bootp.c@ 19851

Last change on this file since 19851 was 19851, checked in by vboxsync, 16 years ago
NAT: router is invalid for direct NAT
Property svn:eol-style set to `native`
File size: 12.4 KB

Line
1	/*
2	* QEMU BOOTP/DHCP server
3	*
4	* Copyright (c) 2004 Fabrice Bellard
5	*
6	* Permission is hereby granted, free of charge, to any person obtaining a copy
7	* of this software and associated documentation files (the "Software"), to deal
8	* in the Software without restriction, including without limitation the rights
9	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10	* copies of the Software, and to permit persons to whom the Software is
11	* furnished to do so, subject to the following conditions:
12	*
13	* The above copyright notice and this permission notice shall be included in
14	* all copies or substantial portions of the Software.
15	*
16	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22	* THE SOFTWARE.
23	*/
24	#include <slirp.h>
25
26	/* XXX: only DHCP is supported */
27
28	static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
29
30	static BOOTPClient get_new_addr(PNATState pData, struct in_addr paddr)
31	{
32	int i;
33
34	for(i = 0; i < NB_ADDR; i++)
35	{
36	if (!bootp_clients[i].allocated)
37	{
38	BOOTPClient *bc;
39
40	bc = &bootp_clients[i];
41	bc->allocated = 1;
42	paddr->s_addr = htonl(ntohl(special_addr.s_addr) \| (i + START_ADDR));
43	#ifdef VBOX_WITHOUT_SLIRP_CLIENT_ETHER
44	bc->addr.s_addr = paddr->s_addr;
45	#endif
46	return bc;
47	}
48	}
49	return NULL;
50	}
51
52	static int release_addr(PNATState pData, struct in_addr *paddr)
53	{
54	unsigned i;
55
56	i = ntohl(paddr->s_addr) - START_ADDR - ntohl(special_addr.s_addr);
57	if (i >= NB_ADDR)
58	return 0;
59
60	memset(bootp_clients[i].macaddr, '\0', 6);
61	bootp_clients[i].allocated = 0;
62	return 1;
63	}
64
65	static BOOTPClient find_addr(PNATState pData, struct in_addr paddr, const uint8_t *macaddr)
66	{
67	int i;
68
69	for(i = 0; i < NB_ADDR; i++)
70	{
71	if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
72	{
73	BOOTPClient *bc;
74
75	bc = &bootp_clients[i];
76	bc->allocated = 1;
77	paddr->s_addr = htonl(ntohl(special_addr.s_addr) \| (i + START_ADDR));
78	return bc;
79	}
80	}
81	return NULL;
82	}
83
84	static void dhcp_decode(const uint8_t *buf, int size,
85	int pmsg_type, struct in_addr req_ip)
86	{
87	const uint8_t p, p_end;
88	int len, tag;
89
90	*pmsg_type = 0;
91
92	p = buf;
93	p_end = buf + size;
94	if (size < 5)
95	return;
96	if (memcmp(p, rfc1533_cookie, 4) != 0)
97	return;
98	p += 4;
99	while (p < p_end)
100	{
101	tag = p[0];
102	if (tag == RFC1533_PAD)
103	p++;
104	else if (tag == RFC1533_END)
105	break;
106	else
107	{
108	p++;
109	if (p >= p_end)
110	break;
111	len = *p++;
112	Log(("dhcp: tag=0x%02x len=%d\n", tag, len));
113
114	switch(tag)
115	{
116	case RFC2132_REQ_ADDR:
117	if (len >= 4)
118	req_ip = (struct in_addr*)p;
119	break;
120	case RFC2132_MSG_TYPE:
121	if (len >= 1)
122	*pmsg_type = p[0];
123	break;
124	default:
125	break;
126	}
127	p += len;
128	}
129	}
130	}
131
132	#ifndef VBOX_WITHOUT_SLIRP_CLIENT_ETHER
133	static void bootp_reply(PNATState pData, struct bootp_t *bp)
134	#else
135	static void bootp_reply(PNATState pData, struct mbuf *m0)
136	#endif
137	{
138	BOOTPClient *bc;
139	struct mbuf m; / XXX: @todo vasily - it'd be better to reuse this mbuf here */
140	#ifdef VBOX_WITHOUT_SLIRP_CLIENT_ETHER
141	struct bootp_t bp = mtod(m0, struct bootp_t );
142	struct ethhdr *eh;
143	#endif
144	struct bootp_t *rbp;
145	struct sockaddr_in saddr, daddr;
146	#ifndef VBOX_WITH_MULTI_DNS
147	struct in_addr dns_addr_dhcp;
148	#endif
149	int dhcp_msg_type, val;
150	uint8_t *q;
151	struct in_addr requested_ip; /* the requested IP in DHCPREQUEST */
152	int send_nak = 0;
153
154	#define FILL_BOOTP_EXT(q, tag, len, pvalue) \
155	do { \
156	struct bootp_ext be = (struct bootp_ext )(q); \
157	be->bpe_tag = (tag); \
158	be->bpe_len = (len); \
159	memcpy(&be[1], (pvalue), (len)); \
160	(q) = (uint8_t *)(&be[1]) + (len); \
161	}while(0)
162	/* appending another value to tag, calculates len of whole block*/
163	#define FILL_BOOTP_APP(head, q, tag, len, pvalue) \
164	do { \
165	struct bootp_ext be = (struct bootp_ext )(head); \
166	memcpy(q, (pvalue), (len)); \
167	(q) += (len); \
168	Assert(be->bpe_tag == (tag)); \
169	be->bpe_len += (len); \
170	}while(0)
171
172	/* extract exact DHCP msg type */
173	requested_ip.s_addr = 0xffffffff;
174	dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type, &requested_ip);
175	Log(("bootp packet op=%d msgtype=%d\n", bp->bp_op, dhcp_msg_type));
176
177	if (dhcp_msg_type == 0)
178	dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
179
180	if (dhcp_msg_type == DHCPRELEASE)
181	{
182	int rc;
183	rc = release_addr(pData, &bp->bp_ciaddr);
184	LogRel(("NAT: %s %R[IP4]\n",
185	rc ? "DHCP released IP address" : "Ignored DHCP release for IP address",
186	&bp->bp_ciaddr));
187	/* This message is not to be answered in any way. */
188	return;
189	}
190	if ( dhcp_msg_type != DHCPDISCOVER
191	&& dhcp_msg_type != DHCPREQUEST)
192	return;
193
194	#ifndef VBOX_WITHOUT_SLIRP_CLIENT_ETHER
195	/* XXX: this is a hack to get the client mac address */
196	memcpy(client_ethaddr, bp->bp_hwaddr, 6);
197	#endif
198
199	if ((m = m_get(pData)) == NULL)
200	return;
201	#ifdef VBOX_WITHOUT_SLIRP_CLIENT_ETHER
202	eh = mtod(m, struct ethhdr *);
203	memcpy(eh->h_source, bp->bp_hwaddr, ETH_ALEN); /* XXX: if_encap just swap source with dest*/
204	#endif
205	m->m_data += if_maxlinkhdr; /reserve ether header /
206	rbp = mtod(m, struct bootp_t *);
207	memset(rbp, 0, sizeof(struct bootp_t));
208
209	if (dhcp_msg_type == DHCPDISCOVER)
210	{
211	/* Do not allocate a new lease for clients that forgot that they had a lease. */
212	bc = find_addr(pData, &daddr.sin_addr, bp->bp_hwaddr);
213	if (!bc)
214	{
215	new_addr:
216	bc = get_new_addr(pData, &daddr.sin_addr);
217	if (!bc)
218	{
219	LogRel(("NAT: DHCP no IP address left\n"));
220	Log(("no address left\n"));
221	return;
222	}
223	#ifdef VBOX_WITHOUT_SLIRP_CLIENT_ETHER
224	memcpy(bc->macaddr, bp->bp_hwaddr, 6);
225	#else
226	memcpy(bc->macaddr, client_ethaddr, 6);
227	#endif
228	}
229	}
230	else
231	{
232	bc = find_addr(pData, &daddr.sin_addr, bp->bp_hwaddr);
233	if (!bc)
234	{
235	/* if never assigned, behaves as if it was already
236	assigned (windows fix because it remembers its address) */
237	goto new_addr;
238	}
239	}
240
241	if ( tftp_prefix
242	&& RTDirExists(tftp_prefix)
243	&& bootp_filename)
244	RTStrPrintf((char*)rbp->bp_file, sizeof(rbp->bp_file), "%s", bootp_filename);
245
246	/* Address/port of the DHCP server. */
247	#ifndef VBOX_WITH_NAT_SERVICE
248	saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) \| CTL_ALIAS);
249	#else
250	saddr.sin_addr.s_addr = special_addr.s_addr;
251	#endif
252
253	saddr.sin_port = htons(BOOTP_SERVER);
254
255	daddr.sin_port = htons(BOOTP_CLIENT);
256
257	rbp->bp_op = BOOTP_REPLY;
258	rbp->bp_xid = bp->bp_xid;
259	rbp->bp_htype = 1;
260	rbp->bp_hlen = 6;
261	memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
262
263	rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
264	rbp->bp_siaddr = pData->tftp_server; /* Next Server IP address, i.e. TFTP */
265
266	q = rbp->bp_vend;
267	memcpy(q, rfc1533_cookie, 4);
268	q += 4;
269
270	if (dhcp_msg_type == DHCPDISCOVER)
271	{
272	*q++ = RFC2132_MSG_TYPE;
273	*q++ = 1;
274	*q++ = DHCPOFFER;
275	}
276	else if (dhcp_msg_type == DHCPREQUEST)
277	{
278	*q++ = RFC2132_MSG_TYPE;
279	*q++ = 1;
280	if ( requested_ip.s_addr != 0xffffffff
281	&& requested_ip.s_addr != daddr.sin_addr.s_addr)
282	{
283	/* network changed */
284	*q++ = DHCPNAK;
285	send_nak = 1;
286	}
287	else
288	*q++ = DHCPACK;
289	}
290
291	if (send_nak)
292	LogRel(("NAT: Client requested IP address %R[IP4] -- sending NAK\n",
293	&requested_ip));
294	else
295	LogRel(("NAT: DHCP offered IP address %R[IP4]\n",
296	&daddr.sin_addr));
297	if ( dhcp_msg_type == DHCPDISCOVER
298	\|\| dhcp_msg_type == DHCPREQUEST)
299	{
300	FILL_BOOTP_EXT(q, RFC2132_SRV_ID, 4, &saddr.sin_addr);
301	}
302
303	if (!send_nak &&
304	( dhcp_msg_type == DHCPDISCOVER
305	\|\| dhcp_msg_type == DHCPREQUEST))
306	{
307	#ifdef VBOX_WITH_MULTI_DNS
308	struct dns_entry *de = NULL;
309	struct dns_domain_entry *dd = NULL;
310	int added = 0;
311	uint8_t *q_dns_header = NULL;
312	#endif
313	uint32_t lease_time = htonl(LEASE_TIME);
314	uint32_t netmask = htonl(pData->netmask);
315
316	FILL_BOOTP_EXT(q, RFC1533_NETMASK, 4, &netmask);
317	FILL_BOOTP_EXT(q, RFC1533_GATEWAY, 4, &saddr.sin_addr);
318
319	#ifndef VBOX_WITH_MULTI_DNS
320	dns_addr_dhcp.s_addr = htonl(ntohl(special_addr.s_addr) \| CTL_DNS);
321	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &dns_addr_dhcp.s_addr);
322	#else
323	# ifdef VBOX_WITH_SLIRP_DNS_PROXY
324	if (pData->use_dns_proxy)
325	{
326	uint32_t addr = htonl(ntohl(special_addr.s_addr) \| CTL_DNS);
327	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &addr);
328	goto skip_dns_servers;
329	}
330	# endif
331
332
333	if (!LIST_EMPTY(&pData->dns_list_head))
334	{
335	de = LIST_FIRST(&pData->dns_list_head);
336	q_dns_header = q;
337	FILL_BOOTP_EXT(q, RFC1533_DNS, 4, &de->de_addr.s_addr);
338	}
339
340	LIST_FOREACH(de, &pData->dns_list_head, de_list)
341	{
342	if (LIST_FIRST(&pData->dns_list_head) == de)
343	continue; /* first value with head we've ingected before */
344	FILL_BOOTP_APP(q_dns_header, q, RFC1533_DNS, 4, &de->de_addr.s_addr);
345	}
346
347	#ifdef VBOX_WITH_SLIRP_DNS_PROXY
348	skip_dns_servers:
349	#endif
350	if (LIST_EMPTY(&pData->dns_domain_list_head))
351	{
352	/* Microsoft dhcp client doen't like domain-less dhcp and trimmed packets*/
353	/* dhcpcd client very sad if no domain name is passed */
354	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, " ");
355	}
356	LIST_FOREACH(dd, &pData->dns_domain_list_head, dd_list)
357	{
358
359	if (dd->dd_pszDomain == NULL)
360	continue;
361	if (added != 0)
362	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, 1, ","); /* never meet valid separator here in RFC1533*/
363	else
364	added = 1;
365	val = (int)strlen(dd->dd_pszDomain);
366	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, val, dd->dd_pszDomain);
367	}
368	#endif
369
370	FILL_BOOTP_EXT(q, RFC2132_LEASE_TIME, 4, &lease_time);
371
372	if (*slirp_hostname)
373	{
374	val = (int)strlen(slirp_hostname);
375	FILL_BOOTP_EXT(q, RFC1533_HOSTNAME, val, slirp_hostname);
376	}
377
378	#ifndef VBOX_WITH_MULTI_DNS
379	if (pData->pszDomain && pData->fPassDomain)
380	{
381	val = (int)strlen(pData->pszDomain);
382	FILL_BOOTP_EXT(q, RFC1533_DOMAINNAME, val, pData->pszDomain);
383	}
384	#endif
385	}
386	*q++ = RFC1533_END;
387
388	m->m_len = sizeof(struct bootp_t)
389	- sizeof(struct ip)
390	- sizeof(struct udphdr);
391	m->m_data += sizeof(struct udphdr)
392	+ sizeof(struct ip);
393	/* Reply to the broadcast address, as some clients perform paranoid checks. */
394	daddr.sin_addr.s_addr = INADDR_BROADCAST;
395	udp_output2(pData, NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
396	}
397
398	void bootp_input(PNATState pData, struct mbuf *m)
399	{
400	struct bootp_t bp = mtod(m, struct bootp_t );
401
402	if (bp->bp_op == BOOTP_REQUEST)
403	#ifndef VBOX_WITHOUT_SLIRP_CLIENT_ETHER
404	bootp_reply(pData, bp);
405	#else
406	bootp_reply(pData, m);
407	#endif
408	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/bootp.c@ 19851

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