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/10.4/sys/netgraph/ng_ipfw.c 243882 2012-12-05 08:04:20Z glebius $
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/ip.h>
52 #include <netinet/ip6.h>
53 #include <netinet6/ip6_var.h>
54
55 #include <netpfil/ipfw/ip_fw_private.h>
56
57 #include <netgraph/ng_message.h>
58 #include <netgraph/ng_parse.h>
59 #include <netgraph/ng_ipfw.h>
60 #include <netgraph/netgraph.h>
61
62 static int ng_ipfw_mod_event(module_t mod, int event, void *data);
63 static ng_constructor_t ng_ipfw_constructor;
64 static ng_shutdown_t ng_ipfw_shutdown;
65 static ng_newhook_t ng_ipfw_newhook;
66 static ng_connect_t ng_ipfw_connect;
67 static ng_findhook_t ng_ipfw_findhook;
68 static ng_rcvdata_t ng_ipfw_rcvdata;
69 static ng_disconnect_t ng_ipfw_disconnect;
70
71 static hook_p ng_ipfw_findhook1(node_p, u_int16_t );
72 static int ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
73 int);
74
75 /* We have only one node */
76 static node_p fw_node;
77
78 /* Netgraph node type descriptor */
79 static struct ng_type ng_ipfw_typestruct = {
80 .version = NG_ABI_VERSION,
81 .name = NG_IPFW_NODE_TYPE,
82 .mod_event = ng_ipfw_mod_event,
83 .constructor = ng_ipfw_constructor,
84 .shutdown = ng_ipfw_shutdown,
85 .newhook = ng_ipfw_newhook,
86 .connect = ng_ipfw_connect,
87 .findhook = ng_ipfw_findhook,
88 .rcvdata = ng_ipfw_rcvdata,
89 .disconnect = ng_ipfw_disconnect,
90 };
91 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
92 MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2);
93
94 /* Information we store for each hook */
95 struct ng_ipfw_hook_priv {
96 hook_p hook;
97 u_int16_t rulenum;
98 };
99 typedef struct ng_ipfw_hook_priv *hpriv_p;
100
101 static int
102 ng_ipfw_mod_event(module_t mod, int event, void *data)
103 {
104 int error = 0;
105
106 switch (event) {
107 case MOD_LOAD:
108
109 if (ng_ipfw_input_p != NULL) {
110 error = EEXIST;
111 break;
112 }
113
114 /* Setup node without any private data */
115 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
116 != 0) {
117 log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
118 break;
119 };
120
121 /* Try to name node */
122 if (ng_name_node(fw_node, "ipfw") != 0)
123 log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
124 __func__);
125
126 /* Register hook */
127 ng_ipfw_input_p = ng_ipfw_input;
128 break;
129
130 case MOD_UNLOAD:
131 /*
132 * This won't happen if a node exists.
133 * ng_ipfw_input_p is already cleared.
134 */
135 break;
136
137 default:
138 error = EOPNOTSUPP;
139 break;
140 }
141
142 return (error);
143 }
144
145 static int
146 ng_ipfw_constructor(node_p node)
147 {
148 return (EINVAL); /* Only one node */
149 }
150
151 static int
152 ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
153 {
154 hpriv_p hpriv;
155 u_int16_t rulenum;
156 const char *cp;
157 char *endptr;
158
159 /* Protect from leading zero */
160 if (name[0] == '' && name[1] != '\0')
161 return (EINVAL);
162
163 /* Check that name contains only digits */
164 for (cp = name; *cp != '\0'; cp++)
165 if (!isdigit(*cp))
166 return (EINVAL);
167
168 /* Convert it to integer */
169 rulenum = (u_int16_t)strtol(name, &endptr, 10);
170 if (*endptr != '\0')
171 return (EINVAL);
172
173 /* Allocate memory for this hook's private data */
174 hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
175 if (hpriv== NULL)
176 return (ENOMEM);
177
178 hpriv->hook = hook;
179 hpriv->rulenum = rulenum;
180
181 NG_HOOK_SET_PRIVATE(hook, hpriv);
182
183 return(0);
184 }
185
186 /*
187 * Set hooks into queueing mode, to avoid recursion between
188 * netgraph layer and ip_{input,output}.
189 */
190 static int
191 ng_ipfw_connect(hook_p hook)
192 {
193 NG_HOOK_FORCE_QUEUE(hook);
194 return (0);
195 }
196
197 /* Look up hook by name */
198 static hook_p
199 ng_ipfw_findhook(node_p node, const char *name)
200 {
201 u_int16_t n; /* numeric representation of hook */
202 char *endptr;
203
204 n = (u_int16_t)strtol(name, &endptr, 10);
205 if (*endptr != '\0')
206 return NULL;
207 return ng_ipfw_findhook1(node, n);
208 }
209
210 /* Look up hook by rule number */
211 static hook_p
212 ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
213 {
214 hook_p hook;
215 hpriv_p hpriv;
216
217 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
218 hpriv = NG_HOOK_PRIVATE(hook);
219 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
220 return (hook);
221 }
222
223 return (NULL);
224 }
225
226
227 static int
228 ng_ipfw_rcvdata(hook_p hook, item_p item)
229 {
230 struct m_tag *tag;
231 struct ipfw_rule_ref *r;
232 struct mbuf *m;
233 struct ip *ip;
234
235 NGI_GET_M(item, m);
236 NG_FREE_ITEM(item);
237
238 tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
239 if (tag == NULL) {
240 NG_FREE_M(m);
241 return (EINVAL); /* XXX: find smth better */
242 };
243
244 if (m->m_len < sizeof(struct ip) &&
245 (m = m_pullup(m, sizeof(struct ip))) == NULL)
246 return (ENOBUFS);
247
248 ip = mtod(m, struct ip *);
249
250 r = (struct ipfw_rule_ref *)(tag + 1);
251 if (r->info & IPFW_INFO_IN) {
252 switch (ip->ip_v) {
253 #ifdef INET
254 case IPVERSION:
255 ip_input(m);
256 return (0);
257 #endif
258 #ifdef INET6
259 case IPV6_VERSION >> 4:
260 ip6_input(m);
261 return (0);
262 #endif
263 }
264 } else {
265 switch (ip->ip_v) {
266 #ifdef INET
267 case IPVERSION:
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_NOWAIT)) == 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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