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1.1 root 1: /*
2: * QEMU BOOTP/DHCP server
1.1.1.3 root 3: *
1.1 root 4: * Copyright (c) 2004 Fabrice Bellard
1.1.1.3 root 5: *
1.1 root 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:
1.1.1.4 ! root 39: static BOOTPClient bootp_clients[NB_ADDR];
1.1 root 40:
1.1.1.3 root 41: const char *bootp_filename;
42:
1.1 root 43: static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
44:
45: #ifdef DEBUG
46: #define dprintf(fmt, args...) \
47: if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## args); fflush(dfd); }
48: #else
49: #define dprintf(fmt, args...)
50: #endif
51:
52: static BOOTPClient *get_new_addr(struct in_addr *paddr)
53: {
54: BOOTPClient *bc;
55: int i;
56:
57: for(i = 0; i < NB_ADDR; i++) {
58: if (!bootp_clients[i].allocated)
59: goto found;
60: }
61: return NULL;
62: found:
63: bc = &bootp_clients[i];
64: bc->allocated = 1;
65: paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR));
66: return bc;
67: }
68:
69: static BOOTPClient *find_addr(struct in_addr *paddr, const uint8_t *macaddr)
70: {
71: BOOTPClient *bc;
72: int i;
73:
74: for(i = 0; i < NB_ADDR; i++) {
75: if (!memcmp(macaddr, bootp_clients[i].macaddr, 6))
76: goto found;
77: }
78: return NULL;
79: found:
80: bc = &bootp_clients[i];
81: bc->allocated = 1;
82: paddr->s_addr = htonl(ntohl(special_addr.s_addr) | (i + START_ADDR));
83: return bc;
84: }
85:
86: static void dhcp_decode(const uint8_t *buf, int size,
87: int *pmsg_type)
88: {
89: const uint8_t *p, *p_end;
90: int len, tag;
91:
1.1.1.3 root 92: *pmsg_type = 0;
1.1 root 93:
94: p = buf;
95: p_end = buf + size;
96: if (size < 5)
97: return;
98: if (memcmp(p, rfc1533_cookie, 4) != 0)
99: return;
100: p += 4;
101: while (p < p_end) {
102: tag = p[0];
103: if (tag == RFC1533_PAD) {
1.1.1.3 root 104: p++;
1.1 root 105: } else if (tag == RFC1533_END) {
106: break;
107: } else {
108: p++;
109: if (p >= p_end)
110: break;
111: len = *p++;
112: dprintf("dhcp: tag=0x%02x len=%d\n", tag, len);
113:
114: switch(tag) {
115: case RFC2132_MSG_TYPE:
116: if (len >= 1)
117: *pmsg_type = p[0];
118: break;
119: default:
120: break;
121: }
122: p += len;
123: }
124: }
125: }
126:
127: static void bootp_reply(struct bootp_t *bp)
128: {
129: BOOTPClient *bc;
130: struct mbuf *m;
131: struct bootp_t *rbp;
132: struct sockaddr_in saddr, daddr;
133: struct in_addr dns_addr;
134: int dhcp_msg_type, val;
135: uint8_t *q;
136:
137: /* extract exact DHCP msg type */
138: dhcp_decode(bp->bp_vend, DHCP_OPT_LEN, &dhcp_msg_type);
139: dprintf("bootp packet op=%d msgtype=%d\n", bp->bp_op, dhcp_msg_type);
1.1.1.3 root 140:
1.1 root 141: if (dhcp_msg_type == 0)
142: dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
1.1.1.3 root 143:
144: if (dhcp_msg_type != DHCPDISCOVER &&
1.1 root 145: dhcp_msg_type != DHCPREQUEST)
146: return;
147: /* XXX: this is a hack to get the client mac address */
148: memcpy(client_ethaddr, bp->bp_hwaddr, 6);
1.1.1.3 root 149:
1.1 root 150: if ((m = m_get()) == NULL)
151: return;
1.1.1.3 root 152: m->m_data += IF_MAXLINKHDR;
1.1 root 153: rbp = (struct bootp_t *)m->m_data;
154: m->m_data += sizeof(struct udpiphdr);
155: memset(rbp, 0, sizeof(struct bootp_t));
156:
157: if (dhcp_msg_type == DHCPDISCOVER) {
158: new_addr:
159: bc = get_new_addr(&daddr.sin_addr);
160: if (!bc) {
161: dprintf("no address left\n");
162: return;
163: }
164: memcpy(bc->macaddr, client_ethaddr, 6);
165: } else {
166: bc = find_addr(&daddr.sin_addr, bp->bp_hwaddr);
167: if (!bc) {
168: /* if never assigned, behaves as if it was already
169: assigned (windows fix because it remembers its address) */
170: goto new_addr;
171: }
172: }
1.1.1.3 root 173:
174: if (bootp_filename)
1.1.1.4 ! root 175: snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s",
! 176: bootp_filename);
1.1.1.3 root 177:
1.1 root 178: dprintf("offered addr=%08x\n", ntohl(daddr.sin_addr.s_addr));
179:
180: saddr.sin_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_ALIAS);
181: saddr.sin_port = htons(BOOTP_SERVER);
182:
183: daddr.sin_port = htons(BOOTP_CLIENT);
184:
185: rbp->bp_op = BOOTP_REPLY;
186: rbp->bp_xid = bp->bp_xid;
187: rbp->bp_htype = 1;
188: rbp->bp_hlen = 6;
189: memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6);
190:
191: rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
192: rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
193:
1.1.1.4 ! root 194: daddr.sin_addr.s_addr = 0xffffffffu;
! 195:
1.1 root 196: q = rbp->bp_vend;
197: memcpy(q, rfc1533_cookie, 4);
198: q += 4;
199:
200: if (dhcp_msg_type == DHCPDISCOVER) {
201: *q++ = RFC2132_MSG_TYPE;
202: *q++ = 1;
203: *q++ = DHCPOFFER;
204: } else if (dhcp_msg_type == DHCPREQUEST) {
205: *q++ = RFC2132_MSG_TYPE;
206: *q++ = 1;
207: *q++ = DHCPACK;
208: }
1.1.1.3 root 209:
1.1 root 210: if (dhcp_msg_type == DHCPDISCOVER ||
211: dhcp_msg_type == DHCPREQUEST) {
212: *q++ = RFC2132_SRV_ID;
213: *q++ = 4;
214: memcpy(q, &saddr.sin_addr, 4);
215: q += 4;
216:
217: *q++ = RFC1533_NETMASK;
218: *q++ = 4;
219: *q++ = 0xff;
220: *q++ = 0xff;
221: *q++ = 0xff;
222: *q++ = 0x00;
1.1.1.3 root 223:
1.1.1.4 ! root 224: if (!slirp_restrict) {
! 225: *q++ = RFC1533_GATEWAY;
! 226: *q++ = 4;
! 227: memcpy(q, &saddr.sin_addr, 4);
! 228: q += 4;
! 229:
! 230: *q++ = RFC1533_DNS;
! 231: *q++ = 4;
! 232: dns_addr.s_addr = htonl(ntohl(special_addr.s_addr) | CTL_DNS);
! 233: memcpy(q, &dns_addr, 4);
! 234: q += 4;
! 235: }
1.1 root 236:
237: *q++ = RFC2132_LEASE_TIME;
238: *q++ = 4;
239: val = htonl(LEASE_TIME);
240: memcpy(q, &val, 4);
241: q += 4;
1.1.1.2 root 242:
243: if (*slirp_hostname) {
244: val = strlen(slirp_hostname);
245: *q++ = RFC1533_HOSTNAME;
246: *q++ = val;
247: memcpy(q, slirp_hostname, val);
248: q += val;
249: }
1.1 root 250: }
251: *q++ = RFC1533_END;
1.1.1.3 root 252:
253: m->m_len = sizeof(struct bootp_t) -
1.1 root 254: sizeof(struct ip) - sizeof(struct udphdr);
255: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
256: }
257:
258: void bootp_input(struct mbuf *m)
259: {
260: struct bootp_t *bp = mtod(m, struct bootp_t *);
261:
262: if (bp->bp_op == BOOTP_REQUEST) {
263: bootp_reply(bp);
264: }
265: }
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