[vlc-devel] [PATCH 3/3] Add microdns services_advertisement submodule

Thomas Guillem thomas at gllm.fr
Mon Sep 2 14:14:11 CEST 2019



On Mon, Sep 2, 2019, at 07:25, Roland Bewick wrote:
> ---
>  modules/services_discovery/microdns.c | 318 +++++++++++++++++++++-----
>  1 file changed, 261 insertions(+), 57 deletions(-)
> 
> diff --git a/modules/services_discovery/microdns.c 
> b/modules/services_discovery/microdns.c
> index ad0d2691f7..d5dc5bda94 100644
> --- a/modules/services_discovery/microdns.c
> +++ b/modules/services_discovery/microdns.c
> @@ -33,6 +33,7 @@
>  #include <vlc_modules.h>
>  #include <vlc_services_discovery.h>
>  #include <vlc_renderer_discovery.h>
> +#include <vlc_services_advertisement.h>
>  
>  #include <microdns/microdns.h>
>  
> @@ -40,6 +41,8 @@ static int OpenSD( vlc_object_t * );
>  static void CloseSD( vlc_object_t * );
>  static int OpenRD( vlc_object_t * );
>  static void CloseRD( vlc_object_t * );
> +static int OpenSA( vlc_object_t * );
> +static void CloseSA( vlc_object_t * );
>  
>  VLC_SD_PROBE_HELPER( "microdns", N_("mDNS Network Discovery"), SD_CAT_LAN )
>  VLC_RD_PROBE_HELPER( "microdns_renderer", "mDNS renderer Discovery" )
> @@ -69,6 +72,14 @@ vlc_module_begin()
>          set_callbacks( OpenRD, CloseRD )
>          add_shortcut( "mdns_renderer", "microdns_renderer" )
>          VLC_RD_PROBE_SUBMODULE
> +    add_submodule() \
> +        set_description( N_( "mDNS Services Advertisement" ) )
> +        set_category( CAT_ADVANCED )
> +        set_subcategory( SUBCAT_ADVANCED_NETWORK )
> +        set_capability( "services_advertisement", 0 )
> +        set_callbacks( OpenSA, CloseSA )
> +        add_shortcut( "mdns", "microdns" )
> +        VLC_RD_PROBE_SUBMODULE
>  vlc_module_end ()
>  
>  static const struct
> @@ -87,16 +98,37 @@ static const struct
>  };
>  #define NB_PROTOCOLS (sizeof(protocols) / sizeof(*protocols))
>  
> +/* 
> + * Services advertisement configuration
> + */
> +char sa_domain_name[] = "vlc.local"; /* Announce our service on this 
> domain name*/
> +char sa_service_type[] = "_vlc._tcp.local"; /* respond to PTR query of 
> this type */
> +char sa_service_type_link[] = "vlc VLC._vlc._tcp.local"; /* link 
> service type to domain */

These 3 char * should be const and static.

> +
>  struct discovery_sys
>  {
> -    vlc_thread_t        thread;
> -    atomic_bool         stop;
> -    struct mdns_ctx *   p_microdns;
>      const char *        ppsz_service_names[NB_PROTOCOLS];
>      unsigned int        i_nb_service_names;
>      vlc_array_t         items;
>  };
>  
> +struct advertisement_sys
> +{
> +    int i_http_port;
> +};
> +
> +struct microdns_sys
> +{
> +    vlc_thread_t        thread;
> +    atomic_bool         stop;
> +    struct mdns_ctx *   p_microdns;
> +    union
> +    {
> +        struct discovery_sys discovery_sys;
> +        struct advertisement_sys advertisement_sys;
> +    };
> +};
> +
>  struct item
>  {
>      char *              psz_uri;
> @@ -383,7 +415,7 @@ static void
>  new_entries_sd_cb( void *p_this, int i_status, const struct rr_entry 
> *p_entries )
>  {
>      services_discovery_t *p_sd = (services_discovery_t *)p_this;
> -    struct discovery_sys *p_sys = p_sd->p_sys;
> +    struct microdns_sys *p_sys = p_sd->p_sys;

If you do

struct microdns_sys *p_mdns_sys = p_sd->p_sys;
struct discovery_sys *p_sys = p_mdns_sys->p_sys;

You won't have to modify every access of discovery_sys. The diff will be smaller and easier to read.


>      if( i_status < 0 )
>      {
>          print_error( VLC_OBJECT( p_sd ), "entry callback", i_status );
> @@ -408,12 +440,12 @@ new_entries_sd_cb( void *p_this, int i_status, 
> const struct rr_entry *p_entries
>          if( psz_uri == NULL )
>              break;
>  
> -        if( items_exists( p_sys, psz_uri ) )
> +        if( items_exists( &p_sys->discovery_sys, psz_uri ) )

>          {
>              free( psz_uri );
>              continue;
>          }
> -        items_add_input( p_sys, p_sd, psz_uri, p_srv->psz_device_name 
> );
> +        items_add_input( &p_sys->discovery_sys, p_sd, psz_uri, 
> p_srv->psz_device_name );
>      }
>  
>      for( unsigned int i = 0; i < i_nb_srv; ++i )
> @@ -426,13 +458,13 @@ static bool
>  stop_sd_cb( void *p_this )
>  {
>      services_discovery_t *p_sd = ( services_discovery_t* )p_this;
> -    struct discovery_sys *p_sys = p_sd->p_sys;
> +    struct microdns_sys *p_sys = p_sd->p_sys;
>  
>      if( atomic_load( &p_sys->stop ) )
>          return true;
>      else
>      {
> -        items_timeout( p_sys, p_sd, NULL );
> +        items_timeout( &p_sys->discovery_sys, p_sd, NULL );
>          return false;
>      }
>  }
> @@ -441,11 +473,11 @@ static void *
>  RunSD( void *p_this )
>  {
>      services_discovery_t *p_sd = ( services_discovery_t* )p_this;
> -    struct discovery_sys *p_sys = p_sd->p_sys;
> +    struct microdns_sys *p_sys = p_sd->p_sys;
>  
>      int i_status = mdns_listen( p_sys->p_microdns,
> -                                p_sys->ppsz_service_names,
> -                                p_sys->i_nb_service_names,
> +                                p_sys->discovery_sys.ppsz_service_names,
> +                                p_sys->discovery_sys.i_nb_service_names,
>                                  RR_PTR, SEC_FROM_VLC_TICK(LISTEN_INTERVAL),
>                                  stop_sd_cb, new_entries_sd_cb, p_sd );
>  
> @@ -459,7 +491,7 @@ static void
>  new_entries_rd_cb( void *p_this, int i_status, const struct rr_entry 
> *p_entries )
>  {
>      vlc_renderer_discovery_t *p_rd = (vlc_renderer_discovery_t 
> *)p_this;
> -    struct discovery_sys *p_sys = p_rd->p_sys;
> +    struct microdns_sys *p_sys = p_rd->p_sys;
>      if( i_status < 0 )
>      {
>          print_error( VLC_OBJECT( p_rd ), "entry callback", i_status );
> @@ -506,7 +538,7 @@ new_entries_rd_cb( void *p_this, int i_status, 
> const struct rr_entry *p_entries
>          if( psz_uri == NULL )
>              break;
>  
> -        if( items_exists( p_sys, psz_uri ) )
> +        if( items_exists( &p_sys->discovery_sys, psz_uri ) )
>          {
>              free( psz_uri );
>              continue;
> @@ -523,8 +555,8 @@ new_entries_rd_cb( void *p_this, int i_status, 
> const struct rr_entry *p_entries
>          if( strcmp( p_srv->psz_protocol, "chromecast" ) == 0)
>              psz_demux_filter = "cc_demux";
>  
> -        items_add_renderer( p_sys, p_rd, p_srv->psz_device_name, 
> psz_uri,
> -                            psz_demux_filter, psz_icon_uri,
> +        items_add_renderer( &p_sys->discovery_sys, p_rd, 
> p_srv->psz_device_name,
> +                            psz_uri, psz_demux_filter, psz_icon_uri,
>                              p_srv->i_renderer_flags );
>          free(psz_icon_uri);
>      }
> @@ -538,13 +570,13 @@ static bool
>  stop_rd_cb( void *p_this )
>  {
>      vlc_renderer_discovery_t *p_rd = p_this;
> -    struct discovery_sys *p_sys = p_rd->p_sys;
> +    struct microdns_sys *p_sys = p_rd->p_sys;
>  
>      if( atomic_load( &p_sys->stop ) )
>          return true;
>      else
>      {
> -        items_timeout( p_sys, NULL, p_rd );
> +        items_timeout( &p_sys->discovery_sys, NULL, p_rd );
>          return false;
>      }
>  }
> @@ -553,11 +585,11 @@ static void *
>  RunRD( void *p_this )
>  {
>      vlc_renderer_discovery_t *p_rd = p_this;
> -    struct discovery_sys *p_sys = p_rd->p_sys;
> +    struct microdns_sys *p_sys = p_rd->p_sys;
>  
>      int i_status = mdns_listen( p_sys->p_microdns,
> -                                p_sys->ppsz_service_names,
> -                                p_sys->i_nb_service_names,
> +                                p_sys->discovery_sys.ppsz_service_names,
> +                                p_sys->discovery_sys.i_nb_service_names,
>                                  RR_PTR, SEC_FROM_VLC_TICK(LISTEN_INTERVAL),
>                                  stop_rd_cb, new_entries_rd_cb, p_rd );
>  
> @@ -567,62 +599,195 @@ RunRD( void *p_this )
>      return NULL;
>  }
>  
> -static int
> -OpenCommon( vlc_object_t *p_obj, struct discovery_sys *p_sys, bool b_renderer )
> +static void
> +request_sa_callback(void *cbarg, int r, const struct mdns_ip *mdns_ip,
> +                    const struct rr_entry *entry)
>  {
> -    int i_ret = VLC_EGENERIC;
> -    atomic_init( &p_sys->stop, false );
> -    vlc_array_init( &p_sys->items );
> +    VLC_UNUSED( r );  /* result code from mdns_recv */
>  
> -    /* Listen to protocols that are handled by VLC */
> -    for( unsigned int i = 0; i < NB_PROTOCOLS; ++i )
> +    services_advertisement_t *p_sa = ( services_advertisement_t* 
> )cbarg;
> +    struct microdns_sys *p_sys = p_sa->p_sys;
> +    struct mdns_ctx *ctx = p_sys->p_microdns;
> +    struct mdns_hdr hdr = {0};  /* response header */
> +
> +    if( entry->type != RR_PTR || entry->rr_class != RR_IN )
>      {
> -        if( protocols[i].b_renderer == b_renderer )
> -            p_sys->ppsz_service_names[p_sys->i_nb_service_names++] =
> -                protocols[i].psz_service_name;
> +        msg_Dbg( VLC_OBJECT( p_sa ),
> +                 "mDNS-SA: Skipped unsupported request type: %d class: 
> %d\n",
> +                 entry->type,
> +                 entry->rr_class );
> +        return;
> +    }
> +
> +    /*
> +     * When we receive a PTR record (question) from an mDNS client we 
> need to
> +     * answer with four record types that will allow our domain name 
> (vlc.local)
> +     * to resolve the IP address and port we are hosting the VLC 
> interface on.
> +     * 
> +     * PTR: point service type (_vlc._tcp._local) to local domain
> +     * TXT: provide additional information (HTTP server root directory 
> etc.) 
> +     * SRV: provide server information (port number etc.)
> +     * A: link local domain to IP address
> +     */
> +
> +    struct rr_entry answers[4] = {0};  /* PTR, TXT, SRV, A */
> +
> +    hdr.flags |= FLAG_QR;
> +    hdr.flags |= FLAG_AA;
> +
> +    hdr.num_ans_rr = sizeof( answers ) / sizeof( answers[0] );
> +
> +    for( int i = 0; i < hdr.num_ans_rr; i++ )
> +    {
> +            answers[i].rr_class = RR_IN;
> +            answers[i].ttl      = 120;
> +
> +            if (i + 1 < hdr.num_ans_rr)
> +                    answers[i].next = &answers[i + 1];
>      }
>  
> -    if( p_sys->i_nb_service_names == 0 )
> +    // RR_PTR: point service type to local domain and instance name 
> (VLC)
> +    answers[0].type     = RR_PTR;
> +    answers[0].name     = sa_service_type;
> +    answers[0].data.PTR.domain = sa_service_type_link;
> +
> +    // RR_TXT: provide additional information (HTTP server root 
> directory etc.)
> +    answers[1].type     = RR_TXT;
> +    answers[1].name     = sa_service_type_link;
> +    
> +    // RR_SRV: provide info about the service we're announcing (port 
> no, etc.)
> +    answers[2].type     = RR_SRV;
> +    answers[2].name     = sa_service_type_link;
> +    answers[2].data.SRV.port = p_sys->advertisement_sys.i_http_port;
> +    answers[2].data.SRV.priority = 0;
> +    answers[2].data.SRV.weight = 0;
> +    answers[2].data.SRV.target = sa_domain_name;
> +    
> +    // RR_A/AAAA: link .local domain to IP address
> +    answers[3].name     = sa_domain_name;
> +    if (mdns_ip->family == AF_INET)
>      {
> -        msg_Err( p_obj, "no services found" );
> -        goto error;
> +            answers[3].type     = RR_A;
> +            memcpy(&answers[3].data.A.addr, &mdns_ip->ipv4, 
> +                    sizeof(answers[3].data.A.addr));
>      }
> -    for( unsigned int i = 0; i < p_sys->i_nb_service_names; ++i )
> -        msg_Dbg( p_obj, "mDNS: listening to %s %s", 
> p_sys->ppsz_service_names[i],
> -                 b_renderer ? "renderer" : "service" );
> +    else
> +    {
> +            answers[3].type     = RR_AAAA;
> +            memcpy(&answers[3].data.AAAA.addr, &mdns_ip->ipv6, 
> +                    sizeof(answers[3].data.AAAA.addr));
> +    }
> +
> +    mdns_entries_send(ctx, &hdr, answers);
> +}
> +
> +static bool
> +stop_sa_cb( void *cbarg )
> +{
> +    services_advertisement_t *p_sa = ( services_advertisement_t* 
> )cbarg;
> +    struct microdns_sys *p_sys = p_sa->p_sys;
> +
> +    return atomic_load( &p_sys->stop );
> +}
> +
> +static void *
> +RunSA( void *p_this )
> +{
> +    services_advertisement_t *p_sa = ( services_advertisement_t* 
> )p_this;
> +    struct microdns_sys *p_sys = p_sa->p_sys;
>  
>      int i_status;
> -    if( ( i_status = mdns_init( &p_sys->p_microdns, MDNS_ADDR_IPV4,
> +
> +    i_status = mdns_announce( p_sys->p_microdns,
> +                              sa_service_type,
> +                              RR_PTR,
> +                              request_sa_callback,
> +                              p_sa);
> +
> +    if( i_status < 0 )
> +        print_error( VLC_OBJECT( p_sa ), "announce", i_status );
> +    
> +    i_status = mdns_serve(p_sys->p_microdns, stop_sa_cb, p_sa);
> +
> +    return NULL;
> +}
> +
> +static void
> +CleanCommon( struct microdns_sys *p_sys )
> +{
> +    if ( p_sys->p_microdns )
> +        mdns_destroy( p_sys->p_microdns );
> +    free( p_sys );
> +}
> +
> +static void
> +CleanDiscoveryCommon( struct microdns_sys *p_sys )
> +{
> +    items_clear( &p_sys->discovery_sys );
> +    CleanCommon( p_sys );
> +}
> +
> +
> +static void CloseCommon( struct microdns_sys *p_sys )
> +{
> +    atomic_store( &p_sys->stop, true );
> +    vlc_join( p_sys->thread, NULL );
> +}
> +
> +static int
> +OpenCommon( vlc_object_t *p_obj, struct microdns_sys *p_sys,
> +            const char *mdns_addr, void *(*entry)(void *) )
> +{
> +    int i_ret = VLC_EGENERIC;
> +    atomic_init( &p_sys->stop, false );
> +
> +    int i_status;
> +    if( ( i_status = mdns_init( &p_sys->p_microdns, mdns_addr,
>                                  MDNS_PORT ) ) < 0 )
>      {
>          print_error( p_obj, "init", i_status );
>          goto error;
>      }
>  
> -    if( vlc_clone( &p_sys->thread, b_renderer ? RunRD : RunSD, p_obj,
> -                   VLC_THREAD_PRIORITY_LOW) )
> +    if( vlc_clone( &p_sys->thread, entry, p_obj, VLC_THREAD_PRIORITY_LOW) )
>      {
> -        msg_Err( p_obj, "Can't run the lookup thread" );
> +        msg_Err( p_obj, "Can't run the mdns thread");
>          goto error;
>      }
>  
>      return VLC_SUCCESS;
>  error:
> -    if( p_sys->p_microdns != NULL )
> -        mdns_destroy( p_sys->p_microdns );
> -    free( p_sys );
> +    CleanCommon( p_sys );
>      return i_ret;
>  }
>  
> -static void
> -CleanCommon( struct discovery_sys *p_sys )
> +static int OpenDiscoveryCommon( vlc_object_t *p_obj, struct 
> microdns_sys *p_sys,
> +                               bool b_renderer, void *(*entry)(void *) 
> )
>  {
> -    atomic_store( &p_sys->stop, true );
> -    vlc_join( p_sys->thread, NULL );
> +    int i_ret = VLC_EGENERIC;
> +    struct discovery_sys *discovery_sys = &p_sys->discovery_sys;
>  
> -    items_clear( p_sys );
> -    mdns_destroy( p_sys->p_microdns );
> -    free( p_sys );
> +    vlc_array_init( &discovery_sys->items );
> +    /* Listen to protocols that are handled by VLC */
> +    for( unsigned int i = 0; i < NB_PROTOCOLS; ++i )
> +    {
> +        if( protocols[i].b_renderer == b_renderer )
> +            
> discovery_sys->ppsz_service_names[discovery_sys->i_nb_service_names++] =
> +                protocols[i].psz_service_name;
> +    }
> +    if( discovery_sys->i_nb_service_names == 0 )
> +    {
> +        msg_Err( p_obj, "no services found" );
> +        goto error;
> +    }
> +    for( unsigned int i = 0; i < discovery_sys->i_nb_service_names; 
> ++i )
> +        msg_Dbg( p_obj, "mDNS: listening to %s %s", 
> discovery_sys->ppsz_service_names[i],
> +                b_renderer ? "renderer" : "service" );
> +    
> +    return OpenCommon( p_obj, p_sys, MDNS_ADDR_IPV4, entry );
> +error:
> +    CleanCommon( p_sys );
> +    return i_ret;
>  }
>  
>  static int
> @@ -630,7 +795,7 @@ OpenSD( vlc_object_t *p_obj )
>  {
>      services_discovery_t *p_sd = (services_discovery_t *)p_obj;
>  
> -    struct discovery_sys *p_sys = calloc( 1, sizeof(struct discovery_sys) );
> +    struct microdns_sys *p_sys = calloc( 1, sizeof(struct microdns_sys) );
>      if( !p_sys )
>          return VLC_ENOMEM;
>      p_sd->p_sys = p_sys;
> @@ -638,16 +803,17 @@ OpenSD( vlc_object_t *p_obj )
>      p_sd->description = _("mDNS Network Discovery");
>      config_ChainParse( p_sd, CFG_PREFIX, ppsz_options, p_sd->p_cfg );
>  
> -    return OpenCommon( p_obj, p_sys, false );
> +    return OpenDiscoveryCommon( p_obj, p_sys, false, RunSD );
>  }
>  
>  static void
>  CloseSD( vlc_object_t *p_this )
>  {
>      services_discovery_t *p_sd = (services_discovery_t *) p_this;
> -    struct discovery_sys *p_sys = p_sd->p_sys;
> +    struct microdns_sys *p_sys = p_sd->p_sys;
>  
> -    CleanCommon( p_sys );
> +    CloseCommon( p_sys );
> +    CleanDiscoveryCommon( p_sys );
>  }
>  
>  static int
> @@ -655,21 +821,59 @@ OpenRD( vlc_object_t *p_obj )
>  {
>      vlc_renderer_discovery_t *p_rd = (vlc_renderer_discovery_t *)p_obj;
>  
> -    struct discovery_sys *p_sys = calloc( 1, sizeof(struct discovery_sys) );
> +    struct microdns_sys *p_sys = calloc( 1, sizeof(struct microdns_sys) );
>      if( !p_sys )
>          return VLC_ENOMEM;
>      p_rd->p_sys = p_sys;
>  
>      config_ChainParse( p_rd, CFG_PREFIX, ppsz_options, p_rd->p_cfg );
>  
> -    return OpenCommon( p_obj, p_sys, true );
> +    return OpenDiscoveryCommon( p_obj, p_sys, true, RunRD );
>  }
>  
>  static void
>  CloseRD( vlc_object_t *p_this )
>  {
>      vlc_renderer_discovery_t *p_rd = (vlc_renderer_discovery_t *) p_this;
> -    struct discovery_sys *p_sys = p_rd->p_sys;
> +    struct microdns_sys *p_sys = p_rd->p_sys;
> +
> +    CloseCommon( p_sys );
> +    CleanDiscoveryCommon( p_sys );
> +}
> +
> +static int
> +OpenSA( vlc_object_t *p_obj )
> +{
> +    services_advertisement_t *p_sa = (services_advertisement_t *)p_obj;
> +
> +    struct microdns_sys *p_sys = calloc( 1, sizeof(struct microdns_sys) );
> +    if( !p_sys )
> +        return VLC_ENOMEM;
> +
> +    p_sa->p_sys = p_sys;
> +    config_ChainParse( p_sa, CFG_PREFIX, ppsz_options, p_sa->p_cfg );
> +
> +    p_sys->advertisement_sys.i_http_port = var_InheritInteger( 
> +        p_obj, "http-port" ); /* 8080 if unset */
> +    char *psz_address_family = var_InheritString( 
> +        p_obj, "services-advertisement-address-family" ); /* v6 if unset */
> +
> +
> +    p_sa->description = _("mDNS Network Advertisement");
> +
> +    const char *mdns_addr = MDNS_ADDR_IPV6;
> +    if( strcmp( psz_address_family, "v4" ) == 0 )
> +        mdns_addr = MDNS_ADDR_IPV4;
> +    
> +    return OpenCommon( p_obj, p_sys, mdns_addr, RunSA );

YOu should free (psz_address_family).

> +}
> +
> +static void
> +CloseSA( vlc_object_t *p_this )
> +{
> +    services_advertisement_t *p_sa = (services_advertisement_t *) p_this;
> +    struct microdns_sys *p_sys = p_sa->p_sys;
>  
> +    CloseCommon( p_sys );
>      CleanCommon( p_sys );
>  }
> -- 
> 2.17.1
> 
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