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 6.6 (Berkeley) 06/08/85 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 error = EINVAL; 252 break; 253 } 254 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 255 error = EWOULDBLOCK; 256 break; 257 } 258 m->m_len = 1; 259 *mtod(m, caddr_t) = tp->t_iobc; 260 break; 261 262 case PRU_SENDOOB: 263 if (sbspace(&so->so_snd) < -512) { 264 m_freem(m); 265 error = ENOBUFS; 266 break; 267 } 268 tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1; 269 sbappend(&so->so_snd, m); 270 tp->t_force = 1; 271 error = tcp_output(tp); 272 tp->t_force = 0; 273 break; 274 275 case PRU_SOCKADDR: 276 in_setsockaddr(inp, nam); 277 break; 278 279 case PRU_PEERADDR: 280 in_setpeeraddr(inp, nam); 281 break; 282 283 /* 284 * TCP slow timer went off; going through this 285 * routine for tracing's sake. 286 */ 287 case PRU_SLOWTIMO: 288 tp = tcp_timers(tp, (int)nam); 289 req |= (int)nam << 8; /* for debug's sake */ 290 break; 291 292 default: 293 panic("tcp_usrreq"); 294 } 295 if (tp && (so->so_options & SO_DEBUG)) 296 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 297 splx(s); 298 return (error); 299 } 300 301 int tcp_sendspace = 1024*4; 302 int tcp_recvspace = 1024*4; 303 /* 304 * Attach TCP protocol to socket, allocating 305 * internet protocol control block, tcp control block, 306 * bufer space, and entering LISTEN state if to accept connections. 307 */ 308 tcp_attach(so) 309 struct socket *so; 310 { 311 register struct tcpcb *tp; 312 struct inpcb *inp; 313 int error; 314 315 error = soreserve(so, tcp_sendspace, tcp_recvspace); 316 if (error) 317 return (error); 318 error = in_pcballoc(so, &tcb); 319 if (error) 320 return (error); 321 inp = sotoinpcb(so); 322 tp = tcp_newtcpcb(inp); 323 if (tp == 0) { 324 int nofd = so->so_state & SS_NOFDREF; /* XXX */ 325 326 so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */ 327 in_pcbdetach(inp); 328 so->so_state |= nofd; 329 return (ENOBUFS); 330 } 331 tp->t_state = TCPS_CLOSED; 332 return (0); 333 } 334 335 /* 336 * Initiate (or continue) disconnect. 337 * If embryonic state, just send reset (once). 338 * If in ``let data drain'' option and linger null, just drop. 339 * Otherwise (hard), mark socket disconnecting and drop 340 * current input data; switch states based on user close, and 341 * send segment to peer (with FIN). 342 */ 343 struct tcpcb * 344 tcp_disconnect(tp) 345 register struct tcpcb *tp; 346 { 347 struct socket *so = tp->t_inpcb->inp_socket; 348 349 if (tp->t_state < TCPS_ESTABLISHED) 350 tp = tcp_close(tp); 351 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 352 tp = tcp_drop(tp, 0); 353 else { 354 soisdisconnecting(so); 355 sbflush(&so->so_rcv); 356 tp = tcp_usrclosed(tp); 357 if (tp) 358 (void) tcp_output(tp); 359 } 360 return (tp); 361 } 362 363 /* 364 * User issued close, and wish to trail through shutdown states: 365 * if never received SYN, just forget it. If got a SYN from peer, 366 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 367 * If already got a FIN from peer, then almost done; go to LAST_ACK 368 * state. In all other cases, have already sent FIN to peer (e.g. 369 * after PRU_SHUTDOWN), and just have to play tedious game waiting 370 * for peer to send FIN or not respond to keep-alives, etc. 371 * We can let the user exit from the close as soon as the FIN is acked. 372 */ 373 struct tcpcb * 374 tcp_usrclosed(tp) 375 register struct tcpcb *tp; 376 { 377 378 switch (tp->t_state) { 379 380 case TCPS_CLOSED: 381 case TCPS_LISTEN: 382 case TCPS_SYN_SENT: 383 tp->t_state = TCPS_CLOSED; 384 tp = tcp_close(tp); 385 break; 386 387 case TCPS_SYN_RECEIVED: 388 case TCPS_ESTABLISHED: 389 tp->t_state = TCPS_FIN_WAIT_1; 390 break; 391 392 case TCPS_CLOSE_WAIT: 393 tp->t_state = TCPS_LAST_ACK; 394 break; 395 } 396 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 397 soisdisconnected(tp->t_inpcb->inp_socket); 398 return (tp); 399 } 400