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npf_if.c revision 1.2 
      1 /*	$NetBSD: npf_if.c,v 1.2 2013/11/11 15:28:37 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by 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 network interface handling module.
     34  *
     35  * NPF uses its own interface IDs (npf-if-id).  When NPF configuration is
     36  * (re)loaded, each required interface name is registered and a matching
     37  * network interface gets an ID assigned.  If an interface is not present,
     38  * it gets an ID on attach.  Any other interfaces get INACTIVE_ID.
     39  *
     40  * The IDs are mapped synchronously based on interface events which are
     41  * monitored using pfil(9) hooks.
     42  */
     43 
     44 #include <sys/cdefs.h>
     45 __KERNEL_RCSID(0, "$NetBSD: npf_if.c,v 1.2 2013/11/11 15:28:37 martin Exp $");
     46 
     47 #ifdef _KERNEL_OPT
     48 #include "pf.h"
     49 #if NPF > 0
     50 #error "NPF and PF are mutually exclusive; please select one"
     51 #endif
     52 #endif
     53 
     54 #include <sys/param.h>
     55 #include <sys/types.h>
     56 #include <sys/kmem.h>
     57 
     58 #include <net/if.h>
     59 
     60 #include "npf_impl.h"
     61 
     62 #define	INACTIVE_ID	((u_int)-1)
     63 
     64 typedef struct {
     65 	char		n_ifname[IFNAMSIZ];
     66 } npf_ifmap_t;
     67 
     68 static npf_ifmap_t	npf_ifmap[NPF_MAX_IFMAP]	__read_mostly;
     69 static u_int		npf_ifmap_cnt			__read_mostly;
     70 
     71 /*
     72  * NOTE: IDs start from 1.  Zero is reseved for "no interface" and
     73  * (unsigned)-1 for "inactive interface".  Therefore, an interface
     74  * can have either INACTIVE_ID or non-zero ID.
     75  */
     76 
     77 static u_int
     78 npf_ifmap_new(void)
     79 {
     80 	KASSERT(npf_config_locked_p());
     81 
     82 	for (u_int i = 0; i < npf_ifmap_cnt; i++)
     83 		if (npf_ifmap[i].n_ifname[0] == '\0')
     84 			return i + 1;
     85 
     86 	if (npf_ifmap_cnt == NPF_MAX_IFMAP) {
     87 		printf("npf_ifmap_new: out of slots; bump NPF_MAX_IFMAP\n");
     88 		return INACTIVE_ID;
     89 	}
     90 	return ++npf_ifmap_cnt;
     91 }
     92 
     93 static u_int
     94 npf_ifmap_lookup(const char *ifname)
     95 {
     96 	KASSERT(npf_config_locked_p());
     97 
     98 	for (u_int i = 0; i < npf_ifmap_cnt; i++) {
     99 		npf_ifmap_t *nim = &npf_ifmap[i];
    100 
    101 		if (nim->n_ifname[0] && strcmp(nim->n_ifname, ifname) == 0)
    102 			return i + 1;
    103 	}
    104 	return INACTIVE_ID;
    105 }
    106 
    107 u_int
    108 npf_ifmap_register(const char *ifname)
    109 {
    110 	npf_ifmap_t *nim;
    111 	ifnet_t *ifp;
    112 	u_int i;
    113 
    114 	npf_config_enter();
    115 	if ((i = npf_ifmap_lookup(ifname)) != INACTIVE_ID) {
    116 		goto out;
    117 	}
    118 	if ((i = npf_ifmap_new()) == INACTIVE_ID) {
    119 		i = INACTIVE_ID;
    120 		goto out;
    121 	}
    122 	nim = &npf_ifmap[i - 1];
    123 	strlcpy(nim->n_ifname, ifname, IFNAMSIZ);
    124 
    125 	KERNEL_LOCK(1, NULL);
    126 	if ((ifp = ifunit(ifname)) != NULL) {
    127 		ifp->if_pf_kif = (void *)(uintptr_t)i;
    128 	}
    129 	KERNEL_UNLOCK_ONE(NULL);
    130 out:
    131 	npf_config_exit();
    132 	return i;
    133 }
    134 
    135 void
    136 npf_ifmap_flush(void)
    137 {
    138 	ifnet_t *ifp;
    139 
    140 	KASSERT(npf_config_locked_p());
    141 
    142 	for (u_int i = 0; i < npf_ifmap_cnt; i++) {
    143 		npf_ifmap[i].n_ifname[0] = '\0';
    144 	}
    145 	npf_ifmap_cnt = 0;
    146 
    147 	KERNEL_LOCK(1, NULL);
    148 	IFNET_FOREACH(ifp) {
    149 		ifp->if_pf_kif = (void *)(uintptr_t)INACTIVE_ID;
    150 	}
    151 	KERNEL_UNLOCK_ONE(NULL);
    152 }
    153 
    154 u_int
    155 npf_ifmap_id(const ifnet_t *ifp)
    156 {
    157 	const u_int i = (uintptr_t)ifp->if_pf_kif;
    158 
    159 	KASSERT(i == INACTIVE_ID || (i > 0 && i <= npf_ifmap_cnt));
    160 	return i;
    161 }
    162 
    163 void
    164 npf_ifmap_attach(ifnet_t *ifp)
    165 {
    166 	npf_config_enter();
    167 	ifp->if_pf_kif = (void *)(uintptr_t)npf_ifmap_lookup(ifp->if_xname);
    168 	npf_config_exit();
    169 }
    170 
    171 void
    172 npf_ifmap_detach(ifnet_t *ifp)
    173 {
    174 	npf_config_enter();
    175 	ifp->if_pf_kif = (void *)(uintptr_t)INACTIVE_ID; /* diagnostic */
    176 	npf_config_exit();
    177 }
    178