1 /* 2 * Copyright (c) 1982, 1986, 1988, 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 * @(#)tcp_usrreq.c 8.2 (Berkeley) 1/3/94 34 * $Id: tcp_usrreq.c,v 1.5 1994/09/15 10:36:56 davidg Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/malloc.h> 40 #include <sys/mbuf.h> 41 #include <sys/socket.h> 42 #include <sys/socketvar.h> 43 #include <sys/protosw.h> 44 #include <sys/errno.h> 45 #include <sys/stat.h> 46 47 #include <net/if.h> 48 #include <net/route.h> 49 50 #include <netinet/in.h> 51 #include <netinet/in_systm.h> 52 #include <netinet/ip.h> 53 #include <netinet/in_pcb.h> 54 #include <netinet/ip_var.h> 55 #include <netinet/tcp.h> 56 #include <netinet/tcp_fsm.h> 57 #include <netinet/tcp_seq.h> 58 #include <netinet/tcp_timer.h> 59 #include <netinet/tcp_var.h> 60 #include <netinet/tcpip.h> 61 #ifdef TCPDEBUG 62 #include <netinet/tcp_debug.h> 63 #endif 64 65 /* 66 * TCP protocol interface to socket abstraction. 67 */ 68 extern char *tcpstates[]; 69 70 /* 71 * Process a TCP user request for TCP tb. If this is a send request 72 * then m is the mbuf chain of send data. If this is a timer expiration 73 * (called from the software clock routine), then timertype tells which timer. 74 */ 75 /*ARGSUSED*/ 76 int 77 tcp_usrreq(so, req, m, nam, control) 78 struct socket *so; 79 int req; 80 struct mbuf *m, *nam, *control; 81 { 82 register struct inpcb *inp; 83 register struct tcpcb *tp = 0; 84 struct sockaddr_in *sinp; 85 int s; 86 int error = 0; 87 int ostate; 88 89 if (req == PRU_CONTROL) 90 return (in_control(so, (int)m, (caddr_t)nam, 91 (struct ifnet *)control)); 92 if (control && control->m_len) { 93 m_freem(control); 94 if (m) 95 m_freem(m); 96 return (EINVAL); 97 } 98 99 s = splnet(); 100 inp = sotoinpcb(so); 101 /* 102 * When a TCP is attached to a socket, then there will be 103 * a (struct inpcb) pointed at by the socket, and this 104 * structure will point at a subsidary (struct tcpcb). 105 */ 106 if (inp == 0 && req != PRU_ATTACH) { 107 splx(s); 108 return (EINVAL); /* XXX */ 109 } 110 if (inp) { 111 tp = intotcpcb(inp); 112 /* WHAT IF TP IS 0? */ 113 #ifdef KPROF 114 tcp_acounts[tp->t_state][req]++; 115 #endif 116 ostate = tp->t_state; 117 } else 118 ostate = 0; 119 switch (req) { 120 121 /* 122 * TCP attaches to socket via PRU_ATTACH, reserving space, 123 * and an internet control block. 124 */ 125 case PRU_ATTACH: 126 if (inp) { 127 error = EISCONN; 128 break; 129 } 130 error = tcp_attach(so); 131 if (error) 132 break; 133 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 134 so->so_linger = TCP_LINGERTIME; 135 tp = sototcpcb(so); 136 break; 137 138 /* 139 * PRU_DETACH detaches the TCP protocol from the socket. 140 * If the protocol state is non-embryonic, then can't 141 * do this directly: have to initiate a PRU_DISCONNECT, 142 * which may finish later; embryonic TCB's can just 143 * be discarded here. 144 */ 145 case PRU_DETACH: 146 if (tp->t_state > TCPS_LISTEN) 147 tp = tcp_disconnect(tp); 148 else 149 tp = tcp_close(tp); 150 break; 151 152 /* 153 * Give the socket an address. 154 */ 155 case PRU_BIND: 156 /* 157 * Must check for multicast addresses and disallow binding 158 * to them. 159 */ 160 sinp = mtod(nam, struct sockaddr_in *); 161 if (sinp->sin_family == AF_INET && 162 IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) { 163 error = EAFNOSUPPORT; 164 break; 165 } 166 error = in_pcbbind(inp, nam); 167 if (error) 168 break; 169 break; 170 171 /* 172 * Prepare to accept connections. 173 */ 174 case PRU_LISTEN: 175 if (inp->inp_lport == 0) 176 error = in_pcbbind(inp, (struct mbuf *)0); 177 if (error == 0) 178 tp->t_state = TCPS_LISTEN; 179 break; 180 181 /* 182 * Initiate connection to peer. 183 * Create a template for use in transmissions on this connection. 184 * Enter SYN_SENT state, and mark socket as connecting. 185 * Start keep-alive timer, and seed output sequence space. 186 * Send initial segment on connection. 187 */ 188 case PRU_CONNECT: 189 /* 190 * Must disallow TCP ``connections'' to multicast addresses. 191 */ 192 sinp = mtod(nam, struct sockaddr_in *); 193 if (sinp->sin_family == AF_INET 194 && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) { 195 error = EAFNOSUPPORT; 196 break; 197 } 198 199 if (inp->inp_lport == 0) { 200 error = in_pcbbind(inp, (struct mbuf *)0); 201 if (error) 202 break; 203 } 204 error = in_pcbconnect(inp, nam); 205 if (error) 206 break; 207 tp->t_template = tcp_template(tp); 208 if (tp->t_template == 0) { 209 in_pcbdisconnect(inp); 210 error = ENOBUFS; 211 break; 212 } 213 /* Compute window scaling to request. */ 214 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 215 (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat) 216 tp->request_r_scale++; 217 soisconnecting(so); 218 tcpstat.tcps_connattempt++; 219 tp->t_state = TCPS_SYN_SENT; 220 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; 221 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 222 tcp_sendseqinit(tp); 223 error = tcp_output(tp); 224 break; 225 226 /* 227 * Create a TCP connection between two sockets. 228 */ 229 case PRU_CONNECT2: 230 error = EOPNOTSUPP; 231 break; 232 233 /* 234 * Initiate disconnect from peer. 235 * If connection never passed embryonic stage, just drop; 236 * else if don't need to let data drain, then can just drop anyways, 237 * else have to begin TCP shutdown process: mark socket disconnecting, 238 * drain unread data, state switch to reflect user close, and 239 * send segment (e.g. FIN) to peer. Socket will be really disconnected 240 * when peer sends FIN and acks ours. 241 * 242 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 243 */ 244 case PRU_DISCONNECT: 245 tp = tcp_disconnect(tp); 246 break; 247 248 /* 249 * Accept a connection. Essentially all the work is 250 * done at higher levels; just return the address 251 * of the peer, storing through addr. 252 */ 253 case PRU_ACCEPT: 254 in_setpeeraddr(inp, nam); 255 break; 256 257 /* 258 * Mark the connection as being incapable of further output. 259 */ 260 case PRU_SHUTDOWN: 261 socantsendmore(so); 262 tp = tcp_usrclosed(tp); 263 if (tp) 264 error = tcp_output(tp); 265 break; 266 267 /* 268 * After a receive, possibly send window update to peer. 269 */ 270 case PRU_RCVD: 271 (void) tcp_output(tp); 272 break; 273 274 /* 275 * Do a send by putting data in output queue and updating urgent 276 * marker if URG set. Possibly send more data. 277 */ 278 case PRU_SEND: 279 sbappend(&so->so_snd, m); 280 error = tcp_output(tp); 281 break; 282 283 /* 284 * Abort the TCP. 285 */ 286 case PRU_ABORT: 287 tp = tcp_drop(tp, ECONNABORTED); 288 break; 289 290 case PRU_SENSE: 291 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 292 (void) splx(s); 293 return (0); 294 295 case PRU_RCVOOB: 296 if ((so->so_oobmark == 0 && 297 (so->so_state & SS_RCVATMARK) == 0) || 298 so->so_options & SO_OOBINLINE || 299 tp->t_oobflags & TCPOOB_HADDATA) { 300 error = EINVAL; 301 break; 302 } 303 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 304 error = EWOULDBLOCK; 305 break; 306 } 307 m->m_len = 1; 308 *mtod(m, caddr_t) = tp->t_iobc; 309 if (((int)nam & MSG_PEEK) == 0) 310 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 311 break; 312 313 case PRU_SENDOOB: 314 if (sbspace(&so->so_snd) < -512) { 315 m_freem(m); 316 error = ENOBUFS; 317 break; 318 } 319 /* 320 * According to RFC961 (Assigned Protocols), 321 * the urgent pointer points to the last octet 322 * of urgent data. We continue, however, 323 * to consider it to indicate the first octet 324 * of data past the urgent section. 325 * Otherwise, snd_up should be one lower. 326 */ 327 sbappend(&so->so_snd, m); 328 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 329 tp->t_force = 1; 330 error = tcp_output(tp); 331 tp->t_force = 0; 332 break; 333 334 case PRU_SOCKADDR: 335 in_setsockaddr(inp, nam); 336 break; 337 338 case PRU_PEERADDR: 339 in_setpeeraddr(inp, nam); 340 break; 341 342 /* 343 * TCP slow timer went off; going through this 344 * routine for tracing's sake. 345 */ 346 case PRU_SLOWTIMO: 347 tp = tcp_timers(tp, (int)nam); 348 req |= (int)nam << 8; /* for debug's sake */ 349 break; 350 351 default: 352 panic("tcp_usrreq"); 353 } 354 #ifdef TCPDEBUG 355 if (tp && (so->so_options & SO_DEBUG)) 356 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 357 #endif 358 splx(s); 359 return (error); 360 } 361 362 int 363 tcp_ctloutput(op, so, level, optname, mp) 364 int op; 365 struct socket *so; 366 int level, optname; 367 struct mbuf **mp; 368 { 369 int error = 0, s; 370 struct inpcb *inp; 371 register struct tcpcb *tp; 372 register struct mbuf *m; 373 register int i; 374 375 s = splnet(); 376 inp = sotoinpcb(so); 377 if (inp == NULL) { 378 splx(s); 379 if (op == PRCO_SETOPT && *mp) 380 (void) m_free(*mp); 381 return (ECONNRESET); 382 } 383 if (level != IPPROTO_TCP) { 384 error = ip_ctloutput(op, so, level, optname, mp); 385 splx(s); 386 return (error); 387 } 388 tp = intotcpcb(inp); 389 390 switch (op) { 391 392 case PRCO_SETOPT: 393 m = *mp; 394 switch (optname) { 395 396 case TCP_NODELAY: 397 if (m == NULL || m->m_len < sizeof (int)) 398 error = EINVAL; 399 else if (*mtod(m, int *)) 400 tp->t_flags |= TF_NODELAY; 401 else 402 tp->t_flags &= ~TF_NODELAY; 403 break; 404 405 case TCP_MAXSEG: 406 if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg) 407 tp->t_maxseg = i; 408 else 409 error = EINVAL; 410 break; 411 412 default: 413 error = ENOPROTOOPT; 414 break; 415 } 416 if (m) 417 (void) m_free(m); 418 break; 419 420 case PRCO_GETOPT: 421 *mp = m = m_get(M_WAIT, MT_SOOPTS); 422 m->m_len = sizeof(int); 423 424 switch (optname) { 425 case TCP_NODELAY: 426 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 427 break; 428 case TCP_MAXSEG: 429 *mtod(m, int *) = tp->t_maxseg; 430 break; 431 default: 432 error = ENOPROTOOPT; 433 break; 434 } 435 break; 436 } 437 splx(s); 438 return (error); 439 } 440 441 /* 442 * tcp_sendspace and tcp_recvspace are the default send and receive window 443 * sizes, respectively. These are obsolescent (this information should 444 * be set by the route). 445 */ 446 #ifdef TCP_SMALLSPACE 447 u_long tcp_sendspace = 1024*4; 448 u_long tcp_recvspace = 1024*4; 449 #else 450 u_long tcp_sendspace = 1024*16; 451 u_long tcp_recvspace = 1024*16; 452 #endif 453 454 /* 455 * Attach TCP protocol to socket, allocating 456 * internet protocol control block, tcp control block, 457 * bufer space, and entering LISTEN state if to accept connections. 458 */ 459 int 460 tcp_attach(so) 461 struct socket *so; 462 { 463 register struct tcpcb *tp; 464 struct inpcb *inp; 465 int error; 466 467 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 468 error = soreserve(so, tcp_sendspace, tcp_recvspace); 469 if (error) 470 return (error); 471 } 472 error = in_pcballoc(so, &tcb); 473 if (error) 474 return (error); 475 inp = sotoinpcb(so); 476 tp = tcp_newtcpcb(inp); 477 if (tp == 0) { 478 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 479 480 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 481 in_pcbdetach(inp); 482 so->so_state |= nofd; 483 return (ENOBUFS); 484 } 485 tp->t_state = TCPS_CLOSED; 486 return (0); 487 } 488 489 /* 490 * Initiate (or continue) disconnect. 491 * If embryonic state, just send reset (once). 492 * If in ``let data drain'' option and linger null, just drop. 493 * Otherwise (hard), mark socket disconnecting and drop 494 * current input data; switch states based on user close, and 495 * send segment to peer (with FIN). 496 */ 497 struct tcpcb * 498 tcp_disconnect(tp) 499 register struct tcpcb *tp; 500 { 501 struct socket *so = tp->t_inpcb->inp_socket; 502 503 if (tp->t_state < TCPS_ESTABLISHED) 504 tp = tcp_close(tp); 505 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 506 tp = tcp_drop(tp, 0); 507 else { 508 soisdisconnecting(so); 509 sbflush(&so->so_rcv); 510 tp = tcp_usrclosed(tp); 511 if (tp) 512 (void) tcp_output(tp); 513 } 514 return (tp); 515 } 516 517 /* 518 * User issued close, and wish to trail through shutdown states: 519 * if never received SYN, just forget it. If got a SYN from peer, 520 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 521 * If already got a FIN from peer, then almost done; go to LAST_ACK 522 * state. In all other cases, have already sent FIN to peer (e.g. 523 * after PRU_SHUTDOWN), and just have to play tedious game waiting 524 * for peer to send FIN or not respond to keep-alives, etc. 525 * We can let the user exit from the close as soon as the FIN is acked. 526 */ 527 struct tcpcb * 528 tcp_usrclosed(tp) 529 register struct tcpcb *tp; 530 { 531 532 switch (tp->t_state) { 533 534 case TCPS_CLOSED: 535 case TCPS_LISTEN: 536 case TCPS_SYN_SENT: 537 tp->t_state = TCPS_CLOSED; 538 tp = tcp_close(tp); 539 break; 540 541 case TCPS_SYN_RECEIVED: 542 case TCPS_ESTABLISHED: 543 tp->t_state = TCPS_FIN_WAIT_1; 544 break; 545 546 case TCPS_CLOSE_WAIT: 547 tp->t_state = TCPS_LAST_ACK; 548 break; 549 } 550 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 551 soisdisconnected(tp->t_inpcb->inp_socket); 552 return (tp); 553 } 554