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                 tInterface      *p;
 113
 114                 maxfd = 0;
 115                 FD_ZERO(&fds);
 116                 for( i = ifaces; i; i = i->Next )
 117                 {
 118                         FD_SET(i->SocketFD, &fds);
 119                         if(maxfd < i->SocketFD) maxfd = i->SocketFD;
 120                 }
 121                 if( select(maxfd+1, &fds, NULL, NULL, NULL) < 0 )
 122                 {
 123                         // TODO: Check error result
 124                         return -1;
 125                 }
 126
 127                 // Check for changes (with magic to allow inline deletion)
 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                 // Check if the device type is 9 (Network)
 162                 if( ioctl(fd, 0, NULL) != 9 )
 163                         continue ;
 164
 165                 // Check if it's a directory
 166                 finfo(fd, &info, 0);
 167                 if( info.flags & FILEFLAG_DIRECTORY )
 168                 {
 169                         // If so, recurse
 170                         Scan_Dir(IfaceList, path);
 171                 }
 172                 else
 173                 {
 174                         // Otherwise, add it to the list
 175                         tInterface      *new = malloc(sizeof(tInterface) + pathlen);
 176                         new->Adapter = (void*)(new + 1);
 177                         strcpy(new->Adapter, path);
 178                         new->Next = *IfaceList;
 179                         *IfaceList = new;
 180                 }
 181         }
 182         close(dp);
 183 }
 184
 185 // RETURN: Client FD
 186 int Start_Interface(tInterface *Iface)
 187 {
 188          int    fd, tmp;
 189         char    path[] = "/Devices/ip/XXXXX/udpc";
 190         char    addr[4] = {0,0,0,0};
 191
 192         // TODO: Check that the adapter is not in use
 193
 194         // Initialise an interface, with a dummy IP address (zero)
 195         fd = open("/Devices/ip", 0);
 196         if( fd == -1 ) {
 197                 fprintf(stderr, "ERROR: Unable to open '/Devices/ip'\n");
 198                 return -1;
 199         }
 200         Iface->Num = ioctl(fd, 4, (void*)Iface->Adapter);       // Create interface
 201         if( Iface->Num == -1 ) {
 202                 fprintf(stderr, "ERROR: Unable to create new interface\n");
 203                 return -1;
 204         }
 205         close(fd);
 206
 207         // Open new interface
 208         snprintf(path, sizeof(path), "/Devices/ip/%i", Iface->Num);
 209         Iface->IfaceFD = fd = open(path, 0);
 210         if( fd == -1 ) {
 211                 fprintf(stderr, "ERROR: Unable to open '%s'\n", path);
 212                 return -1;
 213         }
 214         tmp = 4; ioctl(fd, 4, &tmp);    // Set to IPv4
 215         ioctl(fd, 6, addr);     // Set address to 0.0.0.0
 216         tmp = 0; ioctl(fd, 7, &tmp);    // Set subnet mask to 0
 217
 218         // Open UDP Client
 219         snprintf(path, sizeof(path), "/Devices/ip/%i/udp", Iface->Num);
 220         Iface->SocketFD = fd = open(path, O_RDWR);
 221         if( fd == -1 ) {
 222                 fprintf(stderr, "ERROR: Unable to open '%s'\n", path);
 223                 return -1;
 224         }
 225         tmp = 68; ioctl(fd, 4, &tmp);   // Local port
 226         tmp = 67; ioctl(fd, 5, &tmp);   // Remote port
 227         tmp = 0;        ioctl(fd, 7, &tmp);     // Remote addr mask - we don't care where the reply comes from
 228         addr[0] = addr[1] = addr[2] = addr[3] = 255;    // 255.255.255.255
 229         ioctl(fd, 8, addr);     // Remote address
 230
 231         return fd;
 232 }
 233
 234 void Send_DHCPDISCOVER(tInterface *Iface)
 235 {
 236         uint32_t        transaction_id;
 237         struct sDHCP_Message    *msg;
 238         char    data[8 + sizeof(struct sDHCP_Message) + 3 + 1];
 239         msg = (void*)data + 8;
 240
 241         transaction_id = rand();
 242
 243         msg->op    = htonb(1);  // BOOTREQUEST
 244         msg->htype = htonb(1);  // 10mb Ethernet
 245         msg->hlen  = htonb(6);  // 6 byte MAC
 246         msg->hops  = htonb(0);  // Hop count so far
 247         msg->xid   = htonl(transaction_id);     // Transaction ID
 248         msg->secs  = htons(0);  // secs - No time has elapsed
 249         msg->flags = htons(0);  // flags - TODO: Check if broadcast bit need be set
 250         msg->ciaddr = htonl(0); // ciaddr - Zero, as we don't have one yet
 251         msg->yiaddr = htonl(0); // yiaddr - Zero?
 252         msg->siaddr = htonl(0); // siaddr - Zero? maybe -1
 253         msg->giaddr = htonl(0); // giaddr - Zero?
 254         // Request MAC address from network adapter
 255         {
 256                 int fd = open(Iface->Adapter, 0);
 257                 // TODO: Check if open() failed
 258                 ioctl(fd, 4, msg->chaddr);
 259                 // TODO: Check if ioctl() failed
 260                 close(fd);
 261         }
 262         memset(msg->sname, 0, sizeof(msg->sname));      // Nuke the rest
 263         memset(msg->file, 0, sizeof(msg->file));        // Nuke the rest
 264         msg->dhcp_magic = htonl(DHCP_MAGIC);
 265
 266         int i = 0;
 267         msg->options[i++] =  53;        // DHCP Message Type
 268         msg->options[i++] =   1;
 269         msg->options[i++] =   1;        // - DHCPDISCOVER
 270         msg->options[i++] = 255;        // End of list
 271
 272
 273         data[0] = 67;   data[1] = 0;    // Port
 274         data[2] = 4;    data[3] = 0;    // AddrType
 275         data[4] = 255;  data[5] = 255;  data[6] = 255;  data[7] = 255;
 276
 277         write(Iface->SocketFD, data, sizeof(data));
 278         Iface->State = STATE_DISCOVER_SENT;
 279 }
 280
 281 void Send_DHCPREQUEST(tInterface *Iface, void *OfferPacket, int TypeOffset)
 282 {
 283         struct sDHCP_Message    *msg;
 284         msg = (void*) ((char*)OfferPacket) + 8;
 285
 286         // Reuses old data :)
 287         msg->op = 1;
 288         msg->options[TypeOffset+2] = 3; // DHCPREQUEST
 289         msg->options[TypeOffset+3] = 255;
 290
 291         write(Iface->SocketFD, OfferPacket, 8 + sizeof(*msg) + TypeOffset + 4);
 292         Iface->State = STATE_REQUEST_SENT;
 293 }
 294
 295 int Handle_Packet(tInterface *Iface)
 296 {
 297         char    data[8+576];
 298         struct sDHCP_Message    *msg = (void*)(data + 8);
 299          int    len, i;
 300
 301          int    dhcp_msg_type = 0, dhcp_msg_type_ofs;
 302         void    *router = NULL;
 303         void    *subnet_mask = NULL;
 304
 305         _SysDebug("Doing read on %i", Iface->SocketFD);
 306         len = read(Iface->SocketFD, data, sizeof(data));
 307         _SysDebug("len = %i", len);
 308
 309         _SysDebug("*msg = {");
 310         _SysDebug("  .op = %i", msg->op);
 311         _SysDebug("  .htype = %i", msg->htype);
 312         _SysDebug("  .ciaddr = 0x%x", ntohl(msg->ciaddr));
 313         _SysDebug("  .yiaddr = 0x%x", ntohl(msg->yiaddr));
 314         _SysDebug("}");
 315         if( msg->op != 2 ) {
 316                 // Not a response
 317                 _SysDebug("Not a response message");
 318                 return 0;
 319         }
 320
 321         if( htonl(msg->dhcp_magic) != DHCP_MAGIC ) {
 322                 _SysDebug("DHCP magic doesn't match (got 0x%x, expected 0x%x)",
 323                         htonl(msg->dhcp_magic), DHCP_MAGIC);
 324                 return 0;
 325         }
 326
 327         i = 0;
 328         while( i < len - sizeof(*msg) - 8 && msg->options[i] != 255 )
 329         {
 330                 if( msg->options[i] == 0 ) {
 331                         i ++;
 332                         continue ;
 333                 }
 334                 _SysDebug("Option %i, %i bytes long", msg->options[i], msg->options[i+1]);
 335                 switch(msg->options[i])
 336                 {
 337                 case 1:
 338                         subnet_mask = &msg->options[i+2];
 339                         break;
 340                 case 3:
 341                         router = &msg->options[i+2];
 342                         break;
 343                 case 53:
 344                         dhcp_msg_type_ofs = i;
 345                         dhcp_msg_type = msg->options[i+2];
 346                         break;
 347                 }
 348                 i += msg->options[i+1]+2;
 349         }
 350
 351         _SysDebug("dhcp_msg_type = %i", dhcp_msg_type);
 352
 353         switch( dhcp_msg_type )
 354         {
 355         case 1: // DHCPDISCOVER - wut?
 356                 break;
 357         case 2: // DHCPOFFER
 358                 // Send out request for this address
 359                 if( Iface->State != STATE_DISCOVER_SENT )       return 0;
 360                 Send_DHCPREQUEST(Iface, data, dhcp_msg_type_ofs);
 361                 break;
 362         case 3: // DHCPREQUEST - wut?
 363                 break;
 364         case 4: // DHCPDECLINE - ?
 365                 break;
 366         case 5: // DHCPACK
 367                 // TODO: Apply address
 368                 SetAddress(Iface, &msg->yiaddr, subnet_mask, router);
 369                 return 1;
 370         }
 371         return 0;
 372 }
 373
 374 void SetAddress(tInterface *Iface, void *Addr, void *Mask, void *Router)
 375 {
 376          int    mask_bits = 0;
 377
 378         // Translate the mask
 379         if( Mask )
 380         {
 381                 uint8_t *mask = Mask;
 382                  int    i;
 383                 _SysDebug("Mask %i.%i.%i.%i", mask[0], mask[1], mask[2], mask[3]);
 384                 for( i = 0; i < 4 && mask[i] == 0xFF; i ++ ) ;
 385                 mask_bits = i*8;
 386                 if( i == 4 )
 387                 {
 388                         // Wut? /32?
 389                 }
 390                 else
 391                 {
 392                         switch(mask[i])
 393                         {
 394                         case 0x00:      mask_bits += 0; break;
 395                         case 0x80:      mask_bits += 1; break;
 396                         case 0xC0:      mask_bits += 2; break;
 397                         case 0xE0:      mask_bits += 3; break;
 398                         case 0xF0:      mask_bits += 4; break;
 399                         case 0xF8:      mask_bits += 5; break;
 400                         case 0xFC:      mask_bits += 6; break;
 401                         case 0xFE:      mask_bits += 7; break;
 402                         default:
 403                                 // Bad mask!
 404                                 break;
 405                         }
 406                 }
 407         }
 408
 409         {
 410                 uint8_t *addr = Addr;
 411                 _SysDebug("Addr %i.%i.%i.%i/%i", addr[0], addr[1], addr[2], addr[3], mask_bits);
 412
 413                 printf("Assigned %i.%i.%i.%i/%i to IF#%i (%s)\n",
 414                         addr[0], addr[1], addr[2], addr[3], mask_bits,
 415                         Iface->Num, Iface->Adapter
 416                         );
 417         }
 418
 419         ioctl(Iface->IfaceFD, 6, Addr);
 420         ioctl(Iface->IfaceFD, 7, &mask_bits);
 421
 422         if( Router );
 423         {
 424                 uint8_t *addr = Router;
 425                 _SysDebug("Router %i.%i.%i.%i", addr[0], addr[1], addr[2], addr[3]);
 426
 427                 // Set default route
 428                  int    fd;
 429                 fd = open("/Devices/ip/routes/4:00000000:0:0", OPENFLAG_CREATE);
 430                 if(fd == -1) {
 431                         fprintf(stderr, "ERROR: Unable to open default route\n");
 432                 }
 433                 else {
 434                         char ifname[snprintf(NULL,0,"%i",Iface->Num)+1];
 435                         sprintf(ifname, "%i", Iface->Num);
 436                         ioctl(fd, ioctl(fd, 3, "set_nexthop"), Router);
 437                         ioctl(fd, ioctl(fd, 3, "set_interface"), ifname);
 438                         close(fd);
 439                 }
 440         }
 441 }
 442