send.c revision 254523 
1/*-
2 * Copyright (c) 2009-2010 Ana Kukec <anchie@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
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/netinet6/send.c 254523 2013-08-19 13:27:32Z andre $");
29
30#include <sys/param.h>
31#include <sys/kernel.h>
32#include <sys/mbuf.h>
33#include <sys/module.h>
34#include <sys/priv.h>
35#include <sys/protosw.h>
36#include <sys/systm.h>
37#include <sys/socket.h>
38#include <sys/sockstate.h>
39#include <sys/sockbuf.h>
40#include <sys/socketvar.h>
41#include <sys/types.h>
42
43#include <net/route.h>
44#include <net/if.h>
45#include <net/if_var.h>
46#include <net/vnet.h>
47
48#include <netinet/in.h>
49#include <netinet/ip_var.h>
50#include <netinet/ip6.h>
51#include <netinet/icmp6.h>
52
53#include <netinet6/in6_var.h>
54#include <netinet6/nd6.h>
55#include <netinet6/scope6_var.h>
56#include <netinet6/send.h>
57
58static MALLOC_DEFINE(M_SEND, "send", "Secure Neighbour Discovery");
59
60/*
61 * The socket used to communicate with the SeND daemon.
62 */
63static VNET_DEFINE(struct socket *, send_so);
64#define	V_send_so	VNET(send_so)
65
66u_long	send_sendspace	= 8 * (1024 + sizeof(struct sockaddr_send));
67u_long	send_recvspace	= 9216;
68
69struct mtx	send_mtx;
70#define SEND_LOCK_INIT()	mtx_init(&send_mtx, "send_mtx", NULL, MTX_DEF)
71#define SEND_LOCK()		mtx_lock(&send_mtx)
72#define SEND_UNLOCK()		mtx_unlock(&send_mtx)
73#define SEND_LOCK_DESTROY()     mtx_destroy(&send_mtx)
74
75static int
76send_attach(struct socket *so, int proto, struct thread *td)
77{
78	int error;
79
80	SEND_LOCK();
81	if (V_send_so != NULL) {
82		SEND_UNLOCK();
83		return (EEXIST);
84	}
85
86	error = priv_check(td, PRIV_NETINET_RAW);
87	if (error) {
88		SEND_UNLOCK();
89		return(error);
90	}
91
92	if (proto != IPPROTO_SEND) {
93		SEND_UNLOCK();
94		return (EPROTONOSUPPORT);
95	}
96	error = soreserve(so, send_sendspace, send_recvspace);
97	if (error) {
98		SEND_UNLOCK();
99		return(error);
100	}
101
102	V_send_so = so;
103	SEND_UNLOCK();
104
105	return (0);
106}
107
108static int
109send_output(struct mbuf *m, struct ifnet *ifp, int direction)
110{
111	struct ip6_hdr *ip6;
112	struct sockaddr_in6 dst;
113	struct icmp6_hdr *icmp6;
114	int icmp6len;
115
116	/*
117	 * Receive incoming (SeND-protected) or outgoing traffic
118	 * (SeND-validated) from the SeND user space application.
119	 */
120
121	switch (direction) {
122	case SND_IN:
123		if (m->m_len < (sizeof(struct ip6_hdr) +
124		    sizeof(struct icmp6_hdr))) {
125			m = m_pullup(m, sizeof(struct ip6_hdr) +
126			    sizeof(struct icmp6_hdr));
127			if (!m)
128				return (ENOBUFS);
129		}
130
131		/* Before passing off the mbuf record the proper interface. */
132		m->m_pkthdr.rcvif = ifp;
133
134		if (m->m_flags & M_PKTHDR)
135			icmp6len = m->m_pkthdr.len - sizeof(struct ip6_hdr);
136		else
137			panic("Doh! not the first mbuf.");
138
139		ip6 = mtod(m, struct ip6_hdr *);
140		icmp6 = (struct icmp6_hdr *)(ip6 + 1);
141
142		/*
143		 * Output the packet as icmp6.c:icpm6_input() would do.
144		 * The mbuf is always consumed, so we do not have to
145		 * care about that.
146		 */
147		switch (icmp6->icmp6_type) {
148		case ND_NEIGHBOR_SOLICIT:
149			nd6_ns_input(m, sizeof(struct ip6_hdr), icmp6len);
150			break;
151		case ND_NEIGHBOR_ADVERT:
152			nd6_na_input(m, sizeof(struct ip6_hdr), icmp6len);
153			break;
154		case ND_REDIRECT:
155			icmp6_redirect_input(m, sizeof(struct ip6_hdr));
156			break;
157		case ND_ROUTER_SOLICIT:
158			nd6_rs_input(m, sizeof(struct ip6_hdr), icmp6len);
159			break;
160		case ND_ROUTER_ADVERT:
161			nd6_ra_input(m, sizeof(struct ip6_hdr), icmp6len);
162			break;
163		default:
164			return (ENOSYS);
165		}
166		return (0);
167
168	case SND_OUT:
169		if (m->m_len < sizeof(struct ip6_hdr)) {
170			m = m_pullup(m, sizeof(struct ip6_hdr));
171			if (!m)
172				return (ENOBUFS);
173		}
174		ip6 = mtod(m, struct ip6_hdr *);
175		if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
176			m->m_flags |= M_MCAST;
177
178		bzero(&dst, sizeof(dst));
179		dst.sin6_family = AF_INET6;
180		dst.sin6_len = sizeof(dst);
181		dst.sin6_addr = ip6->ip6_dst;
182
183		m_clrprotoflags(m);	/* Avoid confusing lower layers. */
184
185		/*
186		 * Output the packet as nd6.c:nd6_output_lle() would do.
187		 * The mbuf is always consumed, so we do not have to care
188		 * about that.
189		 * XXX-BZ as we added data, what about fragmenting,
190		 * if now needed?
191		 */
192		int error;
193		error = ((*ifp->if_output)(ifp, m, (struct sockaddr *)&dst,
194		    NULL));
195		if (error)
196			error = ENOENT;
197		return (error);
198
199	default:
200		panic("%s: direction %d neither SND_IN nor SND_OUT.",
201		     __func__, direction);
202	}
203}
204
205/*
206 * Receive a SeND message from user space to be either send out by the kernel
207 * or, with SeND ICMPv6 options removed, to be further processed by the icmp6
208 * input path.
209 */
210static int
211send_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
212    struct mbuf *control, struct thread *td)
213{
214	struct sockaddr_send *sendsrc;
215	struct ifnet *ifp;
216	int error;
217
218	KASSERT(V_send_so == so, ("%s: socket %p not send socket %p",
219		__func__, so, V_send_so));
220
221	sendsrc = (struct sockaddr_send *)nam;
222	ifp = ifnet_byindex_ref(sendsrc->send_ifidx);
223	if (ifp == NULL) {
224		error = ENETUNREACH;
225		goto err;
226	}
227
228	error = send_output(m, ifp, sendsrc->send_direction);
229	if_rele(ifp);
230	m = NULL;
231
232err:
233	if (m != NULL)
234		m_freem(m);
235	return (error);
236}
237
238static void
239send_close(struct socket *so)
240{
241
242	SEND_LOCK();
243	if (V_send_so)
244		V_send_so = NULL;
245	SEND_UNLOCK();
246}
247
248/*
249 * Send a SeND message to user space, that was either received and has to be
250 * validated or was about to be send out and has to be handled by the SEND
251 * daemon adding SeND ICMPv6 options.
252 */
253static int
254send_input(struct mbuf *m, struct ifnet *ifp, int direction, int msglen __unused)
255{
256	struct ip6_hdr *ip6;
257	struct sockaddr_send sendsrc;
258
259	SEND_LOCK();
260	if (V_send_so == NULL) {
261		SEND_UNLOCK();
262		return (-1);
263	}
264
265	/*
266	 * Make sure to clear any possible internally embedded scope before
267	 * passing the packet to user space for SeND cryptographic signature
268	 * validation to succeed.
269	 */
270	ip6 = mtod(m, struct ip6_hdr *);
271	in6_clearscope(&ip6->ip6_src);
272	in6_clearscope(&ip6->ip6_dst);
273
274	bzero(&sendsrc, sizeof(sendsrc));
275	sendsrc.send_len = sizeof(sendsrc);
276	sendsrc.send_family = AF_INET6;
277	sendsrc.send_direction = direction;
278	sendsrc.send_ifidx = ifp->if_index;
279
280	/*
281	 * Send incoming or outgoing traffic to user space either to be
282	 * protected (outgoing) or validated (incoming) according to rfc3971.
283	 */
284	SOCKBUF_LOCK(&V_send_so->so_rcv);
285	if (sbappendaddr_locked(&V_send_so->so_rcv,
286	    (struct sockaddr *)&sendsrc, m, NULL) == 0) {
287		SOCKBUF_UNLOCK(&V_send_so->so_rcv);
288		/* XXX stats. */
289		m_freem(m);
290	} else {
291		sorwakeup_locked(V_send_so);
292	}
293
294	SEND_UNLOCK();
295	return (0);
296}
297
298struct pr_usrreqs send_usrreqs = {
299	.pru_attach =		send_attach,
300	.pru_send =		send_send,
301	.pru_detach =		send_close
302};
303struct protosw send_protosw = {
304	.pr_type =		SOCK_RAW,
305	.pr_flags =		PR_ATOMIC|PR_ADDR,
306	.pr_protocol =		IPPROTO_SEND,
307	.pr_usrreqs =		&send_usrreqs
308};
309
310static int
311send_modevent(module_t mod, int type, void *unused)
312{
313#ifdef __notyet__
314	VNET_ITERATOR_DECL(vnet_iter);
315#endif
316	int error;
317
318	switch (type) {
319	case MOD_LOAD:
320		SEND_LOCK_INIT();
321
322		error = pf_proto_register(PF_INET6, &send_protosw);
323		if (error != 0) {
324			printf("%s:%d: MOD_LOAD pf_proto_register(): %d\n",
325			   __func__, __LINE__, error);
326			SEND_LOCK_DESTROY();
327			break;
328		}
329		send_sendso_input_hook = send_input;
330		break;
331	case MOD_UNLOAD:
332		/* Do not allow unloading w/o locking. */
333		return (EBUSY);
334#ifdef __notyet__
335		VNET_LIST_RLOCK_NOSLEEP();
336		SEND_LOCK();
337		VNET_FOREACH(vnet_iter) {
338			CURVNET_SET(vnet_iter);
339			if (V_send_so != NULL) {
340				CURVNET_RESTORE();
341				SEND_UNLOCK();
342				VNET_LIST_RUNLOCK_NOSLEEP();
343				return (EBUSY);
344			}
345			CURVNET_RESTORE();
346		}
347		SEND_UNLOCK();
348		VNET_LIST_RUNLOCK_NOSLEEP();
349		error = pf_proto_unregister(PF_INET6, IPPROTO_SEND, SOCK_RAW);
350		if (error == 0)
351			SEND_LOCK_DESTROY();
352		send_sendso_input_hook = NULL;
353		break;
354#endif
355	default:
356		error = 0;
357		break;
358	}
359
360	return (error);
361}
362
363static moduledata_t sendmod = {
364	"send",
365	send_modevent,
366	0
367};
368
369DECLARE_MODULE(send, sendmod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
370