[avahi] Fix usage of searched address type (#11377)

The Avahi-based service resolver mixes two things up: - searched address type (A or AAAA record) - IP protocol version to be used for doing the query. The service browse callbacks uses the latter as the former. Consequently, if an IPv6 commissionable service is published only via IPv4 mDNS server, it can't be properly discovered.
project-chip · Nov 3, 2021 · 38fe11e · 38fe11e
1 parent 249ccbc
commit 38fe11e
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Showing 3 changed files with 23 additions and 25 deletions.
diff --git a/src/lib/dnssd/platform/Dnssd.h b/src/lib/dnssd/platform/Dnssd.h
@@ -66,7 +66,8 @@ struct DnssdService
     char mHostName[kHostNameMaxLength + 1] = "";
     char mType[kDnssdTypeMaxSize + 1];
     DnssdServiceProtocol mProtocol;
-    Inet::IPAddressType mAddressType;
+    Inet::IPAddressType mAddressType;   // Address record type to query or publish (A or AAAA)
+    Inet::IPAddressType mTransportType; // Transport to use for the query.
     uint16_t mPort;
     chip::Inet::InterfaceId mInterface;
     TextEntry * mTextEntries;

diff --git a/src/platform/Linux/DnssdImpl.cpp b/src/platform/Linux/DnssdImpl.cpp
@@ -532,16 +532,17 @@ CHIP_ERROR MdnsAvahi::Browse(const char * type, DnssdServiceProtocol protocol, c
     BrowseContext * browseContext = chip::Platform::New<BrowseContext>();
     AvahiIfIndex avahiInterface   = static_cast<AvahiIfIndex>(interface.GetPlatformInterface());
 
-    browseContext->mInstance = this;
-    browseContext->mContext  = context;
-    browseContext->mCallback = callback;
+    browseContext->mInstance    = this;
+    browseContext->mContext     = context;
+    browseContext->mCallback    = callback;
+    browseContext->mAddressType = addressType;
     if (!interface.IsPresent())
     {
         avahiInterface = AVAHI_IF_UNSPEC;
     }
 
-    browser = avahi_service_browser_new(mClient, avahiInterface, ToAvahiProtocol(addressType), GetFullType(type, protocol).c_str(),
-                                        nullptr, static_cast<AvahiLookupFlags>(0), HandleBrowse, browseContext);
+    browser = avahi_service_browser_new(mClient, avahiInterface, AVAHI_PROTO_UNSPEC, GetFullType(type, protocol).c_str(), nullptr,
+                                        static_cast<AvahiLookupFlags>(0), HandleBrowse, browseContext);
     // Otherwise the browser will be freed in the callback
     if (browser == nullptr)
     {
@@ -613,9 +614,10 @@ void MdnsAvahi::HandleBrowse(AvahiServiceBrowser * browser, AvahiIfIndex interfa
 
             Platform::CopyString(service.mName, name);
             CopyTypeWithoutProtocol(service.mType, type);
-            service.mProtocol    = GetProtocolInType(type);
-            service.mAddressType = ToAddressType(protocol);
-            service.mInterface   = Inet::InterfaceId::Null();
+            service.mProtocol      = GetProtocolInType(type);
+            service.mAddressType   = context->mAddressType;
+            service.mTransportType = ToAddressType(protocol);
+            service.mInterface     = Inet::InterfaceId::Null();
             if (interface != AVAHI_IF_UNSPEC)
             {
                 service.mInterface = static_cast<chip::Inet::InterfaceId>(interface);
@@ -645,9 +647,9 @@ void MdnsAvahi::HandleBrowse(AvahiServiceBrowser * browser, AvahiIfIndex interfa
     }
 }
 
-CHIP_ERROR MdnsAvahi::Resolve(const char * name, const char * type, DnssdServiceProtocol protocol,
-                              chip::Inet::IPAddressType addressType, chip::Inet::InterfaceId interface,
-                              DnssdResolveCallback callback, void * context)
+CHIP_ERROR MdnsAvahi::Resolve(const char * name, const char * type, DnssdServiceProtocol protocol, Inet::IPAddressType addressType,
+                              Inet::IPAddressType transportType, Inet::InterfaceId interface, DnssdResolveCallback callback,
+                              void * context)
 {
     AvahiServiceResolver * resolver;
     AvahiIfIndex avahiInterface     = static_cast<AvahiIfIndex>(interface.GetPlatformInterface());
@@ -661,7 +663,8 @@ CHIP_ERROR MdnsAvahi::Resolve(const char * name, const char * type, DnssdService
     {
         avahiInterface = AVAHI_IF_UNSPEC;
     }
-    resolver = avahi_service_resolver_new(mClient, avahiInterface, ToAvahiProtocol(addressType), name,
+
+    resolver = avahi_service_resolver_new(mClient, avahiInterface, ToAvahiProtocol(transportType), name,
                                           GetFullType(type, protocol).c_str(), nullptr, ToAvahiProtocol(addressType),
                                           static_cast<AvahiLookupFlags>(0), HandleResolve, resolveContext);
     // Otherwise the resolver will be freed in the callback
@@ -813,18 +816,10 @@ CHIP_ERROR ChipDnssdResolve(DnssdService * browseResult, chip::Inet::InterfaceId
                             void * context)
 
 {
-    CHIP_ERROR error;
+    VerifyOrReturnError(browseResult != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
 
-    if (browseResult != nullptr)
-    {
-        error = MdnsAvahi::GetInstance().Resolve(browseResult->mName, browseResult->mType, browseResult->mProtocol,
-                                                 browseResult->mAddressType, interface, callback, context);
-    }
-    else
-    {
-        error = CHIP_ERROR_INVALID_ARGUMENT;
-    }
-    return error;
+    return MdnsAvahi::GetInstance().Resolve(browseResult->mName, browseResult->mType, browseResult->mProtocol,
+                                            browseResult->mAddressType, Inet::IPAddressType::kAny, interface, callback, context);
 }
 
 } // namespace Dnssd

diff --git a/src/platform/Linux/DnssdImpl.h b/src/platform/Linux/DnssdImpl.h
@@ -111,7 +111,8 @@ class MdnsAvahi
     CHIP_ERROR Browse(const char * type, DnssdServiceProtocol protocol, chip::Inet::IPAddressType addressType,
                       chip::Inet::InterfaceId interface, DnssdBrowseCallback callback, void * context);
     CHIP_ERROR Resolve(const char * name, const char * type, DnssdServiceProtocol protocol, chip::Inet::IPAddressType addressType,
-                       chip::Inet::InterfaceId interface, DnssdResolveCallback callback, void * context);
+                       chip::Inet::IPAddressType transportType, chip::Inet::InterfaceId interface, DnssdResolveCallback callback,
+                       void * context);
 
     Poller & GetPoller() { return mPoller; }
 
@@ -123,6 +124,7 @@ class MdnsAvahi
         MdnsAvahi * mInstance;
         DnssdBrowseCallback mCallback;
         void * mContext;
+        Inet::IPAddressType mAddressType;
         std::vector<DnssdService> mServices;
     };