Bug 1713689 - Add a way to set the don't-frament flag to nsUDPSocket r=necko-reviewers,valentin

Differential Revision: https://phabricator.services.mozilla.com/D116430

netwerk/base/nsIUDPSocket.idl

@@ -292,6 +292,14 @@ interface nsIUDPSocket : nsISupports
      * The size of the send buffer. Default depends on the OS.
      */
     [noscript] attribute long sendBufferSize;
+
+    /**
+     * dontFragment
+     *
+     * The don't fragment flag.
+     * The socket must be initialized before calling this function. 
+     */
+    [noscript] attribute boolean dontFragment;
 };
 
 /**

netwerk/base/nsUDPSocket.cpp

@@ -1398,6 +1398,29 @@ nsUDPSocket::SetRecvBufferSize(int size) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsUDPSocket::GetDontFragment(bool* dontFragment) {
+  // Bug 1252759 - missing support for GetSocketOption
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsUDPSocket::SetDontFragment(bool dontFragment) {
+  if (NS_WARN_IF(!mFD)) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  PRSocketOptionData opt;
+  opt.option = PR_SockOpt_DontFrag;
+  opt.value.dont_fragment = dontFragment;
+
+  nsresult rv = SetSocketOption(opt);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsUDPSocket::GetSendBufferSize(int* size) {
   // Bug 1252759 - missing support for GetSocketOption

netwerk/protocol/http/HttpConnectionUDP.cpp

@@ -110,6 +110,14 @@ nsresult HttpConnectionUDP::Init(nsHttpConnectionInfo* info,
     return rv;
   }
 
+  if (peerAddr.raw.family == AF_INET) {
+    rv = mSocket->SetDontFragment(true);
+    if (NS_FAILED(rv)) {
+      LOG(("HttpConnectionUDP::Init SetDontFragment failed %d [this=%p]",
+           static_cast<uint32_t>(rv), this));
+    }
+  }
+
   // get the resulting socket address.
   rv = mSocket->GetLocalAddr(getter_AddRefs(mSelfAddr));
   if (NS_FAILED(rv)) {