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