Adding upstream version 3.1.0.upstream/3.1.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2178 insertions, 0 deletions

diff --git a/src/validation.c b/src/validation.c
new file mode 100644
index 0000000..501dd69
--- /dev/null
+++ b/src/validation.c
@@ -0,0 +1,2178 @@
+/**
+ * @file validation.c
+ * @author Michal Vasko <mvasko@cesnet.cz>
+ * @brief Validation
+ *
+ * Copyright (c) 2019 - 2023 CESNET, z.s.p.o.
+ *
+ * This source code is licensed under BSD 3-Clause License (the "License").
+ * You may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://opensource.org/licenses/BSD-3-Clause
+ */
+#define _GNU_SOURCE /* asprintf, strdup */
+
+#include "validation.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "compat.h"
+#include "diff.h"
+#include "hash_table.h"
+#include "log.h"
+#include "ly_common.h"
+#include "parser_data.h"
+#include "parser_internal.h"
+#include "plugins_exts.h"
+#include "plugins_exts/metadata.h"
+#include "plugins_types.h"
+#include "set.h"
+#include "tree.h"
+#include "tree_data.h"
+#include "tree_data_internal.h"
+#include "tree_schema.h"
+#include "tree_schema_internal.h"
+#include "xpath.h"
+
+/**
+ * @brief Check validation error taking into account multi-error validation.
+ *
+ * @param[in] r Local return value.
+ * @param[in] err_cmd Command to perform on any error.
+ * @param[in] val_opts Validation options.
+ * @param[in] label Label to go to on fatal error.
+ */
+#define LY_VAL_ERR_GOTO(r, err_cmd, val_opts, label) \
+        if (r) { \
+            err_cmd; \
+            if ((r != LY_EVALID) || !(val_opts & LYD_VALIDATE_MULTI_ERROR)) { \
+                goto label; \
+            } \
+        }
+
+LY_ERR
+lyd_val_diff_add(const struct lyd_node *node, enum lyd_diff_op op, struct lyd_node **diff)
+{
+    LY_ERR ret = LY_SUCCESS;
+    struct lyd_node *new_diff = NULL;
+    const struct lyd_node *prev_inst;
+    char *key = NULL, *value = NULL, *position = NULL;
+    size_t buflen = 0, bufused = 0;
+    uint32_t pos;
+
+    assert((op == LYD_DIFF_OP_DELETE) || (op == LYD_DIFF_OP_CREATE));
+
+    if ((op == LYD_DIFF_OP_CREATE) && lysc_is_userordered(node->schema)) {
+        if (lysc_is_dup_inst_list(node->schema)) {
+            pos = lyd_list_pos(node);
+
+            /* generate position meta */
+            if (pos > 1) {
+                if (asprintf(&position, "%" PRIu32, pos - 1) == -1) {
+                    LOGMEM(LYD_CTX(node));
+                    ret = LY_EMEM;
+                    goto cleanup;
+                }
+            } else {
+                position = strdup("");
+                LY_CHECK_ERR_GOTO(!position, LOGMEM(LYD_CTX(node)); ret = LY_EMEM, cleanup);
+            }
+        } else {
+            if (node->prev->next && (node->prev->schema == node->schema)) {
+                prev_inst = node->prev;
+            } else {
+                /* first instance */
+                prev_inst = NULL;
+            }
+
+            if (node->schema->nodetype == LYS_LIST) {
+                /* generate key meta */
+                if (prev_inst) {
+                    LY_CHECK_GOTO(ret = lyd_path_list_predicate(prev_inst, &key, &buflen, &bufused, 0), cleanup);
+                } else {
+                    key = strdup("");
+                    LY_CHECK_ERR_GOTO(!key, LOGMEM(LYD_CTX(node)); ret = LY_EMEM, cleanup);
+                }
+            } else {
+                /* generate value meta */
+                if (prev_inst) {
+                    value = strdup(lyd_get_value(prev_inst));
+                    LY_CHECK_ERR_GOTO(!value, LOGMEM(LYD_CTX(node)); ret = LY_EMEM, cleanup);
+                } else {
+                    value = strdup("");
+                    LY_CHECK_ERR_GOTO(!value, LOGMEM(LYD_CTX(node)); ret = LY_EMEM, cleanup);
+                }
+            }
+        }
+    }
+
+    /* create new diff tree */
+    LY_CHECK_GOTO(ret = lyd_diff_add(node, op, NULL, NULL, key, value, position, NULL, NULL, &new_diff), cleanup);
+
+    /* merge into existing diff */
+    ret = lyd_diff_merge_all(diff, new_diff, 0);
+
+cleanup:
+    lyd_free_tree(new_diff);
+    free(key);
+    free(value);
+    free(position);
+    return ret;
+}
+
+/**
+ * @brief Evaluate all relevant "when" conditions of a node.
+ *
+ * @param[in] tree Data tree.
+ * @param[in] node Node whose relevant when conditions will be evaluated.
+ * @param[in] schema Schema node of @p node. It may not be possible to use directly if @p node is opaque.
+ * @param[in] xpath_options Additional XPath options to use.
+ * @param[out] disabled First when that evaluated false, if any.
+ * @return LY_SUCCESS on success.
+ * @return LY_EINCOMPLETE if a referenced node does not have its when evaluated.
+ * @return LY_ERR value on error.
+ */
+static LY_ERR
+lyd_validate_node_when(const struct lyd_node *tree, const struct lyd_node *node, const struct lysc_node *schema,
+        uint32_t xpath_options, const struct lysc_when **disabled)
+{
+    LY_ERR r;
+    const struct lyd_node *ctx_node;
+    struct lyxp_set xp_set;
+    LY_ARRAY_COUNT_TYPE u;
+
+    assert(!node->schema || (node->schema == schema));
+
+    *disabled = NULL;
+
+    do {
+        const struct lysc_when *when;
+        struct lysc_when **when_list = lysc_node_when(schema);
+
+        LY_ARRAY_FOR(when_list, u) {
+            when = when_list[u];
+
+            /* get context node */
+            if (when->context == schema) {
+                ctx_node = node;
+            } else {
+                assert((!when->context && !node->parent) || (when->context == node->parent->schema));
+                ctx_node = lyd_parent(node);
+            }
+
+            /* evaluate when */
+            memset(&xp_set, 0, sizeof xp_set);
+            r = lyxp_eval(LYD_CTX(node), when->cond, schema->module, LY_VALUE_SCHEMA_RESOLVED, when->prefixes,
+                    ctx_node, ctx_node, tree, NULL, &xp_set, LYXP_SCHEMA | xpath_options);
+            lyxp_set_cast(&xp_set, LYXP_SET_BOOLEAN);
+
+            /* return error or LY_EINCOMPLETE for dependant unresolved when */
+            LY_CHECK_RET(r);
+
+            if (!xp_set.val.bln) {
+                /* false when */
+                *disabled = when;
+                return LY_SUCCESS;
+            }
+        }
+
+        schema = schema->parent;
+    } while (schema && (schema->nodetype & (LYS_CASE | LYS_CHOICE)));
+
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Properly delete a node as part of auto-delete validation tasks.
+ *
+ * @param[in,out] first First sibling, is updated if needed.
+ * @param[in] del Node instance to delete.
+ * @param[in] mod Module of the siblings, NULL for nested siblings.
+ * @param[in] np_cont_diff Whether to put NP container into diff or only its children.
+ * @param[in,out] node Optional current iteration node, update it if it is deleted.
+ * @param[in,out] node_when Optional set with nodes with "when" conditions, may be removed from.
+ * @param[in,out] diff Validation diff.
+ * @return 1 if @p node auto-deleted and updated to its next sibling.
+ * @return 0 if @p node was not auto-deleted.
+ */
+static ly_bool
+lyd_validate_autodel_node_del(struct lyd_node **first, struct lyd_node *del, const struct lys_module *mod,
+        int np_cont_diff, struct lyd_node **node, struct ly_set *node_types, struct lyd_node **diff)
+{
+    struct lyd_node *iter;
+    ly_bool node_autodel = 0;
+    uint32_t idx;
+
+    /* update pointers */
+    lyd_del_move_root(first, del, mod);
+    if (node && (del == *node)) {
+        *node = (*node)->next;
+        node_autodel = 1;
+    }
+
+    if (diff) {
+        /* add into diff */
+        if (!np_cont_diff && (del->schema->nodetype == LYS_CONTAINER) && !(del->schema->flags & LYS_PRESENCE)) {
+            /* we do not want to track NP container changes, but remember any removed children */
+            LY_LIST_FOR(lyd_child(del), iter) {
+                lyd_val_diff_add(iter, LYD_DIFF_OP_DELETE, diff);
+            }
+        } else {
+            lyd_val_diff_add(del, LYD_DIFF_OP_DELETE, diff);
+        }
+    }
+
+    if (node_types && node_types->count) {
+        /* remove from node_types set */
+        LYD_TREE_DFS_BEGIN(del, iter) {
+            if (ly_set_contains(node_types, iter, &idx)) {
+                ly_set_rm_index(node_types, idx, NULL);
+            }
+            LYD_TREE_DFS_END(del, iter);
+        }
+    }
+
+    /* free */
+    lyd_free_tree(del);
+
+    return node_autodel;
+}
+
+/**
+ * @brief Evaluate when conditions of collected unres nodes.
+ *
+ * @param[in,out] tree Data tree, is updated if some nodes are autodeleted.
+ * @param[in] mod Module of the @p tree to take into consideration when deleting @p tree and moving it.
+ * If set, it is expected @p tree should point to the first node of @p mod. Otherwise it will simply be
+ * the first top-level sibling.
+ * @param[in] node_when Set with nodes with "when" conditions.
+ * @param[in] val_opts Validation options.
+ * @param[in] xpath_options Additional XPath options to use.
+ * @param[in,out] node_types Set with nodes with unresolved types, remove any with false "when" parents.
+ * @param[in,out] diff Validation diff.
+ * @return LY_SUCCESS on success.
+ * @return LY_ERR value on error.
+ */
+static LY_ERR
+lyd_validate_unres_when(struct lyd_node **tree, const struct lys_module *mod, struct ly_set *node_when, uint32_t val_opts,
+        uint32_t xpath_options, struct ly_set *node_types, struct lyd_node **diff)
+{
+    LY_ERR rc = LY_SUCCESS, r;
+    uint32_t i;
+    const struct lysc_when *disabled;
+    struct lyd_node *node = NULL;
+
+    if (!node_when->count) {
+        return LY_SUCCESS;
+    }
+
+    i = node_when->count;
+    do {
+        --i;
+        node = node_when->dnodes[i];
+        LOG_LOCSET(node->schema, node);
+
+        /* evaluate all when expressions that affect this node's existence */
+        r = lyd_validate_node_when(*tree, node, node->schema, xpath_options, &disabled);
+        if (!r) {
+            if (disabled) {
+                /* when false */
+                if (node->flags & LYD_WHEN_TRUE) {
+                    /* autodelete */
+                    lyd_validate_autodel_node_del(tree, node, mod, 1, NULL, node_types, diff);
+                } else if (val_opts & LYD_VALIDATE_OPERATIONAL) {
+                    /* only a warning */
+                    LOGWRN(LYD_CTX(node), "When condition \"%s\" not satisfied.", disabled->cond->expr);
+                } else {
+                    /* invalid data */
+                    LOGVAL(LYD_CTX(node), LY_VCODE_NOWHEN, disabled->cond->expr);
+                    r = LY_EVALID;
+                    LY_VAL_ERR_GOTO(r, rc = r, val_opts, error);
+                }
+            } else {
+                /* when true */
+                node->flags |= LYD_WHEN_TRUE;
+            }
+
+            /* remove this node from the set keeping the order, its when was resolved */
+            ly_set_rm_index_ordered(node_when, i, NULL);
+        } else if (r != LY_EINCOMPLETE) {
+            /* error */
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, error);
+        }
+
+        LOG_LOCBACK(1, 1);
+    } while (i);
+
+    return rc;
+
+error:
+    LOG_LOCBACK(1, 1);
+    return rc;
+}
+
+LY_ERR
+lyd_validate_unres(struct lyd_node **tree, const struct lys_module *mod, enum lyd_type data_type, struct ly_set *node_when,
+        uint32_t when_xp_opts, struct ly_set *node_types, struct ly_set *meta_types, struct ly_set *ext_node,
+        struct ly_set *ext_val, uint32_t val_opts, struct lyd_node **diff)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    uint32_t i;
+
+    if (ext_val && ext_val->count) {
+        /* first validate parsed extension data */
+        i = ext_val->count;
+        do {
+            --i;
+
+            struct lyd_ctx_ext_val *ext_v = ext_val->objs[i];
+
+            /* validate extension data */
+            r = ext_v->ext->def->plugin->validate(ext_v->ext, ext_v->sibling, *tree, data_type, val_opts, diff);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* remove this item from the set */
+            ly_set_rm_index(ext_val, i, free);
+        } while (i);
+    }
+
+    if (ext_node && ext_node->count) {
+        /* validate data nodes with extension instances */
+        i = ext_node->count;
+        do {
+            --i;
+
+            struct lyd_ctx_ext_node *ext_n = ext_node->objs[i];
+
+            /* validate the node */
+            r = ext_n->ext->def->plugin->node(ext_n->ext, ext_n->node, val_opts);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* remove this item from the set */
+            ly_set_rm_index(ext_node, i, free);
+        } while (i);
+    }
+
+    if (node_when) {
+        /* evaluate all when conditions */
+        uint32_t prev_count;
+
+        do {
+            prev_count = node_when->count;
+            r = lyd_validate_unres_when(tree, mod, node_when, val_opts, when_xp_opts, node_types, diff);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* there must have been some when conditions resolved */
+        } while (prev_count > node_when->count);
+
+        /* there could have been no cyclic when dependencies, checked during compilation */
+        assert(!node_when->count || ((rc == LY_EVALID) && (val_opts & LYD_VALIDATE_MULTI_ERROR)));
+    }
+
+    if (node_types && node_types->count) {
+        /* finish incompletely validated terminal values (traverse from the end for efficient set removal) */
+        i = node_types->count;
+        do {
+            --i;
+
+            struct lyd_node_term *node = node_types->objs[i];
+            struct lysc_type *type = ((struct lysc_node_leaf *)node->schema)->type;
+
+            /* resolve the value of the node */
+            LOG_LOCSET(NULL, &node->node);
+            r = lyd_value_validate_incomplete(LYD_CTX(node), type, &node->value, &node->node, *tree);
+            LOG_LOCBACK(0, 1);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* remove this node from the set */
+            ly_set_rm_index(node_types, i, NULL);
+        } while (i);
+    }
+
+    if (meta_types && meta_types->count) {
+        /* ... and metadata values */
+        i = meta_types->count;
+        do {
+            --i;
+
+            struct lyd_meta *meta = meta_types->objs[i];
+            struct lysc_type *type;
+
+            /* validate and store the value of the metadata */
+            lyplg_ext_get_storage(meta->annotation, LY_STMT_TYPE, sizeof type, (const void **)&type);
+            r = lyd_value_validate_incomplete(LYD_CTX(meta->parent), type, &meta->value, meta->parent, *tree);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* remove this attr from the set */
+            ly_set_rm_index(meta_types, i, NULL);
+        } while (i);
+    }
+
+cleanup:
+    return rc;
+}
+
+/**
+ * @brief Validate instance duplication.
+ *
+ * @param[in] first First sibling to search in.
+ * @param[in] node Data node instance to check.
+ * @param[in] val_opts Validation options.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_duplicates(const struct lyd_node *first, const struct lyd_node *node, uint32_t val_opts)
+{
+    struct lyd_node **match_p, *match;
+    ly_bool fail = 0;
+
+    assert(node->flags & LYD_NEW);
+
+    /* key-less list or non-configuration leaf-list */
+    if (lysc_is_dup_inst_list(node->schema)) {
+        /* duplicate instances allowed */
+        return LY_SUCCESS;
+    }
+
+    /* find exactly the same next instance using hashes if possible */
+    if (node->parent && node->parent->children_ht) {
+        lyd_find_sibling_first(first, node, &match);
+        assert(match);
+
+        if (match != node) {
+            fail = 1;
+        } else if (!lyht_find_next(node->parent->children_ht, &node, node->hash, (void **)&match_p)) {
+            fail = 1;
+        }
+    } else {
+        for ( ; first; first = first->next) {
+            if (first == node) {
+                continue;
+            }
+
+            if (node->schema->nodetype & (LYD_NODE_ANY | LYS_LEAF)) {
+                if (first->schema == node->schema) {
+                    fail = 1;
+                    break;
+                }
+            } else if (!lyd_compare_single(first, node, 0)) {
+                fail = 1;
+                break;
+            }
+        }
+    }
+
+    if (fail) {
+        if ((node->schema->nodetype & (LYS_LIST | LYS_LEAFLIST)) && (val_opts & LYD_VALIDATE_OPERATIONAL)) {
+            /* only a warning */
+            LOG_LOCSET(NULL, node);
+            LOGWRN(node->schema->module->ctx, "Duplicate instance of \"%s\".", node->schema->name);
+            LOG_LOCBACK(0, 1);
+        } else {
+            LOG_LOCSET(NULL, node);
+            LOGVAL(node->schema->module->ctx, LY_VCODE_DUP, node->schema->name);
+            LOG_LOCBACK(0, 1);
+            return LY_EVALID;
+        }
+    }
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Validate multiple case data existence with possible autodelete.
+ *
+ * @param[in,out] first First sibling to search in, is updated if needed.
+ * @param[in] mod Module of the siblings, NULL for nested siblings.
+ * @param[in] choic Choice node whose cases to check.
+ * @param[in,out] diff Validation diff.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_cases(struct lyd_node **first, const struct lys_module *mod, const struct lysc_node_choice *choic,
+        struct lyd_node **diff)
+{
+    const struct lysc_node *scase, *iter, *old_case = NULL, *new_case = NULL;
+    struct lyd_node *match, *to_del;
+    ly_bool found;
+
+    LOG_LOCSET(&choic->node, NULL);
+
+    LY_LIST_FOR((struct lysc_node *)choic->cases, scase) {
+        found = 0;
+        iter = NULL;
+        match = NULL;
+        while ((match = lys_getnext_data(match, *first, &iter, scase, NULL))) {
+            if (match->flags & LYD_NEW) {
+                /* a new case data found, nothing more to look for */
+                found = 2;
+                break;
+            } else {
+                /* and old case data found */
+                if (found == 0) {
+                    found = 1;
+                }
+            }
+        }
+
+        if (found == 1) {
+            /* there should not be 2 old cases */
+            if (old_case) {
+                /* old data from 2 cases */
+                LOGVAL(choic->module->ctx, LY_VCODE_DUPCASE, old_case->name, scase->name);
+                LOG_LOCBACK(1, 0);
+                return LY_EVALID;
+            }
+
+            /* remember an old existing case */
+            old_case = scase;
+        } else if (found == 2) {
+            if (new_case) {
+                /* new data from 2 cases */
+                LOGVAL(choic->module->ctx, LY_VCODE_DUPCASE, new_case->name, scase->name);
+                LOG_LOCBACK(1, 0);
+                return LY_EVALID;
+            }
+
+            /* remember a new existing case */
+            new_case = scase;
+        }
+    }
+
+    LOG_LOCBACK(1, 0);
+
+    if (old_case && new_case) {
+        /* auto-delete old case */
+        iter = NULL;
+        match = NULL;
+        to_del = NULL;
+        while ((match = lys_getnext_data(match, *first, &iter, old_case, NULL))) {
+            lyd_del_move_root(first, to_del, mod);
+
+            /* free previous node */
+            lyd_free_tree(to_del);
+            if (diff) {
+                /* add into diff */
+                LY_CHECK_RET(lyd_val_diff_add(match, LYD_DIFF_OP_DELETE, diff));
+            }
+            to_del = match;
+        }
+        lyd_del_move_root(first, to_del, mod);
+        lyd_free_tree(to_del);
+    }
+
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Check whether a schema node can have some default values (true for NP containers as well).
+ *
+ * @param[in] schema Schema node to check.
+ * @return non-zero if yes,
+ * @return 0 otherwise.
+ */
+static int
+lyd_val_has_default(const struct lysc_node *schema)
+{
+    switch (schema->nodetype) {
+    case LYS_LEAF:
+        if (((struct lysc_node_leaf *)schema)->dflt) {
+            return 1;
+        }
+        break;
+    case LYS_LEAFLIST:
+        if (((struct lysc_node_leaflist *)schema)->dflts) {
+            return 1;
+        }
+        break;
+    case LYS_CONTAINER:
+        if (!(schema->flags & LYS_PRESENCE)) {
+            return 1;
+        }
+        break;
+    default:
+        break;
+    }
+
+    return 0;
+}
+
+/**
+ * @brief Auto-delete leaf-list default instances to prevent validation errors.
+ *
+ * @param[in,out] first First sibling to search in, is updated if needed.
+ * @param[in,out] node New data node instance to check, is updated if auto-deleted.
+ * @param[in] mod Module of the siblings, NULL for nested siblings.
+ * @param[in,out] diff Validation diff.
+ * @return 1 if @p node auto-deleted and updated to its next sibling.
+ * @return 0 if @p node was not auto-deleted.
+ */
+static ly_bool
+lyd_validate_autodel_leaflist_dflt(struct lyd_node **first, struct lyd_node **node, const struct lys_module *mod,
+        struct lyd_node **diff)
+{
+    const struct lysc_node *schema;
+    struct lyd_node *iter, *next;
+    ly_bool found = 0, node_autodel = 0;
+
+    assert((*node)->flags & LYD_NEW);
+
+    schema = (*node)->schema;
+    assert(schema->nodetype == LYS_LEAFLIST);
+
+    /* check whether there is any explicit instance */
+    LYD_LIST_FOR_INST(*first, schema, iter) {
+        if (!(iter->flags & LYD_DEFAULT)) {
+            found = 1;
+            break;
+        }
+    }
+    if (!found) {
+        /* no explicit instance, keep defaults as they are */
+        return 0;
+    }
+
+    LYD_LIST_FOR_INST_SAFE(*first, schema, next, iter) {
+        if (iter->flags & LYD_DEFAULT) {
+            /* default instance found, remove it */
+            if (lyd_validate_autodel_node_del(first, iter, mod, 0, node, NULL, diff)) {
+                node_autodel = 1;
+            }
+        }
+    }
+
+    return node_autodel;
+}
+
+/**
+ * @brief Auto-delete container or leaf default instances to prevent validation errors.
+ *
+ * @param[in,out] first First sibling to search in, is updated if needed.
+ * @param[in,out] node New data node instance to check, is updated if auto-deleted.
+ * @param[in] mod Module of the siblings, NULL for nested siblings.
+ * @param[in,out] diff Validation diff.
+ * @return 1 if @p node auto-deleted and updated to its next sibling.
+ * @return 0 if @p node was not auto-deleted.
+ */
+static ly_bool
+lyd_validate_autodel_cont_leaf_dflt(struct lyd_node **first, struct lyd_node **node, const struct lys_module *mod,
+        struct lyd_node **diff)
+{
+    const struct lysc_node *schema;
+    struct lyd_node *iter, *next;
+    ly_bool found = 0, node_autodel = 0;
+
+    assert((*node)->flags & LYD_NEW);
+
+    schema = (*node)->schema;
+    assert(schema->nodetype & (LYS_LEAF | LYS_CONTAINER));
+
+    /* check whether there is any explicit instance */
+    LYD_LIST_FOR_INST(*first, schema, iter) {
+        if (!(iter->flags & LYD_DEFAULT)) {
+            found = 1;
+            break;
+        }
+    }
+
+    if (found) {
+        /* remove all default instances */
+        LYD_LIST_FOR_INST_SAFE(*first, schema, next, iter) {
+            if (iter->flags & LYD_DEFAULT) {
+                /* default instance, remove it */
+                if (lyd_validate_autodel_node_del(first, iter, mod, 0, node, NULL, diff)) {
+                    node_autodel = 1;
+                }
+            }
+        }
+    } else {
+        /* remove a single old default instance, if any */
+        LYD_LIST_FOR_INST(*first, schema, iter) {
+            if ((iter->flags & LYD_DEFAULT) && !(iter->flags & LYD_NEW)) {
+                /* old default instance, remove it */
+                if (lyd_validate_autodel_node_del(first, iter, mod, 0, node, NULL, diff)) {
+                    node_autodel = 1;
+                }
+                break;
+            }
+        }
+    }
+
+    return node_autodel;
+}
+
+/**
+ * @brief Auto-delete leftover default nodes of deleted cases (that have no existing explicit data).
+ *
+ * @param[in,out] first First sibling to search in, is updated if needed.
+ * @param[in,out] node Default data node instance to check.
+ * @param[in] mod Module of the siblings, NULL for nested siblings.
+ * @param[in,out] diff Validation diff.
+ * @return 1 if @p node auto-deleted and updated to its next sibling.
+ * @return 0 if @p node was not auto-deleted.
+ */
+static ly_bool
+lyd_validate_autodel_case_dflt(struct lyd_node **first, struct lyd_node **node, const struct lys_module *mod,
+        struct lyd_node **diff)
+{
+    const struct lysc_node *schema;
+    struct lysc_node_choice *choic;
+    struct lyd_node *iter = NULL;
+    const struct lysc_node *slast = NULL;
+    ly_bool node_autodel = 0;
+
+    assert((*node)->flags & LYD_DEFAULT);
+
+    schema = (*node)->schema;
+
+    if (!schema->parent || (schema->parent->nodetype != LYS_CASE)) {
+        /* the default node is not a descendant of a case */
+        return 0;
+    }
+
+    choic = (struct lysc_node_choice *)schema->parent->parent;
+    assert(choic->nodetype == LYS_CHOICE);
+
+    if (choic->dflt && (choic->dflt == (struct lysc_node_case *)schema->parent)) {
+        /* data of a default case, keep them */
+        return 0;
+    }
+
+    /* try to find an explicit node of the case */
+    while ((iter = lys_getnext_data(iter, *first, &slast, schema->parent, NULL))) {
+        if (!(iter->flags & LYD_DEFAULT)) {
+            break;
+        }
+    }
+
+    if (!iter) {
+        /* there are only default nodes of the case meaning it does not exist and neither should any default nodes
+         * of the case, remove this one default node */
+        if (lyd_validate_autodel_node_del(first, *node, mod, 0, node, NULL, diff)) {
+            node_autodel = 1;
+        }
+    }
+
+    return node_autodel;
+}
+
+/**
+ * @brief Validate new siblings in choices, recursively for nested choices.
+ *
+ * @param[in,out] first First sibling.
+ * @param[in] sparent Schema parent of the siblings, NULL for top-level siblings.
+ * @param[in] mod Module of the siblings, NULL for nested siblings.
+ * @param[in] val_opts Validation options.
+ * @param[in,out] diff Validation diff.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_choice_r(struct lyd_node **first, const struct lysc_node *sparent, const struct lys_module *mod,
+        uint32_t val_opts, struct lyd_node **diff)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    const struct lysc_node *snode = NULL;
+
+    while (*first && (snode = lys_getnext(snode, sparent, mod ? mod->compiled : NULL, LYS_GETNEXT_WITHCHOICE))) {
+        /* check case duplicites */
+        if (snode->nodetype == LYS_CHOICE) {
+            r = lyd_validate_cases(first, mod, (struct lysc_node_choice *)snode, diff);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* check for nested choice */
+            r = lyd_validate_choice_r(first, snode, mod, val_opts, diff);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+        }
+    }
+
+cleanup:
+    return rc;
+}
+
+LY_ERR
+lyd_validate_new(struct lyd_node **first, const struct lysc_node *sparent, const struct lys_module *mod,
+        uint32_t val_opts, struct lyd_node **diff)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    struct lyd_node *node;
+    const struct lysc_node *last_dflt_schema = NULL;
+
+    assert(first && (sparent || mod));
+
+    /* validate choices */
+    r = lyd_validate_choice_r(first, sparent, mod, val_opts, diff);
+    LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+    node = *first;
+    while (node) {
+        if (!node->schema || (mod && (lyd_owner_module(node) != mod))) {
+            /* opaque node or all top-level data from this module checked */
+            break;
+        }
+
+        if (!(node->flags & (LYD_NEW | LYD_DEFAULT))) {
+            /* check only new and default nodes */
+            node = node->next;
+            continue;
+        }
+
+        if (lyd_val_has_default(node->schema) && (node->schema != last_dflt_schema) && (node->flags & LYD_NEW)) {
+            /* remove old default(s) of the new node if an explicit instance exists */
+            last_dflt_schema = node->schema;
+            if (node->schema->nodetype == LYS_LEAFLIST) {
+                if (lyd_validate_autodel_leaflist_dflt(first, &node, mod, diff)) {
+                    continue;
+                }
+            } else {
+                if (lyd_validate_autodel_cont_leaf_dflt(first, &node, mod, diff)) {
+                    continue;
+                }
+            }
+        }
+
+        if (node->flags & LYD_NEW) {
+            /* then check new node instance duplicities */
+            r = lyd_validate_duplicates(*first, node, val_opts);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* this node is valid */
+            node->flags &= ~LYD_NEW;
+        }
+
+        if (node->flags & LYD_DEFAULT) {
+            /* remove leftover default nodes from a no-longer existing case */
+            if (lyd_validate_autodel_case_dflt(first, &node, mod, diff)) {
+                continue;
+            }
+        }
+
+        /* next iter */
+        node = node->next;
+    }
+
+cleanup:
+    return rc;
+}
+
+/**
+ * @brief Evaluate any "when" conditions of a non-existent data node with existing parent.
+ *
+ * @param[in] first First data sibling of the non-existing node.
+ * @param[in] parent Data parent of the non-existing node.
+ * @param[in] snode Schema node of the non-existing node.
+ * @param[out] disabled First when that evaluated false, if any.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_dummy_when(const struct lyd_node *first, const struct lyd_node *parent, const struct lysc_node *snode,
+        const struct lysc_when **disabled)
+{
+    LY_ERR rc = LY_SUCCESS;
+    struct lyd_node *tree, *dummy = NULL;
+    uint32_t xp_opts;
+
+    /* find root */
+    if (parent) {
+        tree = (struct lyd_node *)parent;
+        while (tree->parent) {
+            tree = lyd_parent(tree);
+        }
+        tree = lyd_first_sibling(tree);
+    } else {
+        /* is the first sibling from the same module, but may not be the actual first */
+        tree = lyd_first_sibling(first);
+    }
+
+    /* create dummy opaque node */
+    rc = lyd_new_opaq((struct lyd_node *)parent, snode->module->ctx, snode->name, NULL, NULL, snode->module->name, &dummy);
+    LY_CHECK_GOTO(rc, cleanup);
+
+    /* connect it if needed */
+    if (!parent) {
+        if (first) {
+            lyd_insert_sibling((struct lyd_node *)first, dummy, &tree);
+        } else {
+            assert(!tree);
+            tree = dummy;
+        }
+    }
+
+    /* explicitly specified accesible tree */
+    if (snode->flags & LYS_CONFIG_W) {
+        xp_opts = LYXP_ACCESS_TREE_CONFIG;
+    } else {
+        xp_opts = LYXP_ACCESS_TREE_ALL;
+    }
+
+    /* evaluate all when */
+    rc = lyd_validate_node_when(tree, dummy, snode, xp_opts, disabled);
+    if (rc == LY_EINCOMPLETE) {
+        /* all other when must be resolved by now */
+        LOGINT(snode->module->ctx);
+        rc = LY_EINT;
+        goto cleanup;
+    } else if (rc) {
+        /* error */
+        goto cleanup;
+    }
+
+cleanup:
+    lyd_free_tree(dummy);
+    return rc;
+}
+
+/**
+ * @brief Validate mandatory node existence.
+ *
+ * @param[in] first First sibling to search in.
+ * @param[in] parent Data parent.
+ * @param[in] snode Schema node to validate.
+ * @param[in] val_opts Validation options.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_mandatory(const struct lyd_node *first, const struct lyd_node *parent, const struct lysc_node *snode,
+        uint32_t val_opts)
+{
+    const struct lysc_when *disabled;
+
+    if (snode->nodetype == LYS_CHOICE) {
+        /* some data of a choice case exist */
+        if (lys_getnext_data(NULL, first, NULL, snode, NULL)) {
+            return LY_SUCCESS;
+        }
+    } else {
+        assert(snode->nodetype & (LYS_LEAF | LYS_CONTAINER | LYD_NODE_ANY));
+
+        if (!lyd_find_sibling_val(first, snode, NULL, 0, NULL)) {
+            /* data instance found */
+            return LY_SUCCESS;
+        }
+    }
+
+    disabled = NULL;
+    if (lysc_has_when(snode)) {
+        /* if there are any when conditions, they must be true for a validation error */
+        LY_CHECK_RET(lyd_validate_dummy_when(first, parent, snode, &disabled));
+    }
+
+    if (!disabled) {
+        if (val_opts & LYD_VALIDATE_OPERATIONAL) {
+            /* only a warning */
+            LOG_LOCSET(parent ? NULL : snode, parent);
+            if (snode->nodetype == LYS_CHOICE) {
+                LOGWRN(snode->module->ctx, "Mandatory choice \"%s\" data do not exist.", snode->name);
+            } else {
+                LOGWRN(snode->module->ctx, "Mandatory node \"%s\" instance does not exist.", snode->name);
+            }
+            LOG_LOCBACK(parent ? 0 : 1, parent ? 1 : 0);
+        } else {
+            /* node instance not found */
+            LOG_LOCSET(parent ? NULL : snode, parent);
+            if (snode->nodetype == LYS_CHOICE) {
+                LOGVAL_APPTAG(snode->module->ctx, "missing-choice", LY_VCODE_NOMAND_CHOIC, snode->name);
+            } else {
+                LOGVAL(snode->module->ctx, LY_VCODE_NOMAND, snode->name);
+            }
+            LOG_LOCBACK(parent ? 0 : 1, parent ? 1 : 0);
+            return LY_EVALID;
+        }
+    }
+
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Validate min/max-elements constraints, if any.
+ *
+ * @param[in] first First sibling to search in.
+ * @param[in] parent Data parent.
+ * @param[in] snode Schema node to validate.
+ * @param[in] min Minimum number of elements, 0 for no restriction.
+ * @param[in] max Max number of elements, 0 for no restriction.
+ * @param[in] val_opts Validation options.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_minmax(const struct lyd_node *first, const struct lyd_node *parent, const struct lysc_node *snode,
+        uint32_t min, uint32_t max, uint32_t val_opts)
+{
+    uint32_t count = 0;
+    struct lyd_node *iter;
+    const struct lysc_when *disabled;
+
+    assert(min || max);
+
+    LYD_LIST_FOR_INST(first, snode, iter) {
+        ++count;
+
+        if (min && (count == min)) {
+            /* satisfied */
+            min = 0;
+            if (!max) {
+                /* nothing more to check */
+                break;
+            }
+        }
+        if (max && (count > max)) {
+            /* not satisifed */
+            break;
+        }
+    }
+
+    if (min) {
+        assert(count < min);
+
+        disabled = NULL;
+        if (lysc_has_when(snode)) {
+            /* if there are any when conditions, they must be true for a validation error */
+            LY_CHECK_RET(lyd_validate_dummy_when(first, parent, snode, &disabled));
+        }
+
+        if (disabled) {
+            /* satisfied */
+            min = 0;
+        }
+    }
+    if (max && (count <= max)) {
+        /* satisfied */
+        max = 0;
+    }
+
+    if (min) {
+        if (val_opts & LYD_VALIDATE_OPERATIONAL) {
+            /* only a warning */
+            LOG_LOCSET(snode, NULL);
+            LOGWRN(snode->module->ctx, "Too few \"%s\" instances.", snode->name);
+            LOG_LOCBACK(1, 0);
+        } else {
+            LOG_LOCSET(snode, NULL);
+            LOGVAL_APPTAG(snode->module->ctx, "too-few-elements", LY_VCODE_NOMIN, snode->name);
+            LOG_LOCBACK(1, 0);
+            return LY_EVALID;
+        }
+    } else if (max) {
+        if (val_opts & LYD_VALIDATE_OPERATIONAL) {
+            /* only a warning */
+            LOG_LOCSET(NULL, iter);
+            LOGWRN(snode->module->ctx, "Too many \"%s\" instances.", snode->name);
+            LOG_LOCBACK(0, 1);
+        } else {
+            LOG_LOCSET(NULL, iter);
+            LOGVAL_APPTAG(snode->module->ctx, "too-many-elements", LY_VCODE_NOMAX, snode->name);
+            LOG_LOCBACK(0, 1);
+            return LY_EVALID;
+        }
+    }
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Find node referenced by a list unique statement.
+ *
+ * @param[in] uniq_leaf Unique leaf to find.
+ * @param[in] list List instance to use for the search.
+ * @return Found leaf,
+ * @return NULL if no leaf found.
+ */
+static struct lyd_node *
+lyd_val_uniq_find_leaf(const struct lysc_node_leaf *uniq_leaf, const struct lyd_node *list)
+{
+    struct lyd_node *node;
+    const struct lysc_node *iter;
+    size_t depth = 0, i;
+
+    /* get leaf depth */
+    for (iter = &uniq_leaf->node; iter && (iter != list->schema); iter = lysc_data_parent(iter)) {
+        ++depth;
+    }
+
+    node = (struct lyd_node *)list;
+    while (node && depth) {
+        /* find schema node with this depth */
+        for (i = depth - 1, iter = &uniq_leaf->node; i; iter = lysc_data_parent(iter)) {
+            --i;
+        }
+
+        /* find iter instance in children */
+        assert(iter->nodetype & (LYS_CONTAINER | LYS_LEAF));
+        lyd_find_sibling_val(lyd_child(node), iter, NULL, 0, &node);
+        --depth;
+    }
+
+    return node;
+}
+
+/**
+ * @brief Unique list validation callback argument.
+ */
+struct lyd_val_uniq_arg {
+    LY_ARRAY_COUNT_TYPE action; /**< Action to perform - 0 to compare all uniques, n to compare only n-th unique. */
+    uint32_t val_opts;          /**< Validation options. */
+};
+
+/**
+ * @brief Callback for comparing 2 list unique leaf values.
+ *
+ * Implementation of ::lyht_value_equal_cb.
+ */
+static ly_bool
+lyd_val_uniq_list_equal(void *val1_p, void *val2_p, ly_bool UNUSED(mod), void *cb_data)
+{
+    struct ly_ctx *ctx;
+    struct lysc_node_list *slist;
+    struct lyd_node *diter, *first, *second;
+    struct lyd_value *val1, *val2;
+    char *path1, *path2, *uniq_str, *ptr;
+    LY_ARRAY_COUNT_TYPE u, v;
+    struct lyd_val_uniq_arg *arg = cb_data;
+    const uint32_t uniq_err_msg_size = 1024;
+
+    assert(val1_p && val2_p);
+
+    first = *((struct lyd_node **)val1_p);
+    second = *((struct lyd_node **)val2_p);
+
+    assert(first && (first->schema->nodetype == LYS_LIST));
+    assert(second && (second->schema == first->schema));
+
+    ctx = first->schema->module->ctx;
+
+    slist = (struct lysc_node_list *)first->schema;
+
+    /* compare unique leaves */
+    if (arg->action > 0) {
+        u = arg->action - 1;
+        if (u < LY_ARRAY_COUNT(slist->uniques)) {
+            goto uniquecheck;
+        }
+    }
+    LY_ARRAY_FOR(slist->uniques, u) {
+uniquecheck:
+        LY_ARRAY_FOR(slist->uniques[u], v) {
+            /* first */
+            diter = lyd_val_uniq_find_leaf(slist->uniques[u][v], first);
+            if (diter) {
+                val1 = &((struct lyd_node_term *)diter)->value;
+            } else {
+                /* use default value */
+                val1 = slist->uniques[u][v]->dflt;
+            }
+
+            /* second */
+            diter = lyd_val_uniq_find_leaf(slist->uniques[u][v], second);
+            if (diter) {
+                val2 = &((struct lyd_node_term *)diter)->value;
+            } else {
+                /* use default value */
+                val2 = slist->uniques[u][v]->dflt;
+            }
+
+            if (!val1 || !val2 || val1->realtype->plugin->compare(ctx, val1, val2)) {
+                /* values differ or either one is not set */
+                break;
+            }
+        }
+        if (v && (v == LY_ARRAY_COUNT(slist->uniques[u]))) {
+            /* all unique leaves are the same in this set, create this nice error */
+            path1 = lyd_path(first, LYD_PATH_STD, NULL, 0);
+            path2 = lyd_path(second, LYD_PATH_STD, NULL, 0);
+
+            /* use buffer to rebuild the unique string */
+            uniq_str = malloc(uniq_err_msg_size);
+            uniq_str[0] = '\0';
+            ptr = uniq_str;
+            LY_ARRAY_FOR(slist->uniques[u], v) {
+                if (v) {
+                    strcpy(ptr, " ");
+                    ++ptr;
+                }
+                ptr = lysc_path_until((struct lysc_node *)slist->uniques[u][v], &slist->node, LYSC_PATH_LOG,
+                        ptr, uniq_err_msg_size - (ptr - uniq_str));
+                if (!ptr) {
+                    /* path will be incomplete, whatever */
+                    break;
+                }
+
+                ptr += strlen(ptr);
+            }
+            LOG_LOCSET(NULL, second);
+            if (arg->val_opts & LYD_VALIDATE_OPERATIONAL) {
+                /* only a warning */
+                LOGWRN(ctx, "Unique data leaf(s) \"%s\" not satisfied in \"%s\" and \"%s\".", uniq_str, path1, path2);
+            } else {
+                LOGVAL_APPTAG(ctx, "data-not-unique", LY_VCODE_NOUNIQ, uniq_str, path1, path2);
+            }
+            LOG_LOCBACK(0, 1);
+
+            free(path1);
+            free(path2);
+            free(uniq_str);
+
+            if (!(arg->val_opts & LYD_VALIDATE_OPERATIONAL)) {
+                return 1;
+            }
+        }
+
+        if (arg->action > 0) {
+            /* done */
+            return 0;
+        }
+    }
+
+    return 0;
+}
+
+/**
+ * @brief Validate list unique leaves.
+ *
+ * @param[in] first First sibling to search in.
+ * @param[in] snode Schema node to validate.
+ * @param[in] uniques List unique arrays to validate.
+ * @param[in] val_opts Validation options.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_unique(const struct lyd_node *first, const struct lysc_node *snode, const struct lysc_node_leaf ***uniques,
+        uint32_t val_opts)
+{
+    const struct lyd_node *diter;
+    struct ly_set *set;
+    LY_ARRAY_COUNT_TYPE u, v, x = 0;
+    LY_ERR ret = LY_SUCCESS;
+    uint32_t hash, i;
+    size_t key_len;
+    ly_bool dyn;
+    const void *hash_key;
+    struct lyd_val_uniq_arg arg, *args = NULL;
+    struct ly_ht **uniqtables = NULL;
+    struct lyd_value *val;
+    struct ly_ctx *ctx = snode->module->ctx;
+
+    assert(uniques);
+
+    /* get all list instances */
+    LY_CHECK_RET(ly_set_new(&set));
+    LY_LIST_FOR(first, diter) {
+        if (diter->schema == snode) {
+            ret = ly_set_add(set, (void *)diter, 1, NULL);
+            LY_CHECK_GOTO(ret, cleanup);
+        }
+    }
+
+    if (set->count == 2) {
+        /* simple comparison */
+        arg.action = 0;
+        arg.val_opts = val_opts;
+        if (lyd_val_uniq_list_equal(&set->objs[0], &set->objs[1], 0, &arg)) {
+            /* instance duplication */
+            ret = LY_EVALID;
+            goto cleanup;
+        }
+    } else if (set->count > 2) {
+        /* use hashes for comparison */
+        uniqtables = malloc(LY_ARRAY_COUNT(uniques) * sizeof *uniqtables);
+        args = malloc(LY_ARRAY_COUNT(uniques) * sizeof *args);
+        LY_CHECK_ERR_GOTO(!uniqtables || !args, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+        x = LY_ARRAY_COUNT(uniques);
+        for (v = 0; v < x; v++) {
+            args[v].action = v + 1;
+            args[v].val_opts = val_opts;
+            uniqtables[v] = lyht_new(lyht_get_fixed_size(set->count), sizeof(struct lyd_node *),
+                    lyd_val_uniq_list_equal, &args[v], 0);
+            LY_CHECK_ERR_GOTO(!uniqtables[v], LOGMEM(ctx); ret = LY_EMEM, cleanup);
+        }
+
+        for (i = 0; i < set->count; i++) {
+            /* loop for unique - get the hash for the instances */
+            for (u = 0; u < x; u++) {
+                val = NULL;
+                for (v = hash = 0; v < LY_ARRAY_COUNT(uniques[u]); v++) {
+                    diter = lyd_val_uniq_find_leaf(uniques[u][v], set->objs[i]);
+                    if (diter) {
+                        val = &((struct lyd_node_term *)diter)->value;
+                    } else {
+                        /* use default value */
+                        val = uniques[u][v]->dflt;
+                    }
+                    if (!val) {
+                        /* unique item not present nor has default value */
+                        break;
+                    }
+
+                    /* get hash key */
+                    hash_key = val->realtype->plugin->print(NULL, val, LY_VALUE_LYB, NULL, &dyn, &key_len);
+                    hash = lyht_hash_multi(hash, hash_key, key_len);
+                    if (dyn) {
+                        free((void *)hash_key);
+                    }
+                }
+                if (!val) {
+                    /* skip this list instance since its unique set is incomplete */
+                    continue;
+                }
+
+                /* finish the hash value */
+                hash = lyht_hash_multi(hash, NULL, 0);
+
+                /* insert into the hashtable */
+                ret = lyht_insert(uniqtables[u], &set->objs[i], hash, NULL);
+                if (ret == LY_EEXIST) {
+                    /* instance duplication */
+                    ret = LY_EVALID;
+                }
+                LY_CHECK_GOTO(ret != LY_SUCCESS, cleanup);
+            }
+        }
+    }
+
+cleanup:
+    ly_set_free(set, NULL);
+    for (v = 0; v < x; v++) {
+        if (!uniqtables[v]) {
+            /* failed when allocating uniquetables[j], following j are not allocated */
+            break;
+        }
+        lyht_free(uniqtables[v], NULL);
+    }
+    free(uniqtables);
+    free(args);
+
+    return ret;
+}
+
+/**
+ * @brief Validate data siblings based on generic schema node restrictions, recursively for schema-only nodes.
+ *
+ * @param[in] first First sibling to search in.
+ * @param[in] parent Data parent.
+ * @param[in] sparent Schema parent of the nodes to check.
+ * @param[in] mod Module of the nodes to check.
+ * @param[in] val_opts Validation options, see @ref datavalidationoptions.
+ * @param[in] int_opts Internal parser options.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_siblings_schema_r(const struct lyd_node *first, const struct lyd_node *parent,
+        const struct lysc_node *sparent, const struct lysc_module *mod, uint32_t val_opts, uint32_t int_opts)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    const struct lysc_node *snode = NULL, *scase;
+    struct lysc_node_list *slist;
+    struct lysc_node_leaflist *sllist;
+    uint32_t getnext_opts;
+
+    getnext_opts = LYS_GETNEXT_WITHCHOICE | (int_opts & LYD_INTOPT_REPLY ? LYS_GETNEXT_OUTPUT : 0);
+
+    /* disabled nodes are skipped by lys_getnext */
+    while ((snode = lys_getnext(snode, sparent, mod, getnext_opts))) {
+        if ((val_opts & LYD_VALIDATE_NO_STATE) && (snode->flags & LYS_CONFIG_R)) {
+            continue;
+        }
+
+        /* check min-elements and max-elements */
+        if (snode->nodetype == LYS_LIST) {
+            slist = (struct lysc_node_list *)snode;
+            if (slist->min || slist->max) {
+                r = lyd_validate_minmax(first, parent, snode, slist->min, slist->max, val_opts);
+                LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+            }
+        } else if (snode->nodetype == LYS_LEAFLIST) {
+            sllist = (struct lysc_node_leaflist *)snode;
+            if (sllist->min || sllist->max) {
+                r = lyd_validate_minmax(first, parent, snode, sllist->min, sllist->max, val_opts);
+                LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+            }
+
+        } else if (snode->flags & LYS_MAND_TRUE) {
+            /* check generic mandatory existence */
+            r = lyd_validate_mandatory(first, parent, snode, val_opts);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+        }
+
+        /* check unique */
+        if (snode->nodetype == LYS_LIST) {
+            slist = (struct lysc_node_list *)snode;
+            if (slist->uniques) {
+                r = lyd_validate_unique(first, snode, (const struct lysc_node_leaf ***)slist->uniques, val_opts);
+                LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+            }
+        }
+
+        if (snode->nodetype == LYS_CHOICE) {
+            /* find the existing case, if any */
+            LY_LIST_FOR(lysc_node_child(snode), scase) {
+                if (lys_getnext_data(NULL, first, NULL, scase, NULL)) {
+                    /* validate only this case */
+                    r = lyd_validate_siblings_schema_r(first, parent, scase, mod, val_opts, int_opts);
+                    LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+                    break;
+                }
+            }
+        }
+    }
+
+cleanup:
+    return rc;
+}
+
+/**
+ * @brief Validate obsolete nodes, only warnings are printed.
+ *
+ * @param[in] node Node to check.
+ */
+static void
+lyd_validate_obsolete(const struct lyd_node *node)
+{
+    const struct lysc_node *snode;
+
+    snode = node->schema;
+    do {
+        if (snode->flags & LYS_STATUS_OBSLT) {
+            LOG_LOCSET(NULL, node);
+            LOGWRN(snode->module->ctx, "Obsolete schema node \"%s\" instantiated in data.", snode->name);
+            LOG_LOCBACK(0, 1);
+            break;
+        }
+
+        snode = snode->parent;
+    } while (snode && (snode->nodetype & (LYS_CHOICE | LYS_CASE)));
+}
+
+/**
+ * @brief Validate must conditions of a data node.
+ *
+ * @param[in] node Node to validate.
+ * @param[in] val_opts Validation options.
+ * @param[in] int_opts Internal parser options.
+ * @param[in] xpath_options Additional XPath options to use.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_must(const struct lyd_node *node, uint32_t val_opts, uint32_t int_opts, uint32_t xpath_options)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    struct lyxp_set xp_set;
+    struct lysc_must *musts;
+    const struct lyd_node *tree;
+    const struct lysc_node *schema;
+    const char *emsg, *eapptag;
+    LY_ARRAY_COUNT_TYPE u;
+
+    assert((int_opts & (LYD_INTOPT_RPC | LYD_INTOPT_REPLY)) != (LYD_INTOPT_RPC | LYD_INTOPT_REPLY));
+    assert((int_opts & (LYD_INTOPT_ACTION | LYD_INTOPT_REPLY)) != (LYD_INTOPT_ACTION | LYD_INTOPT_REPLY));
+
+    if (node->schema->nodetype & (LYS_ACTION | LYS_RPC)) {
+        if (int_opts & (LYD_INTOPT_RPC | LYD_INTOPT_ACTION)) {
+            schema = &((struct lysc_node_action *)node->schema)->input.node;
+        } else if (int_opts & LYD_INTOPT_REPLY) {
+            schema = &((struct lysc_node_action *)node->schema)->output.node;
+        } else {
+            LOGINT_RET(LYD_CTX(node));
+        }
+    } else {
+        schema = node->schema;
+    }
+    musts = lysc_node_musts(schema);
+    if (!musts) {
+        /* no must to evaluate */
+        return LY_SUCCESS;
+    }
+
+    /* find first top-level node */
+    for (tree = node; tree->parent; tree = lyd_parent(tree)) {}
+    tree = lyd_first_sibling(tree);
+
+    LY_ARRAY_FOR(musts, u) {
+        memset(&xp_set, 0, sizeof xp_set);
+
+        /* evaluate must */
+        r = lyxp_eval(LYD_CTX(node), musts[u].cond, node->schema->module, LY_VALUE_SCHEMA_RESOLVED,
+                musts[u].prefixes, node, node, tree, NULL, &xp_set, LYXP_SCHEMA | xpath_options);
+        if (r == LY_EINCOMPLETE) {
+            LOGERR(LYD_CTX(node), LY_EINCOMPLETE,
+                    "Must \"%s\" depends on a node with a when condition, which has not been evaluated.", musts[u].cond->expr);
+        }
+        LY_CHECK_ERR_GOTO(r, rc = r, cleanup);
+
+        /* check the result */
+        lyxp_set_cast(&xp_set, LYXP_SET_BOOLEAN);
+        if (!xp_set.val.bln) {
+            if (val_opts & LYD_VALIDATE_OPERATIONAL) {
+                /* only a warning */
+                emsg = musts[u].emsg;
+                LOG_LOCSET(NULL, node);
+                if (emsg) {
+                    LOGWRN(LYD_CTX(node), "%s", emsg);
+                } else {
+                    LOGWRN(LYD_CTX(node), "Must condition \"%s\" not satisfied.", musts[u].cond->expr);
+                }
+                LOG_LOCBACK(0, 1);
+            } else {
+                /* use specific error information */
+                emsg = musts[u].emsg;
+                eapptag = musts[u].eapptag ? musts[u].eapptag : "must-violation";
+                LOG_LOCSET(NULL, node);
+                if (emsg) {
+                    LOGVAL_APPTAG(LYD_CTX(node), eapptag, LYVE_DATA, "%s", emsg);
+                } else {
+                    LOGVAL_APPTAG(LYD_CTX(node), eapptag, LY_VCODE_NOMUST, musts[u].cond->expr);
+                }
+                LOG_LOCBACK(0, 1);
+                r = LY_EVALID;
+                LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+            }
+        }
+    }
+
+cleanup:
+    return rc;
+}
+
+/**
+ * @brief Perform all remaining validation tasks, the data tree must be final when calling this function.
+ *
+ * @param[in] first First sibling.
+ * @param[in] parent Data parent.
+ * @param[in] sparent Schema parent of the siblings, NULL for top-level siblings.
+ * @param[in] mod Module of the siblings, NULL for nested siblings.
+ * @param[in] val_opts Validation options (@ref datavalidationoptions).
+ * @param[in] int_opts Internal parser options.
+ * @param[in] must_xp_opts Additional XPath options to use for evaluating "must".
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_final_r(struct lyd_node *first, const struct lyd_node *parent, const struct lysc_node *sparent,
+        const struct lys_module *mod, uint32_t val_opts, uint32_t int_opts, uint32_t must_xp_opts)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    const char *innode;
+    struct lyd_node *node;
+
+    /* validate all restrictions of nodes themselves */
+    LY_LIST_FOR(first, node) {
+        if (node->flags & LYD_EXT) {
+            /* ext instance data should have already been validated */
+            continue;
+        }
+
+        /* opaque data */
+        if (!node->schema) {
+            r = lyd_parse_opaq_error(node);
+            goto next_iter;
+        }
+
+        if (!node->parent && mod && (lyd_owner_module(node) != mod)) {
+            /* all top-level data from this module checked */
+            break;
+        }
+
+        /* no state/input/output/op data */
+        innode = NULL;
+        if ((val_opts & LYD_VALIDATE_NO_STATE) && (node->schema->flags & LYS_CONFIG_R)) {
+            innode = "state";
+        } else if ((int_opts & (LYD_INTOPT_RPC | LYD_INTOPT_ACTION)) && (node->schema->flags & LYS_IS_OUTPUT)) {
+            innode = "output";
+        } else if ((int_opts & LYD_INTOPT_REPLY) && (node->schema->flags & LYS_IS_INPUT)) {
+            innode = "input";
+        } else if (!(int_opts & (LYD_INTOPT_RPC | LYD_INTOPT_REPLY)) && (node->schema->nodetype == LYS_RPC)) {
+            innode = "rpc";
+        } else if (!(int_opts & (LYD_INTOPT_ACTION | LYD_INTOPT_REPLY)) && (node->schema->nodetype == LYS_ACTION)) {
+            innode = "action";
+        } else if (!(int_opts & LYD_INTOPT_NOTIF) && (node->schema->nodetype == LYS_NOTIF)) {
+            innode = "notification";
+        }
+        if (innode) {
+            LOG_LOCSET(NULL, node);
+            LOGVAL(LYD_CTX(node), LY_VCODE_UNEXPNODE, innode, node->schema->name);
+            LOG_LOCBACK(0, 1);
+            r = LY_EVALID;
+            goto next_iter;
+        }
+
+        /* obsolete data */
+        lyd_validate_obsolete(node);
+
+        /* node's musts */
+        if ((r = lyd_validate_must(node, val_opts, int_opts, must_xp_opts))) {
+            goto next_iter;
+        }
+
+        /* node value was checked by plugins */
+
+next_iter:
+        LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+    }
+
+    /* validate schema-based restrictions */
+    r = lyd_validate_siblings_schema_r(first, parent, sparent, mod ? mod->compiled : NULL, val_opts, int_opts);
+    LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+    LY_LIST_FOR(first, node) {
+        if (!node->schema || (!node->parent && mod && (lyd_owner_module(node) != mod))) {
+            /* only opaque data following or all top-level data from this module checked */
+            break;
+        }
+
+        /* validate all children recursively */
+        r = lyd_validate_final_r(lyd_child(node), node, node->schema, NULL, val_opts, int_opts, must_xp_opts);
+        LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+        /* set default for containers */
+        lyd_cont_set_dflt(node);
+    }
+
+cleanup:
+    return rc;
+}
+
+/**
+ * @brief Validate extension instance data by storing it in its unres set.
+ *
+ * @param[in] sibling First sibling with ::LYD_EXT flag, all the following ones are expected to have it, too.
+ * @param[in,out] ext_val Set with parsed extension instance data to validate.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_nested_ext(struct lyd_node *sibling, struct ly_set *ext_val)
+{
+    struct lyd_node *node;
+    struct lyd_ctx_ext_val *ext_v;
+    struct lysc_ext_instance *nested_exts, *ext = NULL;
+    LY_ARRAY_COUNT_TYPE u;
+
+    /* check of basic assumptions */
+    if (!sibling->parent || !sibling->parent->schema) {
+        LOGINT_RET(LYD_CTX(sibling));
+    }
+    LY_LIST_FOR(sibling, node) {
+        if (!(node->flags & LYD_EXT)) {
+            LOGINT_RET(LYD_CTX(sibling));
+        }
+    }
+
+    /* try to find the extension instance */
+    nested_exts = sibling->parent->schema->exts;
+    LY_ARRAY_FOR(nested_exts, u) {
+        if (nested_exts[u].def->plugin->validate) {
+            if (ext) {
+                /* more extension instances with validate callback */
+                LOGINT_RET(LYD_CTX(sibling));
+            }
+            ext = &nested_exts[u];
+        }
+    }
+    if (!ext) {
+        /* no extension instance with validate callback */
+        LOGINT_RET(LYD_CTX(sibling));
+    }
+
+    /* store for validation */
+    ext_v = malloc(sizeof *ext_v);
+    LY_CHECK_ERR_RET(!ext_v, LOGMEM(LYD_CTX(sibling)), LY_EMEM);
+    ext_v->ext = ext;
+    ext_v->sibling = sibling;
+    LY_CHECK_RET(ly_set_add(ext_val, ext_v, 1, NULL));
+
+    return LY_SUCCESS;
+}
+
+LY_ERR
+lyd_validate_node_ext(struct lyd_node *node, struct ly_set *ext_node)
+{
+    struct lyd_ctx_ext_node *ext_n;
+    struct lysc_ext_instance *exts;
+    LY_ARRAY_COUNT_TYPE u;
+
+    /* try to find a relevant extension instance with node callback */
+    exts = node->schema->exts;
+    LY_ARRAY_FOR(exts, u) {
+        if (exts[u].def->plugin && exts[u].def->plugin->node) {
+            /* store for validation */
+            ext_n = malloc(sizeof *ext_n);
+            LY_CHECK_ERR_RET(!ext_n, LOGMEM(LYD_CTX(node)), LY_EMEM);
+            ext_n->ext = &exts[u];
+            ext_n->node = node;
+            LY_CHECK_RET(ly_set_add(ext_node, ext_n, 1, NULL));
+        }
+    }
+
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Validate the whole data subtree.
+ *
+ * @param[in] root Subtree root.
+ * @param[in,out] node_when Set for nodes with when conditions.
+ * @param[in,out] node_types Set for unres node types.
+ * @param[in,out] meta_types Set for unres metadata types.
+ * @param[in,out] ext_node Set with nodes with extensions to validate.
+ * @param[in,out] ext_val Set for parsed extension data to validate.
+ * @param[in] val_opts Validation options.
+ * @param[in,out] diff Validation diff.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lyd_validate_subtree(struct lyd_node *root, struct ly_set *node_when, struct ly_set *node_types,
+        struct ly_set *meta_types, struct ly_set *ext_node, struct ly_set *ext_val, uint32_t val_opts,
+        struct lyd_node **diff)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    const struct lyd_meta *meta;
+    const struct lysc_type *type;
+    struct lyd_node *node;
+    uint32_t impl_opts;
+
+    LYD_TREE_DFS_BEGIN(root, node) {
+        if (node->flags & LYD_EXT) {
+            /* validate using the extension instance callback */
+            return lyd_validate_nested_ext(node, ext_val);
+        }
+
+        if (!node->schema) {
+            /* do not validate opaque nodes */
+            goto next_node;
+        }
+
+        LY_LIST_FOR(node->meta, meta) {
+            lyplg_ext_get_storage(meta->annotation, LY_STMT_TYPE, sizeof type, (const void **)&type);
+            if (type->plugin->validate) {
+                /* metadata type resolution */
+                r = ly_set_add(meta_types, (void *)meta, 1, NULL);
+                LY_CHECK_ERR_GOTO(r, rc = r, cleanup);
+            }
+        }
+
+        if ((node->schema->nodetype & LYD_NODE_TERM) && ((struct lysc_node_leaf *)node->schema)->type->plugin->validate) {
+            /* node type resolution */
+            r = ly_set_add(node_types, (void *)node, 1, NULL);
+            LY_CHECK_ERR_GOTO(r, rc = r, cleanup);
+        } else if (node->schema->nodetype & LYD_NODE_INNER) {
+            /* new node validation, autodelete */
+            r = lyd_validate_new(lyd_node_child_p(node), node->schema, NULL, val_opts, diff);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+            /* add nested defaults */
+            impl_opts = 0;
+            if (val_opts & LYD_VALIDATE_NO_STATE) {
+                impl_opts |= LYD_IMPLICIT_NO_STATE;
+            }
+            if (val_opts & LYD_VALIDATE_NO_DEFAULTS) {
+                impl_opts |= LYD_IMPLICIT_NO_DEFAULTS;
+            }
+            r = lyd_new_implicit_r(node, lyd_node_child_p(node), NULL, NULL, NULL, NULL, NULL, impl_opts, diff);
+            LY_CHECK_ERR_GOTO(r, rc = r, cleanup);
+        }
+
+        if (lysc_has_when(node->schema)) {
+            /* when evaluation */
+            r = ly_set_add(node_when, (void *)node, 1, NULL);
+            LY_CHECK_ERR_GOTO(r, rc = r, cleanup);
+        }
+
+        /* store for ext instance node validation, if needed */
+        r = lyd_validate_node_ext(node, ext_node);
+        LY_CHECK_ERR_GOTO(r, rc = r, cleanup);
+
+next_node:
+        LYD_TREE_DFS_END(root, node);
+    }
+
+cleanup:
+    return rc;
+}
+
+LY_ERR
+lyd_validate(struct lyd_node **tree, const struct lys_module *module, const struct ly_ctx *ctx, uint32_t val_opts,
+        ly_bool validate_subtree, struct ly_set *node_when_p, struct ly_set *node_types_p, struct ly_set *meta_types_p,
+        struct ly_set *ext_node_p, struct ly_set *ext_val_p, struct lyd_node **diff)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    struct lyd_node *first, *next, **first2, *iter;
+    const struct lys_module *mod;
+    struct ly_set node_types = {0}, meta_types = {0}, node_when = {0}, ext_node = {0}, ext_val = {0};
+    uint32_t i = 0, impl_opts;
+
+    assert(tree && ctx);
+    assert((node_when_p && node_types_p && meta_types_p && ext_node_p && ext_val_p) ||
+            (!node_when_p && !node_types_p && !meta_types_p && !ext_node_p && !ext_val_p));
+
+    if (!node_when_p) {
+        node_when_p = &node_when;
+        node_types_p = &node_types;
+        meta_types_p = &meta_types;
+        ext_node_p = &ext_node;
+        ext_val_p = &ext_val;
+    }
+
+    next = *tree;
+    while (1) {
+        if (val_opts & LYD_VALIDATE_PRESENT) {
+            mod = lyd_data_next_module(&next, &first);
+        } else {
+            mod = lyd_mod_next_module(next, module, ctx, &i, &first);
+        }
+        if (!mod) {
+            break;
+        }
+        if (!first || (first == *tree)) {
+            /* make sure first2 changes are carried to tree */
+            first2 = tree;
+        } else {
+            first2 = &first;
+        }
+
+        /* validate new top-level nodes of this module, autodelete */
+        r = lyd_validate_new(first2, *first2 ? lysc_data_parent((*first2)->schema) : NULL, mod, val_opts, diff);
+        LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+        /* add all top-level defaults for this module, if going to validate subtree, do not add into unres sets
+         * (lyd_validate_subtree() adds all the nodes in that case) */
+        impl_opts = 0;
+        if (val_opts & LYD_VALIDATE_NO_STATE) {
+            impl_opts |= LYD_IMPLICIT_NO_STATE;
+        }
+        if (val_opts & LYD_VALIDATE_NO_DEFAULTS) {
+            impl_opts |= LYD_IMPLICIT_NO_DEFAULTS;
+        }
+        r = lyd_new_implicit_r(lyd_parent(*first2), first2, NULL, mod, validate_subtree ? NULL : node_when_p,
+                validate_subtree ? NULL : node_types_p, validate_subtree ? NULL : ext_node_p, impl_opts, diff);
+        LY_CHECK_ERR_GOTO(r, rc = r, cleanup);
+
+        /* our first module node pointer may no longer be the first */
+        first = *first2;
+        lyd_first_module_sibling(&first, mod);
+        if (!first || (first == *tree)) {
+            first2 = tree;
+        } else {
+            first2 = &first;
+        }
+
+        if (validate_subtree) {
+            /* process nested nodes */
+            LY_LIST_FOR(*first2, iter) {
+                if (lyd_owner_module(iter) != mod) {
+                    break;
+                }
+
+                r = lyd_validate_subtree(iter, node_when_p, node_types_p, meta_types_p, ext_node_p, ext_val_p,
+                        val_opts, diff);
+                LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+            }
+        }
+
+        /* finish incompletely validated terminal values/attributes and when conditions */
+        r = lyd_validate_unres(first2, mod, LYD_TYPE_DATA_YANG, node_when_p, 0, node_types_p, meta_types_p,
+                ext_node_p, ext_val_p, val_opts, diff);
+        LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+        if (!(val_opts & LYD_VALIDATE_NOT_FINAL)) {
+            /* perform final validation that assumes the data tree is final */
+            r = lyd_validate_final_r(*first2, NULL, NULL, mod, val_opts, 0, 0);
+            LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+        }
+    }
+
+cleanup:
+    ly_set_erase(&node_when, NULL);
+    ly_set_erase(&node_types, NULL);
+    ly_set_erase(&meta_types, NULL);
+    ly_set_erase(&ext_node, free);
+    ly_set_erase(&ext_val, free);
+    return rc;
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_validate_all(struct lyd_node **tree, const struct ly_ctx *ctx, uint32_t val_opts, struct lyd_node **diff)
+{
+    LY_CHECK_ARG_RET(NULL, tree, *tree || ctx, LY_EINVAL);
+    LY_CHECK_CTX_EQUAL_RET(*tree ? LYD_CTX(*tree) : NULL, ctx, LY_EINVAL);
+    if (!ctx) {
+        ctx = LYD_CTX(*tree);
+    }
+    if (diff) {
+        *diff = NULL;
+    }
+
+    return lyd_validate(tree, NULL, ctx, val_opts, 1, NULL, NULL, NULL, NULL, NULL, diff);
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_validate_module(struct lyd_node **tree, const struct lys_module *module, uint32_t val_opts, struct lyd_node **diff)
+{
+    LY_CHECK_ARG_RET(NULL, tree, module, !(val_opts & LYD_VALIDATE_PRESENT), LY_EINVAL);
+    LY_CHECK_CTX_EQUAL_RET(*tree ? LYD_CTX(*tree) : NULL, module->ctx, LY_EINVAL);
+    if (diff) {
+        *diff = NULL;
+    }
+
+    return lyd_validate(tree, module, module->ctx, val_opts, 1, NULL, NULL, NULL, NULL, NULL, diff);
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_validate_module_final(struct lyd_node *tree, const struct lys_module *module, uint32_t val_opts)
+{
+    LY_ERR r, rc = LY_SUCCESS;
+    struct lyd_node *first;
+    const struct lys_module *mod;
+    uint32_t i = 0;
+
+    LY_CHECK_ARG_RET(NULL, module, !(val_opts & (LYD_VALIDATE_PRESENT | LYD_VALIDATE_NOT_FINAL)), LY_EINVAL);
+    LY_CHECK_CTX_EQUAL_RET(tree ? LYD_CTX(tree) : NULL, module->ctx, LY_EINVAL);
+
+    /* module is unchanged but we need to get the first module data node */
+    mod = lyd_mod_next_module(tree, module, module->ctx, &i, &first);
+    assert(mod);
+
+    /* perform final validation that assumes the data tree is final */
+    r = lyd_validate_final_r(first, NULL, NULL, mod, val_opts, 0, 0);
+    LY_VAL_ERR_GOTO(r, rc = r, val_opts, cleanup);
+
+cleanup:
+    return rc;
+}
+
+/**
+ * @brief Find nodes for merging an operation into data tree for validation.
+ *
+ * @param[in] op_tree Full operation data tree.
+ * @param[in] op_node Operation node itself.
+ * @param[in] tree Data tree to be merged into.
+ * @param[out] op_subtree Operation subtree to merge.
+ * @param[out] tree_sibling Data tree sibling to merge next to, is set if @p tree_parent is NULL.
+ * @param[out] tree_parent Data tree parent to merge into, is set if @p tree_sibling is NULL.
+ */
+static void
+lyd_val_op_merge_find(const struct lyd_node *op_tree, const struct lyd_node *op_node, const struct lyd_node *tree,
+        struct lyd_node **op_subtree, struct lyd_node **tree_sibling, struct lyd_node **tree_parent)
+{
+    const struct lyd_node *tree_iter, *op_iter;
+    struct lyd_node *match = NULL;
+    uint32_t i, cur_depth, op_depth;
+
+    *op_subtree = NULL;
+    *tree_sibling = NULL;
+    *tree_parent = NULL;
+
+    /* learn op depth (top-level being depth 0) */
+    op_depth = 0;
+    for (op_iter = op_node; op_iter != op_tree; op_iter = lyd_parent(op_iter)) {
+        ++op_depth;
+    }
+
+    /* find where to merge op */
+    tree_iter = tree;
+    cur_depth = op_depth;
+    while (cur_depth && tree_iter) {
+        /* find op iter in tree */
+        lyd_find_sibling_first(tree_iter, op_iter, &match);
+        if (!match) {
+            break;
+        }
+
+        /* move tree_iter */
+        tree_iter = lyd_child(match);
+
+        /* move depth */
+        --cur_depth;
+
+        /* find next op parent */
+        op_iter = op_node;
+        for (i = 0; i < cur_depth; ++i) {
+            op_iter = lyd_parent(op_iter);
+        }
+    }
+
+    assert(op_iter);
+    *op_subtree = (struct lyd_node *)op_iter;
+    if (!tree || tree_iter) {
+        /* there is no tree whatsoever or this is the last found sibling */
+        *tree_sibling = (struct lyd_node *)tree_iter;
+    } else {
+        /* matching parent was found but it has no children to insert next to */
+        assert(match);
+        *tree_parent = match;
+    }
+}
+
+/**
+ * @brief Validate an RPC/action request, reply, or notification.
+ *
+ * @param[in] op_tree Full operation data tree.
+ * @param[in] op_node Operation node itself.
+ * @param[in] dep_tree Tree to be used for validating references from the operation subtree.
+ * @param[in] int_opts Internal parser options.
+ * @param[in] data_type Type of validated data.
+ * @param[in] validate_subtree Whether subtree was already validated (as part of data parsing) or not (separate validation).
+ * @param[in] node_when_p Set of nodes with when conditions, if NULL a local set is used.
+ * @param[in] node_types_p Set of unres node types, if NULL a local set is used.
+ * @param[in] meta_types_p Set of unres metadata types, if NULL a local set is used.
+ * @param[in] ext_node_p Set of unres nodes with extensions to validate, if NULL a local set is used.
+ * @param[in] ext_val_p Set of parsed extension data to validate, if NULL a local set is used.
+ * @param[out] diff Optional diff with any changes made by the validation.
+ * @return LY_SUCCESS on success.
+ * @return LY_ERR error on error.
+ */
+static LY_ERR
+_lyd_validate_op(struct lyd_node *op_tree, struct lyd_node *op_node, const struct lyd_node *dep_tree, enum lyd_type data_type,
+        uint32_t int_opts, ly_bool validate_subtree, struct ly_set *node_when_p, struct ly_set *node_types_p,
+        struct ly_set *meta_types_p,  struct ly_set *ext_node_p, struct ly_set *ext_val_p, struct lyd_node **diff)
+{
+    LY_ERR rc = LY_SUCCESS;
+    struct lyd_node *tree_sibling, *tree_parent, *op_subtree, *op_parent, *op_sibling_before, *op_sibling_after, *child;
+    struct ly_set node_types = {0}, meta_types = {0}, node_when = {0}, ext_node = {0}, ext_val = {0};
+
+    assert(op_tree && op_node);
+    assert((node_when_p && node_types_p && meta_types_p && ext_node_p && ext_val_p) ||
+            (!node_when_p && !node_types_p && !meta_types_p && !ext_node_p && !ext_val_p));
+
+    if (!node_when_p) {
+        node_when_p = &node_when;
+        node_types_p = &node_types;
+        meta_types_p = &meta_types;
+        ext_node_p = &ext_node;
+        ext_val_p = &ext_val;
+    }
+
+    /* merge op_tree into dep_tree */
+    lyd_val_op_merge_find(op_tree, op_node, dep_tree, &op_subtree, &tree_sibling, &tree_parent);
+    op_sibling_before = op_subtree->prev->next ? op_subtree->prev : NULL;
+    op_sibling_after = op_subtree->next;
+    op_parent = lyd_parent(op_subtree);
+
+    lyd_unlink(op_subtree);
+    lyd_insert_node(tree_parent, &tree_sibling, op_subtree, LYD_INSERT_NODE_DEFAULT);
+    if (!dep_tree) {
+        dep_tree = tree_sibling;
+    }
+
+    if (int_opts & LYD_INTOPT_REPLY) {
+        /* add output children defaults */
+        rc = lyd_new_implicit_r(op_node, lyd_node_child_p(op_node), NULL, NULL, node_when_p, node_types_p,
+                ext_node_p, LYD_IMPLICIT_OUTPUT, diff);
+        LY_CHECK_GOTO(rc, cleanup);
+
+        if (validate_subtree) {
+            /* skip validating the operation itself, go to children directly */
+            LY_LIST_FOR(lyd_child(op_node), child) {
+                rc = lyd_validate_subtree(child, node_when_p, node_types_p, meta_types_p, ext_node_p, ext_val_p, 0, diff);
+                LY_CHECK_GOTO(rc, cleanup);
+            }
+        }
+    } else {
+        if (validate_subtree) {
+            /* prevalidate whole operation subtree */
+            rc = lyd_validate_subtree(op_node, node_when_p, node_types_p, meta_types_p, ext_node_p, ext_val_p, 0, diff);
+            LY_CHECK_GOTO(rc, cleanup);
+        }
+    }
+
+    /* finish incompletely validated terminal values/attributes and when conditions on the full tree,
+     * account for unresolved 'when' that may appear in the non-validated dependency data tree */
+    LY_CHECK_GOTO(rc = lyd_validate_unres((struct lyd_node **)&dep_tree, NULL, data_type, node_when_p, LYXP_IGNORE_WHEN,
+            node_types_p, meta_types_p, ext_node_p, ext_val_p, 0, diff), cleanup);
+
+    /* perform final validation of the operation/notification */
+    lyd_validate_obsolete(op_node);
+    LY_CHECK_GOTO(rc = lyd_validate_must(op_node, 0, int_opts, LYXP_IGNORE_WHEN), cleanup);
+
+    /* final validation of all the descendants */
+    rc = lyd_validate_final_r(lyd_child(op_node), op_node, op_node->schema, NULL, 0, int_opts, LYXP_IGNORE_WHEN);
+    LY_CHECK_GOTO(rc, cleanup);
+
+cleanup:
+    /* restore operation tree */
+    lyd_unlink(op_subtree);
+    if (op_sibling_before) {
+        lyd_insert_after_node(NULL, op_sibling_before, op_subtree);
+        lyd_insert_hash(op_subtree);
+    } else if (op_sibling_after) {
+        lyd_insert_before_node(op_sibling_after, op_subtree);
+        lyd_insert_hash(op_subtree);
+    } else if (op_parent) {
+        lyd_insert_node(op_parent, NULL, op_subtree, LYD_INSERT_NODE_DEFAULT);
+    }
+
+    ly_set_erase(&node_when, NULL);
+    ly_set_erase(&node_types, NULL);
+    ly_set_erase(&meta_types, NULL);
+    ly_set_erase(&ext_node, free);
+    ly_set_erase(&ext_val, free);
+    return rc;
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_validate_op(struct lyd_node *op_tree, const struct lyd_node *dep_tree, enum lyd_type data_type, struct lyd_node **diff)
+{
+    struct lyd_node *op_node;
+    uint32_t int_opts;
+    struct ly_set ext_val = {0};
+    LY_ERR rc;
+
+    LY_CHECK_ARG_RET(NULL, op_tree, !dep_tree || !dep_tree->parent, (data_type == LYD_TYPE_RPC_YANG) ||
+            (data_type == LYD_TYPE_NOTIF_YANG) || (data_type == LYD_TYPE_REPLY_YANG), LY_EINVAL);
+    if (diff) {
+        *diff = NULL;
+    }
+    if (data_type == LYD_TYPE_RPC_YANG) {
+        int_opts = LYD_INTOPT_RPC | LYD_INTOPT_ACTION;
+    } else if (data_type == LYD_TYPE_NOTIF_YANG) {
+        int_opts = LYD_INTOPT_NOTIF;
+    } else {
+        int_opts = LYD_INTOPT_REPLY;
+    }
+
+    if (op_tree->schema && (op_tree->schema->nodetype & (LYS_RPC | LYS_ACTION | LYS_NOTIF))) {
+        /* we have the operation/notification, adjust the pointers */
+        op_node = op_tree;
+        while (op_tree->parent) {
+            op_tree = lyd_parent(op_tree);
+        }
+    } else {
+        /* find the operation/notification */
+        while (op_tree->parent) {
+            op_tree = lyd_parent(op_tree);
+        }
+        LYD_TREE_DFS_BEGIN(op_tree, op_node) {
+            if (!op_node->schema) {
+                return lyd_parse_opaq_error(op_node);
+            } else if (op_node->flags & LYD_EXT) {
+                /* fully validate the rest using the extension instance callback */
+                LY_CHECK_RET(lyd_validate_nested_ext(op_node, &ext_val));
+                rc = lyd_validate_unres((struct lyd_node **)&dep_tree, NULL, data_type, NULL, 0, NULL, NULL, NULL,
+                        &ext_val, 0, diff);
+                ly_set_erase(&ext_val, free);
+                return rc;
+            }
+
+            if ((int_opts & (LYD_INTOPT_RPC | LYD_INTOPT_ACTION | LYD_INTOPT_REPLY)) &&
+                    (op_node->schema->nodetype & (LYS_RPC | LYS_ACTION))) {
+                break;
+            } else if ((int_opts & LYD_INTOPT_NOTIF) && (op_node->schema->nodetype == LYS_NOTIF)) {
+                break;
+            }
+            LYD_TREE_DFS_END(op_tree, op_node);
+        }
+    }
+
+    if (int_opts & (LYD_INTOPT_RPC | LYD_INTOPT_ACTION | LYD_INTOPT_REPLY)) {
+        if (!op_node || !(op_node->schema->nodetype & (LYS_RPC | LYS_ACTION))) {
+            LOGERR(LYD_CTX(op_tree), LY_EINVAL, "No RPC/action to validate found.");
+            return LY_EINVAL;
+        }
+    } else {
+        if (!op_node || (op_node->schema->nodetype != LYS_NOTIF)) {
+            LOGERR(LYD_CTX(op_tree), LY_EINVAL, "No notification to validate found.");
+            return LY_EINVAL;
+        }
+    }
+
+    /* validate */
+    return _lyd_validate_op(op_tree, op_node, dep_tree, data_type, int_opts, 1, NULL, NULL, NULL, NULL, NULL, diff);
+}