Add CBOR Support to libyang (#2130)

CMakeLists.txt

@@ -238,6 +238,7 @@ set(format_sources
     src/*.h
     src/plugins_exts/*
     src/plugins_types/*)
+
 #
 # options
 #
@@ -323,6 +324,15 @@ if(ENABLE_COVERAGE)
     gen_coverage_enable(${ENABLE_TESTS})
 endif()
 
+find_package(CBOR)
+if(CBOR_FOUND)
+    list(APPEND libsrc src/parser_cbor.c src/lcbor.c src/printer_cbor.c)
+    list(APPEND headers src/lcbor.h)
+    list(APPEND format_sources src/parser_cbor.c src/lcbor.h src/lcbor.c src/printer_cbor.c)
+else()
+    message(STATUS "libcbor not found, CBOR support disabled")
+endif()
+
 if ("${BUILD_TYPE_UPPER}" STREQUAL "DEBUG")
     # enable before adding tests to let them detect that format checking is available - one of the tests is format checking
     source_format_enable(0.77)
@@ -427,6 +437,17 @@ find_package(PCRE2 10.21 REQUIRED)
 include_directories(${PCRE2_INCLUDE_DIRS})
 target_link_libraries(yang ${PCRE2_LIBRARIES})
 
+# link libcbor if found
+if(CBOR_FOUND)
+    if(TARGET yangobj)
+        target_compile_definitions(yangobj PRIVATE ENABLE_CBOR_SUPPORT)
+        target_include_directories(yangobj PRIVATE ${CBOR_INCLUDE_DIR})
+    endif()
+    target_compile_definitions(yang PRIVATE ENABLE_CBOR_SUPPORT)
+    target_include_directories(yang PRIVATE ${CBOR_INCLUDE_DIR})
+    target_link_libraries(yang ${CBOR_LIBRARY})
+endif()
+
 # XXHash include and library
 find_package(XXHash)
 if(XXHASH_FOUND)
@@ -521,4 +542,4 @@ add_custom_target(cclean
         COMMAND make clean
         COMMAND find . -iname '*cmake*' -not -name CMakeLists.txt -not -path './CMakeModules*' -exec rm -rf {} +
         COMMAND rm -rf Makefile Doxyfile
-        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})

CMakeModules/FindCBOR.cmake

@@ -0,0 +1,37 @@
+# Try to find libcbor
+# Once done this will define
+#
+# Read-Only variables:
+#  CBOR_FOUND - system has libcbor
+#  CBOR_INCLUDE_DIR - the libcbor include directory
+#  CBOR_LIBRARY - Link these to use libcbor
+
+find_path(CBOR_INCLUDE_DIR
+    NAMES
+        cbor.h
+    PATHS
+        /usr/include
+        /usr/local/include
+        /opt/local/include
+        /sw/include
+        ${CMAKE_INCLUDE_PATH}
+        ${CMAKE_INSTALL_PREFIX}/include
+)
+
+find_library(CBOR_LIBRARY
+    NAMES
+        cbor
+        libcbor
+    PATHS
+        /usr/lib
+        /usr/lib64
+        /usr/local/lib
+        /usr/local/lib64
+        /opt/local/lib
+        /sw/lib
+        ${CMAKE_LIBRARY_PATH}
+        ${CMAKE_INSTALL_PREFIX}/lib
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(CBOR FOUND_VAR CBOR_FOUND REQUIRED_VARS CBOR_INCLUDE_DIR CBOR_LIBRARY)

src/lcbor.c

@@ -0,0 +1,117 @@
+/**
+ * @file lcbor.c
+ * @author MeherRushi <meherrrushi2@gmail.com>
+ * @brief CBOR data parser for libyang (abstraction over libcbor)
+ *
+ * Copyright (c) 2026 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
+ */
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "in_internal.h"
+#include "lcbor.h"
+#include "log.h"
+#include "ly_common.h"
+
+const char *
+lycbor_token2str(enum cbor_type cbortype)
+{
+    switch (cbortype) {
+    case CBOR_TYPE_UINT:
+        return "unsigned integer";
+    case CBOR_TYPE_NEGINT:
+        return "negative integer";
+    case CBOR_TYPE_BYTESTRING:
+        return "byte string";
+    case CBOR_TYPE_STRING:
+        return "string";
+    case CBOR_TYPE_ARRAY:
+        return "array";
+    case CBOR_TYPE_MAP:
+        return "map";
+    case CBOR_TYPE_TAG:
+        return "tag";
+    case CBOR_TYPE_FLOAT_CTRL:
+        return "decimals and special values (true, false, nil, ...)";
+    }
+
+    return "";
+}
+
+void
+lycbor_ctx_free(struct lycbor_ctx *cborctx)
+{
+    if (cborctx) {
+        if (cborctx->cbor_data) {
+            cbor_decref(&cborctx->cbor_data);
+        }
+        free(cborctx);
+    }
+}
+
+/**
+ * @brief Detect CBOR format variant from input data.
+ *
+ * @param[in] in Input structure to analyze.
+ * @param[out] format Detected format.
+ * @return LY_ERR value.
+ */
+static LY_ERR
+lydcbor_detect_format(struct ly_in *in, enum lyd_cbor_format *format)
+{
+    /* Simple heuristic: try to parse as CBOR and examine structure */
+    /* For now, default to named format */
+    (void)in;
+    *format = LYD_CBOR_NAMED;
+    return LY_SUCCESS;
+}
+
+LY_ERR
+lycbor_ctx_new(const struct ly_ctx *ctx, struct ly_in *in, struct lycbor_ctx **cborctx_p)
+{
+    /* TODO : Need to restructure error handling here */
+    LY_ERR ret = LY_SUCCESS;
+    struct lycbor_ctx *cborctx;
+    struct cbor_load_result result = {0};
+    enum lyd_cbor_format format;
+
+    assert(ctx && in && cborctx_p);
+
+    /* TODO : error handling after the detect_format function call */
+    ret = lydcbor_detect_format(in, &format);
+
+    /* Allocate and initialize CBOR context */
+    cborctx = calloc(1, sizeof *cborctx);
+    LY_CHECK_ERR_RET(!cborctx, LOGMEM(ctx), LY_EMEM);
+    cborctx->ctx = ctx;
+    cborctx->in = in;
+    cborctx->format = format;
+
+     /* input line logging */
+    ly_log_location(NULL, NULL, in);
+
+    /* load and parse CBOR data */
+    cborctx->cbor_data = cbor_load((cbor_data)in->current, in->length, &result);
+    if (!cborctx->cbor_data) {
+        LOGVAL(ctx, NULL, LYVE_SYNTAX, "Failed to parse CBOR data.");
+        free(cborctx);
+        return LY_EVALID;
+    }
+    if (result.error.code != CBOR_ERR_NONE) {
+        LOGVAL(ctx, NULL, LYVE_SYNTAX, "CBOR parsing error (code %d).", result.error.code);
+        cbor_decref(&cborctx->cbor_data);
+        free(cborctx);
+        return LY_EVALID;
+    }
+
+    *cborctx_p = cborctx;
+    return ret;
+}

src/lcbor.h

@@ -0,0 +1,79 @@
+/**
+ * @file lcbor.h
+ * @author MeherRushi <meherrrushi2@gmail.com>
+ * @brief CBOR data parser routines for libyang (abstraction over libcbor)
+ *
+ * Copyright (c) 2026 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
+ */
+
+#ifndef LY_CBOR_H_
+#define LY_CBOR_H_
+
+#include <stddef.h>
+#include <stdint.h>
+/* using libcbor as the low-level parser */
+#include <cbor.h>
+
+
+#include "log.h"
+#include "set.h"
+
+struct ly_ctx;
+struct ly_in;
+
+/**
+ * @brief CBOR format variants for different encoding schemes
+ */
+enum lyd_cbor_format
+{
+    LYD_CBOR_NAMED, /**< CBOR with named identifiers (JSON-like) */
+    LYD_CBOR_SID    /**< CBOR with Schema Item identifiers (future implementation) */
+};
+
+struct lycbor_ctx {
+    const struct ly_ctx *ctx;
+    struct ly_in *in;   /** input structure */
+
+    cbor_item_t *cbor_data; /**< parsed CBOR data */
+
+    enum lyd_cbor_format format; /**< CBOR format variant */
+
+    struct {
+        cbor_item_t *cbor_data; /**< parsed CBOR data */
+        enum lyd_cbor_format format; /**< CBOR format variant */
+        const char *input;
+    } backup;
+};
+
+/**
+ * @brief Get a human-readable name for a CBOR type.
+ *
+ * @param[in] cbortype CBOR type.
+ * @return String representation of the CBOR type.
+ */
+const char *lycbor_token2str(enum cbor_type cbortype);
+
+/**
+ * @brief Create new CBOR context for parsing.
+ *
+ * @param[in] ctx libyang context.
+ * @param[in] in CBOR string data to parse.
+ * @param[out] cborctx New CBOR parser context containing parsed CBOR data.
+ * @return LY_ERR value.
+ */
+LY_ERR lycbor_ctx_new(const struct ly_ctx *ctx, struct ly_in *in, struct lycbor_ctx **cborctx);
+
+/**
+ * @brief Free CBOR context.
+ *
+ * @param[in] cborctx CBOR context to free.
+ */
+void lycbor_ctx_free(struct lycbor_ctx *cborctx);
+
+#endif /* LY_CBOR_H_ */

src/log.h

@@ -286,6 +286,7 @@ typedef enum {
     LYVE_SEMANTICS,    /**< generic semantic error */
     LYVE_SYNTAX_XML,   /**< XML-related syntax error */
     LYVE_SYNTAX_JSON,  /**< JSON-related syntax error */
+    LYVE_SYNTAX_CBOR,  /**< CBOR-related syntax error */
     LYVE_DATA,         /**< YANG data does not reflect some of the module restrictions */
 
     LYVE_OTHER         /**< Unknown error */