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 /* virtual address alias for host */
  13 struct in_addr alias_addr;
  14
  15 const uint8_t special_ethaddr[6] = {
  16     0x52, 0x54, 0x00, 0x12, 0x35, 0x00
  17 };
  18
  19 uint8_t client_ethaddr[6];
  20
  21 int do_slowtimo;
  22 int link_up;
  23 struct timeval tt;
  24 FILE *lfd;
  25 struct ex_list *exec_list;
  26
  27 /* XXX: suppress those select globals */
  28 fd_set *global_readfds, *global_writefds, *global_xfds;
  29
  30 char slirp_hostname[33];
  31
  32 #ifdef _WIN32
  33
  34 static int get_dns_addr(struct in_addr *pdns_addr)
  35 {
  36     FIXED_INFO *FixedInfo=NULL;
  37     ULONG    BufLen;
  38     DWORD    ret;
  39     IP_ADDR_STRING *pIPAddr;
  40     struct in_addr tmp_addr;
  41
  42     FixedInfo = (FIXED_INFO *)GlobalAlloc(GPTR, sizeof(FIXED_INFO));
  43     BufLen = sizeof(FIXED_INFO);
  44
  45     if (ERROR_BUFFER_OVERFLOW == GetNetworkParams(FixedInfo, &BufLen)) {
  46         if (FixedInfo) {
  47             GlobalFree(FixedInfo);
  48             FixedInfo = NULL;
  49         }
  50         FixedInfo = GlobalAlloc(GPTR, BufLen);
  51     }
  52
  53     if ((ret = GetNetworkParams(FixedInfo, &BufLen)) != ERROR_SUCCESS) {
  54         printf("GetNetworkParams failed. ret = %08x\n", (u_int)ret );
  55         if (FixedInfo) {
  56             GlobalFree(FixedInfo);
  57             FixedInfo = NULL;
  58         }
  59         return -1;
  60     }
  61
  62     pIPAddr = &(FixedInfo->DnsServerList);
  63     inet_aton(pIPAddr->IpAddress.String, &tmp_addr);
  64     *pdns_addr = tmp_addr;
  65 #if 0
  66     printf( "DNS Servers:\n" );
  67     printf( "DNS Addr:%s\n", pIPAddr->IpAddress.String );
  68
  69     pIPAddr = FixedInfo -> DnsServerList.Next;
  70     while ( pIPAddr ) {
  71             printf( "DNS Addr:%s\n", pIPAddr ->IpAddress.String );
  72             pIPAddr = pIPAddr ->Next;
  73     }
  74 #endif
  75     if (FixedInfo) {
  76         GlobalFree(FixedInfo);
  77         FixedInfo = NULL;
  78     }
  79     return 0;
  80 }
  81
  82 #else
  83
  84 static int get_dns_addr(struct in_addr *pdns_addr)
  85 {
  86     char buff[512];
  87     char buff2[256];
  88     FILE *f;
  89     int found = 0;
  90     struct in_addr tmp_addr;
  91
  92     f = fopen("/etc/resolv.conf", "r");
  93     if (!f)
  94         return -1;
  95
  96     lprint("IP address of your DNS(s): ");
  97     while (fgets(buff, 512, f) != NULL) {
  98         if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) {
  99             if (!inet_aton(buff2, &tmp_addr))
 100                 continue;
 101             if (tmp_addr.s_addr == loopback_addr.s_addr)
 102                 tmp_addr = our_addr;
 103             /* If it's the first one, set it to dns_addr */
 104             if (!found)
 105                 *pdns_addr = tmp_addr;
 106             else
 107                 lprint(", ");
 108             if (++found > 3) {
 109                 lprint("(more)");
 110                 break;
 111             } else
 112                 lprint("%s", inet_ntoa(tmp_addr));
 113         }
 114     }
 115     fclose(f);
 116     if (!found)
 117         return -1;
 118     return 0;
 119 }
 120
 121 #endif
 122
 123 #ifdef _WIN32
 124 void slirp_cleanup(void)
 125 {
 126     WSACleanup();
 127 }
 128 #endif
 129
 130 void slirp_init(void)
 131 {
 132     //    debug_init("/tmp/slirp.log", DEBUG_DEFAULT);
 133
 134 #ifdef _WIN32
 135     {
 136         WSADATA Data;
 137         WSAStartup(MAKEWORD(2,0), &Data);
 138         atexit(slirp_cleanup);
 139     }
 140 #endif
 141
 142     link_up = 1;
 143
 144     if_init();
 145     ip_init();
 146
 147     /* Initialise mbufs *after* setting the MTU */
 148     m_init();
 149
 150     /* set default addresses */
 151     inet_aton("127.0.0.1", &loopback_addr);
 152
 153     if (get_dns_addr(&dns_addr) < 0) {
 154         dns_addr = loopback_addr;
 155         fprintf (stderr, "Warning: No DNS servers found\n");
 156     }
 157
 158     inet_aton(CTL_SPECIAL, &special_addr);
 159     alias_addr.s_addr = special_addr.s_addr | htonl(CTL_ALIAS);
 160     getouraddr();
 161 }
 162
 163 #define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
 164 #define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
 165 #define UPD_NFDS(x) if (nfds < (x)) nfds = (x)
 166
 167 /*
 168  * curtime kept to an accuracy of 1ms
 169  */
 170 #ifdef _WIN32
 171 static void updtime(void)
 172 {
 173     struct _timeb tb;
 174
 175     _ftime(&tb);
 176     curtime = (u_int)tb.time * (u_int)1000;
 177     curtime += (u_int)tb.millitm;
 178 }
 179 #else
 180 static void updtime(void)
 181 {
 182         gettimeofday(&tt, 0);
 183
 184         curtime = (u_int)tt.tv_sec * (u_int)1000;
 185         curtime += (u_int)tt.tv_usec / (u_int)1000;
 186
 187         if ((tt.tv_usec % 1000) >= 500)
 188            curtime++;
 189 }
 190 #endif
 191
 192 void slirp_select_fill(int *pnfds,
 193                        fd_set *readfds, fd_set *writefds, fd_set *xfds)
 194 {
 195     struct socket *so, *so_next;
 196     struct timeval timeout;
 197     int nfds;
 198     int tmp_time;
 199
 200     /* fail safe */
 201     global_readfds = NULL;
 202     global_writefds = NULL;
 203     global_xfds = NULL;
 204
 205     nfds = *pnfds;
 206         /*
 207          * First, TCP sockets
 208          */
 209         do_slowtimo = 0;
 210         if (link_up) {
 211                 /*
 212                  * *_slowtimo needs calling if there are IP fragments
 213                  * in the fragment queue, or there are TCP connections active
 214                  */
 215                 do_slowtimo = ((tcb.so_next != &tcb) ||
 216                                ((struct ipasfrag *)&ipq != (struct ipasfrag *)ipq.next));
 217
 218                 for (so = tcb.so_next; so != &tcb; so = so_next) {
 219                         so_next = so->so_next;
 220
 221                         /*
 222                          * See if we need a tcp_fasttimo
 223                          */
 224                         if (time_fasttimo == 0 && so->so_tcpcb->t_flags & TF_DELACK)
 225                            time_fasttimo = curtime; /* Flag when we want a fasttimo */
 226
 227                         /*
 228                          * NOFDREF can include still connecting to local-host,
 229                          * newly socreated() sockets etc. Don't want to select these.
 230                          */
 231                         if (so->so_state & SS_NOFDREF || so->s == -1)
 232                            continue;
 233
 234                         /*
 235                          * Set for reading sockets which are accepting
 236                          */
 237                         if (so->so_state & SS_FACCEPTCONN) {
 238                                 FD_SET(so->s, readfds);
 239                                 UPD_NFDS(so->s);
 240                                 continue;
 241                         }
 242
 243                         /*
 244                          * Set for writing sockets which are connecting
 245                          */
 246                         if (so->so_state & SS_ISFCONNECTING) {
 247                                 FD_SET(so->s, writefds);
 248                                 UPD_NFDS(so->s);
 249                                 continue;
 250                         }
 251
 252                         /*
 253                          * Set for writing if we are connected, can send more, and
 254                          * we have something to send
 255                          */
 256                         if (CONN_CANFSEND(so) && so->so_rcv.sb_cc) {
 257                                 FD_SET(so->s, writefds);
 258                                 UPD_NFDS(so->s);
 259                         }
 260
 261                         /*
 262                          * Set for reading (and urgent data) if we are connected, can
 263                          * receive more, and we have room for it XXX /2 ?
 264                          */
 265                         if (CONN_CANFRCV(so) && (so->so_snd.sb_cc < (so->so_snd.sb_datalen/2))) {
 266                                 FD_SET(so->s, readfds);
 267                                 FD_SET(so->s, xfds);
 268                                 UPD_NFDS(so->s);
 269                         }
 270                 }
 271
 272                 /*
 273                  * UDP sockets
 274                  */
 275                 for (so = udb.so_next; so != &udb; so = so_next) {
 276                         so_next = so->so_next;
 277
 278                         /*
 279                          * See if it's timed out
 280                          */
 281                         if (so->so_expire) {
 282                                 if (so->so_expire <= curtime) {
 283                                         udp_detach(so);
 284                                         continue;
 285                                 } else
 286                                         do_slowtimo = 1; /* Let socket expire */
 287                         }
 288
 289                         /*
 290                          * When UDP packets are received from over the
 291                          * link, they're sendto()'d straight away, so
 292                          * no need for setting for writing
 293                          * Limit the number of packets queued by this session
 294                          * to 4.  Note that even though we try and limit this
 295                          * to 4 packets, the session could have more queued
 296                          * if the packets needed to be fragmented
 297                          * (XXX <= 4 ?)
 298                          */
 299                         if ((so->so_state & SS_ISFCONNECTED) && so->so_queued <= 4) {
 300                                 FD_SET(so->s, readfds);
 301                                 UPD_NFDS(so->s);
 302                         }
 303                 }
 304         }
 305
 306         /*
 307          * Setup timeout to use minimum CPU usage, especially when idle
 308          */
 309
 310         /*
 311          * First, see the timeout needed by *timo
 312          */
 313         timeout.tv_sec = 0;
 314         timeout.tv_usec = -1;
 315         /*
 316          * If a slowtimo is needed, set timeout to 500ms from the last
 317          * slow timeout. If a fast timeout is needed, set timeout within
 318          * 200ms of when it was requested.
 319          */
 320         if (do_slowtimo) {
 321                 /* XXX + 10000 because some select()'s aren't that accurate */
 322                 timeout.tv_usec = ((500 - (curtime - last_slowtimo)) * 1000) + 10000;
 323                 if (timeout.tv_usec < 0)
 324                    timeout.tv_usec = 0;
 325                 else if (timeout.tv_usec > 510000)
 326                    timeout.tv_usec = 510000;
 327
 328                 /* Can only fasttimo if we also slowtimo */
 329                 if (time_fasttimo) {
 330                         tmp_time = (200 - (curtime - time_fasttimo)) * 1000;
 331                         if (tmp_time < 0)
 332                            tmp_time = 0;
 333
 334                         /* Choose the smallest of the 2 */
 335                         if (tmp_time < timeout.tv_usec)
 336                            timeout.tv_usec = (u_int)tmp_time;
 337                 }
 338         }
 339         *pnfds = nfds;
 340 }
 341
 342 void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds)
 343 {
 344     struct socket *so, *so_next;
 345     int ret;
 346
 347     global_readfds = readfds;
 348     global_writefds = writefds;
 349     global_xfds = xfds;
 350
 351         /* Update time */
 352         updtime();
 353
 354         /*
 355          * See if anything has timed out
 356          */
 357         if (link_up) {
 358                 if (time_fasttimo && ((curtime - time_fasttimo) >= 2)) {
 359                         tcp_fasttimo();
 360                         time_fasttimo = 0;
 361                 }
 362                 if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {
 363                         ip_slowtimo();
 364                         tcp_slowtimo();
 365                         last_slowtimo = curtime;
 366                 }
 367         }
 368
 369         /*
 370          * Check sockets
 371          */
 372         if (link_up) {
 373                 /*
 374                  * Check TCP sockets
 375                  */
 376                 for (so = tcb.so_next; so != &tcb; so = so_next) {
 377                         so_next = so->so_next;
 378
 379                         /*
 380                          * FD_ISSET is meaningless on these sockets
 381                          * (and they can crash the program)
 382                          */
 383                         if (so->so_state & SS_NOFDREF || so->s == -1)
 384                            continue;
 385
 386                         /*
 387                          * Check for URG data
 388                          * This will soread as well, so no need to
 389                          * test for readfds below if this succeeds
 390                          */
 391                         if (FD_ISSET(so->s, xfds))
 392                            sorecvoob(so);
 393                         /*
 394                          * Check sockets for reading
 395                          */
 396                         else if (FD_ISSET(so->s, readfds)) {
 397                                 /*
 398                                  * Check for incoming connections
 399                                  */
 400                                 if (so->so_state & SS_FACCEPTCONN) {
 401                                         tcp_connect(so);
 402                                         continue;
 403                                 } /* else */
 404                                 ret = soread(so);
 405
 406                                 /* Output it if we read something */
 407                                 if (ret > 0)
 408                                    tcp_output(sototcpcb(so));
 409                         }
 410
 411                         /*
 412                          * Check sockets for writing
 413                          */
 414                         if (FD_ISSET(so->s, writefds)) {
 415                           /*
 416                            * Check for non-blocking, still-connecting sockets
 417                            */
 418                           if (so->so_state & SS_ISFCONNECTING) {
 419                             /* Connected */
 420                             so->so_state &= ~SS_ISFCONNECTING;
 421
 422                             ret = send(so->s, &ret, 0, 0);
 423                             if (ret < 0) {
 424                               /* XXXXX Must fix, zero bytes is a NOP */
 425                               if (errno == EAGAIN || errno == EWOULDBLOCK ||
 426                                   errno == EINPROGRESS || errno == ENOTCONN)
 427                                 continue;
 428
 429                               /* else failed */
 430                               so->so_state = SS_NOFDREF;
 431                             }
 432                             /* else so->so_state &= ~SS_ISFCONNECTING; */
 433
 434                             /*
 435                              * Continue tcp_input
 436                              */
 437                             tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
 438                             /* continue; */
 439                           } else
 440                             ret = sowrite(so);
 441                           /*
 442                            * XXXXX If we wrote something (a lot), there
 443                            * could be a need for a window update.
 444                            * In the worst case, the remote will send
 445                            * a window probe to get things going again
 446                            */
 447                         }
 448
 449                         /*
 450                          * Probe a still-connecting, non-blocking socket
 451                          * to check if it's still alive
 452                          */
 453 #ifdef PROBE_CONN
 454                         if (so->so_state & SS_ISFCONNECTING) {
 455                           ret = recv(so->s, (char *)&ret, 0,0);
 456
 457                           if (ret < 0) {
 458                             /* XXX */
 459                             if (errno == EAGAIN || errno == EWOULDBLOCK ||
 460                                 errno == EINPROGRESS || errno == ENOTCONN)
 461                               continue; /* Still connecting, continue */
 462
 463                             /* else failed */
 464                             so->so_state = SS_NOFDREF;
 465
 466                             /* tcp_input will take care of it */
 467                           } else {
 468                             ret = send(so->s, &ret, 0,0);
 469                             if (ret < 0) {
 470                               /* XXX */
 471                               if (errno == EAGAIN || errno == EWOULDBLOCK ||
 472                                   errno == EINPROGRESS || errno == ENOTCONN)
 473                                 continue;
 474                               /* else failed */
 475                               so->so_state = SS_NOFDREF;
 476                             } else
 477                               so->so_state &= ~SS_ISFCONNECTING;
 478
 479                           }
 480                           tcp_input((struct mbuf *)NULL, sizeof(struct ip),so);
 481                         } /* SS_ISFCONNECTING */
 482 #endif
 483                 }
 484
 485                 /*
 486                  * Now UDP sockets.
 487                  * Incoming packets are sent straight away, they're not buffered.
 488                  * Incoming UDP data isn't buffered either.
 489                  */
 490                 for (so = udb.so_next; so != &udb; so = so_next) {
 491                         so_next = so->so_next;
 492
 493                         if (so->s != -1 && FD_ISSET(so->s, readfds)) {
 494                             sorecvfrom(so);
 495                         }
 496                 }
 497         }
 498
 499         /*
 500          * See if we can start outputting
 501          */
 502         if (if_queued && link_up)
 503            if_start();
 504
 505         /* clear global file descriptor sets.
 506          * these reside on the stack in vl.c
 507          * so they're unusable if we're not in
 508          * slirp_select_fill or slirp_select_poll.
 509          */
 510          global_readfds = NULL;
 511          global_writefds = NULL;
 512          global_xfds = NULL;
 513 }
 514
 515 #define ETH_ALEN 6
 516 #define ETH_HLEN 14
 517
 518 #define ETH_P_IP        0x0800          /* Internet Protocol packet     */
 519 #define ETH_P_ARP       0x0806          /* Address Resolution packet    */
 520
 521 #define ARPOP_REQUEST   1               /* ARP request                  */
 522 #define ARPOP_REPLY     2               /* ARP reply                    */
 523
 524 struct ethhdr
 525 {
 526         unsigned char   h_dest[ETH_ALEN];       /* destination eth addr */
 527         unsigned char   h_source[ETH_ALEN];     /* source ether addr    */
 528         unsigned short  h_proto;                /* packet type ID field */
 529 };
 530
 531 struct arphdr
 532 {
 533         unsigned short  ar_hrd;         /* format of hardware address   */
 534         unsigned short  ar_pro;         /* format of protocol address   */
 535         unsigned char   ar_hln;         /* length of hardware address   */
 536         unsigned char   ar_pln;         /* length of protocol address   */
 537         unsigned short  ar_op;          /* ARP opcode (command)         */
 538
 539          /*
 540           *      Ethernet looks like this : This bit is variable sized however...
 541           */
 542         unsigned char           ar_sha[ETH_ALEN];       /* sender hardware address      */
 543         unsigned char           ar_sip[4];              /* sender IP address            */
 544         unsigned char           ar_tha[ETH_ALEN];       /* target hardware address      */
 545         unsigned char           ar_tip[4];              /* target IP address            */
 546 };
 547
 548 void arp_input(const uint8_t *pkt, int pkt_len)
 549 {
 550     struct ethhdr *eh = (struct ethhdr *)pkt;
 551     struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN);
 552     uint8_t arp_reply[ETH_HLEN + sizeof(struct arphdr)];
 553     struct ethhdr *reh = (struct ethhdr *)arp_reply;
 554     struct arphdr *rah = (struct arphdr *)(arp_reply + ETH_HLEN);
 555     int ar_op;
 556     struct ex_list *ex_ptr;
 557
 558     ar_op = ntohs(ah->ar_op);
 559     switch(ar_op) {
 560     case ARPOP_REQUEST:
 561         if (!memcmp(ah->ar_tip, &special_addr, 3)) {
 562             if (ah->ar_tip[3] == CTL_DNS || ah->ar_tip[3] == CTL_ALIAS)
 563                 goto arp_ok;
 564             for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
 565                 if (ex_ptr->ex_addr == ah->ar_tip[3])
 566                     goto arp_ok;
 567             }
 568             return;
 569         arp_ok:
 570             /* XXX: make an ARP request to have the client address */
 571             memcpy(client_ethaddr, eh->h_source, ETH_ALEN);
 572
 573             /* ARP request for alias/dns mac address */
 574             memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN);
 575             memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 1);
 576             reh->h_source[5] = ah->ar_tip[3];
 577             reh->h_proto = htons(ETH_P_ARP);
 578
 579             rah->ar_hrd = htons(1);
 580             rah->ar_pro = htons(ETH_P_IP);
 581             rah->ar_hln = ETH_ALEN;
 582             rah->ar_pln = 4;
 583             rah->ar_op = htons(ARPOP_REPLY);
 584             memcpy(rah->ar_sha, reh->h_source, ETH_ALEN);
 585             memcpy(rah->ar_sip, ah->ar_tip, 4);
 586             memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);
 587             memcpy(rah->ar_tip, ah->ar_sip, 4);
 588             slirp_output(arp_reply, sizeof(arp_reply));
 589         }
 590         break;
 591     default:
 592         break;
 593     }
 594 }
 595
 596 void slirp_input(const uint8_t *pkt, int pkt_len)
 597 {
 598     struct mbuf *m;
 599     int proto;
 600
 601     if (pkt_len < ETH_HLEN)
 602         return;
 603
 604     proto = ntohs(*(uint16_t *)(pkt + 12));
 605     switch(proto) {
 606     case ETH_P_ARP:
 607         arp_input(pkt, pkt_len);
 608         break;
 609     case ETH_P_IP:
 610         m = m_get();
 611         if (!m)
 612             return;
 613         /* Note: we add to align the IP header */
 614         m->m_len = pkt_len + 2;
 615         memcpy(m->m_data + 2, pkt, pkt_len);
 616
 617         m->m_data += 2 + ETH_HLEN;
 618         m->m_len -= 2 + ETH_HLEN;
 619
 620         ip_input(m);
 621         break;
 622     default:
 623         break;
 624     }
 625 }
 626
 627 /* output the IP packet to the ethernet device */
 628 void if_encap(const uint8_t *ip_data, int ip_data_len)
 629 {
 630     uint8_t buf[1600];
 631     struct ethhdr *eh = (struct ethhdr *)buf;
 632
 633     if (ip_data_len + ETH_HLEN > sizeof(buf))
 634         return;
 635
 636     memcpy(eh->h_dest, client_ethaddr, ETH_ALEN);
 637     memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1);
 638     /* XXX: not correct */
 639     eh->h_source[5] = CTL_ALIAS;
 640     eh->h_proto = htons(ETH_P_IP);
 641     memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len);
 642     slirp_output(buf, ip_data_len + ETH_HLEN);
 643 }
 644
 645 int slirp_redir(int is_udp, int host_port,
 646                 struct in_addr guest_addr, int guest_port)
 647 {
 648     if (is_udp) {
 649         if (!udp_listen(htons(host_port), guest_addr.s_addr,
 650                         htons(guest_port), 0))
 651             return -1;
 652     } else {
 653         if (!solisten(htons(host_port), guest_addr.s_addr,
 654                       htons(guest_port), 0))
 655             return -1;
 656     }
 657     return 0;
 658 }
 659
 660 int slirp_add_exec(int do_pty, const char *args, int addr_low_byte,
 661                   int guest_port)
 662 {
 663     return add_exec(&exec_list, do_pty, (char *)args,
 664                     addr_low_byte, htons(guest_port));
 665 }