[strongSwan] plugins load warnings

[Volodymyr Litovka]

Hi colleagues,

I'm installing and configuring Strongswan inside VM (KVM on Intel Xeon 
CPU D-1521) with Ubuntu 17.10.

With all plugins enabled, when I start strongswan service, I see the 
following messages in the log:

1) The first question is how this impact performace, whether it need to 
be loaded and how? -
Mar  2 15:32:44 vpn strongswan: 00[LIB] feature CUSTOM:kernel-ipsec in 
plugin 'kernel-netlink' failed to load

2) plugin "pem" has unmet dependencies - not sure it's important, just 
ask in case - should it be?

Mar  2 15:32:44 vpn strongswan: 00[LIB] feature PUBKEY:DSA in plugin 
'pem' has unmet dependency: PUBKEY:DSA
Mar  2 15:32:44 vpn strongswan: 00[LIB] feature PRIVKEY:DSA in plugin 
'pem' has unmet dependency: PRIVKEY:DSA
Mar  2 15:32:44 vpn strongswan: 00[LIB] feature CERT_DECODE:OCSP_REQUEST 
in plugin 'pem' has unmet dependency: CERT_DECODE:OCSP_REQUEST

Loaded modules list -

Mar  2 15:32:44 vpn strongswan: 00[LIB] loaded plugins: charon 
test-vectors unbound ldap pkcs11 aesni aes rc2 sha2 sha1 md4 md5 mgf1 
rdrand random nonce x509 revocation constraints acert pubkey pkcs1 pkcs7 
pkcs8 pkcs12 pgp dnskey sshkey dnscert ipseckey pem openssl gcrypt 
af-alg fips-prf gmp agent chapoly xcbc cmac hmac ctr ccm gcm ntru bliss 
curl soup mysql sqlite attr kernel-libipsec kernel-netlink resolve 
socket-default connmark farp stroke vici updown eap-identity eap-sim 
eap-sim-pcsc eap-aka eap-aka-3gpp2 eap-simaka-pseudonym 
eap-simaka-reauth eap-md5 eap-gtc eap-mschapv2 eap-dynamic eap-radius 
eap-tls eap-ttls eap-peap eap-tnc xauth-generic xauth-eap xauth-pam 
xauth-noauth tnc-tnccs tnccs-20 tnccs-11 tnccs-dynamic dhcp whitelist 
lookip error-notify certexpire led radattr addrblock unity

Thank you.

-- 
Volodymyr Litovka
   "Vision without Execution is Hallucination." -- Thomas Edison