linux-user: stack_base is now mandatory on all targets
[qemu.git] / slirp / bootp.c
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 #define LEASE_TIME (24 * 3600)
29
30 static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
31
32 #ifdef DEBUG
33 #define DPRINTF(fmt, ...) \
34 do if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## __VA_ARGS__); fflush(dfd); } while (0)
35 #else
36 #define DPRINTF(fmt, ...) do{}while(0)
37 #endif
38
39 static BOOTPClient *get_new_addr(Slirp *slirp, struct in_addr *paddr,
40 const uint8_t *macaddr)
41 {
42 BOOTPClient *bc;
43 int i;
44
45 for(i = 0; i < NB_BOOTP_CLIENTS; i++) {
46 bc = &slirp->bootp_clients[i];
47 if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6))
48 goto found;
49 }
50 return NULL;
51 found:
52 bc = &slirp->bootp_clients[i];
53 bc->allocated = 1;
54 paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i);
55 return bc;
56 }
57
58 static BOOTPClient *request_addr(Slirp *slirp, const struct in_addr *paddr,
59 const uint8_t *macaddr)
60 {
61 uint32_t req_addr = ntohl(paddr->s_addr);
62 uint32_t dhcp_addr = ntohl(slirp->vdhcp_startaddr.s_addr);
63 BOOTPClient *bc;
64
65 if (req_addr >= dhcp_addr &&
66 req_addr < (dhcp_addr + NB_BOOTP_CLIENTS)) {
67 bc = &slirp->bootp_clients[req_addr - dhcp_addr];
68 if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6)) {
69 bc->allocated = 1;
70 return bc;
71 }
72 }
73 return NULL;
74 }
75
76 static BOOTPClient *find_addr(Slirp *slirp, struct in_addr *paddr,
77 const uint8_t *macaddr)
78 {
79 BOOTPClient *bc;
80 int i;
81
82 for(i = 0; i < NB_BOOTP_CLIENTS; i++) {
83 if (!memcmp(macaddr, slirp->bootp_clients[i].macaddr, 6))
84 goto found;
85 }
86 return NULL;
87 found:
88 bc = &slirp->bootp_clients[i];
89 bc->allocated = 1;
90 paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i);
91 return bc;
92 }
93
94 static void dhcp_decode(const struct bootp_t *bp, int *pmsg_type,
95 struct in_addr *preq_addr)
96 {
97 const uint8_t *p, *p_end;
98 int len, tag;
99
100 *pmsg_type = 0;
101 preq_addr->s_addr = htonl(0L);
102
103 p = bp->bp_vend;
104 p_end = p + DHCP_OPT_LEN;
105 if (memcmp(p, rfc1533_cookie, 4) != 0)
106 return;
107 p += 4;
108 while (p < p_end) {
109 tag = p[0];
110 if (tag == RFC1533_PAD) {
111 p++;
112 } else if (tag == RFC1533_END) {
113 break;
114 } else {
115 p++;
116 if (p >= p_end)
117 break;
118 len = *p++;
119 DPRINTF("dhcp: tag=%d len=%d\n", tag, len);
120
121 switch(tag) {
122 case RFC2132_MSG_TYPE:
123 if (len >= 1)
124 *pmsg_type = p[0];
125 break;
126 case RFC2132_REQ_ADDR:
127 if (len >= 4) {
128 memcpy(&(preq_addr->s_addr), p, 4);
129 }
130 break;
131 default:
132 break;
133 }
134 p += len;
135 }
136 }
137 if (*pmsg_type == DHCPREQUEST && preq_addr->s_addr == htonl(0L) &&
138 bp->bp_ciaddr.s_addr) {
139 memcpy(&(preq_addr->s_addr), &bp->bp_ciaddr, 4);
140 }
141 }
142
143 static void bootp_reply(Slirp *slirp, const struct bootp_t *bp)
144 {
145 BOOTPClient *bc = NULL;
146 struct mbuf *m;
147 struct bootp_t *rbp;
148 struct sockaddr_in saddr, daddr;
149 struct in_addr preq_addr;
150 int dhcp_msg_type, val;
151 uint8_t *q;
152 uint8_t client_ethaddr[ETH_ALEN];
153
154 /* extract exact DHCP msg type */
155 dhcp_decode(bp, &dhcp_msg_type, &preq_addr);
156 DPRINTF("bootp packet op=%d msgtype=%d", bp->bp_op, dhcp_msg_type);
157 if (preq_addr.s_addr != htonl(0L))
158 DPRINTF(" req_addr=%08x\n", ntohl(preq_addr.s_addr));
159 else
160 DPRINTF("\n");
161
162 if (dhcp_msg_type == 0)
163 dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
164
165 if (dhcp_msg_type != DHCPDISCOVER &&
166 dhcp_msg_type != DHCPREQUEST)
167 return;
168
169 /* Get client's hardware address from bootp request */
170 memcpy(client_ethaddr, bp->bp_hwaddr, ETH_ALEN);
171
172 m = m_get(slirp);
173 if (!m) {
174 return;
175 }
176 m->m_data += IF_MAXLINKHDR;
177 rbp = (struct bootp_t *)m->m_data;
178 m->m_data += sizeof(struct udpiphdr);
179 memset(rbp, 0, sizeof(struct bootp_t));
180
181 if (dhcp_msg_type == DHCPDISCOVER) {
182 if (preq_addr.s_addr != htonl(0L)) {
183 bc = request_addr(slirp, &preq_addr, client_ethaddr);
184 if (bc) {
185 daddr.sin_addr = preq_addr;
186 }
187 }
188 if (!bc) {
189 new_addr:
190 bc = get_new_addr(slirp, &daddr.sin_addr, client_ethaddr);
191 if (!bc) {
192 DPRINTF("no address left\n");
193 return;
194 }
195 }
196 memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
197 } else if (preq_addr.s_addr != htonl(0L)) {
198 bc = request_addr(slirp, &preq_addr, client_ethaddr);
199 if (bc) {
200 daddr.sin_addr = preq_addr;
201 memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
202 } else {
203 daddr.sin_addr.s_addr = 0;
204 }
205 } else {
206 bc = find_addr(slirp, &daddr.sin_addr, bp->bp_hwaddr);
207 if (!bc) {
208 /* if never assigned, behaves as if it was already
209 assigned (windows fix because it remembers its address) */
210 goto new_addr;
211 }
212 }
213
214 /* Update ARP table for this IP address */
215 arp_table_add(slirp, daddr.sin_addr.s_addr, client_ethaddr);
216
217 saddr.sin_addr = slirp->vhost_addr;
218 saddr.sin_port = htons(BOOTP_SERVER);
219
220 daddr.sin_port = htons(BOOTP_CLIENT);
221
222 rbp->bp_op = BOOTP_REPLY;
223 rbp->bp_xid = bp->bp_xid;
224 rbp->bp_htype = 1;
225 rbp->bp_hlen = 6;
226 memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, ETH_ALEN);
227
228 rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
229 rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
230
231 q = rbp->bp_vend;
232 memcpy(q, rfc1533_cookie, 4);
233 q += 4;
234
235 if (bc) {
236 DPRINTF("%s addr=%08x\n",
237 (dhcp_msg_type == DHCPDISCOVER) ? "offered" : "ack'ed",
238 ntohl(daddr.sin_addr.s_addr));
239
240 if (dhcp_msg_type == DHCPDISCOVER) {
241 *q++ = RFC2132_MSG_TYPE;
242 *q++ = 1;
243 *q++ = DHCPOFFER;
244 } else /* DHCPREQUEST */ {
245 *q++ = RFC2132_MSG_TYPE;
246 *q++ = 1;
247 *q++ = DHCPACK;
248 }
249
250 if (slirp->bootp_filename)
251 snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s",
252 slirp->bootp_filename);
253
254 *q++ = RFC2132_SRV_ID;
255 *q++ = 4;
256 memcpy(q, &saddr.sin_addr, 4);
257 q += 4;
258
259 *q++ = RFC1533_NETMASK;
260 *q++ = 4;
261 memcpy(q, &slirp->vnetwork_mask, 4);
262 q += 4;
263
264 if (!slirp->restricted) {
265 *q++ = RFC1533_GATEWAY;
266 *q++ = 4;
267 memcpy(q, &saddr.sin_addr, 4);
268 q += 4;
269
270 *q++ = RFC1533_DNS;
271 *q++ = 4;
272 memcpy(q, &slirp->vnameserver_addr, 4);
273 q += 4;
274 }
275
276 *q++ = RFC2132_LEASE_TIME;
277 *q++ = 4;
278 val = htonl(LEASE_TIME);
279 memcpy(q, &val, 4);
280 q += 4;
281
282 if (*slirp->client_hostname) {
283 val = strlen(slirp->client_hostname);
284 *q++ = RFC1533_HOSTNAME;
285 *q++ = val;
286 memcpy(q, slirp->client_hostname, val);
287 q += val;
288 }
289 } else {
290 static const char nak_msg[] = "requested address not available";
291
292 DPRINTF("nak'ed addr=%08x\n", ntohl(preq_addr.s_addr));
293
294 *q++ = RFC2132_MSG_TYPE;
295 *q++ = 1;
296 *q++ = DHCPNAK;
297
298 *q++ = RFC2132_MESSAGE;
299 *q++ = sizeof(nak_msg) - 1;
300 memcpy(q, nak_msg, sizeof(nak_msg) - 1);
301 q += sizeof(nak_msg) - 1;
302 }
303 *q = RFC1533_END;
304
305 daddr.sin_addr.s_addr = 0xffffffffu;
306
307 m->m_len = sizeof(struct bootp_t) -
308 sizeof(struct ip) - sizeof(struct udphdr);
309 udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
310 }
311
312 void bootp_input(struct mbuf *m)
313 {
314 struct bootp_t *bp = mtod(m, struct bootp_t *);
315
316 if (bp->bp_op == BOOTP_REQUEST) {
317 bootp_reply(m->slirp, bp);
318 }
319 }