1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * (C) 1999-2001 Paul `Rusty' Russell
4  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
5  * (C) 2011 Patrick McHardy <kaber@trash.net>
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/module.h>
11 #include <linux/types.h>
12 #include <linux/timer.h>
13 #include <linux/skbuff.h>
14 #include <linux/gfp.h>
15 #include <net/xfrm.h>
16 #include <linux/siphash.h>
17 #include <linux/rtnetlink.h>
18 
19 #include <net/netfilter/nf_conntrack_bpf.h>
20 #include <net/netfilter/nf_conntrack_core.h>
21 #include <net/netfilter/nf_conntrack_helper.h>
22 #include <net/netfilter/nf_conntrack_seqadj.h>
23 #include <net/netfilter/nf_conntrack_zones.h>
24 #include <net/netfilter/nf_nat.h>
25 #include <net/netfilter/nf_nat_helper.h>
26 #include <uapi/linux/netfilter/nf_nat.h>
27 
28 #include "nf_internals.h"
29 
30 static spinlock_t nf_nat_locks[CONNTRACK_LOCKS];
31 
32 static DEFINE_MUTEX(nf_nat_proto_mutex);
33 static unsigned int nat_net_id __read_mostly;
34 
35 static struct hlist_head *nf_nat_bysource __read_mostly;
36 static unsigned int nf_nat_htable_size __read_mostly;
37 static siphash_aligned_key_t nf_nat_hash_rnd;
38 
39 struct nf_nat_lookup_hook_priv {
40 	struct nf_hook_entries __rcu *entries;
41 
42 	struct rcu_head rcu_head;
43 };
44 
45 struct nf_nat_hooks_net {
46 	struct nf_hook_ops *nat_hook_ops;
47 	unsigned int users;
48 };
49 
50 struct nat_net {
51 	struct nf_nat_hooks_net nat_proto_net[NFPROTO_NUMPROTO];
52 };
53 
54 #ifdef CONFIG_XFRM
nf_nat_ipv4_decode_session(struct sk_buff * skb,const struct nf_conn * ct,enum ip_conntrack_dir dir,unsigned long statusbit,struct flowi * fl)55 static void nf_nat_ipv4_decode_session(struct sk_buff *skb,
56 				       const struct nf_conn *ct,
57 				       enum ip_conntrack_dir dir,
58 				       unsigned long statusbit,
59 				       struct flowi *fl)
60 {
61 	const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple;
62 	struct flowi4 *fl4 = &fl->u.ip4;
63 
64 	if (ct->status & statusbit) {
65 		fl4->daddr = t->dst.u3.ip;
66 		if (t->dst.protonum == IPPROTO_TCP ||
67 		    t->dst.protonum == IPPROTO_UDP ||
68 		    t->dst.protonum == IPPROTO_UDPLITE ||
69 		    t->dst.protonum == IPPROTO_DCCP ||
70 		    t->dst.protonum == IPPROTO_SCTP)
71 			fl4->fl4_dport = t->dst.u.all;
72 	}
73 
74 	statusbit ^= IPS_NAT_MASK;
75 
76 	if (ct->status & statusbit) {
77 		fl4->saddr = t->src.u3.ip;
78 		if (t->dst.protonum == IPPROTO_TCP ||
79 		    t->dst.protonum == IPPROTO_UDP ||
80 		    t->dst.protonum == IPPROTO_UDPLITE ||
81 		    t->dst.protonum == IPPROTO_DCCP ||
82 		    t->dst.protonum == IPPROTO_SCTP)
83 			fl4->fl4_sport = t->src.u.all;
84 	}
85 }
86 
nf_nat_ipv6_decode_session(struct sk_buff * skb,const struct nf_conn * ct,enum ip_conntrack_dir dir,unsigned long statusbit,struct flowi * fl)87 static void nf_nat_ipv6_decode_session(struct sk_buff *skb,
88 				       const struct nf_conn *ct,
89 				       enum ip_conntrack_dir dir,
90 				       unsigned long statusbit,
91 				       struct flowi *fl)
92 {
93 #if IS_ENABLED(CONFIG_IPV6)
94 	const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple;
95 	struct flowi6 *fl6 = &fl->u.ip6;
96 
97 	if (ct->status & statusbit) {
98 		fl6->daddr = t->dst.u3.in6;
99 		if (t->dst.protonum == IPPROTO_TCP ||
100 		    t->dst.protonum == IPPROTO_UDP ||
101 		    t->dst.protonum == IPPROTO_UDPLITE ||
102 		    t->dst.protonum == IPPROTO_DCCP ||
103 		    t->dst.protonum == IPPROTO_SCTP)
104 			fl6->fl6_dport = t->dst.u.all;
105 	}
106 
107 	statusbit ^= IPS_NAT_MASK;
108 
109 	if (ct->status & statusbit) {
110 		fl6->saddr = t->src.u3.in6;
111 		if (t->dst.protonum == IPPROTO_TCP ||
112 		    t->dst.protonum == IPPROTO_UDP ||
113 		    t->dst.protonum == IPPROTO_UDPLITE ||
114 		    t->dst.protonum == IPPROTO_DCCP ||
115 		    t->dst.protonum == IPPROTO_SCTP)
116 			fl6->fl6_sport = t->src.u.all;
117 	}
118 #endif
119 }
120 
__nf_nat_decode_session(struct sk_buff * skb,struct flowi * fl)121 static void __nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl)
122 {
123 	const struct nf_conn *ct;
124 	enum ip_conntrack_info ctinfo;
125 	enum ip_conntrack_dir dir;
126 	unsigned  long statusbit;
127 	u8 family;
128 
129 	ct = nf_ct_get(skb, &ctinfo);
130 	if (ct == NULL)
131 		return;
132 
133 	family = nf_ct_l3num(ct);
134 	dir = CTINFO2DIR(ctinfo);
135 	if (dir == IP_CT_DIR_ORIGINAL)
136 		statusbit = IPS_DST_NAT;
137 	else
138 		statusbit = IPS_SRC_NAT;
139 
140 	switch (family) {
141 	case NFPROTO_IPV4:
142 		nf_nat_ipv4_decode_session(skb, ct, dir, statusbit, fl);
143 		return;
144 	case NFPROTO_IPV6:
145 		nf_nat_ipv6_decode_session(skb, ct, dir, statusbit, fl);
146 		return;
147 	}
148 }
149 #endif /* CONFIG_XFRM */
150 
151 /* We keep an extra hash for each conntrack, for fast searching. */
152 static unsigned int
hash_by_src(const struct net * net,const struct nf_conntrack_zone * zone,const struct nf_conntrack_tuple * tuple)153 hash_by_src(const struct net *net,
154 	    const struct nf_conntrack_zone *zone,
155 	    const struct nf_conntrack_tuple *tuple)
156 {
157 	unsigned int hash;
158 	struct {
159 		struct nf_conntrack_man src;
160 		u32 net_mix;
161 		u32 protonum;
162 		u32 zone;
163 	} __aligned(SIPHASH_ALIGNMENT) combined;
164 
165 	get_random_once(&nf_nat_hash_rnd, sizeof(nf_nat_hash_rnd));
166 
167 	memset(&combined, 0, sizeof(combined));
168 
169 	/* Original src, to ensure we map it consistently if poss. */
170 	combined.src = tuple->src;
171 	combined.net_mix = net_hash_mix(net);
172 	combined.protonum = tuple->dst.protonum;
173 
174 	/* Zone ID can be used provided its valid for both directions */
175 	if (zone->dir == NF_CT_DEFAULT_ZONE_DIR)
176 		combined.zone = zone->id;
177 
178 	hash = siphash(&combined, sizeof(combined), &nf_nat_hash_rnd);
179 
180 	return reciprocal_scale(hash, nf_nat_htable_size);
181 }
182 
183 /* Is this tuple already taken? (not by us) */
184 static int
nf_nat_used_tuple(const struct nf_conntrack_tuple * tuple,const struct nf_conn * ignored_conntrack)185 nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
186 		  const struct nf_conn *ignored_conntrack)
187 {
188 	/* Conntrack tracking doesn't keep track of outgoing tuples; only
189 	 * incoming ones.  NAT means they don't have a fixed mapping,
190 	 * so we invert the tuple and look for the incoming reply.
191 	 *
192 	 * We could keep a separate hash if this proves too slow.
193 	 */
194 	struct nf_conntrack_tuple reply;
195 
196 	nf_ct_invert_tuple(&reply, tuple);
197 	return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
198 }
199 
nf_nat_inet_in_range(const struct nf_conntrack_tuple * t,const struct nf_nat_range2 * range)200 static bool nf_nat_inet_in_range(const struct nf_conntrack_tuple *t,
201 				 const struct nf_nat_range2 *range)
202 {
203 	if (t->src.l3num == NFPROTO_IPV4)
204 		return ntohl(t->src.u3.ip) >= ntohl(range->min_addr.ip) &&
205 		       ntohl(t->src.u3.ip) <= ntohl(range->max_addr.ip);
206 
207 	return ipv6_addr_cmp(&t->src.u3.in6, &range->min_addr.in6) >= 0 &&
208 	       ipv6_addr_cmp(&t->src.u3.in6, &range->max_addr.in6) <= 0;
209 }
210 
211 /* Is the manipable part of the tuple between min and max incl? */
l4proto_in_range(const struct nf_conntrack_tuple * tuple,enum nf_nat_manip_type maniptype,const union nf_conntrack_man_proto * min,const union nf_conntrack_man_proto * max)212 static bool l4proto_in_range(const struct nf_conntrack_tuple *tuple,
213 			     enum nf_nat_manip_type maniptype,
214 			     const union nf_conntrack_man_proto *min,
215 			     const union nf_conntrack_man_proto *max)
216 {
217 	__be16 port;
218 
219 	switch (tuple->dst.protonum) {
220 	case IPPROTO_ICMP:
221 	case IPPROTO_ICMPV6:
222 		return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) &&
223 		       ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
224 	case IPPROTO_GRE: /* all fall though */
225 	case IPPROTO_TCP:
226 	case IPPROTO_UDP:
227 	case IPPROTO_UDPLITE:
228 	case IPPROTO_DCCP:
229 	case IPPROTO_SCTP:
230 		if (maniptype == NF_NAT_MANIP_SRC)
231 			port = tuple->src.u.all;
232 		else
233 			port = tuple->dst.u.all;
234 
235 		return ntohs(port) >= ntohs(min->all) &&
236 		       ntohs(port) <= ntohs(max->all);
237 	default:
238 		return true;
239 	}
240 }
241 
242 /* If we source map this tuple so reply looks like reply_tuple, will
243  * that meet the constraints of range.
244  */
in_range(const struct nf_conntrack_tuple * tuple,const struct nf_nat_range2 * range)245 static int in_range(const struct nf_conntrack_tuple *tuple,
246 		    const struct nf_nat_range2 *range)
247 {
248 	/* If we are supposed to map IPs, then we must be in the
249 	 * range specified, otherwise let this drag us onto a new src IP.
250 	 */
251 	if (range->flags & NF_NAT_RANGE_MAP_IPS &&
252 	    !nf_nat_inet_in_range(tuple, range))
253 		return 0;
254 
255 	if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED))
256 		return 1;
257 
258 	return l4proto_in_range(tuple, NF_NAT_MANIP_SRC,
259 				&range->min_proto, &range->max_proto);
260 }
261 
262 static inline int
same_src(const struct nf_conn * ct,const struct nf_conntrack_tuple * tuple)263 same_src(const struct nf_conn *ct,
264 	 const struct nf_conntrack_tuple *tuple)
265 {
266 	const struct nf_conntrack_tuple *t;
267 
268 	t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
269 	return (t->dst.protonum == tuple->dst.protonum &&
270 		nf_inet_addr_cmp(&t->src.u3, &tuple->src.u3) &&
271 		t->src.u.all == tuple->src.u.all);
272 }
273 
274 /* Only called for SRC manip */
275 static int
find_appropriate_src(struct net * net,const struct nf_conntrack_zone * zone,const struct nf_conntrack_tuple * tuple,struct nf_conntrack_tuple * result,const struct nf_nat_range2 * range)276 find_appropriate_src(struct net *net,
277 		     const struct nf_conntrack_zone *zone,
278 		     const struct nf_conntrack_tuple *tuple,
279 		     struct nf_conntrack_tuple *result,
280 		     const struct nf_nat_range2 *range)
281 {
282 	unsigned int h = hash_by_src(net, zone, tuple);
283 	const struct nf_conn *ct;
284 
285 	hlist_for_each_entry_rcu(ct, &nf_nat_bysource[h], nat_bysource) {
286 		if (same_src(ct, tuple) &&
287 		    net_eq(net, nf_ct_net(ct)) &&
288 		    nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) {
289 			/* Copy source part from reply tuple. */
290 			nf_ct_invert_tuple(result,
291 				       &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
292 			result->dst = tuple->dst;
293 
294 			if (in_range(result, range))
295 				return 1;
296 		}
297 	}
298 	return 0;
299 }
300 
301 /* For [FUTURE] fragmentation handling, we want the least-used
302  * src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
303  * if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
304  * 1-65535, we don't do pro-rata allocation based on ports; we choose
305  * the ip with the lowest src-ip/dst-ip/proto usage.
306  */
307 static void
find_best_ips_proto(const struct nf_conntrack_zone * zone,struct nf_conntrack_tuple * tuple,const struct nf_nat_range2 * range,const struct nf_conn * ct,enum nf_nat_manip_type maniptype)308 find_best_ips_proto(const struct nf_conntrack_zone *zone,
309 		    struct nf_conntrack_tuple *tuple,
310 		    const struct nf_nat_range2 *range,
311 		    const struct nf_conn *ct,
312 		    enum nf_nat_manip_type maniptype)
313 {
314 	union nf_inet_addr *var_ipp;
315 	unsigned int i, max;
316 	/* Host order */
317 	u32 minip, maxip, j, dist;
318 	bool full_range;
319 
320 	/* No IP mapping?  Do nothing. */
321 	if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
322 		return;
323 
324 	if (maniptype == NF_NAT_MANIP_SRC)
325 		var_ipp = &tuple->src.u3;
326 	else
327 		var_ipp = &tuple->dst.u3;
328 
329 	/* Fast path: only one choice. */
330 	if (nf_inet_addr_cmp(&range->min_addr, &range->max_addr)) {
331 		*var_ipp = range->min_addr;
332 		return;
333 	}
334 
335 	if (nf_ct_l3num(ct) == NFPROTO_IPV4)
336 		max = sizeof(var_ipp->ip) / sizeof(u32) - 1;
337 	else
338 		max = sizeof(var_ipp->ip6) / sizeof(u32) - 1;
339 
340 	/* Hashing source and destination IPs gives a fairly even
341 	 * spread in practice (if there are a small number of IPs
342 	 * involved, there usually aren't that many connections
343 	 * anyway).  The consistency means that servers see the same
344 	 * client coming from the same IP (some Internet Banking sites
345 	 * like this), even across reboots.
346 	 */
347 	j = jhash2((u32 *)&tuple->src.u3, sizeof(tuple->src.u3) / sizeof(u32),
348 		   range->flags & NF_NAT_RANGE_PERSISTENT ?
349 			0 : (__force u32)tuple->dst.u3.all[max] ^ zone->id);
350 
351 	full_range = false;
352 	for (i = 0; i <= max; i++) {
353 		/* If first bytes of the address are at the maximum, use the
354 		 * distance. Otherwise use the full range.
355 		 */
356 		if (!full_range) {
357 			minip = ntohl((__force __be32)range->min_addr.all[i]);
358 			maxip = ntohl((__force __be32)range->max_addr.all[i]);
359 			dist  = maxip - minip + 1;
360 		} else {
361 			minip = 0;
362 			dist  = ~0;
363 		}
364 
365 		var_ipp->all[i] = (__force __u32)
366 			htonl(minip + reciprocal_scale(j, dist));
367 		if (var_ipp->all[i] != range->max_addr.all[i])
368 			full_range = true;
369 
370 		if (!(range->flags & NF_NAT_RANGE_PERSISTENT))
371 			j ^= (__force u32)tuple->dst.u3.all[i];
372 	}
373 }
374 
375 /* Alter the per-proto part of the tuple (depending on maniptype), to
376  * give a unique tuple in the given range if possible.
377  *
378  * Per-protocol part of tuple is initialized to the incoming packet.
379  */
nf_nat_l4proto_unique_tuple(struct nf_conntrack_tuple * tuple,const struct nf_nat_range2 * range,enum nf_nat_manip_type maniptype,const struct nf_conn * ct)380 static void nf_nat_l4proto_unique_tuple(struct nf_conntrack_tuple *tuple,
381 					const struct nf_nat_range2 *range,
382 					enum nf_nat_manip_type maniptype,
383 					const struct nf_conn *ct)
384 {
385 	unsigned int range_size, min, max, i, attempts;
386 	__be16 *keyptr;
387 	u16 off;
388 	static const unsigned int max_attempts = 128;
389 
390 	switch (tuple->dst.protonum) {
391 	case IPPROTO_ICMP:
392 	case IPPROTO_ICMPV6:
393 		/* id is same for either direction... */
394 		keyptr = &tuple->src.u.icmp.id;
395 		if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
396 			min = 0;
397 			range_size = 65536;
398 		} else {
399 			min = ntohs(range->min_proto.icmp.id);
400 			range_size = ntohs(range->max_proto.icmp.id) -
401 				     ntohs(range->min_proto.icmp.id) + 1;
402 		}
403 		goto find_free_id;
404 #if IS_ENABLED(CONFIG_NF_CT_PROTO_GRE)
405 	case IPPROTO_GRE:
406 		/* If there is no master conntrack we are not PPTP,
407 		   do not change tuples */
408 		if (!ct->master)
409 			return;
410 
411 		if (maniptype == NF_NAT_MANIP_SRC)
412 			keyptr = &tuple->src.u.gre.key;
413 		else
414 			keyptr = &tuple->dst.u.gre.key;
415 
416 		if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
417 			min = 1;
418 			range_size = 65535;
419 		} else {
420 			min = ntohs(range->min_proto.gre.key);
421 			range_size = ntohs(range->max_proto.gre.key) - min + 1;
422 		}
423 		goto find_free_id;
424 #endif
425 	case IPPROTO_UDP:
426 	case IPPROTO_UDPLITE:
427 	case IPPROTO_TCP:
428 	case IPPROTO_SCTP:
429 	case IPPROTO_DCCP:
430 		if (maniptype == NF_NAT_MANIP_SRC)
431 			keyptr = &tuple->src.u.all;
432 		else
433 			keyptr = &tuple->dst.u.all;
434 
435 		break;
436 	default:
437 		return;
438 	}
439 
440 	/* If no range specified... */
441 	if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
442 		/* If it's dst rewrite, can't change port */
443 		if (maniptype == NF_NAT_MANIP_DST)
444 			return;
445 
446 		if (ntohs(*keyptr) < 1024) {
447 			/* Loose convention: >> 512 is credential passing */
448 			if (ntohs(*keyptr) < 512) {
449 				min = 1;
450 				range_size = 511 - min + 1;
451 			} else {
452 				min = 600;
453 				range_size = 1023 - min + 1;
454 			}
455 		} else {
456 			min = 1024;
457 			range_size = 65535 - 1024 + 1;
458 		}
459 	} else {
460 		min = ntohs(range->min_proto.all);
461 		max = ntohs(range->max_proto.all);
462 		if (unlikely(max < min))
463 			swap(max, min);
464 		range_size = max - min + 1;
465 	}
466 
467 find_free_id:
468 	if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
469 		off = (ntohs(*keyptr) - ntohs(range->base_proto.all));
470 	else
471 		off = get_random_u16();
472 
473 	attempts = range_size;
474 	if (attempts > max_attempts)
475 		attempts = max_attempts;
476 
477 	/* We are in softirq; doing a search of the entire range risks
478 	 * soft lockup when all tuples are already used.
479 	 *
480 	 * If we can't find any free port from first offset, pick a new
481 	 * one and try again, with ever smaller search window.
482 	 */
483 another_round:
484 	for (i = 0; i < attempts; i++, off++) {
485 		*keyptr = htons(min + off % range_size);
486 		if (!nf_nat_used_tuple(tuple, ct))
487 			return;
488 	}
489 
490 	if (attempts >= range_size || attempts < 16)
491 		return;
492 	attempts /= 2;
493 	off = get_random_u16();
494 	goto another_round;
495 }
496 
497 /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
498  * we change the source to map into the range. For NF_INET_PRE_ROUTING
499  * and NF_INET_LOCAL_OUT, we change the destination to map into the
500  * range. It might not be possible to get a unique tuple, but we try.
501  * At worst (or if we race), we will end up with a final duplicate in
502  * __nf_conntrack_confirm and drop the packet. */
503 static void
get_unique_tuple(struct nf_conntrack_tuple * tuple,const struct nf_conntrack_tuple * orig_tuple,const struct nf_nat_range2 * range,struct nf_conn * ct,enum nf_nat_manip_type maniptype)504 get_unique_tuple(struct nf_conntrack_tuple *tuple,
505 		 const struct nf_conntrack_tuple *orig_tuple,
506 		 const struct nf_nat_range2 *range,
507 		 struct nf_conn *ct,
508 		 enum nf_nat_manip_type maniptype)
509 {
510 	const struct nf_conntrack_zone *zone;
511 	struct net *net = nf_ct_net(ct);
512 
513 	zone = nf_ct_zone(ct);
514 
515 	/* 1) If this srcip/proto/src-proto-part is currently mapped,
516 	 * and that same mapping gives a unique tuple within the given
517 	 * range, use that.
518 	 *
519 	 * This is only required for source (ie. NAT/masq) mappings.
520 	 * So far, we don't do local source mappings, so multiple
521 	 * manips not an issue.
522 	 */
523 	if (maniptype == NF_NAT_MANIP_SRC &&
524 	    !(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
525 		/* try the original tuple first */
526 		if (in_range(orig_tuple, range)) {
527 			if (!nf_nat_used_tuple(orig_tuple, ct)) {
528 				*tuple = *orig_tuple;
529 				return;
530 			}
531 		} else if (find_appropriate_src(net, zone,
532 						orig_tuple, tuple, range)) {
533 			pr_debug("get_unique_tuple: Found current src map\n");
534 			if (!nf_nat_used_tuple(tuple, ct))
535 				return;
536 		}
537 	}
538 
539 	/* 2) Select the least-used IP/proto combination in the given range */
540 	*tuple = *orig_tuple;
541 	find_best_ips_proto(zone, tuple, range, ct, maniptype);
542 
543 	/* 3) The per-protocol part of the manip is made to map into
544 	 * the range to make a unique tuple.
545 	 */
546 
547 	/* Only bother mapping if it's not already in range and unique */
548 	if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
549 		if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
550 			if (!(range->flags & NF_NAT_RANGE_PROTO_OFFSET) &&
551 			    l4proto_in_range(tuple, maniptype,
552 			          &range->min_proto,
553 			          &range->max_proto) &&
554 			    (range->min_proto.all == range->max_proto.all ||
555 			     !nf_nat_used_tuple(tuple, ct)))
556 				return;
557 		} else if (!nf_nat_used_tuple(tuple, ct)) {
558 			return;
559 		}
560 	}
561 
562 	/* Last chance: get protocol to try to obtain unique tuple. */
563 	nf_nat_l4proto_unique_tuple(tuple, range, maniptype, ct);
564 }
565 
nf_ct_nat_ext_add(struct nf_conn * ct)566 struct nf_conn_nat *nf_ct_nat_ext_add(struct nf_conn *ct)
567 {
568 	struct nf_conn_nat *nat = nfct_nat(ct);
569 	if (nat)
570 		return nat;
571 
572 	if (!nf_ct_is_confirmed(ct))
573 		nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
574 
575 	return nat;
576 }
577 EXPORT_SYMBOL_GPL(nf_ct_nat_ext_add);
578 
579 unsigned int
nf_nat_setup_info(struct nf_conn * ct,const struct nf_nat_range2 * range,enum nf_nat_manip_type maniptype)580 nf_nat_setup_info(struct nf_conn *ct,
581 		  const struct nf_nat_range2 *range,
582 		  enum nf_nat_manip_type maniptype)
583 {
584 	struct net *net = nf_ct_net(ct);
585 	struct nf_conntrack_tuple curr_tuple, new_tuple;
586 
587 	/* Can't setup nat info for confirmed ct. */
588 	if (nf_ct_is_confirmed(ct))
589 		return NF_ACCEPT;
590 
591 	WARN_ON(maniptype != NF_NAT_MANIP_SRC &&
592 		maniptype != NF_NAT_MANIP_DST);
593 
594 	if (WARN_ON(nf_nat_initialized(ct, maniptype)))
595 		return NF_DROP;
596 
597 	/* What we've got will look like inverse of reply. Normally
598 	 * this is what is in the conntrack, except for prior
599 	 * manipulations (future optimization: if num_manips == 0,
600 	 * orig_tp = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
601 	 */
602 	nf_ct_invert_tuple(&curr_tuple,
603 			   &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
604 
605 	get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
606 
607 	if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
608 		struct nf_conntrack_tuple reply;
609 
610 		/* Alter conntrack table so will recognize replies. */
611 		nf_ct_invert_tuple(&reply, &new_tuple);
612 		nf_conntrack_alter_reply(ct, &reply);
613 
614 		/* Non-atomic: we own this at the moment. */
615 		if (maniptype == NF_NAT_MANIP_SRC)
616 			ct->status |= IPS_SRC_NAT;
617 		else
618 			ct->status |= IPS_DST_NAT;
619 
620 		if (nfct_help(ct) && !nfct_seqadj(ct))
621 			if (!nfct_seqadj_ext_add(ct))
622 				return NF_DROP;
623 	}
624 
625 	if (maniptype == NF_NAT_MANIP_SRC) {
626 		unsigned int srchash;
627 		spinlock_t *lock;
628 
629 		srchash = hash_by_src(net, nf_ct_zone(ct),
630 				      &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
631 		lock = &nf_nat_locks[srchash % CONNTRACK_LOCKS];
632 		spin_lock_bh(lock);
633 		hlist_add_head_rcu(&ct->nat_bysource,
634 				   &nf_nat_bysource[srchash]);
635 		spin_unlock_bh(lock);
636 	}
637 
638 	/* It's done. */
639 	if (maniptype == NF_NAT_MANIP_DST)
640 		ct->status |= IPS_DST_NAT_DONE;
641 	else
642 		ct->status |= IPS_SRC_NAT_DONE;
643 
644 	return NF_ACCEPT;
645 }
646 EXPORT_SYMBOL(nf_nat_setup_info);
647 
648 static unsigned int
__nf_nat_alloc_null_binding(struct nf_conn * ct,enum nf_nat_manip_type manip)649 __nf_nat_alloc_null_binding(struct nf_conn *ct, enum nf_nat_manip_type manip)
650 {
651 	/* Force range to this IP; let proto decide mapping for
652 	 * per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
653 	 * Use reply in case it's already been mangled (eg local packet).
654 	 */
655 	union nf_inet_addr ip =
656 		(manip == NF_NAT_MANIP_SRC ?
657 		ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3 :
658 		ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3);
659 	struct nf_nat_range2 range = {
660 		.flags		= NF_NAT_RANGE_MAP_IPS,
661 		.min_addr	= ip,
662 		.max_addr	= ip,
663 	};
664 	return nf_nat_setup_info(ct, &range, manip);
665 }
666 
667 unsigned int
nf_nat_alloc_null_binding(struct nf_conn * ct,unsigned int hooknum)668 nf_nat_alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
669 {
670 	return __nf_nat_alloc_null_binding(ct, HOOK2MANIP(hooknum));
671 }
672 EXPORT_SYMBOL_GPL(nf_nat_alloc_null_binding);
673 
674 /* Do packet manipulations according to nf_nat_setup_info. */
nf_nat_packet(struct nf_conn * ct,enum ip_conntrack_info ctinfo,unsigned int hooknum,struct sk_buff * skb)675 unsigned int nf_nat_packet(struct nf_conn *ct,
676 			   enum ip_conntrack_info ctinfo,
677 			   unsigned int hooknum,
678 			   struct sk_buff *skb)
679 {
680 	enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
681 	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
682 	unsigned int verdict = NF_ACCEPT;
683 	unsigned long statusbit;
684 
685 	if (mtype == NF_NAT_MANIP_SRC)
686 		statusbit = IPS_SRC_NAT;
687 	else
688 		statusbit = IPS_DST_NAT;
689 
690 	/* Invert if this is reply dir. */
691 	if (dir == IP_CT_DIR_REPLY)
692 		statusbit ^= IPS_NAT_MASK;
693 
694 	/* Non-atomic: these bits don't change. */
695 	if (ct->status & statusbit)
696 		verdict = nf_nat_manip_pkt(skb, ct, mtype, dir);
697 
698 	return verdict;
699 }
700 EXPORT_SYMBOL_GPL(nf_nat_packet);
701 
in_vrf_postrouting(const struct nf_hook_state * state)702 static bool in_vrf_postrouting(const struct nf_hook_state *state)
703 {
704 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
705 	if (state->hook == NF_INET_POST_ROUTING &&
706 	    netif_is_l3_master(state->out))
707 		return true;
708 #endif
709 	return false;
710 }
711 
712 unsigned int
nf_nat_inet_fn(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)713 nf_nat_inet_fn(void *priv, struct sk_buff *skb,
714 	       const struct nf_hook_state *state)
715 {
716 	struct nf_conn *ct;
717 	enum ip_conntrack_info ctinfo;
718 	struct nf_conn_nat *nat;
719 	/* maniptype == SRC for postrouting. */
720 	enum nf_nat_manip_type maniptype = HOOK2MANIP(state->hook);
721 
722 	ct = nf_ct_get(skb, &ctinfo);
723 	/* Can't track?  It's not due to stress, or conntrack would
724 	 * have dropped it.  Hence it's the user's responsibilty to
725 	 * packet filter it out, or implement conntrack/NAT for that
726 	 * protocol. 8) --RR
727 	 */
728 	if (!ct || in_vrf_postrouting(state))
729 		return NF_ACCEPT;
730 
731 	nat = nfct_nat(ct);
732 
733 	switch (ctinfo) {
734 	case IP_CT_RELATED:
735 	case IP_CT_RELATED_REPLY:
736 		/* Only ICMPs can be IP_CT_IS_REPLY.  Fallthrough */
737 	case IP_CT_NEW:
738 		/* Seen it before?  This can happen for loopback, retrans,
739 		 * or local packets.
740 		 */
741 		if (!nf_nat_initialized(ct, maniptype)) {
742 			struct nf_nat_lookup_hook_priv *lpriv = priv;
743 			struct nf_hook_entries *e = rcu_dereference(lpriv->entries);
744 			unsigned int ret;
745 			int i;
746 
747 			if (!e)
748 				goto null_bind;
749 
750 			for (i = 0; i < e->num_hook_entries; i++) {
751 				ret = e->hooks[i].hook(e->hooks[i].priv, skb,
752 						       state);
753 				if (ret != NF_ACCEPT)
754 					return ret;
755 				if (nf_nat_initialized(ct, maniptype))
756 					goto do_nat;
757 			}
758 null_bind:
759 			ret = nf_nat_alloc_null_binding(ct, state->hook);
760 			if (ret != NF_ACCEPT)
761 				return ret;
762 		} else {
763 			pr_debug("Already setup manip %s for ct %p (status bits 0x%lx)\n",
764 				 maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
765 				 ct, ct->status);
766 			if (nf_nat_oif_changed(state->hook, ctinfo, nat,
767 					       state->out))
768 				goto oif_changed;
769 		}
770 		break;
771 	default:
772 		/* ESTABLISHED */
773 		WARN_ON(ctinfo != IP_CT_ESTABLISHED &&
774 			ctinfo != IP_CT_ESTABLISHED_REPLY);
775 		if (nf_nat_oif_changed(state->hook, ctinfo, nat, state->out))
776 			goto oif_changed;
777 	}
778 do_nat:
779 	return nf_nat_packet(ct, ctinfo, state->hook, skb);
780 
781 oif_changed:
782 	nf_ct_kill_acct(ct, ctinfo, skb);
783 	return NF_DROP;
784 }
785 EXPORT_SYMBOL_GPL(nf_nat_inet_fn);
786 
787 struct nf_nat_proto_clean {
788 	u8	l3proto;
789 	u8	l4proto;
790 };
791 
792 /* kill conntracks with affected NAT section */
nf_nat_proto_remove(struct nf_conn * i,void * data)793 static int nf_nat_proto_remove(struct nf_conn *i, void *data)
794 {
795 	const struct nf_nat_proto_clean *clean = data;
796 
797 	if ((clean->l3proto && nf_ct_l3num(i) != clean->l3proto) ||
798 	    (clean->l4proto && nf_ct_protonum(i) != clean->l4proto))
799 		return 0;
800 
801 	return i->status & IPS_NAT_MASK ? 1 : 0;
802 }
803 
nf_nat_cleanup_conntrack(struct nf_conn * ct)804 static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
805 {
806 	unsigned int h;
807 
808 	h = hash_by_src(nf_ct_net(ct), nf_ct_zone(ct), &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
809 	spin_lock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
810 	hlist_del_rcu(&ct->nat_bysource);
811 	spin_unlock_bh(&nf_nat_locks[h % CONNTRACK_LOCKS]);
812 }
813 
nf_nat_proto_clean(struct nf_conn * ct,void * data)814 static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
815 {
816 	if (nf_nat_proto_remove(ct, data))
817 		return 1;
818 
819 	/* This module is being removed and conntrack has nat null binding.
820 	 * Remove it from bysource hash, as the table will be freed soon.
821 	 *
822 	 * Else, when the conntrack is destoyed, nf_nat_cleanup_conntrack()
823 	 * will delete entry from already-freed table.
824 	 */
825 	if (test_and_clear_bit(IPS_SRC_NAT_DONE_BIT, &ct->status))
826 		nf_nat_cleanup_conntrack(ct);
827 
828 	/* don't delete conntrack.  Although that would make things a lot
829 	 * simpler, we'd end up flushing all conntracks on nat rmmod.
830 	 */
831 	return 0;
832 }
833 
834 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
835 
836 #include <linux/netfilter/nfnetlink.h>
837 #include <linux/netfilter/nfnetlink_conntrack.h>
838 
839 static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
840 	[CTA_PROTONAT_PORT_MIN]	= { .type = NLA_U16 },
841 	[CTA_PROTONAT_PORT_MAX]	= { .type = NLA_U16 },
842 };
843 
nf_nat_l4proto_nlattr_to_range(struct nlattr * tb[],struct nf_nat_range2 * range)844 static int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
845 					  struct nf_nat_range2 *range)
846 {
847 	if (tb[CTA_PROTONAT_PORT_MIN]) {
848 		range->min_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]);
849 		range->max_proto.all = range->min_proto.all;
850 		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
851 	}
852 	if (tb[CTA_PROTONAT_PORT_MAX]) {
853 		range->max_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]);
854 		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
855 	}
856 	return 0;
857 }
858 
nfnetlink_parse_nat_proto(struct nlattr * attr,const struct nf_conn * ct,struct nf_nat_range2 * range)859 static int nfnetlink_parse_nat_proto(struct nlattr *attr,
860 				     const struct nf_conn *ct,
861 				     struct nf_nat_range2 *range)
862 {
863 	struct nlattr *tb[CTA_PROTONAT_MAX+1];
864 	int err;
865 
866 	err = nla_parse_nested_deprecated(tb, CTA_PROTONAT_MAX, attr,
867 					  protonat_nla_policy, NULL);
868 	if (err < 0)
869 		return err;
870 
871 	return nf_nat_l4proto_nlattr_to_range(tb, range);
872 }
873 
874 static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
875 	[CTA_NAT_V4_MINIP]	= { .type = NLA_U32 },
876 	[CTA_NAT_V4_MAXIP]	= { .type = NLA_U32 },
877 	[CTA_NAT_V6_MINIP]	= { .len = sizeof(struct in6_addr) },
878 	[CTA_NAT_V6_MAXIP]	= { .len = sizeof(struct in6_addr) },
879 	[CTA_NAT_PROTO]		= { .type = NLA_NESTED },
880 };
881 
nf_nat_ipv4_nlattr_to_range(struct nlattr * tb[],struct nf_nat_range2 * range)882 static int nf_nat_ipv4_nlattr_to_range(struct nlattr *tb[],
883 				       struct nf_nat_range2 *range)
884 {
885 	if (tb[CTA_NAT_V4_MINIP]) {
886 		range->min_addr.ip = nla_get_be32(tb[CTA_NAT_V4_MINIP]);
887 		range->flags |= NF_NAT_RANGE_MAP_IPS;
888 	}
889 
890 	if (tb[CTA_NAT_V4_MAXIP])
891 		range->max_addr.ip = nla_get_be32(tb[CTA_NAT_V4_MAXIP]);
892 	else
893 		range->max_addr.ip = range->min_addr.ip;
894 
895 	return 0;
896 }
897 
nf_nat_ipv6_nlattr_to_range(struct nlattr * tb[],struct nf_nat_range2 * range)898 static int nf_nat_ipv6_nlattr_to_range(struct nlattr *tb[],
899 				       struct nf_nat_range2 *range)
900 {
901 	if (tb[CTA_NAT_V6_MINIP]) {
902 		nla_memcpy(&range->min_addr.ip6, tb[CTA_NAT_V6_MINIP],
903 			   sizeof(struct in6_addr));
904 		range->flags |= NF_NAT_RANGE_MAP_IPS;
905 	}
906 
907 	if (tb[CTA_NAT_V6_MAXIP])
908 		nla_memcpy(&range->max_addr.ip6, tb[CTA_NAT_V6_MAXIP],
909 			   sizeof(struct in6_addr));
910 	else
911 		range->max_addr = range->min_addr;
912 
913 	return 0;
914 }
915 
916 static int
nfnetlink_parse_nat(const struct nlattr * nat,const struct nf_conn * ct,struct nf_nat_range2 * range)917 nfnetlink_parse_nat(const struct nlattr *nat,
918 		    const struct nf_conn *ct, struct nf_nat_range2 *range)
919 {
920 	struct nlattr *tb[CTA_NAT_MAX+1];
921 	int err;
922 
923 	memset(range, 0, sizeof(*range));
924 
925 	err = nla_parse_nested_deprecated(tb, CTA_NAT_MAX, nat,
926 					  nat_nla_policy, NULL);
927 	if (err < 0)
928 		return err;
929 
930 	switch (nf_ct_l3num(ct)) {
931 	case NFPROTO_IPV4:
932 		err = nf_nat_ipv4_nlattr_to_range(tb, range);
933 		break;
934 	case NFPROTO_IPV6:
935 		err = nf_nat_ipv6_nlattr_to_range(tb, range);
936 		break;
937 	default:
938 		err = -EPROTONOSUPPORT;
939 		break;
940 	}
941 
942 	if (err)
943 		return err;
944 
945 	if (!tb[CTA_NAT_PROTO])
946 		return 0;
947 
948 	return nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
949 }
950 
951 /* This function is called under rcu_read_lock() */
952 static int
nfnetlink_parse_nat_setup(struct nf_conn * ct,enum nf_nat_manip_type manip,const struct nlattr * attr)953 nfnetlink_parse_nat_setup(struct nf_conn *ct,
954 			  enum nf_nat_manip_type manip,
955 			  const struct nlattr *attr)
956 {
957 	struct nf_nat_range2 range;
958 	int err;
959 
960 	/* Should not happen, restricted to creating new conntracks
961 	 * via ctnetlink.
962 	 */
963 	if (WARN_ON_ONCE(nf_nat_initialized(ct, manip)))
964 		return -EEXIST;
965 
966 	/* No NAT information has been passed, allocate the null-binding */
967 	if (attr == NULL)
968 		return __nf_nat_alloc_null_binding(ct, manip) == NF_DROP ? -ENOMEM : 0;
969 
970 	err = nfnetlink_parse_nat(attr, ct, &range);
971 	if (err < 0)
972 		return err;
973 
974 	return nf_nat_setup_info(ct, &range, manip) == NF_DROP ? -ENOMEM : 0;
975 }
976 #else
977 static int
nfnetlink_parse_nat_setup(struct nf_conn * ct,enum nf_nat_manip_type manip,const struct nlattr * attr)978 nfnetlink_parse_nat_setup(struct nf_conn *ct,
979 			  enum nf_nat_manip_type manip,
980 			  const struct nlattr *attr)
981 {
982 	return -EOPNOTSUPP;
983 }
984 #endif
985 
986 static struct nf_ct_helper_expectfn follow_master_nat = {
987 	.name		= "nat-follow-master",
988 	.expectfn	= nf_nat_follow_master,
989 };
990 
nf_nat_register_fn(struct net * net,u8 pf,const struct nf_hook_ops * ops,const struct nf_hook_ops * orig_nat_ops,unsigned int ops_count)991 int nf_nat_register_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
992 		       const struct nf_hook_ops *orig_nat_ops, unsigned int ops_count)
993 {
994 	struct nat_net *nat_net = net_generic(net, nat_net_id);
995 	struct nf_nat_hooks_net *nat_proto_net;
996 	struct nf_nat_lookup_hook_priv *priv;
997 	unsigned int hooknum = ops->hooknum;
998 	struct nf_hook_ops *nat_ops;
999 	int i, ret;
1000 
1001 	if (WARN_ON_ONCE(pf >= ARRAY_SIZE(nat_net->nat_proto_net)))
1002 		return -EINVAL;
1003 
1004 	nat_proto_net = &nat_net->nat_proto_net[pf];
1005 
1006 	for (i = 0; i < ops_count; i++) {
1007 		if (orig_nat_ops[i].hooknum == hooknum) {
1008 			hooknum = i;
1009 			break;
1010 		}
1011 	}
1012 
1013 	if (WARN_ON_ONCE(i == ops_count))
1014 		return -EINVAL;
1015 
1016 	mutex_lock(&nf_nat_proto_mutex);
1017 	if (!nat_proto_net->nat_hook_ops) {
1018 		WARN_ON(nat_proto_net->users != 0);
1019 
1020 		nat_ops = kmemdup(orig_nat_ops, sizeof(*orig_nat_ops) * ops_count, GFP_KERNEL);
1021 		if (!nat_ops) {
1022 			mutex_unlock(&nf_nat_proto_mutex);
1023 			return -ENOMEM;
1024 		}
1025 
1026 		for (i = 0; i < ops_count; i++) {
1027 			priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1028 			if (priv) {
1029 				nat_ops[i].priv = priv;
1030 				continue;
1031 			}
1032 			mutex_unlock(&nf_nat_proto_mutex);
1033 			while (i)
1034 				kfree(nat_ops[--i].priv);
1035 			kfree(nat_ops);
1036 			return -ENOMEM;
1037 		}
1038 
1039 		ret = nf_register_net_hooks(net, nat_ops, ops_count);
1040 		if (ret < 0) {
1041 			mutex_unlock(&nf_nat_proto_mutex);
1042 			for (i = 0; i < ops_count; i++)
1043 				kfree(nat_ops[i].priv);
1044 			kfree(nat_ops);
1045 			return ret;
1046 		}
1047 
1048 		nat_proto_net->nat_hook_ops = nat_ops;
1049 	}
1050 
1051 	nat_ops = nat_proto_net->nat_hook_ops;
1052 	priv = nat_ops[hooknum].priv;
1053 	if (WARN_ON_ONCE(!priv)) {
1054 		mutex_unlock(&nf_nat_proto_mutex);
1055 		return -EOPNOTSUPP;
1056 	}
1057 
1058 	ret = nf_hook_entries_insert_raw(&priv->entries, ops);
1059 	if (ret == 0)
1060 		nat_proto_net->users++;
1061 
1062 	mutex_unlock(&nf_nat_proto_mutex);
1063 	return ret;
1064 }
1065 
nf_nat_unregister_fn(struct net * net,u8 pf,const struct nf_hook_ops * ops,unsigned int ops_count)1066 void nf_nat_unregister_fn(struct net *net, u8 pf, const struct nf_hook_ops *ops,
1067 			  unsigned int ops_count)
1068 {
1069 	struct nat_net *nat_net = net_generic(net, nat_net_id);
1070 	struct nf_nat_hooks_net *nat_proto_net;
1071 	struct nf_nat_lookup_hook_priv *priv;
1072 	struct nf_hook_ops *nat_ops;
1073 	int hooknum = ops->hooknum;
1074 	int i;
1075 
1076 	if (pf >= ARRAY_SIZE(nat_net->nat_proto_net))
1077 		return;
1078 
1079 	nat_proto_net = &nat_net->nat_proto_net[pf];
1080 
1081 	mutex_lock(&nf_nat_proto_mutex);
1082 	if (WARN_ON(nat_proto_net->users == 0))
1083 		goto unlock;
1084 
1085 	nat_proto_net->users--;
1086 
1087 	nat_ops = nat_proto_net->nat_hook_ops;
1088 	for (i = 0; i < ops_count; i++) {
1089 		if (nat_ops[i].hooknum == hooknum) {
1090 			hooknum = i;
1091 			break;
1092 		}
1093 	}
1094 	if (WARN_ON_ONCE(i == ops_count))
1095 		goto unlock;
1096 	priv = nat_ops[hooknum].priv;
1097 	nf_hook_entries_delete_raw(&priv->entries, ops);
1098 
1099 	if (nat_proto_net->users == 0) {
1100 		nf_unregister_net_hooks(net, nat_ops, ops_count);
1101 
1102 		for (i = 0; i < ops_count; i++) {
1103 			priv = nat_ops[i].priv;
1104 			kfree_rcu(priv, rcu_head);
1105 		}
1106 
1107 		nat_proto_net->nat_hook_ops = NULL;
1108 		kfree(nat_ops);
1109 	}
1110 unlock:
1111 	mutex_unlock(&nf_nat_proto_mutex);
1112 }
1113 
1114 static struct pernet_operations nat_net_ops = {
1115 	.id = &nat_net_id,
1116 	.size = sizeof(struct nat_net),
1117 };
1118 
1119 static const struct nf_nat_hook nat_hook = {
1120 	.parse_nat_setup	= nfnetlink_parse_nat_setup,
1121 #ifdef CONFIG_XFRM
1122 	.decode_session		= __nf_nat_decode_session,
1123 #endif
1124 	.manip_pkt		= nf_nat_manip_pkt,
1125 	.remove_nat_bysrc	= nf_nat_cleanup_conntrack,
1126 };
1127 
nf_nat_init(void)1128 static int __init nf_nat_init(void)
1129 {
1130 	int ret, i;
1131 
1132 	/* Leave them the same for the moment. */
1133 	nf_nat_htable_size = nf_conntrack_htable_size;
1134 	if (nf_nat_htable_size < CONNTRACK_LOCKS)
1135 		nf_nat_htable_size = CONNTRACK_LOCKS;
1136 
1137 	nf_nat_bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size, 0);
1138 	if (!nf_nat_bysource)
1139 		return -ENOMEM;
1140 
1141 	for (i = 0; i < CONNTRACK_LOCKS; i++)
1142 		spin_lock_init(&nf_nat_locks[i]);
1143 
1144 	ret = register_pernet_subsys(&nat_net_ops);
1145 	if (ret < 0) {
1146 		kvfree(nf_nat_bysource);
1147 		return ret;
1148 	}
1149 
1150 	nf_ct_helper_expectfn_register(&follow_master_nat);
1151 
1152 	WARN_ON(nf_nat_hook != NULL);
1153 	RCU_INIT_POINTER(nf_nat_hook, &nat_hook);
1154 
1155 	ret = register_nf_nat_bpf();
1156 	if (ret < 0) {
1157 		RCU_INIT_POINTER(nf_nat_hook, NULL);
1158 		nf_ct_helper_expectfn_unregister(&follow_master_nat);
1159 		synchronize_net();
1160 		unregister_pernet_subsys(&nat_net_ops);
1161 		kvfree(nf_nat_bysource);
1162 	}
1163 
1164 	return ret;
1165 }
1166 
nf_nat_cleanup(void)1167 static void __exit nf_nat_cleanup(void)
1168 {
1169 	struct nf_nat_proto_clean clean = {};
1170 
1171 	nf_ct_iterate_destroy(nf_nat_proto_clean, &clean);
1172 
1173 	nf_ct_helper_expectfn_unregister(&follow_master_nat);
1174 	RCU_INIT_POINTER(nf_nat_hook, NULL);
1175 
1176 	synchronize_net();
1177 	kvfree(nf_nat_bysource);
1178 	unregister_pernet_subsys(&nat_net_ops);
1179 }
1180 
1181 MODULE_LICENSE("GPL");
1182 
1183 module_init(nf_nat_init);
1184 module_exit(nf_nat_cleanup);
1185