9pfs: fix crash when fsdev is missing
[qemu.git] / slirp / ip_icmp.c
1 /*
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
30 * ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
31 */
32
33 #include "qemu/osdep.h"
34 #include "slirp.h"
35 #include "ip_icmp.h"
36
37 /* The message sent when emulating PING */
38 /* Be nice and tell them it's just a pseudo-ping packet */
39 static const char icmp_ping_msg[] = "This is a pseudo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
40
41 /* list of actions for icmp_send_error() on RX of an icmp message */
42 static const int icmp_flush[19] = {
43 /* ECHO REPLY (0) */ 0,
44 1,
45 1,
46 /* DEST UNREACH (3) */ 1,
47 /* SOURCE QUENCH (4)*/ 1,
48 /* REDIRECT (5) */ 1,
49 1,
50 1,
51 /* ECHO (8) */ 0,
52 /* ROUTERADVERT (9) */ 1,
53 /* ROUTERSOLICIT (10) */ 1,
54 /* TIME EXCEEDED (11) */ 1,
55 /* PARAMETER PROBLEM (12) */ 1,
56 /* TIMESTAMP (13) */ 0,
57 /* TIMESTAMP REPLY (14) */ 0,
58 /* INFO (15) */ 0,
59 /* INFO REPLY (16) */ 0,
60 /* ADDR MASK (17) */ 0,
61 /* ADDR MASK REPLY (18) */ 0
62 };
63
64 void icmp_init(Slirp *slirp)
65 {
66 slirp->icmp.so_next = slirp->icmp.so_prev = &slirp->icmp;
67 slirp->icmp_last_so = &slirp->icmp;
68 }
69
70 void icmp_cleanup(Slirp *slirp)
71 {
72 while (slirp->icmp.so_next != &slirp->icmp) {
73 icmp_detach(slirp->icmp.so_next);
74 }
75 }
76
77 static int icmp_send(struct socket *so, struct mbuf *m, int hlen)
78 {
79 struct ip *ip = mtod(m, struct ip *);
80 struct sockaddr_in addr;
81
82 so->s = qemu_socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
83 if (so->s == -1) {
84 return -1;
85 }
86
87 so->so_m = m;
88 so->so_faddr = ip->ip_dst;
89 so->so_laddr = ip->ip_src;
90 so->so_iptos = ip->ip_tos;
91 so->so_type = IPPROTO_ICMP;
92 so->so_state = SS_ISFCONNECTED;
93 so->so_expire = curtime + SO_EXPIRE;
94
95 addr.sin_family = AF_INET;
96 addr.sin_addr = so->so_faddr;
97
98 insque(so, &so->slirp->icmp);
99
100 if (sendto(so->s, m->m_data + hlen, m->m_len - hlen, 0,
101 (struct sockaddr *)&addr, sizeof(addr)) == -1) {
102 DEBUG_MISC((dfd, "icmp_input icmp sendto tx errno = %d-%s\n",
103 errno, strerror(errno)));
104 icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
105 icmp_detach(so);
106 }
107
108 return 0;
109 }
110
111 void icmp_detach(struct socket *so)
112 {
113 closesocket(so->s);
114 sofree(so);
115 }
116
117 /*
118 * Process a received ICMP message.
119 */
120 void
121 icmp_input(struct mbuf *m, int hlen)
122 {
123 register struct icmp *icp;
124 register struct ip *ip=mtod(m, struct ip *);
125 int icmplen=ip->ip_len;
126 Slirp *slirp = m->slirp;
127
128 DEBUG_CALL("icmp_input");
129 DEBUG_ARG("m = %p", m);
130 DEBUG_ARG("m_len = %d", m->m_len);
131
132 /*
133 * Locate icmp structure in mbuf, and check
134 * that its not corrupted and of at least minimum length.
135 */
136 if (icmplen < ICMP_MINLEN) { /* min 8 bytes payload */
137 freeit:
138 m_free(m);
139 goto end_error;
140 }
141
142 m->m_len -= hlen;
143 m->m_data += hlen;
144 icp = mtod(m, struct icmp *);
145 if (cksum(m, icmplen)) {
146 goto freeit;
147 }
148 m->m_len += hlen;
149 m->m_data -= hlen;
150
151 DEBUG_ARG("icmp_type = %d", icp->icmp_type);
152 switch (icp->icmp_type) {
153 case ICMP_ECHO:
154 ip->ip_len += hlen; /* since ip_input subtracts this */
155 if (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
156 icmp_reflect(m);
157 } else if (slirp->restricted) {
158 goto freeit;
159 } else {
160 struct socket *so;
161 struct sockaddr_storage addr;
162 if ((so = socreate(slirp)) == NULL) goto freeit;
163 if (icmp_send(so, m, hlen) == 0) {
164 return;
165 }
166 if (udp_attach(so, AF_INET) == -1) {
167 DEBUG_MISC((dfd,"icmp_input udp_attach errno = %d-%s\n",
168 errno,strerror(errno)));
169 sofree(so);
170 m_free(m);
171 goto end_error;
172 }
173 so->so_m = m;
174 so->so_ffamily = AF_INET;
175 so->so_faddr = ip->ip_dst;
176 so->so_fport = htons(7);
177 so->so_lfamily = AF_INET;
178 so->so_laddr = ip->ip_src;
179 so->so_lport = htons(9);
180 so->so_iptos = ip->ip_tos;
181 so->so_type = IPPROTO_ICMP;
182 so->so_state = SS_ISFCONNECTED;
183
184 /* Send the packet */
185 addr = so->fhost.ss;
186 sotranslate_out(so, &addr);
187
188 if(sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0,
189 (struct sockaddr *)&addr, sockaddr_size(&addr)) == -1) {
190 DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
191 errno,strerror(errno)));
192 icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
193 udp_detach(so);
194 }
195 } /* if ip->ip_dst.s_addr == alias_addr.s_addr */
196 break;
197 case ICMP_UNREACH:
198 /* XXX? report error? close socket? */
199 case ICMP_TIMXCEED:
200 case ICMP_PARAMPROB:
201 case ICMP_SOURCEQUENCH:
202 case ICMP_TSTAMP:
203 case ICMP_MASKREQ:
204 case ICMP_REDIRECT:
205 m_free(m);
206 break;
207
208 default:
209 m_free(m);
210 } /* swith */
211
212 end_error:
213 /* m is m_free()'d xor put in a socket xor or given to ip_send */
214 return;
215 }
216
217
218 /*
219 * Send an ICMP message in response to a situation
220 *
221 * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
222 * MUST NOT change this header information.
223 * MUST NOT reply to a multicast/broadcast IP address.
224 * MUST NOT reply to a multicast/broadcast MAC address.
225 * MUST reply to only the first fragment.
226 */
227 /*
228 * Send ICMP_UNREACH back to the source regarding msrc.
229 * mbuf *msrc is used as a template, but is NOT m_free()'d.
230 * It is reported as the bad ip packet. The header should
231 * be fully correct and in host byte order.
232 * ICMP fragmentation is illegal. All machines must accept 576 bytes in one
233 * packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
234 */
235
236 #define ICMP_MAXDATALEN (IP_MSS-28)
237 void
238 icmp_send_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
239 const char *message)
240 {
241 unsigned hlen, shlen, s_ip_len;
242 register struct ip *ip;
243 register struct icmp *icp;
244 register struct mbuf *m;
245
246 DEBUG_CALL("icmp_send_error");
247 DEBUG_ARG("msrc = %p", msrc);
248 DEBUG_ARG("msrc_len = %d", msrc->m_len);
249
250 if(type!=ICMP_UNREACH && type!=ICMP_TIMXCEED) goto end_error;
251
252 /* check msrc */
253 if(!msrc) goto end_error;
254 ip = mtod(msrc, struct ip *);
255 #ifdef DEBUG
256 { char bufa[20], bufb[20];
257 strcpy(bufa, inet_ntoa(ip->ip_src));
258 strcpy(bufb, inet_ntoa(ip->ip_dst));
259 DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
260 }
261 #endif
262 if(ip->ip_off & IP_OFFMASK) goto end_error; /* Only reply to fragment 0 */
263
264 /* Do not reply to source-only IPs */
265 if ((ip->ip_src.s_addr & htonl(~(0xf << 28))) == 0) {
266 goto end_error;
267 }
268
269 shlen=ip->ip_hl << 2;
270 s_ip_len=ip->ip_len;
271 if(ip->ip_p == IPPROTO_ICMP) {
272 icp = (struct icmp *)((char *)ip + shlen);
273 /*
274 * Assume any unknown ICMP type is an error. This isn't
275 * specified by the RFC, but think about it..
276 */
277 if(icp->icmp_type>18 || icmp_flush[icp->icmp_type]) goto end_error;
278 }
279
280 /* make a copy */
281 m = m_get(msrc->slirp);
282 if (!m) {
283 goto end_error;
284 }
285
286 { int new_m_size;
287 new_m_size=sizeof(struct ip )+ICMP_MINLEN+msrc->m_len+ICMP_MAXDATALEN;
288 if(new_m_size>m->m_size) m_inc(m, new_m_size);
289 }
290 memcpy(m->m_data, msrc->m_data, msrc->m_len);
291 m->m_len = msrc->m_len; /* copy msrc to m */
292
293 /* make the header of the reply packet */
294 ip = mtod(m, struct ip *);
295 hlen= sizeof(struct ip ); /* no options in reply */
296
297 /* fill in icmp */
298 m->m_data += hlen;
299 m->m_len -= hlen;
300
301 icp = mtod(m, struct icmp *);
302
303 if(minsize) s_ip_len=shlen+ICMP_MINLEN; /* return header+8b only */
304 else if(s_ip_len>ICMP_MAXDATALEN) /* maximum size */
305 s_ip_len=ICMP_MAXDATALEN;
306
307 m->m_len=ICMP_MINLEN+s_ip_len; /* 8 bytes ICMP header */
308
309 /* min. size = 8+sizeof(struct ip)+8 */
310
311 icp->icmp_type = type;
312 icp->icmp_code = code;
313 icp->icmp_id = 0;
314 icp->icmp_seq = 0;
315
316 memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
317 HTONS(icp->icmp_ip.ip_len);
318 HTONS(icp->icmp_ip.ip_id);
319 HTONS(icp->icmp_ip.ip_off);
320
321 #ifdef DEBUG
322 if(message) { /* DEBUG : append message to ICMP packet */
323 int message_len;
324 char *cpnt;
325 message_len=strlen(message);
326 if(message_len>ICMP_MAXDATALEN) message_len=ICMP_MAXDATALEN;
327 cpnt=(char *)m->m_data+m->m_len;
328 memcpy(cpnt, message, message_len);
329 m->m_len+=message_len;
330 }
331 #endif
332
333 icp->icmp_cksum = 0;
334 icp->icmp_cksum = cksum(m, m->m_len);
335
336 m->m_data -= hlen;
337 m->m_len += hlen;
338
339 /* fill in ip */
340 ip->ip_hl = hlen >> 2;
341 ip->ip_len = m->m_len;
342
343 ip->ip_tos=((ip->ip_tos & 0x1E) | 0xC0); /* high priority for errors */
344
345 ip->ip_ttl = MAXTTL;
346 ip->ip_p = IPPROTO_ICMP;
347 ip->ip_dst = ip->ip_src; /* ip addresses */
348 ip->ip_src = m->slirp->vhost_addr;
349
350 (void ) ip_output((struct socket *)NULL, m);
351
352 end_error:
353 return;
354 }
355 #undef ICMP_MAXDATALEN
356
357 /*
358 * Reflect the ip packet back to the source
359 */
360 void
361 icmp_reflect(struct mbuf *m)
362 {
363 register struct ip *ip = mtod(m, struct ip *);
364 int hlen = ip->ip_hl << 2;
365 int optlen = hlen - sizeof(struct ip );
366 register struct icmp *icp;
367
368 /*
369 * Send an icmp packet back to the ip level,
370 * after supplying a checksum.
371 */
372 m->m_data += hlen;
373 m->m_len -= hlen;
374 icp = mtod(m, struct icmp *);
375
376 icp->icmp_type = ICMP_ECHOREPLY;
377 icp->icmp_cksum = 0;
378 icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
379
380 m->m_data -= hlen;
381 m->m_len += hlen;
382
383 /* fill in ip */
384 if (optlen > 0) {
385 /*
386 * Strip out original options by copying rest of first
387 * mbuf's data back, and adjust the IP length.
388 */
389 memmove((caddr_t)(ip + 1), (caddr_t)ip + hlen,
390 (unsigned )(m->m_len - hlen));
391 hlen -= optlen;
392 ip->ip_hl = hlen >> 2;
393 ip->ip_len -= optlen;
394 m->m_len -= optlen;
395 }
396
397 ip->ip_ttl = MAXTTL;
398 { /* swap */
399 struct in_addr icmp_dst;
400 icmp_dst = ip->ip_dst;
401 ip->ip_dst = ip->ip_src;
402 ip->ip_src = icmp_dst;
403 }
404
405 (void ) ip_output((struct socket *)NULL, m);
406 }
407
408 void icmp_receive(struct socket *so)
409 {
410 struct mbuf *m = so->so_m;
411 struct ip *ip = mtod(m, struct ip *);
412 int hlen = ip->ip_hl << 2;
413 u_char error_code;
414 struct icmp *icp;
415 int id, len;
416
417 m->m_data += hlen;
418 m->m_len -= hlen;
419 icp = mtod(m, struct icmp *);
420
421 id = icp->icmp_id;
422 len = qemu_recv(so->s, icp, m->m_len, 0);
423 icp->icmp_id = id;
424
425 m->m_data -= hlen;
426 m->m_len += hlen;
427
428 if (len == -1 || len == 0) {
429 if (errno == ENETUNREACH) {
430 error_code = ICMP_UNREACH_NET;
431 } else {
432 error_code = ICMP_UNREACH_HOST;
433 }
434 DEBUG_MISC((dfd, " udp icmp rx errno = %d-%s\n", errno,
435 strerror(errno)));
436 icmp_send_error(so->so_m, ICMP_UNREACH, error_code, 0, strerror(errno));
437 } else {
438 icmp_reflect(so->so_m);
439 so->so_m = NULL; /* Don't m_free() it again! */
440 }
441 icmp_detach(so);
442 }