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