NAME

       lc_share, lc_unshare - share and unshare files over multicast

LIBRARY

       Librecast library (liblibrecast, -llibrecast)

SYNOPSIS

       #include <librecast/net.h>

       lc_share_t *lc_share(lc_ctx_t *lctx, mdex_t *mdex, unsigned int ifx,
                       lc_stat_t *stats, lc_sync_options_t *opt, int flags);
       void lc_unshare(lc_share_t *share);

       Compile and link with -llibrecast.

DESCRIPTION

       The  lc_share  function  shares the objects indexed in mdex on the interface given by ifx.
       If ifx is zero, the files are shared on all multicast-capable interfaces.

       lc_share starts MLD snooping (see IETF RFC 3810). When a join  on  a  new  IPv6  multicast
       group  is  detected,  this  is  checked against the index provided by mdex.  If a matching
       object is found, this is added to  the  sending  queue,  and  the  data  for  this  object
       continues to be sent until MLD reports that there are no more listeners for this group.

       The data sent is encoded using RaptorQ Forward Error Correction (see IETF RFC 6330), using
       the LCRQ library.

       If stats is not NULL, transfer statistics will be returned in this structure.

       opt is not used, at present, and must be NULL for compatibility with future versions.

       The flags argument is the bitwise OR of zero of more of the following flags:

       LC_SHARE_LOOPBACK
              Set the loopback option IPV6_MULTICAST_LOOP on the sending socket.

RETURN VALUE

       lc_share() returns a pointer to a lc_share_t handle, which should be freed by  passing  to
       lc_unshare()  when  done.   On  error,  NULL is returned, and errno is set to indicate the
       error.

       The lc_unshare() function returns no value, and preserves errno.

ERRORS

       ENOTSUP
              lc_share() is not supported with your current configuration. This error occurs when
              the librecast library is built without MLD support.

       ENOMEM Not enough space/cannot allocate memory (POSIX.1-2001).

       EACCES Permission to create a socket of the specified type and/or protocol is denied.

NOTES

       lc_share  uses MLD snooping from libmld to detect which multicast groups are active, which
       uses  a  raw  socket.  On  Linux,  creating  a  raw  socket  requires  CAP_NET_RAW.    See
       Capabilities(7).  On *BSD the creation of a raw socket is restricted to the superuser.  An
       application can drop these privileges after calling lc_share.

       To restrict syncing to a particular network  interface,  call  lc_ctx_ifx(3)  to  set  the
       default interface for the Librecast context before calling the appropriate sync function.

SEE ALSO

       lc_ctx_new(3), lc_ctx_ifx(3), mdex_init(3), mdex_get(3), mdex_put(3), mdex_del(3), lcrq(7)