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 * $FreeBSD$
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
63static int		ng_ipfw_mod_event(module_t mod, int event, void *data);
64static ng_constructor_t	ng_ipfw_constructor;
65static ng_shutdown_t	ng_ipfw_shutdown;
66static ng_newhook_t	ng_ipfw_newhook;
67static ng_connect_t	ng_ipfw_connect;
68static ng_findhook_t	ng_ipfw_findhook;
69static ng_rcvdata_t	ng_ipfw_rcvdata;
70static ng_disconnect_t	ng_ipfw_disconnect;
71
72static hook_p		ng_ipfw_findhook1(node_p, u_int16_t );
73static int		ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
74			    int);
75
76/* We have only one node */
77static node_p	fw_node;
78
79/* Netgraph node type descriptor */
80static 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};
92NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
93MODULE_DEPEND(ng_ipfw, ipfw, 3, 3, 3);
94
95/* Information we store for each hook */
96struct ng_ipfw_hook_priv {
97        hook_p		hook;
98	u_int16_t	rulenum;
99};
100typedef struct ng_ipfw_hook_priv *hpriv_p;
101
102static int
103ng_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
146static int
147ng_ipfw_constructor(node_p node)
148{
149	return (EINVAL);	/* Only one node */
150}
151
152static int
153ng_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] == '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 */
191static int
192ng_ipfw_connect(hook_p hook)
193{
194	NG_HOOK_FORCE_QUEUE(hook);
195	return (0);
196}
197
198/* Look up hook by name */
199static hook_p
200ng_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 */
212static hook_p
213ng_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
228static int
229ng_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
285static int
286ng_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
338static int
339ng_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
352static int
353ng_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}
362