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npf_os.c revision 1.5 
      1 /*	$NetBSD: npf_os.c,v 1.5 2017/01/03 00:58:05 rmind Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2009-2016 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This material is based upon work partially supported by The
      8  * NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * NPF main: dynamic load/initialisation and unload routines.
     34  */
     35 
     36 #ifdef _KERNEL
     37 #include <sys/cdefs.h>
     38 __KERNEL_RCSID(0, "$NetBSD: npf_os.c,v 1.5 2017/01/03 00:58:05 rmind Exp $");
     39 
     40 #ifdef _KERNEL_OPT
     41 #include "pf.h"
     42 #if NPF > 0
     43 #error "NPF and PF are mutually exclusive; please select one"
     44 #endif
     45 #endif
     46 
     47 #include <sys/param.h>
     48 #include <sys/types.h>
     49 
     50 #include <sys/conf.h>
     51 #include <sys/kauth.h>
     52 #include <sys/kmem.h>
     53 #include <sys/lwp.h>
     54 #include <sys/module.h>
     55 #include <sys/socketvar.h>
     56 #include <sys/uio.h>
     57 
     58 #include <netinet/in.h>
     59 #include <netinet6/in6_var.h>
     60 #endif
     61 
     62 #include "npf_impl.h"
     63 #include "npfkern.h"
     64 
     65 #ifdef _KERNEL
     66 #ifndef _MODULE
     67 #include "opt_modular.h"
     68 #endif
     69 #include "ioconf.h"
     70 #endif
     71 
     72 /*
     73  * Module and device structures.
     74  */
     75 #ifndef _MODULE
     76 /*
     77  * Modular kernels load drivers too early, and we need percpu to be inited
     78  * So we make this misc; a better way would be to have early boot and late
     79  * boot drivers.
     80  */
     81 MODULE(MODULE_CLASS_MISC, npf, NULL);
     82 #else
     83 /* This module autoloads via /dev/npf so it needs to be a driver */
     84 MODULE(MODULE_CLASS_DRIVER, npf, NULL);
     85 #endif
     86 
     87 static int	npf_dev_open(dev_t, int, int, lwp_t *);
     88 static int	npf_dev_close(dev_t, int, int, lwp_t *);
     89 static int	npf_dev_ioctl(dev_t, u_long, void *, int, lwp_t *);
     90 static int	npf_dev_poll(dev_t, int, lwp_t *);
     91 static int	npf_dev_read(dev_t, struct uio *, int);
     92 
     93 const struct cdevsw npf_cdevsw = {
     94 	.d_open = npf_dev_open,
     95 	.d_close = npf_dev_close,
     96 	.d_read = npf_dev_read,
     97 	.d_write = nowrite,
     98 	.d_ioctl = npf_dev_ioctl,
     99 	.d_stop = nostop,
    100 	.d_tty = notty,
    101 	.d_poll = npf_dev_poll,
    102 	.d_mmap = nommap,
    103 	.d_kqfilter = nokqfilter,
    104 	.d_discard = nodiscard,
    105 	.d_flag = D_OTHER | D_MPSAFE
    106 };
    107 
    108 static const char *	npf_ifop_getname(ifnet_t *);
    109 static ifnet_t *	npf_ifop_lookup(const char *);
    110 static void		npf_ifop_flush(void *);
    111 static void *		npf_ifop_getmeta(const ifnet_t *);
    112 static void		npf_ifop_setmeta(ifnet_t *, void *);
    113 
    114 static const unsigned	nworkers = 1;
    115 
    116 static bool		pfil_registered = false;
    117 static pfil_head_t *	npf_ph_if = NULL;
    118 static pfil_head_t *	npf_ph_inet = NULL;
    119 static pfil_head_t *	npf_ph_inet6 = NULL;
    120 
    121 static const npf_ifops_t kern_ifops = {
    122 	.getname	= npf_ifop_getname,
    123 	.lookup		= npf_ifop_lookup,
    124 	.flush		= npf_ifop_flush,
    125 	.getmeta	= npf_ifop_getmeta,
    126 	.setmeta	= npf_ifop_setmeta,
    127 };
    128 
    129 static int
    130 npf_fini(void)
    131 {
    132 	npf_t *npf = npf_getkernctx();
    133 
    134 	/* At first, detach device and remove pfil hooks. */
    135 #ifdef _MODULE
    136 	devsw_detach(NULL, &npf_cdevsw);
    137 #endif
    138 	npf_pfil_unregister(true);
    139 	npf_destroy(npf);
    140 	npf_sysfini();
    141 	return 0;
    142 }
    143 
    144 static int
    145 npf_init(void)
    146 {
    147 	npf_t *npf;
    148 	int error = 0;
    149 
    150 	error = npf_sysinit(nworkers);
    151 	if (error)
    152 		return error;
    153 	npf = npf_create(0, NULL, &kern_ifops);
    154 	npf_setkernctx(npf);
    155 	npf_pfil_register(true);
    156 
    157 #ifdef _MODULE
    158 	devmajor_t bmajor = NODEVMAJOR, cmajor = NODEVMAJOR;
    159 
    160 	/* Attach /dev/npf device. */
    161 	error = devsw_attach("npf", NULL, &bmajor, &npf_cdevsw, &cmajor);
    162 	if (error) {
    163 		/* It will call devsw_detach(), which is safe. */
    164 		(void)npf_fini();
    165 	}
    166 #endif
    167 	return error;
    168 }
    169 
    170 
    171 /*
    172  * Module interface.
    173  */
    174 static int
    175 npf_modcmd(modcmd_t cmd, void *arg)
    176 {
    177 	switch (cmd) {
    178 	case MODULE_CMD_INIT:
    179 		return npf_init();
    180 	case MODULE_CMD_FINI:
    181 		return npf_fini();
    182 	case MODULE_CMD_AUTOUNLOAD:
    183 		if (npf_autounload_p()) {
    184 			return EBUSY;
    185 		}
    186 		break;
    187 	default:
    188 		return ENOTTY;
    189 	}
    190 	return 0;
    191 }
    192 
    193 void
    194 npfattach(int nunits)
    195 {
    196 	/* Nothing */
    197 }
    198 
    199 static int
    200 npf_dev_open(dev_t dev, int flag, int mode, lwp_t *l)
    201 {
    202 	/* Available only for super-user. */
    203 	if (kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FIREWALL,
    204 	    KAUTH_REQ_NETWORK_FIREWALL_FW, NULL, NULL, NULL)) {
    205 		return EPERM;
    206 	}
    207 	return 0;
    208 }
    209 
    210 static int
    211 npf_dev_close(dev_t dev, int flag, int mode, lwp_t *l)
    212 {
    213 	return 0;
    214 }
    215 
    216 static int
    217 npf_stats_export(npf_t *npf, void *data)
    218 {
    219 	uint64_t *fullst, *uptr = *(uint64_t **)data;
    220 	int error;
    221 
    222 	fullst = kmem_alloc(NPF_STATS_SIZE, KM_SLEEP);
    223 	npf_stats(npf, fullst); /* will zero the buffer */
    224 	error = copyout(fullst, uptr, NPF_STATS_SIZE);
    225 	kmem_free(fullst, NPF_STATS_SIZE);
    226 	return error;
    227 }
    228 
    229 static int
    230 npf_dev_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l)
    231 {
    232 	npf_t *npf = npf_getkernctx();
    233 	int error;
    234 
    235 	/* Available only for super-user. */
    236 	if (kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FIREWALL,
    237 	    KAUTH_REQ_NETWORK_FIREWALL_FW, NULL, NULL, NULL)) {
    238 		return EPERM;
    239 	}
    240 
    241 	switch (cmd) {
    242 	case IOC_NPF_TABLE:
    243 		error = npfctl_table(npf, data);
    244 		break;
    245 	case IOC_NPF_RULE:
    246 		error = npfctl_rule(npf, cmd, data);
    247 		break;
    248 	case IOC_NPF_STATS:
    249 		error = npf_stats_export(npf, data);
    250 		break;
    251 	case IOC_NPF_SAVE:
    252 		error = npfctl_save(npf, cmd, data);
    253 		break;
    254 	case IOC_NPF_SWITCH:
    255 		error = npfctl_switch(data);
    256 		break;
    257 	case IOC_NPF_LOAD:
    258 		error = npfctl_load(npf, cmd, data);
    259 		break;
    260 	case IOC_NPF_CONN_LOOKUP:
    261 		error = npfctl_conn_lookup(npf, cmd, data);
    262 		break;
    263 	case IOC_NPF_VERSION:
    264 		*(int *)data = NPF_VERSION;
    265 		error = 0;
    266 		break;
    267 	default:
    268 		error = ENOTTY;
    269 		break;
    270 	}
    271 	return error;
    272 }
    273 
    274 static int
    275 npf_dev_poll(dev_t dev, int events, lwp_t *l)
    276 {
    277 	return ENOTSUP;
    278 }
    279 
    280 static int
    281 npf_dev_read(dev_t dev, struct uio *uio, int flag)
    282 {
    283 	return ENOTSUP;
    284 }
    285 
    286 bool
    287 npf_autounload_p(void)
    288 {
    289 	npf_t *npf = npf_getkernctx();
    290 	return !npf_pfil_registered_p() && npf_default_pass(npf);
    291 }
    292 
    293 /*
    294  * Interface operations.
    295  */
    296 
    297 static const char *
    298 npf_ifop_getname(ifnet_t *ifp)
    299 {
    300 	return ifp->if_xname;
    301 }
    302 
    303 static ifnet_t *
    304 npf_ifop_lookup(const char *name)
    305 {
    306 	return ifunit(name);
    307 }
    308 
    309 static void
    310 npf_ifop_flush(void *arg)
    311 {
    312 	ifnet_t *ifp;
    313 
    314 	KERNEL_LOCK(1, NULL);
    315 	IFNET_LOCK();
    316 	IFNET_WRITER_FOREACH(ifp) {
    317 		ifp->if_pf_kif = arg;
    318 	}
    319 	IFNET_UNLOCK();
    320 	KERNEL_UNLOCK_ONE(NULL);
    321 }
    322 
    323 static void *
    324 npf_ifop_getmeta(const ifnet_t *ifp)
    325 {
    326 	return ifp->if_pf_kif;
    327 }
    328 
    329 static void
    330 npf_ifop_setmeta(ifnet_t *ifp, void *arg)
    331 {
    332 	ifp->if_pf_kif = arg;
    333 }
    334 
    335 #ifdef _KERNEL
    336 
    337 /*
    338  * Wrapper of the main packet handler to pass the kernel NPF context.
    339  */
    340 static int
    341 npfkern_packet_handler(void *arg, struct mbuf **mp, ifnet_t *ifp, int di)
    342 {
    343 	npf_t *npf = npf_getkernctx();
    344 	return npf_packet_handler(npf, mp, ifp, di);
    345 }
    346 
    347 /*
    348  * npf_ifhook: hook handling interface changes.
    349  */
    350 static void
    351 npf_ifhook(void *arg, unsigned long cmd, void *arg2)
    352 {
    353 	npf_t *npf = npf_getkernctx();
    354 	ifnet_t *ifp = arg2;
    355 
    356 	switch (cmd) {
    357 	case PFIL_IFNET_ATTACH:
    358 		npf_ifmap_attach(npf, ifp);
    359 		npf_ifaddr_sync(npf, ifp);
    360 		break;
    361 	case PFIL_IFNET_DETACH:
    362 		npf_ifmap_detach(npf, ifp);
    363 		npf_ifaddr_flush(npf, ifp);
    364 		break;
    365 	}
    366 }
    367 
    368 static void
    369 npf_ifaddrhook(void *arg, u_long cmd, void *arg2)
    370 {
    371 	npf_t *npf = npf_getkernctx();
    372 	struct ifaddr *ifa = arg2;
    373 
    374 	switch (cmd) {
    375 	case SIOCSIFADDR:
    376 	case SIOCAIFADDR:
    377 	case SIOCDIFADDR:
    378 #ifdef INET6
    379 	case SIOCSIFADDR_IN6:
    380 	case SIOCAIFADDR_IN6:
    381 	case SIOCDIFADDR_IN6:
    382 #endif
    383 		break;
    384 	default:
    385 		return;
    386 	}
    387 	npf_ifaddr_sync(npf, ifa->ifa_ifp);
    388 }
    389 
    390 /*
    391  * npf_pfil_register: register pfil(9) hooks.
    392  */
    393 int
    394 npf_pfil_register(bool init)
    395 {
    396 	npf_t *npf = npf_getkernctx();
    397 	int error = 0;
    398 
    399 	mutex_enter(softnet_lock);
    400 	KERNEL_LOCK(1, NULL);
    401 
    402 	/* Init: interface re-config and attach/detach hook. */
    403 	if (!npf_ph_if) {
    404 		npf_ph_if = pfil_head_get(PFIL_TYPE_IFNET, 0);
    405 		if (!npf_ph_if) {
    406 			error = ENOENT;
    407 			goto out;
    408 		}
    409 
    410 		error = pfil_add_ihook(npf_ifhook, NULL,
    411 		    PFIL_IFNET, npf_ph_if);
    412 		KASSERT(error == 0);
    413 
    414 		error = pfil_add_ihook(npf_ifaddrhook, NULL,
    415 		    PFIL_IFADDR, npf_ph_if);
    416 		KASSERT(error == 0);
    417 	}
    418 	if (init) {
    419 		goto out;
    420 	}
    421 
    422 	/* Check if pfil hooks are not already registered. */
    423 	if (pfil_registered) {
    424 		error = EEXIST;
    425 		goto out;
    426 	}
    427 
    428 	/* Capture points of the activity in the IP layer. */
    429 	npf_ph_inet = pfil_head_get(PFIL_TYPE_AF, (void *)AF_INET);
    430 	npf_ph_inet6 = pfil_head_get(PFIL_TYPE_AF, (void *)AF_INET6);
    431 	if (!npf_ph_inet && !npf_ph_inet6) {
    432 		error = ENOENT;
    433 		goto out;
    434 	}
    435 
    436 	/* Packet IN/OUT handlers for IP layer. */
    437 	if (npf_ph_inet) {
    438 		error = pfil_add_hook(npfkern_packet_handler, npf,
    439 		    PFIL_ALL, npf_ph_inet);
    440 		KASSERT(error == 0);
    441 	}
    442 	if (npf_ph_inet6) {
    443 		error = pfil_add_hook(npfkern_packet_handler, npf,
    444 		    PFIL_ALL, npf_ph_inet6);
    445 		KASSERT(error == 0);
    446 	}
    447 
    448 	/*
    449 	 * It is necessary to re-sync all/any interface address tables,
    450 	 * since we did not listen for any changes.
    451 	 */
    452 	npf_ifaddr_syncall(npf);
    453 	pfil_registered = true;
    454 out:
    455 	KERNEL_UNLOCK_ONE(NULL);
    456 	mutex_exit(softnet_lock);
    457 
    458 	return error;
    459 }
    460 
    461 /*
    462  * npf_pfil_unregister: unregister pfil(9) hooks.
    463  */
    464 void
    465 npf_pfil_unregister(bool fini)
    466 {
    467 	npf_t *npf = npf_getkernctx();
    468 
    469 	mutex_enter(softnet_lock);
    470 	KERNEL_LOCK(1, NULL);
    471 
    472 	if (fini && npf_ph_if) {
    473 		(void)pfil_remove_ihook(npf_ifhook, NULL,
    474 		    PFIL_IFNET, npf_ph_if);
    475 		(void)pfil_remove_ihook(npf_ifaddrhook, NULL,
    476 		    PFIL_IFADDR, npf_ph_if);
    477 	}
    478 	if (npf_ph_inet) {
    479 		(void)pfil_remove_hook(npfkern_packet_handler, npf,
    480 		    PFIL_ALL, npf_ph_inet);
    481 	}
    482 	if (npf_ph_inet6) {
    483 		(void)pfil_remove_hook(npfkern_packet_handler, npf,
    484 		    PFIL_ALL, npf_ph_inet6);
    485 	}
    486 	pfil_registered = false;
    487 
    488 	KERNEL_UNLOCK_ONE(NULL);
    489 	mutex_exit(softnet_lock);
    490 }
    491 
    492 bool
    493 npf_pfil_registered_p(void)
    494 {
    495 	return pfil_registered;
    496 }
    497 #endif
    498