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