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b688fc87 WJ |
1 | /* |
2 | * Copyright (c) 1982, 1986, 1989 Regents of the University of California. | |
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 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the University of | |
16 | * California, Berkeley and its contributors. | |
17 | * 4. Neither the name of the University nor the names of its contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | * | |
33 | * @(#)ip_icmp.c 7.15 (Berkeley) 4/20/91 | |
34 | */ | |
35 | ||
36 | #include "param.h" | |
37 | #include "systm.h" | |
38 | #include "malloc.h" | |
39 | #include "mbuf.h" | |
40 | #include "protosw.h" | |
41 | #include "socket.h" | |
42 | #include "time.h" | |
43 | #include "kernel.h" | |
44 | ||
45 | #include "../net/route.h" | |
46 | #include "../net/if.h" | |
47 | ||
48 | #include "in.h" | |
49 | #include "in_systm.h" | |
50 | #include "in_var.h" | |
51 | #include "ip.h" | |
52 | #include "ip_icmp.h" | |
53 | #include "icmp_var.h" | |
54 | ||
55 | /* | |
56 | * ICMP routines: error generation, receive packet processing, and | |
57 | * routines to turnaround packets back to the originator, and | |
58 | * host table maintenance routines. | |
59 | */ | |
60 | #ifdef ICMPPRINTFS | |
61 | int icmpprintfs = 0; | |
62 | #endif | |
63 | ||
64 | extern struct protosw inetsw[]; | |
65 | ||
66 | /* | |
67 | * Generate an error packet of type error | |
68 | * in response to bad packet ip. | |
69 | */ | |
70 | /*VARARGS3*/ | |
71 | icmp_error(n, type, code, dest) | |
72 | struct mbuf *n; | |
73 | int type, code; | |
74 | struct in_addr dest; | |
75 | { | |
76 | register struct ip *oip = mtod(n, struct ip *), *nip; | |
77 | register unsigned oiplen = oip->ip_hl << 2; | |
78 | register struct icmp *icp; | |
79 | register struct mbuf *m; | |
80 | unsigned icmplen; | |
81 | ||
82 | #ifdef ICMPPRINTFS | |
83 | if (icmpprintfs) | |
84 | printf("icmp_error(%x, %d, %d)\n", oip, type, code); | |
85 | #endif | |
86 | if (type != ICMP_REDIRECT) | |
87 | icmpstat.icps_error++; | |
88 | /* | |
89 | * Don't send error if not the first fragment of message. | |
90 | * Don't error if the old packet protocol was ICMP | |
91 | * error message, only known informational types. | |
92 | */ | |
93 | if (oip->ip_off &~ (IP_MF|IP_DF)) | |
94 | goto freeit; | |
95 | if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && | |
96 | n->m_len >= oiplen + ICMP_MINLEN && | |
97 | !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { | |
98 | icmpstat.icps_oldicmp++; | |
99 | goto freeit; | |
100 | } | |
101 | ||
102 | /* | |
103 | * First, formulate icmp message | |
104 | */ | |
105 | m = m_gethdr(M_DONTWAIT, MT_HEADER); | |
106 | if (m == NULL) | |
107 | goto freeit; | |
108 | icmplen = oiplen + min(8, oip->ip_len); | |
109 | m->m_len = icmplen + ICMP_MINLEN; | |
110 | MH_ALIGN(m, m->m_len); | |
111 | icp = mtod(m, struct icmp *); | |
112 | if ((u_int)type > ICMP_MAXTYPE) | |
113 | panic("icmp_error"); | |
114 | icmpstat.icps_outhist[type]++; | |
115 | icp->icmp_type = type; | |
116 | if (type == ICMP_REDIRECT) | |
117 | icp->icmp_gwaddr = dest; | |
118 | else | |
119 | icp->icmp_void = 0; | |
120 | if (type == ICMP_PARAMPROB) { | |
121 | icp->icmp_pptr = code; | |
122 | code = 0; | |
123 | } | |
124 | icp->icmp_code = code; | |
125 | bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen); | |
126 | nip = &icp->icmp_ip; | |
127 | nip->ip_len = htons((u_short)(nip->ip_len + oiplen)); | |
128 | ||
129 | /* | |
130 | * Now, copy old ip header (without options) | |
131 | * in front of icmp message. | |
132 | */ | |
133 | if (m->m_data - sizeof(struct ip) < m->m_pktdat) | |
134 | panic("icmp len"); | |
135 | m->m_data -= sizeof(struct ip); | |
136 | m->m_len += sizeof(struct ip); | |
137 | m->m_pkthdr.len = m->m_len; | |
138 | m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; | |
139 | nip = mtod(m, struct ip *); | |
140 | bcopy((caddr_t)oip, (caddr_t)nip, oiplen); | |
141 | nip->ip_len = m->m_len; | |
142 | nip->ip_hl = sizeof(struct ip) >> 2; | |
143 | nip->ip_p = IPPROTO_ICMP; | |
144 | icmp_reflect(m); | |
145 | ||
146 | freeit: | |
147 | m_freem(n); | |
148 | } | |
149 | ||
150 | static struct sockproto icmproto = { AF_INET, IPPROTO_ICMP }; | |
151 | static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET }; | |
152 | static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET }; | |
153 | static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET }; | |
154 | struct sockaddr_in icmpmask = { 8, 0 }; | |
155 | struct in_ifaddr *ifptoia(); | |
156 | ||
157 | /* | |
158 | * Process a received ICMP message. | |
159 | */ | |
160 | icmp_input(m, hlen) | |
161 | register struct mbuf *m; | |
162 | int hlen; | |
163 | { | |
164 | register struct icmp *icp; | |
165 | register struct ip *ip = mtod(m, struct ip *); | |
166 | int icmplen = ip->ip_len; | |
167 | register int i; | |
168 | struct in_ifaddr *ia; | |
169 | int (*ctlfunc)(), code; | |
170 | extern u_char ip_protox[]; | |
171 | extern struct in_addr in_makeaddr(); | |
172 | ||
173 | /* | |
174 | * Locate icmp structure in mbuf, and check | |
175 | * that not corrupted and of at least minimum length. | |
176 | */ | |
177 | #ifdef ICMPPRINTFS | |
178 | if (icmpprintfs) | |
179 | printf("icmp_input from %x, len %d\n", ip->ip_src, icmplen); | |
180 | #endif | |
181 | if (icmplen < ICMP_MINLEN) { | |
182 | icmpstat.icps_tooshort++; | |
183 | goto freeit; | |
184 | } | |
185 | i = hlen + MIN(icmplen, ICMP_ADVLENMIN); | |
186 | if (m->m_len < i && (m = m_pullup(m, i)) == 0) { | |
187 | icmpstat.icps_tooshort++; | |
188 | return; | |
189 | } | |
190 | ip = mtod(m, struct ip *); | |
191 | m->m_len -= hlen; | |
192 | m->m_data += hlen; | |
193 | icp = mtod(m, struct icmp *); | |
194 | if (in_cksum(m, icmplen)) { | |
195 | icmpstat.icps_checksum++; | |
196 | goto freeit; | |
197 | } | |
198 | m->m_len += hlen; | |
199 | m->m_data -= hlen; | |
200 | ||
201 | #ifdef ICMPPRINTFS | |
202 | /* | |
203 | * Message type specific processing. | |
204 | */ | |
205 | if (icmpprintfs) | |
206 | printf("icmp_input, type %d code %d\n", icp->icmp_type, | |
207 | icp->icmp_code); | |
208 | #endif | |
209 | if (icp->icmp_type > ICMP_MAXTYPE) | |
210 | goto raw; | |
211 | icmpstat.icps_inhist[icp->icmp_type]++; | |
212 | code = icp->icmp_code; | |
213 | switch (icp->icmp_type) { | |
214 | ||
215 | case ICMP_UNREACH: | |
216 | if (code > 5) | |
217 | goto badcode; | |
218 | code += PRC_UNREACH_NET; | |
219 | goto deliver; | |
220 | ||
221 | case ICMP_TIMXCEED: | |
222 | if (code > 1) | |
223 | goto badcode; | |
224 | code += PRC_TIMXCEED_INTRANS; | |
225 | goto deliver; | |
226 | ||
227 | case ICMP_PARAMPROB: | |
228 | if (code) | |
229 | goto badcode; | |
230 | code = PRC_PARAMPROB; | |
231 | goto deliver; | |
232 | ||
233 | case ICMP_SOURCEQUENCH: | |
234 | if (code) | |
235 | goto badcode; | |
236 | code = PRC_QUENCH; | |
237 | deliver: | |
238 | /* | |
239 | * Problem with datagram; advise higher level routines. | |
240 | */ | |
241 | if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || | |
242 | icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { | |
243 | icmpstat.icps_badlen++; | |
244 | goto freeit; | |
245 | } | |
246 | NTOHS(icp->icmp_ip.ip_len); | |
247 | #ifdef ICMPPRINTFS | |
248 | if (icmpprintfs) | |
249 | printf("deliver to protocol %d\n", icp->icmp_ip.ip_p); | |
250 | #endif | |
251 | icmpsrc.sin_addr = icp->icmp_ip.ip_dst; | |
252 | if (ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput) | |
253 | (*ctlfunc)(code, (struct sockaddr *)&icmpsrc, | |
254 | (caddr_t) &icp->icmp_ip); | |
255 | break; | |
256 | ||
257 | badcode: | |
258 | icmpstat.icps_badcode++; | |
259 | break; | |
260 | ||
261 | case ICMP_ECHO: | |
262 | icp->icmp_type = ICMP_ECHOREPLY; | |
263 | goto reflect; | |
264 | ||
265 | case ICMP_TSTAMP: | |
266 | if (icmplen < ICMP_TSLEN) { | |
267 | icmpstat.icps_badlen++; | |
268 | break; | |
269 | } | |
270 | icp->icmp_type = ICMP_TSTAMPREPLY; | |
271 | icp->icmp_rtime = iptime(); | |
272 | icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ | |
273 | goto reflect; | |
274 | ||
275 | case ICMP_IREQ: | |
276 | #define satosin(sa) ((struct sockaddr_in *)(sa)) | |
277 | if (in_netof(ip->ip_src) == 0 && | |
278 | (ia = ifptoia(m->m_pkthdr.rcvif))) | |
279 | ip->ip_src = in_makeaddr(in_netof(IA_SIN(ia)->sin_addr), | |
280 | in_lnaof(ip->ip_src)); | |
281 | icp->icmp_type = ICMP_IREQREPLY; | |
282 | goto reflect; | |
283 | ||
284 | case ICMP_MASKREQ: | |
285 | if (icmplen < ICMP_MASKLEN || | |
286 | (ia = ifptoia(m->m_pkthdr.rcvif)) == 0) | |
287 | break; | |
288 | icp->icmp_type = ICMP_MASKREPLY; | |
289 | icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; | |
290 | if (ip->ip_src.s_addr == 0) { | |
291 | if (ia->ia_ifp->if_flags & IFF_BROADCAST) | |
292 | ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; | |
293 | else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) | |
294 | ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; | |
295 | } | |
296 | reflect: | |
297 | ip->ip_len += hlen; /* since ip_input deducts this */ | |
298 | icmpstat.icps_reflect++; | |
299 | icmpstat.icps_outhist[icp->icmp_type]++; | |
300 | icmp_reflect(m); | |
301 | return; | |
302 | ||
303 | case ICMP_REDIRECT: | |
304 | if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) { | |
305 | icmpstat.icps_badlen++; | |
306 | break; | |
307 | } | |
308 | /* | |
309 | * Short circuit routing redirects to force | |
310 | * immediate change in the kernel's routing | |
311 | * tables. The message is also handed to anyone | |
312 | * listening on a raw socket (e.g. the routing | |
313 | * daemon for use in updating its tables). | |
314 | */ | |
315 | icmpgw.sin_addr = ip->ip_src; | |
316 | icmpdst.sin_addr = icp->icmp_gwaddr; | |
317 | #ifdef ICMPPRINTFS | |
318 | if (icmpprintfs) | |
319 | printf("redirect dst %x to %x\n", icp->icmp_ip.ip_dst, | |
320 | icp->icmp_gwaddr); | |
321 | #endif | |
322 | if (code == ICMP_REDIRECT_NET || code == ICMP_REDIRECT_TOSNET) { | |
323 | u_long in_netof(); | |
324 | icmpsrc.sin_addr = | |
325 | in_makeaddr(in_netof(icp->icmp_ip.ip_dst), INADDR_ANY); | |
326 | in_sockmaskof(icp->icmp_ip.ip_dst, &icmpmask); | |
327 | rtredirect((struct sockaddr *)&icmpsrc, | |
328 | (struct sockaddr *)&icmpdst, | |
329 | (struct sockaddr *)&icmpmask, RTF_GATEWAY, | |
330 | (struct sockaddr *)&icmpgw, (struct rtentry **)0); | |
331 | icmpsrc.sin_addr = icp->icmp_ip.ip_dst; | |
332 | pfctlinput(PRC_REDIRECT_NET, | |
333 | (struct sockaddr *)&icmpsrc); | |
334 | } else { | |
335 | icmpsrc.sin_addr = icp->icmp_ip.ip_dst; | |
336 | rtredirect((struct sockaddr *)&icmpsrc, | |
337 | (struct sockaddr *)&icmpdst, | |
338 | (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST, | |
339 | (struct sockaddr *)&icmpgw, (struct rtentry **)0); | |
340 | pfctlinput(PRC_REDIRECT_HOST, | |
341 | (struct sockaddr *)&icmpsrc); | |
342 | } | |
343 | break; | |
344 | ||
345 | /* | |
346 | * No kernel processing for the following; | |
347 | * just fall through to send to raw listener. | |
348 | */ | |
349 | case ICMP_ECHOREPLY: | |
350 | case ICMP_TSTAMPREPLY: | |
351 | case ICMP_IREQREPLY: | |
352 | case ICMP_MASKREPLY: | |
353 | default: | |
354 | break; | |
355 | } | |
356 | ||
357 | raw: | |
358 | icmpsrc.sin_addr = ip->ip_src; | |
359 | icmpdst.sin_addr = ip->ip_dst; | |
360 | (void) raw_input(m, &icmproto, (struct sockaddr *)&icmpsrc, | |
361 | (struct sockaddr *)&icmpdst); | |
362 | return; | |
363 | ||
364 | freeit: | |
365 | m_freem(m); | |
366 | } | |
367 | ||
368 | /* | |
369 | * Reflect the ip packet back to the source | |
370 | */ | |
371 | icmp_reflect(m) | |
372 | struct mbuf *m; | |
373 | { | |
374 | register struct ip *ip = mtod(m, struct ip *); | |
375 | register struct in_ifaddr *ia; | |
376 | struct in_addr t; | |
377 | struct mbuf *opts = 0, *ip_srcroute(); | |
378 | int optlen = (ip->ip_hl << 2) - sizeof(struct ip); | |
379 | ||
380 | t = ip->ip_dst; | |
381 | ip->ip_dst = ip->ip_src; | |
382 | /* | |
383 | * If the incoming packet was addressed directly to us, | |
384 | * use dst as the src for the reply. Otherwise (broadcast | |
385 | * or anonymous), use the address which corresponds | |
386 | * to the incoming interface. | |
387 | */ | |
388 | for (ia = in_ifaddr; ia; ia = ia->ia_next) { | |
389 | if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) | |
390 | break; | |
391 | if ((ia->ia_ifp->if_flags & IFF_BROADCAST) && | |
392 | t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr) | |
393 | break; | |
394 | } | |
395 | if (ia == (struct in_ifaddr *)0) | |
396 | ia = ifptoia(m->m_pkthdr.rcvif); | |
397 | if (ia == (struct in_ifaddr *)0) | |
398 | ia = in_ifaddr; | |
399 | t = IA_SIN(ia)->sin_addr; | |
400 | ip->ip_src = t; | |
401 | ip->ip_ttl = MAXTTL; | |
402 | ||
403 | if (optlen > 0) { | |
404 | register u_char *cp; | |
405 | int opt, cnt; | |
406 | u_int len; | |
407 | ||
408 | /* | |
409 | * Retrieve any source routing from the incoming packet; | |
410 | * add on any record-route or timestamp options. | |
411 | */ | |
412 | cp = (u_char *) (ip + 1); | |
413 | if ((opts = ip_srcroute()) == 0 && | |
414 | (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { | |
415 | opts->m_len = sizeof(struct in_addr); | |
416 | mtod(opts, struct in_addr *)->s_addr = 0; | |
417 | } | |
418 | if (opts) { | |
419 | #ifdef ICMPPRINTFS | |
420 | if (icmpprintfs) | |
421 | printf("icmp_reflect optlen %d rt %d => ", | |
422 | optlen, opts->m_len); | |
423 | #endif | |
424 | for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { | |
425 | opt = cp[IPOPT_OPTVAL]; | |
426 | if (opt == IPOPT_EOL) | |
427 | break; | |
428 | if (opt == IPOPT_NOP) | |
429 | len = 1; | |
430 | else { | |
431 | len = cp[IPOPT_OLEN]; | |
432 | if (len <= 0 || len > cnt) | |
433 | break; | |
434 | } | |
435 | /* | |
436 | * should check for overflow, but it "can't happen" | |
437 | */ | |
438 | if (opt == IPOPT_RR || opt == IPOPT_TS) { | |
439 | bcopy((caddr_t)cp, | |
440 | mtod(opts, caddr_t) + opts->m_len, len); | |
441 | opts->m_len += len; | |
442 | } | |
443 | } | |
444 | if (opts->m_len % 4 != 0) { | |
445 | *(mtod(opts, caddr_t) + opts->m_len) = IPOPT_EOL; | |
446 | opts->m_len++; | |
447 | } | |
448 | #ifdef ICMPPRINTFS | |
449 | if (icmpprintfs) | |
450 | printf("%d\n", opts->m_len); | |
451 | #endif | |
452 | } | |
453 | /* | |
454 | * Now strip out original options by copying rest of first | |
455 | * mbuf's data back, and adjust the IP length. | |
456 | */ | |
457 | ip->ip_len -= optlen; | |
458 | ip->ip_hl = sizeof(struct ip) >> 2; | |
459 | m->m_len -= optlen; | |
460 | if (m->m_flags & M_PKTHDR) | |
461 | m->m_pkthdr.len -= optlen; | |
462 | optlen += sizeof(struct ip); | |
463 | bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1), | |
464 | (unsigned)(m->m_len - sizeof(struct ip))); | |
465 | } | |
466 | icmp_send(m, opts); | |
467 | if (opts) | |
468 | (void)m_free(opts); | |
469 | } | |
470 | ||
471 | struct in_ifaddr * | |
472 | ifptoia(ifp) | |
473 | struct ifnet *ifp; | |
474 | { | |
475 | register struct in_ifaddr *ia; | |
476 | ||
477 | for (ia = in_ifaddr; ia; ia = ia->ia_next) | |
478 | if (ia->ia_ifp == ifp) | |
479 | return (ia); | |
480 | return ((struct in_ifaddr *)0); | |
481 | } | |
482 | ||
483 | /* | |
484 | * Send an icmp packet back to the ip level, | |
485 | * after supplying a checksum. | |
486 | */ | |
487 | icmp_send(m, opts) | |
488 | register struct mbuf *m; | |
489 | struct mbuf *opts; | |
490 | { | |
491 | register struct ip *ip = mtod(m, struct ip *); | |
492 | register int hlen; | |
493 | register struct icmp *icp; | |
494 | ||
495 | hlen = ip->ip_hl << 2; | |
496 | m->m_data += hlen; | |
497 | m->m_len -= hlen; | |
498 | icp = mtod(m, struct icmp *); | |
499 | icp->icmp_cksum = 0; | |
500 | icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen); | |
501 | m->m_data -= hlen; | |
502 | m->m_len += hlen; | |
503 | #ifdef ICMPPRINTFS | |
504 | if (icmpprintfs) | |
505 | printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src); | |
506 | #endif | |
507 | (void) ip_output(m, opts, (struct route *)0, 0); | |
508 | } | |
509 | ||
510 | n_time | |
511 | iptime() | |
512 | { | |
513 | struct timeval atv; | |
514 | u_long t; | |
515 | ||
516 | microtime(&atv); | |
517 | t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; | |
518 | return (htonl(t)); | |
519 | } |