1 /* $NetBSD: tcp_usrreq.c,v 1.23 1996/05/23 17:03:29 mycroft Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)tcp_usrreq.c 8.2 (Berkeley) 1/3/94 36 */ 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/kernel.h> 41 #include <sys/malloc.h> 42 #include <sys/mbuf.h> 43 #include <sys/socket.h> 44 #include <sys/socketvar.h> 45 #include <sys/protosw.h> 46 #include <sys/errno.h> 47 #include <sys/stat.h> 48 #include <sys/proc.h> 49 #include <sys/ucred.h> 50 51 #include <vm/vm.h> 52 #include <sys/sysctl.h> 53 54 #include <net/if.h> 55 #include <net/route.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/in_var.h> 60 #include <netinet/ip.h> 61 #include <netinet/in_pcb.h> 62 #include <netinet/ip_var.h> 63 #include <netinet/tcp.h> 64 #include <netinet/tcp_fsm.h> 65 #include <netinet/tcp_seq.h> 66 #include <netinet/tcp_timer.h> 67 #include <netinet/tcp_var.h> 68 #include <netinet/tcpip.h> 69 #include <netinet/tcp_debug.h> 70 71 /* 72 * TCP protocol interface to socket abstraction. 73 */ 74 extern char *tcpstates[]; 75 76 /* 77 * Process a TCP user request for TCP tb. If this is a send request 78 * then m is the mbuf chain of send data. If this is a timer expiration 79 * (called from the software clock routine), then timertype tells which timer. 80 */ 81 /*ARGSUSED*/ 82 int 83 tcp_usrreq(so, req, m, nam, control, p) 84 struct socket *so; 85 int req; 86 struct mbuf *m, *nam, *control; 87 struct proc *p; 88 { 89 register struct inpcb *inp; 90 register struct tcpcb *tp = NULL; 91 int s; 92 int error = 0; 93 int ostate; 94 95 if (req == PRU_CONTROL) 96 return (in_control(so, (long)m, (caddr_t)nam, 97 (struct ifnet *)control, p)); 98 99 s = splsoftnet(); 100 inp = sotoinpcb(so); 101 #ifdef DIAGNOSTIC 102 if (req != PRU_SEND && req != PRU_SENDOOB && control) 103 panic("tcp_usrreq: unexpected control mbuf"); 104 #endif 105 /* 106 * When a TCP is attached to a socket, then there will be 107 * a (struct inpcb) pointed at by the socket, and this 108 * structure will point at a subsidary (struct tcpcb). 109 */ 110 if (inp == 0 && req != PRU_ATTACH) { 111 error = EINVAL; 112 goto release; 113 } 114 if (inp) { 115 tp = intotcpcb(inp); 116 /* WHAT IF TP IS 0? */ 117 #ifdef KPROF 118 tcp_acounts[tp->t_state][req]++; 119 #endif 120 ostate = tp->t_state; 121 } else 122 ostate = 0; 123 124 switch (req) { 125 126 /* 127 * TCP attaches to socket via PRU_ATTACH, reserving space, 128 * and an internet control block. 129 */ 130 case PRU_ATTACH: 131 if (inp != 0) { 132 error = EISCONN; 133 break; 134 } 135 error = tcp_attach(so); 136 if (error) 137 break; 138 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 139 so->so_linger = TCP_LINGERTIME * hz; 140 tp = sototcpcb(so); 141 break; 142 143 /* 144 * PRU_DETACH detaches the TCP protocol from the socket. 145 * If the protocol state is non-embryonic, then can't 146 * do this directly: have to initiate a PRU_DISCONNECT, 147 * which may finish later; embryonic TCB's can just 148 * be discarded here. 149 */ 150 case PRU_DETACH: 151 if (tp->t_state > TCPS_LISTEN) 152 tp = tcp_disconnect(tp); 153 else 154 tp = tcp_close(tp); 155 break; 156 157 /* 158 * Give the socket an address. 159 */ 160 case PRU_BIND: 161 error = in_pcbbind(inp, nam, p); 162 break; 163 164 /* 165 * Prepare to accept connections. 166 */ 167 case PRU_LISTEN: 168 if (inp->inp_lport == 0) { 169 error = in_pcbbind(inp, (struct mbuf *)0, 170 (struct proc *)0); 171 if (error) 172 break; 173 } 174 tp->t_state = TCPS_LISTEN; 175 break; 176 177 /* 178 * Initiate connection to peer. 179 * Create a template for use in transmissions on this connection. 180 * Enter SYN_SENT state, and mark socket as connecting. 181 * Start keep-alive timer, and seed output sequence space. 182 * Send initial segment on connection. 183 */ 184 case PRU_CONNECT: 185 if (inp->inp_lport == 0) { 186 error = in_pcbbind(inp, (struct mbuf *)0, 187 (struct proc *)0); 188 if (error) 189 break; 190 } 191 error = in_pcbconnect(inp, nam); 192 if (error) 193 break; 194 tp->t_template = tcp_template(tp); 195 if (tp->t_template == 0) { 196 in_pcbdisconnect(inp); 197 error = ENOBUFS; 198 break; 199 } 200 /* Compute window scaling to request. */ 201 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 202 (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat) 203 tp->request_r_scale++; 204 soisconnecting(so); 205 tcpstat.tcps_connattempt++; 206 tp->t_state = TCPS_SYN_SENT; 207 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; 208 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 209 tcp_sendseqinit(tp); 210 error = tcp_output(tp); 211 break; 212 213 /* 214 * Create a TCP connection between two sockets. 215 */ 216 case PRU_CONNECT2: 217 error = EOPNOTSUPP; 218 break; 219 220 /* 221 * Initiate disconnect from peer. 222 * If connection never passed embryonic stage, just drop; 223 * else if don't need to let data drain, then can just drop anyways, 224 * else have to begin TCP shutdown process: mark socket disconnecting, 225 * drain unread data, state switch to reflect user close, and 226 * send segment (e.g. FIN) to peer. Socket will be really disconnected 227 * when peer sends FIN and acks ours. 228 * 229 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 230 */ 231 case PRU_DISCONNECT: 232 tp = tcp_disconnect(tp); 233 break; 234 235 /* 236 * Accept a connection. Essentially all the work is 237 * done at higher levels; just return the address 238 * of the peer, storing through addr. 239 */ 240 case PRU_ACCEPT: 241 in_setpeeraddr(inp, nam); 242 break; 243 244 /* 245 * Mark the connection as being incapable of further output. 246 */ 247 case PRU_SHUTDOWN: 248 socantsendmore(so); 249 tp = tcp_usrclosed(tp); 250 if (tp) 251 error = tcp_output(tp); 252 break; 253 254 /* 255 * After a receive, possibly send window update to peer. 256 */ 257 case PRU_RCVD: 258 (void) tcp_output(tp); 259 break; 260 261 /* 262 * Do a send by putting data in output queue and updating urgent 263 * marker if URG set. Possibly send more data. 264 */ 265 case PRU_SEND: 266 if (control && control->m_len) { 267 m_freem(control); 268 m_freem(m); 269 error = EINVAL; 270 break; 271 } 272 sbappend(&so->so_snd, m); 273 error = tcp_output(tp); 274 break; 275 276 /* 277 * Abort the TCP. 278 */ 279 case PRU_ABORT: 280 tp = tcp_drop(tp, ECONNABORTED); 281 break; 282 283 case PRU_SENSE: 284 /* 285 * stat: don't bother with a blocksize. 286 */ 287 splx(s); 288 return (0); 289 290 case PRU_RCVOOB: 291 if (control && control->m_len) { 292 m_freem(control); 293 m_freem(m); 294 error = EINVAL; 295 break; 296 } 297 if ((so->so_oobmark == 0 && 298 (so->so_state & SS_RCVATMARK) == 0) || 299 so->so_options & SO_OOBINLINE || 300 tp->t_oobflags & TCPOOB_HADDATA) { 301 error = EINVAL; 302 break; 303 } 304 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 305 error = EWOULDBLOCK; 306 break; 307 } 308 m->m_len = 1; 309 *mtod(m, caddr_t) = tp->t_iobc; 310 if (((long)nam & MSG_PEEK) == 0) 311 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 312 break; 313 314 case PRU_SENDOOB: 315 if (sbspace(&so->so_snd) < -512) { 316 m_freem(m); 317 error = ENOBUFS; 318 break; 319 } 320 /* 321 * According to RFC961 (Assigned Protocols), 322 * the urgent pointer points to the last octet 323 * of urgent data. We continue, however, 324 * to consider it to indicate the first octet 325 * of data past the urgent section. 326 * Otherwise, snd_up should be one lower. 327 */ 328 sbappend(&so->so_snd, m); 329 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 330 tp->t_force = 1; 331 error = tcp_output(tp); 332 tp->t_force = 0; 333 break; 334 335 case PRU_SOCKADDR: 336 in_setsockaddr(inp, nam); 337 break; 338 339 case PRU_PEERADDR: 340 in_setpeeraddr(inp, nam); 341 break; 342 343 /* 344 * TCP slow timer went off; going through this 345 * routine for tracing's sake. 346 */ 347 case PRU_SLOWTIMO: 348 tp = tcp_timers(tp, (long)nam); 349 req |= (long)nam << 8; /* for debug's sake */ 350 break; 351 352 default: 353 panic("tcp_usrreq"); 354 } 355 if (tp && (so->so_options & SO_DEBUG)) 356 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 357 358 release: 359 splx(s); 360 return (error); 361 } 362 363 int 364 tcp_ctloutput(op, so, level, optname, mp) 365 int op; 366 struct socket *so; 367 int level, optname; 368 struct mbuf **mp; 369 { 370 int error = 0, s; 371 struct inpcb *inp; 372 register struct tcpcb *tp; 373 register struct mbuf *m; 374 register int i; 375 376 s = splsoftnet(); 377 inp = sotoinpcb(so); 378 if (inp == NULL) { 379 splx(s); 380 if (op == PRCO_SETOPT && *mp) 381 (void) m_free(*mp); 382 return (ECONNRESET); 383 } 384 if (level != IPPROTO_TCP) { 385 error = ip_ctloutput(op, so, level, optname, mp); 386 splx(s); 387 return (error); 388 } 389 tp = intotcpcb(inp); 390 391 switch (op) { 392 393 case PRCO_SETOPT: 394 m = *mp; 395 switch (optname) { 396 397 case TCP_NODELAY: 398 if (m == NULL || m->m_len < sizeof (int)) 399 error = EINVAL; 400 else if (*mtod(m, int *)) 401 tp->t_flags |= TF_NODELAY; 402 else 403 tp->t_flags &= ~TF_NODELAY; 404 break; 405 406 case TCP_MAXSEG: 407 if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg) 408 tp->t_maxseg = i; 409 else 410 error = EINVAL; 411 break; 412 413 default: 414 error = ENOPROTOOPT; 415 break; 416 } 417 if (m) 418 (void) m_free(m); 419 break; 420 421 case PRCO_GETOPT: 422 *mp = m = m_get(M_WAIT, MT_SOOPTS); 423 m->m_len = sizeof(int); 424 425 switch (optname) { 426 case TCP_NODELAY: 427 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 428 break; 429 case TCP_MAXSEG: 430 *mtod(m, int *) = tp->t_maxseg; 431 break; 432 default: 433 error = ENOPROTOOPT; 434 break; 435 } 436 break; 437 } 438 splx(s); 439 return (error); 440 } 441 442 #ifndef TCP_SENDSPACE 443 #define TCP_SENDSPACE 1024*16; 444 #endif 445 u_long tcp_sendspace = TCP_SENDSPACE; 446 #ifndef TCP_RECVSPACE 447 #define TCP_RECVSPACE 1024*16; 448 #endif 449 u_long tcp_recvspace = TCP_RECVSPACE; 450 451 /* 452 * Attach TCP protocol to socket, allocating 453 * internet protocol control block, tcp control block, 454 * bufer space, and entering LISTEN state if to accept connections. 455 */ 456 int 457 tcp_attach(so) 458 struct socket *so; 459 { 460 register struct tcpcb *tp; 461 struct inpcb *inp; 462 int error; 463 464 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 465 error = soreserve(so, tcp_sendspace, tcp_recvspace); 466 if (error) 467 return (error); 468 } 469 error = in_pcballoc(so, &tcbtable); 470 if (error) 471 return (error); 472 inp = sotoinpcb(so); 473 tp = tcp_newtcpcb(inp); 474 if (tp == 0) { 475 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 476 477 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 478 in_pcbdetach(inp); 479 so->so_state |= nofd; 480 return (ENOBUFS); 481 } 482 tp->t_state = TCPS_CLOSED; 483 return (0); 484 } 485 486 /* 487 * Initiate (or continue) disconnect. 488 * If embryonic state, just send reset (once). 489 * If in ``let data drain'' option and linger null, just drop. 490 * Otherwise (hard), mark socket disconnecting and drop 491 * current input data; switch states based on user close, and 492 * send segment to peer (with FIN). 493 */ 494 struct tcpcb * 495 tcp_disconnect(tp) 496 register struct tcpcb *tp; 497 { 498 struct socket *so = tp->t_inpcb->inp_socket; 499 500 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 501 tp = tcp_close(tp); 502 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 503 tp = tcp_drop(tp, 0); 504 else { 505 soisdisconnecting(so); 506 sbflush(&so->so_rcv); 507 tp = tcp_usrclosed(tp); 508 if (tp) 509 (void) tcp_output(tp); 510 } 511 return (tp); 512 } 513 514 /* 515 * User issued close, and wish to trail through shutdown states: 516 * if never received SYN, just forget it. If got a SYN from peer, 517 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 518 * If already got a FIN from peer, then almost done; go to LAST_ACK 519 * state. In all other cases, have already sent FIN to peer (e.g. 520 * after PRU_SHUTDOWN), and just have to play tedious game waiting 521 * for peer to send FIN or not respond to keep-alives, etc. 522 * We can let the user exit from the close as soon as the FIN is acked. 523 */ 524 struct tcpcb * 525 tcp_usrclosed(tp) 526 register struct tcpcb *tp; 527 { 528 529 switch (tp->t_state) { 530 531 case TCPS_CLOSED: 532 case TCPS_LISTEN: 533 case TCPS_SYN_SENT: 534 tp->t_state = TCPS_CLOSED; 535 tp = tcp_close(tp); 536 break; 537 538 case TCPS_SYN_RECEIVED: 539 case TCPS_ESTABLISHED: 540 tp->t_state = TCPS_FIN_WAIT_1; 541 break; 542 543 case TCPS_CLOSE_WAIT: 544 tp->t_state = TCPS_LAST_ACK; 545 break; 546 } 547 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) { 548 soisdisconnected(tp->t_inpcb->inp_socket); 549 /* 550 * If we are in FIN_WAIT_2, we arrived here because the 551 * application did a shutdown of the send side. Like the 552 * case of a transition from FIN_WAIT_1 to FIN_WAIT_2 after 553 * a full close, we start a timer to make sure sockets are 554 * not left in FIN_WAIT_2 forever. 555 */ 556 if (tp->t_state == TCPS_FIN_WAIT_2) 557 tp->t_timer[TCPT_2MSL] = tcp_maxidle; 558 } 559 return (tp); 560 } 561 562 /* 563 * Sysctl for tcp variables. 564 */ 565 int 566 tcp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 567 int *name; 568 u_int namelen; 569 void *oldp; 570 size_t *oldlenp; 571 void *newp; 572 size_t newlen; 573 { 574 575 /* All sysctl names at this level are terminal. */ 576 if (namelen != 1) 577 return (ENOTDIR); 578 579 switch (name[0]) { 580 case TCPCTL_RFC1323: 581 return (sysctl_int(oldp, oldlenp, newp, newlen, 582 &tcp_do_rfc1323)); 583 584 default: 585 return (ENOPROTOOPT); 586 } 587 /* NOTREACHED */ 588 } 589