9.1. Migrating from Anjay 2.2.5

9.1.1. Introduction

Most changes since Anjay 2.2.5 are minor, so no major changes in code flow are required when porting from Anjay 2.2. However, there has been a significant refactor in project structure, so some changes may be breaking for some users.

9.1.2. Change to minimum CMake version

Declared minimum CMake version necessary for CMake-based compilation, as well as for importing the installed library through find_package(), is now 3.6. If you’re using some Linux distribution that only has an older version in its repositories (notably, Ubuntu 16.04), we recommend using one of the following install methods instead:

This change does not affect users who compile the library using some alternative approach, without using the provided CMake scripts.

9.1.3. Changes in Anjay proper

9.1.3.1. Removal of ssize_t usages from Anjay APIs

Most changes in Anjay proper relate to the removal of usages of the POSIX-specific size_t type in Anjay and all related projects. See also Removal of ssize_t usages from avs_commons APIs.

Here is a summary of the relevant API changes:

  • Execute argument value getter

    • Old API:

      ssize_t anjay_execute_get_arg_value(anjay_execute_ctx_t *ctx,
                                          char *out_buf,
                                          size_t buf_size);
      
    • New API:

       int anjay_execute_get_arg_value(anjay_execute_ctx_t *ctx,
                                       size_t *out_bytes_read,
                                       char *out_buf,
                                       size_t buf_size);
      
    • Return value semantics have been aligned with those of anjay_get_string() - 0 is returned for success, negative value for error, or ANJAY_BUFFER_TOO_SHORT (1) if the buffer was too small.

      Length of the extracted data, which is equivalent to the old return value semantics, can be retrieved using the new out_bytes_read argument, but it can also be NULL if that is not necessary.

  • NIDD driver receive callback

    • Old API:

      typedef ssize_t anjay_nidd_driver_recv_t(anjay_nidd_driver_t *driver,
                                               void *out_message,
                                               size_t size,
                                               avs_time_monotonic_t deadline);
      
    • New API:

       typedef int anjay_nidd_driver_recv_t(anjay_nidd_driver_t *driver,
                                            size_t *out_bytes_received,
                                            void *out_message,
                                            size_t size,
                                            avs_time_monotonic_t deadline);
      
    • The callback shall now return 0 for all success conditions (i.e., for all the conditions when it previously returned a non-negative value).

      Number of bytes received shall now be returned using the new out_bytes_received argument.

  • Get line callback for the BG96 NIDD driver (as a commercial feature only)

    • Old API:

      typedef ssize_t anjay_bg96_nidd_getline_t(void *user_context,
                                                char *out_line_buffer,
                                                size_t buffer_size,
                                                avs_time_monotonic_t deadline);
      
    • New API:

       typedef int anjay_bg96_nidd_getline_t(void *user_context,
                                             char *out_line_buffer,
                                             size_t buffer_size,
                                             avs_time_monotonic_t deadline);
      
    • The callback shall now return 0 for all success conditions (i.e., for all the conditions when it previously returned a non-negative value).

      The length of returned data, which was the previous return value, is not actually used as it is implicit due to the requirement for string null-termination.

9.1.3.2. Refactor of the Attribute Storage module

The Attribute Storage feature is no longer a standalone module and has been moved to the library core. From the user perspective, this has the following consequences:

  • Explicit installation of this module in runtime is no longer necessary. The anjay_attr_storage_install() method has been removed.

  • The ANJAY_WITH_MODULE_ATTR_STORAGE configuration macro in anjay_config.h has been renamed to ANJAY_WITH_ATTR_STORAGE.

  • The WITH_MODULE_attr_storage CMake option (equivalent to the macro mentioned above) has been renamed to WITH_ATTR_STORAGE.

Additionally, the behavior of anjay_attr_storage_restore() has been changed - from now on, this function fails if supplied source stream is invalid and the Attribute Storage remains untouched. This change makes the function consistent with other anjay_*_restore() APIs.

9.1.3.3. Refactor of offline mode control API

Since Anjay 2.4, offline mode is configurable independently per every transport. Below is a list of removed functions and counterparts that should be used:

Removed function

Counterpart

anjay_is_offline()

anjay_transport_is_offline()

anjay_enter_offline()

anjay_transport_enter_offline()

anjay_exit_offline()

anjay_transport_exit_offline()

anjay_schedule_reconnect()

anjay_transport_schedule_reconnect()

New functions should be called with transport_set argument set to ANJAY_TRANSPORT_SET_ALL to achieve the same behavior.

9.1.3.4. Addition of the con attribute to public API

The con attribute, enabled via the WITH_CON_ATTR CMake option, has been previously supported as a custom extension. Since an identical flag has been standardized as part of LwM2M TS 1.2, it has been included in the public API as part of preparations to support the new protocol version.

If you initialize anjay_dm_oi_attributes_t or anjay_dm_r_attributes_t objects manually, you may need to initialize the new con field as well, since the empty ANJAY_DM_CON_ATTR_NONE value is NOT the default zero-initialized value.

As more new attributes may be added in future versions of Anjay, it is recommended to initialize such structures with ANJAY_DM_OI_ATTRIBUTES_EMPTY or ANJAY_DM_R_ATTRIBUTES_EMPTY constants, and then fill in the attributes you actually intend to set.

9.1.3.5. Default (D)TLS version

When the anjay_configuration_t::dtls_version field is set to AVS_NET_SSL_VERSION_DEFAULT (which includes the case of zero-initialization), Anjay 3.0 and earlier automatically mapped this setting to AVS_NET_SSL_VERSION_TLSv1_2 to ensure that (D)TLS 1.2 is used as mandated by the LwM2M specification.

This mapping has been removed in Anjay 3.1, which means that the default version configuration of the underlying (D)TLS library will be used. This has been done to automatically allow the use of newer protocols and deprecate old versions when the backend library is updated, without the need to update Anjay code. However, depending on the (D)TLS backend library used, this may lead to (D)TLS 1.1 or earlier being used if the server does not properly negotiate a higher version. Please explicitly set dtls_version to AVS_NET_SSL_VERSION_TLSv1_2 if you want to disallow this.

Please note that Mbed TLS 3.0 has dropped support for TLS 1.1 and earlier, so this change will not affect behavior with that library.

9.1.3.6. Other changes

  • Declaration of anjay_smsdrv_cleanup() has been moved from anjay/core.h to anjay/sms.h in versions that include the SMS commercial feature. It has been removed altogether from versions that do not support SMS.

  • The following compile-time constants have been removed. None of them have been actually used in Anjay 2.x:

    • MAX_FLOAT_STRING_SIZE

    • MAX_OBSERVABLE_RESOURCE_SIZE

  • Getter function for retrieving security information from data model

    • Old API:

      anjay_security_config_t *anjay_security_config_from_dm(anjay_t *anjay,
                                                             const char *uri);
      
    • New API:

      int anjay_security_config_from_dm(anjay_t *anjay,
                                        anjay_security_config_t *out_config,
                                        const char *uri);
      
    • The security configuration is now returned through an output argument with any necessary internal buffers cached inside the Anjay object instead of using heap allocation. Please refer to the Doxygen-based documentation of this function for details.

      Due to the change in lifetime requirements, no compatibility variant is provided.

  • NIDD driver MTU callback (as a commercial feature only)

    • Old API:

      typedef int anjay_nidd_driver_mtu_t(anjay_nidd_driver_t *driver,
                                          size_t *out_mtu);
      
    • New API:

       typedef int anjay_nidd_driver_outgoing_mtu_t(anjay_nidd_driver_t *driver,
                                                    size_t *out_mtu);
      
    • The current name is more descriptive. The behavior did not change. This handler was always designed for returning maximum number of bytes that can be sent through NIDD.

      An additional incoming_mtu callback can now also be specified. To retain compatibility with versions 2.4-2.4.1, it is permitted to specify only one of them and leave the other as NULL - in that case the returned value will be used as both outgoing and incoming MTU.

9.1.4. Changes in avs_coap

If you are using avs_coap APIs directly (e.g. when communicating over raw CoAP protocol), please note that following breaking changes in the avs_coap component:

  • In line with Anjay and avs_commons, to improve file name uniqueness, the avsystem/coap/config.h file has been renamed to avsystem/coap/avs_coap_config.h.

  • Moreover, context creation functions now take an explicit PRNG context argument:

    • UDP context creation

      • Old API:

        avs_coap_ctx_t *
        avs_coap_udp_ctx_create(avs_sched_t *sched,
                                const avs_coap_udp_tx_params_t *udp_tx_params,
                                avs_shared_buffer_t *in_buffer,
                                avs_shared_buffer_t *out_buffer,
                                avs_coap_udp_response_cache_t *cache);
        
      • New API:

          avs_coap_ctx_t *
          avs_coap_udp_ctx_create(avs_sched_t *sched,
                                  const avs_coap_udp_tx_params_t *udp_tx_params,
                                  avs_shared_buffer_t *in_buffer,
                                  avs_shared_buffer_t *out_buffer,
                                  avs_coap_udp_response_cache_t *cache,
                                  avs_crypto_prng_ctx_t *prng_ctx);
        
    • TCP context creation

      • Old API:

        avs_coap_ctx_t *avs_coap_tcp_ctx_create(avs_sched_t *sched,
                                                avs_shared_buffer_t *in_buffer,
                                                avs_shared_buffer_t *out_buffer,
                                                size_t max_opts_size,
                                                avs_time_duration_t request_timeout);
        
      • New API:

          avs_coap_ctx_t *avs_coap_tcp_ctx_create(avs_sched_t *sched,
                                                  avs_shared_buffer_t *in_buffer,
                                                  avs_shared_buffer_t *out_buffer,
                                                  size_t max_opts_size,
                                                  avs_time_duration_t request_timeout,
                                                  avs_crypto_prng_ctx_t *prng_ctx);
        

Note

It is now mandatory to pass a non-NULL value as the prng_ctx argument to the functions above.

9.1.5. Changes in avs_commons

avs_commons 4.1 and later contain a number of breaking changes compared to version 4.0 used by Anjay 2.2. If you are using any of the avs_commons APIs directly (which is especially likely for e.g. the logging API and querying sockets in the event loop), you will need to adjust your code.

9.1.5.1. avs_commons header rename

All headers of the avs_commons component have been renamed to make their names more unique. Please adjust your #include directives accordingly.

The general rename patterns are:

  • avsystem/commons/*.havsystem/commons/avs_*.h

  • avsystem/commons/stream/*.h, avsystem/commons/stream/stream_*.havsystem/commons/avs_stream_*.h

  • avsystem/commons/unit/*.havsystem/commons/avs_unit_*.h

Below is a detailed list of all renamed files:

Old header file

New header file

avsystem/commons/addrinfo.h

avsystem/commons/avs_addrinfo.h

avsystem/commons/aead.h

avsystem/commons/avs_aead.h

avsystem/commons/base64.h

avsystem/commons/avs_base64.h

avsystem/commons/buffer.h

avsystem/commons/avs_buffer.h

avsystem/commons/cleanup.h

avsystem/commons/avs_cleanup.h

avsystem/commons/condvar.h

avsystem/commons/avs_condvar.h

avsystem/commons/defs.h

avsystem/commons/avs_defs.h

avsystem/commons/errno.h

avsystem/commons/avs_errno.h

avsystem/commons/errno_map.h

avsystem/commons/avs_errno_map.h

avsystem/commons/hkdf.h

avsystem/commons/avs_hkdf.h

avsystem/commons/http.h

avsystem/commons/avs_http.h

avsystem/commons/init_once.h

avsystem/commons/avs_init_once.h

avsystem/commons/list.h

avsystem/commons/avs_list.h

avsystem/commons/log.h

avsystem/commons/avs_log.h

avsystem/commons/memory.h

avsystem/commons/avs_memory.h

avsystem/commons/mutex.h

avsystem/commons/avs_mutex.h

avsystem/commons/net.h

avsystem/commons/avs_net.h

avsystem/commons/persistence.h

avsystem/commons/avs_persistence.h

avsystem/commons/rbtree.h

avsystem/commons/avs_rbtree.h

avsystem/commons/sched.h

avsystem/commons/avs_sched.h

avsystem/commons/shared_buffer.h

avsystem/commons/avs_shared_buffer.h

avsystem/commons/socket.h

avsystem/commons/avs_socket.h
avsystem/commons/avs_crypto_pki.h 1

avsystem/commons/socket_v_table.h

avsystem/commons/avs_socket_v_table.h

avsystem/commons/stream.h

avsystem/commons/avs_stream.h

avsystem/commons/stream/stream_buffered.h

avsystem/commons/avs_stream_buffered.h

avsystem/commons/stream/stream_file.h

avsystem/commons/avs_stream_file.h

avsystem/commons/stream/stream_inbuf.h

avsystem/commons/avs_stream_inbuf.h

avsystem/commons/stream/md5.h

avsystem/commons/avs_stream_md5.h

avsystem/commons/stream/stream_membuf.h

avsystem/commons/avs_stream_membuf.h

avsystem/commons/stream/stream_net.h

avsystem/commons/avs_stream_net.h

avsystem/commons/stream/netbuf.h

avsystem/commons/avs_stream_netbuf.h

avsystem/commons/stream/stream_outbuf.h

avsystem/commons/avs_stream_outbuf.h

avsystem/commons/stream/stream_simple_io.h

avsystem/commons/avs_stream_simple_io.h

avsystem/commons/stream_v_table.h

avsystem/commons/avs_stream_v_table.h

avsystem/commons/time.h

avsystem/commons/avs_time.h

avsystem/commons/unit/memstream.h

avsystem/commons/avs_unit_memstream.h

avsystem/commons/unit/mock_helpers.h

avsystem/commons/avs_unit_mock_helpers.h

avsystem/commons/unit/mocksock.h

avsystem/commons/avs_unit_mocksock.h

avsystem/commons/unit/test.h

avsystem/commons/avs_unit_test.h

avsystem/commons/url.h

avsystem/commons/avs_url.h

avsystem/commons/utils.h

avsystem/commons/avs_utils.h

avsystem/commons/vector.h

avsystem/commons/avs_vector.h

1

Some symbols related to public-key cryptography have been refactored by moving from avsystem/commons/avs_socket.h to avsystem/commons/avs_crypto_pki.h, with additional renames. For details, see Move of public-key cryptography APIs from avs_net to avs_crypto.

9.1.5.2. Changes to avs_net socket API

Below is a reference of changes made to the avs_net socket API:

Old identifiers

New identifiers

Notes

avs_net_socket_create()
avs_net_udp_socket_create()
avs_net_tcp_socket_create()
avs_net_dtls_socket_create()
avs_net_ssl_socket_create()
The avs_net_socket_type_t enum is no longer used for socket creation. Separate functions are used instead, allowing for type-safe passing of the configuration structures.
avs_net_socket_decorate_in_place()
avs_net_dtls_socket_decorate_in_place()
avs_net_ssl_socket_decorate_in_place()
This change is analogous to the one above.
implicit
prng_ctx field in avs_net_ssl_configuration_t
Note: It is now mandatory to fill this field when instantiating a (D)TLS socket.

Note

With the introduction of the prng_ctx field in avs_net_ssl_configuration_t, the WITH_MBEDTLS_CUSTOM_ENTROPY_INITIALIZER compile-time option and the option to use a user-provided avs_net_mbedtls_entropy_init() function have been removed. If you relied on those features in your non-POSIX environment, please replace them with the new PRNG context mechanism. See Migrating mbed TLS custom entropy initializers for details.

9.1.5.2.1. Introduction of new socket option

avs_commons 4.10.1 bundled with Anjay 2.15.1 adds a new socket option key: AVS_NET_SOCKET_HAS_BUFFERED_DATA. This is used to make sure that when control is returned to the event loop, the poll() call will not stall waiting for new data that in reality has been already buffered and could be retrieved using the avs_commons APIs.

This is usually meaningful for (D)TLS connections, but for almost all simple unencrypted socket implementations, this should always return false.

This was previously achieved by always trying to receive more packets with timeout set to zero. However, it has been determined that such logic could lead to heavy blocking of the event loop in case communication with the network stack is relatively slow, e.g. on devices which implement TCP/IP sockets through modem AT commands.

If you maintain your own socket integration layer or (D)TLS integration layer, it is recommended that you add support for this option.

9.1.5.3. Removal of ssize_t usages from avs_commons APIs

All usages of the POSIX-specific ssize_t type in public APIs have been removed. Instead of replacing it with some other signed integer type, additional out-arguments have been introduced to functions that used it.

Below is a reference of related changes:

  • Base64 decode

    • Old APIs:

      ssize_t avs_base64_decode_custom(uint8_t *out,
                                       size_t out_length,
                                       const char *input,
                                       avs_base64_config_t config);
      // ...
      static inline ssize_t
      avs_base64_decode_strict(uint8_t *out, size_t out_length, const char *input) {
          // ...
      }
      // ...
      static inline ssize_t
      avs_base64_decode(uint8_t *out, size_t out_length, const char *input) {
          // ...
      }
      
    • New APIs:

       int avs_base64_decode_custom(size_t *out_bytes_decoded,
                                    uint8_t *out,
                                    size_t out_length,
                                    const char *input,
                                    avs_base64_config_t config);
       // ...
       static inline int avs_base64_decode_strict(size_t *out_bytes_decoded,
                                                  uint8_t *out,
                                                  size_t out_length,
                                                  const char *input) {
           // ...
       }
       // ...
       static inline int avs_base64_decode(size_t *out_bytes_decoded,
                                           uint8_t *out,
                                           size_t out_length,
                                           const char *input) {
           // ...
       }
      
  • Hexlify

    • Old API:

      ssize_t avs_hexlify(char *out_hex,
                          size_t out_size,
                          const void *input,
                          size_t input_size);
      
    • New API:

       int avs_hexlify(char *out_hex,
                       size_t out_size,
                       size_t *out_bytes_hexlified,
                       const void *input,
                       size_t input_size);
      
  • Unhexlify

    • Old API:

      ssize_t avs_unhexlify(uint8_t *output,
                            size_t out_size,
                            const char *input,
                            size_t in_size);
      
    • New API:

       int avs_unhexlify(size_t *out_bytes_written,
                         uint8_t *output,
                         size_t out_size,
                         const char *input,
                         size_t in_size);
      

Note

The new functions return 0 in all cases in which the old versions returned non-negative values. The value previously returned through the non-negative return value can be retrieved using the additional out-arguments, which have the same semantics. NULL can be passed to those out-arguments as well if that value is not needed.

The seemingly irregular placement of the new out-argument in avs_hexlify() is due to the fact that the semantics of that value is related to the input argument (hence it directly precedes it), not to the output buffer as is the case with the rest of these functions.

9.1.5.4. Move of public-key cryptography APIs from avs_net to avs_crypto

Public key cryptography APIs, previously defined in avsystem/commons/socket.h, have been moved into a new header called avsystem/commons/avs_crypto_pki.h.

Additionally, client-side and server-side certificate info structures are no longer separate, and both have been merged into a single type.

Here is a summary of renames:

Old symbol name

New symbol name

avs_net_trusted_cert_info_t
avs_net_client_cert_info_t

avs_crypto_certificate_chain_info_t

avs_net_client_key_info_t

avs_crypto_private_key_info_t

avs_net_security_info_union_t

avs_crypto_security_info_union_t

avs_net_trusted_cert_info_from_buffer()
avs_net_client_cert_info_from_buffer()

avs_crypto_certificate_chain_info_from_buffer()

avs_net_trusted_cert_info_from_file()
avs_net_client_cert_info_from_file()

avs_crypto_certificate_chain_info_from_file()

avs_net_client_key_info_from_buffer()

avs_crypto_private_key_info_from_buffer()

avs_net_client_key_info_from_file()

avs_crypto_private_key_info_from_file()

avs_net_trusted_cert_info_from_path()

avs_crypto_certificate_chain_info_from_path()

9.1.5.5. Refactor of PSK credential handling

avs_net_psk_info_t structure has been changed to use new types based on avs_crypto_security_info_union_t instead of raw buffers. This change also affects avs_net_security_info_t structure which contains the former.

  • Old API:

    /**
     * A PSK/identity pair with borrowed pointers. avs_commons will never attempt
     * to modify these values.
     */
    typedef struct {
        const void *psk;
        size_t psk_size;
        const void *identity;
        size_t identity_size;
    } avs_net_psk_info_t;
    
    // ...
    
    typedef struct {
        avs_net_security_mode_t mode;
        union {
            avs_net_psk_info_t psk;
            avs_net_certificate_info_t cert;
        } data;
    } avs_net_security_info_t;
    
    avs_net_security_info_t avs_net_security_info_from_psk(avs_net_psk_info_t psk);
    
  • New API:

    typedef struct {
        avs_crypto_security_info_union_t desc;
    } avs_crypto_psk_identity_info_t;
    
    // ...
    
    avs_crypto_psk_identity_info_t
    avs_crypto_psk_identity_info_from_buffer(const void *buffer,
                                             size_t buffer_size);
    
    // ...
    
    typedef struct {
        avs_crypto_security_info_union_t desc;
    } avs_crypto_psk_key_info_t;
    
    // ...
    
    avs_crypto_psk_key_info_t
    avs_crypto_psk_key_info_from_buffer(const void *buffer, size_t buffer_size);
    
    /**
     * A PSK/identity pair. avs_commons will never attempt to modify these values.
     */
    typedef struct {
        avs_crypto_psk_key_info_t key;
        avs_crypto_psk_identity_info_t identity;
    } avs_net_psk_info_t;
    
    // ...
    
    typedef struct {
        avs_net_security_mode_t mode;
        union {
            avs_net_psk_info_t psk;
            avs_net_certificate_info_t cert;
        } data;
    } avs_net_security_info_t;
    
    avs_net_security_info_t
    avs_net_security_info_from_psk(avs_net_psk_info_t psk);
    

This change is breaking for code that accesses the data.psk field of avs_net_security_info_t directly.

9.1.5.6. Changes to public configuration macros

avs_commons 4.1 introduced a new header file, avsystem/commons/avs_commons_config.h, that encapsulates all its compile-time configuration, allowing compiling the library without the use of CMake, among other improvements.

This file is included by all other avs_commons headers, so this is not a breaking change in and of itself. However, some configuration macros that were previously #define-d in avsystem/commons/defs.h have been renamed for better namespace separation.

If your code checks for these macros using #ifdef etc., it will need adjustments.

Old macro name

New macro name

WITH_IPV4

AVS_COMMONS_NET_WITH_IPV4

WITH_IPV6

AVS_COMMONS_NET_WITH_IPV6

WITH_X509

AVS_COMMONS_WITH_AVS_CRYPTO_PKI

WITH_AVS_MICRO_LOGS

AVS_COMMONS_WITH_MICRO_LOGS

HAVE_NET_IF_H

AVS_COMMONS_HAVE_NET_IF_H

AVS_SSIZE_T_DEFINED

removed completely

HAVE_SYS_TYPES_H

removed completely

AVS_COMMONS_WITH_MBEDTLS_CUSTOM_ENTROPY_INITIALIZER

removed completely

Important

In the case of WITH_X509, the corresponding CMake variable has also been renamed to WITH_PKI. Attempting to use WITH_X509 will trigger an error.

Note

Aside from the one variable mentioned above, and those removed completely, the CMake variable names have not changed - the renames affect only the C preprocessor.

9.1.5.7. Refactor of avs_net_validate_ip_address() and avs_net_local_address_for_target_host()

avs_net_validate_ip_address() is now no longer used by Anjay or avs_commons. It was previously necessary to implement it as part of the socket implementation. This is no longer required. For compatibility, the function has been reimplemented as a static inline function that wraps avs_net_addrinfo_*() APIs. Please remove your version of avs_net_validate_ip_address() from your socket implementation if you have one, as having two alternative variants may lead to conflicts.

Since Anjay 2.9 and avs_commons 4.6, avs_net_local_address_for_target_host() underwent a similar refactor. It was previously a function to be optionally implemented as part of the socket implementation, but now it is a static inline function that wraps avs_net_socket_*() APIs. Please remove your version of avs_net_local_address_for_target_host() from your socket implementation if you have one, as having two alternative variants may lead to conflicts.

9.1.5.8. Changes in component dependencies

  • avs_net now depends on avs_crypto

    • avs_crypto itself was previously only used for advanced features, only used by the OSCORE commercial feature.

    • In the new version, avs_crypto also contains an abstraction over cryptographically-safe PRNGs.

    • The functionality that comprised the “old” avs_crypto is now controlled by the AVS_COMMONS_WITH_AVS_CRYPTO_ADVANCED_FEATURES compile-time option.

  • avs_vector is no longer compiled by default when building Anjay

  • URL handling routines, previously a part of avs_net, are now a separate component called avs_url

    • You may need to add -lavs_url to your link command if you’re not using CMake to handle dependencies between your project and Anjay

9.1.5.9. Removal of the legacy CoAP component

While the new avs_coap has been used as the CoAP implementation in all versions of Anjay 2.x, the old CoAP component of avs_commons remained in the repository in the 4.0 branch of avs_commons.

This has been removed in avs_commons 4.1 and Anjay 2.3. If your code used the raw CoAP APIs of that component, you will need to migrate to either the new avs_coap library or an entirely different CoAP implementation.

Note

The new avs_coap library has a higher-level API, designed to abstract away the differences between e.g. UDP and TCP transports. Some of the functionality of the legacy library, especially that related to parsing, serializing, sending and receiving raw, isolated messages (as opposed to proper, conformant CoAP exchanges), is not provided in the public API for this reason.