FreeBSD/Linux Kernel Cross Reference
sys/net/if_enc.c
1 /*-
2 * Copyright (c) 2006 The FreeBSD Project.
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 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: releng/10.1/sys/net/if_enc.c 255926 2013-09-28 14:14:23Z glebius $
28 */
29
30 #include "opt_inet.h"
31 #include "opt_inet6.h"
32 #include "opt_enc.h"
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/mbuf.h>
39 #include <sys/module.h>
40 #include <machine/bus.h>
41 #include <sys/rman.h>
42 #include <sys/socket.h>
43 #include <sys/sockio.h>
44 #include <sys/sysctl.h>
45
46 #include <net/if.h>
47 #include <net/if_clone.h>
48 #include <net/if_types.h>
49 #include <net/pfil.h>
50 #include <net/route.h>
51 #include <net/netisr.h>
52 #include <net/bpf.h>
53 #include <net/vnet.h>
54
55 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 #include <netinet/ip_var.h>
59 #include <netinet/in_var.h>
60
61 #ifdef INET6
62 #include <netinet/ip6.h>
63 #include <netinet6/ip6_var.h>
64 #endif
65
66 #include <netipsec/ipsec.h>
67 #include <netipsec/xform.h>
68
69 #define ENCMTU (1024+512)
70
71 /* XXX this define must have the same value as in OpenBSD */
72 #define M_CONF 0x0400 /* payload was encrypted (ESP-transport) */
73 #define M_AUTH 0x0800 /* payload was authenticated (AH or ESP auth) */
74 #define M_AUTH_AH 0x2000 /* header was authenticated (AH) */
75
76 struct enchdr {
77 u_int32_t af;
78 u_int32_t spi;
79 u_int32_t flags;
80 };
81
82 struct ifnet *encif;
83 static struct mtx enc_mtx;
84
85 struct enc_softc {
86 struct ifnet *sc_ifp;
87 };
88
89 static int enc_ioctl(struct ifnet *, u_long, caddr_t);
90 static int enc_output(struct ifnet *ifp, struct mbuf *m,
91 const struct sockaddr *dst, struct route *ro);
92 static int enc_clone_create(struct if_clone *, int, caddr_t);
93 static void enc_clone_destroy(struct ifnet *);
94 static struct if_clone *enc_cloner;
95 static const char encname[] = "enc";
96
97 /*
98 * Sysctls.
99 */
100
101 /*
102 * Before and after are relative to when we are stripping the
103 * outer IP header.
104 */
105 static SYSCTL_NODE(_net, OID_AUTO, enc, CTLFLAG_RW, 0, "enc sysctl");
106
107 static SYSCTL_NODE(_net_enc, OID_AUTO, in, CTLFLAG_RW, 0, "enc input sysctl");
108 static int ipsec_filter_mask_in = ENC_BEFORE;
109 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW,
110 &ipsec_filter_mask_in, 0, "IPsec input firewall filter mask");
111 static int ipsec_bpf_mask_in = ENC_BEFORE;
112 SYSCTL_INT(_net_enc_in, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW,
113 &ipsec_bpf_mask_in, 0, "IPsec input bpf mask");
114
115 static SYSCTL_NODE(_net_enc, OID_AUTO, out, CTLFLAG_RW, 0, "enc output sysctl");
116 static int ipsec_filter_mask_out = ENC_BEFORE;
117 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_filter_mask, CTLFLAG_RW,
118 &ipsec_filter_mask_out, 0, "IPsec output firewall filter mask");
119 static int ipsec_bpf_mask_out = ENC_BEFORE|ENC_AFTER;
120 SYSCTL_INT(_net_enc_out, OID_AUTO, ipsec_bpf_mask, CTLFLAG_RW,
121 &ipsec_bpf_mask_out, 0, "IPsec output bpf mask");
122
123 static void
124 enc_clone_destroy(struct ifnet *ifp)
125 {
126 KASSERT(ifp != encif, ("%s: destroying encif", __func__));
127
128 bpfdetach(ifp);
129 if_detach(ifp);
130 if_free(ifp);
131 }
132
133 static int
134 enc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
135 {
136 struct ifnet *ifp;
137 struct enc_softc *sc;
138
139 sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
140 ifp = sc->sc_ifp = if_alloc(IFT_ENC);
141 if (ifp == NULL) {
142 free(sc, M_DEVBUF);
143 return (ENOSPC);
144 }
145
146 if_initname(ifp, encname, unit);
147 ifp->if_mtu = ENCMTU;
148 ifp->if_ioctl = enc_ioctl;
149 ifp->if_output = enc_output;
150 ifp->if_snd.ifq_maxlen = ifqmaxlen;
151 ifp->if_softc = sc;
152 if_attach(ifp);
153 bpfattach(ifp, DLT_ENC, sizeof(struct enchdr));
154
155 mtx_lock(&enc_mtx);
156 /* grab a pointer to enc0, ignore the rest */
157 if (encif == NULL)
158 encif = ifp;
159 mtx_unlock(&enc_mtx);
160
161 return (0);
162 }
163
164 static int
165 enc_modevent(module_t mod, int type, void *data)
166 {
167 switch (type) {
168 case MOD_LOAD:
169 mtx_init(&enc_mtx, "enc mtx", NULL, MTX_DEF);
170 enc_cloner = if_clone_simple(encname, enc_clone_create,
171 enc_clone_destroy, 1);
172 break;
173 case MOD_UNLOAD:
174 printf("enc module unload - not possible for this module\n");
175 return (EINVAL);
176 default:
177 return (EOPNOTSUPP);
178 }
179 return (0);
180 }
181
182 static moduledata_t enc_mod = {
183 "if_enc",
184 enc_modevent,
185 0
186 };
187
188 DECLARE_MODULE(if_enc, enc_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
189
190 static int
191 enc_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
192 struct route *ro)
193 {
194 m_freem(m);
195 return (0);
196 }
197
198 /*
199 * Process an ioctl request.
200 */
201 /* ARGSUSED */
202 static int
203 enc_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
204 {
205 int error = 0;
206
207 mtx_lock(&enc_mtx);
208
209 switch (cmd) {
210
211 case SIOCSIFFLAGS:
212 if (ifp->if_flags & IFF_UP)
213 ifp->if_drv_flags |= IFF_DRV_RUNNING;
214 else
215 ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
216
217 break;
218
219 default:
220 error = EINVAL;
221 }
222
223 mtx_unlock(&enc_mtx);
224 return (error);
225 }
226
227 int
228 ipsec_filter(struct mbuf **mp, int dir, int flags)
229 {
230 int error, i;
231 struct ip *ip;
232
233 KASSERT(encif != NULL, ("%s: encif is null", __func__));
234 KASSERT(flags & (ENC_IN|ENC_OUT),
235 ("%s: invalid flags: %04x", __func__, flags));
236
237 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0)
238 return (0);
239
240 if (flags & ENC_IN) {
241 if ((flags & ipsec_filter_mask_in) == 0)
242 return (0);
243 } else {
244 if ((flags & ipsec_filter_mask_out) == 0)
245 return (0);
246 }
247
248 /* Skip pfil(9) if no filters are loaded */
249 if (1
250 #ifdef INET
251 && !PFIL_HOOKED(&V_inet_pfil_hook)
252 #endif
253 #ifdef INET6
254 && !PFIL_HOOKED(&V_inet6_pfil_hook)
255 #endif
256 ) {
257 return (0);
258 }
259
260 i = min((*mp)->m_pkthdr.len, max_protohdr);
261 if ((*mp)->m_len < i) {
262 *mp = m_pullup(*mp, i);
263 if (*mp == NULL) {
264 printf("%s: m_pullup failed\n", __func__);
265 return (-1);
266 }
267 }
268
269 error = 0;
270 ip = mtod(*mp, struct ip *);
271 switch (ip->ip_v) {
272 #ifdef INET
273 case 4:
274 error = pfil_run_hooks(&V_inet_pfil_hook, mp,
275 encif, dir, NULL);
276 break;
277 #endif
278 #ifdef INET6
279 case 6:
280 error = pfil_run_hooks(&V_inet6_pfil_hook, mp,
281 encif, dir, NULL);
282 break;
283 #endif
284 default:
285 printf("%s: unknown IP version\n", __func__);
286 }
287
288 /*
289 * If the mbuf was consumed by the filter for requeueing (dummynet, etc)
290 * then error will be zero but we still want to return an error to our
291 * caller so the null mbuf isn't forwarded further.
292 */
293 if (*mp == NULL && error == 0)
294 return (-1); /* Consumed by the filter */
295 if (*mp == NULL)
296 return (error);
297 if (error != 0)
298 goto bad;
299
300 return (error);
301
302 bad:
303 m_freem(*mp);
304 *mp = NULL;
305 return (error);
306 }
307
308 void
309 ipsec_bpf(struct mbuf *m, struct secasvar *sav, int af, int flags)
310 {
311 int mflags;
312 struct enchdr hdr;
313
314 KASSERT(encif != NULL, ("%s: encif is null", __func__));
315 KASSERT(flags & (ENC_IN|ENC_OUT),
316 ("%s: invalid flags: %04x", __func__, flags));
317
318 if ((encif->if_drv_flags & IFF_DRV_RUNNING) == 0)
319 return;
320
321 if (flags & ENC_IN) {
322 if ((flags & ipsec_bpf_mask_in) == 0)
323 return;
324 } else {
325 if ((flags & ipsec_bpf_mask_out) == 0)
326 return;
327 }
328
329 if (bpf_peers_present(encif->if_bpf)) {
330 mflags = 0;
331 hdr.spi = 0;
332 if (!sav) {
333 struct m_tag *mtag;
334 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
335 if (mtag != NULL) {
336 struct tdb_ident *tdbi;
337 tdbi = (struct tdb_ident *) (mtag + 1);
338 if (tdbi->alg_enc != SADB_EALG_NONE)
339 mflags |= M_CONF;
340 if (tdbi->alg_auth != SADB_AALG_NONE)
341 mflags |= M_AUTH;
342 hdr.spi = tdbi->spi;
343 }
344 } else {
345 if (sav->alg_enc != SADB_EALG_NONE)
346 mflags |= M_CONF;
347 if (sav->alg_auth != SADB_AALG_NONE)
348 mflags |= M_AUTH;
349 hdr.spi = sav->spi;
350 }
351
352 /*
353 * We need to prepend the address family as a four byte
354 * field. Cons up a dummy header to pacify bpf. This
355 * is safe because bpf will only read from the mbuf
356 * (i.e., it won't try to free it or keep a pointer a
357 * to it).
358 */
359 hdr.af = af;
360 /* hdr.spi already set above */
361 hdr.flags = mflags;
362
363 bpf_mtap2(encif->if_bpf, &hdr, sizeof(hdr), m);
364 }
365 }
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