1 /* $NetBSD: tcp_usrreq.c,v 1.10 1994/06/29 06:38:52 cgd 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/malloc.h> 41 #include <sys/mbuf.h> 42 #include <sys/socket.h> 43 #include <sys/socketvar.h> 44 #include <sys/protosw.h> 45 #include <sys/errno.h> 46 #include <sys/stat.h> 47 48 #include <net/if.h> 49 #include <net/route.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_systm.h> 53 #include <netinet/ip.h> 54 #include <netinet/in_pcb.h> 55 #include <netinet/ip_var.h> 56 #include <netinet/tcp.h> 57 #include <netinet/tcp_fsm.h> 58 #include <netinet/tcp_seq.h> 59 #include <netinet/tcp_timer.h> 60 #include <netinet/tcp_var.h> 61 #include <netinet/tcpip.h> 62 #include <netinet/tcp_debug.h> 63 64 /* 65 * TCP protocol interface to socket abstraction. 66 */ 67 extern char *tcpstates[]; 68 69 /* 70 * Process a TCP user request for TCP tb. If this is a send request 71 * then m is the mbuf chain of send data. If this is a timer expiration 72 * (called from the software clock routine), then timertype tells which timer. 73 */ 74 /*ARGSUSED*/ 75 int 76 tcp_usrreq(so, req, m, nam, control) 77 struct socket *so; 78 int req; 79 struct mbuf *m, *nam, *control; 80 { 81 register struct inpcb *inp; 82 register struct tcpcb *tp; 83 int s; 84 int error = 0; 85 int ostate; 86 87 if (req == PRU_CONTROL) 88 return (in_control(so, (int)m, (caddr_t)nam, 89 (struct ifnet *)control)); 90 if (control && control->m_len) { 91 m_freem(control); 92 if (m) 93 m_freem(m); 94 return (EINVAL); 95 } 96 97 s = splnet(); 98 inp = sotoinpcb(so); 99 /* 100 * When a TCP is attached to a socket, then there will be 101 * a (struct inpcb) pointed at by the socket, and this 102 * structure will point at a subsidary (struct tcpcb). 103 */ 104 if (inp == 0 && req != PRU_ATTACH) { 105 splx(s); 106 return (EINVAL); /* XXX */ 107 } 108 if (inp) { 109 tp = intotcpcb(inp); 110 /* WHAT IF TP IS 0? */ 111 #ifdef KPROF 112 tcp_acounts[tp->t_state][req]++; 113 #endif 114 ostate = tp->t_state; 115 } else 116 ostate = 0; 117 switch (req) { 118 119 /* 120 * TCP attaches to socket via PRU_ATTACH, reserving space, 121 * and an internet control block. 122 */ 123 case PRU_ATTACH: 124 if (inp) { 125 error = EISCONN; 126 break; 127 } 128 error = tcp_attach(so); 129 if (error) 130 break; 131 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 132 so->so_linger = TCP_LINGERTIME; 133 tp = sototcpcb(so); 134 break; 135 136 /* 137 * PRU_DETACH detaches the TCP protocol from the socket. 138 * If the protocol state is non-embryonic, then can't 139 * do this directly: have to initiate a PRU_DISCONNECT, 140 * which may finish later; embryonic TCB's can just 141 * be discarded here. 142 */ 143 case PRU_DETACH: 144 if (tp->t_state > TCPS_LISTEN) 145 tp = tcp_disconnect(tp); 146 else 147 tp = tcp_close(tp); 148 break; 149 150 /* 151 * Give the socket an address. 152 */ 153 case PRU_BIND: 154 error = in_pcbbind(inp, nam); 155 if (error) 156 break; 157 break; 158 159 /* 160 * Prepare to accept connections. 161 */ 162 case PRU_LISTEN: 163 if (inp->inp_lport == 0) 164 error = in_pcbbind(inp, (struct mbuf *)0); 165 if (error == 0) 166 tp->t_state = TCPS_LISTEN; 167 break; 168 169 /* 170 * Initiate connection to peer. 171 * Create a template for use in transmissions on this connection. 172 * Enter SYN_SENT state, and mark socket as connecting. 173 * Start keep-alive timer, and seed output sequence space. 174 * Send initial segment on connection. 175 */ 176 case PRU_CONNECT: 177 if (inp->inp_lport == 0) { 178 error = in_pcbbind(inp, (struct mbuf *)0); 179 if (error) 180 break; 181 } 182 error = in_pcbconnect(inp, nam); 183 if (error) 184 break; 185 tp->t_template = tcp_template(tp); 186 if (tp->t_template == 0) { 187 in_pcbdisconnect(inp); 188 error = ENOBUFS; 189 break; 190 } 191 /* Compute window scaling to request. */ 192 while (tp->request_r_scale < TCP_MAX_WINSHIFT && 193 (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat) 194 tp->request_r_scale++; 195 soisconnecting(so); 196 tcpstat.tcps_connattempt++; 197 tp->t_state = TCPS_SYN_SENT; 198 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; 199 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 200 tcp_sendseqinit(tp); 201 error = tcp_output(tp); 202 break; 203 204 /* 205 * Create a TCP connection between two sockets. 206 */ 207 case PRU_CONNECT2: 208 error = EOPNOTSUPP; 209 break; 210 211 /* 212 * Initiate disconnect from peer. 213 * If connection never passed embryonic stage, just drop; 214 * else if don't need to let data drain, then can just drop anyways, 215 * else have to begin TCP shutdown process: mark socket disconnecting, 216 * drain unread data, state switch to reflect user close, and 217 * send segment (e.g. FIN) to peer. Socket will be really disconnected 218 * when peer sends FIN and acks ours. 219 * 220 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 221 */ 222 case PRU_DISCONNECT: 223 tp = tcp_disconnect(tp); 224 break; 225 226 /* 227 * Accept a connection. Essentially all the work is 228 * done at higher levels; just return the address 229 * of the peer, storing through addr. 230 */ 231 case PRU_ACCEPT: 232 in_setpeeraddr(inp, nam); 233 break; 234 235 /* 236 * Mark the connection as being incapable of further output. 237 */ 238 case PRU_SHUTDOWN: 239 socantsendmore(so); 240 tp = tcp_usrclosed(tp); 241 if (tp) 242 error = tcp_output(tp); 243 break; 244 245 /* 246 * After a receive, possibly send window update to peer. 247 */ 248 case PRU_RCVD: 249 (void) tcp_output(tp); 250 break; 251 252 /* 253 * Do a send by putting data in output queue and updating urgent 254 * marker if URG set. Possibly send more data. 255 */ 256 case PRU_SEND: 257 sbappend(&so->so_snd, m); 258 error = tcp_output(tp); 259 break; 260 261 /* 262 * Abort the TCP. 263 */ 264 case PRU_ABORT: 265 tp = tcp_drop(tp, ECONNABORTED); 266 break; 267 268 case PRU_SENSE: 269 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 270 (void) splx(s); 271 return (0); 272 273 case PRU_RCVOOB: 274 if ((so->so_oobmark == 0 && 275 (so->so_state & SS_RCVATMARK) == 0) || 276 so->so_options & SO_OOBINLINE || 277 tp->t_oobflags & TCPOOB_HADDATA) { 278 error = EINVAL; 279 break; 280 } 281 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 282 error = EWOULDBLOCK; 283 break; 284 } 285 m->m_len = 1; 286 *mtod(m, caddr_t) = tp->t_iobc; 287 if (((int)nam & MSG_PEEK) == 0) 288 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 289 break; 290 291 case PRU_SENDOOB: 292 if (sbspace(&so->so_snd) < -512) { 293 m_freem(m); 294 error = ENOBUFS; 295 break; 296 } 297 /* 298 * According to RFC961 (Assigned Protocols), 299 * the urgent pointer points to the last octet 300 * of urgent data. We continue, however, 301 * to consider it to indicate the first octet 302 * of data past the urgent section. 303 * Otherwise, snd_up should be one lower. 304 */ 305 sbappend(&so->so_snd, m); 306 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 307 tp->t_force = 1; 308 error = tcp_output(tp); 309 tp->t_force = 0; 310 break; 311 312 case PRU_SOCKADDR: 313 in_setsockaddr(inp, nam); 314 break; 315 316 case PRU_PEERADDR: 317 in_setpeeraddr(inp, nam); 318 break; 319 320 /* 321 * TCP slow timer went off; going through this 322 * routine for tracing's sake. 323 */ 324 case PRU_SLOWTIMO: 325 tp = tcp_timers(tp, (int)nam); 326 req |= (int)nam << 8; /* for debug's sake */ 327 break; 328 329 default: 330 panic("tcp_usrreq"); 331 } 332 if (tp && (so->so_options & SO_DEBUG)) 333 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 334 splx(s); 335 return (error); 336 } 337 338 int 339 tcp_ctloutput(op, so, level, optname, mp) 340 int op; 341 struct socket *so; 342 int level, optname; 343 struct mbuf **mp; 344 { 345 int error = 0, s; 346 struct inpcb *inp; 347 register struct tcpcb *tp; 348 register struct mbuf *m; 349 register int i; 350 351 s = splnet(); 352 inp = sotoinpcb(so); 353 if (inp == NULL) { 354 splx(s); 355 if (op == PRCO_SETOPT && *mp) 356 (void) m_free(*mp); 357 return (ECONNRESET); 358 } 359 if (level != IPPROTO_TCP) { 360 error = ip_ctloutput(op, so, level, optname, mp); 361 splx(s); 362 return (error); 363 } 364 tp = intotcpcb(inp); 365 366 switch (op) { 367 368 case PRCO_SETOPT: 369 m = *mp; 370 switch (optname) { 371 372 case TCP_NODELAY: 373 if (m == NULL || m->m_len < sizeof (int)) 374 error = EINVAL; 375 else if (*mtod(m, int *)) 376 tp->t_flags |= TF_NODELAY; 377 else 378 tp->t_flags &= ~TF_NODELAY; 379 break; 380 381 case TCP_MAXSEG: 382 if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg) 383 tp->t_maxseg = i; 384 else 385 error = EINVAL; 386 break; 387 388 default: 389 error = ENOPROTOOPT; 390 break; 391 } 392 if (m) 393 (void) m_free(m); 394 break; 395 396 case PRCO_GETOPT: 397 *mp = m = m_get(M_WAIT, MT_SOOPTS); 398 m->m_len = sizeof(int); 399 400 switch (optname) { 401 case TCP_NODELAY: 402 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 403 break; 404 case TCP_MAXSEG: 405 *mtod(m, int *) = tp->t_maxseg; 406 break; 407 default: 408 error = ENOPROTOOPT; 409 break; 410 } 411 break; 412 } 413 splx(s); 414 return (error); 415 } 416 417 u_long tcp_sendspace = 1024*8; 418 u_long tcp_recvspace = 1024*8; 419 420 /* 421 * Attach TCP protocol to socket, allocating 422 * internet protocol control block, tcp control block, 423 * bufer space, and entering LISTEN state if to accept connections. 424 */ 425 int 426 tcp_attach(so) 427 struct socket *so; 428 { 429 register struct tcpcb *tp; 430 struct inpcb *inp; 431 int error; 432 433 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 434 error = soreserve(so, tcp_sendspace, tcp_recvspace); 435 if (error) 436 return (error); 437 } 438 error = in_pcballoc(so, &tcb); 439 if (error) 440 return (error); 441 inp = sotoinpcb(so); 442 tp = tcp_newtcpcb(inp); 443 if (tp == 0) { 444 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 445 446 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 447 in_pcbdetach(inp); 448 so->so_state |= nofd; 449 return (ENOBUFS); 450 } 451 tp->t_state = TCPS_CLOSED; 452 return (0); 453 } 454 455 /* 456 * Initiate (or continue) disconnect. 457 * If embryonic state, just send reset (once). 458 * If in ``let data drain'' option and linger null, just drop. 459 * Otherwise (hard), mark socket disconnecting and drop 460 * current input data; switch states based on user close, and 461 * send segment to peer (with FIN). 462 */ 463 struct tcpcb * 464 tcp_disconnect(tp) 465 register struct tcpcb *tp; 466 { 467 struct socket *so = tp->t_inpcb->inp_socket; 468 469 if (tp->t_state < TCPS_ESTABLISHED) 470 tp = tcp_close(tp); 471 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 472 tp = tcp_drop(tp, 0); 473 else { 474 soisdisconnecting(so); 475 sbflush(&so->so_rcv); 476 tp = tcp_usrclosed(tp); 477 if (tp) 478 (void) tcp_output(tp); 479 } 480 return (tp); 481 } 482 483 /* 484 * User issued close, and wish to trail through shutdown states: 485 * if never received SYN, just forget it. If got a SYN from peer, 486 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 487 * If already got a FIN from peer, then almost done; go to LAST_ACK 488 * state. In all other cases, have already sent FIN to peer (e.g. 489 * after PRU_SHUTDOWN), and just have to play tedious game waiting 490 * for peer to send FIN or not respond to keep-alives, etc. 491 * We can let the user exit from the close as soon as the FIN is acked. 492 */ 493 struct tcpcb * 494 tcp_usrclosed(tp) 495 register struct tcpcb *tp; 496 { 497 498 switch (tp->t_state) { 499 500 case TCPS_CLOSED: 501 case TCPS_LISTEN: 502 case TCPS_SYN_SENT: 503 tp->t_state = TCPS_CLOSED; 504 tp = tcp_close(tp); 505 break; 506 507 case TCPS_SYN_RECEIVED: 508 case TCPS_ESTABLISHED: 509 tp->t_state = TCPS_FIN_WAIT_1; 510 break; 511 512 case TCPS_CLOSE_WAIT: 513 tp->t_state = TCPS_LAST_ACK; 514 break; 515 } 516 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 517 soisdisconnected(tp->t_inpcb->inp_socket); 518 return (tp); 519 } 520