ng_ipfw.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright 2005, Gleb Smirnoff <glebius@FreeBSD.org>
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  *
   28  * $FreeBSD$
   29  */
   30 
   31 #include "opt_inet.h"
   32 #include "opt_inet6.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/kernel.h>
   37 #include <sys/lock.h>
   38 #include <sys/mbuf.h>
   39 #include <sys/malloc.h>
   40 #include <sys/ctype.h>
   41 #include <sys/errno.h>
   42 #include <sys/rwlock.h>
   43 #include <sys/socket.h>
   44 #include <sys/syslog.h>
   45 
   46 #include <net/if.h>
   47 #include <net/if_var.h>
   48 
   49 #include <netinet/in.h>
   50 #include <netinet/in_systm.h>
   51 #include <netinet/in_var.h>
   52 #include <netinet/ip_var.h>
   53 #include <netinet/ip_fw.h>
   54 #include <netinet/ip.h>
   55 #include <netinet/ip6.h>
   56 #include <netinet6/ip6_var.h>
   57 
   58 #include <netpfil/ipfw/ip_fw_private.h>
   59 
   60 #include <netgraph/ng_message.h>
   61 #include <netgraph/ng_parse.h>
   62 #include <netgraph/ng_ipfw.h>
   63 #include <netgraph/netgraph.h>
   64 
   65 static int              ng_ipfw_mod_event(module_t mod, int event, void *data);
   66 static ng_constructor_t ng_ipfw_constructor;
   67 static ng_shutdown_t    ng_ipfw_shutdown;
   68 static ng_newhook_t     ng_ipfw_newhook;
   69 static ng_connect_t     ng_ipfw_connect;
   70 static ng_findhook_t    ng_ipfw_findhook;
   71 static ng_rcvdata_t     ng_ipfw_rcvdata;
   72 static ng_disconnect_t  ng_ipfw_disconnect;
   73 
   74 static hook_p           ng_ipfw_findhook1(node_p, u_int16_t );
   75 static int      ng_ipfw_input(struct mbuf **, struct ip_fw_args *, bool);
   76 
   77 /* We have only one node */
   78 static node_p   fw_node;
   79 
   80 /* Netgraph node type descriptor */
   81 static struct ng_type ng_ipfw_typestruct = {
   82         .version =      NG_ABI_VERSION,
   83         .name =         NG_IPFW_NODE_TYPE,
   84         .mod_event =    ng_ipfw_mod_event,
   85         .constructor =  ng_ipfw_constructor,
   86         .shutdown =     ng_ipfw_shutdown,
   87         .newhook =      ng_ipfw_newhook,
   88         .connect =      ng_ipfw_connect,
   89         .findhook =     ng_ipfw_findhook,
   90         .rcvdata =      ng_ipfw_rcvdata,
   91         .disconnect =   ng_ipfw_disconnect,
   92 };
   93 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
   94 MODULE_DEPEND(ng_ipfw, ipfw, 3, 3, 3);
   95 
   96 /* Information we store for each hook */
   97 struct ng_ipfw_hook_priv {
   98         hook_p          hook;
   99         u_int16_t       rulenum;
  100 };
  101 typedef struct ng_ipfw_hook_priv *hpriv_p;
  102 
  103 static int
  104 ng_ipfw_mod_event(module_t mod, int event, void *data)
  105 {
  106         int error = 0;
  107 
  108         switch (event) {
  109         case MOD_LOAD:
  110 
  111                 if (ng_ipfw_input_p != NULL) {
  112                         error = EEXIST;
  113                         break;
  114                 }
  115 
  116                 /* Setup node without any private data */
  117                 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
  118                     != 0) {
  119                         log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
  120                         break;
  121                 }
  122 
  123                 /* Try to name node */
  124                 if (ng_name_node(fw_node, "ipfw") != 0)
  125                         log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
  126                             __func__);
  127 
  128                 /* Register hook */
  129                 ng_ipfw_input_p = ng_ipfw_input;
  130                 break;
  131 
  132         case MOD_UNLOAD:
  133                  /*
  134                   * This won't happen if a node exists.
  135                   * ng_ipfw_input_p is already cleared.
  136                   */
  137                 break;
  138 
  139         default:
  140                 error = EOPNOTSUPP;
  141                 break;
  142         }
  143 
  144         return (error);
  145 }
  146 
  147 static int
  148 ng_ipfw_constructor(node_p node)
  149 {
  150         return (EINVAL);        /* Only one node */
  151 }
  152 
  153 static int
  154 ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
  155 {
  156         hpriv_p hpriv;
  157         u_int16_t rulenum;
  158         const char *cp;
  159         char *endptr;
  160 
  161         /* Protect from leading zero */
  162         if (name[0] == '' && name[1] != '\0')
  163                 return (EINVAL);
  164 
  165         /* Check that name contains only digits */
  166         for (cp = name; *cp != '\0'; cp++)
  167                 if (!isdigit(*cp))
  168                         return (EINVAL);
  169 
  170         /* Convert it to integer */
  171         rulenum = (u_int16_t)strtol(name, &endptr, 10);
  172         if (*endptr != '\0')
  173                 return (EINVAL);
  174 
  175         /* Allocate memory for this hook's private data */
  176         hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
  177         if (hpriv== NULL)
  178                 return (ENOMEM);
  179 
  180         hpriv->hook = hook;
  181         hpriv->rulenum = rulenum;
  182 
  183         NG_HOOK_SET_PRIVATE(hook, hpriv);
  184 
  185         return(0);
  186 }
  187 
  188 /*
  189  * Set hooks into queueing mode, to avoid recursion between
  190  * netgraph layer and ip_{input,output}.
  191  */
  192 static int
  193 ng_ipfw_connect(hook_p hook)
  194 {
  195         NG_HOOK_FORCE_QUEUE(hook);
  196         return (0);
  197 }
  198 
  199 /* Look up hook by name */
  200 static hook_p
  201 ng_ipfw_findhook(node_p node, const char *name)
  202 {
  203         u_int16_t n;    /* numeric representation of hook */
  204         char *endptr;
  205 
  206         n = (u_int16_t)strtol(name, &endptr, 10);
  207         if (*endptr != '\0')
  208                 return NULL;
  209         return ng_ipfw_findhook1(node, n);
  210 }
  211 
  212 /* Look up hook by rule number */
  213 static hook_p
  214 ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
  215 {
  216         hook_p  hook;
  217         hpriv_p hpriv;
  218 
  219         LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
  220                 hpriv = NG_HOOK_PRIVATE(hook);
  221                 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
  222                         return (hook);
  223         }
  224 
  225         return (NULL);
  226 }
  227 
  228 static int
  229 ng_ipfw_rcvdata(hook_p hook, item_p item)
  230 {
  231         struct m_tag *tag;
  232         struct ipfw_rule_ref *r;
  233         struct mbuf *m;
  234         struct ip *ip;
  235 
  236         NGI_GET_M(item, m);
  237         NG_FREE_ITEM(item);
  238 
  239         tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
  240         if (tag == NULL) {
  241                 NG_FREE_M(m);
  242                 return (EINVAL);        /* XXX: find smth better */
  243         }
  244 
  245         if (m->m_len < sizeof(struct ip) &&
  246             (m = m_pullup(m, sizeof(struct ip))) == NULL)
  247                 return (ENOBUFS);
  248 
  249         ip = mtod(m, struct ip *);
  250 
  251         r = (struct ipfw_rule_ref *)(tag + 1);
  252         if (r->info & IPFW_INFO_IN) {
  253                 switch (ip->ip_v) {
  254 #ifdef INET
  255                 case IPVERSION:
  256                         ip_input(m);
  257                         return (0);
  258 #endif
  259 #ifdef INET6
  260                 case IPV6_VERSION >> 4:
  261                         ip6_input(m);
  262                         return (0);
  263 #endif
  264                 }
  265         } else {
  266                 switch (ip->ip_v) {
  267 #ifdef INET
  268                 case IPVERSION:
  269                         return (ip_output(m, NULL, NULL, IP_FORWARDING,
  270                             NULL, NULL));
  271 #endif
  272 #ifdef INET6
  273                 case IPV6_VERSION >> 4:
  274                         return (ip6_output(m, NULL, NULL, 0, NULL,
  275                             NULL, NULL));
  276 #endif
  277                 }
  278         }
  279 
  280         /* unknown IP protocol version */
  281         NG_FREE_M(m);
  282         return (EPROTONOSUPPORT);
  283 }
  284 
  285 static int
  286 ng_ipfw_input(struct mbuf **m0, struct ip_fw_args *fwa, bool tee)
  287 {
  288         struct mbuf *m;
  289         hook_p  hook;
  290         int error = 0;
  291 
  292         /*
  293          * Node must be loaded and corresponding hook must be present.
  294          */
  295         if (fw_node == NULL || 
  296            (hook = ng_ipfw_findhook1(fw_node, fwa->rule.info)) == NULL)
  297                 return (ESRCH);         /* no hook associated with this rule */
  298 
  299         /*
  300          * We have two modes: in normal mode we add a tag to packet, which is
  301          * important to return packet back to IP stack. In tee mode we make
  302          * a copy of a packet and forward it into netgraph without a tag.
  303          */
  304         if (tee == false) {
  305                 struct m_tag *tag;
  306                 struct ipfw_rule_ref *r;
  307                 m = *m0;
  308                 *m0 = NULL;     /* it belongs now to netgraph */
  309 
  310                 tag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(*r),
  311                         M_NOWAIT|M_ZERO);
  312                 if (tag == NULL) {
  313                         m_freem(m);
  314                         return (ENOMEM);
  315                 }
  316                 r = (struct ipfw_rule_ref *)(tag + 1);
  317                 *r = fwa->rule;
  318                 r->info &= IPFW_ONEPASS;  /* keep this info */
  319                 r->info |= (fwa->flags & IPFW_ARGS_IN) ?
  320                     IPFW_INFO_IN : IPFW_INFO_OUT;
  321                 m_tag_prepend(m, tag);
  322 
  323         } else
  324                 if ((m = m_dup(*m0, M_NOWAIT)) == NULL)
  325                         return (ENOMEM);        /* which is ignored */
  326 
  327         if (m->m_len < sizeof(struct ip) &&
  328             (m = m_pullup(m, sizeof(struct ip))) == NULL)
  329                 return (EINVAL);
  330 
  331         NG_SEND_DATA_ONLY(error, hook, m);
  332 
  333         return (error);
  334 }
  335 
  336 static int
  337 ng_ipfw_shutdown(node_p node)
  338 {
  339 
  340         /*
  341          * After our single node has been removed,
  342          * the only thing that can be done is
  343          * 'kldunload ng_ipfw.ko'
  344          */
  345         ng_ipfw_input_p = NULL;
  346         NG_NODE_UNREF(node);
  347         return (0);
  348 }
  349 
  350 static int
  351 ng_ipfw_disconnect(hook_p hook)
  352 {
  353         const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
  354 
  355         free(hpriv, M_NETGRAPH);
  356         NG_HOOK_SET_PRIVATE(hook, NULL);
  357 
  358         return (0);
  359 }
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FreeBSD/Linux Kernel Cross Reference sys/netgraph/ng_ipfw.c

FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_ipfw.c
