I'm only ever going to use sasl_mech="EXTERNAL" with my client code.   I tried using ldap_sasl_bind_s() but that returned with LDAP_SASL_BIND_IN_PROGRESS.

I then used ldap_sasl_interactive_bind_s() based on the example in clients/tools/common.c more or less.    I don't actually need the defaults struct, so I pass defaults=NULL and therefore don't use anything like lutil_sasl_defaults(), etc.

I implemented a LDAP_SASL_INTERACT_PROC using the example in libraries/liblutil/sasl.c which is very similar to lutil_sasl_interact() except that it doesn't support LDAP_SASL_INTERACTIVE and my version of the interaction() function does nothing but return LDAP_SUCCESS.

Looking at it, I could probably shorten my version of the lutil_sasl_interact() to simply return LDAP_SUCCESS and not even bother with an interaction() function.

It appears to work just fine and the debug output says:

ldap_sasl_interactive_bind: user selected: EXTERNAL
ldap_int_sasl_bind: EXTERNAL
ldap_int_sasl_open: host=server1.paxriver.progeny.net
=> ldap_dn2bv(16)
<= ldap_dn2bv(cn=xxxxxxx,ou=xxxxxxx,ou=xxx,o=xxx,dc=xxxx,dc=xxx)=0 
SASL/EXTERNAL authentication started
sasl_interact()
ldap_sasl_bind
ldap_send_initial_request
ldap_send_server_request
ldap_msgfree
ldap_result ld 0x1366940 msgid 2

Thanks,