Usermode/Applications/dhcpclient_src/main.c

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