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 /**
 185  * read_if - reads interface from @in
 186  * Function analyzes @in for interface specification in format
 187  * <if>@<ip>:<port>, where <if> is can or udp, <ip> is address in dotted
 188  * format
 189  *
 190  * @param[in]  in string to search in
 191  * @param[out] iftype interface type (IF_CAN or IF_ETH_UDP)
 192  * @param[out] d ip and port is stored to @d
 193  */
 194 int read_if( char* in, int* iftype, struct cegw_data* d )
 195 {
 196         char* optstr = NULL;
 197
 198         if( (optstr = read_iftype( in, iftype )) == NULL )
 199         {
 200                 return -1;
 201         }
 202
 203         switch( *iftype )
 204         {
 205                 case IF_CAN:
 206                         d->can_ifidx = if_nametoindex( optstr );
 207                         if( d->can_ifidx == 0 )
 208                         {
 209                                 cegw_errno = CEGW_ERR_IF_CAN;
 210                                 return -1;
 211                         }
 212                         break;
 213                 case IF_ETH_UDP:
 214                         if( read_addrport( optstr, &d->eth_addr, &d->eth_port ) != 0 )
 215                         {
 216                                 return -1;
 217                         }
 218                         break;
 219                 default:
 220                         return -1;
 221                         break;
 222         }
 223
 224         return 0;
 225 }
 226
 227 inline static int cegw_add( struct cegw_nlmsg* req, struct cegw_data* d )
 228 {
 229         int gwtype = 0;
 230
 231         req->nh.nlmsg_type  = RTM_NEWROUTE;
 232         if( (d->src_if == 0 || d->dst_if == 0) )
 233         {
 234                 cegw_errno = CEGW_ERR_IF_UNSPEC;
 235                 return -cegw_errno;
 236         }
 237
 238         if( d->src_if == d->dst_if )
 239         {
 240                 cegw_errno = CEGW_ERR_IF_SAME;
 241                 return -cegw_errno;
 242         }
 243
 244         gwtype = (d->src_if == IF_CAN) ? CEGW_RULE_CAN_ETH : CEGW_RULE_ETH_CAN;
 245         addattr_l( &req->nh, sizeof(*req), CEGW_CAN_IFINDEX, &d->can_ifidx, sizeof(d->can_ifidx) );
 246
 247         switch( gwtype )
 248         {
 249                 case CEGW_RULE_CAN_ETH:
 250                         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_IP, &d->eth_addr, sizeof(d->eth_addr) );
 251                         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_PORT, &d->eth_port, sizeof(d->eth_port) );
 252                         break;
 253                 case CEGW_RULE_ETH_CAN:
 254                         break;
 255                 default:
 256                         break;
 257         }
 258
 259         addattr32( &req->nh, sizeof(*req), CEGW_CMD_INFO, gwtype );
 260
 261         return 0;
 262 }
 263
 264 inline static int cegw_listen( struct cegw_nlmsg* req, struct cegw_data* d )
 265 {
 266         req->nh.nlmsg_type = RTM_NEWROUTE;
 267         addattr32( &req->nh, sizeof(*req), CEGW_CMD_INFO, CEGW_LISTEN );
 268         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_IP, &d->eth_listen_addr, sizeof(d->eth_listen_addr) );
 269         addattr_l( &req->nh, sizeof(*req), CEGW_ETH_PORT, &d->eth_listen_port, sizeof(d->eth_listen_port) );
 270         printf( "listen at: %x, %hu\n", d->eth_listen_addr.s_addr, d->eth_listen_port );
 271
 272         return 0;
 273 }
 274
 275 inline static int cegw_list( struct cegw_nlmsg* req, struct cegw_data* d )
 276 {
 277         req->nh.nlmsg_type = RTM_GETROUTE;
 278         req->nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
 279
 280         return 0;
 281 }
 282
 283 inline static int cegw_flush( struct cegw_nlmsg* req, struct cegw_data* d )
 284 {
 285         addattr32( &req->nh, sizeof(*req), CEGW_CMD_INFO, CEGW_FLUSH );
 286         req->nh.nlmsg_type  = RTM_DELROUTE;
 287         return 0;
 288 }
 289
 290 void print_list_item( struct list_item* li )
 291 {
 292         char ifname[IF_NAMESIZE];
 293         const char src_width = 21;
 294         char* dotaddr;
 295         int tmp;
 296
 297         if( if_indextoname( li->can, ifname ) == NULL )
 298         {
 299                 strncpy( ifname, "unknown", IF_NAMESIZE );
 300         }
 301
 302         /* ToDo listening at */
 303         switch( li->type )
 304         {
 305                 case CEGW_RULE_CAN_ETH:
 306                         printf( "can@%-*s -> udp@%s:%hu\n", src_width, ifname, \
 307                                  inet_ntoa(li->ip), li->port );
 308                         break;
 309                 case CEGW_RULE_ETH_CAN:
 310                         dotaddr = inet_ntoa(li->ip);
 311                         tmp = src_width - strlen(dotaddr) - 1;
 312                         printf( "udp@%s:%-*hu -> can@%s\n", inet_ntoa(li->ip), \
 313                                  tmp, li->port, ifname );
 314                         break;
 315         }
 316 }
 317
 318 int main( int argc, char* argv[] )
 319 {
 320         int s;
 321         int tmp = 0;
 322         int cmd = 0;
 323         char* optstr;
 324         char opt;
 325         struct sockaddr_nl nladdr;
 326         int err = 0;
 327         struct cegw_nlmsg req;
 328         struct cegw_data d;
 329         char rxbuf[8192]; /* ToDo: /linux/netlink.h? */
 330         int rsize = 0;
 331         struct nlmsghdr* nlh;
 332         struct nlmsgerr* rte;
 333         struct rtattr* rta;
 334         int len;
 335         struct list_item li;
 336
 337         memset( &d, 0, sizeof(d) );
 338
 339         struct option long_opt[] =
 340         {
 341                 { "add"   , 0, NULL, 'A' },
 342                 { "flush" , 0, NULL, 'F' },
 343                 { "list"  , 0, NULL, 'L' },
 344                 { "listen", 1, NULL, 'l' },
 345                 { 0, 0, 0, 0 }
 346         };
 347
 348         while( 1 )
 349         {
 350                 opt = getopt_long( argc, argv, "AFLl:s:d:", long_opt, NULL );
 351                 if( opt == -1 )
 352                         break;
 353
 354                 switch( opt )
 355                 {
 356                         case 'A':
 357                                 cmd |= CEGW_CMD_ADD;
 358                                 break;
 359                         case 'F':
 360                                 cmd |= CEGW_CMD_FLUSH;
 361                                 break;
 362                         case 'L':
 363                                 cmd |= CEGW_CMD_LIST;
 364                                 break;
 365                         case 'l':
 366                                 cmd |= CEGW_CMD_LISTEN;
 367                                 if( (optstr = read_iftype( optarg, &tmp )) == NULL )
 368                                 {
 369                                         perr( "'--listen'" );
 370                                         return -1;
 371                                 }
 372                                 if( tmp != IF_ETH_UDP )
 373                                 {
 374                                         perr( "'--listen' expects udp interface" );
 375                                         return -1;
 376                                 }
 377                                 if( read_addrport( optstr, &d.eth_listen_addr, &d.eth_listen_port ) )
 378                                 {
 379                                         perr( "'--listen'" );
 380                                         return -1;
 381                                 }
 382                                 break;
 383                         case 's':
 384                                 if( read_if( optarg, &d.src_if, &d ) != 0 )
 385                                 {
 386                                         perr( "'-s'" );
 387                                         return -1;
 388                                 }
 389                                 break;
 390                         case 'd':
 391                                 if( read_if( optarg, &d.dst_if, &d ) != 0 )
 392                                 {
 393                                         perr( "'-d'" );
 394                                         return -1;
 395                                 }
 396                                 break;
 397                         case '?':
 398                                 return -1;
 399                                 break;
 400                         default:
 401                                 perr( "unknown option" );
 402                                 return -1;
 403                                 break;
 404                 }
 405         }
 406
 407         /* prepare netlink message */
 408         req.nh.nlmsg_len   = NLMSG_LENGTH( sizeof(struct rtmsg) );
 409         //req.nh.nlmsg_type;
 410         req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
 411         req.nh.nlmsg_seq   = 0;
 412         req.nh.nlmsg_pid   = 0; /* ? */
 413
 414         memset( &req.rt, 0, sizeof(req.rt) );
 415         req.rt.rtm_family = AF_CAN;
 416
 417         switch( cmd )
 418         {
 419                 case 0:
 420                         perr( "command not specified" );
 421                         return -1;
 422                         break;
 423                 case CEGW_CMD_ADD:
 424                         if( cegw_add( &req, &d ) != 0 )
 425                         {
 426                                 perr( "'--add'" );
 427                                 return -1;
 428                         }
 429                         break;
 430                 case CEGW_CMD_FLUSH:
 431                         cegw_flush( &req, &d );
 432                         break;
 433                 case CEGW_CMD_LIST:
 434                         cegw_list( &req, &d );
 435                         break;
 436                 case CEGW_CMD_LISTEN:
 437                         cegw_listen( &req, &d );
 438                         break;
 439                 default:
 440                         perr( "command mismatch" );
 441                         break;
 442         }
 443
 444         /* send over netlink socket */
 445         s = socket( PF_NETLINK, SOCK_RAW, NETLINK_ROUTE ); /* chck */
 446
 447         memset( &nladdr, 0, sizeof(nladdr) );
 448         nladdr.nl_family = AF_NETLINK;
 449         nladdr.nl_pad = 0;
 450         nladdr.nl_pid = 0;
 451         nladdr.nl_groups = 0;
 452
 453         err = sendto( s, &req, req.nh.nlmsg_len, 0,
 454                       (struct sockaddr*)&nladdr, sizeof(nladdr) );
 455         if( err < 0 )
 456         {
 457                 perror( "netlink sendto" );
 458                 return err;
 459         }
 460
 461         /* recv */
 462         rsize = recv( s, &rxbuf, sizeof(rxbuf), 0 );
 463         printf( "recv size=%d\n", rsize );
 464         if( rsize < 0 )
 465         {
 466                 perr( "recv" );
 467                 return -1;
 468         }
 469         nlh = (struct nlmsghdr*)rxbuf;
 470
 471         if( cmd & CEGW_CMD_LIST )
 472         {
 473                 printf( "recv nlmsg_type=%d\n", nlh->nlmsg_type );
 474                 if( nlh->nlmsg_type == NLMSG_ERROR )
 475                 {
 476                         struct nlmsgerr* nlerr = NLMSG_DATA( nlh );
 477                         int err = nlerr->error;
 478                         printf( "nlerror: %d,%s\n", err, strerror(abs(err)) );
 479                 }
 480                 /* ToDo recv while */
 481                 printf( "%10ssource%20sdestination\n", "", "" );
 482                 while( 1 )
 483                 {
 484                         if( !NLMSG_OK( nlh, rsize ) )
 485                         {
 486                                 puts( "NLMSG_OK\n" );
 487                                 break;
 488                         }
 489                         if( nlh->nlmsg_type == NLMSG_DONE )
 490                         {
 491                                 puts( "NLMSG_DONE" );
 492                                 break;
 493                         }
 494                         /* ToDo: NLMSG_ERR */
 495
 496                         rta = NLMSG_DATA( nlh );
 497                         //rta = (struct rtattr*)( ((char *)rtm) + NLMSG_ALIGN(sizeof(struct rtmsg)) );
 498                         len = NLMSG_PAYLOAD( nlh, 0 );
 499                         for( ;RTA_OK(rta, len); rta = RTA_NEXT(rta,len) )
 500                         {
 501                                 switch( rta->rta_type )
 502                                 {
 503                                         case CEGW_TYPE:
 504                                                 li.type = *(int*)RTA_DATA(rta);
 505                                                 break;
 506                                         case CEGW_CAN_IFINDEX:
 507                                                 li.can = *(int*)RTA_DATA(rta);
 508                                                 break;
 509                                         case CEGW_ETH_IP:
 510                                                 li.ip = *(struct in_addr*)RTA_DATA(rta);
 511                                                 break;
 512                                         case CEGW_ETH_PORT:
 513                                                 li.port = *(unsigned short*)RTA_DATA(rta);
 514                                                 break;
 515                                         /* case CGW_ETH_PROTO */
 516                                 }
 517                         }
 518
 519                         print_list_item( &li );
 520
 521                         nlh = NLMSG_NEXT( nlh, rsize );
 522                 }
 523         } else
 524         {
 525                 if( nlh->nlmsg_type != NLMSG_ERROR )
 526                 {
 527                         fprintf( stderr, "error: unexpected netlink answer=%d\n", nlh->nlmsg_type );
 528                         return -1;
 529                 }
 530                 rte = (struct nlmsgerr*)NLMSG_DATA( nlh );
 531                 err = rte->error;
 532                 if( err < 0 )
 533                         fprintf( stderr, "error: netlink(%d); %s\n", err, strerror(abs(err)) );
 534         }
 535
 536         return 0;
 537 }
 538