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/8.1/sys/netgraph/ng_ipfw.c 205511 2010-03-23 09:58:59Z luigi $
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/lock.h>
33 #include <sys/mbuf.h>
34 #include <sys/malloc.h>
35 #include <sys/ctype.h>
36 #include <sys/errno.h>
37 #include <sys/rwlock.h>
38 #include <sys/socket.h>
39 #include <sys/syslog.h>
40
41 #include <net/if.h>
42
43 #include <netinet/in.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/in_var.h>
46 #include <netinet/ip_var.h>
47 #include <netinet/ip_fw.h>
48 #include <netinet/ipfw/ip_fw_private.h>
49 #include <netinet/ip.h>
50
51 #include <netgraph/ng_message.h>
52 #include <netgraph/ng_parse.h>
53 #include <netgraph/ng_ipfw.h>
54 #include <netgraph/netgraph.h>
55
56 static int ng_ipfw_mod_event(module_t mod, int event, void *data);
57 static ng_constructor_t ng_ipfw_constructor;
58 static ng_shutdown_t ng_ipfw_shutdown;
59 static ng_newhook_t ng_ipfw_newhook;
60 static ng_connect_t ng_ipfw_connect;
61 static ng_findhook_t ng_ipfw_findhook;
62 static ng_rcvdata_t ng_ipfw_rcvdata;
63 static ng_disconnect_t ng_ipfw_disconnect;
64
65 static hook_p ng_ipfw_findhook1(node_p, u_int16_t );
66 static int ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
67 int);
68
69 /* We have only one node */
70 static node_p fw_node;
71
72 /* Netgraph node type descriptor */
73 static struct ng_type ng_ipfw_typestruct = {
74 .version = NG_ABI_VERSION,
75 .name = NG_IPFW_NODE_TYPE,
76 .mod_event = ng_ipfw_mod_event,
77 .constructor = ng_ipfw_constructor,
78 .shutdown = ng_ipfw_shutdown,
79 .newhook = ng_ipfw_newhook,
80 .connect = ng_ipfw_connect,
81 .findhook = ng_ipfw_findhook,
82 .rcvdata = ng_ipfw_rcvdata,
83 .disconnect = ng_ipfw_disconnect,
84 };
85 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
86 MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2);
87
88 /* Information we store for each hook */
89 struct ng_ipfw_hook_priv {
90 hook_p hook;
91 u_int16_t rulenum;
92 };
93 typedef struct ng_ipfw_hook_priv *hpriv_p;
94
95 static int
96 ng_ipfw_mod_event(module_t mod, int event, void *data)
97 {
98 int error = 0;
99
100 switch (event) {
101 case MOD_LOAD:
102
103 if (ng_ipfw_input_p != NULL) {
104 error = EEXIST;
105 break;
106 }
107
108 /* Setup node without any private data */
109 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
110 != 0) {
111 log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
112 break;
113 };
114
115 /* Try to name node */
116 if (ng_name_node(fw_node, "ipfw") != 0)
117 log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
118 __func__);
119
120 /* Register hook */
121 ng_ipfw_input_p = ng_ipfw_input;
122 break;
123
124 case MOD_UNLOAD:
125 /*
126 * This won't happen if a node exists.
127 * ng_ipfw_input_p is already cleared.
128 */
129 break;
130
131 default:
132 error = EOPNOTSUPP;
133 break;
134 }
135
136 return (error);
137 }
138
139 static int
140 ng_ipfw_constructor(node_p node)
141 {
142 return (EINVAL); /* Only one node */
143 }
144
145 static int
146 ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
147 {
148 hpriv_p hpriv;
149 u_int16_t rulenum;
150 const char *cp;
151 char *endptr;
152
153 /* Protect from leading zero */
154 if (name[0] == '' && name[1] != '\0')
155 return (EINVAL);
156
157 /* Check that name contains only digits */
158 for (cp = name; *cp != '\0'; cp++)
159 if (!isdigit(*cp))
160 return (EINVAL);
161
162 /* Convert it to integer */
163 rulenum = (u_int16_t)strtol(name, &endptr, 10);
164 if (*endptr != '\0')
165 return (EINVAL);
166
167 /* Allocate memory for this hook's private data */
168 hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
169 if (hpriv== NULL)
170 return (ENOMEM);
171
172 hpriv->hook = hook;
173 hpriv->rulenum = rulenum;
174
175 NG_HOOK_SET_PRIVATE(hook, hpriv);
176
177 return(0);
178 }
179
180 /*
181 * Set hooks into queueing mode, to avoid recursion between
182 * netgraph layer and ip_{input,output}.
183 */
184 static int
185 ng_ipfw_connect(hook_p hook)
186 {
187 NG_HOOK_FORCE_QUEUE(hook);
188 return (0);
189 }
190
191 /* Look up hook by name */
192 hook_p
193 ng_ipfw_findhook(node_p node, const char *name)
194 {
195 u_int16_t n; /* numeric representation of hook */
196 char *endptr;
197
198 n = (u_int16_t)strtol(name, &endptr, 10);
199 if (*endptr != '\0')
200 return NULL;
201 return ng_ipfw_findhook1(node, n);
202 }
203
204 /* Look up hook by rule number */
205 static hook_p
206 ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
207 {
208 hook_p hook;
209 hpriv_p hpriv;
210
211 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
212 hpriv = NG_HOOK_PRIVATE(hook);
213 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
214 return (hook);
215 }
216
217 return (NULL);
218 }
219
220
221 static int
222 ng_ipfw_rcvdata(hook_p hook, item_p item)
223 {
224 struct ipfw_rule_ref *tag;
225 struct mbuf *m;
226
227 NGI_GET_M(item, m);
228 NG_FREE_ITEM(item);
229
230 tag = (struct ipfw_rule_ref *)
231 m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
232 if (tag == NULL) {
233 NG_FREE_M(m);
234 return (EINVAL); /* XXX: find smth better */
235 };
236
237 if (tag->info & IPFW_INFO_IN) {
238 ip_input(m);
239 return (0);
240 } else {
241 struct ip *ip;
242
243 if (m->m_len < sizeof(struct ip) &&
244 (m = m_pullup(m, sizeof(struct ip))) == NULL)
245 return (EINVAL);
246
247 ip = mtod(m, struct ip *);
248
249 SET_HOST_IPLEN(ip);
250
251 return ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
252 }
253 }
254
255 static int
256 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee)
257 {
258 struct mbuf *m;
259 struct ip *ip;
260 hook_p hook;
261 int error = 0;
262
263 /*
264 * Node must be loaded and corresponding hook must be present.
265 */
266 if (fw_node == NULL ||
267 (hook = ng_ipfw_findhook1(fw_node, fwa->rule.info)) == NULL) {
268 if (tee == 0)
269 m_freem(*m0);
270 return (ESRCH); /* no hook associated with this rule */
271 }
272
273 /*
274 * We have two modes: in normal mode we add a tag to packet, which is
275 * important to return packet back to IP stack. In tee mode we make
276 * a copy of a packet and forward it into netgraph without a tag.
277 */
278 if (tee == 0) {
279 struct m_tag *tag;
280 struct ipfw_rule_ref *r;
281 m = *m0;
282 *m0 = NULL; /* it belongs now to netgraph */
283
284 tag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(*r),
285 M_NOWAIT|M_ZERO);
286 if (tag == NULL) {
287 m_freem(m);
288 return (ENOMEM);
289 }
290 r = (struct ipfw_rule_ref *)(tag + 1);
291 *r = fwa->rule;
292 r->info = dir ? IPFW_INFO_IN : IPFW_INFO_OUT;
293 m_tag_prepend(m, tag);
294
295 } else
296 if ((m = m_dup(*m0, M_DONTWAIT)) == NULL)
297 return (ENOMEM); /* which is ignored */
298
299 if (m->m_len < sizeof(struct ip) &&
300 (m = m_pullup(m, sizeof(struct ip))) == NULL)
301 return (EINVAL);
302
303 ip = mtod(m, struct ip *);
304
305 NG_SEND_DATA_ONLY(error, hook, m);
306
307 return (error);
308 }
309
310 static int
311 ng_ipfw_shutdown(node_p node)
312 {
313
314 /*
315 * After our single node has been removed,
316 * the only thing that can be done is
317 * 'kldunload ng_ipfw.ko'
318 */
319 ng_ipfw_input_p = NULL;
320 NG_NODE_UNREF(node);
321 return (0);
322 }
323
324 static int
325 ng_ipfw_disconnect(hook_p hook)
326 {
327 const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
328
329 free(hpriv, M_NETGRAPH);
330 NG_HOOK_SET_PRIVATE(hook, NULL);
331
332 return (0);
333 }
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