src/network/udp.c

   1 /*****************************************************************************
   2  * udp.c:
   3  *****************************************************************************
   4  * Copyright (C) 2004-2006 the VideoLAN team
   5  * Copyright © 2006-2007 Rémi Denis-Courmont
   6  *
   7  * $Id$
   8  *
   9  * Authors: Laurent Aimar <fenrir@videolan.org>
  10  *          Rémi Denis-Courmont <rem # videolan.org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30 #include <vlc/vlc.h>
  31
  32 #include <errno.h>
  33
  34 #ifdef HAVE_SYS_TIME_H
  35 #    include <sys/time.h>
  36 #endif
  37
  38 #include <vlc_network.h>
  39
  40 #ifdef WIN32
  41 #   if defined(UNDER_CE)
  42 #       undef IP_MULTICAST_TTL
  43 #       define IP_MULTICAST_TTL 3
  44 #       undef IP_ADD_MEMBERSHIP
  45 #       define IP_ADD_MEMBERSHIP 5
  46 #   endif
  47 #   define EAFNOSUPPORT WSAEAFNOSUPPORT
  48 #   define if_nametoindex( str ) atoi( str )
  49 #else
  50 #   include <unistd.h>
  51 #   ifdef HAVE_NET_IF_H
  52 #       include <net/if.h>
  53 #   endif
  54 #endif
  55
  56 #ifdef HAVE_LINUX_DCCP_H
  57 # include <linux/dccp.h>
  58 # ifndef SOCK_DCCP /* provisional API */
  59 #  define SOCK_DCCP 6
  60 # endif
  61 #endif
  62
  63 #ifndef SOL_IP
  64 # define SOL_IP IPPROTO_IP
  65 #endif
  66 #ifndef SOL_IPV6
  67 # define SOL_IPV6 IPPROTO_IPV6
  68 #endif
  69 #ifndef IPPROTO_IPV6
  70 # define IPPROTO_IPV6 41 /* IANA */
  71 #endif
  72 #ifndef SOL_DCCP
  73 # define SOL_DCCP IPPROTO_DCCP
  74 #endif
  75 #ifndef IPPROTO_DCCP
  76 # define IPPROTO_DCCP 33 /* IANA */
  77 #endif
  78 #ifndef SOL_UDPLITE
  79 # define SOL_UDPLITE IPPROTO_UDPLITE
  80 #endif
  81 #ifndef IPPROTO_UDPLITE
  82 # define IPPROTO_UDPLITE 136 /* IANA */
  83 #endif
  84
  85 #if defined (HAVE_NETINET_UDPLITE_H)
  86 # include <netinet/udplite.h>
  87 #elif defined (__linux__)
  88 /* still missing from glibc 2.6 */
  89 # define UDPLITE_SEND_CSCOV     10
  90 # define UDPLITE_RECV_CSCOV     11
  91 #endif
  92
  93 extern int net_Socket( vlc_object_t *p_this, int i_family, int i_socktype,
  94                        int i_protocol );
  95
  96 static int net_ListenSingle (vlc_object_t *obj, const char *host, int port,
  97                              int family, int protocol)
  98 {
  99     struct addrinfo hints, *res;
 100
 101     memset (&hints, 0, sizeof( hints ));
 102     hints.ai_family = family;
 103     hints.ai_socktype = SOCK_DGRAM;
 104     hints.ai_flags = AI_PASSIVE;
 105
 106     if (host && !*host)
 107         host = NULL;
 108
 109     msg_Dbg (obj, "net: opening %s datagram port %d", host ?: "any", port);
 110
 111     int val = vlc_getaddrinfo (obj, host, port, &hints, &res);
 112     if (val)
 113     {
 114         msg_Err (obj, "Cannot resolve %s port %d : %s", host, port,
 115                  vlc_gai_strerror (val));
 116         return -1;
 117     }
 118
 119     val = -1;
 120
 121     for (const struct addrinfo *ptr = res; ptr != NULL; ptr = ptr->ai_next)
 122     {
 123         int fd = net_Socket (obj, ptr->ai_family, ptr->ai_socktype,
 124                              protocol ?: ptr->ai_protocol);
 125         if (fd == -1)
 126         {
 127             msg_Dbg (obj, "socket error: %m");
 128             continue;
 129         }
 130
 131         if (ptr->ai_next != NULL)
 132         {
 133 #ifdef IPV6_V6ONLY
 134             if ((ptr->ai_family != AF_INET6)
 135              || setsockopt (fd, SOL_IPV6, IPV6_V6ONLY, &(int){ 0 },
 136                             sizeof (int)))
 137 #endif
 138             {
 139                 msg_Err (obj, "Multiple network protocols present");
 140                 msg_Err (obj, "Please select network protocol manually");
 141             }
 142         }
 143
 144         /* Bind the socket */
 145 #if defined (WIN32) || defined (UNDER_CE)
 146         if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 147          && (sizeof (struct sockaddr_storage) >= ptr->ai_addrlen))
 148         {
 149             struct sockaddr_in6 dumb =
 150             {
 151                 .sin6_family = ptr->ai_addr->sa_family,
 152                 .sin6_port =  ((struct sockaddr_in *)(ptr->ai_addr))->sin_port
 153             };
 154             bind (fd, (struct sockaddr *)&dumb, ptr->ai_addrlen);
 155         }
 156         else
 157 #endif
 158         if (bind (fd, ptr->ai_addr, ptr->ai_addrlen))
 159         {
 160             msg_Err (obj, "socket bind error (%m)");
 161             net_Close (fd);
 162             continue;
 163         }
 164
 165         if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 166          && net_Subscribe (obj, fd, ptr->ai_addr, ptr->ai_addrlen))
 167         {
 168             net_Close (fd);
 169             continue;
 170         }
 171
 172         val = fd;
 173         break;
 174     }
 175
 176     vlc_freeaddrinfo (res);
 177     return val;
 178 }
 179
 180
 181 static int net_SetMcastHopLimit( vlc_object_t *p_this,
 182                                  int fd, int family, int hlim )
 183 {
 184     int proto, cmd;
 185
 186     /* There is some confusion in the world whether IP_MULTICAST_TTL
 187      * takes a byte or an int as an argument.
 188      * BSD seems to indicate byte so we are going with that and use
 189      * int as a fallback to be safe */
 190     switch( family )
 191     {
 192 #ifdef IP_MULTICAST_TTL
 193         case AF_INET:
 194             proto = SOL_IP;
 195             cmd = IP_MULTICAST_TTL;
 196             break;
 197 #endif
 198
 199 #ifdef IPV6_MULTICAST_HOPS
 200         case AF_INET6:
 201             proto = SOL_IPV6;
 202             cmd = IPV6_MULTICAST_HOPS;
 203             break;
 204 #endif
 205
 206         default:
 207             errno = EAFNOSUPPORT;
 208             msg_Warn( p_this, "%m" );
 209             return VLC_EGENERIC;
 210     }
 211
 212     if( setsockopt( fd, proto, cmd, &hlim, sizeof( hlim ) ) < 0 )
 213     {
 214         /* BSD compatibility */
 215         unsigned char buf;
 216
 217         buf = (unsigned char)(( hlim > 255 ) ? 255 : hlim);
 218         if( setsockopt( fd, proto, cmd, &buf, sizeof( buf ) ) )
 219             return VLC_EGENERIC;
 220     }
 221
 222     return VLC_SUCCESS;
 223 }
 224
 225
 226 static int net_SetMcastOutIface (int fd, int family, int scope)
 227 {
 228     switch (family)
 229     {
 230 #ifdef IPV6_MULTICAST_IF
 231         case AF_INET6:
 232             return setsockopt (fd, SOL_IPV6, IPV6_MULTICAST_IF,
 233                                &scope, sizeof (scope));
 234 #endif
 235
 236 #ifdef __linux__
 237         case AF_INET:
 238         {
 239             struct ip_mreqn req = { .imr_ifindex = scope };
 240
 241             return setsockopt (fd, SOL_IP, IP_MULTICAST_IF, &req,
 242                                sizeof (req));
 243         }
 244 #endif
 245     }
 246
 247     errno = EAFNOSUPPORT;
 248     return -1;
 249 }
 250
 251
 252 static inline int net_SetMcastOutIPv4 (int fd, struct in_addr ipv4)
 253 {
 254 #ifdef IP_MULTICAST_IF
 255     return setsockopt( fd, SOL_IP, IP_MULTICAST_IF, &ipv4, sizeof (ipv4));
 256 #else
 257     errno = EAFNOSUPPORT;
 258     return -1;
 259 #endif
 260 }
 261
 262
 263 static int net_SetMcastOut (vlc_object_t *p_this, int fd, int family,
 264                             const char *iface, const char *addr)
 265 {
 266     if (iface != NULL)
 267     {
 268         int scope = if_nametoindex (iface);
 269         if (scope == 0)
 270         {
 271             msg_Err (p_this, "invalid multicast interface: %s", iface);
 272             return -1;
 273         }
 274
 275         if (net_SetMcastOutIface (fd, family, scope) == 0)
 276             return 0;
 277
 278         msg_Err (p_this, "%s: %m", iface);
 279     }
 280
 281     if (addr != NULL)
 282     {
 283         if (family == AF_INET)
 284         {
 285             struct in_addr ipv4;
 286             if (inet_pton (AF_INET, addr, &ipv4) <= 0)
 287             {
 288                 msg_Err (p_this, "invalid IPv4 address for multicast: %s",
 289                          addr);
 290                 return -1;
 291             }
 292
 293             if (net_SetMcastOutIPv4 (fd, ipv4) == 0)
 294                 return 0;
 295
 296             msg_Err (p_this, "%s: %m", addr);
 297         }
 298     }
 299
 300     return -1;
 301 }
 302
 303
 304 /**
 305  * Old-style any-source multicast join.
 306  * In use on Windows XP/2003 and older.
 307  */
 308 static int
 309 net_IPv4Join (vlc_object_t *obj, int fd,
 310               const struct sockaddr_in *src, const struct sockaddr_in *grp)
 311 {
 312 #ifdef IP_ADD_MEMBERSHIP
 313     union
 314     {
 315         struct ip_mreq gr4;
 316 # ifdef IP_ADD_SOURCE_MEMBERSHIP
 317         struct ip_mreq_source gsr4;
 318 # endif
 319     } opt;
 320     int cmd;
 321     struct in_addr id = { .s_addr = INADDR_ANY };
 322     socklen_t optlen;
 323
 324     /* Multicast interface IPv4 address */
 325     char *iface = var_CreateGetNonEmptyString (obj, "miface-addr");
 326     if ((iface != NULL)
 327      && (inet_pton (AF_INET, iface, &id) <= 0))
 328     {
 329         msg_Err (obj, "invalid multicast interface address %s", iface);
 330         free (iface);
 331         goto error;
 332     }
 333     free (iface);
 334
 335     memset (&opt, 0, sizeof (opt));
 336     if (src != NULL)
 337     {
 338 # ifdef IP_ADD_SOURCE_MEMBERSHIP
 339         cmd = IP_ADD_SOURCE_MEMBERSHIP;
 340         opt.gsr4.imr_multiaddr = grp->sin_addr;
 341         opt.gsr4.imr_sourceaddr = src->sin_addr;
 342         opt.gsr4.imr_interface = id;
 343         optlen = sizeof (opt.gsr4);
 344 # else
 345         errno = ENOSYS;
 346         goto error;
 347 # endif
 348     }
 349     else
 350     {
 351         cmd = IP_ADD_MEMBERSHIP;
 352         opt.gr4.imr_multiaddr = grp->sin_addr;
 353         opt.gr4.imr_interface = id;
 354         optlen = sizeof (opt.gr4);
 355     }
 356
 357     msg_Dbg (obj, "IP_ADD_%sMEMBERSHIP multicast request",
 358              (src != NULL) ? "SOURCE_" : "");
 359
 360     if (setsockopt (fd, SOL_IP, cmd, &opt, optlen) == 0)
 361         return 0;
 362
 363 error:
 364 #endif
 365
 366     msg_Err (obj, "cannot join IPv4 multicast group (%m)");
 367     return -1;
 368 }
 369
 370
 371 static int
 372 net_IPv6Join (vlc_object_t *obj, int fd, const struct sockaddr_in6 *src)
 373 {
 374 #ifdef IPV6_JOIN_GROUP
 375     struct ipv6_mreq gr6;
 376     memset (&gr6, 0, sizeof (gr6));
 377     gr6.ipv6mr_interface = src->sin6_scope_id;
 378     memcpy (&gr6.ipv6mr_multiaddr, &src->sin6_addr, 16);
 379
 380     msg_Dbg (obj, "IPV6_JOIN_GROUP multicast request");
 381
 382     if (!setsockopt (fd, SOL_IPV6, IPV6_JOIN_GROUP, &gr6, sizeof (gr6)))
 383         return 0;
 384 #else
 385     errno = ENOSYS;
 386 #endif
 387
 388     msg_Err (obj, "cannot join IPv6 any-source multicast group (%m)");
 389     return -1;
 390 }
 391
 392
 393 #if defined (WIN32) && !defined (MCAST_JOIN_SOURCE_GROUP)
 394 /*
 395  * I hate manual definitions: Error-prone. Portability hell.
 396  * Developers shall use UP-TO-DATE compilers. Full point.
 397  * If you remove the warning, you remove the whole ifndef.
 398  */
 399 #  warning Your C headers are out-of-date. Please update.
 400
 401 #  define MCAST_JOIN_GROUP 41
 402 struct group_req
 403 {
 404     ULONG gr_interface;
 405     struct sockaddr_storage gr_group;
 406 };
 407
 408 #  define MCAST_JOIN_SOURCE_GROUP 45 /* from <ws2ipdef.h> */
 409 struct group_source_req
 410 {
 411     uint32_t gsr_interface;
 412     struct sockaddr_storage gsr_group;
 413     struct sockaddr_storage gsr_source;
 414 };
 415 #endif
 416
 417 /**
 418  * IP-agnostic multicast join,
 419  * with fallback to old APIs, and fallback from SSM to ASM.
 420  */
 421 static int
 422 net_SourceSubscribe (vlc_object_t *obj, int fd,
 423                      const struct sockaddr *src, socklen_t srclen,
 424                      const struct sockaddr *grp, socklen_t grplen)
 425 {
 426     int level, iid = 0;
 427
 428     char *iface = var_CreateGetNonEmptyString (obj, "miface");
 429     if (iface != NULL)
 430     {
 431         iid = if_nametoindex (iface);
 432         if (iid == 0)
 433         {
 434             msg_Err (obj, "invalid multicast interface: %s", iface);
 435             free (iface);
 436             return -1;
 437         }
 438         free (iface);
 439     }
 440
 441     switch (grp->sa_family)
 442     {
 443 #ifdef AF_INET6
 444         case AF_INET6:
 445             level = SOL_IPV6;
 446             if (((const struct sockaddr_in6 *)grp)->sin6_scope_id)
 447                 iid = ((const struct sockaddr_in6 *)grp)->sin6_scope_id;
 448             break;
 449 #endif
 450
 451         case AF_INET:
 452             level = SOL_IP;
 453             break;
 454
 455         default:
 456             errno = EAFNOSUPPORT;
 457             return -1;
 458     }
 459
 460     if (src != NULL)
 461         switch (src->sa_family)
 462         {
 463 #ifdef AF_INET6
 464             case AF_INET6:
 465                 if (memcmp (&((const struct sockaddr_in6 *)src)->sin6_addr,
 466                             &in6addr_any, sizeof (in6addr_any)) == 0)
 467                     src = NULL;
 468             break;
 469 #endif
 470
 471             case AF_INET:
 472                 if (((const struct sockaddr_in *)src)->sin_addr.s_addr
 473                      == INADDR_ANY)
 474                     src = NULL;
 475                 break;
 476         }
 477
 478
 479     /* Agnostic ASM/SSM multicast join */
 480 #ifdef MCAST_JOIN_SOURCE_GROUP
 481     union
 482     {
 483         struct group_req gr;
 484         struct group_source_req gsr;
 485     } opt;
 486     socklen_t optlen;
 487
 488     memset (&opt, 0, sizeof (opt));
 489
 490     if (src != NULL)
 491     {
 492         if ((grplen > sizeof (opt.gsr.gsr_group))
 493          || (srclen > sizeof (opt.gsr.gsr_source)))
 494             return -1;
 495
 496         opt.gsr.gsr_interface = iid;
 497         memcpy (&opt.gsr.gsr_source, src, srclen);
 498         memcpy (&opt.gsr.gsr_group,  grp, grplen);
 499         optlen = sizeof (opt.gsr);
 500     }
 501     else
 502     {
 503         if (grplen > sizeof (opt.gr.gr_group))
 504             return -1;
 505
 506         opt.gr.gr_interface = iid;
 507         memcpy (&opt.gr.gr_group, grp, grplen);
 508         optlen = sizeof (opt.gr);
 509     }
 510
 511     msg_Dbg (obj, "Multicast %sgroup join request", src ? "source " : "");
 512
 513     if (setsockopt (fd, level,
 514                     src ? MCAST_JOIN_SOURCE_GROUP : MCAST_JOIN_GROUP,
 515                     (void *)&opt, optlen) == 0)
 516         return 0;
 517 #endif
 518
 519     /* Fallback to IPv-specific APIs */
 520     if ((src != NULL) && (src->sa_family != grp->sa_family))
 521         return -1;
 522
 523     switch (grp->sa_family)
 524     {
 525         case AF_INET:
 526             if ((grplen < sizeof (struct sockaddr_in))
 527              || ((src != NULL) && (srclen < sizeof (struct sockaddr_in))))
 528                 return -1;
 529
 530             if (net_IPv4Join (obj, fd, (const struct sockaddr_in *)src,
 531                               (const struct sockaddr_in *)grp) == 0)
 532                 return 0;
 533             break;
 534
 535 #ifdef AF_INET6
 536         case AF_INET6:
 537             if ((grplen < sizeof (struct sockaddr_in6))
 538              || ((src != NULL) && (srclen < sizeof (struct sockaddr_in6))))
 539                 return -1;
 540
 541             /* IPv6-specific SSM API does not exist. So if we're here
 542              * it means IPv6 SSM is not supported on this OS and we
 543              * directly fallback to ASM */
 544
 545             if (net_IPv6Join (obj, fd, (const struct sockaddr_in6 *)grp) == 0)
 546                 return 0;
 547             break;
 548 #endif
 549     }
 550
 551     msg_Err (obj, "Multicast group join error (%m)");
 552
 553     if (src != NULL)
 554     {
 555         msg_Warn (obj, "Trying ASM instead of SSM...");
 556         return net_Subscribe (obj, fd, grp, grplen);
 557     }
 558
 559     msg_Err (obj, "Multicast not supported");
 560     return -1;
 561 }
 562
 563
 564 int net_Subscribe (vlc_object_t *obj, int fd,
 565                    const struct sockaddr *addr, socklen_t addrlen)
 566 {
 567     return net_SourceSubscribe (obj, fd, NULL, 0, addr, addrlen);
 568 }
 569
 570
 571 static int net_SetDSCP( int fd, uint8_t dscp )
 572 {
 573     struct sockaddr_storage addr;
 574     if( getsockname( fd, (struct sockaddr *)&addr, &(socklen_t){ sizeof (addr) }) )
 575         return -1;
 576
 577     int level, cmd;
 578
 579     switch( addr.ss_family )
 580     {
 581 #ifdef IPV6_TCLASS
 582         case AF_INET6:
 583             level = SOL_IPV6;
 584             cmd = IPV6_TCLASS;
 585             break;
 586 #endif
 587
 588         case AF_INET:
 589             level = SOL_IP;
 590             cmd = IP_TOS;
 591             break;
 592
 593         default:
 594 #ifdef ENOPROTOOPT
 595             errno = ENOPROTOOPT;
 596 #endif
 597             return -1;
 598     }
 599
 600     return setsockopt( fd, level, cmd, &(int){ dscp }, sizeof (int));
 601 }
 602
 603
 604 /*****************************************************************************
 605  * __net_ConnectDgram:
 606  *****************************************************************************
 607  * Open a datagram socket to send data to a defined destination, with an
 608  * optional hop limit.
 609  *****************************************************************************/
 610 int __net_ConnectDgram( vlc_object_t *p_this, const char *psz_host, int i_port,
 611                         int i_hlim, int proto )
 612 {
 613     struct addrinfo hints, *res, *ptr;
 614     int             i_val, i_handle = -1;
 615     vlc_bool_t      b_unreach = VLC_FALSE;
 616
 617     if( i_port == 0 )
 618         i_port = 1234; /* historical VLC thing */
 619
 620     if( i_hlim < 1 )
 621         i_hlim = var_CreateGetInteger( p_this, "ttl" );
 622
 623     memset( &hints, 0, sizeof( hints ) );
 624     hints.ai_socktype = SOCK_DGRAM;
 625
 626     msg_Dbg( p_this, "net: connecting to %s port %d", psz_host, i_port );
 627
 628     i_val = vlc_getaddrinfo( p_this, psz_host, i_port, &hints, &res );
 629     if( i_val )
 630     {
 631         msg_Err( p_this, "cannot resolve %s port %d : %s", psz_host, i_port,
 632                  vlc_gai_strerror( i_val ) );
 633         return -1;
 634     }
 635
 636     for( ptr = res; ptr != NULL; ptr = ptr->ai_next )
 637     {
 638         char *str;
 639         int fd = net_Socket (p_this, ptr->ai_family, ptr->ai_socktype,
 640                              proto ?: ptr->ai_protocol);
 641         if (fd == -1)
 642             continue;
 643
 644 #if !defined( SYS_BEOS )
 645         /* Increase the receive buffer size to 1/2MB (8Mb/s during 1/2s)
 646         * to avoid packet loss caused by scheduling problems */
 647         setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &(int){ 0x80000 }, sizeof (int));
 648         setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &(int){ 0x80000 }, sizeof (int));
 649
 650         /* Allow broadcast sending */
 651         setsockopt (fd, SOL_SOCKET, SO_BROADCAST, &(int){ 1 }, sizeof (int));
 652 #endif
 653
 654         if( i_hlim > 0 )
 655             net_SetMcastHopLimit( p_this, fd, ptr->ai_family, i_hlim );
 656
 657         str = var_CreateGetNonEmptyString (p_this, "miface");
 658         if (str != NULL)
 659         {
 660             net_SetMcastOut (p_this, fd, ptr->ai_family, str, NULL);
 661             free (str);
 662         }
 663
 664         str = var_CreateGetNonEmptyString (p_this, "miface-addr");
 665         if (str != NULL)
 666         {
 667             net_SetMcastOut (p_this, fd, ptr->ai_family, NULL, str);
 668             free (str);
 669         }
 670
 671         net_SetDSCP (fd, var_CreateGetInteger (p_this, "dscp"));
 672
 673         if( connect( fd, ptr->ai_addr, ptr->ai_addrlen ) == 0 )
 674         {
 675             /* success */
 676             i_handle = fd;
 677             break;
 678         }
 679
 680 #if defined( WIN32 ) || defined( UNDER_CE )
 681         if( WSAGetLastError () == WSAENETUNREACH )
 682 #else
 683         if( errno == ENETUNREACH )
 684 #endif
 685             b_unreach = VLC_TRUE;
 686         else
 687         {
 688             msg_Warn( p_this, "%s port %d : %m", psz_host, i_port);
 689             net_Close( fd );
 690             continue;
 691         }
 692     }
 693
 694     vlc_freeaddrinfo( res );
 695
 696     if( i_handle == -1 )
 697     {
 698         if( b_unreach )
 699             msg_Err( p_this, "Host %s port %d is unreachable", psz_host,
 700                      i_port );
 701         return -1;
 702     }
 703
 704     return i_handle;
 705 }
 706
 707
 708 /*****************************************************************************
 709  * __net_OpenDgram:
 710  *****************************************************************************
 711  * OpenDgram a datagram socket and return a handle
 712  *****************************************************************************/
 713 int __net_OpenDgram( vlc_object_t *obj, const char *psz_bind, int i_bind,
 714                      const char *psz_server, int i_server,
 715                      int family, int protocol )
 716 {
 717     if ((psz_server == NULL) || (psz_server[0] == '\0'))
 718         return net_ListenSingle (obj, psz_bind, i_bind, family, protocol);
 719
 720     msg_Dbg (obj, "net: connecting to [%s]:%d from [%s]:%d",
 721              psz_server, i_server, psz_bind, i_bind);
 722
 723     struct addrinfo hints, *loc, *rem;
 724     int val;
 725
 726     memset (&hints, 0, sizeof (hints));
 727     hints.ai_family = family;
 728     hints.ai_socktype = SOCK_DGRAM;
 729
 730     val = vlc_getaddrinfo (obj, psz_server, i_server, &hints, &rem);
 731     if (val)
 732     {
 733         msg_Err (obj, "cannot resolve %s port %d : %s", psz_bind, i_bind,
 734                  vlc_gai_strerror (val));
 735         return -1;
 736     }
 737
 738     hints.ai_flags = AI_PASSIVE;
 739     val = vlc_getaddrinfo (obj, psz_bind, i_bind, &hints, &loc);
 740     if (val)
 741     {
 742         msg_Err (obj, "cannot resolve %s port %d : %s", psz_bind, i_bind,
 743                  vlc_gai_strerror (val));
 744         vlc_freeaddrinfo (rem);
 745         return -1;
 746     }
 747
 748     for (struct addrinfo *ptr = loc; ptr != NULL; ptr = ptr->ai_next)
 749     {
 750         int fd = net_Socket (obj, ptr->ai_family, ptr->ai_socktype,
 751                              protocol ?: ptr->ai_protocol);
 752         if (fd == -1)
 753             continue; // usually, address family not supported
 754
 755 #ifdef SO_REUSEPORT
 756         setsockopt (fd, SOL_SOCKET, SO_REUSEPORT, &(int){ 1 }, sizeof (int));
 757 #endif
 758
 759 #ifdef SO_RCVBUF
 760         /* Increase the receive buffer size to 1/2MB (8Mb/s during 1/2s)
 761          * to avoid packet loss caused in case of scheduling hiccups */
 762         setsockopt (fd, SOL_SOCKET, SO_RCVBUF,
 763                     (void *)&(int){ 0x80000 }, sizeof (int));
 764         setsockopt (fd, SOL_SOCKET, SO_SNDBUF,
 765                     (void *)&(int){ 0x80000 }, sizeof (int));
 766 #endif
 767
 768 #if defined (WIN32) || defined (UNDER_CE)
 769         if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 770          && (sizeof (struct sockaddr_storage) >= ptr->ai_addrlen))
 771         {
 772             // This works for IPv4 too - don't worry!
 773             struct sockaddr_in6 dumb =
 774             {
 775                 .sin6_family = ptr->ai_addr->sa_family,
 776                 .sin6_port =  ((struct sockaddr_in *)(ptr->ai_addr))->sin_port
 777             };
 778
 779             bind (fd, (struct sockaddr *)&dumb, ptr->ai_addrlen);
 780         }
 781         else
 782 #endif
 783         if (bind (fd, ptr->ai_addr, ptr->ai_addrlen))
 784         {
 785             net_Close (fd);
 786             continue;
 787         }
 788
 789         val = -1;
 790         for (struct addrinfo *ptr2 = rem; ptr2 != NULL; ptr2 = ptr2->ai_next)
 791         {
 792             if ((ptr2->ai_family != ptr->ai_family)
 793              || (ptr2->ai_socktype != ptr->ai_socktype)
 794              || (ptr2->ai_protocol != ptr->ai_protocol))
 795                 continue;
 796
 797             if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 798               ? net_SourceSubscribe (obj, fd,
 799                                      ptr2->ai_addr, ptr2->ai_addrlen,
 800                                      ptr->ai_addr, ptr->ai_addrlen)
 801               : connect (fd, ptr2->ai_addr, ptr2->ai_addrlen))
 802             {
 803                 msg_Err (obj, "cannot connect to %s port %d: %m",
 804                          psz_server, i_server);
 805                 continue;
 806             }
 807             val = fd;
 808             break;
 809         }
 810
 811         if (val != -1)
 812             break;
 813
 814         close (fd);
 815     }
 816
 817     vlc_freeaddrinfo (rem);
 818     vlc_freeaddrinfo (loc);
 819     return val;
 820 }
 821
 822
 823 /**
 824  * net_SetCSCov:
 825  * Sets the send and receive checksum coverage of a socket:
 826  * @param fd socket
 827  * @param sendcov payload coverage of sent packets (bytes), -1 for full
 828  * @param recvcov minimum payload coverage of received packets, -1 for full
 829  */
 830 int net_SetCSCov (int fd, int sendcov, int recvcov)
 831 {
 832     int type;
 833
 834     if (getsockopt (fd, SOL_SOCKET, SO_TYPE,
 835                     &type, &(socklen_t){ sizeof (type) }))
 836         return VLC_EGENERIC;
 837
 838     switch (type)
 839     {
 840 #ifdef UDPLITE_RECV_CSCOV
 841         case SOCK_DGRAM: /* UDP-Lite */
 842             if (sendcov == -1)
 843                 sendcov = 0;
 844             else
 845                 sendcov += 8; /* partial */
 846             if (setsockopt (fd, SOL_UDPLITE, UDPLITE_SEND_CSCOV, &sendcov,
 847                             sizeof (sendcov)))
 848                 return VLC_EGENERIC;
 849
 850             if (recvcov == -1)
 851                 recvcov = 0;
 852             else
 853                 recvcov += 8;
 854             if (setsockopt (fd, SOL_UDPLITE, UDPLITE_RECV_CSCOV,
 855                             &recvcov, sizeof (recvcov)))
 856                 return VLC_EGENERIC;
 857
 858             return VLC_SUCCESS;
 859 #endif
 860 #ifdef DCCP_SOCKOPT_SEND_CSCOV
 861         case SOCK_DCCP: /* DCCP and its ill-named socket type */
 862             if ((sendcov == -1) || (sendcov > 56))
 863                 sendcov = 0;
 864             else
 865                 sendcov = (sendcov + 3) / 4;
 866             if (setsockopt (fd, SOL_DCCP, DCCP_SOCKOPT_SEND_CSCOV,
 867                             &sendcov, sizeof (sendcov)))
 868                 return VLC_EGENERIC;
 869
 870             if ((recvcov == -1) || (recvcov > 56))
 871                 recvcov = 0;
 872             else
 873                 recvcov = (recvcov + 3) / 4;
 874             if (setsockopt (fd, SOL_DCCP, DCCP_SOCKOPT_RECV_CSCOV,
 875                             &recvcov, sizeof (recvcov)))
 876                 return VLC_EGENERIC;
 877
 878             return VLC_SUCCESS;
 879 #endif
 880     }
 881
 882     return VLC_EGENERIC;
 883 }