[strongSwan] Acquiring a DNS server address through config payload

[Martin Willi]

> Is there a way, via configuration, to prevent strongSwan from updating
> the DNS configuration as a result of the configuration payload
> exchange?

Attributes are requested by "attribute handlers" using the enumerator
[1], and handled [2] once received. If no handler is registered or
requests/handles attributes, they are ignored. If --disable-resolve is
passed to ./configure, the resolve plugin is not built and no DNS
information is requested nor handled.

> The custom "attribute handlers" look interesting/useful.  Is there any
> documentation or sample code on it?

There is not much documentation beside the source code. The resolve [3]
plugin itself provides a simple implementation of an attribute handler.
It registers an attribute handler [4] at the attribute manager.

Regards
Martin

[1]http://git.strongswan.org/?p=strongswan.git;a=blob;f=src/libhydra/attributes/attribute_handler.h;h=d042f47e;hb=HEAD#l68
[2]http://git.strongswan.org/?p=strongswan.git;a=blob;f=src/libhydra/attributes/attribute_handler.h;h=d042f47e;hb=HEAD#l48
[3]http://git.strongswan.org/?p=strongswan.git;a=blob;f=src/libhydra/plugins/resolve/resolve_handler.c;h=011ebbaa;hb=HEAD#l186
[4]http://git.strongswan.org/?p=strongswan.git;a=blob;f=src/libhydra/plugins/resolve/resolve_plugin.c;h=f95827ed;hb=HEAD#l70