xref: /openbmc/linux/net/openvswitch/conntrack.c (revision 8b235f2f)
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_label {
41 	struct ovs_key_ct_label value;
42 	struct ovs_key_ct_label 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 	u32 flags;
51 	u16 family;
52 	struct md_mark mark;
53 	struct md_label label;
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_label(const struct nf_conn *ct,
113 			     struct ovs_key_ct_label *label)
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_LABEL_LEN)
121 			len = OVS_CT_LABEL_LEN;
122 		else if (len < OVS_CT_LABEL_LEN)
123 			memset(label, 0, OVS_CT_LABEL_LEN);
124 		memcpy(label, cl->bits, len);
125 	} else {
126 		memset(label, 0, OVS_CT_LABEL_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_label(ct, &key->ct.label);
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 (ct->master)
155 			state |= OVS_CS_F_RELATED;
156 		zone = nf_ct_zone(ct);
157 	} else if (post_ct) {
158 		state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID;
159 	}
160 	__ovs_ct_update_key(key, state, zone, ct);
161 }
162 
163 void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key)
164 {
165 	ovs_ct_update_key(skb, key, false);
166 }
167 
168 int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb)
169 {
170 	if (nla_put_u8(skb, OVS_KEY_ATTR_CT_STATE, key->ct.state))
171 		return -EMSGSIZE;
172 
173 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
174 	    nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, key->ct.zone))
175 		return -EMSGSIZE;
176 
177 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
178 	    nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, key->ct.mark))
179 		return -EMSGSIZE;
180 
181 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
182 	    nla_put(skb, OVS_KEY_ATTR_CT_LABEL, sizeof(key->ct.label),
183 		    &key->ct.label))
184 		return -EMSGSIZE;
185 
186 	return 0;
187 }
188 
189 static int ovs_ct_set_mark(struct sk_buff *skb, struct sw_flow_key *key,
190 			   u32 ct_mark, u32 mask)
191 {
192 #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
193 	enum ip_conntrack_info ctinfo;
194 	struct nf_conn *ct;
195 	u32 new_mark;
196 
197 
198 	/* The connection could be invalid, in which case set_mark is no-op. */
199 	ct = nf_ct_get(skb, &ctinfo);
200 	if (!ct)
201 		return 0;
202 
203 	new_mark = ct_mark | (ct->mark & ~(mask));
204 	if (ct->mark != new_mark) {
205 		ct->mark = new_mark;
206 		nf_conntrack_event_cache(IPCT_MARK, ct);
207 		key->ct.mark = new_mark;
208 	}
209 
210 	return 0;
211 #else
212 	return -ENOTSUPP;
213 #endif
214 }
215 
216 static int ovs_ct_set_label(struct sk_buff *skb, struct sw_flow_key *key,
217 			    const struct ovs_key_ct_label *label,
218 			    const struct ovs_key_ct_label *mask)
219 {
220 	enum ip_conntrack_info ctinfo;
221 	struct nf_conn_labels *cl;
222 	struct nf_conn *ct;
223 	int err;
224 
225 	if (!IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS))
226 		return -ENOTSUPP;
227 
228 	/* The connection could be invalid, in which case set_label is no-op.*/
229 	ct = nf_ct_get(skb, &ctinfo);
230 	if (!ct)
231 		return 0;
232 
233 	cl = nf_ct_labels_find(ct);
234 	if (!cl) {
235 		nf_ct_labels_ext_add(ct);
236 		cl = nf_ct_labels_find(ct);
237 	}
238 	if (!cl || cl->words * sizeof(long) < OVS_CT_LABEL_LEN)
239 		return -ENOSPC;
240 
241 	err = nf_connlabels_replace(ct, (u32 *)label, (u32 *)mask,
242 				    OVS_CT_LABEL_LEN / sizeof(u32));
243 	if (err)
244 		return err;
245 
246 	ovs_ct_get_label(ct, &key->ct.label);
247 	return 0;
248 }
249 
250 /* 'skb' should already be pulled to nh_ofs. */
251 static int ovs_ct_helper(struct sk_buff *skb, u16 proto)
252 {
253 	const struct nf_conntrack_helper *helper;
254 	const struct nf_conn_help *help;
255 	enum ip_conntrack_info ctinfo;
256 	unsigned int protoff;
257 	struct nf_conn *ct;
258 
259 	ct = nf_ct_get(skb, &ctinfo);
260 	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
261 		return NF_ACCEPT;
262 
263 	help = nfct_help(ct);
264 	if (!help)
265 		return NF_ACCEPT;
266 
267 	helper = rcu_dereference(help->helper);
268 	if (!helper)
269 		return NF_ACCEPT;
270 
271 	switch (proto) {
272 	case NFPROTO_IPV4:
273 		protoff = ip_hdrlen(skb);
274 		break;
275 	case NFPROTO_IPV6: {
276 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
277 		__be16 frag_off;
278 
279 		protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
280 					   &nexthdr, &frag_off);
281 		if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
282 			pr_debug("proto header not found\n");
283 			return NF_ACCEPT;
284 		}
285 		break;
286 	}
287 	default:
288 		WARN_ONCE(1, "helper invoked on non-IP family!");
289 		return NF_DROP;
290 	}
291 
292 	return helper->help(skb, protoff, ct, ctinfo);
293 }
294 
295 static int handle_fragments(struct net *net, struct sw_flow_key *key,
296 			    u16 zone, struct sk_buff *skb)
297 {
298 	struct ovs_skb_cb ovs_cb = *OVS_CB(skb);
299 
300 	if (key->eth.type == htons(ETH_P_IP)) {
301 		enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
302 		int err;
303 
304 		memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
305 		err = ip_defrag(skb, user);
306 		if (err)
307 			return err;
308 
309 		ovs_cb.mru = IPCB(skb)->frag_max_size;
310 	} else if (key->eth.type == htons(ETH_P_IPV6)) {
311 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
312 		enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
313 		struct sk_buff *reasm;
314 
315 		memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
316 		reasm = nf_ct_frag6_gather(skb, user);
317 		if (!reasm)
318 			return -EINPROGRESS;
319 
320 		if (skb == reasm)
321 			return -EINVAL;
322 
323 		key->ip.proto = ipv6_hdr(reasm)->nexthdr;
324 		skb_morph(skb, reasm);
325 		consume_skb(reasm);
326 		ovs_cb.mru = IP6CB(skb)->frag_max_size;
327 #else
328 		return -EPFNOSUPPORT;
329 #endif
330 	} else {
331 		return -EPFNOSUPPORT;
332 	}
333 
334 	key->ip.frag = OVS_FRAG_TYPE_NONE;
335 	skb_clear_hash(skb);
336 	skb->ignore_df = 1;
337 	*OVS_CB(skb) = ovs_cb;
338 
339 	return 0;
340 }
341 
342 static struct nf_conntrack_expect *
343 ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone,
344 		   u16 proto, const struct sk_buff *skb)
345 {
346 	struct nf_conntrack_tuple tuple;
347 
348 	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, &tuple))
349 		return NULL;
350 	return __nf_ct_expect_find(net, zone, &tuple);
351 }
352 
353 /* Determine whether skb->nfct is equal to the result of conntrack lookup. */
354 static bool skb_nfct_cached(const struct net *net, const struct sk_buff *skb,
355 			    const struct ovs_conntrack_info *info)
356 {
357 	enum ip_conntrack_info ctinfo;
358 	struct nf_conn *ct;
359 
360 	ct = nf_ct_get(skb, &ctinfo);
361 	if (!ct)
362 		return false;
363 	if (!net_eq(net, read_pnet(&ct->ct_net)))
364 		return false;
365 	if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct)))
366 		return false;
367 	if (info->helper) {
368 		struct nf_conn_help *help;
369 
370 		help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
371 		if (help && rcu_access_pointer(help->helper) != info->helper)
372 			return false;
373 	}
374 
375 	return true;
376 }
377 
378 static int __ovs_ct_lookup(struct net *net, const struct sw_flow_key *key,
379 			   const struct ovs_conntrack_info *info,
380 			   struct sk_buff *skb)
381 {
382 	/* If we are recirculating packets to match on conntrack fields and
383 	 * committing with a separate conntrack action,  then we don't need to
384 	 * actually run the packet through conntrack twice unless it's for a
385 	 * different zone.
386 	 */
387 	if (!skb_nfct_cached(net, skb, info)) {
388 		struct nf_conn *tmpl = info->ct;
389 
390 		/* Associate skb with specified zone. */
391 		if (tmpl) {
392 			if (skb->nfct)
393 				nf_conntrack_put(skb->nfct);
394 			nf_conntrack_get(&tmpl->ct_general);
395 			skb->nfct = &tmpl->ct_general;
396 			skb->nfctinfo = IP_CT_NEW;
397 		}
398 
399 		if (nf_conntrack_in(net, info->family, NF_INET_PRE_ROUTING,
400 				    skb) != NF_ACCEPT)
401 			return -ENOENT;
402 
403 		if (ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
404 			WARN_ONCE(1, "helper rejected packet");
405 			return -EINVAL;
406 		}
407 	}
408 
409 	return 0;
410 }
411 
412 /* Lookup connection and read fields into key. */
413 static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
414 			 const struct ovs_conntrack_info *info,
415 			 struct sk_buff *skb)
416 {
417 	struct nf_conntrack_expect *exp;
418 
419 	exp = ovs_ct_expect_find(net, &info->zone, info->family, skb);
420 	if (exp) {
421 		u8 state;
422 
423 		state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED;
424 		__ovs_ct_update_key(key, state, &info->zone, exp->master);
425 	} else {
426 		int err;
427 
428 		err = __ovs_ct_lookup(net, key, info, skb);
429 		if (err)
430 			return err;
431 
432 		ovs_ct_update_key(skb, key, true);
433 	}
434 
435 	return 0;
436 }
437 
438 /* Lookup connection and confirm if unconfirmed. */
439 static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
440 			 const struct ovs_conntrack_info *info,
441 			 struct sk_buff *skb)
442 {
443 	u8 state;
444 	int err;
445 
446 	state = key->ct.state;
447 	if (key->ct.zone == info->zone.id &&
448 	    ((state & OVS_CS_F_TRACKED) && !(state & OVS_CS_F_NEW))) {
449 		/* Previous lookup has shown that this connection is already
450 		 * tracked and committed. Skip committing.
451 		 */
452 		return 0;
453 	}
454 
455 	err = __ovs_ct_lookup(net, key, info, skb);
456 	if (err)
457 		return err;
458 	if (nf_conntrack_confirm(skb) != NF_ACCEPT)
459 		return -EINVAL;
460 
461 	ovs_ct_update_key(skb, key, true);
462 
463 	return 0;
464 }
465 
466 static bool label_nonzero(const struct ovs_key_ct_label *label)
467 {
468 	size_t i;
469 
470 	for (i = 0; i < sizeof(*label); i++)
471 		if (label->ct_label[i])
472 			return true;
473 
474 	return false;
475 }
476 
477 int ovs_ct_execute(struct net *net, struct sk_buff *skb,
478 		   struct sw_flow_key *key,
479 		   const struct ovs_conntrack_info *info)
480 {
481 	int nh_ofs;
482 	int err;
483 
484 	/* The conntrack module expects to be working at L3. */
485 	nh_ofs = skb_network_offset(skb);
486 	skb_pull(skb, nh_ofs);
487 
488 	if (key->ip.frag != OVS_FRAG_TYPE_NONE) {
489 		err = handle_fragments(net, key, info->zone.id, skb);
490 		if (err)
491 			return err;
492 	}
493 
494 	if (info->flags & OVS_CT_F_COMMIT)
495 		err = ovs_ct_commit(net, key, info, skb);
496 	else
497 		err = ovs_ct_lookup(net, key, info, skb);
498 	if (err)
499 		goto err;
500 
501 	if (info->mark.mask) {
502 		err = ovs_ct_set_mark(skb, key, info->mark.value,
503 				      info->mark.mask);
504 		if (err)
505 			goto err;
506 	}
507 	if (label_nonzero(&info->label.mask))
508 		err = ovs_ct_set_label(skb, key, &info->label.value,
509 				       &info->label.mask);
510 err:
511 	skb_push(skb, nh_ofs);
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_FLAGS]	= { .minlen = sizeof(u32),
541 				    .maxlen = sizeof(u32) },
542 	[OVS_CT_ATTR_ZONE]	= { .minlen = sizeof(u16),
543 				    .maxlen = sizeof(u16) },
544 	[OVS_CT_ATTR_MARK]	= { .minlen = sizeof(struct md_mark),
545 				    .maxlen = sizeof(struct md_mark) },
546 	[OVS_CT_ATTR_LABEL]	= { .minlen = sizeof(struct md_label),
547 				    .maxlen = sizeof(struct md_label) },
548 	[OVS_CT_ATTR_HELPER]	= { .minlen = 1,
549 				    .maxlen = NF_CT_HELPER_NAME_LEN }
550 };
551 
552 static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
553 		    const char **helper, bool log)
554 {
555 	struct nlattr *a;
556 	int rem;
557 
558 	nla_for_each_nested(a, attr, rem) {
559 		int type = nla_type(a);
560 		int maxlen = ovs_ct_attr_lens[type].maxlen;
561 		int minlen = ovs_ct_attr_lens[type].minlen;
562 
563 		if (type > OVS_CT_ATTR_MAX) {
564 			OVS_NLERR(log,
565 				  "Unknown conntrack attr (type=%d, max=%d)",
566 				  type, OVS_CT_ATTR_MAX);
567 			return -EINVAL;
568 		}
569 		if (nla_len(a) < minlen || nla_len(a) > maxlen) {
570 			OVS_NLERR(log,
571 				  "Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)",
572 				  type, nla_len(a), maxlen);
573 			return -EINVAL;
574 		}
575 
576 		switch (type) {
577 		case OVS_CT_ATTR_FLAGS:
578 			info->flags = nla_get_u32(a);
579 			break;
580 #ifdef CONFIG_NF_CONNTRACK_ZONES
581 		case OVS_CT_ATTR_ZONE:
582 			info->zone.id = nla_get_u16(a);
583 			break;
584 #endif
585 #ifdef CONFIG_NF_CONNTRACK_MARK
586 		case OVS_CT_ATTR_MARK: {
587 			struct md_mark *mark = nla_data(a);
588 
589 			info->mark = *mark;
590 			break;
591 		}
592 #endif
593 #ifdef CONFIG_NF_CONNTRACK_LABELS
594 		case OVS_CT_ATTR_LABEL: {
595 			struct md_label *label = nla_data(a);
596 
597 			info->label = *label;
598 			break;
599 		}
600 #endif
601 		case OVS_CT_ATTR_HELPER:
602 			*helper = nla_data(a);
603 			if (!memchr(*helper, '\0', nla_len(a))) {
604 				OVS_NLERR(log, "Invalid conntrack helper");
605 				return -EINVAL;
606 			}
607 			break;
608 		default:
609 			OVS_NLERR(log, "Unknown conntrack attr (%d)",
610 				  type);
611 			return -EINVAL;
612 		}
613 	}
614 
615 	if (rem > 0) {
616 		OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem);
617 		return -EINVAL;
618 	}
619 
620 	return 0;
621 }
622 
623 bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
624 {
625 	if (attr == OVS_KEY_ATTR_CT_STATE)
626 		return true;
627 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
628 	    attr == OVS_KEY_ATTR_CT_ZONE)
629 		return true;
630 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
631 	    attr == OVS_KEY_ATTR_CT_MARK)
632 		return true;
633 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
634 	    attr == OVS_KEY_ATTR_CT_LABEL) {
635 		struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
636 
637 		return ovs_net->xt_label;
638 	}
639 
640 	return false;
641 }
642 
643 int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
644 		       const struct sw_flow_key *key,
645 		       struct sw_flow_actions **sfa,  bool log)
646 {
647 	struct ovs_conntrack_info ct_info;
648 	const char *helper = NULL;
649 	u16 family;
650 	int err;
651 
652 	family = key_to_nfproto(key);
653 	if (family == NFPROTO_UNSPEC) {
654 		OVS_NLERR(log, "ct family unspecified");
655 		return -EINVAL;
656 	}
657 
658 	memset(&ct_info, 0, sizeof(ct_info));
659 	ct_info.family = family;
660 
661 	nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID,
662 			NF_CT_DEFAULT_ZONE_DIR, 0);
663 
664 	err = parse_ct(attr, &ct_info, &helper, log);
665 	if (err)
666 		return err;
667 
668 	/* Set up template for tracking connections in specific zones. */
669 	ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL);
670 	if (!ct_info.ct) {
671 		OVS_NLERR(log, "Failed to allocate conntrack template");
672 		return -ENOMEM;
673 	}
674 	if (helper) {
675 		err = ovs_ct_add_helper(&ct_info, helper, key, log);
676 		if (err)
677 			goto err_free_ct;
678 	}
679 
680 	err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info,
681 				 sizeof(ct_info), log);
682 	if (err)
683 		goto err_free_ct;
684 
685 	__set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status);
686 	nf_conntrack_get(&ct_info.ct->ct_general);
687 	return 0;
688 err_free_ct:
689 	nf_conntrack_free(ct_info.ct);
690 	return err;
691 }
692 
693 int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info,
694 			  struct sk_buff *skb)
695 {
696 	struct nlattr *start;
697 
698 	start = nla_nest_start(skb, OVS_ACTION_ATTR_CT);
699 	if (!start)
700 		return -EMSGSIZE;
701 
702 	if (nla_put_u32(skb, OVS_CT_ATTR_FLAGS, ct_info->flags))
703 		return -EMSGSIZE;
704 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
705 	    nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id))
706 		return -EMSGSIZE;
707 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
708 	    nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark),
709 		    &ct_info->mark))
710 		return -EMSGSIZE;
711 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
712 	    nla_put(skb, OVS_CT_ATTR_LABEL, sizeof(ct_info->label),
713 		    &ct_info->label))
714 		return -EMSGSIZE;
715 	if (ct_info->helper) {
716 		if (nla_put_string(skb, OVS_CT_ATTR_HELPER,
717 				   ct_info->helper->name))
718 			return -EMSGSIZE;
719 	}
720 
721 	nla_nest_end(skb, start);
722 
723 	return 0;
724 }
725 
726 void ovs_ct_free_action(const struct nlattr *a)
727 {
728 	struct ovs_conntrack_info *ct_info = nla_data(a);
729 
730 	if (ct_info->helper)
731 		module_put(ct_info->helper->me);
732 	if (ct_info->ct)
733 		nf_ct_put(ct_info->ct);
734 }
735 
736 void ovs_ct_init(struct net *net)
737 {
738 	unsigned int n_bits = sizeof(struct ovs_key_ct_label) * BITS_PER_BYTE;
739 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
740 
741 	if (nf_connlabels_get(net, n_bits)) {
742 		ovs_net->xt_label = false;
743 		OVS_NLERR(true, "Failed to set connlabel length");
744 	} else {
745 		ovs_net->xt_label = true;
746 	}
747 }
748 
749 void ovs_ct_exit(struct net *net)
750 {
751 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
752 
753 	if (ovs_net->xt_label)
754 		nf_connlabels_put(net);
755 }
756