Bug Summary

File:slirp/tcp_subr.c
Location:line 127, column 18
Description:Dereference of null pointer

Annotated Source Code

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#include <slirp.h>
42
43/* patchable/settable parameters for tcp */
44/* Don't do rfc1323 performance enhancements */
45#define TCP_DO_RFC13230 0
46
47/*
48 * Tcp initialization
49 */
50void
51tcp_init(Slirp *slirp)
52{
53 slirp->tcp_iss = 1; /* wrong */
54 slirp->tcb.so_next = slirp->tcb.so_prev = &slirp->tcb;
55 slirp->tcp_last_so = &slirp->tcb;
56}
57
58void tcp_cleanup(Slirp *slirp)
59{
60 while (slirp->tcb.so_next != &slirp->tcb) {
61 tcp_close(sototcpcb(slirp->tcb.so_next)((slirp->tcb.so_next)->so_tcpcb));
62 }
63}
64
65/*
66 * Create template to be used to send tcp packets on a connection.
67 * Call after host entry created, fills
68 * in a skeletal tcp/ip header, minimizing the amount of work
69 * necessary when the connection is used.
70 */
71void
72tcp_template(struct tcpcb *tp)
73{
74 struct socket *so = tp->t_socket;
75 register struct tcpiphdr *n = &tp->t_template;
76
77 n->ti_mbufti_i.ih_mbuf.mptr = NULL((void*)0);
78 n->ti_x1ti_i.ih_x1 = 0;
79 n->ti_prti_i.ih_pr = IPPROTO_TCPIPPROTO_TCP;
80 n->ti_lenti_i.ih_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
81 n->ti_srcti_i.ih_src = so->so_faddr;
82 n->ti_dstti_i.ih_dst = so->so_laddr;
83 n->ti_sportti_t.th_sport = so->so_fport;
84 n->ti_dportti_t.th_dport = so->so_lport;
85
86 n->ti_seqti_t.th_seq = 0;
87 n->ti_ackti_t.th_ack = 0;
88 n->ti_x2ti_t.th_x2 = 0;
89 n->ti_offti_t.th_off = 5;
90 n->ti_flagsti_t.th_flags = 0;
91 n->ti_winti_t.th_win = 0;
92 n->ti_sumti_t.th_sum = 0;
93 n->ti_urpti_t.th_urp = 0;
94}
95
96/*
97 * Send a single message to the TCP at address specified by
98 * the given TCP/IP header. If m == 0, then we make a copy
99 * of the tcpiphdr at ti and send directly to the addressed host.
100 * This is used to force keep alive messages out using the TCP
101 * template for a connection tp->t_template. If flags are given
102 * then we send a message back to the TCP which originated the
103 * segment ti, and discard the mbuf containing it and any other
104 * attached mbufs.
105 *
106 * In any case the ack and sequence number of the transmitted
107 * segment are as specified by the parameters.
108 */
109void
110tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
111 tcp_seq ack, tcp_seq seq, int flags)
112{
113 register int tlen;
114 int win = 0;
115
116 DEBUG_CALL("tcp_respond");
117 DEBUG_ARG("tp = %lx", (long)tp);
118 DEBUG_ARG("ti = %lx", (long)ti);
119 DEBUG_ARG("m = %lx", (long)m);
120 DEBUG_ARG("ack = %u", ack);
121 DEBUG_ARG("seq = %u", seq);
122 DEBUG_ARG("flags = %x", flags);
123
124 if (tp)
1
Assuming pointer value is null
2
Taking false branch
125 win = sbspace(&tp->t_socket->so_rcv)((&tp->t_socket->so_rcv)->sb_datalen - (&tp->
t_socket->so_rcv)->sb_cc);
126 if (m == NULL((void*)0)) {
3
Taking true branch
127 if ((m = m_get(tp->t_socket->slirp)) == NULL((void*)0))
4
Dereference of null pointer
128 return;
129 tlen = 0;
130 m->m_datam_hdr.mh_data += IF_MAXLINKHDR(2 + 14 + 40);
131 *mtod(m, struct tcpiphdr *)((struct tcpiphdr *)(m)->m_hdr.mh_data) = *ti;
132 ti = mtod(m, struct tcpiphdr *)((struct tcpiphdr *)(m)->m_hdr.mh_data);
133 flags = TH_ACK0x10;
134 } else {
135 /*
136 * ti points into m so the next line is just making
137 * the mbuf point to ti
138 */
139 m->m_datam_hdr.mh_data = (caddr_t)ti;
140
141 m->m_lenm_hdr.mh_len = sizeof (struct tcpiphdr);
142 tlen = 0;
143#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
144 xchg(ti->ti_dstti_i.ih_dst.s_addr, ti->ti_srcti_i.ih_src.s_addr, uint32_t);
145 xchg(ti->ti_dportti_t.th_dport, ti->ti_sportti_t.th_sport, uint16_t);
146#undef xchg
147 }
148 ti->ti_lenti_i.ih_len = htons((u_short)(sizeof (struct tcphdrslirp_tcphdr) + tlen));
149 tlen += sizeof (struct tcpiphdr);
150 m->m_lenm_hdr.mh_len = tlen;
151
152 ti->ti_mbufti_i.ih_mbuf.mptr = NULL((void*)0);
153 ti->ti_x1ti_i.ih_x1 = 0;
154 ti->ti_seqti_t.th_seq = htonl(seq);
155 ti->ti_ackti_t.th_ack = htonl(ack);
156 ti->ti_x2ti_t.th_x2 = 0;
157 ti->ti_offti_t.th_off = sizeof (struct tcphdrslirp_tcphdr) >> 2;
158 ti->ti_flagsti_t.th_flags = flags;
159 if (tp)
160 ti->ti_winti_t.th_win = htons((uint16_t) (win >> tp->rcv_scale));
161 else
162 ti->ti_winti_t.th_win = htons((uint16_t)win);
163 ti->ti_urpti_t.th_urp = 0;
164 ti->ti_sumti_t.th_sum = 0;
165 ti->ti_sumti_t.th_sum = cksum(m, tlen);
166 ((struct ip *)ti)->ip_len = tlen;
167
168 if(flags & TH_RST0x04)
169 ((struct ip *)ti)->ip_ttl = MAXTTL255;
170 else
171 ((struct ip *)ti)->ip_ttl = IPDEFTTL64;
172
173 (void) ip_output((struct socket *)0, m);
174}
175
176/*
177 * Create a new TCP control block, making an
178 * empty reassembly queue and hooking it to the argument
179 * protocol control block.
180 */
181struct tcpcb *
182tcp_newtcpcb(struct socket *so)
183{
184 register struct tcpcb *tp;
185
186 tp = (struct tcpcb *)malloc(sizeof(*tp));
187 if (tp == NULL((void*)0))
188 return ((struct tcpcb *)0);
189
190 memset((char *) tp, 0, sizeof(struct tcpcb));
191 tp->seg_next = tp->seg_prev = (struct tcpiphdr*)tp;
192 tp->t_maxseg = TCP_MSS1460;
193
194 tp->t_flags = TCP_DO_RFC13230 ? (TF_REQ_SCALE0x0020|TF_REQ_TSTMP0x0080) : 0;
195 tp->t_socket = so;
196
197 /*
198 * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
199 * rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
200 * reasonable initial retransmit time.
201 */
202 tp->t_srtt = TCPTV_SRTTBASE0;
203 tp->t_rttvar = TCPTV_SRTTDFLT( 3*2) << 2;
204 tp->t_rttmin = TCPTV_MIN( 1*2);
205
206 TCPT_RANGESET(tp->t_rxtcur,{ (tp->t_rxtcur) = (((0 >> 2) + (( 3*2) << 2))
>> 1); if ((tp->t_rxtcur) < (( 1*2))) (tp->t_rxtcur
) = (( 1*2)); else if ((tp->t_rxtcur) > (( 12*2))) (tp->
t_rxtcur) = (( 12*2)); }
207 ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,{ (tp->t_rxtcur) = (((0 >> 2) + (( 3*2) << 2))
>> 1); if ((tp->t_rxtcur) < (( 1*2))) (tp->t_rxtcur
) = (( 1*2)); else if ((tp->t_rxtcur) > (( 12*2))) (tp->
t_rxtcur) = (( 12*2)); }
208 TCPTV_MIN, TCPTV_REXMTMAX){ (tp->t_rxtcur) = (((0 >> 2) + (( 3*2) << 2))
>> 1); if ((tp->t_rxtcur) < (( 1*2))) (tp->t_rxtcur
) = (( 1*2)); else if ((tp->t_rxtcur) > (( 12*2))) (tp->
t_rxtcur) = (( 12*2)); };
209
210 tp->snd_cwnd = TCP_MAXWIN65535 << TCP_MAX_WINSHIFT14;
211 tp->snd_ssthresh = TCP_MAXWIN65535 << TCP_MAX_WINSHIFT14;
212 tp->t_state = TCPS_CLOSED0;
213
214 so->so_tcpcb = tp;
215
216 return (tp);
217}
218
219/*
220 * Drop a TCP connection, reporting
221 * the specified error. If connection is synchronized,
222 * then send a RST to peer.
223 */
224struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
225{
226 DEBUG_CALL("tcp_drop");
227 DEBUG_ARG("tp = %lx", (long)tp);
228 DEBUG_ARG("errno = %d", errno);
229
230 if (TCPS_HAVERCVDSYN(tp->t_state)((tp->t_state) >= 3)) {
231 tp->t_state = TCPS_CLOSED0;
232 (void) tcp_output(tp);
233 }
234 return (tcp_close(tp));
235}
236
237/*
238 * Close a TCP control block:
239 * discard all space held by the tcp
240 * discard internet protocol block
241 * wake up any sleepers
242 */
243struct tcpcb *
244tcp_close(struct tcpcb *tp)
245{
246 register struct tcpiphdr *t;
247 struct socket *so = tp->t_socket;
248 Slirp *slirp = so->slirp;
249 register struct mbuf *m;
250
251 DEBUG_CALL("tcp_close");
252 DEBUG_ARG("tp = %lx", (long )tp);
253
254 /* free the reassembly queue, if any */
255 t = tcpfrag_list_first(tp)((struct tcpiphdr*)(((char*)((tp)->seg_next)) + sizeof(struct
qlink)));
256 while (!tcpfrag_list_end(t, tp)(((struct qlink*)(((char*)(t)) - sizeof(struct qlink))) == (struct
qlink*)(tp))) {
257 t = tcpiphdr_next(t)((struct tcpiphdr*)(((char*)(((struct qlink*)(((char*)(t)) - sizeof
(struct qlink)))->next)) + sizeof(struct qlink)));
258 m = tcpiphdr_prev(t)((struct tcpiphdr*)(((char*)(((struct qlink*)(((char*)(t)) - sizeof
(struct qlink)))->prev)) + sizeof(struct qlink)))->ti_mbufti_i.ih_mbuf.mptr;
259 remqueslirp_remque(tcpiphdr2qlink(tcpiphdr_prev(t))((struct qlink*)(((char*)(((struct tcpiphdr*)(((char*)(((struct
qlink*)(((char*)(t)) - sizeof(struct qlink)))->prev)) + sizeof
(struct qlink))))) - sizeof(struct qlink))));
260 m_free(m);
261 }
262 free(tp);
263 so->so_tcpcb = NULL((void*)0);
264 /* clobber input socket cache if we're closing the cached connection */
265 if (so == slirp->tcp_last_so)
266 slirp->tcp_last_so = &slirp->tcb;
267 closesocket(so->s)close(so->s);
268 sbfree(&so->so_rcv);
269 sbfree(&so->so_snd);
270 sofree(so);
271 return ((struct tcpcb *)0);
272}
273
274/*
275 * TCP protocol interface to socket abstraction.
276 */
277
278/*
279 * User issued close, and wish to trail through shutdown states:
280 * if never received SYN, just forget it. If got a SYN from peer,
281 * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
282 * If already got a FIN from peer, then almost done; go to LAST_ACK
283 * state. In all other cases, have already sent FIN to peer (e.g.
284 * after PRU_SHUTDOWN), and just have to play tedious game waiting
285 * for peer to send FIN or not respond to keep-alives, etc.
286 * We can let the user exit from the close as soon as the FIN is acked.
287 */
288void
289tcp_sockclosed(struct tcpcb *tp)
290{
291
292 DEBUG_CALL("tcp_sockclosed");
293 DEBUG_ARG("tp = %lx", (long)tp);
294
295 switch (tp->t_state) {
296
297 case TCPS_CLOSED0:
298 case TCPS_LISTEN1:
299 case TCPS_SYN_SENT2:
300 tp->t_state = TCPS_CLOSED0;
301 tp = tcp_close(tp);
302 break;
303
304 case TCPS_SYN_RECEIVED3:
305 case TCPS_ESTABLISHED4:
306 tp->t_state = TCPS_FIN_WAIT_16;
307 break;
308
309 case TCPS_CLOSE_WAIT5:
310 tp->t_state = TCPS_LAST_ACK8;
311 break;
312 }
313 if (tp)
314 tcp_output(tp);
315}
316
317/*
318 * Connect to a host on the Internet
319 * Called by tcp_input
320 * Only do a connect, the tcp fields will be set in tcp_input
321 * return 0 if there's a result of the connect,
322 * else return -1 means we're still connecting
323 * The return value is almost always -1 since the socket is
324 * nonblocking. Connect returns after the SYN is sent, and does
325 * not wait for ACK+SYN.
326 */
327int tcp_fconnect(struct socket *so)
328{
329 Slirp *slirp = so->slirp;
330 int ret=0;
331
332 DEBUG_CALL("tcp_fconnect");
333 DEBUG_ARG("so = %lx", (long )so);
334
335 if( (ret = so->s = qemu_socket(AF_INET2,SOCK_STREAMSOCK_STREAM,0)) >= 0) {
336 int opt, s=so->s;
337 struct sockaddr_in addr;
338
339 socket_set_nonblock(s);
340 opt = 1;
341 setsockopt(s,SOL_SOCKET1,SO_REUSEADDR2,(char *)&opt,sizeof(opt ));
342 opt = 1;
343 setsockopt(s,SOL_SOCKET1,SO_OOBINLINE10,(char *)&opt,sizeof(opt ));
344
345 addr.sin_family = AF_INET2;
346 if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
347 slirp->vnetwork_addr.s_addr) {
348 /* It's an alias */
349 if (so->so_faddr.s_addr == slirp->vnameserver_addr.s_addr) {
350 if (get_dns_addr(&addr.sin_addr) < 0)
351 addr.sin_addr = loopback_addr;
352 } else {
353 addr.sin_addr = loopback_addr;
354 }
355 } else
356 addr.sin_addr = so->so_faddr;
357 addr.sin_port = so->so_fport;
358
359 DEBUG_MISC((dfd, " connect()ing, addr.sin_port=%d, "
360 "addr.sin_addr.s_addr=%.16s\n",
361 ntohs(addr.sin_port), inet_ntoa(addr.sin_addr)));
362 /* We don't care what port we get */
363 ret = connect(s,(struct sockaddr *)&addr,sizeof (addr));
364
365 /*
366 * If it's not in progress, it failed, so we just return 0,
367 * without clearing SS_NOFDREF
368 */
369 soisfconnecting(so);
370 }
371
372 return(ret);
373}
374
375/*
376 * Accept the socket and connect to the local-host
377 *
378 * We have a problem. The correct thing to do would be
379 * to first connect to the local-host, and only if the
380 * connection is accepted, then do an accept() here.
381 * But, a) we need to know who's trying to connect
382 * to the socket to be able to SYN the local-host, and
383 * b) we are already connected to the foreign host by
384 * the time it gets to accept(), so... We simply accept
385 * here and SYN the local-host.
386 */
387void
388tcp_connect(struct socket *inso)
389{
390 Slirp *slirp = inso->slirp;
391 struct socket *so;
392 struct sockaddr_in addr;
393 socklen_t addrlen = sizeof(struct sockaddr_in);
394 struct tcpcb *tp;
395 int s, opt;
396
397 DEBUG_CALL("tcp_connect");
398 DEBUG_ARG("inso = %lx", (long)inso);
399
400 /*
401 * If it's an SS_ACCEPTONCE socket, no need to socreate()
402 * another socket, just use the accept() socket.
403 */
404 if (inso->so_state & SS_FACCEPTONCE0x200) {
405 /* FACCEPTONCE already have a tcpcb */
406 so = inso;
407 } else {
408 if ((so = socreate(slirp)) == NULL((void*)0)) {
409 /* If it failed, get rid of the pending connection */
410 closesocket(accept(inso->s,(struct sockaddr *)&addr,&addrlen))close(accept(inso->s,(struct sockaddr *)&addr,&addrlen
));
411 return;
412 }
413 if (tcp_attach(so) < 0) {
414 free(so); /* NOT sofree */
415 return;
416 }
417 so->so_laddr = inso->so_laddr;
418 so->so_lport = inso->so_lport;
419 }
420
421 (void) tcp_mss(sototcpcb(so)((so)->so_tcpcb), 0);
422
423 if ((s = accept(inso->s,(struct sockaddr *)&addr,&addrlen)) < 0) {
424 tcp_close(sototcpcb(so)((so)->so_tcpcb)); /* This will sofree() as well */
425 return;
426 }
427 socket_set_nonblock(s);
428 opt = 1;
429 setsockopt(s,SOL_SOCKET1,SO_REUSEADDR2,(char *)&opt,sizeof(int));
430 opt = 1;
431 setsockopt(s,SOL_SOCKET1,SO_OOBINLINE10,(char *)&opt,sizeof(int));
432 opt = 1;
433 setsockopt(s,IPPROTO_TCPIPPROTO_TCP,TCP_NODELAY0x01,(char *)&opt,sizeof(int));
434
435 so->so_fport = addr.sin_port;
436 so->so_faddr = addr.sin_addr;
437 /* Translate connections from localhost to the real hostname */
438 if (so->so_faddr.s_addr == 0 || so->so_faddr.s_addr == loopback_addr.s_addr)
439 so->so_faddr = slirp->vhost_addr;
440
441 /* Close the accept() socket, set right state */
442 if (inso->so_state & SS_FACCEPTONCE0x200) {
443 closesocket(so->s)close(so->s); /* If we only accept once, close the accept() socket */
444 so->so_state = SS_NOFDREF0x001; /* Don't select it yet, even though we have an FD */
445 /* if it's not FACCEPTONCE, it's already NOFDREF */
446 }
447 so->s = s;
448 so->so_state |= SS_INCOMING0x2000;
449
450 so->so_iptos = tcp_tos(so);
451 tp = sototcpcb(so)((so)->so_tcpcb);
452
453 tcp_template(tp);
454
455 tp->t_state = TCPS_SYN_SENT2;
456 tp->t_timer[TCPT_KEEP2] = TCPTV_KEEP_INIT( 75*2);
457 tp->iss = slirp->tcp_iss;
458 slirp->tcp_iss += TCP_ISSINCR(125*1024)/2;
459 tcp_sendseqinit(tp)(tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)
->snd_up = (tp)->iss;
460 tcp_output(tp);
461}
462
463/*
464 * Attach a TCPCB to a socket.
465 */
466int
467tcp_attach(struct socket *so)
468{
469 if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL((void*)0))
470 return -1;
471
472 insqueslirp_insque(so, &so->slirp->tcb);
473
474 return 0;
475}
476
477/*
478 * Set the socket's type of service field
479 */
480static const struct tos_t tcptos[] = {
481 {0, 20, IPTOS_THROUGHPUT0x08, 0}, /* ftp data */
482 {21, 21, IPTOS_LOWDELAY0x10, EMU_FTP0x2}, /* ftp control */
483 {0, 23, IPTOS_LOWDELAY0x10, 0}, /* telnet */
484 {0, 80, IPTOS_THROUGHPUT0x08, 0}, /* WWW */
485 {0, 513, IPTOS_LOWDELAY0x10, EMU_RLOGIN0x6|EMU_NOCONNECT0x10}, /* rlogin */
486 {0, 514, IPTOS_LOWDELAY0x10, EMU_RSH0x8|EMU_NOCONNECT0x10}, /* shell */
487 {0, 544, IPTOS_LOWDELAY0x10, EMU_KSH0x3}, /* kshell */
488 {0, 543, IPTOS_LOWDELAY0x10, 0}, /* klogin */
489 {0, 6667, IPTOS_THROUGHPUT0x08, EMU_IRC0x4}, /* IRC */
490 {0, 6668, IPTOS_THROUGHPUT0x08, EMU_IRC0x4}, /* IRC undernet */
491 {0, 7070, IPTOS_LOWDELAY0x10, EMU_REALAUDIO0x5 }, /* RealAudio control */
492 {0, 113, IPTOS_LOWDELAY0x10, EMU_IDENT0x7 }, /* identd protocol */
493 {0, 0, 0, 0}
494};
495
496static struct emu_t *tcpemu = NULL((void*)0);
497
498/*
499 * Return TOS according to the above table
500 */
501uint8_t
502tcp_tos(struct socket *so)
503{
504 int i = 0;
505 struct emu_t *emup;
506
507 while(tcptos[i].tos) {
508 if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
509 (tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
510 so->so_emu = tcptos[i].emu;
511 return tcptos[i].tos;
512 }
513 i++;
514 }
515
516 /* Nope, lets see if there's a user-added one */
517 for (emup = tcpemu; emup; emup = emup->next) {
518 if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
519 (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
520 so->so_emu = emup->emu;
521 return emup->tos;
522 }
523 }
524
525 return 0;
526}
527
528/*
529 * Emulate programs that try and connect to us
530 * This includes ftp (the data connection is
531 * initiated by the server) and IRC (DCC CHAT and
532 * DCC SEND) for now
533 *
534 * NOTE: It's possible to crash SLiRP by sending it
535 * unstandard strings to emulate... if this is a problem,
536 * more checks are needed here
537 *
538 * XXX Assumes the whole command came in one packet
539 *
540 * XXX Some ftp clients will have their TOS set to
541 * LOWDELAY and so Nagel will kick in. Because of this,
542 * we'll get the first letter, followed by the rest, so
543 * we simply scan for ORT instead of PORT...
544 * DCC doesn't have this problem because there's other stuff
545 * in the packet before the DCC command.
546 *
547 * Return 1 if the mbuf m is still valid and should be
548 * sbappend()ed
549 *
550 * NOTE: if you return 0 you MUST m_free() the mbuf!
551 */
552int
553tcp_emu(struct socket *so, struct mbuf *m)
554{
555 Slirp *slirp = so->slirp;
556 u_int n1, n2, n3, n4, n5, n6;
557 char buff[257];
558 uint32_t laddr;
559 u_int lport;
560 char *bptr;
561
562 DEBUG_CALL("tcp_emu");
563 DEBUG_ARG("so = %lx", (long)so);
564 DEBUG_ARG("m = %lx", (long)m);
565
566 switch(so->so_emu) {
567 int x, i;
568
569 case EMU_IDENT0x7:
570 /*
571 * Identification protocol as per rfc-1413
572 */
573
574 {
575 struct socket *tmpso;
576 struct sockaddr_in addr;
577 socklen_t addrlen = sizeof(struct sockaddr_in);
578 struct sbuf *so_rcv = &so->so_rcv;
579
580 memcpy(so_rcv->sb_wptr, m->m_datam_hdr.mh_data, m->m_lenm_hdr.mh_len);
581 so_rcv->sb_wptr += m->m_lenm_hdr.mh_len;
582 so_rcv->sb_rptr += m->m_lenm_hdr.mh_len;
583 m->m_datam_hdr.mh_data[m->m_lenm_hdr.mh_len] = 0; /* NULL terminate */
584 if (strchr(m->m_datam_hdr.mh_data, '\r') || strchr(m->m_datam_hdr.mh_data, '\n')) {
585 if (sscanf(so_rcv->sb_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
586 HTONS(n1)((n1) = htons((uint16_t)(n1)));
587 HTONS(n2)((n2) = htons((uint16_t)(n2)));
588 /* n2 is the one on our host */
589 for (tmpso = slirp->tcb.so_next;
590 tmpso != &slirp->tcb;
591 tmpso = tmpso->so_next) {
592 if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
593 tmpso->so_lport == n2 &&
594 tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
595 tmpso->so_fport == n1) {
596 if (getsockname(tmpso->s,
597 (struct sockaddr *)&addr, &addrlen) == 0)
598 n2 = ntohs(addr.sin_port);
599 break;
600 }
601 }
602 }
603 so_rcv->sb_cc = snprintf(so_rcv->sb_data,
604 so_rcv->sb_datalen,
605 "%d,%d\r\n", n1, n2);
606 so_rcv->sb_rptr = so_rcv->sb_data;
607 so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
608 }
609 m_free(m);
610 return 0;
611 }
612
613 case EMU_FTP0x2: /* ftp */
614 *(m->m_datam_hdr.mh_data+m->m_lenm_hdr.mh_len) = 0; /* NUL terminate for strstr */
615 if ((bptr = (char *)strstr(m->m_datam_hdr.mh_data, "ORT")) != NULL((void*)0)) {
616 /*
617 * Need to emulate the PORT command
618 */
619 x = sscanf(bptr, "ORT %u,%u,%u,%u,%u,%u\r\n%256[^\177]",
620 &n1, &n2, &n3, &n4, &n5, &n6, buff);
621 if (x < 6)
622 return 1;
623
624 laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
625 lport = htons((n5 << 8) | (n6));
626
627 if ((so = tcp_listen(slirp, INADDR_ANY((in_addr_t) 0x00000000), 0, laddr,
628 lport, SS_FACCEPTONCE0x200)) == NULL((void*)0)) {
629 return 1;
630 }
631 n6 = ntohs(so->so_fport);
632
633 n5 = (n6 >> 8) & 0xff;
634 n6 &= 0xff;
635
636 laddr = ntohl(so->so_faddr.s_addr);
637
638 n1 = ((laddr >> 24) & 0xff);
639 n2 = ((laddr >> 16) & 0xff);
640 n3 = ((laddr >> 8) & 0xff);
641 n4 = (laddr & 0xff);
642
643 m->m_lenm_hdr.mh_len = bptr - m->m_datam_hdr.mh_data; /* Adjust length */
644 m->m_lenm_hdr.mh_len += snprintf(bptr, m->m_hdr.mh_size - m->m_lenm_hdr.mh_len,
645 "ORT %d,%d,%d,%d,%d,%d\r\n%s",
646 n1, n2, n3, n4, n5, n6, x==7?buff:"");
647 return 1;
648 } else if ((bptr = (char *)strstr(m->m_datam_hdr.mh_data, "27 Entering")) != NULL((void*)0)) {
649 /*
650 * Need to emulate the PASV response
651 */
652 x = sscanf(bptr, "27 Entering Passive Mode (%u,%u,%u,%u,%u,%u)\r\n%256[^\177]",
653 &n1, &n2, &n3, &n4, &n5, &n6, buff);
654 if (x < 6)
655 return 1;
656
657 laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
658 lport = htons((n5 << 8) | (n6));
659
660 if ((so = tcp_listen(slirp, INADDR_ANY((in_addr_t) 0x00000000), 0, laddr,
661 lport, SS_FACCEPTONCE0x200)) == NULL((void*)0)) {
662 return 1;
663 }
664 n6 = ntohs(so->so_fport);
665
666 n5 = (n6 >> 8) & 0xff;
667 n6 &= 0xff;
668
669 laddr = ntohl(so->so_faddr.s_addr);
670
671 n1 = ((laddr >> 24) & 0xff);
672 n2 = ((laddr >> 16) & 0xff);
673 n3 = ((laddr >> 8) & 0xff);
674 n4 = (laddr & 0xff);
675
676 m->m_lenm_hdr.mh_len = bptr - m->m_datam_hdr.mh_data; /* Adjust length */
677 m->m_lenm_hdr.mh_len += snprintf(bptr, m->m_hdr.mh_size - m->m_lenm_hdr.mh_len,
678 "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
679 n1, n2, n3, n4, n5, n6, x==7?buff:"");
680
681 return 1;
682 }
683
684 return 1;
685
686 case EMU_KSH0x3:
687 /*
688 * The kshell (Kerberos rsh) and shell services both pass
689 * a local port port number to carry signals to the server
690 * and stderr to the client. It is passed at the beginning
691 * of the connection as a NUL-terminated decimal ASCII string.
692 */
693 so->so_emu = 0;
694 for (lport = 0, i = 0; i < m->m_lenm_hdr.mh_len-1; ++i) {
695 if (m->m_datam_hdr.mh_data[i] < '0' || m->m_datam_hdr.mh_data[i] > '9')
696 return 1; /* invalid number */
697 lport *= 10;
698 lport += m->m_datam_hdr.mh_data[i] - '0';
699 }
700 if (m->m_datam_hdr.mh_data[m->m_lenm_hdr.mh_len-1] == '\0' && lport != 0 &&
701 (so = tcp_listen(slirp, INADDR_ANY((in_addr_t) 0x00000000), 0, so->so_laddr.s_addr,
702 htons(lport), SS_FACCEPTONCE0x200)) != NULL((void*)0))
703 m->m_lenm_hdr.mh_len = snprintf(m->m_datam_hdr.mh_data, m->m_hdr.mh_size, "%d",
704 ntohs(so->so_fport)) + 1;
705 return 1;
706
707 case EMU_IRC0x4:
708 /*
709 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
710 */
711 *(m->m_datam_hdr.mh_data+m->m_lenm_hdr.mh_len) = 0; /* NULL terminate the string for strstr */
712 if ((bptr = (char *)strstr(m->m_datam_hdr.mh_data, "DCC")) == NULL((void*)0))
713 return 1;
714
715 /* The %256s is for the broken mIRC */
716 if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
717 if ((so = tcp_listen(slirp, INADDR_ANY((in_addr_t) 0x00000000), 0,
718 htonl(laddr), htons(lport),
719 SS_FACCEPTONCE0x200)) == NULL((void*)0)) {
720 return 1;
721 }
722 m->m_lenm_hdr.mh_len = bptr - m->m_datam_hdr.mh_data; /* Adjust length */
723 m->m_lenm_hdr.mh_len += snprintf(bptr, m->m_hdr.mh_size,
724 "DCC CHAT chat %lu %u%c\n",
725 (unsigned long)ntohl(so->so_faddr.s_addr),
726 ntohs(so->so_fport), 1);
727 } else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
728 if ((so = tcp_listen(slirp, INADDR_ANY((in_addr_t) 0x00000000), 0,
729 htonl(laddr), htons(lport),
730 SS_FACCEPTONCE0x200)) == NULL((void*)0)) {
731 return 1;
732 }
733 m->m_lenm_hdr.mh_len = bptr - m->m_datam_hdr.mh_data; /* Adjust length */
734 m->m_lenm_hdr.mh_len += snprintf(bptr, m->m_hdr.mh_size,
735 "DCC SEND %s %lu %u %u%c\n", buff,
736 (unsigned long)ntohl(so->so_faddr.s_addr),
737 ntohs(so->so_fport), n1, 1);
738 } else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
739 if ((so = tcp_listen(slirp, INADDR_ANY((in_addr_t) 0x00000000), 0,
740 htonl(laddr), htons(lport),
741 SS_FACCEPTONCE0x200)) == NULL((void*)0)) {
742 return 1;
743 }
744 m->m_lenm_hdr.mh_len = bptr - m->m_datam_hdr.mh_data; /* Adjust length */
745 m->m_lenm_hdr.mh_len += snprintf(bptr, m->m_hdr.mh_size,
746 "DCC MOVE %s %lu %u %u%c\n", buff,
747 (unsigned long)ntohl(so->so_faddr.s_addr),
748 ntohs(so->so_fport), n1, 1);
749 }
750 return 1;
751
752 case EMU_REALAUDIO0x5:
753 /*
754 * RealAudio emulation - JP. We must try to parse the incoming
755 * data and try to find the two characters that contain the
756 * port number. Then we redirect an udp port and replace the
757 * number with the real port we got.
758 *
759 * The 1.0 beta versions of the player are not supported
760 * any more.
761 *
762 * A typical packet for player version 1.0 (release version):
763 *
764 * 0000:50 4E 41 00 05
765 * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 ........g.l.c..P
766 * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
767 * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
768 * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
769 *
770 * Now the port number 0x1BD7 is found at offset 0x04 of the
771 * Now the port number 0x1BD7 is found at offset 0x04 of the
772 * second packet. This time we received five bytes first and
773 * then the rest. You never know how many bytes you get.
774 *
775 * A typical packet for player version 2.0 (beta):
776 *
777 * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA.............
778 * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux.c..Win2.0.0
779 * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
780 * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
781 * 0040:65 2E 72 61 79 53 00 00 06 36 42 e.rayS...6B
782 *
783 * Port number 0x1BC1 is found at offset 0x0d.
784 *
785 * This is just a horrible switch statement. Variable ra tells
786 * us where we're going.
787 */
788
789 bptr = m->m_datam_hdr.mh_data;
790 while (bptr < m->m_datam_hdr.mh_data + m->m_lenm_hdr.mh_len) {
791 u_short p;
792 static int ra = 0;
793 char ra_tbl[4];
794
795 ra_tbl[0] = 0x50;
796 ra_tbl[1] = 0x4e;
797 ra_tbl[2] = 0x41;
798 ra_tbl[3] = 0;
799
800 switch (ra) {
801 case 0:
802 case 2:
803 case 3:
804 if (*bptr++ != ra_tbl[ra]) {
805 ra = 0;
806 continue;
807 }
808 break;
809
810 case 1:
811 /*
812 * We may get 0x50 several times, ignore them
813 */
814 if (*bptr == 0x50) {
815 ra = 1;
816 bptr++;
817 continue;
818 } else if (*bptr++ != ra_tbl[ra]) {
819 ra = 0;
820 continue;
821 }
822 break;
823
824 case 4:
825 /*
826 * skip version number
827 */
828 bptr++;
829 break;
830
831 case 5:
832 /*
833 * The difference between versions 1.0 and
834 * 2.0 is here. For future versions of
835 * the player this may need to be modified.
836 */
837 if (*(bptr + 1) == 0x02)
838 bptr += 8;
839 else
840 bptr += 4;
841 break;
842
843 case 6:
844 /* This is the field containing the port
845 * number that RA-player is listening to.
846 */
847 lport = (((u_char*)bptr)[0] << 8)
848 + ((u_char *)bptr)[1];
849 if (lport < 6970)
850 lport += 256; /* don't know why */
851 if (lport < 6970 || lport > 7170)
852 return 1; /* failed */
853
854 /* try to get udp port between 6970 - 7170 */
855 for (p = 6970; p < 7071; p++) {
856 if (udp_listen(slirp, INADDR_ANY((in_addr_t) 0x00000000),
857 htons(p),
858 so->so_laddr.s_addr,
859 htons(lport),
860 SS_FACCEPTONCE0x200)) {
861 break;
862 }
863 }
864 if (p == 7071)
865 p = 0;
866 *(u_char *)bptr++ = (p >> 8) & 0xff;
867 *(u_char *)bptr = p & 0xff;
868 ra = 0;
869 return 1; /* port redirected, we're done */
870 break;
871
872 default:
873 ra = 0;
874 }
875 ra++;
876 }
877 return 1;
878
879 default:
880 /* Ooops, not emulated, won't call tcp_emu again */
881 so->so_emu = 0;
882 return 1;
883 }
884}
885
886/*
887 * Do misc. config of SLiRP while its running.
888 * Return 0 if this connections is to be closed, 1 otherwise,
889 * return 2 if this is a command-line connection
890 */
891int tcp_ctl(struct socket *so)
892{
893 Slirp *slirp = so->slirp;
894 struct sbuf *sb = &so->so_snd;
895 struct ex_list *ex_ptr;
896 int do_pty;
897
898 DEBUG_CALL("tcp_ctl");
899 DEBUG_ARG("so = %lx", (long )so);
900
901 if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
902 /* Check if it's pty_exec */
903 for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
904 if (ex_ptr->ex_fport == so->so_fport &&
905 so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
906 if (ex_ptr->ex_pty == 3) {
907 so->s = -1;
908 so->extra = (void *)ex_ptr->ex_exec;
909 return 1;
910 }
911 do_pty = ex_ptr->ex_pty;
912 DEBUG_MISC((dfd, " executing %s\n", ex_ptr->ex_exec));
913 return fork_exec(so, ex_ptr->ex_exec, do_pty);
914 }
915 }
916 }
917 sb->sb_cc =
918 snprintf(sb->sb_wptr, sb->sb_datalen - (sb->sb_wptr - sb->sb_data),
919 "Error: No application configured.\r\n");
920 sb->sb_wptr += sb->sb_cc;
921 return 0;
922}