bootp.c@ 32747

Last change on this file since 32747 was 32747, checked in by vboxsync, 14 years ago
NAT: reduces responsibility of DHCP server about validness of TFTP data (built-in TFTP server do the same check and reports in legacy way).
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 28.0 KB

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1	/* $Id: bootp.c 32747 2010-09-24 08:16:19Z vboxsync $ */
2	/** @file
3	* NAT - BOOTP/DHCP server emulation.
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	* QEMU BOOTP/DHCP server
22	*
23	* Copyright (c) 2004 Fabrice Bellard
24	*
25	* Permission is hereby granted, free of charge, to any person obtaining a copy
26	* of this software and associated documentation files (the "Software"), to deal
27	* in the Software without restriction, including without limitation the rights
28	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
29	* copies of the Software, and to permit persons to whom the Software is
30	* furnished to do so, subject to the following conditions:
31	*
32	* The above copyright notice and this permission notice shall be included in
33	* all copies or substantial portions of the Software.
34	*
35	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
36	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
37	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
38	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
39	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
40	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
41	* THE SOFTWARE.
42	*/
43	#include <slirp.h>
44
45	/** Entry in the table of known DHCP clients. */
46	typedef struct
47	{
48	uint32_t xid;
49	bool allocated;
50	uint8_t macaddr[6];
51	struct in_addr addr;
52	int number;
53	} BOOTPClient;
54	/** Number of DHCP clients supported by NAT. */
55	#define NB_ADDR 16
56
57	#define bootp_clients ((BOOTPClient *)pData->pbootp_clients)
58
59	/* XXX: only DHCP is supported */
60	static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
61
62	static void bootp_reply(PNATState pData, struct mbuf *m0, int offReply, uint16_t flags);
63
64	static uint8_t dhcp_find_option(uint8_t vend, uint8_t tag)
65	{
66	uint8_t *q = vend;
67	uint8_t len;
68	/@todo magic validation /
69	q += 4; /magic/
70	while(*q != RFC1533_END)
71	{
72	if (*q == RFC1533_PAD)
73	continue;
74	if (*q == tag)
75	return q;
76	q++;
77	len = *q;
78	q += 1 + len;
79	}
80	return NULL;
81	}
82
83	static BOOTPClient *bc_alloc_client(PNATState pData)
84	{
85	int i;
86	for (i = 0; i < NB_ADDR; i++)
87	{
88	if (!bootp_clients[i].allocated)
89	{
90	BOOTPClient *bc;
91
92	bc = &bootp_clients[i];
93	memset(bc, 0, sizeof(BOOTPClient));
94	bc->allocated = 1;
95	bc->number = i;
96	return bc;
97	}
98	}
99	return NULL;
100	}
101
102	static BOOTPClient get_new_addr(PNATState pData, struct in_addr paddr)
103	{
104	BOOTPClient *bc;
105	bc = bc_alloc_client(pData);
106	if (!bc)
107	return NULL;
108
109	paddr->s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| (bc->number + START_ADDR));
110	bc->addr.s_addr = paddr->s_addr;
111	return bc;
112	}
113
114	static int release_addr(PNATState pData, struct in_addr *paddr)
115	{
116	unsigned i;
117	for (i = 0; i < NB_ADDR; i++)
118	{
119	if (paddr->s_addr == bootp_clients[i].addr.s_addr)
120	{
121	memset(&bootp_clients[i], 0, sizeof(BOOTPClient));
122	return VINF_SUCCESS;
123	}
124	}
125	return VERR_NOT_FOUND;
126	}
127
128	/*
129	* from RFC 2131 4.3.1
130	* Field DHCPOFFER DHCPACK DHCPNAK
131	* ----- --------- ------- -------
132	* 'op' BOOTREPLY BOOTREPLY BOOTREPLY
133	* 'htype' (From "Assigned Numbers" RFC)
134	* 'hlen' (Hardware address length in octets)
135	* 'hops' 0 0 0
136	* 'xid' 'xid' from client 'xid' from client 'xid' from client
137	* DHCPDISCOVER DHCPREQUEST DHCPREQUEST
138	* message message message
139	* 'secs' 0 0 0
140	* 'ciaddr' 0 'ciaddr' from 0
141	* DHCPREQUEST or 0
142	* 'yiaddr' IP address offered IP address 0
143	* to client assigned to client
144	* 'siaddr' IP address of next IP address of next 0
145	* bootstrap server bootstrap server
146	* 'flags' 'flags' from 'flags' from 'flags' from
147	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
148	* message message message
149	* 'giaddr' 'giaddr' from 'giaddr' from 'giaddr' from
150	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
151	* message message message
152	* 'chaddr' 'chaddr' from 'chaddr' from 'chaddr' from
153	* client DHCPDISCOVER client DHCPREQUEST client DHCPREQUEST
154	* message message message
155	* 'sname' Server host name Server host name (unused)
156	* or options or options
157	* 'file' Client boot file Client boot file (unused)
158	* name or options name or options
159	* 'options' options options
160	*
161	* Option DHCPOFFER DHCPACK DHCPNAK
162	* ------ --------- ------- -------
163	* Requested IP address MUST NOT MUST NOT MUST NOT
164	* IP address lease time MUST MUST (DHCPREQUEST) MUST NOT
165	* MUST NOT (DHCPINFORM)
166	* Use 'file'/'sname' fields MAY MAY MUST NOT
167	* DHCP message type DHCPOFFER DHCPACK DHCPNAK
168	* Parameter request list MUST NOT MUST NOT MUST NOT
169	* Message SHOULD SHOULD SHOULD
170	* Client identifier MUST NOT MUST NOT MAY
171	* Vendor class identifier MAY MAY MAY
172	* Server identifier MUST MUST MUST
173	* Maximum message size MUST NOT MUST NOT MUST NOT
174	* All others MAY MAY MUST NOT
175	*/
176	static BOOTPClient find_addr(PNATState pData, struct in_addr paddr, const uint8_t *macaddr)
177	{
178	int i;
179
180	for (i = 0; i < NB_ADDR; i++)
181	{
182	if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
183	{
184	BOOTPClient *bc;
185
186	bc = &bootp_clients[i];
187	bc->allocated = 1;
188	paddr->s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| (i + START_ADDR));
189	return bc;
190	}
191	}
192	return NULL;
193	}
194
195	static struct mbuf dhcp_create_msg(PNATState pData, struct bootp_t bp, struct mbuf *m, uint8_t type)
196	{
197	struct bootp_t *rbp;
198	struct ethhdr *eh;
199	uint8_t *q;
200
201	eh = mtod(m, struct ethhdr *);
202	memcpy(eh->h_source, bp->bp_hwaddr, ETH_ALEN); /* XXX: if_encap just swap source with dest */
203
204	m->m_data += if_maxlinkhdr; /reserve ether header /
205
206	rbp = mtod(m, struct bootp_t *);
207	memset(rbp, 0, sizeof(struct bootp_t));
208	rbp->bp_op = BOOTP_REPLY;
209	rbp->bp_xid = bp->bp_xid; /* see table 3 of rfc2131*/
210	rbp->bp_flags = bp->bp_flags; /* figure 2 of rfc2131 */
211	rbp->bp_giaddr.s_addr = bp->bp_giaddr.s_addr;
212	#if 0 /check flags/
213	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
214	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
215	#endif
216	rbp->bp_htype = 1;
217	rbp->bp_hlen = 6;
218	memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
219
220	memcpy(rbp->bp_vend, rfc1533_cookie, 4); /* cookie */
221	q = rbp->bp_vend;
222	q += 4;
223	*q++ = RFC2132_MSG_TYPE;
224	*q++ = 1;
225	*q++ = type;
226
227	return m;
228	}
229
230	static int dhcp_do_ack_offer(PNATState pData, struct mbuf m, BOOTPClient bc, int fDhcpRequest)
231	{
232	struct bootp_t *rbp = NULL;
233	uint8_t *q;
234	struct in_addr saddr;
235	int val;
236
237	struct dns_entry *de = NULL;
238	struct dns_domain_entry *dd = NULL;
239	int added = 0;
240	uint8_t *q_dns_header = NULL;
241	uint32_t lease_time = RT_H2N_U32_C(LEASE_TIME);
242	uint32_t netmask = RT_H2N_U32(pData->netmask);
243
244	rbp = mtod(m, struct bootp_t *);
245	q = &rbp->bp_vend[0];
246	q += 7; /* !cookie rfc 2132 + TYPE*/
247
248	/DHCP Offer specific/
249	/*
250	* we're care in built-in tftp server about existence/validness of the boot file.
251	*/
252	if (bootp_filename)
253	RTStrPrintf((char*)rbp->bp_file, sizeof(rbp->bp_file), "%s", bootp_filename);
254
255	Log(("NAT: DHCP: bp_file:%s\n", &rbp->bp_file));
256	/* Address/port of the DHCP server. */
257	rbp->bp_yiaddr = bc->addr; /* Client IP address */
258	Log(("NAT: DHCP: bp_yiaddr:%R[IP4]\n", &rbp->bp_yiaddr));
259	rbp->bp_siaddr = pData->tftp_server; /* Next Server IP address, i.e. TFTP */
260	Log(("NAT: DHCP: bp_siaddr:%R[IP4]\n", &rbp->bp_siaddr));
261	if (fDhcpRequest)
262	{
263	rbp->bp_ciaddr.s_addr = bc->addr.s_addr; /* Client IP address */
264	}
265	#ifndef VBOX_WITH_NAT_SERVICE
266	saddr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
267	#else
268	saddr.s_addr = pData->special_addr.s_addr;
269	#endif
270	Log(("NAT: DHCP: s_addr:%R[IP4]\n", &saddr));
271
272	#define FILL_BOOTP_EXT(q, tag, len, pvalue) \
273	do { \
274	struct bootp_ext be = (struct bootp_ext )(q); \
275	be->bpe_tag = (tag); \
276	be->bpe_len = (len); \
277	memcpy(&be[1], (pvalue), (len)); \
278	(q) = (uint8_t *)(&be[1]) + (len); \
279	}while(0)
280	/* appending another value to tag, calculates len of whole block*/
281	#define FILL_BOOTP_APP(head, q, tag, len, pvalue) \
282	do { \
283	struct bootp_ext be = (struct bootp_ext )(head); \
284	memcpy(q, (pvalue), (len)); \
285	(q) += (len); \
286	Assert(be->bpe_tag == (tag)); \
287	be->bpe_len += (len); \
288	}while(0)
289
290
291	FILL_BOOTP_EXT(q, RFC1533_NETMASK, 4, &netmask);
292	FILL_BOOTP_EXT(q, RFC1533_GATEWAY, 4, &saddr);
293
294	if (pData->fUseDnsProxy \|\| pData->fUseHostResolver)
295	{
296	uint32_t addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_DNS);
297	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &addr);
298	goto skip_dns_servers;
299	}
300
301	if (!TAILQ_EMPTY(&pData->pDnsList))
302	{
303	de = TAILQ_LAST(&pData->pDnsList, dns_list_head);
304	q_dns_header = q;
305	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &de->de_addr.s_addr);
306	}
307
308	TAILQ_FOREACH_REVERSE(de, &pData->pDnsList, dns_list_head, de_list)
309	{
310	if (TAILQ_LAST(&pData->pDnsList, dns_list_head) == de)
311	continue; /* first value with head we've ingected before */
312	FILL_BOOTP_APP(q_dns_header, q, RFC1533_DNS, 4, &de->de_addr.s_addr);
313	}
314
315	skip_dns_servers:
316	if (pData->fPassDomain && !pData->fUseHostResolver)
317	{
318	LIST_FOREACH(dd, &pData->pDomainList, dd_list)
319	{
320
321	if (dd->dd_pszDomain == NULL)
322	continue;
323	/* never meet valid separator here in RFC1533*/
324	if (added != 0)
325	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, ",");
326	else
327	added = 1;
328	val = (int)strlen(dd->dd_pszDomain);
329	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, val, dd->dd_pszDomain);
330	}
331	}
332
333	FILL_BOOTP_EXT(q, RFC2132_LEASE_TIME, 4, &lease_time);
334
335	if (*slirp_hostname)
336	{
337	val = (int)strlen(slirp_hostname);
338	FILL_BOOTP_EXT(q, RFC1533_HOSTNAME, val, slirp_hostname);
339	}
340	slirp_arp_cache_update_or_add(pData, rbp->bp_yiaddr.s_addr, bc->macaddr);
341	return q - rbp->bp_vend; /return offset /
342	}
343
344	static int dhcp_send_nack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
345	{
346	struct bootp_t *rbp;
347	uint8_t *q = NULL;
348	rbp = mtod(m, struct bootp_t *);
349
350	dhcp_create_msg(pData, bp, m, DHCPNAK);
351	return 7;
352	}
353
354	static int dhcp_send_ack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m, int fDhcpRequest)
355	{
356	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
357
358	dhcp_create_msg(pData, bp, m, DHCPACK);
359	offReply = dhcp_do_ack_offer(pData, m, bc, fDhcpRequest);
360	return offReply;
361	}
362
363	static int dhcp_send_offer(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
364	{
365	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
366
367	dhcp_create_msg(pData, bp, m, DHCPOFFER);
368	offReply = dhcp_do_ack_offer(pData, m, bc, /* fDhcpRequest=*/ 0);
369	return offReply;
370	}
371
372	/**
373	* decoding client messages RFC2131 (4.3.6)
374	* ---------------------------------------------------------------------
375	* \| \|INIT-REBOOT \|SELECTING \|RENEWING \|REBINDING \|
376	* ---------------------------------------------------------------------
377	* \|broad/unicast \|broadcast \|broadcast \|unicast \|broadcast \|
378	* \|server-ip \|MUST NOT \|MUST \|MUST NOT \|MUST NOT \|
379	* \|requested-ip \|MUST \|MUST \|MUST NOT \|MUST NOT \|
380	* \|ciaddr \|zero \|zero \|IP address \|IP address\|
381	* ---------------------------------------------------------------------
382	*
383	*/
384
385	enum DHCP_REQUEST_STATES
386	{
387	INIT_REBOOT,
388	SELECTING,
389	RENEWING,
390	REBINDING,
391	NONE
392	};
393
394	static int dhcp_decode_request(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, struct mbuf *m)
395	{
396	BOOTPClient *bc = NULL;
397	struct in_addr daddr;
398	int offReply;
399	uint8_t *req_ip = NULL;
400	uint8_t *server_ip = NULL;
401	uint32_t ui32;
402	enum DHCP_REQUEST_STATES dhcp_stat = NONE;
403
404	/* need to understand which type of request we get */
405	req_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
406	server_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_SRV_ID);
407	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
408
409	if (server_ip != NULL)
410	{
411	/* selecting */
412	if (!bc)
413	{
414	LogRel(("NAT: DHCP no IP was allocated\n"));
415	return -1;
416	}
417
418	dhcp_stat = SELECTING;
419	Assert((bp->bp_ciaddr.s_addr == INADDR_ANY));
420	Assert(((uint32_t )(req_ip + 2) == bc->addr.s_addr)); /the same address as in offer/
421	#if 0
422	/* DSL xid in request differ from offer */
423	Assert((bp->bp_xid == bc->xid));
424	#endif
425	}
426	else
427	{
428	if (req_ip != NULL)
429	{
430	/* init-reboot */
431	dhcp_stat = INIT_REBOOT;
432	}
433	else
434	{
435	/* table 4 of rfc2131 */
436	if (bp->bp_flags & RT_H2N_U16_C(DHCP_FLAGS_B))
437	dhcp_stat = REBINDING;
438	else
439	dhcp_stat = RENEWING;
440	}
441	}
442
443	/?? renewing ??/
444	switch (dhcp_stat)
445	{
446	case RENEWING:
447	Assert((server_ip == NULL && req_ip == NULL && bp->bp_ciaddr.s_addr != INADDR_ANY));
448	if (bc != NULL)
449	{
450	Assert((bc->addr.s_addr == bp->bp_ciaddr.s_addr));
451	/if it already here well just do ack, we aren't aware of dhcp time expiration/
452	}
453	else
454	{
455	if ((bp->bp_ciaddr.s_addr & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
456	{
457	LogRel(("NAT: Client %R[IP4] requested IP -- sending NAK\n", &bp->bp_ciaddr));
458	offReply = dhcp_send_nack(pData, bp, bc, m);
459	return offReply;
460	}
461
462	bc = bc_alloc_client(pData);
463	if (!bc)
464	{
465	LogRel(("NAT: can't alloc address. RENEW has been silently ignored.\n"));
466	return -1;
467	}
468
469	Assert((bp->bp_hlen == ETH_ALEN));
470	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
471	bc->addr.s_addr = bp->bp_ciaddr.s_addr;
472	}
473	break;
474
475	case INIT_REBOOT:
476	Assert(server_ip == NULL);
477	Assert(req_ip != NULL);
478	ui32 = (uint32_t )(req_ip + 2);
479	if ((ui32 & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
480	{
481	LogRel(("NAT: address %R[IP4] has been requested -- sending NAK\n", &ui32));
482	offReply = dhcp_send_nack(pData, bp, bc, m);
483	return offReply;
484	}
485
486	bc = bc_alloc_client(pData);
487	if (!bc)
488	{
489	LogRel(("NAT: can't alloc address. RENEW has been silently ignored\n"));
490	return -1;
491	}
492	Assert((bp->bp_hlen == ETH_ALEN));
493	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
494	bc->addr.s_addr = ui32;
495	break;
496
497	case NONE:
498	Assert((dhcp_stat != NONE));
499	return -1;
500
501	default:
502	break;
503	}
504
505	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
506	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 1);
507	return offReply;
508	}
509
510	static int dhcp_decode_discover(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, int fDhcpDiscover, struct mbuf *m)
511	{
512	BOOTPClient *bc;
513	struct in_addr daddr;
514	int offReply;
515
516	if (fDhcpDiscover)
517	{
518	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
519	if (!bc)
520	{
521	bc = get_new_addr(pData, &daddr);
522	if (!bc)
523	{
524	LogRel(("NAT: DHCP no IP address left\n"));
525	Log(("no address left\n"));
526	return -1;
527	}
528	memcpy(bc->macaddr, bp->bp_hwaddr, 6);
529	}
530
531	bc->xid = bp->bp_xid;
532	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
533	offReply = dhcp_send_offer(pData, bp, bc, m);
534	return offReply;
535	}
536	else
537	{
538	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
539	if (!bc)
540	{
541	LogRel(("NAT: DHCP Inform was ignored no boot client was found\n"));
542	return -1;
543	}
544
545	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
546	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 0);
547	return offReply;
548	}
549
550	return -1;
551	}
552
553	static int dhcp_decode_release(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
554	{
555	int rc = release_addr(pData, &bp->bp_ciaddr);
556	LogRel(("NAT: %s %R[IP4]\n",
557	RT_SUCCESS(rc) ? "DHCP released IP address" : "Ignored DHCP release for IP address",
558	&bp->bp_ciaddr));
559	return 0;
560	}
561	/**
562	* fields for discovering t
563	* Field DHCPDISCOVER DHCPREQUEST DHCPDECLINE,
564	* DHCPINFORM DHCPRELEASE
565	* ----- ------------ ----------- -----------
566	* 'op' BOOTREQUEST BOOTREQUEST BOOTREQUEST
567	* 'htype' (From "Assigned Numbers" RFC)
568	* 'hlen' (Hardware address length in octets)
569	* 'hops' 0 0 0
570	* 'xid' selected by client 'xid' from server selected by
571	* DHCPOFFER message client
572	* 'secs' 0 or seconds since 0 or seconds since 0
573	* DHCP process started DHCP process started
574	* 'flags' Set 'BROADCAST' Set 'BROADCAST' 0
575	* flag if client flag if client
576	* requires broadcast requires broadcast
577	* reply reply
578	* 'ciaddr' 0 (DHCPDISCOVER) 0 or client's 0 (DHCPDECLINE)
579	* client's network address client's network
580	* network address (BOUND/RENEW/REBIND) address
581	* (DHCPINFORM) (DHCPRELEASE)
582	* 'yiaddr' 0 0 0
583	* 'siaddr' 0 0 0
584	* 'giaddr' 0 0 0
585	* 'chaddr' client's hardware client's hardware client's hardware
586	* address address address
587	* 'sname' options, if options, if (unused)
588	* indicated in indicated in
589	* 'sname/file' 'sname/file'
590	* option; otherwise option; otherwise
591	* unused unused
592	* 'file' options, if options, if (unused)
593	* indicated in indicated in
594	* 'sname/file' 'sname/file'
595	* option; otherwise option; otherwise
596	* unused unused
597	* 'options' options options (unused)
598	* Requested IP address MAY MUST (in MUST
599	* (DISCOVER) SELECTING or (DHCPDECLINE),
600	* MUST NOT INIT-REBOOT) MUST NOT
601	* (INFORM) MUST NOT (in (DHCPRELEASE)
602	* BOUND or
603	* RENEWING)
604	* IP address lease time MAY MAY MUST NOT
605	* (DISCOVER)
606	* MUST NOT
607	* (INFORM)
608	* Use 'file'/'sname' fields MAY MAY MAY
609	* DHCP message type DHCPDISCOVER/ DHCPREQUEST DHCPDECLINE/
610	* DHCPINFORM DHCPRELEASE
611	* Client identifier MAY MAY MAY
612	* Vendor class identifier MAY MAY MUST NOT
613	* Server identifier MUST NOT MUST (after MUST
614	* SELECTING)
615	* MUST NOT (after
616	* INIT-REBOOT,
617	* BOUND, RENEWING
618	* or REBINDING)
619	* Parameter request list MAY MAY MUST NOT
620	* Maximum message size MAY MAY MUST NOT
621	* Message SHOULD NOT SHOULD NOT SHOULD
622	* Site-specific MAY MAY MUST NOT
623	* All others MAY MAY MUST NOT
624	*
625	*/
626	static void dhcp_decode(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
627	{
628	const uint8_t p, p_end;
629	int rc;
630	int pmsg_type;
631	struct in_addr req_ip;
632	int fDhcpDiscover = 0;
633	uint8_t *parameter_list = NULL;
634	struct mbuf *m = NULL;
635
636	pmsg_type = 0;
637	p = buf;
638	p_end = buf + size;
639	if (size < 5)
640	return;
641
642	if (memcmp(p, rfc1533_cookie, 4) != 0)
643	return;
644
645	p = dhcp_find_option(bp->bp_vend, RFC2132_MSG_TYPE);
646	Assert(p);
647	if (!p)
648	return;
649	/*
650	* We're going update dns list at least once per DHCP transaction (!not on every operation
651	* within transaction), assuming that transaction can't be longer than 1 min.
652	*/
653	if ( !pData->fUseHostResolver
654	&& ( pData->dnsLastUpdate == 0
655	\|\| curtime - pData->dnsLastUpdate > 60 * 1000)) /* one minute*/
656	{
657	uint8_t i = 2; /* i = 0 - tag, i == 1 - length */
658	parameter_list = dhcp_find_option(&bp->bp_vend[0], RFC2132_PARAM_LIST);
659	for (;parameter_list && i < parameter_list[1]; ++i)
660	{
661	if (parameter_list[i] == RFC1533_DNS)
662	{
663	slirp_release_dns_list(pData);
664	slirp_init_dns_list(pData);
665	pData->dnsLastUpdate = curtime;
666	break;
667	}
668	}
669	}
670
671	m = m_getcl(pData, M_DONTWAIT, MT_HEADER, M_PKTHDR);
672	if (!m)
673	{
674	LogRel(("NAT: can't alocate memory for response!\n"));
675	return;
676	}
677
678	switch (*(p+2))
679	{
680	case DHCPDISCOVER:
681	fDhcpDiscover = 1;
682	/* fall through */
683	case DHCPINFORM:
684	rc = dhcp_decode_discover(pData, bp, buf, size, fDhcpDiscover, m);
685	if (rc > 0)
686	goto reply;
687	break;
688
689	case DHCPREQUEST:
690	rc = dhcp_decode_request(pData, bp, buf, size, m);
691	if (rc > 0)
692	goto reply;
693	break;
694
695	case DHCPRELEASE:
696	rc = dhcp_decode_release(pData, bp, buf, size);
697	/* no reply required */
698	break;
699
700	case DHCPDECLINE:
701	p = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
702	req_ip.s_addr = (uint32_t )(p + 2);
703	rc = bootp_cache_lookup_ether_by_ip(pData, req_ip.s_addr, NULL);
704	if (RT_FAILURE(rc))
705	{
706	/* Not registered */
707	BOOTPClient *bc;
708	bc = bc_alloc_client(pData);
709	Assert(bc);
710	bc->addr.s_addr = req_ip.s_addr;
711	slirp_arp_who_has(pData, bc->addr.s_addr);
712	LogRel(("NAT: %R[IP4] has been already registered\n", &req_ip));
713	}
714	/* no response required */
715	break;
716
717	default:
718	AssertMsgFailed(("unsupported DHCP message type"));
719	}
720	/* silently ignore */
721	m_freem(pData, m);
722	return;
723
724	reply:
725	bootp_reply(pData, m, rc, bp->bp_flags);
726	}
727
728	static void bootp_reply(PNATState pData, struct mbuf *m, int offReply, uint16_t flags)
729	{
730	struct sockaddr_in saddr, daddr;
731	struct bootp_t *rbp = NULL;
732	uint8_t *q = NULL;
733	int nack;
734	rbp = mtod(m, struct bootp_t *);
735	Assert((m));
736	Assert((rbp));
737	q = rbp->bp_vend;
738	nack = (q[6] == DHCPNAK);
739	q += offReply;
740
741	#ifndef VBOX_WITH_NAT_SERVICE
742	saddr.sin_addr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
743	#else
744	saddr.sin_addr.s_addr = pData->special_addr.s_addr;
745	#endif
746
747	FILL_BOOTP_EXT(q, RFC2132_SRV_ID, 4, &saddr.sin_addr);
748
749	q++ = RFC1533_END; / end of message */
750
751	m->m_pkthdr.header = mtod(m, void *);
752	m->m_len = sizeof(struct bootp_t)
753	- sizeof(struct ip)
754	- sizeof(struct udphdr);
755	m->m_data += sizeof(struct udphdr)
756	+ sizeof(struct ip);
757	if ( (flags & RT_H2N_U16_C(DHCP_FLAGS_B))
758	\|\| nack != 0)
759	daddr.sin_addr.s_addr = INADDR_BROADCAST;
760	else
761	daddr.sin_addr.s_addr = rbp->bp_yiaddr.s_addr; /unicast requested by client/
762	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
763	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
764	udp_output2(pData, NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
765	}
766
767	void bootp_input(PNATState pData, struct mbuf *m)
768	{
769	struct bootp_t bp = mtod(m, struct bootp_t );
770
771	if (bp->bp_op == BOOTP_REQUEST)
772	dhcp_decode(pData, bp, bp->bp_vend, DHCP_OPT_LEN);
773	}
774
775	int bootp_cache_lookup_ip_by_ether(PNATState pData,const uint8_t* ether, uint32_t *pip)
776	{
777	int i;
778
779	if (!ether \|\| !pip)
780	return VERR_INVALID_PARAMETER;
781
782	for (i = 0; i < NB_ADDR; i++)
783	{
784	if ( bootp_clients[i].allocated
785	&& memcmp(bootp_clients[i].macaddr, ether, ETH_ALEN) == 0)
786	{
787	*pip = bootp_clients[i].addr.s_addr;
788	return VINF_SUCCESS;
789	}
790	}
791
792	*pip = INADDR_ANY;
793	return VERR_NOT_FOUND;
794	}
795
796	int bootp_cache_lookup_ether_by_ip(PNATState pData, uint32_t ip, uint8_t *ether)
797	{
798	int i;
799	for (i = 0; i < NB_ADDR; i++)
800	{
801	if ( bootp_clients[i].allocated
802	&& ip == bootp_clients[i].addr.s_addr)
803	{
804	if (ether != NULL)
805	memcpy(ether, bootp_clients[i].macaddr, ETH_ALEN);
806	return VINF_SUCCESS;
807	}
808	}
809
810	return VERR_NOT_FOUND;
811	}
812
813	/*
814	* Initialize dhcp server
815	* @returns 0 - if initialization is ok, non-zero otherwise
816	*/
817	int bootp_dhcp_init(PNATState pData)
818	{
819	pData->pbootp_clients = RTMemAllocZ(sizeof(BOOTPClient) * NB_ADDR);
820	if (!pData->pbootp_clients)
821	return VERR_NO_MEMORY;
822
823	return VINF_SUCCESS;
824	}
825
826	int bootp_dhcp_fini(PNATState pData)
827	{
828	if (pData->pbootp_clients != NULL)
829	RTMemFree(pData->pbootp_clients);
830
831	return VINF_SUCCESS;
832	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/bootp.c@ 32747

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