src/net/udp.c

   1 #include <stdint.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <assert.h>
   5 #include <byteswap.h>
   6 #include <errno.h>
   7 #include <gpxe/tcpip.h>
   8 #include <gpxe/iobuf.h>
   9 #include <gpxe/xfer.h>
  10 #include <gpxe/open.h>
  11 #include <gpxe/uri.h>
  12 #include <gpxe/udp.h>
  13
  14 /** @file
  15  *
  16  * UDP protocol
  17  */
  18
  19 /**
  20  * A UDP connection
  21  *
  22  */
  23 struct udp_connection {
  24         /** Reference counter */
  25         struct refcnt refcnt;
  26         /** List of UDP connections */
  27         struct list_head list;
  28
  29         /** Data transfer interface */
  30         struct xfer_interface xfer;
  31
  32         /** Remote socket address */
  33         struct sockaddr_tcpip peer;
  34         /** Local port on which the connection receives packets */
  35         unsigned int local_port;
  36 };
  37
  38 /**
  39  * List of registered UDP connections
  40  */
  41 static LIST_HEAD ( udp_conns );
  42
  43 /* Forward declatations */
  44 static struct xfer_interface_operations udp_xfer_operations;
  45 struct tcpip_protocol udp_protocol;
  46
  47 /**
  48  * Bind UDP connection to local port
  49  *
  50  * @v udp               UDP connection
  51  * @v port              Local port, in network byte order, or zero
  52  * @ret rc              Return status code
  53  *
  54  * Opens the UDP connection and binds to a local port.  If no local
  55  * port is specified, the first available port will be used.
  56  */
  57 static int udp_bind ( struct udp_connection *udp, unsigned int port ) {
  58         struct udp_connection *existing;
  59         static uint16_t try_port = 1024;
  60
  61         /* If no port specified, find the first available port */
  62         if ( ! port ) {
  63                 for ( ; try_port ; try_port++ ) {
  64                         if ( try_port < 1024 )
  65                                 continue;
  66                         if ( udp_bind ( udp, htons ( try_port ) ) == 0 )
  67                                 return 0;
  68                 }
  69                 return -EADDRINUSE;
  70         }
  71
  72         /* Attempt bind to local port */
  73         list_for_each_entry ( existing, &udp_conns, list ) {
  74                 if ( existing->local_port == port ) {
  75                         DBGC ( udp, "UDP %p could not bind: port %d in use\n",
  76                                udp, ntohs ( port ) );
  77                         return -EADDRINUSE;
  78                 }
  79         }
  80         udp->local_port = port;
  81
  82         /* Add to UDP connection list */
  83         DBGC ( udp, "UDP %p bound to port %d\n", udp, ntohs ( port ) );
  84
  85         return 0;
  86 }
  87
  88 /**
  89  * Open a UDP connection
  90  *
  91  * @v xfer              Data transfer interface
  92  * @v peer              Peer socket address
  93  * @v local             Local socket address, or NULL
  94  * @v promisc           Socket is promiscuous
  95  * @ret rc              Return status code
  96  */
  97 static int udp_open_common ( struct xfer_interface *xfer,
  98                              struct sockaddr *peer, struct sockaddr *local,
  99                              int promisc ) {
 100         struct sockaddr_tcpip *st_peer = ( struct sockaddr_tcpip * ) peer;
 101         struct sockaddr_tcpip *st_local = ( struct sockaddr_tcpip * ) local;
 102         struct udp_connection *udp;
 103         unsigned int bind_port;
 104         int rc;
 105
 106         /* Allocate and initialise structure */
 107         udp = zalloc ( sizeof ( *udp ) );
 108         if ( ! udp )
 109                 return -ENOMEM;
 110         DBGC ( udp, "UDP %p allocated\n", udp );
 111         xfer_init ( &udp->xfer, &udp_xfer_operations, &udp->refcnt );
 112         memcpy ( &udp->peer, st_peer, sizeof ( udp->peer ) );
 113
 114         /* Bind to local port */
 115         if ( ! promisc ) {
 116                 bind_port = ( st_local ? st_local->st_port : 0 );
 117                 if ( ( rc = udp_bind ( udp, bind_port ) ) != 0 )
 118                         goto err;
 119         }
 120
 121         /* Attach parent interface, transfer reference to connection
 122          * list and return
 123          */
 124         xfer_plug_plug ( &udp->xfer, xfer );
 125         list_add ( &udp->list, &udp_conns );
 126         return 0;
 127
 128  err:
 129         ref_put ( &udp->refcnt );
 130         return rc;
 131 }
 132
 133 /**
 134  * Open a UDP connection
 135  *
 136  * @v xfer              Data transfer interface
 137  * @v peer              Peer socket address
 138  * @v local             Local socket address, or NULL
 139  * @ret rc              Return status code
 140  */
 141 int udp_open ( struct xfer_interface *xfer, struct sockaddr *peer,
 142                struct sockaddr *local ) {
 143         return udp_open_common ( xfer, peer, local, 0 );
 144 }
 145
 146 /**
 147  * Open a promiscuous UDP connection
 148  *
 149  * @v xfer              Data transfer interface
 150  * @ret rc              Return status code
 151  *
 152  * Promiscuous UDP connections are required in order to support the
 153  * PXE API.
 154  */
 155 int udp_open_promisc ( struct xfer_interface *xfer ) {
 156         return udp_open_common ( xfer, NULL, NULL, 1 );
 157 }
 158
 159 /**
 160  * Close a UDP connection
 161  *
 162  * @v udp               UDP connection
 163  * @v rc                Reason for close
 164  */
 165 static void udp_close ( struct udp_connection *udp, int rc ) {
 166
 167         /* Close data transfer interface */
 168         xfer_nullify ( &udp->xfer );
 169         xfer_close ( &udp->xfer, rc );
 170
 171         /* Remove from list of connections and drop list's reference */
 172         list_del ( &udp->list );
 173         ref_put ( &udp->refcnt );
 174
 175         DBGC ( udp, "UDP %p closed\n", udp );
 176 }
 177
 178 /**
 179  * Transmit data via a UDP connection to a specified address
 180  *
 181  * @v udp               UDP connection
 182  * @v iobuf             I/O buffer
 183  * @v src_port          Source port, or 0 to use default
 184  * @v dest              Destination address, or NULL to use default
 185  * @v netdev            Network device, or NULL to use default
 186  * @ret rc              Return status code
 187  */
 188 static int udp_tx ( struct udp_connection *udp, struct io_buffer *iobuf,
 189                     unsigned int src_port, struct sockaddr_tcpip *dest,
 190                     struct net_device *netdev ) {
 191         struct udp_header *udphdr;
 192         size_t len;
 193         int rc;
 194
 195         /* Check we can accommodate the header */
 196         if ( ( rc = iob_ensure_headroom ( iobuf, UDP_MAX_HLEN ) ) != 0 ) {
 197                 free_iob ( iobuf );
 198                 return rc;
 199         }
 200
 201         /* Fill in default values if not explicitly provided */
 202         if ( ! src_port )
 203                 src_port = udp->local_port;
 204         if ( ! dest )
 205                 dest = &udp->peer;
 206
 207         /* Add the UDP header */
 208         udphdr = iob_push ( iobuf, sizeof ( *udphdr ) );
 209         len = iob_len ( iobuf );
 210         udphdr->dest = dest->st_port;
 211         udphdr->src = src_port;
 212         udphdr->len = htons ( len );
 213         udphdr->chksum = 0;
 214         udphdr->chksum = tcpip_chksum ( udphdr, len );
 215
 216         /* Dump debugging information */
 217         DBGC ( udp, "UDP %p TX %d->%d len %zd\n", udp,
 218                ntohs ( udphdr->src ), ntohs ( udphdr->dest ),
 219                ntohs ( udphdr->len ) );
 220
 221         /* Send it to the next layer for processing */
 222         if ( ( rc = tcpip_tx ( iobuf, &udp_protocol, dest, netdev,
 223                                &udphdr->chksum ) ) != 0 ) {
 224                 DBGC ( udp, "UDP %p could not transmit packet: %s\n",
 225                        udp, strerror ( rc ) );
 226                 return rc;
 227         }
 228
 229         return 0;
 230 }
 231
 232 /**
 233  * Identify UDP connection by local port number
 234  *
 235  * @v local_port        Local port (in network-endian order)
 236  * @ret udp             UDP connection, or NULL
 237  */
 238 static struct udp_connection * udp_demux ( unsigned int local_port ) {
 239         struct udp_connection *udp;
 240
 241         list_for_each_entry ( udp, &udp_conns, list ) {
 242                 if ( ( udp->local_port == local_port ) ||
 243                      ( udp->local_port == 0 ) ) {
 244                         return udp;
 245                 }
 246         }
 247         return NULL;
 248 }
 249
 250 /**
 251  * Process a received packet
 252  *
 253  * @v iobuf             I/O buffer
 254  * @v st_src            Partially-filled source address
 255  * @v st_dest           Partially-filled destination address
 256  * @v pshdr_csum        Pseudo-header checksum
 257  * @ret rc              Return status code
 258  */
 259 static int udp_rx ( struct io_buffer *iobuf, struct sockaddr_tcpip *st_src,
 260                     struct sockaddr_tcpip *st_dest, uint16_t pshdr_csum ) {
 261         struct udp_header *udphdr = iobuf->data;
 262         struct udp_connection *udp;
 263         struct xfer_metadata meta;
 264         size_t ulen;
 265         unsigned int csum;
 266         int rc = 0;
 267
 268         /* Sanity check packet */
 269         if ( iob_len ( iobuf ) < sizeof ( *udphdr ) ) {
 270                 DBG ( "UDP packet too short at %d bytes (min %d bytes)\n",
 271                       iob_len ( iobuf ), sizeof ( *udphdr ) );
 272
 273                 rc = -EINVAL;
 274                 goto done;
 275         }
 276         ulen = ntohs ( udphdr->len );
 277         if ( ulen < sizeof ( *udphdr ) ) {
 278                 DBG ( "UDP length too short at %d bytes "
 279                       "(header is %d bytes)\n", ulen, sizeof ( *udphdr ) );
 280                 rc = -EINVAL;
 281                 goto done;
 282         }
 283         if ( ulen > iob_len ( iobuf ) ) {
 284                 DBG ( "UDP length too long at %d bytes (packet is %d bytes)\n",
 285                       ulen, iob_len ( iobuf ) );
 286                 rc = -EINVAL;
 287                 goto done;
 288         }
 289         if ( udphdr->chksum ) {
 290                 csum = tcpip_continue_chksum ( pshdr_csum, iobuf->data, ulen );
 291                 if ( csum != 0 ) {
 292                         DBG ( "UDP checksum incorrect (is %04x including "
 293                               "checksum field, should be 0000)\n", csum );
 294                         rc = -EINVAL;
 295                         goto done;
 296                 }
 297         }
 298
 299         /* Parse parameters from header and strip header */
 300         st_src->st_port = udphdr->src;
 301         st_dest->st_port = udphdr->dest;
 302         udp = udp_demux ( udphdr->dest );
 303         iob_unput ( iobuf, ( iob_len ( iobuf ) - ulen ) );
 304         iob_pull ( iobuf, sizeof ( *udphdr ) );
 305
 306         /* Dump debugging information */
 307         DBGC ( udp, "UDP %p RX %d<-%d len %zd\n", udp,
 308                ntohs ( udphdr->dest ), ntohs ( udphdr->src ), ulen );
 309
 310         /* Ignore if no matching connection found */
 311         if ( ! udp ) {
 312                 DBG ( "No UDP connection listening on port %d\n",
 313                       ntohs ( udphdr->dest ) );
 314                 rc = -ENOTCONN;
 315                 goto done;
 316         }
 317
 318         /* Pass data to application */
 319         memset ( &meta, 0, sizeof ( meta ) );
 320         meta.src = ( struct sockaddr * ) st_src;
 321         meta.dest = ( struct sockaddr * ) st_dest;
 322         rc = xfer_deliver_iob_meta ( &udp->xfer, iobuf, &meta );
 323         iobuf = NULL;
 324
 325  done:
 326         free_iob ( iobuf );
 327         return rc;
 328 }
 329
 330 struct tcpip_protocol udp_protocol __tcpip_protocol = {
 331         .name = "UDP",
 332         .rx = udp_rx,
 333         .tcpip_proto = IP_UDP,
 334 };
 335
 336 /***************************************************************************
 337  *
 338  * Data transfer interface
 339  *
 340  ***************************************************************************
 341  */
 342
 343 /**
 344  * Close interface
 345  *
 346  * @v xfer              Data transfer interface
 347  * @v rc                Reason for close
 348  */
 349 static void udp_xfer_close ( struct xfer_interface *xfer, int rc ) {
 350         struct udp_connection *udp =
 351                 container_of ( xfer, struct udp_connection, xfer );
 352
 353         /* Close connection */
 354         udp_close ( udp, rc );
 355 }
 356
 357 /**
 358  * Allocate I/O buffer for UDP
 359  *
 360  * @v xfer              Data transfer interface
 361  * @v len               Payload size
 362  * @ret iobuf           I/O buffer, or NULL
 363  */
 364 static struct io_buffer * udp_alloc_iob ( struct xfer_interface *xfer,
 365                                           size_t len ) {
 366         struct udp_connection *udp =
 367                 container_of ( xfer, struct udp_connection, xfer );
 368         struct io_buffer *iobuf;
 369
 370         iobuf = alloc_iob ( UDP_MAX_HLEN + len );
 371         if ( ! iobuf ) {
 372                 DBGC ( udp, "UDP %p cannot allocate buffer of length %d\n",
 373                        udp, len );
 374                 return NULL;
 375         }
 376         iob_reserve ( iobuf, UDP_MAX_HLEN );
 377         return iobuf;
 378 }
 379
 380 /**
 381  * Deliver datagram as I/O buffer
 382  *
 383  * @v xfer              Data transfer interface
 384  * @v iobuf             Datagram I/O buffer
 385  * @v meta              Data transfer metadata, or NULL
 386  * @ret rc              Return status code
 387  */
 388 static int udp_xfer_deliver_iob ( struct xfer_interface *xfer,
 389                                   struct io_buffer *iobuf,
 390                                   struct xfer_metadata *meta ) {
 391         struct udp_connection *udp =
 392                 container_of ( xfer, struct udp_connection, xfer );
 393         struct sockaddr_tcpip *src;
 394         struct sockaddr_tcpip *dest = NULL;
 395         struct net_device *netdev = NULL;
 396         unsigned int src_port = 0;
 397
 398         /* Apply xfer metadata */
 399         if ( meta ) {
 400                 src = ( struct sockaddr_tcpip * ) meta->src;
 401                 if ( src )
 402                         src_port = src->st_port;
 403                 dest = ( struct sockaddr_tcpip * ) meta->dest;
 404                 netdev = meta->netdev;
 405         }
 406
 407         /* Transmit data, if possible */
 408         udp_tx ( udp, iobuf, src_port, dest, netdev );
 409
 410         return 0;
 411 }
 412
 413 /** UDP data transfer interface operations */
 414 static struct xfer_interface_operations udp_xfer_operations = {
 415         .close          = udp_xfer_close,
 416         .vredirect      = ignore_xfer_vredirect,
 417         .seek           = ignore_xfer_seek,
 418         .window         = unlimited_xfer_window,
 419         .alloc_iob      = udp_alloc_iob,
 420         .deliver_iob    = udp_xfer_deliver_iob,
 421         .deliver_raw    = xfer_deliver_as_iob,
 422 };
 423
 424 /***************************************************************************
 425  *
 426  * Openers
 427  *
 428  ***************************************************************************
 429  */
 430
 431 /** UDP socket opener */
 432 struct socket_opener udp_socket_opener __socket_opener = {
 433         .semantics      = SOCK_DGRAM,
 434         .family         = AF_INET,
 435         .open           = udp_open,
 436 };
 437
 438 char UDP_SOCK_DGRAM[1];
 439
 440 /**
 441  * Open UDP URI
 442  *
 443  * @v xfer              Data transfer interface
 444  * @v uri               URI
 445  * @ret rc              Return status code
 446  */
 447 static int udp_open_uri ( struct xfer_interface *xfer, struct uri *uri ) {
 448         struct sockaddr_tcpip peer;
 449
 450         /* Sanity check */
 451         if ( ! uri->host )
 452                 return -EINVAL;
 453
 454         memset ( &peer, 0, sizeof ( peer ) );
 455         peer.st_port = htons ( uri_port ( uri, 0 ) );
 456         return xfer_open_named_socket ( xfer, SOCK_DGRAM,
 457                                         ( struct sockaddr * ) &peer,
 458                                         uri->host, NULL );
 459 }
 460
 461 /** UDP URI opener */
 462 struct uri_opener udp_uri_opener __uri_opener = {
 463         .scheme         = "udp",
 464         .open           = udp_open_uri,
 465 };