FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_gre.c
1 /* $NetBSD: ip_gre.c,v 1.21 2002/08/14 00:23:30 itojun Exp $ */
2 /* $FreeBSD: releng/5.2/sys/netinet/ip_gre.c 111926 2003-03-05 19:24:24Z peter $ */
3
4 /*
5 * Copyright (c) 1998 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Heiko W.Rupp <hwr@pilhuhn.de>
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 /*
41 * deencapsulate tunneled packets and send them on
42 * output half is in net/if_gre.[ch]
43 * This currently handles IPPROTO_GRE, IPPROTO_MOBILE
44 */
45
46 #include "opt_inet.h"
47 #include "opt_atalk.h"
48
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/mbuf.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/protosw.h>
55 #include <sys/errno.h>
56 #include <sys/time.h>
57 #include <sys/kernel.h>
58 #include <sys/syslog.h>
59 #include <net/bpf.h>
60 #include <net/ethernet.h>
61 #include <net/if.h>
62 #include <net/netisr.h>
63 #include <net/route.h>
64 #include <net/raw_cb.h>
65
66 #ifdef INET
67 #include <netinet/in.h>
68 #include <netinet/in_var.h>
69 #include <netinet/in_systm.h>
70 #include <netinet/ip.h>
71 #include <netinet/ip_var.h>
72 #include <netinet/ip_gre.h>
73 #include <machine/in_cksum.h>
74 #else
75 #error ip_gre input without IP?
76 #endif
77
78 #ifdef NETATALK
79 #include <netatalk/at.h>
80 #include <netatalk/at_var.h>
81 #include <netatalk/at_extern.h>
82 #endif
83
84 /* Needs IP headers. */
85 #include <net/if_gre.h>
86
87 #include <machine/stdarg.h>
88
89 #if 1
90 void gre_inet_ntoa(struct in_addr in); /* XXX */
91 #endif
92
93 static struct gre_softc *gre_lookup(struct mbuf *, u_int8_t);
94
95 static int gre_input2(struct mbuf *, int, u_char);
96
97 /*
98 * De-encapsulate a packet and feed it back through ip input (this
99 * routine is called whenever IP gets a packet with proto type
100 * IPPROTO_GRE and a local destination address).
101 * This really is simple
102 */
103 void
104 #if __STDC__
105 gre_input(struct mbuf *m, ...)
106 #else
107 gre_input(m, va_alist)
108 struct mbuf *m;
109 va_dcl
110 #endif
111 {
112 int off, ret, proto;
113 va_list ap;
114
115 va_start(ap, m);
116 off = va_arg(ap, int);
117 va_end(ap);
118 proto = (mtod(m, struct ip *))->ip_p;
119
120 ret = gre_input2(m, off, proto);
121 /*
122 * ret == 0 : packet not processed, meaning that
123 * no matching tunnel that is up is found.
124 * we inject it to raw ip socket to see if anyone picks it up.
125 */
126 if (ret == 0)
127 rip_input(m, off);
128 }
129
130 /*
131 * decapsulate.
132 * Does the real work and is called from gre_input() (above)
133 * returns 0 if packet is not yet processed
134 * and 1 if it needs no further processing
135 * proto is the protocol number of the "calling" foo_input()
136 * routine.
137 */
138
139 static int
140 gre_input2(struct mbuf *m ,int hlen, u_char proto)
141 {
142 struct greip *gip = mtod(m, struct greip *);
143 int isr;
144 struct gre_softc *sc;
145 u_short flags;
146
147 if ((sc = gre_lookup(m, proto)) == NULL) {
148 /* No matching tunnel or tunnel is down. */
149 return (0);
150 }
151
152 sc->sc_if.if_ipackets++;
153 sc->sc_if.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(0);
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 ETHERTYPE_IP: /* shouldn't need a schednetisr(), as */
175 case WCCP_PROTOCOL_TYPE: /* we are in ip_input */
176 isr = NETISR_IP;
177 break;
178 #ifdef NETATALK
179 case ETHERTYPE_ATALK:
180 isr = NETISR_ATALK1;
181 break;
182 #endif
183 case ETHERTYPE_IPV6:
184 /* FALLTHROUGH */
185 default: /* others not yet supported */
186 return(0);
187 }
188 break;
189 default:
190 /* others not yet supported */
191 return(0);
192 }
193
194 m->m_data += hlen;
195 m->m_len -= hlen;
196 m->m_pkthdr.len -= hlen;
197
198 if (sc->sc_if.if_bpf) {
199 struct mbuf m0;
200 u_int32_t af = AF_INET;
201
202 m0.m_next = m;
203 m0.m_len = 4;
204 m0.m_data = (char *)⁡
205
206 BPF_MTAP(&(sc->sc_if), &m0);
207 }
208
209 m->m_pkthdr.rcvif = &sc->sc_if;
210
211 netisr_dispatch(isr, m);
212
213 return(1); /* packet is done, no further processing needed */
214 }
215
216 /*
217 * input routine for IPPRPOTO_MOBILE
218 * This is a little bit diffrent from the other modes, as the
219 * encapsulating header was not prepended, but instead inserted
220 * between IP header and payload
221 */
222
223 void
224 #if __STDC__
225 gre_mobile_input(struct mbuf *m, ...)
226 #else
227 gre_mobile_input(m, va_alist)
228 struct mbuf *m;
229 va_dcl
230 #endif
231 {
232 struct ip *ip = mtod(m, struct ip *);
233 struct mobip_h *mip = mtod(m, struct mobip_h *);
234 struct gre_softc *sc;
235 int hlen;
236 va_list ap;
237 u_char osrc = 0;
238 int msiz;
239
240 va_start(ap,m);
241 hlen = va_arg(ap, int);
242 va_end(ap);
243
244 if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) {
245 /* No matching tunnel or tunnel is down. */
246 m_freem(m);
247 return;
248 }
249
250 sc->sc_if.if_ipackets++;
251 sc->sc_if.if_ibytes += m->m_pkthdr.len;
252
253 if(ntohs(mip->mh.proto) & MOB_H_SBIT) {
254 osrc = 1;
255 msiz = MOB_H_SIZ_L;
256 mip->mi.ip_src.s_addr = mip->mh.osrc;
257 } else {
258 msiz = MOB_H_SIZ_S;
259 }
260 mip->mi.ip_dst.s_addr = mip->mh.odst;
261 mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8);
262
263 if (gre_in_cksum((u_short*)&mip->mh,msiz) != 0) {
264 m_freem(m);
265 return;
266 }
267
268 bcopy((caddr_t)(ip) + (ip->ip_hl << 2) + msiz, (caddr_t)(ip) +
269 (ip->ip_hl << 2), m->m_len - msiz - (ip->ip_hl << 2));
270 m->m_len -= msiz;
271 m->m_pkthdr.len -= msiz;
272
273 /*
274 * On FreeBSD, rip_input() supplies us with ip->ip_len
275 * already converted into host byteorder and also decreases
276 * it by the lengh of IP header, however, ip_input() expects
277 * that this field is in the original format (network byteorder
278 * and full size of IP packet), so that adjust accordingly.
279 */
280 ip->ip_len = htons(ip->ip_len + sizeof(struct ip) - msiz);
281
282 ip->ip_sum = 0;
283 ip->ip_sum = in_cksum(m, (ip->ip_hl << 2));
284
285 if (sc->sc_if.if_bpf) {
286 struct mbuf m0;
287 u_int af = AF_INET;
288
289 m0.m_next = m;
290 m0.m_len = 4;
291 m0.m_data = (char *)⁡
292
293 BPF_MTAP(&(sc->sc_if), &m0);
294 }
295
296 m->m_pkthdr.rcvif = &sc->sc_if;
297
298 netisr_dispatch(NETISR_IP, m);
299 }
300
301 /*
302 * Find the gre interface associated with our src/dst/proto set.
303 */
304 static struct gre_softc *
305 gre_lookup(m, proto)
306 struct mbuf *m;
307 u_int8_t proto;
308 {
309 struct ip *ip = mtod(m, struct ip *);
310 struct gre_softc *sc;
311
312 for (sc = LIST_FIRST(&gre_softc_list); sc != NULL;
313 sc = LIST_NEXT(sc, sc_list)) {
314 if ((sc->g_dst.s_addr == ip->ip_src.s_addr) &&
315 (sc->g_src.s_addr == ip->ip_dst.s_addr) &&
316 (sc->g_proto == proto) &&
317 ((sc->sc_if.if_flags & IFF_UP) != 0))
318 return (sc);
319 }
320
321 return (NULL);
322 }
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