ip_icmp.c@ 30363

Last change on this file since 30363 was 30363, checked in by vboxsync, 14 years ago
NAT: more comments + cosmetics
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File size: 23.6 KB

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1	/* $Id: ip_icmp.c 30363 2010-06-22 11:21:22Z 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	#ifdef RT_OS_WINDOWS
64	# define ICMP_SEND_ECHO(event, routine, addr, data, datasize, ipopt) \
65	IcmpSendEcho2(pData->icmp_socket.sh, (event), NULL, NULL, (addr), (data), (datasize), \
66	(ipopt), pData->pvIcmpBuffer, pData->szIcmpBuffer, 1)
67	#endif /* RT_OS_WINDOWS */
68
69	/* The message sent when emulating PING */
70	/* Be nice and tell them it's just a psuedo-ping packet */
71	static const char icmp_ping_msg[] = "This is a psuedo-PING packet used by Slirp to emulate ICMP ECHO-REQUEST packets.\n";
72
73	/* list of actions for icmp_error() on RX of an icmp message */
74	static const int icmp_flush[19] =
75	{
76	/* ECHO REPLY (0) */ 0,
77	1,
78	1,
79	/* DEST UNREACH (3) */ 1,
80	/* SOURCE QUENCH (4)*/ 1,
81	/* REDIRECT (5) */ 1,
82	1,
83	1,
84	/* ECHO (8) */ 0,
85	/* ROUTERADVERT (9) */ 1,
86	/* ROUTERSOLICIT (10) */ 1,
87	/* TIME EXCEEDED (11) */ 1,
88	/* PARAMETER PROBLEM (12) */ 1,
89	/* TIMESTAMP (13) */ 0,
90	/* TIMESTAMP REPLY (14) */ 0,
91	/* INFO (15) */ 0,
92	/* INFO REPLY (16) */ 0,
93	/* ADDR MASK (17) */ 0,
94	/* ADDR MASK REPLY (18) */ 0
95	};
96
97	int
98	icmp_init(PNATState pData)
99	{
100	pData->icmp_socket.so_type = IPPROTO_ICMP;
101	pData->icmp_socket.so_state = SS_ISFCONNECTED;
102	#ifndef RT_OS_WINDOWS
103	# ifndef RT_OS_DARWIN
104	pData->icmp_socket.s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
105	# else /* !RT_OS_DARWIN */
106	pData->icmp_socket.s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
107	# endif /* RT_OS_DARWIN */
108	if (pData->icmp_socket.s == -1)
109	{
110	int rc = RTErrConvertFromErrno(errno);
111	LogRel(("NAT: ICMP/ping not available (could not open ICMP socket, error %Rrc)\n", rc));
112	return 1;
113	}
114	fd_nonblock(pData->icmp_socket.s);
115	NSOCK_INC();
116	#else /* RT_OS_WINDOWS */
117	pData->hmIcmpLibrary = LoadLibrary("Iphlpapi.dll");
118	if (pData->hmIcmpLibrary != NULL)
119	{
120	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
121	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
122	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
123	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
124	pData->pfGetAdaptersAddresses = (ULONG (WINAPI *)(ULONG, ULONG, PVOID, PIP_ADAPTER_ADDRESSES, PULONG))
125	GetProcAddress(pData->hmIcmpLibrary, "GetAdaptersAddresses");
126	if (pData->pfGetAdaptersAddresses == NULL)
127	{
128	LogRel(("NAT: Can't find GetAdapterAddresses in Iphlpapi.dll"));
129	}
130	}
131
132	if (pData->pfIcmpParseReplies == NULL)
133	{
134	if(pData->pfGetAdaptersAddresses == NULL)
135	FreeLibrary(pData->hmIcmpLibrary);
136	pData->hmIcmpLibrary = LoadLibrary("Icmp.dll");
137	if (pData->hmIcmpLibrary == NULL)
138	{
139	LogRel(("NAT: Icmp.dll could not be loaded\n"));
140	return 1;
141	}
142	pData->pfIcmpParseReplies = (long (WINAPI )(void , long))
143	GetProcAddress(pData->hmIcmpLibrary, "IcmpParseReplies");
144	pData->pfIcmpCloseHandle = (BOOL (WINAPI *)(HANDLE))
145	GetProcAddress(pData->hmIcmpLibrary, "IcmpCloseHandle");
146	}
147	if (pData->pfIcmpParseReplies == NULL)
148	{
149	LogRel(("NAT: Can't find IcmpParseReplies symbol\n"));
150	FreeLibrary(pData->hmIcmpLibrary);
151	return 1;
152	}
153	if (pData->pfIcmpCloseHandle == NULL)
154	{
155	LogRel(("NAT: Can't find IcmpCloseHandle symbol\n"));
156	FreeLibrary(pData->hmIcmpLibrary);
157	return 1;
158	}
159	pData->icmp_socket.sh = IcmpCreateFile();
160	pData->phEvents[VBOX_ICMP_EVENT_INDEX] = CreateEvent(NULL, FALSE, FALSE, NULL);
161	pData->szIcmpBuffer = sizeof(ICMP_ECHO_REPLY) * 10;
162	pData->pvIcmpBuffer = RTMemAlloc(pData->szIcmpBuffer);
163	#endif /* RT_OS_WINDOWS */
164	LIST_INIT(&pData->icmp_msg_head);
165	return 0;
166	}
167
168	/*
169	* ip here is ip header + 64bytes readed from ICMP packet
170	*/
171	struct icmp_msg *
172	icmp_find_original_mbuf(PNATState pData, struct ip *ip)
173	{
174	struct mbuf *m0;
175	struct ip *ip0;
176	struct icmp icp, icp0;
177	struct icmp_msg *icm = NULL;
178	int found = 0;
179	struct udphdr *udp;
180	struct tcphdr *tcp;
181	struct socket *head_socket = NULL;
182	struct socket *last_socket = NULL;
183	struct socket *so = NULL;
184	struct in_addr laddr, faddr;
185	u_short lport, fport;
186
187	laddr.s_addr = ~0;
188	faddr.s_addr = ~0;
189
190	lport = ~0;
191	fport = ~0;
192
193
194	Log(("%s: processing (proto:%d)\n", __FUNCTION__, ip->ip_p));
195	switch (ip->ip_p)
196	{
197	case IPPROTO_ICMP:
198	icp = (struct icmp )((char )ip + (ip->ip_hl << 2));
199	LIST_FOREACH(icm, &pData->icmp_msg_head, im_list)
200	{
201	m0 = icm->im_m;
202	ip0 = mtod(m0, struct ip *);
203	if (ip0->ip_p != IPPROTO_ICMP)
204	{
205	/* try next item */
206	continue;
207	}
208	icp0 = (struct icmp )((char )ip0 + (ip0->ip_hl << 2));
209	/*
210	* IP could pointer to ICMP_REPLY datagram (1)
211	* or pointer IP header in ICMP payload in case of
212	* ICMP_TIMXCEED or ICMP_UNREACH (2)
213	*
214	* if (1) and then ICMP (type should be ICMP_ECHOREPLY) and we need check that
215	* IP.IP_SRC == IP0.IP_DST received datagramm comes from destination.
216	*
217	* if (2) then check that payload ICMP has got type ICMP_ECHO and
218	* IP.IP_DST == IP0.IP_DST destination of returned datagram is the same as
219	* one was sent.
220	*/
221	if ( ( (icp->icmp_type != ICMP_ECHO && ip->ip_src.s_addr == ip0->ip_dst.s_addr)
222	\|\| (icp->icmp_type == ICMP_ECHO && ip->ip_dst.s_addr == ip0->ip_dst.s_addr))
223	&& icp->icmp_id == icp0->icmp_id
224	&& icp->icmp_seq == icp0->icmp_seq)
225	{
226	found = 1;
227	Log(("Have found %R[natsock]\n", icm->im_so));
228	break;
229	}
230	Log(("Have found nothing\n"));
231	}
232	break;
233
234	/*
235	* for TCP and UDP logic little bit reverted, we try to find the HOST socket
236	* from which the IP package has been sent.
237	*/
238	case IPPROTO_UDP:
239	head_socket = &udb;
240	udp = (struct udphdr )((char )ip + (ip->ip_hl << 2));
241	faddr.s_addr = ip->ip_dst.s_addr;
242	fport = udp->uh_dport;
243	laddr.s_addr = ip->ip_src.s_addr;
244	lport = udp->uh_sport;
245	last_socket = udp_last_so;
246	/* fall through */
247
248	case IPPROTO_TCP:
249	if (head_socket == NULL)
250	{
251	tcp = (struct tcphdr )((char )ip + (ip->ip_hl << 2));
252	head_socket = &tcb; /* head_socket could be initialized with udb*/
253	faddr.s_addr = ip->ip_dst.s_addr;
254	fport = tcp->th_dport;
255	laddr.s_addr = ip->ip_src.s_addr;
256	lport = tcp->th_sport;
257	last_socket = tcp_last_so;
258	}
259	/* check last socket first */
260	if ( last_socket->so_faddr.s_addr == faddr.s_addr
261	&& last_socket->so_fport == fport
262	&& last_socket->so_hlport == lport)
263	{
264	found = 1;
265	so = last_socket;
266	goto sofound;
267	}
268	for (so = head_socket->so_prev; so != head_socket; so = so->so_prev)
269	{
270	/* Should be reaplaced by hash here */
271	Log(("trying:%R[natsock] against %R[IP4]:%d lport=%d hlport=%d\n", so, &faddr, fport, lport, so->so_hlport));
272	if ( so->so_faddr.s_addr == faddr.s_addr
273	&& so->so_fport == fport
274	&& so->so_hlport == lport)
275	{
276	found = 1;
277	break;
278	}
279	}
280	break;
281
282	default:
283	LogRel(("%s:ICMP: unsupported protocol(%d)\n", __FUNCTION__, ip->ip_p));
284	}
285	sofound:
286	if (found == 1 && icm == NULL)
287	{
288	if (so->so_state == SS_NOFDREF)
289	{
290	/* socket is shutdowning we've already sent ICMP on it.*/
291	LogRel(("NAT: Received icmp on shutdowning socket (probably corresponding ICMP socket has been already sent)\n"));
292	return NULL;
293	}
294	icm = RTMemAlloc(sizeof(struct icmp_msg));
295	icm->im_m = so->so_m;
296	icm->im_so = so;
297	found = 1;
298	Log(("hit:%R[natsock]\n", so));
299	/*XXX: this storage not very long,
300	* better add flag if it should removed from lis
301	*/
302	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
303	return (icm);
304	}
305	if (found == 1)
306	return icm;
307
308	return NULL;
309	}
310
311	static int
312	icmp_attach(PNATState pData, struct mbuf *m)
313	{
314	struct icmp_msg *icm;
315	struct ip *ip;
316	ip = mtod(m, struct ip *);
317	Assert(ip->ip_p == IPPROTO_ICMP);
318	icm = RTMemAlloc(sizeof(struct icmp_msg));
319	icm->im_m = m;
320	icm->im_so = m->m_so;
321	LIST_INSERT_HEAD(&pData->icmp_msg_head, icm, im_list);
322	return 0;
323	}
324
325	/*
326	* Process a received ICMP message.
327	*/
328	void
329	icmp_input(PNATState pData, struct mbuf *m, int hlen)
330	{
331	register struct icmp *icp;
332	register struct ip ip = mtod(m, struct ip );
333	int icmplen = ip->ip_len;
334	int status;
335	uint32_t dst;
336	#if !defined(RT_OS_WINDOWS)
337	int ttl;
338	#endif
339
340	/* int code; */
341
342	DEBUG_CALL("icmp_input");
343	DEBUG_ARG("m = %lx", (long )m);
344	DEBUG_ARG("m_len = %d", m ? m->m_len : 0);
345
346	icmpstat.icps_received++;
347
348	/*
349	* Locate icmp structure in mbuf, and check
350	* that its not corrupted and of at least minimum length.
351	*/
352	if (icmplen < ICMP_MINLEN)
353	{
354	/* min 8 bytes payload */
355	icmpstat.icps_tooshort++;
356	freeit:
357	m_freem(pData, m);
358	goto end_error;
359	}
360
361	m->m_len -= hlen;
362	m->m_data += hlen;
363	if (m->m_next != NULL)
364	{
365	char *buf = RTMemAlloc(icmplen);
366	m_copydata(m, 0, icmplen, buf);
367	icp = (struct icmp *)buf;
368	}
369	else
370	{
371	icp = mtod(m, struct icmp *);
372	}
373	if (cksum(m, icmplen))
374	{
375	icmpstat.icps_checksum++;
376	goto freeit;
377	}
378	m->m_len += hlen;
379	m->m_data -= hlen;
380
381	/* icmpstat.icps_inhist[icp->icmp_type]++; */
382	/* code = icp->icmp_code; */
383
384	DEBUG_ARG("icmp_type = %d", icp->icmp_type);
385	switch (icp->icmp_type)
386	{
387	case ICMP_ECHO:
388	ip->ip_len += hlen; /* since ip_input subtracts this */
389	dst = ip->ip_dst.s_addr;
390	if (dst == alias_addr.s_addr)
391	{
392	icp->icmp_type = ICMP_ECHOREPLY;
393	ip->ip_dst.s_addr = ip->ip_src.s_addr;
394	ip->ip_src.s_addr = dst;
395	icmp_reflect(pData, m);
396	}
397	else
398	{
399	struct sockaddr_in addr;
400	#ifdef RT_OS_WINDOWS
401	IP_OPTION_INFORMATION ipopt;
402	int error;
403	#endif
404	addr.sin_family = AF_INET;
405	if ((ip->ip_dst.s_addr & RT_H2N_U32(pData->netmask)) == pData->special_addr.s_addr)
406	{
407	/* It's an alias */
408	switch (RT_N2H_U32(ip->ip_dst.s_addr) & ~pData->netmask)
409	{
410	case CTL_DNS:
411	case CTL_ALIAS:
412	default:
413	addr.sin_addr = loopback_addr;
414	break;
415	}
416	}
417	else
418	addr.sin_addr.s_addr = ip->ip_dst.s_addr;
419	#ifndef RT_OS_WINDOWS
420	if (pData->icmp_socket.s != -1)
421	{
422	ssize_t rc;
423	m->m_so = &pData->icmp_socket;
424	icmp_attach(pData, m);
425	ttl = ip->ip_ttl;
426	Log(("NAT/ICMP: try to set TTL(%d)\n", ttl));
427	status = setsockopt(pData->icmp_socket.s, IPPROTO_IP, IP_TTL,
428	(void *)&ttl, sizeof(ttl));
429	if (status < 0)
430	LogRel(("NAT: Error (%s) occurred while setting TTL attribute of IP packet\n",
431	strerror(errno)));
432	rc = sendto(pData->icmp_socket.s, icp, icmplen, 0,
433	(struct sockaddr *)&addr, sizeof(addr));
434	if (rc < 0)
435	{
436	LogRel((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
437	errno, strerror(errno)));
438	icmp_error(pData, m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
439	}
440	}
441	else
442	{
443	/*
444	* We're freeing the ICMP message, which unable sent or process.
445	* That behavior described in rfc 793, we shouldn't notify sender about
446	* fail of processing it's ICMP packets
447	*/
448	m_free(pData, m);
449	return;
450	}
451	#else /* RT_OS_WINDOWS */
452	icmp_attach(pData, m);
453	pData->icmp_socket.so_laddr.s_addr = ip->ip_src.s_addr; /* XXX: hack*/
454	pData->icmp_socket.so_icmp_id = icp->icmp_id;
455	pData->icmp_socket.so_icmp_seq = icp->icmp_seq;
456	m->m_so = &pData->icmp_socket;
457	memset(&ipopt, 0, sizeof(IP_OPTION_INFORMATION));
458	ipopt.Ttl = ip->ip_ttl;
459	status = ICMP_SEND_ECHO(pData->phEvents[VBOX_ICMP_EVENT_INDEX], notify_slirp, addr.sin_addr.s_addr,
460	icp->icmp_data, icmplen - ICMP_MINLEN, &ipopt);
461	if (status == 0 && (error = GetLastError()) != ERROR_IO_PENDING)
462	{
463	error = GetLastError();
464	LogRel(("NAT: Error (%d) occurred while sending ICMP (", error));
465	switch (error)
466	{
467	case ERROR_INVALID_PARAMETER:
468	LogRel(("icmp_socket:%lx is invalid)\n", pData->icmp_socket.s));
469	break;
470	case ERROR_NOT_SUPPORTED:
471	LogRel(("operation is unsupported)\n"));
472	break;
473	case ERROR_NOT_ENOUGH_MEMORY:
474	LogRel(("OOM!!!)\n"));
475	break;
476	case IP_BUF_TOO_SMALL:
477	LogRel(("Buffer too small)\n"));
478	break;
479	default:
480	LogRel(("Other error!!!)\n"));
481	break;
482	}
483	}
484	#endif /* RT_OS_WINDOWS */
485	} /* if ip->ip_dst.s_addr == alias_addr.s_addr */
486	break;
487	case ICMP_UNREACH:
488	/* XXX? report error? close socket? */
489	case ICMP_TIMXCEED:
490	case ICMP_PARAMPROB:
491	case ICMP_SOURCEQUENCH:
492	case ICMP_TSTAMP:
493	case ICMP_MASKREQ:
494	case ICMP_REDIRECT:
495	icmpstat.icps_notsupp++;
496	m_freem(pData, m);
497	break;
498
499	default:
500	icmpstat.icps_badtype++;
501	m_freem(pData, m);
502	} /* switch */
503	if (m->m_next != NULL && icp != NULL)
504	RTMemFree(icp);
505
506	end_error:
507	/* m is m_free()'d xor put in a socket xor or given to ip_send */
508	;
509	}
510
511
512	/**
513	* Send an ICMP message in response to a situation
514	*
515	* RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. MAY send more (we do).
516	* MUST NOT change this header information.
517	* MUST NOT reply to a multicast/broadcast IP address.
518	* MUST NOT reply to a multicast/broadcast MAC address.
519	* MUST reply to only the first fragment.
520	*/
521	/*
522	* Send ICMP_UNREACH back to the source regarding msrc.
523	* mbuf *msrc is used as a template, but is NOT m_free()'d.
524	* It is reported as the bad ip packet. The header should
525	* be fully correct and in host byte order.
526	* ICMP fragmentation is illegal. All machines must accept 576 bytes in one
527	* packet. The maximum payload is 576-20(ip hdr)-8(icmp hdr)=548
528	*
529	* @note This function will free msrc!
530	*/
531
532	#define ICMP_MAXDATALEN (IP_MSS-28)
533	void icmp_error(PNATState pData, struct mbuf msrc, u_char type, u_char code, int minsize, const char message)
534	{
535	unsigned hlen, shlen, s_ip_len;
536	register struct ip *ip;
537	register struct icmp *icp;
538	register struct mbuf *m;
539	int new_m_size = 0;
540	int size = 0;
541
542	DEBUG_CALL("icmp_error");
543	DEBUG_ARG("msrc = %lx", (long )msrc);
544	DEBUG_ARG("msrc_len = %d", msrc ? msrc->m_len : 0);
545	if (msrc != NULL)
546	M_ASSERTPKTHDR(msrc);
547
548	if ( type != ICMP_UNREACH
549	&& type != ICMP_TIMXCEED
550	&& type != ICMP_SOURCEQUENCH)
551	goto end_error;
552
553	/* check msrc */
554	if (!msrc)
555	goto end_error;
556
557	ip = mtod(msrc, struct ip *);
558	#if DEBUG
559	{
560	char bufa[20], bufb[20];
561	strcpy(bufa, inet_ntoa(ip->ip_src));
562	strcpy(bufb, inet_ntoa(ip->ip_dst));
563	DEBUG_MISC((dfd, " %.16s to %.16s\n", bufa, bufb));
564	}
565	#endif
566	if ( ip->ip_off & IP_OFFMASK
567	&& type != ICMP_SOURCEQUENCH)
568	goto end_error; /* Only reply to fragment 0 */
569
570	shlen = ip->ip_hl << 2;
571	s_ip_len = ip->ip_len;
572	if (ip->ip_p == IPPROTO_ICMP)
573	{
574	icp = (struct icmp )((char )ip + shlen);
575	/*
576	* Assume any unknown ICMP type is an error. This isn't
577	* specified by the RFC, but think about it..
578	*/
579	if (icp->icmp_type>18 \|\| icmp_flush[icp->icmp_type])
580	goto end_error;
581	}
582
583	new_m_size = sizeof(struct ip) + ICMP_MINLEN + msrc->m_len + ICMP_MAXDATALEN;
584	if (new_m_size < MSIZE)
585	{
586	size = MCLBYTES;
587	}
588	else if (new_m_size < MCLBYTES)
589	{
590	size = MCLBYTES;
591	}
592	else if(new_m_size < MJUM9BYTES)
593	{
594	size = MJUM9BYTES;
595	}
596	else if (new_m_size < MJUM16BYTES)
597	{
598	size = MJUM16BYTES;
599	}
600	else
601	{
602	AssertMsgFailed(("Unsupported size"));
603	}
604	m = m_getjcl(pData, M_NOWAIT, MT_HEADER, M_PKTHDR, size);
605	if (!m)
606	goto end_error;
607
608	m->m_data += if_maxlinkhdr;
609	m->m_pkthdr.header = mtod(m, void *);
610
611	memcpy(m->m_data, msrc->m_data, msrc->m_len);
612	m->m_len = msrc->m_len; /* copy msrc to m */
613
614	/* make the header of the reply packet */
615	ip = mtod(m, struct ip *);
616	hlen = sizeof(struct ip ); /* no options in reply */
617
618	/* fill in icmp */
619	m->m_data += hlen;
620	m->m_len -= hlen;
621
622	icp = mtod(m, struct icmp *);
623
624	if (minsize)
625	s_ip_len = shlen+ICMP_MINLEN; /* return header+8b only */
626	else if (s_ip_len > ICMP_MAXDATALEN) /* maximum size */
627	s_ip_len = ICMP_MAXDATALEN;
628
629	m->m_len = ICMP_MINLEN + s_ip_len; /* 8 bytes ICMP header */
630
631	/* min. size = 8+sizeof(struct ip)+8 */
632
633	icp->icmp_type = type;
634	icp->icmp_code = code;
635	icp->icmp_id = 0;
636	icp->icmp_seq = 0;
637
638	memcpy(&icp->icmp_ip, msrc->m_data, s_ip_len); /* report the ip packet */
639
640	HTONS(icp->icmp_ip.ip_len);
641	HTONS(icp->icmp_ip.ip_id);
642	HTONS(icp->icmp_ip.ip_off);
643
644	#if DEBUG
645	if (message)
646	{
647	/* DEBUG : append message to ICMP packet */
648	int message_len;
649	char *cpnt;
650	message_len = strlen(message);
651	if (message_len > ICMP_MAXDATALEN)
652	message_len = ICMP_MAXDATALEN;
653	cpnt = (char *)m->m_data+m->m_len;
654	m_append(pData, m, message_len, message);
655	}
656	#endif
657
658	icp->icmp_cksum = 0;
659	icp->icmp_cksum = cksum(m, m->m_len);
660
661	/* fill in ip */
662	ip->ip_hl = hlen >> 2;
663	ip->ip_len = m->m_len;
664
665	ip->ip_tos = ((ip->ip_tos & 0x1E) \| 0xC0); /* high priority for errors */
666
667	ip->ip_ttl = MAXTTL;
668	ip->ip_p = IPPROTO_ICMP;
669	ip->ip_dst = ip->ip_src; /* ip adresses */
670	ip->ip_src = alias_addr;
671
672	(void ) ip_output0(pData, (struct socket *)NULL, m, 1);
673
674	icmpstat.icps_reflect++;
675
676	return;
677
678	end_error_free_m:
679	m_freem(pData, m);
680
681	end_error:
682	LogRel(("NAT: error occurred while sending ICMP error message\n"));
683	}
684	#undef ICMP_MAXDATALEN
685
686	/*
687	* Reflect the ip packet back to the source
688	*/
689	void
690	icmp_reflect(PNATState pData, struct mbuf *m)
691	{
692	register struct ip ip = mtod(m, struct ip );
693	int hlen = ip->ip_hl << 2;
694	int optlen = hlen - sizeof(struct ip );
695	register struct icmp *icp;
696
697	/*
698	* Send an icmp packet back to the ip level,
699	* after supplying a checksum.
700	*/
701	m->m_data += hlen;
702	m->m_len -= hlen;
703	icp = mtod(m, struct icmp *);
704
705	icp->icmp_cksum = 0;
706	icp->icmp_cksum = cksum(m, ip->ip_len - hlen);
707
708	m->m_data -= hlen;
709	m->m_len += hlen;
710
711	(void ) ip_output(pData, (struct socket *)NULL, m);
712
713	icmpstat.icps_reflect++;
714	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/ip_icmp.c@ 30363

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