1 /*-
2 * Copyright (c) 2014 Yandex LLC.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28
29 /*
30 * Kernel interface tracking API.
31 *
32 */
33
34 #include "opt_ipfw.h"
35 #include "opt_inet.h"
36 #ifndef INET
37 #error IPFIREWALL requires INET.
38 #endif /* INET */
39 #include "opt_inet6.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/malloc.h>
44 #include <sys/kernel.h>
45 #include <sys/lock.h>
46 #include <sys/rwlock.h>
47 #include <sys/rmlock.h>
48 #include <sys/socket.h>
49 #include <sys/queue.h>
50 #include <sys/eventhandler.h>
51 #include <net/if.h>
52 #include <net/if_var.h>
53 #include <net/pfil.h>
54 #include <net/vnet.h>
55
56 #include <netinet/in.h>
57 #include <netinet/ip_var.h> /* struct ipfw_rule_ref */
58 #include <netinet/ip_fw.h>
59
60 #include <netpfil/ipfw/ip_fw_private.h>
61
62 #define CHAIN_TO_II(ch) ((struct namedobj_instance *)ch->ifcfg)
63
64 #define DEFAULT_IFACES 128
65
66 static void handle_ifdetach(struct ip_fw_chain *ch, struct ipfw_iface *iif,
67 uint16_t ifindex);
68 static void handle_ifattach(struct ip_fw_chain *ch, struct ipfw_iface *iif,
69 uint16_t ifindex);
70 static int list_ifaces(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
71 struct sockopt_data *sd);
72
73 static struct ipfw_sopt_handler scodes[] = {
74 { IP_FW_XIFLIST, 0, HDIR_GET, list_ifaces },
75 };
76
77 /*
78 * FreeBSD Kernel interface.
79 */
80 static void ipfw_kifhandler(void *arg, struct ifnet *ifp);
81 static int ipfw_kiflookup(char *name);
82 static void iface_khandler_register(void);
83 static void iface_khandler_deregister(void);
84
85 static eventhandler_tag ipfw_ifdetach_event, ipfw_ifattach_event;
86 static int num_vnets = 0;
87 static struct mtx vnet_mtx;
88
89 /*
90 * Checks if kernel interface is contained in our tracked
91 * interface list and calls attach/detach handler.
92 */
93 static void
ipfw_kifhandler(void * arg,struct ifnet * ifp)94 ipfw_kifhandler(void *arg, struct ifnet *ifp)
95 {
96 struct ip_fw_chain *ch;
97 struct ipfw_iface *iif;
98 struct namedobj_instance *ii;
99 uintptr_t htype;
100
101 if (V_ipfw_vnet_ready == 0)
102 return;
103
104 ch = &V_layer3_chain;
105 htype = (uintptr_t)arg;
106
107 IPFW_UH_WLOCK(ch);
108 ii = CHAIN_TO_II(ch);
109 if (ii == NULL) {
110 IPFW_UH_WUNLOCK(ch);
111 return;
112 }
113 iif = (struct ipfw_iface*)ipfw_objhash_lookup_name(ii, 0,
114 if_name(ifp));
115 if (iif != NULL) {
116 if (htype == 1)
117 handle_ifattach(ch, iif, ifp->if_index);
118 else
119 handle_ifdetach(ch, iif, ifp->if_index);
120 }
121 IPFW_UH_WUNLOCK(ch);
122 }
123
124 /*
125 * Reference current VNET as iface tracking API user.
126 * Registers interface tracking handlers for first VNET.
127 */
128 static void
iface_khandler_register()129 iface_khandler_register()
130 {
131 int create;
132
133 create = 0;
134
135 mtx_lock(&vnet_mtx);
136 if (num_vnets == 0)
137 create = 1;
138 num_vnets++;
139 mtx_unlock(&vnet_mtx);
140
141 if (create == 0)
142 return;
143
144 printf("IPFW: starting up interface tracker\n");
145
146 ipfw_ifdetach_event = EVENTHANDLER_REGISTER(
147 ifnet_departure_event, ipfw_kifhandler, NULL,
148 EVENTHANDLER_PRI_ANY);
149 ipfw_ifattach_event = EVENTHANDLER_REGISTER(
150 ifnet_arrival_event, ipfw_kifhandler, (void*)((uintptr_t)1),
151 EVENTHANDLER_PRI_ANY);
152 }
153
154 /*
155 *
156 * Detach interface event handlers on last VNET instance
157 * detach.
158 */
159 static void
iface_khandler_deregister()160 iface_khandler_deregister()
161 {
162 int destroy;
163
164 destroy = 0;
165 mtx_lock(&vnet_mtx);
166 if (num_vnets == 1)
167 destroy = 1;
168 num_vnets--;
169 mtx_unlock(&vnet_mtx);
170
171 if (destroy == 0)
172 return;
173
174 EVENTHANDLER_DEREGISTER(ifnet_arrival_event,
175 ipfw_ifattach_event);
176 EVENTHANDLER_DEREGISTER(ifnet_departure_event,
177 ipfw_ifdetach_event);
178 }
179
180 /*
181 * Retrieves ifindex for given @name.
182 *
183 * Returns ifindex or 0.
184 */
185 static int
ipfw_kiflookup(char * name)186 ipfw_kiflookup(char *name)
187 {
188 struct ifnet *ifp;
189 int ifindex;
190
191 ifindex = 0;
192
193 if ((ifp = ifunit_ref(name)) != NULL) {
194 ifindex = ifp->if_index;
195 if_rele(ifp);
196 }
197
198 return (ifindex);
199 }
200
201 /*
202 * Global ipfw startup hook.
203 * Since we perform lazy initialization, do nothing except
204 * mutex init.
205 */
206 int
ipfw_iface_init()207 ipfw_iface_init()
208 {
209
210 mtx_init(&vnet_mtx, "IPFW ifhandler mtx", NULL, MTX_DEF);
211 IPFW_ADD_SOPT_HANDLER(1, scodes);
212 return (0);
213 }
214
215 /*
216 * Global ipfw destroy hook.
217 * Unregister khandlers iff init has been done.
218 */
219 void
ipfw_iface_destroy()220 ipfw_iface_destroy()
221 {
222
223 IPFW_DEL_SOPT_HANDLER(1, scodes);
224 mtx_destroy(&vnet_mtx);
225 }
226
227 /*
228 * Perform actual init on internal request.
229 * Inits both namehash and global khandler.
230 */
231 static void
vnet_ipfw_iface_init(struct ip_fw_chain * ch)232 vnet_ipfw_iface_init(struct ip_fw_chain *ch)
233 {
234 struct namedobj_instance *ii;
235
236 ii = ipfw_objhash_create(DEFAULT_IFACES);
237 IPFW_UH_WLOCK(ch);
238 if (ch->ifcfg == NULL) {
239 ch->ifcfg = ii;
240 ii = NULL;
241 }
242 IPFW_UH_WUNLOCK(ch);
243
244 if (ii != NULL) {
245 /* Already initialized. Free namehash. */
246 ipfw_objhash_destroy(ii);
247 } else {
248 /* We're the first ones. Init kernel hooks. */
249 iface_khandler_register();
250 }
251 }
252
253 static int
destroy_iface(struct namedobj_instance * ii,struct named_object * no,void * arg)254 destroy_iface(struct namedobj_instance *ii, struct named_object *no,
255 void *arg)
256 {
257
258 /* Assume all consumers have been already detached */
259 free(no, M_IPFW);
260 return (0);
261 }
262
263 /*
264 * Per-VNET ipfw detach hook.
265 *
266 */
267 void
vnet_ipfw_iface_destroy(struct ip_fw_chain * ch)268 vnet_ipfw_iface_destroy(struct ip_fw_chain *ch)
269 {
270 struct namedobj_instance *ii;
271
272 IPFW_UH_WLOCK(ch);
273 ii = CHAIN_TO_II(ch);
274 ch->ifcfg = NULL;
275 IPFW_UH_WUNLOCK(ch);
276
277 if (ii != NULL) {
278 ipfw_objhash_foreach(ii, destroy_iface, ch);
279 ipfw_objhash_destroy(ii);
280 iface_khandler_deregister();
281 }
282 }
283
284 /*
285 * Notify the subsystem that we are interested in tracking
286 * interface @name. This function has to be called without
287 * holding any locks to permit allocating the necessary states
288 * for proper interface tracking.
289 *
290 * Returns 0 on success.
291 */
292 int
ipfw_iface_ref(struct ip_fw_chain * ch,char * name,struct ipfw_ifc * ic)293 ipfw_iface_ref(struct ip_fw_chain *ch, char *name,
294 struct ipfw_ifc *ic)
295 {
296 struct namedobj_instance *ii;
297 struct ipfw_iface *iif, *tmp;
298
299 if (strlen(name) >= sizeof(iif->ifname))
300 return (EINVAL);
301
302 IPFW_UH_WLOCK(ch);
303
304 ii = CHAIN_TO_II(ch);
305 if (ii == NULL) {
306
307 /*
308 * First request to subsystem.
309 * Let's perform init.
310 */
311 IPFW_UH_WUNLOCK(ch);
312 vnet_ipfw_iface_init(ch);
313 IPFW_UH_WLOCK(ch);
314 ii = CHAIN_TO_II(ch);
315 }
316
317 iif = (struct ipfw_iface *)ipfw_objhash_lookup_name(ii, 0, name);
318
319 if (iif != NULL) {
320 iif->no.refcnt++;
321 ic->iface = iif;
322 IPFW_UH_WUNLOCK(ch);
323 return (0);
324 }
325
326 IPFW_UH_WUNLOCK(ch);
327
328 /* Not found. Let's create one */
329 iif = malloc(sizeof(struct ipfw_iface), M_IPFW, M_WAITOK | M_ZERO);
330 TAILQ_INIT(&iif->consumers);
331 iif->no.name = iif->ifname;
332 strlcpy(iif->ifname, name, sizeof(iif->ifname));
333
334 /*
335 * Ref & link to the list.
336 *
337 * We assume ifnet_arrival_event / ifnet_departure_event
338 * are not holding any locks.
339 */
340 iif->no.refcnt = 1;
341 IPFW_UH_WLOCK(ch);
342
343 tmp = (struct ipfw_iface *)ipfw_objhash_lookup_name(ii, 0, name);
344 if (tmp != NULL) {
345 /* Interface has been created since unlock. Ref and return */
346 tmp->no.refcnt++;
347 ic->iface = tmp;
348 IPFW_UH_WUNLOCK(ch);
349 free(iif, M_IPFW);
350 return (0);
351 }
352
353 iif->ifindex = ipfw_kiflookup(name);
354 if (iif->ifindex != 0)
355 iif->resolved = 1;
356
357 ipfw_objhash_add(ii, &iif->no);
358 ic->iface = iif;
359
360 IPFW_UH_WUNLOCK(ch);
361
362 return (0);
363 }
364
365 /*
366 * Adds @ic to the list of iif interface consumers.
367 * Must be called with holding both UH+WLOCK.
368 * Callback may be immediately called (if interface exists).
369 */
370 void
ipfw_iface_add_notify(struct ip_fw_chain * ch,struct ipfw_ifc * ic)371 ipfw_iface_add_notify(struct ip_fw_chain *ch, struct ipfw_ifc *ic)
372 {
373 struct ipfw_iface *iif;
374
375 IPFW_UH_WLOCK_ASSERT(ch);
376 IPFW_WLOCK_ASSERT(ch);
377
378 iif = ic->iface;
379
380 TAILQ_INSERT_TAIL(&iif->consumers, ic, next);
381 if (iif->resolved != 0)
382 ic->cb(ch, ic->cbdata, iif->ifindex);
383 }
384
385 /*
386 * Unlinks interface tracker object @ic from interface.
387 * Must be called while holding UH lock.
388 */
389 void
ipfw_iface_del_notify(struct ip_fw_chain * ch,struct ipfw_ifc * ic)390 ipfw_iface_del_notify(struct ip_fw_chain *ch, struct ipfw_ifc *ic)
391 {
392 struct ipfw_iface *iif;
393
394 IPFW_UH_WLOCK_ASSERT(ch);
395
396 iif = ic->iface;
397 TAILQ_REMOVE(&iif->consumers, ic, next);
398 }
399
400 /*
401 * Unreference interface specified by @ic.
402 * Must be called while holding UH lock.
403 */
404 void
ipfw_iface_unref(struct ip_fw_chain * ch,struct ipfw_ifc * ic)405 ipfw_iface_unref(struct ip_fw_chain *ch, struct ipfw_ifc *ic)
406 {
407 struct ipfw_iface *iif;
408
409 IPFW_UH_WLOCK_ASSERT(ch);
410
411 iif = ic->iface;
412 ic->iface = NULL;
413
414 iif->no.refcnt--;
415 /* TODO: check for references & delete */
416 }
417
418 /*
419 * Interface arrival handler.
420 */
421 static void
handle_ifattach(struct ip_fw_chain * ch,struct ipfw_iface * iif,uint16_t ifindex)422 handle_ifattach(struct ip_fw_chain *ch, struct ipfw_iface *iif,
423 uint16_t ifindex)
424 {
425 struct ipfw_ifc *ic;
426
427 IPFW_UH_WLOCK_ASSERT(ch);
428
429 iif->gencnt++;
430 iif->resolved = 1;
431 iif->ifindex = ifindex;
432
433 IPFW_WLOCK(ch);
434 TAILQ_FOREACH(ic, &iif->consumers, next)
435 ic->cb(ch, ic->cbdata, iif->ifindex);
436 IPFW_WUNLOCK(ch);
437 }
438
439 /*
440 * Interface departure handler.
441 */
442 static void
handle_ifdetach(struct ip_fw_chain * ch,struct ipfw_iface * iif,uint16_t ifindex)443 handle_ifdetach(struct ip_fw_chain *ch, struct ipfw_iface *iif,
444 uint16_t ifindex)
445 {
446 struct ipfw_ifc *ic;
447
448 IPFW_UH_WLOCK_ASSERT(ch);
449
450 IPFW_WLOCK(ch);
451 TAILQ_FOREACH(ic, &iif->consumers, next)
452 ic->cb(ch, ic->cbdata, 0);
453 IPFW_WUNLOCK(ch);
454
455 iif->gencnt++;
456 iif->resolved = 0;
457 iif->ifindex = 0;
458 }
459
460 struct dump_iface_args {
461 struct ip_fw_chain *ch;
462 struct sockopt_data *sd;
463 };
464
465 static int
export_iface_internal(struct namedobj_instance * ii,struct named_object * no,void * arg)466 export_iface_internal(struct namedobj_instance *ii, struct named_object *no,
467 void *arg)
468 {
469 ipfw_iface_info *i;
470 struct dump_iface_args *da;
471 struct ipfw_iface *iif;
472
473 da = (struct dump_iface_args *)arg;
474
475 i = (ipfw_iface_info *)ipfw_get_sopt_space(da->sd, sizeof(*i));
476 KASSERT(i != NULL, ("previously checked buffer is not enough"));
477
478 iif = (struct ipfw_iface *)no;
479
480 strlcpy(i->ifname, iif->ifname, sizeof(i->ifname));
481 if (iif->resolved)
482 i->flags |= IPFW_IFFLAG_RESOLVED;
483 i->ifindex = iif->ifindex;
484 i->refcnt = iif->no.refcnt;
485 i->gencnt = iif->gencnt;
486 return (0);
487 }
488
489 /*
490 * Lists all interface currently tracked by ipfw.
491 * Data layout (v0)(current):
492 * Request: [ ipfw_obj_lheader ], size = ipfw_obj_lheader.size
493 * Reply: [ ipfw_obj_lheader ipfw_iface_info x N ]
494 *
495 * Returns 0 on success
496 */
497 static int
list_ifaces(struct ip_fw_chain * ch,ip_fw3_opheader * op3,struct sockopt_data * sd)498 list_ifaces(struct ip_fw_chain *ch, ip_fw3_opheader *op3,
499 struct sockopt_data *sd)
500 {
501 struct namedobj_instance *ii;
502 struct _ipfw_obj_lheader *olh;
503 struct dump_iface_args da;
504 uint32_t count, size;
505
506 olh = (struct _ipfw_obj_lheader *)ipfw_get_sopt_header(sd,sizeof(*olh));
507 if (olh == NULL)
508 return (EINVAL);
509 if (sd->valsize < olh->size)
510 return (EINVAL);
511
512 IPFW_UH_RLOCK(ch);
513 ii = CHAIN_TO_II(ch);
514 if (ii != NULL)
515 count = ipfw_objhash_count(ii);
516 else
517 count = 0;
518 size = count * sizeof(ipfw_iface_info) + sizeof(ipfw_obj_lheader);
519
520 /* Fill in header regadless of buffer size */
521 olh->count = count;
522 olh->objsize = sizeof(ipfw_iface_info);
523
524 if (size > olh->size) {
525 olh->size = size;
526 IPFW_UH_RUNLOCK(ch);
527 return (ENOMEM);
528 }
529 olh->size = size;
530
531 da.ch = ch;
532 da.sd = sd;
533
534 if (ii != NULL)
535 ipfw_objhash_foreach(ii, export_iface_internal, &da);
536 IPFW_UH_RUNLOCK(ch);
537
538 return (0);
539 }
540
541