Add DTLS support to NSS, contributed by Eric Rescorla.

net/third_party/nss/ssl/ssl.h

Index: net/third_party/nss/ssl/ssl.h
===================================================================
--- net/third_party/nss/ssl/ssl.h	(revision 127709)
+++ net/third_party/nss/ssl/ssl.h	(working copy)
@@ -80,6 +80,12 @@
 SSL_IMPORT PRFileDesc *SSL_ImportFD(PRFileDesc *model, PRFileDesc *fd);
 
 /*
+** Imports fd into DTLS, returning a new socket.  Copies DTLS configuration
+** from model.
+*/
+SSL_IMPORT PRFileDesc *DTLS_ImportFD(PRFileDesc *model, PRFileDesc *fd);
+
+/*
 ** Enable/disable an ssl mode
 **
 ** 	SSL_SECURITY:
@@ -942,6 +948,14 @@
                                                  PRBool *last_handshake_resumed);
 
 /*
+** How long should we wait before retransmitting the next flight of
+** the DTLS handshake? Returns SECFailure if not DTLS or not in a
+** handshake.
+*/
+SSL_IMPORT SECStatus DTLS_GetTimeout(PRFileDesc *socket,
+                                     PRIntervalTime *timeout);
+
+/*
  * Return a boolean that indicates whether the underlying library
  * will perform as the caller expects.
  *