sys/kern/uipc_accf.c

   1 /*
   2  * Copyright (c) 2000 Paycounter, Inc.
   3  * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@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  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  *      $FreeBSD: src/sys/kern/uipc_accf.c,v 1.2.2.2 2000/09/20 21:19:21 ps Exp $
  28  *      $DragonFly: src/sys/kern/uipc_accf.c,v 1.3 2005/06/06 15:02:28 dillon Exp $
  29  */
  30
  31 #define ACCEPT_FILTER_MOD
  32
  33 #include "opt_param.h"
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/domain.h>
  37 #include <sys/kernel.h>
  38 #include <sys/proc.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mbuf.h>
  41 #include <sys/protosw.h>
  42 #include <sys/sysctl.h>
  43 #include <sys/socket.h>
  44 #include <sys/socketvar.h>
  45 #include <sys/queue.h>
  46 #include <sys/thread2.h>
  47
  48 static SLIST_HEAD(, accept_filter) accept_filtlsthd =
  49         SLIST_HEAD_INITIALIZER(&accept_filtlsthd);
  50
  51 MALLOC_DEFINE(M_ACCF, "accf", "accept filter data");
  52
  53 static int unloadable = 0;
  54
  55 SYSCTL_DECL(_net_inet); /* XXX: some header should do this for me */
  56 SYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters");
  57 SYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0,
  58         "Allow unload of accept filters (not recommended)");
  59
  60 /*
  61  * must be passed a malloc'd structure so we don't explode if the kld
  62  * is unloaded, we leak the struct on deallocation to deal with this,
  63  * but if a filter is loaded with the same name as a leaked one we re-use
  64  * the entry.
  65  */
  66 int
  67 accept_filt_add(struct accept_filter *filt)
  68 {
  69         struct accept_filter *p;
  70
  71         SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
  72                 if (strcmp(p->accf_name, filt->accf_name) == 0)  {
  73                         if (p->accf_callback != NULL) {
  74                                 return (EEXIST);
  75                         } else {
  76                                 p->accf_callback = filt->accf_callback;
  77                                 FREE(filt, M_ACCF);
  78                                 return (0);
  79                         }
  80                 }
  81
  82         if (p == NULL)
  83                 SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
  84         return (0);
  85 }
  86
  87 int
  88 accept_filt_del(char *name)
  89 {
  90         struct accept_filter *p;
  91
  92         p = accept_filt_get(name);
  93         if (p == NULL)
  94                 return (ENOENT);
  95
  96         p->accf_callback = NULL;
  97         return (0);
  98 }
  99
 100 struct accept_filter *
 101 accept_filt_get(char *name)
 102 {
 103         struct accept_filter *p;
 104
 105         SLIST_FOREACH(p, &accept_filtlsthd, accf_next)
 106                 if (strcmp(p->accf_name, name) == 0)
 107                         return (p);
 108
 109         return (NULL);
 110 }
 111
 112 int
 113 accept_filt_generic_mod_event(module_t mod, int event, void *data)
 114 {
 115         struct accept_filter *p;
 116         struct accept_filter *accfp = (struct accept_filter *) data;
 117         int     error;
 118
 119         switch (event) {
 120         case MOD_LOAD:
 121                 MALLOC(p, struct accept_filter *, sizeof(*p), M_ACCF, M_WAITOK);
 122                 bcopy(accfp, p, sizeof(*p));
 123                 crit_enter();
 124                 error = accept_filt_add(p);
 125                 crit_exit();
 126                 break;
 127
 128         case MOD_UNLOAD:
 129                 /*
 130                  * Do not support unloading yet. we don't keep track of refcounts
 131                  * and unloading an accept filter callback and then having it called
 132                  * is a bad thing.  A simple fix would be to track the refcount
 133                  * in the struct accept_filter.
 134                  */
 135                 if (unloadable != 0) {
 136                         crit_enter();
 137                         error = accept_filt_del(accfp->accf_name);
 138                         crit_exit();
 139                 } else
 140                         error = EOPNOTSUPP;
 141                 break;
 142
 143         case MOD_SHUTDOWN:
 144                 error = 0;
 145                 break;
 146
 147         default:
 148                 error = EOPNOTSUPP;
 149                 break;
 150         }
 151
 152         return (error);
 153 }