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 #include "proxy_common.h"
48
49 /* patchable/settable parameters for tcp */
50 int tcp_mssdflt = TCP_MSS;
51 int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
52 int tcp_do_rfc1323 = 0; /* Don't do rfc1323 performance enhancements */
53 int tcp_rcvspace; /* You may want to change this */
54 int tcp_sndspace; /* Keep small if you have an error prone link */
55
56 /*
57 * Tcp initialization
58 */
59 void
tcp_init()60 tcp_init()
61 {
62 tcp_iss = 1; /* wrong */
63 tcb.so_next = tcb.so_prev = &tcb;
64
65 /* tcp_rcvspace = our Window we advertise to the remote */
66 tcp_rcvspace = TCP_RCVSPACE;
67 tcp_sndspace = TCP_SNDSPACE;
68
69 /* Make sure tcp_sndspace is at least 2*MSS */
70 if (tcp_sndspace < 2*(min(if_mtu, if_mru) - sizeof(struct tcpiphdr)))
71 tcp_sndspace = 2*(min(if_mtu, if_mru) - sizeof(struct tcpiphdr));
72 }
73
74 /*
75 * Create template to be used to send tcp packets on a connection.
76 * Call after host entry created, fills
77 * in a skeletal tcp/ip header, minimizing the amount of work
78 * necessary when the connection is used.
79 */
80 /* struct tcpiphdr * */
81 void
tcp_template(tp)82 tcp_template(tp)
83 struct tcpcb *tp;
84 {
85 struct socket *so = tp->t_socket;
86 register struct tcpiphdr *n = &tp->t_template;
87
88 n->ti_mbuf = NULL;
89 n->ti_x1 = 0;
90 n->ti_pr = IPPROTO_TCP;
91 n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
92 n->ti_src = ip_seth(so->so_faddr_ip);
93 n->ti_dst = ip_seth(so->so_laddr_ip);
94 n->ti_sport = port_seth(so->so_faddr_port);
95 n->ti_dport = port_seth(so->so_laddr_port);
96
97 n->ti_seq = 0;
98 n->ti_ack = 0;
99 n->ti_x2 = 0;
100 n->ti_off = 5;
101 n->ti_flags = 0;
102 n->ti_win = 0;
103 n->ti_sum = 0;
104 n->ti_urp = 0;
105 }
106
107 /*
108 * Send a single message to the TCP at address specified by
109 * the given TCP/IP header. If m == 0, then we make a copy
110 * of the tcpiphdr at ti and send directly to the addressed host.
111 * This is used to force keep alive messages out using the TCP
112 * template for a connection tp->t_template. If flags are given
113 * then we send a message back to the TCP which originated the
114 * segment ti, and discard the mbuf containing it and any other
115 * attached mbufs.
116 *
117 * In any case the ack and sequence number of the transmitted
118 * segment are as specified by the parameters.
119 */
120 void
tcp_respond(tp,ti,m,ack,seq,flags)121 tcp_respond(tp, ti, m, ack, seq, flags)
122 struct tcpcb *tp;
123 register struct tcpiphdr *ti;
124 register MBuf m;
125 tcp_seq ack, seq;
126 int flags;
127 {
128 register int tlen;
129 int win = 0;
130
131 DEBUG_CALL("tcp_respond");
132 DEBUG_ARG("tp = %lx", (long)tp);
133 DEBUG_ARG("ti = %lx", (long)ti);
134 DEBUG_ARG("m = %lx", (long)m);
135 DEBUG_ARG("ack = %u", ack);
136 DEBUG_ARG("seq = %u", seq);
137 DEBUG_ARG("flags = %x", flags);
138
139 if (tp)
140 win = sbuf_space(&tp->t_socket->so_rcv);
141 if (m == 0) {
142 if ((m = mbuf_alloc()) == NULL)
143 return;
144 #ifdef TCP_COMPAT_42
145 tlen = 1;
146 #else
147 tlen = 0;
148 #endif
149 m->m_data += if_maxlinkhdr;
150 *MBUF_TO(m, struct tcpiphdr *) = *ti;
151 ti = MBUF_TO(m, struct tcpiphdr *);
152 flags = TH_ACK;
153 } else {
154 /*
155 * ti points into m so the next line is just making
156 * the mbuf point to ti
157 */
158 m->m_data = (caddr_t)ti;
159
160 m->m_len = sizeof (struct tcpiphdr);
161 tlen = 0;
162 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
163 xchg(ti->ti_dst, ti->ti_src, ipaddr_t);
164 xchg(ti->ti_dport, ti->ti_sport, port_t);
165 #undef xchg
166 }
167 ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
168 tlen += sizeof (struct tcpiphdr);
169 m->m_len = tlen;
170
171 ti->ti_mbuf = 0;
172 ti->ti_x1 = 0;
173 ti->ti_seq = htonl(seq);
174 ti->ti_ack = htonl(ack);
175 ti->ti_x2 = 0;
176 ti->ti_off = sizeof (struct tcphdr) >> 2;
177 ti->ti_flags = flags;
178 if (tp)
179 ti->ti_win = htons((u_int16_t) (win >> tp->rcv_scale));
180 else
181 ti->ti_win = htons((u_int16_t)win);
182 ti->ti_urp = 0;
183 ti->ti_sum = 0;
184 ti->ti_sum = cksum(m, tlen);
185 ((struct ip *)ti)->ip_len = tlen;
186
187 if(flags & TH_RST)
188 ((struct ip *)ti)->ip_ttl = MAXTTL;
189 else
190 ((struct ip *)ti)->ip_ttl = ip_defttl;
191
192 (void) ip_output((struct socket *)0, m);
193 }
194
195 /*
196 * Create a new TCP control block, making an
197 * empty reassembly queue and hooking it to the argument
198 * protocol control block.
199 */
200 struct tcpcb *
tcp_newtcpcb(so)201 tcp_newtcpcb(so)
202 struct socket *so;
203 {
204 register struct tcpcb *tp;
205
206 tp = (struct tcpcb *)malloc(sizeof(*tp));
207 if (tp == NULL)
208 return ((struct tcpcb *)0);
209
210 memset((char *) tp, 0, sizeof(struct tcpcb));
211 tp->seg_next = tp->seg_prev = (struct tcpiphdr*)tp;
212 tp->t_maxseg = tcp_mssdflt;
213
214 tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0;
215 tp->t_socket = so;
216
217 /*
218 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
219 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
220 * reasonable initial retransmit time.
221 */
222 tp->t_srtt = TCPTV_SRTTBASE;
223 tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << 2;
224 tp->t_rttmin = TCPTV_MIN;
225
226 TCPT_RANGESET(tp->t_rxtcur,
227 ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
228 TCPTV_MIN, TCPTV_REXMTMAX);
229
230 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
231 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
232 tp->t_state = TCPS_CLOSED;
233
234 so->so_tcpcb = tp;
235
236 return (tp);
237 }
238
239 /*
240 * Drop a TCP connection, reporting
241 * the specified error. If connection is synchronized,
242 * then send a RST to peer.
243 */
tcp_drop(struct tcpcb * tp,int err)244 struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
245 {
246 /* tcp_drop(tp, errno)
247 register struct tcpcb *tp;
248 int errno;
249 {
250 */
251
252 DEBUG_CALL("tcp_drop");
253 DEBUG_ARG("tp = %lx", (long)tp);
254 DEBUG_ARG("errno = %d", errno);
255
256 if (TCPS_HAVERCVDSYN(tp->t_state)) {
257 tp->t_state = TCPS_CLOSED;
258 (void) tcp_output(tp);
259 tcpstat.tcps_drops++;
260 } else
261 tcpstat.tcps_conndrops++;
262 /* if (errno == ETIMEDOUT && tp->t_softerror)
263 * errno = tp->t_softerror;
264 */
265 /* so->so_error = errno; */
266 return (tcp_close(tp));
267 }
268
269 /*
270 * Close a TCP control block:
271 * discard all space held by the tcp
272 * discard internet protocol block
273 * wake up any sleepers
274 */
275 struct tcpcb *
tcp_close(tp)276 tcp_close(tp)
277 register struct tcpcb *tp;
278 {
279 register struct tcpiphdr *t;
280 struct socket *so = tp->t_socket;
281 register MBuf m;
282
283 DEBUG_CALL("tcp_close");
284 DEBUG_ARG("tp = %lx", (long )tp);
285
286 /* free the reassembly queue, if any */
287 t = tcpfrag_list_first(tp);
288 while (!tcpfrag_list_end(t, tp)) {
289 t = tcpiphdr_next(t);
290 m = tcpiphdr_prev(t)->ti_mbuf;
291 remque(tcpiphdr2qlink(tcpiphdr_prev(t)));
292 mbuf_free(m);
293 }
294 /* It's static */
295 /* if (tp->t_template)
296 * (void) mbuf_free(MBUF_FROM(tp->t_template));
297 */
298 /* free(tp, M_PCB); */
299 free(tp);
300 so->so_tcpcb = 0;
301 soisfdisconnected(so);
302 /* clobber input socket cache if we're closing the cached connection */
303 if (so == tcp_last_so)
304 tcp_last_so = &tcb;
305 socket_close(so->s);
306 sbuf_free(&so->so_rcv);
307 sbuf_free(&so->so_snd);
308 sofree(so);
309 tcpstat.tcps_closed++;
310 return ((struct tcpcb *)0);
311 }
312
313 void
tcp_drain()314 tcp_drain()
315 {
316 /* XXX */
317 }
318
319 /*
320 * When a source quench is received, close congestion window
321 * to one segment. We will gradually open it again as we proceed.
322 */
323
324 #ifdef notdef
325
326 void
tcp_quench(i,errno)327 tcp_quench(i, errno)
328
329 int errno;
330 {
331 struct tcpcb *tp = intotcpcb(inp);
332
333 if (tp)
334 tp->snd_cwnd = tp->t_maxseg;
335 }
336
337 #endif /* notdef */
338
339 /*
340 * TCP protocol interface to socket abstraction.
341 */
342
343 /*
344 * User issued close, and wish to trail through shutdown states:
345 * if never received SYN, just forget it. If got a SYN from peer,
346 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
347 * If already got a FIN from peer, then almost done; go to LAST_ACK
348 * state. In all other cases, have already sent FIN to peer (e.g.
349 * after PRU_SHUTDOWN), and just have to play tedious game waiting
350 * for peer to send FIN or not respond to keep-alives, etc.
351 * We can let the user exit from the close as soon as the FIN is acked.
352 */
353 void
tcp_sockclosed(tp)354 tcp_sockclosed(tp)
355 struct tcpcb *tp;
356 {
357
358 DEBUG_CALL("tcp_sockclosed");
359 DEBUG_ARG("tp = %lx", (long)tp);
360
361 switch (tp->t_state) {
362
363 case TCPS_CLOSED:
364 case TCPS_LISTEN:
365 case TCPS_SYN_SENT:
366 tp->t_state = TCPS_CLOSED;
367 tp = tcp_close(tp);
368 break;
369
370 case TCPS_SYN_RECEIVED:
371 case TCPS_ESTABLISHED:
372 tp->t_state = TCPS_FIN_WAIT_1;
373 break;
374
375 case TCPS_CLOSE_WAIT:
376 tp->t_state = TCPS_LAST_ACK;
377 break;
378 }
379 /* soisfdisconnecting(tp->t_socket); */
380 if (tp && tp->t_state >= TCPS_FIN_WAIT_2)
381 soisfdisconnected(tp->t_socket);
382 if (tp)
383 tcp_output(tp);
384 }
385
386 static void
tcp_proxy_event(struct socket * so,int s,ProxyEvent event)387 tcp_proxy_event( struct socket* so,
388 int s,
389 ProxyEvent event )
390 {
391 so->so_state &= ~SS_PROXIFIED;
392
393 if (event == PROXY_EVENT_CONNECTED) {
394 so->s = s;
395 so->so_state &= ~(SS_ISFCONNECTING);
396 }
397 else {
398 so->so_state = SS_NOFDREF;
399 }
400
401 /* continue the connect */
402 tcp_input(NULL, sizeof(struct ip), so);
403 }
404
405 /*
406 * Connect to a host on the Internet
407 * Called by tcp_input
408 * Only do a connect, the tcp fields will be set in tcp_input
409 * return 0 if there's a result of the connect,
410 * else return -1 means we're still connecting
411 * The return value is almost always -1 since the socket is
412 * nonblocking. Connect returns after the SYN is sent, and does
413 * not wait for ACK+SYN.
414 */
tcp_fconnect(so)415 int tcp_fconnect(so)
416 struct socket *so;
417 {
418 int ret=0;
419 int try_proxy = 1;
420 SockAddress sockaddr;
421 uint32_t sock_ip;
422 uint16_t sock_port;
423
424 DEBUG_CALL("tcp_fconnect");
425 DEBUG_ARG("so = %lx", (long )so);
426
427 sock_ip = so->so_faddr_ip;
428 sock_port = so->so_faddr_port;
429
430 if ((sock_ip & 0xffffff00) == special_addr_ip) {
431 /* It's an alias */
432 int last_byte = sock_ip & 0xff;
433
434 if (CTL_IS_DNS(last_byte))
435 sock_ip = dns_addr[last_byte - CTL_DNS];
436 else
437 sock_ip = loopback_addr_ip;
438 try_proxy = 0;
439 }
440
441 sock_address_init_inet( &sockaddr, sock_ip, sock_port );
442
443 DEBUG_MISC((dfd, " connect()ing, addr=%s, proxy=%d\n",
444 sock_address_to_string(&sockaddr), try_proxy));
445
446 if (try_proxy) {
447 if (!proxy_manager_add(&sockaddr, SOCKET_STREAM, (ProxyEventFunc) tcp_proxy_event, so)) {
448 soisfconnecting(so);
449 so->s = -1;
450 so->so_state |= SS_PROXIFIED;
451 return 0;
452 }
453 }
454
455 if ((ret=so->s=socket_create_inet(SOCKET_STREAM)) >= 0)
456 {
457 int s = so->s;
458
459 socket_set_nonblock(s);
460 socket_set_xreuseaddr(s);
461 socket_set_oobinline(s);
462
463 /* We don't care what port we get */
464 socket_connect(s, &sockaddr);
465
466 /*
467 * If it's not in progress, it failed, so we just return 0,
468 * without clearing SS_NOFDREF
469 */
470 soisfconnecting(so);
471 }
472
473 return(ret);
474 }
475
476 /*
477 * Accept the socket and connect to the local-host
478 *
479 * We have a problem. The correct thing to do would be
480 * to first connect to the local-host, and only if the
481 * connection is accepted, then do an accept() here.
482 * But, a) we need to know who's trying to connect
483 * to the socket to be able to SYN the local-host, and
484 * b) we are already connected to the foreign host by
485 * the time it gets to accept(), so... We simply accept
486 * here and SYN the local-host.
487 */
488 void
tcp_connect(inso)489 tcp_connect(inso)
490 struct socket *inso;
491 {
492 struct socket *so;
493 SockAddress addr;
494 uint32_t addr_ip;
495 struct tcpcb *tp;
496 int s;
497
498 DEBUG_CALL("tcp_connect");
499 DEBUG_ARG("inso = %lx", (long)inso);
500
501 /*
502 * If it's an SS_ACCEPTONCE socket, no need to socreate()
503 * another socket, just use the accept() socket.
504 */
505 if (inso->so_state & SS_FACCEPTONCE) {
506 /* FACCEPTONCE already have a tcpcb */
507 so = inso;
508 } else {
509 if ((so = socreate()) == NULL) {
510 /* If it failed, get rid of the pending connection */
511 socket_close(socket_accept(inso->s, NULL));
512 return;
513 }
514 if (tcp_attach(so) < 0) {
515 free(so); /* NOT sofree */
516 return;
517 }
518 so->so_laddr_ip = inso->so_laddr_ip;
519 so->so_laddr_port = inso->so_laddr_port;
520 }
521
522 (void) tcp_mss(sototcpcb(so), 0);
523
524 if ((s = socket_accept(inso->s, &addr)) < 0) {
525 tcp_close(sototcpcb(so)); /* This will sofree() as well */
526 return;
527 }
528 socket_set_nonblock(s);
529 socket_set_xreuseaddr(s);
530 socket_set_oobinline(s);
531 socket_set_nodelay(s);
532
533 so->so_faddr_port = sock_address_get_port(&addr);
534
535 addr_ip = sock_address_get_ip(&addr);
536
537 so->so_faddr_ip = addr_ip;
538 /* Translate connections from localhost to the real hostname */
539 if (addr_ip == 0 || addr_ip == loopback_addr_ip)
540 so->so_faddr_ip = alias_addr_ip;
541
542 /* Close the accept() socket, set right state */
543 if (inso->so_state & SS_FACCEPTONCE) {
544 socket_close(so->s); /* If we only accept once, close the accept() socket */
545 so->so_state = SS_NOFDREF; /* Don't select it yet, even though we have an FD */
546 /* if it's not FACCEPTONCE, it's already NOFDREF */
547 }
548 so->s = s;
549
550 so->so_iptos = tcp_tos(so);
551 tp = sototcpcb(so);
552
553 tcp_template(tp);
554
555 /* Compute window scaling to request. */
556 /* while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
557 * (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
558 * tp->request_r_scale++;
559 */
560
561 /* soisconnecting(so); */ /* NOFDREF used instead */
562 tcpstat.tcps_connattempt++;
563
564 tp->t_state = TCPS_SYN_SENT;
565 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
566 tp->iss = tcp_iss;
567 tcp_iss += TCP_ISSINCR/2;
568 tcp_sendseqinit(tp);
569 tcp_output(tp);
570 }
571
572 /*
573 * Attach a TCPCB to a socket.
574 */
575 int
tcp_attach(so)576 tcp_attach(so)
577 struct socket *so;
578 {
579 if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
580 return -1;
581
582 insque(so, &tcb);
583
584 return 0;
585 }
586
587 /*
588 * Set the socket's type of service field
589 */
590 struct tos_t tcptos[] = {
591 {0, 20, IPTOS_THROUGHPUT, 0}, /* ftp data */
592 {21, 21, IPTOS_LOWDELAY, EMU_FTP}, /* ftp control */
593 {0, 23, IPTOS_LOWDELAY, 0}, /* telnet */
594 {0, 80, IPTOS_THROUGHPUT, 0}, /* WWW */
595 {0, 513, IPTOS_LOWDELAY, EMU_RLOGIN|EMU_NOCONNECT}, /* rlogin */
596 {0, 514, IPTOS_LOWDELAY, EMU_RSH|EMU_NOCONNECT}, /* shell */
597 {0, 544, IPTOS_LOWDELAY, EMU_KSH}, /* kshell */
598 {0, 543, IPTOS_LOWDELAY, 0}, /* klogin */
599 {0, 6667, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC */
600 {0, 6668, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC undernet */
601 {0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
602 {0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
603 {0, 0, 0, 0}
604 };
605
606
607 /*
608 * Return TOS according to the above table
609 */
610 u_int8_t
tcp_tos(so)611 tcp_tos(so)
612 struct socket *so;
613 {
614 int i = 0;
615
616 while(tcptos[i].tos) {
617 if ((tcptos[i].fport && so->so_faddr_port == tcptos[i].fport) ||
618 (tcptos[i].lport && so->so_laddr_port == tcptos[i].lport)) {
619 so->so_emu = tcptos[i].emu;
620 return tcptos[i].tos;
621 }
622 i++;
623 }
624
625 return 0;
626 }
627
628 int do_echo = -1;
629
630 /*
631 * Emulate programs that try and connect to us
632 * This includes ftp (the data connection is
633 * initiated by the server) and IRC (DCC CHAT and
634 * DCC SEND) for now
635 *
636 * NOTE: It's possible to crash SLiRP by sending it
637 * unstandard strings to emulate... if this is a problem,
638 * more checks are needed here
639 *
640 * XXX Assumes the whole command came in one packet
641 *
642 * XXX Some ftp clients will have their TOS set to
643 * LOWDELAY and so Nagel will kick in. Because of this,
644 * we'll get the first letter, followed by the rest, so
645 * we simply scan for ORT instead of PORT...
646 * DCC doesn't have this problem because there's other stuff
647 * in the packet before the DCC command.
648 *
649 * Return 1 if the mbuf m is still valid and should be
650 * sbuf_append()ed
651 *
652 * NOTE: if you return 0 you MUST mbuf_free() the mbuf!
653 */
654 int
tcp_emu(so,m)655 tcp_emu(so, m)
656 struct socket *so;
657 MBuf m;
658 {
659 u_int n1, n2, n3, n4, n5, n6;
660 char buff[256];
661 u_int32_t laddr;
662 u_int lport;
663 char *bptr;
664
665 DEBUG_CALL("tcp_emu");
666 DEBUG_ARG("so = %lx", (long)so);
667 DEBUG_ARG("m = %lx", (long)m);
668
669 switch(so->so_emu) {
670 int x, i;
671
672 case EMU_IDENT:
673 /*
674 * Identification protocol as per rfc-1413
675 */
676
677 {
678 struct socket *tmpso;
679 SockAddress addr;
680 SBuf so_rcv = &so->so_rcv;
681
682 memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
683 so_rcv->sb_wptr += m->m_len;
684 so_rcv->sb_rptr += m->m_len;
685 m->m_data[m->m_len] = 0; /* NULL terminate */
686 if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
687 if (sscanf(so_rcv->sb_data, "%d%*[ ,]%d", &n1, &n2) == 2) {
688 /* n2 is the one on our host */
689 for (tmpso = tcb.so_next; tmpso != &tcb; tmpso = tmpso->so_next) {
690 if (tmpso->so_laddr_ip == so->so_laddr_ip &&
691 tmpso->so_laddr_port == n2 &&
692 tmpso->so_faddr_ip == so->so_faddr_ip &&
693 tmpso->so_faddr_port == n1) {
694 if (socket_get_address(tmpso->s, &addr) == 0)
695 n2 = sock_address_get_port(&addr);
696 break;
697 }
698 }
699 }
700 so_rcv->sb_cc = sprintf(so_rcv->sb_data, "%d,%d\r\n", n1, n2);
701 so_rcv->sb_rptr = so_rcv->sb_data;
702 so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
703 }
704 mbuf_free(m);
705 return 0;
706 }
707
708 case EMU_FTP: /* ftp */
709 *(m->m_data+m->m_len) = 0; /* NULL terminate for strstr */
710 if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
711 /*
712 * Need to emulate the PORT command
713 */
714 x = sscanf(bptr, "ORT %d,%d,%d,%d,%d,%d\r\n%256[^\177]",
715 &n1, &n2, &n3, &n4, &n5, &n6, buff);
716 if (x < 6)
717 return 1;
718
719 laddr = (n1 << 24) | (n2 << 16) | (n3 << 8) | (n4);
720 lport = (n5 << 8) | (n6);
721
722 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
723 return 1;
724
725 n6 = so->so_faddr_port;
726
727 n5 = (n6 >> 8) & 0xff;
728 n6 &= 0xff;
729
730 laddr = so->so_faddr_ip;
731
732 n1 = ((laddr >> 24) & 0xff);
733 n2 = ((laddr >> 16) & 0xff);
734 n3 = ((laddr >> 8) & 0xff);
735 n4 = (laddr & 0xff);
736
737 m->m_len = bptr - m->m_data; /* Adjust length */
738 m->m_len += sprintf(bptr,"ORT %d,%d,%d,%d,%d,%d\r\n%s",
739 n1, n2, n3, n4, n5, n6, x==7?buff:"");
740 return 1;
741 } else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
742 /*
743 * Need to emulate the PASV response
744 */
745 x = sscanf(bptr, "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%256[^\177]",
746 &n1, &n2, &n3, &n4, &n5, &n6, buff);
747 if (x < 6)
748 return 1;
749
750 laddr = (n1 << 24) | (n2 << 16) | (n3 << 8) | (n4);
751 lport = (n5 << 8) | (n6);
752
753 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
754 return 1;
755
756 n6 = so->so_faddr_port;
757
758 n5 = (n6 >> 8) & 0xff;
759 n6 &= 0xff;
760
761 laddr = so->so_faddr_ip;
762
763 n1 = ((laddr >> 24) & 0xff);
764 n2 = ((laddr >> 16) & 0xff);
765 n3 = ((laddr >> 8) & 0xff);
766 n4 = (laddr & 0xff);
767
768 m->m_len = bptr - m->m_data; /* Adjust length */
769 m->m_len += sprintf(bptr,"27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
770 n1, n2, n3, n4, n5, n6, x==7?buff:"");
771
772 return 1;
773 }
774
775 return 1;
776
777 case EMU_KSH:
778 /*
779 * The kshell (Kerberos rsh) and shell services both pass
780 * a local port port number to carry signals to the server
781 * and stderr to the client. It is passed at the beginning
782 * of the connection as a NUL-terminated decimal ASCII string.
783 */
784 so->so_emu = 0;
785 for (lport = 0, i = 0; i < m->m_len-1; ++i) {
786 if (m->m_data[i] < '0' || m->m_data[i] > '9')
787 return 1; /* invalid number */
788 lport *= 10;
789 lport += m->m_data[i] - '0';
790 }
791 if (m->m_data[m->m_len-1] == '\0' && lport != 0 &&
792 (so = solisten(0, so->so_laddr_ip, lport, SS_FACCEPTONCE)) != NULL)
793 m->m_len = sprintf(m->m_data, "%d", so->so_faddr_port)+1;
794 return 1;
795
796 case EMU_IRC:
797 /*
798 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
799 */
800 *(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
801 if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
802 return 1;
803
804 /* The %256s is for the broken mIRC */
805 if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
806 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
807 return 1;
808
809 m->m_len = bptr - m->m_data; /* Adjust length */
810 m->m_len += sprintf(bptr, "DCC CHAT chat %lu %u%c\n",
811 (unsigned long) so->so_faddr_ip,
812 so->so_faddr_port, 1);
813 } else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
814 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
815 return 1;
816
817 m->m_len = bptr - m->m_data; /* Adjust length */
818 m->m_len += sprintf(bptr, "DCC SEND %s %lu %u %u%c\n",
819 buff, (unsigned long)so->so_faddr_ip,
820 so->so_faddr_port, n1, 1);
821 } else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
822 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
823 return 1;
824
825 m->m_len = bptr - m->m_data; /* Adjust length */
826 m->m_len += sprintf(bptr, "DCC MOVE %s %lu %u %u%c\n",
827 buff, (unsigned long)so->so_faddr_ip,
828 so->so_faddr_port, n1, 1);
829 }
830 return 1;
831
832 case EMU_REALAUDIO:
833 /*
834 * RealAudio emulation - JP. We must try to parse the incoming
835 * data and try to find the two characters that contain the
836 * port number. Then we redirect an udp port and replace the
837 * number with the real port we got.
838 *
839 * The 1.0 beta versions of the player are not supported
840 * any more.
841 *
842 * A typical packet for player version 1.0 (release version):
843 *
844 * 0000:50 4E 41 00 05
845 * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 .....�..g�l�c..P
846 * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
847 * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
848 * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
849 *
850 * Now the port number 0x1BD7 is found at offset 0x04 of the
851 * Now the port number 0x1BD7 is found at offset 0x04 of the
852 * second packet. This time we received five bytes first and
853 * then the rest. You never know how many bytes you get.
854 *
855 * A typical packet for player version 2.0 (beta):
856 *
857 * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA...........�.
858 * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux�c..Win2.0.0
859 * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
860 * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
861 * 0040:65 2E 72 61 79 53 00 00 06 36 42 e.rayS...6B
862 *
863 * Port number 0x1BC1 is found at offset 0x0d.
864 *
865 * This is just a horrible switch statement. Variable ra tells
866 * us where we're going.
867 */
868
869 bptr = m->m_data;
870 while (bptr < m->m_data + m->m_len) {
871 u_short p;
872 static int ra = 0;
873 char ra_tbl[4];
874
875 ra_tbl[0] = 0x50;
876 ra_tbl[1] = 0x4e;
877 ra_tbl[2] = 0x41;
878 ra_tbl[3] = 0;
879
880 switch (ra) {
881 case 0:
882 case 2:
883 case 3:
884 if (*bptr++ != ra_tbl[ra]) {
885 ra = 0;
886 continue;
887 }
888 break;
889
890 case 1:
891 /*
892 * We may get 0x50 several times, ignore them
893 */
894 if (*bptr == 0x50) {
895 ra = 1;
896 bptr++;
897 continue;
898 } else if (*bptr++ != ra_tbl[ra]) {
899 ra = 0;
900 continue;
901 }
902 break;
903
904 case 4:
905 /*
906 * skip version number
907 */
908 bptr++;
909 break;
910
911 case 5:
912 /*
913 * The difference between versions 1.0 and
914 * 2.0 is here. For future versions of
915 * the player this may need to be modified.
916 */
917 if (*(bptr + 1) == 0x02)
918 bptr += 8;
919 else
920 bptr += 4;
921 break;
922
923 case 6:
924 /* This is the field containing the port
925 * number that RA-player is listening to.
926 */
927 lport = (((u_char*)bptr)[0] << 8)
928 + ((u_char *)bptr)[1];
929 if (lport < 6970)
930 lport += 256; /* don't know why */
931 if (lport < 6970 || lport > 7170)
932 return 1; /* failed */
933
934 /* try to get udp port between 6970 - 7170 */
935 for (p = 6970; p < 7071; p++) {
936 if (udp_listen( p,
937 so->so_laddr_ip,
938 lport,
939 SS_FACCEPTONCE)) {
940 break;
941 }
942 }
943 if (p == 7071)
944 p = 0;
945 *(u_char *)bptr++ = (p >> 8) & 0xff;
946 *(u_char *)bptr++ = p & 0xff;
947 ra = 0;
948 return 1; /* port redirected, we're done */
949 break;
950
951 default:
952 ra = 0;
953 }
954 ra++;
955 }
956 return 1;
957
958 default:
959 /* Ooops, not emulated, won't call tcp_emu again */
960 so->so_emu = 0;
961 return 1;
962 }
963 }
964
965 /*
966 * Do misc. config of SLiRP while its running.
967 * Return 0 if this connections is to be closed, 1 otherwise,
968 * return 2 if this is a command-line connection
969 */
970 int
tcp_ctl(so)971 tcp_ctl(so)
972 struct socket *so;
973 {
974 SBuf sb = &so->so_snd;
975 int command;
976 #if 0
977 struct ex_list *ex_ptr;
978 int do_pty;
979 #endif
980 // struct socket *tmpso;
981
982 DEBUG_CALL("tcp_ctl");
983 DEBUG_ARG("so = %lx", (long )so);
984
985 #if 0
986 /*
987 * Check if they're authorised
988 */
989 if (ctl_addr_ip && (ctl_addr_ip == -1 || (so->so_laddr_ip != ctl_addr_ip))) {
990 sb->sb_cc = sprintf(sb->sb_wptr,"Error: Permission denied.\r\n");
991 sb->sb_wptr += sb->sb_cc;
992 return 0;
993 }
994 #endif
995 command = (so->so_faddr_ip & 0xff);
996
997 switch(command) {
998 default:
999 /*
1000 * Nothing bound..
1001 */
1002 /* tcp_fconnect(so); */
1003
1004 case CTL_ALIAS:
1005 sb->sb_cc = sprintf(sb->sb_wptr,
1006 "Error: No application configured.\r\n");
1007 sb->sb_wptr += sb->sb_cc;
1008 return(0);
1009 }
1010 }
1011