[vlc-devel] [PATCH 5/7] Implement mDNS services advertisement submodule
Roland Bewick
roland.bewick at gmail.com
Wed Jul 24 17:43:48 CEST 2019
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 */
+
+ 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
--
2.11.0
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