1 /* 2 * Copyright (c) 1982, 1986 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)tcp_usrreq.c 7.3 (Berkeley) 04/09/87 7 */ 8 9 #include "param.h" 10 #include "systm.h" 11 #include "mbuf.h" 12 #include "socket.h" 13 #include "socketvar.h" 14 #include "protosw.h" 15 #include "errno.h" 16 #include "stat.h" 17 18 #include "../net/if.h" 19 #include "../net/route.h" 20 21 #include "in.h" 22 #include "in_pcb.h" 23 #include "in_systm.h" 24 #include "ip.h" 25 #include "ip_var.h" 26 #include "tcp.h" 27 #include "tcp_fsm.h" 28 #include "tcp_seq.h" 29 #include "tcp_timer.h" 30 #include "tcp_var.h" 31 #include "tcpip.h" 32 #include "tcp_debug.h" 33 34 /* 35 * TCP protocol interface to socket abstraction. 36 */ 37 extern char *tcpstates[]; 38 struct tcpcb *tcp_newtcpcb(); 39 int tcpsenderrors; 40 41 /* 42 * Process a TCP user request for TCP tb. If this is a send request 43 * then m is the mbuf chain of send data. If this is a timer expiration 44 * (called from the software clock routine), then timertype tells which timer. 45 */ 46 /*ARGSUSED*/ 47 tcp_usrreq(so, req, m, nam, rights) 48 struct socket *so; 49 int req; 50 struct mbuf *m, *nam, *rights; 51 { 52 register struct inpcb *inp = sotoinpcb(so); 53 register struct tcpcb *tp; 54 int s = splnet(); 55 int error = 0; 56 int ostate; 57 58 if (req == PRU_CONTROL) { 59 error = in_control(so, (int)m, (caddr_t)nam, 60 (struct ifnet *)rights); 61 (void) splx(s); 62 return(error); 63 } 64 if (rights && rights->m_len) { 65 splx(s); 66 return (EINVAL); 67 } 68 /* 69 * When a TCP is attached to a socket, then there will be 70 * a (struct inpcb) pointed at by the socket, and this 71 * structure will point at a subsidary (struct tcpcb). 72 */ 73 if (inp == 0 && req != PRU_ATTACH) { 74 splx(s); 75 return (EINVAL); /* XXX */ 76 } 77 if (inp) { 78 tp = intotcpcb(inp); 79 /* WHAT IF TP IS 0? */ 80 #ifdef KPROF 81 tcp_acounts[tp->t_state][req]++; 82 #endif 83 ostate = tp->t_state; 84 } else 85 ostate = 0; 86 switch (req) { 87 88 /* 89 * TCP attaches to socket via PRU_ATTACH, reserving space, 90 * and an internet control block. 91 */ 92 case PRU_ATTACH: 93 if (inp) { 94 error = EISCONN; 95 break; 96 } 97 error = tcp_attach(so); 98 if (error) 99 break; 100 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 101 so->so_linger = TCP_LINGERTIME; 102 tp = sototcpcb(so); 103 break; 104 105 /* 106 * PRU_DETACH detaches the TCP protocol from the socket. 107 * If the protocol state is non-embryonic, then can't 108 * do this directly: have to initiate a PRU_DISCONNECT, 109 * which may finish later; embryonic TCB's can just 110 * be discarded here. 111 */ 112 case PRU_DETACH: 113 if (tp->t_state > TCPS_LISTEN) 114 tp = tcp_disconnect(tp); 115 else 116 tp = tcp_close(tp); 117 break; 118 119 /* 120 * Give the socket an address. 121 */ 122 case PRU_BIND: 123 error = in_pcbbind(inp, nam); 124 if (error) 125 break; 126 break; 127 128 /* 129 * Prepare to accept connections. 130 */ 131 case PRU_LISTEN: 132 if (inp->inp_lport == 0) 133 error = in_pcbbind(inp, (struct mbuf *)0); 134 if (error == 0) 135 tp->t_state = TCPS_LISTEN; 136 break; 137 138 /* 139 * Initiate connection to peer. 140 * Create a template for use in transmissions on this connection. 141 * Enter SYN_SENT state, and mark socket as connecting. 142 * Start keep-alive timer, and seed output sequence space. 143 * Send initial segment on connection. 144 */ 145 case PRU_CONNECT: 146 if (inp->inp_lport == 0) { 147 error = in_pcbbind(inp, (struct mbuf *)0); 148 if (error) 149 break; 150 } 151 error = in_pcbconnect(inp, nam); 152 if (error) 153 break; 154 tp->t_template = tcp_template(tp); 155 if (tp->t_template == 0) { 156 in_pcbdisconnect(inp); 157 error = ENOBUFS; 158 break; 159 } 160 soisconnecting(so); 161 tcpstat.tcps_connattempt++; 162 tp->t_state = TCPS_SYN_SENT; 163 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 164 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 165 tcp_sendseqinit(tp); 166 error = tcp_output(tp); 167 break; 168 169 /* 170 * Create a TCP connection between two sockets. 171 */ 172 case PRU_CONNECT2: 173 error = EOPNOTSUPP; 174 break; 175 176 /* 177 * Initiate disconnect from peer. 178 * If connection never passed embryonic stage, just drop; 179 * else if don't need to let data drain, then can just drop anyways, 180 * else have to begin TCP shutdown process: mark socket disconnecting, 181 * drain unread data, state switch to reflect user close, and 182 * send segment (e.g. FIN) to peer. Socket will be really disconnected 183 * when peer sends FIN and acks ours. 184 * 185 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 186 */ 187 case PRU_DISCONNECT: 188 tp = tcp_disconnect(tp); 189 break; 190 191 /* 192 * Accept a connection. Essentially all the work is 193 * done at higher levels; just return the address 194 * of the peer, storing through addr. 195 */ 196 case PRU_ACCEPT: { 197 struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *); 198 199 nam->m_len = sizeof (struct sockaddr_in); 200 sin->sin_family = AF_INET; 201 sin->sin_port = inp->inp_fport; 202 sin->sin_addr = inp->inp_faddr; 203 break; 204 } 205 206 /* 207 * Mark the connection as being incapable of further output. 208 */ 209 case PRU_SHUTDOWN: 210 socantsendmore(so); 211 tp = tcp_usrclosed(tp); 212 if (tp) 213 error = tcp_output(tp); 214 break; 215 216 /* 217 * After a receive, possibly send window update to peer. 218 */ 219 case PRU_RCVD: 220 (void) tcp_output(tp); 221 break; 222 223 /* 224 * Do a send by putting data in output queue and updating urgent 225 * marker if URG set. Possibly send more data. 226 */ 227 case PRU_SEND: 228 sbappend(&so->so_snd, m); 229 #ifdef notdef 230 if (tp->t_flags & TF_PUSH) 231 tp->snd_end = tp->snd_una + so->so_snd.sb_cc; 232 #endif 233 error = tcp_output(tp); 234 if (error) { /* XXX fix to use other path */ 235 if (error == ENOBUFS) /* XXX */ 236 error = 0; /* XXX */ 237 tcpsenderrors++; 238 } 239 break; 240 241 /* 242 * Abort the TCP. 243 */ 244 case PRU_ABORT: 245 tp = tcp_drop(tp, ECONNABORTED); 246 break; 247 248 case PRU_SENSE: 249 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 250 (void) splx(s); 251 return (0); 252 253 case PRU_RCVOOB: 254 if ((so->so_oobmark == 0 && 255 (so->so_state & SS_RCVATMARK) == 0) || 256 so->so_options & SO_OOBINLINE || 257 tp->t_oobflags & TCPOOB_HADDATA) { 258 error = EINVAL; 259 break; 260 } 261 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 262 error = EWOULDBLOCK; 263 break; 264 } 265 m->m_len = 1; 266 *mtod(m, caddr_t) = tp->t_iobc; 267 if (((int)nam & MSG_PEEK) == 0) 268 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 269 break; 270 271 case PRU_SENDOOB: 272 if (sbspace(&so->so_snd) < -512) { 273 m_freem(m); 274 error = ENOBUFS; 275 break; 276 } 277 /* 278 * According to RFC961 (Assigned Protocols), 279 * the urgent pointer points to the last octet 280 * of urgent data. We continue, however, 281 * to consider it to indicate the first octet 282 * of data past the urgent section. 283 * Otherwise, snd_up should be one lower. 284 */ 285 sbappend(&so->so_snd, m); 286 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 287 tp->t_force = 1; 288 error = tcp_output(tp); 289 tp->t_force = 0; 290 break; 291 292 case PRU_SOCKADDR: 293 in_setsockaddr(inp, nam); 294 break; 295 296 case PRU_PEERADDR: 297 in_setpeeraddr(inp, nam); 298 break; 299 300 /* 301 * TCP slow timer went off; going through this 302 * routine for tracing's sake. 303 */ 304 case PRU_SLOWTIMO: 305 tp = tcp_timers(tp, (int)nam); 306 req |= (int)nam << 8; /* for debug's sake */ 307 break; 308 309 default: 310 panic("tcp_usrreq"); 311 } 312 if (tp && (so->so_options & SO_DEBUG)) 313 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 314 splx(s); 315 return (error); 316 } 317 318 tcp_ctloutput(op, so, level, optname, mp) 319 int op; 320 struct socket *so; 321 int level, optname; 322 struct mbuf **mp; 323 { 324 int error = 0; 325 struct inpcb *inp = sotoinpcb(so); 326 register struct tcpcb *tp = intotcpcb(inp); 327 register struct mbuf *m; 328 329 if (level != IPPROTO_TCP) 330 return (ip_ctloutput(op, so, level, optname, mp)); 331 332 switch (op) { 333 334 case PRCO_SETOPT: 335 m = *mp; 336 switch (optname) { 337 338 case TCP_NODELAY: 339 if (m == NULL || m->m_len < sizeof (int)) 340 error = EINVAL; 341 else if (*mtod(m, int *)) 342 tp->t_flags |= TF_NODELAY; 343 else 344 tp->t_flags &= ~TF_NODELAY; 345 break; 346 347 case TCP_MAXSEG: /* not yet */ 348 default: 349 error = EINVAL; 350 break; 351 } 352 (void)m_free(m); 353 break; 354 355 case PRCO_GETOPT: 356 *mp = m = m_get(M_WAIT, MT_SOOPTS); 357 m->m_len = sizeof(int); 358 359 switch (optname) { 360 case TCP_NODELAY: 361 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 362 break; 363 case TCP_MAXSEG: 364 *mtod(m, int *) = tp->t_maxseg; 365 break; 366 default: 367 error = EINVAL; 368 break; 369 } 370 break; 371 } 372 return (error); 373 } 374 375 int tcp_sendspace = 1024*4; 376 int tcp_recvspace = 1024*4; 377 /* 378 * Attach TCP protocol to socket, allocating 379 * internet protocol control block, tcp control block, 380 * bufer space, and entering LISTEN state if to accept connections. 381 */ 382 tcp_attach(so) 383 struct socket *so; 384 { 385 register struct tcpcb *tp; 386 struct inpcb *inp; 387 int error; 388 389 error = soreserve(so, tcp_sendspace, tcp_recvspace); 390 if (error) 391 return (error); 392 error = in_pcballoc(so, &tcb); 393 if (error) 394 return (error); 395 inp = sotoinpcb(so); 396 tp = tcp_newtcpcb(inp); 397 if (tp == 0) { 398 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 399 400 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 401 in_pcbdetach(inp); 402 so->so_state |= nofd; 403 return (ENOBUFS); 404 } 405 tp->t_state = TCPS_CLOSED; 406 return (0); 407 } 408 409 /* 410 * Initiate (or continue) disconnect. 411 * If embryonic state, just send reset (once). 412 * If in ``let data drain'' option and linger null, just drop. 413 * Otherwise (hard), mark socket disconnecting and drop 414 * current input data; switch states based on user close, and 415 * send segment to peer (with FIN). 416 */ 417 struct tcpcb * 418 tcp_disconnect(tp) 419 register struct tcpcb *tp; 420 { 421 struct socket *so = tp->t_inpcb->inp_socket; 422 423 if (tp->t_state < TCPS_ESTABLISHED) 424 tp = tcp_close(tp); 425 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 426 tp = tcp_drop(tp, 0); 427 else { 428 soisdisconnecting(so); 429 sbflush(&so->so_rcv); 430 tp = tcp_usrclosed(tp); 431 if (tp) 432 (void) tcp_output(tp); 433 } 434 return (tp); 435 } 436 437 /* 438 * User issued close, and wish to trail through shutdown states: 439 * if never received SYN, just forget it. If got a SYN from peer, 440 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 441 * If already got a FIN from peer, then almost done; go to LAST_ACK 442 * state. In all other cases, have already sent FIN to peer (e.g. 443 * after PRU_SHUTDOWN), and just have to play tedious game waiting 444 * for peer to send FIN or not respond to keep-alives, etc. 445 * We can let the user exit from the close as soon as the FIN is acked. 446 */ 447 struct tcpcb * 448 tcp_usrclosed(tp) 449 register struct tcpcb *tp; 450 { 451 452 switch (tp->t_state) { 453 454 case TCPS_CLOSED: 455 case TCPS_LISTEN: 456 case TCPS_SYN_SENT: 457 tp->t_state = TCPS_CLOSED; 458 tp = tcp_close(tp); 459 break; 460 461 case TCPS_SYN_RECEIVED: 462 case TCPS_ESTABLISHED: 463 tp->t_state = TCPS_FIN_WAIT_1; 464 break; 465 466 case TCPS_CLOSE_WAIT: 467 tp->t_state = TCPS_LAST_ACK; 468 break; 469 } 470 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 471 soisdisconnected(tp->t_inpcb->inp_socket); 472 return (tp); 473 } 474