ip_icmp.c@ 40421

Last change on this file since 40421 was 40421, checked in by vboxsync, 13 years ago
NAT: warnings [-Wunused-but-set-variable]
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 25.8 KB

Line
1	/* $Id: ip_icmp.c 40421 2012-03-11 02:28:13Z 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	#define NEED_SOME_m_getjcl
57	#include "slirp.h"
58	#include "ip_icmp.h"
59	#ifdef RT_OS_WINDOWS
60	#include <Icmpapi.h>
61	#include <Iphlpapi.h>
62	#endif
63
64	/* The message sent when emulating PING */
65	/* Be nice and tell them it's just a psuedo-ping packet */
66	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
67
68	/* list of actions for icmp_error() on RX of an icmp message */
69	static const int icmp_flush[19] =
70	{
71	/* ECHO REPLY (0) */ 0,
72	1,
73	1,
74	/* DEST UNREACH (3) */ 1,
75	/* SOURCE QUENCH (4)*/ 1,
76	/* REDIRECT (5) */ 1,
77	1,
78	1,
79	/* ECHO (8) */ 0,
80	/* ROUTERADVERT (9) */ 1,
81	/* ROUTERSOLICIT (10) */ 1,
82	/* TIME EXCEEDED (11) */ 1,
83	/* PARAMETER PROBLEM (12) */ 1,
84	/* TIMESTAMP (13) */ 0,
85	/* TIMESTAMP REPLY (14) */ 0,
86	/* INFO (15) */ 0,
87	/* INFO REPLY (16) */ 0,
88	/* ADDR MASK (17) */ 0,
89	/* ADDR MASK REPLY (18) */ 0
90	};
91
92	static void icmp_cache_clean(PNATState pData, int iEntries);
93
94	int
95	icmp_init(PNATState pData, int iIcmpCacheLimit)
96	{
97	pData->icmp_socket.so_type = IPPROTO_ICMP;
98	pData->icmp_socket.so_state = SS_ISFCONNECTED;
99	if (iIcmpCacheLimit < 0)
100	{
101	LogRel(("NAT: iIcmpCacheLimit is invalid %d, will be alter to default value 100\n", iIcmpCacheLimit));
102	iIcmpCacheLimit = 100;
103	}
104	pData->iIcmpCacheLimit = iIcmpCacheLimit;
105	#ifndef RT_OS_WINDOWS
106	# ifndef RT_OS_DARWIN
107	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
108	# else /* !RT_OS_DARWIN */
109	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
110	# endif /* RT_OS_DARWIN */
111	if (pData->icmp_socket.s == -1)
112	{
113	int rc = RTErrConvertFromErrno(errno);
114	LogRel(("NAT: ICMP/ping not available (could not open ICMP socket, error %Rrc)\n", rc));
115	return 1;
116	}
117	fd_nonblock(pData->icmp_socket.s);
118	NSOCK_INC();
119	#else /* RT_OS_WINDOWS */
120	pData->hmIcmpLibrary = LoadLibrary("Iphlpapi.dll");
121	if (pData->hmIcmpLibrary != NULL)
122	{
123	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
124	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
125	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
126	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
127	pData->pfGetAdaptersAddresses = (ULONG (WINAPI *)(ULONG, ULONG, PVOID, PIP_ADAPTER_ADDRESSES, PULONG))
128	GetProcAddress(pData->hmIcmpLibrary, "GetAdaptersAddresses");
129	if (pData->pfGetAdaptersAddresses == NULL)
130	{
131	LogRel(("NAT: Can't find GetAdapterAddresses in Iphlpapi.dll\n"));
132	}
133	}
134
135	if (pData->pfIcmpParseReplies == NULL)
136	{
137	if(pData->pfGetAdaptersAddresses == NULL)
138	FreeLibrary(pData->hmIcmpLibrary);
139	pData->hmIcmpLibrary = LoadLibrary("Icmp.dll");
140	if (pData->hmIcmpLibrary == NULL)
141	{
142	LogRel(("NAT: Icmp.dll could not be loaded\n"));
143	return 1;
144	}
145	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
146	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
147	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
148	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
149	}
150	if (pData->pfIcmpParseReplies == NULL)
151	{
152	LogRel(("NAT: Can't find IcmpParseReplies symbol\n"));
153	FreeLibrary(pData->hmIcmpLibrary);
154	return 1;
155	}
156	if (pData->pfIcmpCloseHandle == NULL)
157	{
158	LogRel(("NAT: Can't find IcmpCloseHandle symbol\n"));
159	FreeLibrary(pData->hmIcmpLibrary);
160	return 1;
161	}
162	pData->icmp_socket.sh = IcmpCreateFile();
163	pData->phEvents[VBOX_ICMP_EVENT_INDEX] = CreateEvent(NULL, FALSE, FALSE, NULL);
164	pData->szIcmpBuffer = sizeof(ICMP_ECHO_REPLY) * 10;
165	pData->pvIcmpBuffer = RTMemAlloc(pData->szIcmpBuffer);
166	#endif /* RT_OS_WINDOWS */
167	LIST_INIT(&pData->icmp_msg_head);
168	return 0;
169	}
170
171	/**
172	* Cleans ICMP cache.
173	*/
174	void
175	icmp_finit(PNATState pData)
176	{
177	icmp_cache_clean(pData, -1);
178	#ifdef RT_OS_WINDOWS
179	pData->pfIcmpCloseHandle(pData->icmp_socket.sh);
180	FreeLibrary(pData->hmIcmpLibrary);
181	RTMemFree(pData->pvIcmpBuffer);
182	#else
183	closesocket(pData->icmp_socket.s);
184	#endif
185	}
186
187	/*
188	* ip here is ip header + 64bytes readed from ICMP packet
189	*/
190	struct icmp_msg *
191	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
192	{
193	struct mbuf *m0;
194	struct ip *ip0;
195	struct icmp icp, icp0;
196	struct icmp_msg *icm = NULL;
197	int found = 0;
198	struct udphdr *udp;
199	struct tcphdr *tcp;
200	struct socket *head_socket = NULL;
201	struct socket *last_socket = NULL;
202	struct socket *so = NULL;
203	struct in_addr faddr;
204	u_short lport, fport;
205
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	lport = udp->uh_sport;
262	last_socket = udp_last_so;
263	/* fall through */
264
265	case IPPROTO_TCP:
266	if (head_socket == NULL)
267	{
268	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
269	head_socket = &tcb; /* head_socket could be initialized with udb*/
270	faddr.s_addr = ip->ip_dst.s_addr;
271	fport = tcp->th_dport;
272	lport = tcp->th_sport;
273	last_socket = tcp_last_so;
274	}
275	/* check last socket first */
276	if ( last_socket->so_faddr.s_addr == faddr.s_addr
277	&& last_socket->so_fport == fport
278	&& last_socket->so_hlport == lport)
279	{
280	found = 1;
281	so = last_socket;
282	goto sofound;
283	}
284	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
285	{
286	/* Should be reaplaced by hash here */
287	Log(("trying:%R[natsock] against %RTnaipv4:%d lport=%d hlport=%d\n", so, &faddr, fport, lport, so->so_hlport));
288	if ( so->so_faddr.s_addr == faddr.s_addr
289	&& so->so_fport == fport
290	&& so->so_hlport == lport)
291	{
292	found = 1;
293	break;
294	}
295	}
296	break;
297
298	default:
299	Log(("NAT:ICMP: unsupported protocol(%d)\n", ip->ip_p));
300	}
301	sofound:
302	if (found == 1 && icm == NULL)
303	{
304	if (so->so_state == SS_NOFDREF)
305	{
306	/* socket is shutdowning we've already sent ICMP on it.*/
307	Log(("NAT: Received icmp on shutdowning socket (probably corresponding ICMP socket has been already sent)\n"));
308	return NULL;
309	}
310	icm = RTMemAlloc(sizeof(struct icmp_msg));
311	icm->im_m = so->so_m;
312	icm->im_so = so;
313	found = 1;
314	Log(("hit:%R[natsock]\n", so));
315	/*XXX: this storage not very long,
316	* better add flag if it should removed from lis
317	*/
318	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
319	pData->cIcmpCacheSize++;
320	if (pData->cIcmpCacheSize > pData->iIcmpCacheLimit)
321	icmp_cache_clean(pData, pData->iIcmpCacheLimit/2);
322	LogFlowFunc(("LEAVE: icm:%p\n", icm));
323	return (icm);
324	}
325	if (found == 1)
326	{
327	LogFlowFunc(("LEAVE: icm:%p\n", icm));
328	return icm;
329	}
330
331	LogFlowFunc(("LEAVE: NULL\n"));
332	return NULL;
333	}
334
335	/**
336	* iEntries how many entries to leave, if iEntries < 0, clean all
337	*/
338	static void icmp_cache_clean(PNATState pData, int iEntries)
339	{
340	int iIcmpCount = 0;
341	struct icmp_msg *icm = NULL;
342	LogFlowFunc(("iEntries:%d\n", iEntries));
343	if (iEntries > pData->cIcmpCacheSize)
344	{
345	LogFlowFuncLeave();
346	return;
347	}
348	while(!LIST_EMPTY(&pData->icmp_msg_head))
349	{
350	icm = LIST_FIRST(&pData->icmp_msg_head);
351	if ( iEntries > 0
352	&& iIcmpCount < iEntries)
353	{
354	iIcmpCount++;
355	continue;
356	}
357
358	LIST_REMOVE(icm, im_list);
359	if (icm->im_m)
360	{
361	pData->cIcmpCacheSize--;
362	m_freem(pData, icm->im_m);
363	}
364	RTMemFree(icm);
365	}
366	LogFlowFuncLeave();
367	}
368
369	static int
370	icmp_attach(PNATState pData, struct mbuf *m)
371	{
372	struct icmp_msg *icm;
373	struct ip *ip;
374	ip = mtod(m, struct ip *);
375	Assert(ip->ip_p == IPPROTO_ICMP);
376	icm = RTMemAlloc(sizeof(struct icmp_msg));
377	icm->im_m = m;
378	icm->im_so = m->m_so;
379	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
380	pData->cIcmpCacheSize++;
381	if (pData->cIcmpCacheSize > pData->iIcmpCacheLimit)
382	icmp_cache_clean(pData, pData->iIcmpCacheLimit/2);
383	return 0;
384	}
385
386	/*
387	* Process a received ICMP message.
388	*/
389	void
390	icmp_input(PNATState pData, struct mbuf *m, int hlen)
391	{
392	register struct icmp *icp;
393	void *icp_buf = NULL;
394	register struct ip ip = mtod(m, struct ip );
395	int icmplen = ip->ip_len;
396	int status;
397	uint32_t dst;
398	#if !defined(RT_OS_WINDOWS)
399	int ttl;
400	#endif
401
402	/* int code; */
403
404	LogFlowFunc(("ENTER: m = %lx, m_len = %d\n", (long)m, m ? m->m_len : 0));
405
406	icmpstat.icps_received++;
407
408	/*
409	* Locate icmp structure in mbuf, and check
410	* that its not corrupted and of at least minimum length.
411	*/
412	if (icmplen < ICMP_MINLEN)
413	{
414	/* min 8 bytes payload */
415	icmpstat.icps_tooshort++;
416	goto end_error_free_m;
417	}
418
419	m->m_len -= hlen;
420	m->m_data += hlen;
421
422	if (cksum(m, icmplen))
423	{
424	icmpstat.icps_checksum++;
425	goto end_error_free_m;
426	}
427
428	if (m->m_next)
429	{
430	icp_buf = RTMemAlloc(icmplen);
431	if (!icp_buf)
432	{
433	Log(("NAT: not enought memory to allocate the buffer\n"));
434	goto end_error_free_m;
435	}
436	m_copydata(m, 0, icmplen, icp_buf);
437	icp = (struct icmp *)icp_buf;
438	}
439	else
440	icp = mtod(m, struct icmp *);
441
442	m->m_len += hlen;
443	m->m_data -= hlen;
444
445	/* icmpstat.icps_inhist[icp->icmp_type]++; */
446	/* code = icp->icmp_code; */
447
448	LogFlow(("icmp_type = %d\n", icp->icmp_type));
449	switch (icp->icmp_type)
450	{
451	case ICMP_ECHO:
452	ip->ip_len += hlen; /* since ip_input subtracts this */
453	dst = ip->ip_dst.s_addr;
454	if (dst == alias_addr.s_addr)
455	{
456	icp->icmp_type = ICMP_ECHOREPLY;
457	ip->ip_dst.s_addr = ip->ip_src.s_addr;
458	ip->ip_src.s_addr = dst;
459	icmp_reflect(pData, m);
460	goto done;
461	}
462	else
463	{
464	struct sockaddr_in addr;
465	#ifdef RT_OS_WINDOWS
466	IP_OPTION_INFORMATION ipopt;
467	int error;
468	#endif
469	addr.sin_family = AF_INET;
470	if ((ip->ip_dst.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr)
471	{
472	/* It's an alias */
473	switch (RT_N2H_U32(ip->ip_dst.s_addr) & ~pData->netmask)
474	{
475	case CTL_DNS:
476	case CTL_ALIAS:
477	default:
478	addr.sin_addr = loopback_addr;
479	break;
480	}
481	}
482	else
483	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
484	#ifndef RT_OS_WINDOWS
485	if (pData->icmp_socket.s != -1)
486	{
487	ssize_t rc;
488	static bool fIcmpSocketErrorReported;
489	ttl = ip->ip_ttl;
490	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
491	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
492	(void *)&ttl, sizeof(ttl));
493	if (status < 0)
494	Log(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
495	strerror(errno)));
496	rc = sendto(pData->icmp_socket.s, icp, icmplen, 0,
497	(struct sockaddr *)&addr, sizeof(addr));
498	if (rc >= 0)
499	{
500	m->m_so = &pData->icmp_socket;
501	icmp_attach(pData, m);
502	/* don't let m_freem at the end free atached buffer */
503	goto done;
504	}
505
506
507	if (!fIcmpSocketErrorReported)
508	{
509	LogRel(("icmp_input udp sendto tx errno = %d (%s)\n",
510	errno, strerror(errno)));
511	fIcmpSocketErrorReported = true;
512	}
513	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
514	}
515	#else /* RT_OS_WINDOWS */
516	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
517	pData->icmp_socket.so_icmp_id = icp->icmp_id;
518	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
519	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
520	ipopt.Ttl = ip->ip_ttl;
521	status = IcmpSendEcho2(pData->icmp_socket.sh /=handle/,
522	pData->phEvents[VBOX_ICMP_EVENT_INDEX] /=Event/,
523	NULL /=ApcRoutine/,
524	NULL /=ApcContext/,
525	addr.sin_addr.s_addr /=DestinationAddress/,
526	icp->icmp_data /=RequestData/,
527	icmplen - ICMP_MINLEN /=RequestSize/,
528	&ipopt /=RequestOptions/,
529	pData->pvIcmpBuffer /=ReplyBuffer/,
530	pData->szIcmpBuffer /=ReplySize/,
531	1 /=Timeout in ms/);
532	error = GetLastError();
533	if ( status != 0
534	\|\| error == ERROR_IO_PENDING)
535	{
536	/* no error! */
537	m->m_so = &pData->icmp_socket;
538	icmp_attach(pData, m);
539	/* don't let m_freem at the end free atached buffer */
540	goto done;
541	}
542	Log(("NAT: Error (%d) occurred while sending ICMP (", error));
543	switch (error)
544	{
545	case ERROR_INVALID_PARAMETER:
546	Log(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
547	break;
548	case ERROR_NOT_SUPPORTED:
549	Log(("operation is unsupported)\n"));
550	break;
551	case ERROR_NOT_ENOUGH_MEMORY:
552	Log(("OOM!!!)\n"));
553	break;
554	case IP_BUF_TOO_SMALL:
555	Log(("Buffer too small)\n"));
556	break;
557	default:
558	Log(("Other error!!!)\n"));
559	break;
560	}
561	#endif /* RT_OS_WINDOWS */
562	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
563	break;
564	case ICMP_UNREACH:
565	case ICMP_TIMXCEED:
566	/* @todo(vvl): both up cases comes from guest,
567	* indeed right solution would be find the socket
568	* corresponding to ICMP data and close it.
569	*/
570	case ICMP_PARAMPROB:
571	case ICMP_SOURCEQUENCH:
572	case ICMP_TSTAMP:
573	case ICMP_MASKREQ:
574	case ICMP_REDIRECT:
575	icmpstat.icps_notsupp++;
576	break;
577
578	default:
579	icmpstat.icps_badtype++;
580	} /* switch */
581
582	end_error_free_m:
583	m_freem(pData, m);
584
585	done:
586	if (icp_buf)
587	RTMemFree(icp_buf);
588	}
589
590
591	/**
592	* Send an ICMP message in response to a situation
593	*
594	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
595	* MUST NOT change this header information.
596	* MUST NOT reply to a multicast/broadcast IP address.
597	* MUST NOT reply to a multicast/broadcast MAC address.
598	* MUST reply to only the first fragment.
599	*
600	* Send ICMP_UNREACH back to the source regarding msrc.
601	* It is reported as the bad ip packet. The header should
602	* be fully correct and in host byte order.
603	* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
604	* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
605	*
606	* @note This function will free msrc!
607	*/
608
609	#define ICMP_MAXDATALEN (IP_MSS-28)
610	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
611	{
612	unsigned hlen, shlen, s_ip_len;
613	register struct ip *ip;
614	register struct icmp *icp;
615	register struct mbuf *m;
616	int new_m_size = 0;
617	int size = 0;
618
619	LogFlow(("icmp_error: msrc = %lx, msrc_len = %d\n", (long)msrc, msrc ? msrc->m_len : 0));
620	if (msrc != NULL)
621	M_ASSERTPKTHDR(msrc);
622
623	if ( type != ICMP_UNREACH
624	&& type != ICMP_TIMXCEED
625	&& type != ICMP_SOURCEQUENCH)
626	goto end_error;
627
628	/* check msrc */
629	if (!msrc)
630	goto end_error;
631
632	ip = mtod(msrc, struct ip *);
633	LogFunc(("msrc: %RTnaipv4 -> %RTnaipv4\n", ip->ip_src, ip->ip_dst));
634
635	if ( ip->ip_off & IP_OFFMASK
636	&& type != ICMP_SOURCEQUENCH)
637	goto end_error; /* Only reply to fragment 0 */
638
639	shlen = ip->ip_hl << 2;
640	s_ip_len = ip->ip_len;
641	if (ip->ip_p == IPPROTO_ICMP)
642	{
643	icp = (struct icmp )((char )ip + shlen);
644	/*
645	* Assume any unknown ICMP type is an error. This isn't
646	* specified by the RFC, but think about it..
647	*/
648	if (icp->icmp_type>18 \|\| icmp_flush[icp->icmp_type])
649	goto end_error;
650	}
651
652	new_m_size = sizeof(struct ip) + ICMP_MINLEN + msrc->m_len + ICMP_MAXDATALEN;
653	if (new_m_size < MSIZE)
654	size = MCLBYTES;
655	else if (new_m_size < MCLBYTES)
656	size = MCLBYTES;
657	else if(new_m_size < MJUM9BYTES)
658	size = MJUM9BYTES;
659	else if (new_m_size < MJUM16BYTES)
660	size = MJUM16BYTES;
661	else
662	AssertMsgFailed(("Unsupported size"));
663	m = m_getjcl(pData, M_NOWAIT, MT_HEADER, M_PKTHDR, size);
664	if (!m)
665	goto end_error;
666
667	m->m_data += if_maxlinkhdr;
668	m->m_pkthdr.header = mtod(m, void *);
669
670	memcpy(m->m_data, msrc->m_data, msrc->m_len);
671	m->m_len = msrc->m_len; /* copy msrc to m */
672
673	/* make the header of the reply packet */
674	ip = mtod(m, struct ip *);
675	hlen = sizeof(struct ip); /* no options in reply */
676
677	/* fill in icmp */
678	m->m_data += hlen;
679	m->m_len -= hlen;
680
681	icp = mtod(m, struct icmp *);
682
683	if (minsize)
684	s_ip_len = shlen+ICMP_MINLEN; /* return header+8b only */
685	else if (s_ip_len > ICMP_MAXDATALEN) /* maximum size */
686	s_ip_len = ICMP_MAXDATALEN;
687
688	m->m_len = ICMP_MINLEN + s_ip_len; /* 8 bytes ICMP header */
689
690	/* min. size = 8+sizeof(struct ip)+8 */
691
692	icp->icmp_type = type;
693	icp->icmp_code = code;
694	icp->icmp_id = 0;
695	icp->icmp_seq = 0;
696
697	memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
698
699	HTONS(icp->icmp_ip.ip_len);
700	HTONS(icp->icmp_ip.ip_id);
701	HTONS(icp->icmp_ip.ip_off);
702
703	#if DEBUG
704	if (message)
705	{
706	/* DEBUG : append message to ICMP packet */
707	int message_len;
708	message_len = strlen(message);
709	if (message_len > ICMP_MAXDATALEN)
710	message_len = ICMP_MAXDATALEN;
711	m_append(pData, m, message_len, message);
712	}
713	#else
714	NOREF(message);
715	#endif
716
717	icp->icmp_cksum = 0;
718	icp->icmp_cksum = cksum(m, m->m_len);
719
720	/* fill in ip */
721	ip->ip_hl = hlen >> 2;
722	ip->ip_len = m->m_len;
723
724	ip->ip_tos = ((ip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
725
726	ip->ip_ttl = MAXTTL;
727	ip->ip_p = IPPROTO_ICMP;
728	ip->ip_dst = ip->ip_src; /* ip adresses */
729	ip->ip_src = alias_addr;
730
731	/* returns pointer back. */
732	m->m_data -= hlen;
733	m->m_len += hlen;
734	(void) ip_output0(pData, (struct socket *)NULL, m, 1);
735
736	icmpstat.icps_reflect++;
737
738	/* clear source datagramm in positive branch */
739	m_freem(pData, msrc);
740	LogFlowFuncLeave();
741	return;
742
743	end_error:
744
745	/*
746	* clear source datagramm in case if some of requirement haven't been met.
747	*/
748	if (!msrc)
749	m_freem(pData, msrc);
750
751	{
752	static bool fIcmpErrorReported;
753	if (!fIcmpErrorReported)
754	{
755	LogRel(("NAT: error occurred while sending ICMP error message\n"));
756	fIcmpErrorReported = true;
757	}
758	}
759	LogFlowFuncLeave();
760	}
761	#undef ICMP_MAXDATALEN
762
763	/*
764	* Reflect the ip packet back to the source
765	* Note: m isn't duplicated by this method and more delivered to ip_output then.
766	*/
767	void
768	icmp_reflect(PNATState pData, struct mbuf *m)
769	{
770	register struct ip ip = mtod(m, struct ip );
771	int hlen = ip->ip_hl << 2;
772	register struct icmp *icp;
773	LogFlowFunc(("ENTER: m:%p\n", m));
774
775	/*
776	* Send an icmp packet back to the ip level,
777	* after supplying a checksum.
778	*/
779	m->m_data += hlen;
780	m->m_len -= hlen;
781	icp = mtod(m, struct icmp *);
782
783	icp->icmp_cksum = 0;
784	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
785
786	m->m_data -= hlen;
787	m->m_len += hlen;
788
789	(void) ip_output(pData, (struct socket *)NULL, m);
790
791	icmpstat.icps_reflect++;
792	LogFlowFuncLeave();
793	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 40421

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