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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 LEASE_TIME (24 * 3600)
29:
30: static const uint8_t rfc1533_cookie[] = { RFC1533_COOKIE };
31:
32: #ifdef DEBUG
1.1.1.6 root 33: #define DPRINTF(fmt, ...) \
1.1.1.5 root 34: do if (slirp_debug & DBG_CALL) { fprintf(dfd, fmt, ## __VA_ARGS__); fflush(dfd); } while (0)
1.1 root 35: #else
1.1.1.7 root 36: #define DPRINTF(fmt, ...) do{}while(0)
1.1 root 37: #endif
38:
1.1.1.5 root 39: static BOOTPClient *get_new_addr(Slirp *slirp, struct in_addr *paddr,
40: const uint8_t *macaddr)
1.1 root 41: {
42: BOOTPClient *bc;
43: int i;
44:
1.1.1.5 root 45: for(i = 0; i < NB_BOOTP_CLIENTS; i++) {
46: bc = &slirp->bootp_clients[i];
47: if (!bc->allocated || !memcmp(macaddr, bc->macaddr, 6))
1.1 root 48: goto found;
49: }
50: return NULL;
51: found:
1.1.1.5 root 52: bc = &slirp->bootp_clients[i];
1.1 root 53: bc->allocated = 1;
1.1.1.5 root 54: paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i);
1.1 root 55: return bc;
56: }
57:
1.1.1.5 root 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)
1.1 root 78: {
79: BOOTPClient *bc;
80: int i;
81:
1.1.1.5 root 82: for(i = 0; i < NB_BOOTP_CLIENTS; i++) {
83: if (!memcmp(macaddr, slirp->bootp_clients[i].macaddr, 6))
1.1 root 84: goto found;
85: }
86: return NULL;
87: found:
1.1.1.5 root 88: bc = &slirp->bootp_clients[i];
1.1 root 89: bc->allocated = 1;
1.1.1.5 root 90: paddr->s_addr = slirp->vdhcp_startaddr.s_addr + htonl(i);
1.1 root 91: return bc;
92: }
93:
1.1.1.5 root 94: static void dhcp_decode(const struct bootp_t *bp, int *pmsg_type,
1.1.1.7 root 95: struct in_addr *preq_addr)
1.1 root 96: {
97: const uint8_t *p, *p_end;
98: int len, tag;
99:
1.1.1.3 root 100: *pmsg_type = 0;
1.1.1.7 root 101: preq_addr->s_addr = htonl(0L);
1.1 root 102:
1.1.1.5 root 103: p = bp->bp_vend;
104: p_end = p + DHCP_OPT_LEN;
1.1 root 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) {
1.1.1.3 root 111: p++;
1.1 root 112: } else if (tag == RFC1533_END) {
113: break;
114: } else {
115: p++;
116: if (p >= p_end)
117: break;
118: len = *p++;
1.1.1.6 root 119: DPRINTF("dhcp: tag=%d len=%d\n", tag, len);
1.1 root 120:
121: switch(tag) {
122: case RFC2132_MSG_TYPE:
123: if (len >= 1)
124: *pmsg_type = p[0];
125: break;
1.1.1.5 root 126: case RFC2132_REQ_ADDR:
1.1.1.7 root 127: if (len >= 4) {
128: memcpy(&(preq_addr->s_addr), p, 4);
129: }
1.1.1.5 root 130: break;
1.1 root 131: default:
132: break;
133: }
134: p += len;
135: }
136: }
1.1.1.7 root 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);
1.1.1.5 root 140: }
1.1 root 141: }
142:
1.1.1.5 root 143: static void bootp_reply(Slirp *slirp, const struct bootp_t *bp)
1.1 root 144: {
1.1.1.5 root 145: BOOTPClient *bc = NULL;
1.1 root 146: struct mbuf *m;
147: struct bootp_t *rbp;
148: struct sockaddr_in saddr, daddr;
1.1.1.7 root 149: struct in_addr preq_addr;
1.1 root 150: int dhcp_msg_type, val;
151: uint8_t *q;
1.1.1.9 root 152: uint8_t client_ethaddr[ETH_ALEN];
1.1 root 153:
154: /* extract exact DHCP msg type */
1.1.1.5 root 155: dhcp_decode(bp, &dhcp_msg_type, &preq_addr);
1.1.1.6 root 156: DPRINTF("bootp packet op=%d msgtype=%d", bp->bp_op, dhcp_msg_type);
1.1.1.7 root 157: if (preq_addr.s_addr != htonl(0L))
158: DPRINTF(" req_addr=%08x\n", ntohl(preq_addr.s_addr));
1.1.1.5 root 159: else
1.1.1.6 root 160: DPRINTF("\n");
1.1.1.3 root 161:
1.1 root 162: if (dhcp_msg_type == 0)
163: dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
1.1.1.3 root 164:
165: if (dhcp_msg_type != DHCPDISCOVER &&
1.1 root 166: dhcp_msg_type != DHCPREQUEST)
167: return;
1.1.1.9 root 168:
169: /* Get client's hardware address from bootp request */
170: memcpy(client_ethaddr, bp->bp_hwaddr, ETH_ALEN);
1.1.1.3 root 171:
1.1.1.5 root 172: m = m_get(slirp);
173: if (!m) {
1.1 root 174: return;
1.1.1.5 root 175: }
1.1.1.3 root 176: m->m_data += IF_MAXLINKHDR;
1.1 root 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) {
1.1.1.7 root 182: if (preq_addr.s_addr != htonl(0L)) {
1.1.1.9 root 183: bc = request_addr(slirp, &preq_addr, client_ethaddr);
1.1.1.5 root 184: if (bc) {
1.1.1.7 root 185: daddr.sin_addr = preq_addr;
1.1.1.5 root 186: }
187: }
1.1 root 188: if (!bc) {
1.1.1.5 root 189: new_addr:
1.1.1.9 root 190: bc = get_new_addr(slirp, &daddr.sin_addr, client_ethaddr);
1.1.1.5 root 191: if (!bc) {
1.1.1.6 root 192: DPRINTF("no address left\n");
1.1.1.5 root 193: return;
194: }
195: }
1.1.1.9 root 196: memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
1.1.1.7 root 197: } else if (preq_addr.s_addr != htonl(0L)) {
1.1.1.9 root 198: bc = request_addr(slirp, &preq_addr, client_ethaddr);
1.1.1.5 root 199: if (bc) {
1.1.1.7 root 200: daddr.sin_addr = preq_addr;
1.1.1.9 root 201: memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
1.1.1.5 root 202: } else {
1.1.1.10! root 203: /* DHCPNAKs should be sent to broadcast */
! 204: daddr.sin_addr.s_addr = 0xffffffff;
1.1 root 205: }
206: } else {
1.1.1.5 root 207: bc = find_addr(slirp, &daddr.sin_addr, bp->bp_hwaddr);
1.1 root 208: if (!bc) {
209: /* if never assigned, behaves as if it was already
210: assigned (windows fix because it remembers its address) */
211: goto new_addr;
212: }
213: }
1.1.1.3 root 214:
1.1.1.9 root 215: /* Update ARP table for this IP address */
216: arp_table_add(slirp, daddr.sin_addr.s_addr, client_ethaddr);
217:
1.1.1.5 root 218: saddr.sin_addr = slirp->vhost_addr;
1.1 root 219: saddr.sin_port = htons(BOOTP_SERVER);
220:
221: daddr.sin_port = htons(BOOTP_CLIENT);
222:
223: rbp->bp_op = BOOTP_REPLY;
224: rbp->bp_xid = bp->bp_xid;
225: rbp->bp_htype = 1;
226: rbp->bp_hlen = 6;
1.1.1.9 root 227: memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, ETH_ALEN);
1.1 root 228:
229: rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
230: rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
231:
232: q = rbp->bp_vend;
233: memcpy(q, rfc1533_cookie, 4);
234: q += 4;
235:
1.1.1.5 root 236: if (bc) {
1.1.1.6 root 237: DPRINTF("%s addr=%08x\n",
1.1.1.5 root 238: (dhcp_msg_type == DHCPDISCOVER) ? "offered" : "ack'ed",
239: ntohl(daddr.sin_addr.s_addr));
240:
241: if (dhcp_msg_type == DHCPDISCOVER) {
242: *q++ = RFC2132_MSG_TYPE;
243: *q++ = 1;
244: *q++ = DHCPOFFER;
245: } else /* DHCPREQUEST */ {
246: *q++ = RFC2132_MSG_TYPE;
247: *q++ = 1;
248: *q++ = DHCPACK;
249: }
250:
251: if (slirp->bootp_filename)
252: snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s",
253: slirp->bootp_filename);
1.1.1.3 root 254:
1.1 root 255: *q++ = RFC2132_SRV_ID;
256: *q++ = 4;
257: memcpy(q, &saddr.sin_addr, 4);
258: q += 4;
259:
260: *q++ = RFC1533_NETMASK;
261: *q++ = 4;
1.1.1.5 root 262: memcpy(q, &slirp->vnetwork_mask, 4);
263: q += 4;
1.1.1.3 root 264:
1.1.1.5 root 265: if (!slirp->restricted) {
1.1.1.4 root 266: *q++ = RFC1533_GATEWAY;
267: *q++ = 4;
268: memcpy(q, &saddr.sin_addr, 4);
269: q += 4;
270:
271: *q++ = RFC1533_DNS;
272: *q++ = 4;
1.1.1.5 root 273: memcpy(q, &slirp->vnameserver_addr, 4);
1.1.1.4 root 274: q += 4;
275: }
1.1 root 276:
277: *q++ = RFC2132_LEASE_TIME;
278: *q++ = 4;
279: val = htonl(LEASE_TIME);
280: memcpy(q, &val, 4);
281: q += 4;
1.1.1.2 root 282:
1.1.1.5 root 283: if (*slirp->client_hostname) {
284: val = strlen(slirp->client_hostname);
1.1.1.2 root 285: *q++ = RFC1533_HOSTNAME;
286: *q++ = val;
1.1.1.5 root 287: memcpy(q, slirp->client_hostname, val);
1.1.1.2 root 288: q += val;
289: }
1.1.1.5 root 290: } else {
291: static const char nak_msg[] = "requested address not available";
292:
1.1.1.8 root 293: DPRINTF("nak'ed addr=%08x\n", ntohl(preq_addr.s_addr));
1.1.1.5 root 294:
295: *q++ = RFC2132_MSG_TYPE;
296: *q++ = 1;
297: *q++ = DHCPNAK;
298:
299: *q++ = RFC2132_MESSAGE;
300: *q++ = sizeof(nak_msg) - 1;
301: memcpy(q, nak_msg, sizeof(nak_msg) - 1);
302: q += sizeof(nak_msg) - 1;
1.1 root 303: }
1.1.1.6 root 304: *q = RFC1533_END;
1.1.1.3 root 305:
1.1.1.5 root 306: daddr.sin_addr.s_addr = 0xffffffffu;
307:
1.1.1.3 root 308: m->m_len = sizeof(struct bootp_t) -
1.1 root 309: sizeof(struct ip) - sizeof(struct udphdr);
310: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
311: }
312:
313: void bootp_input(struct mbuf *m)
314: {
315: struct bootp_t *bp = mtod(m, struct bootp_t *);
316:
317: if (bp->bp_op == BOOTP_REQUEST) {
1.1.1.5 root 318: bootp_reply(m->slirp, bp);
1.1 root 319: }
320: }
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