xref: /dragonfly/sys/netgraph7/ng_ipfw.c (revision fb151170) 
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 }
341