Usermode/Applications/dhcpclient_src/main.c

   1 /*
   2  *
   3  * http://www.ietf.org/rfc/rfc2131.txt
   4  */
   5 #include <unistd.h>
   6 #include <stdint.h>
   7 #include <stdio.h>
   8 #include <string.h>
   9 #include <stdlib.h>
  10 #include <net.h>
  11
  12 #define FILENAME_MAX    255
  13 // --- Translation functions ---
  14 static inline uint32_t htonl(uint32_t v)
  15 {
  16         return    (((v >> 24) & 0xFF) <<  0)
  17                 | (((v >> 16) & 0xFF) <<  8)
  18                 | (((v >>  8) & 0xFF) << 16)
  19                 | (((v >>  0) & 0xFF) << 24);
  20 }
  21 static inline uint16_t htons(uint16_t v)
  22 {
  23         return    (((v >> 8) & 0xFF) <<  0)
  24                 | (((v >> 0) & 0xFF) <<  8);
  25 }
  26 #define htonb(v)        v
  27 #define ntohl(v)        htonl(v)
  28 #define ntohs(v)        htons(v)
  29
  30 // === CONSTANTS ===
  31 enum eStates
  32 {
  33         STATE_PREINIT,
  34         STATE_DISCOVER_SENT,
  35         STATE_REQUEST_SENT,
  36         STATE_COMPLETE
  37 };
  38
  39 // === STRUCTURES ===
  40 #define DHCP_MAGIC      0x63825363
  41 struct sDHCP_Message
  42 {
  43         uint8_t op;
  44         uint8_t htype;  // 1 = Ethernet
  45         uint8_t hlen;   // 6 bytes for MAC
  46         uint8_t hops;   // Hop counting
  47         uint32_t        xid;
  48         uint16_t        secs;
  49         uint16_t        flags;
  50         uint32_t        ciaddr;
  51         uint32_t        yiaddr;
  52         uint32_t        siaddr;
  53         uint32_t        giaddr;
  54         uint8_t chaddr[16];
  55         uint8_t sname[64];
  56         uint8_t file[128];
  57         uint32_t        dhcp_magic;     // 0x63 0x82 0x53 0x63
  58         uint8_t options[];
  59 };
  60
  61 typedef struct sInterface
  62 {
  63         struct sInterface       *Next;
  64         char    *Adapter;
  65          int    State;
  66          int    Num;
  67          int    SocketFD;
  68          int    IfaceFD;
  69
  70         uint32_t        TransactionID;
  71         char    HWAddr[6];
  72
  73         int64_t Timeout;
  74 } tInterface;
  75
  76 // === PROTOTYPES ===
  77 int     main(int argc, char *argv[]);
  78 void    Scan_Dir(tInterface **IfaceList, const char *Directory);
  79 int     Start_Interface(tInterface *Iface);
  80 void    Send_DHCPDISCOVER(tInterface *Iface);
  81 void    Send_DHCPREQUEST(tInterface *Iface, void *OfferBuffer, int TypeOffset);
  82 int     Handle_Packet(tInterface *Iface);
  83 void    Handle_Timeout(tInterface *Iface);
  84 void    Update_State(tInterface *Iface, int newState);
  85 void    SetAddress(tInterface *Iface, void *Addr, void *Mask, void *Router);
  86
  87 // === CODE ===
  88 int main(int argc, char *argv[])
  89 {
  90         tInterface      *ifaces = NULL, *i;
  91
  92         // TODO: Scan /Devices and search for network adapters
  93         if( argc > 2 ) {
  94                 fprintf(stderr, "Usage: %s <interface>\n", argv[0]);
  95                 return -1;
  96         }
  97
  98         if( argc == 2 ) {
  99                 ifaces = malloc(sizeof(tInterface));
 100                 ifaces->Next = NULL;
 101                 ifaces->Adapter = argv[1];
 102         }
 103         else {
 104                 Scan_Dir( &ifaces, "/Devices/ip/adapters" );
 105         }
 106
 107         for( i = ifaces; i; i = i->Next )
 108         {
 109                 if( Start_Interface(i) < 0 ) {
 110                         return -1;
 111                 }
 112                 i->State = STATE_PREINIT;
 113
 114                 // Send request
 115                 Send_DHCPDISCOVER(i);
 116         }
 117
 118         while( ifaces )
 119         {
 120                  int    maxfd;
 121                 fd_set  fds;
 122                 tInterface      *p;
 123                 int64_t timeout = 1000;
 124
 125                 maxfd = 0;
 126                 FD_ZERO(&fds);
 127                 for( i = ifaces; i; i = i->Next )
 128                 {
 129                         FD_SET(i->SocketFD, &fds);
 130                         if(maxfd < i->SocketFD) maxfd = i->SocketFD;
 131                 }
 132
 133                 if( select(maxfd+1, &fds, NULL, NULL, &timeout) < 0 )
 134                 {
 135                         // TODO: Check error result
 136                         return -1;
 137                 }
 138
 139                 _SysDebug("select() returned");
 140
 141                 // Check for changes (with magic to allow inline deletion)
 142                 for( p = (void*)&ifaces, i = ifaces; i; p=i,i = i->Next )
 143                 {
 144                         if( FD_ISSET(i->SocketFD, &fds) )
 145                         {
 146                                 if( Handle_Packet( i ) )
 147                                 {
 148                                         close(i->SocketFD);
 149                                         close(i->IfaceFD);
 150                                         p->Next = i->Next;
 151                                         free(i);
 152                                         i = p;
 153                                 }
 154                         }
 155
 156                         if( _SysTimestamp() > i->Timeout )
 157                         {
 158                                 Handle_Timeout(i);
 159                         }
 160                 }
 161         }
 162         return 0;
 163 }
 164
 165 void Scan_Dir(tInterface **IfaceList, const char *Directory)
 166 {
 167         int dp = open(Directory, OPENFLAG_READ);
 168         char filename[FILENAME_MAX];
 169
 170         if( dp == -1 ) {
 171                 fprintf(stderr, "Unable to open directory '%s'\n", Directory);
 172         }
 173
 174         while( readdir(dp, filename) )
 175         {
 176                 if( filename[0] == '.' )        continue ;
 177                 if( strcmp(filename, "lo") == 0 )       continue ;
 178
 179                 tInterface *new = malloc(sizeof(tInterface) + strlen(filename)+1);
 180                 new->Adapter = (void*)(new + 1);
 181                 strcpy(new->Adapter, filename);
 182                 new->Next = *IfaceList;
 183                 *IfaceList = new;
 184         }
 185         close(dp);
 186 }
 187
 188 // RETURN: Client FD
 189 int Start_Interface(tInterface *Iface)
 190 {
 191          int    fd, tmp;
 192         char    path[] = "/Devices/ip/XXXXX/udpc";
 193         char    addr[4] = {0,0,0,0};
 194
 195         // TODO: Check that the adapter is not in use
 196
 197         // Request MAC address from network adapter
 198         {
 199                 char    path[] = "/Devices/ip/adapters/ethXXXX";
 200                 sprintf(path, "/Devices/ip/adapters/%s", Iface->Adapter);
 201                 fd = open(path, 0);
 202                 if(fd == -1) {
 203                         _SysDebug("Unable to open adapter %s", path);
 204                         return -1;
 205                 }
 206                 ioctl(fd, 4, Iface->HWAddr);
 207                 // TODO: Check if ioctl() failed
 208                 close(fd);
 209         }
 210
 211         // Initialise an interface, with a dummy IP address (zero)
 212         fd = open("/Devices/ip", 0);
 213         if( fd == -1 ) {
 214                 fprintf(stderr, "ERROR: Unable to open '/Devices/ip'\n");
 215                 return -1;
 216         }
 217         Iface->Num = ioctl(fd, 4, (void*)Iface->Adapter);       // Create interface
 218         if( Iface->Num == -1 ) {
 219                 fprintf(stderr, "ERROR: Unable to create new interface\n");
 220                 return -1;
 221         }
 222         close(fd);
 223
 224         // Open new interface
 225         snprintf(path, sizeof(path), "/Devices/ip/%i", Iface->Num);
 226         Iface->IfaceFD = fd = open(path, 0);
 227         if( fd == -1 ) {
 228                 fprintf(stderr, "ERROR: Unable to open '%s'\n", path);
 229                 return -1;
 230         }
 231         tmp = 4; ioctl(fd, 4, &tmp);    // Set to IPv4
 232         ioctl(fd, 6, addr);     // Set address to 0.0.0.0
 233         tmp = 0; ioctl(fd, 7, &tmp);    // Set subnet mask to 0
 234
 235         // Open UDP Client
 236         snprintf(path, sizeof(path), "/Devices/ip/%i/udp", Iface->Num);
 237         Iface->SocketFD = fd = open(path, O_RDWR);
 238         if( fd == -1 ) {
 239                 fprintf(stderr, "ERROR: Unable to open '%s'\n", path);
 240                 return -1;
 241         }
 242         tmp = 68; ioctl(fd, 4, &tmp);   // Local port
 243         tmp = 67; ioctl(fd, 5, &tmp);   // Remote port
 244         tmp = 0;        ioctl(fd, 7, &tmp);     // Remote addr mask bits - we don't care where the reply comes from
 245         addr[0] = addr[1] = addr[2] = addr[3] = 255;    // 255.255.255.255
 246         ioctl(fd, 8, addr);     // Remote address
 247
 248         return 0;
 249 }
 250
 251 void Send_DHCPRELEASE(tInterface *Iface)
 252 {
 253 }
 254
 255 void Send_DHCPDISCOVER(tInterface *Iface)
 256 {
 257         uint32_t        transaction_id;
 258         struct sDHCP_Message    *msg;
 259         char    data[8 + sizeof(struct sDHCP_Message) + 3 + 1];
 260         msg = (void*)data + 8;
 261
 262         _SysDebug("DHCPDISCOVER to %s", Iface->Adapter);
 263
 264         transaction_id = rand();
 265         Iface->TransactionID = transaction_id;
 266
 267         msg->op    = htonb(1);  // BOOTREQUEST
 268         msg->htype = htonb(1);  // 10mb Ethernet
 269         msg->hlen  = htonb(6);  // 6 byte MAC
 270         msg->hops  = htonb(0);  // Hop count so far
 271         msg->xid   = htonl(transaction_id);     // Transaction ID
 272         msg->secs  = htons(0);  // secs - No time has elapsed
 273         msg->flags = htons(0x0000);     // flags - Broadcast is unset
 274         msg->ciaddr = htonl(0); // ciaddr - Zero, as we don't have one yet
 275         msg->yiaddr = htonl(0); // yiaddr - Zero?
 276         msg->siaddr = htonl(0); // siaddr - Zero? maybe -1
 277         msg->giaddr = htonl(0); // giaddr - Zero?
 278         memcpy(msg->chaddr, Iface->HWAddr, 6);
 279
 280         memset(msg->sname, 0, sizeof(msg->sname));      // Nuke the rest
 281         memset(msg->file, 0, sizeof(msg->file));        // Nuke the rest
 282         msg->dhcp_magic = htonl(DHCP_MAGIC);
 283
 284         int i = 0;
 285         msg->options[i++] =  53;        // DHCP Message Type
 286         msg->options[i++] =   1;
 287         msg->options[i++] =   1;        // - DHCPDISCOVER
 288         msg->options[i++] = 255;        // End of list
 289
 290
 291         data[0] = 67;   data[1] = 0;    // Port
 292         data[2] = 4;    data[3] = 0;    // AddrType
 293         data[4] = 255;  data[5] = 255;  data[6] = 255;  data[7] = 255;
 294
 295         write(Iface->SocketFD, data, sizeof(data));
 296         Update_State(Iface, STATE_DISCOVER_SENT);
 297 }
 298
 299 void Send_DHCPREQUEST(tInterface *Iface, void *OfferPacket, int TypeOffset)
 300 {
 301         struct sDHCP_Message    *msg;
 302          int    i;
 303         msg = (void*) ((char*)OfferPacket) + 8;
 304
 305         // Reuses old data :)
 306         msg->op    = 1;
 307         msg->htype = 1;
 308         msg->hlen  = 6;
 309         msg->hops  = 0;
 310         msg->xid   = msg->xid;
 311         msg->secs  = htons(0);  // TODO: Maintain times
 312         msg->flags = htons(0);
 313         memcpy(msg->chaddr, Iface->HWAddr, 6);
 314         memset(msg->sname, 0, sizeof(msg->sname));      // Nuke the rest
 315         memset(msg->file, 0, sizeof(msg->file));        // Nuke the rest
 316
 317         i = 0;
 318         msg->options[i++] = 53; // Message type = DHCPREQUEST
 319         msg->options[i++] = 1;
 320         msg->options[i++] = 3;
 321         msg->options[i++] = 50; // Requested Address
 322         msg->options[i++] = 4;
 323         memcpy(msg->options + i, &msg->yiaddr, 4);      i += 4;
 324 //      msg->options[i++] = 54; // Server identifier
 325 //      msg->options[i++] = 4;
 326 //      memcpy(msg->options + i, (char*)OfferPacket + 4, 4);    i += 4;
 327         msg->options[i++] = 255;
 328
 329         // Clear last because yiaddr is needed in option setup
 330         msg->ciaddr = htonl(0);
 331         msg->yiaddr = htonl(0);
 332         msg->siaddr = htonl(0);
 333         msg->giaddr = htonl(0);
 334
 335         // HACK
 336         ((uint8_t*)OfferPacket)[4] = 255;
 337         ((uint8_t*)OfferPacket)[5] = 255;
 338         ((uint8_t*)OfferPacket)[6] = 255;
 339         ((uint8_t*)OfferPacket)[7] = 255;
 340
 341         write(Iface->SocketFD, OfferPacket, 8 + sizeof(*msg) + i);
 342         Update_State(Iface, STATE_REQUEST_SENT);
 343 }
 344
 345 int Handle_Packet(tInterface *Iface)
 346 {
 347         char    data[8+576];
 348         struct sDHCP_Message    *msg = (void*)(data + 8);
 349          int    len, i;
 350
 351          int    dhcp_msg_type = 0, dhcp_msg_type_ofs;
 352         void    *router = NULL;
 353         void    *subnet_mask = NULL;
 354
 355         _SysDebug("Doing read on %i", Iface->SocketFD);
 356         len = read(Iface->SocketFD, data, sizeof(data));
 357         _SysDebug("len = %i", len);
 358
 359         _SysDebug("*msg = {");
 360         _SysDebug("  .op = %i", msg->op);
 361         _SysDebug("  .htype = %i", msg->htype);
 362         _SysDebug("  .ciaddr = 0x%x", ntohl(msg->ciaddr));
 363         _SysDebug("  .yiaddr = 0x%x", ntohl(msg->yiaddr));
 364         _SysDebug("}");
 365         if( msg->op != 2 ) {
 366                 // Not a response
 367                 _SysDebug("Not a response message");
 368                 return 0;
 369         }
 370
 371         if( htonl(msg->dhcp_magic) != DHCP_MAGIC ) {
 372                 _SysDebug("DHCP magic doesn't match (got 0x%x, expected 0x%x)",
 373                         htonl(msg->dhcp_magic), DHCP_MAGIC);
 374                 return 0;
 375         }
 376
 377
 378         // Check if the packet is related to our requests
 379         if( ntohl(msg->xid) != Iface->TransactionID ) {
 380                 _SysDebug("Transaction ID mis-match, ignoring (0x%x != 0x%x)",
 381                         ntohl(msg->xid), Iface->TransactionID);
 382                 return 0;
 383         }
 384         if( memcmp(msg->chaddr, Iface->HWAddr, 6) != 0 ) {
 385                 _SysDebug("Hardware address mis-match, ignoring");
 386                 return 0;
 387         }
 388
 389         // Parse options
 390         i = 0;
 391         while( i < len - sizeof(*msg) - 8 && msg->options[i] != 255 )
 392         {
 393                 if( msg->options[i] == 0 ) {
 394                         i ++;
 395                         continue ;
 396                 }
 397                 _SysDebug("Option %i, %i bytes long", msg->options[i], msg->options[i+1]);
 398                 switch(msg->options[i])
 399                 {
 400                 case 1:
 401                         subnet_mask = &msg->options[i+2];
 402                         break;
 403                 case 3:
 404                         router = &msg->options[i+2];
 405                         break;
 406                 case 53:
 407                         dhcp_msg_type_ofs = i;
 408                         dhcp_msg_type = msg->options[i+2];
 409                         break;
 410                 }
 411                 i += msg->options[i+1]+2;
 412         }
 413
 414         _SysDebug("dhcp_msg_type = %i", dhcp_msg_type);
 415
 416         switch( dhcp_msg_type )
 417         {
 418         case 1: // DHCPDISCOVER - wut?
 419                 break;
 420         case 2: // DHCPOFFER
 421                 // Send out request for this address
 422                 if( Iface->State != STATE_DISCOVER_SENT ) {
 423                         _SysDebug("Ignoring DHCPOFFER when not in STATE_DISCOVER_SENT");
 424                         return 0;
 425                 }
 426                 Send_DHCPREQUEST(Iface, data, dhcp_msg_type_ofs);
 427                 break;
 428         case 3: // DHCPREQUEST - wut?
 429                 break;
 430         case 4: // DHCPDECLINE - ?
 431                 break;
 432         case 5: // DHCPACK
 433                 SetAddress(Iface, &msg->yiaddr, subnet_mask, router);
 434                 // Return 1 to remove from list
 435                 return 1;
 436         }
 437         return 0;
 438 }
 439
 440 void Handle_Timeout(tInterface *Iface)
 441 {
 442         switch(Iface->State)
 443         {
 444         case STATE_DISCOVER_SENT:
 445                 Send_DHCPDISCOVER(Iface);
 446                 break;
 447         default:
 448                 _SysDebug("Timeout with state = %i", Iface->State);
 449                 break;
 450         }
 451 }
 452
 453 void Update_State(tInterface *Iface, int newState)
 454 {
 455         if( Iface->State != newState )
 456         {
 457                 Iface->Timeout = _SysTimestamp() + 500;
 458                 Iface->State = newState;
 459         }
 460         else
 461         {
 462                 // TODO: Exponential backoff
 463                 Iface->Timeout = _SysTimestamp() + 3000;
 464                 _SysDebug("State %i repeated, timeout is 3000ms now", newState);
 465         }
 466 }
 467
 468 void SetAddress(tInterface *Iface, void *Addr, void *Mask, void *Router)
 469 {
 470          int    mask_bits = 0;
 471
 472         // Translate the mask
 473         if( Mask )
 474         {
 475                 uint8_t *mask = Mask;
 476                  int    i;
 477                 _SysDebug("Mask %i.%i.%i.%i", mask[0], mask[1], mask[2], mask[3]);
 478                 for( i = 0; i < 4 && mask[i] == 0xFF; i ++ ) ;
 479                 mask_bits = i*8;
 480                 if( i == 4 )
 481                 {
 482                         // Wut? /32?
 483                 }
 484                 else
 485                 {
 486                         switch(mask[i])
 487                         {
 488                         case 0x00:      mask_bits += 0; break;
 489                         case 0x80:      mask_bits += 1; break;
 490                         case 0xC0:      mask_bits += 2; break;
 491                         case 0xE0:      mask_bits += 3; break;
 492                         case 0xF0:      mask_bits += 4; break;
 493                         case 0xF8:      mask_bits += 5; break;
 494                         case 0xFC:      mask_bits += 6; break;
 495                         case 0xFE:      mask_bits += 7; break;
 496                         default:
 497                                 // Bad mask!
 498                                 break;
 499                         }
 500                 }
 501         }
 502
 503         {
 504                 uint8_t *addr = Addr;
 505                 _SysDebug("Addr %i.%i.%i.%i/%i", addr[0], addr[1], addr[2], addr[3], mask_bits);
 506
 507                 printf("Assigned %i.%i.%i.%i/%i to IF#%i (%s)\n",
 508                         addr[0], addr[1], addr[2], addr[3], mask_bits,
 509                         Iface->Num, Iface->Adapter
 510                         );
 511         }
 512
 513         ioctl(Iface->IfaceFD, 6, Addr);
 514         ioctl(Iface->IfaceFD, 7, &mask_bits);
 515
 516         if( Router );
 517         {
 518                 uint8_t *addr = Router;
 519                 _SysDebug("Router %i.%i.%i.%i", addr[0], addr[1], addr[2], addr[3]);
 520
 521                 // Set default route
 522                  int    fd;
 523                 fd = open("/Devices/ip/routes/4:00000000:0:0", OPENFLAG_CREATE);
 524                 if(fd == -1) {
 525                         fprintf(stderr, "ERROR: Unable to open default route\n");
 526                 }
 527                 else {
 528                         char ifname[snprintf(NULL,0,"%i",Iface->Num)+1];
 529                         sprintf(ifname, "%i", Iface->Num);
 530                         ioctl(fd, ioctl(fd, 3, "set_nexthop"), Router);
 531                         ioctl(fd, ioctl(fd, 3, "set_interface"), ifname);
 532                         close(fd);
 533                 }
 534         }
 535 }
 536