mpls_ttl.c revision 1.10 1 1.10 maxv /* $NetBSD: mpls_ttl.c,v 1.10 2018/01/19 10:54:31 maxv Exp $ */
2 1.1 kefren
3 1.9 maxv /*
4 1.1 kefren * Copyright (c) 2010 The NetBSD Foundation, Inc.
5 1.1 kefren * All rights reserved.
6 1.1 kefren *
7 1.1 kefren * This code is derived from software contributed to The NetBSD Foundation
8 1.1 kefren * by Public Access Networks Corporation ("Panix"). It was developed under
9 1.1 kefren * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
10 1.1 kefren *
11 1.1 kefren * This code is derived from software contributed to The NetBSD Foundation
12 1.1 kefren * by Jason R. Thorpe of Zembu Labs, Inc.
13 1.1 kefren *
14 1.1 kefren * This code is derived from software contributed to The NetBSD Foundation
15 1.1 kefren * by Mihai Chelaru <kefren (at) NetBSD.org>
16 1.1 kefren *
17 1.1 kefren * Redistribution and use in source and binary forms, with or without
18 1.1 kefren * modification, are permitted provided that the following conditions
19 1.1 kefren * are met:
20 1.1 kefren * 1. Redistributions of source code must retain the above copyright
21 1.1 kefren * notice, this list of conditions and the following disclaimer.
22 1.1 kefren * 2. Redistributions in binary form must reproduce the above copyright
23 1.1 kefren * notice, this list of conditions and the following disclaimer in the
24 1.1 kefren * documentation and/or other materials provided with the distribution.
25 1.1 kefren *
26 1.1 kefren * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 1.1 kefren * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 1.1 kefren * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 1.1 kefren * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 1.1 kefren * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 1.1 kefren * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 1.1 kefren * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 1.1 kefren * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 1.1 kefren * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 1.1 kefren * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 1.1 kefren * POSSIBILITY OF SUCH DAMAGE.
37 1.1 kefren */
38 1.1 kefren
39 1.1 kefren /*
40 1.10 maxv * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
41 1.10 maxv * All rights reserved.
42 1.10 maxv *
43 1.10 maxv * Redistribution and use in source and binary forms, with or without
44 1.10 maxv * modification, are permitted provided that the following conditions
45 1.10 maxv * are met:
46 1.10 maxv * 1. Redistributions of source code must retain the above copyright
47 1.10 maxv * notice, this list of conditions and the following disclaimer.
48 1.10 maxv * 2. Redistributions in binary form must reproduce the above copyright
49 1.10 maxv * notice, this list of conditions and the following disclaimer in the
50 1.10 maxv * documentation and/or other materials provided with the distribution.
51 1.10 maxv * 3. Neither the name of the project nor the names of its contributors
52 1.10 maxv * may be used to endorse or promote products derived from this software
53 1.10 maxv * without specific prior written permission.
54 1.10 maxv *
55 1.10 maxv * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
56 1.10 maxv * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57 1.10 maxv * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58 1.10 maxv * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
59 1.10 maxv * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60 1.10 maxv * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61 1.10 maxv * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62 1.10 maxv * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63 1.10 maxv * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64 1.10 maxv * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65 1.10 maxv * SUCH DAMAGE.
66 1.10 maxv */
67 1.10 maxv
68 1.10 maxv /*
69 1.1 kefren * Copyright (c) 1982, 1986, 1988, 1993
70 1.1 kefren * The Regents of the University of California. All rights reserved.
71 1.1 kefren *
72 1.1 kefren * Redistribution and use in source and binary forms, with or without
73 1.1 kefren * modification, are permitted provided that the following conditions
74 1.1 kefren * are met:
75 1.1 kefren * 1. Redistributions of source code must retain the above copyright
76 1.1 kefren * notice, this list of conditions and the following disclaimer.
77 1.1 kefren * 2. Redistributions in binary form must reproduce the above copyright
78 1.1 kefren * notice, this list of conditions and the following disclaimer in the
79 1.1 kefren * documentation and/or other materials provided with the distribution.
80 1.1 kefren * 3. Neither the name of the University nor the names of its contributors
81 1.1 kefren * may be used to endorse or promote products derived from this software
82 1.1 kefren * without specific prior written permission.
83 1.1 kefren *
84 1.1 kefren * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
85 1.1 kefren * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
86 1.1 kefren * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
87 1.1 kefren * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
88 1.1 kefren * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
89 1.1 kefren * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
90 1.1 kefren * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
91 1.1 kefren * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
92 1.1 kefren * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
93 1.1 kefren * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
94 1.1 kefren * SUCH DAMAGE.
95 1.1 kefren *
96 1.1 kefren * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
97 1.1 kefren */
98 1.1 kefren
99 1.1 kefren #include <sys/cdefs.h>
100 1.10 maxv __KERNEL_RCSID(0, "$NetBSD: mpls_ttl.c,v 1.10 2018/01/19 10:54:31 maxv Exp $");
101 1.1 kefren
102 1.5 pooka #ifdef _KERNEL_OPT
103 1.1 kefren #include "opt_inet.h"
104 1.1 kefren #include "opt_mpls.h"
105 1.5 pooka #endif
106 1.1 kefren
107 1.1 kefren #include <sys/param.h>
108 1.1 kefren #include <sys/malloc.h>
109 1.1 kefren #include <sys/mbuf.h>
110 1.1 kefren #include <sys/errno.h>
111 1.1 kefren #include <sys/socket.h>
112 1.1 kefren #include <sys/systm.h>
113 1.1 kefren
114 1.1 kefren #include <net/if.h>
115 1.1 kefren #include <net/if_dl.h>
116 1.1 kefren
117 1.1 kefren #include <netinet/in.h>
118 1.1 kefren #include <netinet/in_systm.h>
119 1.1 kefren #include <netinet/ip.h>
120 1.1 kefren #include <netinet/ip_icmp.h>
121 1.1 kefren #include <netinet/icmp_private.h>
122 1.1 kefren #include <netinet/icmp_var.h>
123 1.1 kefren
124 1.1 kefren #include <netmpls/mpls.h>
125 1.1 kefren #include <netmpls/mpls_var.h>
126 1.1 kefren
127 1.1 kefren #ifdef INET
128 1.1 kefren
129 1.1 kefren /* in netinet/ip_icmp.c */
130 1.1 kefren extern int icmpreturndatabytes;
131 1.1 kefren
132 1.1 kefren /* ICMP Extensions */
133 1.1 kefren #define MPLS_STACK_ENTRY_CLASS 1
134 1.1 kefren #define MPLS_STACK_ENTRY_C_TYPE 1
135 1.1 kefren
136 1.1 kefren struct mpls_extension {
137 1.10 maxv struct icmp_ext_hdr cmn_hdr;
138 1.1 kefren struct icmp_ext_obj_hdr obj_hdr;
139 1.1 kefren union mpls_shim ms;
140 1.1 kefren } __packed;
141 1.1 kefren
142 1.3 kefren static void mpls_icmp_error(struct mbuf *, int, int, n_long, int,
143 1.9 maxv union mpls_shim *);
144 1.9 maxv static struct mbuf *ip4_check(struct mbuf *);
145 1.1 kefren
146 1.1 kefren /*
147 1.10 maxv * Send an ICMP Extended error message. References: RFC4884 and RFC4950.
148 1.10 maxv *
149 1.1 kefren * This should be in sync with icmp_error() in sys/netinet/ip_icmp.c
150 1.4 kefren * XXX: is called only for ICMP_TIMXCEED_INTRANS but code is too general
151 1.1 kefren */
152 1.1 kefren static void
153 1.1 kefren mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest,
154 1.1 kefren int destmtu, union mpls_shim *shim)
155 1.1 kefren {
156 1.2 kefren struct ip *oip = mtod(n, struct ip *), *nip;
157 1.2 kefren unsigned oiplen = oip->ip_hl << 2;
158 1.2 kefren struct icmp *icp;
159 1.2 kefren struct mbuf *m;
160 1.2 kefren unsigned icmplen, mblen, packetlen;
161 1.1 kefren struct mpls_extension mpls_icmp_ext;
162 1.9 maxv
163 1.1 kefren memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext));
164 1.1 kefren mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION;
165 1.1 kefren mpls_icmp_ext.cmn_hdr.checksum = 0;
166 1.1 kefren
167 1.9 maxv mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) +
168 1.9 maxv sizeof(struct icmp_ext_obj_hdr));
169 1.1 kefren mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS;
170 1.1 kefren mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE;
171 1.1 kefren
172 1.1 kefren mpls_icmp_ext.ms.s_addr = shim->s_addr;
173 1.1 kefren
174 1.1 kefren #ifdef ICMPPRINTFS
175 1.1 kefren if (icmpprintfs)
176 1.1 kefren printf("mpls_icmp_error(%p, type:%d, code:%d)\n", oip, type,
177 1.1 kefren code);
178 1.1 kefren #endif
179 1.1 kefren if (type != ICMP_REDIRECT)
180 1.1 kefren ICMP_STATINC(ICMP_STAT_ERROR);
181 1.10 maxv
182 1.1 kefren /*
183 1.1 kefren * Don't send error if the original packet was encrypted.
184 1.1 kefren * Don't send error if not the first fragment of message.
185 1.1 kefren * Don't error if the old packet protocol was ICMP
186 1.1 kefren * error message, only known informational types.
187 1.1 kefren */
188 1.1 kefren if (n->m_flags & M_DECRYPTED)
189 1.1 kefren goto freeit;
190 1.1 kefren if (oip->ip_off &~ htons(IP_MF|IP_DF))
191 1.1 kefren goto freeit;
192 1.1 kefren if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
193 1.1 kefren n->m_len >= oiplen + ICMP_MINLEN &&
194 1.1 kefren !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type))
195 1.1 kefren {
196 1.1 kefren ICMP_STATINC(ICMP_STAT_OLDICMP);
197 1.1 kefren goto freeit;
198 1.1 kefren }
199 1.10 maxv
200 1.1 kefren /* Don't send error in response to a multicast or broadcast packet */
201 1.1 kefren if (n->m_flags & (M_BCAST|M_MCAST))
202 1.1 kefren goto freeit;
203 1.1 kefren
204 1.1 kefren /*
205 1.1 kefren * First, do a rate limitation check.
206 1.1 kefren */
207 1.1 kefren if (icmp_ratelimit(&oip->ip_src, type, code))
208 1.1 kefren /* XXX stats */
209 1.1 kefren goto freeit;
210 1.1 kefren
211 1.1 kefren /*
212 1.1 kefren * Now, formulate icmp message
213 1.1 kefren */
214 1.1 kefren icmplen = min(ICMP_EXT_OFFSET, ntohs(oip->ip_len));
215 1.10 maxv
216 1.1 kefren /*
217 1.1 kefren * Defend against mbuf chains shorter than oip->ip_len - oiplen:
218 1.1 kefren */
219 1.1 kefren mblen = 0;
220 1.1 kefren for (m = n; m && (mblen < icmplen); m = m->m_next)
221 1.1 kefren mblen += m->m_len;
222 1.1 kefren icmplen = min(mblen, icmplen);
223 1.1 kefren
224 1.4 kefren packetlen = sizeof(struct ip) + offsetof(struct icmp, icmp_ip) +
225 1.4 kefren ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext);
226 1.2 kefren
227 1.1 kefren /*
228 1.1 kefren * As we are not required to return everything we have,
229 1.1 kefren * we return whatever we can return at ease.
230 1.1 kefren *
231 1.1 kefren * Note that ICMP datagrams longer than 576 octets are out of spec
232 1.1 kefren * according to RFC1812; the limit on icmpreturndatabytes below in
233 1.1 kefren * icmp_sysctl will keep things below that limit.
234 1.1 kefren */
235 1.1 kefren
236 1.10 maxv KASSERT(packetlen <= MCLBYTES);
237 1.1 kefren
238 1.1 kefren m = m_gethdr(M_DONTWAIT, MT_HEADER);
239 1.2 kefren if (m && (packetlen > MHLEN)) {
240 1.1 kefren MCLGET(m, M_DONTWAIT);
241 1.1 kefren if ((m->m_flags & M_EXT) == 0) {
242 1.1 kefren m_freem(m);
243 1.1 kefren m = NULL;
244 1.1 kefren }
245 1.1 kefren }
246 1.1 kefren if (m == NULL)
247 1.1 kefren goto freeit;
248 1.10 maxv
249 1.1 kefren MCLAIM(m, n->m_owner);
250 1.2 kefren m->m_len = packetlen;
251 1.1 kefren if ((m->m_flags & M_EXT) == 0)
252 1.1 kefren MH_ALIGN(m, m->m_len);
253 1.4 kefren m->m_data += sizeof(struct ip);
254 1.4 kefren m->m_len -= sizeof(struct ip);
255 1.4 kefren
256 1.1 kefren icp = mtod(m, struct icmp *);
257 1.1 kefren if ((u_int)type > ICMP_MAXTYPE)
258 1.4 kefren panic("icmp error (mpls_ttl)");
259 1.1 kefren ICMP_STATINC(ICMP_STAT_OUTHIST + type);
260 1.1 kefren icp->icmp_type = type;
261 1.1 kefren if (type == ICMP_REDIRECT)
262 1.1 kefren icp->icmp_gwaddr.s_addr = dest;
263 1.1 kefren else {
264 1.1 kefren icp->icmp_void = 0;
265 1.1 kefren /*
266 1.1 kefren * The following assignments assume an overlay with the
267 1.1 kefren * zeroed icmp_void field.
268 1.1 kefren */
269 1.1 kefren if (type == ICMP_PARAMPROB) {
270 1.1 kefren icp->icmp_pptr = code;
271 1.1 kefren code = 0;
272 1.1 kefren } else if (type == ICMP_UNREACH &&
273 1.1 kefren code == ICMP_UNREACH_NEEDFRAG && destmtu)
274 1.1 kefren icp->icmp_nextmtu = htons(destmtu);
275 1.1 kefren }
276 1.1 kefren
277 1.1 kefren icp->icmp_code = code;
278 1.2 kefren
279 1.2 kefren memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET);
280 1.1 kefren m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip);
281 1.1 kefren
282 1.2 kefren /* Append the extension structure */
283 1.2 kefren memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET,
284 1.1 kefren &mpls_icmp_ext, sizeof(mpls_icmp_ext));
285 1.1 kefren
286 1.1 kefren /*
287 1.1 kefren * Now, copy old ip header (without options)
288 1.1 kefren * in front of icmp message.
289 1.9 maxv */
290 1.2 kefren if ((m->m_flags & M_EXT) == 0 &&
291 1.2 kefren m->m_data - sizeof(struct ip) < m->m_pktdat)
292 1.2 kefren panic("icmp len");
293 1.1 kefren m->m_data -= sizeof(struct ip);
294 1.1 kefren m->m_len += sizeof(struct ip);
295 1.1 kefren m->m_pkthdr.len = m->m_len;
296 1.8 ozaki m_copy_rcvif(m, n);
297 1.1 kefren nip = mtod(m, struct ip *);
298 1.1 kefren /* ip_v set in ip_output */
299 1.1 kefren nip->ip_hl = sizeof(struct ip) >> 2;
300 1.1 kefren nip->ip_tos = 0;
301 1.1 kefren nip->ip_len = htons(m->m_len);
302 1.1 kefren /* ip_id set in ip_output */
303 1.1 kefren nip->ip_off = htons(0);
304 1.1 kefren /* ip_ttl set in icmp_reflect */
305 1.1 kefren nip->ip_p = IPPROTO_ICMP;
306 1.1 kefren nip->ip_src = oip->ip_src;
307 1.1 kefren nip->ip_dst = oip->ip_dst;
308 1.1 kefren icmp_reflect(m);
309 1.1 kefren
310 1.1 kefren freeit:
311 1.1 kefren m_freem(n);
312 1.1 kefren }
313 1.1 kefren
314 1.9 maxv static struct mbuf *
315 1.3 kefren ip4_check(struct mbuf *m)
316 1.3 kefren {
317 1.3 kefren struct ip *iph;
318 1.3 kefren int hlen, len;
319 1.3 kefren
320 1.3 kefren if (m->m_len < sizeof(struct ip) &&
321 1.3 kefren (m = m_pullup(m, sizeof(struct ip))) == NULL)
322 1.9 maxv return NULL;
323 1.3 kefren
324 1.3 kefren iph = mtod(m, struct ip *);
325 1.3 kefren
326 1.3 kefren if (iph->ip_v != IPVERSION)
327 1.3 kefren goto freeit;
328 1.3 kefren hlen = iph->ip_hl << 2;
329 1.3 kefren if (hlen < sizeof(struct ip))
330 1.3 kefren goto freeit;
331 1.3 kefren if (hlen > m->m_len) {
332 1.3 kefren if ((m = m_pullup(m, hlen)) == NULL)
333 1.9 maxv return NULL;
334 1.3 kefren iph = mtod(m, struct ip *);
335 1.3 kefren }
336 1.10 maxv
337 1.10 maxv /*
338 1.10 maxv * RFC1122: packets with a multicast source address are
339 1.10 maxv * not allowed.
340 1.10 maxv * RFC1122: 127/8 must not appear on wire.
341 1.10 maxv */
342 1.3 kefren if (IN_MULTICAST(iph->ip_src.s_addr) ||
343 1.3 kefren (ntohl(iph->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
344 1.3 kefren (ntohl(iph->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
345 1.3 kefren in_cksum(m, hlen) != 0)
346 1.3 kefren goto freeit;
347 1.3 kefren
348 1.3 kefren len = ntohs(iph->ip_len);
349 1.3 kefren if (len < hlen || m->m_pkthdr.len < len)
350 1.3 kefren goto freeit;
351 1.3 kefren
352 1.9 maxv return m;
353 1.9 maxv
354 1.3 kefren freeit:
355 1.3 kefren m_freem(m);
356 1.9 maxv return NULL;
357 1.3 kefren }
358 1.1 kefren #endif /* INET */
359 1.1 kefren
360 1.1 kefren struct mbuf *
361 1.1 kefren mpls_ttl_dec(struct mbuf *m)
362 1.1 kefren {
363 1.1 kefren union mpls_shim *mshim;
364 1.1 kefren #ifdef INET
365 1.10 maxv union mpls_shim top_shim, bos_shim;
366 1.1 kefren #endif
367 1.1 kefren
368 1.4 kefren if (__predict_false(m->m_len < sizeof(union mpls_shim) &&
369 1.4 kefren (m = m_pullup(m, sizeof(union mpls_shim))) == NULL))
370 1.1 kefren return NULL;
371 1.1 kefren mshim = mtod(m, union mpls_shim *);
372 1.1 kefren mshim->s_addr = ntohl(mshim->s_addr);
373 1.1 kefren mshim->shim.ttl--;
374 1.1 kefren
375 1.1 kefren if (mshim->shim.ttl == 0) {
376 1.1 kefren if (!mpls_icmp_respond) {
377 1.1 kefren m_freem(m);
378 1.1 kefren return NULL;
379 1.1 kefren }
380 1.1 kefren
381 1.1 kefren #ifdef INET
382 1.1 kefren /*
383 1.9 maxv * Shim ttl exceeded. Send back ICMP type 11 code 0.
384 1.1 kefren */
385 1.10 maxv bos_shim.s_addr = mshim->s_addr;
386 1.2 kefren top_shim.s_addr = htonl(mshim->s_addr);
387 1.1 kefren m_adj(m, sizeof(union mpls_shim));
388 1.1 kefren
389 1.1 kefren /* Goto BOS */
390 1.10 maxv while (bos_shim.shim.bos == 0) {
391 1.1 kefren if (m->m_len < sizeof(union mpls_shim) &&
392 1.1 kefren (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) {
393 1.1 kefren m_freem(m);
394 1.1 kefren return NULL;
395 1.1 kefren }
396 1.10 maxv bos_shim.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr);
397 1.1 kefren m_adj(m, sizeof(union mpls_shim));
398 1.1 kefren }
399 1.9 maxv
400 1.9 maxv if ((m = ip4_check(m)) != NULL)
401 1.3 kefren mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
402 1.3 kefren 0, 0, &top_shim);
403 1.2 kefren #else
404 1.2 kefren m_freem(m);
405 1.1 kefren #endif
406 1.1 kefren return NULL;
407 1.1 kefren }
408 1.1 kefren
409 1.1 kefren mshim->s_addr = htonl(mshim->s_addr);
410 1.1 kefren
411 1.1 kefren return m;
412 1.1 kefren }
413