sys/netinet/udp_usrreq.c

   1 /*-
   2  * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
   3  *      The Regents of the University of California.
   4  * 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  * 4. 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        8.6 (Berkeley) 5/23/95
  31  * $FreeBSD$
  32  */
  33
  34 #include "opt_ipfw.h"
  35 #include "opt_ipsec.h"
  36 #include "opt_inet6.h"
  37 #include "opt_mac.h"
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/domain.h>
  42 #include <sys/eventhandler.h>
  43 #include <sys/jail.h>
  44 #include <sys/kernel.h>
  45 #include <sys/lock.h>
  46 #include <sys/malloc.h>
  47 #include <sys/mbuf.h>
  48 #include <sys/priv.h>
  49 #include <sys/proc.h>
  50 #include <sys/protosw.h>
  51 #include <sys/signalvar.h>
  52 #include <sys/socket.h>
  53 #include <sys/socketvar.h>
  54 #include <sys/sx.h>
  55 #include <sys/sysctl.h>
  56 #include <sys/syslog.h>
  57
  58 #include <vm/uma.h>
  59
  60 #include <net/if.h>
  61 #include <net/route.h>
  62
  63 #include <netinet/in.h>
  64 #include <netinet/in_systm.h>
  65 #include <netinet/in_pcb.h>
  66 #include <netinet/in_var.h>
  67 #include <netinet/ip.h>
  68 #ifdef INET6
  69 #include <netinet/ip6.h>
  70 #endif
  71 #include <netinet/ip_icmp.h>
  72 #include <netinet/icmp_var.h>
  73 #include <netinet/ip_var.h>
  74 #include <netinet/ip_options.h>
  75 #ifdef INET6
  76 #include <netinet6/ip6_var.h>
  77 #endif
  78 #include <netinet/udp.h>
  79 #include <netinet/udp_var.h>
  80
  81 #ifdef FAST_IPSEC
  82 #include <netipsec/ipsec.h>
  83 #endif
  84
  85 #ifdef IPSEC
  86 #include <netinet6/ipsec.h>
  87 #endif
  88
  89 #include <machine/in_cksum.h>
  90
  91 #include <security/mac/mac_framework.h>
  92
  93 /*
  94  * UDP protocol implementation.
  95  * Per RFC 768, August, 1980.
  96  */
  97
  98 /*
  99  * BSD 4.2 defaulted the udp checksum to be off.  Turning off udp checksums
 100  * removes the only data integrity mechanism for packets and malformed
 101  * packets that would otherwise be discarded by bad checksums may cause
 102  * problems (especially for NFS data blocks).
 103  */
 104 static int      udpcksum = 1;
 105 SYSCTL_INT(_net_inet_udp, UDPCTL_CHECKSUM, checksum, CTLFLAG_RW, &udpcksum,
 106     0, "");
 107
 108 int     udp_log_in_vain = 0;
 109 SYSCTL_INT(_net_inet_udp, OID_AUTO, log_in_vain, CTLFLAG_RW,
 110     &udp_log_in_vain, 0, "Log all incoming UDP packets");
 111
 112 static int      blackhole = 0;
 113 SYSCTL_INT(_net_inet_udp, OID_AUTO, blackhole, CTLFLAG_RW, &blackhole, 0,
 114     "Do not send port unreachables for refused connects");
 115
 116 static int      strict_mcast_mship = 0;
 117 SYSCTL_INT(_net_inet_udp, OID_AUTO, strict_mcast_mship, CTLFLAG_RW,
 118     &strict_mcast_mship, 0, "Only send multicast to member sockets");
 119
 120 struct  inpcbhead udb;          /* from udp_var.h */
 121 struct  inpcbinfo udbinfo;
 122
 123 #ifndef UDBHASHSIZE
 124 #define UDBHASHSIZE 16
 125 #endif
 126
 127 struct  udpstat udpstat;        /* from udp_var.h */
 128 SYSCTL_STRUCT(_net_inet_udp, UDPCTL_STATS, stats, CTLFLAG_RW, &udpstat,
 129     udpstat, "UDP statistics (struct udpstat, netinet/udp_var.h)");
 130
 131 static void     udp_append(struct inpcb *last, struct ip *ip, struct mbuf *n,
 132                     int off, struct sockaddr_in *udp_in);
 133
 134 static void     udp_detach(struct socket *so);
 135 static int      udp_output(struct inpcb *, struct mbuf *, struct sockaddr *,
 136                     struct mbuf *, struct thread *);
 137
 138 static void
 139 udp_zone_change(void *tag)
 140 {
 141
 142         uma_zone_set_max(udbinfo.ipi_zone, maxsockets);
 143 }
 144
 145 static int
 146 udp_inpcb_init(void *mem, int size, int flags)
 147 {
 148         struct inpcb *inp = mem;
 149
 150         INP_LOCK_INIT(inp, "inp", "udpinp");
 151         return (0);
 152 }
 153
 154 void
 155 udp_init()
 156 {
 157         INP_INFO_LOCK_INIT(&udbinfo, "udp");
 158         LIST_INIT(&udb);
 159         udbinfo.listhead = &udb;
 160         udbinfo.hashbase = hashinit(UDBHASHSIZE, M_PCB, &udbinfo.hashmask);
 161         udbinfo.porthashbase = hashinit(UDBHASHSIZE, M_PCB,
 162             &udbinfo.porthashmask);
 163         udbinfo.ipi_zone = uma_zcreate("udpcb", sizeof(struct inpcb), NULL,
 164             NULL, udp_inpcb_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
 165         uma_zone_set_max(udbinfo.ipi_zone, maxsockets);
 166         EVENTHANDLER_REGISTER(maxsockets_change, udp_zone_change, NULL,
 167                 EVENTHANDLER_PRI_ANY);
 168 }
 169
 170 void
 171 udp_input(struct mbuf *m, int off)
 172 {
 173         int iphlen = off;
 174         struct ip *ip;
 175         struct udphdr *uh;
 176         struct inpcb *inp;
 177         int len;
 178         struct ip save_ip;
 179         struct sockaddr_in udp_in;
 180 #ifdef IPFIREWALL_FORWARD
 181         struct m_tag *fwd_tag;
 182 #endif
 183
 184         udpstat.udps_ipackets++;
 185
 186         /*
 187          * Strip IP options, if any; should skip this, make available to
 188          * user, and use on returned packets, but we don't yet have a way to
 189          * check the checksum with options still present.
 190          */
 191         if (iphlen > sizeof (struct ip)) {
 192                 ip_stripoptions(m, (struct mbuf *)0);
 193                 iphlen = sizeof(struct ip);
 194         }
 195
 196         /*
 197          * Get IP and UDP header together in first mbuf.
 198          */
 199         ip = mtod(m, struct ip *);
 200         if (m->m_len < iphlen + sizeof(struct udphdr)) {
 201                 if ((m = m_pullup(m, iphlen + sizeof(struct udphdr))) == 0) {
 202                         udpstat.udps_hdrops++;
 203                         return;
 204                 }
 205                 ip = mtod(m, struct ip *);
 206         }
 207         uh = (struct udphdr *)((caddr_t)ip + iphlen);
 208
 209         /*
 210          * Destination port of 0 is illegal, based on RFC768.
 211          */
 212         if (uh->uh_dport == 0)
 213                 goto badunlocked;
 214
 215         /*
 216          * Construct sockaddr format source address.  Stuff source address
 217          * and datagram in user buffer.
 218          */
 219         bzero(&udp_in, sizeof(udp_in));
 220         udp_in.sin_len = sizeof(udp_in);
 221         udp_in.sin_family = AF_INET;
 222         udp_in.sin_port = uh->uh_sport;
 223         udp_in.sin_addr = ip->ip_src;
 224
 225         /*
 226          * Make mbuf data length reflect UDP length.
 227          * If not enough data to reflect UDP length, drop.
 228          */
 229         len = ntohs((u_short)uh->uh_ulen);
 230         if (ip->ip_len != len) {
 231                 if (len > ip->ip_len || len < sizeof(struct udphdr)) {
 232                         udpstat.udps_badlen++;
 233                         goto badunlocked;
 234                 }
 235                 m_adj(m, len - ip->ip_len);
 236                 /* ip->ip_len = len; */
 237         }
 238
 239         /*
 240          * Save a copy of the IP header in case we want restore it for
 241          * sending an ICMP error message in response.
 242          */
 243         if (!blackhole)
 244                 save_ip = *ip;
 245
 246         /*
 247          * Checksum extended UDP header and data.
 248          */
 249         if (uh->uh_sum) {
 250                 if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
 251                         if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
 252                                 uh->uh_sum = m->m_pkthdr.csum_data;
 253                         else
 254                                 uh->uh_sum = in_pseudo(ip->ip_src.s_addr,
 255                                     ip->ip_dst.s_addr, htonl((u_short)len +
 256                                     m->m_pkthdr.csum_data + IPPROTO_UDP));
 257                         uh->uh_sum ^= 0xffff;
 258                 } else {
 259                         char b[9];
 260                         bcopy(((struct ipovly *)ip)->ih_x1, b, 9);
 261                         bzero(((struct ipovly *)ip)->ih_x1, 9);
 262                         ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
 263                         uh->uh_sum = in_cksum(m, len + sizeof (struct ip));
 264                         bcopy(b, ((struct ipovly *)ip)->ih_x1, 9);
 265                 }
 266                 if (uh->uh_sum) {
 267                         udpstat.udps_badsum++;
 268                         m_freem(m);
 269                         return;
 270                 }
 271         } else
 272                 udpstat.udps_nosum++;
 273
 274 #ifdef IPFIREWALL_FORWARD
 275         /*
 276          * Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
 277          */
 278         fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
 279         if (fwd_tag != NULL) {
 280                 struct sockaddr_in *next_hop;
 281
 282                 /*
 283                  * Do the hack.
 284                  */
 285                 next_hop = (struct sockaddr_in *)(fwd_tag + 1);
 286                 ip->ip_dst = next_hop->sin_addr;
 287                 uh->uh_dport = ntohs(next_hop->sin_port);
 288
 289                 /*
 290                  * Remove the tag from the packet.  We don't need it anymore.
 291                  */
 292                 m_tag_delete(m, fwd_tag);
 293         }
 294 #endif
 295
 296         INP_INFO_RLOCK(&udbinfo);
 297
 298         if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
 299             in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) {
 300                 struct inpcb *last;
 301
 302                 /*
 303                  * Deliver a multicast or broadcast datagram to *all* sockets
 304                  * for which the local and remote addresses and ports match
 305                  * those of the incoming datagram.  This allows more than one
 306                  * process to receive multi/broadcasts on the same port.
 307                  * (This really ought to be done for unicast datagrams as
 308                  * well, but that would cause problems with existing
 309                  * applications that open both address-specific sockets and a
 310                  * wildcard socket listening to the same port -- they would
 311                  * end up receiving duplicates of every unicast datagram.
 312                  * Those applications open the multiple sockets to overcome
 313                  * an inadequacy of the UDP socket interface, but for
 314                  * backwards compatibility we avoid the problem here rather
 315                  * than fixing the interface.  Maybe 4.5BSD will remedy
 316                  * this?)
 317                  */
 318                 last = NULL;
 319                 LIST_FOREACH(inp, &udb, inp_list) {
 320                         if (inp->inp_lport != uh->uh_dport)
 321                                 continue;
 322 #ifdef INET6
 323                         if ((inp->inp_vflag & INP_IPV4) == 0)
 324                                 continue;
 325 #endif
 326                         if (inp->inp_laddr.s_addr != INADDR_ANY) {
 327                                 if (inp->inp_laddr.s_addr != ip->ip_dst.s_addr)
 328                                         continue;
 329                         }
 330                         if (inp->inp_faddr.s_addr != INADDR_ANY) {
 331                                 if (inp->inp_faddr.s_addr !=
 332                                     ip->ip_src.s_addr ||
 333                                     inp->inp_fport != uh->uh_sport)
 334                                         continue;
 335                         }
 336
 337                         /*
 338                          * Check multicast packets to make sure they are only
 339                          * sent to sockets with multicast memberships for the
 340                          * packet's destination address and arrival interface
 341                          */
 342 #define MSHIP(_inp, n) ((_inp)->inp_moptions->imo_membership[(n)])
 343 #define NMSHIPS(_inp) ((_inp)->inp_moptions->imo_num_memberships)
 344                         INP_LOCK(inp);
 345                         if (strict_mcast_mship && inp->inp_moptions != NULL) {
 346                                 int mship, foundmship = 0;
 347
 348                                 for (mship = 0; mship < NMSHIPS(inp);
 349                                     mship++) {
 350                                         if (MSHIP(inp, mship)->inm_addr.s_addr
 351                                             == ip->ip_dst.s_addr &&
 352                                             MSHIP(inp, mship)->inm_ifp
 353                                             == m->m_pkthdr.rcvif) {
 354                                                 foundmship = 1;
 355                                                 break;
 356                                         }
 357                                 }
 358                                 if (foundmship == 0) {
 359                                         INP_UNLOCK(inp);
 360                                         continue;
 361                                 }
 362                         }
 363 #undef NMSHIPS
 364 #undef MSHIP
 365                         if (last != NULL) {
 366                                 struct mbuf *n;
 367
 368                                 n = m_copy(m, 0, M_COPYALL);
 369                                 if (n != NULL)
 370                                         udp_append(last, ip, n, iphlen +
 371                                             sizeof(struct udphdr), &udp_in);
 372                                 INP_UNLOCK(last);
 373                         }
 374                         last = inp;
 375                         /*
 376                          * Don't look for additional matches if this one does
 377                          * not have either the SO_REUSEPORT or SO_REUSEADDR
 378                          * socket options set.  This heuristic avoids
 379                          * searching through all pcbs in the common case of a
 380                          * non-shared port.  It assumes that an application
 381                          * will never clear these options after setting them.
 382                          */
 383                         if ((last->inp_socket->so_options &
 384                             (SO_REUSEPORT|SO_REUSEADDR)) == 0)
 385                                 break;
 386                 }
 387
 388                 if (last == NULL) {
 389                         /*
 390                          * No matching pcb found; discard datagram.  (No need
 391                          * to send an ICMP Port Unreachable for a broadcast
 392                          * or multicast datgram.)
 393                          */
 394                         udpstat.udps_noportbcast++;
 395                         goto badheadlocked;
 396                 }
 397                 udp_append(last, ip, m, iphlen + sizeof(struct udphdr),
 398                     &udp_in);
 399                 INP_UNLOCK(last);
 400                 INP_INFO_RUNLOCK(&udbinfo);
 401                 return;
 402         }
 403
 404         /*
 405          * Locate pcb for datagram.
 406          */
 407         inp = in_pcblookup_hash(&udbinfo, ip->ip_src, uh->uh_sport,
 408             ip->ip_dst, uh->uh_dport, 1, m->m_pkthdr.rcvif);
 409         if (inp == NULL) {
 410                 if (udp_log_in_vain) {
 411                         char buf[4*sizeof "123"];
 412
 413                         strcpy(buf, inet_ntoa(ip->ip_dst));
 414                         log(LOG_INFO,
 415                             "Connection attempt to UDP %s:%d from %s:%d\n",
 416                             buf, ntohs(uh->uh_dport), inet_ntoa(ip->ip_src),
 417                             ntohs(uh->uh_sport));
 418                 }
 419                 udpstat.udps_noport++;
 420                 if (m->m_flags & (M_BCAST | M_MCAST)) {
 421                         udpstat.udps_noportbcast++;
 422                         goto badheadlocked;
 423                 }
 424                 if (blackhole)
 425                         goto badheadlocked;
 426                 if (badport_bandlim(BANDLIM_ICMP_UNREACH) < 0)
 427                         goto badheadlocked;
 428                 *ip = save_ip;
 429                 ip->ip_len += iphlen;
 430                 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0);
 431                 INP_INFO_RUNLOCK(&udbinfo);
 432                 return;
 433         }
 434
 435         /*
 436          * Check the minimum TTL for socket.
 437          */
 438         INP_LOCK(inp);
 439         if (inp->inp_ip_minttl && inp->inp_ip_minttl > ip->ip_ttl)
 440                 goto badheadlocked;
 441         udp_append(inp, ip, m, iphlen + sizeof(struct udphdr), &udp_in);
 442         INP_UNLOCK(inp);
 443         INP_INFO_RUNLOCK(&udbinfo);
 444         return;
 445
 446 badheadlocked:
 447         if (inp)
 448                 INP_UNLOCK(inp);
 449         INP_INFO_RUNLOCK(&udbinfo);
 450 badunlocked:
 451         m_freem(m);
 452 }
 453
 454 /*
 455  * Subroutine of udp_input(), which appends the provided mbuf chain to the
 456  * passed pcb/socket.  The caller must provide a sockaddr_in via udp_in that
 457  * contains the source address.  If the socket ends up being an IPv6 socket,
 458  * udp_append() will convert to a sockaddr_in6 before passing the address
 459  * into the socket code.
 460  */
 461 static void
 462 udp_append(struct inpcb *inp, struct ip *ip, struct mbuf *n, int off,
 463     struct sockaddr_in *udp_in)
 464 {
 465         struct sockaddr *append_sa;
 466         struct socket *so;
 467         struct mbuf *opts = 0;
 468 #ifdef INET6
 469         struct sockaddr_in6 udp_in6;
 470 #endif
 471
 472         INP_LOCK_ASSERT(inp);
 473
 474 #if defined(IPSEC) || defined(FAST_IPSEC)
 475         /* check AH/ESP integrity. */
 476         if (ipsec4_in_reject(n, inp)) {
 477 #ifdef IPSEC
 478                 ipsecstat.in_polvio++;
 479 #endif
 480                 m_freem(n);
 481                 return;
 482         }
 483 #endif /*IPSEC || FAST_IPSEC*/
 484 #ifdef MAC
 485         if (mac_check_inpcb_deliver(inp, n) != 0) {
 486                 m_freem(n);
 487                 return;
 488         }
 489 #endif
 490         if (inp->inp_flags & INP_CONTROLOPTS ||
 491             inp->inp_socket->so_options & (SO_TIMESTAMP | SO_BINTIME)) {
 492 #ifdef INET6
 493                 if (inp->inp_vflag & INP_IPV6) {
 494                         int savedflags;
 495
 496                         savedflags = inp->inp_flags;
 497                         inp->inp_flags &= ~INP_UNMAPPABLEOPTS;
 498                         ip6_savecontrol(inp, n, &opts);
 499                         inp->inp_flags = savedflags;
 500                 } else
 501 #endif
 502                         ip_savecontrol(inp, &opts, ip, n);
 503         }
 504 #ifdef INET6
 505         if (inp->inp_vflag & INP_IPV6) {
 506                 bzero(&udp_in6, sizeof(udp_in6));
 507                 udp_in6.sin6_len = sizeof(udp_in6);
 508                 udp_in6.sin6_family = AF_INET6;
 509                 in6_sin_2_v4mapsin6(udp_in, &udp_in6);
 510                 append_sa = (struct sockaddr *)&udp_in6;
 511         } else
 512 #endif
 513                 append_sa = (struct sockaddr *)udp_in;
 514         m_adj(n, off);
 515
 516         so = inp->inp_socket;
 517         SOCKBUF_LOCK(&so->so_rcv);
 518         if (sbappendaddr_locked(&so->so_rcv, append_sa, n, opts) == 0) {
 519                 m_freem(n);
 520                 if (opts)
 521                         m_freem(opts);
 522                 udpstat.udps_fullsock++;
 523                 SOCKBUF_UNLOCK(&so->so_rcv);
 524         } else
 525                 sorwakeup_locked(so);
 526 }
 527
 528 /*
 529  * Notify a udp user of an asynchronous error; just wake up so that they can
 530  * collect error status.
 531  */
 532 struct inpcb *
 533 udp_notify(struct inpcb *inp, int errno)
 534 {
 535
 536         inp->inp_socket->so_error = errno;
 537         sorwakeup(inp->inp_socket);
 538         sowwakeup(inp->inp_socket);
 539         return (inp);
 540 }
 541
 542 void
 543 udp_ctlinput(int cmd, struct sockaddr *sa, void *vip)
 544 {
 545         struct ip *ip = vip;
 546         struct udphdr *uh;
 547         struct inpcb *(*notify)(struct inpcb *, int) = udp_notify;
 548         struct in_addr faddr;
 549         struct inpcb *inp;
 550
 551         faddr = ((struct sockaddr_in *)sa)->sin_addr;
 552         if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
 553                 return;
 554
 555         /*
 556          * Redirects don't need to be handled up here.
 557          */
 558         if (PRC_IS_REDIRECT(cmd))
 559                 return;
 560
 561         /*
 562          * Hostdead is ugly because it goes linearly through all PCBs.
 563          *
 564          * XXX: We never get this from ICMP, otherwise it makes an excellent
 565          * DoS attack on machines with many connections.
 566          */
 567         if (cmd == PRC_HOSTDEAD)
 568                 ip = 0;
 569         else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
 570                 return;
 571         if (ip) {
 572                 uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2));
 573                 INP_INFO_RLOCK(&udbinfo);
 574                 inp = in_pcblookup_hash(&udbinfo, faddr, uh->uh_dport,
 575                     ip->ip_src, uh->uh_sport, 0, NULL);
 576                 if (inp != NULL) {
 577                         INP_LOCK(inp);
 578                         if (inp->inp_socket != NULL) {
 579                                 (*notify)(inp, inetctlerrmap[cmd]);
 580                         }
 581                         INP_UNLOCK(inp);
 582                 }
 583                 INP_INFO_RUNLOCK(&udbinfo);
 584         } else
 585                 in_pcbnotifyall(&udbinfo, faddr, inetctlerrmap[cmd], notify);
 586 }
 587
 588 static int
 589 udp_pcblist(SYSCTL_HANDLER_ARGS)
 590 {
 591         int error, i, n;
 592         struct inpcb *inp, **inp_list;
 593         inp_gen_t gencnt;
 594         struct xinpgen xig;
 595
 596         /*
 597          * The process of preparing the TCB list is too time-consuming and
 598          * resource-intensive to repeat twice on every request.
 599          */
 600         if (req->oldptr == 0) {
 601                 n = udbinfo.ipi_count;
 602                 req->oldidx = 2 * (sizeof xig)
 603                         + (n + n/8) * sizeof(struct xinpcb);
 604                 return (0);
 605         }
 606
 607         if (req->newptr != 0)
 608                 return (EPERM);
 609
 610         /*
 611          * OK, now we're committed to doing something.
 612          */
 613         INP_INFO_RLOCK(&udbinfo);
 614         gencnt = udbinfo.ipi_gencnt;
 615         n = udbinfo.ipi_count;
 616         INP_INFO_RUNLOCK(&udbinfo);
 617
 618         error = sysctl_wire_old_buffer(req, 2 * (sizeof xig)
 619                 + n * sizeof(struct xinpcb));
 620         if (error != 0)
 621                 return (error);
 622
 623         xig.xig_len = sizeof xig;
 624         xig.xig_count = n;
 625         xig.xig_gen = gencnt;
 626         xig.xig_sogen = so_gencnt;
 627         error = SYSCTL_OUT(req, &xig, sizeof xig);
 628         if (error)
 629                 return (error);
 630
 631         inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
 632         if (inp_list == 0)
 633                 return (ENOMEM);
 634
 635         INP_INFO_RLOCK(&udbinfo);
 636         for (inp = LIST_FIRST(udbinfo.listhead), i = 0; inp && i < n;
 637              inp = LIST_NEXT(inp, inp_list)) {
 638                 INP_LOCK(inp);
 639                 if (inp->inp_gencnt <= gencnt &&
 640                     cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0)
 641                         inp_list[i++] = inp;
 642                 INP_UNLOCK(inp);
 643         }
 644         INP_INFO_RUNLOCK(&udbinfo);
 645         n = i;
 646
 647         error = 0;
 648         for (i = 0; i < n; i++) {
 649                 inp = inp_list[i];
 650                 INP_LOCK(inp);
 651                 if (inp->inp_gencnt <= gencnt) {
 652                         struct xinpcb xi;
 653                         bzero(&xi, sizeof(xi));
 654                         xi.xi_len = sizeof xi;
 655                         /* XXX should avoid extra copy */
 656                         bcopy(inp, &xi.xi_inp, sizeof *inp);
 657                         if (inp->inp_socket)
 658                                 sotoxsocket(inp->inp_socket, &xi.xi_socket);
 659                         xi.xi_inp.inp_gencnt = inp->inp_gencnt;
 660                         INP_UNLOCK(inp);
 661                         error = SYSCTL_OUT(req, &xi, sizeof xi);
 662                 } else
 663                         INP_UNLOCK(inp);
 664         }
 665         if (!error) {
 666                 /*
 667                  * Give the user an updated idea of our state.  If the
 668                  * generation differs from what we told her before, she knows
 669                  * that something happened while we were processing this
 670                  * request, and it might be necessary to retry.
 671                  */
 672                 INP_INFO_RLOCK(&udbinfo);
 673                 xig.xig_gen = udbinfo.ipi_gencnt;
 674                 xig.xig_sogen = so_gencnt;
 675                 xig.xig_count = udbinfo.ipi_count;
 676                 INP_INFO_RUNLOCK(&udbinfo);
 677                 error = SYSCTL_OUT(req, &xig, sizeof xig);
 678         }
 679         free(inp_list, M_TEMP);
 680         return (error);
 681 }
 682
 683 SYSCTL_PROC(_net_inet_udp, UDPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
 684     udp_pcblist, "S,xinpcb", "List of active UDP sockets");
 685
 686 static int
 687 udp_getcred(SYSCTL_HANDLER_ARGS)
 688 {
 689         struct xucred xuc;
 690         struct sockaddr_in addrs[2];
 691         struct inpcb *inp;
 692         int error;
 693
 694         error = priv_check_cred(req->td->td_ucred, PRIV_NETINET_GETCRED,
 695             SUSER_ALLOWJAIL);
 696         if (error)
 697                 return (error);
 698         error = SYSCTL_IN(req, addrs, sizeof(addrs));
 699         if (error)
 700                 return (error);
 701         INP_INFO_RLOCK(&udbinfo);
 702         inp = in_pcblookup_hash(&udbinfo, addrs[1].sin_addr, addrs[1].sin_port,
 703                                 addrs[0].sin_addr, addrs[0].sin_port, 1, NULL);
 704         if (inp == NULL || inp->inp_socket == NULL) {
 705                 error = ENOENT;
 706                 goto out;
 707         }
 708         error = cr_canseesocket(req->td->td_ucred, inp->inp_socket);
 709         if (error)
 710                 goto out;
 711         cru2x(inp->inp_socket->so_cred, &xuc);
 712 out:
 713         INP_INFO_RUNLOCK(&udbinfo);
 714         if (error == 0)
 715                 error = SYSCTL_OUT(req, &xuc, sizeof(struct xucred));
 716         return (error);
 717 }
 718
 719 SYSCTL_PROC(_net_inet_udp, OID_AUTO, getcred,
 720     CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_PRISON, 0, 0,
 721     udp_getcred, "S,xucred", "Get the xucred of a UDP connection");
 722
 723 static int
 724 udp_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr,
 725     struct mbuf *control, struct thread *td)
 726 {
 727         struct udpiphdr *ui;
 728         int len = m->m_pkthdr.len;
 729         struct in_addr faddr, laddr;
 730         struct cmsghdr *cm;
 731         struct sockaddr_in *sin, src;
 732         int error = 0;
 733         int ipflags;
 734         u_short fport, lport;
 735         int unlock_udbinfo;
 736
 737         /*
 738          * udp_output() may need to temporarily bind or connect the current
 739          * inpcb.  As such, we don't know up front what inpcb locks we will
 740          * need.  Do any work to decide what is needed up front before
 741          * acquiring locks.
 742          */
 743         if (len + sizeof(struct udpiphdr) > IP_MAXPACKET) {
 744                 if (control)
 745                         m_freem(control);
 746                 m_freem(m);
 747                 return (EMSGSIZE);
 748         }
 749
 750         src.sin_family = 0;
 751         if (control != NULL) {
 752                 /*
 753                  * XXX: Currently, we assume all the optional information is
 754                  * stored in a single mbuf.
 755                  */
 756                 if (control->m_next) {
 757                         m_freem(control);
 758                         m_freem(m);
 759                         return (EINVAL);
 760                 }
 761                 for (; control->m_len > 0;
 762                     control->m_data += CMSG_ALIGN(cm->cmsg_len),
 763                     control->m_len -= CMSG_ALIGN(cm->cmsg_len)) {
 764                         cm = mtod(control, struct cmsghdr *);
 765                         if (control->m_len < sizeof(*cm) || cm->cmsg_len == 0 ||
 766                             cm->cmsg_len > control->m_len) {
 767                                 error = EINVAL;
 768                                 break;
 769                         }
 770                         if (cm->cmsg_level != IPPROTO_IP)
 771                                 continue;
 772
 773                         switch (cm->cmsg_type) {
 774                         case IP_SENDSRCADDR:
 775                                 if (cm->cmsg_len !=
 776                                     CMSG_LEN(sizeof(struct in_addr))) {
 777                                         error = EINVAL;
 778                                         break;
 779                                 }
 780                                 bzero(&src, sizeof(src));
 781                                 src.sin_family = AF_INET;
 782                                 src.sin_len = sizeof(src);
 783                                 src.sin_port = inp->inp_lport;
 784                                 src.sin_addr = *(struct in_addr *)CMSG_DATA(cm);
 785                                 break;
 786                         default:
 787                                 error = ENOPROTOOPT;
 788                                 break;
 789                         }
 790                         if (error)
 791                                 break;
 792                 }
 793                 m_freem(control);
 794         }
 795         if (error) {
 796                 m_freem(m);
 797                 return (error);
 798         }
 799
 800         if (src.sin_family == AF_INET || addr != NULL) {
 801                 INP_INFO_WLOCK(&udbinfo);
 802                 unlock_udbinfo = 1;
 803         } else
 804                 unlock_udbinfo = 0;
 805         INP_LOCK(inp);
 806
 807 #ifdef MAC
 808         mac_create_mbuf_from_inpcb(inp, m);
 809 #endif
 810
 811         /*
 812          * If the IP_SENDSRCADDR control message was specified, override the
 813          * source address for this datagram. Its use is invalidated if the
 814          * address thus specified is incomplete or clobbers other inpcbs.
 815          */
 816         laddr = inp->inp_laddr;
 817         lport = inp->inp_lport;
 818         if (src.sin_family == AF_INET) {
 819                 if ((lport == 0) ||
 820                     (laddr.s_addr == INADDR_ANY &&
 821                      src.sin_addr.s_addr == INADDR_ANY)) {
 822                         error = EINVAL;
 823                         goto release;
 824                 }
 825                 error = in_pcbbind_setup(inp, (struct sockaddr *)&src,
 826                     &laddr.s_addr, &lport, td->td_ucred);
 827                 if (error)
 828                         goto release;
 829         }
 830
 831         if (addr) {
 832                 sin = (struct sockaddr_in *)addr;
 833                 if (jailed(td->td_ucred))
 834                         prison_remote_ip(td->td_ucred, 0,
 835                             &sin->sin_addr.s_addr);
 836                 if (inp->inp_faddr.s_addr != INADDR_ANY) {
 837                         error = EISCONN;
 838                         goto release;
 839                 }
 840                 error = in_pcbconnect_setup(inp, addr, &laddr.s_addr, &lport,
 841                     &faddr.s_addr, &fport, NULL, td->td_ucred);
 842                 if (error)
 843                         goto release;
 844
 845                 /* Commit the local port if newly assigned. */
 846                 if (inp->inp_laddr.s_addr == INADDR_ANY &&
 847                     inp->inp_lport == 0) {
 848                         /*
 849                          * Remember addr if jailed, to prevent rebinding.
 850                          */
 851                         if (jailed(td->td_ucred))
 852                                 inp->inp_laddr = laddr;
 853                         inp->inp_lport = lport;
 854                         if (in_pcbinshash(inp) != 0) {
 855                                 inp->inp_lport = 0;
 856                                 error = EAGAIN;
 857                                 goto release;
 858                         }
 859                         inp->inp_flags |= INP_ANONPORT;
 860                 }
 861         } else {
 862                 faddr = inp->inp_faddr;
 863                 fport = inp->inp_fport;
 864                 if (faddr.s_addr == INADDR_ANY) {
 865                         error = ENOTCONN;
 866                         goto release;
 867                 }
 868         }
 869
 870         /*
 871          * Calculate data length and get a mbuf for UDP, IP, and possible
 872          * link-layer headers.  Immediate slide the data pointer back forward
 873          * since we won't use that space at this layer.
 874          */
 875         M_PREPEND(m, sizeof(struct udpiphdr) + max_linkhdr, M_DONTWAIT);
 876         if (m == NULL) {
 877                 error = ENOBUFS;
 878                 goto release;
 879         }
 880         m->m_data += max_linkhdr;
 881         m->m_len -= max_linkhdr;
 882         m->m_pkthdr.len -= max_linkhdr;
 883
 884         /*
 885          * Fill in mbuf with extended UDP header and addresses and length put
 886          * into network format.
 887          */
 888         ui = mtod(m, struct udpiphdr *);
 889         bzero(ui->ui_x1, sizeof(ui->ui_x1));    /* XXX still needed? */
 890         ui->ui_pr = IPPROTO_UDP;
 891         ui->ui_src = laddr;
 892         ui->ui_dst = faddr;
 893         ui->ui_sport = lport;
 894         ui->ui_dport = fport;
 895         ui->ui_ulen = htons((u_short)len + sizeof(struct udphdr));
 896
 897         /*
 898          * Set the Don't Fragment bit in the IP header.
 899          */
 900         if (inp->inp_flags & INP_DONTFRAG) {
 901                 struct ip *ip;
 902
 903                 ip = (struct ip *)&ui->ui_i;
 904                 ip->ip_off |= IP_DF;
 905         }
 906
 907         ipflags = 0;
 908         if (inp->inp_socket->so_options & SO_DONTROUTE)
 909                 ipflags |= IP_ROUTETOIF;
 910         if (inp->inp_socket->so_options & SO_BROADCAST)
 911                 ipflags |= IP_ALLOWBROADCAST;
 912         if (inp->inp_flags & INP_ONESBCAST)
 913                 ipflags |= IP_SENDONES;
 914
 915         /*
 916          * Set up checksum and output datagram.
 917          */
 918         if (udpcksum) {
 919                 if (inp->inp_flags & INP_ONESBCAST)
 920                         faddr.s_addr = INADDR_BROADCAST;
 921                 ui->ui_sum = in_pseudo(ui->ui_src.s_addr, faddr.s_addr,
 922                     htons((u_short)len + sizeof(struct udphdr) + IPPROTO_UDP));
 923                 m->m_pkthdr.csum_flags = CSUM_UDP;
 924                 m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
 925         } else
 926                 ui->ui_sum = 0;
 927         ((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len;
 928         ((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl;    /* XXX */
 929         ((struct ip *)ui)->ip_tos = inp->inp_ip_tos;    /* XXX */
 930         udpstat.udps_opackets++;
 931
 932         if (unlock_udbinfo)
 933                 INP_INFO_WUNLOCK(&udbinfo);
 934         error = ip_output(m, inp->inp_options, NULL, ipflags,
 935             inp->inp_moptions, inp);
 936         INP_UNLOCK(inp);
 937         return (error);
 938
 939 release:
 940         INP_UNLOCK(inp);
 941         if (unlock_udbinfo)
 942                 INP_INFO_WUNLOCK(&udbinfo);
 943         m_freem(m);
 944         return (error);
 945 }
 946
 947 u_long  udp_sendspace = 9216;           /* really max datagram size */
 948                                         /* 40 1K datagrams */
 949 SYSCTL_ULONG(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW,
 950     &udp_sendspace, 0, "Maximum outgoing UDP datagram size");
 951
 952 u_long  udp_recvspace = 40 * (1024 +
 953 #ifdef INET6
 954                                       sizeof(struct sockaddr_in6)
 955 #else
 956                                       sizeof(struct sockaddr_in)
 957 #endif
 958                                       );
 959 SYSCTL_ULONG(_net_inet_udp, UDPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
 960     &udp_recvspace, 0, "Maximum space for incoming UDP datagrams");
 961
 962 static void
 963 udp_abort(struct socket *so)
 964 {
 965         struct inpcb *inp;
 966
 967         inp = sotoinpcb(so);
 968         KASSERT(inp != NULL, ("udp_abort: inp == NULL"));
 969         INP_INFO_WLOCK(&udbinfo);
 970         INP_LOCK(inp);
 971         if (inp->inp_faddr.s_addr != INADDR_ANY) {
 972                 in_pcbdisconnect(inp);
 973                 inp->inp_laddr.s_addr = INADDR_ANY;
 974                 soisdisconnected(so);
 975         }
 976         INP_UNLOCK(inp);
 977         INP_INFO_WUNLOCK(&udbinfo);
 978 }
 979
 980 static int
 981 udp_attach(struct socket *so, int proto, struct thread *td)
 982 {
 983         struct inpcb *inp;
 984         int error;
 985
 986         inp = sotoinpcb(so);
 987         KASSERT(inp == NULL, ("udp_attach: inp != NULL"));
 988         error = soreserve(so, udp_sendspace, udp_recvspace);
 989         if (error)
 990                 return (error);
 991         INP_INFO_WLOCK(&udbinfo);
 992         error = in_pcballoc(so, &udbinfo);
 993         if (error) {
 994                 INP_INFO_WUNLOCK(&udbinfo);
 995                 return (error);
 996         }
 997
 998         inp = (struct inpcb *)so->so_pcb;
 999         INP_INFO_WUNLOCK(&udbinfo);
1000         inp->inp_vflag |= INP_IPV4;
1001         inp->inp_ip_ttl = ip_defttl;
1002         INP_UNLOCK(inp);
1003         return (0);
1004 }
1005
1006 static int
1007 udp_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
1008 {
1009         struct inpcb *inp;
1010         int error;
1011
1012         inp = sotoinpcb(so);
1013         KASSERT(inp != NULL, ("udp_bind: inp == NULL"));
1014         INP_INFO_WLOCK(&udbinfo);
1015         INP_LOCK(inp);
1016         error = in_pcbbind(inp, nam, td->td_ucred);
1017         INP_UNLOCK(inp);
1018         INP_INFO_WUNLOCK(&udbinfo);
1019         return (error);
1020 }
1021
1022 static void
1023 udp_close(struct socket *so)
1024 {
1025         struct inpcb *inp;
1026
1027         inp = sotoinpcb(so);
1028         KASSERT(inp != NULL, ("udp_close: inp == NULL"));
1029         INP_INFO_WLOCK(&udbinfo);
1030         INP_LOCK(inp);
1031         if (inp->inp_faddr.s_addr != INADDR_ANY) {
1032                 in_pcbdisconnect(inp);
1033                 inp->inp_laddr.s_addr = INADDR_ANY;
1034                 soisdisconnected(so);
1035         }
1036         INP_UNLOCK(inp);
1037         INP_INFO_WUNLOCK(&udbinfo);
1038 }
1039
1040 static int
1041 udp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1042 {
1043         struct inpcb *inp;
1044         int error;
1045         struct sockaddr_in *sin;
1046
1047         inp = sotoinpcb(so);
1048         KASSERT(inp != NULL, ("udp_connect: inp == NULL"));
1049         INP_INFO_WLOCK(&udbinfo);
1050         INP_LOCK(inp);
1051         if (inp->inp_faddr.s_addr != INADDR_ANY) {
1052                 INP_UNLOCK(inp);
1053                 INP_INFO_WUNLOCK(&udbinfo);
1054                 return (EISCONN);
1055         }
1056         sin = (struct sockaddr_in *)nam;
1057         if (jailed(td->td_ucred))
1058                 prison_remote_ip(td->td_ucred, 0, &sin->sin_addr.s_addr);
1059         error = in_pcbconnect(inp, nam, td->td_ucred);
1060         if (error == 0)
1061                 soisconnected(so);
1062         INP_UNLOCK(inp);
1063         INP_INFO_WUNLOCK(&udbinfo);
1064         return (error);
1065 }
1066
1067 static void
1068 udp_detach(struct socket *so)
1069 {
1070         struct inpcb *inp;
1071
1072         inp = sotoinpcb(so);
1073         KASSERT(inp != NULL, ("udp_detach: inp == NULL"));
1074         KASSERT(inp->inp_faddr.s_addr == INADDR_ANY,
1075             ("udp_detach: not disconnected"));
1076         INP_INFO_WLOCK(&udbinfo);
1077         INP_LOCK(inp);
1078         in_pcbdetach(inp);
1079         in_pcbfree(inp);
1080         INP_INFO_WUNLOCK(&udbinfo);
1081 }
1082
1083 static int
1084 udp_disconnect(struct socket *so)
1085 {
1086         struct inpcb *inp;
1087
1088         inp = sotoinpcb(so);
1089         KASSERT(inp != NULL, ("udp_disconnect: inp == NULL"));
1090         INP_INFO_WLOCK(&udbinfo);
1091         INP_LOCK(inp);
1092         if (inp->inp_faddr.s_addr == INADDR_ANY) {
1093                 INP_INFO_WUNLOCK(&udbinfo);
1094                 INP_UNLOCK(inp);
1095                 return (ENOTCONN);
1096         }
1097
1098         in_pcbdisconnect(inp);
1099         inp->inp_laddr.s_addr = INADDR_ANY;
1100         SOCK_LOCK(so);
1101         so->so_state &= ~SS_ISCONNECTED;                /* XXX */
1102         SOCK_UNLOCK(so);
1103         INP_UNLOCK(inp);
1104         INP_INFO_WUNLOCK(&udbinfo);
1105         return (0);
1106 }
1107
1108 static int
1109 udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
1110     struct mbuf *control, struct thread *td)
1111 {
1112         struct inpcb *inp;
1113
1114         inp = sotoinpcb(so);
1115         KASSERT(inp != NULL, ("udp_send: inp == NULL"));
1116         return (udp_output(inp, m, addr, control, td));
1117 }
1118
1119 int
1120 udp_shutdown(struct socket *so)
1121 {
1122         struct inpcb *inp;
1123
1124         inp = sotoinpcb(so);
1125         KASSERT(inp != NULL, ("udp_shutdown: inp == NULL"));
1126         INP_LOCK(inp);
1127         socantsendmore(so);
1128         INP_UNLOCK(inp);
1129         return (0);
1130 }
1131
1132 /*
1133  * This is the wrapper function for in_setsockaddr.  We just pass down the
1134  * pcbinfo for in_setsockaddr() to lock.  We don't want to do the locking
1135  * here because in_setsockaddr() will call malloc and might block.
1136  */
1137 static int
1138 udp_sockaddr(struct socket *so, struct sockaddr **nam)
1139 {
1140
1141         return (in_setsockaddr(so, nam, &udbinfo));
1142 }
1143
1144 /*
1145  * This is the wrapper function for in_setpeeraddr().  We just pass down the
1146  * pcbinfo for in_setpeeraddr() to lock.
1147  */
1148 static int
1149 udp_peeraddr(struct socket *so, struct sockaddr **nam)
1150 {
1151
1152         return (in_setpeeraddr(so, nam, &udbinfo));
1153 }
1154
1155 struct pr_usrreqs udp_usrreqs = {
1156         .pru_abort =            udp_abort,
1157         .pru_attach =           udp_attach,
1158         .pru_bind =             udp_bind,
1159         .pru_connect =          udp_connect,
1160         .pru_control =          in_control,
1161         .pru_detach =           udp_detach,
1162         .pru_disconnect =       udp_disconnect,
1163         .pru_peeraddr =         udp_peeraddr,
1164         .pru_send =             udp_send,
1165         .pru_sosend =           sosend_dgram,
1166         .pru_shutdown =         udp_shutdown,
1167         .pru_sockaddr =         udp_sockaddr,
1168         .pru_sosetlabel =       in_pcbsosetlabel,
1169         .pru_close =            udp_close,
1170 };