1 /* 2 * Copyright (c) 1982 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 6.8 (Berkeley) 01/13/86 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 tp->t_oobflags & TCPOOB_HADDATA) { 252 error = EINVAL; 253 break; 254 } 255 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 256 error = EWOULDBLOCK; 257 break; 258 } 259 m->m_len = 1; 260 *mtod(m, caddr_t) = tp->t_iobc; 261 if (((int)nam & MSG_PEEK) == 0) 262 tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA); 263 break; 264 265 case PRU_SENDOOB: 266 if (sbspace(&so->so_snd) < -512) { 267 m_freem(m); 268 error = ENOBUFS; 269 break; 270 } 271 tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1; 272 sbappend(&so->so_snd, m); 273 tp->t_force = 1; 274 error = tcp_output(tp); 275 tp->t_force = 0; 276 break; 277 278 case PRU_SOCKADDR: 279 in_setsockaddr(inp, nam); 280 break; 281 282 case PRU_PEERADDR: 283 in_setpeeraddr(inp, nam); 284 break; 285 286 /* 287 * TCP slow timer went off; going through this 288 * routine for tracing's sake. 289 */ 290 case PRU_SLOWTIMO: 291 tp = tcp_timers(tp, (int)nam); 292 req |= (int)nam << 8; /* for debug's sake */ 293 break; 294 295 default: 296 panic("tcp_usrreq"); 297 } 298 if (tp && (so->so_options & SO_DEBUG)) 299 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 300 splx(s); 301 return (error); 302 } 303 304 tcp_ctloutput(op, so, level, optname, mp) 305 int op; 306 struct socket *so; 307 int level, optname; 308 struct mbuf **mp; 309 { 310 int error = 0; 311 struct inpcb *inp = sotoinpcb(so); 312 register struct tcpcb *tp = intotcpcb(inp); 313 register struct mbuf *m; 314 315 if (level != IPPROTO_TCP) 316 return (ip_ctloutput(op, so, level, optname, m)); 317 318 switch (op) { 319 320 case PRCO_SETOPT: 321 m = *mp; 322 switch (optname) { 323 324 case TCP_NODELAY: 325 if (m == NULL || m->m_len < sizeof (int)) 326 error = EINVAL; 327 else if (*mtod(m, int *)) 328 tp->t_flags |= TF_NODELAY; 329 else 330 tp->t_flags &= ~TF_NODELAY; 331 break; 332 333 case TCP_MAXSEG: /* not yet */ 334 default: 335 error = EINVAL; 336 break; 337 } 338 m_free(m); 339 break; 340 341 case PRCO_GETOPT: 342 *mp = m = m_get(M_WAIT, MT_SOOPTS); 343 m->m_len = sizeof(int); 344 345 switch (optname) { 346 case TCP_NODELAY: 347 *mtod(m, int *) = tp->t_flags & TF_NODELAY; 348 break; 349 case TCP_MAXSEG: 350 *mtod(m, int *) = tp->t_maxseg; 351 break; 352 default: 353 error = EINVAL; 354 break; 355 } 356 break; 357 } 358 return (error); 359 } 360 361 int tcp_sendspace = 1024*4; 362 int tcp_recvspace = 1024*4; 363 /* 364 * Attach TCP protocol to socket, allocating 365 * internet protocol control block, tcp control block, 366 * bufer space, and entering LISTEN state if to accept connections. 367 */ 368 tcp_attach(so) 369 struct socket *so; 370 { 371 register struct tcpcb *tp; 372 struct inpcb *inp; 373 int error; 374 375 error = soreserve(so, tcp_sendspace, tcp_recvspace); 376 if (error) 377 return (error); 378 error = in_pcballoc(so, &tcb); 379 if (error) 380 return (error); 381 inp = sotoinpcb(so); 382 tp = tcp_newtcpcb(inp); 383 if (tp == 0) { 384 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 385 386 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 387 in_pcbdetach(inp); 388 so->so_state |= nofd; 389 return (ENOBUFS); 390 } 391 tp->t_state = TCPS_CLOSED; 392 return (0); 393 } 394 395 /* 396 * Initiate (or continue) disconnect. 397 * If embryonic state, just send reset (once). 398 * If in ``let data drain'' option and linger null, just drop. 399 * Otherwise (hard), mark socket disconnecting and drop 400 * current input data; switch states based on user close, and 401 * send segment to peer (with FIN). 402 */ 403 struct tcpcb * 404 tcp_disconnect(tp) 405 register struct tcpcb *tp; 406 { 407 struct socket *so = tp->t_inpcb->inp_socket; 408 409 if (tp->t_state < TCPS_ESTABLISHED) 410 tp = tcp_close(tp); 411 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 412 tp = tcp_drop(tp, 0); 413 else { 414 soisdisconnecting(so); 415 sbflush(&so->so_rcv); 416 tp = tcp_usrclosed(tp); 417 if (tp) 418 (void) tcp_output(tp); 419 } 420 return (tp); 421 } 422 423 /* 424 * User issued close, and wish to trail through shutdown states: 425 * if never received SYN, just forget it. If got a SYN from peer, 426 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 427 * If already got a FIN from peer, then almost done; go to LAST_ACK 428 * state. In all other cases, have already sent FIN to peer (e.g. 429 * after PRU_SHUTDOWN), and just have to play tedious game waiting 430 * for peer to send FIN or not respond to keep-alives, etc. 431 * We can let the user exit from the close as soon as the FIN is acked. 432 */ 433 struct tcpcb * 434 tcp_usrclosed(tp) 435 register struct tcpcb *tp; 436 { 437 438 switch (tp->t_state) { 439 440 case TCPS_CLOSED: 441 case TCPS_LISTEN: 442 case TCPS_SYN_SENT: 443 tp->t_state = TCPS_CLOSED; 444 tp = tcp_close(tp); 445 break; 446 447 case TCPS_SYN_RECEIVED: 448 case TCPS_ESTABLISHED: 449 tp->t_state = TCPS_FIN_WAIT_1; 450 break; 451 452 case TCPS_CLOSE_WAIT: 453 tp->t_state = TCPS_LAST_ACK; 454 break; 455 } 456 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 457 soisdisconnected(tp->t_inpcb->inp_socket); 458 return (tp); 459 } 460