1 /* $NetBSD: tcp_usrreq.c,v 1.27 1997/10/10 01:51:11 explorer 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 #include "opt_tcp_recvspace.h" 72 #include "opt_tcp_sendspace.h" 73 74 /* 75 * TCP protocol interface to socket abstraction. 76 */ 77 extern char *tcpstates[]; 78 79 /* 80 * Process a TCP user request for TCP tb. If this is a send request 81 * then m is the mbuf chain of send data. If this is a timer expiration 82 * (called from the software clock routine), then timertype tells which timer. 83 */ 84 /*ARGSUSED*/ 85 int 86 tcp_usrreq(so, req, m, nam, control, p) 87 struct socket *so; 88 int req; 89 struct mbuf *m, *nam, *control; 90 struct proc *p; 91 { 92 register struct inpcb *inp; 93 register struct tcpcb *tp = NULL; 94 int s; 95 int error = 0; 96 int ostate; 97 98 if (req == PRU_CONTROL) 99 return (in_control(so, (long)m, (caddr_t)nam, 100 (struct ifnet *)control, p)); 101 102 s = splsoftnet(); 103 inp = sotoinpcb(so); 104 #ifdef DIAGNOSTIC 105 if (req != PRU_SEND && req != PRU_SENDOOB && control) 106 panic("tcp_usrreq: unexpected control mbuf"); 107 #endif 108 /* 109 * When a TCP is attached to a socket, then there will be 110 * a (struct inpcb) pointed at by the socket, and this 111 * structure will point at a subsidary (struct tcpcb). 112 */ 113 if (inp == 0 && req != PRU_ATTACH) { 114 error = EINVAL; 115 goto release; 116 } 117 if (inp) { 118 tp = intotcpcb(inp); 119 /* WHAT IF TP IS 0? */ 120 #ifdef KPROF 121 tcp_acounts[tp->t_state][req]++; 122 #endif 123 ostate = tp->t_state; 124 } else 125 ostate = 0; 126 127 switch (req) { 128 129 /* 130 * TCP attaches to socket via PRU_ATTACH, reserving space, 131 * and an internet control block. 132 */ 133 case PRU_ATTACH: 134 if (inp != 0) { 135 error = EISCONN; 136 break; 137 } 138 error = tcp_attach(so); 139 if (error) 140 break; 141 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 142 so->so_linger = TCP_LINGERTIME * hz; 143 tp = sototcpcb(so); 144 break; 145 146 /* 147 * PRU_DETACH detaches the TCP protocol from the socket. 148 */ 149 case PRU_DETACH: 150 tp = tcp_disconnect(tp); 151 break; 152 153 /* 154 * Give the socket an address. 155 */ 156 case PRU_BIND: 157 error = in_pcbbind(inp, nam, p); 158 break; 159 160 /* 161 * Prepare to accept connections. 162 */ 163 case PRU_LISTEN: 164 if (inp->inp_lport == 0) { 165 error = in_pcbbind(inp, (struct mbuf *)0, 166 (struct proc *)0); 167 if (error) 168 break; 169 } 170 tp->t_state = TCPS_LISTEN; 171 break; 172 173 /* 174 * Initiate connection to peer. 175 * Create a template for use in transmissions on this connection. 176 * Enter SYN_SENT state, and mark socket as connecting. 177 * Start keep-alive timer, and seed output sequence space. 178 * Send initial segment on connection. 179 */ 180 case PRU_CONNECT: 181 if (inp->inp_lport == 0) { 182 error = in_pcbbind(inp, (struct mbuf *)0, 183 (struct proc *)0); 184 if (error) 185 break; 186 } 187 error = in_pcbconnect(inp, nam); 188 if (error) 189 break; 190 tp->t_template = tcp_template(tp); 191 if (tp->t_template == 0) { 192 in_pcbdisconnect(inp); 193 error = ENOBUFS; 194 break; 195 } 196 /* Compute window scaling to request. */ 197 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 198 (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat) 199 tp->request_r_scale++; 200 soisconnecting(so); 201 tcpstat.tcps_connattempt++; 202 tp->t_state = TCPS_SYN_SENT; 203 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; 204 tp->iss = tcp_new_iss(tp, sizeof(struct tcpcb), 0); 205 tcp_sendseqinit(tp); 206 error = tcp_output(tp); 207 break; 208 209 /* 210 * Create a TCP connection between two sockets. 211 */ 212 case PRU_CONNECT2: 213 error = EOPNOTSUPP; 214 break; 215 216 /* 217 * Initiate disconnect from peer. 218 * If connection never passed embryonic stage, just drop; 219 * else if don't need to let data drain, then can just drop anyways, 220 * else have to begin TCP shutdown process: mark socket disconnecting, 221 * drain unread data, state switch to reflect user close, and 222 * send segment (e.g. FIN) to peer. Socket will be really disconnected 223 * when peer sends FIN and acks ours. 224 * 225 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 226 */ 227 case PRU_DISCONNECT: 228 tp = tcp_disconnect(tp); 229 break; 230 231 /* 232 * Accept a connection. Essentially all the work is 233 * done at higher levels; just return the address 234 * of the peer, storing through addr. 235 */ 236 case PRU_ACCEPT: 237 in_setpeeraddr(inp, nam); 238 break; 239 240 /* 241 * Mark the connection as being incapable of further output. 242 */ 243 case PRU_SHUTDOWN: 244 socantsendmore(so); 245 tp = tcp_usrclosed(tp); 246 if (tp) 247 error = tcp_output(tp); 248 break; 249 250 /* 251 * After a receive, possibly send window update to peer. 252 */ 253 case PRU_RCVD: 254 (void) tcp_output(tp); 255 break; 256 257 /* 258 * Do a send by putting data in output queue and updating urgent 259 * marker if URG set. Possibly send more data. 260 */ 261 case PRU_SEND: 262 if (control && control->m_len) { 263 m_freem(control); 264 m_freem(m); 265 error = EINVAL; 266 break; 267 } 268 sbappend(&so->so_snd, m); 269 error = tcp_output(tp); 270 break; 271 272 /* 273 * Abort the TCP. 274 */ 275 case PRU_ABORT: 276 tp = tcp_drop(tp, ECONNABORTED); 277 break; 278 279 case PRU_SENSE: 280 /* 281 * stat: don't bother with a blocksize. 282 */ 283 splx(s); 284 return (0); 285 286 case PRU_RCVOOB: 287 if (control && control->m_len) { 288 m_freem(control); 289 m_freem(m); 290 error = EINVAL; 291 break; 292 } 293 if ((so->so_oobmark == 0 && 294 (so->so_state & SS_RCVATMARK) == 0) || 295 so->so_options & SO_OOBINLINE || 296 tp->t_oobflags & TCPOOB_HADDATA) { 297 error = EINVAL; 298 break; 299 } 300 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 301 error = EWOULDBLOCK; 302 break; 303 } 304 m->m_len = 1; 305 *mtod(m, caddr_t) = tp->t_iobc; 306 if (((long)nam & MSG_PEEK) == 0) 307 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 308 break; 309 310 case PRU_SENDOOB: 311 if (sbspace(&so->so_snd) < -512) { 312 m_freem(m); 313 error = ENOBUFS; 314 break; 315 } 316 /* 317 * According to RFC961 (Assigned Protocols), 318 * the urgent pointer points to the last octet 319 * of urgent data. We continue, however, 320 * to consider it to indicate the first octet 321 * of data past the urgent section. 322 * Otherwise, snd_up should be one lower. 323 */ 324 sbappend(&so->so_snd, m); 325 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 326 tp->t_force = 1; 327 error = tcp_output(tp); 328 tp->t_force = 0; 329 break; 330 331 case PRU_SOCKADDR: 332 in_setsockaddr(inp, nam); 333 break; 334 335 case PRU_PEERADDR: 336 in_setpeeraddr(inp, nam); 337 break; 338 339 /* 340 * TCP slow timer went off; going through this 341 * routine for tracing's sake. 342 */ 343 case PRU_SLOWTIMO: 344 tp = tcp_timers(tp, (long)nam); 345 req |= (long)nam << 8; /* for debug's sake */ 346 break; 347 348 default: 349 panic("tcp_usrreq"); 350 } 351 if (tp && (so->so_options & SO_DEBUG)) 352 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 353 354 release: 355 splx(s); 356 return (error); 357 } 358 359 int 360 tcp_ctloutput(op, so, level, optname, mp) 361 int op; 362 struct socket *so; 363 int level, optname; 364 struct mbuf **mp; 365 { 366 int error = 0, s; 367 struct inpcb *inp; 368 register struct tcpcb *tp; 369 register struct mbuf *m; 370 register int i; 371 372 s = splsoftnet(); 373 inp = sotoinpcb(so); 374 if (inp == NULL) { 375 splx(s); 376 if (op == PRCO_SETOPT && *mp) 377 (void) m_free(*mp); 378 return (ECONNRESET); 379 } 380 if (level != IPPROTO_TCP) { 381 error = ip_ctloutput(op, so, level, optname, mp); 382 splx(s); 383 return (error); 384 } 385 tp = intotcpcb(inp); 386 387 switch (op) { 388 389 case PRCO_SETOPT: 390 m = *mp; 391 switch (optname) { 392 393 case TCP_NODELAY: 394 if (m == NULL || m->m_len < sizeof (int)) 395 error = EINVAL; 396 else if (*mtod(m, int *)) 397 tp->t_flags |= TF_NODELAY; 398 else 399 tp->t_flags &= ~TF_NODELAY; 400 break; 401 402 case TCP_MAXSEG: 403 if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg) 404 tp->t_maxseg = i; 405 else 406 error = EINVAL; 407 break; 408 409 default: 410 error = ENOPROTOOPT; 411 break; 412 } 413 if (m) 414 (void) m_free(m); 415 break; 416 417 case PRCO_GETOPT: 418 *mp = m = m_get(M_WAIT, MT_SOOPTS); 419 m->m_len = sizeof(int); 420 421 switch (optname) { 422 case TCP_NODELAY: 423 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 424 break; 425 case TCP_MAXSEG: 426 *mtod(m, int *) = tp->t_maxseg; 427 break; 428 default: 429 error = ENOPROTOOPT; 430 break; 431 } 432 break; 433 } 434 splx(s); 435 return (error); 436 } 437 438 #ifndef TCP_SENDSPACE 439 #define TCP_SENDSPACE 1024*16; 440 #endif 441 int tcp_sendspace = TCP_SENDSPACE; 442 #ifndef TCP_RECVSPACE 443 #define TCP_RECVSPACE 1024*16; 444 #endif 445 int tcp_recvspace = TCP_RECVSPACE; 446 447 /* 448 * Attach TCP protocol to socket, allocating 449 * internet protocol control block, tcp control block, 450 * bufer space, and entering LISTEN state if to accept connections. 451 */ 452 int 453 tcp_attach(so) 454 struct socket *so; 455 { 456 register struct tcpcb *tp; 457 struct inpcb *inp; 458 int error; 459 460 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 461 error = soreserve(so, tcp_sendspace, tcp_recvspace); 462 if (error) 463 return (error); 464 } 465 error = in_pcballoc(so, &tcbtable); 466 if (error) 467 return (error); 468 inp = sotoinpcb(so); 469 tp = tcp_newtcpcb(inp); 470 if (tp == 0) { 471 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 472 473 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 474 in_pcbdetach(inp); 475 so->so_state |= nofd; 476 return (ENOBUFS); 477 } 478 tp->t_state = TCPS_CLOSED; 479 return (0); 480 } 481 482 /* 483 * Initiate (or continue) disconnect. 484 * If embryonic state, just send reset (once). 485 * If in ``let data drain'' option and linger null, just drop. 486 * Otherwise (hard), mark socket disconnecting and drop 487 * current input data; switch states based on user close, and 488 * send segment to peer (with FIN). 489 */ 490 struct tcpcb * 491 tcp_disconnect(tp) 492 register struct tcpcb *tp; 493 { 494 struct socket *so = tp->t_inpcb->inp_socket; 495 496 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 497 tp = tcp_close(tp); 498 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 499 tp = tcp_drop(tp, 0); 500 else { 501 soisdisconnecting(so); 502 sbflush(&so->so_rcv); 503 tp = tcp_usrclosed(tp); 504 if (tp) 505 (void) tcp_output(tp); 506 } 507 return (tp); 508 } 509 510 /* 511 * User issued close, and wish to trail through shutdown states: 512 * if never received SYN, just forget it. If got a SYN from peer, 513 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 514 * If already got a FIN from peer, then almost done; go to LAST_ACK 515 * state. In all other cases, have already sent FIN to peer (e.g. 516 * after PRU_SHUTDOWN), and just have to play tedious game waiting 517 * for peer to send FIN or not respond to keep-alives, etc. 518 * We can let the user exit from the close as soon as the FIN is acked. 519 */ 520 struct tcpcb * 521 tcp_usrclosed(tp) 522 register struct tcpcb *tp; 523 { 524 525 switch (tp->t_state) { 526 527 case TCPS_CLOSED: 528 case TCPS_LISTEN: 529 case TCPS_SYN_SENT: 530 tp->t_state = TCPS_CLOSED; 531 tp = tcp_close(tp); 532 break; 533 534 case TCPS_SYN_RECEIVED: 535 case TCPS_ESTABLISHED: 536 tp->t_state = TCPS_FIN_WAIT_1; 537 break; 538 539 case TCPS_CLOSE_WAIT: 540 tp->t_state = TCPS_LAST_ACK; 541 break; 542 } 543 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) { 544 soisdisconnected(tp->t_inpcb->inp_socket); 545 /* 546 * If we are in FIN_WAIT_2, we arrived here because the 547 * application did a shutdown of the send side. Like the 548 * case of a transition from FIN_WAIT_1 to FIN_WAIT_2 after 549 * a full close, we start a timer to make sure sockets are 550 * not left in FIN_WAIT_2 forever. 551 */ 552 if (tp->t_state == TCPS_FIN_WAIT_2) 553 tp->t_timer[TCPT_2MSL] = tcp_maxidle; 554 } 555 return (tp); 556 } 557 558 /* 559 * Sysctl for tcp variables. 560 */ 561 int 562 tcp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 563 int *name; 564 u_int namelen; 565 void *oldp; 566 size_t *oldlenp; 567 void *newp; 568 size_t newlen; 569 { 570 571 /* All sysctl names at this level are terminal. */ 572 if (namelen != 1) 573 return (ENOTDIR); 574 575 switch (name[0]) { 576 case TCPCTL_RFC1323: 577 return (sysctl_int(oldp, oldlenp, newp, newlen, 578 &tcp_do_rfc1323)); 579 case TCPCTL_SENDSPACE: 580 return (sysctl_int(oldp, oldlenp, newp, newlen, 581 &tcp_sendspace)); 582 case TCPCTL_RECVSPACE: 583 return (sysctl_int(oldp, oldlenp, newp, newlen, 584 &tcp_recvspace)); 585 case TCPCTL_MSSDFLT: 586 return (sysctl_int(oldp, oldlenp, newp, newlen, 587 &tcp_mssdflt)); 588 case TCPCTL_SYN_CACHE_LIMIT: 589 return (sysctl_int(oldp, oldlenp, newp, newlen, 590 &tcp_syn_cache_limit)); 591 case TCPCTL_SYN_BUCKET_LIMIT: 592 return (sysctl_int(oldp, oldlenp, newp, newlen, 593 &tcp_syn_bucket_limit)); 594 case TCPCTL_SYN_CACHE_INTER: 595 return (sysctl_int(oldp, oldlenp, newp, newlen, 596 &tcp_syn_cache_interval)); 597 default: 598 return (ENOPROTOOPT); 599 } 600 /* NOTREACHED */ 601 } 602