Add DTLS support to NSS, contributed by Eric Rescorla.

net/third_party/nss/ssl/ssldef.c

 /*
  * "Default" SSLSocket methods, used by sockets that do neither SSL nor socks.
  *
  * ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
@@ skipping 120 matching lines @@
             if (err == PR_WOULD_BLOCK_ERROR) {
                 ss->lastWriteBlocked = 1;
                 return sent ? sent : SECFailure;
             }
             ss->lastWriteBlocked = 0;
             MAP_ERROR(PR_CONNECT_ABORTED_ERROR, PR_CONNECT_RESET_ERROR)
             /* Loser */
             return rv;
         }
         sent += rv;
+        
+        if (IS_DTLS(ss) && (len > sent)) { 
+            /* We got a partial write so just return it */
+            return sent;
+        }
     } while (len > sent);
     ss->lastWriteBlocked = 0;
     return sent;
 }
 
 int ssl_DefRead(sslSocket *ss, unsigned char *buf, int len)
 {
     PRFileDesc *lower = ss->fd->lower;
     int rv;
 
@@ skipping 78 matching lines @@
     ** Now close the underlying socket. 
     */
     rv = fd->methods->close(fd);
 
     ssl_FreeSocket(ss);
 
     SSL_TRC(5, ("%d: SSL[%d]: closing, rv=%d errno=%d",
                 SSL_GETPID(), fd, rv, PORT_GetError()));
     return rv;
 }