sap.c

VLC Player Source Code

/*****************************************************************************
 * sap.c :  SAP interface module
 *****************************************************************************
 * Copyright (C) 2004-2005 the VideoLAN team
 * Copyright © 2007 Rémi Denis-Courmont
 * $Id: ec84aa964e2cbc2b4197e3fdc7ac45ef9ee9379d $
 *
 * Authors: Clément Stenac <[e-mail]>
 *          Rémi Denis-Courmont
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Includes
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <assert.h>

#include <vlc_demux.h>
#include <vlc_services_discovery.h>

#include <vlc_network.h>
#include <vlc_charset.h>

#include <ctype.h>
#include <errno.h>

#ifdef HAVE_UNISTD_H
#    include <unistd.h>
#endif
#ifdef HAVE_SYS_TIME_H
#    include <sys/time.h>
#endif
#ifdef HAVE_POLL
# include <poll.h>
#endif

#ifdef HAVE_ZLIB_H
#   include <zlib.h>
#endif

#ifndef WIN32
#   include <net/if.h>
#endif

/************************************************************************
 * Macros and definitions
 ************************************************************************/

#define MAX_LINE_LENGTH 256

/* SAP is always on that port */
#define SAP_PORT 9875
/* Global-scope SAP address */
#define SAP_V4_GLOBAL_ADDRESS   "224.2.127.254"
/* Organization-local SAP address */
#define SAP_V4_ORG_ADDRESS      "239.195.255.255"
/* Local (smallest non-link-local scope) SAP address */
#define SAP_V4_LOCAL_ADDRESS    "239.255.255.255"
/* Link-local SAP address */
#define SAP_V4_LINK_ADDRESS     "224.0.0.255"
#define ADD_SESSION 1

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
#define SAP_ADDR_TEXT N_( "SAP multicast address" )
#define SAP_ADDR_LONGTEXT N_( "The SAP module normally chooses itself the " \
                              "right addresses to listen to. However, you " \
                              "can specify a specific address." )
#define SAP_IPV4_TEXT N_( "IPv4 SAP" )
#define SAP_IPV4_LONGTEXT N_( \
      "Listen to IPv4 announcements on the standard addresses." )
#define SAP_IPV6_TEXT N_( "IPv6 SAP" )
#define SAP_IPV6_LONGTEXT N_( \
      "Listen to IPv6 announcements on the standard addresses." )
#define SAP_SCOPE_TEXT N_( "IPv6 SAP scope" )
#define SAP_SCOPE_LONGTEXT N_( \
       "Scope for IPv6 announcements (default is 8)." )
#define SAP_TIMEOUT_TEXT N_( "SAP timeout (seconds)" )
#define SAP_TIMEOUT_LONGTEXT N_( \
       "Delay after which SAP items get deleted if no new announcement " \
       "is received." )
#define SAP_PARSE_TEXT N_( "Try to parse the announce" )
#define SAP_PARSE_LONGTEXT N_( \
       "This enables actual parsing of the announces by the SAP module. " \
       "Otherwise, all announcements are parsed by the \"live555\" " \
       "(RTP/RTSP) module." )
#define SAP_STRICT_TEXT N_( "SAP Strict mode" )
#define SAP_STRICT_LONGTEXT N_( \
       "When this is set, the SAP parser will discard some non-compliant " \
       "announcements." )
#define SAP_CACHE_TEXT N_("Use SAP cache")
#define SAP_CACHE_LONGTEXT N_( \
       "This enables a SAP caching mechanism. " \
       "This will result in lower SAP startup time, but you could end up " \
       "with items corresponding to legacy streams." )
#define SAP_TIMESHIFT_TEXT N_("Allow timeshifting")
#define SAP_TIMESHIFT_LONGTEXT N_( "This automatically enables timeshifting " \
        "for streams discovered through SAP announcements." )

/* Callbacks */
    static int  Open ( vlc_object_t * );
    static void Close( vlc_object_t * );
    static int  OpenDemux ( vlc_object_t * );
    static void CloseDemux ( vlc_object_t * );

vlc_module_begin();
    set_shortname( N_("SAP"));
    set_description( N_("SAP Announcements") );
    set_category( CAT_PLAYLIST );
    set_subcategory( SUBCAT_PLAYLIST_SD );

    add_string( "sap-addr", NULL, NULL,
                SAP_ADDR_TEXT, SAP_ADDR_LONGTEXT, true );
    add_bool( "sap-ipv4", 1 , NULL,
               SAP_IPV4_TEXT,SAP_IPV4_LONGTEXT, true );
    add_bool( "sap-ipv6", 1 , NULL,
              SAP_IPV6_TEXT, SAP_IPV6_LONGTEXT, true );
    add_integer( "sap-timeout", 1800, NULL,
                 SAP_TIMEOUT_TEXT, SAP_TIMEOUT_LONGTEXT, true );
    add_bool( "sap-parse", 1 , NULL,
               SAP_PARSE_TEXT,SAP_PARSE_LONGTEXT, true );
    add_bool( "sap-strict", 0 , NULL,
               SAP_STRICT_TEXT,SAP_STRICT_LONGTEXT, true );
#if 0
    add_bool( "sap-cache", 0 , NULL,
               SAP_CACHE_TEXT,SAP_CACHE_LONGTEXT, true );
#endif
    add_bool( "sap-timeshift", 0 , NULL,
              SAP_TIMESHIFT_TEXT,SAP_TIMESHIFT_LONGTEXT, true );

    set_capability( "services_discovery", 0 );
    set_callbacks( Open, Close );

    add_submodule();
        set_description( N_("SDP Descriptions parser") );
        add_shortcut( "sdp" );
        set_capability( "demux", 51 );
        set_callbacks( OpenDemux, CloseDemux );
vlc_module_end();


/*****************************************************************************
 * Local structures
 *****************************************************************************/

typedef struct sdp_t sdp_t;
typedef struct attribute_t attribute_t;
typedef struct sap_announce_t sap_announce_t;


struct sdp_media_t
{
    struct sdp_t           *parent;
    char                   *fmt;
    struct sockaddr_storage addr;
    socklen_t               addrlen;
    unsigned                n_addr;
    int           i_attributes;
    attribute_t  **pp_attributes;
};


/* The structure that contains sdp information */
struct  sdp_t
{
    const char *psz_sdp;

    /* o field */
    char     username[64];
    uint64_t session_id;
    uint64_t session_version;
    unsigned orig_ip_version;
    char     orig_host[1024];

    /* s= field */
    char *psz_sessionname;

    /* old cruft */
    /* "computed" URI */
    char *psz_uri;
    int           i_media_type;

    /* a= global attributes */
    int           i_attributes;
    attribute_t  **pp_attributes;

    /* medias (well, we only support one atm) */
    unsigned            mediac;
    struct sdp_media_t *mediav;
};

struct attribute_t
{
    const char *value;
    char name[0];
};

struct sap_announce_t
{
    mtime_t i_last;
    mtime_t i_period;
    uint8_t i_period_trust;

    uint16_t    i_hash;
    uint32_t    i_source[4];

    /* SAP annnounces must only contain one SDP */
    sdp_t       *p_sdp;

    input_item_t * p_item;
};

struct services_discovery_sys_t
{
    /* Socket descriptors */
    int i_fd;
    int *pi_fd;

    /* Table of announces */
    int i_announces;
    struct sap_announce_t **pp_announces;

    /* Modes */
    bool  b_strict;
    bool  b_parse;
    bool  b_timeshift;

    int i_timeout;
};

struct demux_sys_t
{
    sdp_t *p_sdp;
};

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/


/* Main functions */
    static int Demux( demux_t *p_demux );
    static int Control( demux_t *, int, va_list );
    static void Run    ( services_discovery_t *p_sd );

/* Main parsing functions */
    static int ParseConnection( vlc_object_t *p_obj, sdp_t *p_sdp );
    static int ParseSAP( services_discovery_t *p_sd, const uint8_t *p_buffer, size_t i_read );
    static sdp_t *ParseSDP (vlc_object_t *p_sd, const char *psz_sdp);
    static sap_announce_t *CreateAnnounce( services_discovery_t *, uint16_t, sdp_t * );
    static int RemoveAnnounce( services_discovery_t *p_sd, sap_announce_t *p_announce );

/* Helper functions */
    static inline attribute_t *MakeAttribute (const char *str);
    static const char *GetAttribute (attribute_t **tab, unsigned n, const char *name);
    static inline void FreeAttribute (attribute_t *a);
    static const char *FindAttribute (const sdp_t *sdp, unsigned media,
                                      const char *name);

    static bool IsSameSession( sdp_t *p_sdp1, sdp_t *p_sdp2 );
    static int InitSocket( services_discovery_t *p_sd, const char *psz_address, int i_port );
    static int Decompress( const unsigned char *psz_src, unsigned char **_dst, int i_len );
    static void FreeSDP( sdp_t *p_sdp );

static inline int min_int( int a, int b )
{
    return a > b ? b : a;
}

/*****************************************************************************
 * Open: initialize and create stuff
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    services_discovery_t *p_sd = ( services_discovery_t* )p_this;
    services_discovery_sys_t *p_sys  = (services_discovery_sys_t *)
                                malloc( sizeof( services_discovery_sys_t ) );
    if( !p_sys )
        return VLC_ENOMEM;

    p_sys->i_timeout = var_CreateGetInteger( p_sd, "sap-timeout" );

    p_sd->pf_run = Run;
    p_sd->p_sys  = p_sys;

    p_sys->pi_fd = NULL;
    p_sys->i_fd = 0;

    p_sys->b_strict = var_CreateGetInteger( p_sd, "sap-strict");
    p_sys->b_parse = var_CreateGetInteger( p_sd, "sap-parse" );

#if 0
    if( var_CreateGetInteger( p_sd, "sap-cache" ) )
    {
        CacheLoad( p_sd );
    }
#endif

    /* Cache sap_timeshift value */
    p_sys->b_timeshift = var_CreateGetInteger( p_sd, "sap-timeshift" );

    /* Set our name */
    services_discovery_SetLocalizedName( p_sd, _("SAP") );

    p_sys->i_announces = 0;
    p_sys->pp_announces = NULL;

    return VLC_SUCCESS;
}

/*****************************************************************************
 * OpenDemux: initialize and create stuff
 *****************************************************************************/
static int OpenDemux( vlc_object_t *p_this )
{
    demux_t *p_demux = (demux_t *)p_this;
    const uint8_t *p_peek;
    char *psz_sdp = NULL;
    sdp_t *p_sdp = NULL;
    int errval = VLC_EGENERIC;
    size_t i_len;

    if( !var_CreateGetInteger( p_demux, "sap-parse" ) )
    {
        /* We want livedotcom module to parse this SDP file */
        return VLC_EGENERIC;
    }

    assert( p_demux->s ); /* this is NOT an access_demux */

    /* Probe for SDP */
    if( stream_Peek( p_demux->s, &p_peek, 7 ) < 7 )
        return VLC_EGENERIC;

    if( memcmp( p_peek, "v=0\r\no=", 7 ) && memcmp( p_peek, "v=0\no=", 6 ) )
        return VLC_EGENERIC;

    /* Gather the complete sdp file */
    for( i_len = 0, psz_sdp = NULL; i_len < 65536; )
    {
        const int i_read_max = 1024;
        char *psz_sdp_new = realloc( psz_sdp, i_len + i_read_max );
        size_t i_read;
        if( psz_sdp_new == NULL )
        {
            errval = VLC_ENOMEM;
            goto error;
        }
        psz_sdp = psz_sdp_new;

        i_read = stream_Read( p_demux->s, &psz_sdp[i_len], i_read_max );
        if( (int)i_read < 0 )
        {
            msg_Err( p_demux, "cannot read SDP" );
            goto error;
        }
        i_len += i_read;

        psz_sdp[i_len] = '\0';

        if( (int)i_read < i_read_max )
            break; // EOF
    }

    p_sdp = ParseSDP( VLC_OBJECT(p_demux), psz_sdp );

    if( !p_sdp )
    {
        msg_Warn( p_demux, "invalid SDP");
        goto error;
    }

    if( ParseConnection( VLC_OBJECT( p_demux ), p_sdp ) )
    {
        p_sdp->psz_uri = NULL;
    }
    switch (p_sdp->i_media_type)
    {   /* Should be in sync with modules/demux/rtp.c */