1 /* $NetBSD: tcp_usrreq.c,v 1.14 1995/04/13 06:36:53 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/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 49 #include <net/if.h> 50 #include <net/route.h> 51 52 #include <netinet/in.h> 53 #include <netinet/in_systm.h> 54 #include <netinet/in_var.h> 55 #include <netinet/ip.h> 56 #include <netinet/in_pcb.h> 57 #include <netinet/ip_var.h> 58 #include <netinet/tcp.h> 59 #include <netinet/tcp_fsm.h> 60 #include <netinet/tcp_seq.h> 61 #include <netinet/tcp_timer.h> 62 #include <netinet/tcp_var.h> 63 #include <netinet/tcpip.h> 64 #include <netinet/tcp_debug.h> 65 66 /* 67 * TCP protocol interface to socket abstraction. 68 */ 69 extern char *tcpstates[]; 70 71 /* 72 * Process a TCP user request for TCP tb. If this is a send request 73 * then m is the mbuf chain of send data. If this is a timer expiration 74 * (called from the software clock routine), then timertype tells which timer. 75 */ 76 /*ARGSUSED*/ 77 int 78 tcp_usrreq(so, req, m, nam, control) 79 struct socket *so; 80 int req; 81 struct mbuf *m, *nam, *control; 82 { 83 register struct inpcb *inp; 84 register struct tcpcb *tp; 85 int s; 86 int error = 0; 87 int ostate; 88 89 if (req == PRU_CONTROL) 90 return (in_control(so, (long)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 * hz; 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 error = in_pcbbind(inp, nam); 157 if (error) 158 break; 159 break; 160 161 /* 162 * Prepare to accept connections. 163 */ 164 case PRU_LISTEN: 165 if (inp->inp_lport == 0) 166 error = in_pcbbind(inp, (struct mbuf *)0); 167 if (error == 0) 168 tp->t_state = TCPS_LISTEN; 169 break; 170 171 /* 172 * Initiate connection to peer. 173 * Create a template for use in transmissions on this connection. 174 * Enter SYN_SENT state, and mark socket as connecting. 175 * Start keep-alive timer, and seed output sequence space. 176 * Send initial segment on connection. 177 */ 178 case PRU_CONNECT: 179 if (inp->inp_lport == 0) { 180 error = in_pcbbind(inp, (struct mbuf *)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 sbappend(&so->so_snd, m); 260 error = tcp_output(tp); 261 break; 262 263 /* 264 * Abort the TCP. 265 */ 266 case PRU_ABORT: 267 tp = tcp_drop(tp, ECONNABORTED); 268 break; 269 270 case PRU_SENSE: 271 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 272 (void) splx(s); 273 return (0); 274 275 case PRU_RCVOOB: 276 if ((so->so_oobmark == 0 && 277 (so->so_state & SS_RCVATMARK) == 0) || 278 so->so_options & SO_OOBINLINE || 279 tp->t_oobflags & TCPOOB_HADDATA) { 280 error = EINVAL; 281 break; 282 } 283 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 284 error = EWOULDBLOCK; 285 break; 286 } 287 m->m_len = 1; 288 *mtod(m, caddr_t) = tp->t_iobc; 289 if (((long)nam & MSG_PEEK) == 0) 290 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 291 break; 292 293 case PRU_SENDOOB: 294 if (sbspace(&so->so_snd) < -512) { 295 m_freem(m); 296 error = ENOBUFS; 297 break; 298 } 299 /* 300 * According to RFC961 (Assigned Protocols), 301 * the urgent pointer points to the last octet 302 * of urgent data. We continue, however, 303 * to consider it to indicate the first octet 304 * of data past the urgent section. 305 * Otherwise, snd_up should be one lower. 306 */ 307 sbappend(&so->so_snd, m); 308 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 309 tp->t_force = 1; 310 error = tcp_output(tp); 311 tp->t_force = 0; 312 break; 313 314 case PRU_SOCKADDR: 315 in_setsockaddr(inp, nam); 316 break; 317 318 case PRU_PEERADDR: 319 in_setpeeraddr(inp, nam); 320 break; 321 322 /* 323 * TCP slow timer went off; going through this 324 * routine for tracing's sake. 325 */ 326 case PRU_SLOWTIMO: 327 tp = tcp_timers(tp, (long)nam); 328 req |= (long)nam << 8; /* for debug's sake */ 329 break; 330 331 default: 332 panic("tcp_usrreq"); 333 } 334 if (tp && (so->so_options & SO_DEBUG)) 335 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 336 splx(s); 337 return (error); 338 } 339 340 int 341 tcp_ctloutput(op, so, level, optname, mp) 342 int op; 343 struct socket *so; 344 int level, optname; 345 struct mbuf **mp; 346 { 347 int error = 0, s; 348 struct inpcb *inp; 349 register struct tcpcb *tp; 350 register struct mbuf *m; 351 register int i; 352 353 s = splnet(); 354 inp = sotoinpcb(so); 355 if (inp == NULL) { 356 splx(s); 357 if (op == PRCO_SETOPT && *mp) 358 (void) m_free(*mp); 359 return (ECONNRESET); 360 } 361 if (level != IPPROTO_TCP) { 362 error = ip_ctloutput(op, so, level, optname, mp); 363 splx(s); 364 return (error); 365 } 366 tp = intotcpcb(inp); 367 368 switch (op) { 369 370 case PRCO_SETOPT: 371 m = *mp; 372 switch (optname) { 373 374 case TCP_NODELAY: 375 if (m == NULL || m->m_len < sizeof (int)) 376 error = EINVAL; 377 else if (*mtod(m, int *)) 378 tp->t_flags |= TF_NODELAY; 379 else 380 tp->t_flags &= ~TF_NODELAY; 381 break; 382 383 case TCP_MAXSEG: 384 if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg) 385 tp->t_maxseg = i; 386 else 387 error = EINVAL; 388 break; 389 390 default: 391 error = ENOPROTOOPT; 392 break; 393 } 394 if (m) 395 (void) m_free(m); 396 break; 397 398 case PRCO_GETOPT: 399 *mp = m = m_get(M_WAIT, MT_SOOPTS); 400 m->m_len = sizeof(int); 401 402 switch (optname) { 403 case TCP_NODELAY: 404 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 405 break; 406 case TCP_MAXSEG: 407 *mtod(m, int *) = tp->t_maxseg; 408 break; 409 default: 410 error = ENOPROTOOPT; 411 break; 412 } 413 break; 414 } 415 splx(s); 416 return (error); 417 } 418 419 #ifndef TCP_SENDSPACE 420 #define TCP_SENDSPACE 1024*16; 421 #endif 422 u_long tcp_sendspace = TCP_SENDSPACE; 423 #ifndef TCP_RECVSPACE 424 #define TCP_RECVSPACE 1024*16; 425 #endif 426 u_long tcp_recvspace = TCP_RECVSPACE; 427 428 /* 429 * Attach TCP protocol to socket, allocating 430 * internet protocol control block, tcp control block, 431 * bufer space, and entering LISTEN state if to accept connections. 432 */ 433 int 434 tcp_attach(so) 435 struct socket *so; 436 { 437 register struct tcpcb *tp; 438 struct inpcb *inp; 439 int error; 440 441 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 442 error = soreserve(so, tcp_sendspace, tcp_recvspace); 443 if (error) 444 return (error); 445 } 446 error = in_pcballoc(so, &tcb); 447 if (error) 448 return (error); 449 inp = sotoinpcb(so); 450 tp = tcp_newtcpcb(inp); 451 if (tp == 0) { 452 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 453 454 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 455 in_pcbdetach(inp); 456 so->so_state |= nofd; 457 return (ENOBUFS); 458 } 459 tp->t_state = TCPS_CLOSED; 460 return (0); 461 } 462 463 /* 464 * Initiate (or continue) disconnect. 465 * If embryonic state, just send reset (once). 466 * If in ``let data drain'' option and linger null, just drop. 467 * Otherwise (hard), mark socket disconnecting and drop 468 * current input data; switch states based on user close, and 469 * send segment to peer (with FIN). 470 */ 471 struct tcpcb * 472 tcp_disconnect(tp) 473 register struct tcpcb *tp; 474 { 475 struct socket *so = tp->t_inpcb->inp_socket; 476 477 if (TCPS_HAVEESTABLISHED(tp->t_state) == 0) 478 tp = tcp_close(tp); 479 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 480 tp = tcp_drop(tp, 0); 481 else { 482 soisdisconnecting(so); 483 sbflush(&so->so_rcv); 484 tp = tcp_usrclosed(tp); 485 if (tp) 486 (void) tcp_output(tp); 487 } 488 return (tp); 489 } 490 491 /* 492 * User issued close, and wish to trail through shutdown states: 493 * if never received SYN, just forget it. If got a SYN from peer, 494 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 495 * If already got a FIN from peer, then almost done; go to LAST_ACK 496 * state. In all other cases, have already sent FIN to peer (e.g. 497 * after PRU_SHUTDOWN), and just have to play tedious game waiting 498 * for peer to send FIN or not respond to keep-alives, etc. 499 * We can let the user exit from the close as soon as the FIN is acked. 500 */ 501 struct tcpcb * 502 tcp_usrclosed(tp) 503 register struct tcpcb *tp; 504 { 505 506 switch (tp->t_state) { 507 508 case TCPS_CLOSED: 509 case TCPS_LISTEN: 510 case TCPS_SYN_SENT: 511 tp->t_state = TCPS_CLOSED; 512 tp = tcp_close(tp); 513 break; 514 515 case TCPS_SYN_RECEIVED: 516 case TCPS_ESTABLISHED: 517 tp->t_state = TCPS_FIN_WAIT_1; 518 break; 519 520 case TCPS_CLOSE_WAIT: 521 tp->t_state = TCPS_LAST_ACK; 522 break; 523 } 524 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 525 soisdisconnected(tp->t_inpcb->inp_socket); 526 return (tp); 527 } 528