Warning about DCE lifetimes
coyright fix
gdamore's feedback
7185 IP DCEs leak from halted non-global zones

*** 20,29 ****
--- 20,30 ----
   */
  
  /*
   * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2012, Joyent, Inc. All rights reserved.
+  * Copyright 2017, OmniTI Computer Consulting, Inc. All rights reserved.
   */
  
  #include <sys/types.h>
  #include <sys/stream.h>
  #include <sys/strsun.h>
*** 88,97 ****
--- 89,102 ----
   *                      return failure;
   *      }
   *
   * Note that for IPv6 link-local addresses we record the ifindex since the
   * link-locals are not globally unique.
+  *
+  * DCEs can remain for an arbitrarily long time, until memory pressure or
+  * too-deep hash buckets (see dce_lookup_and_add*()) enable the reclaim thread
+  * to actually remove DCEs from the cache.
   */
  
  /*
   * Hash bucket structure for DCEs
   */
*** 324,339 ****
--- 329,369 ----
                  rw_init(&ipst->ips_dce_hash_v6[i].dcb_lock, NULL, RW_DEFAULT,
                      NULL);
          }
  }
  
+ /*
+  * Given a DCE hash bucket, unlink DCE entries from it. Some callers need
+  * ifindex-specific matching, others don't. Don't overload ifindex to indicate
+  * specificity, just indicate so explicitly.
+  */
+ static void
+ dce_bucket_clean(dcb_t *dcb, boolean_t specific_ifindex, uint_t ifindex)
+ {
+         dce_t   *dce, *nextdce;
+ 
+         rw_enter(&dcb->dcb_lock, RW_WRITER);
+ 
+         for (dce = dcb->dcb_dce; dce != NULL; dce = nextdce) {
+                 nextdce = dce->dce_next;
+                 if ((!specific_ifindex) || dce->dce_ifindex == ifindex) {
+                         dce_delete_locked(dcb, dce);
+                         dce_refrele(dce);
+                 }
+         }
+ 
+         rw_exit(&dcb->dcb_lock);
+ }
+ 
  void
  dce_stack_destroy(ip_stack_t *ipst)
  {
          int i;
          for (i = 0; i < ipst->ips_dce_hashsize; i++) {
+                 dce_bucket_clean(&ipst->ips_dce_hash_v4[i], B_FALSE, 0);
                  rw_destroy(&ipst->ips_dce_hash_v4[i].dcb_lock);
+                 dce_bucket_clean(&ipst->ips_dce_hash_v6[i], B_FALSE, 0);
                  rw_destroy(&ipst->ips_dce_hash_v6[i].dcb_lock);
          }
          kmem_free(ipst->ips_dce_hash_v4,
              ipst->ips_dce_hashsize * sizeof (dcb_t));
          ipst->ips_dce_hash_v4 = NULL;
*** 953,974 ****
   */
  void
  dce_cleanup(uint_t ifindex, ip_stack_t *ipst)
  {
          uint_t  i;
-         dcb_t   *dcb;
-         dce_t   *dce, *nextdce;
  
!         for (i = 0; i < ipst->ips_dce_hashsize; i++) {
!                 dcb = &ipst->ips_dce_hash_v6[i];
!                 rw_enter(&dcb->dcb_lock, RW_WRITER);
! 
!                 for (dce = dcb->dcb_dce; dce != NULL; dce = nextdce) {
!                         nextdce = dce->dce_next;
!                         if (dce->dce_ifindex == ifindex) {
!                                 dce_delete_locked(dcb, dce);
!                                 dce_refrele(dce);
!                         }
!                 }
!                 rw_exit(&dcb->dcb_lock);
!         }
  }
--- 983,991 ----
   */
  void
  dce_cleanup(uint_t ifindex, ip_stack_t *ipst)
  {
          uint_t  i;
  
!         for (i = 0; i < ipst->ips_dce_hashsize; i++)
!                 dce_bucket_clean(&ipst->ips_dce_hash_v6[i], B_TRUE, ifindex);
  }