ip_icmp.c@ 39085

Last change on this file since 39085 was 39085, checked in by vboxsync, 13 years ago
NAT: warnings.
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1	/* $Id: ip_icmp.c 39085 2011-10-24 06:58:33Z vboxsync $ */
2	/** @file
3	* NAT - IP/ICMP handling.
4	*/
5
6	/*
7	* Copyright (C) 2006-2010 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*/
17
18	/*
19	* This code is based on:
20	*
21	* Copyright (c) 1982, 1986, 1988, 1993
22	* The Regents of the University of California. All rights reserved.
23	*
24	* Redistribution and use in source and binary forms, with or without
25	* modification, are permitted provided that the following conditions
26	* are met:
27	* 1. Redistributions of source code must retain the above copyright
28	* notice, this list of conditions and the following disclaimer.
29	* 2. Redistributions in binary form must reproduce the above copyright
30	* notice, this list of conditions and the following disclaimer in the
31	* documentation and/or other materials provided with the distribution.
32	* 3. All advertising materials mentioning features or use of this software
33	* must display the following acknowledgement:
34	* This product includes software developed by the University of
35	* California, Berkeley and its contributors.
36	* 4. Neither the name of the University nor the names of its contributors
37	* may be used to endorse or promote products derived from this software
38	* without specific prior written permission.
39	*
40	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
41	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
44	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50	* SUCH DAMAGE.
51	*
52	* @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
53	* ip_icmp.c,v 1.7 1995/05/30 08:09:42 rgrimes Exp
54	*/
55
56	#include "slirp.h"
57	#include "ip_icmp.h"
58	#ifdef RT_OS_WINDOWS
59	#include <Icmpapi.h>
60	#include <Iphlpapi.h>
61	#endif
62
63	/* The message sent when emulating PING */
64	/* Be nice and tell them it's just a psuedo-ping packet */
65	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
66
67	/* list of actions for icmp_error() on RX of an icmp message */
68	static const int icmp_flush[19] =
69	{
70	/* ECHO REPLY (0) */ 0,
71	1,
72	1,
73	/* DEST UNREACH (3) */ 1,
74	/* SOURCE QUENCH (4)*/ 1,
75	/* REDIRECT (5) */ 1,
76	1,
77	1,
78	/* ECHO (8) */ 0,
79	/* ROUTERADVERT (9) */ 1,
80	/* ROUTERSOLICIT (10) */ 1,
81	/* TIME EXCEEDED (11) */ 1,
82	/* PARAMETER PROBLEM (12) */ 1,
83	/* TIMESTAMP (13) */ 0,
84	/* TIMESTAMP REPLY (14) */ 0,
85	/* INFO (15) */ 0,
86	/* INFO REPLY (16) */ 0,
87	/* ADDR MASK (17) */ 0,
88	/* ADDR MASK REPLY (18) */ 0
89	};
90
91	static void icmp_cache_clean(PNATState pData, int iEntries);
92
93	int
94	icmp_init(PNATState pData, int iIcmpCacheLimit)
95	{
96	pData->icmp_socket.so_type = IPPROTO_ICMP;
97	pData->icmp_socket.so_state = SS_ISFCONNECTED;
98	if (iIcmpCacheLimit < 0)
99	{
100	LogRel(("NAT: iIcmpCacheLimit is invalid %d, will be alter to default value 100\n", iIcmpCacheLimit));
101	iIcmpCacheLimit = 100;
102	}
103	pData->iIcmpCacheLimit = iIcmpCacheLimit;
104	#ifndef RT_OS_WINDOWS
105	# ifndef RT_OS_DARWIN
106	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
107	# else /* !RT_OS_DARWIN */
108	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
109	# endif /* RT_OS_DARWIN */
110	if (pData->icmp_socket.s == -1)
111	{
112	int rc = RTErrConvertFromErrno(errno);
113	LogRel(("NAT: ICMP/ping not available (could not open ICMP socket, error %Rrc)\n", rc));
114	return 1;
115	}
116	fd_nonblock(pData->icmp_socket.s);
117	NSOCK_INC();
118	#else /* RT_OS_WINDOWS */
119	pData->hmIcmpLibrary = LoadLibrary("Iphlpapi.dll");
120	if (pData->hmIcmpLibrary != NULL)
121	{
122	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
123	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
124	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
125	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
126	pData->pfGetAdaptersAddresses = (ULONG (WINAPI *)(ULONG, ULONG, PVOID, PIP_ADAPTER_ADDRESSES, PULONG))
127	GetProcAddress(pData->hmIcmpLibrary, "GetAdaptersAddresses");
128	if (pData->pfGetAdaptersAddresses == NULL)
129	{
130	LogRel(("NAT: Can't find GetAdapterAddresses in Iphlpapi.dll\n"));
131	}
132	}
133
134	if (pData->pfIcmpParseReplies == NULL)
135	{
136	if(pData->pfGetAdaptersAddresses == NULL)
137	FreeLibrary(pData->hmIcmpLibrary);
138	pData->hmIcmpLibrary = LoadLibrary("Icmp.dll");
139	if (pData->hmIcmpLibrary == NULL)
140	{
141	LogRel(("NAT: Icmp.dll could not be loaded\n"));
142	return 1;
143	}
144	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
145	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
146	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
147	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
148	}
149	if (pData->pfIcmpParseReplies == NULL)
150	{
151	LogRel(("NAT: Can't find IcmpParseReplies symbol\n"));
152	FreeLibrary(pData->hmIcmpLibrary);
153	return 1;
154	}
155	if (pData->pfIcmpCloseHandle == NULL)
156	{
157	LogRel(("NAT: Can't find IcmpCloseHandle symbol\n"));
158	FreeLibrary(pData->hmIcmpLibrary);
159	return 1;
160	}
161	pData->icmp_socket.sh = IcmpCreateFile();
162	pData->phEvents[VBOX_ICMP_EVENT_INDEX] = CreateEvent(NULL, FALSE, FALSE, NULL);
163	pData->szIcmpBuffer = sizeof(ICMP_ECHO_REPLY) * 10;
164	pData->pvIcmpBuffer = RTMemAlloc(pData->szIcmpBuffer);
165	#endif /* RT_OS_WINDOWS */
166	LIST_INIT(&pData->icmp_msg_head);
167	return 0;
168	}
169
170	/**
171	* Cleans ICMP cache.
172	*/
173	void
174	icmp_finit(PNATState pData)
175	{
176	icmp_cache_clean(pData, -1);
177	#ifdef RT_OS_WINDOWS
178	pData->pfIcmpCloseHandle(pData->icmp_socket.sh);
179	FreeLibrary(pData->hmIcmpLibrary);
180	RTMemFree(pData->pvIcmpBuffer);
181	#else
182	closesocket(pData->icmp_socket.s);
183	#endif
184	}
185
186	/*
187	* ip here is ip header + 64bytes readed from ICMP packet
188	*/
189	struct icmp_msg *
190	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
191	{
192	struct mbuf *m0;
193	struct ip *ip0;
194	struct icmp icp, icp0;
195	struct icmp_msg *icm = NULL;
196	int found = 0;
197	struct udphdr *udp;
198	struct tcphdr *tcp;
199	struct socket *head_socket = NULL;
200	struct socket *last_socket = NULL;
201	struct socket *so = NULL;
202	struct in_addr laddr, faddr;
203	u_short lport, fport;
204
205	laddr.s_addr = ~0;
206	faddr.s_addr = ~0;
207
208	lport = ~0;
209	fport = ~0;
210
211
212	LogFlowFunc(("ENTER: ip->ip_p:%d\n", ip->ip_p));
213	switch (ip->ip_p)
214	{
215	case IPPROTO_ICMP:
216	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
217	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
218	{
219	m0 = icm->im_m;
220	ip0 = mtod(m0, struct ip *);
221	if (ip0->ip_p != IPPROTO_ICMP)
222	{
223	/* try next item */
224	continue;
225	}
226	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
227	/*
228	* IP could pointer to ICMP_REPLY datagram (1)
229	* or pointer IP header in ICMP payload in case of
230	* ICMP_TIMXCEED or ICMP_UNREACH (2)
231	*
232	* if (1) and then ICMP (type should be ICMP_ECHOREPLY) and we need check that
233	* IP.IP_SRC == IP0.IP_DST received datagramm comes from destination.
234	*
235	* if (2) then check that payload ICMP has got type ICMP_ECHO and
236	* IP.IP_DST == IP0.IP_DST destination of returned datagram is the same as
237	* one was sent.
238	*/
239	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
240	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
241	&& icp->icmp_id == icp0->icmp_id
242	&& icp->icmp_seq == icp0->icmp_seq)
243	{
244	found = 1;
245	Log(("Have found %R[natsock]\n", icm->im_so));
246	break;
247	}
248	Log(("Have found nothing\n"));
249	}
250	break;
251
252	/*
253	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
254	* from which the IP package has been sent.
255	*/
256	case IPPROTO_UDP:
257	head_socket = &udb;
258	udp = (struct udphdr )((char )ip + (ip->ip_hl << 2));
259	faddr.s_addr = ip->ip_dst.s_addr;
260	fport = udp->uh_dport;
261	laddr.s_addr = ip->ip_src.s_addr;
262	lport = udp->uh_sport;
263	last_socket = udp_last_so;
264	/* fall through */
265
266	case IPPROTO_TCP:
267	if (head_socket == NULL)
268	{
269	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
270	head_socket = &tcb; /* head_socket could be initialized with udb*/
271	faddr.s_addr = ip->ip_dst.s_addr;
272	fport = tcp->th_dport;
273	laddr.s_addr = ip->ip_src.s_addr;
274	lport = tcp->th_sport;
275	last_socket = tcp_last_so;
276	}
277	/* check last socket first */
278	if ( last_socket->so_faddr.s_addr == faddr.s_addr
279	&& last_socket->so_fport == fport
280	&& last_socket->so_hlport == lport)
281	{
282	found = 1;
283	so = last_socket;
284	goto sofound;
285	}
286	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
287	{
288	/* Should be reaplaced by hash here */
289	Log(("trying:%R[natsock] against %RTnaipv4:%d lport=%d hlport=%d\n", so, &faddr, fport, lport, so->so_hlport));
290	if ( so->so_faddr.s_addr == faddr.s_addr
291	&& so->so_fport == fport
292	&& so->so_hlport == lport)
293	{
294	found = 1;
295	break;
296	}
297	}
298	break;
299
300	default:
301	Log(("NAT:ICMP: unsupported protocol(%d)\n", ip->ip_p));
302	}
303	sofound:
304	if (found == 1 && icm == NULL)
305	{
306	if (so->so_state == SS_NOFDREF)
307	{
308	/* socket is shutdowning we've already sent ICMP on it.*/
309	Log(("NAT: Received icmp on shutdowning socket (probably corresponding ICMP socket has been already sent)\n"));
310	return NULL;
311	}
312	icm = RTMemAlloc(sizeof(struct icmp_msg));
313	icm->im_m = so->so_m;
314	icm->im_so = so;
315	found = 1;
316	Log(("hit:%R[natsock]\n", so));
317	/*XXX: this storage not very long,
318	* better add flag if it should removed from lis
319	*/
320	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
321	pData->cIcmpCacheSize++;
322	if (pData->cIcmpCacheSize > pData->iIcmpCacheLimit)
323	icmp_cache_clean(pData, pData->iIcmpCacheLimit/2);
324	LogFlowFunc(("LEAVE: icm:%p\n", icm));
325	return (icm);
326	}
327	if (found == 1)
328	{
329	LogFlowFunc(("LEAVE: icm:%p\n", icm));
330	return icm;
331	}
332
333	LogFlowFunc(("LEAVE: NULL\n"));
334	return NULL;
335	}
336
337	/**
338	* iEntries how many entries to leave, if iEntries < 0, clean all
339	*/
340	static void icmp_cache_clean(PNATState pData, int iEntries)
341	{
342	int iIcmpCount = 0;
343	struct icmp_msg *icm = NULL;
344	LogFlowFunc(("iEntries:%d\n", iEntries));
345	if (iEntries > pData->cIcmpCacheSize)
346	{
347	LogFlowFuncLeave();
348	return;
349	}
350	while(!LIST_EMPTY(&pData->icmp_msg_head))
351	{
352	icm = LIST_FIRST(&pData->icmp_msg_head);
353	if ( iEntries > 0
354	&& iIcmpCount < iEntries)
355	{
356	iIcmpCount++;
357	continue;
358	}
359
360	LIST_REMOVE(icm, im_list);
361	if (icm->im_m)
362	{
363	pData->cIcmpCacheSize--;
364	m_freem(pData, icm->im_m);
365	}
366	RTMemFree(icm);
367	}
368	LogFlowFuncLeave();
369	}
370
371	static int
372	icmp_attach(PNATState pData, struct mbuf *m)
373	{
374	struct icmp_msg *icm;
375	struct ip *ip;
376	ip = mtod(m, struct ip *);
377	Assert(ip->ip_p == IPPROTO_ICMP);
378	icm = RTMemAlloc(sizeof(struct icmp_msg));
379	icm->im_m = m;
380	icm->im_so = m->m_so;
381	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
382	pData->cIcmpCacheSize++;
383	if (pData->cIcmpCacheSize > pData->iIcmpCacheLimit)
384	icmp_cache_clean(pData, pData->iIcmpCacheLimit/2);
385	return 0;
386	}
387
388	/*
389	* Process a received ICMP message.
390	*/
391	void
392	icmp_input(PNATState pData, struct mbuf *m, int hlen)
393	{
394	register struct icmp *icp;
395	void *icp_buf = NULL;
396	register struct ip ip = mtod(m, struct ip );
397	int icmplen = ip->ip_len;
398	int status;
399	uint32_t dst;
400	#if !defined(RT_OS_WINDOWS)
401	int ttl;
402	#endif
403
404	/* int code; */
405
406	LogFlowFunc(("ENTER: m = %lx, m_len = %d\n", (long)m, m ? m->m_len : 0));
407
408	icmpstat.icps_received++;
409
410	/*
411	* Locate icmp structure in mbuf, and check
412	* that its not corrupted and of at least minimum length.
413	*/
414	if (icmplen < ICMP_MINLEN)
415	{
416	/* min 8 bytes payload */
417	icmpstat.icps_tooshort++;
418	goto end_error_free_m;
419	}
420
421	m->m_len -= hlen;
422	m->m_data += hlen;
423
424	if (cksum(m, icmplen))
425	{
426	icmpstat.icps_checksum++;
427	goto end_error_free_m;
428	}
429
430	if (m->m_next)
431	{
432	icp_buf = RTMemAlloc(icmplen);
433	if (!icp_buf)
434	{
435	Log(("NAT: not enought memory to allocate the buffer\n"));
436	goto end_error_free_m;
437	}
438	m_copydata(m, 0, icmplen, icp_buf);
439	icp = (struct icmp *)icp_buf;
440	}
441	else
442	icp = mtod(m, struct icmp *);
443
444	m->m_len += hlen;
445	m->m_data -= hlen;
446
447	/* icmpstat.icps_inhist[icp->icmp_type]++; */
448	/* code = icp->icmp_code; */
449
450	LogFlow(("icmp_type = %d\n", icp->icmp_type));
451	switch (icp->icmp_type)
452	{
453	case ICMP_ECHO:
454	ip->ip_len += hlen; /* since ip_input subtracts this */
455	dst = ip->ip_dst.s_addr;
456	if (dst == alias_addr.s_addr)
457	{
458	icp->icmp_type = ICMP_ECHOREPLY;
459	ip->ip_dst.s_addr = ip->ip_src.s_addr;
460	ip->ip_src.s_addr = dst;
461	icmp_reflect(pData, m);
462	goto done;
463	}
464	else
465	{
466	struct sockaddr_in addr;
467	#ifdef RT_OS_WINDOWS
468	IP_OPTION_INFORMATION ipopt;
469	int error;
470	#endif
471	addr.sin_family = AF_INET;
472	if ((ip->ip_dst.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr)
473	{
474	/* It's an alias */
475	switch (RT_N2H_U32(ip->ip_dst.s_addr) & ~pData->netmask)
476	{
477	case CTL_DNS:
478	case CTL_ALIAS:
479	default:
480	addr.sin_addr = loopback_addr;
481	break;
482	}
483	}
484	else
485	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
486	#ifndef RT_OS_WINDOWS
487	if (pData->icmp_socket.s != -1)
488	{
489	ssize_t rc;
490	static bool fIcmpSocketErrorReported;
491	ttl = ip->ip_ttl;
492	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
493	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
494	(void *)&ttl, sizeof(ttl));
495	if (status < 0)
496	Log(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
497	strerror(errno)));
498	rc = sendto(pData->icmp_socket.s, icp, icmplen, 0,
499	(struct sockaddr *)&addr, sizeof(addr));
500	if (rc >= 0)
501	{
502	m->m_so = &pData->icmp_socket;
503	icmp_attach(pData, m);
504	/* don't let m_freem at the end free atached buffer */
505	goto done;
506	}
507
508
509	if (!fIcmpSocketErrorReported)
510	{
511	LogRel(("icmp_input udp sendto tx errno = %d (%s)\n",
512	errno, strerror(errno)));
513	fIcmpSocketErrorReported = true;
514	}
515	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
516	}
517	#else /* RT_OS_WINDOWS */
518	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
519	pData->icmp_socket.so_icmp_id = icp->icmp_id;
520	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
521	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
522	ipopt.Ttl = ip->ip_ttl;
523	status = IcmpSendEcho2(pData->icmp_socket.sh /=handle/,
524	pData->phEvents[VBOX_ICMP_EVENT_INDEX] /=Event/,
525	NULL /=ApcRoutine/,
526	NULL /=ApcContext/,
527	addr.sin_addr.s_addr /=DestinationAddress/,
528	icp->icmp_data /=RequestData/,
529	icmplen - ICMP_MINLEN /=RequestSize/,
530	&ipopt /=RequestOptions/,
531	pData->pvIcmpBuffer /=ReplyBuffer/,
532	pData->szIcmpBuffer /=ReplySize/,
533	1 /=Timeout in ms/);
534	error = GetLastError();
535	if ( status != 0
536	\|\| error == ERROR_IO_PENDING)
537	{
538	/* no error! */
539	m->m_so = &pData->icmp_socket;
540	icmp_attach(pData, m);
541	/* don't let m_freem at the end free atached buffer */
542	goto done;
543	}
544	Log(("NAT: Error (%d) occurred while sending ICMP (", error));
545	switch (error)
546	{
547	case ERROR_INVALID_PARAMETER:
548	Log(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
549	break;
550	case ERROR_NOT_SUPPORTED:
551	Log(("operation is unsupported)\n"));
552	break;
553	case ERROR_NOT_ENOUGH_MEMORY:
554	Log(("OOM!!!)\n"));
555	break;
556	case IP_BUF_TOO_SMALL:
557	Log(("Buffer too small)\n"));
558	break;
559	default:
560	Log(("Other error!!!)\n"));
561	break;
562	}
563	#endif /* RT_OS_WINDOWS */
564	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
565	break;
566	case ICMP_UNREACH:
567	case ICMP_TIMXCEED:
568	/* @todo(vvl): both up cases comes from guest,
569	* indeed right solution would be find the socket
570	* corresponding to ICMP data and close it.
571	*/
572	case ICMP_PARAMPROB:
573	case ICMP_SOURCEQUENCH:
574	case ICMP_TSTAMP:
575	case ICMP_MASKREQ:
576	case ICMP_REDIRECT:
577	icmpstat.icps_notsupp++;
578	break;
579
580	default:
581	icmpstat.icps_badtype++;
582	} /* switch */
583
584	end_error_free_m:
585	m_freem(pData, m);
586
587	done:
588	if (icp_buf)
589	RTMemFree(icp_buf);
590	}
591
592
593	/**
594	* Send an ICMP message in response to a situation
595	*
596	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
597	* MUST NOT change this header information.
598	* MUST NOT reply to a multicast/broadcast IP address.
599	* MUST NOT reply to a multicast/broadcast MAC address.
600	* MUST reply to only the first fragment.
601	*
602	* Send ICMP_UNREACH back to the source regarding msrc.
603	* It is reported as the bad ip packet. The header should
604	* be fully correct and in host byte order.
605	* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
606	* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
607	*
608	* @note This function will free msrc!
609	*/
610
611	#define ICMP_MAXDATALEN (IP_MSS-28)
612	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
613	{
614	unsigned hlen, shlen, s_ip_len;
615	register struct ip *ip;
616	register struct icmp *icp;
617	register struct mbuf *m;
618	int new_m_size = 0;
619	int size = 0;
620
621	LogFlow(("icmp_error: msrc = %lx, msrc_len = %d\n", (long)msrc, msrc ? msrc->m_len : 0));
622	if (msrc != NULL)
623	M_ASSERTPKTHDR(msrc);
624
625	if ( type != ICMP_UNREACH
626	&& type != ICMP_TIMXCEED
627	&& type != ICMP_SOURCEQUENCH)
628	goto end_error;
629
630	/* check msrc */
631	if (!msrc)
632	goto end_error;
633
634	ip = mtod(msrc, struct ip *);
635	#if DEBUG
636	{
637	char bufa[20], bufb[20];
638	strcpy(bufa, inet_ntoa(ip->ip_src));
639	strcpy(bufb, inet_ntoa(ip->ip_dst));
640	Log2((" %.16s to %.16s\n", bufa, bufb));
641	}
642	#endif
643	if ( ip->ip_off & IP_OFFMASK
644	&& type != ICMP_SOURCEQUENCH)
645	goto end_error; /* Only reply to fragment 0 */
646
647	shlen = ip->ip_hl << 2;
648	s_ip_len = ip->ip_len;
649	if (ip->ip_p == IPPROTO_ICMP)
650	{
651	icp = (struct icmp )((char )ip + shlen);
652	/*
653	* Assume any unknown ICMP type is an error. This isn't
654	* specified by the RFC, but think about it..
655	*/
656	if (icp->icmp_type>18 \|\| icmp_flush[icp->icmp_type])
657	goto end_error;
658	}
659
660	new_m_size = sizeof(struct ip) + ICMP_MINLEN + msrc->m_len + ICMP_MAXDATALEN;
661	if (new_m_size < MSIZE)
662	size = MCLBYTES;
663	else if (new_m_size < MCLBYTES)
664	size = MCLBYTES;
665	else if(new_m_size < MJUM9BYTES)
666	size = MJUM9BYTES;
667	else if (new_m_size < MJUM16BYTES)
668	size = MJUM16BYTES;
669	else
670	AssertMsgFailed(("Unsupported size"));
671	m = m_getjcl(pData, M_NOWAIT, MT_HEADER, M_PKTHDR, size);
672	if (!m)
673	goto end_error;
674
675	m->m_data += if_maxlinkhdr;
676	m->m_pkthdr.header = mtod(m, void *);
677
678	memcpy(m->m_data, msrc->m_data, msrc->m_len);
679	m->m_len = msrc->m_len; /* copy msrc to m */
680
681	/* make the header of the reply packet */
682	ip = mtod(m, struct ip *);
683	hlen = sizeof(struct ip); /* no options in reply */
684
685	/* fill in icmp */
686	m->m_data += hlen;
687	m->m_len -= hlen;
688
689	icp = mtod(m, struct icmp *);
690
691	if (minsize)
692	s_ip_len = shlen+ICMP_MINLEN; /* return header+8b only */
693	else if (s_ip_len > ICMP_MAXDATALEN) /* maximum size */
694	s_ip_len = ICMP_MAXDATALEN;
695
696	m->m_len = ICMP_MINLEN + s_ip_len; /* 8 bytes ICMP header */
697
698	/* min. size = 8+sizeof(struct ip)+8 */
699
700	icp->icmp_type = type;
701	icp->icmp_code = code;
702	icp->icmp_id = 0;
703	icp->icmp_seq = 0;
704
705	memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
706
707	HTONS(icp->icmp_ip.ip_len);
708	HTONS(icp->icmp_ip.ip_id);
709	HTONS(icp->icmp_ip.ip_off);
710
711	#if DEBUG
712	if (message)
713	{
714	/* DEBUG : append message to ICMP packet */
715	int message_len;
716	char *cpnt;
717	message_len = strlen(message);
718	if (message_len > ICMP_MAXDATALEN)
719	message_len = ICMP_MAXDATALEN;
720	cpnt = (char *)m->m_data+m->m_len;
721	m_append(pData, m, message_len, message);
722	}
723	#endif
724
725	icp->icmp_cksum = 0;
726	icp->icmp_cksum = cksum(m, m->m_len);
727
728	/* fill in ip */
729	ip->ip_hl = hlen >> 2;
730	ip->ip_len = m->m_len;
731
732	ip->ip_tos = ((ip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
733
734	ip->ip_ttl = MAXTTL;
735	ip->ip_p = IPPROTO_ICMP;
736	ip->ip_dst = ip->ip_src; /* ip adresses */
737	ip->ip_src = alias_addr;
738
739	/* returns pointer back. */
740	m->m_data -= hlen;
741	m->m_len += hlen;
742	(void) ip_output0(pData, (struct socket *)NULL, m, 1);
743
744	icmpstat.icps_reflect++;
745
746	/* clear source datagramm in positive branch */
747	m_freem(pData, msrc);
748	LogFlowFuncLeave();
749	return;
750
751	end_error_free_m:
752	m_freem(pData, m);
753
754	end_error:
755
756	/*
757	* clear source datagramm in case if some of requirement haven't been met.
758	*/
759	if (!msrc)
760	m_freem(pData, msrc);
761
762	{
763	static bool fIcmpErrorReported;
764	if (!fIcmpErrorReported)
765	{
766	LogRel(("NAT: error occurred while sending ICMP error message\n"));
767	fIcmpErrorReported = true;
768	}
769	}
770	LogFlowFuncLeave();
771	}
772	#undef ICMP_MAXDATALEN
773
774	/*
775	* Reflect the ip packet back to the source
776	* Note: m isn't duplicated by this method and more delivered to ip_output then.
777	*/
778	void
779	icmp_reflect(PNATState pData, struct mbuf *m)
780	{
781	register struct ip ip = mtod(m, struct ip );
782	int hlen = ip->ip_hl << 2;
783	register struct icmp *icp;
784	LogFlowFunc(("ENTER: m:%p\n", m));
785
786	/*
787	* Send an icmp packet back to the ip level,
788	* after supplying a checksum.
789	*/
790	m->m_data += hlen;
791	m->m_len -= hlen;
792	icp = mtod(m, struct icmp *);
793
794	icp->icmp_cksum = 0;
795	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
796
797	m->m_data -= hlen;
798	m->m_len += hlen;
799
800	(void) ip_output(pData, (struct socket *)NULL, m);
801
802	icmpstat.icps_reflect++;
803	LogFlowFuncLeave();
804	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 39085

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