[vlc-devel] [PATCH 5/7] Implement mDNS services advertisement submodule
Thomas Guillem
thomas at gllm.fr
Mon Jul 29 13:19:34 CEST 2019
On Thu, Jul 25, 2019, at 08:04, Roland Bewick wrote:
>
> 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
One useless allocation here, it should be a struct microdns_sys_common, not a pointer.
Maybe, this change could be less intrusive with an union ?
> >> 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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