1 /* 2 * Copyright (c) 1982, 1986, 1988 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)tcp_usrreq.c 7.15 (Berkeley) 6/28/90 34 * $Id: tcp_usrreq.c,v 1.8 1994/01/10 23:27:45 mycroft Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/malloc.h> 40 #include <sys/mbuf.h> 41 #include <sys/socket.h> 42 #include <sys/socketvar.h> 43 #include <sys/protosw.h> 44 #include <sys/errno.h> 45 #include <sys/stat.h> 46 47 #include <net/if.h> 48 #include <net/route.h> 49 50 #include <netinet/in.h> 51 #include <netinet/in_systm.h> 52 #include <netinet/ip.h> 53 #include <netinet/in_pcb.h> 54 #include <netinet/ip_var.h> 55 #include <netinet/tcp.h> 56 #include <netinet/tcp_fsm.h> 57 #include <netinet/tcp_seq.h> 58 #include <netinet/tcp_timer.h> 59 #include <netinet/tcp_var.h> 60 #include <netinet/tcpip.h> 61 #include <netinet/tcp_debug.h> 62 63 /* 64 * TCP protocol interface to socket abstraction. 65 */ 66 extern char *tcpstates[]; 67 68 /* 69 * Process a TCP user request for TCP tb. If this is a send request 70 * then m is the mbuf chain of send data. If this is a timer expiration 71 * (called from the software clock routine), then timertype tells which timer. 72 */ 73 /*ARGSUSED*/ 74 int 75 tcp_usrreq(so, req, m, nam, control) 76 struct socket *so; 77 int req; 78 struct mbuf *m, *nam, *control; 79 { 80 register struct inpcb *inp; 81 register struct tcpcb *tp; 82 int s; 83 int error = 0; 84 int ostate; 85 86 if (req == PRU_CONTROL) 87 return (in_control(so, (int)m, (caddr_t)nam, 88 (struct ifnet *)control)); 89 if (control && control->m_len) { 90 m_freem(control); 91 if (m) 92 m_freem(m); 93 return (EINVAL); 94 } 95 96 s = splnet(); 97 inp = sotoinpcb(so); 98 /* 99 * When a TCP is attached to a socket, then there will be 100 * a (struct inpcb) pointed at by the socket, and this 101 * structure will point at a subsidary (struct tcpcb). 102 */ 103 if (inp == 0 && req != PRU_ATTACH) { 104 splx(s); 105 return (EINVAL); /* XXX */ 106 } 107 if (inp) { 108 tp = intotcpcb(inp); 109 /* WHAT IF TP IS 0? */ 110 #ifdef KPROF 111 tcp_acounts[tp->t_state][req]++; 112 #endif 113 ostate = tp->t_state; 114 } else 115 ostate = 0; 116 switch (req) { 117 118 /* 119 * TCP attaches to socket via PRU_ATTACH, reserving space, 120 * and an internet control block. 121 */ 122 case PRU_ATTACH: 123 if (inp) { 124 error = EISCONN; 125 break; 126 } 127 error = tcp_attach(so); 128 if (error) 129 break; 130 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 131 so->so_linger = TCP_LINGERTIME; 132 tp = sototcpcb(so); 133 break; 134 135 /* 136 * PRU_DETACH detaches the TCP protocol from the socket. 137 * If the protocol state is non-embryonic, then can't 138 * do this directly: have to initiate a PRU_DISCONNECT, 139 * which may finish later; embryonic TCB's can just 140 * be discarded here. 141 */ 142 case PRU_DETACH: 143 if (tp->t_state > TCPS_LISTEN) 144 tp = tcp_disconnect(tp); 145 else 146 tp = tcp_close(tp); 147 break; 148 149 /* 150 * Give the socket an address. 151 */ 152 case PRU_BIND: 153 error = in_pcbbind(inp, nam); 154 if (error) 155 break; 156 break; 157 158 /* 159 * Prepare to accept connections. 160 */ 161 case PRU_LISTEN: 162 if (inp->inp_lport == 0) 163 error = in_pcbbind(inp, (struct mbuf *)0); 164 if (error == 0) 165 tp->t_state = TCPS_LISTEN; 166 break; 167 168 /* 169 * Initiate connection to peer. 170 * Create a template for use in transmissions on this connection. 171 * Enter SYN_SENT state, and mark socket as connecting. 172 * Start keep-alive timer, and seed output sequence space. 173 * Send initial segment on connection. 174 */ 175 case PRU_CONNECT: 176 if (inp->inp_lport == 0) { 177 error = in_pcbbind(inp, (struct mbuf *)0); 178 if (error) 179 break; 180 } 181 error = in_pcbconnect(inp, nam); 182 if (error) 183 break; 184 tp->t_template = tcp_template(tp); 185 if (tp->t_template == 0) { 186 in_pcbdisconnect(inp); 187 error = ENOBUFS; 188 break; 189 } 190 soisconnecting(so); 191 tcpstat.tcps_connattempt++; 192 tp->t_state = TCPS_SYN_SENT; 193 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; 194 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 195 tcp_sendseqinit(tp); 196 error = tcp_output(tp); 197 break; 198 199 /* 200 * Create a TCP connection between two sockets. 201 */ 202 case PRU_CONNECT2: 203 error = EOPNOTSUPP; 204 break; 205 206 /* 207 * Initiate disconnect from peer. 208 * If connection never passed embryonic stage, just drop; 209 * else if don't need to let data drain, then can just drop anyways, 210 * else have to begin TCP shutdown process: mark socket disconnecting, 211 * drain unread data, state switch to reflect user close, and 212 * send segment (e.g. FIN) to peer. Socket will be really disconnected 213 * when peer sends FIN and acks ours. 214 * 215 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 216 */ 217 case PRU_DISCONNECT: 218 tp = tcp_disconnect(tp); 219 break; 220 221 /* 222 * Accept a connection. Essentially all the work is 223 * done at higher levels; just return the address 224 * of the peer, storing through addr. 225 */ 226 case PRU_ACCEPT: 227 in_setpeeraddr(inp, nam); 228 break; 229 230 /* 231 * Mark the connection as being incapable of further output. 232 */ 233 case PRU_SHUTDOWN: 234 socantsendmore(so); 235 tp = tcp_usrclosed(tp); 236 if (tp) 237 error = tcp_output(tp); 238 break; 239 240 /* 241 * After a receive, possibly send window update to peer. 242 */ 243 case PRU_RCVD: 244 (void) tcp_output(tp); 245 break; 246 247 /* 248 * Do a send by putting data in output queue and updating urgent 249 * marker if URG set. Possibly send more data. 250 */ 251 case PRU_SEND: 252 sbappend(&so->so_snd, m); 253 error = tcp_output(tp); 254 break; 255 256 /* 257 * Abort the TCP. 258 */ 259 case PRU_ABORT: 260 tp = tcp_drop(tp, ECONNABORTED); 261 break; 262 263 case PRU_SENSE: 264 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 265 (void) splx(s); 266 return (0); 267 268 case PRU_RCVOOB: 269 if ((so->so_oobmark == 0 && 270 (so->so_state & SS_RCVATMARK) == 0) || 271 so->so_options & SO_OOBINLINE || 272 tp->t_oobflags & TCPOOB_HADDATA) { 273 error = EINVAL; 274 break; 275 } 276 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 277 error = EWOULDBLOCK; 278 break; 279 } 280 m->m_len = 1; 281 *mtod(m, caddr_t) = tp->t_iobc; 282 if (((int)nam & MSG_PEEK) == 0) 283 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 284 break; 285 286 case PRU_SENDOOB: 287 if (sbspace(&so->so_snd) < -512) { 288 m_freem(m); 289 error = ENOBUFS; 290 break; 291 } 292 /* 293 * According to RFC961 (Assigned Protocols), 294 * the urgent pointer points to the last octet 295 * of urgent data. We continue, however, 296 * to consider it to indicate the first octet 297 * of data past the urgent section. 298 * Otherwise, snd_up should be one lower. 299 */ 300 sbappend(&so->so_snd, m); 301 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 302 tp->t_force = 1; 303 error = tcp_output(tp); 304 tp->t_force = 0; 305 break; 306 307 case PRU_SOCKADDR: 308 in_setsockaddr(inp, nam); 309 break; 310 311 case PRU_PEERADDR: 312 in_setpeeraddr(inp, nam); 313 break; 314 315 /* 316 * TCP slow timer went off; going through this 317 * routine for tracing's sake. 318 */ 319 case PRU_SLOWTIMO: 320 tp = tcp_timers(tp, (int)nam); 321 req |= (int)nam << 8; /* for debug's sake */ 322 break; 323 324 default: 325 panic("tcp_usrreq"); 326 } 327 if (tp && (so->so_options & SO_DEBUG)) 328 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 329 splx(s); 330 return (error); 331 } 332 333 int 334 tcp_ctloutput(op, so, level, optname, mp) 335 int op; 336 struct socket *so; 337 int level, optname; 338 struct mbuf **mp; 339 { 340 int error = 0; 341 struct inpcb *inp = sotoinpcb(so); 342 register struct tcpcb *tp = intotcpcb(inp); 343 register struct mbuf *m; 344 345 if (level != IPPROTO_TCP) 346 return (ip_ctloutput(op, so, level, optname, mp)); 347 348 switch (op) { 349 350 case PRCO_SETOPT: 351 m = *mp; 352 switch (optname) { 353 354 case TCP_NODELAY: 355 if (m == NULL || m->m_len < sizeof (int)) 356 error = EINVAL; 357 else if (*mtod(m, int *)) 358 tp->t_flags |= TF_NODELAY; 359 else 360 tp->t_flags &= ~TF_NODELAY; 361 break; 362 363 case TCP_MAXSEG: /* not yet */ 364 default: 365 error = EINVAL; 366 break; 367 } 368 if (m) 369 (void) m_free(m); 370 break; 371 372 case PRCO_GETOPT: 373 *mp = m = m_get(M_WAIT, MT_SOOPTS); 374 m->m_len = sizeof(int); 375 376 switch (optname) { 377 case TCP_NODELAY: 378 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 379 break; 380 case TCP_MAXSEG: 381 *mtod(m, int *) = tp->t_maxseg; 382 break; 383 default: 384 error = EINVAL; 385 break; 386 } 387 break; 388 } 389 return (error); 390 } 391 392 u_long tcp_sendspace = 1024*8; 393 u_long tcp_recvspace = 1024*8; 394 395 /* 396 * Attach TCP protocol to socket, allocating 397 * internet protocol control block, tcp control block, 398 * bufer space, and entering LISTEN state if to accept connections. 399 */ 400 int 401 tcp_attach(so) 402 struct socket *so; 403 { 404 register struct tcpcb *tp; 405 struct inpcb *inp; 406 int error; 407 408 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 409 error = soreserve(so, tcp_sendspace, tcp_recvspace); 410 if (error) 411 return (error); 412 } 413 error = in_pcballoc(so, &tcb); 414 if (error) 415 return (error); 416 inp = sotoinpcb(so); 417 tp = tcp_newtcpcb(inp); 418 if (tp == 0) { 419 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 420 421 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 422 in_pcbdetach(inp); 423 so->so_state |= nofd; 424 return (ENOBUFS); 425 } 426 tp->t_state = TCPS_CLOSED; 427 return (0); 428 } 429 430 /* 431 * Initiate (or continue) disconnect. 432 * If embryonic state, just send reset (once). 433 * If in ``let data drain'' option and linger null, just drop. 434 * Otherwise (hard), mark socket disconnecting and drop 435 * current input data; switch states based on user close, and 436 * send segment to peer (with FIN). 437 */ 438 struct tcpcb * 439 tcp_disconnect(tp) 440 register struct tcpcb *tp; 441 { 442 struct socket *so = tp->t_inpcb->inp_socket; 443 444 if (tp->t_state < TCPS_ESTABLISHED) 445 tp = tcp_close(tp); 446 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 447 tp = tcp_drop(tp, 0); 448 else { 449 soisdisconnecting(so); 450 sbflush(&so->so_rcv); 451 tp = tcp_usrclosed(tp); 452 if (tp) 453 (void) tcp_output(tp); 454 } 455 return (tp); 456 } 457 458 /* 459 * User issued close, and wish to trail through shutdown states: 460 * if never received SYN, just forget it. If got a SYN from peer, 461 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 462 * If already got a FIN from peer, then almost done; go to LAST_ACK 463 * state. In all other cases, have already sent FIN to peer (e.g. 464 * after PRU_SHUTDOWN), and just have to play tedious game waiting 465 * for peer to send FIN or not respond to keep-alives, etc. 466 * We can let the user exit from the close as soon as the FIN is acked. 467 */ 468 struct tcpcb * 469 tcp_usrclosed(tp) 470 register struct tcpcb *tp; 471 { 472 473 switch (tp->t_state) { 474 475 case TCPS_CLOSED: 476 case TCPS_LISTEN: 477 case TCPS_SYN_SENT: 478 tp->t_state = TCPS_CLOSED; 479 tp = tcp_close(tp); 480 break; 481 482 case TCPS_SYN_RECEIVED: 483 case TCPS_ESTABLISHED: 484 tp->t_state = TCPS_FIN_WAIT_1; 485 break; 486 487 case TCPS_CLOSE_WAIT: 488 tp->t_state = TCPS_LAST_ACK; 489 break; 490 } 491 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 492 soisdisconnected(tp->t_inpcb->inp_socket); 493 return (tp); 494 } 495