xref: /dragonfly/sys/netinet/udp_usrreq.c (revision 71126e33)
1 /*
2  * Copyright (c) 2004 Jeffrey M. Hsu.  All rights reserved.
3  * Copyright (c) 2004 The DragonFly Project.  All rights reserved.
4  *
5  * This code is derived from software contributed to The DragonFly Project
6  * by Jeffrey M. Hsu.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of The DragonFly Project nor the names of its
17  *    contributors may be used to endorse or promote products derived
18  *    from this software without specific, prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
24  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 /*
35  * Copyright (c) 2004 Jeffrey M. Hsu.  All rights reserved.
36  *
37  * License terms: all terms for the DragonFly license above plus the following:
38  *
39  * 4. All advertising materials mentioning features or use of this software
40  *    must display the following acknowledgement:
41  *
42  *	This product includes software developed by Jeffrey M. Hsu
43  *	for the DragonFly Project.
44  *
45  *    This requirement may be waived with permission from Jeffrey Hsu.
46  *    This requirement will sunset and may be removed on July 8 2005,
47  *    after which the standard DragonFly license (as shown above) will
48  *    apply.
49  */
50 
51 /*
52  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
53  *	The Regents of the University of California.  All rights reserved.
54  *
55  * Redistribution and use in source and binary forms, with or without
56  * modification, are permitted provided that the following conditions
57  * are met:
58  * 1. Redistributions of source code must retain the above copyright
59  *    notice, this list of conditions and the following disclaimer.
60  * 2. Redistributions in binary form must reproduce the above copyright
61  *    notice, this list of conditions and the following disclaimer in the
62  *    documentation and/or other materials provided with the distribution.
63  * 3. All advertising materials mentioning features or use of this software
64  *    must display the following acknowledgement:
65  *	This product includes software developed by the University of
66  *	California, Berkeley and its contributors.
67  * 4. Neither the name of the University nor the names of its contributors
68  *    may be used to endorse or promote products derived from this software
69  *    without specific prior written permission.
70  *
71  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
72  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
73  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
74  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
75  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
76  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
77  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
78  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
79  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
80  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
81  * SUCH DAMAGE.
82  *
83  *	@(#)udp_usrreq.c	8.6 (Berkeley) 5/23/95
84  * $FreeBSD: src/sys/netinet/udp_usrreq.c,v 1.64.2.18 2003/01/24 05:11:34 sam Exp $
85  * $DragonFly: src/sys/netinet/udp_usrreq.c,v 1.28 2004/12/03 20:29:53 joerg Exp $
86  */
87 
88 #include "opt_ipsec.h"
89 #include "opt_inet6.h"
90 
91 #include <sys/param.h>
92 #include <sys/systm.h>
93 #include <sys/kernel.h>
94 #include <sys/malloc.h>
95 #include <sys/mbuf.h>
96 #include <sys/domain.h>
97 #include <sys/proc.h>
98 #include <sys/protosw.h>
99 #include <sys/socket.h>
100 #include <sys/socketvar.h>
101 #include <sys/sysctl.h>
102 #include <sys/syslog.h>
103 #include <sys/in_cksum.h>
104 
105 #include <machine/stdarg.h>
106 
107 #include <vm/vm_zone.h>
108 
109 #include <net/if.h>
110 #include <net/route.h>
111 
112 #include <netinet/in.h>
113 #include <netinet/in_systm.h>
114 #include <netinet/ip.h>
115 #ifdef INET6
116 #include <netinet/ip6.h>
117 #endif
118 #include <netinet/in_pcb.h>
119 #include <netinet/in_var.h>
120 #include <netinet/ip_var.h>
121 #ifdef INET6
122 #include <netinet6/ip6_var.h>
123 #endif
124 #include <netinet/ip_icmp.h>
125 #include <netinet/icmp_var.h>
126 #include <netinet/udp.h>
127 #include <netinet/udp_var.h>
128 
129 #ifdef FAST_IPSEC
130 #include <netproto/ipsec/ipsec.h>
131 #endif /*FAST_IPSEC*/
132 
133 #ifdef IPSEC
134 #include <netinet6/ipsec.h>
135 #endif /*IPSEC*/
136 
137 /*
138  * UDP protocol implementation.
139  * Per RFC 768, August, 1980.
140  */
141 #ifndef	COMPAT_42
142 static int	udpcksum = 1;
143 #else
144 static int	udpcksum = 0;		/* XXX */
145 #endif
146 SYSCTL_INT(_net_inet_udp, UDPCTL_CHECKSUM, checksum, CTLFLAG_RW,
147 		&udpcksum, 0, "");
148 
149 int	log_in_vain = 0;
150 SYSCTL_INT(_net_inet_udp, OID_AUTO, log_in_vain, CTLFLAG_RW,
151     &log_in_vain, 0, "Log all incoming UDP packets");
152 
153 static int	blackhole = 0;
154 SYSCTL_INT(_net_inet_udp, OID_AUTO, blackhole, CTLFLAG_RW,
155 	&blackhole, 0, "Do not send port unreachables for refused connects");
156 
157 static int	strict_mcast_mship = 1;
158 SYSCTL_INT(_net_inet_udp, OID_AUTO, strict_mcast_mship, CTLFLAG_RW,
159 	&strict_mcast_mship, 0, "Only send multicast to member sockets");
160 
161 struct	inpcbinfo udbinfo;
162 
163 #ifndef UDBHASHSIZE
164 #define UDBHASHSIZE 16
165 #endif
166 
167 struct	udpstat udpstat;	/* from udp_var.h */
168 SYSCTL_STRUCT(_net_inet_udp, UDPCTL_STATS, stats, CTLFLAG_RW,
169     &udpstat, udpstat, "UDP statistics (struct udpstat, netinet/udp_var.h)");
170 
171 static struct	sockaddr_in udp_in = { sizeof(udp_in), AF_INET };
172 #ifdef INET6
173 struct udp_in6 {
174 	struct sockaddr_in6	uin6_sin;
175 	u_char			uin6_init_done : 1;
176 } udp_in6 = {
177 	{ sizeof(udp_in6.uin6_sin), AF_INET6 },
178 	0
179 };
180 struct udp_ip6 {
181 	struct ip6_hdr		uip6_ip6;
182 	u_char			uip6_init_done : 1;
183 } udp_ip6;
184 #endif /* INET6 */
185 
186 static void udp_append (struct inpcb *last, struct ip *ip,
187 			    struct mbuf *n, int off);
188 #ifdef INET6
189 static void ip_2_ip6_hdr (struct ip6_hdr *ip6, struct ip *ip);
190 #endif
191 
192 static int udp_detach (struct socket *so);
193 static	int udp_output (struct inpcb *, struct mbuf *, struct sockaddr *,
194 			    struct mbuf *, struct thread *);
195 
196 void
197 udp_init()
198 {
199 	in_pcbinfo_init(&udbinfo);
200 	udbinfo.hashbase = hashinit(UDBHASHSIZE, M_PCB, &udbinfo.hashmask);
201 	udbinfo.porthashbase = hashinit(UDBHASHSIZE, M_PCB,
202 					&udbinfo.porthashmask);
203 	udbinfo.wildcardhashbase = hashinit(UDBHASHSIZE, M_PCB,
204 					    &udbinfo.wildcardhashmask);
205 	udbinfo.ipi_zone = zinit("udpcb", sizeof(struct inpcb), maxsockets,
206 				 ZONE_INTERRUPT, 0);
207 	udp_thread_init();
208 }
209 
210 /*
211  * Check multicast packets to make sure they are only sent to sockets with
212  * multicast memberships for the packet's destination address and arrival
213  * interface.  Multicast packets to multicast-unaware sockets are also
214  * disallowed.
215  *
216  * Returns 0 if the packet is acceptable, -1 if it is not.
217  */
218 static __inline
219 int
220 check_multicast_membership(struct ip *ip, struct inpcb *inp, struct mbuf *m)
221 {
222 	int mshipno;
223 	struct ip_moptions *mopt;
224 
225 	if (strict_mcast_mship == 0 ||
226 	    !IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
227 		return(0);
228 	}
229 	mopt = inp->inp_moptions;
230 	if (mopt == NULL)
231 		return(-1);
232 	for (mshipno = 0; mshipno <= mopt->imo_num_memberships; ++mshipno) {
233 		if (ip->ip_dst.s_addr == mopt->imo_membership[mshipno]->inm_addr.s_addr &&
234 		    m->m_pkthdr.rcvif == mopt->imo_membership[mshipno]->inm_ifp) {
235 			return(0);
236 		}
237 	}
238 	return(-1);
239 }
240 
241 void
242 udp_input(struct mbuf *m, ...)
243 {
244 	int iphlen;
245 	struct ip *ip;
246 	struct udphdr *uh;
247 	struct inpcb *inp;
248 	struct mbuf *opts = 0;
249 	int len, off, proto;
250 	struct ip save_ip;
251 	struct sockaddr *append_sa;
252 	__va_list ap;
253 
254 	__va_start(ap, m);
255 	off = __va_arg(ap, int);
256 	proto = __va_arg(ap, int);
257 	__va_end(ap);
258 
259 	iphlen = off;
260 	udpstat.udps_ipackets++;
261 
262 	/*
263 	 * Strip IP options, if any; should skip this,
264 	 * make available to user, and use on returned packets,
265 	 * but we don't yet have a way to check the checksum
266 	 * with options still present.
267 	 */
268 	if (iphlen > sizeof (struct ip)) {
269 		ip_stripoptions(m);
270 		iphlen = sizeof(struct ip);
271 	}
272 
273 	/*
274 	 * IP and UDP headers are together in first mbuf.
275 	 * Already checked and pulled up in ip_demux().
276 	 */
277 	KASSERT(m->m_len >= iphlen + sizeof(struct udphdr),
278 	    ("UDP header not in one mbuf"));
279 
280 	ip = mtod(m, struct ip *);
281 	uh = (struct udphdr *)((caddr_t)ip + iphlen);
282 
283 	/* destination port of 0 is illegal, based on RFC768. */
284 	if (uh->uh_dport == 0)
285 		goto bad;
286 
287 	/*
288 	 * Make mbuf data length reflect UDP length.
289 	 * If not enough data to reflect UDP length, drop.
290 	 */
291 	len = ntohs((u_short)uh->uh_ulen);
292 	if (ip->ip_len != len) {
293 		if (len > ip->ip_len || len < sizeof(struct udphdr)) {
294 			udpstat.udps_badlen++;
295 			goto bad;
296 		}
297 		m_adj(m, len - ip->ip_len);
298 		/* ip->ip_len = len; */
299 	}
300 	/*
301 	 * Save a copy of the IP header in case we want restore it
302 	 * for sending an ICMP error message in response.
303 	 */
304 	save_ip = *ip;
305 
306 	/*
307 	 * Checksum extended UDP header and data.
308 	 */
309 	if (uh->uh_sum) {
310 		if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
311 			if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
312 				uh->uh_sum = m->m_pkthdr.csum_data;
313 			else
314 	                	uh->uh_sum = in_pseudo(ip->ip_src.s_addr,
315 				    ip->ip_dst.s_addr, htonl((u_short)len +
316 				    m->m_pkthdr.csum_data + IPPROTO_UDP));
317 			uh->uh_sum ^= 0xffff;
318 		} else {
319 			char b[9];
320 			bcopy(((struct ipovly *)ip)->ih_x1, b, 9);
321 			bzero(((struct ipovly *)ip)->ih_x1, 9);
322 			((struct ipovly *)ip)->ih_len = uh->uh_ulen;
323 			uh->uh_sum = in_cksum(m, len + sizeof (struct ip));
324 			bcopy(b, ((struct ipovly *)ip)->ih_x1, 9);
325 		}
326 		if (uh->uh_sum) {
327 			udpstat.udps_badsum++;
328 			m_freem(m);
329 			return;
330 		}
331 	} else
332 		udpstat.udps_nosum++;
333 
334 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
335 	    in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) {
336 		struct inpcb *last;
337 		/*
338 		 * Deliver a multicast or broadcast datagram to *all* sockets
339 		 * for which the local and remote addresses and ports match
340 		 * those of the incoming datagram.  This allows more than
341 		 * one process to receive multi/broadcasts on the same port.
342 		 * (This really ought to be done for unicast datagrams as
343 		 * well, but that would cause problems with existing
344 		 * applications that open both address-specific sockets and
345 		 * a wildcard socket listening to the same port -- they would
346 		 * end up receiving duplicates of every unicast datagram.
347 		 * Those applications open the multiple sockets to overcome an
348 		 * inadequacy of the UDP socket interface, but for backwards
349 		 * compatibility we avoid the problem here rather than
350 		 * fixing the interface.  Maybe 4.5BSD will remedy this?)
351 		 */
352 
353 		/*
354 		 * Construct sockaddr format source address.
355 		 */
356 		udp_in.sin_port = uh->uh_sport;
357 		udp_in.sin_addr = ip->ip_src;
358 		/*
359 		 * Locate pcb(s) for datagram.
360 		 * (Algorithm copied from raw_intr().)
361 		 */
362 		last = NULL;
363 #ifdef INET6
364 		udp_in6.uin6_init_done = udp_ip6.uip6_init_done = 0;
365 #endif
366 		LIST_FOREACH(inp, &udbinfo.pcblisthead, inp_list) {
367 			if (inp->inp_flags & INP_PLACEMARKER)
368 				continue;
369 #ifdef INET6
370 			if ((inp->inp_vflag & INP_IPV4) == 0)
371 				continue;
372 #endif
373 			if (inp->inp_lport != uh->uh_dport)
374 				continue;
375 			if (inp->inp_laddr.s_addr != INADDR_ANY) {
376 				if (inp->inp_laddr.s_addr !=
377 				    ip->ip_dst.s_addr)
378 					continue;
379 			}
380 			if (inp->inp_faddr.s_addr != INADDR_ANY) {
381 				if (inp->inp_faddr.s_addr !=
382 				    ip->ip_src.s_addr ||
383 				    inp->inp_fport != uh->uh_sport)
384 					continue;
385 			}
386 
387 			if (check_multicast_membership(ip, inp, m) < 0)
388 				continue;
389 
390 			if (last != NULL) {
391 				struct mbuf *n;
392 
393 #ifdef IPSEC
394 				/* check AH/ESP integrity. */
395 				if (ipsec4_in_reject_so(m, last->inp_socket))
396 					ipsecstat.in_polvio++;
397 					/* do not inject data to pcb */
398 				else
399 #endif /*IPSEC*/
400 #ifdef FAST_IPSEC
401 				/* check AH/ESP integrity. */
402 				if (ipsec4_in_reject(m, last))
403 					;
404 				else
405 #endif /*FAST_IPSEC*/
406 				if ((n = m_copy(m, 0, M_COPYALL)) != NULL)
407 					udp_append(last, ip, n,
408 						   iphlen +
409 						   sizeof(struct udphdr));
410 			}
411 			last = inp;
412 			/*
413 			 * Don't look for additional matches if this one does
414 			 * not have either the SO_REUSEPORT or SO_REUSEADDR
415 			 * socket options set.  This heuristic avoids searching
416 			 * through all pcbs in the common case of a non-shared
417 			 * port.  It * assumes that an application will never
418 			 * clear these options after setting them.
419 			 */
420 			if ((last->inp_socket->so_options&(SO_REUSEPORT|SO_REUSEADDR)) == 0)
421 				break;
422 		}
423 
424 		if (last == NULL) {
425 			/*
426 			 * No matching pcb found; discard datagram.
427 			 * (No need to send an ICMP Port Unreachable
428 			 * for a broadcast or multicast datgram.)
429 			 */
430 			udpstat.udps_noportbcast++;
431 			goto bad;
432 		}
433 #ifdef IPSEC
434 		/* check AH/ESP integrity. */
435 		if (ipsec4_in_reject_so(m, last->inp_socket)) {
436 			ipsecstat.in_polvio++;
437 			goto bad;
438 		}
439 #endif /*IPSEC*/
440 #ifdef FAST_IPSEC
441 		/* check AH/ESP integrity. */
442 		if (ipsec4_in_reject(m, last))
443 			goto bad;
444 #endif /*FAST_IPSEC*/
445 		udp_append(last, ip, m, iphlen + sizeof(struct udphdr));
446 		return;
447 	}
448 	/*
449 	 * Locate pcb for datagram.
450 	 */
451 	inp = in_pcblookup_hash(&udbinfo, ip->ip_src, uh->uh_sport,
452 	    ip->ip_dst, uh->uh_dport, 1, m->m_pkthdr.rcvif);
453 	if (inp == NULL) {
454 		if (log_in_vain) {
455 			char buf[4*sizeof "123"];
456 
457 			strcpy(buf, inet_ntoa(ip->ip_dst));
458 			log(LOG_INFO,
459 			    "Connection attempt to UDP %s:%d from %s:%d\n",
460 			    buf, ntohs(uh->uh_dport), inet_ntoa(ip->ip_src),
461 			    ntohs(uh->uh_sport));
462 		}
463 		udpstat.udps_noport++;
464 		if (m->m_flags & (M_BCAST | M_MCAST)) {
465 			udpstat.udps_noportbcast++;
466 			goto bad;
467 		}
468 		if (blackhole)
469 			goto bad;
470 #ifdef ICMP_BANDLIM
471 		if (badport_bandlim(BANDLIM_ICMP_UNREACH) < 0)
472 			goto bad;
473 #endif
474 		*ip = save_ip;
475 		ip->ip_len += iphlen;
476 		icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0);
477 		return;
478 	}
479 #ifdef IPSEC
480 	if (ipsec4_in_reject_so(m, inp->inp_socket)) {
481 		ipsecstat.in_polvio++;
482 		goto bad;
483 	}
484 #endif /*IPSEC*/
485 #ifdef FAST_IPSEC
486 	if (ipsec4_in_reject(m, inp))
487 		goto bad;
488 #endif /*FAST_IPSEC*/
489 
490 	/*
491 	 * Construct sockaddr format source address.
492 	 * Stuff source address and datagram in user buffer.
493 	 */
494 	udp_in.sin_port = uh->uh_sport;
495 	udp_in.sin_addr = ip->ip_src;
496 	if (inp->inp_flags & INP_CONTROLOPTS
497 	    || inp->inp_socket->so_options & SO_TIMESTAMP) {
498 #ifdef INET6
499 		if (inp->inp_vflag & INP_IPV6) {
500 			int savedflags;
501 
502 			ip_2_ip6_hdr(&udp_ip6.uip6_ip6, ip);
503 			savedflags = inp->inp_flags;
504 			inp->inp_flags &= ~INP_UNMAPPABLEOPTS;
505 			ip6_savecontrol(inp, &opts, &udp_ip6.uip6_ip6, m);
506 			inp->inp_flags = savedflags;
507 		} else
508 #endif
509 		ip_savecontrol(inp, &opts, ip, m);
510 	}
511  	m_adj(m, iphlen + sizeof(struct udphdr));
512 #ifdef INET6
513 	if (inp->inp_vflag & INP_IPV6) {
514 		in6_sin_2_v4mapsin6(&udp_in, &udp_in6.uin6_sin);
515 		append_sa = (struct sockaddr *)&udp_in6;
516 	} else
517 #endif
518 	append_sa = (struct sockaddr *)&udp_in;
519 	if (sbappendaddr(&inp->inp_socket->so_rcv, append_sa, m, opts) == 0) {
520 		udpstat.udps_fullsock++;
521 		goto bad;
522 	}
523 	sorwakeup(inp->inp_socket);
524 	return;
525 bad:
526 	m_freem(m);
527 	if (opts)
528 		m_freem(opts);
529 	return;
530 }
531 
532 #ifdef INET6
533 static void
534 ip_2_ip6_hdr(ip6, ip)
535 	struct ip6_hdr *ip6;
536 	struct ip *ip;
537 {
538 	bzero(ip6, sizeof(*ip6));
539 
540 	ip6->ip6_vfc = IPV6_VERSION;
541 	ip6->ip6_plen = ip->ip_len;
542 	ip6->ip6_nxt = ip->ip_p;
543 	ip6->ip6_hlim = ip->ip_ttl;
544 	ip6->ip6_src.s6_addr32[2] = ip6->ip6_dst.s6_addr32[2] =
545 		IPV6_ADDR_INT32_SMP;
546 	ip6->ip6_src.s6_addr32[3] = ip->ip_src.s_addr;
547 	ip6->ip6_dst.s6_addr32[3] = ip->ip_dst.s_addr;
548 }
549 #endif
550 
551 /*
552  * subroutine of udp_input(), mainly for source code readability.
553  * caller must properly init udp_ip6 and udp_in6 beforehand.
554  */
555 static void
556 udp_append(last, ip, n, off)
557 	struct inpcb *last;
558 	struct ip *ip;
559 	struct mbuf *n;
560 	int off;
561 {
562 	struct sockaddr *append_sa;
563 	struct mbuf *opts = 0;
564 
565 	if (last->inp_flags & INP_CONTROLOPTS ||
566 	    last->inp_socket->so_options & SO_TIMESTAMP) {
567 #ifdef INET6
568 		if (last->inp_vflag & INP_IPV6) {
569 			int savedflags;
570 
571 			if (udp_ip6.uip6_init_done == 0) {
572 				ip_2_ip6_hdr(&udp_ip6.uip6_ip6, ip);
573 				udp_ip6.uip6_init_done = 1;
574 			}
575 			savedflags = last->inp_flags;
576 			last->inp_flags &= ~INP_UNMAPPABLEOPTS;
577 			ip6_savecontrol(last, &opts, &udp_ip6.uip6_ip6, n);
578 			last->inp_flags = savedflags;
579 		} else
580 #endif
581 		ip_savecontrol(last, &opts, ip, n);
582 	}
583 #ifdef INET6
584 	if (last->inp_vflag & INP_IPV6) {
585 		if (udp_in6.uin6_init_done == 0) {
586 			in6_sin_2_v4mapsin6(&udp_in, &udp_in6.uin6_sin);
587 			udp_in6.uin6_init_done = 1;
588 		}
589 		append_sa = (struct sockaddr *)&udp_in6.uin6_sin;
590 	} else
591 #endif
592 	append_sa = (struct sockaddr *)&udp_in;
593 	m_adj(n, off);
594 	if (sbappendaddr(&last->inp_socket->so_rcv, append_sa, n, opts) == 0) {
595 		m_freem(n);
596 		if (opts)
597 			m_freem(opts);
598 		udpstat.udps_fullsock++;
599 	} else
600 		sorwakeup(last->inp_socket);
601 }
602 
603 /*
604  * Notify a udp user of an asynchronous error;
605  * just wake up so that he can collect error status.
606  */
607 void
608 udp_notify(inp, errno)
609 	struct inpcb *inp;
610 	int errno;
611 {
612 	inp->inp_socket->so_error = errno;
613 	sorwakeup(inp->inp_socket);
614 	sowwakeup(inp->inp_socket);
615 }
616 
617 void
618 udp_ctlinput(cmd, sa, vip)
619 	int cmd;
620 	struct sockaddr *sa;
621 	void *vip;
622 {
623 	struct ip *ip = vip;
624 	struct udphdr *uh;
625 	void (*notify) (struct inpcb *, int) = udp_notify;
626         struct in_addr faddr;
627 	struct inpcb *inp;
628 	int s;
629 
630 	faddr = ((struct sockaddr_in *)sa)->sin_addr;
631 	if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
632         	return;
633 
634 	if (PRC_IS_REDIRECT(cmd)) {
635 		ip = 0;
636 		notify = in_rtchange;
637 	} else if (cmd == PRC_HOSTDEAD)
638 		ip = 0;
639 	else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
640 		return;
641 	if (ip) {
642 		s = splnet();
643 		uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2));
644 		inp = in_pcblookup_hash(&udbinfo, faddr, uh->uh_dport,
645                     ip->ip_src, uh->uh_sport, 0, NULL);
646 		if (inp != NULL && inp->inp_socket != NULL)
647 			(*notify)(inp, inetctlerrmap[cmd]);
648 		splx(s);
649 	} else
650 		in_pcbnotifyall(&udbinfo.pcblisthead, faddr, inetctlerrmap[cmd],
651 		    notify);
652 }
653 
654 SYSCTL_PROC(_net_inet_udp, UDPCTL_PCBLIST, pcblist, CTLFLAG_RD, &udbinfo, 0,
655 	    in_pcblist_global, "S,xinpcb", "List of active UDP sockets");
656 
657 static int
658 udp_getcred(SYSCTL_HANDLER_ARGS)
659 {
660 	struct sockaddr_in addrs[2];
661 	struct inpcb *inp;
662 	int error, s;
663 
664 	error = suser(req->td);
665 	if (error)
666 		return (error);
667 	error = SYSCTL_IN(req, addrs, sizeof(addrs));
668 	if (error)
669 		return (error);
670 	s = splnet();
671 	inp = in_pcblookup_hash(&udbinfo, addrs[1].sin_addr, addrs[1].sin_port,
672 				addrs[0].sin_addr, addrs[0].sin_port, 1, NULL);
673 	if (inp == NULL || inp->inp_socket == NULL) {
674 		error = ENOENT;
675 		goto out;
676 	}
677 	error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
678 out:
679 	splx(s);
680 	return (error);
681 }
682 
683 SYSCTL_PROC(_net_inet_udp, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW,
684     0, 0, udp_getcred, "S,ucred", "Get the ucred of a UDP connection");
685 
686 static int
687 udp_output(inp, m, dstaddr, control, td)
688 	struct inpcb *inp;
689 	struct mbuf *m;
690 	struct sockaddr *dstaddr;
691 	struct mbuf *control;
692 	struct thread *td;
693 {
694 	struct udpiphdr *ui;
695 	int len = m->m_pkthdr.len;
696 	struct sockaddr_in *sin;	/* really is initialized before use */
697 	int error = 0;
698 
699 	if (len + sizeof(struct udpiphdr) > IP_MAXPACKET) {
700 		error = EMSGSIZE;
701 		goto release;
702 	}
703 
704 	if (inp->inp_lport == 0) {	/* unbound socket */
705 		error = in_pcbbind(inp, (struct sockaddr *)NULL, td);
706 		if (error)
707 			goto release;
708 		in_pcbinswildcardhash(inp);
709 	}
710 
711 	if (dstaddr != NULL) {		/* destination address specified */
712 		if (inp->inp_faddr.s_addr != INADDR_ANY) {
713 			/* already connected */
714 			error = EISCONN;
715 			goto release;
716 		}
717 		sin = (struct sockaddr_in *)dstaddr;
718 		prison_remote_ip(td, 0, &sin->sin_addr.s_addr);
719 	} else {
720 		if (inp->inp_faddr.s_addr == INADDR_ANY) {
721 			/* no destination specified and not already connected */
722 			error = ENOTCONN;
723 			goto release;
724 		}
725 		sin = NULL;
726 	}
727 
728 	/*
729 	 * Calculate data length and get a mbuf
730 	 * for UDP and IP headers.
731 	 */
732 	M_PREPEND(m, sizeof(struct udpiphdr), MB_DONTWAIT);
733 	if (m == 0) {
734 		error = ENOBUFS;
735 		goto release;
736 	}
737 
738 	/*
739 	 * Fill in mbuf with extended UDP header
740 	 * and addresses and length put into network format.
741 	 */
742 	ui = mtod(m, struct udpiphdr *);
743 	bzero(ui->ui_x1, sizeof(ui->ui_x1));	/* XXX still needed? */
744 	ui->ui_pr = IPPROTO_UDP;
745 
746 	/*
747 	 * Set destination address.
748 	 */
749 	if (dstaddr != NULL) {			/* use specified destination */
750 		ui->ui_dst = sin->sin_addr;
751 		ui->ui_dport = sin->sin_port;
752 	} else {				/* use connected destination */
753 		ui->ui_dst = inp->inp_faddr;
754 		ui->ui_dport = inp->inp_fport;
755 	}
756 
757 	/*
758 	 * Set source address.
759 	 */
760 	if (inp->inp_laddr.s_addr == INADDR_ANY) {
761 		struct sockaddr_in *if_sin;
762 
763 		KASSERT(dstaddr != NULL,
764 		    ("connected UDP socket without local addr: "
765 		     "lport %d, faddr %x, fport %d",
766 		     inp->inp_lport, inp->inp_faddr.s_addr, inp->inp_fport));
767 
768 		/* Look up outgoing interface. */
769 		if ((error = in_pcbladdr(inp, dstaddr, &if_sin)))
770 			goto release;
771 		ui->ui_src = if_sin->sin_addr;	/* use address of interface */
772 	} else {
773 		ui->ui_src = inp->inp_laddr;	/* use non-null bound address */
774 	}
775 	ui->ui_sport = inp->inp_lport;
776 	KASSERT(inp->inp_lport != 0, ("inp lport should have been bound"));
777 
778 	ui->ui_ulen = htons((u_short)len + sizeof(struct udphdr));
779 
780 	/*
781 	 * Set up checksum and output datagram.
782 	 */
783 	if (udpcksum) {
784         	ui->ui_sum = in_pseudo(ui->ui_src.s_addr, ui->ui_dst.s_addr,
785 		    htons((u_short)len + sizeof(struct udphdr) + IPPROTO_UDP));
786 		m->m_pkthdr.csum_flags = CSUM_UDP;
787 		m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
788 	} else {
789 		ui->ui_sum = 0;
790 	}
791 	((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len;
792 	((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl;	/* XXX */
793 	((struct ip *)ui)->ip_tos = inp->inp_ip_tos;	/* XXX */
794 	udpstat.udps_opackets++;
795 
796 	error = ip_output(m, inp->inp_options, &inp->inp_route,
797 	    (inp->inp_socket->so_options & (SO_DONTROUTE | SO_BROADCAST)),
798 	    inp->inp_moptions, inp);
799 
800 	return (error);
801 
802 release:
803 	m_freem(m);
804 	return (error);
805 }
806 
807 u_long	udp_sendspace = 9216;		/* really max datagram size */
808 					/* 40 1K datagrams */
809 SYSCTL_INT(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW,
810     &udp_sendspace, 0, "Maximum outgoing UDP datagram size");
811 
812 u_long	udp_recvspace = 40 * (1024 +
813 #ifdef INET6
814 				      sizeof(struct sockaddr_in6)
815 #else
816 				      sizeof(struct sockaddr_in)
817 #endif
818 				      );
819 SYSCTL_INT(_net_inet_udp, UDPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
820     &udp_recvspace, 0, "Maximum incoming UDP datagram size");
821 
822 static int
823 udp_abort(struct socket *so)
824 {
825 	struct inpcb *inp;
826 	int s;
827 
828 	inp = sotoinpcb(so);
829 	if (inp == 0)
830 		return EINVAL;	/* ??? possible? panic instead? */
831 	soisdisconnected(so);
832 	s = splnet();
833 	in_pcbdetach(inp);
834 	splx(s);
835 	return 0;
836 }
837 
838 static int
839 udp_attach(struct socket *so, int proto, struct pru_attach_info *ai)
840 {
841 	struct inpcb *inp;
842 	int s, error;
843 
844 	inp = sotoinpcb(so);
845 	if (inp != 0)
846 		return EINVAL;
847 
848 	error = soreserve(so, udp_sendspace, udp_recvspace, ai->sb_rlimit);
849 	if (error)
850 		return error;
851 	s = splnet();
852 	error = in_pcballoc(so, &udbinfo);
853 	splx(s);
854 	if (error)
855 		return error;
856 
857 	inp = (struct inpcb *)so->so_pcb;
858 	inp->inp_vflag |= INP_IPV4;
859 	inp->inp_ip_ttl = ip_defttl;
860 	return 0;
861 }
862 
863 static int
864 udp_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
865 {
866 	struct sockaddr_in *sin = (struct sockaddr_in *)nam;
867 	struct inpcb *inp;
868 	int s, error;
869 
870 	inp = sotoinpcb(so);
871 	if (inp == 0)
872 		return EINVAL;
873 	s = splnet();
874 	error = in_pcbbind(inp, nam, td);
875 	splx(s);
876 	if (error == 0) {
877 		if (sin->sin_addr.s_addr != INADDR_ANY)
878 			inp->inp_flags |= INP_WASBOUND_NOTANY;
879 		in_pcbinswildcardhash(inp);
880 	}
881 	return error;
882 }
883 
884 static int
885 udp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
886 {
887 	struct inpcb *inp;
888 	int s, error;
889 	struct sockaddr_in *sin;
890 
891 	inp = sotoinpcb(so);
892 	if (inp == 0)
893 		return EINVAL;
894 	if (inp->inp_faddr.s_addr != INADDR_ANY)
895 		return EISCONN;
896 	error = 0;
897 	s = splnet();
898 	if (td->td_proc && td->td_proc->p_ucred->cr_prison != NULL &&
899 	    inp->inp_laddr.s_addr == INADDR_ANY) {
900 		error = in_pcbbind(inp, NULL, td);
901 	}
902 	if (error == 0) {
903 		sin = (struct sockaddr_in *)nam;
904 		prison_remote_ip(td, 0, &sin->sin_addr.s_addr);
905 		if (inp->inp_flags & INP_WILDCARD)
906 			in_pcbremwildcardhash(inp);
907 		error = in_pcbconnect(inp, nam, td);
908 	}
909 	splx(s);
910 	if (error == 0)
911 		soisconnected(so);
912 	else if (error == EAFNOSUPPORT) {	/* connection dissolved */
913 		/*
914 		 * Follow traditional BSD behavior and retain
915 		 * the local port binding.  But, fix the old misbehavior
916 		 * of overwriting any previously bound local address.
917 		 */
918 		if (!(inp->inp_flags & INP_WASBOUND_NOTANY))
919 			inp->inp_laddr.s_addr = INADDR_ANY;
920 		in_pcbinswildcardhash(inp);
921 	}
922 	return error;
923 }
924 
925 static int
926 udp_detach(struct socket *so)
927 {
928 	struct inpcb *inp;
929 	int s;
930 
931 	inp = sotoinpcb(so);
932 	if (inp == 0)
933 		return EINVAL;
934 	s = splnet();
935 	in_pcbdetach(inp);
936 	splx(s);
937 	return 0;
938 }
939 
940 static int
941 udp_disconnect(struct socket *so)
942 {
943 	struct inpcb *inp;
944 	int s;
945 
946 	inp = sotoinpcb(so);
947 	if (inp == 0)
948 		return EINVAL;
949 	if (inp->inp_faddr.s_addr == INADDR_ANY)
950 		return ENOTCONN;
951 
952 	s = splnet();
953 	in_pcbdisconnect(inp);
954 	splx(s);
955 	so->so_state &= ~SS_ISCONNECTED;		/* XXX */
956 	return 0;
957 }
958 
959 static int
960 udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
961 	    struct mbuf *control, struct thread *td)
962 {
963 	struct inpcb *inp;
964 
965 	inp = sotoinpcb(so);
966 	if (inp == 0) {
967 		m_freem(m);
968 		return EINVAL;
969 	}
970 	return udp_output(inp, m, addr, control, td);
971 }
972 
973 int
974 udp_shutdown(struct socket *so)
975 {
976 	struct inpcb *inp;
977 
978 	inp = sotoinpcb(so);
979 	if (inp == 0)
980 		return EINVAL;
981 	socantsendmore(so);
982 	return 0;
983 }
984 
985 struct pr_usrreqs udp_usrreqs = {
986 	udp_abort, pru_accept_notsupp, udp_attach, udp_bind, udp_connect,
987 	pru_connect2_notsupp, in_control, udp_detach, udp_disconnect,
988 	pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp,
989 	pru_rcvoob_notsupp, udp_send, pru_sense_null, udp_shutdown,
990 	in_setsockaddr, sosendudp, soreceive, sopoll
991 };
992 
993