[vlc-devel] [PATCH 5/7] Implement mDNS services advertisement submodule
Roland Bewick
roland.bewick at gmail.com
Thu Jul 25 08:03:59 CEST 2019
On 24/07/2019 11:27 PM, Rémi Denis-Courmont wrote:
> Le keskiviikkona 24. heinäkuuta 2019, 18.43.48 EEST Roland Bewick a écrit :
>> This module will launch an mdns advertisement server and listen for
>> discovery requests of the _vlc._tcp service type, making it possible to
>> resolve the VLC web interface from the vlc.local domain ---
>> modules/services_discovery/microdns.c | 310
>> +++++++++++++++++++++++++++++----- 1 file changed, 268 insertions(+), 42
>> deletions(-)
>>
>> diff --git a/modules/services_discovery/microdns.c
>> b/modules/services_discovery/microdns.c index e9ff0c6380..c460126b58 100644
>> --- a/modules/services_discovery/microdns.c
>> +++ b/modules/services_discovery/microdns.c
>> @@ -33,9 +33,22 @@
>> #include <vlc_modules.h>
>> #include <vlc_services_discovery.h>
>> #include <vlc_renderer_discovery.h>
>> +#include <vlc_services_advertisement.h>
>>
>> #include <microdns/microdns.h>
>>
>> +
>> +/*
>> + * mDNS service announcement configuration
>> + */
>> +
>> +/* This will point to the IP address and port of our running VLC interface
>> */ +#define SA_DOMAIN "vlc.local"
>> +/* respond to PTR query of this type from mDNS clients */
>> +#define SA_SERVICE_TYPE_DOMAIN "_vlc._tcp.local"
>> +/* link service type to our domain name (vlc.local) and instance name (VLC)
>> */ +#define SA_SERVICE_TYPE_LINK "vlc VLC._vlc._tcp.local"
>> +
>> static int OpenSD( vlc_object_t * );
>> static void CloseSD( vlc_object_t * );
>> static int OpenRD( vlc_object_t * );
>> @@ -97,16 +110,28 @@ static const struct
>> };
>> #define NB_PROTOCOLS (sizeof(protocols) / sizeof(*protocols))
>>
>> -struct discovery_sys
>> +struct microdns_sys_common
>> {
>> vlc_thread_t thread;
>> atomic_bool stop;
>> struct mdns_ctx * p_microdns;
>> +};
>> +
>> +struct discovery_sys
>> +{
>> + struct microdns_sys_common *p_sys_common;
>> const char * ppsz_service_names[NB_PROTOCOLS];
>> unsigned int i_nb_service_names;
>> vlc_array_t items;
>> };
>>
>> +struct advertisement_sys
>> +{
>> + struct microdns_sys_common *p_sys_common;
>> + int i_http_port;
>> + char *psz_http_host;
>> +};
>> +
>> struct item
>> {
>> char * psz_uri;
>> @@ -438,7 +463,7 @@ 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;
>>
>> - if( atomic_load( &p_sys->stop ) )
>> + if( atomic_load( &p_sys->p_sys_common->stop ) )
>> return true;
>> else
>> {
>> @@ -453,7 +478,7 @@ RunSD( void *p_this )
>> services_discovery_t *p_sd = ( services_discovery_t* )p_this;
>> struct discovery_sys *p_sys = p_sd->p_sys;
>>
>> - int i_status = mdns_listen( p_sys->p_microdns,
>> + int i_status = mdns_listen( p_sys->p_sys_common->p_microdns,
>> p_sys->ppsz_service_names,
>> p_sys->i_nb_service_names,
>> RR_PTR, SEC_FROM_VLC_TICK(LISTEN_INTERVAL),
>> @@ -550,7 +575,7 @@ stop_rd_cb( void *p_this )
>> vlc_renderer_discovery_t *p_rd = p_this;
>> struct discovery_sys *p_sys = p_rd->p_sys;
>>
>> - if( atomic_load( &p_sys->stop ) )
>> + if( atomic_load( &p_sys->p_sys_common->stop ) )
>> return true;
>> else
>> {
>> @@ -565,7 +590,7 @@ RunRD( void *p_this )
>> vlc_renderer_discovery_t *p_rd = p_this;
>> struct discovery_sys *p_sys = p_rd->p_sys;
>>
>> - int i_status = mdns_listen( p_sys->p_microdns,
>> + int i_status = mdns_listen( p_sys->p_sys_common->p_microdns,
>> p_sys->ppsz_service_names,
>> p_sys->i_nb_service_names,
>> RR_PTR, SEC_FROM_VLC_TICK(LISTEN_INTERVAL),
>> @@ -577,62 +602,205 @@ 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 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 advertisement_sys *p_sys = p_sa->p_sys;
>> + struct mdns_ctx *ctx = p_sys->p_sys_common->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;
>> }
>>
>> - if( p_sys->i_nb_service_names == 0 )
>> + /*
>> + * 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 */
> You really should use IPv6LL first and either ignore IPv4 or use it only as
> fallbacka these days. Apple HomeKit and most other recent frameworks in that
> field work that way, AFAIK.
The existing mdns modules only listen on IPv4 (service discovery and
renderer discovery).
I'll have a look into switching services advertisement to ipv6.
Thanks
>
>> +
>> + 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++)
>> {
>> - msg_Err( p_obj, "no services found" );
>> - goto error;
>> + answers[i].rr_class = RR_IN;
>> + answers[i].ttl = 120;
>> +
>> + if (i + 1 < hdr.num_ans_rr)
>> + answers[i].next = &answers[i + 1];
>> }
>> - 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" );
>> +
>> + /* RR_PTR */
>> + char *ptr_name = strdup( SA_SERVICE_TYPE_DOMAIN );
>> + char *ptr_domain = strdup( SA_SERVICE_TYPE_LINK );
>> + answers[0].type = RR_PTR;
>> + answers[0].name = ptr_name;
>> + answers[0].data.PTR.domain = ptr_domain;
>> +
>> + /* RR_TXT (currently empty) */
>> + char *txt_name = strdup( SA_SERVICE_TYPE_LINK );
>> + answers[1].type = RR_TXT;
>> + answers[1].name = txt_name;
>> +
>> + /* RR_SRV */
>> + char *srv_name = strdup( SA_SERVICE_TYPE_LINK );
>> + char *srv_target = strdup( SA_DOMAIN );
>> + answers[2].type = RR_SRV;
>> + answers[2].name = srv_name;
>> + answers[2].data.SRV.port = p_sys->i_http_port;
>> + answers[2].data.SRV.priority = 0;
>> + answers[2].data.SRV.weight = 0;
>> + answers[2].data.SRV.target = srv_target;
>> +
>> + /* RR_A */
>> + char *a_name = strdup( SA_DOMAIN );
>> + answers[3].type = RR_A;
>> + answers[3].name = a_name;
>> + sprintf( answers[3].data.A.addr_str, "%s", p_sys->psz_http_host );
>> + inet_pton( AF_INET, answers[3].data.A.addr_str, &answers[3].data.A.addr
>> ); +
>> + mdns_entries_send( ctx, &hdr, answers );
>> +
>> + free( ptr_name );
>> + free( ptr_domain );
>> + free( txt_name );
>> + free( srv_name );
>> + free( srv_target );
>> + free( a_name );
>> +}
>> +
>> +static bool
>> +stop_sa_cb( void *cbarg )
>> +{
>> + services_advertisement_t *p_sa = ( services_advertisement_t* )cbarg;
>> + struct advertisement_sys *p_sys = p_sa->p_sys;
>> +
>> + return atomic_load( &p_sys->p_sys_common->stop );
>> +}
>> +
>> +static void *
>> +RunSA( void *p_this )
>> +{
>> + services_advertisement_t *p_sa = ( services_advertisement_t* )p_this;
>> + struct advertisement_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_sys_common->p_microdns,
>> + SA_SERVICE_TYPE_DOMAIN,
>> + 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_sys_common->p_microdns, stop_sa_cb,
>> p_sa); +
>> + return NULL;
>> +}
>> +
>> +static void
>> +CleanCommon( struct microdns_sys_common *p_sys_common )
>> +{
>> + if ( p_sys_common->p_microdns )
>> + mdns_destroy( p_sys_common->p_microdns );
>> + free( p_sys_common );
>> +}
>> +
>> +static void
>> +CleanDiscoveryCommon( struct discovery_sys *p_sys )
>> +{
>> + items_clear( p_sys );
>> + CleanCommon( p_sys->p_sys_common );
>> + free( p_sys );
>> +}
>> +
>> +static void
>> +CleanAdvertisementCommon( struct advertisement_sys *p_sys )
>> +{
>> + free(p_sys->psz_http_host);
>> + CleanCommon( p_sys->p_sys_common );
>> + free( p_sys );
>> +}
>> +
>> +static void CloseCommon( struct microdns_sys_common *p_sys_common )
>> +{
>> + atomic_store( &p_sys_common->stop, true );
>> + vlc_join( p_sys_common->thread, NULL );
>> +}
>> +
>> +static int
>> +OpenCommon( vlc_object_t *p_obj, struct microdns_sys_common *p_sys_common,
>> + void *(*entry)(void *) )
>> +{
>> + int i_ret = VLC_EGENERIC;
>> + atomic_init( &p_sys_common->stop, false );
>> +
>> + int i_status;
>> + if( ( i_status = mdns_init( &p_sys_common->p_microdns, MDNS_ADDR_IPV4,
>> 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_common->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_common );
>> return i_ret;
>> }
>>
>> -static void
>> -CleanCommon( struct discovery_sys *p_sys )
>> +static int OpenDiscoveryCommon( vlc_object_t *p_obj, struct discovery_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;
>>
>> - items_clear( p_sys );
>> - mdns_destroy( p_sys->p_microdns );
>> - free( p_sys );
>> + vlc_array_init( &p_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 )
>> + p_sys->ppsz_service_names[p_sys->i_nb_service_names++] =
>> + protocols[i].psz_service_name;
>> + }
>> + if( p_sys->i_nb_service_names == 0 )
>> + {
>> + msg_Err( p_obj, "no services found" );
>> + goto error;
>> + }
>> + 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" );
>> +
>> + return OpenCommon( p_obj, p_sys->p_sys_common, entry );
>> +error:
>> + CleanCommon( p_sys->p_sys_common );
>> + return i_ret;
>> }
>>
>> static int
>> @@ -643,12 +811,19 @@ OpenSD( vlc_object_t *p_obj )
>> struct discovery_sys *p_sys = calloc( 1, sizeof(struct discovery_sys)
>> ); if( !p_sys )
>> return VLC_ENOMEM;
>> + p_sys->p_sys_common = calloc( 1, sizeof(struct microdns_sys_common) );
>> + if( !p_sys->p_sys_common )
>> + {
>> + free( p_sys );
>> + return VLC_ENOMEM;
>> + }
>> +
>> p_sd->p_sys = p_sys;
>>
>> 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
>> @@ -657,7 +832,8 @@ 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;
>>
>> - CleanCommon( p_sys );
>> + CloseCommon( p_sys->p_sys_common );
>> + CleanDiscoveryCommon( p_sys );
>> }
>>
>> static int
>> @@ -668,11 +844,18 @@ OpenRD( vlc_object_t *p_obj )
>> struct discovery_sys *p_sys = calloc( 1, sizeof(struct discovery_sys)
>> ); if( !p_sys )
>> return VLC_ENOMEM;
>> + p_sys->p_sys_common = calloc( 1, sizeof(struct microdns_sys_common) );
>> + if( !p_sys->p_sys_common )
>> + {
>> + free( 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
>> @@ -681,18 +864,61 @@ 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;
>>
>> - CleanCommon( p_sys );
>> + CloseCommon( p_sys->p_sys_common );
>> + CleanDiscoveryCommon( p_sys );
>> +}
>> +
>> +static char * detect_ip_address()
>> +{
>> + return strdup("127.0.0.1"); /* TODO: actually detect ip address */
>> }
>>
>> static int
>> OpenSA( vlc_object_t *p_obj )
>> {
>> - msg_Dbg(p_obj, "TODO: Open service advertisement module");
>> - return VLC_SUCCESS;
>> + services_advertisement_t *p_sa = (services_advertisement_t *)p_obj;
>> +
>> + struct advertisement_sys *p_sys = calloc( 1, sizeof(struct
>> advertisement_sys) ); + if( !p_sys )
>> + return VLC_ENOMEM;
>> + p_sys->p_sys_common = calloc( 1, sizeof(struct microdns_sys_common) );
>> + if( !p_sys->p_sys_common )
>> + {
>> + free( p_sys );
>> + return VLC_ENOMEM;
>> + }
>> +
>> + p_sys->i_http_port = var_InheritInteger( p_obj, "http-port" ); /* 8080
>> if unset */ + p_sys->psz_http_host = var_InheritString( p_obj,
>> "http-host" ); /* null if unset */ +
>> + if ( p_sys->psz_http_host && strlen( p_sys->psz_http_host ) >
>> INET_ADDRSTRLEN ) + {
>> + msg_Err( p_obj, "http-host is not a valid IPv4 address: %s",
>> p_sys->psz_http_host ); + free( p_sys->psz_http_host );
>> + p_sys->psz_http_host = NULL;
>> + }
>> +
>> + if( !p_sys->psz_http_host )
>> + {
>> + msg_Dbg( p_obj, "http-host unset, detecting local IP address...");
>> + p_sys->psz_http_host = detect_ip_address();
>> + msg_Dbg( p_obj, "chose local IP address: %s",
>> p_sys->psz_http_host); + }
>> +
>> + p_sa->p_sys = p_sys;
>> +
>> + p_sa->description = _("mDNS Network Advertisement");
>> + config_ChainParse( p_sa, CFG_PREFIX, ppsz_options, p_sa->p_cfg );
>> +
>> + return OpenCommon( p_obj, p_sys->p_sys_common, RunSA );
>> }
>>
>> static void
>> CloseSA( vlc_object_t *p_this )
>> {
>> - msg_Dbg(p_this, "TODO: Close service advertisement module");
>> + services_advertisement_t *p_sa = (services_advertisement_t *) p_this;
>> + struct advertisement_sys *p_sys = p_sa->p_sys;
>> +
>> + CloseCommon( p_sys->p_sys_common );
>> + CleanAdvertisementCommon( p_sys );
>> }
>> \ No newline at end of file
>
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