1 /* tcp_usrreq.c 1.52 82/02/27 */ 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/in_pcb.h" 11 #include "../net/in_systm.h" 12 #include "../net/if.h" 13 #include "../net/ip.h" 14 #include "../net/ip_var.h" 15 #include "../net/tcp.h" 16 #include "../net/tcp_fsm.h" 17 #include "../net/tcp_seq.h" 18 #include "../net/tcp_timer.h" 19 #include "../net/tcp_var.h" 20 #include "../net/tcpip.h" 21 #include "../net/tcp_debug.h" 22 #include "../errno.h" 23 24 /* 25 * TCP protocol interface to socket abstraction. 26 */ 27 extern char *tcpstates[]; 28 struct tcpcb *tcp_newtcpcb(); 29 30 /* 31 * Process a TCP user request for TCP tb. If this is a send request 32 * then m is the mbuf chain of send data. If this is a timer expiration 33 * (called from the software clock routine), then timertype tells which timer. 34 */ 35 tcp_usrreq(so, req, m, addr) 36 struct socket *so; 37 int req; 38 struct mbuf *m; 39 caddr_t addr; 40 { 41 register struct inpcb *inp = sotoinpcb(so); 42 register struct tcpcb *tp; 43 int s = splnet(); 44 int error = 0; 45 int ostate; 46 COUNT(TCP_USRREQ); 47 48 /* 49 * When a TCP is attached to a socket, then there will be 50 * a (struct inpcb) pointed at by the socket, and this 51 * structure will point at a subsidary (struct tcpcb). 52 * The normal sequence of events is: 53 * PRU_ATTACH creating these structures 54 * PRU_CONNECT connecting to a remote peer 55 * (PRU_SEND|PRU_RCVD)* exchanging data 56 * PRU_DISCONNECT disconnecting from remote peer 57 * PRU_DETACH deleting the structures 58 * With the operations from PRU_CONNECT through PRU_DISCONNECT 59 * possible repeated several times. 60 * 61 * MULTIPLE CONNECTS ARE NOT YET IMPLEMENTED. 62 */ 63 if (inp == 0 && req != PRU_ATTACH) { 64 splx(s); 65 return (EINVAL); /* XXX */ 66 } 67 if (inp) { 68 tp = intotcpcb(inp); 69 #ifdef KPROF 70 tcp_acounts[tp->t_state][req]++; 71 #endif 72 ostate = tp->t_state; 73 } 74 switch (req) { 75 76 /* 77 * TCP attaches to socket via PRU_ATTACH, reserving space, 78 * and internet and TCP control blocks. 79 * If the socket is to receive connections, 80 * then the LISTEN state is entered. 81 */ 82 case PRU_ATTACH: 83 if (inp) { 84 error = EISCONN; 85 break; 86 } 87 error = tcp_attach(so, (struct sockaddr *)addr); 88 if (error) 89 break; 90 if ((so->so_options & SO_DONTLINGER) == 0) 91 so->so_linger = TCP_LINGERTIME; 92 tp = sototcpcb(so); 93 break; 94 95 /* 96 * PRU_DETACH detaches the TCP protocol from the socket. 97 * If the protocol state is non-embryonic, then can't 98 * do this directly: have to initiate a PRU_DISCONNECT, 99 * which may finish later; embryonic TCB's can just 100 * be discarded here. 101 */ 102 case PRU_DETACH: 103 if (tp->t_state > TCPS_LISTEN) 104 tcp_disconnect(tp); 105 else { 106 tcp_close(tp); 107 tp = 0; 108 } 109 break; 110 111 /* 112 * Initiate connection to peer. 113 * Create a template for use in transmissions on this connection. 114 * Enter SYN_SENT state, and mark socket as connecting. 115 * Start keep-alive timer, and seed output sequence space. 116 * Send initial segment on connection. 117 */ 118 case PRU_CONNECT: 119 error = in_pcbconnect(inp, (struct sockaddr_in *)addr); 120 if (error) 121 break; 122 tp->t_template = tcp_template(tp); 123 if (tp->t_template == 0) { 124 in_pcbdisconnect(inp); 125 error = ENOBUFS; 126 break; 127 } 128 soisconnecting(so); 129 tp->t_state = TCPS_SYN_SENT; 130 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 131 tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2; 132 tcp_sendseqinit(tp); 133 (void) tcp_output(tp); 134 break; 135 136 /* 137 * Initiate disconnect from peer. 138 * If connection never passed embryonic stage, just drop; 139 * else if don't need to let data drain, then can just drop anyways, 140 * else have to begin TCP shutdown process: mark socket disconnecting, 141 * drain unread data, state switch to reflect user close, and 142 * send segment (e.g. FIN) to peer. Socket will be really disconnected 143 * when peer sends FIN and acks ours. 144 * 145 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB. 146 */ 147 case PRU_DISCONNECT: 148 tcp_disconnect(tp); 149 break; 150 151 /* 152 * Accept a connection. Essentially all the work is 153 * done at higher levels; just return the address 154 * of the peer, storing through addr. 155 */ 156 case PRU_ACCEPT: 157 break; 158 159 /* 160 * Mark the connection as being incapable of further output. 161 */ 162 case PRU_SHUTDOWN: 163 socantsendmore(so); 164 tcp_usrclosed(tp); 165 (void) tcp_output(tp); 166 break; 167 168 /* 169 * After a receive, possibly send window update to peer. 170 */ 171 case PRU_RCVD: 172 (void) tcp_output(tp); 173 break; 174 175 /* 176 * Do a send by putting data in output queue and updating urgent 177 * marker if URG set. Possibly send more data. 178 */ 179 case PRU_SEND: 180 sbappend(&so->so_snd, m); 181 /* 182 if (tp->t_flags & TF_PUSH) 183 tp->snd_end = tp->snd_una + so->so_snd.sb_cc; 184 */ 185 (void) tcp_output(tp); 186 break; 187 188 /* 189 * Abort the TCP. 190 */ 191 case PRU_ABORT: 192 tcp_drop(tp, ECONNABORTED); 193 break; 194 195 /* SOME AS YET UNIMPLEMENTED HOOKS */ 196 case PRU_CONTROL: 197 error = EOPNOTSUPP; 198 break; 199 200 case PRU_SENSE: 201 error = EOPNOTSUPP; 202 break; 203 /* END UNIMPLEMENTED HOOKS */ 204 205 case PRU_RCVOOB: 206 if (so->so_oobmark == 0 && 207 (so->so_state & SS_RCVATMARK) == 0) { 208 error = EINVAL; 209 break; 210 } 211 if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) { 212 error = EWOULDBLOCK; 213 break; 214 } 215 *mtod(m, caddr_t) = tp->t_iobc; 216 break; 217 218 case PRU_SENDOOB: 219 #ifdef TCPTRUEOOB 220 if (tp->t_flags & TF_DOOOB) { 221 tp->t_oobseq++; 222 tp->t_oobc = *mtod(m, caddr_t); 223 tp->t_oobmark = tp->snd_una + so->so_snd.sb_cc; 224 printf("sendoob seq now %x oobc %x\n", tp->t_oobseq, tp->t_oobc); 225 tp->t_oobflags |= TCPOOB_NEEDACK; 226 (void) tcp_output(tp); 227 } 228 #endif 229 if (sbspace(&so->so_snd) < -512) { 230 error = ENOBUFS; 231 break; 232 } 233 tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1; 234 sbappend(&so->so_snd, m); 235 /* 236 if (tp->t_flags & TF_PUSH) 237 tp->snd_end = tp->snd_una + so->so_snd.sb_cc; 238 */ 239 tp->t_force = 1; 240 (void) tcp_output(tp); 241 tp->t_force = 0; 242 break; 243 244 /* 245 * TCP slow timer went off; going through this 246 * routine for tracing's sake. 247 */ 248 case PRU_SLOWTIMO: 249 tcp_timers(tp, (int)addr); 250 req |= (int)addr << 8; /* for debug's sake */ 251 break; 252 253 default: 254 panic("tcp_usrreq"); 255 } 256 if (tp && (so->so_options & SO_DEBUG)) 257 tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req); 258 splx(s); 259 return (error); 260 } 261 262 int tcp_sendspace = 1024*2; 263 int tcp_recvspace = 1024*3; 264 /* 265 * Attach TCP protocol to socket, allocating 266 * internet protocol control block, tcp control block, 267 * bufer space, and entering LISTEN state if to accept connections. 268 */ 269 tcp_attach(so, sa) 270 struct socket *so; 271 struct sockaddr *sa; 272 { 273 register struct tcpcb *tp; 274 struct inpcb *inp; 275 int error; 276 277 error = in_pcbattach(so, &tcb, 278 tcp_sendspace, tcp_recvspace, (struct sockaddr_in *)sa); 279 if (error) 280 return (error); 281 inp = (struct inpcb *)so->so_pcb; 282 tp = tcp_newtcpcb(inp); 283 if (so->so_options & SO_ACCEPTCONN) { 284 if (tp == 0) { 285 in_pcbdetach(inp); 286 return (ENOBUFS); 287 } 288 tp->t_state = TCPS_LISTEN; 289 } else 290 tp->t_state = TCPS_CLOSED; 291 return (0); 292 } 293 294 /* 295 * Initiate (or continue) disconnect. 296 * If embryonic state, just send reset (once). 297 * If not in ``let data drain'' option, just drop. 298 * Otherwise (hard), mark socket disconnecting and drop 299 * current input data; switch states based on user close, and 300 * send segment to peer (with FIN). 301 */ 302 tcp_disconnect(tp) 303 struct tcpcb *tp; 304 { 305 struct socket *so = tp->t_inpcb->inp_socket; 306 307 if (tp->t_state < TCPS_ESTABLISHED) 308 tcp_close(tp); 309 else if (so->so_linger == 0) 310 tcp_drop(tp, 0); 311 else { 312 soisdisconnecting(so); 313 sbflush(&so->so_rcv); 314 tcp_usrclosed(tp); 315 (void) tcp_output(tp); 316 } 317 } 318 319 /* 320 * User issued close, and wish to trail through shutdown states: 321 * if never received SYN, just forget it. If got a SYN from peer, 322 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN. 323 * If already got a FIN from peer, then almost done; go to LAST_ACK 324 * state. In all other cases, have already sent FIN to peer (e.g. 325 * after PRU_SHUTDOWN), and just have to play tedious game waiting 326 * for peer to send FIN or not respond to keep-alives, etc. 327 * We can let the user exit from the close as soon as the FIN is acked. 328 */ 329 tcp_usrclosed(tp) 330 struct tcpcb *tp; 331 { 332 333 switch (tp->t_state) { 334 335 case TCPS_LISTEN: 336 case TCPS_SYN_SENT: 337 tp->t_state = TCPS_CLOSED; 338 tcp_close(tp); 339 break; 340 341 case TCPS_SYN_RECEIVED: 342 case TCPS_ESTABLISHED: 343 tp->t_state = TCPS_FIN_WAIT_1; 344 break; 345 346 case TCPS_CLOSE_WAIT: 347 tp->t_state = TCPS_LAST_ACK; 348 break; 349 } 350 if (tp->t_state >= TCPS_FIN_WAIT_2) 351 soisdisconnected(tp->t_inpcb->inp_socket); 352 } 353