ng_ipfw.c

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    1 /*-
    2  * Copyright 2005, Gleb Smirnoff <glebius@FreeBSD.org>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  *
   26  * $FreeBSD: releng/8.4/sys/netgraph/ng_ipfw.c 234645 2012-04-24 10:20:24Z melifaro $
   27  */
   28 
   29 #include "opt_inet.h"
   30 #include "opt_inet6.h"
   31 
   32 #include <sys/param.h>
   33 #include <sys/systm.h>
   34 #include <sys/kernel.h>
   35 #include <sys/lock.h>
   36 #include <sys/mbuf.h>
   37 #include <sys/malloc.h>
   38 #include <sys/ctype.h>
   39 #include <sys/errno.h>
   40 #include <sys/rwlock.h>
   41 #include <sys/socket.h>
   42 #include <sys/syslog.h>
   43 
   44 #include <net/if.h>
   45 
   46 #include <netinet/in.h>
   47 #include <netinet/in_systm.h>
   48 #include <netinet/in_var.h>
   49 #include <netinet/ip_var.h>
   50 #include <netinet/ip_fw.h>
   51 #include <netinet/ipfw/ip_fw_private.h>
   52 #include <netinet/ip.h>
   53 #include <netinet/ip6.h>
   54 #include <netinet6/ip6_var.h>
   55 
   56 #include <netgraph/ng_message.h>
   57 #include <netgraph/ng_parse.h>
   58 #include <netgraph/ng_ipfw.h>
   59 #include <netgraph/netgraph.h>
   60 
   61 static int              ng_ipfw_mod_event(module_t mod, int event, void *data);
   62 static ng_constructor_t ng_ipfw_constructor;
   63 static ng_shutdown_t    ng_ipfw_shutdown;
   64 static ng_newhook_t     ng_ipfw_newhook;
   65 static ng_connect_t     ng_ipfw_connect;
   66 static ng_findhook_t    ng_ipfw_findhook;
   67 static ng_rcvdata_t     ng_ipfw_rcvdata;
   68 static ng_disconnect_t  ng_ipfw_disconnect;
   69 
   70 static hook_p           ng_ipfw_findhook1(node_p, u_int16_t );
   71 static int              ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
   72                             int);
   73 
   74 /* We have only one node */
   75 static node_p   fw_node;
   76 
   77 /* Netgraph node type descriptor */
   78 static struct ng_type ng_ipfw_typestruct = {
   79         .version =      NG_ABI_VERSION,
   80         .name =         NG_IPFW_NODE_TYPE,
   81         .mod_event =    ng_ipfw_mod_event,
   82         .constructor =  ng_ipfw_constructor,
   83         .shutdown =     ng_ipfw_shutdown,
   84         .newhook =      ng_ipfw_newhook,
   85         .connect =      ng_ipfw_connect,
   86         .findhook =     ng_ipfw_findhook,
   87         .rcvdata =      ng_ipfw_rcvdata,
   88         .disconnect =   ng_ipfw_disconnect,
   89 };
   90 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
   91 MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2);
   92 
   93 /* Information we store for each hook */
   94 struct ng_ipfw_hook_priv {
   95         hook_p          hook;
   96         u_int16_t       rulenum;
   97 };
   98 typedef struct ng_ipfw_hook_priv *hpriv_p;
   99 
  100 static int
  101 ng_ipfw_mod_event(module_t mod, int event, void *data)
  102 {
  103         int error = 0;
  104 
  105         switch (event) {
  106         case MOD_LOAD:
  107 
  108                 if (ng_ipfw_input_p != NULL) {
  109                         error = EEXIST;
  110                         break;
  111                 }
  112 
  113                 /* Setup node without any private data */
  114                 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
  115                     != 0) {
  116                         log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
  117                         break;
  118                 };
  119 
  120                 /* Try to name node */
  121                 if (ng_name_node(fw_node, "ipfw") != 0)
  122                         log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
  123                             __func__);
  124 
  125                 /* Register hook */
  126                 ng_ipfw_input_p = ng_ipfw_input;
  127                 break;
  128 
  129         case MOD_UNLOAD:
  130                  /*
  131                   * This won't happen if a node exists.
  132                   * ng_ipfw_input_p is already cleared.
  133                   */
  134                 break;
  135 
  136         default:
  137                 error = EOPNOTSUPP;
  138                 break;
  139         }
  140 
  141         return (error);
  142 }
  143 
  144 static int
  145 ng_ipfw_constructor(node_p node)
  146 {
  147         return (EINVAL);        /* Only one node */
  148 }
  149 
  150 static int
  151 ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
  152 {
  153         hpriv_p hpriv;
  154         u_int16_t rulenum;
  155         const char *cp;
  156         char *endptr;
  157 
  158         /* Protect from leading zero */
  159         if (name[0] == '' && name[1] != '\0')
  160                 return (EINVAL);
  161 
  162         /* Check that name contains only digits */
  163         for (cp = name; *cp != '\0'; cp++)
  164                 if (!isdigit(*cp))
  165                         return (EINVAL);
  166 
  167         /* Convert it to integer */
  168         rulenum = (u_int16_t)strtol(name, &endptr, 10);
  169         if (*endptr != '\0')
  170                 return (EINVAL);
  171 
  172         /* Allocate memory for this hook's private data */
  173         hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
  174         if (hpriv== NULL)
  175                 return (ENOMEM);
  176 
  177         hpriv->hook = hook;
  178         hpriv->rulenum = rulenum;
  179 
  180         NG_HOOK_SET_PRIVATE(hook, hpriv);
  181 
  182         return(0);
  183 }
  184 
  185 /*
  186  * Set hooks into queueing mode, to avoid recursion between
  187  * netgraph layer and ip_{input,output}.
  188  */
  189 static int
  190 ng_ipfw_connect(hook_p hook)
  191 {
  192         NG_HOOK_FORCE_QUEUE(hook);
  193         return (0);
  194 }
  195 
  196 /* Look up hook by name */
  197 hook_p
  198 ng_ipfw_findhook(node_p node, const char *name)
  199 {
  200         u_int16_t n;    /* numeric representation of hook */
  201         char *endptr;
  202 
  203         n = (u_int16_t)strtol(name, &endptr, 10);
  204         if (*endptr != '\0')
  205                 return NULL;
  206         return ng_ipfw_findhook1(node, n);
  207 }
  208 
  209 /* Look up hook by rule number */
  210 static hook_p
  211 ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
  212 {
  213         hook_p  hook;
  214         hpriv_p hpriv;
  215 
  216         LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
  217                 hpriv = NG_HOOK_PRIVATE(hook);
  218                 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
  219                         return (hook);
  220         }
  221 
  222         return (NULL);
  223 }
  224 
  225 
  226 static int
  227 ng_ipfw_rcvdata(hook_p hook, item_p item)
  228 {
  229         struct m_tag *tag;
  230         struct ipfw_rule_ref *r;
  231         struct mbuf *m;
  232         struct ip *ip;
  233 
  234         NGI_GET_M(item, m);
  235         NG_FREE_ITEM(item);
  236 
  237         tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
  238         if (tag == NULL) {
  239                 NG_FREE_M(m);
  240                 return (EINVAL);        /* XXX: find smth better */
  241         };
  242 
  243         if (m->m_len < sizeof(struct ip) &&
  244             (m = m_pullup(m, sizeof(struct ip))) == NULL)
  245                 return (ENOBUFS);
  246 
  247         ip = mtod(m, struct ip *);
  248 
  249         r = (struct ipfw_rule_ref *)(tag + 1);
  250         if (r->info & IPFW_INFO_IN) {
  251                 switch (ip->ip_v) {
  252 #ifdef INET
  253                 case IPVERSION:
  254                         ip_input(m);
  255                         return (0);
  256 #endif
  257 #ifdef INET6
  258                 case IPV6_VERSION >> 4:
  259                         ip6_input(m);
  260                         return (0);
  261 #endif
  262                 }
  263         } else {
  264                 switch (ip->ip_v) {
  265 #ifdef INET
  266                 case IPVERSION:
  267                         SET_HOST_IPLEN(ip);
  268                         return (ip_output(m, NULL, NULL, IP_FORWARDING,
  269                             NULL, NULL));
  270 #endif
  271 #ifdef INET6
  272                 case IPV6_VERSION >> 4:
  273                         return (ip6_output(m, NULL, NULL, 0, NULL,
  274                             NULL, NULL));
  275 #endif
  276                 }
  277         }
  278 
  279         /* unknown IP protocol version */
  280         NG_FREE_M(m);
  281         return (EPROTONOSUPPORT);
  282 }
  283 
  284 static int
  285 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee)
  286 {
  287         struct mbuf *m;
  288         struct ip *ip;
  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 == 0) {
  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 |= dir ? IPFW_INFO_IN : IPFW_INFO_OUT;
  320                 m_tag_prepend(m, tag);
  321 
  322         } else
  323                 if ((m = m_dup(*m0, M_DONTWAIT)) == NULL)
  324                         return (ENOMEM);        /* which is ignored */
  325 
  326         if (m->m_len < sizeof(struct ip) &&
  327             (m = m_pullup(m, sizeof(struct ip))) == NULL)
  328                 return (EINVAL);
  329 
  330         ip = mtod(m, struct ip *);
  331 
  332         NG_SEND_DATA_ONLY(error, hook, m);
  333 
  334         return (error);
  335 }
  336 
  337 static int
  338 ng_ipfw_shutdown(node_p node)
  339 {
  340 
  341         /*
  342          * After our single node has been removed,
  343          * the only thing that can be done is
  344          * 'kldunload ng_ipfw.ko'
  345          */
  346         ng_ipfw_input_p = NULL;
  347         NG_NODE_UNREF(node);
  348         return (0);
  349 }
  350 
  351 static int
  352 ng_ipfw_disconnect(hook_p hook)
  353 {
  354         const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
  355 
  356         free(hpriv, M_NETGRAPH);
  357         NG_HOOK_SET_PRIVATE(hook, NULL);
  358 
  359         return (0);
  360 }
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FreeBSD/Linux Kernel Cross Reference sys/netgraph/ng_ipfw.c

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sys/netgraph/ng_ipfw.c
