1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 * 17 * @(#)tcp_usrreq.c 7.7.1.3 (Berkeley) 02/15/89 18 */ 19 20 #include "param.h" 21 #include "systm.h" 22 #include "mbuf.h" 23 #include "socket.h" 24 #include "socketvar.h" 25 #include "protosw.h" 26 #include "errno.h" 27 #include "stat.h" 28 29 #include "../net/if.h" 30 #include "../net/route.h" 31 32 #include "in.h" 33 #include "in_pcb.h" 34 #include "in_systm.h" 35 #include "ip.h" 36 #include "ip_var.h" 37 #include "tcp.h" 38 #include "tcp_fsm.h" 39 #include "tcp_seq.h" 40 #include "tcp_timer.h" 41 #include "tcp_var.h" 42 #include "tcpip.h" 43 #include "tcp_debug.h" 44 45 /* 46 * TCP protocol interface to socket abstraction. 47 */ 48 extern char *tcpstates[]; 49 struct tcpcb *tcp_newtcpcb(); 50 51 /* 52 * Process a TCP user request for TCP tb. If this is a send request 53 * then m is the mbuf chain of send data. If this is a timer expiration 54 * (called from the software clock routine), then timertype tells which timer. 55 */ 56 /*ARGSUSED*/ 57 tcp_usrreq(so, req, m, nam, rights) 58 struct socket *so; 59 int req; 60 struct mbuf *m, *nam, *rights; 61 { 62 register struct inpcb *inp; 63 register struct tcpcb *tp; 64 int s; 65 int error = 0; 66 int ostate; 67 68 #if BSD>=43 69 if (req == PRU_CONTROL) 70 return (in_control(so, (int)m, (caddr_t)nam, 71 (struct ifnet *)rights)); 72 #else 73 if (req == PRU_CONTROL) 74 return(EOPNOTSUPP); 75 #endif 76 if (rights && rights->m_len) 77 return (EINVAL); 78 79 s = splnet(); 80 inp = sotoinpcb(so); 81 /* 82 * When a TCP is attached to a socket, then there will be 83 * a (struct inpcb) pointed at by the socket, and this 84 * structure will point at a subsidary (struct tcpcb). 85 */ 86 if (inp == 0 && req != PRU_ATTACH) { 87 splx(s); 88 return (EINVAL); /* XXX */ 89 } 90 if (inp) { 91 tp = intotcpcb(inp); 92 /* WHAT IF TP IS 0? */ 93 #ifdef KPROF 94 tcp_acounts[tp->t_state][req]++; 95 #endif 96 ostate = tp->t_state; 97 } else 98 ostate = 0; 99 switch (req) { 100 101 /* 102 * TCP attaches to socket via PRU_ATTACH, reserving space, 103 * and an internet control block. 104 */ 105 case PRU_ATTACH: 106 if (inp) { 107 error = EISCONN; 108 break; 109 } 110 error = tcp_attach(so); 111 if (error) 112 break; 113 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 114 so->so_linger = TCP_LINGERTIME; 115 tp = sototcpcb(so); 116 break; 117 118 /* 119 * PRU_DETACH detaches the TCP protocol from the socket. 120 * If the protocol state is non-embryonic, then can't 121 * do this directly: have to initiate a PRU_DISCONNECT, 122 * which may finish later; embryonic TCB's can just 123 * be discarded here. 124 */ 125 case PRU_DETACH: 126 if (tp->t_state > TCPS_LISTEN) 127 tp = tcp_disconnect(tp); 128 else 129 tp = tcp_close(tp); 130 break; 131 132 /* 133 * Give the socket an address. 134 */ 135 case PRU_BIND: 136 error = in_pcbbind(inp, nam); 137 if (error) 138 break; 139 break; 140 141 /* 142 * Prepare to accept connections. 143 */ 144 case PRU_LISTEN: 145 if (inp->inp_lport == 0) 146 error = in_pcbbind(inp, (struct mbuf *)0); 147 if (error == 0) 148 tp->t_state = TCPS_LISTEN; 149 break; 150 151 /* 152 * Initiate connection to peer. 153 * Create a template for use in transmissions on this connection. 154 * Enter SYN_SENT state, and mark socket as connecting. 155 * Start keep-alive timer, and seed output sequence space. 156 * Send initial segment on connection. 157 */ 158 case PRU_CONNECT: 159 if (inp->inp_lport == 0) { 160 error = in_pcbbind(inp, (struct mbuf *)0); 161 if (error) 162 break; 163 } 164 error = in_pcbconnect(inp, nam); 165 if (error) 166 break; 167 tp->t_template = tcp_template(tp); 168 if (tp->t_template == 0) { 169 in_pcbdisconnect(inp); 170 error = ENOBUFS; 171 break; 172 } 173 soisconnecting(so); 174 tcpstat.tcps_connattempt++; 175 tp->t_state = TCPS_SYN_SENT; 176 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT; 177 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 178 tcp_sendseqinit(tp); 179 error = tcp_output(tp); 180 break; 181 182 /* 183 * Create a TCP connection between two sockets. 184 */ 185 case PRU_CONNECT2: 186 error = EOPNOTSUPP; 187 break; 188 189 /* 190 * Initiate disconnect from peer. 191 * If connection never passed embryonic stage, just drop; 192 * else if don't need to let data drain, then can just drop anyways, 193 * else have to begin TCP shutdown process: mark socket disconnecting, 194 * drain unread data, state switch to reflect user close, and 195 * send segment (e.g. FIN) to peer. Socket will be really disconnected 196 * when peer sends FIN and acks ours. 197 * 198 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 199 */ 200 case PRU_DISCONNECT: 201 tp = tcp_disconnect(tp); 202 break; 203 204 /* 205 * Accept a connection. Essentially all the work is 206 * done at higher levels; just return the address 207 * of the peer, storing through addr. 208 */ 209 case PRU_ACCEPT: { 210 struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *); 211 212 nam->m_len = sizeof (struct sockaddr_in); 213 sin->sin_family = AF_INET; 214 sin->sin_port = inp->inp_fport; 215 sin->sin_addr = inp->inp_faddr; 216 break; 217 } 218 219 /* 220 * Mark the connection as being incapable of further output. 221 */ 222 case PRU_SHUTDOWN: 223 socantsendmore(so); 224 tp = tcp_usrclosed(tp); 225 if (tp) 226 error = tcp_output(tp); 227 break; 228 229 /* 230 * After a receive, possibly send window update to peer. 231 */ 232 case PRU_RCVD: 233 (void) tcp_output(tp); 234 break; 235 236 /* 237 * Do a send by putting data in output queue and updating urgent 238 * marker if URG set. Possibly send more data. 239 */ 240 case PRU_SEND: 241 sbappend(&so->so_snd, m); 242 error = tcp_output(tp); 243 break; 244 245 /* 246 * Abort the TCP. 247 */ 248 case PRU_ABORT: 249 tp = tcp_drop(tp, ECONNABORTED); 250 break; 251 252 case PRU_SENSE: 253 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 254 (void) splx(s); 255 return (0); 256 257 case PRU_RCVOOB: 258 if ((so->so_oobmark == 0 && 259 (so->so_state & SS_RCVATMARK) == 0) || 260 #ifdef SO_OOBINLINE 261 so->so_options & SO_OOBINLINE || 262 #endif 263 tp->t_oobflags & TCPOOB_HADDATA) { 264 error = EINVAL; 265 break; 266 } 267 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 268 error = EWOULDBLOCK; 269 break; 270 } 271 m->m_len = 1; 272 *mtod(m, caddr_t) = tp->t_iobc; 273 if (((int)nam & MSG_PEEK) == 0) 274 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 275 break; 276 277 case PRU_SENDOOB: 278 if (sbspace(&so->so_snd) < -512) { 279 m_freem(m); 280 error = ENOBUFS; 281 break; 282 } 283 /* 284 * According to RFC961 (Assigned Protocols), 285 * the urgent pointer points to the last octet 286 * of urgent data. We continue, however, 287 * to consider it to indicate the first octet 288 * of data past the urgent section. 289 * Otherwise, snd_up should be one lower. 290 */ 291 sbappend(&so->so_snd, m); 292 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 293 tp->t_force = 1; 294 error = tcp_output(tp); 295 tp->t_force = 0; 296 break; 297 298 case PRU_SOCKADDR: 299 in_setsockaddr(inp, nam); 300 break; 301 302 case PRU_PEERADDR: 303 in_setpeeraddr(inp, nam); 304 break; 305 306 /* 307 * TCP slow timer went off; going through this 308 * routine for tracing's sake. 309 */ 310 case PRU_SLOWTIMO: 311 tp = tcp_timers(tp, (int)nam); 312 req |= (int)nam << 8; /* for debug's sake */ 313 break; 314 315 default: 316 panic("tcp_usrreq"); 317 } 318 if (tp && (so->so_options & SO_DEBUG)) 319 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 320 splx(s); 321 return (error); 322 } 323 324 #if BSD>=43 325 tcp_ctloutput(op, so, level, optname, mp) 326 int op; 327 struct socket *so; 328 int level, optname; 329 struct mbuf **mp; 330 { 331 int error = 0; 332 struct inpcb *inp = sotoinpcb(so); 333 register struct tcpcb *tp = intotcpcb(inp); 334 register struct mbuf *m; 335 336 if (level != IPPROTO_TCP) 337 return (ip_ctloutput(op, so, level, optname, mp)); 338 339 switch (op) { 340 341 case PRCO_SETOPT: 342 m = *mp; 343 switch (optname) { 344 345 case TCP_NODELAY: 346 if (m == NULL || m->m_len < sizeof (int)) 347 error = EINVAL; 348 else if (*mtod(m, int *)) 349 tp->t_flags |= TF_NODELAY; 350 else 351 tp->t_flags &= ~TF_NODELAY; 352 break; 353 354 case TCP_MAXSEG: /* not yet */ 355 default: 356 error = EINVAL; 357 break; 358 } 359 if (m) 360 (void) m_free(m); 361 break; 362 363 case PRCO_GETOPT: 364 *mp = m = m_get(M_WAIT, MT_SOOPTS); 365 m->m_len = sizeof(int); 366 367 switch (optname) { 368 case TCP_NODELAY: 369 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 370 break; 371 case TCP_MAXSEG: 372 *mtod(m, int *) = tp->t_maxseg; 373 break; 374 default: 375 error = EINVAL; 376 break; 377 } 378 break; 379 } 380 return (error); 381 } 382 #endif 383 384 u_long tcp_sendspace = 1024*4; 385 u_long tcp_recvspace = 1024*4; 386 /* 387 * Attach TCP protocol to socket, allocating 388 * internet protocol control block, tcp control block, 389 * bufer space, and entering LISTEN state if to accept connections. 390 */ 391 tcp_attach(so) 392 struct socket *so; 393 { 394 register struct tcpcb *tp; 395 struct inpcb *inp; 396 int error; 397 398 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 399 error = soreserve(so, tcp_sendspace, tcp_recvspace); 400 if (error) 401 return (error); 402 } 403 error = in_pcballoc(so, &tcb); 404 if (error) 405 return (error); 406 inp = sotoinpcb(so); 407 tp = tcp_newtcpcb(inp); 408 if (tp == 0) { 409 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 410 411 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 412 in_pcbdetach(inp); 413 so->so_state |= nofd; 414 return (ENOBUFS); 415 } 416 tp->t_state = TCPS_CLOSED; 417 return (0); 418 } 419 420 /* 421 * Initiate (or continue) disconnect. 422 * If embryonic state, just send reset (once). 423 * If in ``let data drain'' option and linger null, just drop. 424 * Otherwise (hard), mark socket disconnecting and drop 425 * current input data; switch states based on user close, and 426 * send segment to peer (with FIN). 427 */ 428 struct tcpcb * 429 tcp_disconnect(tp) 430 register struct tcpcb *tp; 431 { 432 struct socket *so = tp->t_inpcb->inp_socket; 433 434 if (tp->t_state < TCPS_ESTABLISHED) 435 tp = tcp_close(tp); 436 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 437 tp = tcp_drop(tp, 0); 438 else { 439 soisdisconnecting(so); 440 sbflush(&so->so_rcv); 441 tp = tcp_usrclosed(tp); 442 if (tp) 443 (void) tcp_output(tp); 444 } 445 return (tp); 446 } 447 448 /* 449 * User issued close, and wish to trail through shutdown states: 450 * if never received SYN, just forget it. If got a SYN from peer, 451 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 452 * If already got a FIN from peer, then almost done; go to LAST_ACK 453 * state. In all other cases, have already sent FIN to peer (e.g. 454 * after PRU_SHUTDOWN), and just have to play tedious game waiting 455 * for peer to send FIN or not respond to keep-alives, etc. 456 * We can let the user exit from the close as soon as the FIN is acked. 457 */ 458 struct tcpcb * 459 tcp_usrclosed(tp) 460 register struct tcpcb *tp; 461 { 462 463 switch (tp->t_state) { 464 465 case TCPS_CLOSED: 466 case TCPS_LISTEN: 467 case TCPS_SYN_SENT: 468 tp->t_state = TCPS_CLOSED; 469 tp = tcp_close(tp); 470 break; 471 472 case TCPS_SYN_RECEIVED: 473 case TCPS_ESTABLISHED: 474 tp->t_state = TCPS_FIN_WAIT_1; 475 break; 476 477 case TCPS_CLOSE_WAIT: 478 tp->t_state = TCPS_LAST_ACK; 479 break; 480 } 481 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 482 soisdisconnected(tp->t_inpcb->inp_socket); 483 return (tp); 484 } 485