Added two new config options to clixon-config.yang: `CLICON_HTTP_DATA_ROOT`
Added new files: apps/snmp/snmp_mib_yang.[ch] for generic MIB/YANG handling
Test: killall quiet
Test: added specific MIB for generic code: <CLICON_SNMP_MIB>NET-SNMP-EXAMPLES-MIB</CLICON_SNMP_MIB>
Integrated netsnmp agent and clixon event handling, made a workaround of fdset:s
used in the netsnmp API with sockets used in Clixon
Added a hardcoded MIB OID handler as subagent
Added libnetsnmpagent to autotools dependency check
New OE_SNMP error code
* In the autocli and handcrafted CLI:s using `expand_dbvar()` the CLI expansion followed the leafrefs to the sources, ie the origin of the leafrefs
* Instead leafref expansion now only looks at the leafrefs
* Fixed: [Error message seen twice in some cases](https://github.com/clicon/clixon/issues/325)
* Extended `-l` command-line option to all clixon commands with a `none` option, eg `-l n` directs logging to `dev/null`
* `-0` means dont send hello, but fix netconf base version to 0 and use EOM framing
* `-1` means dont send hello, but fix netconf base version to 1 and use chunked framing
* Indirect redirects from directory to `index.html`
* Added `HTTP_DATA_INTERNAL_REDIRECT` compile-time option
* Added CLICON_RESTCONF_API_ROOT to clixon-config.yang
* Added 404 return without body if neither restconf, data or streams prefix match
* Fixed: HTTP/1 parse error for '/' path
Check data paths for .., ~ and soft links
Changed semantics of `CLICON_HTTP_DATA_PATH` and `_ROOT`
Change URI catch-all to 404 instead of 400
Fixed some memory leaks
Check of enable-http-data config option
HTTP/2 Return 400 bad request if no path match
Test: updated yang file revisions, extended restconf config with http-data
* This is an experimental implementation
* Added `www-data` feature and two new config options to clixon-config.yang:
* `CLICON_WWW_DATA_PATH`
* `CLICON_WWW_DATA_ROOT`
* The limited implemtation is as follows:
* path: Local files within `CLICON_WWW_DATA_ROOT`
* operation GET, HEAD, or OPTIONS
* query parameters not supported
* indata should be NULL (no write operations)
* Limited media: text/html, JavaScript, image, and css
* Authentication as restconf
Generic changes:
* Uniform path selection across fcgi, native http/1 + http/2
