1/* SPDX-License-Identifier: BSD-3-Clause */
2/*
3 * Copyright (c) 1982, 1986, 1988, 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * @(#)tcp_subr.c 8.1 (Berkeley) 6/10/93
31 * tcp_subr.c,v 1.5 1994/10/08 22:39:58 phk Exp
32 */
33
34/*
35 * Changes and additions relating to SLiRP
36 * Copyright (c) 1995 Danny Gasparovski.
37 */
38
39#include "slirp.h"
40
41/* patchable/settable parameters for tcp */
42/* Don't do rfc1323 performance enhancements */
43#define TCP_DO_RFC1323 0
44
45/*
46 * Tcp initialization
47 */
48void tcp_init(Slirp *slirp)
49{
50 slirp->tcp_iss = 1; /* wrong */
51 slirp->tcb.so_next = slirp->tcb.so_prev = &slirp->tcb;
52 slirp->tcp_last_so = &slirp->tcb;
53}
54
55void tcp_cleanup(Slirp *slirp)
56{
57 while (slirp->tcb.so_next != &slirp->tcb) {
58 tcp_close(sototcpcb(slirp->tcb.so_next));
59 }
60}
61
62/*
63 * Create template to be used to send tcp packets on a connection.
64 * Call after host entry created, fills
65 * in a skeletal tcp/ip header, minimizing the amount of work
66 * necessary when the connection is used.
67 */
68void tcp_template(struct tcpcb *tp)
69{
70 struct socket *so = tp->t_socket;
71 register struct tcpiphdr *n = &tp->t_template;
72
73 n->ti_mbuf = NULL;
74 memset(&n->ti, 0, sizeof(n->ti));
75 n->ti_x0 = 0;
76 switch (so->so_ffamily) {
77 case AF_INET:
78 n->ti_pr = IPPROTO_TCP;
79 n->ti_len = htons(sizeof(struct tcphdr));
80 n->ti_src = so->so_faddr;
81 n->ti_dst = so->so_laddr;
82 n->ti_sport = so->so_fport;
83 n->ti_dport = so->so_lport;
84 break;
85
86 case AF_INET6:
87 n->ti_nh6 = IPPROTO_TCP;
88 n->ti_len = htons(sizeof(struct tcphdr));
89 n->ti_src6 = so->so_faddr6;
90 n->ti_dst6 = so->so_laddr6;
91 n->ti_sport = so->so_fport6;
92 n->ti_dport = so->so_lport6;
93 break;
94
95 default:
96 g_assert_not_reached();
97 }
98
99 n->ti_seq = 0;
100 n->ti_ack = 0;
101 n->ti_x2 = 0;
102 n->ti_off = 5;
103 n->ti_flags = 0;
104 n->ti_win = 0;
105 n->ti_sum = 0;
106 n->ti_urp = 0;
107}
108
109/*
110 * Send a single message to the TCP at address specified by
111 * the given TCP/IP header. If m == 0, then we make a copy
112 * of the tcpiphdr at ti and send directly to the addressed host.
113 * This is used to force keep alive messages out using the TCP
114 * template for a connection tp->t_template. If flags are given
115 * then we send a message back to the TCP which originated the
116 * segment ti, and discard the mbuf containing it and any other
117 * attached mbufs.
118 *
119 * In any case the ack and sequence number of the transmitted
120 * segment are as specified by the parameters.
121 */
122void tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
123 tcp_seq ack, tcp_seq seq, int flags, unsigned short af)
124{
125 register int tlen;
126 int win = 0;
127
128 DEBUG_CALL("tcp_respond");
129 DEBUG_ARG("tp = %p", tp);
130 DEBUG_ARG("ti = %p", ti);
131 DEBUG_ARG("m = %p", m);
132 DEBUG_ARG("ack = %u", ack);
133 DEBUG_ARG("seq = %u", seq);
134 DEBUG_ARG("flags = %x", flags);
135
136 if (tp)
137 win = sbspace(&tp->t_socket->so_rcv);
138 if (m == NULL) {
139 if (!tp || (m = m_get(tp->t_socket->slirp)) == NULL)
140 return;
141 tlen = 0;
142 m->m_data += IF_MAXLINKHDR;
143 *mtod(m, struct tcpiphdr *) = *ti;
144 ti = mtod(m, struct tcpiphdr *);
145 switch (af) {
146 case AF_INET:
147 ti->ti.ti_i4.ih_x1 = 0;
148 break;
149 case AF_INET6:
150 ti->ti.ti_i6.ih_x1 = 0;
151 break;
152 default:
153 g_assert_not_reached();
154 }
155 flags = TH_ACK;
156 } else {
157 /*
158 * ti points into m so the next line is just making
159 * the mbuf point to ti
160 */
161 m->m_data = (char *)ti;
162
163 m->m_len = sizeof(struct tcpiphdr);
164 tlen = 0;
165#define xchg(a, b, type) \
166 { \
167 type t; \
168 t = a; \
169 a = b; \
170 b = t; \
171 }
172 switch (af) {
173 case AF_INET:
174 xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, uint32_t);
175 xchg(ti->ti_dport, ti->ti_sport, uint16_t);
176 break;
177 case AF_INET6:
178 xchg(ti->ti_dst6, ti->ti_src6, struct in6_addr);
179 xchg(ti->ti_dport, ti->ti_sport, uint16_t);
180 break;
181 default:
182 g_assert_not_reached();
183 }
184#undef xchg
185 }
186 ti->ti_len = htons((uint16_t)(sizeof(struct tcphdr) + tlen));
187 tlen += sizeof(struct tcpiphdr);
188 m->m_len = tlen;
189
190 ti->ti_mbuf = NULL;
191 ti->ti_x0 = 0;
192 ti->ti_seq = htonl(seq);
193 ti->ti_ack = htonl(ack);
194 ti->ti_x2 = 0;
195 ti->ti_off = sizeof(struct tcphdr) >> 2;
196 ti->ti_flags = flags;
197 if (tp)
198 ti->ti_win = htons((uint16_t)(win >> tp->rcv_scale));
199 else
200 ti->ti_win = htons((uint16_t)win);
201 ti->ti_urp = 0;
202 ti->ti_sum = 0;
203 ti->ti_sum = cksum(m, tlen);
204
205 struct tcpiphdr tcpiph_save = *(mtod(m, struct tcpiphdr *));
206 struct ip *ip;
207 struct ip6 *ip6;
208
209 switch (af) {
210 case AF_INET:
211 m->m_data +=
212 sizeof(struct tcpiphdr) - sizeof(struct tcphdr) - sizeof(struct ip);
213 m->m_len -=
214 sizeof(struct tcpiphdr) - sizeof(struct tcphdr) - sizeof(struct ip);
215 ip = mtod(m, struct ip *);
216 ip->ip_len = m->m_len;
217 ip->ip_dst = tcpiph_save.ti_dst;
218 ip->ip_src = tcpiph_save.ti_src;
219 ip->ip_p = tcpiph_save.ti_pr;
220
221 if (flags & TH_RST) {
222 ip->ip_ttl = MAXTTL;
223 } else {
224 ip->ip_ttl = IPDEFTTL;
225 }
226
227 ip_output(NULL, m);
228 break;
229
230 case AF_INET6:
231 m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
232 sizeof(struct ip6);
233 m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
234 sizeof(struct ip6);
235 ip6 = mtod(m, struct ip6 *);
236 ip6->ip_pl = tcpiph_save.ti_len;
237 ip6->ip_dst = tcpiph_save.ti_dst6;
238 ip6->ip_src = tcpiph_save.ti_src6;
239 ip6->ip_nh = tcpiph_save.ti_nh6;
240
241 ip6_output(NULL, m, 0);
242 break;
243
244 default:
245 g_assert_not_reached();
246 }
247}
248
249/*
250 * Create a new TCP control block, making an
251 * empty reassembly queue and hooking it to the argument
252 * protocol control block.
253 */
254struct tcpcb *tcp_newtcpcb(struct socket *so)
255{
256 register struct tcpcb *tp;
257
258 tp = (struct tcpcb *)malloc(sizeof(*tp));
259 if (tp == NULL)
260 return ((struct tcpcb *)0);
261
262 memset((char *)tp, 0, sizeof(struct tcpcb));
263 tp->seg_next = tp->seg_prev = (struct tcpiphdr *)tp;
264 tp->t_maxseg = (so->so_ffamily == AF_INET) ? TCP_MSS : TCP6_MSS;
265
266 tp->t_flags = TCP_DO_RFC1323 ? (TF_REQ_SCALE | TF_REQ_TSTMP) : 0;
267 tp->t_socket = so;
268
269 /*
270 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
271 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
272 * reasonable initial retransmit time.
273 */
274 tp->t_srtt = TCPTV_SRTTBASE;
275 tp->t_rttvar = TCPTV_SRTTDFLT << 2;
276 tp->t_rttmin = TCPTV_MIN;
277
278 TCPT_RANGESET(tp->t_rxtcur,
279 ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
280 TCPTV_MIN, TCPTV_REXMTMAX);
281
282 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
283 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
284 tp->t_state = TCPS_CLOSED;
285
286 so->so_tcpcb = tp;
287
288 return (tp);
289}
290
291/*
292 * Drop a TCP connection, reporting
293 * the specified error. If connection is synchronized,
294 * then send a RST to peer.
295 */
296struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
297{
298 DEBUG_CALL("tcp_drop");
299 DEBUG_ARG("tp = %p", tp);
300 DEBUG_ARG("errno = %d", errno);
301
302 if (TCPS_HAVERCVDSYN(tp->t_state)) {
303 tp->t_state = TCPS_CLOSED;
304 (void)tcp_output(tp);
305 }
306 return (tcp_close(tp));
307}
308
309/*
310 * Close a TCP control block:
311 * discard all space held by the tcp
312 * discard internet protocol block
313 * wake up any sleepers
314 */
315struct tcpcb *tcp_close(struct tcpcb *tp)
316{
317 register struct tcpiphdr *t;
318 struct socket *so = tp->t_socket;
319 Slirp *slirp = so->slirp;
320 register struct mbuf *m;
321
322 DEBUG_CALL("tcp_close");
323 DEBUG_ARG("tp = %p", tp);
324
325 /* free the reassembly queue, if any */
326 t = tcpfrag_list_first(tp);
327 while (!tcpfrag_list_end(t, tp)) {
328 t = tcpiphdr_next(t);
329 m = tcpiphdr_prev(t)->ti_mbuf;
330 remque(tcpiphdr2qlink(tcpiphdr_prev(t)));
331 m_free(m);
332 }
333 free(tp);
334 so->so_tcpcb = NULL;
335 /* clobber input socket cache if we're closing the cached connection */
336 if (so == slirp->tcp_last_so)
337 slirp->tcp_last_so = &slirp->tcb;
338 so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque);
339 closesocket(so->s);
340 sbfree(&so->so_rcv);
341 sbfree(&so->so_snd);
342 sofree(so);
343 return ((struct tcpcb *)0);
344}
345
346/*
347 * TCP protocol interface to socket abstraction.
348 */
349
350/*
351 * User issued close, and wish to trail through shutdown states:
352 * if never received SYN, just forget it. If got a SYN from peer,
353 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
354 * If already got a FIN from peer, then almost done; go to LAST_ACK
355 * state. In all other cases, have already sent FIN to peer (e.g.
356 * after PRU_SHUTDOWN), and just have to play tedious game waiting
357 * for peer to send FIN or not respond to keep-alives, etc.
358 * We can let the user exit from the close as soon as the FIN is acked.
359 */
360void tcp_sockclosed(struct tcpcb *tp)
361{
362 DEBUG_CALL("tcp_sockclosed");
363 DEBUG_ARG("tp = %p", tp);
364
365 if (!tp) {
366 return;
367 }
368
369 switch (tp->t_state) {
370 case TCPS_CLOSED:
371 case TCPS_LISTEN:
372 case TCPS_SYN_SENT:
373 tp->t_state = TCPS_CLOSED;
374 tp = tcp_close(tp);
375 break;
376
377 case TCPS_SYN_RECEIVED:
378 case TCPS_ESTABLISHED:
379 tp->t_state = TCPS_FIN_WAIT_1;
380 break;
381
382 case TCPS_CLOSE_WAIT:
383 tp->t_state = TCPS_LAST_ACK;
384 break;
385 }
386 tcp_output(tp);
387}
388
389/*
390 * Connect to a host on the Internet
391 * Called by tcp_input
392 * Only do a connect, the tcp fields will be set in tcp_input
393 * return 0 if there's a result of the connect,
394 * else return -1 means we're still connecting
395 * The return value is almost always -1 since the socket is
396 * nonblocking. Connect returns after the SYN is sent, and does
397 * not wait for ACK+SYN.
398 */
399int tcp_fconnect(struct socket *so, unsigned short af)
400{
401 int ret = 0;
402
403 DEBUG_CALL("tcp_fconnect");
404 DEBUG_ARG("so = %p", so);
405
406 ret = so->s = slirp_socket(af, SOCK_STREAM, 0);
407 if (ret >= 0) {
408 int opt, s = so->s;
409 struct sockaddr_storage addr;
410
411 slirp_set_nonblock(s);
412 so->slirp->cb->register_poll_fd(so->s, so->slirp->opaque);
413 slirp_socket_set_fast_reuse(s);
414 opt = 1;
415 setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
416 opt = 1;
417 setsockopt(s, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
418
419 addr = so->fhost.ss;
420 DEBUG_CALL(" connect()ing");
421 sotranslate_out(so, &addr);
422
423 /* We don't care what port we get */
424 ret = connect(s, (struct sockaddr *)&addr, sockaddr_size(&addr));
425
426 /*
427 * If it's not in progress, it failed, so we just return 0,
428 * without clearing SS_NOFDREF
429 */
430 soisfconnecting(so);
431 }
432
433 return (ret);
434}
435
436/*
437 * Accept the socket and connect to the local-host
438 *
439 * We have a problem. The correct thing to do would be
440 * to first connect to the local-host, and only if the
441 * connection is accepted, then do an accept() here.
442 * But, a) we need to know who's trying to connect
443 * to the socket to be able to SYN the local-host, and
444 * b) we are already connected to the foreign host by
445 * the time it gets to accept(), so... We simply accept
446 * here and SYN the local-host.
447 */
448void tcp_connect(struct socket *inso)
449{
450 Slirp *slirp = inso->slirp;
451 struct socket *so;
452 struct sockaddr_storage addr;
453 socklen_t addrlen = sizeof(struct sockaddr_storage);
454 struct tcpcb *tp;
455 int s, opt;
456
457 DEBUG_CALL("tcp_connect");
458 DEBUG_ARG("inso = %p", inso);
459
460 /*
461 * If it's an SS_ACCEPTONCE socket, no need to socreate()
462 * another socket, just use the accept() socket.
463 */
464 if (inso->so_state & SS_FACCEPTONCE) {
465 /* FACCEPTONCE already have a tcpcb */
466 so = inso;
467 } else {
468 so = socreate(slirp);
469 if (tcp_attach(so) < 0) {
470 g_free(so); /* NOT sofree */
471 return;
472 }
473 so->lhost = inso->lhost;
474 so->so_ffamily = inso->so_ffamily;
475 }
476
477 tcp_mss(sototcpcb(so), 0);
478
479 s = accept(inso->s, (struct sockaddr *)&addr, &addrlen);
480 if (s < 0) {
481 tcp_close(sototcpcb(so)); /* This will sofree() as well */
482 return;
483 }
484 slirp_set_nonblock(s);
485 so->slirp->cb->register_poll_fd(so->s, so->slirp->opaque);
486 slirp_socket_set_fast_reuse(s);
487 opt = 1;
488 setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
489 slirp_socket_set_nodelay(s);
490
491 so->fhost.ss = addr;
492 sotranslate_accept(so);
493
494 /* Close the accept() socket, set right state */
495 if (inso->so_state & SS_FACCEPTONCE) {
496 /* If we only accept once, close the accept() socket */
497 so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque);
498 closesocket(so->s);
499
500 /* Don't select it yet, even though we have an FD */
501 /* if it's not FACCEPTONCE, it's already NOFDREF */
502 so->so_state = SS_NOFDREF;
503 }
504 so->s = s;
505 so->so_state |= SS_INCOMING;
506
507 so->so_iptos = tcp_tos(so);
508 tp = sototcpcb(so);
509
510 tcp_template(tp);
511
512 tp->t_state = TCPS_SYN_SENT;
513 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
514 tp->iss = slirp->tcp_iss;
515 slirp->tcp_iss += TCP_ISSINCR / 2;
516 tcp_sendseqinit(tp);
517 tcp_output(tp);
518}
519
520/*
521 * Attach a TCPCB to a socket.
522 */
523int tcp_attach(struct socket *so)
524{
525 if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
526 return -1;
527
528 insque(so, &so->slirp->tcb);
529
530 return 0;
531}
532
533/*
534 * Set the socket's type of service field
535 */
536static const struct tos_t tcptos[] = {
537 { 0, 20, IPTOS_THROUGHPUT, 0 }, /* ftp data */
538 { 21, 21, IPTOS_LOWDELAY, EMU_FTP }, /* ftp control */
539 { 0, 23, IPTOS_LOWDELAY, 0 }, /* telnet */
540 { 0, 80, IPTOS_THROUGHPUT, 0 }, /* WWW */
541 { 0, 513, IPTOS_LOWDELAY, EMU_RLOGIN | EMU_NOCONNECT }, /* rlogin */
542 { 0, 544, IPTOS_LOWDELAY, EMU_KSH }, /* kshell */
543 { 0, 543, IPTOS_LOWDELAY, 0 }, /* klogin */
544 { 0, 6667, IPTOS_THROUGHPUT, EMU_IRC }, /* IRC */
545 { 0, 6668, IPTOS_THROUGHPUT, EMU_IRC }, /* IRC undernet */
546 { 0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
547 { 0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
548 { 0, 0, 0, 0 }
549};
550
551static struct emu_t *tcpemu = NULL;
552
553/*
554 * Return TOS according to the above table
555 */
556uint8_t tcp_tos(struct socket *so)
557{
558 int i = 0;
559 struct emu_t *emup;
560
561 while (tcptos[i].tos) {
562 if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
563 (tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
564 so->so_emu = tcptos[i].emu;
565 return tcptos[i].tos;
566 }
567 i++;
568 }
569
570 /* Nope, lets see if there's a user-added one */
571 for (emup = tcpemu; emup; emup = emup->next) {
572 if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
573 (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
574 so->so_emu = emup->emu;
575 return emup->tos;
576 }
577 }
578
579 return 0;
580}
581
582/*
583 * Emulate programs that try and connect to us
584 * This includes ftp (the data connection is
585 * initiated by the server) and IRC (DCC CHAT and
586 * DCC SEND) for now
587 *
588 * NOTE: It's possible to crash SLiRP by sending it
589 * unstandard strings to emulate... if this is a problem,
590 * more checks are needed here
591 *
592 * XXX Assumes the whole command came in one packet
593 *
594 * XXX Some ftp clients will have their TOS set to
595 * LOWDELAY and so Nagel will kick in. Because of this,
596 * we'll get the first letter, followed by the rest, so
597 * we simply scan for ORT instead of PORT...
598 * DCC doesn't have this problem because there's other stuff
599 * in the packet before the DCC command.
600 *
601 * Return 1 if the mbuf m is still valid and should be
602 * sbappend()ed
603 *
604 * NOTE: if you return 0 you MUST m_free() the mbuf!
605 */
606int tcp_emu(struct socket *so, struct mbuf *m)
607{
608 Slirp *slirp = so->slirp;
609 unsigned n1, n2, n3, n4, n5, n6;
610 char buff[257];
611 uint32_t laddr;
612 unsigned lport;
613 char *bptr;
614
615 DEBUG_CALL("tcp_emu");
616 DEBUG_ARG("so = %p", so);
617 DEBUG_ARG("m = %p", m);
618
619 switch (so->so_emu) {
620 int x, i;
621
622 /* TODO: IPv6 */
623 case EMU_IDENT:
624 /*
625 * Identification protocol as per rfc-1413
626 */
627
628 {
629 struct socket *tmpso;
630 struct sockaddr_in addr;
631 socklen_t addrlen = sizeof(struct sockaddr_in);
632 char *eol = g_strstr_len(m->m_data, m->m_len, "\r\n");
633
634 if (!eol) {
635 return 1;
636 }
637
638 *eol = '\0';
639 if (sscanf(m->m_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
640 HTONS(n1);
641 HTONS(n2);
642 /* n2 is the one on our host */
643 for (tmpso = slirp->tcb.so_next; tmpso != &slirp->tcb;
644 tmpso = tmpso->so_next) {
645 if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
646 tmpso->so_lport == n2 &&
647 tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
648 tmpso->so_fport == n1) {
649 if (getsockname(tmpso->s, (struct sockaddr *)&addr,
650 &addrlen) == 0)
651 n2 = addr.sin_port;
652 break;
653 }
654 }
655 NTOHS(n1);
656 NTOHS(n2);
657 m_inc(m, snprintf(NULL, 0, "%d,%d\r\n", n1, n2) + 1);
658 m->m_len = snprintf(m->m_data, M_ROOM(m), "%d,%d\r\n", n1, n2);
659 assert(m->m_len < M_ROOM(m));
660 } else {
661 *eol = '\r';
662 }
663
664 return 1;
665 }
666
667 case EMU_FTP: /* ftp */
668 m_inc(m, m->m_len + 1);
669 *(m->m_data + m->m_len) = 0; /* NUL terminate for strstr */
670 if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
671 /*
672 * Need to emulate the PORT command
673 */
674 x = sscanf(bptr, "ORT %u,%u,%u,%u,%u,%u\r\n%256[^\177]", &n1, &n2,
675 &n3, &n4, &n5, &n6, buff);
676 if (x < 6)
677 return 1;
678
679 laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
680 lport = htons((n5 << 8) | (n6));
681
682 if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr, lport,
683 SS_FACCEPTONCE)) == NULL) {
684 return 1;
685 }
686 n6 = ntohs(so->so_fport);
687
688 n5 = (n6 >> 8) & 0xff;
689 n6 &= 0xff;
690
691 laddr = ntohl(so->so_faddr.s_addr);
692
693 n1 = ((laddr >> 24) & 0xff);
694 n2 = ((laddr >> 16) & 0xff);
695 n3 = ((laddr >> 8) & 0xff);
696 n4 = (laddr & 0xff);
697
698 m->m_len = bptr - m->m_data; /* Adjust length */
699 m->m_len += snprintf(bptr, m->m_size - m->m_len,
700 "ORT %d,%d,%d,%d,%d,%d\r\n%s", n1, n2, n3, n4,
701 n5, n6, x == 7 ? buff : "");
702 return 1;
703 } else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
704 /*
705 * Need to emulate the PASV response
706 */
707 x = sscanf(
708 bptr,
709 "27 Entering Passive Mode (%u,%u,%u,%u,%u,%u)\r\n%256[^\177]",
710 &n1, &n2, &n3, &n4, &n5, &n6, buff);
711 if (x < 6)
712 return 1;
713
714 laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
715 lport = htons((n5 << 8) | (n6));
716
717 if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr, lport,
718 SS_FACCEPTONCE)) == NULL) {
719 return 1;
720 }
721 n6 = ntohs(so->so_fport);
722
723 n5 = (n6 >> 8) & 0xff;
724 n6 &= 0xff;
725
726 laddr = ntohl(so->so_faddr.s_addr);
727
728 n1 = ((laddr >> 24) & 0xff);
729 n2 = ((laddr >> 16) & 0xff);
730 n3 = ((laddr >> 8) & 0xff);
731 n4 = (laddr & 0xff);
732
733 m->m_len = bptr - m->m_data; /* Adjust length */
734 m->m_len +=
735 snprintf(bptr, m->m_size - m->m_len,
736 "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
737 n1, n2, n3, n4, n5, n6, x == 7 ? buff : "");
738
739 return 1;
740 }
741
742 return 1;
743
744 case EMU_KSH:
745 /*
746 * The kshell (Kerberos rsh) and shell services both pass
747 * a local port port number to carry signals to the server
748 * and stderr to the client. It is passed at the beginning
749 * of the connection as a NUL-terminated decimal ASCII string.
750 */
751 so->so_emu = 0;
752 for (lport = 0, i = 0; i < m->m_len - 1; ++i) {
753 if (m->m_data[i] < '0' || m->m_data[i] > '9')
754 return 1; /* invalid number */
755 lport *= 10;
756 lport += m->m_data[i] - '0';
757 }
758 if (m->m_data[m->m_len - 1] == '\0' && lport != 0 &&
759 (so = tcp_listen(slirp, INADDR_ANY, 0, so->so_laddr.s_addr,
760 htons(lport), SS_FACCEPTONCE)) != NULL)
761 m->m_len =
762 snprintf(m->m_data, m->m_size, "%d", ntohs(so->so_fport)) + 1;
763 return 1;
764
765 case EMU_IRC:
766 /*
767 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
768 */
769 m_inc(m, m->m_len + 1);
770 *(m->m_data + m->m_len) = 0; /* NULL terminate the string for strstr */
771 if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
772 return 1;
773
774 /* The %256s is for the broken mIRC */
775 if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
776 if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
777 htons(lport), SS_FACCEPTONCE)) == NULL) {
778 return 1;
779 }
780 m->m_len = bptr - m->m_data; /* Adjust length */
781 m->m_len += snprintf(bptr, m->m_size, "DCC CHAT chat %lu %u%c\n",
782 (unsigned long)ntohl(so->so_faddr.s_addr),
783 ntohs(so->so_fport), 1);
784 } else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport,
785 &n1) == 4) {
786 if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
787 htons(lport), SS_FACCEPTONCE)) == NULL) {
788 return 1;
789 }
790 m->m_len = bptr - m->m_data; /* Adjust length */
791 m->m_len +=
792 snprintf(bptr, m->m_size, "DCC SEND %s %lu %u %u%c\n", buff,
793 (unsigned long)ntohl(so->so_faddr.s_addr),
794 ntohs(so->so_fport), n1, 1);
795 } else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport,
796 &n1) == 4) {
797 if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
798 htons(lport), SS_FACCEPTONCE)) == NULL) {
799 return 1;
800 }
801 m->m_len = bptr - m->m_data; /* Adjust length */
802 m->m_len +=
803 snprintf(bptr, m->m_size, "DCC MOVE %s %lu %u %u%c\n", buff,
804 (unsigned long)ntohl(so->so_faddr.s_addr),
805 ntohs(so->so_fport), n1, 1);
806 }
807 return 1;
808
809 case EMU_REALAUDIO:
810 /*
811 * RealAudio emulation - JP. We must try to parse the incoming
812 * data and try to find the two characters that contain the
813 * port number. Then we redirect an udp port and replace the
814 * number with the real port we got.
815 *
816 * The 1.0 beta versions of the player are not supported
817 * any more.
818 *
819 * A typical packet for player version 1.0 (release version):
820 *
821 * 0000:50 4E 41 00 05
822 * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 ........g.l.c..P
823 * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
824 * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
825 * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
826 *
827 * Now the port number 0x1BD7 is found at offset 0x04 of the
828 * Now the port number 0x1BD7 is found at offset 0x04 of the
829 * second packet. This time we received five bytes first and
830 * then the rest. You never know how many bytes you get.
831 *
832 * A typical packet for player version 2.0 (beta):
833 *
834 * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA.............
835 * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux.c..Win2.0.0
836 * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
837 * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
838 * 0040:65 2E 72 61 79 53 00 00 06 36 42 e.rayS...6B
839 *
840 * Port number 0x1BC1 is found at offset 0x0d.
841 *
842 * This is just a horrible switch statement. Variable ra tells
843 * us where we're going.
844 */
845
846 bptr = m->m_data;
847 while (bptr < m->m_data + m->m_len) {
848 uint16_t p;
849 static int ra = 0;
850 char ra_tbl[4];
851
852 ra_tbl[0] = 0x50;
853 ra_tbl[1] = 0x4e;
854 ra_tbl[2] = 0x41;
855 ra_tbl[3] = 0;
856
857 switch (ra) {
858 case 0:
859 case 2:
860 case 3:
861 if (*bptr++ != ra_tbl[ra]) {
862 ra = 0;
863 continue;
864 }
865 break;
866
867 case 1:
868 /*
869 * We may get 0x50 several times, ignore them
870 */
871 if (*bptr == 0x50) {
872 ra = 1;
873 bptr++;
874 continue;
875 } else if (*bptr++ != ra_tbl[ra]) {
876 ra = 0;
877 continue;
878 }
879 break;
880
881 case 4:
882 /*
883 * skip version number
884 */
885 bptr++;
886 break;
887
888 case 5:
889 /*
890 * The difference between versions 1.0 and
891 * 2.0 is here. For future versions of
892 * the player this may need to be modified.
893 */
894 if (*(bptr + 1) == 0x02)
895 bptr += 8;
896 else
897 bptr += 4;
898 break;
899
900 case 6:
901 /* This is the field containing the port
902 * number that RA-player is listening to.
903 */
904 lport = (((uint8_t *)bptr)[0] << 8) + ((uint8_t *)bptr)[1];
905 if (lport < 6970)
906 lport += 256; /* don't know why */
907 if (lport < 6970 || lport > 7170)
908 return 1; /* failed */
909
910 /* try to get udp port between 6970 - 7170 */
911 for (p = 6970; p < 7071; p++) {
912 if (udp_listen(slirp, INADDR_ANY, htons(p),
913 so->so_laddr.s_addr, htons(lport),
914 SS_FACCEPTONCE)) {
915 break;
916 }
917 }
918 if (p == 7071)
919 p = 0;
920 *(uint8_t *)bptr++ = (p >> 8) & 0xff;
921 *(uint8_t *)bptr = p & 0xff;
922 ra = 0;
923 return 1; /* port redirected, we're done */
924 break;
925
926 default:
927 ra = 0;
928 }
929 ra++;
930 }
931 return 1;
932
933 default:
934 /* Ooops, not emulated, won't call tcp_emu again */
935 so->so_emu = 0;
936 return 1;
937 }
938}
939
940/*
941 * Do misc. config of SLiRP while its running.
942 * Return 0 if this connections is to be closed, 1 otherwise,
943 * return 2 if this is a command-line connection
944 */
945int tcp_ctl(struct socket *so)
946{
947 Slirp *slirp = so->slirp;
948 struct sbuf *sb = &so->so_snd;
949 struct gfwd_list *ex_ptr;
950
951 DEBUG_CALL("tcp_ctl");
952 DEBUG_ARG("so = %p", so);
953
954 /* TODO: IPv6 */
955 if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
956 /* Check if it's pty_exec */
957 for (ex_ptr = slirp->guestfwd_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
958 if (ex_ptr->ex_fport == so->so_fport &&
959 so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
960 if (ex_ptr->write_cb) {
961 so->s = -1;
962 so->guestfwd = ex_ptr;
963 return 1;
964 }
965 DEBUG_MISC(" executing %s", ex_ptr->ex_exec);
966 return fork_exec(so, ex_ptr->ex_exec);
967 }
968 }
969 }
970 sb->sb_cc =
971 snprintf(sb->sb_wptr, sb->sb_datalen - (sb->sb_wptr - sb->sb_data),
972 "Error: No application configured.\r\n");
973 sb->sb_wptr += sb->sb_cc;
974 return 0;
975}
976