vde/slirpvde/udp.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1988, 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)udp_usrreq.c        8.4 (Berkeley) 1/21/94
  34  * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
  35  */
  36
  37 /*
  38  * Changes and additions relating to SLiRP
  39  * Copyright (c) 1995 Danny Gasparovski.
  40  *
  41  * Please read the file COPYRIGHT for the
  42  * terms and conditions of the copyright.
  43  */
  44
  45 #include <config.h>
  46 #include <slirp.h>
  47
  48 #include <ip_icmp.h>
  49
  50 #ifdef VDE
  51 extern int dhcpmgmt;
  52 #endif
  53
  54 struct udpstat udpstat;
  55
  56 struct socket udb;
  57
  58 /*
  59  * UDP protocol implementation.
  60  * Per RFC 768, August, 1980.
  61  */
  62 #ifndef COMPAT_42
  63 int     udpcksum = 1;
  64 #else
  65 int     udpcksum = 0;           /* XXX */
  66 #endif
  67
  68 struct  socket *udp_last_so = &udb;
  69
  70 void
  71 udp_init()
  72 {
  73         udb.so_next = udb.so_prev = &udb;
  74 }
  75 /* m->m_data  points at ip packet header
  76  * m->m_len   length ip packet
  77  * ip->ip_len length data (IPDU)
  78  */
  79 void
  80 udp_input(register struct mbuf *m, int iphlen)
  81 {
  82         register struct ip *ip;
  83         register struct udphdr *uh;
  84 /*      struct mbuf *opts = 0;*/
  85         int len;
  86         struct ip save_ip;
  87         struct socket *so;
  88
  89         DEBUG_CALL("udp_input");
  90         DEBUG_ARG("m = %lx", (long)m);
  91         DEBUG_ARG("iphlen = %d", iphlen);
  92
  93         udpstat.udps_ipackets++;
  94
  95         /*
  96          * Strip IP options, if any; should skip this,
  97          * make available to user, and use on returned packets,
  98          * but we don't yet have a way to check the checksum
  99          * with options still present.
 100          */
 101         if(iphlen > sizeof(struct ip)) {
 102                 ip_stripoptions(m, (struct mbuf *)0);
 103                 iphlen = sizeof(struct ip);
 104         }
 105
 106         /*
 107          * Get IP and UDP header together in first mbuf.
 108          */
 109         ip = mtod(m, struct ip *);
 110         uh = (struct udphdr *)((caddr_t)ip + iphlen);
 111
 112         /*
 113          * Make mbuf data length reflect UDP length.
 114          * If not enough data to reflect UDP length, drop.
 115          */
 116         len = ntohs((u_int16_t)uh->uh_ulen);
 117
 118         if (ip->ip_len != len) {
 119                 if (len > ip->ip_len) {
 120                         udpstat.udps_badlen++;
 121                         goto bad;
 122                 }
 123                 m_adj(m, len - ip->ip_len);
 124                 ip->ip_len = len;
 125         }
 126
 127         /*
 128          * Save a copy of the IP header in case we want restore it
 129          * for sending an ICMP error message in response.
 130          */
 131         save_ip = *ip;
 132         save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */
 133
 134         /*
 135          * Checksum extended UDP header and data.
 136          */
 137         if (udpcksum && uh->uh_sum) {
 138           ((struct ipovly *)ip)->ih_next = 0;
 139           ((struct ipovly *)ip)->ih_prev = 0;
 140           ((struct ipovly *)ip)->ih_x1 = 0;
 141           ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
 142           /* keep uh_sum for ICMP reply
 143            * uh->uh_sum = cksum(m, len + sizeof (struct ip));
 144            * if (uh->uh_sum) {
 145            */
 146           if(cksum(m, len + sizeof(struct ip))) {
 147             udpstat.udps_badsum++;
 148             goto bad;
 149           }
 150         }
 151
 152         /*
 153          *  handle DHCP/BOOTP
 154          */
 155 #ifdef VDE
 156         if (ntohs(uh->uh_dport) == BOOTP_SERVER && dhcpmgmt) {
 157 #else
 158         if (ntohs(uh->uh_dport) == BOOTP_SERVER) {
 159 #endif
 160             bootp_input(m);
 161             goto bad;
 162         }
 163
 164         /*
 165          * Locate pcb for datagram.
 166          */
 167         so = udp_last_so;
 168         if (so->so_lport != uh->uh_sport ||
 169             so->so_laddr.s_addr != ip->ip_src.s_addr) {
 170                 struct socket *tmp;
 171
 172                 for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) {
 173                         if (tmp->so_lport == uh->uh_sport &&
 174                             tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
 175                                 tmp->so_faddr.s_addr = ip->ip_dst.s_addr;
 176                                 tmp->so_fport = uh->uh_dport;
 177                                 so = tmp;
 178                                 break;
 179                         }
 180                 }
 181                 if (tmp == &udb) {
 182                   so = NULL;
 183                 } else {
 184                   udpstat.udpps_pcbcachemiss++;
 185                   udp_last_so = so;
 186                 }
 187         }
 188
 189         if (so == NULL) {
 190           /*
 191            * If there's no socket for this packet,
 192            * create one
 193            */
 194           if ((so = socreate()) == NULL) goto bad;
 195           if(udp_attach(so) == -1) {
 196             DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
 197                         errno,strerror(errno)));
 198             sofree(so);
 199             goto bad;
 200           }
 201
 202           /*
 203            * Setup fields
 204            */
 205           /* udp_last_so = so; */
 206           so->so_laddr = ip->ip_src;
 207           so->so_lport = uh->uh_sport;
 208           so->so_faddr = ip->ip_dst; /* XXX */
 209           so->so_fport = uh->uh_dport; /* XXX */
 210
 211           if ((so->so_iptos = udp_tos(so)) == 0)
 212             so->so_iptos = ip->ip_tos;
 213
 214           /*
 215            * XXXXX Here, check if it's in udpexec_list,
 216            * and if it is, do the fork_exec() etc.
 217            */
 218         }
 219
 220         iphlen += sizeof(struct udphdr);
 221         m->m_len -= iphlen;
 222         m->m_data += iphlen;
 223
 224         /*
 225          * Now we sendto() the packet.
 226          */
 227         if (so->so_emu)
 228            udp_emu(so, m);
 229
 230         if(sosendto(so,m) == -1) {
 231           m->m_len += iphlen;
 232           m->m_data -= iphlen;
 233           *ip=save_ip;
 234           DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
 235           icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
 236         }
 237
 238         m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
 239
 240         /* restore the orig mbuf packet */
 241         m->m_len += iphlen;
 242         m->m_data -= iphlen;
 243         *ip=save_ip;
 244         so->so_m=m;         /* ICMP backup */
 245
 246         return;
 247 bad:
 248         m_freem(m);
 249         /* if (opts) m_freem(opts); */
 250         return;
 251 }
 252
 253 int udp_output2(struct socket *so, struct mbuf *m,
 254                 struct sockaddr_in *saddr, struct sockaddr_in *daddr,
 255                 int iptos)
 256 {
 257         register struct udpiphdr *ui;
 258         int error = 0;
 259
 260         DEBUG_CALL("udp_output");
 261         DEBUG_ARG("so = %lx", (long)so);
 262         DEBUG_ARG("m = %lx", (long)m);
 263         DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
 264         DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
 265
 266         /*
 267          * Adjust for header
 268          */
 269         m->m_data -= sizeof(struct udpiphdr);
 270         m->m_len += sizeof(struct udpiphdr);
 271
 272         /*
 273          * Fill in mbuf with extended UDP header
 274          * and addresses and length put into network format.
 275          */
 276         ui = mtod(m, struct udpiphdr *);
 277         ui->ui_next = ui->ui_prev = 0;
 278         ui->ui_x1 = 0;
 279         ui->ui_pr = IPPROTO_UDP;
 280         ui->ui_len = htons(m->m_len - sizeof(struct ip)); /* + sizeof (struct udphdr)); */
 281         /* XXXXX Check for from-one-location sockets, or from-any-location sockets */
 282         ui->ui_src = saddr->sin_addr;
 283         ui->ui_dst = daddr->sin_addr;
 284         ui->ui_sport = saddr->sin_port;
 285         ui->ui_dport = daddr->sin_port;
 286         ui->ui_ulen = ui->ui_len;
 287
 288         /*
 289          * Stuff checksum and output datagram.
 290          */
 291         ui->ui_sum = 0;
 292         if (udpcksum) {
 293             if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ m->m_len)) == 0)
 294                 ui->ui_sum = 0xffff;
 295         }
 296         ((struct ip *)ui)->ip_len = m->m_len;
 297
 298         ((struct ip *)ui)->ip_ttl = ip_defttl;
 299         ((struct ip *)ui)->ip_tos = iptos;
 300
 301         udpstat.udps_opackets++;
 302
 303         error = ip_output(so, m);
 304
 305         return (error);
 306 }
 307
 308 int udp_output(struct socket *so, struct mbuf *m,
 309                struct sockaddr_in *addr)
 310
 311 {
 312     struct sockaddr_in saddr, daddr;
 313
 314     saddr = *addr;
 315     if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr)
 316         saddr.sin_addr.s_addr = so->so_faddr.s_addr;
 317     daddr.sin_addr = so->so_laddr;
 318     daddr.sin_port = so->so_lport;
 319
 320     return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
 321 }
 322
 323 int
 324 udp_attach(so)
 325      struct socket *so;
 326 {
 327   struct sockaddr_in addr;
 328
 329   if((so->s = socket(AF_INET,SOCK_DGRAM,0)) != -1) {
 330     /*
 331      * Here, we bind() the socket.  Although not really needed
 332      * (sendto() on an unbound socket will bind it), it's done
 333      * here so that emulation of ytalk etc. don't have to do it
 334      */
 335     addr.sin_family = AF_INET;
 336     addr.sin_port = 0;
 337     addr.sin_addr.s_addr = INADDR_ANY;
 338     if(bind(so->s, (struct sockaddr *)&addr, sizeof(addr))<0) {
 339       int lasterrno=errno;
 340       close(so->s);
 341       so->s=-1;
 342       errno=lasterrno;
 343     } else {
 344       /* success, insert in queue */
 345       so->so_expire = curtime + SO_EXPIRE;
 346       insque(so,&udb);
 347     }
 348   }
 349   return(so->s);
 350 }
 351
 352 void
 353 udp_detach(so)
 354         struct socket *so;
 355 {
 356         close(so->s);
 357         /* if (so->so_m) m_free(so->so_m);    done by sofree */
 358
 359         sofree(so);
 360 }
 361
 362 struct tos_t udptos[] = {
 363         {0, 53, IPTOS_LOWDELAY, 0},                     /* DNS */
 364         {517, 517, IPTOS_LOWDELAY, EMU_TALK},   /* talk */
 365         {518, 518, IPTOS_LOWDELAY, EMU_NTALK},  /* ntalk */
 366         {0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME}, /* Cu-Seeme */
 367         {0, 0, 0, 0}
 368 };
 369
 370 u_int8_t
 371 udp_tos(so)
 372         struct socket *so;
 373 {
 374         int i = 0;
 375
 376         while(udptos[i].tos) {
 377                 if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
 378                     (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
 379                         so->so_emu = udptos[i].emu;
 380                         return udptos[i].tos;
 381                 }
 382                 i++;
 383         }
 384
 385         return 0;
 386 }
 387
 388 #ifdef EMULATE_TALK
 389 #include <talkd.h>
 390 #endif
 391
 392 /*
 393  * Here, talk/ytalk/ntalk requests must be emulated
 394  */
 395 void
 396 udp_emu(so, m)
 397         struct socket *so;
 398         struct mbuf *m;
 399 {
 400         struct sockaddr_in addr;
 401         int addrlen = sizeof(addr);
 402 #ifdef EMULATE_TALK
 403         CTL_MSG_OLD *omsg;
 404         CTL_MSG *nmsg;
 405         char buff[sizeof(CTL_MSG)];
 406         u_char type;
 407
 408 struct talk_request {
 409         struct talk_request *next;
 410         struct socket *udp_so;
 411         struct socket *tcp_so;
 412 } *req;
 413
 414         static struct talk_request *req_tbl = 0;
 415
 416 #endif
 417
 418 struct cu_header {
 419         char    dest[8];
 420         short   family;
 421         u_short port;
 422         u_long  addr;
 423 } *cu_head;
 424
 425         switch(so->so_emu) {
 426
 427 #ifdef EMULATE_TALK
 428          case EMU_TALK:
 429          case EMU_NTALK:
 430                 /*
 431                  * Talk emulation. We always change the ctl_addr to get
 432                  * some answers from the daemon. When an ANNOUNCE comes,
 433                  * we send LEAVE_INVITE to the local daemons. Also when a
 434                  * DELETE comes, we send copies to the local daemons.
 435                  */
 436                 if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
 437                         return;
 438
 439 #define IS_OLD  (so->so_emu == EMU_TALK)
 440
 441 #define COPY_MSG(dest, src) { dest->type = src->type; \
 442                               dest->id_num = src->id_num; \
 443                               dest->pid = src->pid; \
 444                               dest->addr = src->addr; \
 445                               dest->ctl_addr = src->ctl_addr; \
 446                               memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \
 447                               memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \
 448                               memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); }
 449
 450 #define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field)
 451 /* old_sockaddr to sockaddr_in */
 452
 453
 454                 if (IS_OLD) {           /* old talk */
 455                         omsg = mtod(m, CTL_MSG_OLD*);
 456                         nmsg = (CTL_MSG *) buff;
 457                         type = omsg->type;
 458                         OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port;
 459                         OTOSIN(omsg, ctl_addr)->sin_addr = our_addr;
 460                         strncpy(omsg->l_name, getlogin(), NAME_SIZE_OLD);
 461                 } else {                /* new talk */
 462                         omsg = (CTL_MSG_OLD *) buff;
 463                         nmsg = mtod(m, CTL_MSG *);
 464                         type = nmsg->type;
 465                         OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port;
 466                         OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr;
 467                         strncpy(nmsg->l_name, getlogin(), NAME_SIZE_OLD);
 468                 }
 469
 470                 if (type == LOOK_UP)
 471                         return;         /* for LOOK_UP this is enough */
 472
 473                 if (IS_OLD) {           /* make a copy of the message */
 474                         COPY_MSG(nmsg, omsg);
 475                         nmsg->vers = 1;
 476                         nmsg->answer = 0;
 477                 } else
 478                         COPY_MSG(omsg, nmsg);
 479
 480                 /*
 481                  * If if is an ANNOUNCE message, we go through the
 482                  * request table to see if a tcp port has already
 483                  * been redirected for this socket. If not, we solisten()
 484                  * a new socket and add this entry to the table.
 485                  * The port number of the tcp socket and our IP
 486                  * are put to the addr field of the message structures.
 487                  * Then a LEAVE_INVITE is sent to both local daemon
 488                  * ports, 517 and 518. This is why we have two copies
 489                  * of the message, one in old talk and one in new talk
 490                  * format.
 491                  */
 492
 493                 if (type == ANNOUNCE) {
 494                         int s;
 495                         u_short temp_port;
 496
 497                         for(req = req_tbl; req; req = req->next)
 498                                 if (so == req->udp_so)
 499                                         break;          /* found it */
 500
 501                         if (!req) {     /* no entry for so, create new */
 502                                 req = (struct talk_request *)
 503                                         malloc(sizeof(struct talk_request));
 504                                 req->udp_so = so;
 505                                 req->tcp_so = solisten(0,
 506                                         OTOSIN(omsg, addr)->sin_addr.s_addr,
 507                                         OTOSIN(omsg, addr)->sin_port,
 508                                         SS_FACCEPTONCE);
 509                                 req->next = req_tbl;
 510                                 req_tbl = req;
 511                         }
 512
 513                         /* replace port number in addr field */
 514                         addrlen = sizeof(addr);
 515                         getsockname(req->tcp_so->s,
 516                                         (struct sockaddr *) &addr,
 517                                         &addrlen);
 518                         OTOSIN(omsg, addr)->sin_port = addr.sin_port;
 519                         OTOSIN(omsg, addr)->sin_addr = our_addr;
 520                         OTOSIN(nmsg, addr)->sin_port = addr.sin_port;
 521                         OTOSIN(nmsg, addr)->sin_addr = our_addr;
 522
 523                         /* send LEAVE_INVITEs */
 524                         temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
 525                         OTOSIN(omsg, ctl_addr)->sin_port = 0;
 526                         OTOSIN(nmsg, ctl_addr)->sin_port = 0;
 527                         omsg->type = nmsg->type = LEAVE_INVITE;
 528
 529                         s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 530                         addr.sin_addr = our_addr;
 531                         addr.sin_family = AF_INET;
 532                         addr.sin_port = htons(517);
 533                         sendto(s, (char *)omsg, sizeof(*omsg), 0,
 534                                 (struct sockaddr *)&addr, sizeof(addr));
 535                         addr.sin_port = htons(518);
 536                         sendto(s, (char *)nmsg, sizeof(*nmsg), 0,
 537                                 (struct sockaddr *) &addr, sizeof(addr));
 538                         close(s) ;
 539
 540                         omsg->type = nmsg->type = ANNOUNCE;
 541                         OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
 542                         OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
 543                 }
 544
 545                 /*
 546                  * If it is a DELETE message, we send a copy to the
 547                  * local daemons. Then we delete the entry corresponding
 548                  * to our socket from the request table.
 549                  */
 550
 551                 if (type == DELETE) {
 552                         struct talk_request *temp_req, *req_next;
 553                         int s;
 554                         u_short temp_port;
 555
 556                         temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
 557                         OTOSIN(omsg, ctl_addr)->sin_port = 0;
 558                         OTOSIN(nmsg, ctl_addr)->sin_port = 0;
 559
 560                         s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 561                         addr.sin_addr = our_addr;
 562                         addr.sin_family = AF_INET;
 563                         addr.sin_port = htons(517);
 564                         sendto(s, (char *)omsg, sizeof(*omsg), 0,
 565                                 (struct sockaddr *)&addr, sizeof(addr));
 566                         addr.sin_port = htons(518);
 567                         sendto(s, (char *)nmsg, sizeof(*nmsg), 0,
 568                                 (struct sockaddr *)&addr, sizeof(addr));
 569                         close(s);
 570
 571                         OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
 572                         OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
 573
 574                         /* delete table entry */
 575                         if (so == req_tbl->udp_so) {
 576                                 temp_req = req_tbl;
 577                                 req_tbl = req_tbl->next;
 578                                 free(temp_req);
 579                         } else {
 580                                 temp_req = req_tbl;
 581                                 for(req = req_tbl->next; req; req = req_next) {
 582                                         req_next = req->next;
 583                                         if (so == req->udp_so) {
 584                                                 temp_req->next = req_next;
 585                                                 free(req);
 586                                                 break;
 587                                         } else {
 588                                                 temp_req = req;
 589                                         }
 590                                 }
 591                         }
 592                 }
 593
 594                 return;
 595 #endif
 596
 597         case EMU_CUSEEME:
 598
 599                 /*
 600                  * Cu-SeeMe emulation.
 601                  * Hopefully the packet is more that 16 bytes long. We don't
 602                  * do any other tests, just replace the address and port
 603                  * fields.
 604                  */
 605                 if (m->m_len >= sizeof (*cu_head)) {
 606                         if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
 607                                 return;
 608                         cu_head = mtod(m, struct cu_header *);
 609                         cu_head->port = addr.sin_port;
 610                         cu_head->addr = (u_long) our_addr.s_addr;
 611                 }
 612
 613                 return;
 614         }
 615 }
 616
 617 struct socket *
 618 udp_listen(port, laddr, lport, flags)
 619         u_int port;
 620         u_int32_t laddr;
 621         u_int lport;
 622         int flags;
 623 {
 624         struct sockaddr_in addr;
 625         struct socket *so;
 626         int addrlen = sizeof(struct sockaddr_in), opt = 1;
 627
 628         if ((so = socreate()) == NULL) {
 629                 free(so);
 630                 return NULL;
 631         }
 632         so->s = socket(AF_INET,SOCK_DGRAM,0);
 633         so->so_expire = curtime + SO_EXPIRE;
 634         insque(so,&udb);
 635
 636         addr.sin_family = AF_INET;
 637         addr.sin_addr.s_addr = INADDR_ANY;
 638         addr.sin_port = port;
 639
 640         if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
 641                 udp_detach(so);
 642                 return NULL;
 643         }
 644         setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
 645 /*      setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int)); */
 646
 647         getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
 648         so->so_fport = addr.sin_port;
 649         if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr)
 650            so->so_faddr = our_addr;
 651         else
 652            so->so_faddr = addr.sin_addr;
 653
 654         so->so_lport = lport;
 655         so->so_laddr.s_addr = laddr;
 656         if (flags != SS_FACCEPTONCE)
 657            so->so_expire = 0;
 658
 659         so->so_state = SS_ISFCONNECTED;
 660
 661         return so;
 662 }