slirp/tcp_subr.c

   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 "qemu/osdep.h"
  42 #include <slirp.h>
  43
  44 /* patchable/settable parameters for tcp */
  45 /* Don't do rfc1323 performance enhancements */
  46 #define TCP_DO_RFC1323 0
  47
  48 /*
  49  * Tcp initialization
  50  */
  51 void
  52 tcp_init(Slirp *slirp)
  53 {
  54     slirp->tcp_iss = 1;         /* wrong */
  55     slirp->tcb.so_next = slirp->tcb.so_prev = &slirp->tcb;
  56     slirp->tcp_last_so = &slirp->tcb;
  57 }
  58
  59 void tcp_cleanup(Slirp *slirp)
  60 {
  61     while (slirp->tcb.so_next != &slirp->tcb) {
  62         tcp_close(sototcpcb(slirp->tcb.so_next));
  63     }
  64 }
  65
  66 /*
  67  * Create template to be used to send tcp packets on a connection.
  68  * Call after host entry created, fills
  69  * in a skeletal tcp/ip header, minimizing the amount of work
  70  * necessary when the connection is used.
  71  */
  72 void
  73 tcp_template(struct tcpcb *tp)
  74 {
  75         struct socket *so = tp->t_socket;
  76         register struct tcpiphdr *n = &tp->t_template;
  77
  78         n->ti_mbuf = NULL;
  79         n->ti_x1 = 0;
  80         n->ti_pr = IPPROTO_TCP;
  81         n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
  82         n->ti_src = so->so_faddr;
  83         n->ti_dst = so->so_laddr;
  84         n->ti_sport = so->so_fport;
  85         n->ti_dport = so->so_lport;
  86
  87         n->ti_seq = 0;
  88         n->ti_ack = 0;
  89         n->ti_x2 = 0;
  90         n->ti_off = 5;
  91         n->ti_flags = 0;
  92         n->ti_win = 0;
  93         n->ti_sum = 0;
  94         n->ti_urp = 0;
  95 }
  96
  97 /*
  98  * Send a single message to the TCP at address specified by
  99  * the given TCP/IP header.  If m == 0, then we make a copy
 100  * of the tcpiphdr at ti and send directly to the addressed host.
 101  * This is used to force keep alive messages out using the TCP
 102  * template for a connection tp->t_template.  If flags are given
 103  * then we send a message back to the TCP which originated the
 104  * segment ti, and discard the mbuf containing it and any other
 105  * attached mbufs.
 106  *
 107  * In any case the ack and sequence number of the transmitted
 108  * segment are as specified by the parameters.
 109  */
 110 void
 111 tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
 112             tcp_seq ack, tcp_seq seq, int flags)
 113 {
 114         register int tlen;
 115         int win = 0;
 116
 117         DEBUG_CALL("tcp_respond");
 118         DEBUG_ARG("tp = %p", tp);
 119         DEBUG_ARG("ti = %p", ti);
 120         DEBUG_ARG("m = %p", m);
 121         DEBUG_ARG("ack = %u", ack);
 122         DEBUG_ARG("seq = %u", seq);
 123         DEBUG_ARG("flags = %x", flags);
 124
 125         if (tp)
 126                 win = sbspace(&tp->t_socket->so_rcv);
 127         if (m == NULL) {
 128                 if (!tp || (m = m_get(tp->t_socket->slirp)) == NULL)
 129                         return;
 130                 tlen = 0;
 131                 m->m_data += IF_MAXLINKHDR;
 132                 *mtod(m, struct tcpiphdr *) = *ti;
 133                 ti = mtod(m, struct tcpiphdr *);
 134                 flags = TH_ACK;
 135         } else {
 136                 /*
 137                  * ti points into m so the next line is just making
 138                  * the mbuf point to ti
 139                  */
 140                 m->m_data = (caddr_t)ti;
 141
 142                 m->m_len = sizeof (struct tcpiphdr);
 143                 tlen = 0;
 144 #define xchg(a,b,type) { type t; t=a; a=b; b=t; }
 145                 xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, uint32_t);
 146                 xchg(ti->ti_dport, ti->ti_sport, uint16_t);
 147 #undef xchg
 148         }
 149         ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
 150         tlen += sizeof (struct tcpiphdr);
 151         m->m_len = tlen;
 152
 153         ti->ti_mbuf = NULL;
 154         ti->ti_x1 = 0;
 155         ti->ti_seq = htonl(seq);
 156         ti->ti_ack = htonl(ack);
 157         ti->ti_x2 = 0;
 158         ti->ti_off = sizeof (struct tcphdr) >> 2;
 159         ti->ti_flags = flags;
 160         if (tp)
 161                 ti->ti_win = htons((uint16_t) (win >> tp->rcv_scale));
 162         else
 163                 ti->ti_win = htons((uint16_t)win);
 164         ti->ti_urp = 0;
 165         ti->ti_sum = 0;
 166         ti->ti_sum = cksum(m, tlen);
 167         ((struct ip *)ti)->ip_len = tlen;
 168
 169         if(flags & TH_RST)
 170           ((struct ip *)ti)->ip_ttl = MAXTTL;
 171         else
 172           ((struct ip *)ti)->ip_ttl = IPDEFTTL;
 173
 174         (void) ip_output((struct socket *)0, m);
 175 }
 176
 177 /*
 178  * Create a new TCP control block, making an
 179  * empty reassembly queue and hooking it to the argument
 180  * protocol control block.
 181  */
 182 struct tcpcb *
 183 tcp_newtcpcb(struct socket *so)
 184 {
 185         register struct tcpcb *tp;
 186
 187         tp = (struct tcpcb *)malloc(sizeof(*tp));
 188         if (tp == NULL)
 189                 return ((struct tcpcb *)0);
 190
 191         memset((char *) tp, 0, sizeof(struct tcpcb));
 192         tp->seg_next = tp->seg_prev = (struct tcpiphdr*)tp;
 193         tp->t_maxseg = TCP_MSS;
 194
 195         tp->t_flags = TCP_DO_RFC1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0;
 196         tp->t_socket = so;
 197
 198         /*
 199          * Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
 200          * rtt estimate.  Set rttvar so that srtt + 2 * rttvar gives
 201          * reasonable initial retransmit time.
 202          */
 203         tp->t_srtt = TCPTV_SRTTBASE;
 204         tp->t_rttvar = TCPTV_SRTTDFLT << 2;
 205         tp->t_rttmin = TCPTV_MIN;
 206
 207         TCPT_RANGESET(tp->t_rxtcur,
 208             ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
 209             TCPTV_MIN, TCPTV_REXMTMAX);
 210
 211         tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
 212         tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
 213         tp->t_state = TCPS_CLOSED;
 214
 215         so->so_tcpcb = tp;
 216
 217         return (tp);
 218 }
 219
 220 /*
 221  * Drop a TCP connection, reporting
 222  * the specified error.  If connection is synchronized,
 223  * then send a RST to peer.
 224  */
 225 struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
 226 {
 227         DEBUG_CALL("tcp_drop");
 228         DEBUG_ARG("tp = %p", tp);
 229         DEBUG_ARG("errno = %d", errno);
 230
 231         if (TCPS_HAVERCVDSYN(tp->t_state)) {
 232                 tp->t_state = TCPS_CLOSED;
 233                 (void) tcp_output(tp);
 234         }
 235         return (tcp_close(tp));
 236 }
 237
 238 /*
 239  * Close a TCP control block:
 240  *      discard all space held by the tcp
 241  *      discard internet protocol block
 242  *      wake up any sleepers
 243  */
 244 struct tcpcb *
 245 tcp_close(struct tcpcb *tp)
 246 {
 247         register struct tcpiphdr *t;
 248         struct socket *so = tp->t_socket;
 249         Slirp *slirp = so->slirp;
 250         register struct mbuf *m;
 251
 252         DEBUG_CALL("tcp_close");
 253         DEBUG_ARG("tp = %p", tp);
 254
 255         /* free the reassembly queue, if any */
 256         t = tcpfrag_list_first(tp);
 257         while (!tcpfrag_list_end(t, tp)) {
 258                 t = tcpiphdr_next(t);
 259                 m = tcpiphdr_prev(t)->ti_mbuf;
 260                 remque(tcpiphdr2qlink(tcpiphdr_prev(t)));
 261                 m_free(m);
 262         }
 263         free(tp);
 264         so->so_tcpcb = NULL;
 265         /* clobber input socket cache if we're closing the cached connection */
 266         if (so == slirp->tcp_last_so)
 267                 slirp->tcp_last_so = &slirp->tcb;
 268         closesocket(so->s);
 269         sbfree(&so->so_rcv);
 270         sbfree(&so->so_snd);
 271         sofree(so);
 272         return ((struct tcpcb *)0);
 273 }
 274
 275 /*
 276  * TCP protocol interface to socket abstraction.
 277  */
 278
 279 /*
 280  * User issued close, and wish to trail through shutdown states:
 281  * if never received SYN, just forget it.  If got a SYN from peer,
 282  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
 283  * If already got a FIN from peer, then almost done; go to LAST_ACK
 284  * state.  In all other cases, have already sent FIN to peer (e.g.
 285  * after PRU_SHUTDOWN), and just have to play tedious game waiting
 286  * for peer to send FIN or not respond to keep-alives, etc.
 287  * We can let the user exit from the close as soon as the FIN is acked.
 288  */
 289 void
 290 tcp_sockclosed(struct tcpcb *tp)
 291 {
 292
 293         DEBUG_CALL("tcp_sockclosed");
 294         DEBUG_ARG("tp = %p", tp);
 295
 296         switch (tp->t_state) {
 297
 298         case TCPS_CLOSED:
 299         case TCPS_LISTEN:
 300         case TCPS_SYN_SENT:
 301                 tp->t_state = TCPS_CLOSED;
 302                 tp = tcp_close(tp);
 303                 break;
 304
 305         case TCPS_SYN_RECEIVED:
 306         case TCPS_ESTABLISHED:
 307                 tp->t_state = TCPS_FIN_WAIT_1;
 308                 break;
 309
 310         case TCPS_CLOSE_WAIT:
 311                 tp->t_state = TCPS_LAST_ACK;
 312                 break;
 313         }
 314         if (tp)
 315                 tcp_output(tp);
 316 }
 317
 318 /*
 319  * Connect to a host on the Internet
 320  * Called by tcp_input
 321  * Only do a connect, the tcp fields will be set in tcp_input
 322  * return 0 if there's a result of the connect,
 323  * else return -1 means we're still connecting
 324  * The return value is almost always -1 since the socket is
 325  * nonblocking.  Connect returns after the SYN is sent, and does
 326  * not wait for ACK+SYN.
 327  */
 328 int tcp_fconnect(struct socket *so, unsigned short af)
 329 {
 330   int ret=0;
 331
 332   DEBUG_CALL("tcp_fconnect");
 333   DEBUG_ARG("so = %p", so);
 334
 335   ret = so->s = qemu_socket(af, SOCK_STREAM, 0);
 336   if (ret >= 0) {
 337     int opt, s=so->s;
 338     struct sockaddr_storage addr;
 339
 340     qemu_set_nonblock(s);
 341     socket_set_fast_reuse(s);
 342     opt = 1;
 343     qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 344
 345     addr = so->fhost.ss;
 346     DEBUG_CALL(" connect()ing")
 347     sotranslate_out(so, &addr);
 348
 349     /* We don't care what port we get */
 350     ret = connect(s,(struct sockaddr *)&addr,sizeof (addr));
 351
 352     /*
 353      * If it's not in progress, it failed, so we just return 0,
 354      * without clearing SS_NOFDREF
 355      */
 356     soisfconnecting(so);
 357   }
 358
 359   return(ret);
 360 }
 361
 362 /*
 363  * Accept the socket and connect to the local-host
 364  *
 365  * We have a problem. The correct thing to do would be
 366  * to first connect to the local-host, and only if the
 367  * connection is accepted, then do an accept() here.
 368  * But, a) we need to know who's trying to connect
 369  * to the socket to be able to SYN the local-host, and
 370  * b) we are already connected to the foreign host by
 371  * the time it gets to accept(), so... We simply accept
 372  * here and SYN the local-host.
 373  */
 374 void tcp_connect(struct socket *inso)
 375 {
 376     Slirp *slirp = inso->slirp;
 377     struct socket *so;
 378     struct sockaddr_in addr;
 379     socklen_t addrlen = sizeof(struct sockaddr_in);
 380     struct tcpcb *tp;
 381     int s, opt;
 382
 383     DEBUG_CALL("tcp_connect");
 384     DEBUG_ARG("inso = %p", inso);
 385
 386     /*
 387      * If it's an SS_ACCEPTONCE socket, no need to socreate()
 388      * another socket, just use the accept() socket.
 389      */
 390     if (inso->so_state & SS_FACCEPTONCE) {
 391         /* FACCEPTONCE already have a tcpcb */
 392         so = inso;
 393     } else {
 394         so = socreate(slirp);
 395         if (so == NULL) {
 396             /* If it failed, get rid of the pending connection */
 397             closesocket(accept(inso->s, (struct sockaddr *)&addr, &addrlen));
 398             return;
 399         }
 400         if (tcp_attach(so) < 0) {
 401             free(so); /* NOT sofree */
 402             return;
 403         }
 404         so->so_lfamily = AF_INET;
 405         so->so_laddr = inso->so_laddr;
 406         so->so_lport = inso->so_lport;
 407     }
 408
 409     tcp_mss(sototcpcb(so), 0);
 410
 411     s = accept(inso->s, (struct sockaddr *)&addr, &addrlen);
 412     if (s < 0) {
 413         tcp_close(sototcpcb(so)); /* This will sofree() as well */
 414         return;
 415     }
 416     qemu_set_nonblock(s);
 417     socket_set_fast_reuse(s);
 418     opt = 1;
 419     qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
 420     socket_set_nodelay(s);
 421
 422     so->fhost.sin = addr;
 423     sotranslate_accept(so);
 424
 425     /* Close the accept() socket, set right state */
 426     if (inso->so_state & SS_FACCEPTONCE) {
 427         /* If we only accept once, close the accept() socket */
 428         closesocket(so->s);
 429
 430         /* Don't select it yet, even though we have an FD */
 431         /* if it's not FACCEPTONCE, it's already NOFDREF */
 432         so->so_state = SS_NOFDREF;
 433     }
 434     so->s = s;
 435     so->so_state |= SS_INCOMING;
 436
 437     so->so_iptos = tcp_tos(so);
 438     tp = sototcpcb(so);
 439
 440     tcp_template(tp);
 441
 442     tp->t_state = TCPS_SYN_SENT;
 443     tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
 444     tp->iss = slirp->tcp_iss;
 445     slirp->tcp_iss += TCP_ISSINCR/2;
 446     tcp_sendseqinit(tp);
 447     tcp_output(tp);
 448 }
 449
 450 /*
 451  * Attach a TCPCB to a socket.
 452  */
 453 int
 454 tcp_attach(struct socket *so)
 455 {
 456         if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
 457            return -1;
 458
 459         insque(so, &so->slirp->tcb);
 460
 461         return 0;
 462 }
 463
 464 /*
 465  * Set the socket's type of service field
 466  */
 467 static const struct tos_t tcptos[] = {
 468           {0, 20, IPTOS_THROUGHPUT, 0}, /* ftp data */
 469           {21, 21, IPTOS_LOWDELAY,  EMU_FTP},   /* ftp control */
 470           {0, 23, IPTOS_LOWDELAY, 0},   /* telnet */
 471           {0, 80, IPTOS_THROUGHPUT, 0}, /* WWW */
 472           {0, 513, IPTOS_LOWDELAY, EMU_RLOGIN|EMU_NOCONNECT},   /* rlogin */
 473           {0, 514, IPTOS_LOWDELAY, EMU_RSH|EMU_NOCONNECT},      /* shell */
 474           {0, 544, IPTOS_LOWDELAY, EMU_KSH},            /* kshell */
 475           {0, 543, IPTOS_LOWDELAY, 0},  /* klogin */
 476           {0, 6667, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC */
 477           {0, 6668, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC undernet */
 478           {0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
 479           {0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
 480           {0, 0, 0, 0}
 481 };
 482
 483 static struct emu_t *tcpemu = NULL;
 484
 485 /*
 486  * Return TOS according to the above table
 487  */
 488 uint8_t
 489 tcp_tos(struct socket *so)
 490 {
 491         int i = 0;
 492         struct emu_t *emup;
 493
 494         while(tcptos[i].tos) {
 495                 if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
 496                     (tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
 497                         so->so_emu = tcptos[i].emu;
 498                         return tcptos[i].tos;
 499                 }
 500                 i++;
 501         }
 502
 503         /* Nope, lets see if there's a user-added one */
 504         for (emup = tcpemu; emup; emup = emup->next) {
 505                 if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
 506                     (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
 507                         so->so_emu = emup->emu;
 508                         return emup->tos;
 509                 }
 510         }
 511
 512         return 0;
 513 }
 514
 515 /*
 516  * Emulate programs that try and connect to us
 517  * This includes ftp (the data connection is
 518  * initiated by the server) and IRC (DCC CHAT and
 519  * DCC SEND) for now
 520  *
 521  * NOTE: It's possible to crash SLiRP by sending it
 522  * unstandard strings to emulate... if this is a problem,
 523  * more checks are needed here
 524  *
 525  * XXX Assumes the whole command came in one packet
 526  *
 527  * XXX Some ftp clients will have their TOS set to
 528  * LOWDELAY and so Nagel will kick in.  Because of this,
 529  * we'll get the first letter, followed by the rest, so
 530  * we simply scan for ORT instead of PORT...
 531  * DCC doesn't have this problem because there's other stuff
 532  * in the packet before the DCC command.
 533  *
 534  * Return 1 if the mbuf m is still valid and should be
 535  * sbappend()ed
 536  *
 537  * NOTE: if you return 0 you MUST m_free() the mbuf!
 538  */
 539 int
 540 tcp_emu(struct socket *so, struct mbuf *m)
 541 {
 542         Slirp *slirp = so->slirp;
 543         u_int n1, n2, n3, n4, n5, n6;
 544         char buff[257];
 545         uint32_t laddr;
 546         u_int lport;
 547         char *bptr;
 548
 549         DEBUG_CALL("tcp_emu");
 550         DEBUG_ARG("so = %p", so);
 551         DEBUG_ARG("m = %p", m);
 552
 553         switch(so->so_emu) {
 554                 int x, i;
 555
 556          case EMU_IDENT:
 557                 /*
 558                  * Identification protocol as per rfc-1413
 559                  */
 560
 561                 {
 562                         struct socket *tmpso;
 563                         struct sockaddr_in addr;
 564                         socklen_t addrlen = sizeof(struct sockaddr_in);
 565                         struct sbuf *so_rcv = &so->so_rcv;
 566
 567                         memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
 568                         so_rcv->sb_wptr += m->m_len;
 569                         so_rcv->sb_rptr += m->m_len;
 570                         m->m_data[m->m_len] = 0; /* NULL terminate */
 571                         if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
 572                                 if (sscanf(so_rcv->sb_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
 573                                         HTONS(n1);
 574                                         HTONS(n2);
 575                                         /* n2 is the one on our host */
 576                                         for (tmpso = slirp->tcb.so_next;
 577                                              tmpso != &slirp->tcb;
 578                                              tmpso = tmpso->so_next) {
 579                                                 if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
 580                                                     tmpso->so_lport == n2 &&
 581                                                     tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
 582                                                     tmpso->so_fport == n1) {
 583                                                         if (getsockname(tmpso->s,
 584                                                                 (struct sockaddr *)&addr, &addrlen) == 0)
 585                                                            n2 = ntohs(addr.sin_port);
 586                                                         break;
 587                                                 }
 588                                         }
 589                                 }
 590                                 so_rcv->sb_cc = snprintf(so_rcv->sb_data,
 591                                                          so_rcv->sb_datalen,
 592                                                          "%d,%d\r\n", n1, n2);
 593                                 so_rcv->sb_rptr = so_rcv->sb_data;
 594                                 so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
 595                         }
 596                         m_free(m);
 597                         return 0;
 598                 }
 599
 600         case EMU_FTP: /* ftp */
 601                 *(m->m_data+m->m_len) = 0; /* NUL terminate for strstr */
 602                 if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
 603                         /*
 604                          * Need to emulate the PORT command
 605                          */
 606                         x = sscanf(bptr, "ORT %u,%u,%u,%u,%u,%u\r\n%256[^\177]",
 607                                    &n1, &n2, &n3, &n4, &n5, &n6, buff);
 608                         if (x < 6)
 609                            return 1;
 610
 611                         laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
 612                         lport = htons((n5 << 8) | (n6));
 613
 614                         if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr,
 615                                              lport, SS_FACCEPTONCE)) == NULL) {
 616                            return 1;
 617                         }
 618                         n6 = ntohs(so->so_fport);
 619
 620                         n5 = (n6 >> 8) & 0xff;
 621                         n6 &= 0xff;
 622
 623                         laddr = ntohl(so->so_faddr.s_addr);
 624
 625                         n1 = ((laddr >> 24) & 0xff);
 626                         n2 = ((laddr >> 16) & 0xff);
 627                         n3 = ((laddr >> 8)  & 0xff);
 628                         n4 =  (laddr & 0xff);
 629
 630                         m->m_len = bptr - m->m_data; /* Adjust length */
 631                         m->m_len += snprintf(bptr, m->m_size - m->m_len,
 632                                              "ORT %d,%d,%d,%d,%d,%d\r\n%s",
 633                                              n1, n2, n3, n4, n5, n6, x==7?buff:"");
 634                         return 1;
 635                 } else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
 636                         /*
 637                          * Need to emulate the PASV response
 638                          */
 639                         x = sscanf(bptr, "27 Entering Passive Mode (%u,%u,%u,%u,%u,%u)\r\n%256[^\177]",
 640                                    &n1, &n2, &n3, &n4, &n5, &n6, buff);
 641                         if (x < 6)
 642                            return 1;
 643
 644                         laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
 645                         lport = htons((n5 << 8) | (n6));
 646
 647                         if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr,
 648                                              lport, SS_FACCEPTONCE)) == NULL) {
 649                            return 1;
 650                         }
 651                         n6 = ntohs(so->so_fport);
 652
 653                         n5 = (n6 >> 8) & 0xff;
 654                         n6 &= 0xff;
 655
 656                         laddr = ntohl(so->so_faddr.s_addr);
 657
 658                         n1 = ((laddr >> 24) & 0xff);
 659                         n2 = ((laddr >> 16) & 0xff);
 660                         n3 = ((laddr >> 8)  & 0xff);
 661                         n4 =  (laddr & 0xff);
 662
 663                         m->m_len = bptr - m->m_data; /* Adjust length */
 664                         m->m_len += snprintf(bptr, m->m_size - m->m_len,
 665                                              "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
 666                                              n1, n2, n3, n4, n5, n6, x==7?buff:"");
 667
 668                         return 1;
 669                 }
 670
 671                 return 1;
 672
 673          case EMU_KSH:
 674                 /*
 675                  * The kshell (Kerberos rsh) and shell services both pass
 676                  * a local port port number to carry signals to the server
 677                  * and stderr to the client.  It is passed at the beginning
 678                  * of the connection as a NUL-terminated decimal ASCII string.
 679                  */
 680                 so->so_emu = 0;
 681                 for (lport = 0, i = 0; i < m->m_len-1; ++i) {
 682                         if (m->m_data[i] < '0' || m->m_data[i] > '9')
 683                                 return 1;       /* invalid number */
 684                         lport *= 10;
 685                         lport += m->m_data[i] - '0';
 686                 }
 687                 if (m->m_data[m->m_len-1] == '\0' && lport != 0 &&
 688                     (so = tcp_listen(slirp, INADDR_ANY, 0, so->so_laddr.s_addr,
 689                                      htons(lport), SS_FACCEPTONCE)) != NULL)
 690                     m->m_len = snprintf(m->m_data, m->m_size, "%d",
 691                                         ntohs(so->so_fport)) + 1;
 692                 return 1;
 693
 694          case EMU_IRC:
 695                 /*
 696                  * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
 697                  */
 698                 *(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
 699                 if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
 700                          return 1;
 701
 702                 /* The %256s is for the broken mIRC */
 703                 if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
 704                         if ((so = tcp_listen(slirp, INADDR_ANY, 0,
 705                                              htonl(laddr), htons(lport),
 706                                              SS_FACCEPTONCE)) == NULL) {
 707                                 return 1;
 708                         }
 709                         m->m_len = bptr - m->m_data; /* Adjust length */
 710                         m->m_len += snprintf(bptr, m->m_size,
 711                                              "DCC CHAT chat %lu %u%c\n",
 712                                              (unsigned long)ntohl(so->so_faddr.s_addr),
 713                                              ntohs(so->so_fport), 1);
 714                 } else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
 715                         if ((so = tcp_listen(slirp, INADDR_ANY, 0,
 716                                              htonl(laddr), htons(lport),
 717                                              SS_FACCEPTONCE)) == NULL) {
 718                                 return 1;
 719                         }
 720                         m->m_len = bptr - m->m_data; /* Adjust length */
 721                         m->m_len += snprintf(bptr, m->m_size,
 722                                              "DCC SEND %s %lu %u %u%c\n", buff,
 723                                              (unsigned long)ntohl(so->so_faddr.s_addr),
 724                                              ntohs(so->so_fport), n1, 1);
 725                 } else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
 726                         if ((so = tcp_listen(slirp, INADDR_ANY, 0,
 727                                              htonl(laddr), htons(lport),
 728                                              SS_FACCEPTONCE)) == NULL) {
 729                                 return 1;
 730                         }
 731                         m->m_len = bptr - m->m_data; /* Adjust length */
 732                         m->m_len += snprintf(bptr, m->m_size,
 733                                              "DCC MOVE %s %lu %u %u%c\n", buff,
 734                                              (unsigned long)ntohl(so->so_faddr.s_addr),
 735                                              ntohs(so->so_fport), n1, 1);
 736                 }
 737                 return 1;
 738
 739          case EMU_REALAUDIO:
 740                 /*
 741                  * RealAudio emulation - JP. We must try to parse the incoming
 742                  * data and try to find the two characters that contain the
 743                  * port number. Then we redirect an udp port and replace the
 744                  * number with the real port we got.
 745                  *
 746                  * The 1.0 beta versions of the player are not supported
 747                  * any more.
 748                  *
 749                  * A typical packet for player version 1.0 (release version):
 750                  *
 751                  * 0000:50 4E 41 00 05
 752                  * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 ........g.l.c..P
 753                  * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
 754                  * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
 755                  * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
 756                  *
 757                  * Now the port number 0x1BD7 is found at offset 0x04 of the
 758                  * Now the port number 0x1BD7 is found at offset 0x04 of the
 759                  * second packet. This time we received five bytes first and
 760                  * then the rest. You never know how many bytes you get.
 761                  *
 762                  * A typical packet for player version 2.0 (beta):
 763                  *
 764                  * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA.............
 765                  * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux.c..Win2.0.0
 766                  * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
 767                  * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
 768                  * 0040:65 2E 72 61 79 53 00 00 06 36 42                e.rayS...6B
 769                  *
 770                  * Port number 0x1BC1 is found at offset 0x0d.
 771                  *
 772                  * This is just a horrible switch statement. Variable ra tells
 773                  * us where we're going.
 774                  */
 775
 776                 bptr = m->m_data;
 777                 while (bptr < m->m_data + m->m_len) {
 778                         u_short p;
 779                         static int ra = 0;
 780                         char ra_tbl[4];
 781
 782                         ra_tbl[0] = 0x50;
 783                         ra_tbl[1] = 0x4e;
 784                         ra_tbl[2] = 0x41;
 785                         ra_tbl[3] = 0;
 786
 787                         switch (ra) {
 788                          case 0:
 789                          case 2:
 790                          case 3:
 791                                 if (*bptr++ != ra_tbl[ra]) {
 792                                         ra = 0;
 793                                         continue;
 794                                 }
 795                                 break;
 796
 797                          case 1:
 798                                 /*
 799                                  * We may get 0x50 several times, ignore them
 800                                  */
 801                                 if (*bptr == 0x50) {
 802                                         ra = 1;
 803                                         bptr++;
 804                                         continue;
 805                                 } else if (*bptr++ != ra_tbl[ra]) {
 806                                         ra = 0;
 807                                         continue;
 808                                 }
 809                                 break;
 810
 811                          case 4:
 812                                 /*
 813                                  * skip version number
 814                                  */
 815                                 bptr++;
 816                                 break;
 817
 818                          case 5:
 819                                 /*
 820                                  * The difference between versions 1.0 and
 821                                  * 2.0 is here. For future versions of
 822                                  * the player this may need to be modified.
 823                                  */
 824                                 if (*(bptr + 1) == 0x02)
 825                                    bptr += 8;
 826                                 else
 827                                    bptr += 4;
 828                                 break;
 829
 830                          case 6:
 831                                 /* This is the field containing the port
 832                                  * number that RA-player is listening to.
 833                                  */
 834                                 lport = (((u_char*)bptr)[0] << 8)
 835                                 + ((u_char *)bptr)[1];
 836                                 if (lport < 6970)
 837                                    lport += 256;   /* don't know why */
 838                                 if (lport < 6970 || lport > 7170)
 839                                    return 1;       /* failed */
 840
 841                                 /* try to get udp port between 6970 - 7170 */
 842                                 for (p = 6970; p < 7071; p++) {
 843                                         if (udp_listen(slirp, INADDR_ANY,
 844                                                        htons(p),
 845                                                        so->so_laddr.s_addr,
 846                                                        htons(lport),
 847                                                        SS_FACCEPTONCE)) {
 848                                                 break;
 849                                         }
 850                                 }
 851                                 if (p == 7071)
 852                                    p = 0;
 853                                 *(u_char *)bptr++ = (p >> 8) & 0xff;
 854                                 *(u_char *)bptr = p & 0xff;
 855                                 ra = 0;
 856                                 return 1;   /* port redirected, we're done */
 857                                 break;
 858
 859                          default:
 860                                 ra = 0;
 861                         }
 862                         ra++;
 863                 }
 864                 return 1;
 865
 866          default:
 867                 /* Ooops, not emulated, won't call tcp_emu again */
 868                 so->so_emu = 0;
 869                 return 1;
 870         }
 871 }
 872
 873 /*
 874  * Do misc. config of SLiRP while its running.
 875  * Return 0 if this connections is to be closed, 1 otherwise,
 876  * return 2 if this is a command-line connection
 877  */
 878 int tcp_ctl(struct socket *so)
 879 {
 880     Slirp *slirp = so->slirp;
 881     struct sbuf *sb = &so->so_snd;
 882     struct ex_list *ex_ptr;
 883     int do_pty;
 884
 885     DEBUG_CALL("tcp_ctl");
 886     DEBUG_ARG("so = %p", so);
 887
 888     if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
 889         /* Check if it's pty_exec */
 890         for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
 891             if (ex_ptr->ex_fport == so->so_fport &&
 892                 so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
 893                 if (ex_ptr->ex_pty == 3) {
 894                     so->s = -1;
 895                     so->extra = (void *)ex_ptr->ex_exec;
 896                     return 1;
 897                 }
 898                 do_pty = ex_ptr->ex_pty;
 899                 DEBUG_MISC((dfd, " executing %s\n", ex_ptr->ex_exec));
 900                 return fork_exec(so, ex_ptr->ex_exec, do_pty);
 901             }
 902         }
 903     }
 904     sb->sb_cc =
 905         snprintf(sb->sb_wptr, sb->sb_datalen - (sb->sb_wptr - sb->sb_data),
 906                  "Error: No application configured.\r\n");
 907     sb->sb_wptr += sb->sb_cc;
 908     return 0;
 909 }