xref: /freebsd/sys/netpfil/ipfw/nptv6/nptv6.c (revision 1db64f89363c97858961c4df0b7d02f3223723cf)
1 /*-
2  * Copyright (c) 2016 Yandex LLC
3  * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/counter.h>
31 #include <sys/eventhandler.h>
32 #include <sys/errno.h>
33 #include <sys/kernel.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/mbuf.h>
37 #include <sys/module.h>
38 #include <sys/rmlock.h>
39 #include <sys/rwlock.h>
40 #include <sys/socket.h>
41 #include <sys/queue.h>
42 #include <sys/syslog.h>
43 #include <sys/sysctl.h>
44 
45 #include <net/if.h>
46 #include <net/if_var.h>
47 #include <net/if_private.h>
48 #include <net/netisr.h>
49 #include <net/pfil.h>
50 #include <net/vnet.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/ip_var.h>
54 #include <netinet/ip_fw.h>
55 #include <netinet/ip6.h>
56 #include <netinet/icmp6.h>
57 #include <netinet6/in6_var.h>
58 #include <netinet6/ip6_var.h>
59 
60 #include <netpfil/ipfw/ip_fw_private.h>
61 #include <netpfil/ipfw/nptv6/nptv6.h>
62 
63 VNET_DEFINE_STATIC(uint16_t, nptv6_eid) = 0;
64 #define	V_nptv6_eid	VNET(nptv6_eid)
65 #define	IPFW_TLV_NPTV6_NAME	IPFW_TLV_EACTION_NAME(V_nptv6_eid)
66 
67 static eventhandler_tag nptv6_ifaddr_event;
68 
69 static struct nptv6_cfg *nptv6_alloc_config(const char *name, uint8_t set);
70 static void nptv6_free_config(struct nptv6_cfg *cfg);
71 static struct nptv6_cfg *nptv6_find(struct namedobj_instance *ni,
72     const char *name, uint8_t set);
73 static int nptv6_rewrite_internal(struct nptv6_cfg *cfg, struct mbuf **mp,
74     int offset);
75 static int nptv6_rewrite_external(struct nptv6_cfg *cfg, struct mbuf **mp,
76     int offset);
77 
78 #define	NPTV6_LOOKUP(chain, cmd)	\
79     (struct nptv6_cfg *)SRV_OBJECT((chain), (cmd)->arg1)
80 
81 #ifndef IN6_MASK_ADDR
82 #define IN6_MASK_ADDR(a, m)	do { \
83 	(a)->s6_addr32[0] &= (m)->s6_addr32[0]; \
84 	(a)->s6_addr32[1] &= (m)->s6_addr32[1]; \
85 	(a)->s6_addr32[2] &= (m)->s6_addr32[2]; \
86 	(a)->s6_addr32[3] &= (m)->s6_addr32[3]; \
87 } while (0)
88 #endif
89 #ifndef IN6_ARE_MASKED_ADDR_EQUAL
90 #define IN6_ARE_MASKED_ADDR_EQUAL(d, a, m)	(	\
91 	(((d)->s6_addr32[0] ^ (a)->s6_addr32[0]) & (m)->s6_addr32[0]) == 0 && \
92 	(((d)->s6_addr32[1] ^ (a)->s6_addr32[1]) & (m)->s6_addr32[1]) == 0 && \
93 	(((d)->s6_addr32[2] ^ (a)->s6_addr32[2]) & (m)->s6_addr32[2]) == 0 && \
94 	(((d)->s6_addr32[3] ^ (a)->s6_addr32[3]) & (m)->s6_addr32[3]) == 0 )
95 #endif
96 
97 #if 0
98 #define	NPTV6_DEBUG(fmt, ...)	do {			\
99 	printf("%s: " fmt "\n", __func__, ## __VA_ARGS__);	\
100 } while (0)
101 #define	NPTV6_IPDEBUG(fmt, ...)	do {			\
102 	char _s[INET6_ADDRSTRLEN], _d[INET6_ADDRSTRLEN];	\
103 	printf("%s: " fmt "\n", __func__, ## __VA_ARGS__);	\
104 } while (0)
105 #else
106 #define	NPTV6_DEBUG(fmt, ...)
107 #define	NPTV6_IPDEBUG(fmt, ...)
108 #endif
109 
110 static int
111 nptv6_getlasthdr(struct nptv6_cfg *cfg, struct mbuf *m, int *offset)
112 {
113 	struct ip6_hdr *ip6;
114 	struct ip6_hbh *hbh;
115 	int proto, hlen;
116 
117 	hlen = (offset == NULL) ? 0: *offset;
118 	if (m->m_len < hlen)
119 		return (-1);
120 	ip6 = mtodo(m, hlen);
121 	hlen += sizeof(*ip6);
122 	proto = ip6->ip6_nxt;
123 	while (proto == IPPROTO_HOPOPTS || proto == IPPROTO_ROUTING ||
124 	    proto == IPPROTO_DSTOPTS) {
125 		hbh = mtodo(m, hlen);
126 		if (m->m_len < hlen)
127 			return (-1);
128 		proto = hbh->ip6h_nxt;
129 		hlen += (hbh->ip6h_len + 1) << 3;
130 	}
131 	if (offset != NULL)
132 		*offset = hlen;
133 	return (proto);
134 }
135 
136 static int
137 nptv6_translate_icmpv6(struct nptv6_cfg *cfg, struct mbuf **mp, int offset)
138 {
139 	struct icmp6_hdr *icmp6;
140 	struct ip6_hdr *ip6;
141 	struct mbuf *m;
142 
143 	m = *mp;
144 	if (offset > m->m_len)
145 		return (-1);
146 	icmp6 = mtodo(m, offset);
147 	NPTV6_DEBUG("ICMPv6 type %d", icmp6->icmp6_type);
148 	switch (icmp6->icmp6_type) {
149 	case ICMP6_DST_UNREACH:
150 	case ICMP6_PACKET_TOO_BIG:
151 	case ICMP6_TIME_EXCEEDED:
152 	case ICMP6_PARAM_PROB:
153 		break;
154 	case ICMP6_ECHO_REQUEST:
155 	case ICMP6_ECHO_REPLY:
156 		/* nothing to translate */
157 		return (0);
158 	default:
159 		/*
160 		 * XXX: We can add some checks to not translate NDP and MLD
161 		 * messages. Currently user must explicitly allow these message
162 		 * types, otherwise packets will be dropped.
163 		 */
164 		return (-1);
165 	}
166 	offset += sizeof(*icmp6);
167 	if (offset + sizeof(*ip6) > m->m_pkthdr.len)
168 		return (-1);
169 	if (offset + sizeof(*ip6) > m->m_len)
170 		*mp = m = m_pullup(m, offset + sizeof(*ip6));
171 	if (m == NULL)
172 		return (-1);
173 	ip6 = mtodo(m, offset);
174 	NPTV6_IPDEBUG("offset %d, %s -> %s %d", offset,
175 	    inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
176 	    inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
177 	    ip6->ip6_nxt);
178 	if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_src,
179 	    &cfg->external, &cfg->mask))
180 		return (nptv6_rewrite_external(cfg, mp, offset));
181 	else if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_dst,
182 	    &cfg->internal, &cfg->mask))
183 		return (nptv6_rewrite_internal(cfg, mp, offset));
184 	/*
185 	 * Addresses in the inner IPv6 header doesn't matched to
186 	 * our prefixes.
187 	 */
188 	return (-1);
189 }
190 
191 static int
192 nptv6_search_index(struct nptv6_cfg *cfg, struct in6_addr *a)
193 {
194 	int idx;
195 
196 	if (cfg->flags & NPTV6_48PLEN)
197 		return (3);
198 
199 	/* Search suitable word index for adjustment */
200 	for (idx = 4; idx < 8; idx++)
201 		if (a->s6_addr16[idx] != 0xffff)
202 			break;
203 	/*
204 	 * RFC 6296 p3.7: If an NPTv6 Translator discovers a datagram with
205 	 * an IID of all-zeros while performing address mapping, that
206 	 * datagram MUST be dropped, and an ICMPv6 Parameter Problem error
207 	 * SHOULD be generated.
208 	 */
209 	if (idx == 8 ||
210 	    (a->s6_addr32[2] == 0 && a->s6_addr32[3] == 0))
211 		return (-1);
212 	return (idx);
213 }
214 
215 static void
216 nptv6_copy_addr(struct in6_addr *src, struct in6_addr *dst,
217     struct in6_addr *mask)
218 {
219 	int i;
220 
221 	for (i = 0; i < 8 && mask->s6_addr8[i] != 0; i++) {
222 		dst->s6_addr8[i] &=  ~mask->s6_addr8[i];
223 		dst->s6_addr8[i] |= src->s6_addr8[i] & mask->s6_addr8[i];
224 	}
225 }
226 
227 static int
228 nptv6_rewrite_internal(struct nptv6_cfg *cfg, struct mbuf **mp, int offset)
229 {
230 	struct in6_addr *addr;
231 	struct ip6_hdr *ip6;
232 	int idx, proto;
233 	uint16_t adj;
234 
235 	ip6 = mtodo(*mp, offset);
236 	NPTV6_IPDEBUG("offset %d, %s -> %s %d", offset,
237 	    inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
238 	    inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
239 	    ip6->ip6_nxt);
240 	if (offset == 0)
241 		addr = &ip6->ip6_src;
242 	else {
243 		/*
244 		 * When we rewriting inner IPv6 header, we need to rewrite
245 		 * destination address back to external prefix. The datagram in
246 		 * the ICMPv6 payload should looks like it was send from
247 		 * external prefix.
248 		 */
249 		addr = &ip6->ip6_dst;
250 	}
251 	idx = nptv6_search_index(cfg, addr);
252 	if (idx < 0) {
253 		/*
254 		 * Do not send ICMPv6 error when offset isn't zero.
255 		 * This means we are rewriting inner IPv6 header in the
256 		 * ICMPv6 error message.
257 		 */
258 		if (offset == 0) {
259 			icmp6_error2(*mp, ICMP6_DST_UNREACH,
260 			    ICMP6_DST_UNREACH_ADDR, 0, (*mp)->m_pkthdr.rcvif);
261 			*mp = NULL;
262 		}
263 		return (IP_FW_DENY);
264 	}
265 	adj = addr->s6_addr16[idx];
266 	nptv6_copy_addr(&cfg->external, addr, &cfg->mask);
267 	adj = cksum_add(adj, cfg->adjustment);
268 	if (adj == 0xffff)
269 		adj = 0;
270 	addr->s6_addr16[idx] = adj;
271 	if (offset == 0) {
272 		/*
273 		 * We may need to translate addresses in the inner IPv6
274 		 * header for ICMPv6 error messages.
275 		 */
276 		proto = nptv6_getlasthdr(cfg, *mp, &offset);
277 		if (proto < 0 || (proto == IPPROTO_ICMPV6 &&
278 		    nptv6_translate_icmpv6(cfg, mp, offset) != 0))
279 			return (IP_FW_DENY);
280 		NPTV6STAT_INC(cfg, in2ex);
281 	}
282 	return (0);
283 }
284 
285 static int
286 nptv6_rewrite_external(struct nptv6_cfg *cfg, struct mbuf **mp, int offset)
287 {
288 	struct in6_addr *addr;
289 	struct ip6_hdr *ip6;
290 	int idx, proto;
291 	uint16_t adj;
292 
293 	ip6 = mtodo(*mp, offset);
294 	NPTV6_IPDEBUG("offset %d, %s -> %s %d", offset,
295 	    inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
296 	    inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
297 	    ip6->ip6_nxt);
298 	if (offset == 0)
299 		addr = &ip6->ip6_dst;
300 	else {
301 		/*
302 		 * When we rewriting inner IPv6 header, we need to rewrite
303 		 * source address back to internal prefix. The datagram in
304 		 * the ICMPv6 payload should looks like it was send from
305 		 * internal prefix.
306 		 */
307 		addr = &ip6->ip6_src;
308 	}
309 	idx = nptv6_search_index(cfg, addr);
310 	if (idx < 0) {
311 		/*
312 		 * Do not send ICMPv6 error when offset isn't zero.
313 		 * This means we are rewriting inner IPv6 header in the
314 		 * ICMPv6 error message.
315 		 */
316 		if (offset == 0) {
317 			icmp6_error2(*mp, ICMP6_DST_UNREACH,
318 			    ICMP6_DST_UNREACH_ADDR, 0, (*mp)->m_pkthdr.rcvif);
319 			*mp = NULL;
320 		}
321 		return (IP_FW_DENY);
322 	}
323 	adj = addr->s6_addr16[idx];
324 	nptv6_copy_addr(&cfg->internal, addr, &cfg->mask);
325 	adj = cksum_add(adj, ~cfg->adjustment);
326 	if (adj == 0xffff)
327 		adj = 0;
328 	addr->s6_addr16[idx] = adj;
329 	if (offset == 0) {
330 		/*
331 		 * We may need to translate addresses in the inner IPv6
332 		 * header for ICMPv6 error messages.
333 		 */
334 		proto = nptv6_getlasthdr(cfg, *mp, &offset);
335 		if (proto < 0 || (proto == IPPROTO_ICMPV6 &&
336 		    nptv6_translate_icmpv6(cfg, mp, offset) != 0))
337 			return (IP_FW_DENY);
338 		NPTV6STAT_INC(cfg, ex2in);
339 	}
340 	return (0);
341 }
342 
343 /*
344  * ipfw external action handler.
345  */
346 static int
347 ipfw_nptv6(struct ip_fw_chain *chain, struct ip_fw_args *args,
348     ipfw_insn *cmd, int *done)
349 {
350 	struct ip6_hdr *ip6;
351 	struct nptv6_cfg *cfg;
352 	ipfw_insn *icmd;
353 	int ret;
354 
355 	*done = 0; /* try next rule if not matched */
356 	ret = IP_FW_DENY;
357 	icmd = cmd + 1;
358 	if (cmd->opcode != O_EXTERNAL_ACTION ||
359 	    cmd->arg1 != V_nptv6_eid ||
360 	    icmd->opcode != O_EXTERNAL_INSTANCE ||
361 	    (cfg = NPTV6_LOOKUP(chain, icmd)) == NULL ||
362 	    (cfg->flags & NPTV6_READY) == 0)
363 		return (ret);
364 	/*
365 	 * We need act as router, so when forwarding is disabled -
366 	 * do nothing.
367 	 */
368 	if (V_ip6_forwarding == 0 || args->f_id.addr_type != 6)
369 		return (ret);
370 	/*
371 	 * NOTE: we expect ipfw_chk() did m_pullup() up to upper level
372 	 * protocol's headers. Also we skip some checks, that ip6_input(),
373 	 * ip6_forward(), ip6_fastfwd() and ipfw_chk() already did.
374 	 */
375 	ip6 = mtod(args->m, struct ip6_hdr *);
376 	NPTV6_IPDEBUG("eid %u, oid %u, %s -> %s %d",
377 	    cmd->arg1, icmd->arg1,
378 	    inet_ntop(AF_INET6, &ip6->ip6_src, _s, sizeof(_s)),
379 	    inet_ntop(AF_INET6, &ip6->ip6_dst, _d, sizeof(_d)),
380 	    ip6->ip6_nxt);
381 	if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_src,
382 	    &cfg->internal, &cfg->mask)) {
383 		/*
384 		 * XXX: Do not translate packets when both src and dst
385 		 * are from internal prefix.
386 		 */
387 		if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_dst,
388 		    &cfg->internal, &cfg->mask))
389 			return (ret);
390 		ret = nptv6_rewrite_internal(cfg, &args->m, 0);
391 	} else if (IN6_ARE_MASKED_ADDR_EQUAL(&ip6->ip6_dst,
392 	    &cfg->external, &cfg->mask))
393 		ret = nptv6_rewrite_external(cfg, &args->m, 0);
394 	else
395 		return (ret);
396 	/*
397 	 * If address wasn't rewrited - free mbuf and terminate the search.
398 	 */
399 	if (ret != 0) {
400 		if (args->m != NULL) {
401 			m_freem(args->m);
402 			args->m = NULL; /* mark mbuf as consumed */
403 		}
404 		NPTV6STAT_INC(cfg, dropped);
405 		*done = 1;
406 	} else {
407 		/* Terminate the search if one_pass is set */
408 		*done = V_fw_one_pass;
409 		/* Update args->f_id when one_pass is off */
410 		if (*done == 0) {
411 			ip6 = mtod(args->m, struct ip6_hdr *);
412 			args->f_id.src_ip6 = ip6->ip6_src;
413 			args->f_id.dst_ip6 = ip6->ip6_dst;
414 		}
415 	}
416 	return (ret);
417 }
418 
419 static struct nptv6_cfg *
420 nptv6_alloc_config(const char *name, uint8_t set)
421 {
422 	struct nptv6_cfg *cfg;
423 
424 	cfg = malloc(sizeof(struct nptv6_cfg), M_IPFW, M_WAITOK | M_ZERO);
425 	COUNTER_ARRAY_ALLOC(cfg->stats, NPTV6STATS, M_WAITOK);
426 	cfg->no.name = cfg->name;
427 	cfg->no.etlv = IPFW_TLV_NPTV6_NAME;
428 	cfg->no.set = set;
429 	strlcpy(cfg->name, name, sizeof(cfg->name));
430 	return (cfg);
431 }
432 
433 static void
434 nptv6_free_config(struct nptv6_cfg *cfg)
435 {
436 
437 	COUNTER_ARRAY_FREE(cfg->stats, NPTV6STATS);
438 	free(cfg, M_IPFW);
439 }
440 
441 static void
442 nptv6_export_config(struct ip_fw_chain *ch, struct nptv6_cfg *cfg,
443     ipfw_nptv6_cfg *uc)
444 {
445 
446 	uc->internal = cfg->internal;
447 	if (cfg->flags & NPTV6_DYNAMIC_PREFIX)
448 		memcpy(uc->if_name, cfg->if_name, IF_NAMESIZE);
449 	else
450 		uc->external = cfg->external;
451 	uc->plen = cfg->plen;
452 	uc->flags = cfg->flags & NPTV6_FLAGSMASK;
453 	uc->set = cfg->no.set;
454 	strlcpy(uc->name, cfg->no.name, sizeof(uc->name));
455 }
456 
457 struct nptv6_dump_arg {
458 	struct ip_fw_chain *ch;
459 	struct sockopt_data *sd;
460 };
461 
462 static int
463 export_config_cb(struct namedobj_instance *ni, struct named_object *no,
464     void *arg)
465 {
466 	struct nptv6_dump_arg *da = (struct nptv6_dump_arg *)arg;
467 	ipfw_nptv6_cfg *uc;
468 
469 	uc = (ipfw_nptv6_cfg *)ipfw_get_sopt_space(da->sd, sizeof(*uc));
470 	nptv6_export_config(da->ch, (struct nptv6_cfg *)no, uc);
471 	return (0);
472 }
473 
474 static struct nptv6_cfg *
475 nptv6_find(struct namedobj_instance *ni, const char *name, uint8_t set)
476 {
477 	struct nptv6_cfg *cfg;
478 
479 	cfg = (struct nptv6_cfg *)ipfw_objhash_lookup_name_type(ni, set,
480 	    IPFW_TLV_NPTV6_NAME, name);
481 
482 	return (cfg);
483 }
484 
485 static void
486 nptv6_calculate_adjustment(struct nptv6_cfg *cfg)
487 {
488 	uint16_t i, e;
489 	uint16_t *p;
490 
491 	/* Calculate checksum of internal prefix */
492 	for (i = 0, p = (uint16_t *)&cfg->internal;
493 	    p < (uint16_t *)(&cfg->internal + 1); p++)
494 		i = cksum_add(i, *p);
495 
496 	/* Calculate checksum of external prefix */
497 	for (e = 0, p = (uint16_t *)&cfg->external;
498 	    p < (uint16_t *)(&cfg->external + 1); p++)
499 		e = cksum_add(e, *p);
500 
501 	/* Adjustment value for Int->Ext direction */
502 	cfg->adjustment = cksum_add(~e, i);
503 }
504 
505 static int
506 nptv6_check_prefix(const struct in6_addr *addr)
507 {
508 
509 	if (IN6_IS_ADDR_MULTICAST(addr) ||
510 	    IN6_IS_ADDR_LINKLOCAL(addr) ||
511 	    IN6_IS_ADDR_LOOPBACK(addr) ||
512 	    IN6_IS_ADDR_UNSPECIFIED(addr))
513 		return (EINVAL);
514 	return (0);
515 }
516 
517 static void
518 nptv6_set_external(struct nptv6_cfg *cfg, struct in6_addr *addr)
519 {
520 
521 	cfg->external = *addr;
522 	IN6_MASK_ADDR(&cfg->external, &cfg->mask);
523 	nptv6_calculate_adjustment(cfg);
524 	cfg->flags |= NPTV6_READY;
525 }
526 
527 /*
528  * Try to determine what prefix to use as external for
529  * configured interface name.
530  */
531 static void
532 nptv6_find_prefix(struct ip_fw_chain *ch, struct nptv6_cfg *cfg,
533     struct ifnet *ifp)
534 {
535 	struct epoch_tracker et;
536 	struct ifaddr *ifa;
537 	struct in6_ifaddr *ia;
538 
539 	MPASS(cfg->flags & NPTV6_DYNAMIC_PREFIX);
540 	IPFW_UH_WLOCK_ASSERT(ch);
541 
542 	if (ifp == NULL) {
543 		ifp = ifunit_ref(cfg->if_name);
544 		if (ifp == NULL)
545 			return;
546 	}
547 	NET_EPOCH_ENTER(et);
548 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
549 		if (ifa->ifa_addr->sa_family != AF_INET6)
550 			continue;
551 		ia = (struct in6_ifaddr *)ifa;
552 		if (nptv6_check_prefix(&ia->ia_addr.sin6_addr) ||
553 		    IN6_ARE_MASKED_ADDR_EQUAL(&ia->ia_addr.sin6_addr,
554 		    &cfg->internal, &cfg->mask))
555 			continue;
556 		/* Suitable address is found. */
557 		nptv6_set_external(cfg, &ia->ia_addr.sin6_addr);
558 		break;
559 	}
560 	NET_EPOCH_EXIT(et);
561 	if_rele(ifp);
562 }
563 
564 struct ifaddr_event_args {
565 	struct ifnet *ifp;
566 	const struct in6_addr *addr;
567 	int event;
568 };
569 
570 static int
571 ifaddr_cb(struct namedobj_instance *ni, struct named_object *no,
572     void *arg)
573 {
574 	struct ifaddr_event_args *args;
575 	struct ip_fw_chain *ch;
576 	struct nptv6_cfg *cfg;
577 
578 	ch = &V_layer3_chain;
579 	cfg = (struct nptv6_cfg *)SRV_OBJECT(ch, no->kidx);
580 	if ((cfg->flags & NPTV6_DYNAMIC_PREFIX) == 0)
581 		return (0);
582 
583 	args = arg;
584 	/* If interface name doesn't match, ignore */
585 	if (strncmp(args->ifp->if_xname, cfg->if_name, IF_NAMESIZE))
586 		return (0);
587 	if (args->ifp->if_flags & IFF_DYING) { /* XXX: is it possible? */
588 		cfg->flags &= ~NPTV6_READY;
589 		return (0);
590 	}
591 	if (args->event == IFADDR_EVENT_DEL) {
592 		/* If instance is not ready, ignore */
593 		if ((cfg->flags & NPTV6_READY) == 0)
594 			return (0);
595 		/* If address does not match the external prefix, ignore */
596 		if (IN6_ARE_MASKED_ADDR_EQUAL(&cfg->external, args->addr,
597 		    &cfg->mask) != 0)
598 			return (0);
599 		/* Otherwise clear READY flag */
600 		cfg->flags &= ~NPTV6_READY;
601 	} else {/* IFADDR_EVENT_ADD */
602 		/* If instance is already ready, ignore */
603 		if (cfg->flags & NPTV6_READY)
604 			return (0);
605 		/* If address is not suitable for prefix, ignore */
606 		if (nptv6_check_prefix(args->addr) ||
607 		    IN6_ARE_MASKED_ADDR_EQUAL(args->addr, &cfg->internal,
608 		    &cfg->mask))
609 			return (0);
610 		/* FALLTHROUGH */
611 	}
612 	MPASS(!(cfg->flags & NPTV6_READY));
613 	/* Try to determine the prefix */
614 	if_ref(args->ifp);
615 	nptv6_find_prefix(ch, cfg, args->ifp);
616 	return (0);
617 }
618 
619 static void
620 nptv6_ifaddrevent_handler(void *arg __unused, struct ifnet *ifp,
621     struct ifaddr *ifa, int event)
622 {
623 	struct ifaddr_event_args args;
624 	struct ip_fw_chain *ch;
625 
626 	if (ifa->ifa_addr->sa_family != AF_INET6)
627 		return;
628 
629 	args.ifp = ifp;
630 	args.addr = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
631 	args.event = event;
632 
633 	ch = &V_layer3_chain;
634 	IPFW_UH_WLOCK(ch);
635 	ipfw_objhash_foreach_type(CHAIN_TO_SRV(ch), ifaddr_cb, &args,
636 	    IPFW_TLV_NPTV6_NAME);
637 	IPFW_UH_WUNLOCK(ch);
638 }
639 
640 /*
641  * Creates new NPTv6 instance.
642  * Data layout (v0)(current):
643  * Request: [ ipfw_obj_lheader ipfw_nptv6_cfg ]
644  *
645  * Returns 0 on success
646  */
647 static int
648 nptv6_create(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
649     struct sockopt_data *sd)
650 {
651 	struct in6_addr mask;
652 	ipfw_obj_lheader *olh;
653 	ipfw_nptv6_cfg *uc;
654 	struct namedobj_instance *ni;
655 	struct nptv6_cfg *cfg;
656 
657 	if (sd->valsize != sizeof(*olh) + sizeof(*uc))
658 		return (EINVAL);
659 
660 	olh = (ipfw_obj_lheader *)sd->kbuf;
661 	uc = (ipfw_nptv6_cfg *)(olh + 1);
662 	if (ipfw_check_object_name_generic(uc->name) != 0)
663 		return (EINVAL);
664 	if (uc->plen < 8 || uc->plen > 64 || uc->set >= IPFW_MAX_SETS)
665 		return (EINVAL);
666 	if (nptv6_check_prefix(&uc->internal))
667 		return (EINVAL);
668 	in6_prefixlen2mask(&mask, uc->plen);
669 	if ((uc->flags & NPTV6_DYNAMIC_PREFIX) == 0 && (
670 	    nptv6_check_prefix(&uc->external) ||
671 	    IN6_ARE_MASKED_ADDR_EQUAL(&uc->external, &uc->internal, &mask)))
672 		return (EINVAL);
673 
674 	ni = CHAIN_TO_SRV(ch);
675 	IPFW_UH_RLOCK(ch);
676 	if (nptv6_find(ni, uc->name, uc->set) != NULL) {
677 		IPFW_UH_RUNLOCK(ch);
678 		return (EEXIST);
679 	}
680 	IPFW_UH_RUNLOCK(ch);
681 
682 	cfg = nptv6_alloc_config(uc->name, uc->set);
683 	cfg->plen = uc->plen;
684 	cfg->flags = uc->flags & NPTV6_FLAGSMASK;
685 	if (cfg->plen <= 48)
686 		cfg->flags |= NPTV6_48PLEN;
687 	cfg->mask = mask;
688 	cfg->internal = uc->internal;
689 	IN6_MASK_ADDR(&cfg->internal, &mask);
690 	if (cfg->flags & NPTV6_DYNAMIC_PREFIX)
691 		memcpy(cfg->if_name, uc->if_name, IF_NAMESIZE);
692 	else
693 		nptv6_set_external(cfg, &uc->external);
694 
695 	if ((uc->flags & NPTV6_DYNAMIC_PREFIX) != 0 &&
696 	    nptv6_ifaddr_event == NULL)
697 		nptv6_ifaddr_event = EVENTHANDLER_REGISTER(
698 		    ifaddr_event_ext, nptv6_ifaddrevent_handler, NULL,
699 		    EVENTHANDLER_PRI_ANY);
700 
701 	IPFW_UH_WLOCK(ch);
702 	if (ipfw_objhash_alloc_idx(ni, &cfg->no.kidx) != 0) {
703 		IPFW_UH_WUNLOCK(ch);
704 		nptv6_free_config(cfg);
705 		return (ENOSPC);
706 	}
707 	ipfw_objhash_add(ni, &cfg->no);
708 	SRV_OBJECT(ch, cfg->no.kidx) = cfg;
709 	if (cfg->flags & NPTV6_DYNAMIC_PREFIX)
710 		nptv6_find_prefix(ch, cfg, NULL);
711 	IPFW_UH_WUNLOCK(ch);
712 
713 	return (0);
714 }
715 
716 /*
717  * Destroys NPTv6 instance.
718  * Data layout (v0)(current):
719  * Request: [ ipfw_obj_header ]
720  *
721  * Returns 0 on success
722  */
723 static int
724 nptv6_destroy(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
725     struct sockopt_data *sd)
726 {
727 	ipfw_obj_header *oh;
728 	struct nptv6_cfg *cfg;
729 
730 	if (sd->valsize != sizeof(*oh))
731 		return (EINVAL);
732 
733 	oh = (ipfw_obj_header *)sd->kbuf;
734 	if (ipfw_check_object_name_generic(oh->ntlv.name) != 0)
735 		return (EINVAL);
736 
737 	IPFW_UH_WLOCK(ch);
738 	cfg = nptv6_find(CHAIN_TO_SRV(ch), oh->ntlv.name, oh->ntlv.set);
739 	if (cfg == NULL) {
740 		IPFW_UH_WUNLOCK(ch);
741 		return (ESRCH);
742 	}
743 	if (cfg->no.refcnt > 0) {
744 		IPFW_UH_WUNLOCK(ch);
745 		return (EBUSY);
746 	}
747 
748 	ipfw_reset_eaction_instance(ch, V_nptv6_eid, cfg->no.kidx);
749 	SRV_OBJECT(ch, cfg->no.kidx) = NULL;
750 	ipfw_objhash_del(CHAIN_TO_SRV(ch), &cfg->no);
751 	ipfw_objhash_free_idx(CHAIN_TO_SRV(ch), cfg->no.kidx);
752 	IPFW_UH_WUNLOCK(ch);
753 
754 	nptv6_free_config(cfg);
755 	return (0);
756 }
757 
758 /*
759  * Get or change nptv6 instance config.
760  * Request: [ ipfw_obj_header [ ipfw_nptv6_cfg ] ]
761  */
762 static int
763 nptv6_config(struct ip_fw_chain *chain, ip_fw3_opheader *op,
764     struct sockopt_data *sd)
765 {
766 
767 	return (EOPNOTSUPP);
768 }
769 
770 /*
771  * Lists all NPTv6 instances currently available in kernel.
772  * Data layout (v0)(current):
773  * Request: [ ipfw_obj_lheader ]
774  * Reply: [ ipfw_obj_lheader ipfw_nptv6_cfg x N ]
775  *
776  * Returns 0 on success
777  */
778 static int
779 nptv6_list(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
780     struct sockopt_data *sd)
781 {
782 	ipfw_obj_lheader *olh;
783 	struct nptv6_dump_arg da;
784 
785 	/* Check minimum header size */
786 	if (sd->valsize < sizeof(ipfw_obj_lheader))
787 		return (EINVAL);
788 
789 	olh = (ipfw_obj_lheader *)ipfw_get_sopt_header(sd, sizeof(*olh));
790 
791 	IPFW_UH_RLOCK(ch);
792 	olh->count = ipfw_objhash_count_type(CHAIN_TO_SRV(ch),
793 	    IPFW_TLV_NPTV6_NAME);
794 	olh->objsize = sizeof(ipfw_nptv6_cfg);
795 	olh->size = sizeof(*olh) + olh->count * olh->objsize;
796 
797 	if (sd->valsize < olh->size) {
798 		IPFW_UH_RUNLOCK(ch);
799 		return (ENOMEM);
800 	}
801 	memset(&da, 0, sizeof(da));
802 	da.ch = ch;
803 	da.sd = sd;
804 	ipfw_objhash_foreach_type(CHAIN_TO_SRV(ch), export_config_cb,
805 	    &da, IPFW_TLV_NPTV6_NAME);
806 	IPFW_UH_RUNLOCK(ch);
807 
808 	return (0);
809 }
810 
811 #define	__COPY_STAT_FIELD(_cfg, _stats, _field)	\
812 	(_stats)->_field = NPTV6STAT_FETCH(_cfg, _field)
813 static void
814 export_stats(struct ip_fw_chain *ch, struct nptv6_cfg *cfg,
815     struct ipfw_nptv6_stats *stats)
816 {
817 
818 	__COPY_STAT_FIELD(cfg, stats, in2ex);
819 	__COPY_STAT_FIELD(cfg, stats, ex2in);
820 	__COPY_STAT_FIELD(cfg, stats, dropped);
821 }
822 
823 /*
824  * Get NPTv6 statistics.
825  * Data layout (v0)(current):
826  * Request: [ ipfw_obj_header ]
827  * Reply: [ ipfw_obj_header ipfw_obj_ctlv [ uint64_t x N ]]
828  *
829  * Returns 0 on success
830  */
831 static int
832 nptv6_stats(struct ip_fw_chain *ch, ip_fw3_opheader *op,
833     struct sockopt_data *sd)
834 {
835 	struct ipfw_nptv6_stats stats;
836 	struct nptv6_cfg *cfg;
837 	ipfw_obj_header *oh;
838 	ipfw_obj_ctlv *ctlv;
839 	size_t sz;
840 
841 	sz = sizeof(ipfw_obj_header) + sizeof(ipfw_obj_ctlv) + sizeof(stats);
842 	if (sd->valsize % sizeof(uint64_t))
843 		return (EINVAL);
844 	if (sd->valsize < sz)
845 		return (ENOMEM);
846 	oh = (ipfw_obj_header *)ipfw_get_sopt_header(sd, sz);
847 	if (oh == NULL)
848 		return (EINVAL);
849 	if (ipfw_check_object_name_generic(oh->ntlv.name) != 0 ||
850 	    oh->ntlv.set >= IPFW_MAX_SETS)
851 		return (EINVAL);
852 	memset(&stats, 0, sizeof(stats));
853 
854 	IPFW_UH_RLOCK(ch);
855 	cfg = nptv6_find(CHAIN_TO_SRV(ch), oh->ntlv.name, oh->ntlv.set);
856 	if (cfg == NULL) {
857 		IPFW_UH_RUNLOCK(ch);
858 		return (ESRCH);
859 	}
860 	export_stats(ch, cfg, &stats);
861 	IPFW_UH_RUNLOCK(ch);
862 
863 	ctlv = (ipfw_obj_ctlv *)(oh + 1);
864 	memset(ctlv, 0, sizeof(*ctlv));
865 	ctlv->head.type = IPFW_TLV_COUNTERS;
866 	ctlv->head.length = sz - sizeof(ipfw_obj_header);
867 	ctlv->count = sizeof(stats) / sizeof(uint64_t);
868 	ctlv->objsize = sizeof(uint64_t);
869 	ctlv->version = 1;
870 	memcpy(ctlv + 1, &stats, sizeof(stats));
871 	return (0);
872 }
873 
874 /*
875  * Reset NPTv6 statistics.
876  * Data layout (v0)(current):
877  * Request: [ ipfw_obj_header ]
878  *
879  * Returns 0 on success
880  */
881 static int
882 nptv6_reset_stats(struct ip_fw_chain *ch, ip_fw3_opheader *op,
883     struct sockopt_data *sd)
884 {
885 	struct nptv6_cfg *cfg;
886 	ipfw_obj_header *oh;
887 
888 	if (sd->valsize != sizeof(*oh))
889 		return (EINVAL);
890 	oh = (ipfw_obj_header *)sd->kbuf;
891 	if (ipfw_check_object_name_generic(oh->ntlv.name) != 0 ||
892 	    oh->ntlv.set >= IPFW_MAX_SETS)
893 		return (EINVAL);
894 
895 	IPFW_UH_WLOCK(ch);
896 	cfg = nptv6_find(CHAIN_TO_SRV(ch), oh->ntlv.name, oh->ntlv.set);
897 	if (cfg == NULL) {
898 		IPFW_UH_WUNLOCK(ch);
899 		return (ESRCH);
900 	}
901 	COUNTER_ARRAY_ZERO(cfg->stats, NPTV6STATS);
902 	IPFW_UH_WUNLOCK(ch);
903 	return (0);
904 }
905 
906 static struct ipfw_sopt_handler	scodes[] = {
907 	{ IP_FW_NPTV6_CREATE, 0,	HDIR_SET,	nptv6_create },
908 	{ IP_FW_NPTV6_DESTROY,0,	HDIR_SET,	nptv6_destroy },
909 	{ IP_FW_NPTV6_CONFIG, 0,	HDIR_BOTH,	nptv6_config },
910 	{ IP_FW_NPTV6_LIST,   0,	HDIR_GET,	nptv6_list },
911 	{ IP_FW_NPTV6_STATS,  0,	HDIR_GET,	nptv6_stats },
912 	{ IP_FW_NPTV6_RESET_STATS,0,	HDIR_SET,	nptv6_reset_stats },
913 };
914 
915 static int
916 nptv6_classify(ipfw_insn *cmd, uint16_t *puidx, uint8_t *ptype)
917 {
918 	ipfw_insn *icmd;
919 
920 	icmd = cmd - 1;
921 	NPTV6_DEBUG("opcode %d, arg1 %d, opcode0 %d, arg1 %d",
922 	    cmd->opcode, cmd->arg1, icmd->opcode, icmd->arg1);
923 	if (icmd->opcode != O_EXTERNAL_ACTION ||
924 	    icmd->arg1 != V_nptv6_eid)
925 		return (1);
926 
927 	*puidx = cmd->arg1;
928 	*ptype = 0;
929 	return (0);
930 }
931 
932 static void
933 nptv6_update_arg1(ipfw_insn *cmd, uint16_t idx)
934 {
935 
936 	cmd->arg1 = idx;
937 	NPTV6_DEBUG("opcode %d, arg1 -> %d", cmd->opcode, cmd->arg1);
938 }
939 
940 static int
941 nptv6_findbyname(struct ip_fw_chain *ch, struct tid_info *ti,
942     struct named_object **pno)
943 {
944 	int err;
945 
946 	err = ipfw_objhash_find_type(CHAIN_TO_SRV(ch), ti,
947 	    IPFW_TLV_NPTV6_NAME, pno);
948 	NPTV6_DEBUG("uidx %u, type %u, err %d", ti->uidx, ti->type, err);
949 	return (err);
950 }
951 
952 static struct named_object *
953 nptv6_findbykidx(struct ip_fw_chain *ch, uint16_t idx)
954 {
955 	struct namedobj_instance *ni;
956 	struct named_object *no;
957 
958 	IPFW_UH_WLOCK_ASSERT(ch);
959 	ni = CHAIN_TO_SRV(ch);
960 	no = ipfw_objhash_lookup_kidx(ni, idx);
961 	KASSERT(no != NULL, ("NPT with index %d not found", idx));
962 
963 	NPTV6_DEBUG("kidx %u -> %s", idx, no->name);
964 	return (no);
965 }
966 
967 static int
968 nptv6_manage_sets(struct ip_fw_chain *ch, uint16_t set, uint8_t new_set,
969     enum ipfw_sets_cmd cmd)
970 {
971 
972 	return (ipfw_obj_manage_sets(CHAIN_TO_SRV(ch), IPFW_TLV_NPTV6_NAME,
973 	    set, new_set, cmd));
974 }
975 
976 static struct opcode_obj_rewrite opcodes[] = {
977 	{
978 		.opcode	= O_EXTERNAL_INSTANCE,
979 		.etlv = IPFW_TLV_EACTION /* just show it isn't table */,
980 		.classifier = nptv6_classify,
981 		.update = nptv6_update_arg1,
982 		.find_byname = nptv6_findbyname,
983 		.find_bykidx = nptv6_findbykidx,
984 		.manage_sets = nptv6_manage_sets,
985 	},
986 };
987 
988 static int
989 destroy_config_cb(struct namedobj_instance *ni, struct named_object *no,
990     void *arg)
991 {
992 	struct nptv6_cfg *cfg;
993 	struct ip_fw_chain *ch;
994 
995 	ch = (struct ip_fw_chain *)arg;
996 	IPFW_UH_WLOCK_ASSERT(ch);
997 
998 	cfg = (struct nptv6_cfg *)SRV_OBJECT(ch, no->kidx);
999 	SRV_OBJECT(ch, no->kidx) = NULL;
1000 	ipfw_objhash_del(ni, &cfg->no);
1001 	ipfw_objhash_free_idx(ni, cfg->no.kidx);
1002 	nptv6_free_config(cfg);
1003 	return (0);
1004 }
1005 
1006 int
1007 nptv6_init(struct ip_fw_chain *ch, int first)
1008 {
1009 
1010 	V_nptv6_eid = ipfw_add_eaction(ch, ipfw_nptv6, "nptv6");
1011 	if (V_nptv6_eid == 0)
1012 		return (ENXIO);
1013 	IPFW_ADD_SOPT_HANDLER(first, scodes);
1014 	IPFW_ADD_OBJ_REWRITER(first, opcodes);
1015 	return (0);
1016 }
1017 
1018 void
1019 nptv6_uninit(struct ip_fw_chain *ch, int last)
1020 {
1021 
1022 	if (last && nptv6_ifaddr_event != NULL)
1023 		EVENTHANDLER_DEREGISTER(ifaddr_event_ext, nptv6_ifaddr_event);
1024 	IPFW_DEL_OBJ_REWRITER(last, opcodes);
1025 	IPFW_DEL_SOPT_HANDLER(last, scodes);
1026 	ipfw_del_eaction(ch, V_nptv6_eid);
1027 	/*
1028 	 * Since we already have deregistered external action,
1029 	 * our named objects become unaccessible via rules, because
1030 	 * all rules were truncated by ipfw_del_eaction().
1031 	 * So, we can unlink and destroy our named objects without holding
1032 	 * IPFW_WLOCK().
1033 	 */
1034 	IPFW_UH_WLOCK(ch);
1035 	ipfw_objhash_foreach_type(CHAIN_TO_SRV(ch), destroy_config_cb, ch,
1036 	    IPFW_TLV_NPTV6_NAME);
1037 	V_nptv6_eid = 0;
1038 	IPFW_UH_WUNLOCK(ch);
1039 }
1040