6953249 memory leak in dlmgmtd

6949971 dlmgmtd keeps consuming memory
6826131 dlmgmtd's parse_linkprops() suffers from memory mismanagement
6846855 vlan rcm support could use a code review

21 files changed, 546 insertions, 341 deletions

diff --git a/usr/src/cmd/cmd-inet/usr.lib/bridged/events.c b/usr/src/cmd/cmd-inet/usr.lib/bridged/events.c
index fe64506d1e..dee468df9a 100644
--- a/usr/src/cmd/cmd-inet/usr.lib/bridged/events.c
+++ b/usr/src/cmd/cmd-inet/usr.lib/bridged/events.c
@@ -20,8 +20,7 @@
  */
 
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 /*
@@ -323,18 +322,10 @@ static int
 update_link(dladm_handle_t handle, datalink_id_t linkid, void *arg)
 {
 	dladm_status_t status;
-	dladm_conf_t conf;
 	char bridge[MAXLINKNAMELEN], linkname[MAXLINKNAMELEN];
 	char pointless[DLADM_STRSIZE];
 	datalink_class_t class;
 
-	status = dladm_read_conf(handle, linkid, &conf);
-	if (status != DLADM_STATUS_OK) {
-		syslog(LOG_DEBUG, "can't get status on link ID %u: %s", linkid,
-		    dladm_status2str(status, pointless));
-		return (DLADM_WALK_CONTINUE);
-	}
-
 	status = dladm_bridge_getlink(handle, linkid, bridge, sizeof (bridge));
 	if (status == DLADM_STATUS_OK && strcmp(bridge, instance_name) == 0) {
 		status = dladm_datalink_id2info(handle, linkid, NULL, &class,
@@ -354,7 +345,6 @@ update_link(dladm_handle_t handle, datalink_id_t linkid, void *arg)
 			syslog(LOG_DEBUG, "link ID %u is on bridge %s, not %s",
 			    linkid, bridge, instance_name);
 	}
-	dladm_destroy_conf(handle, conf);
 	return (DLADM_WALK_CONTINUE);
 }
 
diff --git a/usr/src/cmd/dladm/dladm.c b/usr/src/cmd/dladm/dladm.c
index c07fc2cb49..c6c19724a4 100644
--- a/usr/src/cmd/dladm/dladm.c
+++ b/usr/src/cmd/dladm/dladm.c
@@ -9142,7 +9142,7 @@ print_part(show_part_state_t *state, datalink_id_t linkid)
 	 * we want up-part to always succeed even if the port is currently down
 	 * or P_Key is not yet available in the subnet.
 	 */
-	if ((status = dladm_read_conf(handle, linkid, &conf)) ==
+	if ((status = dladm_getsnap_conf(handle, linkid, &conf)) ==
 	    DLADM_STATUS_OK) {
 		(void) dladm_get_conf_field(handle, conf, FFORCE,
 		    &force_in_conf, sizeof (boolean_t));
diff --git a/usr/src/cmd/dlmgmtd/dlmgmt_db.c b/usr/src/cmd/dlmgmtd/dlmgmt_db.c
index 7a97985de3..7cb9e2ce78 100644
--- a/usr/src/cmd/dlmgmtd/dlmgmt_db.c
+++ b/usr/src/cmd/dlmgmtd/dlmgmt_db.c
@@ -20,8 +20,7 @@
  */
 
 /*
- * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #include <assert.h>
@@ -711,7 +710,6 @@ parse_linkprops(char *buf, dlmgmt_link_t *linkp)
 	boolean_t		found_type = B_FALSE;
 	dladm_datatype_t	type = DLADM_TYPE_STR;
 	int			i, len;
-	int			err = 0;
 	char			*curr;
 	char			attr_name[MAXLINKATTRLEN];
 	size_t			attr_buf_len = 0;
@@ -720,7 +718,7 @@ parse_linkprops(char *buf, dlmgmt_link_t *linkp)
 	curr = buf;
 	len = strlen(buf);
 	attr_name[0] = '\0';
-	for (i = 0; i < len && err == 0; i++) {
+	for (i = 0; i < len; i++) {
 		char		c = buf[i];
 		boolean_t	match = (c == '=' ||
 		    (c == ',' && !found_type) || c == ';');
@@ -751,26 +749,36 @@ parse_linkprops(char *buf, dlmgmt_link_t *linkp)
 				goto parse_fail;
 
 			if (strcmp(attr_name, "linkid") == 0) {
-				(void) read_int64(curr, &attr_buf);
+				if (read_int64(curr, &attr_buf) == 0)
+					goto parse_fail;
 				linkp->ll_linkid =
 				    (datalink_class_t)*(int64_t *)attr_buf;
 			} else if (strcmp(attr_name, "name") == 0) {
-				(void) read_str(curr, &attr_buf);
+				if (read_str(curr, &attr_buf) == 0)
+					goto parse_fail;
 				(void) snprintf(linkp->ll_link,
 				    MAXLINKNAMELEN, "%s", attr_buf);
 			} else if (strcmp(attr_name, "class") == 0) {
-				(void) read_int64(curr, &attr_buf);
+				if (read_int64(curr, &attr_buf) == 0)
+					goto parse_fail;
 				linkp->ll_class =
 				    (datalink_class_t)*(int64_t *)attr_buf;
 			} else if (strcmp(attr_name, "media") == 0) {
-				(void) read_int64(curr, &attr_buf);
+				if (read_int64(curr, &attr_buf) == 0)
+					goto parse_fail;
 				linkp->ll_media =
 				    (uint32_t)*(int64_t *)attr_buf;
 			} else {
 				attr_buf_len = translators[type].read_func(curr,
 				    &attr_buf);
-				err = linkattr_set(&(linkp->ll_head), attr_name,
-				    attr_buf, attr_buf_len, type);
+				if (attr_buf_len == 0)
+					goto parse_fail;
+
+				if (linkattr_set(&(linkp->ll_head), attr_name,
+				    attr_buf, attr_buf_len, type) != 0) {
+					free(attr_buf);
+					goto parse_fail;
+				}
 			}
 
 			free(attr_buf);
@@ -806,9 +814,13 @@ parse_linkprops(char *buf, dlmgmt_link_t *linkp)
 		curr = buf + i + 1;
 	}
 
-	return (err);
+	return (0);
 
 parse_fail:
+	/*
+	 * Free linkp->ll_head (link attribute list)
+	 */
+	linkattr_destroy(linkp);
 	return (-1);
 }
 
@@ -986,6 +998,12 @@ process_db_write(dlmgmt_db_req_t *req, FILE *fp, FILE *nfp)
 
 	while (err == 0 && fgets(buf, sizeof (buf), fp) != NULL &&
 	    process_link_line(buf, &link_in_file)) {
+		/*
+		 * Only the link name is needed. Free the memory allocated for
+		 * the link attributes list of link_in_file.
+		 */
+		linkattr_destroy(&link_in_file);
+
 		if (link_in_file.ll_link[0] == '\0' || done) {
 			/*
 			 * this is a comment line or we are done updating the
@@ -1089,12 +1107,16 @@ process_db_read(dlmgmt_db_req_t *req, FILE *fp)
 		/*
 		 * Skip the comment line.
 		 */
-		if (link_in_file.ll_link[0] == '\0')
+		if (link_in_file.ll_link[0] == '\0') {
+			linkattr_destroy(&link_in_file);
 			continue;
+		}
 
 		if ((req->ls_flags & DLMGMT_ACTIVE) &&
-		    link_in_file.ll_linkid == DATALINK_INVALID_LINKID)
+		    link_in_file.ll_linkid == DATALINK_INVALID_LINKID) {
+			linkattr_destroy(&link_in_file);
 			continue;
+		}
 
 		link_in_file.ll_zoneid = req->ls_zoneid;
 		link_in_db = avl_find(&dlmgmt_name_avl, &link_in_file,
@@ -1110,6 +1132,7 @@ process_db_read(dlmgmt_db_req_t *req, FILE *fp)
 				dlmgmt_log(LOG_WARNING, "Duplicate links "
 				    "in the repository: %s",
 				    link_in_file.ll_link);
+				linkattr_destroy(&link_in_file);
 			} else {
 				if (req->ls_flags & DLMGMT_PERSIST) {
 					/*
@@ -1119,6 +1142,8 @@ process_db_read(dlmgmt_db_req_t *req, FILE *fp)
 					assert(link_in_db->ll_head == NULL);
 					link_in_db->ll_head =
 					    link_in_file.ll_head;
+				} else {
+					linkattr_destroy(&link_in_file);
 				}
 				link_in_db->ll_flags |= req->ls_flags;
 			}
@@ -1132,6 +1157,7 @@ process_db_read(dlmgmt_db_req_t *req, FILE *fp)
 				dlmgmt_log(LOG_WARNING, "Unable to allocate "
 				    "memory to create new link %s",
 				    link_in_file.ll_link);
+				linkattr_destroy(&link_in_file);
 				continue;
 			}
 			bcopy(&link_in_file, newlink, sizeof (*newlink));
diff --git a/usr/src/cmd/dlmgmtd/dlmgmt_door.c b/usr/src/cmd/dlmgmtd/dlmgmt_door.c
index 904dcbbd98..11e4329669 100644
--- a/usr/src/cmd/dlmgmtd/dlmgmt_door.c
+++ b/usr/src/cmd/dlmgmtd/dlmgmt_door.c
@@ -20,8 +20,7 @@
  */
 
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 /*
@@ -61,7 +60,8 @@
 #include <librcm.h>
 #include "dlmgmt_impl.h"
 
-typedef void dlmgmt_door_handler_t(void *, void *, zoneid_t, ucred_t *);
+typedef void dlmgmt_door_handler_t(void *, void *, size_t *, zoneid_t,
+    ucred_t *);
 
 typedef struct dlmgmt_door_info_s {
 	uint_t			di_cmd;
@@ -136,8 +136,10 @@ done:
 	nvlist_free(nvl);
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_upcall_create(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_upcall_create(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_upcall_arg_create_t *create = argp;
 	dlmgmt_create_retval_t	*retvalp = retp;
@@ -274,8 +276,10 @@ noupdate:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_upcall_update(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_upcall_update(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_upcall_arg_update_t	*update = argp;
 	dlmgmt_update_retval_t		*retvalp = retp;
@@ -348,8 +352,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_upcall_destroy(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_upcall_destroy(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_upcall_arg_destroy_t	*destroy = argp;
 	dlmgmt_destroy_retval_t		*retvalp = retp;
@@ -396,7 +402,8 @@ done:
 
 /* ARGSUSED */
 static void
-dlmgmt_getname(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_getname(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_getname_t	*getname = argp;
 	dlmgmt_getname_retval_t	*retvalp = retp;
@@ -424,7 +431,8 @@ dlmgmt_getname(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 
 /* ARGSUSED */
 static void
-dlmgmt_getlinkid(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_getlinkid(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_getlinkid_t	*getlinkid = argp;
 	dlmgmt_getlinkid_retval_t *retvalp = retp;
@@ -456,7 +464,8 @@ done:
 
 /* ARGSUSED */
 static void
-dlmgmt_getnext(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_getnext(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_getnext_t	*getnext = argp;
 	dlmgmt_getnext_retval_t	*retvalp = retp;
@@ -498,7 +507,8 @@ dlmgmt_getnext(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 
 /* ARGSUSED */
 static void
-dlmgmt_upcall_getattr(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_upcall_getattr(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_upcall_arg_getattr_t	*getattr = argp;
 	dlmgmt_getattr_retval_t		*retvalp = retp;
@@ -517,8 +527,10 @@ dlmgmt_upcall_getattr(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 	dlmgmt_table_unlock();
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_createid(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_createid(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_createid_t	*createid = argp;
 	dlmgmt_createid_retval_t *retvalp = retp;
@@ -566,8 +578,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_destroyid(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_destroyid(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_destroyid_t	*destroyid = argp;
 	dlmgmt_destroyid_retval_t *retvalp = retp;
@@ -605,8 +619,10 @@ done:
  * (ld_linkid) to a non-existent link2 (ld_link): rename link1's name to
  * the given link name.
  */
+/* ARGSUSED */
 static void
-dlmgmt_remapid(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_remapid(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_remapid_t	*remapid = argp;
 	dlmgmt_remapid_retval_t	*retvalp = retp;
@@ -671,8 +687,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_upid(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_upid(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_upid_t	*upid = argp;
 	dlmgmt_upid_retval_t	*retvalp = retp;
@@ -705,8 +723,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_createconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_createconf(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_createconf_t *createconf = argp;
 	dlmgmt_createconf_retval_t *retvalp = retp;
@@ -726,15 +746,17 @@ dlmgmt_createconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 	if (err == 0) {
 		avl_add(&dlmgmt_dlconf_avl, dlconfp);
 		dlmgmt_advance_dlconfid(dlconfp);
-		retvalp->lr_conf = (dladm_conf_t)dlconfp->ld_id;
+		retvalp->lr_confid = dlconfp->ld_id;
 	}
 done:
 	dlmgmt_dlconf_table_unlock();
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_setattr(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_setattr(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_setattr_t	*setattr = argp;
 	dlmgmt_setattr_retval_t	*retvalp = retp;
@@ -746,7 +768,7 @@ dlmgmt_setattr(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 	 */
 	dlmgmt_dlconf_table_lock(B_TRUE);
 
-	dlconf.ld_id = (int)setattr->ld_conf;
+	dlconf.ld_id = setattr->ld_confid;
 	dlconfp = avl_find(&dlmgmt_dlconf_avl, &dlconf, NULL);
 	if (dlconfp == NULL || zoneid != dlconfp->ld_zoneid) {
 		err = ENOENT;
@@ -764,8 +786,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_unsetconfattr(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_unsetconfattr(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_unsetattr_t	*unsetattr = argp;
 	dlmgmt_unsetattr_retval_t *retvalp = retp;
@@ -777,7 +801,7 @@ dlmgmt_unsetconfattr(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 	 */
 	dlmgmt_dlconf_table_lock(B_TRUE);
 
-	dlconf.ld_id = (int)unsetattr->ld_conf;
+	dlconf.ld_id = unsetattr->ld_confid;
 	dlconfp = avl_find(&dlmgmt_dlconf_avl, &dlconf, NULL);
 	if (dlconfp == NULL || zoneid != dlconfp->ld_zoneid) {
 		err = ENOENT;
@@ -795,19 +819,21 @@ done:
 }
 
 /*
- * Note that dlmgmt_readconf() returns a conf ID of a conf AVL tree entry,
+ * Note that dlmgmt_openconf() returns a conf ID of a conf AVL tree entry,
  * which is managed by dlmgmtd.  The ID is used to find the conf entry when
  * dlmgmt_write_conf() is called.  The conf entry contains an ld_gen value
  * (which is the generation number - ll_gen) of the dlmgmt_link_t at the time
- * of dlmgmt_readconf(), and ll_gen changes every time the dlmgmt_link_t
+ * of dlmgmt_openconf(), and ll_gen changes every time the dlmgmt_link_t
  * changes its attributes.  Therefore, dlmgmt_write_conf() can compare ld_gen
  * in the conf entry against the latest dlmgmt_link_t ll_gen value to see if
- * anything has changed between the dlmgmt_read_conf() and dlmgmt_writeconf()
+ * anything has changed between the dlmgmt_openconf() and dlmgmt_writeconf()
  * calls.  If so, EAGAIN is returned.  This mechanism can ensures atomicity
  * across the pair of dladm_read_conf() and dladm_write_conf() calls.
  */
+/* ARGSUSED */
 static void
-dlmgmt_writeconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_writeconf(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_writeconf_t	*writeconf = argp;
 	dlmgmt_writeconf_retval_t *retvalp = retp;
@@ -817,11 +843,11 @@ dlmgmt_writeconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 	int			err = 0;
 
 	/*
-	 * Hold the read lock to access the dlconf table.
+	 * Hold the lock to access the dlconf table.
 	 */
 	dlmgmt_dlconf_table_lock(B_TRUE);
 
-	dlconf.ld_id = (int)writeconf->ld_conf;
+	dlconf.ld_id = writeconf->ld_confid;
 	dlconfp = avl_find(&dlmgmt_dlconf_avl, &dlconf, NULL);
 	if (dlconfp == NULL || zoneid != dlconfp->ld_zoneid) {
 		err = ENOENT;
@@ -885,8 +911,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_removeconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_removeconf(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_removeconf_t 	*removeconf = argp;
 	dlmgmt_removeconf_retval_t	*retvalp = retp;
@@ -916,8 +944,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_destroyconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_destroyconf(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_destroyconf_t	*destroyconf = argp;
 	dlmgmt_destroyconf_retval_t	*retvalp = retp;
@@ -929,7 +959,7 @@ dlmgmt_destroyconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 	 */
 	dlmgmt_dlconf_table_lock(B_TRUE);
 
-	dlconf.ld_id = (int)destroyconf->ld_conf;
+	dlconf.ld_id = destroyconf->ld_confid;
 	dlconfp = avl_find(&dlmgmt_dlconf_avl, &dlconf, NULL);
 	if (dlconfp == NULL || zoneid != dlconfp->ld_zoneid) {
 		err = ENOENT;
@@ -948,17 +978,23 @@ done:
 }
 
 /*
- * See the comments above dladm_write_conf() to see how ld_gen is used to
- * ensure atomicity across the {dlmgmt_readconf(), dlmgmt_writeconf()} pair.
+ * dlmgmt_openconf() returns a handle of the current configuration, which
+ * is then used to update the configuration by dlmgmt_writeconf(). Therefore,
+ * it requires privileges.
+ *
+ * Further, please see the comments above dladm_write_conf() to see how
+ * ld_gen is used to ensure atomicity across the {dlmgmt_openconf(),
+ * dlmgmt_writeconf()} pair.
  */
 /* ARGSUSED */
 static void
-dlmgmt_readconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_openconf(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
-	dlmgmt_door_readconf_t	*readconf = argp;
-	dlmgmt_readconf_retval_t *retvalp = retp;
+	dlmgmt_door_openconf_t	*openconf = argp;
+	dlmgmt_openconf_retval_t *retvalp = retp;
 	dlmgmt_link_t 		*linkp;
-	datalink_id_t		linkid = readconf->ld_linkid;
+	datalink_id_t		linkid = openconf->ld_linkid;
 	dlmgmt_dlconf_t		*dlconfp;
 	dlmgmt_linkattr_t	*attrp;
 	int			err = 0;
@@ -987,6 +1023,9 @@ dlmgmt_readconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 		goto done;
 	}
 
+	if ((err = dlmgmt_checkprivs(linkp->ll_class, cred)) != 0)
+		goto done;
+
 	if ((err = dlconf_create(linkp->ll_link, linkp->ll_linkid,
 	    linkp->ll_class, linkp->ll_media, zoneid, &dlconfp)) != 0)
 		goto done;
@@ -1002,7 +1041,7 @@ dlmgmt_readconf(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
 	avl_add(&dlmgmt_dlconf_avl, dlconfp);
 	dlmgmt_advance_dlconfid(dlconfp);
 
-	retvalp->lr_conf = (dladm_conf_t)dlconfp->ld_id;
+	retvalp->lr_confid = dlconfp->ld_id;
 done:
 	dlmgmt_table_unlock();
 	dlmgmt_dlconf_table_unlock();
@@ -1010,36 +1049,117 @@ done:
 }
 
 /*
- * Note: the caller must free *retvalpp in case of success.
+ * dlmgmt_getconfsnapshot() returns a read-only snapshot of all the
+ * configuration, and requires no privileges.
+ *
+ * If the given size cannot hold all the configuration, set the size
+ * that is needed, and return ENOSPC.
  */
 /* ARGSUSED */
 static void
-dlmgmt_getattr(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_getconfsnapshot(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
+{
+	dlmgmt_door_getconfsnapshot_t	*snapshot = argp;
+	dlmgmt_getconfsnapshot_retval_t	*retvalp = retp;
+	dlmgmt_link_t 			*linkp;
+	datalink_id_t			linkid = snapshot->ld_linkid;
+	dlmgmt_linkattr_t		*attrp;
+	char				*buf;
+	size_t				nvlsz;
+	nvlist_t			*nvl = NULL;
+	int				err = 0;
+
+	assert(*sz >= sizeof (dlmgmt_getconfsnapshot_retval_t));
+
+	/*
+	 * Hold the reader lock to access the link
+	 */
+	dlmgmt_table_lock(B_FALSE);
+	linkp = link_by_id(linkid, zoneid);
+	if ((linkp == NULL) || !(linkp->ll_flags & DLMGMT_PERSIST)) {
+		/* The persistent link configuration does not exist. */
+		err = ENOENT;
+		goto done;
+	}
+	if (linkp->ll_onloan && zoneid != GLOBAL_ZONEID) {
+		/*
+		 * The caller is in a non-global zone and the persistent
+		 * configuration belongs to the global zone.
+		 */
+		err = EACCES;
+		goto done;
+	}
+
+	err = nvlist_alloc(&nvl, NV_UNIQUE_NAME_TYPE, 0);
+	if (err != 0)
+		goto done;
+
+	for (attrp = linkp->ll_head; attrp != NULL; attrp = attrp->lp_next) {
+		if ((err = nvlist_add_byte_array(nvl, attrp->lp_name,
+		    attrp->lp_val, attrp->lp_sz)) != 0) {
+			goto done;
+		}
+	}
+
+	if ((err = nvlist_size(nvl, &nvlsz, NV_ENCODE_NATIVE)) != 0)
+		goto done;
+
+	if (nvlsz + sizeof (dlmgmt_getconfsnapshot_retval_t) > *sz) {
+		*sz = nvlsz + sizeof (dlmgmt_getconfsnapshot_retval_t);
+		err = ENOSPC;
+		goto done;
+	}
+
+	/*
+	 * pack the the nvlist into the return value.
+	 */
+	*sz = nvlsz + sizeof (dlmgmt_getconfsnapshot_retval_t);
+	retvalp->lr_nvlsz = nvlsz;
+	buf = (char *)retvalp + sizeof (dlmgmt_getconfsnapshot_retval_t);
+	err = nvlist_pack(nvl, &buf, &nvlsz, NV_ENCODE_NATIVE, 0);
+
+done:
+	dlmgmt_table_unlock();
+	nvlist_free(nvl);
+	retvalp->lr_err = err;
+}
+
+/* ARGSUSED */
+static void
+dlmgmt_getattr(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_getattr_t	*getattr = argp;
 	dlmgmt_getattr_retval_t	*retvalp = retp;
 	dlmgmt_dlconf_t		dlconf, *dlconfp;
+	int			err;
 
 	/*
 	 * Hold the read lock to access the dlconf table.
 	 */
 	dlmgmt_dlconf_table_lock(B_FALSE);
 
-	dlconf.ld_id = (int)getattr->ld_conf;
+	dlconf.ld_id = getattr->ld_confid;
 	if ((dlconfp = avl_find(&dlmgmt_dlconf_avl, &dlconf, NULL)) == NULL ||
 	    zoneid != dlconfp->ld_zoneid) {
 		retvalp->lr_err = ENOENT;
 	} else {
-		retvalp->lr_err = dlmgmt_getattr_common(&dlconfp->ld_head,
-		    getattr->ld_attr, retvalp);
+		if ((err = dlmgmt_checkprivs(dlconfp->ld_class, cred)) != 0) {
+			retvalp->lr_err = err;
+		} else {
+			retvalp->lr_err = dlmgmt_getattr_common(
+			    &dlconfp->ld_head, getattr->ld_attr, retvalp);
+		}
 	}
 
 	dlmgmt_dlconf_table_unlock();
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_upcall_linkprop_init(void *argp, void *retp, zoneid_t zoneid,
-    ucred_t *cred)
+dlmgmt_upcall_linkprop_init(void *argp, void *retp, size_t *sz,
+    zoneid_t zoneid, ucred_t *cred)
 {
 	dlmgmt_door_linkprop_init_t	*lip = argp;
 	dlmgmt_linkprop_init_retval_t	*retvalp = retp;
@@ -1068,57 +1188,10 @@ dlmgmt_upcall_linkprop_init(void *argp, void *retp, zoneid_t zoneid,
 	retvalp->lr_err = err;
 }
 
-/*
- * Get the link property that follows ld_last_attr.
- * If ld_last_attr is empty, return the first property.
- */
 /* ARGSUSED */
 static void
-dlmgmt_linkprop_getnext(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
-{
-	dlmgmt_door_linkprop_getnext_t		*getnext = argp;
-	dlmgmt_linkprop_getnext_retval_t	*retvalp = retp;
-	dlmgmt_dlconf_t				dlconf, *dlconfp;
-	char					*attr;
-	void					*attrval;
-	size_t					attrsz;
-	dladm_datatype_t			attrtype;
-	int					err = 0;
-
-	/*
-	 * Hold the read lock to access the dlconf table.
-	 */
-	dlmgmt_dlconf_table_lock(B_FALSE);
-
-	dlconf.ld_id = (int)getnext->ld_conf;
-	dlconfp = avl_find(&dlmgmt_dlconf_avl, &dlconf, NULL);
-	if (dlconfp == NULL) {
-		err = ENOENT;
-		goto done;
-	}
-
-	err = linkprop_getnext(&dlconfp->ld_head, getnext->ld_last_attr,
-	    &attr, &attrval, &attrsz, &attrtype);
-	if (err != 0)
-		goto done;
-
-	if (attrsz > MAXLINKATTRVALLEN) {
-		err = EINVAL;
-		goto done;
-	}
-
-	(void) strlcpy(retvalp->lr_attr, attr, MAXLINKATTRLEN);
-	retvalp->lr_type = attrtype;
-	retvalp->lr_attrsz = attrsz;
-	bcopy(attrval, retvalp->lr_attrval, attrsz);
-
-done:
-	dlmgmt_dlconf_table_unlock();
-	retvalp->lr_err = err;
-}
-
-static void
-dlmgmt_setzoneid(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_setzoneid(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	dlmgmt_door_setzoneid_t	*setzoneid = argp;
 	dlmgmt_setzoneid_retval_t *retvalp = retp;
@@ -1196,8 +1269,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_zoneboot(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_zoneboot(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	int			err;
 	dlmgmt_door_zoneboot_t	*zoneboot = argp;
@@ -1226,8 +1301,10 @@ done:
 	retvalp->lr_err = err;
 }
 
+/* ARGSUSED */
 static void
-dlmgmt_zonehalt(void *argp, void *retp, zoneid_t zoneid, ucred_t *cred)
+dlmgmt_zonehalt(void *argp, void *retp, size_t *sz, zoneid_t zoneid,
+    ucred_t *cred)
 {
 	int			err = 0;
 	dlmgmt_door_zonehalt_t	*zonehalt = argp;
@@ -1270,8 +1347,8 @@ static dlmgmt_door_info_t i_dlmgmt_door_info_tbl[] = {
 	    sizeof (dlmgmt_remapid_retval_t), dlmgmt_remapid },
 	{ DLMGMT_CMD_CREATECONF, sizeof (dlmgmt_door_createconf_t),
 	    sizeof (dlmgmt_createconf_retval_t), dlmgmt_createconf },
-	{ DLMGMT_CMD_READCONF, sizeof (dlmgmt_door_readconf_t),
-	    sizeof (dlmgmt_readconf_retval_t), dlmgmt_readconf },
+	{ DLMGMT_CMD_OPENCONF, sizeof (dlmgmt_door_openconf_t),
+	    sizeof (dlmgmt_openconf_retval_t), dlmgmt_openconf },
 	{ DLMGMT_CMD_WRITECONF, sizeof (dlmgmt_door_writeconf_t),
 	    sizeof (dlmgmt_writeconf_retval_t), dlmgmt_writeconf },
 	{ DLMGMT_CMD_UP_LINKID, sizeof (dlmgmt_door_upid_t),
@@ -1286,12 +1363,11 @@ static dlmgmt_door_info_t i_dlmgmt_door_info_tbl[] = {
 	    sizeof (dlmgmt_destroyconf_retval_t), dlmgmt_destroyconf },
 	{ DLMGMT_CMD_GETATTR, sizeof (dlmgmt_door_getattr_t),
 	    sizeof (dlmgmt_getattr_retval_t), dlmgmt_getattr },
+	{ DLMGMT_CMD_GETCONFSNAPSHOT, sizeof (dlmgmt_door_getconfsnapshot_t),
+	    sizeof (dlmgmt_getconfsnapshot_retval_t), dlmgmt_getconfsnapshot },
 	{ DLMGMT_CMD_LINKPROP_INIT, sizeof (dlmgmt_door_linkprop_init_t),
 	    sizeof (dlmgmt_linkprop_init_retval_t),
 	    dlmgmt_upcall_linkprop_init },
-	{ DLMGMT_CMD_LINKPROP_GETNEXT, sizeof (dlmgmt_door_linkprop_getnext_t),
-	    sizeof (dlmgmt_linkprop_getnext_retval_t),
-	    dlmgmt_linkprop_getnext },
 	{ DLMGMT_CMD_SETZONEID, sizeof (dlmgmt_door_setzoneid_t),
 	    sizeof (dlmgmt_setzoneid_retval_t), dlmgmt_setzoneid },
 	{ DLMGMT_CMD_ZONEBOOT, sizeof (dlmgmt_door_zoneboot_t),
@@ -1324,7 +1400,8 @@ dlmgmt_handler(void *cookie, char *argp, size_t argsz, door_desc_t *dp,
 	dlmgmt_retval_t		retval;
 	ucred_t			*cred = NULL;
 	zoneid_t		zoneid;
-	void			*retvalp;
+	void			*retvalp = NULL;
+	size_t			sz, acksz;
 	int			err = 0;
 
 	infop = dlmgmt_getcmdinfo(door_arg->ld_cmd);
@@ -1339,17 +1416,31 @@ dlmgmt_handler(void *cookie, char *argp, size_t argsz, door_desc_t *dp,
 	}
 
 	/*
-	 * We cannot use malloc() here because door_return never returns, and
-	 * memory allocated by malloc() would get leaked. Use alloca() instead.
+	 * Note that malloc() cannot be used here because door_return
+	 * never returns, and memory allocated by malloc() would get leaked.
+	 * Use alloca() instead.
 	 */
-	retvalp = alloca(infop->di_acksz);
-	infop->di_handler(argp, retvalp, zoneid, cred);
+	acksz = infop->di_acksz;
+
+again:
+	retvalp = alloca(acksz);
+	sz = acksz;
+	infop->di_handler(argp, retvalp, &acksz, zoneid, cred);
+	if (acksz > sz) {
+		/*
+		 * If the specified buffer size is not big enough to hold the
+		 * return value, reallocate the buffer and try to get the
+		 * result one more time.
+		 */
+		assert(((dlmgmt_retval_t *)retvalp)->lr_err == ENOSPC);
+		goto again;
+	}
 
 done:
 	if (cred != NULL)
 		ucred_free(cred);
 	if (err == 0) {
-		(void) door_return(retvalp, infop->di_acksz, NULL, 0);
+		(void) door_return(retvalp, acksz, NULL, 0);
 	} else {
 		retval.lr_err = err;
 		(void) door_return((char *)&retval, sizeof (retval), NULL, 0);
diff --git a/usr/src/cmd/dlmgmtd/dlmgmt_impl.h b/usr/src/cmd/dlmgmtd/dlmgmt_impl.h
index eb7f6410b2..cdfd0d8a4d 100644
--- a/usr/src/cmd/dlmgmtd/dlmgmt_impl.h
+++ b/usr/src/cmd/dlmgmtd/dlmgmt_impl.h
@@ -20,8 +20,7 @@
  */
 
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 /*
@@ -103,8 +102,7 @@ int		linkattr_set(dlmgmt_linkattr_t **, const char *, void *,
 		    size_t, dladm_datatype_t);
 int		linkattr_get(dlmgmt_linkattr_t **, const char *, void **,
 		    size_t *, dladm_datatype_t *);
-int		linkprop_getnext(dlmgmt_linkattr_t **, const char *,
-		    char **, void **, size_t *, dladm_datatype_t *);
+void		linkattr_destroy(dlmgmt_link_t *);
 
 void		link_destroy(dlmgmt_link_t *);
 int		link_activate(dlmgmt_link_t *);
diff --git a/usr/src/cmd/dlmgmtd/dlmgmt_util.c b/usr/src/cmd/dlmgmtd/dlmgmt_util.c
index 58e44b9182..96b2b3b826 100644
--- a/usr/src/cmd/dlmgmtd/dlmgmt_util.c
+++ b/usr/src/cmd/dlmgmtd/dlmgmt_util.c
@@ -20,8 +20,7 @@
  */
 
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 /*
@@ -275,8 +274,11 @@ linkattr_unset(dlmgmt_linkattr_t **headp, const char *attr)
 {
 	dlmgmt_linkattr_t *attrp;
 
-	if ((attrp = linkattr_find(*headp, attr)) != NULL)
+	if ((attrp = linkattr_find(*headp, attr)) != NULL) {
 		linkattr_rm(headp, attrp);
+		free(attrp->lp_val);
+		free(attrp);
+	}
 }
 
 int
@@ -295,33 +297,6 @@ linkattr_get(dlmgmt_linkattr_t **headp, const char *attr, void **attrvalp,
 	return (0);
 }
 
-int
-linkprop_getnext(dlmgmt_linkattr_t **headp, const char *lastattr,
-    char **attrnamep, void **attrvalp, size_t *attrszp, dladm_datatype_t *typep)
-{
-	dlmgmt_linkattr_t	*attrp;
-
-	/* skip to entry following lastattr or pick first if none specified */
-	for (attrp = *headp; attrp != NULL; attrp = attrp->lp_next) {
-		if (!attrp->lp_linkprop)
-			continue;
-		if (lastattr[0] == '\0')
-			break;
-		if (strcmp(attrp->lp_name, lastattr) == 0) {
-			attrp = attrp->lp_next;
-			break;
-		}
-	}
-	if (attrp == NULL)
-		return (ENOENT);
-
-	*attrnamep = attrp->lp_name;
-	*attrvalp = attrp->lp_val;
-	*attrszp = attrp->lp_sz;
-	*typep = attrp->lp_type;
-	return (0);
-}
-
 boolean_t
 linkattr_equal(dlmgmt_linkattr_t **headp, const char *attr, void *attrval,
     size_t attrsz)
@@ -336,6 +311,18 @@ linkattr_equal(dlmgmt_linkattr_t **headp, const char *attr, void *attrval,
 	    (memcmp(saved_attrval, attrval, attrsz) == 0));
 }
 
+void
+linkattr_destroy(dlmgmt_link_t *linkp)
+{
+	dlmgmt_linkattr_t *next, *attrp;
+
+	for (attrp = linkp->ll_head; attrp != NULL; attrp = next) {
+		next = attrp->lp_next;
+		free(attrp->lp_val);
+		free(attrp);
+	}
+}
+
 static int
 dlmgmt_table_readwritelock(boolean_t write)
 {
@@ -367,13 +354,7 @@ dlmgmt_table_unlock(void)
 void
 link_destroy(dlmgmt_link_t *linkp)
 {
-	dlmgmt_linkattr_t *next, *attrp;
-
-	for (attrp = linkp->ll_head; attrp != NULL; attrp = next) {
-		next = attrp->lp_next;
-		free(attrp->lp_val);
-		free(attrp);
-	}
+	linkattr_destroy(linkp);
 	free(linkp);
 }
 
diff --git a/usr/src/cmd/rcm_daemon/common/vlan_rcm.c b/usr/src/cmd/rcm_daemon/common/vlan_rcm.c
index 31d9cd7358..83a5ea7982 100644
--- a/usr/src/cmd/rcm_daemon/common/vlan_rcm.c
+++ b/usr/src/cmd/rcm_daemon/common/vlan_rcm.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 /*
@@ -314,7 +313,8 @@ vlan_offline(rcm_handle_t *hd, char *rsrc, id_t id, uint_t flags,
 	node = cache_lookup(hd, rsrc, CACHE_REFRESH);
 	if (node == NULL) {
 		/* should not happen because the resource is registered. */
-		vlan_log_err(node->vc_linkid, errorp, "unrecognized resource");
+		vlan_log_err(DATALINK_INVALID_LINKID, errorp,
+		    "unrecognized resource");
 		(void) mutex_unlock(&cache_lock);
 		return (RCM_SUCCESS);
 	}
diff --git a/usr/src/cmd/rcm_daemon/common/vnic_rcm.c b/usr/src/cmd/rcm_daemon/common/vnic_rcm.c
index 42d80667b9..18bd4118a9 100644
--- a/usr/src/cmd/rcm_daemon/common/vnic_rcm.c
+++ b/usr/src/cmd/rcm_daemon/common/vnic_rcm.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 /*
@@ -314,7 +313,8 @@ vnic_offline(rcm_handle_t *hd, char *rsrc, id_t id, uint_t flags,
 	node = cache_lookup(hd, rsrc, CACHE_REFRESH);
 	if (node == NULL) {
 		/* should not happen because the resource is registered. */
-		vnic_log_err(node->vc_linkid, errorp, "unrecognized resource");
+		vnic_log_err(DATALINK_INVALID_LINKID, errorp,
+		    "unrecognized resource");
 		(void) mutex_unlock(&cache_lock);
 		return (RCM_SUCCESS);
 	}
diff --git a/usr/src/lib/libdladm/common/libdladm.h b/usr/src/lib/libdladm/common/libdladm.h
index eb3ca9c225..f0811ae5df 100644
--- a/usr/src/lib/libdladm/common/libdladm.h
+++ b/usr/src/lib/libdladm/common/libdladm.h
@@ -28,6 +28,7 @@
 #include <sys/dls_mgmt.h>
 #include <sys/dld.h>
 #include <sys/dlpi.h>
+#include <libnvpair.h>
 
 /*
  * This file includes structures, macros and common routines shared by all
@@ -180,7 +181,17 @@ typedef enum {
 	DLADM_TYPE_UINT64
 } dladm_datatype_t;
 
-typedef int dladm_conf_t;
+typedef struct {
+	boolean_t	ds_readonly;
+	union {
+		int	dsu_confid;
+		nvlist_t *dsu_nvl;
+	} ds_u;
+} dladm_conf_t;
+
+#define	ds_confid	ds_u.dsu_confid
+#define	ds_nvl		ds_u.dsu_nvl
+
 #define	DLADM_INVALID_CONF	0
 
 /* opaque dladm handle to libdladm functions */
diff --git a/usr/src/lib/libdladm/common/libdlaggr.c b/usr/src/lib/libdladm/common/libdlaggr.c
index 8c91c41ce1..d54920d432 100644
--- a/usr/src/lib/libdladm/common/libdlaggr.c
+++ b/usr/src/lib/libdladm/common/libdlaggr.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #include <stdio.h>
@@ -276,7 +275,7 @@ i_dladm_aggr_info_persist(dladm_handle_t handle, datalink_id_t linkid,
 	char		macstr[ETHERADDRL * 3];
 
 	attrp->lg_linkid = linkid;
-	if ((status = dladm_read_conf(handle, linkid, &conf)) !=
+	if ((status = dladm_getsnap_conf(handle, linkid, &conf)) !=
 	    DLADM_STATUS_OK)
 		return (status);
 
@@ -413,7 +412,7 @@ i_dladm_aggr_add_rmv(dladm_handle_t handle, datalink_id_t linkid,
 	 * PORT_DELIMITER (':').
 	 */
 	if (flags & DLADM_OPT_PERSIST) {
-		status = dladm_read_conf(handle, linkid, &conf);
+		status = dladm_open_conf(handle, linkid, &conf);
 		if (status != DLADM_STATUS_OK)
 			return (status);
 
@@ -573,7 +572,7 @@ done:
 	 * persistent configuration if we've changed that.
 	 */
 	if ((status != DLADM_STATUS_OK) && (flags & DLADM_OPT_PERSIST)) {
-		if (dladm_read_conf(handle, linkid, &conf) == DLADM_STATUS_OK) {
+		if (dladm_open_conf(handle, linkid, &conf) == DLADM_STATUS_OK) {
 			u64 = orig_nports;
 			if ((dladm_set_conf_field(handle, conf, FNPORTS,
 			    DLADM_TYPE_UINT64, &u64) == DLADM_STATUS_OK) &&
@@ -1013,7 +1012,7 @@ dladm_aggr_persist_aggr_conf(dladm_handle_t handle, const char *link,
     const uchar_t *mac_addr, aggr_lacp_mode_t lacp_mode,
     aggr_lacp_timer_t lacp_timer, boolean_t force)
 {
-	dladm_conf_t conf = DLADM_INVALID_CONF;
+	dladm_conf_t conf;
 	char *portstr = NULL;
 	char macstr[ETHERADDRL * 3];
 	dladm_status_t status;
@@ -1302,7 +1301,7 @@ dladm_aggr_modify(dladm_handle_t handle, datalink_id_t linkid,
 	bcopy(mac_addr, new_attr.ld_mac, ETHERADDRL);
 
 	if (flags & DLADM_OPT_PERSIST) {
-		status = dladm_read_conf(handle, linkid, &conf);
+		status = dladm_open_conf(handle, linkid, &conf);
 		if (status != DLADM_STATUS_OK)
 			return (status);
 
@@ -1330,7 +1329,7 @@ done:
 	status = i_dladm_aggr_modify_sys(handle, linkid, modify_mask,
 	    &new_attr);
 	if ((status != DLADM_STATUS_OK) && (flags & DLADM_OPT_PERSIST)) {
-		if (dladm_read_conf(handle, linkid, &conf) == DLADM_STATUS_OK) {
+		if (dladm_open_conf(handle, linkid, &conf) == DLADM_STATUS_OK) {
 			if (i_dladm_aggr_set_aggr_attr(handle, conf,
 			    modify_mask, &old_attr) == DLADM_STATUS_OK) {
 				(void) dladm_write_conf(handle, conf);
@@ -1463,7 +1462,7 @@ i_dladm_walk_key2linkid(dladm_handle_t handle, datalink_id_t linkid, void *arg)
 	i_walk_key_state_t *statep = (i_walk_key_state_t *)arg;
 	uint64_t u64;
 
-	if (dladm_read_conf(handle, linkid, &conf) != 0)
+	if (dladm_getsnap_conf(handle, linkid, &conf) != DLADM_STATUS_OK)
 		return (DLADM_WALK_CONTINUE);
 
 	status = dladm_get_conf_field(handle, conf, FKEY, &u64, sizeof (u64));
diff --git a/usr/src/lib/libdladm/common/libdlbridge.c b/usr/src/lib/libdladm/common/libdlbridge.c
index 5ad371ae93..bbf8fe762e 100644
--- a/usr/src/lib/libdladm/common/libdlbridge.c
+++ b/usr/src/lib/libdladm/common/libdlbridge.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #include <stdio.h>
@@ -624,7 +623,7 @@ static dladm_status_t
 dladm_bridge_persist_conf(dladm_handle_t handle, const char *link,
     datalink_id_t linkid)
 {
-	dladm_conf_t conf = DLADM_INVALID_CONF;
+	dladm_conf_t conf;
 	dladm_status_t status;
 
 	status = dladm_create_conf(handle, link, linkid, DATALINK_CLASS_BRIDGE,
@@ -1050,8 +1049,8 @@ dladm_bridge_setlink(dladm_handle_t handle, datalink_id_t linkid,
 	if (*bridge != '\0' && !dladm_valid_bridgename(bridge))
 		return (DLADM_STATUS_FAILED);
 
-	if ((status = dladm_read_conf(handle, linkid, &conf)) !=
-	    DLADM_STATUS_OK)
+	status = dladm_open_conf(handle, linkid, &conf);
+	if (status != DLADM_STATUS_OK)
 		return (status);
 
 	has_oldbridge = B_FALSE;
@@ -1105,7 +1104,7 @@ dladm_bridge_getlink(dladm_handle_t handle, datalink_id_t linkid, char *bridge,
 	dladm_status_t status;
 	dladm_conf_t conf;
 
-	if ((status = dladm_read_conf(handle, linkid, &conf)) !=
+	if ((status = dladm_getsnap_conf(handle, linkid, &conf)) !=
 	    DLADM_STATUS_OK)
 		return (status);
 
@@ -1143,9 +1142,9 @@ i_dladm_bridge_is_held(dladm_handle_t handle, datalink_id_t linkid, void *arg)
 	dladm_status_t status = DLADM_STATUS_FAILED;
 	dladm_conf_t conf;
 	char bridge[MAXLINKNAMELEN];
-	bridge_held_arg_t	*bha = arg;
+	bridge_held_arg_t *bha = arg;
 
-	if ((status = dladm_read_conf(handle, linkid, &conf)) !=
+	if ((status = dladm_getsnap_conf(handle, linkid, &conf)) !=
 	    DLADM_STATUS_OK)
 		return (DLADM_WALK_CONTINUE);
 	status = dladm_get_conf_field(handle, conf, FBRIDGE, bridge,
diff --git a/usr/src/lib/libdladm/common/libdlib.c b/usr/src/lib/libdladm/common/libdlib.c
index 24cbd81d54..27ec4cf6cd 100644
--- a/usr/src/lib/libdladm/common/libdlib.c
+++ b/usr/src/lib/libdladm/common/libdlib.c
@@ -171,7 +171,7 @@ i_dladm_part_info_persist(dladm_handle_t handle, datalink_id_t linkid,
 
 	bzero(attrp, sizeof (*attrp));
 	attrp->dia_partlinkid = linkid;
-	if ((status = dladm_read_conf(handle, linkid, &conf)) !=
+	if ((status = dladm_getsnap_conf(handle, linkid, &conf)) !=
 	    DLADM_STATUS_OK)
 		return (status);
 
@@ -622,7 +622,7 @@ i_dladm_part_up(dladm_handle_t handle, datalink_id_t plinkid, void *arg)
 	 * persistent configuration entry for this datalink ID. If this datalink
 	 * ID is not present in the persistent configuration return.
 	 */
-	if ((status = dladm_read_conf(handle, plinkid, &conf)) !=
+	if ((status = dladm_getsnap_conf(handle, plinkid, &conf)) !=
 	    DLADM_STATUS_OK)
 		return (status);
 
@@ -679,7 +679,7 @@ i_dladm_part_up(dladm_handle_t handle, datalink_id_t plinkid, void *arg)
 	/* Create the active IB Partition object. */
 	if (i_dladm_part_create(handle, &pattr) == DLADM_STATUS_OK &&
 	    dladm_up_datalink_id(handle, plinkid) != DLADM_STATUS_OK)
-			(void) i_dladm_part_delete(handle, linkid);
+		(void) i_dladm_part_delete(handle, linkid);
 
 done:
 	dladm_destroy_conf(handle, conf);
diff --git a/usr/src/lib/libdladm/common/libdliptun.c b/usr/src/lib/libdladm/common/libdliptun.c
index f73c0d1ecb..21c4f5dbd1 100644
--- a/usr/src/lib/libdladm/common/libdliptun.c
+++ b/usr/src/lib/libdladm/common/libdliptun.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #include <assert.h>
@@ -252,9 +251,10 @@ i_iptun_get_dbparams(dladm_handle_t handle, iptun_params_t *params)
 	if (class != DATALINK_CLASS_IPTUN)
 		return (DLADM_STATUS_LINKINVAL);
 
-	status = dladm_read_conf(handle, params->iptun_param_linkid, &conf);
-	if (status != DLADM_STATUS_OK)
+	if ((status = dladm_getsnap_conf(handle, params->iptun_param_linkid,
+	    &conf)) != DLADM_STATUS_OK) {
 		return (status);
+	}
 
 	params->iptun_param_flags = 0;
 
@@ -374,7 +374,7 @@ i_iptun_modify_db(dladm_handle_t handle, const iptun_params_t *params)
 	if (params->iptun_param_flags & ~(IPTUN_PARAM_LADDR|IPTUN_PARAM_RADDR))
 		return (DLADM_STATUS_BADARG);
 
-	status = dladm_read_conf(handle, params->iptun_param_linkid, &conf);
+	status = dladm_open_conf(handle, params->iptun_param_linkid, &conf);
 	if (status != DLADM_STATUS_OK)
 		return (status);
 
diff --git a/usr/src/lib/libdladm/common/libdllink.c b/usr/src/lib/libdladm/common/libdllink.c
index 159df78068..8a3c5759ee 100644
--- a/usr/src/lib/libdladm/common/libdllink.c
+++ b/usr/src/lib/libdladm/common/libdllink.c
@@ -523,7 +523,7 @@ i_dladm_rename_link_c2(dladm_handle_t handle, datalink_id_t linkid1,
 	(void) dladm_set_linkprop(handle, linkid1, NULL, NULL, 0,
 	    DLADM_OPT_ACTIVE);
 
-	if (((status = dladm_read_conf(handle, linkid1, &conf1)) !=
+	if (((status = dladm_getsnap_conf(handle, linkid1, &conf1)) !=
 	    DLADM_STATUS_OK) ||
 	    ((status = dladm_get_conf_field(handle, conf1, FDEVNAME, devname,
 	    MAXLINKNAMELEN)) != DLADM_STATUS_OK) ||
@@ -531,7 +531,7 @@ i_dladm_rename_link_c2(dladm_handle_t handle, datalink_id_t linkid1,
 	    sizeof (uint64_t))) != DLADM_STATUS_OK) ||
 	    ((status = dladm_get_conf_field(handle, conf1, FPHYINST, &phyinst,
 	    sizeof (uint64_t))) != DLADM_STATUS_OK) ||
-	    ((status = dladm_read_conf(handle, linkid2, &conf2)) !=
+	    ((status = dladm_open_conf(handle, linkid2, &conf2)) !=
 	    DLADM_STATUS_OK)) {
 		dir.dir_linkid1 = linkid2;
 		dir.dir_linkid2 = linkid1;
@@ -601,7 +601,7 @@ i_dladm_rename_link_c3(dladm_handle_t handle, const char *link1,
 	if (!dladm_valid_linkname(link1))
 		return (DLADM_STATUS_LINKINVAL);
 
-	status = dladm_read_conf(handle, linkid2, &conf);
+	status = dladm_open_conf(handle, linkid2, &conf);
 	if (status != DLADM_STATUS_OK)
 		goto done;
 
@@ -823,7 +823,7 @@ dladm_phys_info(dladm_handle_t handle, datalink_id_t linkid,
 	case DLADM_OPT_PERSIST: {
 		dladm_conf_t	conf;
 
-		status = dladm_read_conf(handle, linkid, &conf);
+		status = dladm_getsnap_conf(handle, linkid, &conf);
 		if (status != DLADM_STATUS_OK)
 			return (status);
 
diff --git a/usr/src/lib/libdladm/common/libdllink.h b/usr/src/lib/libdladm/common/libdllink.h
index 9d5d19a898..a2830b5e37 100644
--- a/usr/src/lib/libdladm/common/libdllink.h
+++ b/usr/src/lib/libdladm/common/libdllink.h
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #ifndef _LIBDLLINK_H
@@ -180,7 +179,9 @@ extern dladm_status_t	dladm_walk_datalink_id(int (*)(dladm_handle_t,
 extern dladm_status_t	dladm_create_conf(dladm_handle_t, const char *,
 			    datalink_id_t, datalink_class_t, uint32_t,
 			    dladm_conf_t *);
-extern dladm_status_t	dladm_read_conf(dladm_handle_t, datalink_id_t,
+extern dladm_status_t	dladm_open_conf(dladm_handle_t, datalink_id_t,
+			    dladm_conf_t *);
+extern dladm_status_t	dladm_getsnap_conf(dladm_handle_t, datalink_id_t,
 			    dladm_conf_t *);
 extern dladm_status_t	dladm_write_conf(dladm_handle_t, dladm_conf_t);
 extern dladm_status_t	dladm_remove_conf(dladm_handle_t, datalink_id_t);
diff --git a/usr/src/lib/libdladm/common/libdlmgmt.c b/usr/src/lib/libdladm/common/libdlmgmt.c
index 1827bfb504..49c70b4c6e 100644
--- a/usr/src/lib/libdladm/common/libdlmgmt.c
+++ b/usr/src/lib/libdladm/common/libdlmgmt.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #include <door.h>
@@ -53,7 +52,7 @@ static size_t dladm_datatype_size[] = {
 
 static dladm_status_t
 dladm_door_call(dladm_handle_t handle, void *arg, size_t asize, void *rbuf,
-    size_t rsize)
+    size_t *rsizep)
 {
 	door_arg_t	darg;
 	int		door_fd;
@@ -64,7 +63,7 @@ dladm_door_call(dladm_handle_t handle, void *arg, size_t asize, void *rbuf,
 	darg.desc_ptr	= NULL;
 	darg.desc_num	= 0;
 	darg.rbuf	= rbuf;
-	darg.rsize	= rsize;
+	darg.rsize	= *rsizep;
 
 	/* The door descriptor is opened if it isn't already */
 	if ((status = dladm_door_fd(handle, &door_fd)) != DLADM_STATUS_OK)
@@ -77,14 +76,15 @@ dladm_door_call(dladm_handle_t handle, void *arg, size_t asize, void *rbuf,
 	if (darg.rbuf != rbuf) {
 		/*
 		 * The size of the input rbuf is not big enough so that
-		 * the door allocate the rbuf itself. In this case, simply
-		 * think something wrong with the door call.
+		 * the door allocate the rbuf itself. In this case, return
+		 * the required size to the caller.
 		 */
 		(void) munmap(darg.rbuf, darg.rsize);
+		*rsizep = darg.rsize;
 		return (DLADM_STATUS_TOOSMALL);
-	}
-	if (darg.rsize != rsize)
+	} else if (darg.rsize != *rsizep) {
 		return (DLADM_STATUS_FAILED);
+	}
 
 	return (dladm_errno2status(((dlmgmt_retval_t *)rbuf)->lr_err));
 }
@@ -101,6 +101,7 @@ dladm_create_datalink_id(dladm_handle_t handle, const char *link,
 	dlmgmt_createid_retval_t retval;
 	uint32_t		dlmgmt_flags;
 	dladm_status_t		status;
+	size_t			sz = sizeof (retval);
 
 	if (link == NULL || class == DATALINK_CLASS_ALL ||
 	    !(flags & (DLADM_OPT_ACTIVE | DLADM_OPT_PERSIST)) ||
@@ -119,7 +120,7 @@ dladm_create_datalink_id(dladm_handle_t handle, const char *link,
 	createid.ld_prefix = (flags & DLADM_OPT_PREFIX);
 
 	if ((status = dladm_door_call(handle, &createid, sizeof (createid),
-	    &retval, sizeof (retval))) == DLADM_STATUS_OK) {
+	    &retval, &sz)) == DLADM_STATUS_OK) {
 		*linkidp = retval.lr_linkid;
 	}
 	return (status);
@@ -135,6 +136,7 @@ dladm_destroy_datalink_id(dladm_handle_t handle, datalink_id_t linkid,
 	dlmgmt_door_destroyid_t		destroyid;
 	dlmgmt_destroyid_retval_t	retval;
 	uint32_t			dlmgmt_flags;
+	size_t				sz = sizeof (retval);
 
 	dlmgmt_flags = (flags & DLADM_OPT_ACTIVE) ? DLMGMT_ACTIVE : 0;
 	dlmgmt_flags |= ((flags & DLADM_OPT_PERSIST) ? DLMGMT_PERSIST : 0);
@@ -143,8 +145,8 @@ dladm_destroy_datalink_id(dladm_handle_t handle, datalink_id_t linkid,
 	destroyid.ld_linkid = linkid;
 	destroyid.ld_flags = dlmgmt_flags;
 
-	return (dladm_door_call(handle, &destroyid, sizeof (destroyid), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &destroyid, sizeof (destroyid),
+	    &retval, &sz));
 }
 
 /*
@@ -156,13 +158,14 @@ dladm_remap_datalink_id(dladm_handle_t handle, datalink_id_t linkid,
 {
 	dlmgmt_door_remapid_t	remapid;
 	dlmgmt_remapid_retval_t	retval;
+	size_t			sz = sizeof (retval);
 
 	remapid.ld_cmd = DLMGMT_CMD_REMAP_LINKID;
 	remapid.ld_linkid = linkid;
 	(void) strlcpy(remapid.ld_link, link, MAXLINKNAMELEN);
 
-	return (dladm_door_call(handle, &remapid, sizeof (remapid), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &remapid, sizeof (remapid),
+	    &retval, &sz));
 }
 
 /*
@@ -173,12 +176,12 @@ dladm_up_datalink_id(dladm_handle_t handle, datalink_id_t linkid)
 {
 	dlmgmt_door_upid_t	upid;
 	dlmgmt_upid_retval_t	retval;
+	size_t			sz = sizeof (retval);
 
 	upid.ld_cmd = DLMGMT_CMD_UP_LINKID;
 	upid.ld_linkid = linkid;
 
-	return (dladm_door_call(handle, &upid, sizeof (upid), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &upid, sizeof (upid), &retval, &sz));
 }
 
 /*
@@ -191,6 +194,7 @@ dladm_create_conf(dladm_handle_t handle, const char *link, datalink_id_t linkid,
 	dlmgmt_door_createconf_t	createconf;
 	dlmgmt_createconf_retval_t	retval;
 	dladm_status_t			status;
+	size_t				sz = sizeof (retval);
 
 	if (link == NULL || confp == NULL)
 		return (DLADM_STATUS_BADARG);
@@ -200,10 +204,12 @@ dladm_create_conf(dladm_handle_t handle, const char *link, datalink_id_t linkid,
 	createconf.ld_media = media;
 	createconf.ld_linkid = linkid;
 	createconf.ld_cmd = DLMGMT_CMD_CREATECONF;
+	confp->ds_confid = DLADM_INVALID_CONF;
 
 	if ((status = dladm_door_call(handle, &createconf, sizeof (createconf),
-	    &retval, sizeof (retval))) == DLADM_STATUS_OK) {
-		*confp = retval.lr_conf;
+	    &retval, &sz)) == DLADM_STATUS_OK) {
+		confp->ds_readonly = B_FALSE;
+		confp->ds_confid = retval.lr_confid;
 	}
 	return (status);
 }
@@ -259,6 +265,7 @@ dladm_walk_datalink_id(int (*fn)(dladm_handle_t, datalink_id_t, void *),
 	uint32_t 		dlmgmt_flags;
 	datalink_id_t		linkid = DATALINK_INVALID_LINKID;
 	dladm_status_t		status = DLADM_STATUS_OK;
+	size_t			sz = sizeof (retval);
 
 	if (fn == NULL)
 		return (DLADM_STATUS_BADARG);
@@ -274,8 +281,7 @@ dladm_walk_datalink_id(int (*fn)(dladm_handle_t, datalink_id_t, void *),
 	do {
 		getnext.ld_linkid = linkid;
 		if ((status = dladm_door_call(handle, &getnext,
-		    sizeof (getnext), &retval, sizeof (retval))) !=
-		    DLADM_STATUS_OK) {
+		    sizeof (getnext), &retval, &sz)) != DLADM_STATUS_OK) {
 			/*
 			 * Done with walking. If no next datalink is found,
 			 * return success.
@@ -310,26 +316,78 @@ dladm_walk_datalink_id(int (*fn)(dladm_handle_t, datalink_id_t, void *),
 }
 
 /*
- * Get the link properties structure for the given link.
+ * Get a handle of a copy of the link configuration (kept in the daemon)
+ * for the given link so it can be updated later by dladm_write_conf().
+ */
+dladm_status_t
+dladm_open_conf(dladm_handle_t handle, datalink_id_t linkid,
+    dladm_conf_t *confp)
+{
+	dlmgmt_door_openconf_t		openconf;
+	dlmgmt_openconf_retval_t	retval;
+	dladm_status_t			status;
+	size_t				sz;
+
+	if (linkid == DATALINK_INVALID_LINKID || confp == NULL)
+		return (DLADM_STATUS_BADARG);
+
+	sz = sizeof (retval);
+	openconf.ld_linkid = linkid;
+	openconf.ld_cmd = DLMGMT_CMD_OPENCONF;
+	confp->ds_confid = DLADM_INVALID_CONF;
+	if ((status = dladm_door_call(handle, &openconf,
+	    sizeof (openconf), &retval, &sz)) == DLADM_STATUS_OK) {
+		confp->ds_readonly = B_FALSE;
+		confp->ds_confid = retval.lr_confid;
+	}
+
+	return (status);
+}
+
+/*
+ * Get the handle of a local snapshot of the link configuration. Note that
+ * any operations with this handle are read-only, i.e., one can not update
+ * the configuration with this handle.
  */
 dladm_status_t
-dladm_read_conf(dladm_handle_t handle, datalink_id_t linkid,
+dladm_getsnap_conf(dladm_handle_t handle, datalink_id_t linkid,
     dladm_conf_t *confp)
 {
-	dlmgmt_door_readconf_t		readconf;
-	dlmgmt_readconf_retval_t	retval;
+	dlmgmt_door_getconfsnapshot_t	snapshot;
+	dlmgmt_getconfsnapshot_retval_t	*retvalp;
+	char				*nvlbuf;
 	dladm_status_t			status;
+	int				err;
+	size_t				sz;
 
 	if (linkid == DATALINK_INVALID_LINKID || confp == NULL)
 		return (DLADM_STATUS_BADARG);
 
-	readconf.ld_linkid = linkid;
-	readconf.ld_cmd = DLMGMT_CMD_READCONF;
+	sz = sizeof (dlmgmt_getconfsnapshot_retval_t);
+	snapshot.ld_linkid = linkid;
+	snapshot.ld_cmd = DLMGMT_CMD_GETCONFSNAPSHOT;
+again:
+	if ((retvalp = malloc(sz)) == NULL)
+		return (DLADM_STATUS_NOMEM);
+
+	if ((status = dladm_door_call(handle, &snapshot, sizeof (snapshot),
+	    retvalp, &sz)) == DLADM_STATUS_TOOSMALL) {
+		free(retvalp);
+		goto again;
+	}
+
+	if (status != DLADM_STATUS_OK) {
+		free(retvalp);
+		return (status);
+	}
 
-	if ((status = dladm_door_call(handle, &readconf, sizeof (readconf),
-	    &retval, sizeof (retval))) == DLADM_STATUS_OK) {
-		*confp = retval.lr_conf;
+	confp->ds_readonly = B_TRUE;
+	nvlbuf = (char *)retvalp + sizeof (dlmgmt_getconfsnapshot_retval_t);
+	if ((err = nvlist_unpack(nvlbuf, retvalp->lr_nvlsz,
+	    &(confp->ds_nvl), NV_ENCODE_NATIVE)) != 0) {
+		status = dladm_errno2status(err);
 	}
+	free(retvalp);
 	return (status);
 }
 
@@ -342,83 +400,117 @@ dladm_write_conf(dladm_handle_t handle, dladm_conf_t conf)
 {
 	dlmgmt_door_writeconf_t		writeconf;
 	dlmgmt_writeconf_retval_t	retval;
+	size_t				sz = sizeof (retval);
 
-	if (conf == DLADM_INVALID_CONF)
+	if (conf.ds_confid == DLADM_INVALID_CONF)
 		return (DLADM_STATUS_BADARG);
 
+	if (conf.ds_readonly)
+		return (DLADM_STATUS_DENIED);
+
 	writeconf.ld_cmd = DLMGMT_CMD_WRITECONF;
-	writeconf.ld_conf = conf;
+	writeconf.ld_confid = conf.ds_confid;
 
-	return (dladm_door_call(handle, &writeconf, sizeof (writeconf), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &writeconf, sizeof (writeconf),
+	    &retval, &sz));
 }
 
 /*
- * Given a link ID and a key, get the matching information from
- * data link configuration repository.
+ * Given a dladm_conf_t, get the specific configuration field
+ *
+ * If the specified dladm_conf_t is a read-only snapshot of the configuration,
+ * get a specific link propertie from that snapshot (nvl), otherwise, get
+ * the link protperty from the dlmgmtd daemon using the given confid.
  */
 dladm_status_t
 dladm_get_conf_field(dladm_handle_t handle, dladm_conf_t conf, const char *attr,
     void *attrval, size_t attrsz)
 {
-	dlmgmt_door_getattr_t	getattr;
-	dlmgmt_getattr_retval_t	retval;
-	dladm_status_t		status;
+	dladm_status_t		status = DLADM_STATUS_OK;
 
-	if (conf == DLADM_INVALID_CONF || attrval == NULL ||
-	    attrsz == 0 || attr == NULL) {
+	if (attrval == NULL || attrsz == 0 || attr == NULL)
 		return (DLADM_STATUS_BADARG);
-	}
 
-	getattr.ld_cmd = DLMGMT_CMD_GETATTR;
-	getattr.ld_conf = conf;
-	(void) strlcpy(getattr.ld_attr, attr, MAXLINKATTRLEN);
+	if (conf.ds_readonly) {
+		uchar_t		*oattrval;
+		uint32_t	oattrsz;
+		int		err;
 
-	if ((status = dladm_door_call(handle, &getattr, sizeof (getattr),
-	    &retval, sizeof (retval))) != DLADM_STATUS_OK) {
-		return (status);
-	}
+		if ((err = nvlist_lookup_byte_array(conf.ds_nvl, (char *)attr,
+		    &oattrval, &oattrsz)) != 0) {
+			return (dladm_errno2status(err));
+		}
+		if (oattrsz > attrsz)
+			return (DLADM_STATUS_TOOSMALL);
 
-	if (retval.lr_attrsz > attrsz)
-		return (DLADM_STATUS_TOOSMALL);
+		bcopy(oattrval, attrval, oattrsz);
+	} else {
+		dlmgmt_door_getattr_t	getattr;
+		dlmgmt_getattr_retval_t	retval;
+		size_t			sz = sizeof (retval);
 
-	bcopy(retval.lr_attrval, attrval, retval.lr_attrsz);
-	return (DLADM_STATUS_OK);
+		if (conf.ds_confid == DLADM_INVALID_CONF)
+			return (DLADM_STATUS_BADARG);
+
+		getattr.ld_cmd = DLMGMT_CMD_GETATTR;
+		getattr.ld_confid = conf.ds_confid;
+		(void) strlcpy(getattr.ld_attr, attr, MAXLINKATTRLEN);
+
+		if ((status = dladm_door_call(handle, &getattr,
+		    sizeof (getattr), &retval, &sz)) != DLADM_STATUS_OK) {
+			return (status);
+		}
+
+		if (retval.lr_attrsz > attrsz)
+			return (DLADM_STATUS_TOOSMALL);
+
+		bcopy(retval.lr_attrval, attrval, retval.lr_attrsz);
+	}
+	return (status);
 }
 
 /*
  * Get next property attribute from data link configuration repository.
+ * If last_attr is "", return the first property.
  */
+/* ARGSUSED */
 dladm_status_t
 dladm_getnext_conf_linkprop(dladm_handle_t handle, dladm_conf_t conf,
     const char *last_attr, char *attr, void *attrval, size_t attrsz,
     size_t *attrszp)
 {
-	dlmgmt_door_linkprop_getnext_t		getnext;
-	dlmgmt_linkprop_getnext_retval_t	retval;
-	dladm_status_t				status;
-
-	if (conf == DLADM_INVALID_CONF || attrval == NULL ||
-	    attrsz == 0 || attr == NULL) {
+	nvlist_t	*nvl = conf.ds_nvl;
+	nvpair_t	*last = NULL, *nvp;
+	uchar_t		*oattrval;
+	uint32_t	oattrsz;
+	int		err;
+
+	if (nvl == NULL || attrval == NULL || attrsz == 0 || attr == NULL ||
+	    !conf.ds_readonly)
 		return (DLADM_STATUS_BADARG);
+
+	while ((nvp = nvlist_next_nvpair(nvl, last)) != NULL) {
+		if (last_attr[0] == '\0')
+			break;
+		if (last != NULL && strcmp(last_attr, nvpair_name(last)) == 0)
+			break;
+		last = nvp;
 	}
 
-	getnext.ld_cmd = DLMGMT_CMD_LINKPROP_GETNEXT;
-	getnext.ld_conf = conf;
-	(void) strlcpy(getnext.ld_last_attr, last_attr, MAXLINKATTRLEN);
+	if (nvp == NULL)
+		return (DLADM_STATUS_NOTFOUND);
 
-	if ((status = dladm_door_call(handle, &getnext, sizeof (getnext),
-	    &retval, sizeof (retval))) != DLADM_STATUS_OK) {
-		return (status);
+	if ((err = nvpair_value_byte_array(nvp, (uchar_t **)&oattrval,
+	    &oattrsz)) != NULL) {
+		return (dladm_errno2status(err));
 	}
 
-	*attrszp = retval.lr_attrsz;
-	if (retval.lr_attrsz > attrsz) {
+	*attrszp = oattrsz;
+	if (oattrsz > attrsz)
 		return (DLADM_STATUS_TOOSMALL);
-	}
 
-	(void) strlcpy(attr, retval.lr_attr, MAXLINKATTRLEN);
-	bcopy(retval.lr_attrval, attrval, retval.lr_attrsz);
+	(void) strlcpy(attr, nvpair_name(nvp), MAXLINKATTRLEN);
+	bcopy(oattrval, attrval, oattrsz);
 	return (DLADM_STATUS_OK);
 }
 
@@ -433,12 +525,13 @@ dladm_name2info(dladm_handle_t handle, const char *link, datalink_id_t *linkidp,
 	dlmgmt_getlinkid_retval_t	retval;
 	datalink_id_t			linkid;
 	dladm_status_t			status;
+	size_t				sz = sizeof (retval);
 
 	getlinkid.ld_cmd = DLMGMT_CMD_GETLINKID;
 	(void) strlcpy(getlinkid.ld_link, link, MAXLINKNAMELEN);
 
 	if ((status = dladm_door_call(handle, &getlinkid, sizeof (getlinkid),
-	    &retval, sizeof (retval))) != DLADM_STATUS_OK) {
+	    &retval, &sz)) != DLADM_STATUS_OK) {
 		return (status);
 	}
 
@@ -480,6 +573,7 @@ dladm_datalink_id2info(dladm_handle_t handle, datalink_id_t linkid,
 	dlmgmt_door_getname_t	getname;
 	dlmgmt_getname_retval_t	retval;
 	dladm_status_t		status;
+	size_t			sz = sizeof (retval);
 
 	if ((linkid == DATALINK_INVALID_LINKID) || (link != NULL && len == 0) ||
 	    (link == NULL && len != 0)) {
@@ -489,7 +583,7 @@ dladm_datalink_id2info(dladm_handle_t handle, datalink_id_t linkid,
 	getname.ld_cmd = DLMGMT_CMD_GETNAME;
 	getname.ld_linkid = linkid;
 	if ((status = dladm_door_call(handle, &getname, sizeof (getname),
-	    &retval, sizeof (retval))) != DLADM_STATUS_OK) {
+	    &retval, &sz)) != DLADM_STATUS_OK) {
 		return (status);
 	}
 
@@ -532,10 +626,14 @@ dladm_set_conf_field(dladm_handle_t handle, dladm_conf_t conf, const char *attr,
 	dlmgmt_door_setattr_t	setattr;
 	dlmgmt_setattr_retval_t	retval;
 	size_t			attrsz;
+	size_t			sz = sizeof (retval);
 
 	if (attr == NULL || attrval == NULL)
 		return (DLADM_STATUS_BADARG);
 
+	if (conf.ds_readonly)
+		return (DLADM_STATUS_DENIED);
+
 	if (type == DLADM_TYPE_STR)
 		attrsz = strlen(attrval) + 1;
 	else
@@ -545,14 +643,14 @@ dladm_set_conf_field(dladm_handle_t handle, dladm_conf_t conf, const char *attr,
 		return (DLADM_STATUS_TOOSMALL);
 
 	setattr.ld_cmd = DLMGMT_CMD_SETATTR;
-	setattr.ld_conf = conf;
+	setattr.ld_confid = conf.ds_confid;
 	(void) strlcpy(setattr.ld_attr, attr, MAXLINKATTRLEN);
 	setattr.ld_attrsz = attrsz;
 	setattr.ld_type = type;
 	bcopy(attrval, &setattr.ld_attrval, attrsz);
 
-	return (dladm_door_call(handle, &setattr, sizeof (setattr), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &setattr, sizeof (setattr),
+	    &retval, &sz));
 }
 
 /*
@@ -564,16 +662,20 @@ dladm_unset_conf_field(dladm_handle_t handle, dladm_conf_t conf,
 {
 	dlmgmt_door_unsetattr_t		unsetattr;
 	dlmgmt_unsetattr_retval_t	retval;
+	size_t				sz = sizeof (retval);
 
 	if (attr == NULL)
 		return (DLADM_STATUS_BADARG);
 
+	if (conf.ds_readonly)
+		return (DLADM_STATUS_DENIED);
+
 	unsetattr.ld_cmd = DLMGMT_CMD_UNSETATTR;
-	unsetattr.ld_conf = conf;
+	unsetattr.ld_confid = conf.ds_confid;
 	(void) strlcpy(unsetattr.ld_attr, attr, MAXLINKATTRLEN);
 
-	return (dladm_door_call(handle, &unsetattr, sizeof (unsetattr), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &unsetattr, sizeof (unsetattr),
+	    &retval, &sz));
 }
 
 /*
@@ -585,12 +687,13 @@ dladm_remove_conf(dladm_handle_t handle, datalink_id_t linkid)
 {
 	dlmgmt_door_removeconf_t	removeconf;
 	dlmgmt_removeconf_retval_t	retval;
+	size_t				sz = sizeof (retval);
 
 	removeconf.ld_cmd = DLMGMT_CMD_REMOVECONF;
 	removeconf.ld_linkid = linkid;
 
 	return (dladm_door_call(handle, &removeconf, sizeof (removeconf),
-	    &retval, sizeof (retval)));
+	    &retval, &sz));
 }
 
 /*
@@ -599,17 +702,22 @@ dladm_remove_conf(dladm_handle_t handle, datalink_id_t linkid)
 void
 dladm_destroy_conf(dladm_handle_t handle, dladm_conf_t conf)
 {
-	dlmgmt_door_destroyconf_t	destroyconf;
+	dlmgmt_door_destroyconf_t	dconf;
 	dlmgmt_destroyconf_retval_t	retval;
+	size_t				sz = sizeof (retval);
 
-	if (conf == DLADM_INVALID_CONF)
-		return;
+	if (conf.ds_readonly) {
+		nvlist_free(conf.ds_nvl);
+	} else {
+		if (conf.ds_confid == DLADM_INVALID_CONF)
+			return;
 
-	destroyconf.ld_cmd = DLMGMT_CMD_DESTROYCONF;
-	destroyconf.ld_conf = conf;
+		dconf.ld_cmd = DLMGMT_CMD_DESTROYCONF;
+		dconf.ld_confid = conf.ds_confid;
 
-	(void) dladm_door_call(handle, &destroyconf, sizeof (destroyconf),
-	    &retval, sizeof (retval));
+		(void) dladm_door_call(handle, &dconf, sizeof (dconf),
+		    &retval, &sz);
+	}
 }
 
 dladm_status_t
@@ -617,11 +725,12 @@ dladm_zone_boot(dladm_handle_t handle, zoneid_t zoneid)
 {
 	dlmgmt_door_zoneboot_t		zoneboot;
 	dlmgmt_zoneboot_retval_t	retval;
+	size_t				sz = sizeof (retval);
 
 	zoneboot.ld_cmd = DLMGMT_CMD_ZONEBOOT;
 	zoneboot.ld_zoneid = zoneid;
-	return (dladm_door_call(handle, &zoneboot, sizeof (zoneboot), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &zoneboot, sizeof (zoneboot),
+	    &retval, &sz));
 }
 
 dladm_status_t
@@ -629,9 +738,10 @@ dladm_zone_halt(dladm_handle_t handle, zoneid_t zoneid)
 {
 	dlmgmt_door_zonehalt_t		zonehalt;
 	dlmgmt_zonehalt_retval_t	retval;
+	size_t				sz = sizeof (retval);
 
 	zonehalt.ld_cmd = DLMGMT_CMD_ZONEHALT;
 	zonehalt.ld_zoneid = zoneid;
-	return (dladm_door_call(handle, &zonehalt, sizeof (zonehalt), &retval,
-	    sizeof (retval)));
+	return (dladm_door_call(handle, &zonehalt, sizeof (zonehalt),
+	    &retval, &sz));
 }
diff --git a/usr/src/lib/libdladm/common/libdlmgmt.h b/usr/src/lib/libdladm/common/libdlmgmt.h
index c170629647..2e208209e8 100644
--- a/usr/src/lib/libdladm/common/libdlmgmt.h
+++ b/usr/src/lib/libdladm/common/libdlmgmt.h
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 /*
@@ -49,7 +48,7 @@ extern "C" {
 #define	DLMGMT_CMD_DESTROY_LINKID	(DLMGMT_CMD_BASE + 1)
 #define	DLMGMT_CMD_REMAP_LINKID		(DLMGMT_CMD_BASE + 2)
 #define	DLMGMT_CMD_CREATECONF		(DLMGMT_CMD_BASE + 3)
-#define	DLMGMT_CMD_READCONF		(DLMGMT_CMD_BASE + 4)
+#define	DLMGMT_CMD_OPENCONF		(DLMGMT_CMD_BASE + 4)
 #define	DLMGMT_CMD_WRITECONF		(DLMGMT_CMD_BASE + 5)
 #define	DLMGMT_CMD_UP_LINKID		(DLMGMT_CMD_BASE + 6)
 #define	DLMGMT_CMD_SETATTR		(DLMGMT_CMD_BASE + 7)
@@ -57,7 +56,7 @@ extern "C" {
 #define	DLMGMT_CMD_REMOVECONF		(DLMGMT_CMD_BASE + 9)
 #define	DLMGMT_CMD_DESTROYCONF		(DLMGMT_CMD_BASE + 10)
 #define	DLMGMT_CMD_GETATTR		(DLMGMT_CMD_BASE + 11)
-#define	DLMGMT_CMD_LINKPROP_GETNEXT	(DLMGMT_CMD_BASE + 12)
+#define	DLMGMT_CMD_GETCONFSNAPSHOT	(DLMGMT_CMD_BASE + 12)
 #define	DLMGMT_CMD_ZONEBOOT		(DLMGMT_CMD_BASE + 13)
 #define	DLMGMT_CMD_ZONEHALT		(DLMGMT_CMD_BASE + 14)
 
@@ -97,7 +96,7 @@ typedef struct dlmgmt_door_createconf_s {
 
 typedef struct dlmgmt_door_setattr_s {
 	int			ld_cmd;
-	dladm_conf_t		ld_conf;
+	int			ld_confid;
 	char			ld_attr[MAXLINKATTRLEN];
 	size_t			ld_attrsz;
 	dladm_datatype_t	ld_type;
@@ -106,13 +105,13 @@ typedef struct dlmgmt_door_setattr_s {
 
 typedef struct dlmgmt_door_unsetattr_s {
 	int		ld_cmd;
-	dladm_conf_t	ld_conf;
+	int		ld_confid;
 	char		ld_attr[MAXLINKATTRLEN];
 } dlmgmt_door_unsetattr_t;
 
 typedef struct dlmgmt_door_writeconf_s {
 	int		ld_cmd;
-	dladm_conf_t	ld_conf;
+	int		ld_confid;
 } dlmgmt_door_writeconf_t;
 
 typedef struct dlmgmt_door_removeconf_s {
@@ -122,38 +121,40 @@ typedef struct dlmgmt_door_removeconf_s {
 
 typedef struct dlmgmt_door_destroyconf_s {
 	int		ld_cmd;
-	dladm_conf_t	ld_conf;
+	int		ld_confid;
 } dlmgmt_door_destroyconf_t;
 
-typedef struct dlmgmt_door_readconf_s {
+typedef struct dlmgmt_door_openconf_s {
 	int		ld_cmd;
 	datalink_id_t	ld_linkid;
-} dlmgmt_door_readconf_t;
+} dlmgmt_door_openconf_t;
+
+typedef struct dlmgmt_door_getconfsnapshot_s {
+	int		ld_cmd;
+	datalink_id_t	ld_linkid;
+} dlmgmt_door_getconfsnapshot_t;
 
 typedef struct dlmgmt_door_getattr_s {
 	int		ld_cmd;
-	dladm_conf_t	ld_conf;
+	int		ld_confid;
 	char		ld_attr[MAXLINKATTRLEN];
 } dlmgmt_door_getattr_t;
 
-typedef struct dlmgmt_handle_retval_s {
-	uint_t			lr_err;
-	dladm_conf_t		lr_conf;
-} dlmgmt_createconf_retval_t, dlmgmt_readconf_retval_t;
-
-typedef struct dlmgmt_door_linkprop_getnext_s {
-	int			ld_cmd;
-	dladm_conf_t		ld_conf;
-	char			ld_last_attr[MAXLINKATTRLEN];
-} dlmgmt_door_linkprop_getnext_t;
-
-typedef struct dlmgmt_linkprop_getnext_retval_s {
+typedef struct dlmgmt_createconf_retval_s {
 	uint_t			lr_err;
-	char			lr_attr[MAXLINKATTRLEN];
-	uint_t			lr_type;
-	uint_t			lr_attrsz;
-	char			lr_attrval[MAXLINKATTRVALLEN];
-} dlmgmt_linkprop_getnext_retval_t;
+	int			lr_confid;
+} dlmgmt_createconf_retval_t;
+
+typedef struct dlmgmt_openconf_retval_s {
+	uint_t		lr_err;
+	int		lr_confid;
+} dlmgmt_openconf_retval_t;
+
+typedef struct dlmgmt_getconfsnapshot_retval_s {
+	uint_t		lr_err;
+	size_t		lr_nvlsz;
+	/* buffer for nvl */
+} dlmgmt_getconfsnapshot_retval_t;
 
 typedef struct dlmgmt_door_zone_s {
 	int			ld_cmd;
diff --git a/usr/src/lib/libdladm/common/libdlsim.c b/usr/src/lib/libdladm/common/libdlsim.c
index a588073bfb..7b8c515875 100644
--- a/usr/src/lib/libdladm/common/libdlsim.c
+++ b/usr/src/lib/libdladm/common/libdlsim.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #include <sys/types.h>
@@ -142,8 +141,8 @@ i_dladm_get_simnet_info_persist(dladm_handle_t handle,
 	uint64_t u64;
 	boolean_t mac_fixed;
 
-	if ((status = dladm_read_conf(handle, attrp->sna_link_id, &conf)) !=
-	    DLADM_STATUS_OK)
+	if ((status = dladm_getsnap_conf(handle, attrp->sna_link_id,
+	    &conf)) != DLADM_STATUS_OK)
 		return (status);
 
 	status = dladm_get_conf_field(handle, conf, FSIMNETTYPE, &u64,
@@ -228,7 +227,7 @@ i_dladm_simnet_update_conf(dladm_handle_t handle, datalink_id_t simnet_id,
 	dladm_conf_t conf;
 	char simnetpeer[MAXLINKNAMELEN];
 
-	status = dladm_read_conf(handle, simnet_id, &conf);
+	status = dladm_open_conf(handle, simnet_id, &conf);
 	if (status != DLADM_STATUS_OK)
 		return (status);
 
@@ -474,7 +473,7 @@ static dladm_status_t
 dladm_simnet_persist_conf(dladm_handle_t handle, const char *name,
     dladm_simnet_attr_t *attrp)
 {
-	dladm_conf_t conf = DLADM_INVALID_CONF;
+	dladm_conf_t conf;
 	dladm_status_t status;
 	char mstr[ETHERADDRL * 3];
 	uint64_t u64;
diff --git a/usr/src/lib/libdladm/common/libdlvnic.c b/usr/src/lib/libdladm/common/libdlvnic.c
index 7ff9563e1a..6dba8d6fad 100644
--- a/usr/src/lib/libdladm/common/libdlvnic.c
+++ b/usr/src/lib/libdladm/common/libdlvnic.c
@@ -19,8 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
 #include <stdio.h>
@@ -199,7 +198,7 @@ i_dladm_vnic_info_persist(dladm_handle_t handle, datalink_id_t linkid,
 	datalink_class_t class;
 
 	attrp->va_vnic_id = linkid;
-	if ((status = dladm_read_conf(handle, linkid, &conf)) !=
+	if ((status = dladm_getsnap_conf(handle, linkid, &conf)) !=
 	    DLADM_STATUS_OK)
 		return (status);
 
@@ -279,7 +278,6 @@ i_dladm_vnic_info_persist(dladm_handle_t handle, datalink_id_t linkid,
 	    sizeof (u64));
 	attrp->va_vid = ((status == DLADM_STATUS_OK) ?  (uint16_t)u64 : 0);
 
-
 	status = DLADM_STATUS_OK;
 done:
 	dladm_destroy_conf(handle, conf);
@@ -663,7 +661,7 @@ static dladm_status_t
 dladm_vnic_persist_conf(dladm_handle_t handle, const char *name,
     dladm_vnic_attr_t *attrp, datalink_class_t class)
 {
-	dladm_conf_t conf = DLADM_INVALID_CONF;
+	dladm_conf_t conf;
 	dladm_status_t status;
 	char macstr[ETHERADDRL * 3];
 	char linkover[MAXLINKNAMELEN];
diff --git a/usr/src/lib/libdladm/common/linkprop.c b/usr/src/lib/libdladm/common/linkprop.c
index b9f38012ed..4a7865d0e6 100644
--- a/usr/src/lib/libdladm/common/linkprop.c
+++ b/usr/src/lib/libdladm/common/linkprop.c
@@ -3309,7 +3309,7 @@ i_dladm_set_linkprop_db(dladm_handle_t handle, datalink_id_t linkid,
 	dladm_conf_t	conf;
 	dladm_status_t	status;
 
-	status = dladm_read_conf(handle, linkid, &conf);
+	status = dladm_open_conf(handle, linkid, &conf);
 	if (status != DLADM_STATUS_OK)
 		return (status);
 
@@ -3349,7 +3349,7 @@ i_dladm_get_linkprop_db(dladm_handle_t handle, datalink_id_t linkid,
 	dladm_conf_t	conf;
 	dladm_status_t	status;
 
-	status = dladm_read_conf(handle, linkid, &conf);
+	status = dladm_getsnap_conf(handle, linkid, &conf);
 	if (status != DLADM_STATUS_OK)
 		return (status);
 
@@ -3391,7 +3391,7 @@ i_dladm_walk_linkprop_priv_db(dladm_handle_t handle, datalink_id_t linkid,
 	if (linkid == DATALINK_INVALID_LINKID || func == NULL)
 		return (DLADM_STATUS_BADARG);
 
-	status = dladm_read_conf(handle, linkid, &conf);
+	status = dladm_getsnap_conf(handle, linkid, &conf);
 	if (status != DLADM_STATUS_OK)
 		return (status);
 
diff --git a/usr/src/lib/libdladm/common/mapfile-vers b/usr/src/lib/libdladm/common/mapfile-vers
index 10128b43a1..b781c93aff 100644
--- a/usr/src/lib/libdladm/common/mapfile-vers
+++ b/usr/src/lib/libdladm/common/mapfile-vers
@@ -137,7 +137,8 @@ SYMBOL_VERSION SUNWprivate_1.1 {
 	dladm_datalink_id2info;
 	dladm_walk_datalink_id;
 	dladm_create_conf;
-	dladm_read_conf;
+	dladm_open_conf;
+	dladm_getsnap_conf;
 	dladm_write_conf;
 	dladm_remove_conf;
 	dladm_destroy_conf;