1 /*
2  * Copyright (c) 1982, 1986, 1988, 1990, 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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)tcp_subr.c	8.1 (Berkeley) 6/10/93
34  * tcp_subr.c,v 1.5 1994/10/08 22:39:58 phk Exp
35  */
36 
37 /*
38  * Changes and additions relating to SLiRP
39  * Copyright (c) 1995 Danny Gasparovski.
40  *
41  * Please read the file COPYRIGHT for the
42  * terms and conditions of the copyright.
43  */
44 
45 #define WANT_SYS_IOCTL_H
46 #include <slirp.h>
47 
48 /* patchable/settable parameters for tcp */
49 int 	tcp_mssdflt = TCP_MSS;
50 int 	tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
51 int	tcp_do_rfc1323 = 0;	/* Don't do rfc1323 performance enhancements */
52 int	tcp_rcvspace;	/* You may want to change this */
53 int	tcp_sndspace;	/* Keep small if you have an error prone link */
54 
55 /*
56  * Tcp initialization
57  */
58 void
tcp_init()59 tcp_init()
60 {
61 	tcp_iss = 1;		/* wrong */
62 	tcb.so_next = tcb.so_prev = &tcb;
63 
64 	/* tcp_rcvspace = our Window we advertise to the remote */
65 	tcp_rcvspace = TCP_RCVSPACE;
66 	tcp_sndspace = TCP_SNDSPACE;
67 
68 	/* Make sure tcp_sndspace is at least 2*MSS */
69 	if (tcp_sndspace < 2*(min(if_mtu, if_mru) - sizeof(struct tcpiphdr)))
70 		tcp_sndspace = 2*(min(if_mtu, if_mru) - sizeof(struct tcpiphdr));
71 }
72 
73 /*
74  * Create template to be used to send tcp packets on a connection.
75  * Call after host entry created, fills
76  * in a skeletal tcp/ip header, minimizing the amount of work
77  * necessary when the connection is used.
78  */
79 /* struct tcpiphdr * */
80 void
tcp_template(tp)81 tcp_template(tp)
82 	struct tcpcb *tp;
83 {
84 	struct socket *so = tp->t_socket;
85 	register struct tcpiphdr *n = &tp->t_template;
86 
87 	n->ti_next = n->ti_prev = 0;
88 	n->ti_x1 = 0;
89 	n->ti_pr = IPPROTO_TCP;
90 	n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
91 	n->ti_src = so->so_faddr;
92 	n->ti_dst = so->so_laddr;
93 	n->ti_sport = so->so_fport;
94 	n->ti_dport = so->so_lport;
95 
96 	n->ti_seq = 0;
97 	n->ti_ack = 0;
98 	n->ti_x2 = 0;
99 	n->ti_off = 5;
100 	n->ti_flags = 0;
101 	n->ti_win = 0;
102 	n->ti_sum = 0;
103 	n->ti_urp = 0;
104 }
105 
106 /*
107  * Send a single message to the TCP at address specified by
108  * the given TCP/IP header.  If m == 0, then we make a copy
109  * of the tcpiphdr at ti and send directly to the addressed host.
110  * This is used to force keep alive messages out using the TCP
111  * template for a connection tp->t_template.  If flags are given
112  * then we send a message back to the TCP which originated the
113  * segment ti, and discard the mbuf containing it and any other
114  * attached mbufs.
115  *
116  * In any case the ack and sequence number of the transmitted
117  * segment are as specified by the parameters.
118  */
119 void
tcp_respond(tp,ti,m,ack,seq,flags)120 tcp_respond(tp, ti, m, ack, seq, flags)
121 	struct tcpcb *tp;
122 	register struct tcpiphdr *ti;
123 	register struct mbuf *m;
124 	tcp_seq ack, seq;
125 	int flags;
126 {
127 	register int tlen;
128 	int win = 0;
129 
130 	DEBUG_CALL("tcp_respond");
131 	DEBUG_ARG("tp = %lx", (long)tp);
132 	DEBUG_ARG("ti = %lx", (long)ti);
133 	DEBUG_ARG("m = %lx", (long)m);
134 	DEBUG_ARG("ack = %u", ack);
135 	DEBUG_ARG("seq = %u", seq);
136 	DEBUG_ARG("flags = %x", flags);
137 
138 	if (tp)
139 		win = sbspace(&tp->t_socket->so_rcv);
140 	if (m == 0) {
141 		if ((m = m_get()) == NULL)
142 			return;
143 #ifdef TCP_COMPAT_42
144 		tlen = 1;
145 #else
146 		tlen = 0;
147 #endif
148 		m->m_data += if_maxlinkhdr;
149 		*mtod(m, struct tcpiphdr *) = *ti;
150 		ti = mtod(m, struct tcpiphdr *);
151 		flags = TH_ACK;
152 	} else {
153 		/*
154 		 * ti points into m so the next line is just making
155 		 * the mbuf point to ti
156 		 */
157 		m->m_data = (caddr_t)ti;
158 
159 		m->m_len = sizeof (struct tcpiphdr);
160 		tlen = 0;
161 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
162 		xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_int32_t);
163 		xchg(ti->ti_dport, ti->ti_sport, u_int16_t);
164 #undef xchg
165 	}
166 	ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
167 	tlen += sizeof (struct tcpiphdr);
168 	m->m_len = tlen;
169 
170 	ti->ti_next = ti->ti_prev = 0;
171 	ti->ti_x1 = 0;
172 	ti->ti_seq = htonl(seq);
173 	ti->ti_ack = htonl(ack);
174 	ti->ti_x2 = 0;
175 	ti->ti_off = sizeof (struct tcphdr) >> 2;
176 	ti->ti_flags = flags;
177 	if (tp)
178 		ti->ti_win = htons((u_int16_t) (win >> tp->rcv_scale));
179 	else
180 		ti->ti_win = htons((u_int16_t)win);
181 	ti->ti_urp = 0;
182 	ti->ti_sum = 0;
183 	ti->ti_sum = cksum(m, tlen);
184 	((struct ip *)ti)->ip_len = tlen;
185 
186 	if(flags & TH_RST)
187 	  ((struct ip *)ti)->ip_ttl = MAXTTL;
188 	else
189 	  ((struct ip *)ti)->ip_ttl = ip_defttl;
190 
191 	(void) ip_output((struct socket *)0, m);
192 }
193 
194 /*
195  * Create a new TCP control block, making an
196  * empty reassembly queue and hooking it to the argument
197  * protocol control block.
198  */
199 struct tcpcb *
tcp_newtcpcb(so)200 tcp_newtcpcb(so)
201 	struct socket *so;
202 {
203 	register struct tcpcb *tp;
204 
205 	tp = (struct tcpcb *)malloc(sizeof(*tp));
206 	if (tp == NULL)
207 		return ((struct tcpcb *)0);
208 
209 	memset((char *) tp, 0, sizeof(struct tcpcb));
210 	tp->seg_next = tp->seg_prev = (tcpiphdrp_32)tp;
211 	tp->t_maxseg = tcp_mssdflt;
212 
213 	tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0;
214 	tp->t_socket = so;
215 
216 	/*
217 	 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
218 	 * rtt estimate.  Set rttvar so that srtt + 2 * rttvar gives
219 	 * reasonable initial retransmit time.
220 	 */
221 	tp->t_srtt = TCPTV_SRTTBASE;
222 	tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 2;
223 	tp->t_rttmin = TCPTV_MIN;
224 
225 	TCPT_RANGESET(tp->t_rxtcur,
226 	    ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
227 	    TCPTV_MIN, TCPTV_REXMTMAX);
228 
229 	tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
230 	tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
231 	tp->t_state = TCPS_CLOSED;
232 
233 	so->so_tcpcb = tp;
234 
235 	return (tp);
236 }
237 
238 /*
239  * Drop a TCP connection, reporting
240  * the specified error.  If connection is synchronized,
241  * then send a RST to peer.
242  */
tcp_drop(struct tcpcb * tp,int err)243 struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
244 {
245 /* tcp_drop(tp, errno)
246 	register struct tcpcb *tp;
247 	int errno;
248 {
249 */
250 
251 	DEBUG_CALL("tcp_drop");
252 	DEBUG_ARG("tp = %lx", (long)tp);
253 	DEBUG_ARG("errno = %d", errno);
254 
255 	if (TCPS_HAVERCVDSYN(tp->t_state)) {
256 		tp->t_state = TCPS_CLOSED;
257 		(void) tcp_output(tp);
258 		tcpstat.tcps_drops++;
259 	} else
260 		tcpstat.tcps_conndrops++;
261 /*	if (errno == ETIMEDOUT && tp->t_softerror)
262  *		errno = tp->t_softerror;
263  */
264 /*	so->so_error = errno; */
265 	return (tcp_close(tp));
266 }
267 
268 /*
269  * Close a TCP control block:
270  *	discard all space held by the tcp
271  *	discard internet protocol block
272  *	wake up any sleepers
273  */
274 struct tcpcb *
tcp_close(tp)275 tcp_close(tp)
276 	register struct tcpcb *tp;
277 {
278 	register struct tcpiphdr *t;
279 	struct socket *so = tp->t_socket;
280 	register struct mbuf *m;
281 
282 	DEBUG_CALL("tcp_close");
283 	DEBUG_ARG("tp = %lx", (long )tp);
284 
285 	/* free the reassembly queue, if any */
286 	t = (struct tcpiphdr *) tp->seg_next;
287 	while (t != (struct tcpiphdr *)tp) {
288 		t = (struct tcpiphdr *)t->ti_next;
289 		m = (struct mbuf *) REASS_MBUF((struct tcpiphdr *)t->ti_prev);
290 		remque_32((struct tcpiphdr *) t->ti_prev);
291 		m_freem(m);
292 	}
293 	/* It's static */
294 /*	if (tp->t_template)
295  *		(void) m_free(dtom(tp->t_template));
296  */
297 /*	free(tp, M_PCB);  */
298 	free(tp);
299 	so->so_tcpcb = 0;
300 	soisfdisconnected(so);
301 	/* clobber input socket cache if we're closing the cached connection */
302 	if (so == tcp_last_so)
303 		tcp_last_so = &tcb;
304 	close(so->s);
305 	sbfree(&so->so_rcv);
306 	sbfree(&so->so_snd);
307 	sofree(so);
308 	tcpstat.tcps_closed++;
309 	return ((struct tcpcb *)0);
310 }
311 
312 void
tcp_drain()313 tcp_drain()
314 {
315 	/* XXX */
316 }
317 
318 /*
319  * When a source quench is received, close congestion window
320  * to one segment.  We will gradually open it again as we proceed.
321  */
322 
323 #ifdef notdef
324 
325 void
tcp_quench(i,errno)326 tcp_quench(i, errno)
327 
328 	int errno;
329 {
330 	struct tcpcb *tp = intotcpcb(inp);
331 
332 	if (tp)
333 		tp->snd_cwnd = tp->t_maxseg;
334 }
335 
336 #endif /* notdef */
337 
338 /*
339  * TCP protocol interface to socket abstraction.
340  */
341 
342 /*
343  * User issued close, and wish to trail through shutdown states:
344  * if never received SYN, just forget it.  If got a SYN from peer,
345  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
346  * If already got a FIN from peer, then almost done; go to LAST_ACK
347  * state.  In all other cases, have already sent FIN to peer (e.g.
348  * after PRU_SHUTDOWN), and just have to play tedious game waiting
349  * for peer to send FIN or not respond to keep-alives, etc.
350  * We can let the user exit from the close as soon as the FIN is acked.
351  */
352 void
tcp_sockclosed(tp)353 tcp_sockclosed(tp)
354 	struct tcpcb *tp;
355 {
356 
357 	DEBUG_CALL("tcp_sockclosed");
358 	DEBUG_ARG("tp = %lx", (long)tp);
359 
360 	switch (tp->t_state) {
361 
362 	case TCPS_CLOSED:
363 	case TCPS_LISTEN:
364 	case TCPS_SYN_SENT:
365 		tp->t_state = TCPS_CLOSED;
366 		tp = tcp_close(tp);
367 		break;
368 
369 	case TCPS_SYN_RECEIVED:
370 	case TCPS_ESTABLISHED:
371 		tp->t_state = TCPS_FIN_WAIT_1;
372 		break;
373 
374 	case TCPS_CLOSE_WAIT:
375 		tp->t_state = TCPS_LAST_ACK;
376 		break;
377 	}
378 /*	soisfdisconnecting(tp->t_socket); */
379 	if (tp && tp->t_state >= TCPS_FIN_WAIT_2)
380 		soisfdisconnected(tp->t_socket);
381 	if (tp)
382 		tcp_output(tp);
383 }
384 
385 /*
386  * Connect to a host on the Internet
387  * Called by tcp_input
388  * Only do a connect, the tcp fields will be set in tcp_input
389  * return 0 if there's a result of the connect,
390  * else return -1 means we're still connecting
391  * The return value is almost always -1 since the socket is
392  * nonblocking.  Connect returns after the SYN is sent, and does
393  * not wait for ACK+SYN.
394  */
tcp_fconnect(so)395 int tcp_fconnect(so)
396      struct socket *so;
397 {
398   int ret=0;
399 
400   DEBUG_CALL("tcp_fconnect");
401   DEBUG_ARG("so = %lx", (long )so);
402 
403   if( (ret=so->s=socket(AF_INET,SOCK_STREAM,0)) >= 0) {
404     int opt, s=so->s;
405     struct sockaddr_in addr;
406 
407     fd_nonblock(s);
408     opt = 1;
409     setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(opt ));
410     opt = 1;
411     setsockopt(s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(opt ));
412 
413     addr.sin_family = AF_INET;
414     if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) {
415       /* It's an alias */
416       switch(ntohl(so->so_faddr.s_addr) & 0xff) {
417       case CTL_DNS:
418 	addr.sin_addr = dns_addr;
419 	break;
420       case CTL_ALIAS:
421       default:
422 	addr.sin_addr = loopback_addr;
423 	break;
424       }
425     } else
426       addr.sin_addr = so->so_faddr;
427     addr.sin_port = so->so_fport;
428 
429     DEBUG_MISC((dfd, " connect()ing, addr.sin_port=%d, "
430 		"addr.sin_addr.s_addr=%.16s\n",
431 		ntohs(addr.sin_port), inet_ntoa(addr.sin_addr)));
432     /* We don't care what port we get */
433     ret = connect(s,(struct sockaddr *)&addr,sizeof (addr));
434 
435     /*
436      * If it's not in progress, it failed, so we just return 0,
437      * without clearing SS_NOFDREF
438      */
439     soisfconnecting(so);
440   }
441 
442   return(ret);
443 }
444 
445 /*
446  * Accept the socket and connect to the local-host
447  *
448  * We have a problem. The correct thing to do would be
449  * to first connect to the local-host, and only if the
450  * connection is accepted, then do an accept() here.
451  * But, a) we need to know who's trying to connect
452  * to the socket to be able to SYN the local-host, and
453  * b) we are already connected to the foreign host by
454  * the time it gets to accept(), so... We simply accept
455  * here and SYN the local-host.
456  */
457 void
tcp_connect(inso)458 tcp_connect(inso)
459 	struct socket *inso;
460 {
461 	struct socket *so;
462 	struct sockaddr_in addr;
463 	int addrlen = sizeof(struct sockaddr_in);
464 	struct tcpcb *tp;
465 	int s, opt;
466 
467 	DEBUG_CALL("tcp_connect");
468 	DEBUG_ARG("inso = %lx", (long)inso);
469 
470 	/*
471 	 * If it's an SS_ACCEPTONCE socket, no need to socreate()
472 	 * another socket, just use the accept() socket.
473 	 */
474 	if (inso->so_state & SS_FACCEPTONCE) {
475 		/* FACCEPTONCE already have a tcpcb */
476 		so = inso;
477 	} else {
478 		if ((so = socreate()) == NULL) {
479 			/* If it failed, get rid of the pending connection */
480 			close(accept(inso->s,(struct sockaddr *)&addr,&addrlen));
481 			return;
482 		}
483 		if (tcp_attach(so) < 0) {
484 			free(so); /* NOT sofree */
485 			return;
486 		}
487 		so->so_laddr = inso->so_laddr;
488 		so->so_lport = inso->so_lport;
489 	}
490 
491 	(void) tcp_mss(sototcpcb(so), 0);
492 
493 	if ((s = accept(inso->s,(struct sockaddr *)&addr,&addrlen)) < 0) {
494 		tcp_close(sototcpcb(so)); /* This will sofree() as well */
495 		return;
496 	}
497 	fd_nonblock(s);
498 	opt = 1;
499 	setsockopt(s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
500 	opt = 1;
501 	setsockopt(s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int));
502 
503 	so->so_fport = addr.sin_port;
504 	so->so_faddr = addr.sin_addr;
505 	/* Translate connections from localhost to the real hostname */
506 	if (so->so_faddr.s_addr == 0 || so->so_faddr.s_addr == loopback_addr.s_addr)
507 	   so->so_faddr = our_addr;
508 
509 	/* Close the accept() socket, set right state */
510 	if (inso->so_state & SS_FACCEPTONCE) {
511 		close(so->s); /* If we only accept once, close the accept() socket */
512 		so->so_state = SS_NOFDREF; /* Don't select it yet, even though we have an FD */
513 					   /* if it's not FACCEPTONCE, it's already NOFDREF */
514 	}
515 	so->s = s;
516 
517 	so->so_iptos = tcp_tos(so);
518 	tp = sototcpcb(so);
519 
520 	tcp_template(tp);
521 
522 	/* Compute window scaling to request.  */
523 /*	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
524  *		(TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
525  *		tp->request_r_scale++;
526  */
527 
528 /*	soisconnecting(so); */ /* NOFDREF used instead */
529 	tcpstat.tcps_connattempt++;
530 
531 	tp->t_state = TCPS_SYN_SENT;
532 	tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
533 	tp->iss = tcp_iss;
534 	tcp_iss += TCP_ISSINCR/2;
535 	tcp_sendseqinit(tp);
536 	tcp_output(tp);
537 }
538 
539 /*
540  * Attach a TCPCB to a socket.
541  */
542 int
tcp_attach(so)543 tcp_attach(so)
544 	struct socket *so;
545 {
546 	if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
547 	   return -1;
548 
549 	insque(so, &tcb);
550 
551 	return 0;
552 }
553 
554 /*
555  * Set the socket's type of service field
556  */
557 struct tos_t tcptos[] = {
558 	  {0, 20, IPTOS_THROUGHPUT, 0},	/* ftp data */
559 	  {21, 21, IPTOS_LOWDELAY,  EMU_FTP},	/* ftp control */
560 	  {0, 23, IPTOS_LOWDELAY, 0},	/* telnet */
561 	  {0, 80, IPTOS_THROUGHPUT, 0},	/* WWW */
562 	  {0, 513, IPTOS_LOWDELAY, EMU_RLOGIN|EMU_NOCONNECT},	/* rlogin */
563 	  {0, 514, IPTOS_LOWDELAY, EMU_RSH|EMU_NOCONNECT},	/* shell */
564 	  {0, 544, IPTOS_LOWDELAY, EMU_KSH},		/* kshell */
565 	  {0, 543, IPTOS_LOWDELAY, 0},	/* klogin */
566 	  {0, 6667, IPTOS_THROUGHPUT, EMU_IRC},	/* IRC */
567 	  {0, 6668, IPTOS_THROUGHPUT, EMU_IRC},	/* IRC undernet */
568 	  {0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
569 	  {0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
570 	  {0, 0, 0, 0}
571 };
572 
573 struct emu_t *tcpemu = 0;
574 
575 /*
576  * Return TOS according to the above table
577  */
578 u_int8_t
tcp_tos(so)579 tcp_tos(so)
580 	struct socket *so;
581 {
582 	int i = 0;
583 	struct emu_t *emup;
584 
585 	while(tcptos[i].tos) {
586 		if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
587 		    (tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
588 			so->so_emu = tcptos[i].emu;
589 			return tcptos[i].tos;
590 		}
591 		i++;
592 	}
593 
594 	/* Nope, lets see if there's a user-added one */
595 	for (emup = tcpemu; emup; emup = emup->next) {
596 		if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
597 		    (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
598 			so->so_emu = emup->emu;
599 			return emup->tos;
600 		}
601 	}
602 
603 	return 0;
604 }
605 
606 int do_echo = -1;
607 
608 /*
609  * Emulate programs that try and connect to us
610  * This includes ftp (the data connection is
611  * initiated by the server) and IRC (DCC CHAT and
612  * DCC SEND) for now
613  *
614  * NOTE: It's possible to crash SLiRP by sending it
615  * unstandard strings to emulate... if this is a problem,
616  * more checks are needed here
617  *
618  * XXX Assumes the whole command came in one packet
619  *
620  * XXX Some ftp clients will have their TOS set to
621  * LOWDELAY and so Nagel will kick in.  Because of this,
622  * we'll get the first letter, followed by the rest, so
623  * we simply scan for ORT instead of PORT...
624  * DCC doesn't have this problem because there's other stuff
625  * in the packet before the DCC command.
626  *
627  * Return 1 if the mbuf m is still valid and should be
628  * sbappend()ed
629  *
630  * NOTE: if you return 0 you MUST m_free() the mbuf!
631  */
632 int
tcp_emu(so,m)633 tcp_emu(so, m)
634 	struct socket *so;
635 	struct mbuf *m;
636 {
637 	u_int n1, n2, n3, n4, n5, n6;
638 	char buff[256];
639 	u_int32_t laddr;
640 	u_int lport;
641 	char *bptr;
642 
643 	DEBUG_CALL("tcp_emu");
644 	DEBUG_ARG("so = %lx", (long)so);
645 	DEBUG_ARG("m = %lx", (long)m);
646 
647 	switch(so->so_emu) {
648 		int x, i;
649 
650 	 case EMU_IDENT:
651 		/*
652 		 * Identification protocol as per rfc-1413
653 		 */
654 
655 		{
656 			struct socket *tmpso;
657 			struct sockaddr_in addr;
658 			int addrlen = sizeof(struct sockaddr_in);
659 			struct sbuf *so_rcv = &so->so_rcv;
660 
661 			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
662 			so_rcv->sb_wptr += m->m_len;
663 			so_rcv->sb_rptr += m->m_len;
664 			m->m_data[m->m_len] = 0; /* NULL terminate */
665 			if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
666 				if (sscanf(so_rcv->sb_data, "%d%*[ ,]%d", &n1, &n2) == 2) {
667 					HTONS(n1);
668 					HTONS(n2);
669 					/* n2 is the one on our host */
670 					for (tmpso = tcb.so_next; tmpso != &tcb; tmpso = tmpso->so_next) {
671 						if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
672 						    tmpso->so_lport == n2 &&
673 						    tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
674 						    tmpso->so_fport == n1) {
675 							if (getsockname(tmpso->s,
676 								(struct sockaddr *)&addr, &addrlen) == 0)
677 							   n2 = ntohs(addr.sin_port);
678 							break;
679 						}
680 					}
681 				}
682 				so_rcv->sb_cc = sprintf(so_rcv->sb_data, "%d,%d\r\n", n1, n2);
683 				so_rcv->sb_rptr = so_rcv->sb_data;
684 				so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
685 			}
686 			m_free(m);
687 			return 0;
688 		}
689 
690 #if 0
691 	 case EMU_RLOGIN:
692 		/*
693 		 * Rlogin emulation
694 		 * First we accumulate all the initial option negotiation,
695 		 * then fork_exec() rlogin according to the  options
696 		 */
697 		{
698 			int i, i2, n;
699 			char *ptr;
700 			char args[100];
701 			char term[100];
702 			struct sbuf *so_snd = &so->so_snd;
703 			struct sbuf *so_rcv = &so->so_rcv;
704 
705 			/* First check if they have a priveladged port, or too much data has arrived */
706 			if (ntohs(so->so_lport) > 1023 || ntohs(so->so_lport) < 512 ||
707 			    (m->m_len + so_rcv->sb_wptr) > (so_rcv->sb_data + so_rcv->sb_datalen)) {
708 				memcpy(so_snd->sb_wptr, "Permission denied\n", 18);
709 				so_snd->sb_wptr += 18;
710 				so_snd->sb_cc += 18;
711 				tcp_sockclosed(sototcpcb(so));
712 				m_free(m);
713 				return 0;
714 			}
715 
716 			/* Append the current data */
717 			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
718 			so_rcv->sb_wptr += m->m_len;
719 			so_rcv->sb_rptr += m->m_len;
720 			m_free(m);
721 
722 			/*
723 			 * Check if we have all the initial options,
724 			 * and build argument list to rlogin while we're here
725 			 */
726 			n = 0;
727 			ptr = so_rcv->sb_data;
728 			args[0] = 0;
729 			term[0] = 0;
730 			while (ptr < so_rcv->sb_wptr) {
731 				if (*ptr++ == 0) {
732 					n++;
733 					if (n == 2) {
734 						sprintf(args, "rlogin -l %s %s",
735 							ptr, inet_ntoa(so->so_faddr));
736 					} else if (n == 3) {
737 						i2 = so_rcv->sb_wptr - ptr;
738 						for (i = 0; i < i2; i++) {
739 							if (ptr[i] == '/') {
740 								ptr[i] = 0;
741 #ifdef HAVE_SETENV
742 								sprintf(term, "%s", ptr);
743 #else
744 								sprintf(term, "TERM=%s", ptr);
745 #endif
746 								ptr[i] = '/';
747 								break;
748 							}
749 						}
750 					}
751 				}
752 			}
753 
754 			if (n != 4)
755 			   return 0;
756 
757 			/* We have it, set our term variable and fork_exec() */
758 #ifdef HAVE_SETENV
759 			setenv("TERM", term, 1);
760 #else
761 			putenv(term);
762 #endif
763 			fork_exec(so, args, 2);
764 			term[0] = 0;
765 			so->so_emu = 0;
766 
767 			/* And finally, send the client a 0 character */
768 			so_snd->sb_wptr[0] = 0;
769 			so_snd->sb_wptr++;
770 			so_snd->sb_cc++;
771 
772 			return 0;
773 		}
774 
775 	 case EMU_RSH:
776 		/*
777 		 * rsh emulation
778 		 * First we accumulate all the initial option negotiation,
779 		 * then rsh_exec() rsh according to the  options
780 		 */
781 		{
782 			int  n;
783 			char *ptr;
784 			char *user;
785 			char *args;
786 			struct sbuf *so_snd = &so->so_snd;
787 			struct sbuf *so_rcv = &so->so_rcv;
788 
789 			/* First check if they have a priveladged port, or too much data has arrived */
790 			if (ntohs(so->so_lport) > 1023 || ntohs(so->so_lport) < 512 ||
791 			    (m->m_len + so_rcv->sb_wptr) > (so_rcv->sb_data + so_rcv->sb_datalen)) {
792 				memcpy(so_snd->sb_wptr, "Permission denied\n", 18);
793 				so_snd->sb_wptr += 18;
794 				so_snd->sb_cc += 18;
795 				tcp_sockclosed(sototcpcb(so));
796 				m_free(m);
797 				return 0;
798 			}
799 
800 			/* Append the current data */
801 			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
802 			so_rcv->sb_wptr += m->m_len;
803 			so_rcv->sb_rptr += m->m_len;
804 			m_free(m);
805 
806 			/*
807 			 * Check if we have all the initial options,
808 			 * and build argument list to rlogin while we're here
809 			 */
810 			n = 0;
811 			ptr = so_rcv->sb_data;
812 			user="";
813 			args="";
814 			if (so->extra==NULL) {
815 				struct socket *ns;
816 				struct tcpcb* tp;
817 				int port=atoi(ptr);
818 				if (port <= 0) return 0;
819                 if (port > 1023 || port < 512) {
820                   memcpy(so_snd->sb_wptr, "Permission denied\n", 18);
821                   so_snd->sb_wptr += 18;
822                   so_snd->sb_cc += 18;
823                   tcp_sockclosed(sototcpcb(so));
824                   return 0;
825                 }
826 				if ((ns=socreate()) == NULL)
827                   return 0;
828 				if (tcp_attach(ns)<0) {
829                   free(ns);
830                   return 0;
831 				}
832 
833 				ns->so_laddr=so->so_laddr;
834 				ns->so_lport=htons(port);
835 
836 				(void) tcp_mss(sototcpcb(ns), 0);
837 
838 				ns->so_faddr=so->so_faddr;
839 				ns->so_fport=htons(IPPORT_RESERVED-1); /* Use a fake port. */
840 
841 				if (ns->so_faddr.s_addr == 0 ||
842 					ns->so_faddr.s_addr == loopback_addr.s_addr)
843                   ns->so_faddr = our_addr;
844 
845 				ns->so_iptos = tcp_tos(ns);
846 				tp = sototcpcb(ns);
847 
848 				tcp_template(tp);
849 
850 				/* Compute window scaling to request.  */
851 				/*	while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
852 				 *		(TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
853 				 *		tp->request_r_scale++;
854 				 */
855 
856                 /*soisfconnecting(ns);*/
857 
858 				tcpstat.tcps_connattempt++;
859 
860 				tp->t_state = TCPS_SYN_SENT;
861 				tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
862 				tp->iss = tcp_iss;
863 				tcp_iss += TCP_ISSINCR/2;
864 				tcp_sendseqinit(tp);
865 				tcp_output(tp);
866 				so->extra=ns;
867 			}
868 			while (ptr < so_rcv->sb_wptr) {
869               if (*ptr++ == 0) {
870                 n++;
871                 if (n == 2) {
872                   user=ptr;
873                 } else if (n == 3) {
874                   args=ptr;
875                 }
876               }
877 			}
878 
879 			if (n != 4)
880               return 0;
881 
882 			rsh_exec(so,so->extra, user, inet_ntoa(so->so_faddr), args);
883 			so->so_emu = 0;
884 			so->extra=NULL;
885 
886 			/* And finally, send the client a 0 character */
887 			so_snd->sb_wptr[0] = 0;
888 			so_snd->sb_wptr++;
889 			so_snd->sb_cc++;
890 
891 			return 0;
892 		}
893 
894 	 case EMU_CTL:
895 		{
896 			int num;
897 			struct sbuf *so_snd = &so->so_snd;
898 			struct sbuf *so_rcv = &so->so_rcv;
899 
900 			/*
901 			 * If there is binary data here, we save it in so->so_m
902 			 */
903 			if (!so->so_m) {
904 			  int rxlen;
905 			  char *rxdata;
906 			  rxdata=mtod(m, char *);
907 			  for (rxlen=m->m_len; rxlen; rxlen--) {
908 			    if (*rxdata++ & 0x80) {
909 			      so->so_m = m;
910 			      return 0;
911 			    }
912 			  }
913 			} /* if(so->so_m==NULL) */
914 
915 			/*
916 			 * Append the line
917 			 */
918 			sbappendsb(so_rcv, m);
919 
920 			/* To avoid going over the edge of the buffer, we reset it */
921 			if (so_snd->sb_cc == 0)
922 			   so_snd->sb_wptr = so_snd->sb_rptr = so_snd->sb_data;
923 
924 			/*
925 			 * A bit of a hack:
926 			 * If the first packet we get here is 1 byte long, then it
927 			 * was done in telnet character mode, therefore we must echo
928 			 * the characters as they come.  Otherwise, we echo nothing,
929 			 * because in linemode, the line is already echoed
930 			 * XXX two or more control connections won't work
931 			 */
932 			if (do_echo == -1) {
933 				if (m->m_len == 1) do_echo = 1;
934 				else do_echo = 0;
935 			}
936 			if (do_echo) {
937 			  sbappendsb(so_snd, m);
938 			  m_free(m);
939 			  tcp_output(sototcpcb(so)); /* XXX */
940 			} else
941 			  m_free(m);
942 
943 			num = 0;
944 			while (num < so->so_rcv.sb_cc) {
945 				if (*(so->so_rcv.sb_rptr + num) == '\n' ||
946 				    *(so->so_rcv.sb_rptr + num) == '\r') {
947 					int n;
948 
949 					*(so_rcv->sb_rptr + num) = 0;
950 					if (ctl_password && !ctl_password_ok) {
951 						/* Need a password */
952 						if (sscanf(so_rcv->sb_rptr, "pass %256s", buff) == 1) {
953 							if (strcmp(buff, ctl_password) == 0) {
954 								ctl_password_ok = 1;
955 								n = sprintf(so_snd->sb_wptr,
956 									    "Password OK.\r\n");
957 								goto do_prompt;
958 							}
959 						}
960 						n = sprintf(so_snd->sb_wptr,
961 					 "Error: Password required, log on with \"pass PASSWORD\"\r\n");
962 						goto do_prompt;
963 					}
964 					cfg_quitting = 0;
965 					n = do_config(so_rcv->sb_rptr, so, PRN_SPRINTF);
966 					if (!cfg_quitting) {
967 						/* Register the printed data */
968 do_prompt:
969 						so_snd->sb_cc += n;
970 						so_snd->sb_wptr += n;
971 						/* Add prompt */
972 						n = sprintf(so_snd->sb_wptr, "Slirp> ");
973 						so_snd->sb_cc += n;
974 						so_snd->sb_wptr += n;
975 					}
976 					/* Drop so_rcv data */
977 					so_rcv->sb_cc = 0;
978 					so_rcv->sb_wptr = so_rcv->sb_rptr = so_rcv->sb_data;
979 					tcp_output(sototcpcb(so)); /* Send the reply */
980 				}
981 				num++;
982 			}
983 			return 0;
984 		}
985 #endif
986         case EMU_FTP: /* ftp */
987 		*(m->m_data+m->m_len) = 0; /* NULL terminate for strstr */
988 		if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
989 			/*
990 			 * Need to emulate the PORT command
991 			 */
992 			x = sscanf(bptr, "ORT %d,%d,%d,%d,%d,%d\r\n%256[^\177]",
993 				   &n1, &n2, &n3, &n4, &n5, &n6, buff);
994 			if (x < 6)
995 			   return 1;
996 
997 			laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
998 			lport = htons((n5 << 8) | (n6));
999 
1000 			if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
1001 			   return 1;
1002 
1003 			n6 = ntohs(so->so_fport);
1004 
1005 			n5 = (n6 >> 8) & 0xff;
1006 			n6 &= 0xff;
1007 
1008 			laddr = ntohl(so->so_faddr.s_addr);
1009 
1010 			n1 = ((laddr >> 24) & 0xff);
1011 			n2 = ((laddr >> 16) & 0xff);
1012 			n3 = ((laddr >> 8)  & 0xff);
1013 			n4 =  (laddr & 0xff);
1014 
1015 			m->m_len = bptr - m->m_data; /* Adjust length */
1016 			m->m_len += sprintf(bptr,"ORT %d,%d,%d,%d,%d,%d\r\n%s",
1017 					    n1, n2, n3, n4, n5, n6, x==7?buff:"");
1018 			return 1;
1019 		} else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
1020 			/*
1021 			 * Need to emulate the PASV response
1022 			 */
1023 			x = sscanf(bptr, "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%256[^\177]",
1024 				   &n1, &n2, &n3, &n4, &n5, &n6, buff);
1025 			if (x < 6)
1026 			   return 1;
1027 
1028 			laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
1029 			lport = htons((n5 << 8) | (n6));
1030 
1031 			if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
1032 			   return 1;
1033 
1034 			n6 = ntohs(so->so_fport);
1035 
1036 			n5 = (n6 >> 8) & 0xff;
1037 			n6 &= 0xff;
1038 
1039 			laddr = ntohl(so->so_faddr.s_addr);
1040 
1041 			n1 = ((laddr >> 24) & 0xff);
1042 			n2 = ((laddr >> 16) & 0xff);
1043 			n3 = ((laddr >> 8)  & 0xff);
1044 			n4 =  (laddr & 0xff);
1045 
1046 			m->m_len = bptr - m->m_data; /* Adjust length */
1047 			m->m_len += sprintf(bptr,"27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
1048 					    n1, n2, n3, n4, n5, n6, x==7?buff:"");
1049 
1050 			return 1;
1051 		}
1052 
1053 		return 1;
1054 
1055 	 case EMU_KSH:
1056 		/*
1057 		 * The kshell (Kerberos rsh) and shell services both pass
1058 		 * a local port port number to carry signals to the server
1059 		 * and stderr to the client.  It is passed at the beginning
1060 		 * of the connection as a NUL-terminated decimal ASCII string.
1061 		 */
1062 		so->so_emu = 0;
1063 		for (lport = 0, i = 0; i < m->m_len-1; ++i) {
1064 			if (m->m_data[i] < '0' || m->m_data[i] > '9')
1065 				return 1;       /* invalid number */
1066 			lport *= 10;
1067 			lport += m->m_data[i] - '0';
1068 		}
1069 		if (m->m_data[m->m_len-1] == '\0' && lport != 0 &&
1070 		    (so = solisten(0, so->so_laddr.s_addr, htons(lport), SS_FACCEPTONCE)) != NULL)
1071 			m->m_len = sprintf(m->m_data, "%d", ntohs(so->so_fport))+1;
1072 		return 1;
1073 
1074 	 case EMU_IRC:
1075 		/*
1076 		 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
1077 		 */
1078 		*(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
1079 		if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
1080 			 return 1;
1081 
1082 		/* The %256s is for the broken mIRC */
1083 		if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
1084 			if ((so = solisten(0, htonl(laddr), htons(lport), SS_FACCEPTONCE)) == NULL)
1085 				return 1;
1086 
1087 			m->m_len = bptr - m->m_data; /* Adjust length */
1088 			m->m_len += sprintf(bptr, "DCC CHAT chat %lu %u%c\n",
1089 			     (unsigned long)ntohl(so->so_faddr.s_addr),
1090 			     ntohs(so->so_fport), 1);
1091 		} else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
1092 			if ((so = solisten(0, htonl(laddr), htons(lport), SS_FACCEPTONCE)) == NULL)
1093 				return 1;
1094 
1095 			m->m_len = bptr - m->m_data; /* Adjust length */
1096 			m->m_len += sprintf(bptr, "DCC SEND %s %lu %u %u%c\n",
1097 			      buff, (unsigned long)ntohl(so->so_faddr.s_addr),
1098 			      ntohs(so->so_fport), n1, 1);
1099 		} else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
1100 			if ((so = solisten(0, htonl(laddr), htons(lport), SS_FACCEPTONCE)) == NULL)
1101 				return 1;
1102 
1103 			m->m_len = bptr - m->m_data; /* Adjust length */
1104 			m->m_len += sprintf(bptr, "DCC MOVE %s %lu %u %u%c\n",
1105 			      buff, (unsigned long)ntohl(so->so_faddr.s_addr),
1106 			      ntohs(so->so_fport), n1, 1);
1107 		}
1108 		return 1;
1109 
1110 	 case EMU_REALAUDIO:
1111                 /*
1112 		 * RealAudio emulation - JP. We must try to parse the incoming
1113 		 * data and try to find the two characters that contain the
1114 		 * port number. Then we redirect an udp port and replace the
1115 		 * number with the real port we got.
1116 		 *
1117 		 * The 1.0 beta versions of the player are not supported
1118 		 * any more.
1119 		 *
1120 		 * A typical packet for player version 1.0 (release version):
1121 		 *
1122 		 * 0000:50 4E 41 00 05
1123 		 * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 .....�..g�l�c..P
1124 		 * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
1125 		 * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
1126 		 * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
1127 		 *
1128 		 * Now the port number 0x1BD7 is found at offset 0x04 of the
1129 		 * Now the port number 0x1BD7 is found at offset 0x04 of the
1130 		 * second packet. This time we received five bytes first and
1131 		 * then the rest. You never know how many bytes you get.
1132 		 *
1133 		 * A typical packet for player version 2.0 (beta):
1134 		 *
1135 		 * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA...........�.
1136 		 * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux�c..Win2.0.0
1137 		 * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
1138 		 * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
1139 		 * 0040:65 2E 72 61 79 53 00 00 06 36 42                e.rayS...6B
1140 		 *
1141 		 * Port number 0x1BC1 is found at offset 0x0d.
1142 		 *
1143 		 * This is just a horrible switch statement. Variable ra tells
1144 		 * us where we're going.
1145 		 */
1146 
1147 		bptr = m->m_data;
1148 		while (bptr < m->m_data + m->m_len) {
1149 			u_short p;
1150 			static int ra = 0;
1151 			char ra_tbl[4];
1152 
1153 			ra_tbl[0] = 0x50;
1154 			ra_tbl[1] = 0x4e;
1155 			ra_tbl[2] = 0x41;
1156 			ra_tbl[3] = 0;
1157 
1158 			switch (ra) {
1159 			 case 0:
1160 			 case 2:
1161 			 case 3:
1162 				if (*bptr++ != ra_tbl[ra]) {
1163 					ra = 0;
1164 					continue;
1165 				}
1166 				break;
1167 
1168 			 case 1:
1169 				/*
1170 				 * We may get 0x50 several times, ignore them
1171 				 */
1172 				if (*bptr == 0x50) {
1173 					ra = 1;
1174 					bptr++;
1175 					continue;
1176 				} else if (*bptr++ != ra_tbl[ra]) {
1177 					ra = 0;
1178 					continue;
1179 				}
1180 				break;
1181 
1182 			 case 4:
1183 				/*
1184 				 * skip version number
1185 				 */
1186 				bptr++;
1187 				break;
1188 
1189 			 case 5:
1190 				/*
1191 				 * The difference between versions 1.0 and
1192 				 * 2.0 is here. For future versions of
1193 				 * the player this may need to be modified.
1194 				 */
1195 				if (*(bptr + 1) == 0x02)
1196 				   bptr += 8;
1197 				else
1198 				   bptr += 4;
1199 				break;
1200 
1201 			 case 6:
1202 				/* This is the field containing the port
1203 				 * number that RA-player is listening to.
1204 				 */
1205 				lport = (((u_char*)bptr)[0] << 8)
1206 				+ ((u_char *)bptr)[1];
1207 				if (lport < 6970)
1208 				   lport += 256;   /* don't know why */
1209 				if (lport < 6970 || lport > 7170)
1210 				   return 1;       /* failed */
1211 
1212 				/* try to get udp port between 6970 - 7170 */
1213 				for (p = 6970; p < 7071; p++) {
1214 					if (udp_listen( htons(p),
1215 						       so->so_laddr.s_addr,
1216 						       htons(lport),
1217 						       SS_FACCEPTONCE)) {
1218 						break;
1219 					}
1220 				}
1221 				if (p == 7071)
1222 				   p = 0;
1223 				*(u_char *)bptr++ = (p >> 8) & 0xff;
1224 				*(u_char *)bptr++ = p & 0xff;
1225 				ra = 0;
1226 				return 1;   /* port redirected, we're done */
1227 				break;
1228 
1229 			 default:
1230 				ra = 0;
1231 			}
1232 			ra++;
1233 		}
1234 		return 1;
1235 
1236 	 default:
1237 		/* Ooops, not emulated, won't call tcp_emu again */
1238 		so->so_emu = 0;
1239 		return 1;
1240 	}
1241 }
1242 
1243 /*
1244  * Do misc. config of SLiRP while its running.
1245  * Return 0 if this connections is to be closed, 1 otherwise,
1246  * return 2 if this is a command-line connection
1247  */
1248 int
tcp_ctl(so)1249 tcp_ctl(so)
1250 	struct socket *so;
1251 {
1252 #if 0
1253 	struct sbuf *sb = &so->so_snd;
1254 	int command;
1255  	struct ex_list *ex_ptr;
1256 	int do_pty;
1257 	struct socket *tmpso;
1258 
1259 	DEBUG_CALL("tcp_ctl");
1260 	DEBUG_ARG("so = %lx", (long )so);
1261 
1262 	/*
1263 	 * Check if they're authorised
1264 	 */
1265 	if (ctl_addr.s_addr && (ctl_addr.s_addr == -1 || (so->so_laddr.s_addr != ctl_addr.s_addr))) {
1266 		sb->sb_cc = sprintf(sb->sb_wptr,"Error: Permission denied.\r\n");
1267 		sb->sb_wptr += sb->sb_cc;
1268 		return 0;
1269 	}
1270 
1271 	command = (ntohl(so->so_faddr.s_addr) & 0xff);
1272 
1273 	switch(command) {
1274 	default: /* Check for exec's */
1275 
1276 		/*
1277 		 * Check if it's pty_exec
1278 		 */
1279 		for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
1280 			if (ex_ptr->ex_fport == so->so_fport &&
1281 			    command == ex_ptr->ex_addr) {
1282 				do_pty = ex_ptr->ex_pty;
1283 				goto do_exec;
1284 			}
1285 		}
1286 
1287 		/*
1288 		 * Nothing bound..
1289 		 */
1290 		/* tcp_fconnect(so); */
1291 
1292 		/* FALLTHROUGH */
1293 	case CTL_ALIAS:
1294 	  sb->sb_cc = sprintf(sb->sb_wptr,
1295 			      "Error: No application configured.\r\n");
1296 	  sb->sb_wptr += sb->sb_cc;
1297 	  return(0);
1298 
1299 	do_exec:
1300 		DEBUG_MISC((dfd, " executing %s \n",ex_ptr->ex_exec));
1301 		return(fork_exec(so, ex_ptr->ex_exec, do_pty));
1302 
1303 	case CTL_CMD:
1304 	   for (tmpso = tcb.so_next; tmpso != &tcb; tmpso = tmpso->so_next) {
1305 	     if (tmpso->so_emu == EMU_CTL &&
1306 		 !(tmpso->so_tcpcb?
1307 		   (tmpso->so_tcpcb->t_state & (TCPS_TIME_WAIT|TCPS_LAST_ACK))
1308 		   :0)) {
1309 	       /* Ooops, control connection already active */
1310 	       sb->sb_cc = sprintf(sb->sb_wptr,"Sorry, already connected.\r\n");
1311 	       sb->sb_wptr += sb->sb_cc;
1312 	       return 0;
1313 	     }
1314 	   }
1315 	   so->so_emu = EMU_CTL;
1316 	   ctl_password_ok = 0;
1317 	   sb->sb_cc = sprintf(sb->sb_wptr, "Slirp command-line ready (type \"help\" for help).\r\nSlirp> ");
1318 	   sb->sb_wptr += sb->sb_cc;
1319 	   do_echo=-1;
1320 	   return(2);
1321 	}
1322 #else
1323         return 0;
1324 #endif
1325 }
1326