* Hello message semantics has been made stricter according to RFC 6241 Sec 8.1, for example:
* A client MUST send a <hello> element.
* Each peer MUST send at least the base NETCONF capability, "urn:ietf:params:netconf:base:1.1" (or 1.0 for RFC 4741)
* The netconf client will terminate (close the socket) if the client does not comply
* You can set `CLICON_NETCONF_HELLO_OPTIONAL` to true to use the old behavior of essentially ignoring hellos.
* New clixon-config@2020-03-08.yang revision
* Added: `CLICON_NETCONF_HELLO_OPTIONAL`
* The base capability has been changed to "urn:ietf:params:netconf:base:1.1" following RFC6241.
* Replaces the hardcoded "config" keyword.
* Implemented by a compile-time option called `DATASTORE_TOP_SYMBOL` option in clixon_custom.h
* Tests: added endtest to all tests. Removed all premature exits if BE=0
* Applies to cli/netconf/restconf/client-api code
* Previous behaviour:
* Close socket after each rpc, but now keeps the socket open until the client terminates
* Kept locks over socket life-cycle, but according to RFC 6241 7.5 a lock should be relaeased when session ends
* Netconf split lines input (input fragments) fixed
* Netconf input split on several lines, eg using stdin: "<a>\nfoo</a>]]>]]>" could under some circumstances be split so that only "</a>]]>]]>" be properly processed. This could also happen to a socket receiving a sub-string and then after a delay receive the rest.
* Fixed by storing residue and add that to the input string if later input is received on the same socket.
* Use [https://github.com/clicon/libevhtp](https://github.com/clicon/libevhtp) instead of [https://github.com/criticalstack/libevhtp](https://github.com/criticalstack/libevhtp) as a source of the evhtp source
* Only requests on the form: `<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"><edit-config>...` will be accepted
* All replies will be on the form: `<rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">...`
* Requests such as: `<rpc><edit-config>...` will not be accepted.
* You can revert this behaviour (to clixon pre-4.6 behaviour) by enabling `CLICON_NAMESPACE_NETCONF_DEFAULT`
* This API change is a consequence of: [copy-config's RPC cxobj parameter does not contain namespace #131](https://github.com/clicon/clixon/issues/131)
* Changed commit lock error tag from "lock denied" to "in-use".
* Changed unlock error message from "lock is already held" to #lock not active" or "lock held by other session".
* Fixed [lock candidate succeeded even though it is modified #110](https://github.com/clicon/clixon/issues/110)
Major New features
* New and updated search functions using xpath, api-path and instance-id
* New search functions using api-path and instance_id:
* C search functions: `clixon_find_instance_id()` and `clixon_find_api_path()`
* Binary search optimization in lists for indexed leafs in all three formats.
* This improves search performance to O(logN) which is drastical improvements for large lists.
* You can also register explicit indexes for making binary search (not only list keys)
* For more info, see docs at [paths](https://clixon-docs.readthedocs.io/en/latest/paths.html) and
[search](https://clixon-docs.readthedocs.io/en/latest/xml.html#searching-in-xml)
API changes on existing features (you may need to change your code)
* On failed validation of leafrefs, error message changed from: `No such leaf` to `No leaf <name> matching path <path>`.
* CLI Error message (clicon_rpc_generate_error()) changed when backend returns netconf error to be more descriptive:
* Original: `Config error: Validate failed. Edit and try again or discard changes: Invalid argument`
* New (example): `Netconf error: application operation-failed Identityref validation failed, undefined not derived from acl-base . Validate failed. Edit and try again or discard changes"
Minor changes
* Test framework
* Added `-- -S <file>` command-line to main example to be able to return any state to main example.
* Added `test/cicd` test scripts for running on a set of other hosts
* C-code restructuring
* clixon_yang.c partitioned and moved code into clixon_yang_parse_lib.c and clixon_yang_module.c and move back some code from clixon_yang_type.c.
* partly to reduce size, but most important to limit code that accesses internal yang structures, only clixon_yang.c does this now.
* Fixed multi-namespace for augmented state which was not covered in 4.2.0.
* The multi-namespace augment state may rearrange the XML namespace attributes.
* Mandatory variables can no longer be deleted.
* This occurs in cases where there are more than one XML namespaces in a config tree, such as `augment`:ed trees.
* Affects all parts of the system, including datastore, backend, restconf and cli.
* Invalid api-path syntax (eg non-matching yang) error changed from 412 operation-failed to 400 Bad request invalid-value, or unknown-element.
* Added check for libxml in configure';
* Added clixon_util_regexp utility function
* Yang state get improvements
* Integrated state and config into same tree on retrieval, not separate trees
* Added cli functions `cli_show_config_state()` and `cli_show_auto_state()` for showing combined config and state info.
* Added integrated state in the main example: `interface/oper-state`.
* Added performance tests for getting state, see [test/test_perf_state.sh].
* See [Restconf does not handle startup datastore according to the RFC](https://github.com/clicon/clixon/issues/74)
* Netconf Startup feature is no longer hardcoded, you need to explicitly enable it (See RFC 6241, Section 8.7)
* Enable in config file with: `<CLICON_FEATURE>ietf-netconf:startup</CLICON_FEATURE>`, or use `*:*`
* Start with `-- -r` to run the reset plugin
* Start with `-- -s` to run the state callback
* Rewrote yang dir load algorithm to follow the algorithm in [FAQ](FAQ(doc/FAQ.md#how-are-yang-files-found) with more precise timestamp checks, etc.
* clixon-config YAML file has new revision: 2019-03-05.
* New URN and changed top-level symbol to `clixon-config`
* Removed obsolete `_CLICON_XML_NS_STRICT` variable and `CLICON_XML_NS_STRICT` config option.
* Moved datastore/text/ code to datastore/ since there is only one type of datastore.
* Added "magic script line" to test script for sourced and scriped exits
* Added -p <dir> command-line option to all programs: backend, cli, netconf, restconf.
* Moved and updated all standard ietf and iana yang files from example and yang/ to `yang/standard`.
* Renamed example yang from example.yang -> clixon-example.yang
* For backward compatibility, load of startup and running set CLICON_XML_NS_STRICT to false temporarily.
* Added three-valued return values for several validate functions where -1 is fatal error, 0 is validation failed and 1 is validation OK.
* This includes: `xmldb_put`, `xml_yang_validate_all`, `xml_yang_validate_add`, `xml_yang_validate_rpc`, `api_path2xml`, `api_path2xpath`
* Added new xml functions for specific types: `xml_child_nr_notype`, `xml_child_nr_notype`, `xml_child_i_type`, `xml_find_type`.
* For Example, adding bad-, missing-, or unknown-element error messages, etc instead of operation-failed
* Removed delete-config support for candidate db since it is not supported in RFC6241.
* Switched the order of `error-type` and `error-tag` in all netconf and restconf error messages to comply to RFC order.
* Added example_rpc RPC to example backend
* Renamed xml_namespace[_set]() to xml_prefix[_set]()
* Some restconf error messages contained "rpc-reply" or "rpc-error" which have now been removed.
* Netconf/Restconf RPC extra input arguments are ignored (https://github.com/clicon/clixon/issues/47)
* NACM module support (RFC8341 A1+A2)
* Recovery user "_nacm_recovery" added.
* Example use is restconf PUT when NACM edit-config is permitted, then automatic commit and discard are permitted using recovery user.
* Example user changed adm1 to andy to comply with RFC8341 example
* Yang code upgrade (RFC7950)
* RPC method input parameters validated
* see https://github.com/clicon/clixon/issues/4
* Correct XML namespace handling
* XML multiple modules was based on "loose" semantics so that yang modules were found by iterating thorugh namespaces until a match was made. This did not adhere to proper [XML namespace handling](https://www.w3.org/TR/2009/REC-xml-names-20091208), and causes problems with overlapping names and false positives. Below see XML accepted (but wrong), and correct namespace declaration:
```
<rpc><my-own-method></rpc> # Wrong but accepted
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> # Correct
<my-own-method xmlns="http://example.net/me/my-own/1.0">
</rpc>
```
* To keep old loose semantics set config option CLICON_XML_NS_ITERATE (true by default)
* XML to JSON translator support for mapping xmlns attribute to module name prefix.
* Default namespace is still "urn:ietf:params:xml:ns:netconf:base:1.0"
* See https://github.com/clicon/clixon/issues/49
* Changed all make tags --> make TAGS
* Keyvalue datastore removed (it has been disabled since 3.3.3)
* debug rpc added in example application (should be in clixon-config).
* Improved unknown handling
* Configure option `CLICON_YANG_DIR` is changed from a single directory to a path of directories
* Note CLIXON_DATADIR (=/usr/local/share/clixon) need to be in the list
