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/11.0/sys/netgraph/ng_ipfw.c 297793 2016-04-10 23:07:00Z pfg $
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 #include <net/if_var.h>
46
47 #include <netinet/in.h>
48 #include <netinet/in_systm.h>
49 #include <netinet/in_var.h>
50 #include <netinet/ip_var.h>
51 #include <netinet/ip_fw.h>
52 #include <netinet/ip.h>
53 #include <netinet/ip6.h>
54 #include <netinet6/ip6_var.h>
55
56 #include <netpfil/ipfw/ip_fw_private.h>
57
58 #include <netgraph/ng_message.h>
59 #include <netgraph/ng_parse.h>
60 #include <netgraph/ng_ipfw.h>
61 #include <netgraph/netgraph.h>
62
63 static int ng_ipfw_mod_event(module_t mod, int event, void *data);
64 static ng_constructor_t ng_ipfw_constructor;
65 static ng_shutdown_t ng_ipfw_shutdown;
66 static ng_newhook_t ng_ipfw_newhook;
67 static ng_connect_t ng_ipfw_connect;
68 static ng_findhook_t ng_ipfw_findhook;
69 static ng_rcvdata_t ng_ipfw_rcvdata;
70 static ng_disconnect_t ng_ipfw_disconnect;
71
72 static hook_p ng_ipfw_findhook1(node_p, u_int16_t );
73 static int ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
74 int);
75
76 /* We have only one node */
77 static node_p fw_node;
78
79 /* Netgraph node type descriptor */
80 static struct ng_type ng_ipfw_typestruct = {
81 .version = NG_ABI_VERSION,
82 .name = NG_IPFW_NODE_TYPE,
83 .mod_event = ng_ipfw_mod_event,
84 .constructor = ng_ipfw_constructor,
85 .shutdown = ng_ipfw_shutdown,
86 .newhook = ng_ipfw_newhook,
87 .connect = ng_ipfw_connect,
88 .findhook = ng_ipfw_findhook,
89 .rcvdata = ng_ipfw_rcvdata,
90 .disconnect = ng_ipfw_disconnect,
91 };
92 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
93 MODULE_DEPEND(ng_ipfw, ipfw, 3, 3, 3);
94
95 /* Information we store for each hook */
96 struct ng_ipfw_hook_priv {
97 hook_p hook;
98 u_int16_t rulenum;
99 };
100 typedef struct ng_ipfw_hook_priv *hpriv_p;
101
102 static int
103 ng_ipfw_mod_event(module_t mod, int event, void *data)
104 {
105 int error = 0;
106
107 switch (event) {
108 case MOD_LOAD:
109
110 if (ng_ipfw_input_p != NULL) {
111 error = EEXIST;
112 break;
113 }
114
115 /* Setup node without any private data */
116 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
117 != 0) {
118 log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
119 break;
120 }
121
122 /* Try to name node */
123 if (ng_name_node(fw_node, "ipfw") != 0)
124 log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
125 __func__);
126
127 /* Register hook */
128 ng_ipfw_input_p = ng_ipfw_input;
129 break;
130
131 case MOD_UNLOAD:
132 /*
133 * This won't happen if a node exists.
134 * ng_ipfw_input_p is already cleared.
135 */
136 break;
137
138 default:
139 error = EOPNOTSUPP;
140 break;
141 }
142
143 return (error);
144 }
145
146 static int
147 ng_ipfw_constructor(node_p node)
148 {
149 return (EINVAL); /* Only one node */
150 }
151
152 static int
153 ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
154 {
155 hpriv_p hpriv;
156 u_int16_t rulenum;
157 const char *cp;
158 char *endptr;
159
160 /* Protect from leading zero */
161 if (name[0] == '' && name[1] != '\0')
162 return (EINVAL);
163
164 /* Check that name contains only digits */
165 for (cp = name; *cp != '\0'; cp++)
166 if (!isdigit(*cp))
167 return (EINVAL);
168
169 /* Convert it to integer */
170 rulenum = (u_int16_t)strtol(name, &endptr, 10);
171 if (*endptr != '\0')
172 return (EINVAL);
173
174 /* Allocate memory for this hook's private data */
175 hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
176 if (hpriv== NULL)
177 return (ENOMEM);
178
179 hpriv->hook = hook;
180 hpriv->rulenum = rulenum;
181
182 NG_HOOK_SET_PRIVATE(hook, hpriv);
183
184 return(0);
185 }
186
187 /*
188 * Set hooks into queueing mode, to avoid recursion between
189 * netgraph layer and ip_{input,output}.
190 */
191 static int
192 ng_ipfw_connect(hook_p hook)
193 {
194 NG_HOOK_FORCE_QUEUE(hook);
195 return (0);
196 }
197
198 /* Look up hook by name */
199 static hook_p
200 ng_ipfw_findhook(node_p node, const char *name)
201 {
202 u_int16_t n; /* numeric representation of hook */
203 char *endptr;
204
205 n = (u_int16_t)strtol(name, &endptr, 10);
206 if (*endptr != '\0')
207 return NULL;
208 return ng_ipfw_findhook1(node, n);
209 }
210
211 /* Look up hook by rule number */
212 static hook_p
213 ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
214 {
215 hook_p hook;
216 hpriv_p hpriv;
217
218 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
219 hpriv = NG_HOOK_PRIVATE(hook);
220 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
221 return (hook);
222 }
223
224 return (NULL);
225 }
226
227
228 static int
229 ng_ipfw_rcvdata(hook_p hook, item_p item)
230 {
231 struct m_tag *tag;
232 struct ipfw_rule_ref *r;
233 struct mbuf *m;
234 struct ip *ip;
235
236 NGI_GET_M(item, m);
237 NG_FREE_ITEM(item);
238
239 tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
240 if (tag == NULL) {
241 NG_FREE_M(m);
242 return (EINVAL); /* XXX: find smth better */
243 }
244
245 if (m->m_len < sizeof(struct ip) &&
246 (m = m_pullup(m, sizeof(struct ip))) == NULL)
247 return (ENOBUFS);
248
249 ip = mtod(m, struct ip *);
250
251 r = (struct ipfw_rule_ref *)(tag + 1);
252 if (r->info & IPFW_INFO_IN) {
253 switch (ip->ip_v) {
254 #ifdef INET
255 case IPVERSION:
256 ip_input(m);
257 return (0);
258 #endif
259 #ifdef INET6
260 case IPV6_VERSION >> 4:
261 ip6_input(m);
262 return (0);
263 #endif
264 }
265 } else {
266 switch (ip->ip_v) {
267 #ifdef INET
268 case IPVERSION:
269 return (ip_output(m, NULL, NULL, IP_FORWARDING,
270 NULL, NULL));
271 #endif
272 #ifdef INET6
273 case IPV6_VERSION >> 4:
274 return (ip6_output(m, NULL, NULL, 0, NULL,
275 NULL, NULL));
276 #endif
277 }
278 }
279
280 /* unknown IP protocol version */
281 NG_FREE_M(m);
282 return (EPROTONOSUPPORT);
283 }
284
285 static int
286 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee)
287 {
288 struct mbuf *m;
289 struct ip *ip;
290 hook_p hook;
291 int error = 0;
292
293 /*
294 * Node must be loaded and corresponding hook must be present.
295 */
296 if (fw_node == NULL ||
297 (hook = ng_ipfw_findhook1(fw_node, fwa->rule.info)) == NULL)
298 return (ESRCH); /* no hook associated with this rule */
299
300 /*
301 * We have two modes: in normal mode we add a tag to packet, which is
302 * important to return packet back to IP stack. In tee mode we make
303 * a copy of a packet and forward it into netgraph without a tag.
304 */
305 if (tee == 0) {
306 struct m_tag *tag;
307 struct ipfw_rule_ref *r;
308 m = *m0;
309 *m0 = NULL; /* it belongs now to netgraph */
310
311 tag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(*r),
312 M_NOWAIT|M_ZERO);
313 if (tag == NULL) {
314 m_freem(m);
315 return (ENOMEM);
316 }
317 r = (struct ipfw_rule_ref *)(tag + 1);
318 *r = fwa->rule;
319 r->info &= IPFW_ONEPASS; /* keep this info */
320 r->info |= dir ? IPFW_INFO_IN : IPFW_INFO_OUT;
321 m_tag_prepend(m, tag);
322
323 } else
324 if ((m = m_dup(*m0, M_NOWAIT)) == NULL)
325 return (ENOMEM); /* which is ignored */
326
327 if (m->m_len < sizeof(struct ip) &&
328 (m = m_pullup(m, sizeof(struct ip))) == NULL)
329 return (EINVAL);
330
331 ip = mtod(m, struct ip *);
332
333 NG_SEND_DATA_ONLY(error, hook, m);
334
335 return (error);
336 }
337
338 static int
339 ng_ipfw_shutdown(node_p node)
340 {
341
342 /*
343 * After our single node has been removed,
344 * the only thing that can be done is
345 * 'kldunload ng_ipfw.ko'
346 */
347 ng_ipfw_input_p = NULL;
348 NG_NODE_UNREF(node);
349 return (0);
350 }
351
352 static int
353 ng_ipfw_disconnect(hook_p hook)
354 {
355 const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
356
357 free(hpriv, M_NETGRAPH);
358 NG_HOOK_SET_PRIVATE(hook, NULL);
359
360 return (0);
361 }
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