Bug 1596845 - Pass TRR skip reason to child channel r=necko-reviewers,kershaw

Moves the TRRSkipReasons to nsITRRSkipReason.idl so they are available to JS.

Depends on D164345

Differential Revision: https://phabricator.services.mozilla.com/D164348

netwerk/dns/ChildDNSService.cpp

@@ -306,6 +306,12 @@ ChildDNSService::SetDetectedTrrURI(const nsACString& aURI) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+ChildDNSService::GetTRRSkipReasonName(nsITRRSkipReason::value aValue,
+                                      nsACString& aName) {
+  return mozilla::net::GetTRRSkipReasonName(aValue, aName);
+}
+
 NS_IMETHODIMP
 ChildDNSService::GetCurrentTrrURI(nsACString& aURI) {
   if (!mTRRServiceParent) {

netwerk/dns/DNSRequestChild.cpp

@@ -56,6 +56,7 @@ class ChildDNSRecord : public nsIDNSAddrRecord {
   bool mIsTRR = false;
   bool mResolvedInSocketProcess = false;
   nsIRequest::TRRMode mEffectiveTRRMode = nsIRequest::TRR_DEFAULT_MODE;
+  nsITRRSkipReason::value mTRRSkipReason = nsITRRSkipReason::TRR_UNSET;
   uint32_t mTTL = 0;
 };
 
@@ -194,6 +195,12 @@ ChildDNSRecord::GetEffectiveTRRMode(nsIRequest::TRRMode* aMode) {
   return NS_OK;
 }
 
+NS_IMETHODIMP ChildDNSRecord::GetTrrSkipReason(
+    nsITRRSkipReason::value* aTrrSkipReason) {
+  *aTrrSkipReason = mTRRSkipReason;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 ChildDNSRecord::GetTtl(uint32_t* aTtl) {
   *aTtl = mTTL;

netwerk/dns/TRR.h

@@ -17,7 +17,7 @@
 #include "nsThreadUtils.h"
 #include "nsXULAppAPI.h"
 #include "DNSPacket.h"
-#include "TRRSkippedReason.h"
+#include "nsITRRSkipReason.h"
 
 class AHostResolver;
 class nsHostRecord;

netwerk/dns/TRRSkippedReason.h

@@ -1,103 +0,0 @@
-/* vim:set ts=4 sw=2 sts=2 et cin: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef mozilla_net_TRRSkippedReason_h__
-#define mozilla_net_TRRSkippedReason_h__
-
-namespace mozilla {
-namespace net {
-
-// IMPORTANT: when adding new values, always add them to the end, otherwise
-// it will mess up telemetry.
-// When adding a reason here, make sure it is documented in
-// netwerk/docs/dns/trr-skip-reasons.md
-enum class TRRSkippedReason : uint32_t {
-  TRR_UNSET = 0,
-  TRR_OK = 1,           // Only set when we actually got a positive TRR result
-  TRR_NO_GSERVICE = 2,  // no gService
-  TRR_PARENTAL_CONTROL = 3,         // parental control is on
-  TRR_OFF_EXPLICIT = 4,             // user has set mode5
-  TRR_REQ_MODE_DISABLED = 5,        // request  has disabled flags set
-  TRR_MODE_NOT_ENABLED = 6,         // mode0
-  TRR_FAILED = 7,                   // unknown failure
-  TRR_MODE_UNHANDLED_DEFAULT = 8,   // Unhandled case in ComputeEffectiveMode
-  TRR_MODE_UNHANDLED_DISABLED = 9,  // Unhandled case in ComputeEffectiveMode
-  TRR_DISABLED_FLAG = 10,           // the DISABLE_TRR flag was set
-  TRR_TIMEOUT = 11,                 // the TRR channel timed out
-  TRR_CHANNEL_DNS_FAIL = 12,        // DoH server name failed to resolve
-  TRR_IS_OFFLINE = 13,              // The browser is offline/no interfaces up
-  TRR_NOT_CONFIRMED = 14,           // TRR confirmation is not done yet
-  TRR_DID_NOT_MAKE_QUERY = 15,  // TrrLookup exited without doing a TRR query
-  TRR_UNKNOWN_CHANNEL_FAILURE = 16,  // unknown channel failure reason
-  TRR_HOST_BLOCKED_TEMPORARY = 17,   // host blocklisted
-  TRR_SEND_FAILED = 18,              // The call to TRR::SendHTTPRequest failed
-  TRR_NET_RESET = 19,                // NS_ERROR_NET_RESET
-  TRR_NET_TIMEOUT = 20,              // NS_ERROR_NET_TIMEOUT
-  TRR_NET_REFUSED = 21,              // NS_ERROR_CONNECTION_REFUSED
-  TRR_NET_INTERRUPT = 22,            // NS_ERROR_NET_INTERRUPT
-  TRR_NET_INADEQ_SEQURITY = 23,      // NS_ERROR_NET_INADEQUATE_SECURITY
-  TRR_NO_ANSWERS = 24,               // TRR returned no answers
-  TRR_DECODE_FAILED = 25,            // DohDecode failed
-  TRR_EXCLUDED = 26,                 // ExcludedFromTRR
-  TRR_SERVER_RESPONSE_ERR = 27,      // Server responded with non-200 code
-  TRR_RCODE_FAIL = 28,          // DNS response contains a non-NOERROR rcode
-  TRR_NO_CONNECTIVITY = 29,     // Not confirmed because of no connectivity
-  TRR_NXDOMAIN = 30,            // DNS response contains NXDOMAIN rcode (0x03)
-  TRR_REQ_CANCELLED = 31,       // The request has been cancelled
-  ODOH_KEY_NOT_USABLE = 32,     // We don't have a valid ODoHConfig to use.
-  ODOH_UPDATE_KEY_FAILED = 33,  // Failed to update the ODoHConfigs.
-  ODOH_KEY_NOT_AVAILABLE = 34,  // ODoH requests timeout because of no key.
-  ODOH_ENCRYPTION_FAILED = 35,  // Failed to encrypt DNS packets.
-  ODOH_DECRYPTION_FAILED = 36,  // Failed to decrypt DNS packets.
-};
-
-inline bool IsRelevantTRRSkipReason(TRRSkippedReason aReason) {
-  // - TRR_REQ_MODE_DISABLED - these requests are intentionally skipping TRR.
-  //     These include DNS queries used to bootstrap the TRR connection,
-  //     captive portal checks, connectivity checks, etc.
-  //     Since we don't want to use TRR for these connections, we don't need
-  //     to include them with other relevant skip reasons.
-  // - TRR_DISABLED_FLAG - This reason is used when retrying failed connections,
-  //    sync DNS resolves on the main thread, or requests coming from
-  //    webextensions that choose to skip TRR
-  // - TRR_EXCLUDED - This reason is used when a certain domain is excluded
-  //    from TRR because it is explicitly set by the user, or because it
-  //    is part of the user's DNS suffix list, indicating a host that is likely
-  //    to be on the local network.
-  if (aReason == TRRSkippedReason::TRR_REQ_MODE_DISABLED ||
-      aReason == TRRSkippedReason::TRR_DISABLED_FLAG ||
-      aReason == TRRSkippedReason::TRR_EXCLUDED) {
-    return false;
-  }
-  return true;
-}
-
-inline bool IsBlockedTRRRequest(TRRSkippedReason aReason) {
-  // See TRR::MaybeBlockRequest. These are the reasons that could block sending
-  // TRR requests.
-  return (aReason == TRRSkippedReason::TRR_EXCLUDED ||
-          aReason == TRRSkippedReason::TRR_MODE_NOT_ENABLED ||
-          aReason == TRRSkippedReason::TRR_HOST_BLOCKED_TEMPORARY);
-}
-
-inline bool IsNonRecoverableTRRSkipReason(TRRSkippedReason aReason) {
-  // These are non-recoverable reasons and we'll fallback to native without
-  // retrying.
-  return (aReason == TRRSkippedReason::TRR_NXDOMAIN ||
-          aReason == TRRSkippedReason::TRR_NO_ANSWERS ||
-          aReason == TRRSkippedReason::TRR_DISABLED_FLAG ||
-          aReason == TRRSkippedReason::TRR_RCODE_FAIL);
-}
-
-inline bool IsFailedConfirmationOrNoConnectivity(TRRSkippedReason aReason) {
-  // TRR is in non-confirmed state now, so we don't try to use TRR at all.
-  return (aReason == TRRSkippedReason::TRR_NOT_CONFIRMED ||
-          aReason == TRRSkippedReason::TRR_NO_CONNECTIVITY);
-}
-
-}  // namespace net
-}  // namespace mozilla
-
-#endif  // mozilla_net_TRRSkippedReason_h__

netwerk/dns/moz.build

@@ -18,6 +18,7 @@ XPIDL_SOURCES += [
     "nsIEffectiveTLDService.idl",
     "nsIIDNService.idl",
     "nsINativeDNSResolverOverride.idl",
+    "nsITRRSkipReason.idl",
     "nsPIDNSService.idl",
 ]
 

netwerk/dns/nsDNSService2.cpp

@@ -357,6 +357,12 @@ nsDNSRecord::GetEffectiveTRRMode(nsIRequest::TRRMode* aMode) {
   return NS_OK;
 }
 
+NS_IMETHODIMP nsDNSRecord::GetTrrSkipReason(
+    nsITRRSkipReason::value* aTrrSkipReason) {
+  *aTrrSkipReason = mHostRecord->TrrSkipReason();
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDNSRecord::GetTtl(uint32_t* aTtl) { return mHostRecord->GetTtl(aTtl); }
 
@@ -1426,6 +1432,12 @@ nsDNSService::SetDetectedTrrURI(const nsACString& aURI) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDNSService::GetTRRSkipReasonName(nsITRRSkipReason::value aValue,
+                                   nsACString& aName) {
+  return mozilla::net::GetTRRSkipReasonName(aValue, aName);
+}
+
 NS_IMETHODIMP
 nsDNSService::GetCurrentTrrURI(nsACString& aURI) {
   if (mTrrService) {
@@ -1518,3 +1530,163 @@ nsDNSService::ResetExcludedSVCDomainName(const nsACString& aOwnerName) {
   mFailedSVCDomainNames.Remove(aOwnerName);
   return NS_OK;
 }
+
+namespace mozilla::net {
+nsresult GetTRRSkipReasonName(TRRSkippedReason aReason, nsACString& aName) {
+  static_assert(TRRSkippedReason::TRR_UNSET == 0);
+  static_assert(TRRSkippedReason::TRR_OK == 1);
+  static_assert(TRRSkippedReason::TRR_NO_GSERVICE == 2);
+  static_assert(TRRSkippedReason::TRR_PARENTAL_CONTROL == 3);
+  static_assert(TRRSkippedReason::TRR_OFF_EXPLICIT == 4);
+  static_assert(TRRSkippedReason::TRR_REQ_MODE_DISABLED == 5);
+  static_assert(TRRSkippedReason::TRR_MODE_NOT_ENABLED == 6);
+  static_assert(TRRSkippedReason::TRR_FAILED == 7);
+  static_assert(TRRSkippedReason::TRR_MODE_UNHANDLED_DEFAULT == 8);
+  static_assert(TRRSkippedReason::TRR_MODE_UNHANDLED_DISABLED == 9);
+  static_assert(TRRSkippedReason::TRR_DISABLED_FLAG == 10);
+  static_assert(TRRSkippedReason::TRR_TIMEOUT == 11);
+  static_assert(TRRSkippedReason::TRR_CHANNEL_DNS_FAIL == 12);
+  static_assert(TRRSkippedReason::TRR_IS_OFFLINE == 13);
+  static_assert(TRRSkippedReason::TRR_NOT_CONFIRMED == 14);
+  static_assert(TRRSkippedReason::TRR_DID_NOT_MAKE_QUERY == 15);
+  static_assert(TRRSkippedReason::TRR_UNKNOWN_CHANNEL_FAILURE == 16);
+  static_assert(TRRSkippedReason::TRR_HOST_BLOCKED_TEMPORARY == 17);
+  static_assert(TRRSkippedReason::TRR_SEND_FAILED == 18);
+  static_assert(TRRSkippedReason::TRR_NET_RESET == 19);
+  static_assert(TRRSkippedReason::TRR_NET_TIMEOUT == 20);
+  static_assert(TRRSkippedReason::TRR_NET_REFUSED == 21);
+  static_assert(TRRSkippedReason::TRR_NET_INTERRUPT == 22);
+  static_assert(TRRSkippedReason::TRR_NET_INADEQ_SEQURITY == 23);
+  static_assert(TRRSkippedReason::TRR_NO_ANSWERS == 24);
+  static_assert(TRRSkippedReason::TRR_DECODE_FAILED == 25);
+  static_assert(TRRSkippedReason::TRR_EXCLUDED == 26);
+  static_assert(TRRSkippedReason::TRR_SERVER_RESPONSE_ERR == 27);
+  static_assert(TRRSkippedReason::TRR_RCODE_FAIL == 28);
+  static_assert(TRRSkippedReason::TRR_NO_CONNECTIVITY == 29);
+  static_assert(TRRSkippedReason::TRR_NXDOMAIN == 30);
+  static_assert(TRRSkippedReason::TRR_REQ_CANCELLED == 31);
+  static_assert(TRRSkippedReason::ODOH_KEY_NOT_USABLE == 32);
+  static_assert(TRRSkippedReason::ODOH_UPDATE_KEY_FAILED == 33);
+  static_assert(TRRSkippedReason::ODOH_KEY_NOT_AVAILABLE == 34);
+  static_assert(TRRSkippedReason::ODOH_ENCRYPTION_FAILED == 35);
+  static_assert(TRRSkippedReason::ODOH_DECRYPTION_FAILED == 36);
+
+  switch (aReason) {
+    case TRRSkippedReason::TRR_UNSET:
+      aName = "TRR_UNSET"_ns;
+      break;
+    case TRRSkippedReason::TRR_OK:
+      aName = "TRR_OK"_ns;
+      break;
+    case TRRSkippedReason::TRR_NO_GSERVICE:
+      aName = "TRR_NO_GSERVICE"_ns;
+      break;
+    case TRRSkippedReason::TRR_PARENTAL_CONTROL:
+      aName = "TRR_PARENTAL_CONTROL"_ns;
+      break;
+    case TRRSkippedReason::TRR_OFF_EXPLICIT:
+      aName = "TRR_OFF_EXPLICIT"_ns;
+      break;
+    case TRRSkippedReason::TRR_REQ_MODE_DISABLED:
+      aName = "TRR_REQ_MODE_DISABLED"_ns;
+      break;
+    case TRRSkippedReason::TRR_MODE_NOT_ENABLED:
+      aName = "TRR_MODE_NOT_ENABLED"_ns;
+      break;
+    case TRRSkippedReason::TRR_FAILED:
+      aName = "TRR_FAILED"_ns;
+      break;
+    case TRRSkippedReason::TRR_MODE_UNHANDLED_DEFAULT:
+      aName = "TRR_MODE_UNHANDLED_DEFAULT"_ns;
+      break;
+    case TRRSkippedReason::TRR_MODE_UNHANDLED_DISABLED:
+      aName = "TRR_MODE_UNHANDLED_DISABLED"_ns;
+      break;
+    case TRRSkippedReason::TRR_DISABLED_FLAG:
+      aName = "TRR_DISABLED_FLAG"_ns;
+      break;
+    case TRRSkippedReason::TRR_TIMEOUT:
+      aName = "TRR_TIMEOUT"_ns;
+      break;
+    case TRRSkippedReason::TRR_CHANNEL_DNS_FAIL:
+      aName = "TRR_CHANNEL_DNS_FAIL"_ns;
+      break;
+    case TRRSkippedReason::TRR_IS_OFFLINE:
+      aName = "TRR_IS_OFFLINE"_ns;
+      break;
+    case TRRSkippedReason::TRR_NOT_CONFIRMED:
+      aName = "TRR_NOT_CONFIRMED"_ns;
+      break;
+    case TRRSkippedReason::TRR_DID_NOT_MAKE_QUERY:
+      aName = "TRR_DID_NOT_MAKE_QUERY"_ns;
+      break;
+    case TRRSkippedReason::TRR_UNKNOWN_CHANNEL_FAILURE:
+      aName = "TRR_UNKNOWN_CHANNEL_FAILURE"_ns;
+      break;
+    case TRRSkippedReason::TRR_HOST_BLOCKED_TEMPORARY:
+      aName = "TRR_HOST_BLOCKED_TEMPORARY"_ns;
+      break;
+    case TRRSkippedReason::TRR_SEND_FAILED:
+      aName = "TRR_SEND_FAILED"_ns;
+      break;
+    case TRRSkippedReason::TRR_NET_RESET:
+      aName = "TRR_NET_RESET"_ns;
+      break;
+    case TRRSkippedReason::TRR_NET_TIMEOUT:
+      aName = "TRR_NET_TIMEOUT"_ns;
+      break;
+    case TRRSkippedReason::TRR_NET_REFUSED:
+      aName = "TRR_NET_REFUSED"_ns;
+      break;
+    case TRRSkippedReason::TRR_NET_INTERRUPT:
+      aName = "TRR_NET_INTERRUPT"_ns;
+      break;
+    case TRRSkippedReason::TRR_NET_INADEQ_SEQURITY:
+      aName = "TRR_NET_INADEQ_SEQURITY"_ns;
+      break;
+    case TRRSkippedReason::TRR_NO_ANSWERS:
+      aName = "TRR_NO_ANSWERS"_ns;
+      break;
+    case TRRSkippedReason::TRR_DECODE_FAILED:
+      aName = "TRR_DECODE_FAILED"_ns;
+      break;
+    case TRRSkippedReason::TRR_EXCLUDED:
+      aName = "TRR_EXCLUDED"_ns;
+      break;
+    case TRRSkippedReason::TRR_SERVER_RESPONSE_ERR:
+      aName = "TRR_SERVER_RESPONSE_ERR"_ns;
+      break;
+    case TRRSkippedReason::TRR_RCODE_FAIL:
+      aName = "TRR_RCODE_FAIL"_ns;
+      break;
+    case TRRSkippedReason::TRR_NO_CONNECTIVITY:
+      aName = "TRR_NO_CONNECTIVITY"_ns;
+      break;
+    case TRRSkippedReason::TRR_NXDOMAIN:
+      aName = "TRR_NXDOMAIN"_ns;
+      break;
+    case TRRSkippedReason::TRR_REQ_CANCELLED:
+      aName = "TRR_REQ_CANCELLED"_ns;
+      break;
+    case TRRSkippedReason::ODOH_KEY_NOT_USABLE:
+      aName = "ODOH_KEY_NOT_USABLE"_ns;
+      break;
+    case TRRSkippedReason::ODOH_UPDATE_KEY_FAILED:
+      aName = "ODOH_UPDATE_KEY_FAILED"_ns;
+      break;
+    case TRRSkippedReason::ODOH_KEY_NOT_AVAILABLE:
+      aName = "ODOH_KEY_NOT_AVAILABLE"_ns;
+      break;
+    case TRRSkippedReason::ODOH_ENCRYPTION_FAILED:
+      aName = "ODOH_ENCRYPTION_FAILED"_ns;
+      break;
+    case TRRSkippedReason::ODOH_DECRYPTION_FAILED:
+      aName = "ODOH_DECRYPTION_FAILED"_ns;
+      break;
+    default:
+      MOZ_ASSERT(false, "Unknown value");
+  }
+
+  return NS_OK;
+}
+}  // namespace mozilla::net

netwerk/dns/nsHostRecord.cpp

@@ -7,7 +7,6 @@
 #include "TRRQuery.h"
 // Put DNSLogging.h at the end to avoid LOG being overwritten by other headers.
 #include "DNSLogging.h"
-#include "TRRSkippedReason.h"
 #include "mozilla/StaticPrefs_network.h"
 #include "mozilla/Telemetry.h"
 #include "TRRService.h"

netwerk/dns/nsHostRecord.h

@@ -13,7 +13,7 @@
 #include "nsIDNSService.h"
 #include "nsIDNSByTypeRecord.h"
 #include "PLDHashTable.h"
-#include "TRRSkippedReason.h"
+#include "nsITRRSkipReason.h"
 
 class nsHostRecord;
 class nsHostResolver;
@@ -269,6 +269,7 @@ class AddrHostRecord final : public nsHostRecord {
   size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const override;
 
   nsIRequest::TRRMode EffectiveTRRMode() const { return mEffectiveTRRMode; }
+  nsITRRSkipReason::value TrrSkipReason() const { return mTRRSkippedReason; }
 
   nsresult GetTtl(uint32_t* aResult);
 

netwerk/dns/nsIDNSRecord.idl

@@ -4,6 +4,7 @@
 
 #include "nsISupports.idl"
 #include "nsIRequest.idl"
+#include "nsITRRSkipReason.idl"
 
 %{ C++
 namespace mozilla {
@@ -140,6 +141,12 @@ interface nsIDNSAddrRecord : nsIDNSRecord
      */
     readonly attribute nsIRequest_TRRMode effectiveTRRMode;
 
+    /**
+     * If the DNS request didn't use TRR, this value
+     * contains the reason why that was skipped.
+     */
+    readonly attribute nsITRRSkipReason_value trrSkipReason;
+
     /**
      * Returns the ttl of this record.
      */

netwerk/dns/nsIDNSService.idl

@@ -4,6 +4,7 @@
 
 #include "nsISupports.idl"
 #include "nsIRequest.idl"
+#include "nsITRRSkipReason.idl"
 
 %{ C++
 #include "mozilla/BasePrincipal.h"
@@ -207,6 +208,8 @@ interface nsIDNSService : nsISupports
      */
     void setDetectedTrrURI(in AUTF8String aURI);
 
+    ACString getTRRSkipReasonName(in nsITRRSkipReason_value value);
+
     /**
      * Notifies the DNS service that we failed to connect to this alternative
      * endpoint.

netwerk/dns/nsITRRSkipReason.idl

@@ -0,0 +1,109 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(e61b5d39-f6d6-4ed3-aead-1213b24c6f27)]
+interface nsITRRSkipReason: nsISupports
+{
+  // IMPORTANT: when adding new values, always add them to the end, otherwise
+  // it will mess up telemetry.
+  // When adding a reason here, make sure it is documented in
+  // netwerk/docs/dns/trr-skip-reasons.md
+  cenum value: 8 {
+    TRR_UNSET = 0,
+    TRR_OK = 1,           // Only set when we actually got a positive TRR result
+    TRR_NO_GSERVICE = 2,  // no gService
+    TRR_PARENTAL_CONTROL = 3,         // parental control is on
+    TRR_OFF_EXPLICIT = 4,             // user has set mode5
+    TRR_REQ_MODE_DISABLED = 5,        // request  has disabled flags set
+    TRR_MODE_NOT_ENABLED = 6,         // mode0
+    TRR_FAILED = 7,                   // unknown failure
+    TRR_MODE_UNHANDLED_DEFAULT = 8,   // Unhandled case in ComputeEffectiveMode
+    TRR_MODE_UNHANDLED_DISABLED = 9,  // Unhandled case in ComputeEffectiveMode
+    TRR_DISABLED_FLAG = 10,           // the DISABLE_TRR flag was set
+    TRR_TIMEOUT = 11,                 // the TRR channel timed out
+    TRR_CHANNEL_DNS_FAIL = 12,        // DoH server name failed to resolve
+    TRR_IS_OFFLINE = 13,              // The browser is offline/no interfaces up
+    TRR_NOT_CONFIRMED = 14,           // TRR confirmation is not done yet
+    TRR_DID_NOT_MAKE_QUERY = 15,  // TrrLookup exited without doing a TRR query
+    TRR_UNKNOWN_CHANNEL_FAILURE = 16,  // unknown channel failure reason
+    TRR_HOST_BLOCKED_TEMPORARY = 17,   // host blocklisted
+    TRR_SEND_FAILED = 18,              // The call to TRR::SendHTTPRequest failed
+    TRR_NET_RESET = 19,                // NS_ERROR_NET_RESET
+    TRR_NET_TIMEOUT = 20,              // NS_ERROR_NET_TIMEOUT
+    TRR_NET_REFUSED = 21,              // NS_ERROR_CONNECTION_REFUSED
+    TRR_NET_INTERRUPT = 22,            // NS_ERROR_NET_INTERRUPT
+    TRR_NET_INADEQ_SEQURITY = 23,      // NS_ERROR_NET_INADEQUATE_SECURITY
+    TRR_NO_ANSWERS = 24,               // TRR returned no answers
+    TRR_DECODE_FAILED = 25,            // DohDecode failed
+    TRR_EXCLUDED = 26,                 // ExcludedFromTRR
+    TRR_SERVER_RESPONSE_ERR = 27,      // Server responded with non-200 code
+    TRR_RCODE_FAIL = 28,          // DNS response contains a non-NOERROR rcode
+    TRR_NO_CONNECTIVITY = 29,     // Not confirmed because of no connectivity
+    TRR_NXDOMAIN = 30,            // DNS response contains NXDOMAIN rcode (0x03)
+    TRR_REQ_CANCELLED = 31,       // The request has been cancelled
+    ODOH_KEY_NOT_USABLE = 32,     // We don't have a valid ODoHConfig to use.
+    ODOH_UPDATE_KEY_FAILED = 33,  // Failed to update the ODoHConfigs.
+    ODOH_KEY_NOT_AVAILABLE = 34,  // ODoH requests timeout because of no key.
+    ODOH_ENCRYPTION_FAILED = 35,  // Failed to encrypt DNS packets.
+    ODOH_DECRYPTION_FAILED = 36,  // Failed to decrypt DNS packets.
+  };
+};
+
+%{ C++
+namespace mozilla {
+namespace net {
+
+using TRRSkippedReason = nsITRRSkipReason::value;
+
+inline bool IsRelevantTRRSkipReason(TRRSkippedReason aReason) {
+  // - TRR_REQ_MODE_DISABLED - these requests are intentionally skipping TRR.
+  //     These include DNS queries used to bootstrap the TRR connection,
+  //     captive portal checks, connectivity checks, etc.
+  //     Since we don't want to use TRR for these connections, we don't need
+  //     to include them with other relevant skip reasons.
+  // - TRR_DISABLED_FLAG - This reason is used when retrying failed connections,
+  //    sync DNS resolves on the main thread, or requests coming from
+  //    webextensions that choose to skip TRR
+  // - TRR_EXCLUDED - This reason is used when a certain domain is excluded
+  //    from TRR because it is explicitly set by the user, or because it
+  //    is part of the user's DNS suffix list, indicating a host that is likely
+  //    to be on the local network.
+  if (aReason == TRRSkippedReason::TRR_REQ_MODE_DISABLED ||
+      aReason == TRRSkippedReason::TRR_DISABLED_FLAG ||
+      aReason == TRRSkippedReason::TRR_EXCLUDED) {
+    return false;
+  }
+  return true;
+}
+
+inline bool IsBlockedTRRRequest(TRRSkippedReason aReason) {
+  // See TRR::MaybeBlockRequest. These are the reasons that could block sending
+  // TRR requests.
+  return (aReason == TRRSkippedReason::TRR_EXCLUDED ||
+          aReason == TRRSkippedReason::TRR_MODE_NOT_ENABLED ||
+          aReason == TRRSkippedReason::TRR_HOST_BLOCKED_TEMPORARY);
+}
+
+inline bool IsNonRecoverableTRRSkipReason(TRRSkippedReason aReason) {
+  // These are non-recoverable reasons and we'll fallback to native without
+  // retrying.
+  return (aReason == TRRSkippedReason::TRR_NXDOMAIN ||
+          aReason == TRRSkippedReason::TRR_NO_ANSWERS ||
+          aReason == TRRSkippedReason::TRR_DISABLED_FLAG ||
+          aReason == TRRSkippedReason::TRR_RCODE_FAIL);
+}
+
+inline bool IsFailedConfirmationOrNoConnectivity(TRRSkippedReason aReason) {
+  // TRR is in non-confirmed state now, so we don't try to use TRR at all.
+  return (aReason == TRRSkippedReason::TRR_NOT_CONFIRMED ||
+          aReason == TRRSkippedReason::TRR_NO_CONNECTIVITY);
+}
+
+extern nsresult GetTRRSkipReasonName(TRRSkippedReason aReason, nsACString& aName);
+
+} // net
+} // mozilla
+%}

netwerk/docs/dns/trr-skip-reasons.md

@@ -1,6 +1,6 @@
 # TRRSkippedReasons
 
-These values are defined in [TRRSkippedReason.h](https://searchfox.org/mozilla-central/source/netwerk/dns/TRRSkippedReason.h) and are recorded on _nsHostRecord_ for each resolution.
+These values are defined in [TRRSkippedReason.h](https://searchfox.org/mozilla-central/source/netwerk/dns/nsITRRSkipReason.idl) and are recorded on _nsHostRecord_ for each resolution.
 We normally use them for telemetry or to determine the cause of a TRR failure.
 
 

netwerk/ipc/NeckoMessageUtils.h

@@ -17,6 +17,7 @@
 #include "prio.h"
 #include "mozilla/net/DNS.h"
 #include "ipc/IPCMessageUtilsSpecializations.h"
+#include "nsITRRSkipReason.h"
 
 namespace IPC {
 
@@ -142,6 +143,23 @@ struct ParamTraits<nsIRequest::TRRMode> {
   }
 };
 
+template <>
+struct ParamTraits<nsITRRSkipReason::value> {
+  static void Write(MessageWriter* aWriter,
+                    const nsITRRSkipReason::value& aParam) {
+    WriteParam(aWriter, (uint8_t)aParam);
+  }
+  static bool Read(MessageReader* aReader, nsITRRSkipReason::value* aResult) {
+    uint8_t reason;
+    if (!ReadParam(aReader, &reason)) {
+      return false;
+    }
+    // TODO: sanity check
+    *aResult = static_cast<nsITRRSkipReason::value>(reason);
+    return true;
+  }
+};
+
 }  // namespace IPC
 
 #endif  // mozilla_net_NeckoMessageUtils_h

netwerk/protocol/http/HttpBaseChannel.cpp

@@ -3606,6 +3606,12 @@ HttpBaseChannel::GetEffectiveTRRMode(nsIRequest::TRRMode* aEffectiveTRRMode) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+HttpBaseChannel::GetTrrSkipReason(nsITRRSkipReason::value* aTrrSkipReason) {
+  *aTrrSkipReason = mTRRSkipReason;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 HttpBaseChannel::GetIsLoadedBySocketProcess(bool* aResult) {
   NS_ENSURE_ARG_POINTER(aResult);

netwerk/protocol/http/HttpBaseChannel.h

@@ -283,6 +283,7 @@ class HttpBaseChannel : public nsHashPropertyBag,
   NS_IMETHOD GetIsResolvedByTRR(bool* aResolvedByTRR) override;
   NS_IMETHOD GetEffectiveTRRMode(
       nsIRequest::TRRMode* aEffectiveTRRMode) override;
+  NS_IMETHOD GetTrrSkipReason(nsITRRSkipReason::value* aTrrSkipReason) override;
   NS_IMETHOD GetIsLoadedBySocketProcess(bool* aResult) override;
   NS_IMETHOD GetIsOCSP(bool* value) override;
   NS_IMETHOD SetIsOCSP(bool value) override;
@@ -794,6 +795,7 @@ class HttpBaseChannel : public nsHashPropertyBag,
   // Is initially set to TRR_DEFAULT_MODE, but should be updated to the actual
   // mode used by the request
   nsIRequest::TRRMode mEffectiveTRRMode = nsIRequest::TRR_DEFAULT_MODE;
+  TRRSkippedReason mTRRSkipReason = TRRSkippedReason::TRR_UNSET;
 
  public:
   void SetEarlyHints(

netwerk/protocol/http/HttpChannelChild.cpp

@@ -433,6 +433,7 @@ void HttpChannelChild::OnStartRequest(
   mAltDataLength = aArgs.altDataLength();
   StoreResolvedByTRR(aArgs.isResolvedByTRR());
   mEffectiveTRRMode = aArgs.effectiveTRRMode();
+  mTRRSkipReason = aArgs.trrSkipReason();
 
   SetApplyConversion(aArgs.applyConversion());
 

netwerk/protocol/http/HttpChannelParams.ipdlh

@@ -20,6 +20,7 @@ using nsILoadInfo::CrossOriginOpenerPolicy from "nsILoadInfo.h";
 [RefCounted] using class nsIReferrerInfo from "nsIReferrerInfo.h";
 [RefCounted] using class nsITransportSecurityInfo from "nsITransportSecurityInfo.h";
 using nsIRequest::TRRMode from "nsIRequest.h";
+using TRRSkippedReason from "nsITRRSkipReason.h";
 
 namespace mozilla {
 namespace net {
@@ -57,6 +58,7 @@ struct HttpChannelOnStartRequestArgs
   bool hasHTTPSRR;
   bool isProxyUsed;
   TRRMode effectiveTRRMode;
+  TRRSkippedReason trrSkipReason;
 };
 
 struct HttpChannelAltDataStream

netwerk/protocol/http/HttpChannelParent.cpp

@@ -1263,6 +1263,10 @@ HttpChannelParent::OnStartRequest(nsIRequest* aRequest) {
   mChannel->GetEffectiveTRRMode(&effectiveMode);
   args.effectiveTRRMode() = effectiveMode;
 
+  TRRSkippedReason reason = TRRSkippedReason::TRR_UNSET;
+  mChannel->GetTrrSkipReason(&reason);
+  args.trrSkipReason() = reason;
+
   if (mIPCClosed ||
       !mBgParent->OnStartRequest(
           *responseHead, useResponseHead,

netwerk/protocol/http/nsHttpChannel.cpp

@@ -8531,6 +8531,7 @@ nsHttpChannel::OnLookupComplete(nsICancelable* request, nsIDNSRecord* rec,
 
   if (nsCOMPtr<nsIDNSAddrRecord> r = do_QueryInterface(rec)) {
     r->GetEffectiveTRRMode(&mEffectiveTRRMode);
+    r->GetTrrSkipReason(&mTRRSkipReason);
   }
 
   LOG(

netwerk/protocol/http/nsIHttpChannelInternal.idl

@@ -6,6 +6,7 @@
 #include "nsISupports.idl"
 #include "nsILoadInfo.idl"
 #include "nsIRequest.idl"
+#include "nsITRRSkipReason.idl"
 
 %{C++
 #include "nsStringFwd.h"
@@ -293,6 +294,12 @@ interface nsIHttpChannelInternal : nsISupports
      */
     [must_use] readonly attribute nsIRequest_TRRMode effectiveTRRMode;
 
+    /**
+     * If the DNS request triggered by this channel didn't use TRR, this value
+     * contains the reason why that was skipped.
+     */
+    [must_use] readonly attribute nsITRRSkipReason_value trrSkipReason;
+
     /**
      * True if channel is loaded by socket process.
      */