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npf.c revision 1.8 
      1 /*	$NetBSD: npf.c,v 1.8 2012/02/20 00:18:19 rmind Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2009-2010 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 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: npf.c,v 1.8 2012/02/20 00:18:19 rmind Exp $");
     38 
     39 #include <sys/param.h>
     40 #include <sys/types.h>
     41 
     42 #include <sys/atomic.h>
     43 #include <sys/conf.h>
     44 #include <sys/kauth.h>
     45 #include <sys/kmem.h>
     46 #include <sys/lwp.h>
     47 #include <sys/module.h>
     48 #include <sys/percpu.h>
     49 #include <sys/rwlock.h>
     50 #include <sys/socketvar.h>
     51 #include <sys/uio.h>
     52 
     53 #include "npf_impl.h"
     54 
     55 /*
     56  * Module and device structures.
     57  */
     58 MODULE(MODULE_CLASS_DRIVER, npf, NULL);
     59 
     60 void		npfattach(int);
     61 
     62 static int	npf_fini(void);
     63 static int	npf_dev_open(dev_t, int, int, lwp_t *);
     64 static int	npf_dev_close(dev_t, int, int, lwp_t *);
     65 static int	npf_dev_ioctl(dev_t, u_long, void *, int, lwp_t *);
     66 static int	npf_dev_poll(dev_t, int, lwp_t *);
     67 static int	npf_dev_read(dev_t, struct uio *, int);
     68 
     69 typedef struct {
     70 	npf_ruleset_t *		n_rules;
     71 	npf_tableset_t *	n_tables;
     72 	npf_ruleset_t *		n_nat_rules;
     73 	bool			n_default_pass;
     74 } npf_core_t;
     75 
     76 static void	npf_core_destroy(npf_core_t *);
     77 static int	npfctl_stats(void *);
     78 
     79 static krwlock_t		npf_lock		__cacheline_aligned;
     80 static npf_core_t *		npf_core		__cacheline_aligned;
     81 static percpu_t *		npf_stats_percpu	__read_mostly;
     82 
     83 const struct cdevsw npf_cdevsw = {
     84 	npf_dev_open, npf_dev_close, npf_dev_read, nowrite, npf_dev_ioctl,
     85 	nostop, notty, npf_dev_poll, nommap, nokqfilter, D_OTHER | D_MPSAFE
     86 };
     87 
     88 static int
     89 npf_init(void)
     90 {
     91 #ifdef _MODULE
     92 	devmajor_t bmajor = NODEVMAJOR, cmajor = NODEVMAJOR;
     93 #endif
     94 	npf_ruleset_t *rset, *nset;
     95 	npf_tableset_t *tset;
     96 	int error = 0;
     97 
     98 	rw_init(&npf_lock);
     99 	npf_stats_percpu = percpu_alloc(NPF_STATS_SIZE);
    100 	npf_tableset_sysinit();
    101 	npf_session_sysinit();
    102 	npf_nat_sysinit();
    103 	npf_alg_sysinit();
    104 	npflogattach(1);
    105 
    106 	/* Load empty configuration. */
    107 	rset = npf_ruleset_create();
    108 	tset = npf_tableset_create();
    109 	nset = npf_ruleset_create();
    110 	npf_reload(rset, tset, nset, true);
    111 	KASSERT(npf_core != NULL);
    112 
    113 #ifdef _MODULE
    114 	/* Attach /dev/npf device. */
    115 	error = devsw_attach("npf", NULL, &bmajor, &npf_cdevsw, &cmajor);
    116 	if (error) {
    117 		/* It will call devsw_detach(), which is safe. */
    118 		(void)npf_fini();
    119 	}
    120 #endif
    121 	return error;
    122 }
    123 
    124 static int
    125 npf_fini(void)
    126 {
    127 
    128 	/*
    129 	 * At first, detach device, remove pfil hooks and unload existing
    130 	 * configuration, destroy structures.
    131 	 */
    132 #ifdef _MODULE
    133 	devsw_detach(NULL, &npf_cdevsw);
    134 #endif
    135 	npf_unregister_pfil();
    136 	npf_core_destroy(npf_core);
    137 	npflogdetach();
    138 
    139 	/* Note: order is particular. */
    140 	npf_nat_sysfini();
    141 	npf_alg_sysfini();
    142 	npf_session_sysfini();
    143 	npf_tableset_sysfini();
    144 	percpu_free(npf_stats_percpu, NPF_STATS_SIZE);
    145 	rw_destroy(&npf_lock);
    146 
    147 	return 0;
    148 }
    149 
    150 /*
    151  * Module interface.
    152  */
    153 static int
    154 npf_modcmd(modcmd_t cmd, void *arg)
    155 {
    156 
    157 	switch (cmd) {
    158 	case MODULE_CMD_INIT:
    159 		return npf_init();
    160 	case MODULE_CMD_FINI:
    161 		return npf_fini();
    162 	default:
    163 		return ENOTTY;
    164 	}
    165 	return 0;
    166 }
    167 
    168 void
    169 npfattach(int nunits)
    170 {
    171 
    172 	/* Void. */
    173 }
    174 
    175 static int
    176 npf_dev_open(dev_t dev, int flag, int mode, lwp_t *l)
    177 {
    178 
    179 	/* Available only for super-user. */
    180 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, NULL)) {
    181 		return EPERM;
    182 	}
    183 	return 0;
    184 }
    185 
    186 static int
    187 npf_dev_close(dev_t dev, int flag, int mode, lwp_t *l)
    188 {
    189 
    190 	return 0;
    191 }
    192 
    193 static int
    194 npf_dev_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l)
    195 {
    196 	int error;
    197 
    198 	/* Available only for super-user. */
    199 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, NULL)) {
    200 		return EPERM;
    201 	}
    202 
    203 	switch (cmd) {
    204 	case IOC_NPF_VERSION:
    205 		*(int *)data = NPF_VERSION;
    206 		error = 0;
    207 		break;
    208 	case IOC_NPF_SWITCH:
    209 		error = npfctl_switch(data);
    210 		break;
    211 	case IOC_NPF_RELOAD:
    212 		error = npfctl_reload(cmd, data);
    213 		break;
    214 	case IOC_NPF_TABLE:
    215 		error = npfctl_table(data);
    216 		break;
    217 	case IOC_NPF_STATS:
    218 		error = npfctl_stats(data);
    219 		break;
    220 	case IOC_NPF_SESSIONS_SAVE:
    221 		error = npfctl_sessions_save(cmd, data);
    222 		break;
    223 	case IOC_NPF_SESSIONS_LOAD:
    224 		error = npfctl_sessions_load(cmd, data);
    225 		break;
    226 	case IOC_NPF_UPDATE_RULE:
    227 		error = npfctl_update_rule(cmd, data);
    228 		break;
    229 	default:
    230 		error = ENOTTY;
    231 		break;
    232 	}
    233 	return error;
    234 }
    235 
    236 static int
    237 npf_dev_poll(dev_t dev, int events, lwp_t *l)
    238 {
    239 
    240 	return ENOTSUP;
    241 }
    242 
    243 static int
    244 npf_dev_read(dev_t dev, struct uio *uio, int flag)
    245 {
    246 
    247 	return ENOTSUP;
    248 }
    249 
    250 /*
    251  * NPF core loading/reloading/unloading mechanism.
    252  */
    253 
    254 static void
    255 npf_core_destroy(npf_core_t *nc)
    256 {
    257 
    258 	npf_ruleset_destroy(nc->n_rules);
    259 	npf_ruleset_destroy(nc->n_nat_rules);
    260 	npf_tableset_destroy(nc->n_tables);
    261 	kmem_free(nc, sizeof(npf_core_t));
    262 }
    263 
    264 /*
    265  * npf_reload: atomically load new ruleset, tableset and NAT policies.
    266  * Then destroy old (unloaded) structures.
    267  */
    268 void
    269 npf_reload(npf_ruleset_t *rset, npf_tableset_t *tset, npf_ruleset_t *nset,
    270     bool flush)
    271 {
    272 	npf_core_t *nc, *onc;
    273 
    274 	/* Setup a new core structure. */
    275 	nc = kmem_zalloc(sizeof(npf_core_t), KM_SLEEP);
    276 	nc->n_default_pass = flush;
    277 	nc->n_rules = rset;
    278 	nc->n_tables = tset;
    279 	nc->n_nat_rules = nset;
    280 
    281 	/* Lock and load the core structure. */
    282 	rw_enter(&npf_lock, RW_WRITER);
    283 	onc = atomic_swap_ptr(&npf_core, nc);
    284 	if (onc) {
    285 		/* Reload only necessary NAT policies. */
    286 		npf_ruleset_natreload(nset, onc->n_nat_rules);
    287 	}
    288 	/* Unlock.  Everything goes "live" now. */
    289 	rw_exit(&npf_lock);
    290 
    291 	if (onc) {
    292 		/* Destroy unloaded structures. */
    293 		npf_core_destroy(onc);
    294 	}
    295 }
    296 
    297 void
    298 npf_core_enter(void)
    299 {
    300 	rw_enter(&npf_lock, RW_READER);
    301 }
    302 
    303 npf_ruleset_t *
    304 npf_core_ruleset(void)
    305 {
    306 	KASSERT(rw_lock_held(&npf_lock));
    307 	return npf_core->n_rules;
    308 }
    309 
    310 npf_ruleset_t *
    311 npf_core_natset(void)
    312 {
    313 	KASSERT(rw_lock_held(&npf_lock));
    314 	return npf_core->n_nat_rules;
    315 }
    316 
    317 npf_tableset_t *
    318 npf_core_tableset(void)
    319 {
    320 	KASSERT(rw_lock_held(&npf_lock));
    321 	return npf_core->n_tables;
    322 }
    323 
    324 void
    325 npf_core_exit(void)
    326 {
    327 	rw_exit(&npf_lock);
    328 }
    329 
    330 bool
    331 npf_core_locked(void)
    332 {
    333 	return rw_lock_held(&npf_lock);
    334 }
    335 
    336 bool
    337 npf_default_pass(void)
    338 {
    339 	KASSERT(rw_lock_held(&npf_lock));
    340 	return npf_core->n_default_pass;
    341 }
    342 
    343 /*
    344  * NPF statistics interface.
    345  */
    346 
    347 void
    348 npf_stats_inc(npf_stats_t st)
    349 {
    350 	uint64_t *stats = percpu_getref(npf_stats_percpu);
    351 	stats[st]++;
    352 	percpu_putref(npf_stats_percpu);
    353 }
    354 
    355 void
    356 npf_stats_dec(npf_stats_t st)
    357 {
    358 	uint64_t *stats = percpu_getref(npf_stats_percpu);
    359 	stats[st]--;
    360 	percpu_putref(npf_stats_percpu);
    361 }
    362 
    363 static void
    364 npf_stats_collect(void *mem, void *arg, struct cpu_info *ci)
    365 {
    366 	uint64_t *percpu_stats = mem, *full_stats = arg;
    367 	int i;
    368 
    369 	for (i = 0; i < NPF_STATS_COUNT; i++) {
    370 		full_stats[i] += percpu_stats[i];
    371 	}
    372 }
    373 
    374 /*
    375  * npfctl_stats: export collected statistics.
    376  */
    377 static int
    378 npfctl_stats(void *data)
    379 {
    380 	uint64_t *fullst, *uptr = *(uint64_t **)data;
    381 	int error;
    382 
    383 	fullst = kmem_zalloc(NPF_STATS_SIZE, KM_SLEEP);
    384 	percpu_foreach(npf_stats_percpu, npf_stats_collect, fullst);
    385 	error = copyout(fullst, uptr, NPF_STATS_SIZE);
    386 	kmem_free(fullst, NPF_STATS_SIZE);
    387 	return error;
    388 }
    389