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