slirp/slirp.c

   1 #include "slirp.h"
   2
   3 /* host address */
   4 struct in_addr our_addr;
   5 /* host dns address */
   6 struct in_addr dns_addr;
   7 /* host loopback address */
   8 struct in_addr loopback_addr;
   9
  10 /* address for slirp virtual addresses */
  11 struct in_addr special_addr;
  12
  13 const uint8_t special_ethaddr[6] = {
  14     0x52, 0x54, 0x00, 0x12, 0x35, 0x00
  15 };
  16
  17 uint8_t client_ethaddr[6];
  18
  19 int do_slowtimo;
  20 int link_up;
  21 struct timeval tt;
  22 FILE *lfd;
  23 struct ex_list *exec_list;
  24
  25 /* XXX: suppress those select globals */
  26 fd_set *global_readfds, *global_writefds, *global_xfds;
  27
  28 const char slirp_hostname[33];
  29
  30 #ifdef _WIN32
  31
  32 static int get_dns_addr(struct in_addr *pdns_addr)
  33 {
  34     FIXED_INFO *FixedInfo=NULL;
  35     ULONG    BufLen;
  36     DWORD    ret;
  37     IP_ADDR_STRING *pIPAddr;
  38     struct in_addr tmp_addr;
  39
  40     FixedInfo = (FIXED_INFO *)GlobalAlloc(GPTR, sizeof(FIXED_INFO));
  41     BufLen = sizeof(FIXED_INFO);
  42
  43     if (ERROR_BUFFER_OVERFLOW == GetNetworkParams(FixedInfo, &BufLen)) {
  44         if (FixedInfo) {
  45             GlobalFree(FixedInfo);
  46             FixedInfo = NULL;
  47         }
  48         FixedInfo = GlobalAlloc(GPTR, BufLen);
  49     }
  50
  51     if ((ret = GetNetworkParams(FixedInfo, &BufLen)) != ERROR_SUCCESS) {
  52         printf("GetNetworkParams failed. ret = %08x\n", (u_int)ret );
  53         if (FixedInfo) {
  54             GlobalFree(FixedInfo);
  55             FixedInfo = NULL;
  56         }
  57         return -1;
  58     }
  59
  60     pIPAddr = &(FixedInfo->DnsServerList);
  61     inet_aton(pIPAddr->IpAddress.String, &tmp_addr);
  62     *pdns_addr = tmp_addr;
  63 #if 0
  64     printf( "DNS Servers:\n" );
  65     printf( "DNS Addr:%s\n", pIPAddr->IpAddress.String );
  66
  67     pIPAddr = FixedInfo -> DnsServerList.Next;
  68     while ( pIPAddr ) {
  69             printf( "DNS Addr:%s\n", pIPAddr ->IpAddress.String );
  70             pIPAddr = pIPAddr ->Next;
  71     }
  72 #endif
  73     if (FixedInfo) {
  74         GlobalFree(FixedInfo);
  75         FixedInfo = NULL;
  76     }
  77     return 0;
  78 }
  79
  80 #else
  81
  82 static int get_dns_addr(struct in_addr *pdns_addr)
  83 {
  84     char buff[512];
  85     char buff2[256];
  86     FILE *f;
  87     int found = 0;
  88     struct in_addr tmp_addr;
  89
  90     f = fopen("/etc/resolv.conf", "r");
  91     if (!f)
  92         return -1;
  93
  94     lprint("IP address of your DNS(s): ");
  95     while (fgets(buff, 512, f) != NULL) {
  96         if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) {
  97             if (!inet_aton(buff2, &tmp_addr))
  98                 continue;
  99             if (tmp_addr.s_addr == loopback_addr.s_addr)
 100                 tmp_addr = our_addr;
 101             /* If it's the first one, set it to dns_addr */
 102             if (!found)
 103                 *pdns_addr = tmp_addr;
 104             else
 105                 lprint(", ");
 106             if (++found > 3) {
 107                 lprint("(more)");
 108                 break;
 109             } else
 110                 lprint("%s", inet_ntoa(tmp_addr));
 111         }
 112     }
 113     fclose(f);
 114     if (!found)
 115         return -1;
 116     return 0;
 117 }
 118
 119 #endif
 120
 121 #ifdef _WIN32
 122 void slirp_cleanup(void)
 123 {
 124     WSACleanup();
 125 }
 126 #endif
 127
 128 void slirp_init(void)
 129 {
 130     //    debug_init("/tmp/slirp.log", DEBUG_DEFAULT);
 131
 132 #ifdef _WIN32
 133     {
 134         WSADATA Data;
 135         WSAStartup(MAKEWORD(2,0), &Data);
 136         atexit(slirp_cleanup);
 137     }
 138 #endif
 139
 140     link_up = 1;
 141
 142     if_init();
 143     ip_init();
 144
 145     /* Initialise mbufs *after* setting the MTU */
 146     m_init();
 147
 148     /* set default addresses */
 149     getouraddr();
 150     inet_aton("127.0.0.1", &loopback_addr);
 151
 152     if (get_dns_addr(&dns_addr) < 0) {
 153         dns_addr = loopback_addr;
 154         fprintf (stderr, "Warning: No DNS servers found\n");
 155     }
 156
 157     inet_aton(CTL_SPECIAL, &special_addr);
 158 }
 159
 160 #define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
 161 #define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
 162 #define UPD_NFDS(x) if (nfds < (x)) nfds = (x)
 163
 164 /*
 165  * curtime kept to an accuracy of 1ms
 166  */
 167 #ifdef _WIN32
 168 static void updtime(void)
 169 {
 170     struct _timeb tb;
 171
 172     _ftime(&tb);
 173     curtime = (u_int)tb.time * (u_int)1000;
 174     curtime += (u_int)tb.millitm;
 175 }
 176 #else
 177 static void updtime(void)
 178 {
 179         gettimeofday(&tt, 0);
 180
 181         curtime = (u_int)tt.tv_sec * (u_int)1000;
 182         curtime += (u_int)tt.tv_usec / (u_int)1000;
 183
 184         if ((tt.tv_usec % 1000) >= 500)
 185            curtime++;
 186 }
 187 #endif
 188
 189 void slirp_select_fill(int *pnfds,
 190                        fd_set *readfds, fd_set *writefds, fd_set *xfds)
 191 {
 192     struct socket *so, *so_next;
 193     struct timeval timeout;
 194     int nfds;
 195     int tmp_time;
 196
 197     /* fail safe */
 198     global_readfds = NULL;
 199     global_writefds = NULL;
 200     global_xfds = NULL;
 201
 202     nfds = *pnfds;
 203         /*
 204          * First, TCP sockets
 205          */
 206         do_slowtimo = 0;
 207         if (link_up) {
 208                 /*
 209                  * *_slowtimo needs calling if there are IP fragments
 210                  * in the fragment queue, or there are TCP connections active
 211                  */
 212                 do_slowtimo = ((tcb.so_next != &tcb) ||
 213                                ((struct ipasfrag *)&ipq != (struct ipasfrag *)ipq.next));
 214
 215                 for (so = tcb.so_next; so != &tcb; so = so_next) {
 216                         so_next = so->so_next;
 217
 218                         /*
 219                          * See if we need a tcp_fasttimo
 220                          */
 221                         if (time_fasttimo == 0 && so->so_tcpcb->t_flags & TF_DELACK)
 222                            time_fasttimo = curtime; /* Flag when we want a fasttimo */
 223
 224                         /*
 225                          * NOFDREF can include still connecting to local-host,
 226                          * newly socreated() sockets etc. Don't want to select these.
 227                          */
 228                         if (so->so_state & SS_NOFDREF || so->s == -1)
 229                            continue;
 230
 231                         /*
 232                          * Set for reading sockets which are accepting
 233                          */
 234                         if (so->so_state & SS_FACCEPTCONN) {
 235                                 FD_SET(so->s, readfds);
 236                                 UPD_NFDS(so->s);
 237                                 continue;
 238                         }
 239
 240                         /*
 241                          * Set for writing sockets which are connecting
 242                          */
 243                         if (so->so_state & SS_ISFCONNECTING) {
 244                                 FD_SET(so->s, writefds);
 245                                 UPD_NFDS(so->s);
 246                                 continue;
 247                         }
 248
 249                         /*
 250                          * Set for writing if we are connected, can send more, and
 251                          * we have something to send
 252                          */
 253                         if (CONN_CANFSEND(so) && so->so_rcv.sb_cc) {
 254                                 FD_SET(so->s, writefds);
 255                                 UPD_NFDS(so->s);
 256                         }
 257
 258                         /*
 259                          * Set for reading (and urgent data) if we are connected, can
 260                          * receive more, and we have room for it XXX /2 ?
 261                          */
 262                         if (CONN_CANFRCV(so) && (so->so_snd.sb_cc < (so->so_snd.sb_datalen/2))) {
 263                                 FD_SET(so->s, readfds);
 264                                 FD_SET(so->s, xfds);
 265                                 UPD_NFDS(so->s);
 266                         }
 267                 }
 268
 269                 /*
 270                  * UDP sockets
 271                  */
 272                 for (so = udb.so_next; so != &udb; so = so_next) {
 273                         so_next = so->so_next;
 274
 275                         /*
 276                          * See if it's timed out
 277                          */
 278                         if (so->so_expire) {
 279                                 if (so->so_expire <= curtime) {
 280                                         udp_detach(so);
 281                                         continue;
 282                                 } else
 283                                         do_slowtimo = 1; /* Let socket expire */
 284                         }
 285
 286                         /*
 287                          * When UDP packets are received from over the
 288                          * link, they're sendto()'d straight away, so
 289                          * no need for setting for writing
 290                          * Limit the number of packets queued by this session
 291                          * to 4.  Note that even though we try and limit this
 292                          * to 4 packets, the session could have more queued
 293                          * if the packets needed to be fragmented
 294                          * (XXX <= 4 ?)
 295                          */
 296                         if ((so->so_state & SS_ISFCONNECTED) && so->so_queued <= 4) {
 297                                 FD_SET(so->s, readfds);
 298                                 UPD_NFDS(so->s);
 299                         }
 300                 }
 301         }
 302
 303         /*
 304          * Setup timeout to use minimum CPU usage, especially when idle
 305          */
 306
 307         /*
 308          * First, see the timeout needed by *timo
 309          */
 310         timeout.tv_sec = 0;
 311         timeout.tv_usec = -1;
 312         /*
 313          * If a slowtimo is needed, set timeout to 500ms from the last
 314          * slow timeout. If a fast timeout is needed, set timeout within
 315          * 200ms of when it was requested.
 316          */
 317         if (do_slowtimo) {
 318                 /* XXX + 10000 because some select()'s aren't that accurate */
 319                 timeout.tv_usec = ((500 - (curtime - last_slowtimo)) * 1000) + 10000;
 320                 if (timeout.tv_usec < 0)
 321                    timeout.tv_usec = 0;
 322                 else if (timeout.tv_usec > 510000)
 323                    timeout.tv_usec = 510000;
 324
 325                 /* Can only fasttimo if we also slowtimo */
 326                 if (time_fasttimo) {
 327                         tmp_time = (200 - (curtime - time_fasttimo)) * 1000;
 328                         if (tmp_time < 0)
 329                            tmp_time = 0;
 330
 331                         /* Choose the smallest of the 2 */
 332                         if (tmp_time < timeout.tv_usec)
 333                            timeout.tv_usec = (u_int)tmp_time;
 334                 }
 335         }
 336         *pnfds = nfds;
 337 }
 338
 339 void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds)
 340 {
 341     struct socket *so, *so_next;
 342     int ret;
 343
 344     global_readfds = readfds;
 345     global_writefds = writefds;
 346     global_xfds = xfds;
 347
 348         /* Update time */
 349         updtime();
 350
 351         /*
 352          * See if anything has timed out
 353          */
 354         if (link_up) {
 355                 if (time_fasttimo && ((curtime - time_fasttimo) >= 2)) {
 356                         tcp_fasttimo();
 357                         time_fasttimo = 0;
 358                 }
 359                 if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {
 360                         ip_slowtimo();
 361                         tcp_slowtimo();
 362                         last_slowtimo = curtime;
 363                 }
 364         }
 365
 366         /*
 367          * Check sockets
 368          */
 369         if (link_up) {
 370                 /*
 371                  * Check TCP sockets
 372                  */
 373                 for (so = tcb.so_next; so != &tcb; so = so_next) {
 374                         so_next = so->so_next;
 375
 376                         /*
 377                          * FD_ISSET is meaningless on these sockets
 378                          * (and they can crash the program)
 379                          */
 380                         if (so->so_state & SS_NOFDREF || so->s == -1)
 381                            continue;
 382
 383                         /*
 384                          * Check for URG data
 385                          * This will soread as well, so no need to
 386                          * test for readfds below if this succeeds
 387                          */
 388                         if (FD_ISSET(so->s, xfds))
 389                            sorecvoob(so);
 390                         /*
 391                          * Check sockets for reading
 392                          */
 393                         else if (FD_ISSET(so->s, readfds)) {
 394                                 /*
 395                                  * Check for incoming connections
 396                                  */
 397                                 if (so->so_state & SS_FACCEPTCONN) {
 398                                         tcp_connect(so);
 399                                         continue;
 400                                 } /* else */
 401                                 ret = soread(so);
 402
 403                                 /* Output it if we read something */
 404                                 if (ret > 0)
 405                                    tcp_output(sototcpcb(so));
 406                         }
 407
 408                         /*
 409                          * Check sockets for writing
 410                          */
 411                         if (FD_ISSET(so->s, writefds)) {
 412                           /*
 413                            * Check for non-blocking, still-connecting sockets
 414                            */
 415                           if (so->so_state & SS_ISFCONNECTING) {
 416                             /* Connected */
 417                             so->so_state &= ~SS_ISFCONNECTING;
 418
 419                             ret = send(so->s, &ret, 0, 0);
 420                             if (ret < 0) {
 421                               /* XXXXX Must fix, zero bytes is a NOP */
 422                               if (errno == EAGAIN || errno == EWOULDBLOCK ||
 423                                   errno == EINPROGRESS || errno == ENOTCONN)
 424                                 continue;
 425
 426                               /* else failed */
 427                               so->so_state = SS_NOFDREF;
 428                             }
 429                             /* else so->so_state &= ~SS_ISFCONNECTING; */
 430
 431                             /*
 432                              * Continue tcp_input
 433                              */
 434                             tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
 435                             /* continue; */
 436                           } else
 437                             ret = sowrite(so);
 438                           /*
 439                            * XXXXX If we wrote something (a lot), there
 440                            * could be a need for a window update.
 441                            * In the worst case, the remote will send
 442                            * a window probe to get things going again
 443                            */
 444                         }
 445
 446                         /*
 447                          * Probe a still-connecting, non-blocking socket
 448                          * to check if it's still alive
 449                          */
 450 #ifdef PROBE_CONN
 451                         if (so->so_state & SS_ISFCONNECTING) {
 452                           ret = recv(so->s, (char *)&ret, 0,0);
 453
 454                           if (ret < 0) {
 455                             /* XXX */
 456                             if (errno == EAGAIN || errno == EWOULDBLOCK ||
 457                                 errno == EINPROGRESS || errno == ENOTCONN)
 458                               continue; /* Still connecting, continue */
 459
 460                             /* else failed */
 461                             so->so_state = SS_NOFDREF;
 462
 463                             /* tcp_input will take care of it */
 464                           } else {
 465                             ret = send(so->s, &ret, 0,0);
 466                             if (ret < 0) {
 467                               /* XXX */
 468                               if (errno == EAGAIN || errno == EWOULDBLOCK ||
 469                                   errno == EINPROGRESS || errno == ENOTCONN)
 470                                 continue;
 471                               /* else failed */
 472                               so->so_state = SS_NOFDREF;
 473                             } else
 474                               so->so_state &= ~SS_ISFCONNECTING;
 475
 476                           }
 477                           tcp_input((struct mbuf *)NULL, sizeof(struct ip),so);
 478                         } /* SS_ISFCONNECTING */
 479 #endif
 480                 }
 481
 482                 /*
 483                  * Now UDP sockets.
 484                  * Incoming packets are sent straight away, they're not buffered.
 485                  * Incoming UDP data isn't buffered either.
 486                  */
 487                 for (so = udb.so_next; so != &udb; so = so_next) {
 488                         so_next = so->so_next;
 489
 490                         if (so->s != -1 && FD_ISSET(so->s, readfds)) {
 491                             sorecvfrom(so);
 492                         }
 493                 }
 494         }
 495
 496         /*
 497          * See if we can start outputting
 498          */
 499         if (if_queued && link_up)
 500            if_start();
 501
 502         /* clear global file descriptor sets.
 503          * these reside on the stack in vl.c
 504          * so they're unusable if we're not in
 505          * slirp_select_fill or slirp_select_poll.
 506          */
 507          global_readfds = NULL;
 508          global_writefds = NULL;
 509          global_xfds = NULL;
 510 }
 511
 512 #define ETH_ALEN 6
 513 #define ETH_HLEN 14
 514
 515 #define ETH_P_IP        0x0800          /* Internet Protocol packet     */
 516 #define ETH_P_ARP       0x0806          /* Address Resolution packet    */
 517
 518 #define ARPOP_REQUEST   1               /* ARP request                  */
 519 #define ARPOP_REPLY     2               /* ARP reply                    */
 520
 521 struct ethhdr
 522 {
 523         unsigned char   h_dest[ETH_ALEN];       /* destination eth addr */
 524         unsigned char   h_source[ETH_ALEN];     /* source ether addr    */
 525         unsigned short  h_proto;                /* packet type ID field */
 526 };
 527
 528 struct arphdr
 529 {
 530         unsigned short  ar_hrd;         /* format of hardware address   */
 531         unsigned short  ar_pro;         /* format of protocol address   */
 532         unsigned char   ar_hln;         /* length of hardware address   */
 533         unsigned char   ar_pln;         /* length of protocol address   */
 534         unsigned short  ar_op;          /* ARP opcode (command)         */
 535
 536          /*
 537           *      Ethernet looks like this : This bit is variable sized however...
 538           */
 539         unsigned char           ar_sha[ETH_ALEN];       /* sender hardware address      */
 540         unsigned char           ar_sip[4];              /* sender IP address            */
 541         unsigned char           ar_tha[ETH_ALEN];       /* target hardware address      */
 542         unsigned char           ar_tip[4];              /* target IP address            */
 543 };
 544
 545 void arp_input(const uint8_t *pkt, int pkt_len)
 546 {
 547     struct ethhdr *eh = (struct ethhdr *)pkt;
 548     struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN);
 549     uint8_t arp_reply[ETH_HLEN + sizeof(struct arphdr)];
 550     struct ethhdr *reh = (struct ethhdr *)arp_reply;
 551     struct arphdr *rah = (struct arphdr *)(arp_reply + ETH_HLEN);
 552     int ar_op;
 553     struct ex_list *ex_ptr;
 554
 555     ar_op = ntohs(ah->ar_op);
 556     switch(ar_op) {
 557     case ARPOP_REQUEST:
 558         if (!memcmp(ah->ar_tip, &special_addr, 3)) {
 559             if (ah->ar_tip[3] == CTL_DNS || ah->ar_tip[3] == CTL_ALIAS)
 560                 goto arp_ok;
 561             for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
 562                 if (ex_ptr->ex_addr == ah->ar_tip[3])
 563                     goto arp_ok;
 564             }
 565             return;
 566         arp_ok:
 567             /* XXX: make an ARP request to have the client address */
 568             memcpy(client_ethaddr, eh->h_source, ETH_ALEN);
 569
 570             /* ARP request for alias/dns mac address */
 571             memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN);
 572             memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 1);
 573             reh->h_source[5] = ah->ar_tip[3];
 574             reh->h_proto = htons(ETH_P_ARP);
 575
 576             rah->ar_hrd = htons(1);
 577             rah->ar_pro = htons(ETH_P_IP);
 578             rah->ar_hln = ETH_ALEN;
 579             rah->ar_pln = 4;
 580             rah->ar_op = htons(ARPOP_REPLY);
 581             memcpy(rah->ar_sha, reh->h_source, ETH_ALEN);
 582             memcpy(rah->ar_sip, ah->ar_tip, 4);
 583             memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);
 584             memcpy(rah->ar_tip, ah->ar_sip, 4);
 585             slirp_output(arp_reply, sizeof(arp_reply));
 586         }
 587         break;
 588     default:
 589         break;
 590     }
 591 }
 592
 593 void slirp_input(const uint8_t *pkt, int pkt_len)
 594 {
 595     struct mbuf *m;
 596     int proto;
 597
 598     if (pkt_len < ETH_HLEN)
 599         return;
 600
 601     proto = ntohs(*(uint16_t *)(pkt + 12));
 602     switch(proto) {
 603     case ETH_P_ARP:
 604         arp_input(pkt, pkt_len);
 605         break;
 606     case ETH_P_IP:
 607         m = m_get();
 608         if (!m)
 609             return;
 610         m->m_len = pkt_len;
 611         memcpy(m->m_data, pkt, pkt_len);
 612
 613         m->m_data += ETH_HLEN;
 614         m->m_len -= ETH_HLEN;
 615
 616         ip_input(m);
 617         break;
 618     default:
 619         break;
 620     }
 621 }
 622
 623 /* output the IP packet to the ethernet device */
 624 void if_encap(const uint8_t *ip_data, int ip_data_len)
 625 {
 626     uint8_t buf[1600];
 627     struct ethhdr *eh = (struct ethhdr *)buf;
 628
 629     if (ip_data_len + ETH_HLEN > sizeof(buf))
 630         return;
 631
 632     memcpy(eh->h_dest, client_ethaddr, ETH_ALEN);
 633     memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1);
 634     /* XXX: not correct */
 635     eh->h_source[5] = CTL_ALIAS;
 636     eh->h_proto = htons(ETH_P_IP);
 637     memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len);
 638     slirp_output(buf, ip_data_len + ETH_HLEN);
 639 }
 640
 641 int slirp_redir(int is_udp, int host_port,
 642                 struct in_addr guest_addr, int guest_port)
 643 {
 644     if (is_udp) {
 645         if (!udp_listen(htons(host_port), guest_addr.s_addr,
 646                         htons(guest_port), 0))
 647             return -1;
 648     } else {
 649         if (!solisten(htons(host_port), guest_addr.s_addr,
 650                       htons(guest_port), 0))
 651             return -1;
 652     }
 653     return 0;
 654 }
 655
 656 int slirp_add_exec(int do_pty, const char *args, int addr_low_byte,
 657                   int guest_port)
 658 {
 659     return add_exec(&exec_list, do_pty, (char *)args,
 660                     addr_low_byte, htons(guest_port));
 661 }