1 /* tcp_usrreq.c 1.54 82/03/29 */ 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 "../net/in.h" 10 #include "../net/route.h" 11 #include "../net/in_pcb.h" 12 #include "../net/in_systm.h" 13 #include "../net/if.h" 14 #include "../net/ip.h" 15 #include "../net/ip_var.h" 16 #include "../net/tcp.h" 17 #include "../net/tcp_fsm.h" 18 #include "../net/tcp_seq.h" 19 #include "../net/tcp_timer.h" 20 #include "../net/tcp_var.h" 21 #include "../net/tcpip.h" 22 #include "../net/tcp_debug.h" 23 #include "../errno.h" 24 25 /* 26 * TCP protocol interface to socket abstraction. 27 */ 28 extern char *tcpstates[]; 29 struct tcpcb *tcp_newtcpcb(); 30 31 /* 32 * Process a TCP user request for TCP tb. If this is a send request 33 * then m is the mbuf chain of send data. If this is a timer expiration 34 * (called from the software clock routine), then timertype tells which timer. 35 */ 36 tcp_usrreq(so, req, m, addr) 37 struct socket *so; 38 int req; 39 struct mbuf *m; 40 caddr_t addr; 41 { 42 register struct inpcb *inp = sotoinpcb(so); 43 register struct tcpcb *tp; 44 int s = splnet(); 45 int error = 0; 46 int ostate; 47 COUNT(TCP_USRREQ); 48 49 /* 50 * When a TCP is attached to a socket, then there will be 51 * a (struct inpcb) pointed at by the socket, and this 52 * structure will point at a subsidary (struct tcpcb). 53 * The normal sequence of events is: 54 * PRU_ATTACH creating these structures 55 * PRU_CONNECT connecting to a remote peer 56 * (PRU_SEND|PRU_RCVD)* exchanging data 57 * PRU_DISCONNECT disconnecting from remote peer 58 * PRU_DETACH deleting the structures 59 * With the operations from PRU_CONNECT through PRU_DISCONNECT 60 * possible repeated several times. 61 * 62 * MULTIPLE CONNECTS ARE NOT YET IMPLEMENTED. 63 */ 64 if (inp == 0 && req != PRU_ATTACH) { 65 splx(s); 66 return (EINVAL); /* XXX */ 67 } 68 if (inp) { 69 tp = intotcpcb(inp); 70 #ifdef KPROF 71 tcp_acounts[tp->t_state][req]++; 72 #endif 73 ostate = tp->t_state; 74 } 75 switch (req) { 76 77 /* 78 * TCP attaches to socket via PRU_ATTACH, reserving space, 79 * and internet and TCP control blocks. 80 * If the socket is to receive connections, 81 * then the LISTEN state is entered. 82 */ 83 case PRU_ATTACH: 84 if (inp) { 85 error = EISCONN; 86 break; 87 } 88 error = tcp_attach(so, (struct sockaddr *)addr); 89 if (error) 90 break; 91 if ((so->so_options & SO_DONTLINGER) == 0) 92 so->so_linger = TCP_LINGERTIME; 93 tp = sototcpcb(so); 94 break; 95 96 /* 97 * PRU_DETACH detaches the TCP protocol from the socket. 98 * If the protocol state is non-embryonic, then can't 99 * do this directly: have to initiate a PRU_DISCONNECT, 100 * which may finish later; embryonic TCB's can just 101 * be discarded here. 102 */ 103 case PRU_DETACH: 104 if (tp->t_state > TCPS_LISTEN) 105 tcp_disconnect(tp); 106 else { 107 tcp_close(tp); 108 tp = 0; 109 } 110 break; 111 112 /* 113 * Initiate connection to peer. 114 * Create a template for use in transmissions on this connection. 115 * Enter SYN_SENT state, and mark socket as connecting. 116 * Start keep-alive timer, and seed output sequence space. 117 * Send initial segment on connection. 118 */ 119 case PRU_CONNECT: 120 error = in_pcbconnect(inp, (struct sockaddr_in *)addr); 121 if (error) 122 break; 123 tp->t_template = tcp_template(tp); 124 if (tp->t_template == 0) { 125 in_pcbdisconnect(inp); 126 error = ENOBUFS; 127 break; 128 } 129 soisconnecting(so); 130 tp->t_state = TCPS_SYN_SENT; 131 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 132 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 133 tcp_sendseqinit(tp); 134 (void) tcp_output(tp); 135 break; 136 137 /* 138 * Initiate disconnect from peer. 139 * If connection never passed embryonic stage, just drop; 140 * else if don't need to let data drain, then can just drop anyways, 141 * else have to begin TCP shutdown process: mark socket disconnecting, 142 * drain unread data, state switch to reflect user close, and 143 * send segment (e.g. FIN) to peer. Socket will be really disconnected 144 * when peer sends FIN and acks ours. 145 * 146 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 147 */ 148 case PRU_DISCONNECT: 149 tcp_disconnect(tp); 150 break; 151 152 /* 153 * Accept a connection. Essentially all the work is 154 * done at higher levels; just return the address 155 * of the peer, storing through addr. 156 */ 157 case PRU_ACCEPT: { 158 struct sockaddr_in *sin = (struct sockaddr_in *)addr; 159 160 if (sin) { 161 bzero((caddr_t)sin, sizeof (*sin)); 162 sin->sin_family = AF_INET; 163 sin->sin_port = inp->inp_fport; 164 sin->sin_addr = inp->inp_faddr; 165 } 166 } 167 break; 168 169 /* 170 * Mark the connection as being incapable of further output. 171 */ 172 case PRU_SHUTDOWN: 173 socantsendmore(so); 174 tcp_usrclosed(tp); 175 (void) tcp_output(tp); 176 break; 177 178 /* 179 * After a receive, possibly send window update to peer. 180 */ 181 case PRU_RCVD: 182 (void) tcp_output(tp); 183 break; 184 185 /* 186 * Do a send by putting data in output queue and updating urgent 187 * marker if URG set. Possibly send more data. 188 */ 189 case PRU_SEND: 190 sbappend(&so->so_snd, m); 191 /* 192 if (tp->t_flags & TF_PUSH) 193 tp->snd_end = tp->snd_una + so->so_snd.sb_cc; 194 */ 195 (void) tcp_output(tp); 196 break; 197 198 /* 199 * Abort the TCP. 200 */ 201 case PRU_ABORT: 202 tcp_drop(tp, ECONNABORTED); 203 break; 204 205 /* SOME AS YET UNIMPLEMENTED HOOKS */ 206 case PRU_CONTROL: 207 error = EOPNOTSUPP; 208 break; 209 210 case PRU_SENSE: 211 error = EOPNOTSUPP; 212 break; 213 /* END UNIMPLEMENTED HOOKS */ 214 215 case PRU_RCVOOB: 216 if (so->so_oobmark == 0 && 217 (so->so_state & SS_RCVATMARK) == 0) { 218 error = EINVAL; 219 break; 220 } 221 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 222 error = EWOULDBLOCK; 223 break; 224 } 225 *mtod(m, caddr_t) = tp->t_iobc; 226 break; 227 228 case PRU_SENDOOB: 229 #ifdef TCPTRUEOOB 230 if (tp->t_flags & TF_DOOOB) { 231 tp->t_oobseq++; 232 tp->t_oobc = *mtod(m, caddr_t); 233 tp->t_oobmark = tp->snd_una + so->so_snd.sb_cc; 234 printf("sendoob seq now %x oobc %x\n", tp->t_oobseq, tp->t_oobc); 235 tp->t_oobflags |= TCPOOB_NEEDACK; 236 (void) tcp_output(tp); 237 } 238 #endif 239 if (sbspace(&so->so_snd) < -512) { 240 error = ENOBUFS; 241 break; 242 } 243 tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1; 244 sbappend(&so->so_snd, m); 245 /* 246 if (tp->t_flags & TF_PUSH) 247 tp->snd_end = tp->snd_una + so->so_snd.sb_cc; 248 */ 249 tp->t_force = 1; 250 (void) tcp_output(tp); 251 tp->t_force = 0; 252 break; 253 254 /* 255 * TCP slow timer went off; going through this 256 * routine for tracing's sake. 257 */ 258 case PRU_SLOWTIMO: 259 tcp_timers(tp, (int)addr); 260 req |= (int)addr << 8; /* for debug's sake */ 261 break; 262 263 default: 264 panic("tcp_usrreq"); 265 } 266 if (tp && (so->so_options & SO_DEBUG)) 267 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 268 splx(s); 269 return (error); 270 } 271 272 int tcp_sendspace = 1024*2; 273 int tcp_recvspace = 1024*3; 274 /* 275 * Attach TCP protocol to socket, allocating 276 * internet protocol control block, tcp control block, 277 * bufer space, and entering LISTEN state if to accept connections. 278 */ 279 tcp_attach(so, sa) 280 struct socket *so; 281 struct sockaddr *sa; 282 { 283 register struct tcpcb *tp; 284 struct inpcb *inp; 285 int error; 286 287 error = in_pcbattach(so, &tcb, 288 tcp_sendspace, tcp_recvspace, (struct sockaddr_in *)sa); 289 if (error) 290 return (error); 291 inp = (struct inpcb *)so->so_pcb; 292 tp = tcp_newtcpcb(inp); 293 if (so->so_options & SO_ACCEPTCONN) { 294 if (tp == 0) { 295 in_pcbdetach(inp); 296 return (ENOBUFS); 297 } 298 tp->t_state = TCPS_LISTEN; 299 } else 300 tp->t_state = TCPS_CLOSED; 301 return (0); 302 } 303 304 /* 305 * Initiate (or continue) disconnect. 306 * If embryonic state, just send reset (once). 307 * If not in ``let data drain'' option, just drop. 308 * Otherwise (hard), mark socket disconnecting and drop 309 * current input data; switch states based on user close, and 310 * send segment to peer (with FIN). 311 */ 312 tcp_disconnect(tp) 313 struct tcpcb *tp; 314 { 315 struct socket *so = tp->t_inpcb->inp_socket; 316 317 if (tp->t_state < TCPS_ESTABLISHED) 318 tcp_close(tp); 319 else if (so->so_linger == 0) 320 tcp_drop(tp, 0); 321 else { 322 soisdisconnecting(so); 323 sbflush(&so->so_rcv); 324 tcp_usrclosed(tp); 325 (void) tcp_output(tp); 326 } 327 } 328 329 /* 330 * User issued close, and wish to trail through shutdown states: 331 * if never received SYN, just forget it. If got a SYN from peer, 332 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 333 * If already got a FIN from peer, then almost done; go to LAST_ACK 334 * state. In all other cases, have already sent FIN to peer (e.g. 335 * after PRU_SHUTDOWN), and just have to play tedious game waiting 336 * for peer to send FIN or not respond to keep-alives, etc. 337 * We can let the user exit from the close as soon as the FIN is acked. 338 */ 339 tcp_usrclosed(tp) 340 struct tcpcb *tp; 341 { 342 343 switch (tp->t_state) { 344 345 case TCPS_LISTEN: 346 case TCPS_SYN_SENT: 347 tp->t_state = TCPS_CLOSED; 348 tcp_close(tp); 349 break; 350 351 case TCPS_SYN_RECEIVED: 352 case TCPS_ESTABLISHED: 353 tp->t_state = TCPS_FIN_WAIT_1; 354 break; 355 356 case TCPS_CLOSE_WAIT: 357 tp->t_state = TCPS_LAST_ACK; 358 break; 359 } 360 if (tp->t_state >= TCPS_FIN_WAIT_2) 361 soisdisconnected(tp->t_inpcb->inp_socket); 362 } 363