1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)udp_usrreq.c 8.6 (Berkeley) 05/23/95 8 */ 9 10 #include <sys/param.h> 11 #include <sys/malloc.h> 12 #include <sys/mbuf.h> 13 #include <sys/protosw.h> 14 #include <sys/socket.h> 15 #include <sys/socketvar.h> 16 #include <sys/errno.h> 17 #include <sys/stat.h> 18 19 #include <net/if.h> 20 #include <net/route.h> 21 22 #include <netinet/in.h> 23 #include <netinet/in_systm.h> 24 #include <netinet/ip.h> 25 #include <netinet/in_pcb.h> 26 #include <netinet/ip_var.h> 27 #include <netinet/ip_icmp.h> 28 #include <netinet/udp.h> 29 #include <netinet/udp_var.h> 30 31 /* 32 * UDP protocol implementation. 33 * Per RFC 768, August, 1980. 34 */ 35 #ifndef COMPAT_42 36 int udpcksum = 1; 37 #else 38 int udpcksum = 0; /* XXX */ 39 #endif 40 41 struct sockaddr_in udp_in = { sizeof(udp_in), AF_INET }; 42 struct inpcb *udp_last_inpcb = &udb; 43 44 static void udp_detach __P((struct inpcb *)); 45 static void udp_notify __P((struct inpcb *, int)); 46 static struct mbuf *udp_saveopt __P((caddr_t, int, int)); 47 48 void 49 udp_init() 50 { 51 udb.inp_next = udb.inp_prev = &udb; 52 } 53 54 void 55 udp_input(m, iphlen) 56 register struct mbuf *m; 57 int iphlen; 58 { 59 register struct ip *ip; 60 register struct udphdr *uh; 61 register struct inpcb *inp; 62 struct mbuf *opts = 0; 63 int len; 64 struct ip save_ip; 65 66 udpstat.udps_ipackets++; 67 68 /* 69 * Strip IP options, if any; should skip this, 70 * make available to user, and use on returned packets, 71 * but we don't yet have a way to check the checksum 72 * with options still present. 73 */ 74 if (iphlen > sizeof (struct ip)) { 75 ip_stripoptions(m, (struct mbuf *)0); 76 iphlen = sizeof(struct ip); 77 } 78 79 /* 80 * Get IP and UDP header together in first mbuf. 81 */ 82 ip = mtod(m, struct ip *); 83 if (m->m_len < iphlen + sizeof(struct udphdr)) { 84 if ((m = m_pullup(m, iphlen + sizeof(struct udphdr))) == 0) { 85 udpstat.udps_hdrops++; 86 return; 87 } 88 ip = mtod(m, struct ip *); 89 } 90 uh = (struct udphdr *)((caddr_t)ip + iphlen); 91 92 /* 93 * Make mbuf data length reflect UDP length. 94 * If not enough data to reflect UDP length, drop. 95 */ 96 len = ntohs((u_short)uh->uh_ulen); 97 if (ip->ip_len != len) { 98 if (len > ip->ip_len) { 99 udpstat.udps_badlen++; 100 goto bad; 101 } 102 m_adj(m, len - ip->ip_len); 103 /* ip->ip_len = len; */ 104 } 105 /* 106 * Save a copy of the IP header in case we want restore it 107 * for sending an ICMP error message in response. 108 */ 109 save_ip = *ip; 110 111 /* 112 * Checksum extended UDP header and data. 113 */ 114 if (uh->uh_sum) { 115 ((struct ipovly *)ip)->ih_next = 0; 116 ((struct ipovly *)ip)->ih_prev = 0; 117 ((struct ipovly *)ip)->ih_x1 = 0; 118 ((struct ipovly *)ip)->ih_len = uh->uh_ulen; 119 if (uh->uh_sum = in_cksum(m, len + sizeof (struct ip))) { 120 udpstat.udps_badsum++; 121 m_freem(m); 122 return; 123 } 124 } 125 126 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 127 in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) { 128 struct socket *last; 129 /* 130 * Deliver a multicast or broadcast datagram to *all* sockets 131 * for which the local and remote addresses and ports match 132 * those of the incoming datagram. This allows more than 133 * one process to receive multi/broadcasts on the same port. 134 * (This really ought to be done for unicast datagrams as 135 * well, but that would cause problems with existing 136 * applications that open both address-specific sockets and 137 * a wildcard socket listening to the same port -- they would 138 * end up receiving duplicates of every unicast datagram. 139 * Those applications open the multiple sockets to overcome an 140 * inadequacy of the UDP socket interface, but for backwards 141 * compatibility we avoid the problem here rather than 142 * fixing the interface. Maybe 4.5BSD will remedy this?) 143 */ 144 145 /* 146 * Construct sockaddr format source address. 147 */ 148 udp_in.sin_port = uh->uh_sport; 149 udp_in.sin_addr = ip->ip_src; 150 m->m_len -= sizeof (struct udpiphdr); 151 m->m_data += sizeof (struct udpiphdr); 152 /* 153 * Locate pcb(s) for datagram. 154 * (Algorithm copied from raw_intr().) 155 */ 156 last = NULL; 157 for (inp = udb.inp_next; inp != &udb; inp = inp->inp_next) { 158 if (inp->inp_lport != uh->uh_dport) 159 continue; 160 if (inp->inp_laddr.s_addr != INADDR_ANY) { 161 if (inp->inp_laddr.s_addr != 162 ip->ip_dst.s_addr) 163 continue; 164 } 165 if (inp->inp_faddr.s_addr != INADDR_ANY) { 166 if (inp->inp_faddr.s_addr != 167 ip->ip_src.s_addr || 168 inp->inp_fport != uh->uh_sport) 169 continue; 170 } 171 172 if (last != NULL) { 173 struct mbuf *n; 174 175 if ((n = m_copy(m, 0, M_COPYALL)) != NULL) { 176 if (sbappendaddr(&last->so_rcv, 177 (struct sockaddr *)&udp_in, 178 n, (struct mbuf *)0) == 0) { 179 m_freem(n); 180 udpstat.udps_fullsock++; 181 } else 182 sorwakeup(last); 183 } 184 } 185 last = inp->inp_socket; 186 /* 187 * Don't look for additional matches if this one does 188 * not have either the SO_REUSEPORT or SO_REUSEADDR 189 * socket options set. This heuristic avoids searching 190 * through all pcbs in the common case of a non-shared 191 * port. It * assumes that an application will never 192 * clear these options after setting them. 193 */ 194 if ((last->so_options&(SO_REUSEPORT|SO_REUSEADDR) == 0)) 195 break; 196 } 197 198 if (last == NULL) { 199 /* 200 * No matching pcb found; discard datagram. 201 * (No need to send an ICMP Port Unreachable 202 * for a broadcast or multicast datgram.) 203 */ 204 udpstat.udps_noportbcast++; 205 goto bad; 206 } 207 if (sbappendaddr(&last->so_rcv, (struct sockaddr *)&udp_in, 208 m, (struct mbuf *)0) == 0) { 209 udpstat.udps_fullsock++; 210 goto bad; 211 } 212 sorwakeup(last); 213 return; 214 } 215 /* 216 * Locate pcb for datagram. 217 */ 218 inp = udp_last_inpcb; 219 if (inp->inp_lport != uh->uh_dport || 220 inp->inp_fport != uh->uh_sport || 221 inp->inp_faddr.s_addr != ip->ip_src.s_addr || 222 inp->inp_laddr.s_addr != ip->ip_dst.s_addr) { 223 inp = in_pcblookup(&udb, ip->ip_src, uh->uh_sport, 224 ip->ip_dst, uh->uh_dport, INPLOOKUP_WILDCARD); 225 if (inp) 226 udp_last_inpcb = inp; 227 udpstat.udpps_pcbcachemiss++; 228 } 229 if (inp == 0) { 230 udpstat.udps_noport++; 231 if (m->m_flags & (M_BCAST | M_MCAST)) { 232 udpstat.udps_noportbcast++; 233 goto bad; 234 } 235 *ip = save_ip; 236 ip->ip_len += iphlen; 237 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0); 238 return; 239 } 240 241 /* 242 * Construct sockaddr format source address. 243 * Stuff source address and datagram in user buffer. 244 */ 245 udp_in.sin_port = uh->uh_sport; 246 udp_in.sin_addr = ip->ip_src; 247 if (inp->inp_flags & INP_CONTROLOPTS) { 248 struct mbuf **mp = &opts; 249 250 if (inp->inp_flags & INP_RECVDSTADDR) { 251 *mp = udp_saveopt((caddr_t) &ip->ip_dst, 252 sizeof(struct in_addr), IP_RECVDSTADDR); 253 if (*mp) 254 mp = &(*mp)->m_next; 255 } 256 #ifdef notyet 257 /* options were tossed above */ 258 if (inp->inp_flags & INP_RECVOPTS) { 259 *mp = udp_saveopt((caddr_t) opts_deleted_above, 260 sizeof(struct in_addr), IP_RECVOPTS); 261 if (*mp) 262 mp = &(*mp)->m_next; 263 } 264 /* ip_srcroute doesn't do what we want here, need to fix */ 265 if (inp->inp_flags & INP_RECVRETOPTS) { 266 *mp = udp_saveopt((caddr_t) ip_srcroute(), 267 sizeof(struct in_addr), IP_RECVRETOPTS); 268 if (*mp) 269 mp = &(*mp)->m_next; 270 } 271 #endif 272 } 273 iphlen += sizeof(struct udphdr); 274 m->m_len -= iphlen; 275 m->m_pkthdr.len -= iphlen; 276 m->m_data += iphlen; 277 if (sbappendaddr(&inp->inp_socket->so_rcv, (struct sockaddr *)&udp_in, 278 m, opts) == 0) { 279 udpstat.udps_fullsock++; 280 goto bad; 281 } 282 sorwakeup(inp->inp_socket); 283 return; 284 bad: 285 m_freem(m); 286 if (opts) 287 m_freem(opts); 288 } 289 290 /* 291 * Create a "control" mbuf containing the specified data 292 * with the specified type for presentation with a datagram. 293 */ 294 struct mbuf * 295 udp_saveopt(p, size, type) 296 caddr_t p; 297 register int size; 298 int type; 299 { 300 register struct cmsghdr *cp; 301 struct mbuf *m; 302 303 if ((m = m_get(M_DONTWAIT, MT_CONTROL)) == NULL) 304 return ((struct mbuf *) NULL); 305 cp = (struct cmsghdr *) mtod(m, struct cmsghdr *); 306 bcopy(p, CMSG_DATA(cp), size); 307 size += sizeof(*cp); 308 m->m_len = size; 309 cp->cmsg_len = size; 310 cp->cmsg_level = IPPROTO_IP; 311 cp->cmsg_type = type; 312 return (m); 313 } 314 315 /* 316 * Notify a udp user of an asynchronous error; 317 * just wake up so that he can collect error status. 318 */ 319 static void 320 udp_notify(inp, errno) 321 register struct inpcb *inp; 322 int errno; 323 { 324 inp->inp_socket->so_error = errno; 325 sorwakeup(inp->inp_socket); 326 sowwakeup(inp->inp_socket); 327 } 328 329 void 330 udp_ctlinput(cmd, sa, ip) 331 int cmd; 332 struct sockaddr *sa; 333 register struct ip *ip; 334 { 335 register struct udphdr *uh; 336 extern struct in_addr zeroin_addr; 337 extern u_char inetctlerrmap[]; 338 339 if (!PRC_IS_REDIRECT(cmd) && 340 ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)) 341 return; 342 if (ip) { 343 uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2)); 344 in_pcbnotify(&udb, sa, uh->uh_dport, ip->ip_src, uh->uh_sport, 345 cmd, udp_notify); 346 } else 347 in_pcbnotify(&udb, sa, 0, zeroin_addr, 0, cmd, udp_notify); 348 } 349 350 int 351 udp_output(inp, m, addr, control) 352 register struct inpcb *inp; 353 register struct mbuf *m; 354 struct mbuf *addr, *control; 355 { 356 register struct udpiphdr *ui; 357 register int len = m->m_pkthdr.len; 358 struct in_addr laddr; 359 int s, error = 0; 360 361 if (control) 362 m_freem(control); /* XXX */ 363 364 if (addr) { 365 laddr = inp->inp_laddr; 366 if (inp->inp_faddr.s_addr != INADDR_ANY) { 367 error = EISCONN; 368 goto release; 369 } 370 /* 371 * Must block input while temporarily connected. 372 */ 373 s = splnet(); 374 error = in_pcbconnect(inp, addr); 375 if (error) { 376 splx(s); 377 goto release; 378 } 379 } else { 380 if (inp->inp_faddr.s_addr == INADDR_ANY) { 381 error = ENOTCONN; 382 goto release; 383 } 384 } 385 /* 386 * Calculate data length and get a mbuf 387 * for UDP and IP headers. 388 */ 389 M_PREPEND(m, sizeof(struct udpiphdr), M_DONTWAIT); 390 if (m == 0) { 391 error = ENOBUFS; 392 goto release; 393 } 394 395 /* 396 * Fill in mbuf with extended UDP header 397 * and addresses and length put into network format. 398 */ 399 ui = mtod(m, struct udpiphdr *); 400 ui->ui_next = ui->ui_prev = 0; 401 ui->ui_x1 = 0; 402 ui->ui_pr = IPPROTO_UDP; 403 ui->ui_len = htons((u_short)len + sizeof (struct udphdr)); 404 ui->ui_src = inp->inp_laddr; 405 ui->ui_dst = inp->inp_faddr; 406 ui->ui_sport = inp->inp_lport; 407 ui->ui_dport = inp->inp_fport; 408 ui->ui_ulen = ui->ui_len; 409 410 /* 411 * Stuff checksum and output datagram. 412 */ 413 ui->ui_sum = 0; 414 if (udpcksum) { 415 if ((ui->ui_sum = in_cksum(m, sizeof (struct udpiphdr) + len)) == 0) 416 ui->ui_sum = 0xffff; 417 } 418 ((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len; 419 ((struct ip *)ui)->ip_ttl = inp->inp_ip.ip_ttl; /* XXX */ 420 ((struct ip *)ui)->ip_tos = inp->inp_ip.ip_tos; /* XXX */ 421 udpstat.udps_opackets++; 422 error = ip_output(m, inp->inp_options, &inp->inp_route, 423 inp->inp_socket->so_options & (SO_DONTROUTE | SO_BROADCAST), 424 inp->inp_moptions); 425 426 if (addr) { 427 in_pcbdisconnect(inp); 428 inp->inp_laddr = laddr; 429 splx(s); 430 } 431 return (error); 432 433 release: 434 m_freem(m); 435 return (error); 436 } 437 438 u_long udp_sendspace = 9216; /* really max datagram size */ 439 u_long udp_recvspace = 40 * (1024 + sizeof(struct sockaddr_in)); 440 /* 40 1K datagrams */ 441 442 /*ARGSUSED*/ 443 int 444 udp_usrreq(so, req, m, addr, control) 445 struct socket *so; 446 int req; 447 struct mbuf *m, *addr, *control; 448 { 449 struct inpcb *inp = sotoinpcb(so); 450 int error = 0; 451 int s; 452 453 if (req == PRU_CONTROL) 454 return (in_control(so, (u_long)m, (caddr_t)addr, 455 (struct ifnet *)control)); 456 if (inp == NULL && req != PRU_ATTACH) { 457 error = EINVAL; 458 goto release; 459 } 460 /* 461 * Note: need to block udp_input while changing 462 * the udp pcb queue and/or pcb addresses. 463 */ 464 switch (req) { 465 466 case PRU_ATTACH: 467 if (inp != NULL) { 468 error = EINVAL; 469 break; 470 } 471 s = splnet(); 472 error = in_pcballoc(so, &udb); 473 splx(s); 474 if (error) 475 break; 476 error = soreserve(so, udp_sendspace, udp_recvspace); 477 if (error) 478 break; 479 ((struct inpcb *) so->so_pcb)->inp_ip.ip_ttl = ip_defttl; 480 break; 481 482 case PRU_DETACH: 483 udp_detach(inp); 484 break; 485 486 case PRU_BIND: 487 s = splnet(); 488 error = in_pcbbind(inp, addr); 489 splx(s); 490 break; 491 492 case PRU_LISTEN: 493 error = EOPNOTSUPP; 494 break; 495 496 case PRU_CONNECT: 497 if (inp->inp_faddr.s_addr != INADDR_ANY) { 498 error = EISCONN; 499 break; 500 } 501 s = splnet(); 502 error = in_pcbconnect(inp, addr); 503 splx(s); 504 if (error == 0) 505 soisconnected(so); 506 break; 507 508 case PRU_CONNECT2: 509 error = EOPNOTSUPP; 510 break; 511 512 case PRU_ACCEPT: 513 error = EOPNOTSUPP; 514 break; 515 516 case PRU_DISCONNECT: 517 if (inp->inp_faddr.s_addr == INADDR_ANY) { 518 error = ENOTCONN; 519 break; 520 } 521 s = splnet(); 522 in_pcbdisconnect(inp); 523 inp->inp_laddr.s_addr = INADDR_ANY; 524 splx(s); 525 so->so_state &= ~SS_ISCONNECTED; /* XXX */ 526 break; 527 528 case PRU_SHUTDOWN: 529 socantsendmore(so); 530 break; 531 532 case PRU_SEND: 533 return (udp_output(inp, m, addr, control)); 534 535 case PRU_ABORT: 536 soisdisconnected(so); 537 udp_detach(inp); 538 break; 539 540 case PRU_SOCKADDR: 541 in_setsockaddr(inp, addr); 542 break; 543 544 case PRU_PEERADDR: 545 in_setpeeraddr(inp, addr); 546 break; 547 548 case PRU_SENSE: 549 /* 550 * stat: don't bother with a blocksize. 551 */ 552 return (0); 553 554 case PRU_SENDOOB: 555 case PRU_FASTTIMO: 556 case PRU_SLOWTIMO: 557 case PRU_PROTORCV: 558 case PRU_PROTOSEND: 559 error = EOPNOTSUPP; 560 break; 561 562 case PRU_RCVD: 563 case PRU_RCVOOB: 564 return (EOPNOTSUPP); /* do not free mbuf's */ 565 566 default: 567 panic("udp_usrreq"); 568 } 569 570 release: 571 if (control) { 572 printf("udp control data unexpectedly retained\n"); 573 m_freem(control); 574 } 575 if (m) 576 m_freem(m); 577 return (error); 578 } 579 580 static void 581 udp_detach(inp) 582 struct inpcb *inp; 583 { 584 int s = splnet(); 585 586 if (inp == udp_last_inpcb) 587 udp_last_inpcb = &udb; 588 in_pcbdetach(inp); 589 splx(s); 590 } 591 592 /* 593 * Sysctl for udp variables. 594 */ 595 udp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 596 int *name; 597 u_int namelen; 598 void *oldp; 599 size_t *oldlenp; 600 void *newp; 601 size_t newlen; 602 { 603 /* All sysctl names at this level are terminal. */ 604 if (namelen != 1) 605 return (ENOTDIR); 606 607 switch (name[0]) { 608 case UDPCTL_CHECKSUM: 609 return (sysctl_int(oldp, oldlenp, newp, newlen, &udpcksum)); 610 default: 611 return (ENOPROTOOPT); 612 } 613 /* NOTREACHED */ 614 } 615