sys/netgraph7/ng_ipfw.c

   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: src/sys/netgraph/ng_ipfw.c,v 1.9 2006/02/14 15:22:24 ru Exp $
  27  * $DragonFly: src/sys/netgraph7/ng_ipfw.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/kernel.h>
  33 #include <sys/mbuf.h>
  34 #include <sys/malloc.h>
  35 #include <sys/ctype.h>
  36 #include <sys/errno.h>
  37 #include <sys/socket.h>
  38 #include <sys/syslog.h>
  39
  40 #include <net/if.h>
  41
  42 #include <netinet/in.h>
  43 #include <netinet/in_systm.h>
  44 #include <netinet/in_var.h>
  45 #include <netinet/ip_fw.h>
  46 #include <netinet/ip.h>
  47 #include <netinet/ip_var.h>
  48
  49 #include "ng_message.h"
  50 #include "ng_parse.h"
  51 #include "ng_ipfw.h"
  52 #include "netgraph.h"
  53
  54 static int              ng_ipfw_mod_event(module_t mod, int event, void *data);
  55 static ng_constructor_t ng_ipfw_constructor;
  56 static ng_shutdown_t    ng_ipfw_shutdown;
  57 static ng_newhook_t     ng_ipfw_newhook;
  58 static ng_connect_t     ng_ipfw_connect;
  59 static ng_findhook_t    ng_ipfw_findhook;
  60 static ng_rcvdata_t     ng_ipfw_rcvdata;
  61 static ng_disconnect_t  ng_ipfw_disconnect;
  62
  63 static hook_p           ng_ipfw_findhook1(node_p, u_int16_t );
  64 static int              ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
  65                             int);
  66
  67 /* We have only one node */
  68 static node_p   fw_node;
  69
  70 /* Netgraph node type descriptor */
  71 static struct ng_type ng_ipfw_typestruct = {
  72         .version =      NG_ABI_VERSION,
  73         .name =         NG_IPFW_NODE_TYPE,
  74         .mod_event =    ng_ipfw_mod_event,
  75         .constructor =  ng_ipfw_constructor,
  76         .shutdown =     ng_ipfw_shutdown,
  77         .newhook =      ng_ipfw_newhook,
  78         .connect =      ng_ipfw_connect,
  79         .findhook =     ng_ipfw_findhook,
  80         .rcvdata =      ng_ipfw_rcvdata,
  81         .disconnect =   ng_ipfw_disconnect,
  82 };
  83 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
  84 MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2);
  85
  86 /* Information we store for each hook */
  87 struct ng_ipfw_hook_priv {
  88         hook_p          hook;
  89         u_int16_t       rulenum;
  90 };
  91 typedef struct ng_ipfw_hook_priv *hpriv_p;
  92
  93 static int
  94 ng_ipfw_mod_event(module_t mod, int event, void *data)
  95 {
  96         int error = 0;
  97
  98         switch (event) {
  99         case MOD_LOAD:
 100
 101                 if (ng_ipfw_input_p != NULL) {
 102                         error = EEXIST;
 103                         break;
 104                 }
 105
 106                 /* Setup node without any private data */
 107                 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
 108                     != 0) {
 109                         log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
 110                         break;
 111                 };
 112
 113                 /* Try to name node */
 114                 if (ng_name_node(fw_node, "ipfw") != 0)
 115                         log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
 116                             __func__);
 117
 118                 /* Register hook */
 119                 ng_ipfw_input_p = ng_ipfw_input;
 120                 break;
 121
 122         case MOD_UNLOAD:
 123                  /*
 124                   * This won't happen if a node exists.
 125                   * ng_ipfw_input_p is already cleared.
 126                   */
 127                 break;
 128
 129         default:
 130                 error = EOPNOTSUPP;
 131                 break;
 132         }
 133
 134         return (error);
 135 }
 136
 137 static int
 138 ng_ipfw_constructor(node_p node)
 139 {
 140         return (EINVAL);        /* Only one node */
 141 }
 142
 143 static int
 144 ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
 145 {
 146         hpriv_p hpriv;
 147         u_int16_t rulenum;
 148         const char *cp;
 149         char *endptr;
 150
 151         /* Protect from leading zero */
 152         if (name[0] == '0' && name[1] != '\0')
 153                 return (EINVAL);
 154
 155         /* Check that name contains only digits */
 156         for (cp = name; *cp != '\0'; cp++)
 157                 if (!isdigit(*cp))
 158                         return (EINVAL);
 159
 160         /* Convert it to integer */
 161         rulenum = (u_int16_t)strtol(name, &endptr, 10);
 162         if (*endptr != '\0')
 163                 return (EINVAL);
 164
 165         /* Allocate memory for this hook's private data */
 166         hpriv = kmalloc(sizeof(*hpriv), M_NETGRAPH,
 167                         M_WAITOK | M_NULLOK | M_ZERO);
 168         if (hpriv== NULL)
 169                 return (ENOMEM);
 170
 171         hpriv->hook = hook;
 172         hpriv->rulenum = rulenum;
 173
 174         NG_HOOK_SET_PRIVATE(hook, hpriv);
 175
 176         return(0);
 177 }
 178
 179 /*
 180  * Set hooks into queueing mode, to avoid recursion between
 181  * netgraph layer and ip_{input,output}.
 182  */
 183 static int
 184 ng_ipfw_connect(hook_p hook)
 185 {
 186         NG_HOOK_FORCE_QUEUE(hook);
 187         return (0);
 188 }
 189
 190 /* Look up hook by name */
 191 hook_p
 192 ng_ipfw_findhook(node_p node, const char *name)
 193 {
 194         u_int16_t n;    /* numeric representation of hook */
 195         char *endptr;
 196
 197         n = (u_int16_t)strtol(name, &endptr, 10);
 198         if (*endptr != '\0')
 199                 return NULL;
 200         return ng_ipfw_findhook1(node, n);
 201 }
 202
 203 /* Look up hook by rule number */
 204 static hook_p
 205 ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
 206 {
 207         hook_p  hook;
 208         hpriv_p hpriv;
 209
 210         LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
 211                 hpriv = NG_HOOK_PRIVATE(hook);
 212                 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
 213                         return (hook);
 214         }
 215
 216         return (NULL);
 217 }
 218
 219
 220 static int
 221 ng_ipfw_rcvdata(hook_p hook, item_p item)
 222 {
 223         struct ng_ipfw_tag      *ngit;
 224         struct mbuf *m;
 225
 226         NGI_GET_M(item, m);
 227         NG_FREE_ITEM(item);
 228
 229         if ((ngit = (struct ng_ipfw_tag *)m_tag_locate(m, NGM_IPFW_COOKIE, 0,
 230             NULL)) == NULL) {
 231                 NG_FREE_M(m);
 232                 return (EINVAL);        /* XXX: find smth better */
 233         };
 234
 235         switch (ngit->dir) {
 236         case NG_IPFW_OUT:
 237             {
 238                 struct ip *ip;
 239
 240                 if (m->m_len < sizeof(struct ip) &&
 241                     (m = m_pullup(m, sizeof(struct ip))) == NULL)
 242                         return (EINVAL);
 243
 244                 ip = mtod(m, struct ip *);
 245
 246                 ip->ip_len = ntohs(ip->ip_len);
 247                 ip->ip_off = ntohs(ip->ip_off);
 248
 249                 return ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
 250             }
 251         case NG_IPFW_IN:
 252                 ip_input(m);
 253                 return (0);
 254         default:
 255                 panic("ng_ipfw_rcvdata: bad dir %u", ngit->dir);
 256         }
 257
 258         /* not reached */
 259         return (0);
 260 }
 261
 262 static int
 263 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee)
 264 {
 265         struct mbuf *m;
 266         struct ng_ipfw_tag *ngit;
 267         struct ip *ip;
 268         hook_p  hook;
 269         int error = 0;
 270
 271         /*
 272          * Node must be loaded and corresponding hook must be present.
 273          */
 274         if (fw_node == NULL ||
 275            (hook = ng_ipfw_findhook1(fw_node, fwa->cookie)) == NULL) {
 276                 if (tee == 0)
 277                         m_freem(*m0);
 278                 return (ESRCH);         /* no hook associated with this rule */
 279         }
 280
 281         /*
 282          * We have two modes: in normal mode we add a tag to packet, which is
 283          * important to return packet back to IP stack. In tee mode we make
 284          * a copy of a packet and forward it into netgraph without a tag.
 285          */
 286         if (tee == 0) {
 287                 m = *m0;
 288                 *m0 = NULL;     /* it belongs now to netgraph */
 289
 290                 if ((ngit = (struct ng_ipfw_tag *)m_tag_alloc(NGM_IPFW_COOKIE,
 291                     0, TAGSIZ, MB_DONTWAIT)) == NULL) {
 292                         m_freem(m);
 293                         return (ENOMEM);
 294                 }
 295                 ngit->rule = fwa->rule;
 296                 ngit->dir = dir;
 297                 ngit->ifp = fwa->oif;
 298                 m_tag_prepend(m, &ngit->mt);
 299
 300         } else
 301                 if ((m = m_dup(*m0, MB_DONTWAIT)) == NULL)
 302                         return (ENOMEM);        /* which is ignored */
 303
 304         if (m->m_len < sizeof(struct ip) &&
 305             (m = m_pullup(m, sizeof(struct ip))) == NULL)
 306                 return (EINVAL);
 307
 308         ip = mtod(m, struct ip *);
 309         ip->ip_len = htons(ip->ip_len);
 310         ip->ip_off = htons(ip->ip_off);
 311
 312         NG_SEND_DATA_ONLY(error, hook, m);
 313
 314         return (error);
 315 }
 316
 317 static int
 318 ng_ipfw_shutdown(node_p node)
 319 {
 320
 321         /*
 322          * After our single node has been removed,
 323          * the only thing that can be done is
 324          * 'kldunload ng_ipfw.ko'
 325          */
 326         ng_ipfw_input_p = NULL;
 327         NG_NODE_UNREF(node);
 328         return (0);
 329 }
 330
 331 static int
 332 ng_ipfw_disconnect(hook_p hook)
 333 {
 334         const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
 335
 336         kfree(hpriv, M_NETGRAPH);
 337         NG_HOOK_SET_PRIVATE(hook, NULL);
 338
 339         return (0);
 340 }