uipc_accf.c

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    1 /*      $NetBSD: uipc_accf.c,v 1.13 2014/02/25 18:30:11 pooka Exp $     */
    2 
    3 /*-
    4  * Copyright (c) 2008 The NetBSD Foundation, Inc.
    5  * All rights reserved.
    6  *
    7  * This code is derived from software developed for The NetBSD Foundation
    8  * by Andrew Doran.
    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  * Copyright (c) 2000 Paycounter, Inc.
   34  * Copyright (c) 2005 Robert N. M. Watson
   35  * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
   36  * All rights reserved.
   37  *
   38  * Redistribution and use in source and binary forms, with or without
   39  * modification, are permitted provided that the following conditions
   40  * are met:
   41  * 1. Redistributions of source code must retain the above copyright
   42  *    notice, this list of conditions and the following disclaimer.
   43  * 2. Redistributions in binary form must reproduce the above copyright
   44  *    notice, this list of conditions and the following disclaimer in the
   45  *    documentation and/or other materials provided with the distribution.
   46  *
   47  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   57  * SUCH DAMAGE.
   58  */
   59 
   60 #include <sys/cdefs.h>
   61 __KERNEL_RCSID(0, "$NetBSD: uipc_accf.c,v 1.13 2014/02/25 18:30:11 pooka Exp $");
   62 
   63 #define ACCEPT_FILTER_MOD
   64 
   65 #include <sys/param.h>
   66 #include <sys/systm.h>
   67 #include <sys/domain.h>
   68 #include <sys/kernel.h>
   69 #include <sys/lock.h>
   70 #include <sys/kmem.h>
   71 #include <sys/mbuf.h>
   72 #include <sys/rwlock.h>
   73 #include <sys/protosw.h>
   74 #include <sys/sysctl.h>
   75 #include <sys/socket.h>
   76 #include <sys/socketvar.h>
   77 #include <sys/queue.h>
   78 #include <sys/once.h>
   79 #include <sys/atomic.h>
   80 #include <sys/module.h>
   81 
   82 static krwlock_t accept_filter_lock;
   83 
   84 static LIST_HEAD(, accept_filter) accept_filtlsthd =
   85     LIST_HEAD_INITIALIZER(&accept_filtlsthd);
   86 
   87 /*
   88  * Names of Accept filter sysctl objects
   89  */
   90 static struct sysctllog *ctllog;
   91 static void
   92 sysctl_net_inet_accf_setup(void)
   93 {
   94 
   95         sysctl_createv(&ctllog, 0, NULL, NULL,
   96                        CTLFLAG_PERMANENT,
   97                        CTLTYPE_NODE, "inet", NULL,
   98                        NULL, 0, NULL, 0,
   99                        CTL_NET, PF_INET, CTL_EOL);
  100         sysctl_createv(&ctllog, 0, NULL, NULL,
  101                        CTLFLAG_PERMANENT,
  102                        CTLTYPE_NODE, "accf",
  103                        SYSCTL_DESCR("Accept filters"),
  104                        NULL, 0, NULL, 0,
  105                        CTL_NET, PF_INET, SO_ACCEPTFILTER, CTL_EOL);
  106 }
  107 
  108 int
  109 accept_filt_add(struct accept_filter *filt)
  110 {
  111         struct accept_filter *p;
  112 
  113         accept_filter_init();
  114 
  115         rw_enter(&accept_filter_lock, RW_WRITER);
  116         LIST_FOREACH(p, &accept_filtlsthd, accf_next) {
  117                 if (strcmp(p->accf_name, filt->accf_name) == 0)  {
  118                         rw_exit(&accept_filter_lock);
  119                         return EEXIST;
  120                 }
  121         }                               
  122         LIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next);
  123         rw_exit(&accept_filter_lock);
  124 
  125         return 0;
  126 }
  127 
  128 int
  129 accept_filt_del(struct accept_filter *p)
  130 {
  131 
  132         rw_enter(&accept_filter_lock, RW_WRITER);
  133         if (p->accf_refcnt != 0) {
  134                 rw_exit(&accept_filter_lock);
  135                 return EBUSY;
  136         }
  137         LIST_REMOVE(p, accf_next);
  138         rw_exit(&accept_filter_lock);
  139 
  140         return 0;
  141 }
  142 
  143 struct accept_filter *
  144 accept_filt_get(char *name)
  145 {
  146         struct accept_filter *p;
  147         char buf[32];
  148         u_int gen;
  149 
  150         do {
  151                 rw_enter(&accept_filter_lock, RW_READER);
  152                 LIST_FOREACH(p, &accept_filtlsthd, accf_next) {
  153                         if (strcmp(p->accf_name, name) == 0) {
  154                                 atomic_inc_uint(&p->accf_refcnt);
  155                                 break;
  156                         }
  157                 }
  158                 rw_exit(&accept_filter_lock);
  159                 if (p != NULL) {
  160                         break;
  161                 }
  162                 /* Try to autoload a module to satisfy the request. */
  163                 strcpy(buf, "accf_");
  164                 strlcat(buf, name, sizeof(buf));
  165                 gen = module_gen;
  166                 (void)module_autoload(buf, MODULE_CLASS_ANY);
  167         } while (gen != module_gen);
  168 
  169         return p;
  170 }
  171 
  172 /*
  173  * Accept filter initialization routine.
  174  * This should be called only once.
  175  */
  176 
  177 static int
  178 accept_filter_init0(void)
  179 {
  180 
  181         rw_init(&accept_filter_lock);
  182         sysctl_net_inet_accf_setup();
  183 
  184         return 0;
  185 }
  186 
  187 /*
  188  * Initialization routine: This can also be replaced with 
  189  * accept_filt_generic_mod_event for attaching new accept filter.
  190  */
  191 
  192 void
  193 accept_filter_init(void)
  194 {
  195         static ONCE_DECL(accept_filter_init_once);
  196 
  197         RUN_ONCE(&accept_filter_init_once, accept_filter_init0);
  198 }
  199 
  200 int
  201 accept_filt_getopt(struct socket *so, struct sockopt *sopt)
  202 {
  203         struct accept_filter_arg afa;
  204         int error;
  205 
  206         KASSERT(solocked(so));
  207 
  208         if ((so->so_options & SO_ACCEPTCONN) == 0) {
  209                 error = EINVAL;
  210                 goto out;
  211         }
  212         if ((so->so_options & SO_ACCEPTFILTER) == 0) {
  213                 error = EINVAL;
  214                 goto out;
  215         }
  216 
  217         memset(&afa, 0, sizeof(afa));
  218         strcpy(afa.af_name, so->so_accf->so_accept_filter->accf_name);
  219         if (so->so_accf->so_accept_filter_str != NULL)
  220                 strcpy(afa.af_arg, so->so_accf->so_accept_filter_str);
  221         error = sockopt_set(sopt, &afa, sizeof(afa));
  222 out:
  223         return error;
  224 }
  225 
  226 /*
  227  * Simple delete case, with socket locked.
  228  */
  229 int
  230 accept_filt_clear(struct socket *so)
  231 {
  232         struct accept_filter_arg afa;
  233         struct accept_filter *afp;
  234         struct socket *so2, *next;
  235         struct so_accf *af;
  236 
  237         KASSERT(solocked(so));
  238 
  239         if ((so->so_options & SO_ACCEPTCONN) == 0) {
  240                 return EINVAL;
  241         }
  242         if (so->so_accf != NULL) {
  243                 /* Break in-flight processing. */
  244                 for (so2 = TAILQ_FIRST(&so->so_q0); so2 != NULL; so2 = next) {
  245                         next = TAILQ_NEXT(so2, so_qe);
  246                         if (so2->so_upcall == NULL) {
  247                                 continue;
  248                         }
  249                         so2->so_upcall = NULL;
  250                         so2->so_upcallarg = NULL;
  251                         so2->so_options &= ~SO_ACCEPTFILTER;
  252                         so2->so_rcv.sb_flags &= ~SB_UPCALL;
  253                         soisconnected(so2);
  254                 }
  255                 af = so->so_accf;
  256                 afp = af->so_accept_filter;
  257                 if (afp != NULL && afp->accf_destroy != NULL) {
  258                         (*afp->accf_destroy)(so);
  259                 }
  260                 if (af->so_accept_filter_str != NULL) {
  261                         kmem_free(af->so_accept_filter_str,
  262                             sizeof(afa.af_name));
  263                 }
  264                 kmem_free(af, sizeof(*af));
  265                 so->so_accf = NULL;
  266                 atomic_dec_uint(&afp->accf_refcnt);
  267         }
  268         so->so_options &= ~SO_ACCEPTFILTER;
  269         return 0;
  270 }
  271 
  272 /*
  273  * setsockopt() for accept filters.  Called with the socket unlocked,
  274  * will always return it locked.
  275  */
  276 int
  277 accept_filt_setopt(struct socket *so, const struct sockopt *sopt)
  278 {
  279         struct accept_filter_arg afa;
  280         struct accept_filter *afp;
  281         struct so_accf *newaf;
  282         int error;
  283 
  284         accept_filter_init();
  285 
  286         if (sopt == NULL || sopt->sopt_size == 0) {
  287                 solock(so);
  288                 return accept_filt_clear(so);
  289         }
  290 
  291         /*
  292          * Pre-allocate any memory we may need later to avoid blocking at
  293          * untimely moments.  This does not optimize for invalid arguments.
  294          */
  295         error = sockopt_get(sopt, &afa, sizeof(afa));
  296         if (error) {
  297                 solock(so);
  298                 return error;
  299         }
  300         afa.af_name[sizeof(afa.af_name)-1] = '\0';
  301         afa.af_arg[sizeof(afa.af_arg)-1] = '\0';
  302         afp = accept_filt_get(afa.af_name);
  303         if (afp == NULL) {
  304                 solock(so);
  305                 return ENOENT;
  306         }
  307         /*
  308          * Allocate the new accept filter instance storage.  We may
  309          * have to free it again later if we fail to attach it.  If
  310          * attached properly, 'newaf' is NULLed to avoid a free()
  311          * while in use.
  312          */
  313         newaf = kmem_zalloc(sizeof(*newaf), KM_SLEEP);
  314         if (afp->accf_create != NULL && afa.af_name[0] != '\0') {
  315                 /*
  316                  * FreeBSD did a variable-size allocation here
  317                  * with the actual string length from afa.af_name
  318                  * but it is so short, why bother tracking it?
  319                  * XXX as others have noted, this is an API mistake;
  320                  * XXX accept_filter_arg should have a mandatory namelen.
  321                  * XXX (but it's a bit too late to fix that now)
  322                  */
  323                 newaf->so_accept_filter_str =
  324                     kmem_alloc(sizeof(afa.af_name), KM_SLEEP);
  325                 strcpy(newaf->so_accept_filter_str, afa.af_name);
  326         }
  327 
  328         /*
  329          * Require a listen socket; don't try to replace an existing filter
  330          * without first removing it.
  331          */
  332         solock(so);
  333         if ((so->so_options & SO_ACCEPTCONN) == 0 || so->so_accf != NULL) {
  334                 error = EINVAL;
  335                 goto out;
  336         }
  337 
  338         /*
  339          * Invoke the accf_create() method of the filter if required.  The
  340          * socket lock is held over this call, so create methods for filters
  341          * shouldn't block.
  342          */
  343         if (afp->accf_create != NULL) {
  344                 newaf->so_accept_filter_arg =
  345                     (*afp->accf_create)(so, afa.af_arg);
  346                 if (newaf->so_accept_filter_arg == NULL) {
  347                         error = EINVAL;
  348                         goto out;
  349                 }
  350         }
  351         newaf->so_accept_filter = afp;
  352         so->so_accf = newaf;
  353         so->so_options |= SO_ACCEPTFILTER;
  354         newaf = NULL;
  355 out:
  356         if (newaf != NULL) {
  357                 if (newaf->so_accept_filter_str != NULL)
  358                         kmem_free(newaf->so_accept_filter_str,
  359                             sizeof(afa.af_name));
  360                 kmem_free(newaf, sizeof(*newaf));
  361                 atomic_dec_uint(&afp->accf_refcnt);
  362         }
  363         return error;
  364 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/uipc_accf.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/uipc_accf.c
