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 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc_common.h>
  35
  36 #include <errno.h>
  37
  38 #ifdef HAVE_SYS_TIME_H
  39 #    include <sys/time.h>
  40 #endif
  41
  42 #include <vlc_network.h>
  43
  44 #ifdef WIN32
  45 #   if defined(UNDER_CE)
  46 #       undef IP_MULTICAST_TTL
  47 #       define IP_MULTICAST_TTL 3
  48 #       undef IP_ADD_MEMBERSHIP
  49 #       define IP_ADD_MEMBERSHIP 5
  50 #   endif
  51 #   define EAFNOSUPPORT WSAEAFNOSUPPORT
  52 #   define if_nametoindex( str ) atoi( str )
  53 #else
  54 #   include <unistd.h>
  55 #   ifdef HAVE_NET_IF_H
  56 #       include <net/if.h>
  57 #   endif
  58 #endif
  59
  60 #ifdef HAVE_LINUX_DCCP_H
  61 # include <linux/dccp.h>
  62 # ifndef SOCK_DCCP /* provisional API */
  63 #  define SOCK_DCCP 6
  64 # endif
  65 #endif
  66
  67 #ifndef SOL_IP
  68 # define SOL_IP IPPROTO_IP
  69 #endif
  70 #ifndef SOL_IPV6
  71 # define SOL_IPV6 IPPROTO_IPV6
  72 #endif
  73 #ifndef IPPROTO_IPV6
  74 # define IPPROTO_IPV6 41 /* IANA */
  75 #endif
  76 #ifndef SOL_DCCP
  77 # define SOL_DCCP IPPROTO_DCCP
  78 #endif
  79 #ifndef IPPROTO_DCCP
  80 # define IPPROTO_DCCP 33 /* IANA */
  81 #endif
  82 #ifndef SOL_UDPLITE
  83 # define SOL_UDPLITE IPPROTO_UDPLITE
  84 #endif
  85 #ifndef IPPROTO_UDPLITE
  86 # define IPPROTO_UDPLITE 136 /* IANA */
  87 #endif
  88
  89 #if defined (HAVE_NETINET_UDPLITE_H)
  90 # include <netinet/udplite.h>
  91 #elif defined (__linux__)
  92 /* still missing from glibc 2.6 */
  93 # define UDPLITE_SEND_CSCOV     10
  94 # define UDPLITE_RECV_CSCOV     11
  95 #endif
  96
  97 extern int net_Socket( vlc_object_t *p_this, int i_family, int i_socktype,
  98                        int i_protocol );
  99
 100 static int net_ListenSingle (vlc_object_t *obj, const char *host, int port,
 101                              int family, int protocol)
 102 {
 103     struct addrinfo hints, *res;
 104
 105     memset (&hints, 0, sizeof( hints ));
 106     hints.ai_family = family;
 107     hints.ai_socktype = SOCK_DGRAM;
 108     hints.ai_flags = AI_PASSIVE;
 109
 110     if (host && !*host)
 111         host = NULL;
 112
 113     msg_Dbg (obj, "net: opening %s datagram port %d", host ?: "any", port);
 114
 115     int val = vlc_getaddrinfo (obj, host, port, &hints, &res);
 116     if (val)
 117     {
 118         msg_Err (obj, "Cannot resolve %s port %d : %s", host, port,
 119                  vlc_gai_strerror (val));
 120         return -1;
 121     }
 122
 123     val = -1;
 124
 125     for (const struct addrinfo *ptr = res; ptr != NULL; ptr = ptr->ai_next)
 126     {
 127         int fd = net_Socket (obj, ptr->ai_family, ptr->ai_socktype,
 128                              protocol ?: ptr->ai_protocol);
 129         if (fd == -1)
 130         {
 131             msg_Dbg (obj, "socket error: %m");
 132             continue;
 133         }
 134
 135         if (ptr->ai_next != NULL)
 136         {
 137 #ifdef IPV6_V6ONLY
 138             if ((ptr->ai_family != AF_INET6)
 139              || setsockopt (fd, SOL_IPV6, IPV6_V6ONLY, &(int){ 0 },
 140                             sizeof (int)))
 141 #endif
 142             {
 143                 msg_Err (obj, "Multiple network protocols present");
 144                 msg_Err (obj, "Please select network protocol manually");
 145             }
 146         }
 147
 148         /* Bind the socket */
 149 #if defined (WIN32) || defined (UNDER_CE)
 150         if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 151          && (sizeof (struct sockaddr_storage) >= ptr->ai_addrlen))
 152         {
 153             struct sockaddr_in6 dumb =
 154             {
 155                 .sin6_family = ptr->ai_addr->sa_family,
 156                 .sin6_port =  ((struct sockaddr_in *)(ptr->ai_addr))->sin_port
 157             };
 158             bind (fd, (struct sockaddr *)&dumb, ptr->ai_addrlen);
 159         }
 160         else
 161 #endif
 162         if (bind (fd, ptr->ai_addr, ptr->ai_addrlen))
 163         {
 164             msg_Err (obj, "socket bind error (%m)");
 165             net_Close (fd);
 166             continue;
 167         }
 168
 169         if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 170          && net_Subscribe (obj, fd, ptr->ai_addr, ptr->ai_addrlen))
 171         {
 172             net_Close (fd);
 173             continue;
 174         }
 175
 176         val = fd;
 177         break;
 178     }
 179
 180     vlc_freeaddrinfo (res);
 181     return val;
 182 }
 183
 184
 185 static int net_SetMcastHopLimit( vlc_object_t *p_this,
 186                                  int fd, int family, int hlim )
 187 {
 188     int proto, cmd;
 189
 190     /* There is some confusion in the world whether IP_MULTICAST_TTL
 191      * takes a byte or an int as an argument.
 192      * BSD seems to indicate byte so we are going with that and use
 193      * int as a fallback to be safe */
 194     switch( family )
 195     {
 196 #ifdef IP_MULTICAST_TTL
 197         case AF_INET:
 198             proto = SOL_IP;
 199             cmd = IP_MULTICAST_TTL;
 200             break;
 201 #endif
 202
 203 #ifdef IPV6_MULTICAST_HOPS
 204         case AF_INET6:
 205             proto = SOL_IPV6;
 206             cmd = IPV6_MULTICAST_HOPS;
 207             break;
 208 #endif
 209
 210         default:
 211             errno = EAFNOSUPPORT;
 212             msg_Warn( p_this, "%m" );
 213             return VLC_EGENERIC;
 214     }
 215
 216     if( setsockopt( fd, proto, cmd, &hlim, sizeof( hlim ) ) < 0 )
 217     {
 218         /* BSD compatibility */
 219         unsigned char buf;
 220
 221         buf = (unsigned char)(( hlim > 255 ) ? 255 : hlim);
 222         if( setsockopt( fd, proto, cmd, &buf, sizeof( buf ) ) )
 223             return VLC_EGENERIC;
 224     }
 225
 226     return VLC_SUCCESS;
 227 }
 228
 229
 230 static int net_SetMcastOutIface (int fd, int family, int scope)
 231 {
 232     switch (family)
 233     {
 234 #ifdef IPV6_MULTICAST_IF
 235         case AF_INET6:
 236             return setsockopt (fd, SOL_IPV6, IPV6_MULTICAST_IF,
 237                                &scope, sizeof (scope));
 238 #endif
 239
 240 #ifdef __linux__
 241         case AF_INET:
 242         {
 243             struct ip_mreqn req = { .imr_ifindex = scope };
 244
 245             return setsockopt (fd, SOL_IP, IP_MULTICAST_IF, &req,
 246                                sizeof (req));
 247         }
 248 #endif
 249     }
 250
 251     errno = EAFNOSUPPORT;
 252     return -1;
 253 }
 254
 255
 256 static inline int net_SetMcastOutIPv4 (int fd, struct in_addr ipv4)
 257 {
 258 #ifdef IP_MULTICAST_IF
 259     return setsockopt( fd, SOL_IP, IP_MULTICAST_IF, &ipv4, sizeof (ipv4));
 260 #else
 261     errno = EAFNOSUPPORT;
 262     return -1;
 263 #endif
 264 }
 265
 266
 267 static int net_SetMcastOut (vlc_object_t *p_this, int fd, int family,
 268                             const char *iface, const char *addr)
 269 {
 270     if (iface != NULL)
 271     {
 272         int scope = if_nametoindex (iface);
 273         if (scope == 0)
 274         {
 275             msg_Err (p_this, "invalid multicast interface: %s", iface);
 276             return -1;
 277         }
 278
 279         if (net_SetMcastOutIface (fd, family, scope) == 0)
 280             return 0;
 281
 282         msg_Err (p_this, "%s: %m", iface);
 283     }
 284
 285     if (addr != NULL)
 286     {
 287         if (family == AF_INET)
 288         {
 289             struct in_addr ipv4;
 290             if (inet_pton (AF_INET, addr, &ipv4) <= 0)
 291             {
 292                 msg_Err (p_this, "invalid IPv4 address for multicast: %s",
 293                          addr);
 294                 return -1;
 295             }
 296
 297             if (net_SetMcastOutIPv4 (fd, ipv4) == 0)
 298                 return 0;
 299
 300             msg_Err (p_this, "%s: %m", addr);
 301         }
 302     }
 303
 304     return -1;
 305 }
 306
 307
 308 /**
 309  * Old-style any-source multicast join.
 310  * In use on Windows XP/2003 and older.
 311  */
 312 static int
 313 net_IPv4Join (vlc_object_t *obj, int fd,
 314               const struct sockaddr_in *src, const struct sockaddr_in *grp)
 315 {
 316 #ifdef IP_ADD_MEMBERSHIP
 317     union
 318     {
 319         struct ip_mreq gr4;
 320 # ifdef IP_ADD_SOURCE_MEMBERSHIP
 321         struct ip_mreq_source gsr4;
 322 # endif
 323     } opt;
 324     int cmd;
 325     struct in_addr id = { .s_addr = INADDR_ANY };
 326     socklen_t optlen;
 327
 328     /* Multicast interface IPv4 address */
 329     char *iface = var_CreateGetNonEmptyString (obj, "miface-addr");
 330     if ((iface != NULL)
 331      && (inet_pton (AF_INET, iface, &id) <= 0))
 332     {
 333         msg_Err (obj, "invalid multicast interface address %s", iface);
 334         free (iface);
 335         goto error;
 336     }
 337     free (iface);
 338
 339     memset (&opt, 0, sizeof (opt));
 340     if (src != NULL)
 341     {
 342 # ifdef IP_ADD_SOURCE_MEMBERSHIP
 343         cmd = IP_ADD_SOURCE_MEMBERSHIP;
 344         opt.gsr4.imr_multiaddr = grp->sin_addr;
 345         opt.gsr4.imr_sourceaddr = src->sin_addr;
 346         opt.gsr4.imr_interface = id;
 347         optlen = sizeof (opt.gsr4);
 348 # else
 349         errno = ENOSYS;
 350         goto error;
 351 # endif
 352     }
 353     else
 354     {
 355         cmd = IP_ADD_MEMBERSHIP;
 356         opt.gr4.imr_multiaddr = grp->sin_addr;
 357         opt.gr4.imr_interface = id;
 358         optlen = sizeof (opt.gr4);
 359     }
 360
 361     msg_Dbg (obj, "IP_ADD_%sMEMBERSHIP multicast request",
 362              (src != NULL) ? "SOURCE_" : "");
 363
 364     if (setsockopt (fd, SOL_IP, cmd, &opt, optlen) == 0)
 365         return 0;
 366
 367 error:
 368 #endif
 369
 370     msg_Err (obj, "cannot join IPv4 multicast group (%m)");
 371     return -1;
 372 }
 373
 374
 375 static int
 376 net_IPv6Join (vlc_object_t *obj, int fd, const struct sockaddr_in6 *src)
 377 {
 378 #ifdef IPV6_JOIN_GROUP
 379     struct ipv6_mreq gr6;
 380     memset (&gr6, 0, sizeof (gr6));
 381     gr6.ipv6mr_interface = src->sin6_scope_id;
 382     memcpy (&gr6.ipv6mr_multiaddr, &src->sin6_addr, 16);
 383
 384     msg_Dbg (obj, "IPV6_JOIN_GROUP multicast request");
 385
 386     if (!setsockopt (fd, SOL_IPV6, IPV6_JOIN_GROUP, &gr6, sizeof (gr6)))
 387         return 0;
 388 #else
 389     errno = ENOSYS;
 390 #endif
 391
 392     msg_Err (obj, "cannot join IPv6 any-source multicast group (%m)");
 393     return -1;
 394 }
 395
 396
 397 #if defined (WIN32) && !defined (MCAST_JOIN_SOURCE_GROUP)
 398 /*
 399  * I hate manual definitions: Error-prone. Portability hell.
 400  * Developers shall use UP-TO-DATE compilers. Full point.
 401  * If you remove the warning, you remove the whole ifndef.
 402  */
 403 #  warning Your C headers are out-of-date. Please update.
 404
 405 #  define MCAST_JOIN_GROUP 41
 406 struct group_req
 407 {
 408     ULONG gr_interface;
 409     struct sockaddr_storage gr_group;
 410 };
 411
 412 #  define MCAST_JOIN_SOURCE_GROUP 45 /* from <ws2ipdef.h> */
 413 struct group_source_req
 414 {
 415     uint32_t gsr_interface;
 416     struct sockaddr_storage gsr_group;
 417     struct sockaddr_storage gsr_source;
 418 };
 419 #endif
 420
 421 /**
 422  * IP-agnostic multicast join,
 423  * with fallback to old APIs, and fallback from SSM to ASM.
 424  */
 425 static int
 426 net_SourceSubscribe (vlc_object_t *obj, int fd,
 427                      const struct sockaddr *src, socklen_t srclen,
 428                      const struct sockaddr *grp, socklen_t grplen)
 429 {
 430     int level, iid = 0;
 431
 432     char *iface = var_CreateGetNonEmptyString (obj, "miface");
 433     if (iface != NULL)
 434     {
 435         iid = if_nametoindex (iface);
 436         if (iid == 0)
 437         {
 438             msg_Err (obj, "invalid multicast interface: %s", iface);
 439             free (iface);
 440             return -1;
 441         }
 442         free (iface);
 443     }
 444
 445     switch (grp->sa_family)
 446     {
 447 #ifdef AF_INET6
 448         case AF_INET6:
 449             level = SOL_IPV6;
 450             if (((const struct sockaddr_in6 *)grp)->sin6_scope_id)
 451                 iid = ((const struct sockaddr_in6 *)grp)->sin6_scope_id;
 452             break;
 453 #endif
 454
 455         case AF_INET:
 456             level = SOL_IP;
 457             break;
 458
 459         default:
 460             errno = EAFNOSUPPORT;
 461             return -1;
 462     }
 463
 464     if (src != NULL)
 465         switch (src->sa_family)
 466         {
 467 #ifdef AF_INET6
 468             case AF_INET6:
 469                 if (memcmp (&((const struct sockaddr_in6 *)src)->sin6_addr,
 470                             &in6addr_any, sizeof (in6addr_any)) == 0)
 471                     src = NULL;
 472             break;
 473 #endif
 474
 475             case AF_INET:
 476                 if (((const struct sockaddr_in *)src)->sin_addr.s_addr
 477                      == INADDR_ANY)
 478                     src = NULL;
 479                 break;
 480         }
 481
 482
 483     /* Agnostic ASM/SSM multicast join */
 484 #ifdef MCAST_JOIN_SOURCE_GROUP
 485     union
 486     {
 487         struct group_req gr;
 488         struct group_source_req gsr;
 489     } opt;
 490     socklen_t optlen;
 491
 492     memset (&opt, 0, sizeof (opt));
 493
 494     if (src != NULL)
 495     {
 496         if ((grplen > sizeof (opt.gsr.gsr_group))
 497          || (srclen > sizeof (opt.gsr.gsr_source)))
 498             return -1;
 499
 500         opt.gsr.gsr_interface = iid;
 501         memcpy (&opt.gsr.gsr_source, src, srclen);
 502         memcpy (&opt.gsr.gsr_group,  grp, grplen);
 503         optlen = sizeof (opt.gsr);
 504     }
 505     else
 506     {
 507         if (grplen > sizeof (opt.gr.gr_group))
 508             return -1;
 509
 510         opt.gr.gr_interface = iid;
 511         memcpy (&opt.gr.gr_group, grp, grplen);
 512         optlen = sizeof (opt.gr);
 513     }
 514
 515     msg_Dbg (obj, "Multicast %sgroup join request", src ? "source " : "");
 516
 517     if (setsockopt (fd, level,
 518                     src ? MCAST_JOIN_SOURCE_GROUP : MCAST_JOIN_GROUP,
 519                     (void *)&opt, optlen) == 0)
 520         return 0;
 521 #endif
 522
 523     /* Fallback to IPv-specific APIs */
 524     if ((src != NULL) && (src->sa_family != grp->sa_family))
 525         return -1;
 526
 527     switch (grp->sa_family)
 528     {
 529         case AF_INET:
 530             if ((grplen < sizeof (struct sockaddr_in))
 531              || ((src != NULL) && (srclen < sizeof (struct sockaddr_in))))
 532                 return -1;
 533
 534             if (net_IPv4Join (obj, fd, (const struct sockaddr_in *)src,
 535                               (const struct sockaddr_in *)grp) == 0)
 536                 return 0;
 537             break;
 538
 539 #ifdef AF_INET6
 540         case AF_INET6:
 541             if ((grplen < sizeof (struct sockaddr_in6))
 542              || ((src != NULL) && (srclen < sizeof (struct sockaddr_in6))))
 543                 return -1;
 544
 545             /* IPv6-specific SSM API does not exist. So if we're here
 546              * it means IPv6 SSM is not supported on this OS and we
 547              * directly fallback to ASM */
 548
 549             if (net_IPv6Join (obj, fd, (const struct sockaddr_in6 *)grp) == 0)
 550                 return 0;
 551             break;
 552 #endif
 553     }
 554
 555     msg_Err (obj, "Multicast group join error (%m)");
 556
 557     if (src != NULL)
 558     {
 559         msg_Warn (obj, "Trying ASM instead of SSM...");
 560         return net_Subscribe (obj, fd, grp, grplen);
 561     }
 562
 563     msg_Err (obj, "Multicast not supported");
 564     return -1;
 565 }
 566
 567
 568 int net_Subscribe (vlc_object_t *obj, int fd,
 569                    const struct sockaddr *addr, socklen_t addrlen)
 570 {
 571     return net_SourceSubscribe (obj, fd, NULL, 0, addr, addrlen);
 572 }
 573
 574
 575 static int net_SetDSCP( int fd, uint8_t dscp )
 576 {
 577     struct sockaddr_storage addr;
 578     if( getsockname( fd, (struct sockaddr *)&addr, &(socklen_t){ sizeof (addr) }) )
 579         return -1;
 580
 581     int level, cmd;
 582
 583     switch( addr.ss_family )
 584     {
 585 #ifdef IPV6_TCLASS
 586         case AF_INET6:
 587             level = SOL_IPV6;
 588             cmd = IPV6_TCLASS;
 589             break;
 590 #endif
 591
 592         case AF_INET:
 593             level = SOL_IP;
 594             cmd = IP_TOS;
 595             break;
 596
 597         default:
 598 #ifdef ENOPROTOOPT
 599             errno = ENOPROTOOPT;
 600 #endif
 601             return -1;
 602     }
 603
 604     return setsockopt( fd, level, cmd, &(int){ dscp }, sizeof (int));
 605 }
 606
 607
 608 /*****************************************************************************
 609  * __net_ConnectDgram:
 610  *****************************************************************************
 611  * Open a datagram socket to send data to a defined destination, with an
 612  * optional hop limit.
 613  *****************************************************************************/
 614 int __net_ConnectDgram( vlc_object_t *p_this, const char *psz_host, int i_port,
 615                         int i_hlim, int proto )
 616 {
 617     struct addrinfo hints, *res, *ptr;
 618     int             i_val, i_handle = -1;
 619     bool      b_unreach = false;
 620
 621     if( i_hlim < 1 )
 622         i_hlim = var_CreateGetInteger( p_this, "ttl" );
 623
 624     memset( &hints, 0, sizeof( hints ) );
 625     hints.ai_socktype = SOCK_DGRAM;
 626
 627     msg_Dbg( p_this, "net: connecting to [%s]:%d", psz_host, i_port );
 628
 629     i_val = vlc_getaddrinfo( p_this, psz_host, i_port, &hints, &res );
 630     if( i_val )
 631     {
 632         msg_Err( p_this, "cannot resolve [%s]:%d : %s", psz_host, i_port,
 633                  vlc_gai_strerror( i_val ) );
 634         return -1;
 635     }
 636
 637     for( ptr = res; ptr != NULL; ptr = ptr->ai_next )
 638     {
 639         char *str;
 640         int fd = net_Socket (p_this, ptr->ai_family, ptr->ai_socktype,
 641                              proto ?: ptr->ai_protocol);
 642         if (fd == -1)
 643             continue;
 644
 645 #if !defined( SYS_BEOS )
 646         /* Increase the receive buffer size to 1/2MB (8Mb/s during 1/2s)
 647         * to avoid packet loss caused by scheduling problems */
 648         setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &(int){ 0x80000 }, sizeof (int));
 649         setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &(int){ 0x80000 }, sizeof (int));
 650
 651         /* Allow broadcast sending */
 652         setsockopt (fd, SOL_SOCKET, SO_BROADCAST, &(int){ 1 }, sizeof (int));
 653 #endif
 654
 655         if( i_hlim > 0 )
 656             net_SetMcastHopLimit( p_this, fd, ptr->ai_family, i_hlim );
 657
 658         str = var_CreateGetNonEmptyString (p_this, "miface");
 659         if (str != NULL)
 660         {
 661             net_SetMcastOut (p_this, fd, ptr->ai_family, str, NULL);
 662             free (str);
 663         }
 664
 665         str = var_CreateGetNonEmptyString (p_this, "miface-addr");
 666         if (str != NULL)
 667         {
 668             net_SetMcastOut (p_this, fd, ptr->ai_family, NULL, str);
 669             free (str);
 670         }
 671
 672         net_SetDSCP (fd, var_CreateGetInteger (p_this, "dscp"));
 673
 674         if( connect( fd, ptr->ai_addr, ptr->ai_addrlen ) == 0 )
 675         {
 676             /* success */
 677             i_handle = fd;
 678             break;
 679         }
 680
 681 #if defined( WIN32 ) || defined( UNDER_CE )
 682         if( WSAGetLastError () == WSAENETUNREACH )
 683 #else
 684         if( errno == ENETUNREACH )
 685 #endif
 686             b_unreach = true;
 687         else
 688         {
 689             msg_Warn( p_this, "%s port %d : %m", psz_host, i_port);
 690             net_Close( fd );
 691             continue;
 692         }
 693     }
 694
 695     vlc_freeaddrinfo( res );
 696
 697     if( i_handle == -1 )
 698     {
 699         if( b_unreach )
 700             msg_Err( p_this, "Host %s port %d is unreachable", psz_host,
 701                      i_port );
 702         return -1;
 703     }
 704
 705     return i_handle;
 706 }
 707
 708
 709 /*****************************************************************************
 710  * __net_OpenDgram:
 711  *****************************************************************************
 712  * OpenDgram a datagram socket and return a handle
 713  *****************************************************************************/
 714 int __net_OpenDgram( vlc_object_t *obj, const char *psz_bind, int i_bind,
 715                      const char *psz_server, int i_server,
 716                      int family, int protocol )
 717 {
 718     if ((psz_server == NULL) || (psz_server[0] == '\0'))
 719         return net_ListenSingle (obj, psz_bind, i_bind, family, protocol);
 720
 721     msg_Dbg (obj, "net: connecting to [%s]:%d from [%s]:%d",
 722              psz_server, i_server, psz_bind, i_bind);
 723
 724     struct addrinfo hints, *loc, *rem;
 725     int val;
 726
 727     memset (&hints, 0, sizeof (hints));
 728     hints.ai_family = family;
 729     hints.ai_socktype = SOCK_DGRAM;
 730
 731     val = vlc_getaddrinfo (obj, psz_server, i_server, &hints, &rem);
 732     if (val)
 733     {
 734         msg_Err (obj, "cannot resolve %s port %d : %s", psz_bind, i_bind,
 735                  vlc_gai_strerror (val));
 736         return -1;
 737     }
 738
 739     hints.ai_flags = AI_PASSIVE;
 740     val = vlc_getaddrinfo (obj, psz_bind, i_bind, &hints, &loc);
 741     if (val)
 742     {
 743         msg_Err (obj, "cannot resolve %s port %d : %s", psz_bind, i_bind,
 744                  vlc_gai_strerror (val));
 745         vlc_freeaddrinfo (rem);
 746         return -1;
 747     }
 748
 749     for (struct addrinfo *ptr = loc; ptr != NULL; ptr = ptr->ai_next)
 750     {
 751         int fd = net_Socket (obj, ptr->ai_family, ptr->ai_socktype,
 752                              protocol ?: ptr->ai_protocol);
 753         if (fd == -1)
 754             continue; // usually, address family not supported
 755
 756 #ifdef SO_REUSEPORT
 757         setsockopt (fd, SOL_SOCKET, SO_REUSEPORT, &(int){ 1 }, sizeof (int));
 758 #endif
 759
 760 #ifdef SO_RCVBUF
 761         /* Increase the receive buffer size to 1/2MB (8Mb/s during 1/2s)
 762          * to avoid packet loss caused in case of scheduling hiccups */
 763         setsockopt (fd, SOL_SOCKET, SO_RCVBUF,
 764                     (void *)&(int){ 0x80000 }, sizeof (int));
 765         setsockopt (fd, SOL_SOCKET, SO_SNDBUF,
 766                     (void *)&(int){ 0x80000 }, sizeof (int));
 767 #endif
 768
 769 #if defined (WIN32) || defined (UNDER_CE)
 770         if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 771          && (sizeof (struct sockaddr_storage) >= ptr->ai_addrlen))
 772         {
 773             // This works for IPv4 too - don't worry!
 774             struct sockaddr_in6 dumb =
 775             {
 776                 .sin6_family = ptr->ai_addr->sa_family,
 777                 .sin6_port =  ((struct sockaddr_in *)(ptr->ai_addr))->sin_port
 778             };
 779
 780             bind (fd, (struct sockaddr *)&dumb, ptr->ai_addrlen);
 781         }
 782         else
 783 #endif
 784         if (bind (fd, ptr->ai_addr, ptr->ai_addrlen))
 785         {
 786             net_Close (fd);
 787             continue;
 788         }
 789
 790         val = -1;
 791         for (struct addrinfo *ptr2 = rem; ptr2 != NULL; ptr2 = ptr2->ai_next)
 792         {
 793             if ((ptr2->ai_family != ptr->ai_family)
 794              || (ptr2->ai_socktype != ptr->ai_socktype)
 795              || (ptr2->ai_protocol != ptr->ai_protocol))
 796                 continue;
 797
 798             if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
 799               ? net_SourceSubscribe (obj, fd,
 800                                      ptr2->ai_addr, ptr2->ai_addrlen,
 801                                      ptr->ai_addr, ptr->ai_addrlen)
 802               : connect (fd, ptr2->ai_addr, ptr2->ai_addrlen))
 803             {
 804                 msg_Err (obj, "cannot connect to %s port %d: %m",
 805                          psz_server, i_server);
 806                 continue;
 807             }
 808             val = fd;
 809             break;
 810         }
 811
 812         if (val != -1)
 813             break;
 814
 815         close (fd);
 816     }
 817
 818     vlc_freeaddrinfo (rem);
 819     vlc_freeaddrinfo (loc);
 820     return val;
 821 }
 822
 823
 824 /**
 825  * net_SetCSCov:
 826  * Sets the send and receive checksum coverage of a socket:
 827  * @param fd socket
 828  * @param sendcov payload coverage of sent packets (bytes), -1 for full
 829  * @param recvcov minimum payload coverage of received packets, -1 for full
 830  */
 831 int net_SetCSCov (int fd, int sendcov, int recvcov)
 832 {
 833     int type;
 834
 835     if (getsockopt (fd, SOL_SOCKET, SO_TYPE,
 836                     &type, &(socklen_t){ sizeof (type) }))
 837         return VLC_EGENERIC;
 838
 839     switch (type)
 840     {
 841 #ifdef UDPLITE_RECV_CSCOV
 842         case SOCK_DGRAM: /* UDP-Lite */
 843             if (sendcov == -1)
 844                 sendcov = 0;
 845             else
 846                 sendcov += 8; /* partial */
 847             if (setsockopt (fd, SOL_UDPLITE, UDPLITE_SEND_CSCOV, &sendcov,
 848                             sizeof (sendcov)))
 849                 return VLC_EGENERIC;
 850
 851             if (recvcov == -1)
 852                 recvcov = 0;
 853             else
 854                 recvcov += 8;
 855             if (setsockopt (fd, SOL_UDPLITE, UDPLITE_RECV_CSCOV,
 856                             &recvcov, sizeof (recvcov)))
 857                 return VLC_EGENERIC;
 858
 859             return VLC_SUCCESS;
 860 #endif
 861 #ifdef DCCP_SOCKOPT_SEND_CSCOV
 862         case SOCK_DCCP: /* DCCP and its ill-named socket type */
 863             if ((sendcov == -1) || (sendcov > 56))
 864                 sendcov = 0;
 865             else
 866                 sendcov = (sendcov + 3) / 4;
 867             if (setsockopt (fd, SOL_DCCP, DCCP_SOCKOPT_SEND_CSCOV,
 868                             &sendcov, sizeof (sendcov)))
 869                 return VLC_EGENERIC;
 870
 871             if ((recvcov == -1) || (recvcov > 56))
 872                 recvcov = 0;
 873             else
 874                 recvcov = (recvcov + 3) / 4;
 875             if (setsockopt (fd, SOL_DCCP, DCCP_SOCKOPT_RECV_CSCOV,
 876                             &recvcov, sizeof (recvcov)))
 877                 return VLC_EGENERIC;
 878
 879             return VLC_SUCCESS;
 880 #endif
 881     }
 882 #if !defined( UDPLITE_RECV_CSCOV ) && !defined( DCCP_SOCKOPT_SEND_CSCOV )
 883     VLC_UNUSED(sendcov);
 884     VLC_UNUSED(recvcov);
 885 #endif
 886
 887     return VLC_EGENERIC;
 888 }