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:
Snap Store (
snap install cmake)Python Package Index (
pip install cmake)
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, orANJAY_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_readargument, but it can also beNULLif 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_receivedargument.
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_STORAGEconfiguration macro inanjay_config.hhas been renamed toANJAY_WITH_ATTR_STORAGE.The
WITH_MODULE_attr_storageCMake option (equivalent to the macro mentioned above) has been renamed toWITH_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 |
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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. Persistence of disabled servers
Core Persistence API (anjay_new_from_core_persistence(),
anjay_delete_with_core_persistence()) now also persists disabled servers
(either by execution of /1/x/4 or call to function from
anjay_disable_server*() family) and the time at which the client shall
reconnect them. Previously those disabled servers weren’t persisted at all and
freshly initialized client was automatically connecting to them without any
regard for specified timeout.
9.1.3.7. Other changes
Declaration of
anjay_smsdrv_cleanup()has been moved fromanjay/core.htoanjay/sms.hin 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_SIZEMAX_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_mtucallback 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 asNULL- 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:
9.1.4.1. avs_coap header rename
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.
9.1.4.2. Context creation API change
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.
9.1.4.3. Changed flow of cancelling observations in case of errors
CoAP observations are implicitly cancelled if a notification bearing a 4.xx or 5.xx error code is delivered.
In Anjay 3.4.x and earlier, this cancellation (which involves calling the
avs_coap_observe_cancel_handler_t callback) was performed before calling
the avs_coap_delivery_status_handler_t callback for the specific
notification. Since Anjay 3.5.0, this order is reversed, so any code that relies
on this logic may break.
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/*.h→avsystem/commons/avs_*.havsystem/commons/stream/*.h,avsystem/commons/stream/stream_*.h→avsystem/commons/avs_stream_*.havsystem/commons/unit/*.h→avsystem/commons/avs_unit_*.h
Below is a detailed list of all renamed files:
Old header file |
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avsystem/commons/avs_socket.havsystem/commons/avs_crypto_pki.h [1] |
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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 |
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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.
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implicit
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prng_ctx field in avs_net_ssl_configuration_t |
Note: It is now mandatory to fill this field when instantiating
a (D)TLS socket.
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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 |
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avs_net_trusted_cert_info_tavs_net_client_cert_info_t |
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avs_net_trusted_cert_info_from_buffer()avs_net_client_cert_info_from_buffer() |
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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 |
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removed completely |
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removed completely |
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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_netnow depends onavs_cryptoavs_cryptoitself was previously only used for advanced features, only used by the OSCORE commercial feature.In the new version,
avs_cryptoalso contains an abstraction over cryptographically-safe PRNGs.The functionality that comprised the “old”
avs_cryptois now controlled by theAVS_COMMONS_WITH_AVS_CRYPTO_ADVANCED_FEATUREScompile-time option.
avs_vectoris no longer compiled by default when building AnjayURL handling routines, previously a part of
avs_net, are now a separate component calledavs_urlYou may need to add
-lavs_urlto 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.
9.1.5.10. Refactor of time handling in avs_sched and avs_coap
It is now enforced more strictly that time-based events shall happen when the clock reaches at least the expected value. Previously, the tasks scheduled via avs_sched were executed only when the clock reached a value later than the scheduled job execution time.
This change will have no impact on your code if your platform has enough clock
resolution so that two subsequent calls to avs_time_real_now() or
avs_time_monotonic_now() will always return different values. As a rule of
thumb, this should be the case if your clock has a resolution no worse than
about 1-2 orders of magnitude smaller than the CPU clock. For example, for a
100 MHz CPU, a clock resolution of around 100-1000 ns (i.e., 1-10 MHz) should be
sufficient, depending on the specific architecture.
If your clock has a lower resolution, you may observe the following changes:
anjay_sched_run()is now properly guaranteed to execute at least one job if the time reported byanjay_sched_time_to_next()passed. Previously this could require waiting for another change of the numerical value of the clock, which could cause undesirable active waiting in the event loop. This is the motivating factor in introducing these changes.Jobs scheduled using
AVS_SCHED_NOW()during an execution ofanjay_sched_run()before the numerical value of the clock changes, will be executed during the same run. The previous behavior more strictly enforced the policy to not execute such jobs in the same run.
If you are scheduling custom jobs through the avs_sched module, you may want or need to modify their logic accordingly to accommodate for these changes. In most typical use cases, no changes are expected to be necessary.
9.1.5.11. Removal of avs_unit_memstream
avs_unit_memstream was a specific implementation of avs_stream_t within
the avs_unit module that implemented a simple FIFO stream in a fixed-size memory
area.
This feature has been removed. Instead, you can use an
avs_stream_inbuf/avs_stream_outbuf pair, or an avs_stream_membuf
object.