7819 IPv6 Packet and MTU bug

@@ -21,11 +21,11 @@
 
 /*
  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 1990 Mentat Inc.
  * Copyright (c) 2012 Joyent, Inc. All rights reserved.
- * Copyright (c) 2014, OmniTI Computer Consulting, Inc. All rights reserved.
+ * Copyright (c) 2017 OmniTI Computer Consulting, Inc. All rights reserved.
  */
 
 #include <sys/types.h>
 #include <sys/stream.h>
 #include <sys/dlpi.h>

@@ -3856,14 +3856,13 @@
                                 pmtu = IPV6_MIN_MTU;
                 }
         }
 
         /*
-         * After receiving an ICMPv6 "packet too big" message with a
-         * MTU < 1280, and for multirouted IPv6 packets, the IP layer
-         * will insert a 8-byte fragment header in every packet. We compensate
-         * for those cases by returning a smaller path MTU to the ULP.
+         * For multirouted IPv6 packets, the IP layer will insert a 8-byte
+         * fragment header in every packet. We compensate for those cases by
+         * returning a smaller path MTU to the ULP.
          *
          * In the case of CGTP then ip_output will add a fragment header.
          * Make sure there is room for it by telling a smaller number
          * to the transport.
          *

@@ -3870,12 +3869,11 @@
          * When IXAF_IPV6_ADDR_FRAGHDR we subtract the frag hdr here
          * so the ULPs consistently see a iulp_pmtu and ip_get_pmtu()
          * which is the size of the packets it can send.
          */
         if (!(ixa->ixa_flags & IXAF_IS_IPV4)) {
-                if ((dce->dce_flags & DCEF_TOO_SMALL_PMTU) ||
-                    (ire->ire_flags & RTF_MULTIRT) ||
+                if ((ire->ire_flags & RTF_MULTIRT) ||
                     (ixa->ixa_flags & IXAF_MULTIRT_MULTICAST)) {
                         pmtu -= sizeof (ip6_frag_t);
                         ixa->ixa_flags |= IXAF_IPV6_ADD_FRAGHDR;
                 }
         }