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 <slirp.h>
  42
  43 /* patchable/settable parameters for tcp */
  44 /* Don't do rfc1323 performance enhancements */
  45 #define TCP_DO_RFC1323 0
  46
  47 /*
  48  * Tcp initialization
  49  */
  50 void
  51 tcp_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
  58 void tcp_cleanup(Slirp *slirp)
  59 {
  60     while (slirp->tcb.so_next != &slirp->tcb) {
  61         tcp_close(sototcpcb(slirp->tcb.so_next));
  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  */
  71 void
  72 tcp_template(struct tcpcb *tp)
  73 {
  74         struct socket *so = tp->t_socket;
  75         register struct tcpiphdr *n = &tp->t_template;
  76
  77         n->ti_mbuf = NULL;
  78         n->ti_x1 = 0;
  79         n->ti_pr = IPPROTO_TCP;
  80         n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
  81         n->ti_src = so->so_faddr;
  82         n->ti_dst = so->so_laddr;
  83         n->ti_sport = so->so_fport;
  84         n->ti_dport = so->so_lport;
  85
  86         n->ti_seq = 0;
  87         n->ti_ack = 0;
  88         n->ti_x2 = 0;
  89         n->ti_off = 5;
  90         n->ti_flags = 0;
  91         n->ti_win = 0;
  92         n->ti_sum = 0;
  93         n->ti_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  */
 109 void
 110 tcp_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 = %p", tp);
 118         DEBUG_ARG("ti = %p", ti);
 119         DEBUG_ARG("m = %p", m);
 120         DEBUG_ARG("ack = %u", ack);
 121         DEBUG_ARG("seq = %u", seq);
 122         DEBUG_ARG("flags = %x", flags);
 123
 124         if (tp)
 125                 win = sbspace(&tp->t_socket->so_rcv);
 126         if (m == NULL) {
 127                 if (!tp || (m = m_get(tp->t_socket->slirp)) == NULL)
 128                         return;
 129                 tlen = 0;
 130                 m->m_data += IF_MAXLINKHDR;
 131                 *mtod(m, struct tcpiphdr *) = *ti;
 132                 ti = mtod(m, struct tcpiphdr *);
 133                 flags = TH_ACK;
 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_data = (caddr_t)ti;
 140
 141                 m->m_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_dst.s_addr, ti->ti_src.s_addr, uint32_t);
 145                 xchg(ti->ti_dport, ti->ti_sport, uint16_t);
 146 #undef xchg
 147         }
 148         ti->ti_len = htons((u_short)(sizeof (struct tcphdr) + tlen));
 149         tlen += sizeof (struct tcpiphdr);
 150         m->m_len = tlen;
 151
 152         ti->ti_mbuf = NULL;
 153         ti->ti_x1 = 0;
 154         ti->ti_seq = htonl(seq);
 155         ti->ti_ack = htonl(ack);
 156         ti->ti_x2 = 0;
 157         ti->ti_off = sizeof (struct tcphdr) >> 2;
 158         ti->ti_flags = flags;
 159         if (tp)
 160                 ti->ti_win = htons((uint16_t) (win >> tp->rcv_scale));
 161         else
 162                 ti->ti_win = htons((uint16_t)win);
 163         ti->ti_urp = 0;
 164         ti->ti_sum = 0;
 165         ti->ti_sum = cksum(m, tlen);
 166         ((struct ip *)ti)->ip_len = tlen;
 167
 168         if(flags & TH_RST)
 169           ((struct ip *)ti)->ip_ttl = MAXTTL;
 170         else
 171           ((struct ip *)ti)->ip_ttl = IPDEFTTL;
 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  */
 181 struct tcpcb *
 182 tcp_newtcpcb(struct socket *so)
 183 {
 184         register struct tcpcb *tp;
 185
 186         tp = (struct tcpcb *)malloc(sizeof(*tp));
 187         if (tp == NULL)
 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_MSS;
 193
 194         tp->t_flags = TCP_DO_RFC1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 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_SRTTBASE;
 203         tp->t_rttvar = TCPTV_SRTTDFLT << 2;
 204         tp->t_rttmin = TCPTV_MIN;
 205
 206         TCPT_RANGESET(tp->t_rxtcur,
 207             ((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
 208             TCPTV_MIN, TCPTV_REXMTMAX);
 209
 210         tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
 211         tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
 212         tp->t_state = TCPS_CLOSED;
 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  */
 224 struct 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)) {
 231                 tp->t_state = TCPS_CLOSED;
 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  */
 243 struct tcpcb *
 244 tcp_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);
 256         while (!tcpfrag_list_end(t, tp)) {
 257                 t = tcpiphdr_next(t);
 258                 m = tcpiphdr_prev(t)->ti_mbuf;
 259                 remque(tcpiphdr2qlink(tcpiphdr_prev(t)));
 260                 m_free(m);
 261         }
 262         free(tp);
 263         so->so_tcpcb = NULL;
 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);
 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  */
 288 void
 289 tcp_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_CLOSED:
 298         case TCPS_LISTEN:
 299         case TCPS_SYN_SENT:
 300                 tp->t_state = TCPS_CLOSED;
 301                 tp = tcp_close(tp);
 302                 break;
 303
 304         case TCPS_SYN_RECEIVED:
 305         case TCPS_ESTABLISHED:
 306                 tp->t_state = TCPS_FIN_WAIT_1;
 307                 break;
 308
 309         case TCPS_CLOSE_WAIT:
 310                 tp->t_state = TCPS_LAST_ACK;
 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  */
 327 int 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_INET,SOCK_STREAM,0)) >= 0) {
 336     int opt, s=so->s;
 337     struct sockaddr_in addr;
 338
 339     qemu_set_nonblock(s);
 340     opt = 1;
 341     qemu_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
 342     opt = 1;
 343     qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 344
 345     addr.sin_family = AF_INET;
 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  */
 387 void tcp_connect(struct socket *inso)
 388 {
 389     Slirp *slirp = inso->slirp;
 390     struct socket *so;
 391     struct sockaddr_in addr;
 392     socklen_t addrlen = sizeof(struct sockaddr_in);
 393     struct tcpcb *tp;
 394     int s, opt;
 395
 396     DEBUG_CALL("tcp_connect");
 397     DEBUG_ARG("inso = %lx", (long)inso);
 398
 399     /*
 400      * If it's an SS_ACCEPTONCE socket, no need to socreate()
 401      * another socket, just use the accept() socket.
 402      */
 403     if (inso->so_state & SS_FACCEPTONCE) {
 404         /* FACCEPTONCE already have a tcpcb */
 405         so = inso;
 406     } else {
 407         so = socreate(slirp);
 408         if (so == NULL) {
 409             /* If it failed, get rid of the pending connection */
 410             closesocket(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     tcp_mss(sototcpcb(so), 0);
 422
 423     s = accept(inso->s, (struct sockaddr *)&addr, &addrlen);
 424     if (s < 0) {
 425         tcp_close(sototcpcb(so)); /* This will sofree() as well */
 426         return;
 427     }
 428     qemu_set_nonblock(s);
 429     opt = 1;
 430     qemu_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int));
 431     opt = 1;
 432     qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
 433     socket_set_nodelay(s);
 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 ||
 439         (so->so_faddr.s_addr & loopback_mask) ==
 440         (loopback_addr.s_addr & loopback_mask)) {
 441         so->so_faddr = slirp->vhost_addr;
 442     }
 443
 444     /* Close the accept() socket, set right state */
 445     if (inso->so_state & SS_FACCEPTONCE) {
 446         /* If we only accept once, close the accept() socket */
 447         closesocket(so->s);
 448
 449         /* Don't select it yet, even though we have an FD */
 450         /* if it's not FACCEPTONCE, it's already NOFDREF */
 451         so->so_state = SS_NOFDREF;
 452     }
 453     so->s = s;
 454     so->so_state |= SS_INCOMING;
 455
 456     so->so_iptos = tcp_tos(so);
 457     tp = sototcpcb(so);
 458
 459     tcp_template(tp);
 460
 461     tp->t_state = TCPS_SYN_SENT;
 462     tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
 463     tp->iss = slirp->tcp_iss;
 464     slirp->tcp_iss += TCP_ISSINCR/2;
 465     tcp_sendseqinit(tp);
 466     tcp_output(tp);
 467 }
 468
 469 /*
 470  * Attach a TCPCB to a socket.
 471  */
 472 int
 473 tcp_attach(struct socket *so)
 474 {
 475         if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
 476            return -1;
 477
 478         insque(so, &so->slirp->tcb);
 479
 480         return 0;
 481 }
 482
 483 /*
 484  * Set the socket's type of service field
 485  */
 486 static const struct tos_t tcptos[] = {
 487           {0, 20, IPTOS_THROUGHPUT, 0}, /* ftp data */
 488           {21, 21, IPTOS_LOWDELAY,  EMU_FTP},   /* ftp control */
 489           {0, 23, IPTOS_LOWDELAY, 0},   /* telnet */
 490           {0, 80, IPTOS_THROUGHPUT, 0}, /* WWW */
 491           {0, 513, IPTOS_LOWDELAY, EMU_RLOGIN|EMU_NOCONNECT},   /* rlogin */
 492           {0, 514, IPTOS_LOWDELAY, EMU_RSH|EMU_NOCONNECT},      /* shell */
 493           {0, 544, IPTOS_LOWDELAY, EMU_KSH},            /* kshell */
 494           {0, 543, IPTOS_LOWDELAY, 0},  /* klogin */
 495           {0, 6667, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC */
 496           {0, 6668, IPTOS_THROUGHPUT, EMU_IRC}, /* IRC undernet */
 497           {0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
 498           {0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
 499           {0, 0, 0, 0}
 500 };
 501
 502 static struct emu_t *tcpemu = NULL;
 503
 504 /*
 505  * Return TOS according to the above table
 506  */
 507 uint8_t
 508 tcp_tos(struct socket *so)
 509 {
 510         int i = 0;
 511         struct emu_t *emup;
 512
 513         while(tcptos[i].tos) {
 514                 if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
 515                     (tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
 516                         so->so_emu = tcptos[i].emu;
 517                         return tcptos[i].tos;
 518                 }
 519                 i++;
 520         }
 521
 522         /* Nope, lets see if there's a user-added one */
 523         for (emup = tcpemu; emup; emup = emup->next) {
 524                 if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
 525                     (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
 526                         so->so_emu = emup->emu;
 527                         return emup->tos;
 528                 }
 529         }
 530
 531         return 0;
 532 }
 533
 534 /*
 535  * Emulate programs that try and connect to us
 536  * This includes ftp (the data connection is
 537  * initiated by the server) and IRC (DCC CHAT and
 538  * DCC SEND) for now
 539  *
 540  * NOTE: It's possible to crash SLiRP by sending it
 541  * unstandard strings to emulate... if this is a problem,
 542  * more checks are needed here
 543  *
 544  * XXX Assumes the whole command came in one packet
 545  *
 546  * XXX Some ftp clients will have their TOS set to
 547  * LOWDELAY and so Nagel will kick in.  Because of this,
 548  * we'll get the first letter, followed by the rest, so
 549  * we simply scan for ORT instead of PORT...
 550  * DCC doesn't have this problem because there's other stuff
 551  * in the packet before the DCC command.
 552  *
 553  * Return 1 if the mbuf m is still valid and should be
 554  * sbappend()ed
 555  *
 556  * NOTE: if you return 0 you MUST m_free() the mbuf!
 557  */
 558 int
 559 tcp_emu(struct socket *so, struct mbuf *m)
 560 {
 561         Slirp *slirp = so->slirp;
 562         u_int n1, n2, n3, n4, n5, n6;
 563         char buff[257];
 564         uint32_t laddr;
 565         u_int lport;
 566         char *bptr;
 567
 568         DEBUG_CALL("tcp_emu");
 569         DEBUG_ARG("so = %lx", (long)so);
 570         DEBUG_ARG("m = %lx", (long)m);
 571
 572         switch(so->so_emu) {
 573                 int x, i;
 574
 575          case EMU_IDENT:
 576                 /*
 577                  * Identification protocol as per rfc-1413
 578                  */
 579
 580                 {
 581                         struct socket *tmpso;
 582                         struct sockaddr_in addr;
 583                         socklen_t addrlen = sizeof(struct sockaddr_in);
 584                         struct sbuf *so_rcv = &so->so_rcv;
 585
 586                         memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
 587                         so_rcv->sb_wptr += m->m_len;
 588                         so_rcv->sb_rptr += m->m_len;
 589                         m->m_data[m->m_len] = 0; /* NULL terminate */
 590                         if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
 591                                 if (sscanf(so_rcv->sb_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
 592                                         HTONS(n1);
 593                                         HTONS(n2);
 594                                         /* n2 is the one on our host */
 595                                         for (tmpso = slirp->tcb.so_next;
 596                                              tmpso != &slirp->tcb;
 597                                              tmpso = tmpso->so_next) {
 598                                                 if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
 599                                                     tmpso->so_lport == n2 &&
 600                                                     tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
 601                                                     tmpso->so_fport == n1) {
 602                                                         if (getsockname(tmpso->s,
 603                                                                 (struct sockaddr *)&addr, &addrlen) == 0)
 604                                                            n2 = ntohs(addr.sin_port);
 605                                                         break;
 606                                                 }
 607                                         }
 608                                 }
 609                                 so_rcv->sb_cc = snprintf(so_rcv->sb_data,
 610                                                          so_rcv->sb_datalen,
 611                                                          "%d,%d\r\n", n1, n2);
 612                                 so_rcv->sb_rptr = so_rcv->sb_data;
 613                                 so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
 614                         }
 615                         m_free(m);
 616                         return 0;
 617                 }
 618
 619         case EMU_FTP: /* ftp */
 620                 *(m->m_data+m->m_len) = 0; /* NUL terminate for strstr */
 621                 if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
 622                         /*
 623                          * Need to emulate the PORT command
 624                          */
 625                         x = sscanf(bptr, "ORT %u,%u,%u,%u,%u,%u\r\n%256[^\177]",
 626                                    &n1, &n2, &n3, &n4, &n5, &n6, buff);
 627                         if (x < 6)
 628                            return 1;
 629
 630                         laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
 631                         lport = htons((n5 << 8) | (n6));
 632
 633                         if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr,
 634                                              lport, SS_FACCEPTONCE)) == NULL) {
 635                            return 1;
 636                         }
 637                         n6 = ntohs(so->so_fport);
 638
 639                         n5 = (n6 >> 8) & 0xff;
 640                         n6 &= 0xff;
 641
 642                         laddr = ntohl(so->so_faddr.s_addr);
 643
 644                         n1 = ((laddr >> 24) & 0xff);
 645                         n2 = ((laddr >> 16) & 0xff);
 646                         n3 = ((laddr >> 8)  & 0xff);
 647                         n4 =  (laddr & 0xff);
 648
 649                         m->m_len = bptr - m->m_data; /* Adjust length */
 650                         m->m_len += snprintf(bptr, m->m_hdr.mh_size - m->m_len,
 651                                              "ORT %d,%d,%d,%d,%d,%d\r\n%s",
 652                                              n1, n2, n3, n4, n5, n6, x==7?buff:"");
 653                         return 1;
 654                 } else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
 655                         /*
 656                          * Need to emulate the PASV response
 657                          */
 658                         x = sscanf(bptr, "27 Entering Passive Mode (%u,%u,%u,%u,%u,%u)\r\n%256[^\177]",
 659                                    &n1, &n2, &n3, &n4, &n5, &n6, buff);
 660                         if (x < 6)
 661                            return 1;
 662
 663                         laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
 664                         lport = htons((n5 << 8) | (n6));
 665
 666                         if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr,
 667                                              lport, SS_FACCEPTONCE)) == NULL) {
 668                            return 1;
 669                         }
 670                         n6 = ntohs(so->so_fport);
 671
 672                         n5 = (n6 >> 8) & 0xff;
 673                         n6 &= 0xff;
 674
 675                         laddr = ntohl(so->so_faddr.s_addr);
 676
 677                         n1 = ((laddr >> 24) & 0xff);
 678                         n2 = ((laddr >> 16) & 0xff);
 679                         n3 = ((laddr >> 8)  & 0xff);
 680                         n4 =  (laddr & 0xff);
 681
 682                         m->m_len = bptr - m->m_data; /* Adjust length */
 683                         m->m_len += snprintf(bptr, m->m_hdr.mh_size - m->m_len,
 684                                              "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
 685                                              n1, n2, n3, n4, n5, n6, x==7?buff:"");
 686
 687                         return 1;
 688                 }
 689
 690                 return 1;
 691
 692          case EMU_KSH:
 693                 /*
 694                  * The kshell (Kerberos rsh) and shell services both pass
 695                  * a local port port number to carry signals to the server
 696                  * and stderr to the client.  It is passed at the beginning
 697                  * of the connection as a NUL-terminated decimal ASCII string.
 698                  */
 699                 so->so_emu = 0;
 700                 for (lport = 0, i = 0; i < m->m_len-1; ++i) {
 701                         if (m->m_data[i] < '0' || m->m_data[i] > '9')
 702                                 return 1;       /* invalid number */
 703                         lport *= 10;
 704                         lport += m->m_data[i] - '0';
 705                 }
 706                 if (m->m_data[m->m_len-1] == '\0' && lport != 0 &&
 707                     (so = tcp_listen(slirp, INADDR_ANY, 0, so->so_laddr.s_addr,
 708                                      htons(lport), SS_FACCEPTONCE)) != NULL)
 709                     m->m_len = snprintf(m->m_data, m->m_hdr.mh_size, "%d",
 710                                         ntohs(so->so_fport)) + 1;
 711                 return 1;
 712
 713          case EMU_IRC:
 714                 /*
 715                  * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
 716                  */
 717                 *(m->m_data+m->m_len) = 0; /* NULL terminate the string for strstr */
 718                 if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
 719                          return 1;
 720
 721                 /* The %256s is for the broken mIRC */
 722                 if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
 723                         if ((so = tcp_listen(slirp, INADDR_ANY, 0,
 724                                              htonl(laddr), htons(lport),
 725                                              SS_FACCEPTONCE)) == NULL) {
 726                                 return 1;
 727                         }
 728                         m->m_len = bptr - m->m_data; /* Adjust length */
 729                         m->m_len += snprintf(bptr, m->m_hdr.mh_size,
 730                                              "DCC CHAT chat %lu %u%c\n",
 731                                              (unsigned long)ntohl(so->so_faddr.s_addr),
 732                                              ntohs(so->so_fport), 1);
 733                 } else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
 734                         if ((so = tcp_listen(slirp, INADDR_ANY, 0,
 735                                              htonl(laddr), htons(lport),
 736                                              SS_FACCEPTONCE)) == NULL) {
 737                                 return 1;
 738                         }
 739                         m->m_len = bptr - m->m_data; /* Adjust length */
 740                         m->m_len += snprintf(bptr, m->m_hdr.mh_size,
 741                                              "DCC SEND %s %lu %u %u%c\n", buff,
 742                                              (unsigned long)ntohl(so->so_faddr.s_addr),
 743                                              ntohs(so->so_fport), n1, 1);
 744                 } else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport, &n1) == 4) {
 745                         if ((so = tcp_listen(slirp, INADDR_ANY, 0,
 746                                              htonl(laddr), htons(lport),
 747                                              SS_FACCEPTONCE)) == NULL) {
 748                                 return 1;
 749                         }
 750                         m->m_len = bptr - m->m_data; /* Adjust length */
 751                         m->m_len += snprintf(bptr, m->m_hdr.mh_size,
 752                                              "DCC MOVE %s %lu %u %u%c\n", buff,
 753                                              (unsigned long)ntohl(so->so_faddr.s_addr),
 754                                              ntohs(so->so_fport), n1, 1);
 755                 }
 756                 return 1;
 757
 758          case EMU_REALAUDIO:
 759                 /*
 760                  * RealAudio emulation - JP. We must try to parse the incoming
 761                  * data and try to find the two characters that contain the
 762                  * port number. Then we redirect an udp port and replace the
 763                  * number with the real port we got.
 764                  *
 765                  * The 1.0 beta versions of the player are not supported
 766                  * any more.
 767                  *
 768                  * A typical packet for player version 1.0 (release version):
 769                  *
 770                  * 0000:50 4E 41 00 05
 771                  * 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 ........g.l.c..P
 772                  * 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
 773                  * 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
 774                  * 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
 775                  *
 776                  * Now the port number 0x1BD7 is found at offset 0x04 of the
 777                  * Now the port number 0x1BD7 is found at offset 0x04 of the
 778                  * second packet. This time we received five bytes first and
 779                  * then the rest. You never know how many bytes you get.
 780                  *
 781                  * A typical packet for player version 2.0 (beta):
 782                  *
 783                  * 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA.............
 784                  * 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux.c..Win2.0.0
 785                  * 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
 786                  * 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
 787                  * 0040:65 2E 72 61 79 53 00 00 06 36 42                e.rayS...6B
 788                  *
 789                  * Port number 0x1BC1 is found at offset 0x0d.
 790                  *
 791                  * This is just a horrible switch statement. Variable ra tells
 792                  * us where we're going.
 793                  */
 794
 795                 bptr = m->m_data;
 796                 while (bptr < m->m_data + m->m_len) {
 797                         u_short p;
 798                         static int ra = 0;
 799                         char ra_tbl[4];
 800
 801                         ra_tbl[0] = 0x50;
 802                         ra_tbl[1] = 0x4e;
 803                         ra_tbl[2] = 0x41;
 804                         ra_tbl[3] = 0;
 805
 806                         switch (ra) {
 807                          case 0:
 808                          case 2:
 809                          case 3:
 810                                 if (*bptr++ != ra_tbl[ra]) {
 811                                         ra = 0;
 812                                         continue;
 813                                 }
 814                                 break;
 815
 816                          case 1:
 817                                 /*
 818                                  * We may get 0x50 several times, ignore them
 819                                  */
 820                                 if (*bptr == 0x50) {
 821                                         ra = 1;
 822                                         bptr++;
 823                                         continue;
 824                                 } else if (*bptr++ != ra_tbl[ra]) {
 825                                         ra = 0;
 826                                         continue;
 827                                 }
 828                                 break;
 829
 830                          case 4:
 831                                 /*
 832                                  * skip version number
 833                                  */
 834                                 bptr++;
 835                                 break;
 836
 837                          case 5:
 838                                 /*
 839                                  * The difference between versions 1.0 and
 840                                  * 2.0 is here. For future versions of
 841                                  * the player this may need to be modified.
 842                                  */
 843                                 if (*(bptr + 1) == 0x02)
 844                                    bptr += 8;
 845                                 else
 846                                    bptr += 4;
 847                                 break;
 848
 849                          case 6:
 850                                 /* This is the field containing the port
 851                                  * number that RA-player is listening to.
 852                                  */
 853                                 lport = (((u_char*)bptr)[0] << 8)
 854                                 + ((u_char *)bptr)[1];
 855                                 if (lport < 6970)
 856                                    lport += 256;   /* don't know why */
 857                                 if (lport < 6970 || lport > 7170)
 858                                    return 1;       /* failed */
 859
 860                                 /* try to get udp port between 6970 - 7170 */
 861                                 for (p = 6970; p < 7071; p++) {
 862                                         if (udp_listen(slirp, INADDR_ANY,
 863                                                        htons(p),
 864                                                        so->so_laddr.s_addr,
 865                                                        htons(lport),
 866                                                        SS_FACCEPTONCE)) {
 867                                                 break;
 868                                         }
 869                                 }
 870                                 if (p == 7071)
 871                                    p = 0;
 872                                 *(u_char *)bptr++ = (p >> 8) & 0xff;
 873                                 *(u_char *)bptr = p & 0xff;
 874                                 ra = 0;
 875                                 return 1;   /* port redirected, we're done */
 876                                 break;
 877
 878                          default:
 879                                 ra = 0;
 880                         }
 881                         ra++;
 882                 }
 883                 return 1;
 884
 885          default:
 886                 /* Ooops, not emulated, won't call tcp_emu again */
 887                 so->so_emu = 0;
 888                 return 1;
 889         }
 890 }
 891
 892 /*
 893  * Do misc. config of SLiRP while its running.
 894  * Return 0 if this connections is to be closed, 1 otherwise,
 895  * return 2 if this is a command-line connection
 896  */
 897 int tcp_ctl(struct socket *so)
 898 {
 899     Slirp *slirp = so->slirp;
 900     struct sbuf *sb = &so->so_snd;
 901     struct ex_list *ex_ptr;
 902     int do_pty;
 903
 904     DEBUG_CALL("tcp_ctl");
 905     DEBUG_ARG("so = %lx", (long )so);
 906
 907     if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
 908         /* Check if it's pty_exec */
 909         for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
 910             if (ex_ptr->ex_fport == so->so_fport &&
 911                 so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
 912                 if (ex_ptr->ex_pty == 3) {
 913                     so->s = -1;
 914                     so->extra = (void *)ex_ptr->ex_exec;
 915                     return 1;
 916                 }
 917                 do_pty = ex_ptr->ex_pty;
 918                 DEBUG_MISC((dfd, " executing %s\n", ex_ptr->ex_exec));
 919                 return fork_exec(so, ex_ptr->ex_exec, do_pty);
 920             }
 921         }
 922     }
 923     sb->sb_cc =
 924         snprintf(sb->sb_wptr, sb->sb_datalen - (sb->sb_wptr - sb->sb_data),
 925                  "Error: No application configured.\r\n");
 926     sb->sb_wptr += sb->sb_cc;
 927     return 0;
 928 }