utils/cegw/cegw.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <libgen.h>
   4 #include <string.h>
   5 #include <getopt.h>
   6 #include <errno.h>
   7 #include <sys/socket.h>
   8 #include <net/if.h>
   9 #include <libnetlink.h>
  10 #include <linux/netlink.h>
  11 #include <linux/rtnetlink.h>
  12 #include <arpa/inet.h>
  13 #include <linux/can.h>
  14 #include <linux/types.h>
  15 #include <unistd.h>
  16 #include <sys/types.h>
  17 #include <sys/stat.h>
  18 #include <fcntl.h>
  19 #include <sys/ioctl.h>
  20 #include "canethgw.h"
  21
  22 /**
  23  * ToDo:
  24  * [ ] print usage, on -h and plain execution
  25  * [ ] start/stop listening
  26  * [ ] split to files
  27  */
  28
  29 #define CEGW_CMD_ADD     1
  30 #define CEGW_CMD_LIST    2
  31 #define CEGW_CMD_FLUSH   4
  32 #define CEGW_CMD_LISTEN  8
  33
  34 enum
  35 {
  36         IF_UNDEF,
  37         IF_CAN,
  38         IF_ETH_UDP
  39 };
  40
  41 struct cegw_data
  42 {
  43         int content;
  44         int src_if, dst_if;
  45         int can_ifidx;
  46         struct in_addr eth_addr;
  47         unsigned short eth_port;
  48         struct in_addr eth_listen_addr;
  49         unsigned short eth_listen_port;
  50 };
  51
  52 struct cegw_nlmsg
  53 {
  54         struct nlmsghdr nh;
  55         struct rtmsg rt;
  56         char buf[768]; /* enough? */
  57 };
  58
  59 struct list_item
  60 {
  61         int type;
  62         int can;
  63         struct in_addr ip;
  64         unsigned short port;
  65 };
  66
  67 unsigned int cegw_errno = 0;
  68
  69 enum
  70 {
  71         CEGW_ERR_UNKNOWN,
  72         CEGW_ERR_IF_UNSPEC,
  73         CEGW_ERR_IF_SAME,
  74         CEGW_ERR_IF_TYPE,
  75         CEGW_ERR_IF_CAN,
  76         CEGW_ERR_IF_ETH,
  77         CEGW_ERR_COLON,
  78         CEGW_ERR_ATON,
  79         CEGW_ERR_PORT
  80 };
  81
  82 char* cegw_errlist[] =
  83 {
  84         [ CEGW_ERR_UNKNOWN   ] = "",
  85         [ CEGW_ERR_IF_UNSPEC ] = "source or destination not specified",
  86         [ CEGW_ERR_IF_SAME   ] = "source and destination have same interface type",
  87         [ CEGW_ERR_IF_TYPE   ] = "unknown interface type",
  88         [ CEGW_ERR_IF_CAN    ] = "invalid can interface",
  89         [ CEGW_ERR_IF_ETH    ] = "invalid eth interface",
  90         [ CEGW_ERR_COLON     ] = "expected ':' (<ip>:<port>)",
  91         [ CEGW_ERR_ATON      ] = "ip address mismatch",
  92         [ CEGW_ERR_PORT      ] = "port number"
  93 };
  94
  95 static void perr( char* s )
  96 {
  97         if( s )
  98         {
  99                 if( cegw_errno == 0 )
 100                 {
 101                         fprintf( stderr, "error: %s\n", s );
 102
 103                 } else
 104                 {
 105                         fprintf( stderr, "error: %s, %s\n", s,
 106                                  cegw_errlist[ cegw_errno ] );
 107                 }
 108                 return;
 109         }
 110
 111         fprintf( stderr, "error: %s\n", cegw_errlist[ cegw_errno ] );
 112 }
 113
 114 /**
 115  * read_addrport - parses @in for eth address.
 116  * Valid input is e.g. udp@127.0.0.1:10502 or can@vcan0.
 117  *
 118  * @param[in]  in   string to search in
 119  * @param[out] addr ip address
 120  * @param[out] port transport layer port
 121  * @return 0 on success, -1 otherwise
 122  */
 123 int read_addrport( char* in, struct in_addr* addr, unsigned short* port )
 124 {
 125         char* delim = NULL;
 126         char addrstr[16];
 127         int addrlen;
 128
 129         if( (delim = strchr( in, ':' )) == NULL )
 130         {
 131                 cegw_errno = CEGW_ERR_COLON;
 132                 return -1;
 133         }
 134
 135         /* get address */
 136         addrlen = delim - in;
 137         memcpy( addrstr, in, addrlen );
 138         addrstr[addrlen] = '\0';
 139         if( inet_aton( addrstr, addr ) == 0 )
 140         {
 141                 cegw_errno = CEGW_ERR_ATON;
 142                 return -1;
 143         }
 144
 145         /* get port */
 146         if( sscanf( delim, ":%hu", port ) != 1 ) /* ToDo: handle overflow */
 147         {
 148                 cegw_errno = CEGW_ERR_PORT;
 149                 return -1;
 150         }
 151
 152         return 0;
 153 }
 154
 155 /**
 156  * read_iftype - reads @in for iftype
 157  * Iftype type is e.g. "can@" or "udp@".
 158  *
 159  * @param[in] in string to search in
 160  * @param[out] iftype iftype detected
 161  * @return pointer to @in after iftype on success, NULL otherwise
 162  */
 163 char* read_iftype( char* in, int* iftype )
 164 {
 165         char* ret = in+4;
 166
 167         if( strncmp( "udp@", optarg, 4 ) == 0 )
 168         {
 169                 *iftype = IF_ETH_UDP;
 170                 return ret;
 171         }
 172         /*
 173         if( strncmp( "tcp@", optarg, 4 ) == 0 )
 174         {
 175                 return NULL;
 176         }
 177         */
 178         if( strncmp( "can@", optarg, 4 ) == 0 )
 179         {
 180                 *iftype = IF_CAN;
 181                 return ret;
 182         }
 183
 184         cegw_errno = CEGW_ERR_IF_TYPE;
 185         return NULL;
 186 }
 187
 188 /* ToDo: move to common */
 189
 190 /**
 191  * read_if - reads interface from @in
 192  * Function analyzes @in for interface specification in format
 193  * <if>@<ip>:<port>, where <if> is can or udp, <ip> is address in dotted
 194  * format
 195  *
 196  * @param[in]  in string to search in
 197  * @param[out] iftype interface type (IF_CAN or IF_ETH_UDP)
 198  * @param[out] d ip and port is stored to @d
 199  */
 200 int read_if( char* in, int* iftype, struct cegw_data* d )
 201 {
 202         char* optstr = NULL;
 203
 204         if( (optstr = read_iftype( in, iftype )) == NULL )
 205         {
 206                 return -1;
 207         }
 208
 209         switch( *iftype )
 210         {
 211                 case IF_CAN:
 212                         d->can_ifidx = if_nametoindex( optstr );
 213                         if( d->can_ifidx == 0 )
 214                         {
 215                                 cegw_errno = CEGW_ERR_IF_CAN;
 216                                 return -1;
 217                         }
 218                         break;
 219                 case IF_ETH_UDP:
 220                         if( read_addrport( optstr, &d->eth_addr, &d->eth_port ) != 0 )
 221                         {
 222                                 return -1;
 223                         }
 224                         break;
 225                 default:
 226                         return -1;
 227                         break;
 228         }
 229
 230         return 0;
 231 }
 232
 233 inline static int cegw_add( struct cegw_nlmsg* req, struct cegw_data* d )
 234 {
 235         int gwtype = 0;
 236
 237         req->nh.nlmsg_type  = RTM_NEWROUTE;
 238         if( (d->src_if == 0 || d->dst_if == 0) )
 239         {
 240                 cegw_errno = CEGW_ERR_IF_UNSPEC;
 241                 return -cegw_errno;
 242         }
 243
 244         if( d->src_if == d->dst_if )
 245         {
 246                 cegw_errno = CEGW_ERR_IF_SAME;
 247                 return -cegw_errno;
 248         }
 249
 250         gwtype = (d->src_if == IF_CAN) ? CEGW_RULE_CAN_ETH : CEGW_RULE_ETH_CAN;
 251         addattr_l( &req->nh, sizeof(*req), CEGW_CAN_IFINDEX, &d->can_ifidx, sizeof(d->can_ifidx) );
 252         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_IP, &d->eth_addr, sizeof(d->eth_addr) );
 253         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_PORT, &d->eth_port, sizeof(d->eth_port) );
 254         addattr32( &req->nh, sizeof(*req), CEGW_CMD_INFO, gwtype );
 255
 256         return 0;
 257 }
 258
 259 inline static int cegw_listen( struct cegw_nlmsg* req, struct cegw_data* d )
 260 {
 261         req->nh.nlmsg_type = RTM_NEWROUTE;
 262         addattr32( &req->nh, sizeof(*req), CEGW_CMD_INFO, CEGW_LISTEN );
 263         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_IP, &d->eth_listen_addr, sizeof(d->eth_listen_addr) );
 264         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_PORT, &d->eth_listen_port, sizeof(d->eth_listen_port) );
 265
 266         return 0;
 267 }
 268
 269 inline static int cegw_list( struct cegw_nlmsg* req, struct cegw_data* d )
 270 {
 271         req->nh.nlmsg_type = RTM_GETROUTE;
 272         req->nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
 273
 274         return 0;
 275 }
 276
 277 inline static int cegw_flush( struct cegw_nlmsg* req, struct cegw_data* d )
 278 {
 279         addattr32( &req->nh, sizeof(*req), CEGW_CMD_INFO, CEGW_FLUSH );
 280         req->nh.nlmsg_type  = RTM_DELROUTE;
 281         return 0;
 282 }
 283
 284 void print_list_item( struct list_item* li )
 285 {
 286         char ifname[IF_NAMESIZE];
 287         const char src_width = 21;
 288         char* dotaddr;
 289         int tmp;
 290
 291         if( if_indextoname( li->can, ifname ) == NULL )
 292         {
 293                 strncpy( ifname, "unknown", IF_NAMESIZE );
 294         }
 295
 296         /* ToDo listening at */
 297         switch( li->type )
 298         {
 299                 case CEGW_RULE_CAN_ETH:
 300                         printf( "can@%-*s -> udp@%s:%hu\n", src_width, ifname, \
 301                                  inet_ntoa(li->ip), li->port );
 302                         break;
 303                 case CEGW_RULE_ETH_CAN:
 304                         dotaddr = inet_ntoa(li->ip);
 305                         tmp = src_width - strlen(dotaddr) - 1;
 306                         printf( "udp@%s:%-*hu -> can@%s\n", inet_ntoa(li->ip), \
 307                                  tmp, li->port, ifname );
 308                         break;
 309         }
 310 }
 311
 312 int main( int argc, char* argv[] )
 313 {
 314         int s;
 315         int tmp = 0;
 316         int cmd = 0;
 317         char* optstr;
 318         char opt;
 319         struct sockaddr_nl nladdr;
 320         int err = 0;
 321         struct cegw_nlmsg req;
 322         struct cegw_data d;
 323         char rxbuf[8192]; /* ToDo: /linux/netlink.h? */
 324         int rsize = 0;
 325         struct nlmsghdr* nlh;
 326         struct nlmsgerr* rte;
 327         struct rtattr* rta;
 328         int len;
 329         struct list_item li;
 330
 331         /**/
 332         int fd;
 333
 334         fd = open( "/dev/cegw", O_RDONLY );
 335         if( fd == -1 )
 336         {
 337                 fprintf( stderr, "error: could not open device file\n" );
 338                 return -1;
 339         }
 340
 341         ioctl( fd, CEGW_IOCTL_CAN_SOCK, 8 );
 342         close( fd );
 343         return 0;
 344
 345         memset( &d, 0, sizeof(d) );
 346
 347         struct option long_opt[] =
 348         {
 349                 { "add"   , 0, NULL, 'A' },
 350                 { "flush" , 0, NULL, 'F' },
 351                 { "list"  , 0, NULL, 'L' },
 352                 { "listen", 1, NULL, 'l' },
 353                 { 0, 0, 0, 0 }
 354         };
 355
 356         while( 1 )
 357         {
 358                 opt = getopt_long( argc, argv, "AFLl:s:d:", long_opt, NULL );
 359                 if( opt == -1 )
 360                         break;
 361
 362                 switch( opt )
 363                 {
 364                         case 'A':
 365                                 cmd |= CEGW_CMD_ADD;
 366                                 break;
 367                         case 'F':
 368                                 cmd |= CEGW_CMD_FLUSH;
 369                                 break;
 370                         case 'L':
 371                                 cmd |= CEGW_CMD_LIST;
 372                                 break;
 373                         case 'l':
 374                                 cmd |= CEGW_CMD_LISTEN;
 375                                 if( (optstr = read_iftype( optarg, &tmp )) == NULL )
 376                                 {
 377                                         perr( "'--listen'" );
 378                                         return -1;
 379                                 }
 380                                 if( tmp != IF_ETH_UDP )
 381                                 {
 382                                         perr( "'--listen' expects udp interface" );
 383                                         return -1;
 384                                 }
 385                                 if( read_addrport( optstr, &d.eth_listen_addr, &d.eth_listen_port ) )
 386                                 {
 387                                         perr( "'--listen'" );
 388                                         return -1;
 389                                 }
 390                                 break;
 391                         case 's':
 392                                 if( read_if( optarg, &d.src_if, &d ) != 0 )
 393                                 {
 394                                         perr( "'-s'" );
 395                                         return -1;
 396                                 }
 397                                 break;
 398                         case 'd':
 399                                 if( read_if( optarg, &d.dst_if, &d ) != 0 )
 400                                 {
 401                                         perr( "'-d'" );
 402                                         return -1;
 403                                 }
 404                                 break;
 405                         case '?':
 406                                 return -1;
 407                                 break;
 408                         default:
 409                                 perr( "unknown option" );
 410                                 return -1;
 411                                 break;
 412                 }
 413         }
 414
 415         /* prepare netlink message */
 416         req.nh.nlmsg_len   = NLMSG_LENGTH( sizeof(struct rtmsg) );
 417         //req.nh.nlmsg_type;
 418         req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
 419         req.nh.nlmsg_seq   = 0;
 420         req.nh.nlmsg_pid   = 0; /* ? */
 421
 422         memset( &req.rt, 0, sizeof(req.rt) );
 423         req.rt.rtm_family = AF_CAN;
 424
 425         switch( cmd )
 426         {
 427                 case 0:
 428                         perr( "command not specified" );
 429                         return -1;
 430                         break;
 431                 case CEGW_CMD_ADD:
 432                         if( cegw_add( &req, &d ) != 0 )
 433                         {
 434                                 perr( "'--add'" );
 435                                 return -1;
 436                         }
 437                         break;
 438                 case CEGW_CMD_FLUSH:
 439                         cegw_flush( &req, &d );
 440                         break;
 441                 case CEGW_CMD_LIST:
 442                         cegw_list( &req, &d );
 443                         break;
 444                 case CEGW_CMD_LISTEN:
 445                         cegw_listen( &req, &d );
 446                         break;
 447                 default:
 448                         perr( "command mismatch" );
 449                         break;
 450         }
 451
 452         /* send over netlink socket */
 453         s = socket( PF_NETLINK, SOCK_RAW, NETLINK_ROUTE ); /* chck */
 454
 455         memset( &nladdr, 0, sizeof(nladdr) );
 456         nladdr.nl_family = AF_NETLINK;
 457         nladdr.nl_pad = 0;
 458         nladdr.nl_pid = 0;
 459         nladdr.nl_groups = 0;
 460
 461         err = sendto( s, &req, req.nh.nlmsg_len, 0,
 462                       (struct sockaddr*)&nladdr, sizeof(nladdr) );
 463         if( err < 0 )
 464         {
 465                 perror( "netlink sendto" );
 466                 return -1;
 467         }
 468
 469         /* recv */
 470         rsize = recv( s, &rxbuf, sizeof(rxbuf), 0 );
 471         if( rsize < 0 )
 472         {
 473                 perr( "recv" );
 474                 return -1;
 475         }
 476         nlh = (struct nlmsghdr*)rxbuf;
 477
 478         if( nlh->nlmsg_type == NLMSG_ERROR )
 479         {
 480                 rte = (struct nlmsgerr*)NLMSG_DATA( nlh );
 481                 err = rte->error;
 482
 483                 if( err == 0  )
 484                 {
 485                         printf( "%s\n", strerror(abs(err)) );
 486                         return 0;
 487                 } else
 488                 {
 489                         printf( "netlink error: %s\n", strerror(abs(err)) );
 490                         return -1;
 491                 }
 492         }
 493
 494         if( cmd & CEGW_CMD_LIST )
 495         {
 496                 /* ToDo recv while */
 497                 printf( "%10ssource%20sdestination\n", "", "" );
 498                 while( 1 )
 499                 {
 500                         if( !NLMSG_OK( nlh, rsize ) )
 501                         {
 502                                 break;
 503                         }
 504                         if( nlh->nlmsg_type == NLMSG_DONE )
 505                         {
 506                                 break;
 507                         }
 508                         /* ToDo: NLMSG_ERR */
 509                         rta = NLMSG_DATA( nlh );
 510                         len = NLMSG_PAYLOAD( nlh, 0 );
 511                         for( ;RTA_OK(rta, len); rta = RTA_NEXT(rta,len) )
 512                         {
 513                                 switch( rta->rta_type )
 514                                 {
 515                                         case CEGW_TYPE:
 516                                                 li.type = *(int*)RTA_DATA(rta);
 517                                                 break;
 518                                         case CEGW_CAN_IFINDEX:
 519                                                 li.can = *(int*)RTA_DATA(rta);
 520                                                 break;
 521                                         case CEGW_ETH_IP:
 522                                                 li.ip = *(struct in_addr*)RTA_DATA(rta);
 523                                                 break;
 524                                         case CEGW_ETH_PORT:
 525                                                 li.port = *(unsigned short*)RTA_DATA(rta);
 526                                                 break;
 527                                         /* case CGW_ETH_PROTO */
 528                                 }
 529                         }
 530
 531                         print_list_item( &li );
 532
 533                         nlh = NLMSG_NEXT( nlh, rsize );
 534                 }
 535         }
 536
 537         return 0;
 538 }
 539