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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)udp_usrreq.c 8.4 (Berkeley) 1/21/94 30 * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp 31 */ 32 33 /* 34 * Changes and additions relating to SLiRP 35 * Copyright (c) 1995 Danny Gasparovski. 36 * 37 * Please read the file COPYRIGHT for the 38 * terms and conditions of the copyright. 39 */ 40 41 #include <slirp.h> 42 #include "ip_icmp.h" 43 44 #ifdef LOG_ENABLED 45 struct udpstat udpstat; 46 #endif 47 48 struct socket udb; 49 50 static u_int8_t udp_tos(struct socket *so); 51 static void udp_emu(struct socket *so, struct mbuf *m); 52 53 /* 54 * UDP protocol implementation. 55 * Per RFC 768, August, 1980. 56 */ 57 #ifndef COMPAT_42 58 #define UDPCKSUM 1 59 #else 60 #define UDPCKSUM 0 /* XXX */ 61 #endif 62 63 struct socket *udp_last_so = &udb; 64 65 void 66 udp_init(void) 67 { 68 udb.so_next = udb.so_prev = &udb; 69 } 70 /* m->m_data points at ip packet header 71 * m->m_len length ip packet 72 * ip->ip_len length data (IPDU) 73 */ 74 void 75 udp_input(register struct mbuf *m, int iphlen) 76 { 77 register struct ip *ip; 78 register struct udphdr *uh; 79 /* struct mbuf *opts = 0;*/ 80 int len; 81 struct ip save_ip; 82 struct socket *so; 83 84 DEBUG_CALL("udp_input"); 85 DEBUG_ARG("m = %lx", (long)m); 86 DEBUG_ARG("iphlen = %d", iphlen); 87 88 STAT(udpstat.udps_ipackets++); 89 90 /* 91 * Strip IP options, if any; should skip this, 92 * make available to user, and use on returned packets, 93 * but we don't yet have a way to check the checksum 94 * with options still present. 95 */ 96 if(iphlen > sizeof(struct ip)) { 97 ip_stripoptions(m, (struct mbuf *)0); 98 iphlen = sizeof(struct ip); 99 } 100 101 /* 102 * Get IP and UDP header together in first mbuf. 103 */ 104 ip = mtod(m, struct ip *); 105 uh = (struct udphdr *)((caddr_t)ip + iphlen); 106 107 /* 108 * Make mbuf data length reflect UDP length. 109 * If not enough data to reflect UDP length, drop. 110 */ 111 len = ntohs((u_int16_t)uh->uh_ulen); 112 113 if (ip->ip_len != len) { 114 if (len > ip->ip_len) { 115 STAT(udpstat.udps_badlen++); 116 goto bad; 117 } 118 m_adj(m, len - ip->ip_len); 119 ip->ip_len = len; 120 } 121 122 /* 123 * Save a copy of the IP header in case we want restore it 124 * for sending an ICMP error message in response. 125 */ 126 save_ip = *ip; 127 save_ip.ip_len+= iphlen; /* tcp_input subtracts this */ 128 129 /* 130 * Checksum extended UDP header and data. 131 */ 132 if (UDPCKSUM && uh->uh_sum) { 133 memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr)); 134 ((struct ipovly *)ip)->ih_x1 = 0; 135 ((struct ipovly *)ip)->ih_len = uh->uh_ulen; 136 /* keep uh_sum for ICMP reply 137 * uh->uh_sum = cksum(m, len + sizeof (struct ip)); 138 * if (uh->uh_sum) { 139 */ 140 if(cksum(m, len + sizeof(struct ip))) { 141 STAT(udpstat.udps_badsum++); 142 goto bad; 143 } 144 } 145 146 /* 147 * handle DHCP/BOOTP 148 */ 149 if (ntohs(uh->uh_dport) == BOOTP_SERVER) { 150 bootp_input(m); 151 goto bad; 152 } 153 154 if (slirp_restrict) 155 goto bad; 156 157 /* 158 * handle TFTP 159 */ 160 if (ntohs(uh->uh_dport) == TFTP_SERVER) { 161 tftp_input(m); 162 goto bad; 163 } 164 165 /* 166 * Locate pcb for datagram. 167 */ 168 so = udp_last_so; 169 if (so->so_lport != uh->uh_sport || 170 so->so_laddr.s_addr != ip->ip_src.s_addr) { 171 struct socket *tmp; 172 173 for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) { 174 if (tmp->so_lport == uh->uh_sport && 175 tmp->so_laddr.s_addr == ip->ip_src.s_addr) { 176 tmp->so_faddr.s_addr = ip->ip_dst.s_addr; 177 tmp->so_fport = uh->uh_dport; 178 so = tmp; 179 break; 180 } 181 } 182 if (tmp == &udb) { 183 so = NULL; 184 } else { 185 STAT(udpstat.udpps_pcbcachemiss++); 186 udp_last_so = so; 187 } 188 } 189 190 if (so == NULL) { 191 /* 192 * If there's no socket for this packet, 193 * create one 194 */ 195 if ((so = socreate()) == NULL) goto bad; 196 if(udp_attach(so) == -1) { 197 DEBUG_MISC((dfd," udp_attach errno = %d-%s\n", 198 errno,strerror(errno))); 199 sofree(so); 200 goto bad; 201 } 202 203 /* 204 * Setup fields 205 */ 206 /* udp_last_so = so; */ 207 so->so_laddr = ip->ip_src; 208 so->so_lport = uh->uh_sport; 209 210 if ((so->so_iptos = udp_tos(so)) == 0) 211 so->so_iptos = ip->ip_tos; 212 213 /* 214 * XXXXX Here, check if it's in udpexec_list, 215 * and if it is, do the fork_exec() etc. 216 */ 217 } 218 219 so->so_faddr = ip->ip_dst; /* XXX */ 220 so->so_fport = uh->uh_dport; /* XXX */ 221 222 iphlen += sizeof(struct udphdr); 223 m->m_len -= iphlen; 224 m->m_data += iphlen; 225 226 /* 227 * Now we sendto() the packet. 228 */ 229 if (so->so_emu) 230 udp_emu(so, m); 231 232 if(sosendto(so,m) == -1) { 233 m->m_len += iphlen; 234 m->m_data -= iphlen; 235 *ip=save_ip; 236 DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno))); 237 icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno)); 238 } 239 240 m_free(so->so_m); /* used for ICMP if error on sorecvfrom */ 241 242 /* restore the orig mbuf packet */ 243 m->m_len += iphlen; 244 m->m_data -= iphlen; 245 *ip=save_ip; 246 so->so_m=m; /* ICMP backup */ 247 248 return; 249 bad: 250 m_freem(m); 251 /* if (opts) m_freem(opts); */ 252 return; 253 } 254 255 int udp_output2(struct socket *so, struct mbuf *m, 256 struct sockaddr_in *saddr, struct sockaddr_in *daddr, 257 int iptos) 258 { 259 register struct udpiphdr *ui; 260 int error = 0; 261 262 DEBUG_CALL("udp_output"); 263 DEBUG_ARG("so = %lx", (long)so); 264 DEBUG_ARG("m = %lx", (long)m); 265 DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr); 266 DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr); 267 268 /* 269 * Adjust for header 270 */ 271 m->m_data -= sizeof(struct udpiphdr); 272 m->m_len += sizeof(struct udpiphdr); 273 274 /* 275 * Fill in mbuf with extended UDP header 276 * and addresses and length put into network format. 277 */ 278 ui = mtod(m, struct udpiphdr *); 279 memset(&ui->ui_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr)); 280 ui->ui_x1 = 0; 281 ui->ui_pr = IPPROTO_UDP; 282 ui->ui_len = htons(m->m_len - sizeof(struct ip)); /* + sizeof (struct udphdr)); */ 283 /* XXXXX Check for from-one-location sockets, or from-any-location sockets */ 284 ui->ui_src = saddr->sin_addr; 285 ui->ui_dst = daddr->sin_addr; 286 ui->ui_sport = saddr->sin_port; 287 ui->ui_dport = daddr->sin_port; 288 ui->ui_ulen = ui->ui_len; 289 290 /* 291 * Stuff checksum and output datagram. 292 */ 293 ui->ui_sum = 0; 294 if (UDPCKSUM) { 295 if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ m->m_len)) == 0) 296 ui->ui_sum = 0xffff; 297 } 298 ((struct ip *)ui)->ip_len = m->m_len; 299 300 ((struct ip *)ui)->ip_ttl = IPDEFTTL; 301 ((struct ip *)ui)->ip_tos = iptos; 302 303 STAT(udpstat.udps_opackets++); 304 305 error = ip_output(so, m); 306 307 return (error); 308 } 309 310 int udp_output(struct socket *so, struct mbuf *m, 311 struct sockaddr_in *addr) 312 313 { 314 struct sockaddr_in saddr, daddr; 315 316 saddr = *addr; 317 if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) { 318 if ((so->so_faddr.s_addr & htonl(0x000000ff)) == htonl(0xff)) 319 saddr.sin_addr.s_addr = alias_addr.s_addr; 320 else if (addr->sin_addr.s_addr == loopback_addr.s_addr || 321 (ntohl(so->so_faddr.s_addr) & 0xff) != CTL_ALIAS) 322 saddr.sin_addr.s_addr = so->so_faddr.s_addr; 323 } 324 daddr.sin_addr = so->so_laddr; 325 daddr.sin_port = so->so_lport; 326 327 return udp_output2(so, m, &saddr, &daddr, so->so_iptos); 328 } 329 330 int 331 udp_attach(struct socket *so) 332 { 333 struct sockaddr_in addr; 334 335 if((so->s = socket(AF_INET,SOCK_DGRAM,0)) != -1) { 336 /* 337 * Here, we bind() the socket. Although not really needed 338 * (sendto() on an unbound socket will bind it), it's done 339 * here so that emulation of ytalk etc. don't have to do it 340 */ 341 addr.sin_family = AF_INET; 342 addr.sin_port = 0; 343 addr.sin_addr.s_addr = INADDR_ANY; 344 if(bind(so->s, (struct sockaddr *)&addr, sizeof(addr))<0) { 345 int lasterrno=errno; 346 closesocket(so->s); 347 so->s=-1; 348 #ifdef _WIN32 349 WSASetLastError(lasterrno); 350 #else 351 errno=lasterrno; 352 #endif 353 } else { 354 /* success, insert in queue */ 355 so->so_expire = curtime + SO_EXPIRE; 356 insque(so,&udb); 357 } 358 } 359 return(so->s); 360 } 361 362 void 363 udp_detach(struct socket *so) 364 { 365 closesocket(so->s); 366 /* if (so->so_m) m_free(so->so_m); done by sofree */ 367 368 sofree(so); 369 } 370 371 static const struct tos_t udptos[] = { 372 {0, 53, IPTOS_LOWDELAY, 0}, /* DNS */ 373 {517, 517, IPTOS_LOWDELAY, EMU_TALK}, /* talk */ 374 {518, 518, IPTOS_LOWDELAY, EMU_NTALK}, /* ntalk */ 375 {0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME}, /* Cu-Seeme */ 376 {0, 0, 0, 0} 377 }; 378 379 static u_int8_t 380 udp_tos(struct socket *so) 381 { 382 int i = 0; 383 384 while(udptos[i].tos) { 385 if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) || 386 (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) { 387 so->so_emu = udptos[i].emu; 388 return udptos[i].tos; 389 } 390 i++; 391 } 392 393 return 0; 394 } 395 396 #ifdef EMULATE_TALK 397 #include "talkd.h" 398 #endif 399 400 /* 401 * Here, talk/ytalk/ntalk requests must be emulated 402 */ 403 static void 404 udp_emu(struct socket *so, struct mbuf *m) 405 { 406 struct sockaddr_in addr; 407 socklen_t addrlen = sizeof(addr); 408 #ifdef EMULATE_TALK 409 CTL_MSG_OLD *omsg; 410 CTL_MSG *nmsg; 411 char buff[sizeof(CTL_MSG)]; 412 u_char type; 413 414 struct talk_request { 415 struct talk_request *next; 416 struct socket *udp_so; 417 struct socket *tcp_so; 418 } *req; 419 420 static struct talk_request *req_tbl = 0; 421 422 #endif 423 424 struct cu_header { 425 uint16_t d_family; // destination family 426 uint16_t d_port; // destination port 427 uint32_t d_addr; // destination address 428 uint16_t s_family; // source family 429 uint16_t s_port; // source port 430 uint32_t so_addr; // source address 431 uint32_t seqn; // sequence number 432 uint16_t message; // message 433 uint16_t data_type; // data type 434 uint16_t pkt_len; // packet length 435 } *cu_head; 436 437 switch(so->so_emu) { 438 439 #ifdef EMULATE_TALK 440 case EMU_TALK: 441 case EMU_NTALK: 442 /* 443 * Talk emulation. We always change the ctl_addr to get 444 * some answers from the daemon. When an ANNOUNCE comes, 445 * we send LEAVE_INVITE to the local daemons. Also when a 446 * DELETE comes, we send copies to the local daemons. 447 */ 448 if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0) 449 return; 450 451 #define IS_OLD (so->so_emu == EMU_TALK) 452 453 #define COPY_MSG(dest, src) { dest->type = src->type; \ 454 dest->id_num = src->id_num; \ 455 dest->pid = src->pid; \ 456 dest->addr = src->addr; \ 457 dest->ctl_addr = src->ctl_addr; \ 458 memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \ 459 memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \ 460 memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); } 461 462 #define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field) 463 /* old_sockaddr to sockaddr_in */ 464 465 466 if (IS_OLD) { /* old talk */ 467 omsg = mtod(m, CTL_MSG_OLD*); 468 nmsg = (CTL_MSG *) buff; 469 type = omsg->type; 470 OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port; 471 OTOSIN(omsg, ctl_addr)->sin_addr = our_addr; 472 pstrcpy(omsg->l_name, NAME_SIZE_OLD, getlogin()); 473 } else { /* new talk */ 474 omsg = (CTL_MSG_OLD *) buff; 475 nmsg = mtod(m, CTL_MSG *); 476 type = nmsg->type; 477 OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port; 478 OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr; 479 pstrcpy(nmsg->l_name, NAME_SIZE_OLD, getlogin()); 480 } 481 482 if (type == LOOK_UP) 483 return; /* for LOOK_UP this is enough */ 484 485 if (IS_OLD) { /* make a copy of the message */ 486 COPY_MSG(nmsg, omsg); 487 nmsg->vers = 1; 488 nmsg->answer = 0; 489 } else 490 COPY_MSG(omsg, nmsg); 491 492 /* 493 * If if is an ANNOUNCE message, we go through the 494 * request table to see if a tcp port has already 495 * been redirected for this socket. If not, we solisten() 496 * a new socket and add this entry to the table. 497 * The port number of the tcp socket and our IP 498 * are put to the addr field of the message structures. 499 * Then a LEAVE_INVITE is sent to both local daemon 500 * ports, 517 and 518. This is why we have two copies 501 * of the message, one in old talk and one in new talk 502 * format. 503 */ 504 505 if (type == ANNOUNCE) { 506 int s; 507 u_short temp_port; 508 509 for(req = req_tbl; req; req = req->next) 510 if (so == req->udp_so) 511 break; /* found it */ 512 513 if (!req) { /* no entry for so, create new */ 514 req = (struct talk_request *) 515 malloc(sizeof(struct talk_request)); 516 req->udp_so = so; 517 req->tcp_so = solisten(0, 518 OTOSIN(omsg, addr)->sin_addr.s_addr, 519 OTOSIN(omsg, addr)->sin_port, 520 SS_FACCEPTONCE); 521 req->next = req_tbl; 522 req_tbl = req; 523 } 524 525 /* replace port number in addr field */ 526 addrlen = sizeof(addr); 527 getsockname(req->tcp_so->s, 528 (struct sockaddr *) &addr, 529 &addrlen); 530 OTOSIN(omsg, addr)->sin_port = addr.sin_port; 531 OTOSIN(omsg, addr)->sin_addr = our_addr; 532 OTOSIN(nmsg, addr)->sin_port = addr.sin_port; 533 OTOSIN(nmsg, addr)->sin_addr = our_addr; 534 535 /* send LEAVE_INVITEs */ 536 temp_port = OTOSIN(omsg, ctl_addr)->sin_port; 537 OTOSIN(omsg, ctl_addr)->sin_port = 0; 538 OTOSIN(nmsg, ctl_addr)->sin_port = 0; 539 omsg->type = nmsg->type = LEAVE_INVITE; 540 541 s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP); 542 addr.sin_addr = our_addr; 543 addr.sin_family = AF_INET; 544 addr.sin_port = htons(517); 545 sendto(s, (char *)omsg, sizeof(*omsg), 0, 546 (struct sockaddr *)&addr, sizeof(addr)); 547 addr.sin_port = htons(518); 548 sendto(s, (char *)nmsg, sizeof(*nmsg), 0, 549 (struct sockaddr *) &addr, sizeof(addr)); 550 closesocket(s) ; 551 552 omsg->type = nmsg->type = ANNOUNCE; 553 OTOSIN(omsg, ctl_addr)->sin_port = temp_port; 554 OTOSIN(nmsg, ctl_addr)->sin_port = temp_port; 555 } 556 557 /* 558 * If it is a DELETE message, we send a copy to the 559 * local daemons. Then we delete the entry corresponding 560 * to our socket from the request table. 561 */ 562 563 if (type == DELETE) { 564 struct talk_request *temp_req, *req_next; 565 int s; 566 u_short temp_port; 567 568 temp_port = OTOSIN(omsg, ctl_addr)->sin_port; 569 OTOSIN(omsg, ctl_addr)->sin_port = 0; 570 OTOSIN(nmsg, ctl_addr)->sin_port = 0; 571 572 s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP); 573 addr.sin_addr = our_addr; 574 addr.sin_family = AF_INET; 575 addr.sin_port = htons(517); 576 sendto(s, (char *)omsg, sizeof(*omsg), 0, 577 (struct sockaddr *)&addr, sizeof(addr)); 578 addr.sin_port = htons(518); 579 sendto(s, (char *)nmsg, sizeof(*nmsg), 0, 580 (struct sockaddr *)&addr, sizeof(addr)); 581 closesocket(s); 582 583 OTOSIN(omsg, ctl_addr)->sin_port = temp_port; 584 OTOSIN(nmsg, ctl_addr)->sin_port = temp_port; 585 586 /* delete table entry */ 587 if (so == req_tbl->udp_so) { 588 temp_req = req_tbl; 589 req_tbl = req_tbl->next; 590 free(temp_req); 591 } else { 592 temp_req = req_tbl; 593 for(req = req_tbl->next; req; req = req_next) { 594 req_next = req->next; 595 if (so == req->udp_so) { 596 temp_req->next = req_next; 597 free(req); 598 break; 599 } else { 600 temp_req = req; 601 } 602 } 603 } 604 } 605 606 return; 607 #endif 608 609 case EMU_CUSEEME: 610 611 /* 612 * Cu-SeeMe emulation. 613 * Hopefully the packet is more that 16 bytes long. We don't 614 * do any other tests, just replace the address and port 615 * fields. 616 */ 617 if (m->m_len >= sizeof (*cu_head)) { 618 if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0) 619 return; 620 cu_head = mtod(m, struct cu_header *); 621 cu_head->s_port = addr.sin_port; 622 cu_head->so_addr = our_addr.s_addr; 623 } 624 625 return; 626 } 627 } 628 629 struct socket * 630 udp_listen(u_int port, u_int32_t laddr, u_int lport, int flags) 631 { 632 struct sockaddr_in addr; 633 struct socket *so; 634 socklen_t addrlen = sizeof(struct sockaddr_in), opt = 1; 635 636 if ((so = socreate()) == NULL) { 637 free(so); 638 return NULL; 639 } 640 so->s = socket(AF_INET,SOCK_DGRAM,0); 641 so->so_expire = curtime + SO_EXPIRE; 642 insque(so,&udb); 643 644 addr.sin_family = AF_INET; 645 addr.sin_addr.s_addr = INADDR_ANY; 646 addr.sin_port = port; 647 648 if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) { 649 udp_detach(so); 650 return NULL; 651 } 652 setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int)); 653 /* setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int)); */ 654 655 getsockname(so->s,(struct sockaddr *)&addr,&addrlen); 656 so->so_fport = addr.sin_port; 657 if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr) 658 so->so_faddr = alias_addr; 659 else 660 so->so_faddr = addr.sin_addr; 661 662 so->so_lport = lport; 663 so->so_laddr.s_addr = laddr; 664 if (flags != SS_FACCEPTONCE) 665 so->so_expire = 0; 666 667 so->so_state = SS_ISFCONNECTED; 668 669 return so; 670 } 671
