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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)tcp_subr.c 8.1 (Berkeley) 6/10/93
30 * tcp_subr.c,v 1.5 1994/10/08 22:39:58 phk Exp
31 */
32
33 /*
34 * Changes and additions relating to SLiRP
35 * Copyright (c) 1995 Danny Gasparovski.
36 *
37 * Please read the file COPYRIGHT for the
38 * terms and conditions of the copyright.
39 */
40
41 #define WANT_SYS_IOCTL_H
42 #include <slirp.h>
43 #include "proxy_common.h"
44
45 /* patchable/settable parameters for tcp */
46 /* Don't do rfc1323 performance enhancements */
47 #define TCP_DO_RFC1323 0
48
49 /*
50 * Tcp initialization
51 */
52 void
tcp_init(void)53 tcp_init(void)
54 {
55 tcp_iss = 1; /* wrong */
56 tcb.so_next = tcb.so_prev = &tcb;
57 }
58
59 /*
60 * Create template to be used to send tcp packets on a connection.
61 * Call after host entry created, fills
62 * in a skeletal tcp/ip header, minimizing the amount of work
63 * necessary when the connection is used.
64 */
65 /* struct tcpiphdr * */
66 void
tcp_template(struct tcpcb * tp)67 tcp_template(struct tcpcb *tp)
68 {
69 struct socket *so = tp->t_socket;
70 register struct tcpiphdr *n = &tp->t_template;
71
72 n->ti_mbuf = NULL;
73 n->ti_x1 = 0;
74 n->ti_pr = IPPROTO_TCP;
75 n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
76 n->ti_src = ip_seth(so->so_faddr_ip);
77 n->ti_dst = ip_seth(so->so_laddr_ip);
78 n->ti_sport = port_seth(so->so_faddr_port);
79 n->ti_dport = port_seth(so->so_laddr_port);
80
81 n->ti_seq = 0;
82 n->ti_ack = 0;
83 n->ti_x2 = 0;
84 n->ti_off = 5;
85 n->ti_flags = 0;
86 n->ti_win = 0;
87 n->ti_sum = 0;
88 n->ti_urp = 0;
89 }
90
91 /*
92 * Send a single message to the TCP at address specified by
93 * the given TCP/IP header. If m == 0, then we make a copy
94 * of the tcpiphdr at ti and send directly to the addressed host.
95 * This is used to force keep alive messages out using the TCP
96 * template for a connection tp->t_template. If flags are given
97 * then we send a message back to the TCP which originated the
98 * segment ti, and discard the mbuf containing it and any other
99 * attached mbufs.
100 *
101 * In any case the ack and sequence number of the transmitted
102 * segment are as specified by the parameters.
103 */
104 void
tcp_respond(struct tcpcb * tp,struct tcpiphdr * ti,struct mbuf * m,tcp_seq ack,tcp_seq seq,int flags)105 tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
106 tcp_seq ack, tcp_seq seq, int flags)
107 {
108 register int tlen;
109 int win = 0;
110
111 DEBUG_CALL("tcp_respond");
112 DEBUG_ARG("tp = %lx", (long)tp);
113 DEBUG_ARG("ti = %lx", (long)ti);
114 DEBUG_ARG("m = %lx", (long)m);
115 DEBUG_ARG("ack = %u", ack);
116 DEBUG_ARG("seq = %u", seq);
117 DEBUG_ARG("flags = %x", flags);
118
119 if (tp)
120 win = sbspace(&tp->t_socket->so_rcv);
121 if (m == NULL) {
122 if ((m = m_get()) == NULL)
123 return;
124 #ifdef TCP_COMPAT_42
125 tlen = 1;
126 #else
127 tlen = 0;
128 #endif
129 m->m_data += IF_MAXLINKHDR;
130 *mtod(m, struct tcpiphdr *) = *ti;
131 ti = mtod(m, struct tcpiphdr *);
132 flags = TH_ACK;
133 } else {
134 /*
135 * ti points into m so the next line is just making
136 * the mbuf point to ti
137 */
138 m->m_data = (caddr_t)ti;
139
140 m->m_len = sizeof (struct tcpiphdr);
141 tlen = 0;
142 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
143 xchg(ti->ti_dst, ti->ti_src, ipaddr_t);
144 xchg(ti->ti_dport, ti->ti_sport, port_t);
145 #undef xchg
146 }
147 ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
148 tlen += sizeof (struct tcpiphdr);
149 m->m_len = tlen;
150
151 ti->ti_mbuf = NULL;
152 ti->ti_x1 = 0;
153 ti->ti_seq = htonl(seq);
154 ti->ti_ack = htonl(ack);
155 ti->ti_x2 = 0;
156 ti->ti_off = sizeof (struct tcphdr) >> 2;
157 ti->ti_flags = flags;
158 if (tp)
159 ti->ti_win = htons((u_int16_t) (win >> tp->rcv_scale));
160 else
161 ti->ti_win = htons((u_int16_t)win);
162 ti->ti_urp = 0;
163 ti->ti_sum = 0;
164 ti->ti_sum = cksum(m, tlen);
165 ((struct ip *)ti)->ip_len = tlen;
166
167 if(flags & TH_RST)
168 ((struct ip *)ti)->ip_ttl = MAXTTL;
169 else
170 ((struct ip *)ti)->ip_ttl = IPDEFTTL;
171
172 (void) ip_output((struct socket *)0, m);
173 }
174
175 /*
176 * Create a new TCP control block, making an
177 * empty reassembly queue and hooking it to the argument
178 * protocol control block.
179 */
180 struct tcpcb *
tcp_newtcpcb(struct socket * so)181 tcp_newtcpcb(struct socket *so)
182 {
183 register struct tcpcb *tp;
184
185 tp = (struct tcpcb *)malloc(sizeof(*tp));
186 if (tp == NULL)
187 return ((struct tcpcb *)0);
188
189 memset((char *) tp, 0, sizeof(struct tcpcb));
190 tp->seg_next = tp->seg_prev = (struct tcpiphdr*)tp;
191 tp->t_maxseg = TCP_MSS;
192
193 tp->t_flags = TCP_DO_RFC1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0;
194 tp->t_socket = so;
195
196 /*
197 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
198 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
199 * reasonable initial retransmit time.
200 */
201 tp->t_srtt = TCPTV_SRTTBASE;
202 tp->t_rttvar = TCPTV_SRTTDFLT << 2;
203 tp->t_rttmin = TCPTV_MIN;
204
205 TCPT_RANGESET(tp->t_rxtcur,
206 ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
207 TCPTV_MIN, TCPTV_REXMTMAX);
208
209 tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
210 tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
211 tp->t_state = TCPS_CLOSED;
212
213 so->so_tcpcb = tp;
214
215 return (tp);
216 }
217
218 /*
219 * Drop a TCP connection, reporting
220 * the specified error. If connection is synchronized,
221 * then send a RST to peer.
222 */
tcp_drop(struct tcpcb * tp,int err)223 struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
224 {
225 /* tcp_drop(tp, errno)
226 register struct tcpcb *tp;
227 int errno;
228 {
229 */
230
231 DEBUG_CALL("tcp_drop");
232 DEBUG_ARG("tp = %lx", (long)tp);
233 DEBUG_ARG("errno = %d", errno);
234
235 if (TCPS_HAVERCVDSYN(tp->t_state)) {
236 tp->t_state = TCPS_CLOSED;
237 (void) tcp_output(tp);
238 STAT(tcpstat.tcps_drops++);
239 } else
240 STAT(tcpstat.tcps_conndrops++);
241 /* if (errno == ETIMEDOUT && tp->t_softerror)
242 * errno = tp->t_softerror;
243 */
244 /* so->so_error = errno; */
245 return (tcp_close(tp));
246 }
247
248 /*
249 * Close a TCP control block:
250 * discard all space held by the tcp
251 * discard internet protocol block
252 * wake up any sleepers
253 */
254 struct tcpcb *
tcp_close(struct tcpcb * tp)255 tcp_close(struct tcpcb *tp)
256 {
257 register struct tcpiphdr *t;
258 struct socket *so = tp->t_socket;
259 register struct mbuf *m;
260
261 DEBUG_CALL("tcp_close");
262 DEBUG_ARG("tp = %lx", (long )tp);
263
264 /* free the reassembly queue, if any */
265 t = tcpfrag_list_first(tp);
266 while (!tcpfrag_list_end(t, tp)) {
267 t = tcpiphdr_next(t);
268 m = tcpiphdr_prev(t)->ti_mbuf;
269 remque(tcpiphdr2qlink(tcpiphdr_prev(t)));
270 m_freem(m);
271 }
272 /* It's static */
273 /* if (tp->t_template)
274 * (void) m_free(dtom(tp->t_template));
275 */
276 /* free(tp, M_PCB); */
277 free(tp);
278 so->so_tcpcb = NULL;
279 soisfdisconnected(so);
280 /* clobber input socket cache if we're closing the cached connection */
281 if (so == tcp_last_so)
282 tcp_last_so = &tcb;
283 socket_close(so->s);
284 sbfree(&so->so_rcv);
285 sbfree(&so->so_snd);
286 sofree(so);
287 STAT(tcpstat.tcps_closed++);
288 return ((struct tcpcb *)0);
289 }
290
291 #ifdef notdef
292 void
tcp_drain()293 tcp_drain()
294 {
295 /* XXX */
296 }
297
298 /*
299 * When a source quench is received, close congestion window
300 * to one segment. We will gradually open it again as we proceed.
301 */
302 void
tcp_quench(i,errno)303 tcp_quench(i, errno)
304
305 int errno;
306 {
307 struct tcpcb *tp = intotcpcb(inp);
308
309 if (tp)
310 tp->snd_cwnd = tp->t_maxseg;
311 }
312
313 #endif /* notdef */
314
315 /*
316 * TCP protocol interface to socket abstraction.
317 */
318
319 /*
320 * User issued close, and wish to trail through shutdown states:
321 * if never received SYN, just forget it. If got a SYN from peer,
322 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
323 * If already got a FIN from peer, then almost done; go to LAST_ACK
324 * state. In all other cases, have already sent FIN to peer (e.g.
325 * after PRU_SHUTDOWN), and just have to play tedious game waiting
326 * for peer to send FIN or not respond to keep-alives, etc.
327 * We can let the user exit from the close as soon as the FIN is acked.
328 */
329 void
tcp_sockclosed(struct tcpcb * tp)330 tcp_sockclosed(struct tcpcb *tp)
331 {
332
333 DEBUG_CALL("tcp_sockclosed");
334 DEBUG_ARG("tp = %lx", (long)tp);
335
336 switch (tp->t_state) {
337
338 case TCPS_CLOSED:
339 case TCPS_LISTEN:
340 case TCPS_SYN_SENT:
341 tp->t_state = TCPS_CLOSED;
342 tp = tcp_close(tp);
343 break;
344
345 case TCPS_SYN_RECEIVED:
346 case TCPS_ESTABLISHED:
347 tp->t_state = TCPS_FIN_WAIT_1;
348 break;
349
350 case TCPS_CLOSE_WAIT:
351 tp->t_state = TCPS_LAST_ACK;
352 break;
353 }
354 /* soisfdisconnecting(tp->t_socket); */
355 if (tp && tp->t_state >= TCPS_FIN_WAIT_2)
356 soisfdisconnected(tp->t_socket);
357 if (tp)
358 tcp_output(tp);
359 }
360
361 static void
tcp_proxy_event(struct socket * so,int s,ProxyEvent event)362 tcp_proxy_event( struct socket* so,
363 int s,
364 ProxyEvent event )
365 {
366 so->so_state &= ~SS_PROXIFIED;
367
368 if (event == PROXY_EVENT_CONNECTED) {
369 so->s = s;
370 so->so_state &= ~(SS_ISFCONNECTING);
371 }
372 else {
373 so->so_state = SS_NOFDREF;
374 }
375
376 /* continue the connect */
377 tcp_input(NULL, sizeof(struct ip), so);
378 }
379
380
381 /* Tests if an IP address corresponds to a special Qemu service (eg, the DNS
382 * server or the gateway - see ctl.h) and if so, rewrites it with the real
383 * address of the service.
384 */
is_qemu_special_address(unsigned long dst_addr,unsigned long * redir_addr)385 int is_qemu_special_address(unsigned long dst_addr, unsigned long *redir_addr)
386 {
387 if ((dst_addr & 0xffffff00) == special_addr_ip) {
388 /* It's an alias */
389
390 int last_byte = dst_addr & 0xff;
391
392 if (CTL_IS_DNS(last_byte))
393 *redir_addr = dns_addr[last_byte - CTL_DNS];
394 else
395 *redir_addr = loopback_addr_ip;
396
397 return 1;
398 }
399 return 0;
400 }
401
402
403 /*
404 * Connect to a host on the Internet
405 * Called by tcp_input
406 * Only do a connect, the tcp fields will be set in tcp_input
407 * return 0 if there's a result of the connect,
408 * else return -1 means we're still connecting
409 * The return value is almost always -1 since the socket is
410 * nonblocking. Connect returns after the SYN is sent, and does
411 * not wait for ACK+SYN.
412 */
tcp_fconnect(struct socket * so)413 int tcp_fconnect(struct socket *so)
414 {
415 int ret=0;
416 int try_proxy = 0;
417 SockAddress sockaddr;
418 unsigned long sock_ip;
419 int sock_port;
420 int redirect_happened = 0; /* for logging new src ip/port after connect */
421
422 DEBUG_CALL("tcp_fconnect");
423 DEBUG_ARG("so = %lx", (long )so);
424
425 /* when true, a connection that otherwise would be dropped will instead be
426 * redirected to the sink ('-net-forward-tcp2sink') */
427 int forward_dropped_to_sink = 0;
428 time_t timestamp = time(NULL);
429
430 /*-------------------------------------------------------------*/
431 /* User mode network stack restrictions */
432 if (slirp_should_drop(so->so_faddr_ip, so->so_faddr_port, IPPROTO_TCP)) {
433
434 /* If forwarding to sink is enabled, don't actually drop it */
435 if (slirp_should_forward_dropped_tcp2sink()) {
436 slirp_drop_log(
437 "About to be dropped TCP allowed to sink: "
438 "0x%08lx:0x%04x -> 0x%08lx:0x%04x %ld\n",
439 so->so_laddr_ip,
440 so->so_laddr_port,
441 so->so_faddr_ip,
442 so->so_faddr_port,
443 timestamp
444 );
445 forward_dropped_to_sink = 1;
446 }
447 else {
448 slirp_drop_log(
449 "Dropped TCP: 0x%08lx:0x%04x -> 0x%08lx:0x%04x %ld\n",
450 so->so_laddr_ip,
451 so->so_laddr_port,
452 so->so_faddr_ip,
453 so->so_faddr_port,
454 timestamp
455 );
456 //errno = ENETUNREACH;
457 errno = ECONNREFUSED;
458 return -1;
459 }
460 } else {
461 slirp_drop_log(
462 "Allowed TCP: 0x%08lx:0x%04x -> 0x%08lx:0x%04x %ld\n",
463 so->so_laddr_ip,
464 so->so_laddr_port,
465 so->so_faddr_ip,
466 so->so_faddr_port,
467 timestamp
468 );
469 }
470 /*-------------------------------------------------------------*/
471
472 if ((ret=so->s=socket_create_inet(SOCKET_STREAM)) >= 0)
473 {
474 int s = so->s;
475
476 socket_set_nonblock(s);
477 socket_set_xreuseaddr(s);
478 socket_set_oobinline(s);
479
480
481 if (forward_dropped_to_sink) {
482
483 /* This connection would normally be dropped, but since forwarding of
484 * dropped connections is enabled, redirect it to the sink */
485 sock_ip = slirp_get_tcp_sink_ip();
486 sock_port= slirp_get_tcp_sink_port();
487 redirect_happened = 1;
488 }
489 else { /* An allowed connection */
490
491 unsigned long faddr;
492 int fport;
493
494 /* Determine if the connection should be redirected
495 * due to a -net-forward rule */
496 /* faddr and fport are modified only on success */
497 if (slirp_should_net_forward(so->so_faddr_ip, so->so_faddr_port,
498 &faddr, &fport)) {
499 redirect_happened = 1;
500 sock_ip = faddr; /* forced dst addr */
501 sock_port= fport; /* forced dst port */
502 }
503 /* Determine if this is a connection to a special qemu service,
504 * and change the destination address accordingly.
505 * 'faddr' is modified only on success */
506 else if (is_qemu_special_address(so->so_faddr_ip, &faddr)) {
507
508 /* We keep the original destination port. If a special service
509 * listens on a different port than the standard, then appropriate
510 * forwarding should be set up using -net-forward, e.g., as it is
511 * the case with Mawler's DNS traffic, which is redirected to the
512 * special DNS port:
513 * -net-forward 0.0.0.0:0.0.0.0:53:127.0.0.1:21737 */
514
515 sock_ip = faddr; /* real DNS/gateway addr */
516 sock_port= so->so_faddr_port;/* original dst port */
517
518 }
519 /* A normal connection - keep the original destination addr/port */
520 else {
521
522 try_proxy = 1;
523
524 sock_ip = so->so_faddr_ip; /* original dst addr */
525 sock_port= so->so_faddr_port; /* original dst port */
526 }
527 }
528
529 DEBUG_MISC((dfd, " connect()ing, addr=%s, proxy=%d\n",
530 sock_address_to_string(&sockaddr), try_proxy));
531
532 sock_address_init_inet( &sockaddr, sock_ip, sock_port );
533
534 if (try_proxy) {
535 if (!proxy_manager_add(&sockaddr, SOCKET_STREAM,
536 (ProxyEventFunc) tcp_proxy_event, so)) {
537 soisfconnecting(so);
538 so->s = -1;
539 so->so_state |= SS_PROXIFIED;
540 return 0;
541 }
542 }
543
544 /* We don't care what port we get */
545 socket_connect(s, &sockaddr);
546
547 if (redirect_happened) {
548 SockAddress local_addr;
549 if (socket_get_address(s, &local_addr)) {
550 fprintf (stderr,
551 "Warning: tcp_fconnect: could not get socket name\n");
552 }
553 slirp_drop_log(
554 "Redirected TCP: orig 0x%08lx:0x%04x -> 0x%08lx:0x%04x "
555 "new 0x%08lx:0x%04x -> 0x%08lx:0x%04x %ld\n",
556 so->so_laddr_ip, so->so_laddr_port,
557 so->so_faddr_ip, so->so_laddr_port,
558 sock_address_get_ip(&local_addr),
559 sock_address_get_port(&local_addr),
560 sock_ip, sock_port, timestamp
561 );
562 }
563
564 /*
565 * If it's not in progress, it failed, so we just return 0,
566 * without clearing SS_NOFDREF
567 */
568 soisfconnecting(so);
569 }
570
571 return(ret);
572 }
573
574 /*
575 * Accept the socket and connect to the local-host
576 *
577 * We have a problem. The correct thing to do would be
578 * to first connect to the local-host, and only if the
579 * connection is accepted, then do an accept() here.
580 * But, a) we need to know who's trying to connect
581 * to the socket to be able to SYN the local-host, and
582 * b) we are already connected to the foreign host by
583 * the time it gets to accept(), so... We simply accept
584 * here and SYN the local-host.
585 */
586 void
tcp_connect(struct socket * inso)587 tcp_connect(struct socket *inso)
588 {
589 struct socket *so;
590 SockAddress addr;
591 uint32_t addr_ip;
592 struct tcpcb *tp;
593 int s;
594
595 DEBUG_CALL("tcp_connect");
596 DEBUG_ARG("inso = %lx", (long)inso);
597
598 /*
599 * If it's an SS_ACCEPTONCE socket, no need to socreate()
600 * another socket, just use the accept() socket.
601 */
602 if (inso->so_state & SS_FACCEPTONCE) {
603 /* FACCEPTONCE already have a tcpcb */
604 so = inso;
605 } else {
606 if ((so = socreate()) == NULL) {
607 /* If it failed, get rid of the pending connection */
608 socket_close(socket_accept(inso->s, NULL));
609 return;
610 }
611 if (tcp_attach(so) < 0) {
612 free(so); /* NOT sofree */
613 return;
614 }
615 so->so_laddr_ip = inso->so_laddr_ip;
616 so->so_laddr_port = inso->so_laddr_port;
617 }
618
619 (void) tcp_mss(sototcpcb(so), 0);
620
621 if ((s = socket_accept(inso->s, &addr)) < 0) {
622 tcp_close(sototcpcb(so)); /* This will sofree() as well */
623 return;
624 }
625 socket_set_nonblock(s);
626 socket_set_xreuseaddr(s);
627 socket_set_oobinline(s);
628 socket_set_nodelay(s);
629
630 so->so_faddr_port = sock_address_get_port(&addr);
631
632 addr_ip = sock_address_get_ip(&addr);
633
634 so->so_faddr_ip = addr_ip;
635 /* Translate connections from localhost to the real hostname */
636 if (addr_ip == 0 || addr_ip == loopback_addr_ip)
637 so->so_faddr_ip = alias_addr_ip;
638
639 /* Close the accept() socket, set right state */
640 if (inso->so_state & SS_FACCEPTONCE) {
641 socket_close(so->s); /* If we only accept once, close the accept() socket */
642 so->so_state = SS_NOFDREF; /* Don't select it yet, even though we have an FD */
643 /* if it's not FACCEPTONCE, it's already NOFDREF */
644 }
645 so->s = s;
646
647 so->so_iptos = tcp_tos(so);
648 tp = sototcpcb(so);
649
650 tcp_template(tp);
651
652 /* Compute window scaling to request. */
653 /* while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
654 * (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
655 * tp->request_r_scale++;
656 */
657
658 /* soisconnecting(so); */ /* NOFDREF used instead */
659 STAT(tcpstat.tcps_connattempt++);
660
661 tp->t_state = TCPS_SYN_SENT;
662 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
663 tp->iss = tcp_iss;
664 tcp_iss += TCP_ISSINCR/2;
665 tcp_sendseqinit(tp);
666 tcp_output(tp);
667 }
668
669 /*
670 * Attach a TCPCB to a socket.
671 */
672 int
tcp_attach(struct socket * so)673 tcp_attach(struct socket *so)
674 {
675 if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
676 return -1;
677
678 insque(so, &tcb);
679
680 return 0;
681 }
682
683 /*
684 * Set the socket's type of service field
685 */
686 static const struct tos_t tcptos[] = {
687 {0, 20, IPTOS_THROUGHPUT, 0}, /* ftp data */
688 {21, 21, IPTOS_LOWDELAY, EMU_FTP}, /* ftp control */
689 {0, 23, IPTOS_LOWDELAY, 0}, /* telnet */
690 {0, 80, IPTOS_THROUGHPUT, 0}, /* WWW */
691 {0, 513, IPTOS_LOWDELAY, EMU_RLOGIN|EMU_NOCONNECT}, /* rlogin */
692 {0, 514, IPTOS_LOWDELAY, EMU_RSH|EMU_NOCONNECT}, /* shell */
693 {0, 544, IPTOS_LOWDELAY, EMU_KSH}, /* kshell */
694 {0, 543, IPTOS_LOWDELAY, 0}, /* klogin */
695 {0, 6667, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC */
696 {0, 6668, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC undernet */
697 {0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
698 {0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
699 {0, 0, 0, 0}
700 };
701
702 #ifdef CONFIG_QEMU
703 static
704 #endif
705 struct emu_t *tcpemu = NULL;
706
707 /*
708 * Return TOS according to the above table
709 */
710 u_int8_t
tcp_tos(struct socket * so)711 tcp_tos(struct socket *so)
712 {
713 int i = 0;
714 struct emu_t *emup;
715
716 while(tcptos[i].tos) {
717 if ((tcptos[i].fport && so->so_faddr_port == tcptos[i].fport) ||
718 (tcptos[i].lport && so->so_laddr_port == tcptos[i].lport)) {
719 so->so_emu = tcptos[i].emu;
720 return tcptos[i].tos;
721 }
722 i++;
723 }
724
725 /* Nope, lets see if there's a user-added one */
726 for (emup = tcpemu; emup; emup = emup->next) {
727 if ((emup->fport && (so->so_faddr_port == emup->fport)) ||
728 (emup->lport && (so->so_laddr_port == emup->lport))) {
729 so->so_emu = emup->emu;
730 return emup->tos;
731 }
732 }
733 return 0;
734 }
735
736 #if 0
737 int do_echo = -1;
738 #endif
739
740 /*
741 * Emulate programs that try and connect to us
742 * This includes ftp (the data connection is
743 * initiated by the server) and IRC (DCC CHAT and
744 * DCC SEND) for now
745 *
746 * NOTE: It's possible to crash SLiRP by sending it
747 * unstandard strings to emulate... if this is a problem,
748 * more checks are needed here
749 *
750 * XXX Assumes the whole command came in one packet
751 *
752 * XXX Some ftp clients will have their TOS set to
753 * LOWDELAY and so Nagel will kick in. Because of this,
754 * we'll get the first letter, followed by the rest, so
755 * we simply scan for ORT instead of PORT...
756 * DCC doesn't have this problem because there's other stuff
757 * in the packet before the DCC command.
758 *
759 * Return 1 if the mbuf m is still valid and should be
760 * sbappend()ed
761 *
762 * NOTE: if you return 0 you MUST m_free() the mbuf!
763 */
764 int
tcp_emu(struct socket * so,struct mbuf * m)765 tcp_emu(struct socket *so, struct mbuf *m)
766 {
767 u_int n1, n2, n3, n4, n5, n6;
768 char buff[257];
769 u_int32_t laddr;
770 u_int lport;
771 char *bptr;
772
773 DEBUG_CALL("tcp_emu");
774 DEBUG_ARG("so = %lx", (long)so);
775 DEBUG_ARG("m = %lx", (long)m);
776
777 switch(so->so_emu) {
778 int x, i;
779
780 case EMU_IDENT:
781 /*
782 * Identification protocol as per rfc-1413
783 */
784
785 {
786 struct socket *tmpso;
787 SockAddress addr;
788 struct sbuf *so_rcv = &so->so_rcv;
789
790 memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
791 so_rcv->sb_wptr += m->m_len;
792 so_rcv->sb_rptr += m->m_len;
793 m->m_data[m->m_len] = 0; /* NULL terminate */
794 if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
795 if (sscanf(so_rcv->sb_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
796 /* n2 is the one on our host */
797 for (tmpso = tcb.so_next; tmpso != &tcb; tmpso = tmpso->so_next) {
798 if (tmpso->so_laddr_ip == so->so_laddr_ip &&
799 tmpso->so_laddr_port == n2 &&
800 tmpso->so_faddr_ip == so->so_faddr_ip &&
801 tmpso->so_faddr_port == n1) {
802 if (socket_get_address(tmpso->s, &addr) == 0)
803 n2 = sock_address_get_port(&addr);
804 break;
805 }
806 }
807 }
808 so_rcv->sb_cc = snprintf(so_rcv->sb_data,
809 so_rcv->sb_datalen,
810 "%d,%d\r\n", n1, n2);
811 so_rcv->sb_rptr = so_rcv->sb_data;
812 so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
813 }
814 m_free(m);
815 return 0;
816 }
817
818 case EMU_FTP: /* ftp */
819 *(m->m_data+m->m_len) = 0; /* NUL terminate for strstr */
820 if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
821 /*
822 * Need to emulate the PORT command
823 */
824 x = sscanf(bptr, "ORT %u,%u,%u,%u,%u,%u\r\n%256[^\177]",
825 &n1, &n2, &n3, &n4, &n5, &n6, buff);
826 if (x < 6)
827 return 1;
828
829 laddr = (n1 << 24) | (n2 << 16) | (n3 << 8) | (n4);
830 lport = (n5 << 8) | (n6);
831
832 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
833 return 1;
834
835 n6 = so->so_faddr_port;
836
837 n5 = (n6 >> 8) & 0xff;
838 n6 &= 0xff;
839
840 laddr = so->so_faddr_ip;
841
842 n1 = ((laddr >> 24) & 0xff);
843 n2 = ((laddr >> 16) & 0xff);
844 n3 = ((laddr >> 8) & 0xff);
845 n4 = (laddr & 0xff);
846
847 m->m_len = bptr - m->m_data; /* Adjust length */
848 m->m_len += snprintf(bptr, m->m_hdr.mh_size - m->m_len,
849 "ORT %d,%d,%d,%d,%d,%d\r\n%s",
850 n1, n2, n3, n4, n5, n6, x==7?buff:"");
851 return 1;
852 } else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
853 /*
854 * Need to emulate the PASV response
855 */
856 x = sscanf(bptr, "27 Entering Passive Mode (%u,%u,%u,%u,%u,%u)\r\n%256[^\177]",
857 &n1, &n2, &n3, &n4, &n5, &n6, buff);
858 if (x < 6)
859 return 1;
860
861 laddr = (n1 << 24) | (n2 << 16) | (n3 << 8) | (n4);
862 lport = (n5 << 8) | (n6);
863
864 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
865 return 1;
866
867 n6 = so->so_faddr_port;
868
869 n5 = (n6 >> 8) & 0xff;
870 n6 &= 0xff;
871
872 laddr = so->so_faddr_ip;
873
874 n1 = ((laddr >> 24) & 0xff);
875 n2 = ((laddr >> 16) & 0xff);
876 n3 = ((laddr >> 8) & 0xff);
877 n4 = (laddr & 0xff);
878
879 m->m_len = bptr - m->m_data; /* Adjust length */
880 m->m_len += snprintf(bptr, m->m_hdr.mh_size - m->m_len,
881 "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
882 n1, n2, n3, n4, n5, n6, x==7?buff:"");
883
884 return 1;
885 }
886
887 return 1;
888
889 case EMU_KSH:
890 /*
891 * The kshell (Kerberos rsh) and shell services both pass
892 * a local port port number to carry signals to the server
893 * and stderr to the client. It is passed at the beginning
894 * of the connection as a NUL-terminated decimal ASCII string.
895 */
896 so->so_emu = 0;
897 for (lport = 0, i = 0; i < m->m_len-1; ++i) {
898 if (m->m_data[i] < '0' || m->m_data[i] > '9')
899 return 1; /* invalid number */
900 lport *= 10;
901 lport += m->m_data[i] - '0';
902 }
903 if (m->m_data[m->m_len-1] == '\0' && lport != 0 &&
904 (so = solisten(0, so->so_laddr_ip, lport, SS_FACCEPTONCE)) != NULL)
905 m->m_len = snprintf(m->m_data, m->m_hdr.mh_size, "%d",
906 so->so_faddr_port) + 1;
907 return 1;
908
909 case EMU_IRC:
910 /*
911 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
912 */
913 *(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
914 if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
915 return 1;
916
917 /* The %256s is for the broken mIRC */
918 if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
919 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
920 return 1;
921
922 m->m_len = bptr - m->m_data; /* Adjust length */
923 m->m_len += snprintf(bptr, m->m_hdr.mh_size,
924 "DCC CHAT chat %lu %u%c\n",
925 (unsigned long) so->so_faddr_ip,
926 so->so_faddr_port, 1);
927 } else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
928 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
929 return 1;
930
931 m->m_len = bptr - m->m_data; /* Adjust length */
932 m->m_len += snprintf(bptr, m->m_hdr.mh_size,
933 "DCC SEND %s %u %u %u%c\n", buff,
934 so->so_faddr_ip, so->so_faddr_port, n1, 1);
935 } else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
936 if ((so = solisten(0, laddr, lport, SS_FACCEPTONCE)) == NULL)
937 return 1;
938
939 m->m_len = bptr - m->m_data; /* Adjust length */
940 m->m_len += snprintf(bptr, m->m_hdr.mh_size,
941 "DCC MOVE %s %lu %u %u%c\n", buff,
942 (unsigned long)so->so_faddr_ip,
943 so->so_faddr_port, n1, 1);
944 }
945 return 1;
946
947 case EMU_REALAUDIO:
948 /*
949 * RealAudio emulation - JP. We must try to parse the incoming
950 * data and try to find the two characters that contain the
951 * port number. Then we redirect an udp port and replace the
952 * number with the real port we got.
953 *
954 * The 1.0 beta versions of the player are not supported
955 * any more.
956 *
957 * A typical packet for player version 1.0 (release version):
958 *
959 * 0000:50 4E 41 00 05
960 * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 .....×..gælÜc..P
961 * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
962 * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
963 * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
964 *
965 * Now the port number 0x1BD7 is found at offset 0x04 of the
966 * Now the port number 0x1BD7 is found at offset 0x04 of the
967 * second packet. This time we received five bytes first and
968 * then the rest. You never know how many bytes you get.
969 *
970 * A typical packet for player version 2.0 (beta):
971 *
972 * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA...........Á.
973 * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .guxõc..Win2.0.0
974 * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
975 * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
976 * 0040:65 2E 72 61 79 53 00 00 06 36 42 e.rayS...6B
977 *
978 * Port number 0x1BC1 is found at offset 0x0d.
979 *
980 * This is just a horrible switch statement. Variable ra tells
981 * us where we're going.
982 */
983
984 bptr = m->m_data;
985 while (bptr < m->m_data + m->m_len) {
986 u_short p;
987 static int ra = 0;
988 char ra_tbl[4];
989
990 ra_tbl[0] = 0x50;
991 ra_tbl[1] = 0x4e;
992 ra_tbl[2] = 0x41;
993 ra_tbl[3] = 0;
994
995 switch (ra) {
996 case 0:
997 case 2:
998 case 3:
999 if (*bptr++ != ra_tbl[ra]) {
1000 ra = 0;
1001 continue;
1002 }
1003 break;
1004
1005 case 1:
1006 /*
1007 * We may get 0x50 several times, ignore them
1008 */
1009 if (*bptr == 0x50) {
1010 ra = 1;
1011 bptr++;
1012 continue;
1013 } else if (*bptr++ != ra_tbl[ra]) {
1014 ra = 0;
1015 continue;
1016 }
1017 break;
1018
1019 case 4:
1020 /*
1021 * skip version number
1022 */
1023 bptr++;
1024 break;
1025
1026 case 5:
1027 /*
1028 * The difference between versions 1.0 and
1029 * 2.0 is here. For future versions of
1030 * the player this may need to be modified.
1031 */
1032 if (*(bptr + 1) == 0x02)
1033 bptr += 8;
1034 else
1035 bptr += 4;
1036 break;
1037
1038 case 6:
1039 /* This is the field containing the port
1040 * number that RA-player is listening to.
1041 */
1042 lport = (((u_char*)bptr)[0] << 8)
1043 + ((u_char *)bptr)[1];
1044 if (lport < 6970)
1045 lport += 256; /* don't know why */
1046 if (lport < 6970 || lport > 7170)
1047 return 1; /* failed */
1048
1049 /* try to get udp port between 6970 - 7170 */
1050 for (p = 6970; p < 7071; p++) {
1051 if (udp_listen( p,
1052 so->so_laddr_ip,
1053 lport,
1054 SS_FACCEPTONCE)) {
1055 break;
1056 }
1057 }
1058 if (p == 7071)
1059 p = 0;
1060 *(u_char *)bptr++ = (p >> 8) & 0xff;
1061 *(u_char *)bptr++ = p & 0xff;
1062 ra = 0;
1063 return 1; /* port redirected, we're done */
1064 break;
1065
1066 default:
1067 ra = 0;
1068 }
1069 ra++;
1070 }
1071 return 1;
1072
1073 default:
1074 /* Ooops, not emulated, won't call tcp_emu again */
1075 so->so_emu = 0;
1076 return 1;
1077 }
1078 }
1079
1080 /*
1081 * Do misc. config of SLiRP while its running.
1082 * Return 0 if this connections is to be closed, 1 otherwise,
1083 * return 2 if this is a command-line connection
1084 */
1085 int
tcp_ctl(struct socket * so)1086 tcp_ctl(struct socket *so)
1087 {
1088 struct sbuf *sb = &so->so_snd;
1089 int command;
1090 struct ex_list *ex_ptr;
1091 int do_pty;
1092 // struct socket *tmpso;
1093
1094 DEBUG_CALL("tcp_ctl");
1095 DEBUG_ARG("so = %lx", (long )so);
1096
1097 #if 0
1098 /*
1099 * Check if they're authorised
1100 */
1101 if (ctl_addr_ip && (ctl_addr_ip == -1 || (so->so_laddr_ip != ctl_addr_ip))) {
1102 sb->sb_cc = sprintf(sb->sb_wptr,"Error: Permission denied.\r\n");
1103 sb->sb_wptr += sb->sb_cc;
1104 return 0;
1105 }
1106 #endif
1107 command = (so->so_faddr_ip & 0xff);
1108
1109 switch(command) {
1110 default: /* Check for exec's */
1111
1112 /*
1113 * Check if it's pty_exec
1114 */
1115 for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
1116 if (ex_ptr->ex_fport == so->so_faddr_port &&
1117 command == ex_ptr->ex_addr) {
1118 if (ex_ptr->ex_pty == 3) {
1119 so->s = -1;
1120 so->extra = (void *)ex_ptr->ex_exec;
1121 return 1;
1122 }
1123 do_pty = ex_ptr->ex_pty;
1124 goto do_exec;
1125 }
1126 }
1127
1128 /*
1129 * Nothing bound..
1130 */
1131 /* tcp_fconnect(so); */
1132
1133 /* FALLTHROUGH */
1134 case CTL_ALIAS:
1135 sb->sb_cc = snprintf(sb->sb_wptr, sb->sb_datalen - (sb->sb_wptr - sb->sb_data),
1136 "Error: No application configured.\r\n");
1137 sb->sb_wptr += sb->sb_cc;
1138 return(0);
1139
1140 do_exec:
1141 DEBUG_MISC((dfd, " executing %s \n",ex_ptr->ex_exec));
1142 return(fork_exec(so, ex_ptr->ex_exec, do_pty));
1143
1144 #if 0
1145 case CTL_CMD:
1146 for (tmpso = tcb.so_next; tmpso != &tcb; tmpso = tmpso->so_next) {
1147 if (tmpso->so_emu == EMU_CTL &&
1148 !(tmpso->so_tcpcb?
1149 (tmpso->so_tcpcb->t_state & (TCPS_TIME_WAIT|TCPS_LAST_ACK))
1150 :0)) {
1151 /* Ooops, control connection already active */
1152 sb->sb_cc = sprintf(sb->sb_wptr,"Sorry, already connected.\r\n");
1153 sb->sb_wptr += sb->sb_cc;
1154 return 0;
1155 }
1156 }
1157 so->so_emu = EMU_CTL;
1158 ctl_password_ok = 0;
1159 sb->sb_cc = sprintf(sb->sb_wptr, "Slirp command-line ready (type \"help\" for help).\r\nSlirp> ");
1160 sb->sb_wptr += sb->sb_cc;
1161 do_echo=-1;
1162 return(2);
1163 #endif
1164 }
1165 }
1166