1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright 2005, Gleb Smirnoff <glebius@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#include "opt_inet.h"
32#include "opt_inet6.h"
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/kernel.h>
37#include <sys/lock.h>
38#include <sys/mbuf.h>
39#include <sys/malloc.h>
40#include <sys/ctype.h>
41#include <sys/errno.h>
42#include <sys/rwlock.h>
43#include <sys/socket.h>
44#include <sys/syslog.h>
45
46#include <net/if.h>
47#include <net/if_var.h>
48
49#include <netinet/in.h>
50#include <netinet/in_systm.h>
51#include <netinet/in_var.h>
52#include <netinet/ip_var.h>
53#include <netinet/ip_fw.h>
54#include <netinet/ip.h>
55#include <netinet/ip6.h>
56#include <netinet6/ip6_var.h>
57
58#include <netpfil/ipfw/ip_fw_private.h>
59
60#include <netgraph/ng_message.h>
61#include <netgraph/ng_parse.h>
62#include <netgraph/ng_ipfw.h>
63#include <netgraph/netgraph.h>
64
65static int		ng_ipfw_mod_event(module_t mod, int event, void *data);
66static ng_constructor_t	ng_ipfw_constructor;
67static ng_shutdown_t	ng_ipfw_shutdown;
68static ng_newhook_t	ng_ipfw_newhook;
69static ng_connect_t	ng_ipfw_connect;
70static ng_findhook_t	ng_ipfw_findhook;
71static ng_rcvdata_t	ng_ipfw_rcvdata;
72static ng_disconnect_t	ng_ipfw_disconnect;
73
74static hook_p		ng_ipfw_findhook1(node_p, u_int16_t );
75static int		ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
76			    int);
77
78/* We have only one node */
79static node_p	fw_node;
80
81/* Netgraph node type descriptor */
82static struct ng_type ng_ipfw_typestruct = {
83	.version =	NG_ABI_VERSION,
84	.name =		NG_IPFW_NODE_TYPE,
85	.mod_event =	ng_ipfw_mod_event,
86	.constructor =	ng_ipfw_constructor,
87	.shutdown =	ng_ipfw_shutdown,
88	.newhook =	ng_ipfw_newhook,
89	.connect =	ng_ipfw_connect,
90	.findhook =	ng_ipfw_findhook,
91	.rcvdata =	ng_ipfw_rcvdata,
92	.disconnect =	ng_ipfw_disconnect,
93};
94NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
95MODULE_DEPEND(ng_ipfw, ipfw, 3, 3, 3);
96
97/* Information we store for each hook */
98struct ng_ipfw_hook_priv {
99        hook_p		hook;
100	u_int16_t	rulenum;
101};
102typedef struct ng_ipfw_hook_priv *hpriv_p;
103
104static int
105ng_ipfw_mod_event(module_t mod, int event, void *data)
106{
107	int error = 0;
108
109	switch (event) {
110	case MOD_LOAD:
111
112		if (ng_ipfw_input_p != NULL) {
113			error = EEXIST;
114			break;
115		}
116
117		/* Setup node without any private data */
118		if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
119		    != 0) {
120			log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
121                	break;
122		}
123
124		/* Try to name node */
125		if (ng_name_node(fw_node, "ipfw") != 0)
126			log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
127			    __func__);
128
129		/* Register hook */
130		ng_ipfw_input_p = ng_ipfw_input;
131		break;
132
133	case MOD_UNLOAD:
134		 /*
135		  * This won't happen if a node exists.
136		  * ng_ipfw_input_p is already cleared.
137		  */
138		break;
139
140	default:
141		error = EOPNOTSUPP;
142		break;
143	}
144
145	return (error);
146}
147
148static int
149ng_ipfw_constructor(node_p node)
150{
151	return (EINVAL);	/* Only one node */
152}
153
154static int
155ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
156{
157	hpriv_p	hpriv;
158	u_int16_t rulenum;
159	const char *cp;
160	char *endptr;
161
162	/* Protect from leading zero */
163	if (name[0] == '0' && name[1] != '\0')
164		return (EINVAL);
165
166	/* Check that name contains only digits */
167	for (cp = name; *cp != '\0'; cp++)
168		if (!isdigit(*cp))
169			return (EINVAL);
170
171	/* Convert it to integer */
172	rulenum = (u_int16_t)strtol(name, &endptr, 10);
173	if (*endptr != '\0')
174		return (EINVAL);
175
176	/* Allocate memory for this hook's private data */
177	hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
178	if (hpriv== NULL)
179		return (ENOMEM);
180
181	hpriv->hook = hook;
182	hpriv->rulenum = rulenum;
183
184	NG_HOOK_SET_PRIVATE(hook, hpriv);
185
186	return(0);
187}
188
189/*
190 * Set hooks into queueing mode, to avoid recursion between
191 * netgraph layer and ip_{input,output}.
192 */
193static int
194ng_ipfw_connect(hook_p hook)
195{
196	NG_HOOK_FORCE_QUEUE(hook);
197	return (0);
198}
199
200/* Look up hook by name */
201static hook_p
202ng_ipfw_findhook(node_p node, const char *name)
203{
204	u_int16_t n;	/* numeric representation of hook */
205	char *endptr;
206
207	n = (u_int16_t)strtol(name, &endptr, 10);
208	if (*endptr != '\0')
209		return NULL;
210	return ng_ipfw_findhook1(node, n);
211}
212
213/* Look up hook by rule number */
214static hook_p
215ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
216{
217	hook_p	hook;
218	hpriv_p	hpriv;
219
220	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
221		hpriv = NG_HOOK_PRIVATE(hook);
222		if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
223                        return (hook);
224	}
225
226	return (NULL);
227}
228
229
230static int
231ng_ipfw_rcvdata(hook_p hook, item_p item)
232{
233	struct m_tag *tag;
234	struct ipfw_rule_ref *r;
235	struct mbuf *m;
236	struct ip *ip;
237
238	NGI_GET_M(item, m);
239	NG_FREE_ITEM(item);
240
241	tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
242	if (tag == NULL) {
243		NG_FREE_M(m);
244		return (EINVAL);	/* XXX: find smth better */
245	}
246
247	if (m->m_len < sizeof(struct ip) &&
248	    (m = m_pullup(m, sizeof(struct ip))) == NULL)
249		return (ENOBUFS);
250
251	ip = mtod(m, struct ip *);
252
253	r = (struct ipfw_rule_ref *)(tag + 1);
254	if (r->info & IPFW_INFO_IN) {
255		switch (ip->ip_v) {
256#ifdef INET
257		case IPVERSION:
258			ip_input(m);
259			return (0);
260#endif
261#ifdef INET6
262		case IPV6_VERSION >> 4:
263			ip6_input(m);
264			return (0);
265#endif
266		}
267	} else {
268		switch (ip->ip_v) {
269#ifdef INET
270		case IPVERSION:
271			return (ip_output(m, NULL, NULL, IP_FORWARDING,
272			    NULL, NULL));
273#endif
274#ifdef INET6
275		case IPV6_VERSION >> 4:
276			return (ip6_output(m, NULL, NULL, 0, NULL,
277			    NULL, NULL));
278#endif
279		}
280	}
281
282	/* unknown IP protocol version */
283	NG_FREE_M(m);
284	return (EPROTONOSUPPORT);
285}
286
287static int
288ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee)
289{
290	struct mbuf *m;
291	struct ip *ip;
292	hook_p	hook;
293	int error = 0;
294
295	/*
296	 * Node must be loaded and corresponding hook must be present.
297	 */
298	if (fw_node == NULL ||
299	   (hook = ng_ipfw_findhook1(fw_node, fwa->rule.info)) == NULL)
300		return (ESRCH);		/* no hook associated with this rule */
301
302	/*
303	 * We have two modes: in normal mode we add a tag to packet, which is
304	 * important to return packet back to IP stack. In tee mode we make
305	 * a copy of a packet and forward it into netgraph without a tag.
306	 */
307	if (tee == 0) {
308		struct m_tag *tag;
309		struct ipfw_rule_ref *r;
310		m = *m0;
311		*m0 = NULL;	/* it belongs now to netgraph */
312
313		tag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(*r),
314			M_NOWAIT|M_ZERO);
315		if (tag == NULL) {
316			m_freem(m);
317			return (ENOMEM);
318		}
319		r = (struct ipfw_rule_ref *)(tag + 1);
320		*r = fwa->rule;
321		r->info &= IPFW_ONEPASS;  /* keep this info */
322		r->info |= dir ? IPFW_INFO_IN : IPFW_INFO_OUT;
323		m_tag_prepend(m, tag);
324
325	} else
326		if ((m = m_dup(*m0, M_NOWAIT)) == NULL)
327			return (ENOMEM);	/* which is ignored */
328
329	if (m->m_len < sizeof(struct ip) &&
330	    (m = m_pullup(m, sizeof(struct ip))) == NULL)
331		return (EINVAL);
332
333	ip = mtod(m, struct ip *);
334
335	NG_SEND_DATA_ONLY(error, hook, m);
336
337	return (error);
338}
339
340static int
341ng_ipfw_shutdown(node_p node)
342{
343
344	/*
345	 * After our single node has been removed,
346	 * the only thing that can be done is
347	 * 'kldunload ng_ipfw.ko'
348	 */
349	ng_ipfw_input_p = NULL;
350	NG_NODE_UNREF(node);
351	return (0);
352}
353
354static int
355ng_ipfw_disconnect(hook_p hook)
356{
357	const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
358
359	free(hpriv, M_NETGRAPH);
360	NG_HOOK_SET_PRIVATE(hook, NULL);
361
362	return (0);
363}
364