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1.1 root 1: /*
2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: /*
23: * Copyright (c) 1982, 1986, 1988, 1993
24: * The Regents of the University of California. All rights reserved.
25: *
26: * Redistribution and use in source and binary forms, with or without
27: * modification, are permitted provided that the following conditions
28: * are met:
29: * 1. Redistributions of source code must retain the above copyright
30: * notice, this list of conditions and the following disclaimer.
31: * 2. Redistributions in binary form must reproduce the above copyright
32: * notice, this list of conditions and the following disclaimer in the
33: * documentation and/or other materials provided with the distribution.
34: * 3. All advertising materials mentioning features or use of this software
35: * must display the following acknowledgement:
36: * This product includes software developed by the University of
37: * California, Berkeley and its contributors.
38: * 4. Neither the name of the University nor the names of its contributors
39: * may be used to endorse or promote products derived from this software
40: * without specific prior written permission.
41: *
42: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
43: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
44: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
45: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
46: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
47: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
48: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
49: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
50: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
51: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52: * SUCH DAMAGE.
53: *
54: * From: @(#)tcp_usrreq.c 8.2 (Berkeley) 1/3/94
55: */
56:
57: #if ISFB31
58: #include "opt_tcpdebug.h"
59: #endif
60:
61: #include <sys/param.h>
62: #include <sys/systm.h>
63: #include <sys/kernel.h>
64: #include <sys/sysctl.h>
65: #include <sys/mbuf.h>
66: #include <sys/socket.h>
67: #include <sys/socketvar.h>
68: #include <sys/protosw.h>
69:
70: #include <net/if.h>
71: #include <net/route.h>
72:
73: #include <netinet/in.h>
74: #include <netinet/in_systm.h>
75: #include <netinet/in_pcb.h>
76: #include <netinet/in_var.h>
77: #include <netinet/ip_var.h>
78: #include <netinet/tcp.h>
79: #include <netinet/tcp_fsm.h>
80: #include <netinet/tcp_seq.h>
81: #include <netinet/tcp_timer.h>
82: #include <netinet/tcp_var.h>
83: #include <netinet/tcpip.h>
84: #if TCPDEBUG
85: #include <netinet/tcp_debug.h>
86: #endif
87:
88: /*
89: * TCP protocol interface to socket abstraction.
90: */
91: extern char *tcpstates[]; /* XXX ??? */
92:
93: static int tcp_attach __P((struct socket *, struct proc *));
94: static int tcp_connect __P((struct tcpcb *, struct sockaddr *,
95: struct proc *));
96: static struct tcpcb *
97: tcp_disconnect __P((struct tcpcb *));
98: static struct tcpcb *
99: tcp_usrclosed __P((struct tcpcb *));
100:
101: #if TCPDEBUG
102: #define TCPDEBUG0 int ostate
103: #define TCPDEBUG1() ostate = tp ? tp->t_state : 0
104: #define TCPDEBUG2(req) if (tp && (so->so_options & SO_DEBUG)) \
105: tcp_trace(TA_USER, ostate, tp, 0, req)
106: #else
107: #define TCPDEBUG0
108: #define TCPDEBUG1()
109: #define TCPDEBUG2(req)
110: #endif
111:
112: /*
113: * TCP attaches to socket via pru_attach(), reserving space,
114: * and an internet control block.
115: */
116: static int
117: tcp_usr_attach(struct socket *so, int proto, struct proc *p)
118: {
119: int s = splnet();
120: int error;
121: struct inpcb *inp = sotoinpcb(so);
122: struct tcpcb *tp = 0;
123: TCPDEBUG0;
124:
125: TCPDEBUG1();
126: if (inp) {
127: error = EISCONN;
128: goto out;
129: }
130:
131: error = tcp_attach(so, p);
132: if (error)
133: goto out;
134:
135: if ((so->so_options & SO_LINGER) && so->so_linger == 0)
136: so->so_linger = TCP_LINGERTIME * hz;
137: tp = sototcpcb(so);
138: out:
139: TCPDEBUG2(PRU_ATTACH);
140: splx(s);
141: return error;
142: }
143:
144: /*
145: * pru_detach() detaches the TCP protocol from the socket.
146: * If the protocol state is non-embryonic, then can't
147: * do this directly: have to initiate a pru_disconnect(),
148: * which may finish later; embryonic TCB's can just
149: * be discarded here.
150: */
151: static int
152: tcp_usr_detach(struct socket *so)
153: {
154: int s = splnet();
155: int error = 0;
156: struct inpcb *inp = sotoinpcb(so);
157: struct tcpcb *tp;
158: TCPDEBUG0;
159:
160: if (inp == 0) {
161: splx(s);
162: return EINVAL; /* XXX */
163: }
164: tp = intotcpcb(inp);
165: TCPDEBUG1();
166: tp = tcp_disconnect(tp);
167:
168: TCPDEBUG2(PRU_DETACH);
169: splx(s);
170: return error;
171: }
172:
173: #define COMMON_START() TCPDEBUG0; \
174: do { \
175: if (inp == 0) { \
176: splx(s); \
177: return EINVAL; \
178: } \
179: tp = intotcpcb(inp); \
180: TCPDEBUG1(); \
181: } while(0)
182:
183: #define COMMON_END(req) out: TCPDEBUG2(req); splx(s); return error; goto out
184:
185:
186: /*
187: * Give the socket an address.
188: */
189: static int
190: tcp_usr_bind(struct socket *so, struct sockaddr *nam, struct proc *p)
191: {
192: int s = splnet();
193: int error = 0;
194: struct inpcb *inp = sotoinpcb(so);
195: struct tcpcb *tp;
196: struct sockaddr_in *sinp;
197:
198: COMMON_START();
199:
200: /*
201: * Must check for multicast addresses and disallow binding
202: * to them.
203: */
204: sinp = (struct sockaddr_in *)nam;
205: if (sinp->sin_family == AF_INET &&
206: IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
207: error = EAFNOSUPPORT;
208: goto out;
209: }
210: error = in_pcbbind(inp, nam, p);
211: if (error)
212: goto out;
213: COMMON_END(PRU_BIND);
214:
215: }
216:
217: /*
218: * Prepare to accept connections.
219: */
220: static int
221: tcp_usr_listen(struct socket *so, struct proc *p)
222: {
223: int s = splnet();
224: int error = 0;
225: struct inpcb *inp = sotoinpcb(so);
226: struct tcpcb *tp;
227:
228: COMMON_START();
229: if (inp->inp_lport == 0)
230: error = in_pcbbind(inp, (struct sockaddr *)0, p);
231: if (error == 0)
232: tp->t_state = TCPS_LISTEN;
233: COMMON_END(PRU_LISTEN);
234: }
235:
236: /*
237: * Initiate connection to peer.
238: * Create a template for use in transmissions on this connection.
239: * Enter SYN_SENT state, and mark socket as connecting.
240: * Start keep-alive timer, and seed output sequence space.
241: * Send initial segment on connection.
242: */
243: static int
244: tcp_usr_connect(struct socket *so, struct sockaddr *nam, struct proc *p)
245: {
246: int s = splnet();
247: int error = 0;
248: struct inpcb *inp = sotoinpcb(so);
249: struct tcpcb *tp;
250: struct sockaddr_in *sinp;
251:
252: COMMON_START();
253:
254: /*
255: * Must disallow TCP ``connections'' to multicast addresses.
256: */
257: sinp = (struct sockaddr_in *)nam;
258: if (sinp->sin_family == AF_INET
259: && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
260: error = EAFNOSUPPORT;
261: goto out;
262: }
263:
264: if ((error = tcp_connect(tp, nam, p)) != 0)
265: goto out;
266: error = tcp_output(tp);
267: COMMON_END(PRU_CONNECT);
268: }
269:
270: /*
271: * Initiate disconnect from peer.
272: * If connection never passed embryonic stage, just drop;
273: * else if don't need to let data drain, then can just drop anyways,
274: * else have to begin TCP shutdown process: mark socket disconnecting,
275: * drain unread data, state switch to reflect user close, and
276: * send segment (e.g. FIN) to peer. Socket will be really disconnected
277: * when peer sends FIN and acks ours.
278: *
279: * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
280: */
281: static int
282: tcp_usr_disconnect(struct socket *so)
283: {
284: int s = splnet();
285: int error = 0;
286: struct inpcb *inp = sotoinpcb(so);
287: struct tcpcb *tp;
288:
289: COMMON_START();
290: tp = tcp_disconnect(tp);
291: COMMON_END(PRU_DISCONNECT);
292: }
293:
294: /*
295: * Accept a connection. Essentially all the work is
296: * done at higher levels; just return the address
297: * of the peer, storing through addr.
298: */
299: static int
300: tcp_usr_accept(struct socket *so, struct sockaddr **nam)
301: {
302: int s = splnet();
303: int error = 0;
304: struct inpcb *inp = sotoinpcb(so);
305: struct tcpcb *tp;
306:
307: COMMON_START();
308: in_setpeeraddr(so, nam);
309: COMMON_END(PRU_ACCEPT);
310: }
311:
312: /*
313: * Mark the connection as being incapable of further output.
314: */
315: static int
316: tcp_usr_shutdown(struct socket *so)
317: {
318: int s = splnet();
319: int error = 0;
320: struct inpcb *inp = sotoinpcb(so);
321: struct tcpcb *tp;
322:
323: COMMON_START();
324: socantsendmore(so);
325: tp = tcp_usrclosed(tp);
326: if (tp)
327: error = tcp_output(tp);
328: COMMON_END(PRU_SHUTDOWN);
329: }
330:
331: /*
332: * After a receive, possibly send window update to peer.
333: */
334: static int
335: tcp_usr_rcvd(struct socket *so, int flags)
336: {
337: int s = splnet();
338: int error = 0;
339: struct inpcb *inp = sotoinpcb(so);
340: struct tcpcb *tp;
341:
342: COMMON_START();
343: tcp_output(tp);
344: COMMON_END(PRU_RCVD);
345: }
346:
347: /*
348: * Do a send by putting data in output queue and updating urgent
349: * marker if URG set. Possibly send more data.
350: */
351: static int
352: tcp_usr_send(struct socket *so, int flags, struct mbuf *m,
353: struct sockaddr *nam, struct mbuf *control, struct proc *p)
354: {
355: int s = splnet();
356: int error = 0;
357: struct inpcb *inp = sotoinpcb(so);
358: struct tcpcb *tp;
359:
360: COMMON_START();
361: if (control && control->m_len) {
362: m_freem(control); /* XXX shouldn't caller do this??? */
363: if (m)
364: m_freem(m);
365: error = EINVAL;
366: goto out;
367: }
368:
369: if(!(flags & PRUS_OOB)) {
370: sbappend(&so->so_snd, m);
371: if (nam && tp->t_state < TCPS_SYN_SENT) {
372: /*
373: * Do implied connect if not yet connected,
374: * initialize window to default value, and
375: * initialize maxseg/maxopd using peer's cached
376: * MSS.
377: */
378: error = tcp_connect(tp, nam, p);
379: if (error)
380: goto out;
381: tp->snd_wnd = TTCP_CLIENT_SND_WND;
382: tcp_mss(tp, -1);
383: }
384:
385: if (flags & PRUS_EOF) {
386: /*
387: * Close the send side of the connection after
388: * the data is sent.
389: */
390: socantsendmore(so);
391: tp = tcp_usrclosed(tp);
392: }
393: if (tp != NULL) {
394: if (flags & PRUS_MORETOCOME)
395: tp->t_flags |= TF_MORETOCOME;
396: error = tcp_output(tp);
397: if (flags & PRUS_MORETOCOME)
398: tp->t_flags &= ~TF_MORETOCOME;
399: }
400: } else {
401: if (sbspace(&so->so_snd) < -512) {
402: m_freem(m);
403: error = ENOBUFS;
404: goto out;
405: }
406: /*
407: * According to RFC961 (Assigned Protocols),
408: * the urgent pointer points to the last octet
409: * of urgent data. We continue, however,
410: * to consider it to indicate the first octet
411: * of data past the urgent section.
412: * Otherwise, snd_up should be one lower.
413: */
414: sbappend(&so->so_snd, m);
415: if (nam && tp->t_state < TCPS_SYN_SENT) {
416: /*
417: * Do implied connect if not yet connected,
418: * initialize window to default value, and
419: * initialize maxseg/maxopd using peer's cached
420: * MSS.
421: */
422: error = tcp_connect(tp, nam, p);
423: if (error)
424: goto out;
425: tp->snd_wnd = TTCP_CLIENT_SND_WND;
426: tcp_mss(tp, -1);
427: }
428: tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
429: tp->t_force = 1;
430: error = tcp_output(tp);
431: tp->t_force = 0;
432: }
433: COMMON_END((flags & PRUS_OOB) ? PRU_SENDOOB :
434: ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
435: }
436:
437: /*
438: * Abort the TCP.
439: */
440: static int
441: tcp_usr_abort(struct socket *so)
442: {
443: int s = splnet();
444: int error = 0;
445: struct inpcb *inp = sotoinpcb(so);
446: struct tcpcb *tp;
447:
448: COMMON_START();
449: tp = tcp_drop(tp, ECONNABORTED);
450: COMMON_END(PRU_ABORT);
451: }
452:
453: /*
454: * Receive out-of-band data.
455: */
456: static int
457: tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
458: {
459: int s = splnet();
460: int error = 0;
461: struct inpcb *inp = sotoinpcb(so);
462: struct tcpcb *tp;
463:
464: COMMON_START();
465: if ((so->so_oobmark == 0 &&
466: (so->so_state & SS_RCVATMARK) == 0) ||
467: so->so_options & SO_OOBINLINE ||
468: tp->t_oobflags & TCPOOB_HADDATA) {
469: error = EINVAL;
470: goto out;
471: }
472: if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
473: error = EWOULDBLOCK;
474: goto out;
475: }
476: m->m_len = 1;
477: *mtod(m, caddr_t) = tp->t_iobc;
478: if ((flags & MSG_PEEK) == 0)
479: tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
480: COMMON_END(PRU_RCVOOB);
481: }
482:
483: /* xxx - should be const */
484: struct pr_usrreqs tcp_usrreqs = {
485: tcp_usr_abort, tcp_usr_accept, tcp_usr_attach, tcp_usr_bind,
486: tcp_usr_connect, pru_connect2_notsupp, in_control, tcp_usr_detach,
487: tcp_usr_disconnect, tcp_usr_listen, in_setpeeraddr, tcp_usr_rcvd,
488: tcp_usr_rcvoob, tcp_usr_send, pru_sense_null, tcp_usr_shutdown,
489: in_setsockaddr, sosend, soreceive, sopoll
490: };
491:
492: /*
493: * Common subroutine to open a TCP connection to remote host specified
494: * by struct sockaddr_in in mbuf *nam. Call in_pcbbind to assign a local
495: * port number if needed. Call in_pcbladdr to do the routing and to choose
496: * a local host address (interface). If there is an existing incarnation
497: * of the same connection in TIME-WAIT state and if the remote host was
498: * sending CC options and if the connection duration was < MSL, then
499: * truncate the previous TIME-WAIT state and proceed.
500: * Initialize connection parameters and enter SYN-SENT state.
501: */
502: static int
503: tcp_connect(tp, nam, p)
504: register struct tcpcb *tp;
505: struct sockaddr *nam;
506: struct proc *p;
507: {
508: struct inpcb *inp = tp->t_inpcb, *oinp;
509: struct socket *so = inp->inp_socket;
510: struct tcpcb *otp;
511: struct sockaddr_in *sin = (struct sockaddr_in *)nam;
512: struct sockaddr_in *ifaddr;
513: struct rmxp_tao *taop;
514: struct rmxp_tao tao_noncached;
515: int error;
516:
517: if (inp->inp_lport == 0) {
518: error = in_pcbbind(inp, (struct sockaddr *)0, p);
519: if (error)
520: return error;
521: }
522:
523: /*
524: * Cannot simply call in_pcbconnect, because there might be an
525: * earlier incarnation of this same connection still in
526: * TIME_WAIT state, creating an ADDRINUSE error.
527: */
528: error = in_pcbladdr(inp, nam, &ifaddr);
529: if (error)
530: return error;
531: oinp = in_pcblookup_hash(inp->inp_pcbinfo,
532: sin->sin_addr, sin->sin_port,
533: inp->inp_laddr.s_addr != INADDR_ANY ? inp->inp_laddr
534: : ifaddr->sin_addr,
535: inp->inp_lport, 0);
536: if (oinp) {
537: if (oinp != inp && (otp = intotcpcb(oinp)) != NULL &&
538: otp->t_state == TCPS_TIME_WAIT &&
539: otp->t_duration < TCPTV_MSL &&
540: (otp->t_flags & TF_RCVD_CC))
541: otp = tcp_close(otp);
542: else
543: return EADDRINUSE;
544: }
545: if (inp->inp_laddr.s_addr == INADDR_ANY)
546: inp->inp_laddr = ifaddr->sin_addr;
547: inp->inp_faddr = sin->sin_addr;
548: inp->inp_fport = sin->sin_port;
549: in_pcbrehash(inp);
550:
551: tp->t_template = tcp_template(tp);
552: if (tp->t_template == 0) {
553: in_pcbdisconnect(inp);
554: return ENOBUFS;
555: }
556:
557: /* Compute window scaling to request. */
558: while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
559: (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
560: tp->request_r_scale++;
561:
562: soisconnecting(so);
563: tcpstat.tcps_connattempt++;
564: tp->t_state = TCPS_SYN_SENT;
565: tp->t_timer[TCPT_KEEP] = tcp_keepinit;
566: tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
567: tcp_sendseqinit(tp);
568:
569: /*
570: * Generate a CC value for this connection and
571: * check whether CC or CCnew should be used.
572: */
573: if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) {
574: taop = &tao_noncached;
575: bzero(taop, sizeof(*taop));
576: }
577:
578: tp->cc_send = CC_INC(tcp_ccgen);
579: if (taop->tao_ccsent != 0 &&
580: CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
581: taop->tao_ccsent = tp->cc_send;
582: } else {
583: taop->tao_ccsent = 0;
584: tp->t_flags |= TF_SENDCCNEW;
585: }
586:
587: return 0;
588: }
589:
590: /*
591: * The new sockopt interface makes it possible for us to block in the
592: * copyin/out step (if we take a page fault). Taking a page fault at
593: * splnet() is probably a Bad Thing. (Since sockets and pcbs both now
594: * use TSM, there probably isn't any need for this function to run at
595: * splnet() any more. This needs more examination.)
596: */
597: int
598: tcp_ctloutput(so, sopt)
599: struct socket *so;
600: struct sockopt *sopt;
601: {
602: int error, opt, optval, s;
603: struct inpcb *inp;
604: struct tcpcb *tp;
605:
606: error = 0;
607: s = splnet(); /* XXX */
608: inp = sotoinpcb(so);
609: if (inp == NULL) {
610: splx(s);
611: return (ECONNRESET);
612: }
613: if (sopt->sopt_level != IPPROTO_TCP) {
614: error = ip_ctloutput(so, sopt);
615: splx(s);
616: return (error);
617: }
618: tp = intotcpcb(inp);
619:
620: switch (sopt->sopt_dir) {
621: case SOPT_SET:
622: switch (sopt->sopt_name) {
623: case TCP_NODELAY:
624: case TCP_NOOPT:
625: case TCP_NOPUSH:
626: error = sooptcopyin(sopt, &optval, sizeof optval,
627: sizeof optval);
628: if (error)
629: break;
630:
631: switch (sopt->sopt_name) {
632: case TCP_NODELAY:
633: opt = TF_NODELAY;
634: break;
635: case TCP_NOOPT:
636: opt = TF_NOOPT;
637: break;
638: case TCP_NOPUSH:
639: opt = TF_NOPUSH;
640: break;
641: default:
642: opt = 0; /* dead code to fool gcc */
643: break;
644: }
645:
646: if (optval)
647: tp->t_flags |= opt;
648: else
649: tp->t_flags &= ~opt;
650: break;
651:
652: case TCP_MAXSEG:
653: error = sooptcopyin(sopt, &optval, sizeof optval,
654: sizeof optval);
655: if (error)
656: break;
657:
658: if (optval > 0 && optval <= tp->t_maxseg)
659: tp->t_maxseg = optval;
660: else
661: error = EINVAL;
662: break;
663:
664: default:
665: error = ENOPROTOOPT;
666: break;
667: }
668: break;
669:
670: case SOPT_GET:
671: switch (sopt->sopt_name) {
672: case TCP_NODELAY:
673: optval = tp->t_flags & TF_NODELAY;
674: break;
675: case TCP_MAXSEG:
676: optval = tp->t_maxseg;
677: break;
678: case TCP_NOOPT:
679: optval = tp->t_flags & TF_NOOPT;
680: break;
681: case TCP_NOPUSH:
682: optval = tp->t_flags & TF_NOPUSH;
683: break;
684: default:
685: error = ENOPROTOOPT;
686: break;
687: }
688: if (error == 0)
689: error = sooptcopyout(sopt, &optval, sizeof optval);
690: break;
691: }
692: splx(s);
693: return (error);
694: }
695:
696: /*
697: * tcp_sendspace and tcp_recvspace are the default send and receive window
698: * sizes, respectively. These are obsolescent (this information should
699: * be set by the route).
700: */
701: u_long tcp_sendspace = 1024*16;
702: SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace,
703: CTLFLAG_RW, &tcp_sendspace , 0, "");
704: u_long tcp_recvspace = 1024*16;
705: SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace,
706: CTLFLAG_RW, &tcp_recvspace , 0, "");
707:
708: /*
709: * Attach TCP protocol to socket, allocating
710: * internet protocol control block, tcp control block,
711: * bufer space, and entering LISTEN state if to accept connections.
712: */
713: static int
714: tcp_attach(so, p)
715: struct socket *so;
716: struct proc *p;
717: {
718: register struct tcpcb *tp;
719: struct inpcb *inp;
720: int error;
721:
722: if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
723: error = soreserve(so, tcp_sendspace, tcp_recvspace);
724: if (error)
725: return (error);
726: }
727: error = in_pcballoc(so, &tcbinfo, p);
728: if (error)
729: return (error);
730: inp = sotoinpcb(so);
731: tp = tcp_newtcpcb(inp);
732: if (tp == 0) {
733: int nofd = so->so_state & SS_NOFDREF; /* XXX */
734:
735: so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */
736: in_pcbdetach(inp);
737: so->so_state |= nofd;
738: return (ENOBUFS);
739: }
740: tp->t_state = TCPS_CLOSED;
741: return (0);
742: }
743:
744: /*
745: * Initiate (or continue) disconnect.
746: * If embryonic state, just send reset (once).
747: * If in ``let data drain'' option and linger null, just drop.
748: * Otherwise (hard), mark socket disconnecting and drop
749: * current input data; switch states based on user close, and
750: * send segment to peer (with FIN).
751: */
752: static struct tcpcb *
753: tcp_disconnect(tp)
754: register struct tcpcb *tp;
755: {
756: struct socket *so = tp->t_inpcb->inp_socket;
757:
758: if (tp->t_state < TCPS_ESTABLISHED)
759: tp = tcp_close(tp);
760: else if ((so->so_options & SO_LINGER) && so->so_linger == 0)
761: tp = tcp_drop(tp, 0);
762: else {
763: soisdisconnecting(so);
764: sbflush(&so->so_rcv);
765: tp = tcp_usrclosed(tp);
766: if (tp)
767: (void) tcp_output(tp);
768: }
769: return (tp);
770: }
771:
772: /*
773: * User issued close, and wish to trail through shutdown states:
774: * if never received SYN, just forget it. If got a SYN from peer,
775: * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
776: * If already got a FIN from peer, then almost done; go to LAST_ACK
777: * state. In all other cases, have already sent FIN to peer (e.g.
778: * after PRU_SHUTDOWN), and just have to play tedious game waiting
779: * for peer to send FIN or not respond to keep-alives, etc.
780: * We can let the user exit from the close as soon as the FIN is acked.
781: */
782: static struct tcpcb *
783: tcp_usrclosed(tp)
784: register struct tcpcb *tp;
785: {
786:
787: switch (tp->t_state) {
788:
789: case TCPS_CLOSED:
790: case TCPS_LISTEN:
791: tp->t_state = TCPS_CLOSED;
792: tp = tcp_close(tp);
793: break;
794:
795: case TCPS_SYN_SENT:
796: case TCPS_SYN_RECEIVED:
797: tp->t_flags |= TF_NEEDFIN;
798: break;
799:
800: case TCPS_ESTABLISHED:
801: tp->t_state = TCPS_FIN_WAIT_1;
802: break;
803:
804: case TCPS_CLOSE_WAIT:
805: tp->t_state = TCPS_LAST_ACK;
806: break;
807: }
808: if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
809: soisdisconnected(tp->t_inpcb->inp_socket);
810: /* To prevent the connection hanging in FIN_WAIT_2 forever. */
811: if (tp->t_state == TCPS_FIN_WAIT_2)
812: tp->t_timer[TCPT_2MSL] = tcp_maxidle;
813: }
814: return (tp);
815: }
816:
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