FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_gre.c
1 /* $NetBSD: ip_gre.c,v 1.29 2003/09/05 23:02:43 itojun Exp $ */
2
3 /*-
4 * Copyright (c) 1998 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Heiko W.Rupp <hwr@pilhuhn.de>
9 *
10 * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the NetBSD
23 * Foundation, Inc. and its contributors.
24 * 4. Neither the name of The NetBSD Foundation nor the names of its
25 * contributors may be used to endorse or promote products derived
26 * from this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGE.
39 */
40
41 /*
42 * deencapsulate tunneled packets and send them on
43 * output half is in net/if_gre.[ch]
44 * This currently handles IPPROTO_GRE, IPPROTO_MOBILE
45 */
46
47 #include <sys/cdefs.h>
48 __FBSDID("$FreeBSD: src/sys/netinet/ip_gre.c,v 1.26 2008/07/04 21:01:30 gonzo Exp $");
49
50 #include "opt_inet.h"
51 #include "opt_atalk.h"
52 #include "opt_inet6.h"
53
54 #include <sys/param.h>
55 #include <sys/systm.h>
56 #include <sys/mbuf.h>
57 #include <sys/socket.h>
58 #include <sys/socketvar.h>
59 #include <sys/protosw.h>
60 #include <sys/errno.h>
61 #include <sys/time.h>
62 #include <sys/kernel.h>
63 #include <sys/syslog.h>
64 #include <net/bpf.h>
65 #include <net/ethernet.h>
66 #include <net/if.h>
67 #include <net/netisr.h>
68 #include <net/route.h>
69 #include <net/raw_cb.h>
70
71 #ifdef INET
72 #include <netinet/in.h>
73 #include <netinet/in_var.h>
74 #include <netinet/in_systm.h>
75 #include <netinet/ip.h>
76 #include <netinet/ip_var.h>
77 #include <netinet/ip_gre.h>
78 #include <machine/in_cksum.h>
79 #else
80 #error ip_gre input without IP?
81 #endif
82
83 #ifdef NETATALK
84 #include <netatalk/at.h>
85 #include <netatalk/at_var.h>
86 #include <netatalk/at_extern.h>
87 #endif
88
89 /* Needs IP headers. */
90 #include <net/if_gre.h>
91
92 #include <machine/stdarg.h>
93
94 #if 1
95 void gre_inet_ntoa(struct in_addr in); /* XXX */
96 #endif
97
98 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t);
99
100 static struct mbuf *gre_input2(struct mbuf *, int, u_char);
101
102 /*
103 * De-encapsulate a packet and feed it back through ip input (this
104 * routine is called whenever IP gets a packet with proto type
105 * IPPROTO_GRE and a local destination address).
106 * This really is simple
107 */
108 void
109 gre_input(struct mbuf *m, int off)
110 {
111 int proto;
112
113 proto = (mtod(m, struct ip *))->ip_p;
114
115 m = gre_input2(m, off, proto);
116
117 /*
118 * If no matching tunnel that is up is found. We inject
119 * the mbuf to raw ip socket to see if anyone picks it up.
120 */
121 if (m != NULL)
122 rip_input(m, off);
123 }
124
125 /*
126 * Decapsulate. Does the real work and is called from gre_input()
127 * (above). Returns an mbuf back if packet is not yet processed,
128 * and NULL if it needs no further processing. proto is the protocol
129 * number of the "calling" foo_input() routine.
130 */
131 static struct mbuf *
132 gre_input2(struct mbuf *m ,int hlen, u_char proto)
133 {
134 struct greip *gip;
135 int isr;
136 struct gre_softc *sc;
137 u_int16_t flags;
138 u_int32_t af;
139
140 if ((sc = gre_lookup(m, proto)) == NULL) {
141 /* No matching tunnel or tunnel is down. */
142 return (m);
143 }
144
145 if (m->m_len < sizeof(*gip)) {
146 m = m_pullup(m, sizeof(*gip));
147 if (m == NULL)
148 return (NULL);
149 }
150 gip = mtod(m, struct greip *);
151
152 GRE2IFP(sc)->if_ipackets++;
153 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len;
154
155 switch (proto) {
156 case IPPROTO_GRE:
157 hlen += sizeof(struct gre_h);
158
159 /* process GRE flags as packet can be of variable len */
160 flags = ntohs(gip->gi_flags);
161
162 /* Checksum & Offset are present */
163 if ((flags & GRE_CP) | (flags & GRE_RP))
164 hlen += 4;
165 /* We don't support routing fields (variable length) */
166 if (flags & GRE_RP)
167 return (m);
168 if (flags & GRE_KP)
169 hlen += 4;
170 if (flags & GRE_SP)
171 hlen += 4;
172
173 switch (ntohs(gip->gi_ptype)) { /* ethertypes */
174 case WCCP_PROTOCOL_TYPE:
175 if (sc->wccp_ver == WCCP_V2)
176 hlen += 4;
177 /* FALLTHROUGH */
178 case ETHERTYPE_IP: /* shouldn't need a schednetisr(), */
179 isr = NETISR_IP;/* as we are in ip_input */
180 af = AF_INET;
181 break;
182 #ifdef INET6
183 case ETHERTYPE_IPV6:
184 isr = NETISR_IPV6;
185 af = AF_INET6;
186 break;
187 #endif
188 #ifdef NETATALK
189 case ETHERTYPE_ATALK:
190 isr = NETISR_ATALK1;
191 af = AF_APPLETALK;
192 break;
193 #endif
194 default:
195 /* Others not yet supported. */
196 return (m);
197 }
198 break;
199 default:
200 /* Others not yet supported. */
201 return (m);
202 }
203
204 if (hlen > m->m_pkthdr.len) {
205 m_freem(m);
206 return (NULL);
207 }
208 /* Unlike NetBSD, in FreeBSD m_adj() adjusts m->m_pkthdr.len as well */
209 m_adj(m, hlen);
210
211 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) {
212 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m);
213 }
214
215 m->m_pkthdr.rcvif = GRE2IFP(sc);
216
217 netisr_queue(isr, m);
218
219 /* Packet is done, no further processing needed. */
220 return (NULL);
221 }
222
223 /*
224 * input routine for IPPRPOTO_MOBILE
225 * This is a little bit diffrent from the other modes, as the
226 * encapsulating header was not prepended, but instead inserted
227 * between IP header and payload
228 */
229
230 void
231 gre_mobile_input(struct mbuf *m, int hlen)
232 {
233 struct ip *ip;
234 struct mobip_h *mip;
235 struct gre_softc *sc;
236 int msiz;
237
238 if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) {
239 /* No matching tunnel or tunnel is down. */
240 m_freem(m);
241 return;
242 }
243
244 if (m->m_len < sizeof(*mip)) {
245 m = m_pullup(m, sizeof(*mip));
246 if (m == NULL)
247 return;
248 }
249 ip = mtod(m, struct ip *);
250 mip = mtod(m, struct mobip_h *);
251
252 GRE2IFP(sc)->if_ipackets++;
253 GRE2IFP(sc)->if_ibytes += m->m_pkthdr.len;
254
255 if (ntohs(mip->mh.proto) & MOB_H_SBIT) {
256 msiz = MOB_H_SIZ_L;
257 mip->mi.ip_src.s_addr = mip->mh.osrc;
258 } else
259 msiz = MOB_H_SIZ_S;
260
261 if (m->m_len < (ip->ip_hl << 2) + msiz) {
262 m = m_pullup(m, (ip->ip_hl << 2) + msiz);
263 if (m == NULL)
264 return;
265 ip = mtod(m, struct ip *);
266 mip = mtod(m, struct mobip_h *);
267 }
268
269 mip->mi.ip_dst.s_addr = mip->mh.odst;
270 mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8);
271
272 if (gre_in_cksum((u_int16_t *)&mip->mh, msiz) != 0) {
273 m_freem(m);
274 return;
275 }
276
277 bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) +
278 (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2));
279 m->m_len -= msiz;
280 m->m_pkthdr.len -= msiz;
281
282 /*
283 * On FreeBSD, rip_input() supplies us with ip->ip_len
284 * already converted into host byteorder and also decreases
285 * it by the lengh of IP header, however, ip_input() expects
286 * that this field is in the original format (network byteorder
287 * and full size of IP packet), so that adjust accordingly.
288 */
289 ip->ip_len = htons(ip->ip_len + sizeof(struct ip) - msiz);
290
291 ip->ip_sum = 0;
292 ip->ip_sum = in_cksum(m, (ip->ip_hl << 2));
293
294 if (bpf_peers_present(GRE2IFP(sc)->if_bpf)) {
295 u_int32_t af = AF_INET;
296 bpf_mtap2(GRE2IFP(sc)->if_bpf, &af, sizeof(af), m);
297 }
298
299 m->m_pkthdr.rcvif = GRE2IFP(sc);
300
301 netisr_queue(NETISR_IP, m);
302 }
303
304 /*
305 * Find the gre interface associated with our src/dst/proto set.
306 *
307 * XXXRW: Need some sort of drain/refcount mechanism so that the softc
308 * reference remains valid after it's returned from gre_lookup(). Right
309 * now, I'm thinking it should be reference-counted with a gre_dropref()
310 * when the caller is done with the softc. This is complicated by how
311 * to handle destroying the gre softc; probably using a gre_drain() in
312 * in_gre.c during destroy.
313 */
314 static struct gre_softc *
315 gre_lookup(struct mbuf *m, u_int8_t proto)
316 {
317 struct ip *ip = mtod(m, struct ip *);
318 struct gre_softc *sc;
319
320 mtx_lock(&gre_mtx);
321 for (sc = LIST_FIRST(&gre_softc_list); sc != NULL;
322 sc = LIST_NEXT(sc, sc_list)) {
323 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) &&
324 (sc->g_src.s_addr == ip->ip_dst.s_addr) &&
325 (sc->g_proto == proto) &&
326 ((GRE2IFP(sc)->if_flags & IFF_UP) != 0)) {
327 mtx_unlock(&gre_mtx);
328 return (sc);
329 }
330 }
331 mtx_unlock(&gre_mtx);
332
333 return (NULL);
334 }
335
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