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 7.1 (Berkeley) 06/05/86 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 return (in_control(so, (int)m, (caddr_t)nam, 60 (struct ifnet *)rights)); 61 if (rights && rights->m_len) { 62 splx(s); 63 return (EINVAL); 64 } 65 /* 66 * When a TCP is attached to a socket, then there will be 67 * a (struct inpcb) pointed at by the socket, and this 68 * structure will point at a subsidary (struct tcpcb). 69 */ 70 if (inp == 0 && req != PRU_ATTACH) { 71 splx(s); 72 return (EINVAL); /* XXX */ 73 } 74 if (inp) { 75 tp = intotcpcb(inp); 76 /* WHAT IF TP IS 0? */ 77 #ifdef KPROF 78 tcp_acounts[tp->t_state][req]++; 79 #endif 80 ostate = tp->t_state; 81 } else 82 ostate = 0; 83 switch (req) { 84 85 /* 86 * TCP attaches to socket via PRU_ATTACH, reserving space, 87 * and an internet control block. 88 */ 89 case PRU_ATTACH: 90 if (inp) { 91 error = EISCONN; 92 break; 93 } 94 error = tcp_attach(so); 95 if (error) 96 break; 97 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 98 so->so_linger = TCP_LINGERTIME; 99 tp = sototcpcb(so); 100 break; 101 102 /* 103 * PRU_DETACH detaches the TCP protocol from the socket. 104 * If the protocol state is non-embryonic, then can't 105 * do this directly: have to initiate a PRU_DISCONNECT, 106 * which may finish later; embryonic TCB's can just 107 * be discarded here. 108 */ 109 case PRU_DETACH: 110 if (tp->t_state > TCPS_LISTEN) 111 tp = tcp_disconnect(tp); 112 else 113 tp = tcp_close(tp); 114 break; 115 116 /* 117 * Give the socket an address. 118 */ 119 case PRU_BIND: 120 error = in_pcbbind(inp, nam); 121 if (error) 122 break; 123 break; 124 125 /* 126 * Prepare to accept connections. 127 */ 128 case PRU_LISTEN: 129 if (inp->inp_lport == 0) 130 error = in_pcbbind(inp, (struct mbuf *)0); 131 if (error == 0) 132 tp->t_state = TCPS_LISTEN; 133 break; 134 135 /* 136 * Initiate connection to peer. 137 * Create a template for use in transmissions on this connection. 138 * Enter SYN_SENT state, and mark socket as connecting. 139 * Start keep-alive timer, and seed output sequence space. 140 * Send initial segment on connection. 141 */ 142 case PRU_CONNECT: 143 if (inp->inp_lport == 0) { 144 error = in_pcbbind(inp, (struct mbuf *)0); 145 if (error) 146 break; 147 } 148 error = in_pcbconnect(inp, nam); 149 if (error) 150 break; 151 tp->t_template = tcp_template(tp); 152 if (tp->t_template == 0) { 153 in_pcbdisconnect(inp); 154 error = ENOBUFS; 155 break; 156 } 157 soisconnecting(so); 158 tp->t_state = TCPS_SYN_SENT; 159 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 160 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 161 tcp_sendseqinit(tp); 162 error = tcp_output(tp); 163 break; 164 165 /* 166 * Create a TCP connection between two sockets. 167 */ 168 case PRU_CONNECT2: 169 error = EOPNOTSUPP; 170 break; 171 172 /* 173 * Initiate disconnect from peer. 174 * If connection never passed embryonic stage, just drop; 175 * else if don't need to let data drain, then can just drop anyways, 176 * else have to begin TCP shutdown process: mark socket disconnecting, 177 * drain unread data, state switch to reflect user close, and 178 * send segment (e.g. FIN) to peer. Socket will be really disconnected 179 * when peer sends FIN and acks ours. 180 * 181 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 182 */ 183 case PRU_DISCONNECT: 184 tp = tcp_disconnect(tp); 185 break; 186 187 /* 188 * Accept a connection. Essentially all the work is 189 * done at higher levels; just return the address 190 * of the peer, storing through addr. 191 */ 192 case PRU_ACCEPT: { 193 struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *); 194 195 nam->m_len = sizeof (struct sockaddr_in); 196 sin->sin_family = AF_INET; 197 sin->sin_port = inp->inp_fport; 198 sin->sin_addr = inp->inp_faddr; 199 break; 200 } 201 202 /* 203 * Mark the connection as being incapable of further output. 204 */ 205 case PRU_SHUTDOWN: 206 socantsendmore(so); 207 tp = tcp_usrclosed(tp); 208 if (tp) 209 error = tcp_output(tp); 210 break; 211 212 /* 213 * After a receive, possibly send window update to peer. 214 */ 215 case PRU_RCVD: 216 (void) tcp_output(tp); 217 break; 218 219 /* 220 * Do a send by putting data in output queue and updating urgent 221 * marker if URG set. Possibly send more data. 222 */ 223 case PRU_SEND: 224 sbappend(&so->so_snd, m); 225 #ifdef notdef 226 if (tp->t_flags & TF_PUSH) 227 tp->snd_end = tp->snd_una + so->so_snd.sb_cc; 228 #endif 229 error = tcp_output(tp); 230 if (error) { /* XXX fix to use other path */ 231 if (error == ENOBUFS) /* XXX */ 232 error = 0; /* XXX */ 233 tcpsenderrors++; 234 } 235 break; 236 237 /* 238 * Abort the TCP. 239 */ 240 case PRU_ABORT: 241 tp = tcp_drop(tp, ECONNABORTED); 242 break; 243 244 case PRU_SENSE: 245 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 246 return (0); 247 248 case PRU_RCVOOB: 249 if ((so->so_oobmark == 0 && 250 (so->so_state & SS_RCVATMARK) == 0) || 251 so->so_options & SO_OOBINLINE || 252 tp->t_oobflags & TCPOOB_HADDATA) { 253 error = EINVAL; 254 break; 255 } 256 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 257 error = EWOULDBLOCK; 258 break; 259 } 260 m->m_len = 1; 261 *mtod(m, caddr_t) = tp->t_iobc; 262 if (((int)nam & MSG_PEEK) == 0) 263 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 264 break; 265 266 case PRU_SENDOOB: 267 if (sbspace(&so->so_snd) < -512) { 268 m_freem(m); 269 error = ENOBUFS; 270 break; 271 } 272 /* 273 * According to RFC961 (Assigned Protocols), 274 * the urgent pointer points to the last octet 275 * of urgent data. We continue, however, 276 * to consider it to indicate the first octet 277 * of data past the urgent section. 278 * Otherwise, snd_up should be one lower. 279 */ 280 sbappend(&so->so_snd, m); 281 tp->snd_up = tp->snd_una + so->so_snd.sb_cc; 282 tp->t_force = 1; 283 error = tcp_output(tp); 284 tp->t_force = 0; 285 break; 286 287 case PRU_SOCKADDR: 288 in_setsockaddr(inp, nam); 289 break; 290 291 case PRU_PEERADDR: 292 in_setpeeraddr(inp, nam); 293 break; 294 295 /* 296 * TCP slow timer went off; going through this 297 * routine for tracing's sake. 298 */ 299 case PRU_SLOWTIMO: 300 tp = tcp_timers(tp, (int)nam); 301 req |= (int)nam << 8; /* for debug's sake */ 302 break; 303 304 default: 305 panic("tcp_usrreq"); 306 } 307 if (tp && (so->so_options & SO_DEBUG)) 308 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 309 splx(s); 310 return (error); 311 } 312 313 tcp_ctloutput(op, so, level, optname, mp) 314 int op; 315 struct socket *so; 316 int level, optname; 317 struct mbuf **mp; 318 { 319 int error = 0; 320 struct inpcb *inp = sotoinpcb(so); 321 register struct tcpcb *tp = intotcpcb(inp); 322 register struct mbuf *m; 323 324 if (level != IPPROTO_TCP) 325 return (ip_ctloutput(op, so, level, optname, mp)); 326 327 switch (op) { 328 329 case PRCO_SETOPT: 330 m = *mp; 331 switch (optname) { 332 333 case TCP_NODELAY: 334 if (m == NULL || m->m_len < sizeof (int)) 335 error = EINVAL; 336 else if (*mtod(m, int *)) 337 tp->t_flags |= TF_NODELAY; 338 else 339 tp->t_flags &= ~TF_NODELAY; 340 break; 341 342 case TCP_MAXSEG: /* not yet */ 343 default: 344 error = EINVAL; 345 break; 346 } 347 (void)m_free(m); 348 break; 349 350 case PRCO_GETOPT: 351 *mp = m = m_get(M_WAIT, MT_SOOPTS); 352 m->m_len = sizeof(int); 353 354 switch (optname) { 355 case TCP_NODELAY: 356 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 357 break; 358 case TCP_MAXSEG: 359 *mtod(m, int *) = tp->t_maxseg; 360 break; 361 default: 362 error = EINVAL; 363 break; 364 } 365 break; 366 } 367 return (error); 368 } 369 370 int tcp_sendspace = 1024*4; 371 int tcp_recvspace = 1024*4; 372 /* 373 * Attach TCP protocol to socket, allocating 374 * internet protocol control block, tcp control block, 375 * bufer space, and entering LISTEN state if to accept connections. 376 */ 377 tcp_attach(so) 378 struct socket *so; 379 { 380 register struct tcpcb *tp; 381 struct inpcb *inp; 382 int error; 383 384 error = soreserve(so, tcp_sendspace, tcp_recvspace); 385 if (error) 386 return (error); 387 error = in_pcballoc(so, &tcb); 388 if (error) 389 return (error); 390 inp = sotoinpcb(so); 391 tp = tcp_newtcpcb(inp); 392 if (tp == 0) { 393 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 394 395 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 396 in_pcbdetach(inp); 397 so->so_state |= nofd; 398 return (ENOBUFS); 399 } 400 tp->t_state = TCPS_CLOSED; 401 return (0); 402 } 403 404 /* 405 * Initiate (or continue) disconnect. 406 * If embryonic state, just send reset (once). 407 * If in ``let data drain'' option and linger null, just drop. 408 * Otherwise (hard), mark socket disconnecting and drop 409 * current input data; switch states based on user close, and 410 * send segment to peer (with FIN). 411 */ 412 struct tcpcb * 413 tcp_disconnect(tp) 414 register struct tcpcb *tp; 415 { 416 struct socket *so = tp->t_inpcb->inp_socket; 417 418 if (tp->t_state < TCPS_ESTABLISHED) 419 tp = tcp_close(tp); 420 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 421 tp = tcp_drop(tp, 0); 422 else { 423 soisdisconnecting(so); 424 sbflush(&so->so_rcv); 425 tp = tcp_usrclosed(tp); 426 if (tp) 427 (void) tcp_output(tp); 428 } 429 return (tp); 430 } 431 432 /* 433 * User issued close, and wish to trail through shutdown states: 434 * if never received SYN, just forget it. If got a SYN from peer, 435 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 436 * If already got a FIN from peer, then almost done; go to LAST_ACK 437 * state. In all other cases, have already sent FIN to peer (e.g. 438 * after PRU_SHUTDOWN), and just have to play tedious game waiting 439 * for peer to send FIN or not respond to keep-alives, etc. 440 * We can let the user exit from the close as soon as the FIN is acked. 441 */ 442 struct tcpcb * 443 tcp_usrclosed(tp) 444 register struct tcpcb *tp; 445 { 446 447 switch (tp->t_state) { 448 449 case TCPS_CLOSED: 450 case TCPS_LISTEN: 451 case TCPS_SYN_SENT: 452 tp->t_state = TCPS_CLOSED; 453 tp = tcp_close(tp); 454 break; 455 456 case TCPS_SYN_RECEIVED: 457 case TCPS_ESTABLISHED: 458 tp->t_state = TCPS_FIN_WAIT_1; 459 break; 460 461 case TCPS_CLOSE_WAIT: 462 tp->t_state = TCPS_LAST_ACK; 463 break; 464 } 465 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 466 soisdisconnected(tp->t_inpcb->inp_socket); 467 return (tp); 468 } 469