1 /* tcp_usrreq.c 6.1 83/07/29 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/mbuf.h" 6 #include "../h/socket.h" 7 #include "../h/socketvar.h" 8 #include "../h/protosw.h" 9 #include "../h/errno.h" 10 11 #include "../net/if.h" 12 #include "../net/route.h" 13 14 #include "../netinet/in.h" 15 #include "../netinet/in_pcb.h" 16 #include "../netinet/in_systm.h" 17 #include "../netinet/ip.h" 18 #include "../netinet/ip_var.h" 19 #include "../netinet/tcp.h" 20 #include "../netinet/tcp_fsm.h" 21 #include "../netinet/tcp_seq.h" 22 #include "../netinet/tcp_timer.h" 23 #include "../netinet/tcp_var.h" 24 #include "../netinet/tcpip.h" 25 #include "../netinet/tcp_debug.h" 26 27 /* 28 * TCP protocol interface to socket abstraction. 29 */ 30 extern char *tcpstates[]; 31 struct tcpcb *tcp_newtcpcb(); 32 int tcpsenderrors; 33 34 /* 35 * Process a TCP user request for TCP tb. If this is a send request 36 * then m is the mbuf chain of send data. If this is a timer expiration 37 * (called from the software clock routine), then timertype tells which timer. 38 */ 39 /*ARGSUSED*/ 40 tcp_usrreq(so, req, m, nam, rights) 41 struct socket *so; 42 int req; 43 struct mbuf *m, *nam, *rights; 44 { 45 register struct inpcb *inp = sotoinpcb(so); 46 register struct tcpcb *tp; 47 int s = splnet(); 48 int error = 0; 49 int ostate; 50 51 if (rights && rights->m_len) { 52 splx(s); 53 return (EINVAL); 54 } 55 /* 56 * When a TCP is attached to a socket, then there will be 57 * a (struct inpcb) pointed at by the socket, and this 58 * structure will point at a subsidary (struct tcpcb). 59 */ 60 if (inp == 0 && req != PRU_ATTACH) { 61 splx(s); 62 return (EINVAL); /* XXX */ 63 } 64 if (inp) { 65 tp = intotcpcb(inp); 66 /* WHAT IF TP IS 0? */ 67 #ifdef KPROF 68 tcp_acounts[tp->t_state][req]++; 69 #endif 70 ostate = tp->t_state; 71 } else 72 ostate = 0; 73 switch (req) { 74 75 /* 76 * TCP attaches to socket via PRU_ATTACH, reserving space, 77 * and an internet control block. 78 */ 79 case PRU_ATTACH: 80 if (inp) { 81 error = EISCONN; 82 break; 83 } 84 error = tcp_attach(so); 85 if (error) 86 break; 87 if ((so->so_options & SO_LINGER) && so->so_linger == 0) 88 so->so_linger = TCP_LINGERTIME; 89 tp = sototcpcb(so); 90 break; 91 92 /* 93 * PRU_DETACH detaches the TCP protocol from the socket. 94 * If the protocol state is non-embryonic, then can't 95 * do this directly: have to initiate a PRU_DISCONNECT, 96 * which may finish later; embryonic TCB's can just 97 * be discarded here. 98 */ 99 case PRU_DETACH: 100 if (tp->t_state > TCPS_LISTEN) 101 tp = tcp_disconnect(tp); 102 else 103 tp = tcp_close(tp); 104 break; 105 106 /* 107 * Give the socket an address. 108 */ 109 case PRU_BIND: 110 error = in_pcbbind(inp, nam); 111 if (error) 112 break; 113 break; 114 115 /* 116 * Prepare to accept connections. 117 */ 118 case PRU_LISTEN: 119 if (inp->inp_lport == 0) 120 error = in_pcbbind(inp, (struct mbuf *)0); 121 if (error == 0) 122 tp->t_state = TCPS_LISTEN; 123 break; 124 125 /* 126 * Initiate connection to peer. 127 * Create a template for use in transmissions on this connection. 128 * Enter SYN_SENT state, and mark socket as connecting. 129 * Start keep-alive timer, and seed output sequence space. 130 * Send initial segment on connection. 131 */ 132 case PRU_CONNECT: 133 if (inp->inp_lport == 0) { 134 error = in_pcbbind(inp, (struct mbuf *)0); 135 if (error) 136 break; 137 } 138 error = in_pcbconnect(inp, nam); 139 if (error) 140 break; 141 tp->t_template = tcp_template(tp); 142 if (tp->t_template == 0) { 143 in_pcbdisconnect(inp); 144 error = ENOBUFS; 145 break; 146 } 147 soisconnecting(so); 148 tp->t_state = TCPS_SYN_SENT; 149 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 150 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 151 tcp_sendseqinit(tp); 152 error = tcp_output(tp); 153 break; 154 155 /* 156 * Create a TCP connection between two sockets. 157 */ 158 case PRU_CONNECT2: 159 error = EOPNOTSUPP; 160 break; 161 162 /* 163 * Initiate disconnect from peer. 164 * If connection never passed embryonic stage, just drop; 165 * else if don't need to let data drain, then can just drop anyways, 166 * else have to begin TCP shutdown process: mark socket disconnecting, 167 * drain unread data, state switch to reflect user close, and 168 * send segment (e.g. FIN) to peer. Socket will be really disconnected 169 * when peer sends FIN and acks ours. 170 * 171 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 172 */ 173 case PRU_DISCONNECT: 174 tp = tcp_disconnect(tp); 175 break; 176 177 /* 178 * Accept a connection. Essentially all the work is 179 * done at higher levels; just return the address 180 * of the peer, storing through addr. 181 */ 182 case PRU_ACCEPT: { 183 struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *); 184 185 nam->m_len = sizeof (struct sockaddr_in); 186 sin->sin_family = AF_INET; 187 sin->sin_port = inp->inp_fport; 188 sin->sin_addr = inp->inp_faddr; 189 break; 190 } 191 192 /* 193 * Mark the connection as being incapable of further output. 194 */ 195 case PRU_SHUTDOWN: 196 socantsendmore(so); 197 tp = tcp_usrclosed(tp); 198 if (tp) 199 error = tcp_output(tp); 200 break; 201 202 /* 203 * After a receive, possibly send window update to peer. 204 */ 205 case PRU_RCVD: 206 (void) tcp_output(tp); 207 break; 208 209 /* 210 * Do a send by putting data in output queue and updating urgent 211 * marker if URG set. Possibly send more data. 212 */ 213 case PRU_SEND: 214 sbappend(&so->so_snd, m); 215 #ifdef notdef 216 if (tp->t_flags & TF_PUSH) 217 tp->snd_end = tp->snd_una + so->so_snd.sb_cc; 218 #endif 219 error = tcp_output(tp); 220 if (error) { /* XXX fix to use other path */ 221 if (error == ENOBUFS) /* XXX */ 222 error = 0; /* XXX */ 223 tcpsenderrors++; 224 } 225 break; 226 227 /* 228 * Abort the TCP. 229 */ 230 case PRU_ABORT: 231 tp = tcp_drop(tp, ECONNABORTED); 232 break; 233 234 /* SOME AS YET UNIMPLEMENTED HOOKS */ 235 case PRU_CONTROL: 236 error = EOPNOTSUPP; 237 break; 238 239 case PRU_SENSE: 240 error = EOPNOTSUPP; 241 break; 242 /* END UNIMPLEMENTED HOOKS */ 243 244 case PRU_RCVOOB: 245 if (so->so_oobmark == 0 && 246 (so->so_state & SS_RCVATMARK) == 0) { 247 error = EINVAL; 248 break; 249 } 250 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 251 error = EWOULDBLOCK; 252 break; 253 } 254 m->m_len = 1; 255 *mtod(m, caddr_t) = tp->t_iobc; 256 break; 257 258 case PRU_SENDOOB: 259 if (sbspace(&so->so_snd) < -512) { 260 m_freem(m); 261 error = ENOBUFS; 262 break; 263 } 264 tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1; 265 sbappend(&so->so_snd, m); 266 tp->t_force = 1; 267 error = tcp_output(tp); 268 tp->t_force = 0; 269 break; 270 271 case PRU_SOCKADDR: 272 in_setsockaddr(inp, nam); 273 break; 274 275 case PRU_PEERADDR: 276 in_setpeeraddr(inp, nam); 277 break; 278 279 /* 280 * TCP slow timer went off; going through this 281 * routine for tracing's sake. 282 */ 283 case PRU_SLOWTIMO: 284 tp = tcp_timers(tp, (int)nam); 285 req |= (int)nam << 8; /* for debug's sake */ 286 break; 287 288 default: 289 panic("tcp_usrreq"); 290 } 291 if (tp && (so->so_options & SO_DEBUG)) 292 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 293 splx(s); 294 return (error); 295 } 296 297 int tcp_sendspace = 1024*2; 298 int tcp_recvspace = 1024*2; 299 /* 300 * Attach TCP protocol to socket, allocating 301 * internet protocol control block, tcp control block, 302 * bufer space, and entering LISTEN state if to accept connections. 303 */ 304 tcp_attach(so) 305 struct socket *so; 306 { 307 register struct tcpcb *tp; 308 struct inpcb *inp; 309 int error; 310 311 error = soreserve(so, tcp_sendspace, tcp_recvspace); 312 if (error) 313 goto bad; 314 error = in_pcballoc(so, &tcb); 315 if (error) 316 goto bad; 317 inp = sotoinpcb(so); 318 tp = tcp_newtcpcb(inp); 319 if (tp == 0) { 320 error = ENOBUFS; 321 goto bad2; 322 } 323 tp->t_state = TCPS_CLOSED; 324 return (0); 325 bad2: 326 in_pcbdetach(inp); 327 bad: 328 return (error); 329 } 330 331 /* 332 * Initiate (or continue) disconnect. 333 * If embryonic state, just send reset (once). 334 * If in ``let data drain'' option and linger null, just drop. 335 * Otherwise (hard), mark socket disconnecting and drop 336 * current input data; switch states based on user close, and 337 * send segment to peer (with FIN). 338 */ 339 struct tcpcb * 340 tcp_disconnect(tp) 341 register struct tcpcb *tp; 342 { 343 struct socket *so = tp->t_inpcb->inp_socket; 344 345 if (tp->t_state < TCPS_ESTABLISHED) 346 tp = tcp_close(tp); 347 else if ((so->so_options & SO_LINGER) && so->so_linger == 0) 348 tp = tcp_drop(tp, 0); 349 else { 350 soisdisconnecting(so); 351 sbflush(&so->so_rcv); 352 tp = tcp_usrclosed(tp); 353 if (tp) 354 (void) tcp_output(tp); 355 } 356 return (tp); 357 } 358 359 /* 360 * User issued close, and wish to trail through shutdown states: 361 * if never received SYN, just forget it. If got a SYN from peer, 362 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 363 * If already got a FIN from peer, then almost done; go to LAST_ACK 364 * state. In all other cases, have already sent FIN to peer (e.g. 365 * after PRU_SHUTDOWN), and just have to play tedious game waiting 366 * for peer to send FIN or not respond to keep-alives, etc. 367 * We can let the user exit from the close as soon as the FIN is acked. 368 */ 369 struct tcpcb * 370 tcp_usrclosed(tp) 371 register struct tcpcb *tp; 372 { 373 374 switch (tp->t_state) { 375 376 case TCPS_CLOSED: 377 case TCPS_LISTEN: 378 case TCPS_SYN_SENT: 379 tp->t_state = TCPS_CLOSED; 380 tp = tcp_close(tp); 381 break; 382 383 case TCPS_SYN_RECEIVED: 384 case TCPS_ESTABLISHED: 385 tp->t_state = TCPS_FIN_WAIT_1; 386 break; 387 388 case TCPS_CLOSE_WAIT: 389 tp->t_state = TCPS_LAST_ACK; 390 break; 391 } 392 if (tp && tp->t_state >= TCPS_FIN_WAIT_2) 393 soisdisconnected(tp->t_inpcb->inp_socket); 394 return (tp); 395 } 396