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1.1 root 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 NB_ADDR 16
29:
30: #define START_ADDR 15
31:
32: #define LEASE_TIME (24 * 3600)
33:
34: typedef struct {
35: uint8_t allocated;
36: uint8_t macaddr[6];
37: } BOOTPClient;
38:
39: BOOTPClient bootp_clients[NB_ADDR];
40:
41: static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
42:
43: #ifdef DEBUG
44: #define dprintf(fmt, args...) \
45: if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## args); fflush(dfd); }
46: #else
47: #define dprintf(fmt, args...)
48: #endif
49:
50: static BOOTPClient *get_new_addr(struct in_addr *paddr)
51: {
52: BOOTPClient *bc;
53: int i;
54:
55: for(i = 0; i < NB_ADDR; i++) {
56: if (!bootp_clients[i].allocated)
57: goto found;
58: }
59: return NULL;
60: found:
61: bc = &bootp_clients[i];
62: bc->allocated = 1;
63: paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR));
64: return bc;
65: }
66:
67: static BOOTPClient *find_addr(struct in_addr *paddr, const uint8_t *macaddr)
68: {
69: BOOTPClient *bc;
70: int i;
71:
72: for(i = 0; i < NB_ADDR; i++) {
73: if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
74: goto found;
75: }
76: return NULL;
77: found:
78: bc = &bootp_clients[i];
79: bc->allocated = 1;
80: paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR));
81: return bc;
82: }
83:
84: static void dhcp_decode(const uint8_t *buf, int size,
85: int *pmsg_type)
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: tag = p[0];
101: if (tag == RFC1533_PAD) {
102: p++;
103: } else if (tag == RFC1533_END) {
104: break;
105: } else {
106: p++;
107: if (p >= p_end)
108: break;
109: len = *p++;
110: dprintf("dhcp: tag=0x%02x len=%d\n", tag, len);
111:
112: switch(tag) {
113: case RFC2132_MSG_TYPE:
114: if (len >= 1)
115: *pmsg_type = p[0];
116: break;
117: default:
118: break;
119: }
120: p += len;
121: }
122: }
123: }
124:
125: static void bootp_reply(struct bootp_t *bp)
126: {
127: BOOTPClient *bc;
128: struct mbuf *m;
129: struct bootp_t *rbp;
130: struct sockaddr_in saddr, daddr;
131: struct in_addr dns_addr;
132: int dhcp_msg_type, val;
133: uint8_t *q;
134:
135: /* extract exact DHCP msg type */
136: dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type);
137: dprintf("bootp packet op=%d msgtype=%d\n", bp->bp_op, dhcp_msg_type);
138:
139: if (dhcp_msg_type == 0)
140: dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
141:
142: if (dhcp_msg_type != DHCPDISCOVER &&
143: dhcp_msg_type != DHCPREQUEST)
144: return;
145: /* XXX: this is a hack to get the client mac address */
146: memcpy(client_ethaddr, bp->bp_hwaddr, 6);
147:
148: if ((m = m_get()) == NULL)
149: return;
150: m->m_data += if_maxlinkhdr;
151: rbp = (struct bootp_t *)m->m_data;
152: m->m_data += sizeof(struct udpiphdr);
153: memset(rbp, 0, sizeof(struct bootp_t));
154:
155: if (dhcp_msg_type == DHCPDISCOVER) {
156: new_addr:
157: bc = get_new_addr(&daddr.sin_addr);
158: if (!bc) {
159: dprintf("no address left\n");
160: return;
161: }
162: memcpy(bc->macaddr, client_ethaddr, 6);
163: } else {
164: bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr);
165: if (!bc) {
166: /* if never assigned, behaves as if it was already
167: assigned (windows fix because it remembers its address) */
168: goto new_addr;
169: }
170: }
171: dprintf("offered addr=%08x\n", ntohl(daddr.sin_addr.s_addr));
172:
173: saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS);
174: saddr.sin_port = htons(BOOTP_SERVER);
175:
176: daddr.sin_port = htons(BOOTP_CLIENT);
177:
178: rbp->bp_op = BOOTP_REPLY;
179: rbp->bp_xid = bp->bp_xid;
180: rbp->bp_htype = 1;
181: rbp->bp_hlen = 6;
182: memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
183:
184: rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
185: rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
186:
187: q = rbp->bp_vend;
188: memcpy(q, rfc1533_cookie, 4);
189: q += 4;
190:
191: if (dhcp_msg_type == DHCPDISCOVER) {
192: *q++ = RFC2132_MSG_TYPE;
193: *q++ = 1;
194: *q++ = DHCPOFFER;
195: } else if (dhcp_msg_type == DHCPREQUEST) {
196: *q++ = RFC2132_MSG_TYPE;
197: *q++ = 1;
198: *q++ = DHCPACK;
199: }
200:
201: if (dhcp_msg_type == DHCPDISCOVER ||
202: dhcp_msg_type == DHCPREQUEST) {
203: *q++ = RFC2132_SRV_ID;
204: *q++ = 4;
205: memcpy(q, &saddr.sin_addr, 4);
206: q += 4;
207:
208: *q++ = RFC1533_NETMASK;
209: *q++ = 4;
210: *q++ = 0xff;
211: *q++ = 0xff;
212: *q++ = 0xff;
213: *q++ = 0x00;
214:
215: *q++ = RFC1533_GATEWAY;
216: *q++ = 4;
217: memcpy(q, &saddr.sin_addr, 4);
218: q += 4;
219:
220: *q++ = RFC1533_DNS;
221: *q++ = 4;
222: dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_DNS);
223: memcpy(q, &dns_addr, 4);
224: q += 4;
225:
226: *q++ = RFC2132_LEASE_TIME;
227: *q++ = 4;
228: val = htonl(LEASE_TIME);
229: memcpy(q, &val, 4);
230: q += 4;
1.1.1.2 ! root 231:
! 232: if (*slirp_hostname) {
! 233: val = strlen(slirp_hostname);
! 234: *q++ = RFC1533_HOSTNAME;
! 235: *q++ = val;
! 236: memcpy(q, slirp_hostname, val);
! 237: q += val;
! 238: }
1.1 root 239: }
240: *q++ = RFC1533_END;
241:
242: m->m_len = sizeof(struct bootp_t) -
243: sizeof(struct ip) - sizeof(struct udphdr);
244: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
245: }
246:
247: void bootp_input(struct mbuf *m)
248: {
249: struct bootp_t *bp = mtod(m, struct bootp_t *);
250:
251: if (bp->bp_op == BOOTP_REQUEST) {
252: bootp_reply(bp);
253: }
254: }
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