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

/*	tcp_usrreq.c	1.73	83/01/17	*/

#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/if.h"
#include "../net/route.h"
#include "../netinet/in.h"
#include "../netinet/in_pcb.h"
#include "../netinet/in_systm.h"
#include "../netinet/ip.h"
#include "../netinet/ip_var.h"
#include "../netinet/tcp.h"
#include "../netinet/tcp_fsm.h"
#include "../netinet/tcp_seq.h"
#include "../netinet/tcp_timer.h"
#include "../netinet/tcp_var.h"
#include "../netinet/tcpip.h"
#include "../netinet/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.
 */
/*ARGSUSED*/
tcp_usrreq(so, req, m, nam)
	struct socket *so;
	int req;
	struct mbuf *m, *nam;
{
	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);
		if (error)
			break;
		if ((so->so_options & SO_LINGER) && so->so_linger == 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)
			tp = tcp_disconnect(tp);
		else
			tp = tcp_close(tp);
		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:
		tp = 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);
		tp = tcp_usrclosed(tp);
		if (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:
		tp = 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:
		tp = 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 = soreserve(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).
 */
struct tcpcb *
tcp_disconnect(tp)
	register struct tcpcb *tp;
{
	struct socket *so = tp->t_inpcb->inp_socket;

	if (tp->t_state < TCPS_ESTABLISHED)
		tp = tcp_close(tp);
	else if (so->so_linger == 0)
		tp = tcp_drop(tp, 0);
	else {
		soisdisconnecting(so);
		sbflush(&so->so_rcv);
		tp = tcp_usrclosed(tp);
		if (tp)
			(void) tcp_output(tp);
	}
	return (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.
 */
struct tcpcb *
tcp_usrclosed(tp)
	register struct tcpcb *tp;
{

	switch (tp->t_state) {

	case TCPS_LISTEN:
	case TCPS_SYN_SENT:
		tp->t_state = TCPS_CLOSED;
		tp = 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 && tp->t_state >= TCPS_FIN_WAIT_2)
		soisdisconnected(tp->t_inpcb->inp_socket);
	return (tp);
}
Commit	Line	Data
0e3936fa	1	/* tcp_usrreq.c 1.73 83/01/17 */
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"
6e7edb25 BJ	9
6e7edb25 BJ	10	#include "../net/if.h"
c124e997	11	#include "../net/route.h"
6e7edb25	12	#include "../netinet/in.h"
839fe741 BJ	13	#include "../netinet/in_pcb.h"
839fe741 BJ	14	#include "../netinet/in_systm.h"
839fe741 BJ	15	#include "../netinet/ip.h"
	16	#include "../netinet/ip_var.h"
	17	#include "../netinet/tcp.h"
	18	#include "../netinet/tcp_fsm.h"
	19	#include "../netinet/tcp_seq.h"
	20	#include "../netinet/tcp_timer.h"
	21	#include "../netinet/tcp_var.h"
	22	#include "../netinet/tcpip.h"
	23	#include "../netinet/tcp_debug.h"
8a2f82db	24	#include <errno.h>
eee3ab16	25
290e0b0a BJ	26	/*
	27	* TCP protocol interface to socket abstraction.
	28	*/
	29	extern char *tcpstates[];
4ad99bae	30	struct tcpcb *tcp_newtcpcb();
290e0b0a	31
9c5022e3	32	/*
290e0b0a	33	* Process a TCP user request for TCP tb. If this is a send request
9c5022e3 BJ	34	* then m is the mbuf chain of send data. If this is a timer expiration
	35	* (called from the software clock routine), then timertype tells which timer.
	36	*/
a8d3bf7f	37	/ARGSUSED/
bc031e39	38	tcp_usrreq(so, req, m, nam)
eee3ab16 BJ	39	struct socket *so;
eee3ab16 BJ	40	int req;
8075bb0e	41	struct mbuf m, nam;
4eb5d593	42	{
53a5409e	43	register struct inpcb *inp = sotoinpcb(so);
cdad2eb1	44	register struct tcpcb *tp;
72f24d7d	45	int s = splnet();
eee3ab16	46	int error = 0;
17b82ed4	47	int ostate;
72f24d7d	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).
53a5409e	53	*/
0974b45c	54	if (inp == 0 && req != PRU_ATTACH) {
a6503abf	55	splx(s);
290e0b0a	56	return (EINVAL); /* XXX */
a6503abf BJ	57	}
a6503abf BJ	58	if (inp) {
cdad2eb1	59	tp = intotcpcb(inp);
8075bb0e	60	/* WHAT IF TP IS 0? */
9c5022e3	61	#ifdef KPROF
a6503abf	62	tcp_acounts[tp->t_state][req]++;
9c5022e3	63	#endif
17b82ed4	64	ostate = tp->t_state;
ebf42a75 BJ	65	} else
ebf42a75 BJ	66	ostate = 0;
eee3ab16	67	switch (req) {
4eb5d593	68
290e0b0a BJ	69	/*
290e0b0a BJ	70	* TCP attaches to socket via PRU_ATTACH, reserving space,
8075bb0e	71	* and an internet control block.
290e0b0a	72	*/
eee3ab16	73	case PRU_ATTACH:
4ad99bae	74	if (inp) {
eee3ab16	75	error = EISCONN;
cdad2eb1	76	break;
53a5409e	77	}
a1edc12b	78	error = tcp_attach(so);
a6503abf	79	if (error)
4ad99bae	80	break;
0e3936fa	81	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
8e65fd66	82	so->so_linger = TCP_LINGERTIME;
290e0b0a	83	tp = sototcpcb(so);
72f24d7d	84	break;
4eb5d593	85
290e0b0a BJ	86	/*
	87	* PRU_DETACH detaches the TCP protocol from the socket.
	88	* If the protocol state is non-embryonic, then can't
	89	* do this directly: have to initiate a PRU_DISCONNECT,
	90	* which may finish later; embryonic TCB's can just
	91	* be discarded here.
	92	*/
eee3ab16	93	case PRU_DETACH:
290e0b0a	94	if (tp->t_state > TCPS_LISTEN)
0e3936fa SL	95	tp = tcp_disconnect(tp);
	96	else
	97	tp = tcp_close(tp);
eee3ab16 BJ	98	break;
eee3ab16 BJ	99
8075bb0e BJ	100	/*
	101	* Give the socket an address.
	102	*/
	103	case PRU_BIND:
	104	error = in_pcbbind(inp, nam);
	105	if (error)
	106	break;
	107	break;
	108
	109	/*
	110	* Prepare to accept connections.
	111	*/
	112	case PRU_LISTEN:
	113	if (inp->inp_lport == 0)
	114	error = in_pcbbind(inp, (struct mbuf *)0);
	115	if (error == 0)
	116	tp->t_state = TCPS_LISTEN;
	117	break;
	118
290e0b0a BJ	119	/*
	120	* Initiate connection to peer.
	121	* Create a template for use in transmissions on this connection.
	122	* Enter SYN_SENT state, and mark socket as connecting.
	123	* Start keep-alive timer, and seed output sequence space.
	124	* Send initial segment on connection.
	125	*/
eee3ab16	126	case PRU_CONNECT:
8075bb0e BJ	127	if (inp->inp_lport == 0) {
	128	error = in_pcbbind(inp, (struct mbuf *)0);
	129	if (error)
	130	break;
	131	}
	132	error = in_pcbconnect(inp, nam);
4ad99bae	133	if (error)
53a5409e	134	break;
b454c3ea	135	tp->t_template = tcp_template(tp);
290e0b0a BJ	136	if (tp->t_template == 0) {
	137	in_pcbdisconnect(inp);
	138	error = ENOBUFS;
	139	break;
	140	}
53a5409e	141	soisconnecting(so);
a6503abf	142	tp->t_state = TCPS_SYN_SENT;
4aed14e3 BJ	143	tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
	144	tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
	145	tcp_sendseqinit(tp);
8a2f82db	146	error = tcp_output(tp);
72f24d7d	147	break;
4eb5d593	148
290e0b0a BJ	149	/*
	150	* Initiate disconnect from peer.
	151	* If connection never passed embryonic stage, just drop;
	152	* else if don't need to let data drain, then can just drop anyways,
	153	* else have to begin TCP shutdown process: mark socket disconnecting,
	154	* drain unread data, state switch to reflect user close, and
	155	* send segment (e.g. FIN) to peer. Socket will be really disconnected
	156	* when peer sends FIN and acks ours.
	157	*
	158	* SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
	159	*/
	160	case PRU_DISCONNECT:
0e3936fa	161	tp = tcp_disconnect(tp);
4aed14e3 BJ	162	break;
4aed14e3 BJ	163
290e0b0a BJ	164	/*
	165	* Accept a connection. Essentially all the work is
	166	* done at higher levels; just return the address
	167	* of the peer, storing through addr.
	168	*/
1acff8ec	169	case PRU_ACCEPT: {
8075bb0e	170	struct sockaddr_in sin = mtod(nam, struct sockaddr_in );
1acff8ec	171
8075bb0e BJ	172	nam->m_len = sizeof (struct sockaddr_in);
	173	sin->sin_family = AF_INET;
	174	sin->sin_port = inp->inp_fport;
	175	sin->sin_addr = inp->inp_faddr;
eee3ab16	176	break;
8075bb0e	177	}
eee3ab16	178
290e0b0a BJ	179	/*
	180	* Mark the connection as being incapable of further output.
	181	*/
eee3ab16	182	case PRU_SHUTDOWN:
0974b45c	183	socantsendmore(so);
0e3936fa SL	184	tp = tcp_usrclosed(tp);
	185	if (tp)
	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:
0e3936fa	213	tp = 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:
0e3936fa	261	tp = tcp_timers(tp, (int)nam);
8075bb0e	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
59965020	288	error = soreserve(so, tcp_sendspace, tcp_recvspace);
ebf42a75 BJ	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	*/
0e3936fa	316	struct tcpcb *
290e0b0a	317	tcp_disconnect(tp)
0e3936fa	318	register struct tcpcb *tp;
290e0b0a BJ	319	{
	320	struct socket *so = tp->t_inpcb->inp_socket;
	321
	322	if (tp->t_state < TCPS_ESTABLISHED)
0e3936fa	323	tp = tcp_close(tp);
8e65fd66	324	else if (so->so_linger == 0)
0e3936fa	325	tp = tcp_drop(tp, 0);
290e0b0a BJ	326	else {
	327	soisdisconnecting(so);
	328	sbflush(&so->so_rcv);
0e3936fa SL	329	tp = tcp_usrclosed(tp);
	330	if (tp)
	331	(void) tcp_output(tp);
290e0b0a	332	}
0e3936fa	333	return (tp);
290e0b0a BJ	334	}
	335
	336	/*
	337	* User issued close, and wish to trail through shutdown states:
	338	* if never received SYN, just forget it. If got a SYN from peer,
	339	* but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
	340	* If already got a FIN from peer, then almost done; go to LAST_ACK
	341	* state. In all other cases, have already sent FIN to peer (e.g.
	342	* after PRU_SHUTDOWN), and just have to play tedious game waiting
	343	* for peer to send FIN or not respond to keep-alives, etc.
085a0b90	344	* We can let the user exit from the close as soon as the FIN is acked.
290e0b0a	345	*/
0e3936fa	346	struct tcpcb *
4aed14e3	347	tcp_usrclosed(tp)
0e3936fa	348	register struct tcpcb *tp;
4aed14e3 BJ	349	{
4aed14e3 BJ	350
4aed14e3 BJ	351	switch (tp->t_state) {
	352
	353	case TCPS_LISTEN:
	354	case TCPS_SYN_SENT:
	355	tp->t_state = TCPS_CLOSED;
0e3936fa	356	tp = tcp_close(tp);
4aed14e3 BJ	357	break;
	358
	359	case TCPS_SYN_RECEIVED:
	360	case TCPS_ESTABLISHED:
	361	tp->t_state = TCPS_FIN_WAIT_1;
	362	break;
	363
	364	case TCPS_CLOSE_WAIT:
	365	tp->t_state = TCPS_LAST_ACK;
	366	break;
	367	}
0e3936fa	368	if (tp && tp->t_state >= TCPS_FIN_WAIT_2)
085a0b90	369	soisdisconnected(tp->t_inpcb->inp_socket);
0e3936fa	370	return (tp);
4aed14e3	371	}