ip_icmp.c@ 20703

Last change on this file since 20703 was 20257, checked in by vboxsync, 16 years ago
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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. 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 8.2 (Berkeley) 1/4/94
34	* ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
35	*/
36
37	#include "slirp.h"
38	#include "ip_icmp.h"
39	#ifdef RT_OS_WINDOWS
40	#include <Icmpapi.h>
41	#include <Iphlpapi.h>
42	#endif
43
44	#ifdef RT_OS_WINDOWS
45	# define ICMP_SEND_ECHO(event, routine, addr, data, datasize, ipopt) \
46	IcmpSendEcho2(pData->icmp_socket.sh, (event), NULL, NULL, (addr), (data), (datasize), \
47	(ipopt), pData->pvIcmpBuffer, pData->szIcmpBuffer, 1)
48	#endif /* RT_OS_WINDOWS */
49
50	/* The message sent when emulating PING */
51	/* Be nice and tell them it's just a psuedo-ping packet */
52	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
53
54	/* list of actions for icmp_error() on RX of an icmp message */
55	static const int icmp_flush[19] =
56	{
57	/* ECHO REPLY (0) */ 0,
58	1,
59	1,
60	/* DEST UNREACH (3) */ 1,
61	/* SOURCE QUENCH (4)*/ 1,
62	/* REDIRECT (5) */ 1,
63	1,
64	1,
65	/* ECHO (8) */ 0,
66	/* ROUTERADVERT (9) */ 1,
67	/* ROUTERSOLICIT (10) */ 1,
68	/* TIME EXCEEDED (11) */ 1,
69	/* PARAMETER PROBLEM (12) */ 1,
70	/* TIMESTAMP (13) */ 0,
71	/* TIMESTAMP REPLY (14) */ 0,
72	/* INFO (15) */ 0,
73	/* INFO REPLY (16) */ 0,
74	/* ADDR MASK (17) */ 0,
75	/* ADDR MASK REPLY (18) */ 0
76	};
77
78	int
79	icmp_init(PNATState pData)
80	{
81	pData->icmp_socket.so_type = IPPROTO_ICMP;
82	pData->icmp_socket.so_state = SS_ISFCONNECTED;
83	#ifndef RT_OS_WINDOWS
84	# ifndef RT_OS_DARWIN
85	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
86	# else /* !RT_OS_DARWIN */
87	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
88	# endif /* RT_OS_DARWIN */
89	if (pData->icmp_socket.s == -1)
90	{
91	int rc = RTErrConvertFromErrno(errno);
92	LogRel(("NAT: ICMP/ping not available (could open ICMP socket, error %Rrc)\n", rc));
93	return 1;
94	}
95	fd_nonblock(pData->icmp_socket.s);
96	NSOCK_INC();
97	#else /* RT_OS_WINDOWS */
98	pData->hmIcmpLibrary = LoadLibrary("Iphlpapi.dll");
99	if (pData->hmIcmpLibrary != NULL)
100	{
101	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
102	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
103	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
104	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
105	# ifdef VBOX_WITH_MULTI_DNS
106	pData->pfGetAdaptersAddresses = (ULONG (WINAPI *)(ULONG, ULONG, PVOID, PIP_ADAPTER_ADDRESSES, PULONG))
107	GetProcAddress(pData->hmIcmpLibrary, "GetAdaptersAddresses");
108	if (pData->pfGetAdaptersAddresses == NULL)
109	{
110	LogRel(("NAT: Can't find GetAdapterAddresses in Iphlpapi.dll"));
111	}
112	# endif
113	}
114
115	if (pData->pfIcmpParseReplies == NULL)
116	{
117	# ifdef VBOX_WITH_MULTI_DNS
118	if(pData->pfGetAdaptersAddresses == NULL)
119	FreeLibrary(pData->hmIcmpLibrary);
120	# else
121	FreeLibrary(pData->hmIcmpLibrary);
122	# endif
123	pData->hmIcmpLibrary = LoadLibrary("Icmp.dll");
124	if (pData->hmIcmpLibrary == NULL)
125	{
126	LogRel(("NAT: Icmp.dll could not be loaded\n"));
127	return 1;
128	}
129	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
130	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
131	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
132	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
133	}
134	if (pData->pfIcmpParseReplies == NULL)
135	{
136	LogRel(("NAT: Can't find IcmpParseReplies symbol\n"));
137	FreeLibrary(pData->hmIcmpLibrary);
138	return 1;
139	}
140	if (pData->pfIcmpCloseHandle == NULL)
141	{
142	LogRel(("NAT: Can't find IcmpCloseHandle symbol\n"));
143	FreeLibrary(pData->hmIcmpLibrary);
144	return 1;
145	}
146	pData->icmp_socket.sh = IcmpCreateFile();
147	pData->phEvents[VBOX_ICMP_EVENT_INDEX] = CreateEvent(NULL, FALSE, FALSE, NULL);
148	pData->szIcmpBuffer = sizeof(ICMP_ECHO_REPLY) * 10;
149	pData->pvIcmpBuffer = RTMemAlloc(pData->szIcmpBuffer);
150	#endif /* RT_OS_WINDOWS */
151	LIST_INIT(&pData->icmp_msg_head);
152	return 0;
153	}
154
155	/*
156	* ip here is ip header + 64bytes readed from ICMP packet
157	*/
158	struct icmp_msg *
159	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
160	{
161	struct mbuf *m0;
162	struct ip *ip0;
163	struct icmp icp, icp0;
164	struct icmp_msg *icm = NULL;
165	int found = 0;
166	struct udphdr *udp;
167	struct tcphdr *tcp;
168	struct socket *head_socket = NULL;
169	struct socket *last_socket = NULL;
170	struct socket *so = NULL;
171	struct in_addr laddr, faddr;
172	u_short lport, fport;
173
174	laddr.s_addr = ~0;
175	faddr.s_addr = ~0;
176
177	lport = ~0;
178	fport = ~0;
179
180
181	Log(("%s: processing (proto:%d)\n", __FUNCTION__, ip->ip_p));
182	switch (ip->ip_p)
183	{
184	case IPPROTO_ICMP:
185	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
186	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
187	{
188	m0 = icm->im_m;
189	ip0 = mtod(m0, struct ip *);
190	AssertRelease(ip0->ip_p == IPPROTO_ICMP);
191	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
192	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
193	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
194	&& icp->icmp_id == icp0->icmp_id
195	&& icp->icmp_seq == icp0->icmp_seq)
196	{
197	found = 1;
198	Log(("Have found %R[natsock]\n", icm->im_so));
199	break;
200	}
201	Log(("Have found nothing\n"));
202	}
203	break;
204
205	/*
206	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
207	* from which the IP package has been sent.
208	*/
209	case IPPROTO_UDP:
210	head_socket = &udb;
211	udp = (struct udphdr )((char )ip + (ip->ip_hl << 2));
212	faddr.s_addr = ip->ip_dst.s_addr;
213	fport = udp->uh_dport;
214	laddr.s_addr = ip->ip_src.s_addr;
215	lport = udp->uh_sport;
216	last_socket = udp_last_so;
217	/* fall through */
218
219	case IPPROTO_TCP:
220	if (head_socket == NULL)
221	{
222	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
223	head_socket = &tcb; /* head_socket could be initialized with udb*/
224	faddr.s_addr = ip->ip_dst.s_addr;
225	fport = tcp->th_dport;
226	laddr.s_addr = ip->ip_src.s_addr;
227	lport = tcp->th_sport;
228	last_socket = tcp_last_so;
229	}
230	/* check last socket first */
231	if ( last_socket->so_faddr.s_addr == faddr.s_addr
232	&& last_socket->so_fport == fport
233	&& last_socket->so_hlport == lport)
234	{
235	found = 1;
236	so = last_socket;
237	goto sofound;
238	}
239	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
240	{
241	/* Should be reaplaced by hash here */
242	Log(("trying:%R[natsock] against %R[IP4]:%d lport=%d hlport=%d\n", so, &faddr, fport, lport, so->so_hlport));
243	if ( so->so_faddr.s_addr == faddr.s_addr
244	&& so->so_fport == fport
245	&& so->so_hlport == lport)
246	{
247	found = 1;
248	break;
249	}
250	}
251	break;
252
253	default:
254	LogRel(("%s:ICMP: unsupported protocol(%d)\n", __FUNCTION__, ip->ip_p));
255	}
256	sofound:
257	if (found == 1 && icm == NULL)
258	{
259	if (so->so_state == SS_NOFDREF)
260	{
261	/* socket is shutdowning we've already sent ICMP on it.*/
262	LogRel(("NAT: Received icmp on shutdowning socket (probably corresponding ICMP socket has been already sent)\n"));
263	return NULL;
264	}
265	icm = RTMemAlloc(sizeof(struct icmp_msg));
266	icm->im_m = so->so_m;
267	icm->im_so = so;
268	found = 1;
269	Log(("hit:%R[natsock]\n", so));
270	/*XXX: this storage not very long,
271	* better add flag if it should removed from lis
272	*/
273	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
274	return (icm);
275	}
276	if (found == 1)
277	return icm;
278
279	return NULL;
280	}
281
282	static int
283	icmp_attach(PNATState pData, struct mbuf *m)
284	{
285	struct icmp_msg *icm;
286	struct ip *ip;
287	ip = mtod(m, struct ip *);
288	Assert(ip->ip_p == IPPROTO_ICMP);
289	icm = RTMemAlloc(sizeof(struct icmp_msg));
290	icm->im_m = m;
291	icm->im_so = m->m_so;
292	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
293	return 0;
294	}
295
296	/*
297	* Process a received ICMP message.
298	*/
299	void
300	icmp_input(PNATState pData, struct mbuf *m, int hlen)
301	{
302	register struct icmp *icp;
303	register struct ip ip = mtod(m, struct ip );
304	int icmplen = ip->ip_len;
305	int status;
306	uint32_t dst;
307	#if !defined(RT_OS_WINDOWS)
308	int ttl;
309	#endif
310
311	/* int code; */
312
313	DEBUG_CALL("icmp_input");
314	DEBUG_ARG("m = %lx", (long )m);
315	DEBUG_ARG("m_len = %d", m->m_len);
316
317	icmpstat.icps_received++;
318
319	/*
320	* Locate icmp structure in mbuf, and check
321	* that its not corrupted and of at least minimum length.
322	*/
323	if (icmplen < ICMP_MINLEN)
324	{
325	/* min 8 bytes payload */
326	icmpstat.icps_tooshort++;
327	freeit:
328	m_freem(pData, m);
329	goto end_error;
330	}
331
332	m->m_len -= hlen;
333	m->m_data += hlen;
334	icp = mtod(m, struct icmp *);
335	if (cksum(m, icmplen))
336	{
337	icmpstat.icps_checksum++;
338	goto freeit;
339	}
340	m->m_len += hlen;
341	m->m_data -= hlen;
342
343	/* icmpstat.icps_inhist[icp->icmp_type]++; */
344	/* code = icp->icmp_code; */
345
346	DEBUG_ARG("icmp_type = %d", icp->icmp_type);
347	switch (icp->icmp_type)
348	{
349	case ICMP_ECHO:
350	ip->ip_len += hlen; /* since ip_input subtracts this */
351	dst = ip->ip_dst.s_addr;
352	if (dst == alias_addr.s_addr)
353	{
354	icp->icmp_type = ICMP_ECHOREPLY;
355	ip->ip_dst.s_addr = ip->ip_src.s_addr;
356	ip->ip_src.s_addr = dst;
357	icmp_reflect(pData, m);
358	}
359	else
360	{
361	struct sockaddr_in addr;
362	#ifdef RT_OS_WINDOWS
363	IP_OPTION_INFORMATION ipopt;
364	int error;
365	#endif
366	addr.sin_family = AF_INET;
367	if ((ip->ip_dst.s_addr & htonl(pData->netmask)) == special_addr.s_addr)
368	{
369	/* It's an alias */
370	switch (ntohl(ip->ip_dst.s_addr) & ~pData->netmask)
371	{
372	case CTL_DNS:
373	#ifndef VBOX_WITH_MULTI_DNS
374	addr.sin_addr = dns_addr;
375	break;
376	#endif
377	case CTL_ALIAS:
378	default:
379	addr.sin_addr = loopback_addr;
380	break;
381	}
382	}
383	else
384	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
385	#ifndef RT_OS_WINDOWS
386	if (pData->icmp_socket.s != -1)
387	{
388	m->m_so = &pData->icmp_socket;
389	icmp_attach(pData, m);
390	ttl = ip->ip_ttl;
391	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
392	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
393	(void *)&ttl, sizeof(ttl));
394	if (status < 0)
395	LogRel(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
396	strerror(errno)));
397	if (sendto(pData->icmp_socket.s, icp, icmplen, 0,
398	(struct sockaddr *)&addr, sizeof(addr)) == -1)
399	{
400	Log((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
401	errno, strerror(errno)));
402	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
403	}
404	}
405	else
406	{
407	/*
408	* We're freeing the ICMP message, which unable sent or process.
409	* That behavior described in rfc 793, we shouldn't notify sender about
410	* fail of processing it's ICMP packets
411	*/
412	m_free(pData, m);
413	return;
414	}
415	#else /* RT_OS_WINDOWS */
416	icmp_attach(pData, m);
417	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
418	pData->icmp_socket.so_icmp_id = icp->icmp_id;
419	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
420	m->m_so = &pData->icmp_socket;
421	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
422	ipopt.Ttl = ip->ip_ttl;
423	status = ICMP_SEND_ECHO(pData->phEvents[VBOX_ICMP_EVENT_INDEX], notify_slirp, addr.sin_addr.s_addr,
424	icp->icmp_data, icmplen - ICMP_MINLEN, &ipopt);
425	if (status == 0 && (error = GetLastError()) != ERROR_IO_PENDING)
426	{
427	error = GetLastError();
428	LogRel(("NAT: Error (%d) occurred while sending ICMP (", error));
429	switch (error)
430	{
431	case ERROR_INVALID_PARAMETER:
432	LogRel(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
433	break;
434	case ERROR_NOT_SUPPORTED:
435	LogRel(("operation is unsupported)\n"));
436	break;
437	case ERROR_NOT_ENOUGH_MEMORY:
438	LogRel(("OOM!!!)\n"));
439	break;
440	case IP_BUF_TOO_SMALL:
441	LogRel(("Buffer too small)\n"));
442	break;
443	default:
444	LogRel(("Other error!!!)\n"));
445	break;
446	}
447	}
448	#endif /* RT_OS_WINDOWS */
449	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
450	break;
451	case ICMP_UNREACH:
452	/* XXX? report error? close socket? */
453	case ICMP_TIMXCEED:
454	case ICMP_PARAMPROB:
455	case ICMP_SOURCEQUENCH:
456	case ICMP_TSTAMP:
457	case ICMP_MASKREQ:
458	case ICMP_REDIRECT:
459	icmpstat.icps_notsupp++;
460	m_freem(pData, m);
461	break;
462
463	default:
464	icmpstat.icps_badtype++;
465	m_freem(pData, m);
466	} /* switch */
467
468	end_error:
469	/* m is m_free()'d xor put in a socket xor or given to ip_send */
470	;
471	}
472
473
474	/*
475	* Send an ICMP message in response to a situation
476	*
477	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
478	* MUST NOT change this header information.
479	* MUST NOT reply to a multicast/broadcast IP address.
480	* MUST NOT reply to a multicast/broadcast MAC address.
481	* MUST reply to only the first fragment.
482	*/
483	/*
484	* Send ICMP_UNREACH back to the source regarding msrc.
485	* mbuf *msrc is used as a template, but is NOT m_free()'d.
486	* It is reported as the bad ip packet. The header should
487	* be fully correct and in host byte order.
488	* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
489	* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
490	*/
491
492	#define ICMP_MAXDATALEN (IP_MSS-28)
493	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
494	{
495	unsigned hlen, shlen, s_ip_len;
496	register struct ip *ip;
497	register struct icmp *icp;
498	register struct mbuf *m;
499
500	DEBUG_CALL("icmp_error");
501	DEBUG_ARG("msrc = %lx", (long )msrc);
502	DEBUG_ARG("msrc_len = %d", msrc->m_len);
503
504	if (type!=ICMP_UNREACH && type!=ICMP_TIMXCEED)
505	goto end_error;
506
507	/* check msrc */
508	if (!msrc)
509	goto end_error;
510
511	ip = mtod(msrc, struct ip *);
512	#if DEBUG
513	{
514	char bufa[20], bufb[20];
515	strcpy(bufa, inet_ntoa(ip->ip_src));
516	strcpy(bufb, inet_ntoa(ip->ip_dst));
517	DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
518	}
519	#endif
520	if (ip->ip_off & IP_OFFMASK)
521	goto end_error; /* Only reply to fragment 0 */
522
523	shlen = ip->ip_hl << 2;
524	s_ip_len = ip->ip_len;
525	if (ip->ip_p == IPPROTO_ICMP)
526	{
527	icp = (struct icmp )((char )ip + shlen);
528	/*
529	* Assume any unknown ICMP type is an error. This isn't
530	* specified by the RFC, but think about it..
531	*/
532	if (icp->icmp_type>18 \|\| icmp_flush[icp->icmp_type])
533	goto end_error;
534	}
535
536	/* make a copy */
537	if (!(m = m_get(pData)))
538	goto end_error; /* get mbuf */
539	{
540	int new_m_size;
541	m_adj(m, if_maxlinkhdr);
542	new_m_size = sizeof(struct ip) + ICMP_MINLEN + msrc->m_len + ICMP_MAXDATALEN;
543	if (new_m_size>m->m_size)
544	m_inc(m, new_m_size);
545	}
546
547	memcpy(m->m_data, msrc->m_data, msrc->m_len);
548	m->m_len = msrc->m_len; /* copy msrc to m */
549
550	/* make the header of the reply packet */
551	ip = mtod(m, struct ip *);
552	hlen = sizeof(struct ip ); /* no options in reply */
553
554	/* fill in icmp */
555	m->m_data += hlen;
556	m->m_len -= hlen;
557
558	icp = mtod(m, struct icmp *);
559
560	if (minsize)
561	s_ip_len = shlen+ICMP_MINLEN; /* return header+8b only */
562	else if (s_ip_len > ICMP_MAXDATALEN) /* maximum size */
563	s_ip_len = ICMP_MAXDATALEN;
564
565	m->m_len = ICMP_MINLEN + s_ip_len; /* 8 bytes ICMP header */
566
567	/* min. size = 8+sizeof(struct ip)+8 */
568
569	icp->icmp_type = type;
570	icp->icmp_code = code;
571	icp->icmp_id = 0;
572	icp->icmp_seq = 0;
573
574	memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
575	HTONS(icp->icmp_ip.ip_len);
576	HTONS(icp->icmp_ip.ip_id);
577	HTONS(icp->icmp_ip.ip_off);
578
579	#if DEBUG
580	if (message)
581	{
582	/* DEBUG : append message to ICMP packet */
583	int message_len;
584	char *cpnt;
585	message_len = strlen(message);
586	if (message_len > ICMP_MAXDATALEN)
587	message_len = ICMP_MAXDATALEN;
588	cpnt = (char *)m->m_data+m->m_len;
589	memcpy(cpnt, message, message_len);
590	m->m_len += message_len;
591	}
592	#endif
593
594	icp->icmp_cksum = 0;
595	icp->icmp_cksum = cksum(m, m->m_len);
596
597	m->m_data -= hlen;
598	m->m_len += hlen;
599
600	/* fill in ip */
601	ip->ip_hl = hlen >> 2;
602	ip->ip_len = m->m_len;
603
604	ip->ip_tos = ((ip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
605
606	ip->ip_ttl = MAXTTL;
607	ip->ip_p = IPPROTO_ICMP;
608	ip->ip_dst = ip->ip_src; /* ip adresses */
609	ip->ip_src = alias_addr;
610
611	(void ) ip_output(pData, (struct socket *)NULL, m);
612
613	icmpstat.icps_reflect++;
614
615	return;
616
617	end_error:
618	LogRel(("NAT: error occured while sending ICMP error message \n"));
619	}
620	#undef ICMP_MAXDATALEN
621
622	/*
623	* Reflect the ip packet back to the source
624	*/
625	void
626	icmp_reflect(PNATState pData, struct mbuf *m)
627	{
628	register struct ip ip = mtod(m, struct ip );
629	int hlen = ip->ip_hl << 2;
630	int optlen = hlen - sizeof(struct ip );
631	register struct icmp *icp;
632
633	/*
634	* Send an icmp packet back to the ip level,
635	* after supplying a checksum.
636	*/
637	m->m_data += hlen;
638	m->m_len -= hlen;
639	icp = mtod(m, struct icmp *);
640
641	icp->icmp_cksum = 0;
642	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
643
644	m->m_data -= hlen;
645	m->m_len += hlen;
646
647	(void ) ip_output(pData, (struct socket *)NULL, m);
648
649	icmpstat.icps_reflect++;
650	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 20703

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