tcp_usrreq.c revision 1.25
1 /* $NetBSD: tcp_usrreq.c,v 1.25 1997/07/28 22:18:48 thorpej 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 */ 146 case PRU_DETACH: 147 tp = tcp_disconnect(tp); 148 break; 149 150 /* 151 * Give the socket an address. 152 */ 153 case PRU_BIND: 154 error = in_pcbbind(inp, nam, p); 155 break; 156 157 /* 158 * Prepare to accept connections. 159 */ 160 case PRU_LISTEN: 161 if (inp->inp_lport == 0) { 162 error = in_pcbbind(inp, (struct mbuf *)0, 163 (struct proc *)0); 164 if (error) 165 break; 166 } 167 tp->t_state = TCPS_LISTEN; 168 break; 169 170 /* 171 * Initiate connection to peer. 172 * Create a template for use in transmissions on this connection. 173 * Enter SYN_SENT state, and mark socket as connecting. 174 * Start keep-alive timer, and seed output sequence space. 175 * Send initial segment on connection. 176 */ 177 case PRU_CONNECT: 178 if (inp->inp_lport == 0) { 179 error = in_pcbbind(inp, (struct mbuf *)0, 180 (struct proc *)0); 181 if (error) 182 break; 183 } 184 error = in_pcbconnect(inp, nam); 185 if (error) 186 break; 187 tp->t_template = tcp_template(tp); 188 if (tp->t_template == 0) { 189 in_pcbdisconnect(inp); 190 error = ENOBUFS; 191 break; 192 } 193 /* Compute window scaling to request. */ 194 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 195 (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat) 196 tp->request_r_scale++; 197 soisconnecting(so); 198 tcpstat.tcps_connattempt++; 199 tp->t_state = TCPS_SYN_SENT; 200 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; 201 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 202 tcp_sendseqinit(tp); 203 error = tcp_output(tp); 204 break; 205 206 /* 207 * Create a TCP connection between two sockets. 208 */ 209 case PRU_CONNECT2: 210 error = EOPNOTSUPP; 211 break; 212 213 /* 214 * Initiate disconnect from peer. 215 * If connection never passed embryonic stage, just drop; 216 * else if don't need to let data drain, then can just drop anyways, 217 * else have to begin TCP shutdown process: mark socket disconnecting, 218 * drain unread data, state switch to reflect user close, and 219 * send segment (e.g. FIN) to peer. Socket will be really disconnected 220 * when peer sends FIN and acks ours. 221 * 222 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 223 */ 224 case PRU_DISCONNECT: 225 tp = tcp_disconnect(tp); 226 break; 227 228 /* 229 * Accept a connection. Essentially all the work is 230 * done at higher levels; just return the address 231 * of the peer, storing through addr. 232 */ 233 case PRU_ACCEPT: 234 in_setpeeraddr(inp, nam); 235 break; 236 237 /* 238 * Mark the connection as being incapable of further output. 239 */ 240 case PRU_SHUTDOWN: 241 socantsendmore(so); 242 tp = tcp_usrclosed(tp); 243 if (tp) 244 error = tcp_output(tp); 245 break; 246 247 /* 248 * After a receive, possibly send window update to peer. 249 */ 250 case PRU_RCVD: 251 (void) tcp_output(tp); 252 break; 253 254 /* 255 * Do a send by putting data in output queue and updating urgent 256 * marker if URG set. Possibly send more data. 257 */ 258 case PRU_SEND: 259 if (control && control->m_len) { 260 m_freem(control); 261 m_freem(m); 262 error = EINVAL; 263 break; 264 } 265 sbappend(&so->so_snd, m); 266 error = tcp_output(tp); 267 break; 268 269 /* 270 * Abort the TCP. 271 */ 272 case PRU_ABORT: 273 tp = tcp_drop(tp, ECONNABORTED); 274 break; 275 276 case PRU_SENSE: 277 /* 278 * stat: don't bother with a blocksize. 279 */ 280 splx(s); 281 return (0); 282 283 case PRU_RCVOOB: 284 if (control && control->m_len) { 285 m_freem(control); 286 m_freem(m); 287 error = EINVAL; 288 break; 289 } 290 if ((so->so_oobmark == 0 && 291 (so->so_state & SS_RCVATMARK) == 0) || 292 so->so_options & SO_OOBINLINE || 293 tp->t_oobflags & TCPOOB_HADDATA) { 294 error = EINVAL; 295 break; 296 } 297 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 298 error = EWOULDBLOCK; 299 break; 300 } 301 m->m_len = 1; 302 *mtod(m, caddr_t) = tp->t_iobc; 303 if (((long)nam & MSG_PEEK) == 0) 304 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 305 break; 306 307 case PRU_SENDOOB: 308 if (sbspace(&so->so_snd) < -512) { 309 m_freem(m); 310 error = ENOBUFS; 311 break; 312 } 313 /* 314 * According to RFC961 (Assigned Protocols), 315 * the urgent pointer points to the last octet 316 * of urgent data. We continue, however, 317 * to consider it to indicate the first octet 318 * of data past the urgent section. 319 * Otherwise, snd_up should be one lower. 320 */ 321 sbappend(&so->so_snd, m); 322 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 323 tp->t_force = 1; 324 error = tcp_output(tp); 325 tp->t_force = 0; 326 break; 327 328 case PRU_SOCKADDR: 329 in_setsockaddr(inp, nam); 330 break; 331 332 case PRU_PEERADDR: 333 in_setpeeraddr(inp, nam); 334 break; 335 336 /* 337 * TCP slow timer went off; going through this 338 * routine for tracing's sake. 339 */ 340 case PRU_SLOWTIMO: 341 tp = tcp_timers(tp, (long)nam); 342 req |= (long)nam << 8; /* for debug's sake */ 343 break; 344 345 default: 346 panic("tcp_usrreq"); 347 } 348 if (tp && (so->so_options & SO_DEBUG)) 349 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 350 351 release: 352 splx(s); 353 return (error); 354 } 355 356 int 357 tcp_ctloutput(op, so, level, optname, mp) 358 int op; 359 struct socket *so; 360 int level, optname; 361 struct mbuf **mp; 362 { 363 int error = 0, s; 364 struct inpcb *inp; 365 register struct tcpcb *tp; 366 register struct mbuf *m; 367 register int i; 368 369 s = splsoftnet(); 370 inp = sotoinpcb(so); 371 if (inp == NULL) { 372 splx(s); 373 if (op == PRCO_SETOPT && *mp) 374 (void) m_free(*mp); 375 return (ECONNRESET); 376 } 377 if (level != IPPROTO_TCP) { 378 error = ip_ctloutput(op, so, level, optname, mp); 379 splx(s); 380 return (error); 381 } 382 tp = intotcpcb(inp); 383 384 switch (op) { 385 386 case PRCO_SETOPT: 387 m = *mp; 388 switch (optname) { 389 390 case TCP_NODELAY: 391 if (m == NULL || m->m_len < sizeof (int)) 392 error = EINVAL; 393 else if (*mtod(m, int *)) 394 tp->t_flags |= TF_NODELAY; 395 else 396 tp->t_flags &= ~TF_NODELAY; 397 break; 398 399 case TCP_MAXSEG: 400 if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg) 401 tp->t_maxseg = i; 402 else 403 error = EINVAL; 404 break; 405 406 default: 407 error = ENOPROTOOPT; 408 break; 409 } 410 if (m) 411 (void) m_free(m); 412 break; 413 414 case PRCO_GETOPT: 415 *mp = m = m_get(M_WAIT, MT_SOOPTS); 416 m->m_len = sizeof(int); 417 418 switch (optname) { 419 case TCP_NODELAY: 420 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 421 break; 422 case TCP_MAXSEG: 423 *mtod(m, int *) = tp->t_maxseg; 424 break; 425 default: 426 error = ENOPROTOOPT; 427 break; 428 } 429 break; 430 } 431 splx(s); 432 return (error); 433 } 434 435 #ifndef TCP_SENDSPACE 436 #define TCP_SENDSPACE 1024*16; 437 #endif 438 int tcp_sendspace = TCP_SENDSPACE; 439 #ifndef TCP_RECVSPACE 440 #define TCP_RECVSPACE 1024*16; 441 #endif 442 int tcp_recvspace = TCP_RECVSPACE; 443 444 /* 445 * Attach TCP protocol to socket, allocating 446 * internet protocol control block, tcp control block, 447 * bufer space, and entering LISTEN state if to accept connections. 448 */ 449 int 450 tcp_attach(so) 451 struct socket *so; 452 { 453 register struct tcpcb *tp; 454 struct inpcb *inp; 455 int error; 456 457 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 458 error = soreserve(so, tcp_sendspace, tcp_recvspace); 459 if (error) 460 return (error); 461 } 462 error = in_pcballoc(so, &tcbtable); 463 if (error) 464 return (error); 465 inp = sotoinpcb(so); 466 tp = tcp_newtcpcb(inp); 467 if (tp == 0) { 468 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 469 470 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 471 in_pcbdetach(inp); 472 so->so_state |= nofd; 473 return (ENOBUFS); 474 } 475 tp->t_state = TCPS_CLOSED; 476 return (0); 477 } 478 479 /* 480 * Initiate (or continue) disconnect. 481 * If embryonic state, just send reset (once). 482 * If in ``let data drain'' option and linger null, just drop. 483 * Otherwise (hard), mark socket disconnecting and drop 484 * current input data; switch states based on user close, and 485 * send segment to peer (with FIN). 486 */ 487 struct tcpcb * 488 tcp_disconnect(tp) 489 register struct tcpcb *tp; 490 { 491 struct socket *so = tp->t_inpcb->inp_socket; 492 493 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 494 tp = tcp_close(tp); 495 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 496 tp = tcp_drop(tp, 0); 497 else { 498 soisdisconnecting(so); 499 sbflush(&so->so_rcv); 500 tp = tcp_usrclosed(tp); 501 if (tp) 502 (void) tcp_output(tp); 503 } 504 return (tp); 505 } 506 507 /* 508 * User issued close, and wish to trail through shutdown states: 509 * if never received SYN, just forget it. If got a SYN from peer, 510 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 511 * If already got a FIN from peer, then almost done; go to LAST_ACK 512 * state. In all other cases, have already sent FIN to peer (e.g. 513 * after PRU_SHUTDOWN), and just have to play tedious game waiting 514 * for peer to send FIN or not respond to keep-alives, etc. 515 * We can let the user exit from the close as soon as the FIN is acked. 516 */ 517 struct tcpcb * 518 tcp_usrclosed(tp) 519 register struct tcpcb *tp; 520 { 521 522 switch (tp->t_state) { 523 524 case TCPS_CLOSED: 525 case TCPS_LISTEN: 526 case TCPS_SYN_SENT: 527 tp->t_state = TCPS_CLOSED; 528 tp = tcp_close(tp); 529 break; 530 531 case TCPS_SYN_RECEIVED: 532 case TCPS_ESTABLISHED: 533 tp->t_state = TCPS_FIN_WAIT_1; 534 break; 535 536 case TCPS_CLOSE_WAIT: 537 tp->t_state = TCPS_LAST_ACK; 538 break; 539 } 540 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) { 541 soisdisconnected(tp->t_inpcb->inp_socket); 542 /* 543 * If we are in FIN_WAIT_2, we arrived here because the 544 * application did a shutdown of the send side. Like the 545 * case of a transition from FIN_WAIT_1 to FIN_WAIT_2 after 546 * a full close, we start a timer to make sure sockets are 547 * not left in FIN_WAIT_2 forever. 548 */ 549 if (tp->t_state == TCPS_FIN_WAIT_2) 550 tp->t_timer[TCPT_2MSL] = tcp_maxidle; 551 } 552 return (tp); 553 } 554 555 /* 556 * Sysctl for tcp variables. 557 */ 558 int 559 tcp_sysctl(name, namelen, oldp, oldlenp, newp, newlen) 560 int *name; 561 u_int namelen; 562 void *oldp; 563 size_t *oldlenp; 564 void *newp; 565 size_t newlen; 566 { 567 568 /* All sysctl names at this level are terminal. */ 569 if (namelen != 1) 570 return (ENOTDIR); 571 572 switch (name[0]) { 573 case TCPCTL_RFC1323: 574 return (sysctl_int(oldp, oldlenp, newp, newlen, 575 &tcp_do_rfc1323)); 576 case TCPCTL_SENDSPACE: 577 return (sysctl_int(oldp, oldlenp, newp, newlen, 578 &tcp_sendspace)); 579 case TCPCTL_RECVSPACE: 580 return (sysctl_int(oldp, oldlenp, newp, newlen, 581 &tcp_recvspace)); 582 case TCPCTL_MSSDFLT: 583 return (sysctl_int(oldp, oldlenp, newp, newlen, 584 &tcp_mssdflt)); 585 case TCPCTL_SYN_CACHE_LIMIT: 586 return (sysctl_int(oldp, oldlenp, newp, newlen, 587 &tcp_syn_cache_limit)); 588 case TCPCTL_SYN_BUCKET_LIMIT: 589 return (sysctl_int(oldp, oldlenp, newp, newlen, 590 &tcp_syn_bucket_limit)); 591 case TCPCTL_SYN_CACHE_INTER: 592 return (sysctl_int(oldp, oldlenp, newp, newlen, 593 &tcp_syn_cache_interval)); 594 default: 595 return (ENOPROTOOPT); 596 } 597 /* NOTREACHED */ 598 } 599
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