1/* SPDX-License-Identifier: BSD-3-Clause */
2/*
3 * Copyright (c) 1982, 1986, 1988, 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * @(#)udp_usrreq.c 8.4 (Berkeley) 1/21/94
31 * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
32 */
33
34/*
35 * Changes and additions relating to SLiRP
36 * Copyright (c) 1995 Danny Gasparovski.
37 *
38 * Please read the file COPYRIGHT for the
39 * terms and conditions of the copyright.
40 */
41
42#include "slirp.h"
43#include "ip_icmp.h"
44
45static uint8_t udp_tos(struct socket *so);
46
47void udp_init(Slirp *slirp)
48{
49 slirp->udb.so_next = slirp->udb.so_prev = &slirp->udb;
50 slirp->udp_last_so = &slirp->udb;
51}
52
53void udp_cleanup(Slirp *slirp)
54{
55 while (slirp->udb.so_next != &slirp->udb) {
56 udp_detach(slirp->udb.so_next);
57 }
58}
59
60/* m->m_data points at ip packet header
61 * m->m_len length ip packet
62 * ip->ip_len length data (IPDU)
63 */
64void udp_input(register struct mbuf *m, int iphlen)
65{
66 Slirp *slirp = m->slirp;
67 register struct ip *ip;
68 register struct udphdr *uh;
69 int len;
70 struct ip save_ip;
71 struct socket *so;
72 struct sockaddr_storage lhost;
73 struct sockaddr_in *lhost4;
74
75 DEBUG_CALL("udp_input");
76 DEBUG_ARG("m = %p", m);
77 DEBUG_ARG("iphlen = %d", iphlen);
78
79 /*
80 * Strip IP options, if any; should skip this,
81 * make available to user, and use on returned packets,
82 * but we don't yet have a way to check the checksum
83 * with options still present.
84 */
85 if (iphlen > sizeof(struct ip)) {
86 ip_stripoptions(m, (struct mbuf *)0);
87 iphlen = sizeof(struct ip);
88 }
89
90 /*
91 * Get IP and UDP header together in first mbuf.
92 */
93 ip = mtod(m, struct ip *);
94 uh = (struct udphdr *)((char *)ip + iphlen);
95
96 /*
97 * Make mbuf data length reflect UDP length.
98 * If not enough data to reflect UDP length, drop.
99 */
100 len = ntohs((uint16_t)uh->uh_ulen);
101
102 if (ip->ip_len != len) {
103 if (len > ip->ip_len) {
104 goto bad;
105 }
106 m_adj(m, len - ip->ip_len);
107 ip->ip_len = len;
108 }
109
110 /*
111 * Save a copy of the IP header in case we want restore it
112 * for sending an ICMP error message in response.
113 */
114 save_ip = *ip;
115 save_ip.ip_len += iphlen; /* tcp_input subtracts this */
116
117 /*
118 * Checksum extended UDP header and data.
119 */
120 if (uh->uh_sum) {
121 memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
122 ((struct ipovly *)ip)->ih_x1 = 0;
123 ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
124 if (cksum(m, len + sizeof(struct ip))) {
125 goto bad;
126 }
127 }
128
129 lhost.ss_family = AF_INET;
130 lhost4 = (struct sockaddr_in *)&lhost;
131 lhost4->sin_addr = ip->ip_src;
132 lhost4->sin_port = uh->uh_sport;
133
134 /*
135 * handle DHCP/BOOTP
136 */
137 if (ntohs(uh->uh_dport) == BOOTP_SERVER &&
138 (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr ||
139 ip->ip_dst.s_addr == 0xffffffff)) {
140 bootp_input(m);
141 goto bad;
142 }
143
144 /*
145 * handle TFTP
146 */
147 if (ntohs(uh->uh_dport) == TFTP_SERVER &&
148 ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
149 m->m_data += iphlen;
150 m->m_len -= iphlen;
151 tftp_input(&lhost, m);
152 m->m_data -= iphlen;
153 m->m_len += iphlen;
154 goto bad;
155 }
156
157 if (slirp->restricted) {
158 goto bad;
159 }
160
161 /*
162 * Locate pcb for datagram.
163 */
164 so = solookup(&slirp->udp_last_so, &slirp->udb, &lhost, NULL);
165
166 if (so == NULL) {
167 /*
168 * If there's no socket for this packet,
169 * create one
170 */
171 so = socreate(slirp);
172 if (udp_attach(so, AF_INET) == -1) {
173 DEBUG_MISC(" udp_attach errno = %d-%s", errno, strerror(errno));
174 sofree(so);
175 goto bad;
176 }
177
178 /*
179 * Setup fields
180 */
181 so->so_lfamily = AF_INET;
182 so->so_laddr = ip->ip_src;
183 so->so_lport = uh->uh_sport;
184
185 if ((so->so_iptos = udp_tos(so)) == 0)
186 so->so_iptos = ip->ip_tos;
187
188 /*
189 * XXXXX Here, check if it's in udpexec_list,
190 * and if it is, do the fork_exec() etc.
191 */
192 }
193
194 so->so_ffamily = AF_INET;
195 so->so_faddr = ip->ip_dst; /* XXX */
196 so->so_fport = uh->uh_dport; /* XXX */
197
198 iphlen += sizeof(struct udphdr);
199 m->m_len -= iphlen;
200 m->m_data += iphlen;
201
202 /*
203 * Now we sendto() the packet.
204 */
205 if (sosendto(so, m) == -1) {
206 m->m_len += iphlen;
207 m->m_data -= iphlen;
208 *ip = save_ip;
209 DEBUG_MISC("udp tx errno = %d-%s", errno, strerror(errno));
210 icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
211 goto bad;
212 }
213
214 m_free(so->so_m); /* used for ICMP if error on sorecvfrom */
215
216 /* restore the orig mbuf packet */
217 m->m_len += iphlen;
218 m->m_data -= iphlen;
219 *ip = save_ip;
220 so->so_m = m; /* ICMP backup */
221
222 return;
223bad:
224 m_free(m);
225}
226
227int udp_output(struct socket *so, struct mbuf *m, struct sockaddr_in *saddr,
228 struct sockaddr_in *daddr, int iptos)
229{
230 register struct udpiphdr *ui;
231 int error = 0;
232
233 DEBUG_CALL("udp_output");
234 DEBUG_ARG("so = %p", so);
235 DEBUG_ARG("m = %p", m);
236 DEBUG_ARG("saddr = %s", inet_ntoa(saddr->sin_addr));
237 DEBUG_ARG("daddr = %s", inet_ntoa(daddr->sin_addr));
238
239 /*
240 * Adjust for header
241 */
242 m->m_data -= sizeof(struct udpiphdr);
243 m->m_len += sizeof(struct udpiphdr);
244
245 /*
246 * Fill in mbuf with extended UDP header
247 * and addresses and length put into network format.
248 */
249 ui = mtod(m, struct udpiphdr *);
250 memset(&ui->ui_i.ih_mbuf, 0, sizeof(struct mbuf_ptr));
251 ui->ui_x1 = 0;
252 ui->ui_pr = IPPROTO_UDP;
253 ui->ui_len = htons(m->m_len - sizeof(struct ip));
254 /* XXXXX Check for from-one-location sockets, or from-any-location sockets
255 */
256 ui->ui_src = saddr->sin_addr;
257 ui->ui_dst = daddr->sin_addr;
258 ui->ui_sport = saddr->sin_port;
259 ui->ui_dport = daddr->sin_port;
260 ui->ui_ulen = ui->ui_len;
261
262 /*
263 * Stuff checksum and output datagram.
264 */
265 ui->ui_sum = 0;
266 if ((ui->ui_sum = cksum(m, m->m_len)) == 0)
267 ui->ui_sum = 0xffff;
268 ((struct ip *)ui)->ip_len = m->m_len;
269
270 ((struct ip *)ui)->ip_ttl = IPDEFTTL;
271 ((struct ip *)ui)->ip_tos = iptos;
272
273 error = ip_output(so, m);
274
275 return (error);
276}
277
278int udp_attach(struct socket *so, unsigned short af)
279{
280 so->s = slirp_socket(af, SOCK_DGRAM, 0);
281 if (so->s != -1) {
282 so->so_expire = curtime + SO_EXPIRE;
283 insque(so, &so->slirp->udb);
284 }
285 return (so->s);
286}
287
288void udp_detach(struct socket *so)
289{
290 so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque);
291 closesocket(so->s);
292 sofree(so);
293}
294
295static const struct tos_t udptos[] = { { 0, 53, IPTOS_LOWDELAY, 0 }, /* DNS */
296 { 0, 0, 0, 0 } };
297
298static uint8_t udp_tos(struct socket *so)
299{
300 int i = 0;
301
302 while (udptos[i].tos) {
303 if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
304 (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
305 so->so_emu = udptos[i].emu;
306 return udptos[i].tos;
307 }
308 i++;
309 }
310
311 return 0;
312}
313
314struct socket *udp_listen(Slirp *slirp, uint32_t haddr, unsigned hport,
315 uint32_t laddr, unsigned lport, int flags)
316{
317 /* TODO: IPv6 */
318 struct sockaddr_in addr;
319 struct socket *so;
320 socklen_t addrlen = sizeof(struct sockaddr_in);
321
322 so = socreate(slirp);
323 so->s = slirp_socket(AF_INET, SOCK_DGRAM, 0);
324 if (so->s < 0) {
325 sofree(so);
326 return NULL;
327 }
328 so->so_expire = curtime + SO_EXPIRE;
329 insque(so, &slirp->udb);
330
331 addr.sin_family = AF_INET;
332 addr.sin_addr.s_addr = haddr;
333 addr.sin_port = hport;
334
335 if (bind(so->s, (struct sockaddr *)&addr, addrlen) < 0) {
336 udp_detach(so);
337 return NULL;
338 }
339 slirp_socket_set_fast_reuse(so->s);
340
341 getsockname(so->s, (struct sockaddr *)&addr, &addrlen);
342 so->fhost.sin = addr;
343 sotranslate_accept(so);
344 so->so_lfamily = AF_INET;
345 so->so_lport = lport;
346 so->so_laddr.s_addr = laddr;
347 if (flags != SS_FACCEPTONCE)
348 so->so_expire = 0;
349
350 so->so_state &= SS_PERSISTENT_MASK;
351 so->so_state |= SS_ISFCONNECTED | flags;
352
353 return so;
354}
355