bootp.c@ 30016

Last change on this file since 30016 was 30016, checked in by vboxsync, 14 years ago
NAT: clean up.
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File size: 28.2 KB

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1	/* $Id: bootp.c 30016 2010-06-03 18:31:14Z 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	if ( tftp_prefix
250	&& RTDirExists(tftp_prefix)
251	&& bootp_filename)
252	RTStrPrintf((char*)rbp->bp_file, sizeof(rbp->bp_file), "%s", bootp_filename);
253
254	Log(("NAT: DHCP: bp_file:%s\n", &rbp->bp_file));
255	/* Address/port of the DHCP server. */
256	rbp->bp_yiaddr = bc->addr; /* Client IP address */
257	Log(("NAT: DHCP: bp_yiaddr:%R[IP4]\n", &rbp->bp_yiaddr));
258	rbp->bp_siaddr = pData->tftp_server; /* Next Server IP address, i.e. TFTP */
259	Log(("NAT: DHCP: bp_siaddr:%R[IP4]\n", &rbp->bp_siaddr));
260	if (fDhcpRequest)
261	{
262	rbp->bp_ciaddr.s_addr = bc->addr.s_addr; /* Client IP address */
263	}
264	#ifndef VBOX_WITH_NAT_SERVICE
265	saddr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
266	#else
267	saddr.s_addr = pData->special_addr.s_addr;
268	#endif
269	Log(("NAT: DHCP: s_addr:%R[IP4]\n", &saddr));
270
271	#define FILL_BOOTP_EXT(q, tag, len, pvalue) \
272	do { \
273	struct bootp_ext be = (struct bootp_ext )(q); \
274	be->bpe_tag = (tag); \
275	be->bpe_len = (len); \
276	memcpy(&be[1], (pvalue), (len)); \
277	(q) = (uint8_t *)(&be[1]) + (len); \
278	}while(0)
279	/* appending another value to tag, calculates len of whole block*/
280	#define FILL_BOOTP_APP(head, q, tag, len, pvalue) \
281	do { \
282	struct bootp_ext be = (struct bootp_ext )(head); \
283	memcpy(q, (pvalue), (len)); \
284	(q) += (len); \
285	Assert(be->bpe_tag == (tag)); \
286	be->bpe_len += (len); \
287	}while(0)
288
289
290	FILL_BOOTP_EXT(q, RFC1533_NETMASK, 4, &netmask);
291	FILL_BOOTP_EXT(q, RFC1533_GATEWAY, 4, &saddr);
292
293	if (pData->fUseDnsProxy \|\| pData->fUseHostResolver)
294	{
295	uint32_t addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_DNS);
296	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &addr);
297	goto skip_dns_servers;
298	}
299
300	if (!TAILQ_EMPTY(&pData->pDnsList))
301	{
302	de = TAILQ_LAST(&pData->pDnsList, dns_list_head);
303	q_dns_header = q;
304	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &de->de_addr.s_addr);
305	}
306
307	TAILQ_FOREACH_REVERSE(de, &pData->pDnsList, dns_list_head, de_list)
308	{
309	if (TAILQ_LAST(&pData->pDnsList, dns_list_head) == de)
310	continue; /* first value with head we've ingected before */
311	FILL_BOOTP_APP(q_dns_header, q, RFC1533_DNS, 4, &de->de_addr.s_addr);
312	}
313
314	skip_dns_servers:
315	if (LIST_EMPTY(&pData->pDomainList))
316	{
317	/* Microsoft dhcp client doen't like domain-less dhcp and trimmed packets*/
318	/* dhcpcd client very sad if no domain name is passed */
319	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, " ");
320	}
321	if (pData->fPassDomain && !pData->fUseHostResolver)
322	{
323	LIST_FOREACH(dd, &pData->pDomainList, dd_list)
324	{
325
326	if (dd->dd_pszDomain == NULL)
327	continue;
328	/* never meet valid separator here in RFC1533*/
329	if (added != 0)
330	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, ",");
331	else
332	added = 1;
333	val = (int)strlen(dd->dd_pszDomain);
334	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, val, dd->dd_pszDomain);
335	}
336	}
337
338	FILL_BOOTP_EXT(q, RFC2132_LEASE_TIME, 4, &lease_time);
339
340	if (*slirp_hostname)
341	{
342	val = (int)strlen(slirp_hostname);
343	FILL_BOOTP_EXT(q, RFC1533_HOSTNAME, val, slirp_hostname);
344	}
345	slirp_arp_cache_update_or_add(pData, rbp->bp_yiaddr.s_addr, bc->macaddr);
346	return q - rbp->bp_vend; /return offset /
347	}
348
349	static int dhcp_send_nack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
350	{
351	struct bootp_t *rbp;
352	uint8_t *q = NULL;
353	rbp = mtod(m, struct bootp_t *);
354
355	dhcp_create_msg(pData, bp, m, DHCPNAK);
356	return 7;
357	}
358
359	static int dhcp_send_ack(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m, int fDhcpRequest)
360	{
361	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
362
363	dhcp_create_msg(pData, bp, m, DHCPACK);
364	offReply = dhcp_do_ack_offer(pData, m, bc, fDhcpRequest);
365	return offReply;
366	}
367
368	static int dhcp_send_offer(PNATState pData, struct bootp_t bp, BOOTPClient bc, struct mbuf *m)
369	{
370	int offReply = 0; /* boot_reply will fill general options and add END before sending response */
371
372	dhcp_create_msg(pData, bp, m, DHCPOFFER);
373	offReply = dhcp_do_ack_offer(pData, m, bc, /* fDhcpRequest=*/ 0);
374	return offReply;
375	}
376
377	/**
378	* decoding client messages RFC2131 (4.3.6)
379	* ---------------------------------------------------------------------
380	* \| \|INIT-REBOOT \|SELECTING \|RENEWING \|REBINDING \|
381	* ---------------------------------------------------------------------
382	* \|broad/unicast \|broadcast \|broadcast \|unicast \|broadcast \|
383	* \|server-ip \|MUST NOT \|MUST \|MUST NOT \|MUST NOT \|
384	* \|requested-ip \|MUST \|MUST \|MUST NOT \|MUST NOT \|
385	* \|ciaddr \|zero \|zero \|IP address \|IP address\|
386	* ---------------------------------------------------------------------
387	*
388	*/
389
390	enum DHCP_REQUEST_STATES
391	{
392	INIT_REBOOT,
393	SELECTING,
394	RENEWING,
395	REBINDING,
396	NONE
397	};
398
399	static int dhcp_decode_request(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, struct mbuf *m)
400	{
401	BOOTPClient *bc = NULL;
402	struct in_addr daddr;
403	int offReply;
404	uint8_t *req_ip = NULL;
405	uint8_t *server_ip = NULL;
406	uint32_t ui32;
407	enum DHCP_REQUEST_STATES dhcp_stat = NONE;
408
409	/* need to understand which type of request we get */
410	req_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
411	server_ip = dhcp_find_option(&bp->bp_vend[0], RFC2132_SRV_ID);
412	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
413
414	if (server_ip != NULL)
415	{
416	/* selecting */
417	if (!bc)
418	{
419	LogRel(("NAT: DHCP no IP was allocated\n"));
420	return -1;
421	}
422
423	dhcp_stat = SELECTING;
424	Assert((bp->bp_ciaddr.s_addr == INADDR_ANY));
425	Assert(((uint32_t )(req_ip + 2) == bc->addr.s_addr)); /the same address as in offer/
426	#if 0
427	/* DSL xid in request differ from offer */
428	Assert((bp->bp_xid == bc->xid));
429	#endif
430	}
431	else
432	{
433	if (req_ip != NULL)
434	{
435	/* init-reboot */
436	dhcp_stat = INIT_REBOOT;
437	}
438	else
439	{
440	/* table 4 of rfc2131 */
441	if (bp->bp_flags & RT_H2N_U16_C(DHCP_FLAGS_B))
442	dhcp_stat = REBINDING;
443	else
444	dhcp_stat = RENEWING;
445	}
446	}
447
448	/?? renewing ??/
449	switch (dhcp_stat)
450	{
451	case RENEWING:
452	Assert((server_ip == NULL && req_ip == NULL && bp->bp_ciaddr.s_addr != INADDR_ANY));
453	if (bc != NULL)
454	{
455	Assert((bc->addr.s_addr == bp->bp_ciaddr.s_addr));
456	/if it already here well just do ack, we aren't aware of dhcp time expiration/
457	}
458	else
459	{
460	if ((bp->bp_ciaddr.s_addr & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
461	{
462	LogRel(("NAT: Client %R[IP4] requested IP -- sending NAK\n", &bp->bp_ciaddr));
463	offReply = dhcp_send_nack(pData, bp, bc, m);
464	return offReply;
465	}
466
467	bc = bc_alloc_client(pData);
468	if (!bc)
469	{
470	LogRel(("NAT: can't alloc address. RENEW has been silently ignored.\n"));
471	return -1;
472	}
473
474	Assert((bp->bp_hlen == ETH_ALEN));
475	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
476	bc->addr.s_addr = bp->bp_ciaddr.s_addr;
477	}
478	break;
479
480	case INIT_REBOOT:
481	Assert(server_ip == NULL);
482	Assert(req_ip != NULL);
483	ui32 = (uint32_t )(req_ip + 2);
484	if ((ui32 & RT_H2N_U32(pData->netmask)) != pData->special_addr.s_addr)
485	{
486	LogRel(("NAT: address %R[IP4] has been requested -- sending NAK\n", &ui32));
487	offReply = dhcp_send_nack(pData, bp, bc, m);
488	return offReply;
489	}
490
491	bc = bc_alloc_client(pData);
492	if (!bc)
493	{
494	LogRel(("NAT: can't alloc address. RENEW has been silently ignored\n"));
495	return -1;
496	}
497	Assert((bp->bp_hlen == ETH_ALEN));
498	memcpy(bc->macaddr, bp->bp_hwaddr, bp->bp_hlen);
499	bc->addr.s_addr = ui32;
500	break;
501
502	case NONE:
503	Assert((dhcp_stat != NONE));
504	return -1;
505
506	default:
507	break;
508	}
509
510	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
511	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 1);
512	return offReply;
513	}
514
515	static int dhcp_decode_discover(PNATState pData, struct bootp_t bp, const uint8_t buf, int size, int fDhcpDiscover, struct mbuf *m)
516	{
517	BOOTPClient *bc;
518	struct in_addr daddr;
519	int offReply;
520
521	if (fDhcpDiscover)
522	{
523	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
524	if (!bc)
525	{
526	bc = get_new_addr(pData, &daddr);
527	if (!bc)
528	{
529	LogRel(("NAT: DHCP no IP address left\n"));
530	Log(("no address left\n"));
531	return -1;
532	}
533	memcpy(bc->macaddr, bp->bp_hwaddr, 6);
534	}
535
536	bc->xid = bp->bp_xid;
537	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
538	offReply = dhcp_send_offer(pData, bp, bc, m);
539	return offReply;
540	}
541	else
542	{
543	bc = find_addr(pData, &daddr, bp->bp_hwaddr);
544	if (!bc)
545	{
546	LogRel(("NAT: DHCP Inform was ignored no boot client was found\n"));
547	return -1;
548	}
549
550	LogRel(("NAT: DHCP offered IP address %R[IP4]\n", &bc->addr));
551	offReply = dhcp_send_ack(pData, bp, bc, m, /* fDhcpRequest=*/ 0);
552	return offReply;
553	}
554
555	return -1;
556	}
557
558	static int dhcp_decode_release(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
559	{
560	int rc = release_addr(pData, &bp->bp_ciaddr);
561	LogRel(("NAT: %s %R[IP4]\n",
562	RT_SUCCESS(rc) ? "DHCP released IP address" : "Ignored DHCP release for IP address",
563	&bp->bp_ciaddr));
564	return 0;
565	}
566	/**
567	* fields for discovering t
568	* Field DHCPDISCOVER DHCPREQUEST DHCPDECLINE,
569	* DHCPINFORM DHCPRELEASE
570	* ----- ------------ ----------- -----------
571	* 'op' BOOTREQUEST BOOTREQUEST BOOTREQUEST
572	* 'htype' (From "Assigned Numbers" RFC)
573	* 'hlen' (Hardware address length in octets)
574	* 'hops' 0 0 0
575	* 'xid' selected by client 'xid' from server selected by
576	* DHCPOFFER message client
577	* 'secs' 0 or seconds since 0 or seconds since 0
578	* DHCP process started DHCP process started
579	* 'flags' Set 'BROADCAST' Set 'BROADCAST' 0
580	* flag if client flag if client
581	* requires broadcast requires broadcast
582	* reply reply
583	* 'ciaddr' 0 (DHCPDISCOVER) 0 or client's 0 (DHCPDECLINE)
584	* client's network address client's network
585	* network address (BOUND/RENEW/REBIND) address
586	* (DHCPINFORM) (DHCPRELEASE)
587	* 'yiaddr' 0 0 0
588	* 'siaddr' 0 0 0
589	* 'giaddr' 0 0 0
590	* 'chaddr' client's hardware client's hardware client's hardware
591	* address address address
592	* 'sname' options, if options, if (unused)
593	* indicated in indicated in
594	* 'sname/file' 'sname/file'
595	* option; otherwise option; otherwise
596	* unused unused
597	* 'file' options, if options, if (unused)
598	* indicated in indicated in
599	* 'sname/file' 'sname/file'
600	* option; otherwise option; otherwise
601	* unused unused
602	* 'options' options options (unused)
603	* Requested IP address MAY MUST (in MUST
604	* (DISCOVER) SELECTING or (DHCPDECLINE),
605	* MUST NOT INIT-REBOOT) MUST NOT
606	* (INFORM) MUST NOT (in (DHCPRELEASE)
607	* BOUND or
608	* RENEWING)
609	* IP address lease time MAY MAY MUST NOT
610	* (DISCOVER)
611	* MUST NOT
612	* (INFORM)
613	* Use 'file'/'sname' fields MAY MAY MAY
614	* DHCP message type DHCPDISCOVER/ DHCPREQUEST DHCPDECLINE/
615	* DHCPINFORM DHCPRELEASE
616	* Client identifier MAY MAY MAY
617	* Vendor class identifier MAY MAY MUST NOT
618	* Server identifier MUST NOT MUST (after MUST
619	* SELECTING)
620	* MUST NOT (after
621	* INIT-REBOOT,
622	* BOUND, RENEWING
623	* or REBINDING)
624	* Parameter request list MAY MAY MUST NOT
625	* Maximum message size MAY MAY MUST NOT
626	* Message SHOULD NOT SHOULD NOT SHOULD
627	* Site-specific MAY MAY MUST NOT
628	* All others MAY MAY MUST NOT
629	*
630	*/
631	static void dhcp_decode(PNATState pData, struct bootp_t bp, const uint8_t buf, int size)
632	{
633	const uint8_t p, p_end;
634	int rc;
635	int pmsg_type;
636	struct in_addr req_ip;
637	int fDhcpDiscover = 0;
638	uint8_t *parameter_list = NULL;
639	struct mbuf *m = NULL;
640
641	pmsg_type = 0;
642	p = buf;
643	p_end = buf + size;
644	if (size < 5)
645	return;
646
647	if (memcmp(p, rfc1533_cookie, 4) != 0)
648	return;
649
650	p = dhcp_find_option(bp->bp_vend, RFC2132_MSG_TYPE);
651	Assert(p);
652	if (p == NULL)
653	return;
654	/*
655	* We're going update dns list at least once per DHCP transaction (!not on every operation
656	* within transaction), assuming that transaction can't be longer than 1 min.
657	*/
658	if ( !pData->fUseHostResolver
659	&& ( pData->dnsLastUpdate == 0
660	\|\| curtime - pData->dnsLastUpdate > 60 * 1000)) /* one minute*/
661	{
662	uint8_t i = 2; /* i = 0 - tag, i == 1 - length */
663	parameter_list = dhcp_find_option(&bp->bp_vend[0], RFC2132_PARAM_LIST);
664	for (;parameter_list && i < parameter_list[1]; ++i)
665	{
666	if (parameter_list[i] == RFC1533_DNS)
667	{
668	slirp_release_dns_list(pData);
669	slirp_init_dns_list(pData);
670	pData->dnsLastUpdate = curtime;
671	break;
672	}
673	}
674	}
675
676	if ((m = m_getcl(pData, M_DONTWAIT, MT_HEADER, M_PKTHDR)) == NULL)
677	{
678	LogRel(("NAT: can't alocate memory for response!\n"));
679	return;
680	}
681
682	switch (*(p+2))
683	{
684	case DHCPDISCOVER:
685	fDhcpDiscover = 1;
686	/**/
687	case DHCPINFORM:
688	rc = dhcp_decode_discover(pData, bp, buf, size, fDhcpDiscover, m);
689	if (rc > 0)
690	goto reply;
691	break;
692
693	case DHCPREQUEST:
694	rc = dhcp_decode_request(pData, bp, buf, size, m);
695	if (rc > 0)
696	goto reply;
697	break;
698
699	case DHCPRELEASE:
700	rc = dhcp_decode_release(pData, bp, buf, size);
701	/* no reply required */
702	break;
703
704	case DHCPDECLINE:
705	p = dhcp_find_option(&bp->bp_vend[0], RFC2132_REQ_ADDR);
706	req_ip.s_addr = (uint32_t )(p + 2);
707	rc = bootp_cache_lookup_ether_by_ip(pData, req_ip.s_addr, NULL);
708	if (RT_FAILURE(rc))
709	{
710	/* Not registered */
711	BOOTPClient *bc;
712	bc = bc_alloc_client(pData);
713	Assert(bc);
714	bc->addr.s_addr = req_ip.s_addr;
715	slirp_arp_who_has(pData, bc->addr.s_addr);
716	LogRel(("NAT: %R[IP4] has been already registered\n", &req_ip));
717	}
718	/* no response required */
719	break;
720
721	default:
722	AssertMsgFailed(("unsupported DHCP message type"));
723	}
724	Assert(m);
725	/silently ignore/
726	m_freem(pData, m);
727	return;
728
729	reply:
730	bootp_reply(pData, m, rc, bp->bp_flags);
731	return;
732	}
733
734	static void bootp_reply(PNATState pData, struct mbuf *m, int offReply, uint16_t flags)
735	{
736	struct sockaddr_in saddr, daddr;
737	struct bootp_t *rbp = NULL;
738	uint8_t *q = NULL;
739	int nack;
740	rbp = mtod(m, struct bootp_t *);
741	Assert((m));
742	Assert((rbp));
743	q = rbp->bp_vend;
744	nack = (q[6] == DHCPNAK);
745	q += offReply;
746
747	#ifndef VBOX_WITH_NAT_SERVICE
748	saddr.sin_addr.s_addr = RT_H2N_U32(RT_N2H_U32(pData->special_addr.s_addr) \| CTL_ALIAS);
749	#else
750	saddr.sin_addr.s_addr = pData->special_addr.s_addr;
751	#endif
752
753	FILL_BOOTP_EXT(q, RFC2132_SRV_ID, 4, &saddr.sin_addr);
754
755	q++ = RFC1533_END; / end of message */
756
757	m->m_pkthdr.header = mtod(m, void *);
758	m->m_len = sizeof(struct bootp_t)
759	- sizeof(struct ip)
760	- sizeof(struct udphdr);
761	m->m_data += sizeof(struct udphdr)
762	+ sizeof(struct ip);
763	if ( (flags & RT_H2N_U16_C(DHCP_FLAGS_B))
764	\|\| nack != 0)
765	daddr.sin_addr.s_addr = INADDR_BROADCAST;
766	else
767	daddr.sin_addr.s_addr = rbp->bp_yiaddr.s_addr; /unicast requested by client/
768	saddr.sin_port = RT_H2N_U16_C(BOOTP_SERVER);
769	daddr.sin_port = RT_H2N_U16_C(BOOTP_CLIENT);
770	udp_output2(pData, NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
771	}
772
773	void bootp_input(PNATState pData, struct mbuf *m)
774	{
775	struct bootp_t bp = mtod(m, struct bootp_t );
776
777	if (bp->bp_op == BOOTP_REQUEST)
778	dhcp_decode(pData, bp, bp->bp_vend, DHCP_OPT_LEN);
779	}
780
781	int bootp_cache_lookup_ip_by_ether(PNATState pData,const uint8_t* ether, uint32_t *pip)
782	{
783	int i;
784
785	if (!ether \|\| !pip)
786	return VERR_INVALID_PARAMETER;
787
788	for (i = 0; i < NB_ADDR; i++)
789	{
790	if ( bootp_clients[i].allocated
791	&& memcmp(bootp_clients[i].macaddr, ether, ETH_ALEN) == 0)
792	{
793	*pip = bootp_clients[i].addr.s_addr;
794	return VINF_SUCCESS;
795	}
796	}
797
798	*pip = INADDR_ANY;
799	return VERR_NOT_FOUND;
800	}
801
802	int bootp_cache_lookup_ether_by_ip(PNATState pData, uint32_t ip, uint8_t *ether)
803	{
804	int i;
805	for (i = 0; i < NB_ADDR; i++)
806	{
807	if ( bootp_clients[i].allocated
808	&& ip == bootp_clients[i].addr.s_addr)
809	{
810	if (ether != NULL)
811	memcpy(ether, bootp_clients[i].macaddr, ETH_ALEN);
812	return VINF_SUCCESS;
813	}
814	}
815
816	return VERR_NOT_FOUND;
817	}
818
819	/*
820	* Initialize dhcp server
821	* @returns 0 - if initialization is ok, non-zero otherwise
822	*/
823	int bootp_dhcp_init(PNATState pData)
824	{
825	pData->pbootp_clients = RTMemAllocZ(sizeof(BOOTPClient) * NB_ADDR);
826	if (!pData->pbootp_clients)
827	return VERR_NO_MEMORY;
828
829	return VINF_SUCCESS;
830	}
831
832	int bootp_dhcp_fini(PNATState pData)
833	{
834	if (pData->pbootp_clients != NULL)
835	RTMemFree(pData->pbootp_clients);
836
837	return VINF_SUCCESS;
838	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/bootp.c@ 30016

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