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source: rtems/cpukit/libnetworking/netinet/tcp_usrreq.c @ 6e401331

4.104.115

Last change on this file since 6e401331 was b25b88e7, checked in by Ralf Corsepius <ralf.corsepius@…>, on 03/28/10 at 05:50:29
Add HAVE_CONFIG_H support to let files receive configure defines.
Property mode set to `100644`
File size: 19.7 KB

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1	/*
2	* Copyright (c) 1982, 1986, 1988, 1993
3	* The Regents of the University of California. All rights reserved.
4	*
5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions
7	* are met:
8	* 1. Redistributions of source code must retain the above copyright
9	* notice, this list of conditions and the following disclaimer.
10	* 2. Redistributions in binary form must reproduce the above copyright
11	* notice, this list of conditions and the following disclaimer in the
12	* documentation and/or other materials provided with the distribution.
13	* 4. Neither the name of the University nor the names of its contributors
14	* may be used to endorse or promote products derived from this software
15	* without specific prior written permission.
16	*
17	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27	* SUCH DAMAGE.
28	*
29	* From: @(#)tcp_usrreq.c 8.2 (Berkeley) 1/3/94
30	* $FreeBSD: src/sys/netinet/tcp_usrreq.c,v 1.120 2005/05/01 14:01:38 rwatson Exp $
31	*/
32
33	/*
34	* $Id$
35	*/
36
37	#ifdef HAVE_CONFIG_H
38	#include "config.h"
39	#endif
40
41	#include "opt_tcpdebug.h"
42
43	#include <sys/param.h>
44	#include <rtems/bsd/sys/queue.h>
45	#include <sys/systm.h>
46	#include <sys/kernel.h>
47	#include <sys/sysctl.h>
48	#include <sys/malloc.h>
49	#include <sys/mbuf.h>
50	#include <sys/socket.h>
51	#include <sys/socketvar.h>
52	#include <sys/protosw.h>
53	#include <errno.h>
54	#include <sys/stat.h>
55
56	#include <net/if.h>
57	#include <net/route.h>
58
59	#include <netinet/in.h>
60	#include <netinet/in_systm.h>
61	#include <netinet/ip.h>
62	#include <netinet/in_pcb.h>
63	#include <netinet/in_var.h>
64	#include <netinet/ip_var.h>
65	#include <netinet/tcp.h>
66	#include <netinet/tcp_fsm.h>
67	#include <netinet/tcp_seq.h>
68	#include <netinet/tcp_timer.h>
69	#include <netinet/tcp_var.h>
70	#include <netinet/tcpip.h>
71	#ifdef TCPDEBUG
72	#include <netinet/tcp_debug.h>
73	#endif
74
75	/*
76	* TCP protocol interface to socket abstraction.
77	*/
78	extern char *tcpstates[];
79
80	static int tcp_attach(struct socket *);
81	static int tcp_connect(struct tcpcb , struct mbuf );
82	static struct tcpcb *
83	tcp_disconnect(struct tcpcb *);
84	static struct tcpcb *
85	tcp_usrclosed(struct tcpcb *);
86
87	#ifdef TCPDEBUG
88	#define TCPDEBUG0 int ostate
89	#define TCPDEBUG1() ostate = tp ? tp->t_state : 0
90	#define TCPDEBUG2(req) if (tp && (so->so_options & SO_DEBUG)) \
91	tcp_trace(TA_USER, ostate, tp, 0, req)
92	#else
93	#define TCPDEBUG0
94	#define TCPDEBUG1()
95	#define TCPDEBUG2(req)
96	#endif
97
98	/*
99	* TCP attaches to socket via pru_attach(), reserving space,
100	* and an internet control block.
101	*/
102	static int
103	tcp_usr_attach(struct socket *so, intptr_t proto)
104	{
105	int s = splnet();
106	int error;
107	struct inpcb *inp = sotoinpcb(so);
108	struct tcpcb *tp = 0;
109	TCPDEBUG0;
110
111	TCPDEBUG1();
112	if (inp) {
113	error = EISCONN;
114	goto out;
115	}
116
117	error = tcp_attach(so);
118	if (error)
119	goto out;
120
121	if ((so->so_options & SO_LINGER) && so->so_linger == 0)
122	so->so_linger = TCP_LINGERTIME * hz;
123	tp = sototcpcb(so);
124	out:
125	TCPDEBUG2(PRU_ATTACH);
126	splx(s);
127	return error;
128	}
129
130	/*
131	* pru_detach() detaches the TCP protocol from the socket.
132	* If the protocol state is non-embryonic, then can't
133	* do this directly: have to initiate a pru_disconnect(),
134	* which may finish later; embryonic TCB's can just
135	* be discarded here.
136	*/
137	static int
138	tcp_usr_detach(struct socket *so)
139	{
140	int s = splnet();
141	int error = 0;
142	struct inpcb *inp = sotoinpcb(so);
143	struct tcpcb *tp;
144	TCPDEBUG0;
145
146	if (inp == 0) {
147	splx(s);
148	return EINVAL; /* XXX */
149	}
150	tp = intotcpcb(inp);
151	TCPDEBUG1();
152	if (tp->t_state > TCPS_LISTEN)
153	tp = tcp_disconnect(tp);
154	else
155	tp = tcp_close(tp);
156
157	TCPDEBUG2(PRU_DETACH);
158	splx(s);
159	return error;
160	}
161
162	#define COMMON_START() TCPDEBUG0; \
163	do { \
164	if (inp == 0) { \
165	splx(s); \
166	return EINVAL; \
167	} \
168	tp = intotcpcb(inp); \
169	TCPDEBUG1(); \
170	} while(0)
171
172	#define COMMON_END(req) out: TCPDEBUG2(req); splx(s); return error; goto out
173
174
175	/*
176	* Give the socket an address.
177	*/
178	static int
179	tcp_usr_bind(struct socket so, struct mbuf nam)
180	{
181	int s = splnet();
182	int error = 0;
183	struct inpcb *inp = sotoinpcb(so);
184	struct tcpcb *tp;
185	struct sockaddr_in *sinp;
186
187	COMMON_START();
188
189	/*
190	* Must check for multicast addresses and disallow binding
191	* to them.
192	*/
193	sinp = mtod(nam, struct sockaddr_in *);
194	if (sinp->sin_family == AF_INET &&
195	IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
196	error = EAFNOSUPPORT;
197	goto out;
198	}
199	error = in_pcbbind(inp, nam);
200	if (error)
201	goto out;
202	COMMON_END(PRU_BIND);
203
204	}
205
206	/*
207	* Prepare to accept connections.
208	*/
209	static int
210	tcp_usr_listen(struct socket *so)
211	{
212	int s = splnet();
213	int error = 0;
214	struct inpcb *inp = sotoinpcb(so);
215	struct tcpcb *tp;
216
217	COMMON_START();
218	if (inp->inp_lport == 0)
219	error = in_pcbbind(inp, NULL);
220	if (error == 0)
221	tp->t_state = TCPS_LISTEN;
222	COMMON_END(PRU_LISTEN);
223	}
224
225	/*
226	* Initiate connection to peer.
227	* Create a template for use in transmissions on this connection.
228	* Enter SYN_SENT state, and mark socket as connecting.
229	* Start keep-alive timer, and seed output sequence space.
230	* Send initial segment on connection.
231	*/
232	static int
233	tcp_usr_connect(struct socket so, struct mbuf nam)
234	{
235	int s = splnet();
236	int error = 0;
237	struct inpcb *inp = sotoinpcb(so);
238	struct tcpcb *tp;
239	struct sockaddr_in *sinp;
240
241	COMMON_START();
242
243	/*
244	* Must disallow TCP ``connections'' to multicast addresses.
245	*/
246	sinp = mtod(nam, struct sockaddr_in *);
247	if (sinp->sin_family == AF_INET
248	&& IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
249	error = EAFNOSUPPORT;
250	goto out;
251	}
252
253	if ((error = tcp_connect(tp, nam)) != 0)
254	goto out;
255	error = tcp_output(tp);
256	COMMON_END(PRU_CONNECT);
257	}
258
259	/*
260	* Initiate disconnect from peer.
261	* If connection never passed embryonic stage, just drop;
262	* else if don't need to let data drain, then can just drop anyways,
263	* else have to begin TCP shutdown process: mark socket disconnecting,
264	* drain unread data, state switch to reflect user close, and
265	* send segment (e.g. FIN) to peer. Socket will be really disconnected
266	* when peer sends FIN and acks ours.
267	*
268	* SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
269	*/
270	static int
271	tcp_usr_disconnect(struct socket *so)
272	{
273	int s = splnet();
274	int error = 0;
275	struct inpcb *inp = sotoinpcb(so);
276	struct tcpcb *tp;
277
278	COMMON_START();
279	tp = tcp_disconnect(tp);
280	COMMON_END(PRU_DISCONNECT);
281	}
282
283	/*
284	* Accept a connection. Essentially all the work is
285	* done at higher levels; just return the address
286	* of the peer, storing through addr.
287	*/
288	static int
289	tcp_usr_accept(struct socket so, struct mbuf nam)
290	{
291	int s = splnet();
292	int error = 0;
293	struct inpcb *inp = sotoinpcb(so);
294	struct tcpcb *tp;
295
296	COMMON_START();
297	in_setpeeraddr(inp, nam);
298	COMMON_END(PRU_ACCEPT);
299	}
300
301	/*
302	* Mark the connection as being incapable of further output.
303	*/
304	static int
305	tcp_usr_shutdown(struct socket *so)
306	{
307	int s = splnet();
308	int error = 0;
309	struct inpcb *inp = sotoinpcb(so);
310	struct tcpcb *tp;
311
312	COMMON_START();
313	socantsendmore(so);
314	tp = tcp_usrclosed(tp);
315	if (tp)
316	error = tcp_output(tp);
317	COMMON_END(PRU_SHUTDOWN);
318	}
319
320	/*
321	* After a receive, possibly send window update to peer.
322	*/
323	static int
324	tcp_usr_rcvd(struct socket *so, intptr_t flags)
325	{
326	int s = splnet();
327	int error = 0;
328	struct inpcb *inp = sotoinpcb(so);
329	struct tcpcb *tp;
330
331	COMMON_START();
332	tcp_output(tp);
333	COMMON_END(PRU_RCVD);
334	}
335
336	/*
337	* Do a send by putting data in output queue and updating urgent
338	* marker if URG set. Possibly send more data.
339	*/
340	static int
341	tcp_usr_send(struct socket so, int flags, struct mbuf m, struct mbuf *nam,
342	struct mbuf *control)
343	{
344	int s = splnet();
345	int error = 0;
346	struct inpcb *inp = sotoinpcb(so);
347	struct tcpcb *tp;
348
349	COMMON_START();
350	if (control && control->m_len) {
351	m_freem(control); /* XXX shouldn't caller do this??? */
352	if (m)
353	m_freem(m);
354	error = EINVAL;
355	goto out;
356	}
357
358	if(!(flags & PRUS_OOB)) {
359	sbappend(&so->so_snd, m);
360	if (nam && tp->t_state < TCPS_SYN_SENT) {
361	/*
362	* Do implied connect if not yet connected,
363	* initialize window to default value, and
364	* initialize maxseg/maxopd using peer's cached
365	* MSS.
366	*/
367	error = tcp_connect(tp, nam);
368	if (error)
369	goto out;
370	tp->snd_wnd = TTCP_CLIENT_SND_WND;
371	tcp_mss(tp, -1);
372	}
373
374	if (flags & PRUS_EOF) {
375	/*
376	* Close the send side of the connection after
377	* the data is sent.
378	*/
379	socantsendmore(so);
380	tp = tcp_usrclosed(tp);
381	}
382	if (tp != NULL)
383	error = tcp_output(tp);
384	} else {
385	if (sbspace(&so->so_snd) < -512) {
386	m_freem(m);
387	error = ENOBUFS;
388	goto out;
389	}
390	/*
391	* According to RFC961 (Assigned Protocols),
392	* the urgent pointer points to the last octet
393	* of urgent data. We continue, however,
394	* to consider it to indicate the first octet
395	* of data past the urgent section.
396	* Otherwise, snd_up should be one lower.
397	*/
398	sbappend(&so->so_snd, m);
399	if (nam && tp->t_state < TCPS_SYN_SENT) {
400	/*
401	* Do implied connect if not yet connected,
402	* initialize window to default value, and
403	* initialize maxseg/maxopd using peer's cached
404	* MSS.
405	*/
406	error = tcp_connect(tp, nam);
407	if (error)
408	goto out;
409	tp->snd_wnd = TTCP_CLIENT_SND_WND;
410	tcp_mss(tp, -1);
411	}
412	tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
413	tp->t_force = 1;
414	error = tcp_output(tp);
415	tp->t_force = 0;
416	}
417	COMMON_END((flags & PRUS_OOB) ? PRU_SENDOOB :
418	((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
419	}
420
421	/*
422	* Abort the TCP.
423	*/
424	static int
425	tcp_usr_abort(struct socket *so)
426	{
427	int s = splnet();
428	int error = 0;
429	struct inpcb *inp = sotoinpcb(so);
430	struct tcpcb *tp;
431
432	COMMON_START();
433	tp = tcp_drop(tp, ECONNABORTED);
434	COMMON_END(PRU_ABORT);
435	}
436
437	/*
438	* Fill in st_bklsize for fstat() operations on a socket.
439	*/
440	static int
441	tcp_usr_sense(struct socket so, struct stat sb)
442	{
443	int s = splnet();
444
445	sb->st_blksize = so->so_snd.sb_hiwat;
446	splx(s);
447	return 0;
448	}
449
450	/*
451	* Receive out-of-band data.
452	*/
453	static int
454	tcp_usr_rcvoob(struct socket so, struct mbuf m, intptr_t flags)
455	{
456	int s = splnet();
457	int error = 0;
458	struct inpcb *inp = sotoinpcb(so);
459	struct tcpcb *tp;
460
461	COMMON_START();
462	if ((so->so_oobmark == 0 &&
463	(so->so_state & SS_RCVATMARK) == 0) \|\|
464	so->so_options & SO_OOBINLINE \|\|
465	tp->t_oobflags & TCPOOB_HADDATA) {
466	error = EINVAL;
467	goto out;
468	}
469	if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
470	error = EWOULDBLOCK;
471	goto out;
472	}
473	m->m_len = 1;
474	*mtod(m, caddr_t) = tp->t_iobc;
475	if ((flags & MSG_PEEK) == 0)
476	tp->t_oobflags ^= (TCPOOB_HAVEDATA \| TCPOOB_HADDATA);
477	COMMON_END(PRU_RCVOOB);
478	}
479
480	static int
481	tcp_usr_sockaddr(struct socket so, struct mbuf nam)
482	{
483	int s = splnet();
484	int error = 0;
485	struct inpcb *inp = sotoinpcb(so);
486	struct tcpcb *tp;
487
488	COMMON_START();
489	in_setsockaddr(inp, nam);
490	COMMON_END(PRU_SOCKADDR);
491	}
492
493	static int
494	tcp_usr_peeraddr(struct socket so, struct mbuf nam)
495	{
496	int s = splnet();
497	int error = 0;
498	struct inpcb *inp = sotoinpcb(so);
499	struct tcpcb *tp;
500
501	COMMON_START();
502	in_setpeeraddr(inp, nam);
503	COMMON_END(PRU_PEERADDR);
504	}
505
506	/*
507	* XXX - this should just be a call to in_control, but we need to get
508	* the types worked out.
509	*/
510	static int
511	tcp_usr_control(struct socket so, intptr_t cmd, caddr_t arg, struct ifnet ifp)
512	{
513	return in_control(so, cmd, arg, ifp);
514	}
515
516	/* xxx - should be const */
517	struct pr_usrreqs tcp_usrreqs = {
518	tcp_usr_abort, tcp_usr_accept, tcp_usr_attach, tcp_usr_bind,
519	tcp_usr_connect, pru_connect2_notsupp, tcp_usr_control, tcp_usr_detach,
520	tcp_usr_disconnect, tcp_usr_listen, tcp_usr_peeraddr, tcp_usr_rcvd,
521	tcp_usr_rcvoob, tcp_usr_send, tcp_usr_sense, tcp_usr_shutdown,
522	tcp_usr_sockaddr
523	};
524
525	/*
526	* Common subroutine to open a TCP connection to remote host specified
527	* by struct sockaddr_in in mbuf *nam. Call in_pcbbind to assign a local
528	* port number if needed. Call in_pcbladdr to do the routing and to choose
529	* a local host address (interface). If there is an existing incarnation
530	* of the same connection in TIME-WAIT state and if the remote host was
531	* sending CC options and if the connection duration was < MSL, then
532	* truncate the previous TIME-WAIT state and proceed.
533	* Initialize connection parameters and enter SYN-SENT state.
534	*/
535	static int
536	tcp_connect(struct tcpcb tp, struct mbuf nam)
537	{
538	struct inpcb inp = tp->t_inpcb, oinp;
539	struct socket *so = inp->inp_socket;
540	struct tcpcb *otp;
541	struct sockaddr_in sin = mtod(nam, struct sockaddr_in );
542	struct sockaddr_in *ifaddr;
543	int error;
544	struct rmxp_tao *taop;
545	struct rmxp_tao tao_noncached;
546
547	if (inp->inp_lport == 0) {
548	error = in_pcbbind(inp, NULL);
549	if (error)
550	return error;
551	}
552
553	/*
554	* Cannot simply call in_pcbconnect, because there might be an
555	* earlier incarnation of this same connection still in
556	* TIME_WAIT state, creating an ADDRINUSE error.
557	*/
558	error = in_pcbladdr(inp, nam, &ifaddr);
559	if (error)
560	return error;
561	oinp = in_pcblookuphash(inp->inp_pcbinfo,
562	sin->sin_addr, sin->sin_port,
563	inp->inp_laddr.s_addr != INADDR_ANY ? inp->inp_laddr
564	: ifaddr->sin_addr,
565	inp->inp_lport, 0);
566	if (oinp) {
567	if (oinp != inp && (otp = intotcpcb(oinp)) != NULL &&
568	otp->t_state == TCPS_TIME_WAIT &&
569	otp->t_duration < TCPTV_MSL &&
570	(otp->t_flags & TF_RCVD_CC))
571	otp = tcp_close(otp);
572	else
573	return EADDRINUSE;
574	}
575	if (inp->inp_laddr.s_addr == INADDR_ANY)
576	inp->inp_laddr = ifaddr->sin_addr;
577	inp->inp_faddr = sin->sin_addr;
578	inp->inp_fport = sin->sin_port;
579	in_pcbrehash(inp);
580
581	tp->t_template = tcp_template(tp);
582	if (tp->t_template == 0) {
583	in_pcbdisconnect(inp);
584	return ENOBUFS;
585	}
586
587	/* Compute window scaling to request. */
588	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
589	(TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
590	tp->request_r_scale++;
591
592	soisconnecting(so);
593	tcpstat.tcps_connattempt++;
594	tp->t_state = TCPS_SYN_SENT;
595	tp->t_timer[TCPT_KEEP] = tcp_keepinit;
596	tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
597	tcp_sendseqinit(tp);
598
599	/*
600	* Generate a CC value for this connection and
601	* check whether CC or CCnew should be used.
602	*/
603	if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) {
604	taop = &tao_noncached;
605	bzero(taop, sizeof(*taop));
606	}
607
608	tp->cc_send = CC_INC(tcp_ccgen);
609	if (taop->tao_ccsent != 0 &&
610	CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
611	taop->tao_ccsent = tp->cc_send;
612	} else {
613	taop->tao_ccsent = 0;
614	tp->t_flags \|= TF_SENDCCNEW;
615	}
616
617	return 0;
618	}
619
620	int
621	tcp_ctloutput(int op, struct socket *so, int level, int optname,
622	struct mbuf **mp)
623	{
624	int error = 0, s;
625	struct inpcb *inp;
626	register struct tcpcb *tp;
627	register struct mbuf *m;
628	register int i;
629
630	s = splnet();
631	inp = sotoinpcb(so);
632	if (inp == NULL) {
633	splx(s);
634	if (op == PRCO_SETOPT && *mp)
635	(void) m_free(*mp);
636	return (ECONNRESET);
637	}
638	if (level != IPPROTO_TCP) {
639	error = ip_ctloutput(op, so, level, optname, mp);
640	splx(s);
641	return (error);
642	}
643	tp = intotcpcb(inp);
644
645	switch (op) {
646
647	case PRCO_SETOPT:
648	m = *mp;
649	switch (optname) {
650
651	case TCP_NODELAY:
652	if (m == NULL \|\| m->m_len < sizeof (int))
653	error = EINVAL;
654	else if (mtod(m, int ))
655	tp->t_flags \|= TF_NODELAY;
656	else
657	tp->t_flags &= ~TF_NODELAY;
658	break;
659
660	case TCP_MAXSEG:
661	if (m && (i = mtod(m, int )) > 0 && i <= tp->t_maxseg)
662	tp->t_maxseg = i;
663	else
664	error = EINVAL;
665	break;
666
667	case TCP_NOOPT:
668	if (m == NULL \|\| m->m_len < sizeof (int))
669	error = EINVAL;
670	else if (mtod(m, int ))
671	tp->t_flags \|= TF_NOOPT;
672	else
673	tp->t_flags &= ~TF_NOOPT;
674	break;
675
676	case TCP_NOPUSH:
677	if (m == NULL \|\| m->m_len < sizeof (int))
678	error = EINVAL;
679	else if (mtod(m, int ))
680	tp->t_flags \|= TF_NOPUSH;
681	else
682	tp->t_flags &= ~TF_NOPUSH;
683	break;
684
685	default:
686	error = ENOPROTOOPT;
687	break;
688	}
689	if (m)
690	(void) m_free(m);
691	break;
692
693	case PRCO_GETOPT:
694	*mp = m = m_get(M_WAIT, MT_SOOPTS);
695	m->m_len = sizeof(int);
696
697	switch (optname) {
698	case TCP_NODELAY:
699	mtod(m, int ) = tp->t_flags & TF_NODELAY;
700	break;
701	case TCP_MAXSEG:
702	mtod(m, int ) = tp->t_maxseg;
703	break;
704	case TCP_NOOPT:
705	mtod(m, int ) = tp->t_flags & TF_NOOPT;
706	break;
707	case TCP_NOPUSH:
708	mtod(m, int ) = tp->t_flags & TF_NOPUSH;
709	break;
710	default:
711	error = ENOPROTOOPT;
712	break;
713	}
714	break;
715	}
716	splx(s);
717	return (error);
718	}
719
720	/*
721	* tcp_sendspace and tcp_recvspace are the default send and receive window
722	* sizes, respectively. These are obsolescent (this information should
723	* be set by the route).
724	*/
725	u_long tcp_sendspace = 1024*16;
726	SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace,
727	CTLFLAG_RW, &tcp_sendspace , 0, "");
728	u_long tcp_recvspace = 1024*16;
729	SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace,
730	CTLFLAG_RW, &tcp_recvspace , 0, "");
731
732	#if defined(__rtems__)
733	void rtems_set_tcp_buffer_sizes(u_long sendspace, u_long recvspace)
734	{
735	if ( sendspace != 0 )
736	tcp_sendspace = sendspace;
737	if ( recvspace != 0 )
738	tcp_recvspace = recvspace;
739	}
740	#endif
741
742	/*
743	* Attach TCP protocol to socket, allocating
744	* internet protocol control block, tcp control block,
745	* bufer space, and entering LISTEN state if to accept connections.
746	*/
747	static int
748	tcp_attach(struct socket *so)
749	{
750	register struct tcpcb *tp;
751	struct inpcb *inp;
752	int error;
753
754	if (so->so_snd.sb_hiwat == 0 \|\| so->so_rcv.sb_hiwat == 0) {
755	error = soreserve(so, tcp_sendspace, tcp_recvspace);
756	if (error)
757	return (error);
758	}
759	error = in_pcballoc(so, &tcbinfo);
760	if (error)
761	return (error);
762	inp = sotoinpcb(so);
763	tp = tcp_newtcpcb(inp);
764	if (tp == 0) {
765	int nofd = so->so_state & SS_NOFDREF; /* XXX */
766
767	so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */
768	in_pcbdetach(inp);
769	so->so_state \|= nofd;
770	return (ENOBUFS);
771	}
772	tp->t_state = TCPS_CLOSED;
773	return (0);
774	}
775
776	/*
777	* Initiate (or continue) disconnect.
778	* If embryonic state, just send reset (once).
779	* If in ``let data drain'' option and linger null, just drop.
780	* Otherwise (hard), mark socket disconnecting and drop
781	* current input data; switch states based on user close, and
782	* send segment to peer (with FIN).
783	*/
784	static struct tcpcb *
785	tcp_disconnect(struct tcpcb *tp)
786	{
787	struct socket *so = tp->t_inpcb->inp_socket;
788
789	if (tp->t_state < TCPS_ESTABLISHED)
790	tp = tcp_close(tp);
791	else if ((so->so_options & SO_LINGER) && so->so_linger == 0)
792	tp = tcp_drop(tp, 0);
793	else {
794	soisdisconnecting(so);
795	sbflush(&so->so_rcv);
796	tp = tcp_usrclosed(tp);
797	if (tp)
798	(void) tcp_output(tp);
799	}
800	return (tp);
801	}
802
803	/*
804	* User issued close, and wish to trail through shutdown states:
805	* if never received SYN, just forget it. If got a SYN from peer,
806	* but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
807	* If already got a FIN from peer, then almost done; go to LAST_ACK
808	* state. In all other cases, have already sent FIN to peer (e.g.
809	* after PRU_SHUTDOWN), and just have to play tedious game waiting
810	* for peer to send FIN or not respond to keep-alives, etc.
811	* We can let the user exit from the close as soon as the FIN is acked.
812	*/
813	static struct tcpcb *
814	tcp_usrclosed(struct tcpcb *tp)
815	{
816
817	switch (tp->t_state) {
818
819	case TCPS_CLOSED:
820	case TCPS_LISTEN:
821	tp->t_state = TCPS_CLOSED;
822	tp = tcp_close(tp);
823	break;
824
825	case TCPS_SYN_SENT:
826	case TCPS_SYN_RECEIVED:
827	tp->t_flags \|= TF_NEEDFIN;
828	break;
829
830	case TCPS_ESTABLISHED:
831	tp->t_state = TCPS_FIN_WAIT_1;
832	break;
833
834	case TCPS_CLOSE_WAIT:
835	tp->t_state = TCPS_LAST_ACK;
836	break;
837	}
838	if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
839	soisdisconnected(tp->t_inpcb->inp_socket);
840	/* To prevent the connection hanging in FIN_WAIT_2 forever. */
841	if (tp->t_state == TCPS_FIN_WAIT_2)
842	tp->t_timer[TCPT_2MSL] = tcp_maxidle;
843	}
844	return (tp);
845	}

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