)->nexthdr;
324 		ovs_cb.mru = IP6CB(skb)->frag_max_size;
325 #endif
326 	} else {
327 		kfree_skb(skb);
328 		return -EPFNOSUPPORT;
329 	}
330 
331 	key->ip.frag = OVS_FRAG_TYPE_NONE;
332 	skb_clear_hash(skb);
333 	skb->ignore_df = 1;
334 	*OVS_CB(skb) = ovs_cb;
335 
336 	return 0;
337 }
338 
339 static struct nf_conntrack_expect *
340 ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone,
341 		   u16 proto, const struct sk_buff *skb)
342 {
343 	struct nf_conntrack_tuple tuple;
344 
345 	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, net, &tuple))
346 		return NULL;
347 	return __nf_ct_expect_find(net, zone, &tuple);
348 }
349 
350 /* Determine whether skb->nfct is equal to the result of conntrack lookup. */
351 static bool skb_nfct_cached(const struct net *net, const struct sk_buff *skb,
352 			    const struct ovs_conntrack_info *info)
353 {
354 	enum ip_conntrack_info ctinfo;
355 	struct nf_conn *ct;
356 
357 	ct = nf_ct_get(skb, &ctinfo);
358 	if (!ct)
359 		return false;
360 	if (!net_eq(net, read_pnet(&ct->ct_net)))
361 		return false;
362 	if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct)))
363 		return false;
364 	if (info->helper) {
365 		struct nf_conn_help *help;
366 
367 		help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
368 		if (help && rcu_access_pointer(help->helper) != info->helper)
369 			return false;
370 	}
371 
372 	return true;
373 }
374 
375 static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
376 			   const struct ovs_conntrack_info *info,
377 			   struct sk_buff *skb)
378 {
379 	/* If we are recirculating packets to match on conntrack fields and
380 	 * committing with a separate conntrack action,  then we don't need to
381 	 * actually run the packet through conntrack twice unless it's for a
382 	 * different zone.
383 	 */
384 	if (!skb_nfct_cached(net, skb, info)) {
385 		struct nf_conn *tmpl = info->ct;
386 
387 		/* Associate skb with specified zone. */
388 		if (tmpl) {
389 			if (skb->nfct)
390 				nf_conntrack_put(skb->nfct);
391 			nf_conntrack_get(&tmpl->ct_general);
392 			skb->nfct = &tmpl->ct_general;
393 			skb->nfctinfo = IP_CT_NEW;
394 		}
395 
396 		if (nf_conntrack_in(net, info->family, NF_INET_PRE_ROUTING,
397 				    skb) != NF_ACCEPT)
398 			return -ENOENT;
399 
400 		if (ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
401 			WARN_ONCE(1, "helper rejected packet");
402 			return -EINVAL;
403 		}
404 	}
405 
406 	ovs_ct_update_key(skb, key, true);
407 
408 	return 0;
409 }
410 
411 /* Lookup connection and read fields into key. */
412 static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
413 			 const struct ovs_conntrack_info *info,
414 			 struct sk_buff *skb)
415 {
416 	struct nf_conntrack_expect *exp;
417 
418 	exp = ovs_ct_expect_find(net, &info->zone, info->family, skb);
419 	if (exp) {
420 		u8 state;
421 
422 		state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED;
423 		__ovs_ct_update_key(key, state, &info->zone, exp->master);
424 	} else {
425 		int err;
426 
427 		err = __ovs_ct_lookup(net, key, info, skb);
428 		if (err)
429 			return err;
430 	}
431 
432 	return 0;
433 }
434 
435 /* Lookup connection and confirm if unconfirmed. */
436 static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
437 			 const struct ovs_conntrack_info *info,
438 			 struct sk_buff *skb)
439 {
440 	u8 state;
441 	int err;
442 
443 	state = key->ct.state;
444 	if (key->ct.zone == info->zone.id &&
445 	    ((state & OVS_CS_F_TRACKED) && !(state & OVS_CS_F_NEW))) {
446 		/* Previous lookup has shown that this connection is already
447 		 * tracked and committed. Skip committing.
448 		 */
449 		return 0;
450 	}
451 
452 	err = __ovs_ct_lookup(net, key, info, skb);
453 	if (err)
454 		return err;
455 	if (nf_conntrack_confirm(skb) != NF_ACCEPT)
456 		return -EINVAL;
457 
458 	return 0;
459 }
460 
461 static bool labels_nonzero(const struct ovs_key_ct_labels *labels)
462 {
463 	size_t i;
464 
465 	for (i = 0; i < sizeof(*labels); i++)
466 		if (labels->ct_labels[i])
467 			return true;
468 
469 	return false;
470 }
471 
472 /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
473  * value if 'skb' is freed.
474  */
475 int ovs_ct_execute(struct net *net, struct sk_buff *skb,
476 		   struct sw_flow_key *key,
477 		   const struct ovs_conntrack_info *info)
478 {
479 	int nh_ofs;
480 	int err;
481 
482 	/* The conntrack module expects to be working at L3. */
483 	nh_ofs = skb_network_offset(skb);
484 	skb_pull(skb, nh_ofs);
485 
486 	if (key->ip.frag != OVS_FRAG_TYPE_NONE) {
487 		err = handle_fragments(net, key, info->zone.id, skb);
488 		if (err)
489 			return err;
490 	}
491 
492 	if (info->commit)
493 		err = ovs_ct_commit(net, key, info, skb);
494 	else
495 		err = ovs_ct_lookup(net, key, info, skb);
496 	if (err)
497 		goto err;
498 
499 	if (info->mark.mask) {
500 		err = ovs_ct_set_mark(skb, key, info->mark.value,
501 				      info->mark.mask);
502 		if (err)
503 			goto err;
504 	}
505 	if (labels_nonzero(&info->labels.mask))
506 		err = ovs_ct_set_labels(skb, key, &info->labels.value,
507 					&info->labels.mask);
508 err:
509 	skb_push(skb, nh_ofs);
510 	if (err)
511 		kfree_skb(skb);
512 	return err;
513 }
514 
515 static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name,
516 			     const struct sw_flow_key *key, bool log)
517 {
518 	struct nf_conntrack_helper *helper;
519 	struct nf_conn_help *help;
520 
521 	helper = nf_conntrack_helper_try_module_get(name, info->family,
522 						    key->ip.proto);
523 	if (!helper) {
524 		OVS_NLERR(log, "Unknown helper \"%s\"", name);
525 		return -EINVAL;
526 	}
527 
528 	help = nf_ct_helper_ext_add(info->ct, helper, GFP_KERNEL);
529 	if (!help) {
530 		module_put(helper->me);
531 		return -ENOMEM;
532 	}
533 
534 	rcu_assign_pointer(help->helper, helper);
535 	info->helper = helper;
536 	return 0;
537 }
538 
539 static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = {
540 	[OVS_CT_ATTR_COMMIT]	= { .minlen = 0, .maxlen = 0 },
541 	[OVS_CT_ATTR_ZONE]	= { .minlen = sizeof(u16),
542 				    .maxlen = sizeof(u16) },
543 	[OVS_CT_ATTR_MARK]	= { .minlen = sizeof(struct md_mark),
544 				    .maxlen = sizeof(struct md_mark) },
545 	[OVS_CT_ATTR_LABELS]	= { .minlen = sizeof(struct md_labels),
546 				    .maxlen = sizeof(struct md_labels) },
547 	[OVS_CT_ATTR_HELPER]	= { .minlen = 1,
548 				    .maxlen = NF_CT_HELPER_NAME_LEN }
549 };
550 
551 static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
552 		    const char **helper, bool log)
553 {
554 	struct nlattr *a;
555 	int rem;
556 
557 	nla_for_each_nested(a, attr, rem) {
558 		int type = nla_type(a);
559 		int maxlen = ovs_ct_attr_lens[type].maxlen;
560 		int minlen = ovs_ct_attr_lens[type].minlen;
561 
562 		if (type > OVS_CT_ATTR_MAX) {
563 			OVS_NLERR(log,
564 				  "Unknown conntrack attr (type=%d, max=%d)",
565 				  type, OVS_CT_ATTR_MAX);
566 			return -EINVAL;
567 		}
568 		if (nla_len(a) < minlen || nla_len(a) > maxlen) {
569 			OVS_NLERR(log,
570 				  "Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)",
571 				  type, nla_len(a), maxlen);
572 			return -EINVAL;
573 		}
574 
575 		switch (type) {
576 		case OVS_CT_ATTR_COMMIT:
577 			info->commit = true;
578 			break;
579 #ifdef CONFIG_NF_CONNTRACK_ZONES
580 		case OVS_CT_ATTR_ZONE:
581 			info->zone.id = nla_get_u16(a);
582 			break;
583 #endif
584 #ifdef CONFIG_NF_CONNTRACK_MARK
585 		case OVS_CT_ATTR_MARK: {
586 			struct md_mark *mark = nla_data(a);
587 
588 			if (!mark->mask) {
589 				OVS_NLERR(log, "ct_mark mask cannot be 0");
590 				return -EINVAL;
591 			}
592 			info->mark = *mark;
593 			break;
594 		}
595 #endif
596 #ifdef CONFIG_NF_CONNTRACK_LABELS
597 		case OVS_CT_ATTR_LABELS: {
598 			struct md_labels *labels = nla_data(a);
599 
600 			if (!labels_nonzero(&labels->mask)) {
601 				OVS_NLERR(log, "ct_labels mask cannot be 0");
602 				return -EINVAL;
603 			}
604 			info->labels = *labels;
605 			break;
606 		}
607 #endif
608 		case OVS_CT_ATTR_HELPER:
609 			*helper = nla_data(a);
610 			if (!memchr(*helper, '\0', nla_len(a))) {
611 				OVS_NLERR(log, "Invalid conntrack helper");
612 				return -EINVAL;
613 			}
614 			break;
615 		default:
616 			OVS_NLERR(log, "Unknown conntrack attr (%d)",
617 				  type);
618 			return -EINVAL;
619 		}
620 	}
621 
622 	if (rem > 0) {
623 		OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem);
624 		return -EINVAL;
625 	}
626 
627 	return 0;
628 }
629 
630 bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
631 {
632 	if (attr == OVS_KEY_ATTR_CT_STATE)
633 		return true;
634 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
635 	    attr == OVS_KEY_ATTR_CT_ZONE)
636 		return true;
637 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
638 	    attr == OVS_KEY_ATTR_CT_MARK)
639 		return true;
640 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
641 	    attr == OVS_KEY_ATTR_CT_LABELS) {
642 		struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
643 
644 		return ovs_net->xt_label;
645 	}
646 
647 	return false;
648 }
649 
650 int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
651 		       const struct sw_flow_key *key,
652 		       struct sw_flow_actions **sfa,  bool log)
653 {
654 	struct ovs_conntrack_info ct_info;
655 	const char *helper = NULL;
656 	u16 family;
657 	int err;
658 
659 	family = key_to_nfproto(key);
660 	if (family == NFPROTO_UNSPEC) {
661 		OVS_NLERR(log, "ct family unspecified");
662 		return -EINVAL;
663 	}
664 
665 	memset(&ct_info, 0, sizeof(ct_info));
666 	ct_info.family = family;
667 
668 	nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID,
669 			NF_CT_DEFAULT_ZONE_DIR, 0);
670 
671 	err = parse_ct(attr, &ct_info, &helper, log);
672 	if (err)
673 		return err;
674 
675 	/* Set up template for tracking connections in specific zones. */
676 	ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL);
677 	if (!ct_info.ct) {
678 		OVS_NLERR(log, "Failed to allocate conntrack template");
679 		return -ENOMEM;
680 	}
681 	if (helper) {
682 		err = ovs_ct_add_helper(&ct_info, helper, key, log);
683 		if (err)
684 			goto err_free_ct;
685 	}
686 
687 	err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info,
688 				 sizeof(ct_info), log);
689 	if (err)
690 		goto err_free_ct;
691 
692 	__set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status);
693 	nf_conntrack_get(&ct_info.ct->ct_general);
694 	return 0;
695 err_free_ct:
696 	nf_conntrack_free(ct_info.ct);
697 	return err;
698 }
699 
700 int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info,
701 			  struct sk_buff *skb)
702 {
703 	struct nlattr *start;
704 
705 	start = nla_nest_start(skb, OVS_ACTION_ATTR_CT);
706 	if (!start)
707 		return -EMSGSIZE;
708 
709 	if (ct_info->commit && nla_put_flag(skb, OVS_CT_ATTR_COMMIT))
710 		return -EMSGSIZE;
711 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
712 	    nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id))
713 		return -EMSGSIZE;
714 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && ct_info->mark.mask &&
715 	    nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark),
716 		    &ct_info->mark))
717 		return -EMSGSIZE;
718 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
719 	    labels_nonzero(&ct_info->labels.mask) &&
720 	    nla_put(skb, OVS_CT_ATTR_LABELS, sizeof(ct_info->labels),
721 		    &ct_info->labels))
722 		return -EMSGSIZE;
723 	if (ct_info->helper) {
724 		if (nla_put_string(skb, OVS_CT_ATTR_HELPER,
725 				   ct_info->helper->name))
726 			return -EMSGSIZE;
727 	}
728 
729 	nla_nest_end(skb, start);
730 
731 	return 0;
732 }
733 
734 void ovs_ct_free_action(const struct nlattr *a)
735 {
736 	struct ovs_conntrack_info *ct_info = nla_data(a);
737 
738 	if (ct_info->helper)
739 		module_put(ct_info->helper->me);
740 	if (ct_info->ct)
741 		nf_ct_put(ct_info->ct);
742 }
743 
744 void ovs_ct_init(struct net *net)
745 {
746 	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
747 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
748 
749 	if (nf_connlabels_get(net, n_bits)) {
750 		ovs_net->xt_label = false;
751 		OVS_NLERR(true, "Failed to set connlabel length");
752 	} else {
753 		ovs_net->xt_label = true;
754 	}
755 }
756 
757 void ovs_ct_exit(struct net *net)
758 {
759 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
760 
761 	if (ovs_net->xt_label)
762 		nf_connlabels_put(net);
763 }
764