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

/*	tcp_usrreq.c	1.64	82/10/05	*/

#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, nam, opt)
	struct socket *so;
	int req;
	struct mbuf *m, *nam;
	struct socketopt *opt;
{
	register struct inpcb *inp = sotoinpcb(so);
	register struct tcpcb *tp;
	int s = splnet();
	int error = 0;
	int ostate;

	/*
	 * 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).
	 */
	if (inp == 0 && req != PRU_ATTACH) {
		splx(s);
		return (EINVAL);		/* XXX */
	}
	if (inp) {
		tp = intotcpcb(inp);
		/* WHAT IF TP IS 0? */
#ifdef KPROF
		tcp_acounts[tp->t_state][req]++;
#endif
		ostate = tp->t_state;
	} else
		ostate = 0;
	switch (req) {

	/*
	 * TCP attaches to socket via PRU_ATTACH, reserving space,
	 * and an internet control block.
	 */
	case PRU_ATTACH:
		if (inp) {
			error = EISCONN;
			break;
		}
		error = tcp_attach(so, nam);
		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;

	/*
	 * Give the socket an address.
	 */
	case PRU_BIND:
		error = in_pcbbind(inp, nam);
		if (error)
			break;
		break;

	/*
	 * Prepare to accept connections.
	 */
	case PRU_LISTEN:
		if (inp->inp_lport == 0)
			error = in_pcbbind(inp, (struct mbuf *)0);
		if (error == 0)
			tp->t_state = TCPS_LISTEN;
		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:
		if (inp->inp_lport == 0) {
			error = in_pcbbind(inp, (struct mbuf *)0);
			if (error)
				break;
		}
		error = in_pcbconnect(inp, nam);
		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);
		error = 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 = mtod(nam, struct sockaddr_in *);

		nam->m_len = sizeof (struct sockaddr_in);
		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);
		error = 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);
#ifdef notdef
		if (tp->t_flags & TF_PUSH)
			tp->snd_end = tp->snd_una + so->so_snd.sb_cc;
#endif
		error = 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;
		}
		m->m_len = 1;
		*mtod(m, caddr_t) = tp->t_iobc;
		break;

	case PRU_SENDOOB:
		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);
		tp->t_force = 1;
		error = tcp_output(tp);
		tp->t_force = 0;
		break;

	case PRU_SOCKADDR:
		in_setsockaddr(inp, nam);
		break;

	/*
	 * TCP slow timer went off; going through this
	 * routine for tracing's sake.
	 */
	case PRU_SLOWTIMO:
		tcp_timers(tp, (int)nam);
		req |= (int)nam << 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*2;
/*
 * 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)
	struct socket *so;
{
	register struct tcpcb *tp;
	struct inpcb *inp;
	int error;

	error = in_pcbreserve(so, tcp_sendspace, tcp_recvspace);
	if (error)
		goto bad;
	error = in_pcballoc(so, &tcb);
	if (error)
		goto bad;
	inp = sotoinpcb(so);
	tp = tcp_newtcpcb(inp);
	if (tp == 0) {
		error = ENOBUFS;
		goto bad2;
	}
	tp->t_state = TCPS_CLOSED;
	return (0);
bad2:
	in_pcbdetach(inp);
bad:
	return (error);
}

/*
 * 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
77a4e3ca	1	/* tcp_usrreq.c 1.64 82/10/05 */
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"
8a2f82db	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	*/
8075bb0e	36	tcp_usrreq(so, req, m, nam, opt)
eee3ab16 BJ	37	struct socket *so;
eee3ab16 BJ	38	int req;
8075bb0e BJ	39	struct mbuf m, nam;
8075bb0e BJ	40	struct socketopt *opt;
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	47
53a5409e	48	/*
290e0b0a BJ	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).
53a5409e	52	*/
0974b45c	53	if (inp == 0 && req != PRU_ATTACH) {
a6503abf	54	splx(s);
290e0b0a	55	return (EINVAL); /* XXX */
a6503abf BJ	56	}
a6503abf BJ	57	if (inp) {
cdad2eb1	58	tp = intotcpcb(inp);
8075bb0e	59	/* WHAT IF TP IS 0? */
9c5022e3	60	#ifdef KPROF
a6503abf	61	tcp_acounts[tp->t_state][req]++;
9c5022e3	62	#endif
17b82ed4	63	ostate = tp->t_state;
ebf42a75 BJ	64	} else
ebf42a75 BJ	65	ostate = 0;
eee3ab16	66	switch (req) {
4eb5d593	67
290e0b0a BJ	68	/*
290e0b0a BJ	69	* TCP attaches to socket via PRU_ATTACH, reserving space,
8075bb0e	70	* and an internet control block.
290e0b0a	71	*/
eee3ab16	72	case PRU_ATTACH:
4ad99bae	73	if (inp) {
eee3ab16	74	error = EISCONN;
cdad2eb1	75	break;
53a5409e	76	}
8075bb0e	77	error = tcp_attach(so, nam);
a6503abf	78	if (error)
4ad99bae	79	break;
8e65fd66 BJ	80	if ((so->so_options & SO_DONTLINGER) == 0)
8e65fd66 BJ	81	so->so_linger = TCP_LINGERTIME;
290e0b0a	82	tp = sototcpcb(so);
72f24d7d	83	break;
4eb5d593	84
290e0b0a BJ	85	/*
	86	* PRU_DETACH detaches the TCP protocol from the socket.
	87	* If the protocol state is non-embryonic, then can't
	88	* do this directly: have to initiate a PRU_DISCONNECT,
	89	* which may finish later; embryonic TCB's can just
	90	* be discarded here.
	91	*/
eee3ab16	92	case PRU_DETACH:
290e0b0a BJ	93	if (tp->t_state > TCPS_LISTEN)
	94	tcp_disconnect(tp);
	95	else {
	96	tcp_close(tp);
	97	tp = 0;
	98	}
eee3ab16 BJ	99	break;
eee3ab16 BJ	100
8075bb0e BJ	101	/*
	102	* Give the socket an address.
	103	*/
	104	case PRU_BIND:
	105	error = in_pcbbind(inp, nam);
	106	if (error)
	107	break;
	108	break;
	109
	110	/*
	111	* Prepare to accept connections.
	112	*/
	113	case PRU_LISTEN:
	114	if (inp->inp_lport == 0)
	115	error = in_pcbbind(inp, (struct mbuf *)0);
	116	if (error == 0)
	117	tp->t_state = TCPS_LISTEN;
	118	break;
	119
290e0b0a BJ	120	/*
	121	* Initiate connection to peer.
	122	* Create a template for use in transmissions on this connection.
	123	* Enter SYN_SENT state, and mark socket as connecting.
	124	* Start keep-alive timer, and seed output sequence space.
	125	* Send initial segment on connection.
	126	*/
eee3ab16	127	case PRU_CONNECT:
8075bb0e BJ	128	if (inp->inp_lport == 0) {
	129	error = in_pcbbind(inp, (struct mbuf *)0);
	130	if (error)
	131	break;
	132	}
	133	error = in_pcbconnect(inp, nam);
4ad99bae	134	if (error)
53a5409e	135	break;
b454c3ea	136	tp->t_template = tcp_template(tp);
290e0b0a BJ	137	if (tp->t_template == 0) {
	138	in_pcbdisconnect(inp);
	139	error = ENOBUFS;
	140	break;
	141	}
53a5409e	142	soisconnecting(so);
a6503abf	143	tp->t_state = TCPS_SYN_SENT;
4aed14e3 BJ	144	tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
	145	tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
	146	tcp_sendseqinit(tp);
8a2f82db	147	error = tcp_output(tp);
72f24d7d	148	break;
4eb5d593	149
290e0b0a BJ	150	/*
	151	* Initiate disconnect from peer.
	152	* If connection never passed embryonic stage, just drop;
	153	* else if don't need to let data drain, then can just drop anyways,
	154	* else have to begin TCP shutdown process: mark socket disconnecting,
	155	* drain unread data, state switch to reflect user close, and
	156	* send segment (e.g. FIN) to peer. Socket will be really disconnected
	157	* when peer sends FIN and acks ours.
	158	*
	159	* SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
	160	*/
	161	case PRU_DISCONNECT:
	162	tcp_disconnect(tp);
4aed14e3 BJ	163	break;
4aed14e3 BJ	164
290e0b0a BJ	165	/*
	166	* Accept a connection. Essentially all the work is
	167	* done at higher levels; just return the address
	168	* of the peer, storing through addr.
	169	*/
1acff8ec	170	case PRU_ACCEPT: {
8075bb0e	171	struct sockaddr_in sin = mtod(nam, struct sockaddr_in );
1acff8ec	172
8075bb0e BJ	173	nam->m_len = sizeof (struct sockaddr_in);
	174	sin->sin_family = AF_INET;
	175	sin->sin_port = inp->inp_fport;
	176	sin->sin_addr = inp->inp_faddr;
eee3ab16	177	break;
8075bb0e	178	}
eee3ab16	179
290e0b0a BJ	180	/*
	181	* Mark the connection as being incapable of further output.
	182	*/
eee3ab16	183	case PRU_SHUTDOWN:
0974b45c	184	socantsendmore(so);
4aed14e3	185	tcp_usrclosed(tp);
8a2f82db	186	error = tcp_output(tp);
72f24d7d BJ	187	break;
72f24d7d BJ	188
290e0b0a BJ	189	/*
	190	* After a receive, possibly send window update to peer.
	191	*/
eee3ab16	192	case PRU_RCVD:
f1b2fa5b	193	(void) tcp_output(tp);
72f24d7d BJ	194	break;
72f24d7d BJ	195
290e0b0a BJ	196	/*
	197	* Do a send by putting data in output queue and updating urgent
	198	* marker if URG set. Possibly send more data.
	199	*/
eee3ab16	200	case PRU_SEND:
a6503abf	201	sbappend(&so->so_snd, m);
8a2f82db	202	#ifdef notdef
0974b45c	203	if (tp->t_flags & TF_PUSH)
a6503abf	204	tp->snd_end = tp->snd_una + so->so_snd.sb_cc;
8a2f82db SL	205	#endif
8a2f82db SL	206	error = tcp_output(tp);
72f24d7d BJ	207	break;
72f24d7d BJ	208
290e0b0a BJ	209	/*
	210	* Abort the TCP.
	211	*/
eee3ab16	212	case PRU_ABORT:
a6503abf	213	tcp_drop(tp, ECONNABORTED);
72f24d7d BJ	214	break;
72f24d7d BJ	215
290e0b0a	216	/* SOME AS YET UNIMPLEMENTED HOOKS */
eee3ab16	217	case PRU_CONTROL:
53a5409e	218	error = EOPNOTSUPP;
eee3ab16 BJ	219	break;
eee3ab16 BJ	220
f1b2fa5b BJ	221	case PRU_SENSE:
	222	error = EOPNOTSUPP;
	223	break;
0244dbc7	224	/* END UNIMPLEMENTED HOOKS */
f1b2fa5b BJ	225
f1b2fa5b BJ	226	case PRU_RCVOOB:
8b5a83bb BJ	227	if (so->so_oobmark == 0 &&
8b5a83bb BJ	228	(so->so_state & SS_RCVATMARK) == 0) {
0244dbc7 BJ	229	error = EINVAL;
	230	break;
	231	}
b2db9217	232	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
8b5a83bb	233	error = EWOULDBLOCK;
b2db9217	234	break;
8b5a83bb	235	}
283ea225	236	m->m_len = 1;
b2db9217	237	*mtod(m, caddr_t) = tp->t_iobc;
f1b2fa5b BJ	238	break;
	239
	240	case PRU_SENDOOB:
8b5a83bb BJ	241	if (sbspace(&so->so_snd) < -512) {
	242	error = ENOBUFS;
	243	break;
	244	}
0244dbc7 BJ	245	tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1;
0244dbc7 BJ	246	sbappend(&so->so_snd, m);
b2db9217	247	tp->t_force = 1;
8a2f82db	248	error = tcp_output(tp);
b2db9217	249	tp->t_force = 0;
f1b2fa5b BJ	250	break;
f1b2fa5b BJ	251
126472ab	252	case PRU_SOCKADDR:
8075bb0e	253	in_setsockaddr(inp, nam);
126472ab SL	254	break;
126472ab SL	255
290e0b0a BJ	256	/*
	257	* TCP slow timer went off; going through this
	258	* routine for tracing's sake.
	259	*/
eee3ab16	260	case PRU_SLOWTIMO:
8075bb0e BJ	261	tcp_timers(tp, (int)nam);
8075bb0e BJ	262	req \|= (int)nam << 8; /* for debug's sake */
eee3ab16 BJ	263	break;
eee3ab16 BJ	264
9c5022e3 BJ	265	default:
9c5022e3 BJ	266	panic("tcp_usrreq");
72f24d7d	267	}
17b82ed4 BJ	268	if (tp && (so->so_options & SO_DEBUG))
17b82ed4 BJ	269	tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req);
72f24d7d	270	splx(s);
53a5409e	271	return (error);
4eb5d593	272	}
4aed14e3	273
306f91c9	274	int tcp_sendspace = 1024*2;
1bc20e72	275	int tcp_recvspace = 1024*2;
290e0b0a BJ	276	/*
	277	* Attach TCP protocol to socket, allocating
	278	* internet protocol control block, tcp control block,
	279	* bufer space, and entering LISTEN state if to accept connections.
	280	*/
8075bb0e	281	tcp_attach(so)
290e0b0a	282	struct socket *so;
290e0b0a BJ	283	{
	284	register struct tcpcb *tp;
	285	struct inpcb *inp;
	286	int error;
	287
ebf42a75 BJ	288	error = in_pcbreserve(so, tcp_sendspace, tcp_recvspace);
	289	if (error)
	290	goto bad;
	291	error = in_pcballoc(so, &tcb);
290e0b0a	292	if (error)
8075bb0e BJ	293	goto bad;
8075bb0e BJ	294	inp = sotoinpcb(so);
290e0b0a	295	tp = tcp_newtcpcb(inp);
ebf42a75 BJ	296	if (tp == 0) {
	297	error = ENOBUFS;
	298	goto bad2;
	299	}
8075bb0e	300	tp->t_state = TCPS_CLOSED;
290e0b0a	301	return (0);
ebf42a75 BJ	302	bad2:
	303	in_pcbdetach(inp);
	304	bad:
	305	return (error);
290e0b0a BJ	306	}
	307
	308	/*
	309	* Initiate (or continue) disconnect.
	310	* If embryonic state, just send reset (once).
	311	* If not in ``let data drain'' option, just drop.
	312	* Otherwise (hard), mark socket disconnecting and drop
	313	* current input data; switch states based on user close, and
	314	* send segment to peer (with FIN).
	315	*/
	316	tcp_disconnect(tp)
	317	struct tcpcb *tp;
	318	{
	319	struct socket *so = tp->t_inpcb->inp_socket;
	320
	321	if (tp->t_state < TCPS_ESTABLISHED)
	322	tcp_close(tp);
8e65fd66	323	else if (so->so_linger == 0)
290e0b0a BJ	324	tcp_drop(tp, 0);
	325	else {
	326	soisdisconnecting(so);
	327	sbflush(&so->so_rcv);
	328	tcp_usrclosed(tp);
	329	(void) tcp_output(tp);
	330	}
	331	}
	332
	333	/*
	334	* User issued close, and wish to trail through shutdown states:
	335	* if never received SYN, just forget it. If got a SYN from peer,
	336	* but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
	337	* If already got a FIN from peer, then almost done; go to LAST_ACK
	338	* state. In all other cases, have already sent FIN to peer (e.g.
	339	* after PRU_SHUTDOWN), and just have to play tedious game waiting
	340	* for peer to send FIN or not respond to keep-alives, etc.
085a0b90	341	* We can let the user exit from the close as soon as the FIN is acked.
290e0b0a	342	*/
4aed14e3 BJ	343	tcp_usrclosed(tp)
	344	struct tcpcb *tp;
	345	{
	346
4aed14e3 BJ	347	switch (tp->t_state) {
	348
	349	case TCPS_LISTEN:
	350	case TCPS_SYN_SENT:
	351	tp->t_state = TCPS_CLOSED;
	352	tcp_close(tp);
	353	break;
	354
	355	case TCPS_SYN_RECEIVED:
	356	case TCPS_ESTABLISHED:
	357	tp->t_state = TCPS_FIN_WAIT_1;
	358	break;
	359
	360	case TCPS_CLOSE_WAIT:
	361	tp->t_state = TCPS_LAST_ACK;
	362	break;
	363	}
085a0b90 BJ	364	if (tp->t_state >= TCPS_FIN_WAIT_2)
085a0b90 BJ	365	soisdisconnected(tp->t_inpcb->inp_socket);
4aed14e3	366	}