[unix-history] / usr / src / sys / netinet / tcp_usrreq.c

/* tcp_usrreq.c 1.54 82/03/29 */

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mbuf.h"
#include "../h/socket.h"
#include "../h/socketvar.h"
#include "../h/protosw.h"
#include "../net/in.h"
#include "../net/route.h"
#include "../net/in_pcb.h"
#include "../net/in_systm.h"
#include "../net/if.h"
#include "../net/ip.h"
#include "../net/ip_var.h"
#include "../net/tcp.h"
#include "../net/tcp_fsm.h"
#include "../net/tcp_seq.h"
#include "../net/tcp_timer.h"
#include "../net/tcp_var.h"
#include "../net/tcpip.h"
#include "../net/tcp_debug.h"
#include "../errno.h"

/*
 * TCP protocol interface to socket abstraction.
 */
extern	char *tcpstates[];
struct	tcpcb *tcp_newtcpcb();

/*
 * Process a TCP user request for TCP tb.  If this is a send request
 * then m is the mbuf chain of send data.  If this is a timer expiration
 * (called from the software clock routine), then timertype tells which timer.
 */
tcp_usrreq(so, req, m, addr)
	struct socket *so;
	int req;
	struct mbuf *m;
	caddr_t addr;
{
	register struct inpcb *inp = sotoinpcb(so);
	register struct tcpcb *tp;
	int s = splnet();
	int error = 0;
	int ostate;
COUNT(TCP_USRREQ);

	/*
	 * When a TCP is attached to a socket, then there will be
	 * a (struct inpcb) pointed at by the socket, and this
	 * structure will point at a subsidary (struct tcpcb).
	 * The normal sequence of events is:
	 *	PRU_ATTACH		creating these structures
	 *	PRU_CONNECT		connecting to a remote peer
	 *	(PRU_SEND|PRU_RCVD)*	exchanging data
	 *	PRU_DISCONNECT		disconnecting from remote peer
	 *	PRU_DETACH		deleting the structures
	 * With the operations from PRU_CONNECT through PRU_DISCONNECT
	 * possible repeated several times.
	 *
	 * MULTIPLE CONNECTS ARE NOT YET IMPLEMENTED.
	 */
	if (inp == 0 && req != PRU_ATTACH) {
		splx(s);
		return (EINVAL);		/* XXX */
	}
	if (inp) {
		tp = intotcpcb(inp);
#ifdef KPROF
		tcp_acounts[tp->t_state][req]++;
#endif
		ostate = tp->t_state;
	}
	switch (req) {

	/*
	 * TCP attaches to socket via PRU_ATTACH, reserving space,
	 * and internet and TCP control blocks.
	 * If the socket is to receive connections,
	 * then the LISTEN state is entered.
	 */
	case PRU_ATTACH:
		if (inp) {
			error = EISCONN;
			break;
		}
		error = tcp_attach(so, (struct sockaddr *)addr);
		if (error)
			break;
		if ((so->so_options & SO_DONTLINGER) == 0)
			so->so_linger = TCP_LINGERTIME;
		tp = sototcpcb(so);
		break;

	/*
	 * PRU_DETACH detaches the TCP protocol from the socket.
	 * If the protocol state is non-embryonic, then can't
	 * do this directly: have to initiate a PRU_DISCONNECT,
	 * which may finish later; embryonic TCB's can just
	 * be discarded here.
	 */
	case PRU_DETACH:
		if (tp->t_state > TCPS_LISTEN)
			tcp_disconnect(tp);
		else {
			tcp_close(tp);
			tp = 0;
		}
		break;

	/*
	 * Initiate connection to peer.
	 * Create a template for use in transmissions on this connection.
	 * Enter SYN_SENT state, and mark socket as connecting.
	 * Start keep-alive timer, and seed output sequence space.
	 * Send initial segment on connection.
	 */
	case PRU_CONNECT:
		error = in_pcbconnect(inp, (struct sockaddr_in *)addr);
		if (error)
			break;
		tp->t_template = tcp_template(tp);
		if (tp->t_template == 0) {
			in_pcbdisconnect(inp);
			error = ENOBUFS;
			break;
		}
		soisconnecting(so);
		tp->t_state = TCPS_SYN_SENT;
		tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
		tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
		tcp_sendseqinit(tp);
		(void) tcp_output(tp);
		break;

	/*
	 * Initiate disconnect from peer.
	 * If connection never passed embryonic stage, just drop;
	 * else if don't need to let data drain, then can just drop anyways,
	 * else have to begin TCP shutdown process: mark socket disconnecting,
	 * drain unread data, state switch to reflect user close, and
	 * send segment (e.g. FIN) to peer.  Socket will be really disconnected
	 * when peer sends FIN and acks ours.
	 *
	 * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
	 */
	case PRU_DISCONNECT:
		tcp_disconnect(tp);
		break;

	/*
	 * Accept a connection.  Essentially all the work is
	 * done at higher levels; just return the address
	 * of the peer, storing through addr.
	 */
	case PRU_ACCEPT: {
		struct sockaddr_in *sin = (struct sockaddr_in *)addr;

		if (sin) {
			bzero((caddr_t)sin, sizeof (*sin));
			sin->sin_family = AF_INET;
			sin->sin_port = inp->inp_fport;
			sin->sin_addr = inp->inp_faddr;
		}
		}
		break;

	/*
	 * Mark the connection as being incapable of further output.
	 */
	case PRU_SHUTDOWN:
		socantsendmore(so);
		tcp_usrclosed(tp);
		(void) tcp_output(tp);
		break;

	/*
	 * After a receive, possibly send window update to peer.
	 */
	case PRU_RCVD:
		(void) tcp_output(tp);
		break;

	/*
	 * Do a send by putting data in output queue and updating urgent
	 * marker if URG set.  Possibly send more data.
	 */
	case PRU_SEND:
		sbappend(&so->so_snd, m);
/*
		if (tp->t_flags & TF_PUSH)
			tp->snd_end = tp->snd_una + so->so_snd.sb_cc;
 */
		(void) tcp_output(tp);
		break;

	/*
	 * Abort the TCP.
	 */
	case PRU_ABORT:
		tcp_drop(tp, ECONNABORTED);
		break;

/* SOME AS YET UNIMPLEMENTED HOOKS */
	case PRU_CONTROL:
		error = EOPNOTSUPP;
		break;

	case PRU_SENSE:
		error = EOPNOTSUPP;
		break;
/* END UNIMPLEMENTED HOOKS */

	case PRU_RCVOOB:
		if (so->so_oobmark == 0 &&
		    (so->so_state & SS_RCVATMARK) == 0) {
			error = EINVAL;
			break;
		}
		if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
			error = EWOULDBLOCK;
			break;
		}
		*mtod(m, caddr_t) = tp->t_iobc;
		break;

	case PRU_SENDOOB:
#ifdef TCPTRUEOOB
		if (tp->t_flags & TF_DOOOB) {
			tp->t_oobseq++;
			tp->t_oobc = *mtod(m, caddr_t);
			tp->t_oobmark = tp->snd_una + so->so_snd.sb_cc;
printf("sendoob seq now %x oobc %x\n", tp->t_oobseq, tp->t_oobc);
			tp->t_oobflags |= TCPOOB_NEEDACK;
			(void) tcp_output(tp);
		}
#endif
		if (sbspace(&so->so_snd) < -512) {
			error = ENOBUFS;
			break;
		}
		tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1;
		sbappend(&so->so_snd, m);
/*
		if (tp->t_flags & TF_PUSH)
			tp->snd_end = tp->snd_una + so->so_snd.sb_cc;
 */
		tp->t_force = 1;
		(void) tcp_output(tp);
		tp->t_force = 0;
		break;

	/*
	 * TCP slow timer went off; going through this
	 * routine for tracing's sake.
	 */
	case PRU_SLOWTIMO:
		tcp_timers(tp, (int)addr);
		req |= (int)addr << 8;		/* for debug's sake */
		break;

	default:
		panic("tcp_usrreq");
	}
	if (tp && (so->so_options & SO_DEBUG))
		tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req);
	splx(s);
	return (error);
}

int	tcp_sendspace = 1024*2;
int	tcp_recvspace = 1024*3;
/*
 * Attach TCP protocol to socket, allocating
 * internet protocol control block, tcp control block,
 * bufer space, and entering LISTEN state if to accept connections.
 */
tcp_attach(so, sa)
	struct socket *so;
	struct sockaddr *sa;
{
	register struct tcpcb *tp;
	struct inpcb *inp;
	int error;

	error = in_pcbattach(so, &tcb,
	    tcp_sendspace, tcp_recvspace, (struct sockaddr_in *)sa);
	if (error)
		return (error);
	inp = (struct inpcb *)so->so_pcb;
	tp = tcp_newtcpcb(inp);
	if (so->so_options & SO_ACCEPTCONN) {
		if (tp == 0) {
			in_pcbdetach(inp);
			return (ENOBUFS);
		}
		tp->t_state = TCPS_LISTEN;
	} else
		tp->t_state = TCPS_CLOSED;
	return (0);
}

/*
 * Initiate (or continue) disconnect.
 * If embryonic state, just send reset (once).
 * If not in ``let data drain'' option, just drop.
 * Otherwise (hard), mark socket disconnecting and drop
 * current input data; switch states based on user close, and
 * send segment to peer (with FIN).
 */
tcp_disconnect(tp)
	struct tcpcb *tp;
{
	struct socket *so = tp->t_inpcb->inp_socket;

	if (tp->t_state < TCPS_ESTABLISHED)
		tcp_close(tp);
	else if (so->so_linger == 0)
		tcp_drop(tp, 0);
	else {
		soisdisconnecting(so);
		sbflush(&so->so_rcv);
		tcp_usrclosed(tp);
		(void) tcp_output(tp);
	}
}

/*
 * User issued close, and wish to trail through shutdown states:
 * if never received SYN, just forget it.  If got a SYN from peer,
 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
 * If already got a FIN from peer, then almost done; go to LAST_ACK
 * state.  In all other cases, have already sent FIN to peer (e.g.
 * after PRU_SHUTDOWN), and just have to play tedious game waiting
 * for peer to send FIN or not respond to keep-alives, etc.
 * We can let the user exit from the close as soon as the FIN is acked.
 */
tcp_usrclosed(tp)
	struct tcpcb *tp;
{

	switch (tp->t_state) {

	case TCPS_LISTEN:
	case TCPS_SYN_SENT:
		tp->t_state = TCPS_CLOSED;
		tcp_close(tp);
		break;

	case TCPS_SYN_RECEIVED:
	case TCPS_ESTABLISHED:
		tp->t_state = TCPS_FIN_WAIT_1;
		break;

	case TCPS_CLOSE_WAIT:
		tp->t_state = TCPS_LAST_ACK;
		break;
	}
	if (tp->t_state >= TCPS_FIN_WAIT_2)
		soisdisconnected(tp->t_inpcb->inp_socket);
}
Commit	Line	Data
c124e997	1	/* tcp_usrreq.c 1.54 82/03/29 */
72f24d7d	2
4eb5d593	3	#include "../h/param.h"
72f24d7d	4	#include "../h/systm.h"
dad64fdf BJ	5	#include "../h/mbuf.h"
dad64fdf BJ	6	#include "../h/socket.h"
eee3ab16 BJ	7	#include "../h/socketvar.h"
eee3ab16 BJ	8	#include "../h/protosw.h"
0974b45c	9	#include "../net/in.h"
c124e997	10	#include "../net/route.h"
0974b45c BJ	11	#include "../net/in_pcb.h"
0974b45c BJ	12	#include "../net/in_systm.h"
4ad99bae	13	#include "../net/if.h"
eee3ab16	14	#include "../net/ip.h"
eb44bfb2	15	#include "../net/ip_var.h"
eee3ab16	16	#include "../net/tcp.h"
eee3ab16	17	#include "../net/tcp_fsm.h"
0974b45c BJ	18	#include "../net/tcp_seq.h"
0974b45c BJ	19	#include "../net/tcp_timer.h"
eee3ab16	20	#include "../net/tcp_var.h"
0974b45c	21	#include "../net/tcpip.h"
17b82ed4	22	#include "../net/tcp_debug.h"
f1b2fa5b	23	#include "../errno.h"
eee3ab16	24
290e0b0a BJ	25	/*
	26	* TCP protocol interface to socket abstraction.
	27	*/
	28	extern char *tcpstates[];
4ad99bae	29	struct tcpcb *tcp_newtcpcb();
290e0b0a	30
9c5022e3	31	/*
290e0b0a	32	* Process a TCP user request for TCP tb. If this is a send request
9c5022e3 BJ	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	*/
eee3ab16 BJ	36	tcp_usrreq(so, req, m, addr)
	37	struct socket *so;
	38	int req;
9c5022e3	39	struct mbuf *m;
eee3ab16	40	caddr_t addr;
4eb5d593	41	{
53a5409e	42	register struct inpcb *inp = sotoinpcb(so);
cdad2eb1	43	register struct tcpcb *tp;
72f24d7d	44	int s = splnet();
eee3ab16	45	int error = 0;
17b82ed4	46	int ostate;
72f24d7d BJ	47	COUNT(TCP_USRREQ);
72f24d7d BJ	48
53a5409e	49	/*
290e0b0a BJ	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.
53a5409e	63	*/
0974b45c	64	if (inp == 0 && req != PRU_ATTACH) {
a6503abf	65	splx(s);
290e0b0a	66	return (EINVAL); /* XXX */
a6503abf BJ	67	}
a6503abf BJ	68	if (inp) {
cdad2eb1	69	tp = intotcpcb(inp);
9c5022e3	70	#ifdef KPROF
a6503abf	71	tcp_acounts[tp->t_state][req]++;
9c5022e3	72	#endif
17b82ed4	73	ostate = tp->t_state;
cdad2eb1	74	}
eee3ab16	75	switch (req) {
4eb5d593	76
290e0b0a BJ	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	*/
eee3ab16	83	case PRU_ATTACH:
4ad99bae	84	if (inp) {
eee3ab16	85	error = EISCONN;
cdad2eb1	86	break;
53a5409e	87	}
290e0b0a	88	error = tcp_attach(so, (struct sockaddr *)addr);
a6503abf	89	if (error)
4ad99bae	90	break;
8e65fd66 BJ	91	if ((so->so_options & SO_DONTLINGER) == 0)
8e65fd66 BJ	92	so->so_linger = TCP_LINGERTIME;
290e0b0a	93	tp = sototcpcb(so);
72f24d7d	94	break;
4eb5d593	95
290e0b0a BJ	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	*/
eee3ab16	103	case PRU_DETACH:
290e0b0a BJ	104	if (tp->t_state > TCPS_LISTEN)
	105	tcp_disconnect(tp);
	106	else {
	107	tcp_close(tp);
	108	tp = 0;
	109	}
eee3ab16 BJ	110	break;
eee3ab16 BJ	111
290e0b0a BJ	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	*/
eee3ab16	119	case PRU_CONNECT:
405c9168	120	error = in_pcbconnect(inp, (struct sockaddr_in *)addr);
4ad99bae	121	if (error)
53a5409e	122	break;
b454c3ea	123	tp->t_template = tcp_template(tp);
290e0b0a BJ	124	if (tp->t_template == 0) {
	125	in_pcbdisconnect(inp);
	126	error = ENOBUFS;
	127	break;
	128	}
53a5409e	129	soisconnecting(so);
a6503abf	130	tp->t_state = TCPS_SYN_SENT;
4aed14e3 BJ	131	tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
	132	tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
	133	tcp_sendseqinit(tp);
f1b2fa5b	134	(void) tcp_output(tp);
72f24d7d	135	break;
4eb5d593	136
290e0b0a BJ	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);
4aed14e3 BJ	150	break;
4aed14e3 BJ	151
290e0b0a BJ	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	*/
1acff8ec BJ	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	}
eee3ab16 BJ	167	break;
eee3ab16 BJ	168
290e0b0a BJ	169	/*
	170	* Mark the connection as being incapable of further output.
	171	*/
eee3ab16	172	case PRU_SHUTDOWN:
0974b45c	173	socantsendmore(so);
4aed14e3 BJ	174	tcp_usrclosed(tp);
4aed14e3 BJ	175	(void) tcp_output(tp);
72f24d7d BJ	176	break;
72f24d7d BJ	177
290e0b0a BJ	178	/*
	179	* After a receive, possibly send window update to peer.
	180	*/
eee3ab16	181	case PRU_RCVD:
f1b2fa5b	182	(void) tcp_output(tp);
72f24d7d BJ	183	break;
72f24d7d BJ	184
290e0b0a BJ	185	/*
	186	* Do a send by putting data in output queue and updating urgent
	187	* marker if URG set. Possibly send more data.
	188	*/
eee3ab16	189	case PRU_SEND:
a6503abf	190	sbappend(&so->so_snd, m);
0974b45c BJ	191	/*
0974b45c BJ	192	if (tp->t_flags & TF_PUSH)
a6503abf	193	tp->snd_end = tp->snd_una + so->so_snd.sb_cc;
0974b45c	194	*/
f1b2fa5b	195	(void) tcp_output(tp);
72f24d7d BJ	196	break;
72f24d7d BJ	197
290e0b0a BJ	198	/*
	199	* Abort the TCP.
	200	*/
eee3ab16	201	case PRU_ABORT:
a6503abf	202	tcp_drop(tp, ECONNABORTED);
72f24d7d BJ	203	break;
72f24d7d BJ	204
290e0b0a	205	/* SOME AS YET UNIMPLEMENTED HOOKS */
eee3ab16	206	case PRU_CONTROL:
53a5409e	207	error = EOPNOTSUPP;
eee3ab16 BJ	208	break;
eee3ab16 BJ	209
f1b2fa5b BJ	210	case PRU_SENSE:
	211	error = EOPNOTSUPP;
	212	break;
0244dbc7	213	/* END UNIMPLEMENTED HOOKS */
f1b2fa5b BJ	214
f1b2fa5b BJ	215	case PRU_RCVOOB:
8b5a83bb BJ	216	if (so->so_oobmark == 0 &&
8b5a83bb BJ	217	(so->so_state & SS_RCVATMARK) == 0) {
0244dbc7 BJ	218	error = EINVAL;
	219	break;
	220	}
b2db9217	221	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
8b5a83bb	222	error = EWOULDBLOCK;
b2db9217	223	break;
8b5a83bb	224	}
b2db9217	225	*mtod(m, caddr_t) = tp->t_iobc;
f1b2fa5b BJ	226	break;
	227
	228	case PRU_SENDOOB:
b2db9217 BJ	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
8b5a83bb BJ	239	if (sbspace(&so->so_snd) < -512) {
	240	error = ENOBUFS;
	241	break;
	242	}
0244dbc7 BJ	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	*/
b2db9217 BJ	249	tp->t_force = 1;
	250	(void) tcp_output(tp);
	251	tp->t_force = 0;
f1b2fa5b BJ	252	break;
f1b2fa5b BJ	253
290e0b0a BJ	254	/*
	255	* TCP slow timer went off; going through this
	256	* routine for tracing's sake.
	257	*/
eee3ab16	258	case PRU_SLOWTIMO:
a6503abf	259	tcp_timers(tp, (int)addr);
17b82ed4	260	req \|= (int)addr << 8; /* for debug's sake */
eee3ab16 BJ	261	break;
eee3ab16 BJ	262
9c5022e3 BJ	263	default:
9c5022e3 BJ	264	panic("tcp_usrreq");
72f24d7d	265	}
17b82ed4 BJ	266	if (tp && (so->so_options & SO_DEBUG))
17b82ed4 BJ	267	tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req);
72f24d7d	268	splx(s);
53a5409e	269	return (error);
4eb5d593	270	}
4aed14e3	271
306f91c9 BJ	272	int tcp_sendspace = 1024*2;
306f91c9 BJ	273	int tcp_recvspace = 1024*3;
290e0b0a BJ	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
306f91c9 BJ	287	error = in_pcbattach(so, &tcb,
306f91c9 BJ	288	tcp_sendspace, tcp_recvspace, (struct sockaddr_in *)sa);
290e0b0a BJ	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);
8e65fd66	319	else if (so->so_linger == 0)
290e0b0a BJ	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.
085a0b90	337	* We can let the user exit from the close as soon as the FIN is acked.
290e0b0a	338	*/
4aed14e3 BJ	339	tcp_usrclosed(tp)
	340	struct tcpcb *tp;
	341	{
	342
4aed14e3 BJ	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	}
085a0b90 BJ	360	if (tp->t_state >= TCPS_FIN_WAIT_2)
085a0b90 BJ	361	soisdisconnected(tp->t_inpcb->inp_socket);
4aed14e3	362	}